. The HPE Smart storage battery is a lithium-ion low-halogen centralized backup source & is required to backup the write cache content onto flash memory on the HPE Smart Array Gen 10 & Gen 9 performance RAID (P-class) controllers in case of an unplanned server power loss. The battery is also the backup power source for HPE NVDIMMS & allows any data in flight on the DRAM to be moved to the non-volatile NAND flash. Only one battery is required per server as it can support multiple devices..