The price of a custom lithium battery pack is mainly composed of three major components: battery cell, PCM, and casing. At the same time, due to the current of the electrical appliances, the material of the connecting piece between the cells (conventional nickel sheet, formed nickel sheet, copper-nickel composite sheet, jumper sheet, etc.) or selection, different connectors (such as Special plugs, ranging from tens to thousands of dollars) may also have a greater impact on the cost. In addition, different PACK manufacturing processes will also affect the cost.
Battery cell selection
Depending on the cathode material, custom lithium battery pack include lithium manganate (3.6V), lithium cobalt oxide (3.7V/3.8V), lithium nickel cobalt manganate (commonly known as ternary, 3.6V), and lithium iron phosphate (3.2V). , lithium titanate (2.3V/2.4V) and other battery cores of various material systems. Batteries made of different materials have different voltage platforms, safety factors, number of cycles, energy density, operating temperatures, etc.
Requirements and design of custom lithium battery pack PCM
PCM design can be divided into: basic protection, communication, BMS
Basic protection: Basic protection includes overcharge, over-discharge, over-current and short-circuit protection. Over-temperature protection can be added according to product needs.
Communication: Communication protocols can be divided into I2C, RS485, RS232, CANBUS, HDQ, SMBUS, etc. There is also a simple power display, which can be indicated by a power meter using LED.
BMS: Mainly to intelligently manage and maintain each battery unit, prevent the battery from overcharging and over-discharging, extend the service life of the battery, and monitor the status of the battery. Its main functions include: real-time monitoring of battery physical parameters; battery status estimation; online diagnosis and early warning; charge, discharge and precharge control; equalization management and thermal management, etc. Subsystems are mostly used in electric vehicle batteries.
What kind of outer shell packaging form is used mainly depends on the specific needs of the customer’s product. It can be mainly divided into: PVC heat shrink film, plastic shell, metal shell
PVC heat shrink film: generally suitable for battery packs with a small number of cells in series and in parallel and a light overall weight. However, for battery packs with a relatively large overall weight, fixed brackets can be added between the cells, and fiberglass boards are added to the periphery for protection, and then PVC heat sealing is used. PVC heat shrink film is also the most economical packaging method.
Plastic case: Mainly because after different battery packs are finalized, the cases involved may need to be molded. The mold cost is a large expense. If the product is not finalized in the early stage of development, a prototype shell can be used for proofing. Different material and process requirements for the shell will also affect the cost.
Metal casel: The metal case is the same as the plastic case. Before the product is finalized or the quantity demand is not large, it is recommended to use sheet metal sample preparation, which mainly shortens the sample preparation and delivery time. If the order quantity is large, it is recommended to open a mold. There are waterproof level requirements for metal casings, which will also greatly affect the cost. Metal casings made of special materials (such as titanium alloy, etc.) will also increase the cost.
At the same time, due to different product technical difficulty, procurement volume, and defective rate requirements, lithium battery prices will vary greatly!
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With the increase in solar panels on houses and plug-in cars patrolling the roads, custom lithium battery pack is going to be ever more important in the coming years.
Technology has shown the way to harnessing power from the sun and other sources in nature, but what to do with that power once harvested? Researchers and students from Chico State are going to be among a group coming up with a better battery.
Most parts of California, for example, enjoy more than 280 days of sunshine per year—a real bounty for capturing solar energy. However, the substantial challenge is storing that power for use at night or on overcast days.
Members of Chico State’s faculty will work to overcome this problem and they have money to help them do it—a three-year,$2.25 million grant from the federal Department of Energy’s Office of Electricity and the Office of Basic Energy Services. The university will receive half of that money—funding a collaborative research project to maximize the storage capacity of low-cost batteries.
San Jose State and the Lawrence Livermore National Laboratory are the other participants in the project and will receive the other half of the funding.
Monica So, principal investigator and associate professor in Chico State’s Department of Chemistry and Biochemistry, joins Kathleen Meehan, co-principal investigator and professor in the Department of Electrical and Computer Engineering, to help coordinate this project. The other principal investigators involved are Philip Dirlam from San Jose State and Liwen Wan from Lawrence Livermore.
The center of this effort is the lithium-sulfur battery—much like a watch battery—that is lighter that its current “king of the hill” model, the lithium ion unit.
“We’re actually trying to enhance the storage cap of lithium-sulfur batteries. They’re potentially a safer alternative to custom lithium battery pack and the storage capacity is higher,” So explained. “We’re trying to enhance performance by modifying the materials that make up certain components.”
Batteries typically have two electrodes. “We’re trying to create materials to improve the anode, then we’re going to put them in a lithium-sulfur coin cell”—about the diameter of a dime.
That won’t be the final size the researchers will strive to create.
“The overall size of prototype is like a watch battery, which we can scale up to a car battery, storing energy generated at a house or solar farm,” Meehan said.
“The weight and size will be smaller than what’s needed for a lithium-ion battery. We will halve its size. That will allow the battery to drive its car longer because it won’t need as much to make the wheels move” due to its reduced weight.
It’s no easy undertaking and the process is slow, Meehan said.
“The time to market hasn’t changed that much over the decades,” she said. “With lithium-sulfur batteries, we expect about 10 years to have some on the market. Historically, it has taken 20 years to move something from advanced research to manufacture.
“That length of time hasn’t moved that much. Nothing ever goes from small scale to large scale completely smoothly.”
The project began in August. The grant will enable Chico State and San Jose State to purchase state-of-the-art equipment, provide research materials and supplies to be used in the development and characterization of the lithium-sulfur batteries and fund travel to conferences where the investigators and participants can discuss their research findings with other researchers in the field.
“Ideally, in three years we’ll have a working prototype,” So said.
Principal investigators will also contribute the research training and professional development of the 22 students and two postdoctoral scholars, creating a local pool of talented scientists and engineers who can continue to develop technologies for a more sustainable energy future, a Chico State press release said.
So said she and Meehan found out about the grant opportunity in January and had four months to formulate a proposal. They submitted the proposal to the Department of Energy in May.
Federal officials will make sure the three institutions involved are making good use of the funds.
“The DOE does care about deliverables and the quality of work. I just met with them two weeks ago,” So said. “They do care that we make progress on this, and that we publish academic papers.
“They also expect we’ll recruit and retain participants—22 students from Butte County and Santa Clara County, plus two early-career scientists. They’ll track development.”
She added that the investigators will recruit undergraduate students from Butte College and other area community colleges.
Meehan said increasing the ranks of groups not historically represented in electrical engineering and chemistry is also an objective.
“One of our goals is to recruit people who are typically not in this discipline—women, Latinos, African-Americans and Native Americans,” she said.
Referring to herself and So, as females, Meehan said,”We’re outliers in our field—there are only about 10% of women in electrical enginnering. Blacks make up about 3%. So it doesn’t match the general population.
“The more we can pull in, it would be good. It creates a fuller idea of what a product should be and how we should be doing our research.”
Having more underrepresented groups also makes products like improved batteries more widely available in the long run, as there will be a larger group offering suggestions on how to make the custom lithium battery pack better. The grant is part of a $70 million package through the Department of Energy’s RENEW Initiative, which aims to support research by historically underrepresented groups in science, technology, engineering and mathematics.
“They can contribute more fully to the development, and also make sure the product serves as many people as possible,” Meehan said.
(c)2023 Chico Enterprise-Record, Calif Distributed by Tribune Content Agency, LLC.
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Let’s talk about some details of the tin-based tandem electrocatalyst for the synthesis of ethanol via CO₂ reduction and li ion customized battery manufacturing process.
The electrochemical reduction of carbon dioxide (CO2) into various multi-carbon products is highly desirable, as it could help to easily produce useful chemicals for a wide range of applications. Most existing catalysts to facilitate CO2 reduction are based on copper (Cu), yet the processes underpinning their action remain poorly understood.
Researchers at the Chinese Academy of Sciences, City University of Hong Kong, and other institutes in China have recently set out to design more efficient Cu-free electrochemical catalysts for the reduction of CO2 Their paper, published in Nature Energy, introduces a new catalyst based on Tin (Sn), which was found to reduce CO2 to ethanol (CH3CH2OH) with a selectivity of 80%.
“The discovery of C-C coupling over the Sn1-O3G catalyst was not accidental, but instead built on our earlier works on understanding the CO2RR behavior of transition metal single-atom catalysts,” Prof. Bin Liu, co-author of the paper, told Tech Xplore.
“Specifically, we conducted preliminary experiments involving structural and electrochemical characterizations of various Sn-based CO2RR catalysts, including metallic Sn nanoparticles, SnS2 nanosheets, SnS2 on nitrogen-doped graphene, single Sn atoms on nitrogen-doped graphene (Sn-4N) and single Sn atoms on O-rich graphene (Sn1-O3G).”
In their preliminary experiments, the researchers found that both Sn1-4N and Sn1-O3G catalysts could reduce CO2 to CO with KHCO3, as a proton donor in a CO2RR solution. However, these catalysts displayed different behavior in the presence of the acid formate, with only Sn1-O3G ultimately producing ethanol.
“These observations led us to believe that the difference in CO2RR between the Sn1-4N and Sn1-3OG catalysts could result from the different coordination environments of Sn,” Prof. Liu said. “Thereafter, we focused our efforts on understanding the C-C coupling mechanism on O-coordinated Sn catalytic sites and constructed a tandem catalyst to realize selective CO2RR to ethanol.”
Prof. Liu and his colleagues fabricated their new Sn-based electrocatalyst by eliciting a solvothermal reaction between SnBr2 and thiourea on a three-dimensional (3D) carbon foam. They subsequently examined their catalyst to characterize its structure.
Their examinations suggest that their catalyst is made up of SnS2 nanosheets and atomically dispersed Sn atoms. These components are coordinated on the 3D O-rich carbon by binding with three O atoms (Sn1-O3G).
“The electrochemical performance of the SnS2/Sn1-O3G catalyst for CO2RR was evaluated using chronoamperometry in an H-type cell containing CO2-saturated 0.5-M KHCO3,” Prof. Liu said. “Our catalyst can reproducibly yield ethanol with a Faradaic efficiency (FE) of up to 82.5% at -0.9 VRHE and a geometric current density of 17.8 mA cm–2. Additionally, the FE for ethanol production could be maintained at above 70% over the potential window from -0.6 to -1.1 VRHE.”
In initial evaluations, the catalyst developed by the researchers achieved highly promising results, successfully producing ethanol from a CO2RR solution with a high selectivity. In addition, the catalyst was found to be stable, maintaining 97% of its initial activity after 100 h of operation.
“The dual active centers of Sn and O atoms in Sn1-O3G serve to adsorb different C-based intermediates, which effectively lowers the C-C coupling energy between *CO(OH) and *CHO,” Prof. Liu explained. “Our tandem catalyst enables a formyl-bicarbonate coupling pathway, which not only provides a platform for C-C bond formation during ethanol synthesis and overcomes the restrictions of Cu-based catalysts but also offers a strategy for manipulating CO2 reduction pathways towards desired products.”
The recent work by this team of researchers introduces an alternative Cu-free catalyst for eliciting the C-C bond formation and enabling the reduction of CO2 to ethanol. In the future, their proposed approach could be used to produce ethanol more reliably and could potentially also be applied to the synthesis of other desired chemical products via the CO2 reduction reaction.
“The search for more efficient catalysts with dual active sites should be pursued through high-throughput experiments and theoretical calculations,” Prof. Liu added. “The rate and selectivity of a catalytic reaction are also closely related to the coverage of reaction intermediates on the catalyst‘s surface.
“Therefore, an in-depth study of factors that affect the residence time of intermediates, such as the pore structure of the support for the Sn1-O3G dual-active sites, would help to deepen understanding of the C-C coupling process. We envisage that tandem catalysis based on the concept of dual-active sites could be extendable to C-X (X = N or S) coupling to prepare other chemicals, such as urea and alanine.”
More information: Jie Ding et al, A tin-based tandem electrocatalyst for CO2 reduction to ethanol with 80% selectivity, Nature Energy (2023). DOI: 10.1038/s41560-023-01389-3
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The product consistency and safety of cylindrical lithium-ion battery are better. Cylindrical li ion customized battery packs are the earliest mature industrial lithium-ion battery products. The 18650 lithium-ion battery was first launched by Sony Corporation of Japan in 1992. At that time, the important application direction was 3C digital products. After more than two decades of development, cylindrical custom lithium battery pack have a mature production process, high production efficiency and relatively low cost, so the packaging cost is also relatively low. The yield of 18650 lithium ion battery pack is higher than that of prismatic lithium-ion batteries and LiPO li ion customized battery packs.
Cylindrical lithium-ion batteries have better heat dissipation performance than prismatic batteries due to their large heat dissipation area; cylindrical batteries are easy to combine into various forms and are suitable for full-layout electric vehicle space design. Based on these advantages, most domestic companies choose cylindrical batteries in the power supply field.
Prismatic lithium-ion battery:
Prismatic lithium-ion battery casings are mostly made of aluminum alloy, stainless steel, etc. The internal winding or lamination technology protects the battery better than soft batteries, and the safety of the battery is greatly improved compared to cylindrical batteries. At present, prismatic batteries are still developing towards high-hardness shells and lightweight technology, which will also provide the market with li ion customized battery packs products with better performance.
LiPO battery:
Small thickness, light weight, large capacity and good safety performance.
Li-PO batteries can be arbitrarily changed in size according to customer requirements. The structure of Li-PO batteries uses aluminum-plastic soft packaging, which is different from the metal casing of liquid batteries. Once a safety hazard occurs, the Li-PO batteries will only swell but not explode.
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When designing custom lithium battery pack, it is very important to correctly calculate the reasonable ratio of positive and negative electrode capacities. For traditional graphite negative electrode lithium-ion batteries, the main shortcomings of battery charge and discharge cycle failure mainly occur in lithium deposition and dead zone problems on the negative electrode side, so the solution of excess negative electrode is usually used. In this case, the battery capacity is limited by the capacity of the positive electrode, and the ratio of negative electrode capacity/positive electrode capacity is greater than 1.0 (i.e. N/P ratio >1.0).
If there are too many positive electrodes, excess lithium ions from the positive electrode cannot enter the negative electrode during charging, and lithium will be deposited on the surface of the negative electrode, leading to the formation of dendrites, thus affecting the cycle performance of the battery. Therefore, generally speaking, the graphite negative electrode in custom lithium battery pack will have slightly more than the positive electrode, but not too much. Too much negative electrode will consume the lithium in the positive electrode. In addition, this will also cause waste of negative electrodes, reduce battery energy density, and increase battery costs.
For lithium titanate anode batteries, due to the relatively stable LTO anode structure, high voltage platform, excellent cycle performance, and no lithium deposition, battery cycle failure mainly occurs on the cathode side. The preferred solution for battery system design is to use excess positive and negative capacity limits (N/P ratio <1.0), which can alleviate electrolyte decomposition problems due to high positive electrode potential when the battery is near or fully charged.
N/P ratio refers to the ratio of negative electrode capacity to positive electrode capacity. Actually, there is another way of saying it, called CB (Battery Balancing). Generally speaking, the ratio of positive and negative electrodes in a battery is mainly determined by the following factors:
Efficiency of positive and negative electrode materials: All reactive substances should be considered, including conductive agents, binders, current collectors, separators and electrolytes.
Coating accuracy of the equipment: Now the ideal coating accuracy can reach 100%. This factor needs to be considered if the coating accuracy is not high.
Cyclic decay rate of positive and negative electrodes: If the positive electrode decays faster, then the N/P ratio is lower than the design value, leaving the positive electrode in a shallow charge and discharge state. On the other hand, if the negative electrode decays quickly and the N/P ratio is high, the negative electrode will be in a shallow state of charge and discharge.
The rate capability the battery needs to achieve. The calculation formula of N/P is: N/P = negative electrode area density × active material ratio × active material discharge specific capacity / positive electrode area density × active material ratio × active material discharge specific capacity. For example: in the voltage range of 4.2 ~ 3.0V, at 25°C, the first round charge and discharge efficiency of LiCoO2 is about 95%, and the first round charge and discharge efficiency of ternary materials is between 86% and 90%. Table 1 shows the mass specific capacity of commercial NCM111 under 1C discharge for the first three charge-discharge cycles.
Before using material ratios, calculations can be made based on first-round efficiency data provided by the material manufacturer. If the manufacturer does not provide these data, it is best to test the first-run efficiency of the material using a button half cell in order to calculate the ratio of positive to negative electrodes. The ratio of positive and negative electrodes in graphite negative electrode lithium batteries can be calculated based on the empirical formula N/P = 1.08, where N and P are the mass specific capacities of the active materials of the negative electrode and positive electrode respectively.
The calculation formulas are as follows (1) and (2). Excess negative electrode helps prevent lithium from depositing on the surface of the negative electrode when the battery is overcharged, and helps improve the cycle life and safety of the battery. N = Negative electrode area density × active material ratio × active material discharge specific capacity (1); P = positive electrode area density × active material ratio × active material discharge specific capacity (2).
Assuming that the positive electrode area density is 200 mg/cm2, the active material ratio is 90%, and the specific discharge capacity is 145 mAh/g, then P = 200 mg/cm2 × 0.9 × 145 mAh/g = 26.1 mA hour/cm2. Assuming that the active material ratio of the negative electrode is 95% and the specific discharge capacity is 320 mAh/g, it is more appropriate to design the areal density of the negative electrode to 93 mg/cm2. At this time, N = 93 mg/cm2 × 0.95 × 320 millimeter Ampere-hour/gram = 28.3 mA-hour/cm2, N/P = 1.084.
Because the irreversible capacity of the custom lithium battery pack material in the first round will also affect the ratio of positive and negative electrodes, the above calculation should also be verified with the first round charging capacity. According to Table 2, the first round charge and discharge efficiency of LiCoO2 is 95%, the first round charge and discharge efficiency of NCM111 is 86%, and the first round charge and discharge efficiency of the negative electrode is 90%. Their charging capacities are 153 mAh/g, 169 mAh/g and 355 mAh/g respectively.
PLCO=27.54 mA·h·cm–2
N=31.36 mA·h·cm–2
N/PLCO=1.138
P111=30.42mA·h·cm–2
N/P111=1.03
Generally speaking, the N/P ratio calculated based on charging capacity should be greater than 1.03. If it is lower than 1.03, you need to fine-tune the ratio of positive and negative electrodes again. For example, when the first-round efficiency of the positive electrode is 80%, the above-mentioned positive charging capacity is 181 mAh/g, then P = 32.58 mAh/cm2, N/P = 0.96. At this time, the surface density of the positive and negative electrodes should be adjusted so that N/P is greater than 1, preferably around 1.03. For mixed cathode materials, calculations also need to be performed according to the above method.
Effects of different N/P ratios on the performance of lithium titanate negative electrode custom lithium battery pack
The impact of different N/P ratios on custom lithium battery pack capacity
In this study, a flexible packaging lithium-ion battery was prepared using ternary NCM as the positive electrode material and lithium titanate LTO as the negative electrode material; the experimental plan was to keep the positive electrode capacity unchanged and change the negative electrode capacity, that is, set the positive electrode capacity to 100 , and then designed the negative electrode capacities of 87, 96, 99 and 102 respectively, as shown in Figure 2. When the N/P ratio is less than 1.0, the negative electrode capacity is insufficient, the positive electrode capacity is too much relative to the negative electrode capacity, and the battery capacity is limited by the negative electrode capacity;
When the negative electrode capacity is high, that is, when the N/P ratio increases, the battery capacity increases accordingly; when N/P is greater than 1.0, the cathode capacity is insufficient relative to the negative electrode capacity, and the battery capacity is limited by the positive electrode capacity. Even if the negative electrode capacity is increased, the battery capacity will not change. It can be seen that under this experimental scheme, as the N/P ratio increases, the battery capacity also increases.
The full custom lithium battery pack capacity test also verified the above analysis. As shown in Figure 3(a), as the N/P ratio increases, the full battery capacity increases from 2430 mA h to 2793 mA h. By calculating the gram capacity of the positive and negative electrode materials, the changing trend of the gram capacity with the N/P ratio can be obtained. As shown in Figure 3(b), it can be seen that increasing the N/P ratio can increase the gram capacity of the cathode material and the battery capacity.
Effects of different N/P ratios on battery high-temperature storage performance
The high temperature storage (60°C, 100% SOC) test is to charge at 1.0C to 2.8V/0.1C cut-off, leave it for 5 minutes, charge at 1.0C to 1.5V, cycle 3 times, and select the one with the highest capacity as the initial capacity; then , test the full charging voltage, internal resistance and thickness of the battery before storage, and record these values;
After storing the battery at 60°C for 7 days, measure the full charge voltage, internal resistance and fully charged thickness of the corresponding battery. Then discharge the battery to 1.5V at 1.0C, record the remaining capacity, charge at 1.0C to 2.8V/0.1C cutoff, leave it for 5 minutes, and discharge at 1.0C to 1.5V. The discharge capacity after 3 cycles was recorded as the recovery capacity, and the test results are shown in Figure 3(a).
Effects of different N/P ratios on battery cycle performance
NCM/LTO system batteries with three different N/P ratios (0.87/0.99/1.02) were used for 3C charging and 3C discharge cycle tests. The voltage range was 2.8 to 1.5V. Cycle capacity retention rates under the three N/P ratios As shown in Figure 5(a). As can be seen from the figure, the battery with an N/P ratio of 0.87 has the best cycle performance, with a capacity retention rate of 97% after 1,600 cycles. However, when the N/P ratio increases to 0.96 and 1.02, the cycle capacity retention rate decreases significantly.
The change rate of internal resistance during the cycle is shown in Figure 5(b). When the N/P ratio is 0.87, the internal resistance increase rate is the smallest. After 1800 cycles, the internal resistance increased by 7.6%. When the N/P ratio increases to 1.02, the internal resistance increases sharply to 34% after 1800 cycles. It can be seen that the N/P ratio design of the battery has a great impact on the cycle performance, and a lower N/P ratio is more beneficial to the cycle performance of the battery.
Three-electrode test with different N/P ratios
Three-electrode tests were performed on cells with different N/P ratios. The test conditions are 3C constant current charging to 2.8V, 0.1C cutoff, 30 minutes of sleep, and 3C discharge to 1.5V. The test results are shown in Figure 6.
The positive electrode potential of the battery with an N/P ratio of 0.87 dropped from 4.325 V at the beginning of constant voltage charging to 4.295 V at the end of constant voltage charging, and then continued to drop to 4.215 V during the 30-minute rest period. The positive electrode potential of the battery with an N/P ratio of 1.00 remained basically unchanged during the constant voltage charging stage, and only dropped to 4.321 V during 30 minutes of rest.
The negative electrode potential of the battery with an N/P ratio of 0.87 dropped from 1.56 V to 1.50 V, while the negative electrode potential of the battery with an N/P ratio of 1.00 remained basically unchanged, only decreasing from 1.56 V to 1.54 V. The battery voltage of the battery with an N/P ratio of 0.87 dropped from 2.8 V to 2.69 V during 30 minutes of rest, while the voltage of the battery with an N/P ratio of 1.00 remained basically unchanged, only dropping from 2.8 V to 2.77 V.
It can be seen that the battery with lower N/P has a larger positive electrode potential drop during the constant voltage charging stage and subsequent resting process. The positive electrode potential of a battery with an N/P of 0.87 is significantly lower than that of a battery with an N/P of 1.0. It can be seen from the three-electrode test results that for the LTO negative electrode, the voltage platform is around 1.55 V, and most electrolyte solvents have stable electrochemical performance on the lithium titanate negative electrode side.
However, the potential on the positive electrode side is higher, and the electrolyte is prone to oxidation reactions on the positive electrode side, especially when it is close to a fully charged state. Therefore, for a battery system with an N/P ratio less than 1 (LTO capacity is limited), when the battery is fully charged, the negative electrode potential will drop from 1.56 V to 1.50 V, and the positive electrode potential will drop from 4.325 V to 4.295 V, and then continues to drop to 4.215 V during the 30-minute sleep depolarization process;
For battery systems with an N/P ratio greater than 1 (positive electrode capacity is limited), there is too much LTO relative to the positive electrode, and the potential of LTO remains basically unchanged during the charging process, only decreasing from 1.56 V to 1.54 V. The positive electrode potential remains unchanged during constant voltage charging, which is 4.295 V higher than the positive electrode potential in batteries with a low N/P ratio. The higher positive electrode potential state makes side reactions such as oxidation between the electrolyte and the positive electrode more likely to occur, resulting in poor cycle performance and high-temperature storage performance.
Conclusion For lithium titanate negative electrode lithium-ion batteries, increasing the N/P ratio will help increase the positive electrode gram capacity of the battery and help increase the initial discharge capacity of the battery; however, increasing the N/P ratio will increase the positive electrode potential, The electrolyte is prone to oxidation reactions on the cathode side, especially when it is close to a fully charged state. The low N/P ratio can ensure that the positive electrode has a lower electrode potential, thereby reducing the internal side reactions of the battery during high-temperature storage and cycling, which helps to improve the high-temperature storage performance of the battery and the cycle performance of lithium batteries. When the energy density requirement is not high, in order to ensure long life cycle and good high temperature performance, the N/P ratio can be moderately reduced to between 0.85 and 0.9.
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The energy density of li ion customized battery packs is 48% higher than that of Ni-MH batteries. And its cycle life of charge and discharge times can reach more than 600 times.
Advantages of li ion customized battery packs: small self-discharge, no memory effect, small size, light weight, green and environmental protection.
Application fields: transportation power supply, energy storage power supply, mobile communication power supply, new energy energy storage power supply, aerospace special power supply, electric vehicle applications.
Ni-MH battery is a battery with excellent performance. As an important direction of hydrogen energy application, hydrogen energy has attracted more and more attention.
Advantages: low price, strong versatility, large current, strong reliability, good over-discharge performance, overcharge protection, high charge-discharge rate, no dendrite-formation, good low-temperature performance, no significant change in capacity at -10 °C.
In recent years, more and more Ni-MH batteries are used. The capacity is getting larger and larger, chargers are becoming more and more advanced, and the charging time is greatly shortened.
Uses: electric toys, electric bicycles, power tools, digital products.
Conclusion: In terms of daily charging, li ion customized battery packs have no memory effect and are easy to use. In addition, li ion customized battery packs are light in size and weight, making them easy to carry on mobile devices. The working voltage of the Ni-MH battery is 1.2V~1.5V, and the series voltage of the two batteries is 2.4V~3.0V. Most electrical appliances already have this operating voltage standard, such as walkman, radio, etc. Therefore, in the civil battery, lithium-ion batteries cannot replace Ni-MH batteries. However, in the later development of new electrical appliances, such as mobile phone batteries, camera batteries, mobile power supplies, etc., li-ion battery is more popular now.
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We know the importance of li ion customized battery packs and solid-state batteries. Despite the importance of solid-state batteries, But in its publicity and boasting, there’s something less clear. This article lists ten topics to provide a clearer understanding of solid-state batteries, but we need to put these topics into the correct context and be alert to missing information.
Safety – Undoubtedly the most important factor Let’s start at the beginning, which is also the original and hopefully still the main reason for solid state batteries. The reason for this is safety, which is directly related to the temperature limits of the liquid electrolyte. We all know about thermal runaway in current li ion customized battery packs: rare, but unstoppable fires. When the battery is unable to discharge heat at the rate it is being produced, a chain reaction begins. Current li ion customized battery packs are kept operating within a safe temperature range, typically around 25-45°C, by cooling systems and battery management systems (BMS). Typically, a battery requires failure, defect, misuse, or accident to cause overheating. Unfortunately, with billions of batteries present in millions of electric vehicles and energy storage systems, these problems are statistically inevitable. Therefore, we should not pretend that risk can be eliminated by design, but rather that the sources of risk must be eliminated. Liquid electrolytes are discussed further below (#3) and lithium compatibility (#5), as well as new risks such as hydrogen sulfide (#8). Summary: Security remains a top concern, so we need to keep talking about it.
Pressure – An often overlooked issue People seem to think that solid electrolytes require a pressure system. Eminent scientists say the solid-state problem has been solved in the laboratory and now it’s up to engineers to design a pressure system. Indeed, it has been shown that lithium metal deposition can be enhanced by increasing pressure. But while some pressure can be easily integrated (e.g., vacuum on a vacuum-sealed bag), for many solid-state batteries the high voltages required remain impractical for practical applications. The high voltage is used to overcome interfacial resistance, especially for oxides and sulfides. Some solid-state polymers do not require pressure, but perhaps surprisingly, hybrid and semi-solid batteries require high voltages. If high voltage is required, the problem is compounded by changes in volume of the battery as it charges and discharges, heats and cools. There is a lack of transparency into this complex issue, as pressuring the system can add significant expense and quality. Quoting improved energy density is inappropriate without acknowledging additional pressure systems. QuantumScape recently provided energy density data “unpackaged” to give it some credit. Maybe a bit cryptic, but this suggests the battery needs more content to run. Summary: Operating pressure is often ignored in performance claims, but it has important implications for energy density, cost, and scalability. (See the next topic for information on scalability).
Liquid – Does a solid have to be a true solid? This topic is crucial because liquids can cause issues with safety and pressure (#1&2 above) as well as temperature range (#4 below). Many products are called solid state because the separator is a solid electrolyte. The inactive porous polymer separator is replaced by an active solid-state electrolyte that excels in both mechanical strength and ionic conductivity. It maintains electrode spacing, resists dendrites (see Topic #5) and transports lithium ions. But the cathode also requires an electrolyte (unless a very thin film cathode is used), and if this electrolyte is a liquid or gel, then we need to evaluate safety risks and performance issues. The risks of liquid electrolytes are explained in Topic #1. Topic #4 explains how liquids can limit temperature range and reduce cycle life. Additionally, if high pressure is required, the liquid will limit scalability. The airtight bag can be easily sealed under vacuum to incorporate 1 atmosphere of pressure, but if there is liquid to flow, then adding high pressure evenly throughout the battery will be problematic. This is a scalability barrier that cannot be easily solved with solid-state electrolytes. During processing, the ceramic needs to be sintered and the sulfide requires huge pressure (500 bar), which is possible for the separator but not for the positive electrolyte. In contrast, solid polymers can work simultaneously as separators and catholytes only if their ionic conductivity is comparable to that of conventional liquid electrolytes. Summary: Whether we call it solid, semi-solid, or hybrid, using any liquid electrolyte introduces the risk of thermal runaway, limits the temperature range, and inhibits scalability through high voltages.
Temperature range – is it clear enough? Solid-state batteries should offer higher temperature adaptability than liquid electrolyte batteries, that is, without the need for cooling systems. Liquid electrolyte becomes unstable above 40°C and accelerates the degradation of the positive electrode. If semi-solid or hybrid batteries require cooling systems, this will impact energy density and cost. A simple way to check is to test whether the data covers the range of 40°C to 80°C. 80°C is a useful benchmark because it is above surface temperatures on the hottest days. This means an electric car can be parked in the sun without draining the battery’s cooling system! Please check the data carefully, sometimes the high temperature statement may not include the entire battery for the separator electrolyte. Some solid polymer electrolytes have the opposite problem in that they must be heated before the ions can conduct electricity, usually between 50-80°C. This would also increase cost, reduce the energy density of the system, and be impractical for general use. Summary: Solid-state batteries should operate over a wide temperature range without the need for external systems that would otherwise be recognized in energy density and cost claims.
Lithium compatibility and dendrites in order to increase energy density, the electrolyte needs to work stably with lithium metal and high-energy cathode, otherwise the energy density improvement will be minimal. Developers of various solid-state batteries have experimented with lithium metal and then moved to graphite or silicon. This indicates incompatibility with lithium metal, although one company claims that lithium metal is unsafe, which could also be interpreted as being incompatible with their solid electrolytes. Another unresolved debate is the best solution to who owns the dendrites. Ceramics and sulfides are very hard, but have grain boundaries and are prone to brittleness. Polymers have been accused of being too weak, but some companies disagree. Cycle life and millions of tests will provide the answer, but as mentioned above, failure is statistically inevitable, so the debate once again turns to how to eliminate the possibility of thermal runaway. Summary: Highly stable and mechanically strong solid-state electrolytes are needed to increase energy density.
Layer Thickness – Often Not Mentioned High energy density requires a thin separator equivalent to current li ion customized battery packs, an even thinner anode, and a cathode at least as thick as current li ion customized battery packs. Taking actual numbers as an example: the separator is in the 20-30µm range, thin lithium is less than 40µm, and the cathode is at least 80µm. Why? If not, simple math proves that batteries can’t achieve higher energy densities. There are some innovative 3D technologies that developers may disagree with, but they also need to respond to scalability and processability issues (see Topic #10). Reasons why layer thickness is often not mentioned include that thin ceramic separators are very fragile, reducing thickness makes it difficult to extend the cycle life of lithium, and penetration of thick cathodes through solid electrolytes is often difficult, often requiring liquid. Summary: Higher energy density requires a thinner negative electrode and a thin separator to match the thick positive electrode.
Cycle Life and C-Rate – Battery Performance For many developers and original equipment manufacturers (OEMs), long battery life and fast charging are top topics as it promises longer range and shorter battery life for electric vehicles. parking time. It’s what everyone wants to hear and therefore becomes the target of propaganda. Long cycle life and high C rate can be achieved, but usually at the expense of each other, which is often not explained in detail. As mentioned above, layer thickness or pressure requirements may not be stated. Most readers have come to understand that, typically, long cycle life is typically achieved at low C rates, while high C rates often come at the expense of cycle life. Sometimes the fine print terms will qualify long life with a high C rate in cycles 1-10 or 1-30, while other cycles will go in with a low C rate. Solid-state batteries should eventually offer really long life and fast charging. One reason is the ability to operate stably at higher temperatures, thus accommodating faster power transfer, but this requires a highly stable solid-state electrolyte in the battery. Another reason is that charging speed is limited by the rate of intercalation reactions, a limitation that is eliminated when using lithium metal. Summary: Dramatic cycle life and C rates are closely publicized but are often opaque and further distract from the fact that the actual fundamentals are not achieved.
Risks introduced the primary goal is to improve safety, but some “solutions” reduce one risk and then increase another. It is important to remember that failures and accidents are inevitable, so we need to check whether the failure mode is “fail-safe” or not. Adding huge amounts of pressure means containing an unexpected release of energy. The use of certain liquid electrolytes retains the risk of thermal runaway. At least one company claims that using lithium metal is dangerous, but using ultra-thin lithium could mitigate this risk. Using sulfide introduces new hydrogen sulfide risks due to moisture sensitivity. Summary: The key to reducing risk is to have a highly stable solid electrolyte throughout the battery, allowing it to operate over a wide temperature range.
Packaging and Demonstration Cells Packaging has already been mentioned regarding pressure (Topic #2) and requires further analysis as this is one of the most opaque issues. Gorgeous pictures of giant display batteries have one thing in common – a real operating system that requires pressure, cooling, heating or contains risks such as hydrogen sulfide is never shown. Or, there are animations that show certain obvious advantages, but don’t show the whole story. Or there are some very realistic pictures without any mention that they are renderings.
Scalable Process – Tiny Wearables and Cost Every startup has an obligation to say “our technology is easily scalable”. Without specific figures and timetable, this statement is somewhat empty. Some companies have developed solid-state battery technology for the tiny wearables market, and then implicitly scalable it for the electric vehicle and renewable energy markets. Most tiny solid-state batteries are made of ceramic, but this is not easily scalable. Novel architectures and processes, such as 3D or printing, should not be put in the same context as JICA-scale lithium-ion batteries that took decades to develop. Solid-state batteries need to reduce costs to make electric vehicles and renewable energy affordable. New processes will not reduce costs until they have been developed for a decade. Adding external systems does not reduce costs. Ceramics need to be sintered. Sulfide requires large-scale pressure during its production. Hybrid batteries require “special protective coatings” to reduce risk. All of this adds to costs. The goal is to reduce costs. Processing should use standard R2R processes. It is widely accepted that solid polymer electrolytes are the simplest to manufacture and easiest to adapt to existing processes and cell structures. Summary: The standard R2R process combined with fewer product materials (no active separator, no cathode host, no liquid) provides cost reduction incentives. Summary Solid-state technology has made tremendous advances that will ultimately provide improved safety and higher performance at lower cost. But solid-state battery developers need to openly address these issues to launch viable products for the real world. Reduce risk, eliminate the need for external pressure systems, increase energy density and use existing R2R production to produce commercial-scale batteries. While there’s still a lot of work to be done, and of course I’m biased, I think Nuvvon is the only solid-state battery technology provider to date that can do it all.
Nuvvon:
Completely solid state, therefore reducing the risk of thermal runaway
Operates without external pressure system
Solid polymer as separator electrolyte and positive electrolyte – no liquid or gel particles
Wide temperature range (currently -10 to +80°C)
Compatible with thin lithium and has high mechanical strength to resist dendrites
The cycle life and C rate of thin lithium at C/4 are still a work in progress, with cycle life in the range of several hundred cycles
No new risks (no pressure, no liquids, no harmful ingredients)
Bare cells operate without external systems (pressure, heating, cooling)
Pouch cells using existing battery architecture and built on standard li ion customized battery packs processes.
Author Dr. Simon Madgwick of Nuvvon Inchttps://www.batterydesign.net
If you have any question, please feel free to contact us:
Name: Dawn Zeng (Director)
E-mail address: sales@himaxelectronics.com
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Current li ion customized battery packs, which use graphite anodes, liquid electrolytes, and cathode materials such as NMC and LFP, are generally considered to be approaching their performance limits. However, there are still ways to further improve performance and reduce costs, from battery pack materials to battery pack design.
Moving from graphite to silicon
Silicon anodes offer an exciting alternative that can significantly increase energy density and performance. Although silicon materials have only been used in negative electrodes at a weight ratio of less than 5% in the past, it has been difficult to go beyond its use as an additive due to its inherent volume expansion and the resulting stability and cycle life issues. However, silicon anode technology has continued to improve over the past 10-15 years, allowing batteries to use 5-100% silicon in the anode.
It’s exciting to see silicon anode technology continue to evolve in 2022, including Nexeon raising $200 million in funding and licensing materials to SKC, Amprius deciding to go public, Group14 Technologies raising $400 million, and POSCO Holdings acquiring Tera Technos. In addition, Amprius has delivered 450Wh/kg commercial batteries for satellites, while the Whoop 4.0 fitness wearable device released in September 2021 uses Sila Nano’s silicon anode technology. Taken together, these developments indicate that the silicon anode market is increasingly maturing, and the adoption of advanced silicon anode materials in a variety of applications is becoming increasingly possible. As a result, IDTechEx predicts that the adoption of silicon anode materials will grow significantly, although graphite is expected to remain dominant until the 2030s.
New method of cathode synthesis
Future li ion customized battery packs may use a similar set of cathode materials that are commercially available today. LNMOs or LFP-related LMFPs may be considered exceptions, although neither of them offer improvements in energy density but offer different trade-offs between high performance and low cost. Lithium-rich manganese-based cathodes may offer modest increases in energy density, but commercial development has been limited and slow. Improvements in cathode materials will generally be incremental. Instead, the biggest changes in cathode technology and innovation may come from how they are synthesized. Current synthesis techniques require higher temperatures and relatively long times (days) while using large amounts of reagents and water, resulting in high production costs and environmental impact. Nano One Materials and 6K Energy (part of 6K Inc) are two companies aiming to commercialize new cathode material synthesis methods.
Nano One Materials uses a solution-based “one-pot” process to produce coated cathode materials. The company partnered with cathode manufacturer Pulead and reached a development agreement with BASF in early 2022. 6K Energy uses microwave plasma reactors to produce their cathode materials, and they can also synthesize silicon anode and solid electrolyte materials. 6K Inc completed a $102 million Series D round in May 2022 and struck a development deal with lithium producer Albemarle and fellow cathode startup Our Next Energy. Nano One Materials and 6K Energy both promise to provide streamlined production processes to increase capacity, yield and reduce production costs while reducing environmental impact.
Solid electrolytes and new electrolyte formulations
While solid electrolytes attract a lot of attention in electrolyte technology, the use of new additives and electrolyte formulations can continue to provide incremental improvements to liquid electrolyte systems. For example, New Dominion Enterprises is developing electrolyte additives and solvents based on phosphorus nitrogen compounds to help improve safety and performance. Specifically, their electrolyte additive materials can increase thermal stability, reduce vapor pressure, and improve solid electrolyte/electrode interface (SEI) formation. Longer term, the company aims to completely replace traditional organic solvents with their electrolyte system, potentially significantly improving safety.
However, the holy grail of battery technology for many electric car makers remains solid-state batteries, which can significantly improve safety by replacing the flammable liquid electrolytes currently used with solid electrolytes. In addition, solid-state electrolytes also offer the potential for the use of lithium metal anodes, which can push energy density to more than 1000 Wh/l. The solid-state battery market is expected to grow to more than $8 billion by 2031, and liquid electrolytes will remain an important part of the market. Challenges regarding the stability, cycle life, manufacturability, and even safety of solid-state electrolyte systems mean that competition between different electrolyte systems continues.
Space efficient battery pack
Particularly for electric vehicles, battery pack design provides another key avenue for enhanced performance. Many automotive companies have announced the adoption of battery cell assembly designs to eliminate materials associated with module housings and optimize packaging efficiency, ultimately increasing energy density and improving battery integration into vehicles. BYD advertises that it can increase volume utilization by 40% to 60% in this way, while battery manufacturer CATL announced that their latest battery cell assembly design can achieve a volume utilization of 72%. Back in early 2022, CATL announced that their LFP battery packs could reach 160 Wh/kg and 290 Wh/l, which started to compete with their NMC rivals. Maximizing energy density helps alleviate the major shortcomings of cheaper LFP batteries, providing a way to create cheaper batteries with longer range. The disadvantage of these types of battery designs is reduced serviceability, which may limit their use in commercial vehicles.
Smarter battery management system
Improvements in battery management systems (BMS) can provide a way to improve many aspects of battery performance without facing the challenges of materials development. For example, Qnovo emphasizes that their BMS software and analytics can simultaneously improve safety, cycle life, charging time and battery usable capacity. The company uses a combination of battery usage data and battery impedance measurements to develop physical models of li ion customized battery packs, which are then used to optimize operating and charging protocols. Another use case for their BMS solution could stem from battery failure detection, which could be extremely valuable given recent electric vehicle recalls.
Outside the field of electric vehicles, improved BMS will also be very valuable for other end applications, such as smartphones or power tools. OnePlus 10T’s advertised 1-100% charging in 19 minutes is partly achieved by a smarter charging algorithm and more efficient thermal management. In addition to fast charging capabilities, OnePlus also advertises a life of 1,600 charge and discharge cycles, which is beyond the cycle life typically advertised for LCO and consumer electronics batteries. While battery development often involves trade-offs between key performance characteristics such as energy density, cycle life, fast charging and safety, improvements to the BMS can feasibly provide improvements in all of these performance characteristics.
Ultimately, there are many avenues to improve battery performance and reduce costs, including various others not discussed here. While some developments may provide only incremental benefits, their combination will allow li ion customized battery packs performance to continue its steady advance.
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Custom lithium battery pack innovation is not easy.
In the past decade or so, Custom lithium battery pack industrialization has developed rapidly and production capacity has increased by leaps and bounds. However, there have been few revolutionary breakthroughs in lithium battery technology.
In terms of material system, lithium iron phosphate and ternary are still dominant; in terms of structural system, square, cylindrical and soft packages are still dominant.
In the final analysis, there are many constraints on lithium battery innovation, and factors such as cost, safety, energy density, cycle times, temperature performance and even resource security need to be taken into consideration at the same time.
In the context of difficult innovation, the lithium battery industry has also carried out various explorations in recent years, including cobalt-free, high-nickel, solid-state, composite current collectors, lithium iron manganese phosphate and even sodium-ion batteries that are free of lithium resources in terms of material systems. Short knives, blades, 4680 large cylinders, and high-speed lamination from manufacturing process angles, etc.
Regarding the mature material system and structural system, from the perspective of industrialization, penetration rate and industrial impact, among the technological innovations in recent years, which technical route is more prominent? Who can be called the second technical line?
This is a topic worth taking stock of.
What is The second technical route?
Comprehensive comparison shows that lamination technology innovation is more prominent.
The lamination process has the characteristics of higher energy density, more stable internal structure, longer cycle life, and safer. It is not only very suitable for long and thin battery cells, but also has a higher degree of compatibility with large-capacity battery cells.
The winding process that once dominated the mainstream has many bending areas and current collector welding areas, low internal space utilization, and uneven winding tension and deformation, especially in long thin and large capacity applications. The disadvantages are more obvious under the trend.
In recent years, Honeycomb Energy has taken the lead in applying lamination technology to square batteries, replacing the winding process and solving the problem of low efficiency of traditional lamination equipment. High-speed lamination technology has been continuously iterated for 3 generations, with efficiency and yield rates continuously improving, and costs increasing. The “flying stack” speed of the third-generation technology has reached 0.125 seconds/piece, achieving the same efficiency as the winding process.
Lamination technology has also encountered a “historic opportunity”. With the rapid development of power batteries and energy storage batteries, the requirements for prismatic batteries and blade batteries are constantly increasing. The advantages of lamination technology in supporting and promoting the innovation of prismatic batteries and blade batteries are also increasing. It’s becoming more and more obvious.
As a leader and staunch supporter of lamination technology, Honeycomb Energy has fully adopted lamination technology since the company was founded. As of the end of 2022, the production capacity of the lamination process has reached 15.6GWh, and it is mainly high-speed lamination. It will continue to expand with the implementation of planned production capacity.
Nowadays, lamination technology is accelerating its promotion and fully penetrated.
At present, the leading lithium battery companies have adopted lamination technology to varying degrees and have all entered the market. Especially in large-capacity square, blade and soft-pack batteries, lamination technology has become a trend or even a must.
Judging from the results, compared with other technological innovations in recent years, the innovative iteration and industrialization effect of lamination technology are more prominent. Leading companies have made plans one after another, and the penetration rate continues to increase.
Custom lithium battery pack innovation is “blooming”. From the perspective of industrialization and penetration, the lamination technology that is constantly iterating in process innovation has opened up a new world beyond traditional winding technology and has become the well-deserved “second technology route” of lithium battery. .
The platform effect of stacking technology is prominent
Stack technology is more like a process platform.
On this platform, it is compatible with different material systems such as ternary, lithium iron phosphate and even solid-state batteries and semi-solid batteries, as well as different structural systems such as square, blade and soft pack.
Therefore, lamination technology has a strong industrial amplification effect and is of great value in promoting the technological progress and industrial development of the lithium battery industry.
Especially in the blade battery, it can be said to be a “perfect match” and “mutual achievement” with the lamination technology. Without the lamination technology, it would be difficult for the “long and thin” blade battery to shine. After all, the winding technology has “winding technology”. “around” the limit.
The same is true not only for blade batteries, but also for prismatic batteries, especially larger models. With the development of the energy storage industry, prismatic batteries continue to “expand”, from the previously popular 280Ah to today’s 300Ah+, lamination technology can support the larger size of prismatic batteries.
For soft-pack batteries, lamination technology is a natural “perfect match” and can bring greater packaging advantages, especially when combined with emerging semi-solid-state batteries and solid-state batteries, the advantages are even more obvious.
Lamination technology has stimulated innovation at the cell level in large-capacity prismatic batteries, blade batteries, and soft-pack batteries. It is also very helpful in promoting innovation in battery packs. Even CTP and CTC can achieve better integration effects at the system level.
As a platform technology, lamination technology has brought lithium battery structural innovation to a new level, inspiring innovation at the prismatic battery, blade battery, pouch battery and even battery system level, leading the innovation of a new generation of lithium battery technology, with huge flexibility, the industry has far-reaching impact.
If you have any question, please feel free to contact us:
Name: Dawn Zeng (Director)
E-mail address: sales@himaxelectronics.com
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In the manufacturing process of li ion customized battery packs, there are three very critical items that must be strictly controlled: first, dust; second, metal particles; and third, moisture.
Failure to control dust and metal particles will directly lead to safety accidents such as internal short circuits and fires in the battery; and if moisture is not effectively controlled, it will also cause great harm to battery performance and lead to serious quality accidents!
Therefore, it is very critical to control the water content of main materials such as pole pieces, diaphragms, and electrolytes in the manufacturing process. We must not relax at all and must always work hard!
The following is a detailed explanation from three aspects: the harm of moisture to lithium batteries, the source of moisture in the manufacturing process, and the control of moisture in the manufacturing process.
The harm of moisture to li ion customized battery packs
Battery bulges and leaks
If there is too much moisture in the lithium-ion battery, it will react chemically with the lithium salt in the electrolyte to generate HF:
H2O + LiPF6 → POF3 + LiF + 2HF
Hydrofluoric acid (HF) is a very corrosive acid that is very destructive to battery performance:
HF will corrode the metal parts, battery casing, and seals inside the battery, causing the battery to eventually break and leak.
HF will destroy the SEI film (Solid-Electrolyte-Interface in English) inside the battery and will react with the main components of the SEI film:
ROCO2Li + HF → ROCO2H + LiF
Li2CO3 + 2HF → H2CO3 + 2LiF
Finally, LiF precipitates inside the battery, causing lithium ions to undergo an irreversible chemical reaction on the negative electrode of the battery, consuming active lithium ions and reducing the energy of the battery.
When there is enough water, a lot of gas will be produced, and the pressure inside the battery will increase, causing the battery to deform due to stress, leading to dangers such as battery swelling and leakage.
Most of the bulging batteries and open covers of mobile phones or digital electronic products encountered during use on the market are caused by high moisture inside the lithium battery and gas production.
The internal resistance of the li ion customized battery packs increases
The internal resistance of the battery is one of the most important performance parameters of the battery. It is the main indicator of the difficulty of transmitting ions and electrons inside the battery, and directly affects the cycle life and operating status of the battery. The smaller the internal resistance, the better the battery is when it is discharged. The less voltage it takes up, the more energy it outputs.
When the water content increases, POF3 and LiF will precipitate on the surface of the battery’s SEI membrane (Solid-Electrolyte-Interface), destroying the density and uniformity of the SEI membrane, causing the internal resistance of the battery to gradually increase., the battery’s discharge capacity continues to decrease.
Reduced cycle life
Excessive water content destroys the SEI film of the battery, the internal resistance gradually increases, the discharge capacity of the battery becomes smaller and smaller, the battery usage time becomes shorter and shorter after each full charge, and the number of charges and discharges that the battery can be used normally (Cycles) will naturally become less, and the battery life (life) will also be shortened.
If you have any question, please feel free to contact us:
Name: Dawn Zeng (Director)
E-mail address: sales@himaxelectronics.com
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