Overview of New Energy Vehicle Power Batteries
Power batteries are the power source of electric vehicles, energy storage devices, and the key factor restricting the development of electric vehicles. In order for electric vehicles to compete with fuel vehicles, the key is to develop power batteries with high specific energy, high specific power, long service life and low cost.
(1) Common terms and performance indicators of electric vehicle power batteries
State of Charge (SOC): The percentage of the remaining battery capacity to the total capacity.
State of Health (SOH): Provides information on the battery health status.
Battery Management System (BMS): Real-time monitoring of power battery operating parameters, fault diagnosis, SOC estimation, mileage estimation, short circuit protection, leakage monitoring, display alarm, charge and discharge mode selection, etc., to ensure efficient, reliable and safe operation of electric vehicles.
Specific energy (Wh/kg): The amount of electrical energy released by a unit mass of electrode material, which indicates the endurance of electric vehicles in pure electric mode.
Specific power (W/kg): The power that a unit mass of battery can provide, which is used to judge the acceleration performance and maximum speed of electric vehicles and directly affects the power performance of electric vehicles.
Cycle life: The number of times a battery is charged and discharged in one week, which is an important indicator for measuring the life of a power battery. The more cycles, the longer the power battery can be used. Battery discharge rate, that is, a measure of discharge speed.
Battery discharge C (multiple) rate: It indicates the rate of battery discharge, that is, a measure of the speed of discharge. The discharge of the entire capacity of the battery in 1 hour is called 1C discharge.
Depth of discharge (DOD): It refers to the ratio of the capacity discharged by the battery to the rated capacity of the battery.
(2) Performance requirements for electric vehicle power batteries
As an energy storage device for vehicles, electric vehicle batteries must have sufficient energy to meet certain driving cycles and mileage, and must also provide the maximum power required to achieve the vehicle's specified acceleration performance. In other words, power batteries must have good charge and discharge performance, high specific power and specific energy, low price, and easy use and maintenance.
(3) Types of power batteries for electric vehicles
The following three types of power batteries are commonly used in electric vehicles:
Chemical battery: a device that converts chemical energy into electrical energy. It is structurally divided into two main categories: storage battery and fuel cell.
Physical battery: a device that relies on physical changes to provide and store electrical energy, such as supercapacitors, flywheel batteries and solar cells.
Biobattery: a device that generates electricity through biochemical reactions. For example, microbial batteries use the anode of the battery to replace natural electron acceptors such as oxygen or nitrates, and generate electrical energy through the continuous transfer of electrons.
