With the wide application of lithium batteries in new energy vehicles, energy storage systems, consumer electronics and other fields, their safety performance has become a core concern of the industry. The safety testing of lithium batteries not only involves the optimization of materials and processes, but also requires a series of harsh experiments to verify their stability under different extreme conditions. This paper combines domestic and international standards and actual cases to systematically analyze the key technologies and future development direction of lithium battery safety testing.
I. Core items of lithium battery safety testing
Lithium battery safety testing aims to simulate the physical, chemical and environmental risks in real scenarios to ensure that it does not catch fire or explode under abnormal conditions. The following are the current mainstream test items and methods:
1.Thermal Abuse Test
Purpose: To evaluate the thermal stability of the battery in a high temperature environment.
Method: The fully charged battery is heated up to 130°C at a rate of 5°C/min and kept at a constant temperature for 30 minutes to observe whether thermal runaway occurs.
2. Short circuit test
Purpose: To simulate the risk of internal or external short circuit of the battery.
Method: In a 55℃ environment, short-circuit the positive and negative terminals of the battery with wires of resistance ≤50mΩ, and monitor the surface temperature (not exceeding 140℃) and whether it catches fire and explodes.
3. Mechanical damage test
Puncture test: Puncture the battery with a 3mm diameter steel needle to verify its puncture resistance.
Squeeze test: Apply 13±1KN squeeze pressure (through a 32mm steel rod) to test the compression resistance of the battery structure.
Heavy impact test: A 9.1kg weight is dropped freely from a height of 610mm to hit the battery, simulating the impact of an accidental fall.
4. Overcharge/overdischarge test
Overcharge test: Charge the battery at 3C times to 1.5 times the rated voltage (e.g. 10V overcharge), observe whether the battery suffers from thermal runaway or electrolyte leakage.
Forced Discharge Test: Connect the external power supply in series for forced discharge to evaluate the safety of the battery under abnormal discharge condition.
5. Environmental adaptability test
Low air pressure test: Simulate high altitude environment (e.g. 11.6kPa, corresponding to an altitude of 15,240 meters) to test the sealing of the battery and the risk of gas release.
Temperature cycling test: Verify the stability of the battery under extreme temperature by cycling changes from -40℃ to 60℃.
II. Relevance and challenges of security testing
1. Accident case analysis
Short circuit and overcharging risk: Statistics show that 68% of lithium battery fires are triggered by short circuits and 15% by improper charging and discharging.
Chain reaction of thermal runaway: In a neighborhood fire in Nanjing, the thermal runaway of the battery triggered the “chimney effect”, resulting in 15 deaths, highlighting the need for battery safety design.
2. Limitations of testing technology
Insufficient coverage of dynamic scenarios: Existing tests are mostly static experiments, making it difficult to simulate complex scenarios such as vehicle collisions and thermal spreading of energy storage systems.
Challenges of new batteries: the emergence of new technologies such as solid-state batteries and sodium-ion batteries requires the development of adapted test methods.
Post time: Mar-06-2025