In the vehicle-mounted rechargeable energy storage system, it is stipulated that the BMS needs to perform insulation detection on the integrated state of all components of the power battery system (cells, high-voltage components, housings, and wiring harnesses, etc.), and the insulation resistance value is used to measure the insulation state. It must be ensured that the ratio of insulation resistance and rated voltage between all conductive parts and each battery electrode is greater than 500Ω/V, that is, insulation resistance (Ri ≥ (Vb * 500 Ω/V). Below the value, a DTC (high voltage insulation abnormality) is stored, and a warning light is displayed on the combination meter to inform the driver of the abnormal situation.