With the introduction of the new national standard, the era of lithium-ion batteries has arrived. Lithium-ion batteries for electric vehicles on the market are mainly divided into three categories: first, ternary lithium (currently the most widely used); second, lithium iron phosphate; and third, lithium titanate. So, what precautions should be taken when using lithium-ion batteries?
First, temperature. Lithium-ion batteries are sensitive to high temperatures. Prolonged exposure to excessive heat will significantly reduce the lifespan of lithium-ion batteries. In severe cases, the increased internal pressure can lead to an explosion. Even if it doesn't explode, lithium-ion batteries will quickly fail due to high temperatures, mostly because of the high temperatures in their operating environment.
The second major factor is the discharge current. For example, if an 18650 battery cell is designed for 3C discharge, but your electric vehicle is 8000W, using a battery cell with a lower discharge current than your vehicle will cause the lithium-ion battery to overheat, have excessive current, and shorten its lifespan. It may even lead to bulging and eventual failure. If your electric vehicle has very high power and speed, it is recommended to choose an 10C current 18650 battery cell. Therefore, choosing the right battery cell is obviously very important!
Thirdly, storing a fully charged battery is crucial. A ternary lithium battery's full charge is 4.35V, but most protection boards on the market stop charging at 4.2V. This is why many electric vehicle lithium-ion batteries don't have the advertised capacity. Generally, for long-term storage of electric vehicle lithium-ion batteries, it's best to charge them to about 50% capacity, similar to how a new mobile phone is often turned on at 50% battery. Prolonged storage at full charge will reduce the battery's capacity. This excludes lithium iron phosphate and lithium titanate batteries, which can be stored fully charged. It's also important to choose a high-quality protection board. The biggest taboo for lithium-ion batteries is overcharging and over-discharging. A single over-discharge of a ternary lithium battery will render it unusable, and overcharging will inevitably cause bulging and render it unusable as well.
Fourthly, suitable charging equipment is essential. During charging and discharging, the charger's current and the appliance's normal current load must be within the specified range. Excessive current load can easily cause internal short circuits in the battery, damaging lithium ions and creating safety hazards. Similarly, the same principle applies to the voltage of rechargeable chargers. Therefore, when using a charger, it's crucial to check whether it is up to standard.
Lithium iron phosphate (LFP) batteries are lithium-ion batteries that use lithium iron phosphate as the cathode material. In the early stages of the development of new energy vehicles, LFP batteries became the first choice for major manufacturers due to their superior thermal stability, good safety, and low development cost.
However, with the continuous development of technology, ternary lithium-ion batteries with superior performance have emerged. In comparison, lithium iron phosphate batteries have lower energy density. Under the same driving range, vehicles equipped with lithium iron phosphate batteries are heavier, which directly leads to unsatisfactory energy consumption.
Furthermore, the national requirements for the energy density of batteries for new energy vehicles are increasing year by year. Due to material limitations, the energy density of lithium iron phosphate batteries is difficult to increase further, so many manufacturers are gradually shifting to the development of ternary lithium-ion batteries.
Ternary lithium-ion batteries refer to lithium-ion batteries that use lithium nickel cobalt manganese potassium ternary cathode materials. Compared with the lithium iron phosphate batteries introduced earlier, they have higher energy density, more reasonable price, and better overall performance, making them the battery type used in most new energy vehicles.
Despite its seemingly perfect design, the ternary lithium-ion battery has been questioned for its shortcomings. The biggest drawback is its decomposition at around 200 degrees Celsius. Under high-temperature conditions, the electrolyte can burn rapidly, increasing the risk of spontaneous combustion or explosion. However, with technological advancements, many manufacturers have developed excellent battery management systems, improving safety and earning recognition from major automakers for their superior performance.
Previously, BYD, a domestic new energy giant that had been vigorously developing lithium iron phosphate batteries, currently uses ternary lithium-ion batteries in its new energy passenger vehicles. Ternary lithium-ion batteries have now become the mainstream battery for new energy vehicles.
Hydrogen fuel cell batteries have long been considered a future direction for new energy vehicle batteries. The most basic principle of hydrogen fuel cell batteries is the reverse reaction of water electrolysis. The biggest difference between hydrogen fuel cell batteries and rechargeable batteries is that they don't require charging. They only need to be filled with hydrogen, and when the hydrogen runs out, you can refill them at a designated location. This makes them very convenient to use, unlike rechargeable batteries which require a significant amount of time to charge.
