Auxiliary Power

⚠ 🛡️ The first stage: external detection and elimination of "open door killing" 1. Sniff and sweep: Without touching the cabinet, smell whether there is a slightly sweet smell of ethylene glycol antifreeze (leakage) or a pungent sour smell (electrolyte leakage). Use an infrared thermal imager to scan the cabinet to confirm that there is no local abnormal high temperature (smoldering). 2. Confirm external power outage: Confirm that the PCS DC line and 220V auxiliary power line outside the cabinet are physically disconnected. 3. Check the shell to prevent electric shock: Wear 1000V insulating gloves and insulating shoes, and use a multimeter to measure the voltage of the exposed metal part of the cabinet to the earth (confirm that the shell is not currently charged to prevent electric shock when opening the door). 4. Door opening operation: Stand on the hinge side of the cabinet door (explosion-proof position), turn sideways and slowly open the cabinet door. 💧 Phase 2: Internal mechanical structure and liquid cooling fatal injury investigation Goal: Confirm that there is no internal leakage or structural deformation without touching electricity. 1. Liquid cooling pipeline inspection: Use a strong light flashlight to focus on the black coolant pipe on the left side and the metal quick-plug connector with "√" on each battery drawer. Wipe the bottom of the connector with a dry paper towel to make sure there is absolutely no liquid leakage. (If there is liquid leakage, stop the operation immediately and determine that the insulation is damaged). 2. Explosion-proof valve inspection: Check the white round explosion-proof valves on the front of 5 drawers. It must be intact and flat. (If it breaks and pops off, the module is considered a thermal runaway hazard and will be scrapped directly). 3. Load-bearing structure inspection: Check the metal load-bearing tray and side slide rails at the bottom of each drawer. Confirm that there is no downward yielding bend. ⚡ The third stage: System-wide high-voltage blind test (overall insulation physical examination) Goal: Verify whether there is leakage inside the entire system under 832V series connection. 1. Find the test point: Never unplug the orange series wire on the right side of the drawer. Remove the white insulating cover of the high voltage control box at the bottom and locate the final pure copper busbars (BAT+ and BAT-) on the battery side of the main contactor. 2. Use a megger (megohmmeter): ◦ Measure the resistance of BAT+ to the cabinet ground bar (PE). ◦ Measure the resistance of BAT- to the cabinet ground bar (PE). 3. Judgment criteria: If the resistance value is > 2 MΩ, it proves that there is no leakage in the 5 drawers and the waterway. If < 2 MΩ, it proves that there is internal case leakage. Regardless of whether there is leakage or not, proceed to the next stage for physical voltage reduction. 🪚 The fourth stage: physical voltage reduction and [split battery in-depth inspection] (the link you require most) Goal: Neutralize 832V hazards and conduct an independent "sabotage" of each 166V drawer. 1. Release the series connection: Press the orange locks on the right side of the 5 drawers in sequence and unplug the high-voltage series connection plug. Put insulating caps on all metal pins. 2. Split insulation investigation (catch the leakage culprit): ◦ Use a megohmmeter (500V range) to conduct unit tests on the 1st to 5th drawers one by one. ◦ Action: Test the positive socket of a single drawer against the metal shell of the drawer; test the negative socket against the shell. ◦ Conclusion: Find drawers with resistance < 2MΩ, label them "Internally damaged", and remove them from the available list. 3. Split voltage measurement: Use a high-precision multimeter to measure the positive and negative voltages of the drawer with qualified insulation. Normally it should be around 166V. If the voltage of a drawer is abnormally low (for example, only 140V), it means that the drop caused physical disconnection of the internal battery core or a serious micro-short circuit. 4. Independent inspection of the high-voltage box: Check whether the ceramic relay in the bottom high-voltage box is cracked and whether the terminals are loose and fallen off. 💻 Stage 5: Weak current wake-up and BMS brain self-test Goal: Verify the communication and sensing neural network of the intact module. 1. Connect to auxiliary power: Make sure that all high voltages are disconnected, and then input 220V AC power to the switching power supply on the left side of the high voltage box. 2. Observe the local status: The door panel HMI screen lights up and observe whether a red historical alarm pops up immediately. 3. Connect the computer to read the underlying data: Connect the laptop to the debugging port: ◦ Look at the slave control board: Read the voltage of 52 cells of all qualified drawers. If the voltage of a certain cell displays garbled characters, it means that the drop has broken the sampling wire of the cell. ◦ Look at the temperature: Confirm that there are no abnormal readings of -40℃ or +150℃ (exclude the NTC probe from being broken). 4. Action test: The software issues a command to close the relay, listen for a crisp closing sound, and confirm that the mechanical action is normal.The logical chain this time: get rid of the illusion that "the shell is safe without electricity" -> open the door, check the water and check the structure -> test the insulation as a whole -> disassemble it into individual units and measure the insulation and voltage one by one -> finally use the auxiliary electricity to check the brain.