Why BMS lithium ion battery management system?
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2023/03/27 11:24:34
Lithium-ion battery is widely used in long standby remote monitoring instrument because of its high working 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) Security
Lithium-ion batteries are poor in safety and have defects such as explosions. In particular, lithium-ion batteries with lithium cobaltate as the cathode material cannot discharge under large current, so the safety is poor. In addition, almost all lithium-ion batteries can cause irreversible damage to the battery if they are overcharged or overdischarged.
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 lithium-ion batteries will deteriorate significantly, affecting the normal use of equipment.
Due to the limitations of the lithium-ion battery manufacturing process, the internal resistance and capacity of each battery will vary. When multiple lithium-ion batteries are used in series, the charge and discharge rates of each battery are inconsistent, resulting in low capacity utilization. In view of this, a special protection system is required to monitor the health of the battery during the actual use of lithium ion batteries, so as to manage the use of lithium ion batteries.
(2) Maintainability
At low temperatures, capacity decay and power cannot be accurately predicted, making equipment less maintainable. Instruments that have been online for a long time have to be replaced regularly, while remote monitoring equipment works in scattered locations with long distances between each location, so battery replacement is a lot of work and cost.
In order to reduce the maintenance workload and reduce the maintenance cost, the lithium ion battery management system should have the accurate power status estimation function, accurately grasp the power status of lithium ion batteries, and more targeted battery replacement work. At the same time, the lithium-ion battery management system should have low power consumption to reduce the maintenance frequency and extend the battery life. Therefore, the rational 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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