A Report on the Development of a Rechargeable Lithium Cell for Application in Autofocus Cameras

Abstract

This paper presents a report on the development of a rechargeable lithium cell for use specifically in autofocus cam-eras. The requirements for this cell are: a wide operating range in temperature of -40-55~ no arsenic compounds, and of course sufficient operating capacity. Data collected from simulated camera discharge tests are provided which show that these requirements were satisfied. Commercially available rechargeable lithium cells em-ploying molybdenum disulfide cathodes are manufac-tured by Molt Energy, Limited, under the trade name Mo-licel TM. One of the OEM applications the cells were targeted for was the autofocus camera. For this application an operating temperature range of -40-55~ was required and in addition the cell was to be arsenic free. The low-temperature operating requirement and the electrolyte salt restriction necessitated the development of a suitable electrolyte. The electrolyte employed was 0.75M LiPF6 in a 75/25 (v/v) mixture of 2-methyltetrahydrofuran (2-MeTHF) and ethylene carbonate (EC). This electrolyte is similar to that studied by Yoshimatsu et al. (1) where LiAsF0 was used as the electrolyte salt. This paper reports on the de-velopment of our autofocus camera cell, designated as X-75.