Energetica India Magazine: september 2020

ENERGY STORAGE Advances in Battery Safety and Technology Energy storage safety; lessons learned in practical application 30 energetica INDIA- September_2020 Advances in Battery Safety and Tech- nology Battery technology has evolved very quickly, but the lithium-ion energy stor- age industry is still relatively young. As of today, there are few commercial sys- tems that can claim to have been in op- eration for more than 10 years. Despite this, the economic and environmental advantages of battery storage have meant that there are now hundreds of systems operating around the world. In 2009, I was a part of the group that produced the first lithium batteries for industrial applications. These were de- signed to demonstrate the principal that Megawatt scale Energy Storage Sys- tems (ESS) could deliver real commer- cial value; at the time, there were a lot of doubters. Today, we have evolved not only performance, but also safety, inte- gration, cost and risk management to much more predictable levels. The data obtained from constant commercial use continues to provide valuable informa- tion that allows us to continuously im- prove our systems. This data and experience have led to significant improvements in battery de - sign resulting in improved safety, sys- tem life, risk reduction and overall per- formance. The improved performance Brent Perry CEO, Sterling PBES Figure1: CanPower TM Microgrid in a Box. 2MWh battery located inside a 20-foot ISO shipping container. Image Courtesy Sterling PBES. of modern industrial batteries has also changed the market. Lower system cost means more and more renewable ener- gy installations are now finding true ROI from energy storage. Safety One critical weakness from the lithi- um-ion battery industry is fire safety, with the main concern being how to provide a cost-effective system while maintain- ing operational safety. This challenge was at the top of our minds in every de- sign decision, and we addressed with our patented CellCool TM cooling system. A cooling system so effective, it removes the risk of thermal runaway. The principal is very simple; reduce the temperature of the cells at a faster rate than the cell increases in temperature. No matter how hard you work them, with CellCool a Sterling PBES battery will not achieve the temperature required to go into thermal runaway. We worked in cooperation with regulators to develop safety tests designed to demonstrate that the batteries are inherently safe. Even in these very demanding tests, we have proven success. Our CellCool sys- tem is able to prevent thermal runaway, making every system safer to operate. This is done with an inherently simple liquid cooling system and cannot be achieved with air cooling systems due to the inefficiency of heat to air transfer. Safety has other considerations as well. We designed a Battery Manage- ment System (BMS) that is inherently focussed on protecting the facility, the battery system and the cells. This is done at its core by monitoring the volt- age and temperature of every individual cell in the system, and then balancing the performance within safe operating parameters. Another critical element of safety in de- sign has been the inclusion of contac- tors in the individual battery modules. We are building DC voltage systems that range from 300-1500 VDC, therefore the risk of personal injury in transportation, installation and service have high poten- tial. For example, a 1500 VDC arc flash can permanently disable a technician. By adding contactors in the individual