In a large battery pack of lithium-based cells for an electric vehicle or grid storage system, how are failed cells handled? Answers to another question indicate these cells are usually hardwired in parallel blocks (which are then connected in series and balanced) so that resistance isn't added in the path of high current.
What happens when a cell fails and acts as a short circuit?
It seems this would short out a block of parallel cells and decrease the capacity of the overall pack significantly. If the dead cell could be removed from the pack by an electronic or safety system (power transistor, fuse, physical removal &/or replacement) the rest of the parallel cells could continue functioning with a much smaller decrease in usable pack capacity.
Lead-acid batteries seem to be replaced on a timed maintenance schedule, or when certain usage metrics are exceeded, say in data center usage. With lithium batteries being so much more expensive, are there any typical electronic design features which handle failed cells automatically rather than by rotating out the entire pack before end of life?
Are chemistries such as LiFePO4, with 2000+ cycles to 80% capacity, reliable enough that cells failed to short circuit are rare enough to ignore as an electronic design issue?