The leakage protection technology of lithium battery packs mainly achieves rapid response by real-time monitoring of abnormal current or voltage changes between the battery pack and external circuits, combined with hardware circuits and software control. Its core principle is as follows:

Insulation testing and voltage monitoring

Insulation resistance monitoring: Through a high-precision voltage sampling circuit, the insulation resistance between the positive and negative terminals of the battery pack and the casing (or ground wire) is continuously monitored. When the insulation resistance is lower than the safety threshold (such as several hundred kilohms), the system determines it as leakage.

Voltage differential detection: A differential amplifier is used to collect the voltage difference between the positive and negative terminals of the battery pack and ground. If the difference exceeds the set range (such as ±50mV), a leakage alarm will be triggered.

2. Hardware protection mechanism

Leakage detection chip: A dedicated chip (such as an integrated operational amplifier and comparator) analyzes the voltage signal in real time and outputs a control signal when an abnormality is detected.

Relay or MOSFET switch: After receiving the signal from the detection chip, it quickly disconnects the battery pack from the load to prevent continuous leakage.

3. Software Control and Diagnosis

Threshold setting and delay processing: The software presets the leakage threshold and incorporates a delay mechanism (such as triggering protection only when an abnormal signal lasts for 100ms) to prevent false alarms.

Fault recording and reporting: Record the time, voltage value and other information of leakage events, and report it to the upper-level system through communication interfaces (such as CAN bus).

4. Self-checking and redundant design

Regular self-check: The system regularly simulates leakage signals to verify whether the detection circuit and protection functions are normal.

Dual detection: Independent hardware circuits and software algorithms are used to monitor leakage separately. Protection is triggered only when the results of both are consistent.

5. Recovery mechanism

Manual/Automatic reset: After the leakage fault is eliminated, the protection circuit needs to be reset through a manual button or software command, and the battery pack should be reconnected.

Insulation recovery detection: Before resetting, the system will retest the insulation resistance. Power supply restoration is only allowed after it is confirmed to be safe.

6. Temperature and humidity compensation

Environmental factor correction: In a high-temperature and high-humidity environment, the insulation resistance may decrease. The system dynamically adjusts the leakage threshold through a temperature sensor to ensure protection sensitivity.

7. Electromagnetic Compatibility (EMC) design

Filter circuit: An RC filter is added to the detection circuit to suppress the influence of electromagnetic interference on voltage sampling.

Shielding and grounding: Optimize the circuit board layout to reduce the interference of external electromagnetic fields on leakage detection.