A power battery consists of cells and other components. If other components fail, the battery will not work properly. If the connection board or wiring harness is disconnected or detached, the battery will naturally become unusable. Faults in the battery cooling system can also affect battery use. However, the main problem faced by car owners using the battery normally is the natural degradation of the cell performance.
Currently, the main types of batteries used in new energy vehicles are lithium iron phosphate batteries and ternary lithium batteries. They are both lithium batteries, and their names represent the materials used in the anode of the battery.
Lithium iron phosphate batteries have been widely adopted due to their good thermal stability and low cost, but they have low energy density, are heavy and weak, and suffer from severe energy degradation at low temperatures, so they have been gradually replaced by ternary lithium batteries.
Ternary lithium batteries have high energy density and better low-temperature stability. Many BAIC New Energy models and Tesla Model 3 use ternary lithium batteries. However, they are susceptible to high temperatures, are prone to catching fire if not properly controlled, and still have a limited lifespan.
Lithium-ion batteries primarily convert chemical energy into electrical energy through redox reactions. When the battery discharges, substance A inside transforms into substance B, converting chemical energy into electrical energy; conversely, during charging, substance B transforms back into substance A, converting electrical energy back into chemical energy for storage. Lithium ions continuously insert into and extract from the positive and negative electrode material layers within the battery, forming a cycle. Different batteries use different anode materials, resulting in different battery characteristics.
In addition, many side reactions occur during battery operation, including the dissolution of active materials, decomposition of electrolyte, and corrosion of electrode materials. The surfaces of the positive and negative electrode materials may deform or become caked with byproducts of side reactions, blocking the channels for lithium-ion exchange. Just like a blocked air intake in a traditional car prevents the engine from working properly, the internal resistance of the battery increases, resulting in incomplete discharge and a lower discharge plateau, which manifests as battery capacity decay.
To reduce the capacity degradation of lithium batteries, you should pay attention to the following:
1. Ensuring the battery operates at normal temperatures (generally between 0 and 40°C) can minimize side reactions;
2. Minimize the use of fast charging. Fast charging involves high voltage, which can easily lead to overcharging of the battery, causing lithium ions to deposit on the separator or electrode surface. In addition, the temperature is relatively high during fast charging, which can easily cause irreversible damage to ternary lithium batteries.
3. Avoid sudden acceleration and other actions. Batteries need to be stable; sudden changes in current can easily cause internal side reactions, leading to battery damage.
4. Shallow charging and discharging: For lithium batteries, full charging and discharging can actually reduce battery life, especially for ternary lithium batteries. It is suitable to charge when there is about 20% of the power remaining. Do not overuse them. This is different from what is said online.
