Battery life time of coin cell operated wireless sensor networks

Coin cell batteries are attractive option for use in wireless sensor networks due to their small size and low cost. However, the rated capacity of the coin cells is far less than other battery form factors such as AA. Consequently the application of coin cells in wireless scenarios has been rather rare. Limited measurements have been conducted in the past, but to the best of our knowledge no capacity models exist. To access their performance in wireless environment, capacity modeling is required. Here, we develop a model for lithium CR2032 coin cell battery capacity. Results indicate that the rated capacity of a coin cell battery is not achievable. In fact, the achievable life time could be significantly short due to large current draws. To improve the performance, parallel battery configuration is proposed. It is shown that parallel coin cell battery configuration leads to significantly longer battery life compared to the single battery case. The number of batteries in the parallel configurations influences the results and performance saturation occurs when the number of parallel batteries exceeds three. Based on our estimates, battery improvement factors of up to 600% can be obtained.