A battery management system (BMS) is an electronic device that monitors and manages a lithium iron phosphate (LiFePO4 or LFP) battery pack. The BMS ensures that the battery is charged and discharged within safe limits and prevents overcharging, over-discharging, and short-circuiting. It also monitors the individual cells in the battery pack to ensure that they are balanced and functioning properly. A BMS can also provide information such as the battery’s voltage, current, and temperature, which can be useful for monitoring the battery’s health and performance. Some BMS also have built in protection functions like over current protection,over temperature protection,over charge protection and etc. The BMS can be either inbuilt or external to the battery pack.
Let’s first understand the components of the Lifepo4 battery, all Lifepo4 batteries in the market are composed of battery cells, BMS. The battery cell determines the lifespan and stability of the lifepo4 battery. The key indexes are determined by battery cell, such as cycle times, charging and discharging performance, etc. But the battery cell is open, if it is used in excess of the performance, it will only damage the life of the cell, so Lifepo4 battery must add BMS, BMS is a battery manage system. It manages the cell, controls its charging and discharging current, and limits or shuts down its use in a high and low-temperature environment so that the Lifepo4 battery can reach the best condition and the longest life. The BMS is the battery management system. Let’s talk about the specific indexes of the battery cell and BMS.
Battery Cell: Higee 120Ah battery cell
- nominal capacity: 120Ah, representing the actual capacity of your battery pack.
- Nominal voltage: 3.2V, representing the type of battery, it is worth noting that the ternary lithium battery is 3.7V.
- battery internal resistance: ≤ 0.3mΩ, technical parameters, representing the consistency of the battery, the consistency of a good battery cell in series represents the life of the battery.
- standard charging current: 1C, key information, many old batteries can not reach 1C, or marked 0.5C or lower.
- standard discharge current: 1C, key information, many old batteries can not reach 1C, or marked 0.5C or lower. 6. maximum continuous discharge current: 1C, key information, many old batteries can not reach 1C, or marked 0.5C or lower.
- Maximum continuous discharge current: 2C, key information, many old batteries can not reach 1C, or are marked 0.5C or lower.
- Peak discharge current: 3C, key information, many old batteries can not reach 1C, or are marked 0.5C or lower.
- Peak charge current: 2C, critical information, many old batteries can not reach 1C, or are marked 0.5C or lower.
- Operating voltage range: 2.5V-3.65V, representing the depth of charge and discharge of your battery, whether it reaches the designed capacity value.
- Operating temperature: charging state 0-50°C, discharging state -20-55°C. Represents the performance of the battery in high and low temperatures.
- cycle times: 1C ≥ 5000 times, 0.5C ≥ 5500 times, representing the life of the battery.
These 11 standards are very important. It is the basic information to judge the performance of lithium batteries.
BMS is the core of the whole battery, it is responsible for managing all the information in the battery cell. No matter whether you are using any brand of Li-ion battery cells, there will be individual differences, and the BMS is responsible for detecting the voltage, temperature, etc. of each cell. A qualified BMS needs to have an automatic equalization function in addition to detecting individual differences. When a cell is found to be too high or too low, the cell will be charged and discharged individually to keep it in line with other cells.
In addition to managing the voltage of each cell, it also needs to detect the temperature of the battery during charging and discharging; usually, there are four cell sampling points in a battery pack to sample the temperature of the whole battery, and it also monitors the temperature of the Mosfet on the BMS PCB and the ambient temperature; when the abnormal temperature is found, it will stop the output or disconnect the charger. It makes users safer when using Li-ion batteries and increases the life of Li-ion batteries at the same time.
In addition to voltage and temperature detection, the BMS also needs to have a very large number of protection functions, in addition to some conventional protection, it also needs to have the function of detecting whether the internal connection line is normal. CNBOU’s BMS has Single Cell Over Voltage, Single Cell Over Voltage Protection, and Single Cell Low Voltage Protection in CELL Infor.
Single Cell Low Voltage
Single Cell Low Voltage Protection
Battery Over Voltage
Battery Over Voltage Protection
Battery Low Voltage
Battery Low Voltage Protection
Also available are:
Voltage Sensing Failure
Temp Sensing Failure
Current Sensing Failure
Cell Different Pressure Failure
Charge Switch Failure
Discharge Switch Failure
Current Limit Switch Failure
Charge Over Temp
Charge Over Temp Protection
Charge Low Temp
Charge Low Temp Protection
Discharge Over Temp
Discharge Over Temp Protection
Discharge Low Temp
Discharge Low Temp Protection
Charge Over Current
Charge Over Current Protection
Discharge Over Current
Discharge Over Current Protection
Transient Over Current Protection
Output Short Circuit Protection
Transient Over Current Lock
Transient Short Circuit Lock
CNBOU’s LFP.6144 lithium battery is equipped with a touchable LCD screen, which not only displays all the warning and protection information but also allows you to select the protocol of communication with the inverter directly on the screen, supporting CAN and Modbus. It solves the problem that the user has to go through the computer software to select the communication protocol.
The most important thing for LiFePO4 battery BMS is the compatibility with inverter brands, which is very important for wholesalers and EPCs, and CNBOU’s LFP.6144 supports the current mainstream inverter communication protocols, with 27 communication protocols in 23 pins, covering almost all inverter communication protocols, and we are still in the process of updating and adding.