Sensorless battery internal temperature estimation using a Kalman filter with impedance measurement

Journal article

This study presents a method of estimating battery cell core and surface temperature using a thermal model coupled with electrical impedance measurement, rather than using direct surface temperature measurements. This is advantageous over previous methods of estimating temperature from impedance, which only estimate the average internal temperature. The performance of the method is demonstrated experimentally on a 2.3 Ah lithium-ion iron phosphate cell fitted with surface and core thermocouples for validation. An extended Kalman filter, consisting of a reduced order thermal model coupled with current, voltage and impedance measurements, is shown to accurately predict core and surface temperatures for a current excitation profile based on a vehicle drive cycle. A dual extended Kalman filter (DEKF) based on the same thermal model and impedance measurement input is capable of estimating the convection coefficient at the cell surface when the latter is unknown. The performance of the DEKF using impedance as the measurement input is comparable to an equivalent dual Kalman filter using a conventional surface temperature sensor as measurement input.

Authors: Richardson, R; Howey, D

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Institute of Electrical Engineers
• Journal: IEEE Transactions on Sustainable Energy
• Volume: 6
• Issue: 4
• Pages: 1190-1199
• Publication date: 2015-01-25
• DOI: 10.1109/TSTE.2015.2420375
• EISSN: 1949-3037
• ISSN: 1949-3029
• Keywords: temperature sensors; state estimation; vehicle drive cycle; core thermocouples; dual-extended Kalman filter; lithium-ion battery; current excitation profile; cell surface; lithium-ion iron phosphate cell; secondary cells; batteries; DEKF; thermal model; 93; surface temperature estimation; thermocouples; surface thermocouples; impedance; electrical impedance measurement; battery charge measurement; cs.SY; temperature measurement; Kalman filter; temperature; Kalman filters; reduced-order thermal model; impedance measurement; battery cell core estimation; convection coefficient