I'm not saying that all the safety tips and storage methods mentioned in this thread or the many others like it are wrong or bad, they're good ideas and safety measures. But storage is the least likely time for you to see an issue or a fire. Assuming you don't live in AZ and store them in the trunk of your car in July.

Simply watch your packs. Are they starting to puff, and what type of puffing?? If you have a pack that puffs abruptly for seemingly no reason while charging or running. Stop using it, there's something wrong with it. If you start to see slight puffing while running that may or may not go back down, monitor the IR and WATCH it while charging and be aware that it MAY "explode" or catch fire while running or charging in the future. Or simply stop using it and replace it. If when you're done running your vehicle and the lipo is at a safe storage voltage with no visible puffing. It's not likely to puff while sitting in storage.

IMO, while properly stored is the LEAST likely time to have a lipo failure.