The electric vehicle battery is one of the most important components of the automotive system. In pure electric vehicles, the battery is the only “life”. Because only the electricity stored in the battery is the only energy source to drive pure electric vehicles.
However, different battery types differ greatly in terms of range, charging speed, and service life. In fact, even the safety of electric vehicles is determined by the battery pack.
Electric vehicle batteries are different from SLI batteries (starting, lightning, and ignition). SLI batteries are batteries that are usually installed in gasoline or diesel vehicles. This type of electric vehicle battery is designed as an energy storage system that can provide electricity in a long-term, sustainable manner.
Let’s focus on the four most used EV battery types on the market:
- Lithium-ion battery
- Lead-acid battery
- Nickel metal hydride battery
- Solid-state battery
Lithium-ion batteries
The most widely used electric vehicle battery is lithium battery, before this, he has been widely used in mobile phones, computers and other electronic equipment, the main difference is the size of the use.
Compared to other batteries, lithium-ion batteries are favored because of their high energy per unit mass. They also have advantages such as high power to weight ratio, energy efficiency, high temperature performance and low self-discharge.
Common lithium-ion batteries are as follows
- Nickel Manganese Cobalt (NMC)
- lithium cobaltate (LCO)
- Nickel cobalt Aluminum (NCA)
- Lithium iron phosphate (LFP)
- Lithium Manganese oxide (LMO)
- Lithium titanate (LTO)
NMC and NCA offer the best performance, but also the highest cost. Some of the longest range lithium-ion battery electric vehicles can travel more than 500 miles on a full charge. Therefore, such batteries are basically found in high-end or high-performance electric vehicles. LFP batteries are cheaper because their capacitance density is lower, but they are more stable and safe. Car companies like BYD, which pay attention to cost performance, use LFP batteries on many models.
Lead-acid batteries
Lead-acid batteries were the first electric car batteries. As a mature technology, lead acid is cheap, safe and reliable. However, the problems of large weight, low specific energy, poor low temperature performance, and short life cycle of use lead to few manufacturers choosing to use it.
At present, lead-acid batteries are mainly used for the auxiliary electrical system power supply of electric vehicles and the start-stop function of internal combustion engine vehicles.
Nickel metal hydride battery
After automakers phase out lead-acid batteries, they usually use nickel-metal hydride batteries as a replacement. It is widely used in hybrid electric vehicles (HEV), but also successfully used in some pure electric vehicles.
NiMH batteries have a longer life cycle than lithium-ion or SLA batteries. Nickel-metal hydride batteries are very safe and can tolerate misuse.
But nickel-metal hydride batteries have not been widely used in the electric vehicle industry, mainly because of the following three shortcomings
- The price is relatively expensive
- High self-discharge rate, fast discharge speed, not suitable for long-distance driving of cars
- It is easy to produce a lot of heat at high temperatures, resulting in low work efficiency.
Solid state battery
All-solid-state batteries because of their “high energy density”, “high safety” and “high charging speed” are considered to be the ultimate answer to solve the various anxieties of electric vehicle owners.
However, solid-state batteries are still in a state of development, because the manufacturing process of solid-state batteries is complex and expensive, and can not be used on a large scale in electric vehicles.