The battery of the pure electric vehicle is introduced

There are two categories of batteries for electric vehicles, batteries and fuel cells. Batteries suitable for pure electric vehicles include lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, sodium-sulphur batteries, secondary Lithium Batteries, and air batteries. Among them, lead-acid batteries, nickel-cadmium batteries and nickel-metal hydride batteries appeared earlier, and have generally been eliminated as battery types, and today's mainstream pure electric vehicles are basically lithium batteries, mainly including lithium cobalt acid batteries, such as Tesla products; lithium manganate batteries, such as Toyota Prius, Nissan Leaf; Lithium Iron Phosphate Batteries, such as BYD products, Zhinuo 1E, etc.

Lead acid battery is the most commonly used battery in new energy vehicles. The plate of lead-acid battery is a grid made of lead alloy, the electrolyte is dilute sulfuric acid, and the two plates are covered with lead sulfate. However, after charging, the lead sulphate on the plate at the positive electrode is converted to lead dioxide, and the lead sulphate at the negative electrode is converted to metallic lead. When the battery is discharged, a chemical reaction takes place in the opposite direction. The advantage of lead-acid batteries is that the electromotive force is more stable when discharged, the disadvantage is that the energy is low and the environment is corrosive.

Nickel-metal hydride batteries are widely used in new energy hybrid vehicles, which have a high energy density ratio and can effectively extend the driving time of vehicles. In addition, nickel-metal hydride batteries have smooth discharge characteristics, smooth discharge curve, small calorific value but large volume and pollution.

Compared with lead-acid and nickel-metal hydride batteries, lithium-ion batteries have advantages such as high operating voltage, high specific energy, small size, light weight, long cycle life, low self-discharge rate, no memory effect and no pollution. Therefore, more and more automobile manufacturers are choosing lithium-ion batteries as the power batteries for pure electric vehicles.

There are three most commonly used lithium-ion batteries, which are lithium cobalt acid batteries, lithium manganese acid batteries and lithium iron phosphate batteries. The lithium cobalt acid battery has high efficiency, large discharge current, high charging speed and light weight, but the disadvantage is that the stability is relatively poor, which is why this battery technology is difficult to manufacture large capacity battery cells. The lithium manganese acid battery costs slightly less and is not as radical as lithium cobalt acid, the low temperature performance is better, more suitable for use in cold areas, but the high temperature stability is not good enough, easy to bulge, and the cycle life declines faster.

Lithium iron phosphate batteries are known as the safest automotive battery technology, because compared with lithium cobalt acid batteries and lithium manganese acid batteries, the stability of lithium iron phosphate batteries, especially at high temperatures, is much more stable, and the chance of accidents such as fire is less. However, lithium iron phosphate batteries are not as efficient as these two battery technologies, and the weight required to store the same amount of energy is about twice that of lithium cobalt oxide batteries, so it is no wonder that this new battery technology has been a difficult choice for high performance electric sports cars.