The New High Power Design of 8Ah Li-ion Battery for HEV Application

Researchers at The Industrial Technology Research Institute (ITRI) have developed a new 8Ah prismatic lithium battery cell with high current charge and discharge capability for use in hybrid electric systems applications. When 40 cells are combined in series, the system is capable of producing 144V which can be boosted up to 288V by using a high power DC-DC converter. The design results in (1) lower manufacturing and operating costs, (2) improved safety characteristics, (3) improved heat dissipation, and (4) improved battery management.
Particular emphasis have been given to enhancing both discharge and charge performance of the cell by optimizing material selection and structure to lower the internal resistance of the system, thereby improving both performance and safety characteristics for the single cell. By carefully tuning the design of both electrodes, this second generation cell can provide 300A of continuous discharge current while maintaining the ability to meet the minimum requirement for pulse power characteristics. This provides 625W of discharge power and the ability to accept 500W of regenerative power when the system is operated with the State of Charge (SoC) between 50 and 70%. The cell has also been designed to meet the abusive physical requirements associated with hybrid vehicle applications.
This paper highlights system requirements, describes the research and development process, and provides experimental test results for the 8Ah cell. The battery module design is also described.