Common problems analysis and solution for lithium battery
With the high-speed development of science and technology level. The lithium battery are widely used in our daily life, but accident of lithium-ion batteries always emerge in endlessly, which is upset us, here we special summarize some common problems which lithium ion battery usually happens and the solutions, hope can give us some help.
1. The voltage different, some are lower
a) Self-discharge caused low voltage: The lithium battery cell self-discharge large, which makes its voltage drop fast. Solution: The lower voltage battery we can store it first and testing to avoid the lower voltage one.
b) Charged inequality caused low voltage: After Battery testing and then charged, because the contact resistance or test tank inconsistent which caused charge inequality. Stored in a short time (12 hours) to measure the voltage difference is small, but when long stored voltage difference is bigger, Solution: the low voltage has no quality problem, can be solved by charging. In production for over 24 hours after charged voltage measurement.
2. Internal resistance is larger
a) Caused by different testing equipment: if the equipment testing accuracy is not enough or can not eliminate contacting resistance, will cause internal resistance is larger. Solution: Principle of ac bridge method should be adopted to test resistance testing instrument.
b) storage time is too long: lithium battery storage too long will capacity loss, internal inactivation and Internal resistance become larger. Solution: could be solved by charge and discharge.
c) Caused by abnormal heat: During the cell processing(spot welding and ultrasonic wave) makes the battery heat, makes the film close up, and lead the Internal resistance become larger.
3. Lithium battery expansion
a) Lithium battery expansion during charging: when battery is charging, the lithium battery will Expansion of natural, but usually not over 0.1mm. but if overcharge will cause the electrolyte decomposition, Internal pressure increases, and will case lithium battery expansion.
b) Lithium battery expansion during processing: usually abnormal processing( such as short circuit, too heat) will cause excessive internal heat decomposition of the electrolyte and case lithium battery expansion.
c) Lithium battery expansion during cycling: when lithium battery during cycling, the thickness will be increased by the Cycle number increases, but after 50 weeks times basically will not increased, usually increased 0.3~0.6mm, This phenomenon belongs to normal cell reaction. But if increase cell thickness or Inflation may be appropriately reduced by reduce the internal material.