Battery Performance Testing | A Complete Guide to Lithium-Ion Battery Storage Performance Testing
In routine storage and practical applications, lithium-ion batteries often face a variety of environmental and external challenges. Room-temperature storage, high-temperature storage, and shell stress testing are the key verification procedures to address these challenges.
The room-temperature storage test focuses on the battery’s ability to maintain performance under normal storage conditions and concerns the reliability of long-term storage; the high-temperature storage test targets storage scenarios in hot environments or after sustained operation and verifies the battery’s resistance to thermal degradation; the shell stress test evaluates mechanical external impacts on the battery under high-temperature conditions and is an important item to ensure the structural integrity of the battery casing in specific environments.
Together, these three tests provide early validation of storage stability and structural safety across the battery’s life cycle and constitute an essential foundation for evaluating battery quality.
1、Overview of Battery Storage Test Items
| No. | Test Item | Test Purpose | Acceptance Criteria |
|---|---|---|---|
|
1 |
Room-Temperature Storage Test |
Evaluate capacity fade during long-term storage at room temperature |
Per specification standards. |
|
2 |
High-Temperature Storage Test |
Evaluate capacity fade during long-term storage at high temperature |
Per specification standards. |
|
3 |
Shell Stress Test |
Verify the mechanical/sealing robustness of the battery casing at 70 °C |
No casing cracks/no mechanical damage; no fire, no explosion. |
2、Detailed Explanations of Storage Performance Test Items
2.1 Room-Temperature Storage Test
Test Purpose:
Simulate the condition of a cell or battery stored at room temperature.
Test Steps:
① Initial capacity test: use a 0.5C current to test the initial capacity at room temperature;
② Prepare batteries: prepare two groups of cells or batteries, with states of charge being fully charged and half charged, respectively;
③ Measure the cell or battery voltage, impedance, and thickness;
④ Storage conditions: store the cell or battery for the required time T under the following environmental conditions:
Temperature: 23 ± 5 °C Relative Humidity: 65 ± 20% RH
⑤ After the specified storage time, measure voltage, impedance, and thickness;
⑥ Remaining capacity test: use a 0.5C current to test the remaining capacity and recovery capacity at room temperature.
Judgment Criteria:
Execute according to the requirements in Table 1.
Table 1 Storage Time and Performance Requirements
Fully charged: Charge at 0.5C constant current to 4.2 V, then switch to constant voltage charging until the current drops to 0.05C; stop charging.
Half charged: After fully charging at 0.5C, discharge at 0.5C for 30 min.
2.2 High-Temperature Storage Test
Test Purpose:
Simulate the condition of a cell stored at high temperature.
Test Steps:
① Initial capacity test: test the initial capacity at room temperature with a 0.5C current;
② Fully charge: at room temperature, fully charge the sample at 0.5C;
③ Rest: after resting for 1 h, measure the pre-test voltage, impedance, and thickness, then place the sample into a high-temperature chamber set to the required temperature;
④ Record time and monitor temperature: record the start time and, during the test, monitor the actual chamber temperature with a thermometer;
⑤ Storage: after the required storage time T, measure the cell/battery thickness in the high-temperature chamber, then remove the sample;
⑥ Rest: after resting for 1 h, measure the post-test voltage and impedance;
⑦ Remaining capacity test: at room temperature, test the remaining capacity and capacity retention with a 0.5C current.
Judgment Criteria:
Execute according to the requirements in Table 2.
Table 2 Test Items, Parameters, and Evaluation Criteria
2.3 Shell Stress Test
Test Purpose:
Verify the performance of the battery casing under high-temperature conditions.
Test Steps:
① Fully charge: at room temperature, fully charge the sample at 0.5C;
② Measurement: measure the pre-test voltage, impedance, and thickness, then place the sample into a high-temperature chamber set to 70 °C;
③ Record time and monitor temperature: record the start time and, during the test, monitor the actual chamber temperature with a thermometer;
④ Storage: after 7 h of testing, remove the sample;
⑤ Observation: observe the battery appearance.
Judgment Criteria:
a) The battery casing has no physical cracks and no signs of mechanical damage; internal components are not visible from outside the battery;
b) The sample shall not explode and shall not ignite.
Figure 1 Finished Battery Under High-Temperature Shell Stress Test
3、Referenced Standards and Applicable Specifications
The above battery storage performance tests are carried out with reference to the following industry standards:
- UL1642
- UL2054
- IEC62133
- GB/T 18287
- UN38.3
- Certain customer-specific standards
4、Summary and Recommendations
The above three tests together construct a performance and safety verification system for lithium-ion batteries from different perspectives. Room-temperature and high-temperature storage tests respectively cover conventional and extreme storage scenarios, revealing rules of change such as capacity retention and self-discharge; the shell stress test focuses on high-temperature environments and verifies, from a structural perspective, the casing’s resistance to compression and impact. The three form a complementary verification of function and structure.
The test procedures center on “scenario simulation – dynamic monitoring – data recording,” ensuring result reliability through precise control of test conditions and real-time parameter acquisition. Clear acceptance criteria provide quantitative benchmarks for the tests, not only ensuring stable application of batteries in real-world scenarios but also offering key data references for structural optimization and material upgrades.
