Power Batteries For Pure Electric Vehicles

Power batteries are a key technology for electric vehicles, determining their range and cost.
(1) Power batteries required for pure electric vehicles
The functional and economic indicators required for power batteries used in electric vehicles include: (1) safety; (2) Specific energy; (3) Specific power; (4) Lifespan; (5) Circular price; (6) Energy conversion efficiency. These factors directly determine the usability and economy of electric vehicles.
(2) Supercapacitor
The advantages of supercapacitors are high quality compared to power and long cycle life, while their weaknesses are low quality compared to energy and expensive purchase price. However, the cycle life can reach 500000 to 1 million times, so the price of a single cycle 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 batteries is mature, with good safety, low price, and easy recycling and regeneration of waste batteries. In recent years, through new technology, its shortcomings such as low specific energy, short cycle life, acid fog during charging, and possible lead pollution in production have been constantly overcome, and various indicators have been greatly improved, which can not only be better used as power supply for electric bicycles and electric motorcycle, but also play a good role in electric vehicles.
(4) Lithium ion batteries with lithium iron phosphate as the positive electrode
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, a cycle life of up to 2000 times, and has overcome the disadvantage of low conductivity. The mass to energy ratio of energy type batteries can reach 120Wh/kg, and can be used in parallel with supercapacitors to form a high-performance power supply. The mass to energy ratio of the power type is also 70-80Wh/kg, which can be used alone without the need for parallel connection of supercapacitors. [5]
(5) Lithium ion batteries with lithium titanate as negative electrode
Lithium titanate has minimal volume change during charging and discharging, ensuring the stability of the motor mechanism and the long lifespan of the battery; The lithium titanate electrode has a high point position (1.5V relative to Li+/Li electrodes), which prevents the generation of lithium crystal branches during battery charging, ensuring high safety of the battery. However, due to the high electrode potential of lithium titanate, even when paired with a lithium manganese oxide positive electrode with a 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, the outstanding advantages of high safety and long lifespan of this type of battery are unparalleled by other batteries.