My 2DS' battery is bloated and I also have a broken DSi, I have cracked the 2DS' battery slot to fit the DSi battery there as the DSi battery is a bit longer than the 3DS' and yes the 2DS works with a DSi battery installed but the problem is that 2DS won't accept charge with it. If anyone knows a way to bypass this and charge the DSi battery please tell me, I'd be appreciated.