Common Causes of Lithium Battery Failure and Countermeasures for Specific Failures

Lithium battery failure is usually the result of multiple layers of elements. Only by addressing multiple aspects from materials, processes, design to testing and management can the failure rate be systematically reduced.The following will list common failure types, cause analysis and corresponding prevention or improvement measures. I hope it will be helpful to everyone!

(1) Abnormal capacity attenuation
Common manifestations: fewer cycles.
Main causes: collapse of the positive electrode material structure, instability of the SEI film, decomposition of the electrolyte, etc.

(2) Increased internal resistance
Main manifestations: decreased discharge rate capability and severe heat generation.
Main causes: thickening of the SEI film, degradation of the conductive network, and corrosion of the current collector.

(3) Expansion and deformation
Common manifestations: expansion or even rupture of the battery shell.
Main causes: gas production due to decomposition of the electrolyte and piercing of the diaphragm by lithium dendrites at the negative electrode.

(4) Internal short circuit
Common manifestations: rapid self-discharge of the battery and, in severe cases, fire.
Main causes: lithium dendrites piercing the diaphragm, burrs on the edge of the grade, and welding defects.

(5) Overheating or fire
Common manifestations: continuous temperature increase accompanied by gas release.
Main causes: overcharge, over-discharge, external short circuit, thermal runaway.

(6) Abnormal voltage
Common manifestations: low open circuit voltage, incomplete charging or discharging.
Main reasons: poor telecommunication consistency, protection circuit failure, and active material failure.

(7) Accelerated self-discharge
Common manifestations: Rapid capacity drop during battery storage.
Main reasons: electrolyte side reaction, micro short circuit, and poor packaging.

(1) Problems with positive electrode materials
Unstable structure and Mn precipitation (such as high nickel content in ternary materials).
Measures: Optimize the positive electrode material ratio and coating process; strictly control the sintering temperature and oxygen atmosphere.

(2) Problems with negative electrode materials
SEI film is unstable, leading to lithium dendrite growth.
Measures: Use coated graphite or doped materials; optimize the first charging strategy (form stable SEI).

(3) Problems with electrolyte
High-temperature decomposition, viscosity change, decomposition gas production.
Measures: Select high-temperature stability additives; ensure consistent filling volume and good sealing.

(4) Problems with diaphragm
Uneven pore size or thermal shrinkage leads to short circuit.
Measures: Use three-layer composite diaphragm (PP/PE/PP); add thermal shutdown protection function.

(5) Problems with manufacturing process
Uneven coating, winding offset, and welding cold solder joints.
Measures: Improve coating accuracy and winding consistency; strengthen welding process quality control and AOI inspection.

(6) Problems with BMS (battery management system)
Overcharge and undervoltage protection failure.
Measures: Enhance software redundancy protection; regularly calibrate voltage sampling accuracy.