Thermal analysis and modeling of a notebook computer battery

Thermal performance of an intelligent notebook computer battery-pack (IBA2+(TM), Hewlett Packard) was evaluated during operation at 42 degreesC using a combination of thermal analysis and modeling. The battery-pack was charged at 2.36 A and provided 55-W constant power during discharge. Results showed the battery-pack has reasonable heat dissipation capability except that the temperature rise of its charge control IC increases to 67 degreesC, which is near the critical thermal limit of the device (73-75 degreesC). Autopsy results showed this IC has a small die to die-pad size ratio and also large volume of mold compound causing the device self-heating during the charge control process. Thermal modeling provided a detailed understanding of the thermal response of the battery under various operating conditions that helped to reduce the product design cycle-time. The overall results indicated that the battery temperature rise during charge is dominated by the power dissipation from the control electronics and during discharge by the heat dissipation from Li-ion cells. (C) 2003 Elsevier Science B.V. All rights reserved.