Traditional lead-acid batteries, nickel-cadmium batteries, and nickel-hydrogen batteries are relatively mature in their own technology, but they are used as power batteries in automobiles. At present, more and more car manufacturers choose to use lithium batteries as the power battery for new energy vehicles.
Because lithium-ion power battery has the following advantages: high working voltage (three times that of nickel-cadmium battery hydrogen-nickel battery); large specific energy (up to 165WH/kg, which is three times that of hydrogen-nickel battery); small size; light weight Long cycle life; low self-discharge rate; no memory effect; no pollution.
Many well-known automakers are currently developing power lithium battery vehicles such as Ford, Chrysler, Toyota, Mitsubishi, Nissan, Hyundai, Courreges, and Ventury. Domestic automakers such as BYD, Geely, Chery, Lifan and ZTE have also installed power lithium batteries in their hybrid and pure electric vehicles.
The bottleneck that currently hinders the development of power lithium-ion batteries is: safety performance and management systems for automotive power batteries. In terms of safety performance, lithium-ion power batteries have high energy density, high operating temperature, and harsh working environment, as well as people-oriented safety concepts. Therefore, users place very high demands on battery safety. In the management system of the automobile power battery, since the working voltage of the automobile power battery is 12V or 24V, and the operating voltage of the single power lithium ion battery is 3.7V, it is necessary to increase the voltage by connecting a plurality of batteries in series, but it is difficult to implement the battery. Fully uniform charge and discharge, thus causing a single battery in a series of battery packs to be charged and discharged unbalanced, the battery will be undercharged and over-discharged, and this situation will lead to a sharp deterioration of battery performance, and ultimately As a result, the entire battery can not work properly, or even scrapped, which greatly affects the service life and reliability of the battery.