Fuzhou Fuguang Electronics Co., Ltd.

Quick Repair of Lithium Battery Pack in After-sales Maintenance

 Background 

To the electric vehicle, cruising ability is an important standard in measuring its value. As a key core component in the EV, the lithium-ion motive battery has a direct influence on performance of EV including cruising ability, safety, service life, charging time and temperature adaptability etc.

At present, the main problem we are facing in after-sales maintenance is the decline of motive battery range caused by improper daily use or lacking maintenance.

FUGUANG provides quick solutions to after-sales maintenance of the EV lithium battery pack. It can realize quick repair of lithium battery pack by accurately assessing SOH, matching battery modules for replacement and equalizing failed modules.

Quick Repair of Lithium Battery Pack in After-sales Maintenance

 Solutions 

FGCD Series Lithium Battery Discharge-Charge Unit

• Deep discharge to ensure SOH
• Test SOC of replacement battery modules to ensure equalization between modules
• Balance failed modules to maintain cells equalization
  
  
  
  
  

Step1: Accurately assess SOH¹, clear the fault

When complaint from final customer for low range battery pack is received, after-sales center should test SOH first so that other causes can be excluded. It helps to determine whether the battery pack is the real faut point.

FGCD series lithium battery discharge-charge unit first need to charge the battery module completely, so as to make sure that it is in the state of fully charged.

After charging, the tester automatically transforms into the mode of discharging.  By deep discharging, SOH can be confirmed. It can read data of all modules and cells via BMS system protocol.

Note 1. SOH: state of health, percentage of battery current capacity to its factory capacity

Step 2: confirm SOC² of replacement battery modules, ensure equalization between modules

For quick repair, after-sales center can directly use the spare module in stock to replace the faulty one. Before replacing, SOC of replacement should be tested.

FGCD series charges and discharges spare modules to make sure that SOC of replacement matches with other modules. FGCD can read data of all cells via BMU protocol.

Note 2. SOC: state of charge, percentage of battery remaining capacity

Step 3: Part of modules³ equalization, balance cell voltage

After-sales center needs to deal with the replaced failure modules. Problems of some modules are caused by cell imbalance which can be solved by LIFG equalization tester. LIFG takes advantage of present lines connecting every cell in battery modules to charge or discharge cells, in this way, voltage difference can be eliminated.

LIFG Equalization Tester

• Two-way charge and discharge equalization: equalization efficiency 2-3 times, solve the problem of capacity reduction caused by pseudo-fault. 
• Voltage Clamp: continue to work with a small current when the battery reaches the equalization target value to prevent voltage drop
• Directional Equalization: specify any single-channel or multiple-channel cell to work independently

• The repaired module can be re-connected to the battery pack or used as a spare module for the next repair.

Note 3. modules: The after-sales center generally does not deal with failed modules which are not caused by voltage difference. Such kind of problem involves disassembling modules and replacing cells, etc. The cells in modules are usually welded together. If manually disassembled and welded improperly, they may cause battery thermal runaway.

Step 4: Discharge before sending back, ensure safe transportation

When the after-sales center needs to send the repaired battery pack back to the user, battery pack needs to be set in low power for the safety in long-distance transportation.

To meet transportation safety standard, FGCD can be used to discharge the battery pack again.

 END 

FUGUANG provides a full set of intelligent maintenance equipment and perfect solutions to motive lithium battery testing and maintenance. Comprehensively improve the quality and efficiency of testing services, ensure the safety, cruising ability and service life of lithium batteries, and provide a good service experience for users at all stages of lithium battery applications!