What Is an EV Battery?
An EV battery, also known as a storage battery or rechargeable battery, is installed in electric vehicles and can be repeatedly charged and discharged. The capacity and performance of these batteries are crucial, as they determine the cruising range per charge and the maximum power output of EVs.
EV battery types include lead-acid batteries, nickel-metal hydride batteries, and lithium-ion batteries. Currently, lithium-ion batteries are the most common due to their high energy density, high capacity, and cost-effectiveness.
Uses of EV Batteries
EV batteries are used in two distinct applications:
The first is the drive battery, which provides the primary power for driving the vehicle. High-capacity lithium-ion batteries are typically used for this purpose in modern EVs.
The second is the auxiliary battery that powers systems such as lights and audio equipment, similar to traditional combustion engine cars, providing 12V DC electricity. Lead-acid batteries are generally used for these auxiliary functions.
Principle of EV Batteries
Most EV batteries on the market today are lithium-ion based. These batteries are composed of a positive electrode, a negative electrode, a separator, and an electrolyte. The reversible movement of lithium ions between the electrodes during charging and discharging allows for their repeated use.
Lithium-ion batteries come in three main shapes: cylindrical, pouch, and prismatic.
Cylindrical: Despite being less common in automotive applications due to spatial inefficiency, cylindrical batteries are used by companies like Tesla for their low cost and high energy density.
Pouch type: Pouch batteries are wrapped in a thin laminated film and are known for being space-efficient and powerful. They are considered promising for future applications and are used in vehicles like the Nissan LEAF.
Prismatic type: This compact and thin design is well-balanced in terms of mechanical strength, energy density, and size, making it a popular choice for in-vehicle applications. Major automakers like Toyota use this type of battery.