Thermal management of telecommunications batteries using phase change materials (PCM) JacketTM

Telephone operating companies have a long history of powering equipment with batteries. The life of a battery is directly related to the load applied, proper recharging and most of all, the temperature of the battery, which must be kept at optimum conditions. Batteries for back up service are normally stored in compartments attached to or inside outdoor cabinets. These compartments are exposed to solar loads and must be kept at optimum temperatures, 77°F (25°C), as prescribed by the manufacturers. Furthermore, these compartments must allow for the proper venting of hydrogen fumes that may be given off by the batteries in the course of their operating life. The use of phase change materials (PCMs) can lead to more constant operating temperature for the batteries. The PCM allows peak or cyclic (day time) heat loads to be absorbed and then rejected at a later time (night time) when ambient conditions allow their rejection. Some of the issues associated with the use of PCMs for battery compartments are also discussed in this paper. This paper describes the development, testing and evaluation of a PCM Battery Jacket^TM. The PCM jacket allows for the reduction of maintenance related to thermal malfunction and the extension of battery life by maintaining the battery temperature close to or at optimum levels. Results presented include analytical/numerical calculations of the PCM Jacket^TM´s thermal performance as well as experimental results obtained from in-house and field testing. Overall results indicate that the jacket is very effective in maintaining optimal thermal conditions