New energy vehicle batteries are an important key point in the modern industry.
For new energy vehicles, the core is the battery, which accounts for 40% to 60% of the cost of the whole vehicle.
New energy vehicle batteries are mainly divided into the following types: ternary material lithium battery, lithium iron phosphate battery, lithium cobalt oxide battery, nickel metal hydride battery, hydrogen fuel cell, etc.
The main technical routes are the ternary lithium battery route represented by CATL and the lithium iron phosphate battery route represented by BYD.
Two commonly used lithium-ion batteries
Characteristics of lithium-ion batteries
Lithium-ion batteries are a type of battery that relies on lithium ions internally and electrons moving between positive and negative electrodes externally to function. Lithium-ion batteries have a relatively high energy density and can be recycled.
Advantages:
1. Light weight: Compared with other types of batteries, lithium batteries have a smaller volume and weight, making them easy to carry and use.
2. High specific energy: Lithium batteries have a higher specific energy and can provide a larger energy storage capacity, making them an excellent energy source.
3. No memory effect: Lithium batteries have no memory effect and do not need to be fully discharged and recharged, so they are more convenient for users to use.
4. Stable performance: The consumption rate of lithium batteries is relatively low, and the service life is long. The integrated circuit can also effectively control the battery power and ensure stability.
5. Environmental protection and safety: Lithium batteries do not contain flammable and explosive organic substances, so they are more environmentally friendly and safe.
Disadvantages:
1. Battery life: The life of lithium batteries is affected by factors such as the number of charge and discharge cycles and temperature, so you need to pay attention to the correct use method.
2. Safety hazards: Since lithium batteries become unstable under conditions of overcharge, overdischarge, and high temperature, they may explode, catch fire, and other problems, so they need to be used and stored reasonably.
3. High price: Compared with other types of batteries, lithium batteries have a higher cost.
4. Not suitable for low temperature environments: The capacity and cycle life of lithium batteries will decrease under low temperature conditions, so they are not suitable for extremely low temperature environments.
5. Charging speed: The charging speed of lithium batteries is slower than that of other types of batteries. Lithium batteries have great advantages in lightweight, high energy storage, stability, and no memory effect. But there are also some problems that need to be paid attention to, such as safety hazards and high prices.
01 Ternary lithium battery
Ternary lithium battery refers to a lithium battery whose positive electrode material is lithium nickel cobalt manganese ternary positive electrode material.
Advantages: Ternary lithium battery is safer. It is more suitable for the future development trend of new energy vehicle batteries, suitable for northern weather, and the battery is more stable at low temperatures.
Disadvantages: The voltage is too low, and the energy density is between lithium iron phosphate battery and cobalt oxide lithium battery.
Representative models include: BAIC New Energy EV200, BAIC New Energy EU260, Tesla Model 3, etc.
02 Lithium Iron Phosphate Battery
Lithium iron phosphate battery is a lithium-ion battery that uses lithium iron phosphate as the positive electrode material. (The positive electrode materials of lithium-ion batteries mainly include lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, ternary materials and lithium iron phosphate, etc.)
Advantages: Among the lithium batteries currently used in automobiles, the stability is the best.
Disadvantages: Compared with ternary lithium batteries and lithium cobalt oxide batteries, the energy density is still far behind. In addition, when the temperature is below -5℃, the charging efficiency is reduced. And when the temperature is too low, it will affect the capacity of the battery. Vehicles using lithium iron phosphate batteries are not suitable for driving in the north, especially in the northeast and other extremely cold areas, because the temperature in winter is too low, which will affect the service life of lithium iron phosphate batteries.
Representative models are: BYD e6, BYD Qin, BYD Tang, etc.
03 Lithium cobalt oxide battery
Lithium cobalt oxide battery is a relatively common battery in electronic products. It is commonly used in laptop batteries and used as batteries.
Advantages: mature production technology, high energy ratio, about twice that of lithium iron phosphate batteries.
Disadvantages: Under high temperature conditions, its stability is slightly worse than that of nickel cobalt manganese lithium batteries and lithium iron phosphate batteries.
Representative models include Tesla MODEL S
04 Nickel-metal hydride battery
Nickel-metal hydride battery is a new product developed on the basis of nickel-cadmium batteries in the late 1980s, synthesized by hydrogen ions and metallic nickel.
Advantages: The battery has a large energy reserve, is lighter, has a longer service life, and does not pollute the environment.
Disadvantages: The manufacturing cost is too high, and the performance is worse than that of “lithium batteries”.
Representative models include Toyota Prius, Ford Escape, Chevrolet Malibu, etc.
05 Hydrogen fuel cell
Although the word “battery” is included in the fuel cell, it is not an energy storage device in the traditional sense, but a power generation device. This is the biggest difference between fuel cells and traditional batteries.
Fuel cells are ideal “internal combustion engine substitutes”. Hydrogen is the main fuel for fuel cells. From the perspective of fuel safety, hydrogen is non-toxic and harmless, and the reactant is water, which is non-toxic, harmless, green and clean. Hydrogen has a low density, and when high-pressure hydrogen leaks and burns, it forms an upward torch and does not spread to the surroundings. Therefore, hydrogen safety is higher than fossil fuels such as natural gas and oil. From the perspective of performance, the energy conversion efficiency of fuel cells is 50-70%, the power density is about 3kW/L, and the power density of diesel engines is about 1.3kW/L. It is an ideal “internal combustion engine substitute”. The energy density of fuel cells can reach 500Wh/kg, and the cycle life is more than 4,000 times, which is better than lithium batteries.
Advantages: very high energy density; short hydrogen filling time, now it only takes 5 minutes to fill the high-pressure hydrogen fuel cell in Japan, and it can run 500 kilometers after filling.
Disadvantages: safe use of hydrogen; high storage and transportation costs; technology has not been industrialized and has not been verified by the market; cannot be connected to the grid for charging. In 2021, two hydrogen-powered vehicles have been publicly launched in certain markets. For example, Toyota Mirai and Hyundai Nexo, but they failed to be marketed. Currently, the focus of hydrogen fuel cell application development is in the field of commercial vehicles.
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