LiPO-US-NI-MH

LiPO-US-NI-MH

The biggest difference between NiMH and LiPo batteries is the chemical properties that enable the charging of the batteries. NiMH (Nickel-metal hybrid) uses nickel-based technology and LiPo (Lithium Polymer) batteries use a lithium-ion technology.

What the battery types have in common is that they both store a certain amount of energy depending on their capacity. Batteries can be manufactured with different voltages and capacities by installing battery cells in series or parallel inside the battery pack. One should be careful not to drop the batteries or damage the cases of the battery cells because it can cause a short circuit. Both battery types must be disposed of properly as hazardous waste.

The Batteries Differ in Their Properties and Uses.

NiMH batteries are easier to use. They must be fully discharged before charging and must be charged full before storing (Unless Manufacturer tells otherwise. Exampl. Traxxas). NiMH battery chargers are also very simple.

LiPo batteries don’t have to be fully discharged and they must be stored with a 50-70 % charge level. The charging must be done with a charger with balance charging. It is good to charge and store LiPo batteries in a LiPo safe bag.

Properties and remarks on NiMH batteries:

NI-MH-Battery

 

  • Easy and worry-free charging and storing “Safe choice for beginners”
  • Cheaper to manufacture
  • A common battery type in home appliances and devices
  • Rated voltage of cells 1.2V
  • Must be fully discharged before charging
  • Storing fully charged (Unless Manufacturer tells otherwise. Exampl. Traxxas)
  • Batteries are built with standard sized cells with metal cases
  • “Memory effect”: Batteries must always be fully discharged in order to keep full capacity available

Properties and remarks on LiPo batteries:

LiPO-Battery

  • Easy to use with the right devices
  • Manufacturing process is more complicated
  • Becoming a common battery type in home appliances and devices
  • Rated voltage of cells 3.0 V when discharging
  • A charger with balance charging must always be used for charging
  • Storing with 50-70 % charge level (Voltage per cell 3.85V-3.9V)
  • A LiPo safe bag must be used when charging and storing
  • Lighter than NiMH
  • Can be built in different sizes
  • “Memory effect”: almost non-existent, batteries don’t have to be fully discharged before recharging

The advantages of lithium batteries compared to NiMH batteries are undeniable.

The weight/power ratio in LiPo batteries is significantly better. LiPo batteries are noticeably lighter and they can store the same amount or more energy relative to their capacity than NiMH batteries. The power output of LiPo batteries is greater in quality and quantity. The power output of LiPo batteries is steady throughout the discharge, whereas the power output of NiMH batteries starts to decrease soon after charging because of higher discharge rate of the battery type.

Therefore with a LiPo battery with the same capacity as a NiMH battery a longer drive time and better performance can be achieved.

Battery Pack

With the increasing applications of lithium-ion batteries in drones, electric vehicles (EV), and solar energy storage, battery manufacturers are using modern technology and chemical composition to push the limits of battery testing and manufacturing capabilities.

Nowadays, every battery, regardless of its size, performance, and life, is determined in the manufacturing process, and the testing equipment is designed around specific batteries. However, since the lithium-ion battery market covers all shapes and capacities, it is difficult to create a single, integrated testing machine that can handle different capacities, currents, and physical shapes with required accuracy and precision.

As the demand for lithium-ion batteries becomes more diversified, we urgently need high-performing and flexible testing solutions to maximize the pros and cons and achieve cost-effectiveness.

The complexity of a lithium-ion battery

Today, lithium-ion batteries come in a variety of sizes, voltages, and applications that were originally not available when the technology was first put on the market. Lithium-ion batteries were originally designed for relatively small devices, such as notebook computers, cell phones, and other portable electronic devices.

Now, they’re a lot bigger in size for such devices as electric cars and solar battery storage. This means that a larger series, the parallel battery pack has a higher voltage, larger capacity, and larger physical volume. Some electric vehicles can have up to 100 pieces of cells in series and more than 50 in parallel.

A typical rechargeable lithium battery pack in an ordinary notebook computer consists of multiple batteries in series. However, due to the larger size of the battery pack, the testing becomes more complicated, which may affect the overall performance.

In order to achieve the best performance of the entire battery pack, each battery must be almost the same as its adjacent cells. Batteries will affect each other: if one of the batteries in a series has a low capacity, the other batteries in the battery pack will be below the optimal state. Their capacity will be degraded by the battery monitoring and rebalancing system to match the battery with the lowest performance.

The charge-discharge cycle further illustrates how a single battery can degrade the performance of the entire battery pack. The battery with the lowest capacity in the battery pack will reduce its charging state at the fastest speed, resulting in an unsafe voltage level and causing the entire battery pack to be unable to discharge again.

Battery Pack

When a battery pack is charged, the battery with the lowest capacity will be fully charged first, and the remaining batteries will not be charged further. In electric vehicles, this will result in a reduction in the effective overall available capacity, thereby reducing the vehicle’s range. In addition, the degradation of a low-capacity battery is accelerated because it reaches an excessively high voltage at the end of its charge and discharge before the safety measures take effect.

No matter the device, the more batteries in a battery pack that is stacked in series and in parallel, the more serious the problem.

The obvious solution is to ensure that each battery is manufactured exactly the same and to keep the same batteries in the same battery pack. However, due to the inherent manufacturing process of battery impedance and capacity, testing has become critical–not only to exclude defective parts but also to distinguish which batteries are the same and which battery packs to put in.

In addition, the charging and discharging curve of the battery in the manufacturing process has a great impact on its characteristics and is constantly changing.

Modern lithium-ion batteries bring new testing challenges

Battery testing is not a new thing, but, since its advent, lithium-ion batteries have brought new pressure to the accuracy of testing equipment, production capacity, and circuit board density.

Lithium-ion batteries are unique because of their extremely dense energy storage capacity, which may cause fires and explosions if they are improperly charged and discharged. In the manufacturing and testing process, this kind of energy storage technology requires very high accuracy, which is further aggravated by many new applications. The wide range of lithium-ion batteries that are available affects the testing equipment as they need to ensure that the correct charge and discharge curve is followed accurately in order to achieve the maximum storage capacity and reliability and quality.

Since there is no one size suitable for all batteries, choosing suitable test equipment and different manufacturers for different lithium-ion batteries will increase the test cost.

In addition, continuous industrial innovations mean that the constantly changing charge-discharge curve is further optimized, making the battery tester an important development tool for new battery technology. Regardless of the chemical and mechanical properties of lithium-ion batteries, there are countless charging and discharging methods in their manufacturing process, which pushes battery manufacturers to expect more unique test functions out of battery testers.

Accuracy is obviously a necessary capability. It not only refers to the ability to keep high current control accuracy at a very low level but also includes the ability to switch very quickly between charging and discharging modes and between different current levels. These requirements are not only driven by the need to mass-produce lithium-ion batteries with consistent characteristics and quality but also by the hope to use testing procedures and equipment as innovative tools to create a competitive advantage in the market.

12v-Battery-Pack

Although a variety of tests are required for different types of batteries, today’s testers are optimized for specific battery sizes. For example, if you are testing a large battery, a larger current is required, which translates to larger inductance, thicker wires, etc. So many aspects are involved when creating a tester that can handle high currents.

However, many factories do not only produce one type of battery. They may produce a complete set of large batteries for a customer while meeting all the test requirements for these batteries, or they may produce a set of smaller batteries with a smaller current for a smartphone customer.

This is the reason for the rising cost of testing–the battery tester is optimized for the current. Testers that can handle higher currents are generally larger and more expensive because they not only require larger silicon wafers but also magnetic components and wiring to meet electromigration rules and minimize voltage drops in the system. The factory needs to prepare a variety of testing equipment at any time to meet the production and inspection of various types of batteries. Due to the different types of batteries produced by the factory at different times, some testers may be incompatible with specific batteries and may be left unused.

Whether it is for today’s emerging factories for mass production of ordinary lithium-ion batteries or for battery manufacturers who want to use the testing process to create novel battery products, flexible test equipment must be used to adapt to a wider range of batteries’ capacity and physical size, thereby reducing capital investment and improving the return on investment.

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.”

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

High-Temperatures-Lipo-Battery

High-Temperatures-Lipo-Battery

Aerial photography enthusiasts try to shoot on sunny summer days, but flying under high temperatures for a long time can be a strain for their drones. Continuous flying under higher temperatures can easily cause serious heating of the equipment and may even cause battery failure or explosion and permanent damage to the drone’s equipment.

Factors that affect the work of drones in high temperature

Most drones use lithium polymer batteries, which generate electricity through chemical reactions. High temperatures affect the rate of chemical reactions, which undoubtedly shortens the flight time and life of the battery.

In sweltering temperatures, the air can be thicker. The thicker hot air forces the propellers and motors to work harder to keep the drone in the air and contributes to shorter flight time.

In some cases, once the battery heats up, it will gradually expand as time goes by while slowly emitting chemical substances and toxic smoke. The heat generated may also overheat the electronic equipment or melt wires and plastics.

Definitely take temperatures into account when you want to fly your drone. You can download free apps, like UAV Forecast, to help you make informed decisions before you fly.

We will explore some tips below if you decide to fly your drone in hot temperatures.

When flying a drone in hot weather, pay attention to certain factors

When switching out batteries, wait for the drone to cool down a bit, and take longer breaks between flights.

Reduce jerking your drone around or making sudden turns or stops during flight because high temperature will affect the discharge capacity of the battery and may shorten the service life of the drone.  In short, try to have a smooth flight.

Drones should indicate the operating temperature in their manuals, and it is best not to exceed a certain timeframe for flying under extreme temperatures. Here is a list of the operating temperatures of several drones for you to refer to:

operating temperatures of different drones | Grepow
Source: DJI, YUNEEC, Parrot, Autel Robotics, Skydio

The batteries must be fully charged and placed in a cool place before flying. Do not leave your electronics under direct sunlight.

If your drone is running hot after the flight, place it in a cool place to dissipate heat before storage.

Drone-Battery-lipo

Drone-Battery-lipo

You may have heard that there are restrictions when flying your drone in high temperatures, but did you know that it’s a similar case in low temperatures too?

We will explore some factors to consider if you plan on flying your drone in cold weather.

The impact of low temperatures on drones

Lower temperatures slow down the chemical reaction of LiPo (lithium-ion polymer) batteries, thereby reducing battery capacity, increasing resistance, and shortening the flight time. Drone manufacturer DJI states on its website that the LiPo batteries that power their drones start draining at an increased rate at temperatures below 59℉ (15°C).

It’s important that users read the manuals for their drones before a flight.  The operator temperature of most drones is set at 32 to 104 ℉ (0 to 40°C), so you should avoid flying outside of this temperature range.

To fly a drone in low-temperature, you need to prepare in all aspects.

Measure

Before going out

Plan your day out beforehand and try to finish your flight as soon as possible before it gets too dark. See the weather forecast: if there’s snow, hail, or rain, reschedule your flight as these weather conditions can damage your equipment and drones and very likely cause a crash.

Ensure your batteries are fully charged and have spare ones on hand to switch out.

When going out

Limit direct exposure of your batteries to the cold air. Keep them in their gear or protective equipment instead of just in the trunk of your vehicle.

Take off

When launching your drone, raise the aircraft 10-20 feet from the ground and make it hover for 30-60 seconds. This can increase the temperature of the battery to achieve a warm-up effect. Some apps, such as the DJI GO, allow you to check and monitor the battery temperature.

DJI GO | Temperature | Grepow
Source: DJI

Focus on the battery’s voltage. You should keep the battery’s voltage indicator displayed on your monitor so you can keep track of it.

Check the components. In a cold environment, some parts, like propellers, become more fragile. Therefore, it is necessary to check them more diligently for cracks or damage. You can also consider replacing them with solid carbon fiber blades.

Avoid running out of capacity. Fly until the battery drops to 30-40% of its capacity, and then bring the drone back down. In order to prevent other unpredictable situations from happening, don’t drain your battery completely when flying.

Stop flying immediately if it starts to rain or snow.  Be careful because most drones are not waterproof. Moisture may short-circuit the motor and cause the drone or controller to malfunction.

For you

Don’t forget to keep yourself warm. It is best to wear gloves which can touch the screen because it will be very inconvenient to operate the device with cold and stiff hands.

Wear goggles. When flying in icy or snow-covered weather, your eyes may be damaged due to the greater light reflection. Goggles can avoid this problem.

 

 

 

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.

Lithium-Ion-Battery

Lithium-Ion-BatteryThe 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.

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

Life-cycle-of-a-ternary-lithium-battery

With the promotion of energy conservation and environmental protection, more and more environmentally friendly products are being applied to the market. In the battery industry, ternary lithium batteries with many advantages quickly occupied the market, and gradually replace the traditional lead-acid batteries. For the traditional battery, ternary lithium batteries have a long life, energy-saving and environmental protection without pollution, low maintenance costs, charge and discharge completely, lightweight, and so on, the total ternary lithium battery life, how long it will be?

What is a ternary lithium battery?

In nature, lithium is the lightest metal with the smallest atomic mass. Its atomic weight is 6.94g/mol and ρ=0.53g/cm3. Lithium is chemically active and easily loses electrons and is oxidized to Li+. Therefore, the standard electrode potential is the most negative, -3.045V, and the electrochemical equivalent is the smallest, 0.26g/Ah. These characteristics decide that it is a material with high specific energy. Ternary lithium battery refers to the lithium secondary battery that uses three transition metal oxides of nickel-cobalt-manganese as the cathode material. It fully integrates the good cycling performance of lithium cobaltate, the high specific capacity of lithium nickelate, and the high safety and low cost of lithium manganate, which synthesizes nickel-cobalt-manganese and other multi-element synergistic lithium-embedded oxide by molecular level mixing, doping, coating, and surface modification methods. The ternary lithium battery is a kind of lithium-ion rechargeable battery that is widely researched and applied at present.

The life of ternary lithium battery

The so-called lithium battery life refers to capacity decay of nominal capacity with a period of battery use ( at room temperature 25 ℃, standard atmospheric pressure, and discharge at 0.2C)

can be considered the end of life. In the industry, the cycle life is generally calculated by the number of cycles of full charge and discharge of lithium batteries. In the process of use, an irreversible electrochemical reaction occurs inside the lithium battery, which leads to a decrease in capacity, such as the decomposition of the electrolyte, the deactivation of active materials, the collapse of the positive and negative structures, and the reduction in the number of lithium ions inserted and extracted. Experiments have shown that a higher discharge rate will lead to a faster attenuation of capacity. If the discharge current is lower, the battery voltage will be close to the equilibrium voltage and more energy can be released.

life of a ternary lithium battery
Life of ternary lithium battery 

The theoretical life of a ternary lithium battery is about 800 cycles, which is medium among commercially rechargeable lithium batteries. Lithium iron phosphate is about 2,000 cycles, while lithium titanate is said to reach 10,000 cycles. At present, mainstream battery manufacturers promise more than 500 times (charge and discharge under standard conditions) in the specifications of their ternary battery cells. Manufacturers recommend that the SOC use window is 10%~90%. Deep charging and discharging are not recommended, otherwise, it will cause irreversible damage to the positive and negative structure of the battery. If it is calculated by shallow charge and shallow discharge, the cycle life will be at least 1000 times. In addition, if the lithium battery is often discharged under high rate and high-temperature environment, the battery life will be greatly reduced to less than 200 times

The number of life cycles of lithium batteries is based on battery quality and battery materials.

  1. The cycle times of ternary materials are about 800 times.
  2. Lithium iron phosphate battery is cycled about 2500 times.

Grepow has long been manufacturing battery packs, ternary lithium batteries, lithium polymer batteries, lithium iron phosphate batteries, and so on. The product has a wide range of applications and high quality. Grepow is the world’s top battery manufacturer, which was founded in 1998, over 20 years of experience in battery manufacturing. There are currently 3 self-owned brands “格氏 ACE”, “GENS ACE” and “TATTU”.

In today’s lithium battery market, ternary lithium batteries are the most widely used. They are moderate in terms of performance and low in price. Therefore, the ternary lithium batteries are the most cost-effective.

Low-temperature lithium-ion batteries mainly include low-temperature lithium-ion polymer (LiPo) batteries, low-temperature 18650 batteries, and low-temperature lithium iron phosphate (LiPO4) batteries.  We will explore the advantages and disadvantages of each one.

Low-temperature lithium polymer batteries

Low-temperature LiPo batteries have the best low-temperature performance especially in smart wearable devices, where the advantages are more prominent.

Performance characteristics

Himax’s LiPo batteries can be made to operate in environments with low-temperatures of -50℃ to 50℃. Under low-temperatures, the batteries can achieve a lower internal resistance and, thus, a high discharge rate. Compared with traditional lithium polymer batteries, Himax’s batteries have broken through the discharge temperature limits of -20℃ to 60℃.

They are able to discharge over 60% efficiency at 0.2C at -40℃ and discharge over 80% efficiency at 0.2C at -30℃. When charged at 20℃ to 30℃ by 0.2C, the capacity can maintain above 85% after 300 cycles. The batteries can be ready for mass production, and they have been widely used in cold climates and military products.

Grepow low-temperature lithium polymer battery discharge curve

Shape advantage

With stacking technology, battery shapes can be widely customized, which allows for more flexibility and space within products. We can also create small and ultra-thin batteries with low-temperature characteristics used in special fields or professional smart equipment.

shaped batteries

Weight advantage

Under the same voltage and capacity conditions, low-temperature lithium-ion polymer batteries and low-temperature lithium iron phosphate batteries are lighter than low-temperature 18650 batteries. However, LiPo batteries are the most expensive in terms of production and manufacturing costs, which is one of the important factors limiting its use in some application areas.

Low-temperature 18650 lithium-ion batteries

Low-temperature 18650 lithium-ion batteries mainly consist of liquid electrolytes. these cylindrical batteries with steel shells have fixed dimensions, which means that their shape and size are fixed as well. The largest capacity is currently 3300mAh, which can only be achieved by a limited number of manufacturers.

Low-temperature 18650 lithium-ion batteries

Characteristics

At temperatures between -40℃ to 60℃, the effective discharge capacity is 40% to 55%, and the effective cycle life is more than 180 cycles.  At temperatures between -30℃ to 65℃ at 0.2C discharge, the effective discharge capacity is above 65%. At 1C rate discharge, the discharge capacity is above 60%, and the cycle life comes out to more than 200 cycles.

At temperatures between -20℃ to 75℃, the effective discharge capacity is more than 80%, and the cycle life is more than 300 cycles.

Due to the fixed performance and size of the battery, there is limited use for this battery, but its production and manufacturing costs are relatively low.

Low-temperature lithium iron phosphate batteries

Low-temperature LiPO4 batteries have two kinds of packaging cases: one is a steel case, which is currently mostly used in new energy batteries, such as energy-storage batteries and new energy vehicle batteries; the other is a soft-pack LiPO4 battery with aluminum plastic film for the outer packaging.

The performance of this battery is basically the same as that of the LiPo battery. However, the low-temperature performance of LiPo batteries is better than that of 18650 batteries. The development of LiPO4-battery technology has not been long, and the requirements for production equipment are relatively high.