An Evaluation of Different Thermal Control Techniques for Valve Regulated Lead Acid (VRLA) Battery
International Journal of Advanced Research in Science, Engineering and Technology
The VRLA battery is one of the most temperature sensitive battery. Slightly change in operating temperature is largely affect the performance and lifespan of VRLA battery. So, thermal control of VRLA batteries are most important for improving the battery life and performance. There are mainly two objectives of the thermal control strategy (1) to control the exchange of heat between each adjacent battery in battery pack and(2) to isolate the battery pack from environment. Always develop a
... control strategy in such a way that the environmental condition inside battery packs remains within the optimum operational temperature range. There are mainly three types of thermal control techniques (a) A passive thermal control system which maintains the battery pack temperature within the optimum operating temperature range through thermo physical and geometrical considerations only. (b) A semi passive thermal control system involves the transfer of heat from hot to cold sink. (c) A active thermal control system involves the transfer of heat from cold to hot sink. In this paper, all of above thermal control techniques described in detail and evaluated the best thermal control method for VRLA batteries. Also summaries the different types of advance thermal control systems for VRLA battery.. KEYWORDS: VRLA Battery, Phase Change Material (PCM), Thermal energy storage system, heat transfer, optimum temperature range. I. INTRODUCTION Proper thermal control of the battery pack is most important for improve the performance and lifespan of the VRLA battery. Proper controlling of the temperature inside the battery pack is reducing the risk of thermal runaway. So due to that reason thermal control strategy of battery pack should be equipped with for essential functions to ensure the right operating condition. 1. Cooling: During charging and discharging process heat is continue generated from the batteries. So temperature inside the battery pack is gradually increasing which responsible for reducing the life of the battery. Thus cooling function must be required in thermal control system for maintain the temperature around the batteries inside battery pack. 2. Heating: In cold climate, battery pack temperature fall down below the lower limit operating temperature range. This increases the internal resistance inside the battery. So heating function should be required. 3. Insulation: In extreme cold or hot climate, temperature of the battery pack is continuously varying. So, battery temperature rise and fall continuously out of the optimum operating temperature range. So prevent the batteries from variable climatic condition, proper insulation should be required. 4. Ventilation: Ventilation should be required to remove the hazardous gasses which generates during the charging-discharging process within battery pack. The thermal control system for battery should be equipped with those components which able to fulfil the following functions. Here, outline the thermal control techniques which able to fulfil the required functions.