,

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.

,

The Difference Between Steel-shell, Aluminum-shell And Pouch-cell Batteries

Structure-Of-Steel

The shell materials used in lithium batteries on the market can be roughly divided into three types: steel shell, aluminum shell and pouch cell (i.e. aluminum plastic film, soft pack). We will explore the characteristics, applications and differences between them in this article.

Steel–Shell Battery

The steel material for this battery is physically stable with its stress resistance higher than aluminum shell material. It is mostly used as the shell material of cylindrical lithium batteries.

Structure-Of-Steel

In order to prevent oxidation of the steel battery’s positive electrode active material,  manufacturers usually use nickel plating to protect the iron matrix of the steel shell and place a safety device inside the battery cell.

At present, most laptops use steel-shell batteries, but it is also used in toy models and power tools.

Aluminum–Shell Battery

The aluminum shell is a battery shell made of aluminum alloy material. It is mainly used in square lithium batteries. They are environmentally friendly and lighter than steel while having strong plasticity and stable chemical properties.

Generally, the material of the aluminum shell is aluminum-manganese alloy, and its main alloy components are Mn, Cu, Mg, Si, and Fe. These five alloys play different roles in the aluminum shell battery. For example, Cu and Mg improve strength and hardness, Mn improves corrosion resistance, Si can enhance the heat treatment effect of magnesium-containing aluminum alloys, and Fe can improve high temperature strength.

Structure-Of-Aluminum-Shell-Battery

Aluminum shell batteries are the main shell material of liquid lithium batteries, which is used in almost all areas involved.

Pouch–Cell Battery

The pouch-cell battery (soft pack battery) is a liquid lithium-ion battery covered with a polymer shell. The biggest difference from other batteries is its packaging material, aluminum plastic film, which is also the most important and technically difficult material in pouch cells.

The packaging materials are usually divided into three layers: the outer barrier layer (it is usually an outer protective layer composed of nylon BOPA or PET), barrier layer (middle layer aluminum foil) and inner layer (multifunctional high barrier layer). The materials such as positive electrode, negative electrode, electrolyte, separator and so on are similar to other types of batteries.

Structure-Of-Pouch-Cell-Battery

The hidden danger of lithium batteries is the instability of the material or other unexpected comprehensive factors, which may cause the heat to run out of control and result in gas accumulation in the battery. This is dangerous because steel-shell and aluminum-shell batteries have a fixed space. When the gas inside these batteries expands beyond the limits of this space, the battery will explode. Pouch cells will also bulge up and crack, so they have a higher safety index.

Compared with steel and aluminum batteries (i.e. hard-shell batteries), pouch-cell batteries can have a flexible design, low internal resistance, more cycle time, and high energy density. They are lightweight, and they do not explode easily.

Pouch-cell batteries are 40% lighter than steel-shell lithium batteries of the same capacity and 20% lighter than aluminum-shell batteries. The capacity can be 10-15% higher than steel-shell batteries of the same size and 5-10% higher than aluminum-shell batteries of the same size.

In light of the advantages of pouch-cell batteries, industry experts predict that pouch-cell batteries will have a higher chance of penetrating the new energy vehicle market with more development.  In the future, pouch-cell batteries are expected to account for more than 50% of all types of batteries.

In addition to being used as power batteries and energy storage batteries, pouch-cell batteries are also used as battery components for 3C electronic products, such as mobile phones, drones, wearable devices, RCs, etc.

, ,

The Difference Between Lipo And NiMH Battery

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.

,

Multifunctional Lithium Battery Testing

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.

, ,

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.”

,

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

,

Using Drones Under High Temperatures

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.

,

Can I Fly My Drone In The Winter?

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.

 

 

 

,

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.

,

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