Power Battery Of Pure Electric Vehicle

Power battery is the key technology of electric vehicle, which determines its mileage and cost.
(1) Power battery required for pure electric vehicle
The functional and economic indicators of the power battery used in electric vehicles include: (1) safety; (2) Specific energy; (3) Specific power; (4) Life; (5) Circular price; (6) Energy conversion efficiency. These factors directly determine the utility and economy of electric vehicles.
(2) Supercapacitor
The advantages of supercapacitors are high quality to power and long cycle life. The disadvantages are low quality to energy and high purchase price. However, the cycle life is up to 500000~1 million times, so the single cycle price is not high. Parallel connection with lead-acid batteries and energy-type lithium-ion batteries can form a high-performance power supply system.
(3) Lead-acid battery
The production technology of lead-acid battery is mature, safe and cheap, and the waste battery is easy to be recycled. In recent years, through new technologies, its shortcomings such as low specific energy, short cycle life, acid fog during charging, and possible lead pollution in production are being overcome, and various indicators have been greatly improved, which can not only be better used as the power supply for electric bicycles and motorcycles, but also play a good role in electric vehicles.
(4) Lithium ion battery with lithium iron phosphate as cathode
The lithium battery with carbon negative electrode and lithium iron phosphate positive electrode has good comprehensive performance: high safety, no expensive raw materials, no harmful elements, cycle life up to 2000 times, and has overcome the shortcomings of low conductivity. The mass specific energy of the energy-type battery can reach 120Wh/kg. It can be used in parallel with the supercapacitor to form a comprehensive power supply. The mass specific energy of power type is also 70~80Wh/kg, which can be used alone without parallel connection of super capacitor. [5]
(5) Lithium ion battery with lithium titanate as negative electrode
The volume change of lithium titanate during charge-discharge is very small, which ensures the stability of the motor mechanism and the long life of the battery; The lithium titanate electrode point is high (1.5V relative to Li+/Li electrode), so lithium dendrites can not be generated during battery charging, which ensures the high safety of the battery. However, due to the high electrode potential of lithium titanate, even if it is paired with the lithium manganate anode with high electrode potential, the battery voltage is only about 2.2V, so the specific energy of the battery is only about 50-60Wh/kg. Even so, this kind of battery has outstanding advantages of high safety and long life, which is incomparable with other batteries.