Which Battery is Used in Electric Vehicles?

1. Lithium Iron Phosphate Battery

Lithium iron phosphate battery is one of the most common lithium batteries used in electric vehicles. It has good thermal stability up to 800°C. The service life and safety are more advantageous, and the energy density is low. These are the reasons why it has become a common battery for electric vehicles. However, Lithium iron phosphate battery has an obvious disadvantage: fear of low temperature. When the temperature is lower than -5°C, its charging efficiency decreases. Therefore, Lithium iron phosphate battery is not suitable for use in cold regions. Especially in countries located in extremely cold regions near the North Pole. Too low a temperature will greatly shorten the service life of the battery.

The BYD Yuan Plus has one of the longest ranges of electric cars currently produced in China. Equipped with 60.48kWh Lithium iron phosphate battery, the cruising range is 510km. The Lithium iron phosphate battery used by BYD Yuan Plus is a lithium-ion secondary battery. It has high discharge efficiency, good safety and long service life. These are in line with the characteristics of Lithium iron phosphate battery. According to relevant data, Lithium iron phosphate battery can be fast charged after 80% use, which can safely reach 4000 to 5000 times. After 70%, it can also guarantee 7000-8000 times, and the theoretical life can reach 7-8 years.

2. Ternary Lithium Battery

Ternary lithium battery refers to a lithium battery in which the positive electrode material uses nickel-cobalt lithium manganese oxide or nickel-cobalt lithium aluminate ternary positive electrode material. The ternary composite cathode material is made of nickel salt, cobalt salt, and manganese salt, and the ratio of nickel, cobalt, and manganese can be adjusted according to actual needs. Batteries with ternary materials as positive electrodes are safer than lithium cobalt oxide batteries. Suitable for power batteries or small batteries, especially batteries with relatively high capacity. At present, the batteries of ternary materials have replaced the lithium cobalt oxide batteries that were widely used before, and are widely used in the field of notebook batteries.

The early 18650 batteries were mostly Lithium iron phosphate batteries. With the improvement of technology, the current 18650 battery uses ternary material cells. The common capacity is 2200mAh-3600mAh.

Compared with lithium cobalt oxide, the voltage of Ternary lithium battery is generally lower, and its application range is limited. With the continuous improvement of formula and perfect structure, the nominal voltage of Ternary lithium battery has reached 3.7V, and the capacity has reached or exceeded the level of lithium cobalt oxide battery. The world’s top 5 battery brands SANYO, PANASONIC, SONY, LG, and SAMSUNG have launched batteries made of ternary materials. In terms of column batteries, SANYO and SAMSUNG have completely stopped producing lithium cobalt oxide batteries and turned to the manufacture of ternary batteries. At present, most of the small high-rate power batteries at home and abroad use ternary cathode materials.

Compared with Lithium iron phosphate battery, Ternary lithium battery has a much higher weight and energy density, about 200Wh/kg, which means that Ternary lithium battery with the same weight has a longer cruising range than Lithium iron phosphate battery. However, its shortcomings are also obvious. When its own temperature is 250-350 ° C, the internal chemical components begin to decompose, so it puts forward extremely high requirements for the battery management system, and it is necessary to install a safety device for each battery. In addition, due to the small size of the cells, the number of battery cells required for a bicycle is very large. Taking the Tesla Model S as an example, more than 8,000 18,650 Ternary lithium batteries can meet the assembly consumption of a car, which undoubtedly further increases the difficulty of controlling the battery management system. Therefore, among the models currently on sale in the market, only Tesla uses Ternary lithium battery.

As a well-known electric vehicle in the world, the Tesla Model S has a cruising range of 486 kilometers and a battery capacity of 85kWh. This is all due to the battery pack composed of 8142 3.4AH Panasonic 18650 Ternary lithium batteries.

3. Lithium Cobalt Oxide Battery

Lithium cobalt oxide battery is a type of lithium-ion battery. It has stable structure, high capacity ratio and outstanding comprehensive performance. But its safety is poor and the cost is very high. Mainly used for small and medium-sized batteries, widely used in small electronic devices such as notebook computers, mobile phones, MP3/4, etc., with a nominal voltage of 3.7V. Lithium cobalt oxide battery is mainly used in the manufacture of mobile phones and notebook computers and other portable electronic devices.

The application of Lithium cobalt oxide battery is still relatively small. The technology of cobalt lithium for small batteries is very mature, but the cost of cobalt lithium is too high now. Many companies use manganese lithium instead, and some are all manganese. Lithium cobalt oxide has stable performance and is currently the most mature technology for mobile phones, but the biggest disadvantage of the application is the high cost. Cobalt is a relatively rare strategic metal; in addition, it is also difficult to apply to power batteries. Tesla is the only company to use Lithium cobalt oxide battery type 18650 for its first electric car, the Roadster.

4. Nickel-Metal Hydride Battery

Nickel-metal hydride battery is improved from Nickel-cadmium battery. Replace cadmium in Nickel–cadmium batteries with metals that can absorb hydrogen. It offers higher capacitance than Nickel–cadmium battery at the same price, less obvious memory effect, and lower environmental pollution (does not contain toxic cadmium).

The recycling efficiency of Nickel-metal hydride battery is better than that of lithium-ion battery, and it is known as the most environmentally friendly battery. However, when compared with lithium-ion batteries, there is a certain memory effect. The old Nickel-metal hydride battery has a high self-discharge reaction, and the new nickel-metal hydride battery has a fairly low self-discharge (similar to alkaline), and can work at low temperature (-20°C).
Nickel-metal hydride battery has higher output current than carbon-zinc or alkaline battery. It is relatively more suitable for high power consumption products, and some special models even have higher output current than the ordinary previous generation Nickel–cadmium battery.

Nickel-metal hydride battery has a higher capacity (in terms of volume). Taking AA batteries as an example, the marked capacity of Nickel-metal hydride battery can reach 2900mAh, while that of alkaline batteries is only ~2100mAh (although the initial discharge voltage of alkaline batteries is generally higher than Nickel-metal hydride battery), of course, is much higher than the 1100mAh of the first-generation Nickel-cadmium battery, but it is still not as good as the lithium-ion battery.

Alkaline batteries may leak slightly corrosive and harmful liquids after a long period of non-use (which can be harmful to the human body or damage the device using the battery), while lithium batteries may burn or explode when improperly used. Relatively speaking, Nickel-metal hydride battery is a relatively safe battery.

Which type of battery is used in electric vehicles? There are various types of batteries used in electric vehicles, each with its own advantages and disadvantages. The electric vehicle industry is developing, and battery production technology will continue to mature. In the future, there will be more high-quality car batteries, which will promote greater progress in electric vehicles.