Local cell temperature monitoring for aluminum shell lithium-ion battery based on electrical resistance tomography

• An approach for local temperature monitoring of aluminum shell LIB was presented.
• A flexible sensor device for obtaining apparent resistivity of LIB was designed.
• Proposed formula of apparent resistivity, local temperature and residual capacity.
• Apparent resistivity has a nonlinear growth relationship with temperature of LIB.
• Internal temperature during transients deviates from surface temperature of LIB.

This paper presents an approach for the local the cell temperature monitoring of an aluminum shell lithium-ion battery cell by electrical resistance tomography, which has a great potential to analyze the correlation of apparent resistivity, local cell temperature and residual capacity. To determine this correlation, a flexible sensor was first designed, and the Wenner configuration was applied in the measurements. The investigated temperatures ranged from −20 °C to 70 °C. The results showed that the apparent resistivity had an exponentially increasing trend as the temperature increased. The effect of the residual capacity was further investigated. It is found that a lower residual capacity resulted in a lower apparent resistivity, which intensified as the temperature decreased. A comprehensive equation was developed to determine the local cell temperatures. Images of the apparent resistivity distribution under cell discharge further revealed the feasibility of the method. Finally, the proposed equation was applied to evaluate the cell core temperature which was compared with the surface temperatures from external sensors.