- Background Introduction With the increasing demand for energy, energy storage batteries have gradually become an important means to solve the problem of energy storage. However, as the use time increases, energy storage batteries will gradually experience problems such as capacity decline and battery aging, which may affect the safety and life of the battery.
- Why do we need to interrupt at the negative electrode? During the use of the battery, the charging and discharging process will cause chemical reactions inside the battery. When over-discharging or over-charging, the negative electrode of the battery will produce lithium positivity and adverse reactions. These reactions will form pollutants, such as SEI film and solid electrolyte interface layer. These pollutants will reduce the battery capacity and accelerate aging. In severe cases, they will also cause battery safety problems. Therefore, interruption at the negative electrode is very necessary.
- The role of energy storage battery in negative electrode interruption After the negative electrode is interrupted, the battery will no longer be driven by current, which can play a role in prohibiting over-discharge and over-charging, thereby ensuring the safety performance and life of the battery. In the energy storage battery system, the negative electrode interrupter is also used as a necessary backup safety system to increase the safety performance of the entire system.
- Analysis of the charging and discharging principle of lithium-ion batteries The working principle of energy storage batteries is based on the movement of lithium ions between the positive and negative electrodes. The positive electrode material is usually lithium iron phosphate (LiFePO4), while the negative electrode material is usually graphite, which has good lithium ion embedding and extraction capabilities. During the charging process, lithium ions are detached from the positive electrode material and transferred to the negative electrode through the electrolyte, while the released electrons flow to the negative electrode through the external circuit to form a current. The discharge process is the reverse movement of lithium ions, flowing from the negative electrode back to the positive electrode through the external circuit to release the stored electrical energy. This migration of lithium ions between the positive and negative electrodes is the key to achieving electrical energy storage and release. In summary, although in theory disconnecting either the positive or negative pole can achieve the purpose of power off, in actual operation, for safety reasons, it is usually recommended to disconnect both the positive and negative poles at the same time to avoid potential current flow and short circuit. In some specific cases, it is determined whether only the negative pole can be disconnected based on the specific situation.
- Application of disconnecting the negative electrode in the automotive field
In multiple scenarios, including power failure of the car battery, disassembly of the battery during long-term parking, and operations during charging, it is recommended to disconnect the negative terminal first. This practice is mainly for safety reasons to avoid potential short-circuit risks. For example, when the car battery is powered off, disconnecting the negative electrode can prevent metal tools from contacting the metal of the car body during disassembly to form a loop, thereby causing electrode damage or even fire. In addition, during the charging process, the positive electrode is connected first, and then the negative electrode is connected. When disassembling, the negative electrode should be removed first, and then the positive electrode. This is also to ensure safety and avoid short circuits or damage to electrical equipment in the car.
These practices together reflect the practice of giving priority to disconnecting the negative electrode in the energy storage battery system to ensure the safety of operation and the protection of equipment.
- Conclusion
Selecting a suitable negative electrode interrupter can effectively avoid pollutants caused by chemical reactions inside the battery, improve battery safety and reduce battery aging, thereby reducing battery maintenance costs and increasing system life. Therefore, energy storage batteries need to be interrupted at the negative electrode, and this principle should be followed in battery design and application.