Overcharge Overdischarge Test
Overcharge test:
Overcharge test is a type of electrical abuse test where a cell is charged above 100% state of charge (SOC). The purpose is to see how the cell responds to excessive charging and help prevent dangerous reactions to be overcharged should they occur. It helps electrochemist determine the safety, longevity, and reliability of batteries when exposed to extreme charging conditions. In addition, it helps cell designers design CID or other preventive measures to ensure that conditions that could overcharge the cell occur, the cell will prevent itself from reaching a dangerous state.
Test Procedure:
- According to Sandia standard 6925, the test should be conducted starting at 100% SOC.
- The cell is charged with a constant current charging the cell and end when one of the following conditions is met:
- Hazard safety level (HSL) is 5 or greater (caught fire) or the cell reaches 250% SOC.
Overdischarge test:
Overdischarge test is a type of electrical abuse test where a cell is discharged intentionally beyond its recommended value. The purpose is to see how the cell responds to excessive discharging and if the cell can protect itself from damage under these conditions. It helps electrochemist determine the safety, longevity, and reliability of batteries when exposed to extreme discharging conditions. In addition, it helps cell designers design preventive measures to ensure that conditions that could overdischarge the cell occur, the cell will prevent itself from reaching a dangerous state.
Test Procedure:
- According to Sandia standard 6925, the test should be conducted starting at 100% SOC.
- The cell is then discharged and the test ends when one of the following conditions is met:
- HSL is 5 or more (caught fire), the test has gone on for 1.5 hours, or all subassemblies achieve voltage reversal for 15 minutes.
Standards:
SANDIA 6925 followed here. Similar standards IEC 62133, UL1642, SAE J2464, UN38.3, AIS-048 also have overcharge and overdischarge safety test requirements.
Equipment used:
Inhouse BSI setup to perform Overcharge / Overdischarge test
Sample Test:
Lithium-ion pouch cells were subjected to electrical characterization to determine the effects of overcharging and overdischarging. The test protocol for both tests includes continuous monitoring of cell voltage, temperature, and applied current throughout the test.
For the overcharge test, cell temperature and voltage vs. time as well as cell voltage, SOC, and current vs. time are shown in the accompanying plots, with corresponding quantitative data summarized in the tables below.
Sample Overcharge Plot:
Figure 1: Overcharge test - Cell temperature and Voltage vs. time
Figure 2: Overcharge test - Cell voltage, SOC, and Current vs. time
Sample Test Result:
| Cell ID | SOC at End (%) | Applied Current (Amp) | Wt. Loss (%) | Temperature Rise(⁰C) | Average T Rise (⁰C) | Peak Voltage (V) | Final Voltage After 24 h Rest, V | HSL | Description | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lithium-ion Pouch Cell | 271.83 | 6.79 | 0.11 |
|
54.6 | 4.104 | 0.240 | 2 | Cell swelled although No sign of leak, smoke, fire. Cell lost functionality |
Sample Overdischarge Test:
For the overdischarge test, cell temperature and voltage vs. time as well as cell voltage, and current vs. time are shown in the accompanying plots, with corresponding quantitative data summarized in the tables below.
Sample Overdischarge Plot:
Figure 3: Overdischarge test - Cell temperature and Voltage vs. time
Figure 4: Overdischarge test - Cell voltage, SOC, and Current vs. time
Sample Overdischarge Result:
Table 2: Overdischarge Test result
| Cell ID | Discharge SOC at End (%) | Applied Current (Amp) | Wt. Loss (%) | Peak Temperature (⁰C) | Average Peak T (⁰C) | Cell Voltage at End of Test (V) | Final Voltage After 24 h Rest, V | HSL | Description | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lithium-ion Pouch Cell | -113.02 | -6.184 | 0.01 |
|
51.15 | 0.665 | 2.132 | 2 | No sign of leak, smoke, fire. Cell lost functionality. |
FAQ:
1. What is Battery electrical Abuse Testing?
Electrical abuse testing evaluates how a battery (cell, module, or pack) behaves when it is subjected to electrical conditions outside its normal operating limits.
The goal is to identify safety hazards (thermal runaway, fire, venting, explosion, leakage) when the battery is electrically overstressed.
2. Why is it performed?
- Ensure compliance with safety standards (IEC 62133, UL 2580, UL1642, SAE J2464, UN38.3, AIS-048 etc.).
- Understand failure modes under misuse.
- Support pack design (protection circuits, fuses, current interruption devices).
- Reduce risks during charging, transport, and consumer use.
3. What are the test outcomes?
- Cell/module/pack voltage, current, and surface temperature.
- Onset of venting, smoke, or fire.
- Whether protective devices activated (CID, PTC, BMS cutoff).
- Post-test condition (capacity loss, swelling, leakage, rupture).
4. Who needs to do overcharge and overdischarge test?
