Smaller, Lighter and Higher-output Lithium Ion Battery System for Series Hybrid Shinji Ota Jun Asakura Shingo Tode 24 ICECU Electronic Control Unit46 16 We have developed a lithium-ion battery system with excellent charge-discharge performance achieving low fuel consumption of hybrid vehicles. It has been essential to achieve components to be drastically smaller and with higher performance, to develop a smaller, lighter and high-output battery system installable in the space under the driver s seat, required by vehicle manufacturers. The development has achieved a 24 %-smaller-in-height lithium-ion battery cell with higher output, 46 %-smaller battery Electronic Control Unit (ECU) by development of dedicated IC for battery controls, 16%-lighter battery system by replacing chassis materials with plastics and with application of new technology of welding different metals to the connection of cells, and so on. These developments made it possible to install the battery system under the driver s seat, which has never been believed possible to this point. Consequently, the space behind the rear seat where the battery system was usually installed can be secured for another application, which contributes to a larger interior space of the vehicle. This added value has succeeded in achieving a vehicle sales volume above the manufacturer s target. ZEV Zero Emission VehicleNEV New Energy Vehicle HEV Hybrid Electric VehiclePHEV Plug-in HEVEV Electric Vehicle 20201200 [1] HEV2 HEV 3 IC 2 IC ECU CAE
132 10 40 % Correlation between energy density and power density Ragone plot Cell design Comparison of conventional and development models 12.5 120.0 85.0 12.5 120.0 65.0 128 100 % 98 76 % 5.5 5.0 157 186 6600 6600 20 % 10 % 15 % 3 %
133 Correlation between specific surface area and power/tap density Conceptual figure about conductive path ECU ECUECU MPU Micro Processer Unit ECU 1 Block diagram of the battery system 70 kwhev 400 V ECU ECU 70 50 ECU ASIC Application Specific Integrated Circuit IC ASIC ECU ASIC ASIC ASIC 1ASIC ASIC IC ASIC Comparison of dedicated ICs ASICs 10 20 50 mv 3 mv 1 0.36
134 ASIC 5 V 1020 ASIC ASIC ASIC 1 64 3 ASIC 10 ECU ECU ASIC 50 46 42 ECU 72 ECU ECU Evolution of the battery ECU 72 80 3536 1758 1860 1007 527 308 1 0.28 10 20 1 ECU 18 12 Exploded view of conventional and development battery system ECU Overviews of the battery ECU / Comparison between conventional model, target model and development model 41580 33960 18 % 33660 20 % 51.4 45.0 42.8 12 % 16 %
135 2 1836 cm 3 3.7 %320 g 0.6 % 1/5 1/10 2142cm 3 5.2 % 344 g 0.7 % Method of screwing 1.6 mm 2 mm590 MPa 1200 MPa 2.6 kg 5.1 %CAE Comparison between conventional model of clad busbar design and development welding busbar design CAE Result of CAE for this development
136 1.2 mm 2 mm 4.2 kg 8.2 % IC ASIC 24 %2 IC ASIC ECU ASIC 46 % 8.6 kg 16 %20 % - HEV PHEV BEV & Automotive Energy Business Div., Sanyo Electric Co., Ltd., Automotive & Industrial Systemes Company & Automotive Energy Business Div., Sanyo Electric Co., Ltd., Automotive & Industrial Systemes Company & Automotive Energy Business Div., Sanyo Electric Co., Ltd., Automotive & Industrial Systemes Company [1], 2017, p.51, May, 2014.