Why BMS Li-ion battery Management system?
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2023/08/25 15:17:29
Lithium-ion batteries are widely used in long standby remote monitoring instruments because of their high operating voltage, small size, light weight, high energy density, no memory effect, no pollution, small self-discharge, long cycle life and other characteristics. Compared with nickel-metal hydride batteries, lithium-ion batteries are 30-40% lighter and 60% higher in energy ratio. However, lithium-ion batteries also have serious defects, which can be summarized in the following two aspects:
(1) Safety
Lithium-ion batteries are poor in safety and have defects such as explosions. In particular, lithium-ion batteries with lithium cobaltate as the positive electrode material can not be discharged at large current, and the safety is poor. In addition, almost all lithium-ion batteries overcharge or overdischarge will cause irreversible damage to the battery.
Lithium-ion batteries are also sensitive to temperature: if the temperature is too high, it may cause the electrolyte to decompose, burn or even explode; If the temperature is too low, the performance of the lithium-ion battery will deteriorate significantly, affecting the normal use of the equipment.
Due to the limitations of the lithium-ion battery manufacturing process, the internal resistance and capacity of each battery will be different. When multiple lithium-ion batteries are used in series, the charge and discharge rate of each battery is inconsistent, resulting in low battery capacity utilization. In view of this, in the actual use of lithium-ion batteries in the process of a special protection system to monitor the health of the battery, so as to manage the use of lithium-ion batteries.
(2) Maintainability
At low temperatures, capacity decay and power cannot be accurately predicted, which makes the equipment less maintainable. Instruments that are online for a long time have to be replaced regularly, and remote monitoring equipment works in scattered locations, and the distance between each location is long, so the work of replacing batteries is large and the cost is high.
In order to reduce the maintenance workload and reduce the maintenance cost, the lithium-ion battery management system should have an accurate power state estimation function, accurately grasp the power state of the lithium-ion battery, and more targeted battery replacement work. At the same time, the lithium-ion battery management system should have a low power consumption to reduce the maintenance frequency and extend the battery life. Therefore, the reasonable design of lithium-ion battery management system is of great significance to the maintenance of long-term continuous power supply remote monitoring instrument.
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