1. Do you know BMS?
BMS(battery management system) is the link between the battery and the user, and its main purpose is to improve the utilization rate of the battery and prevent the overcharging and discharging of the battery.
2. What functions should be realized by BMS?
Generally, for the battery management system BMS, the following functions need to be realized:
1). Monitoring and management of the working state of the battery pack - voltage monitoring, current monitoring, temperature monitoring, SOC (State of Charge) estimation, balance control, etc
2). Management of abnormal state of battery pack - overcharge, overdischarge, overcurrent, temperature overrun, imbalance, etc. of cells and battery packs
3). Management of battery pack failures - sensor loss, cell failure, etc
3. The necessity and test method of BMS test.
BMS is a particularly complex electronic device. In its design phase, the functionality of the prototype needs to be verified; In the production phase, the functionality of the product needs to be tested; If the equipment fails, it needs to be serviced. These phases require the support of corresponding test equipment.
The functions of BMS involve a variety of technologies including data acquisition, data communication, process control, etc., which require a variety of ports and devices such as ADC, DIO, PWM, CAN, and relays, and the functions and algorithms are relatively complex. In order to comprehensively test (and in many cases perform and evaluate) these complex functions, there are two main approaches to testing:
1). Test through the physical object: the physical docking of the managed battery pack with the BMS for testing.
This test method is the most straightforward, and all the test parameters are consistent with the actual situation, which seems to be ideal, but there are still many problems in practical application, It will take a long time to charge and discharge the battery pack, and it will take a long time to wait in the test cycle, which is difficult to carry out batch testing.
2). Auxiliary equipment required: In order to simulate various environmental conditions, auxiliary equipment such as large incubators are required.
3). Difficulty in adjusting parameters: If it is used for the verification and debugging of a single function of the BMS, the state of the battery pack should be adjusted by charging and discharging before starting the experiment.
4). Poor controllability: important parameters such as the capacity and internal resistance of the monomer will be limited by the physical object, and there is no room for adjustment. Due to the influence of various factors such as the battery pack assembly process, it is impossible to adjust the SOC and other operating states of any single unit, and with the increase of the number of cycles, the battery pack itself will also change.
5). There are potential safety hazards: the battery pack itself is a device that stores a lot of energy, although this test method poses a threat to the personal safety of the tester.
6). High energy consumption: Charging and discharging the battery pack requires a lot of energy.
7). High system cost: The price of the battery pack itself is relatively high, especially for high-power battery packs, and the related maintenance costs are also relatively high.
8). Actual state unknown: the deadliest point. The voltage, temperature, and equalization current of each cell in the operation of the battery pack
