Research and analysis: Domestic battery energy storage systems

The application of batteries for domestic energy storage is not only an attractive ‘clean’ option to grid supplied electrical energy, but is on the verge of offering economic advantages to consumers, through maximising the use of renewable generation or by 3rd parties using the battery to provide grid services.

Even though few incidents with domestic battery energy storage systems (BESSs) are known in the public domain, the use of large batteries in the domestic environment represents a safety hazard. This report undertakes a review of the technology and its application, in order to understand what further measures might be required to mitigate the risks. The focus is on lithium-ion battery technology, as this now dominates new designs of BESS.

The study starts with a description of the operation of BESS systems, the market, and a review of the published data on battery fires. It then considers in detail how lithium-ion batteries can fail, and the mitigating measures such as best practice in BESS design and installation that can reduce the risk or impact of failure. Appendix 2 gives a comprehensive review of current safety standards and codes relating to domestic BESSs.

Fortunately, there have been few recorded fires involving domestic lithium-ion battery storage systems so this report includes experience of Li-ion battery fires in other applications. The causes and effects of thermal runaway, rapid pressure build-up and toxicity of gases are also considered.

The desk research was supplemented by 1:1 interviews and a discussion meeting with sector experts.