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Lithium Iron Phosphate Vs Lithium Cobalt Oxide

Li-ion-Vs-Lifepo4

Li-ion-Vs-Lifepo4

Lithium Cobalt Oxide batteries and lithium iron phosphate batteries are the most widely used formulas for both LiPo (Lithium Polymer) and Li-Ion (Lithium Ion).

What difference between Lithium Iron Phosphate and Lithium Cobalt Oxide? This video will help you to know that.

The cycle life of Lithium Iron Phosphate batteries are more than 4 to 5 times that of Lithium Cobalt Oxide batteries, and is safer; however, its disadvantage is the lower discharge platform and energy density. The nominal voltage of Lithium Iron Phosphate is 3.2V, the full voltage is 3.65V, but the nominal voltage of Lithium Cobalt Oxide battery is 3.7V, and the full voltage is 4.2V.

The difference between 3.2V and 3.7V may not seem like much, but when we connect cells in series to make a 12V battery pack, only 3 cells are needed for Lithium Cobalt Oxide cells and 4 cells for Lithium Iron Phosphate cells, which makes a difference in cost and weight.

In addition, these two types of batteries are quite different in terms of cycle life, energy density, and safety performance.

The Energy Density

The energy density of Lithium Cobalt Oxide is higher than that of Lithium Iron Phosphate resulting in better Watt-hours Wh/kg and Watt-hours Wh/Liter.

A Lithium Cobalt Oxide battery (LCO) is a type of rechargeable battery, combined with a microporous separator with electrolyte, it mainly relies on the movement of lithium ions between positive electrode and negative electrode. Lithium batteries use an intercalated lithium compound as an electrode material.

A Lithium Iron Phosphate battery (LiFePO4) is a type of LiPo battery that uses Lithium Iron Phosphate as the anode material and a graphite carbon based electrode with a metallic backing as the cathode. It has a wide range of raw material sources, a long cycle life, a high safety index, excellent thermal, chemical stability, and outstanding high temperature resistance.

The Cycle Life

In terms of cycle life, Lithium Cobalt Oxide generally can reach 500 cycles, and the cycle times of Lithium Iron Phosphate are longer. This is a major feature of Lithium Iron Phosphate batteries, which can reach 1500 to 2000 cycles or more. The Lithium Iron Phosphate battery can also reach 100% depth of discharge. Therefore, a good Lithium Iron Phosphate battery can last from 3 to 7 years under regulated use.

The Safety Performance

In terms of safety, Lithium Iron Phosphate batteries are far safer than Lithium Cobalt Oxide batteries.

Lithium Cobalt Oxide batteries have the advantage of high current charging and discharging, and they allow devices to release more energy in a short period of time. Lithium Cobalt Oxide with high discharge rates can achieve continuous discharge rates of up to 50C and pulse discharge rates of up to 150C. They are 40% lighter than a steel-cased lithium-ion battery of the same capacity and 20% lighter than an aluminum-cased battery. These make them more useful for racing applications and power tools, such as RC models and UAVs.

Generally speaking, Lithium Iron Phosphate batteries are not capable of high current discharge, as they are mostly used in energy storage applications, like UPS and solar energy storage systems. But Grepow’s Lithium Iron Phosphate batteries can be discharged at a high rate, with a continuous current of up to 40C, which is suitable for applications such as boat racing, jump starters and powersports.

Shaped Battery

LiPo batteries can be made into a variety of shapes, and are well suited for watches, headphones, rings and other devices that require a high degree of form. However, the voltage and energy density of Lithium Iron Phosphate batteries are lower than those of other Lithium Cobalt Oxide batteries.

 

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UK’s Largest Battery Storage Project At 640MWh Gets Go Ahead From Government

A render if what the DP World London Gateway project will look like when completely constructed, based on Fluence’s sixth-generation Gridstack system design. Image: InterGen.

The Department of Business, Energy and Industrial Strategy (BEIS) in the UK has given the green light to the country’s biggest ever battery storage project.

InterGen has gained planning permission for a 320MW / 640MWh lithium-ion battery site at DP World London Gateway, a new port and logistics centre on the Thames Estuary in Essex, south-east England. The £200 million (US$267 million) project will also have the potential for further expanding, as far as 1.3GWh.

Fluence is providing the technology for the site, having worked in partnership with InterGen for the past two years following a competitive tender process. The companies initially signed an exclusivity agreement for another project at Spalding, which was since been extended to the Gateway project.

According to the company, this puts it at 10 times the size of the largest battery currently operating in the UK. Indeed it will dwarf the UK’s biggest active project so far, the 50MW / 75MWh Thurcroft battery storage site in South Yorkshire, which was recently acquired by stock exchange listed specialist fund Gresham House Energy Storage.

In terms of international context, the world’s largest battery project already under development is Vistra Energy’s Moss Landing project in California, which is permitted for an eventual 400MW / 1,600MWh, to be built in phases. The world’s largest project in operation today is the Gateway project developed by LS Power, also in California. That project is currently at 230MW output and 230MWh capacity, as of August, with a futher expansion to 250MW / 250MWh already underway. Australian utility AGL recently said it is planning a 250MW battery storage project with up to 1,000MWh of capacity, while The Red Sea Development Company, developing a huge luxury resort in Saudi Arabia said last week that it plans to use 1,000MWh of battery storage to integrate local renewable energy resources.

With the share of renewables continuing to grow, the need to balance the grid through the use of technologies such as storage is continuing to grow alongside it. As such, InterGen’s battery – which is set to be used to support and stabilise existing electricity supplies – will represent a major piece of the system architecture.

Image: InterGen.

InterGen CEO Jim Lightfoot said the company was “delighted” to be granted consent for the Gateway project, as its mission was to deliver the “flexible electricity solutions” needed for a low carbon world.

“We are excited to be entering a new phase in our growth as an organisation, and will continue to explore opportunities to develop projects which can support the energy transition.”

Till recently, large scale energy storage projects were not possible in the UK, as planning legislation limited storage project to 50MW in England and 350MW in Wales. These were relaxed in July, to help increase flexibility.

InterGen’s storage project will become one of the largest in the world, topping the biggest single-site battery project currently, a 250MW site switched on in August in California by its developer, infrastructure company LS Power.

Construction of the DP Word London Gateway is expected to get under way in 2022, and the battery to become operational in 2024.

Additionally, InterGen is looking to develop another large scale battery project at its site in Spalding, Lincolnshire. This would be a 175MW / 350MWh site, and planning permission is already in place.

The Edinburgh-headquartered independent energy generator currently supplies around 5% of the UK’s generating capacity, with natural gas sites in Coryton in Essex (800MW), Spalding in Lincolnshire (1,250MW) and Rocksavage in Cheshire (810MW).

A version of this story for local audiences was first published on Solar Power Portal. 

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Best LiFePO4 Battery For RV Application

RV-Battery

RV-Battery

Low-Temperature LiFePO4 Battery: Why It’s Best For RV

Like humans, batteries could function their best at room temperature. Low-temperature batteries like Lithium Iron Phosphate, like the LifePO4 Battery manufactured by Himax, could be useful for RVs. These good batteries can work well in a temperature range of about –40℃ to 50℃. That’s why these batteries are ideal for RV application because these are specially-made, low-temperature batteries that are ideal for longer use in, particularly cold environments.

Perhaps you want to know deeper about what LiFePO4 Battery has to offer. In this article, you will understand how the low-temperature LifePO4 batteries work, and why it is ideal for any RVs. You will also know its features to help you understand this product.

Benefits of Using Low-Temperature LiFePO4 Batteries 

When it comes to powering your RV, perhaps you want to consider Grepow’s Low-temperature LiFePO4 Batteries. Here are the benefits when you opt to use these kinds of batteries.

  • LiFePO4 batteries are safer and even more practical for low-temperature
  • It can be charged at temperature down to 0℃
  • It features proprietary technology which draws excellent power from the charger itself
  • The process of charging and heating is seamless for users
  • Internal heating and monitoring system are easy to process
  • Environmentally friendly and proven safe for use in any system
  • Customizable (Voltage, Capacity, Size, BMS)
  • Provides your RV a high energy density
  • The cycle life could reach thousands of cycles

LiFePO4 battery Features 

Understanding your battery’s features is essential to know if it’s compatible with your RV. Check out the Himax’s Low-Temperature LiFePO4 features to know how it delivers more power and longer life.

Himax LifePO4 battery 0.2C discharge at -20 to -40 degree temperature
  • Very good temperature resistance; the range of operating temperature is from -40℃to 50℃.
  • The discharge current at 0.2C is over 85% of initial capacity at -20℃, 85% at -30℃, around 55% at -40℃.
  • Has a higher capacity than other similar-sized lead-acid batteries.
  • A good drop-in replacement for lead-acid batteries
  • It comes with a longer life cycle compared to other lithium-ion batteries.
  • Can reach up to 2000 times life cycle

LiFePO4 battery Applications

One good thing about the Himax’s LiFePO4 battery is that it can be used or applied to various equipment. It’s widely used in fields that require low-temperature applications like:

  • Medical Equipment
  • Drones/UAVs
  • Remote Controls for Passion and Hobbies
  • Industrial Applications
  • Powersports
  • Energy Storage (Home Solar, Outdoor, Marine)

Conclusion

Having a reliable and best battery for RV applications like Himax’s LiFePO4 Batteries can give you the best RV experience. Now that you know its benefits and features, perhaps you will consider the LiFePO4 battery from Grepow because it’s not only reliable but it’s also very helpful to maintain your RVs longevity.

Hopefully, you could understand the features and how low-temperature batteries work for your RV. Don’t hesitate to get something like Himax low-temperature batteries; always use your units and equipment with confidence because you know that batteries could withstand low-temperature applications.

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Best LiFePO4 Battery For RV Application

Lithium cell

Lithium cell

Low-Temperature LiFePO4 Battery: Why It’s Best For RV

Like humans, batteries could function their best at room temperature. Low-temperature batteries like Lithium Iron Phosphate, like the LifePO4 Battery manufactured by Grepow, could be useful for RVs. These good batteries can work well in a temperature range of about –40℃ to 50℃. That’s why these batteries are ideal for RV application because these are specially-made, low-temperature batteries that are ideal for longer use in, particularly cold environments.

Perhaps you want to know deeper about what LiFePO4 Battery has to offer. In this article, you will understand how the low-temperature LifePO4 batteries work, and why it is ideal for any RVs. You will also know its features to help you understand this product.

lifepo4-battery-12v

Benefits of Using Low-Temperature LiFePO4 Batteries 

When it comes to powering your RV, perhaps you want to consider Grepow’s Low-temperature LiFePO4 Batteries. Here are the benefits when you opt to use these kinds of batteries.

  • LiFePO4 batteries are safer and even more practical for low-temperature
  • It can be charged at temperature down to 0℃
  • It features proprietary technology which draws excellent power from the charger itself
  • The process of charging and heating is seamless for users
  • Internal heating and monitoring system are easy to process
  • Environmentally friendly and proven safe for use in any system
  • Customizable (Voltage, Capacity, Size, BMS)
  • Provides your RV a high energy density
  • The cycle life could reach thousands of cycles

LiFePO4 battery Features 

Understanding your battery’s features is essential to know if it’s compatible with your RV. Check out the Grepow’s Low-Temperature LiFePO4 features to know how it delivers more power and longer life.

0.2C discharge at -20 to -40 degree temperature

  • Very good temperature resistance; the range of operating temperature is from -40℃to 50℃.
  • The discharge current at 0.2C is over 85% of initial capacity at -20℃, 85% at -30℃, around 55% at -40℃.
  • Has a higher capacity than other similar-sized lead-acid batteries.
  • A good drop-in replacement for lead-acid batteries
  • It comes with a longer life cycle compared to other lithium-ion batteries.
  • Can reach up to 2000 times life cycle

LiFePO4 battery Applications

One good thing about the Grepow’s LiFePO4 battery is that it can be used or applied to various equipment. It’s widely used in fields that require low-temperature applications like:

  • Medical Equipment
  • Drones/UAVs
  • Remote Controls for Passion and Hobbies
  • Industrial Applications
  • Powersports
  • Energy Storage (Home Solar, Outdoor, Marine)

 

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What’s The Difference Between A BMS And PCM?

BMS-AND-PCM

Before we go straight into comparing these protection boards, let me help define these first.

Define the PCM, PCB and BMS

Generally speaking, battery protection boards can be divided into two types. We usually refer to them as the PCM (Protection circuit module) or otherwise known as the PCB (Protection circuit board), and the BMS (Battery management system).

A battery management system (BMS) or Protection Circuit Module (PCM) is one of the most important parts of a lithium battery. Without either one of these two components, a lithium battery could be very dangerous.

BMS-AND-PCM

The features of PCM

The PCM is mainly composed of hardware electronic components, and it protects the charging and discharging of the lithium battery pack. When the pack is fully charged, the PCM can ensure that the voltage difference between the single cells is less than the set value in order to achieve balanced voltages between the different cells. At the same time, the PCM will detect the over-voltage, under-voltage, over-current, short-circuit, and over-temperature status of every single cell in the battery pack to ultimately protect and extend the battery’s life.

BMS modules

The BMS, also called the battery manager, maintains the same features as a PCM and PCB but also has the ability to offer additional protection and features. It provides real-time monitoring of the battery and transmits data through software. The status information is given to the electrical equipment. The BMS itself includes a management system, a control module, a display module, a wireless communication module, and a collection module for collecting battery information of the battery pack, and others.

lectric shavers and power tool batteries are protected with PCM and PCB. Drones batteries, on the other hand, utilize a BMS. The drone operator will have the ability to check the battery level in real-time and calculate the remaining run time of the battery. This requires the battery to support these data transmissions, which can only be offered by a BMS.

Which solution is better for your project?

The PCM and PCB can only offer the basic levels of protection and are cheaper whereas the BMS includes all the functionalities of a PCM and PCB AND more (although the price tag increases as well). So, if you’re trying to decide between these boards, it’ll really depend on exactly what market your product will be geared towards. If you still can’t make a decision, feel free to reach out to us, and we’ll help you.

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Why Lithium Iron Phosphate Batteries Are The Best Way To Power Your Floor Machine

Floor-Machines-with-Lithium-Battery

Floor-Machines-with-Lithium-Battery

Lithium batteries are making their way into the Floor Cleaning market and for good reason. If you look at all of the benefits, they are hands-down the best solution to power your floor cleaning machines. Learn why below:

LIFE

Probably the most well-known and obvious benefit is significantly longer life. Lithium iron phosphate (LiFePO4) batteries will provide 5 – 10 times more cycles than lead-acid batteries. This means, you aren’t replacing your batteries every 2-4 years. And, replacing lead-acid batteries is not a fun task; first there is downtime to do the battery replacement, then there is the heavy lifting to remove old batteries and install new batteries. Finally, there is the disposal of the spent batteries.

PRODUCTIVITY

Another major benefit is the runtime or range. There are a few reasons LiFePO4 batteries can, and do, provide increased runtime over lead-acid batteries.

1. The main reason is that a lithium battery provides the full rated capacity, regardless of the rate of discharge. Lead-acid batteries are typically rated at the 5-hour or 20-hour rate, which are based on constant current, laboratory-tested, and low rates of discharge.

For example, a 200Ah (based on the 20-hr rate) lead-acid battery will provide 200Ah if it is run at a constant current of 10A for 20 hours. However, that same battery may provide only 135Ah if it is run at a constant current of 75A for 1.8 hours.

With lead-acid batteries, as the rate of discharge increases, not only does the runtime decrease but the overall size of the fuel tank decreases.

In a real application, the current is never constant, in fact, it varies continuously and often significantly. It is unpredictable. So with a lead-acid battery, you are never really getting the published battery capacity, in a floor machine.

With a lithium iron phosphate battery, the fuel tank remains the same size regardless of the state of discharge. A 200Ah battery will provide 200Ah whether it is discharged at 10A or 100A. The battery will always deliver its published capacity.

2. Another reason LiFePO4 batteries provide more runtime than lead-acid batteries, is the capacity degradation over the life of the battery is slow and minimal.

Traditional wet lead-acid batteries typically provide around 80% capacity when brand new. They work up to their full capacity and remain there for a couple hundred cycles and then decline over the next couple hundred cycles. AGM or Gel lead-acid batteries will provide their full capacity when brand new and steadily decline right away. Some Gel batteries will maintain their full capacity for a few hundred cycles but then rapidly decline.

Lithium iron phosphate batteries provide full rated capacity immediately and continue to do so for about 1000 cycles, with a slow decline to 80-90% capacity between 1000 to 2000 cycles.

3. Lithium batteries charge quickly and can be opportunely charged without damaging the battery. This can significantly extend the range of your LiFePO4 battery per shift.

Increased runtime, means increased productivity!

POWER

Lead-acid batteries provide full power for a relatively short period of time because the voltage declines steeply during usage. Lithium iron phosphate batteries provide full power throughout usage. This means, your floor cleaning equipment has full power throughout its shift.

CONVENIENCE

How convenient are lithium batteries? Very. No maintenance, no adding water, no cleaning acid residue from cables, connections, battery tops and equipment. No replacements, or at least not for many years, and easy installation due to being incredibly light compared to lead-acid batteries.

ROBUST

Lithium iron phosphate batteries are difficult to damage. They can’t be over-charged because the Battery Management System protects against that. Unlike lead-acid batteries, if they are under-charged or left in a partial state of charge, they will not be damaged.

SAFETY

Lithium iron phosphate batteries are safe. Not all lithium chemistries are the same. LiFePO4 are an inherently safe chemistry. They produce a fraction of the heat generated by other lithium chemistries, due to their structural stability. Not to mention, they eliminate exposure to harmful gases that are continuously vented from lead-acid batteries.

COST

Lithium iron phosphate batteries offer great savings compared to lead-acid, between 20-50%, when you consider the total cost of ownership. Although the upfront cost of lithium is higher, the areas of saving are numerous. Reduced maintenance, battery replacement, labor and charging costs all add up to substantial savings. The lifetime cost is less than lead-acid and we’ve done the math to prove it!

Do you have questions about Himax lithium batteries for floor machines? Contact us and one of our tech experts will be in touch.

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Energy Storage: Global Capacity Predicted To Surge By A Third Every Year In 2020s

Battery-Storage-Projects

Battery-Storage-Projects

EDF’S West Burton B battery storage project in Nottinghamshire, one of Europe’s largest battery storage projects | Credit: EDF

The consultancy predicts that US and China will drive global growth in cumulative energy storage capacity, which should top 740GWh by the end of the decade

Energy storage is poised for a decade-defining boom, with capacity set to grow by almost a third worldwide every year in the 2020s to reach around 741GWh by 2030, according to analyst Wood Mackenzie.

The firm’s latest forecasts for the burgeoning sector released on Wednesday point to a 31 per cent compound annual growth rate in energy storage capacity in the 2020s.

Growth will be concentrated in the US, which will make up just under half of global cumulative capacity by 2030, at 365GWh, the analysis predicts, while front-of-the-meter (FTM) energy storage will continue to dominate annual deployments, accounting for around 70 per cent of global capacity additions to the end of the decade.

The US FTM market is set to surge through 2021 due to significant short-term resources planned before slowing slightly through 2025. Beyond 2025, growth will become steadier as wholesale market revenue streams grow and utility investment is normalised, the report adds.

In particular, utility resource planning in the US is set to take a front seat for deployments over the coming decade, it says, in line with major recent shifts in utility approaches to renewables and storage, with the majority of utilities dramatically shifting planned resources towards renewables and storage due to cost and state-driven clean-energy goals.

“We note a 17 per cent decrease in deployments in 2020, 2GWh less than our pre-coronavirus outlook,” said the consultancy’s principal analyst Rory McCarthy. “We expect wavering growth in the early 2020s, but growth will likely accelerate in the late 2020s, to enable increased variable renewable penetration and the power market transition.”

Just behind the US in energy storage deployment, China is expected to see exponential growth in storage capacity, accounting for just over a fifth of global cumulative capacity at 153GW by 2030, according to Wood Mackenzie.

Europe’s growth story, on the other hand, is expected to be slower than its global counterparts, with the UK and Germany continuing to dominate the continent’s FTM market out to 2025, with the markets in France and Italy also opening up.

Wood Mackenzie senior analyst Le Xu emphasized that “storage holds the key to strong renewables growth.”

“The question is whether storage can capture stable long-term revenue streams,” she added. “Low-cost and longer duration storage can increasingly out-compete coal, gas and pumped hydro, enabling higher levels of solar and wind penetration. However, most lithium-ion energy storage systems economically max out at 4 to 6 hours, leaving a gap in the market.”

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An Introduction On LiFePO4 Batteries

Parallel-Assembly-12v-Battery

Parallel-Assembly-12v-Battery

Lithium iron phosphate(LiFePo4) batteries are continually sought after in the battery market for their long life and safety. This is seen recently with Tesla’s Model 3 and BYD’s Han series launching with LiFePO4 batteries.

We will explore these pros and cons of LiFeP04 batteries in this article.

Table of Contents

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China’s CATL Poised To Overtake LG Chem As Top EV Battery Maker

EV-Battery-3.2v-100ah-200ah-280ah

EV-Battery-3.2v-100ah-200ah-280ah

Global competition for the world’s top spot for the manufacture of rechargeable batteries is getting fiercer as China is stepping up efforts to overtake its South Korean rival in the fast-growing electric vehicle market, Koreainvestors.com reports.

According to market research firm SNE Research on Oct. 5, South Korea’s LG Chem Ltd. maintained its market lead with 15.92 GWh of battery capacity supply in the first eight months of this year, accounting for 24.6% of the global EV battery market.

China’s Contemporary Amperex Technology Co. (CATL) came in second with 15.54 GWh, or 24% of the global market, followed by Japan’s Panasonic, whose market share stood at 19.2%.

Korea’s two other EV battery makers — Samsung SDI Co. and SK Innovation Co. — ranked fourth and sixth with 6.3% and 4.2%, respectively.

Data showed China’s CATL is swiftly closing in on market leader LG Chem. In July, LG Chem’s market share was 1.3 percentage points higher than CATL’s.

“LG Chem was able to keep its market leader position in the first half as the Chinese EV market shrank due to the coronavirus pandemic. But with the gradual recovery of the Chinese market since July, China’s battery makers are quickly narrowing the gap with their Korean rivals,” said a battery industry official.

Electric vehicles sold in China reached 83,000 units in August, more than half the global EV sales of 163,000 units.

China’s CATL poised to lead global market

CATL, which takes up 50-60% of the Chinese battery market, aims to expand its presence in Europe by building a plant in Germany and forging a partnership with Daimler AG.

Analysts said Chinese EV battery makers, on the back of strong government support, could overtake their Korean rivals in the near future. The Chinese government recently announced that it will extend state subsidies to its battery makers until the end of 2022. Such subsidies were scheduled to be phased out by the end of 2020.

Energy market researcher BloombergNEF predicts Chinese manufacturers will take the top spot in the global supply of EV batteries by the end of this year, leaving their Korean and Japanese rivals behind.

Korean companies are also facing competition from smaller rivals in Europe, where the growing EV market has helped LG Chem and other Korean battery makers gain ground in the global market.

Crowded EV battery market

According to foreign media reports, Northvolt AB, a Swedish battery developer and manufacturer, recently raised 600 million euros (820 billion won) in investment funding, in which German automaker Volkswagen also participated.

With the raised funds, Northvolt is known to be expanding its annual battery production capacity in Europe to 150 GWh by 2030.

Electric vehicle makers are also joining the race.

At its annual Battery Day on Sept. 22, Tesla Chief Executive Elon Musk said the company will make next-generation batteries for its electric cars in-house to cut costs.

The company said its battery production will rise to 100 GWh a year by 2022, similar to LG Chem’s annual output capacity for this year.

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Why Can’t The Maximum Voltage Of A Lithium-ion Battery Exceed 4.2V?

Lithium-Ion-Battery

The voltage of a lithium-ion battery is determined by the electrode potential. Voltage, also known as potential difference or potential difference, is a physical quantity that measures the energy difference of electric charges in an electrostatic field due to different potentials. The electrode potential of lithium-ion batteries is about 3V, and the voltage of lithium-ion batteries varies with different materials.

For example, a general lithium-ion battery has a nominal voltage of 3.7V and a full-charge voltage of 4.2V; a lithium iron phosphate battery has a nominal voltage of 3.2V and a full-charge voltage of 3.65V. In other words, the potential difference between the positive electrode and the negative electrode of a lithium-ion battery in practical use cannot exceed 4.2V, which is a requirement based on material and use safety.

Lithium-Ion-Battery

If the Li/Li+ electrode is used as the reference potential, μA is the relative electrochemical potential of the negative electrode material, μC is the relative electrochemical potential of the positive electrode material, and Eg, the electrolyte potential range, is the difference between the lowest electron unoccupied energy level and the highest electron occupied energy level. So the maximum voltage of the lithium-ion battery is determined by μA、μC、Eg.

The difference between μA and μC is the open-circuit voltage (the highest voltage value) of the lithium-ion battery. When this voltage value is in the Eg range, the normal operation of an electrolyte can be ensured. Normal operation means that the lithium-ion battery moves back and forth between the positive and negative electrodes through the electrolyte, but does not undergo oxidation-reduction reactions with the electrolyte, So as to ensure the stability of the battery structure. The electrochemical potential of the positive and negative materials causes the electrolyte to work abnormally in two forms:

  1. When the electrochemical potential of the negative electrode is higher than the lowest electron and unoccupied energy level of the electrolyte, the electrons of the negative electrode will be captured by the electrolyte, and the electrolyte will be oxidized, then the reaction product will form a solid-liquid interface layer on the surface of the negative electrode material particles. As a result, the negative electrode may be damaged.
  2. When the electrochemical potential of the positive electrode is lower than the highest electron-occupied energy level of the electrolyte, the electrons in the electrolyte will be captured by the positive electrode and oxidized by the electrolyte. Then the reaction product forms a solid-liquid interface layer on the surface of the positive electrode material particles, resulting in the positive electrode may be damaged.

However, the possibility of damage to the positive or negative electrode is due to the existence of the solid-liquid interface layer, which prevents the further movement of electrons between the electrolyte and the positive and negative electrodes, and instead protects the electrode material.

That is to say, the lighter solid The liquid interface layer is protective. The premise of this protection is that the electrochemical potential of the positive and negative electrodes can slightly exceed the Eg interval, but not too much.

For example, the reason why most of the current lithium-ion battery anode materials use graphite is that the electrochemical potential of graphite related to Li/Li+ electrodes is about 0.2V, which slightly exceeds the Eg range (1V~4.5V), but because of its protective properties, the solid-liquid interface layer prevents the electrolyte from being further reduced, thus stopping the continuous development of the polarization reaction.

However, the 5V high-voltage cathode material is far beyond the Eg range of the current commercial organic electrolyte, so it is easily oxidized during charging and discharging. With the increase of charging and discharging times, the capacity decreases and the service life also decreases.

The reason why the open-circuit voltage of the lithium-ion battery is selected to be 4.2V is that the Eg range of the electrolyte of the existing commercial lithium-ion battery is 1V ~ 4.5V. If the open-circuit voltage is set to 4.5V, the output power of the lithium-ion battery may be increased, but it also increases the risk of battery overcharge, and the harm of overcharge has been explained by a lot of data, so there is no additional explanation here.

If you are interested in battery products, please don’t hesitate to contact us at any time!
Email: sales@himaxelectronics.com