Lithium-ion (Li-ion) batteries are inarguably the most popular type of rechargeable battery for consumer electronics. They can be used for a variety of products from mobile phones to cars, and their qualities are superior compared to other rechargeable batteries.

At NightSearcher we use high-quality lithium-ion (Li-ion) batteries for all but a few of our rechargeable flashlights, searchlights, head torches, and floodlights, as they allow us to provide the high-performance, durable products our customers are used to.

Below we’ve listed the biggest advantages of lithium-ion batteries from the customers’ point of view and delved into the science behind each characteristic.

Eco-friendly:

Lightweight and compact:

High energy density = A bigger punch:

Lithium is a highly reactive element with the ability to release and store large amounts of energy, allowing li-ion batteries to pack a high energy capacity in a small size. This translates to lithium-ion batteries lasting much longer between charges than other rechargeable batteries, while still maintaining their high level of performance.

A typical lithium-ion cell (= battery) has an average cell voltage of 3.6V, whereas a nickel-metal hydride (NiMH) cell averages at 1.2V, meaning three Ni-MH batteries are required to match the output of a single lithium-ion battery.

Low maintenance:

Older types of rechargeable batteries, such as nickel-cadmium or nickel-metal hydride batteries had a so-called “memory effect”, or “lazy battery effect”: If they were repeatedly partially discharged before being recharged, ultimately the battery would only deliver the amount of energy that was used during the partial discharges before its voltage would drop. To avoid this, NiCd and NiMH batteries would need to be regularly maintained by completely discharging and recharging them.

Lithium-ion batteries don’t suffer from the memory effect, which means they always give up their last bit of power, and you can recharge them whether you’ve used 100% or 25% of their capacity with no pesky maintenance needed!

More charge cycles:

Quality lithium-ion batteries last about a 1000 full charge cycles. A full charge cycle is when the battery is discharged to flat and then recharged to full, so using your battery until it’s at 75% capacity and then plugging it into recharge doesn’t constitute a full charge cycle. When your battery has recharged back to full, you can still use the 75% of the capacity that you were left with before you recharged your battery; only then has your battery gone through a full charge cycle.

Low self-discharge rate

Lithium-ion batteries also have a relatively low self-discharge rate. Self-discharge is a natural, irreversible phenomenon for batteries, where chemical reactions inside the batteries reduce their capacity even when the battery is not being used. The self-discharge rate of lithium-ion batteries peaks at about 5% within the first 24 hours after charging the battery, and then tapers off to 1-2% per month. In comparison, nickel-based rechargeable batteries lose about 10-15% of their capacity after charge and another 10-15% per month.

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.

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.

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.

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 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.