1. High voltage of power lithium-ion battery: After being fully charged and left to stand, the voltage of a single string or several strings of power lithium-ion batteries is significantly higher than normal, while the voltage of other individual cells is normal.
Causes of failure: ① Data acquisition error; ② Poor or malfunctioning LMU equalization function; ③ Low battery cell capacity, resulting in rapid voltage rise during charging.
Troubleshooting methods: ① If the displayed voltage value of a single cell is higher than that of the other cells, measure the actual voltage value of the cell and compare it. If the actual value is lower than the displayed value but the same as the voltage of the other cells, calibrate the LMU cell voltage according to the actual value; if the measured value matches the displayed value, manually discharge and equalize the single-cell lithium-ion battery. ② Check if the voltage sampling line is broken or has a loose connection; ③ Replace the LMU.
2. Low voltage of power lithium-ion battery: After being fully charged and left to stand, the voltage of one or several individual cells of the power lithium-ion battery is significantly lower than normal, while the voltage of other cells is normal.
Causes of failure: ① Data acquisition error; ② Poor or malfunctioning LMU equalization function; ③ High cell self-discharge rate; ④ Low cell capacity, resulting in rapid voltage drop during discharge.
Troubleshooting methods: ① If the displayed voltage value of a single cell is lower than that of the others, measure the actual voltage value of the cell and compare it. If the actual value is higher than the displayed value and the same as the voltage of the other cells, calibrate the LMU cell voltage according to the actual value; if the measured value matches the displayed value, manually perform charging equalization on the individual lithium-ion batteries. ② Check if the voltage sampling line is broken or has a loose connection; ③ Replace the LMU; ④ Replace the faulty lithium-ion battery pack.
