Spinel lithium titanate batteries are widely used for their excellent rate performances and cycle performances

but their flatulence problems severely constrain the development of the battery

especially at high temperatures.To solve the problems

three commercial lithium titanate soft package batteries were selected as the experimental objects

the charging and discharging tests were carried out under high temperature conditions

and the inflated volume of the battery was tested with the self-designed battery inflated volume test device.The results show when the capacity retention rate is 80%

the number one and number two batteries charge and discharge for 1 500 times

the number three battery charges and discharges for 1 000 times

and the corresponding battery flatulence rates are 43.05%

13.46%

and 46.55%.During the whole charge-discharge cycles

the flatulence rate of the batteries are fitted by certain scatters.The flatulence rate of the number one and number two batteries increases linearly

and the growth rate of the first battery is greater than that of the number two battery

and the number three battery is quadratic function growth.Through the analysis of the capacity decay rate and the flatulence rate of the battery

it is found that the decay rate of the battery increases with the increase of the flattening rate.The electrochemical impedance spectroscopy before and after the cycles shows that the higher the flatulence rate of battery is

the larger the ohmic impedance of the battery will be

which is a linear relation.As long as the flatulence rate of the batteries get to a certain extent

the electrochemical impedance of the battery will have a greater change and an upper limit of diffusion impedance exists with increase of flatulence rate of the batteries.