Trying to take this battery apart from Ezee Sprint electric bicycle. Have taken all the screws that are circled in the picture (all the ones that are visible). The 2 halves crack slightly open but they won’t come apart, something else is holding the 2 pieces together. Any idea what is holding the case together still after all the visible screws are taken out. It seems odd to me that there are only 3 major screws holding the case together. Shouldn’t there be another one for the other corner of the case? If so where is it? Thank you.