Causes of Problems with Electric Vehicle Charging Cable Connections

China [CN]

Content: Broken core wires or poor contact within the cable can cause intermittent charging. Frequent bending, excessive pulling on the cable, or oxidation and corrosion of the metal conductors after long-term use can also cause this problem. Additionally, a loose connection between the cable plug and the charging station or vehicle interface can cause unstable contact. Try replacing the plug or the entire cable and standardizing usage habits.

Description: Frequent charging interruptions with an electric vehicle charging cable require a multi-faceted analysis of the cause, including hardware contact, communication protocol, and safety protection. The following is an analysis of the core issues:

1. Abnormal Charging Interface Contact

Foreign matter or oxidation interference: Dust and moisture accumulate in the charging cable plug (such as the GB/T 20234 interface) or the vehicle charging port, leading to poor contact on the CC (Charging Connection Confirmation)/CP (Control Pilot) signal lines. Oxidation of the copper terminals increases contact resistance, triggering a communication timeout.

Mechanical structural failure: A stuck locking mechanism (such as an incomplete electronic lock), a deformed interface spring, or a worn charging cable plug can cause an unstable physical connection and instantaneous disconnection of the high-voltage circuit. 2. Communication Protocol Handshake Failure

Protocol compatibility issue: The charging protocol supported by the charging pile and the vehicle does not match (e.g., CCS, GB/T, or CHAdeMO standards conflict). Failure to reach consensus on parameters (e.g., maximum current and voltage) during the handshake phase leads to charging initialization failure.

Signal transmission failure: Poor contact on the CAN bus signal lines (e.g., CAN_H/CAN_L in a fast-charging cable) or electromagnetic interference (e.g., nearby equipment with strong magnetic fields) interrupts charging status data transmission, causing the BMS (Battery Management System) to automatically disconnect the power supply.

3. Overheating or overcurrent protection triggering

Cable or connector overheating: Prolonged fast charging causes the cable's internal resistance to heat up (>60°C), triggering the charging pile's built-in temperature sensor to trigger overheat protection. Poor connector contact can cause arcing, leading to a sudden increase in local temperature that is detected by the BMS.

Abnormal current fluctuation: A battery module failure (e.g., cell voltage imbalance) causes a sudden change in charging current, exceeding the charging pile's current limit threshold, causing the system to automatically initiate disconnection protection. 4. Battery Management System (BMS) Abnormality

Battery Status Lock: When the battery temperature is below 0°C or above 50°C, the BMS activates thermal management priority mode and suspends charging. If the remaining capacity (SOC) display is abnormal or the battery health (SOH) falls below the threshold, the system prohibits charging to avoid risks.

Software Logic Error: The vehicle system firmware version is too low, and there is a vulnerability in the charging control logic, which may misjudge "full charge" or "fault state" and prematurely terminate the charge.

5. External Environment and Power Supply Interference

Voltage Fluctuation Exceeds Limits: Grid voltage instability (e.g., below 200V or above 250V) causes the voltage regulator in the charging pile to fail to maintain its normal operating range, triggering undervoltage/overvoltage protection.

Extreme Weather Impacts: Heavy rain causing water to enter the charging connector and short-circuit, strong winds causing the charging pile to shake and pull the cable, or ice forming on the connector in winter that prevents the physical connection, can all cause interruptions. Troubleshooting Recommendations: Prioritize checking the cleanliness and lock status of the connectors. Replace the charging station to test compatibility. Check the charging log (such as fault codes P1550 and P1551) on the vehicle's display and, if necessary, use a diagnostic tool to read the BMS data. If hardware damage (such as deformed reeds or broken cables) is present, contact a professional for inspection and avoid disassembling high-voltage components yourself.

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