Abstract: A battery pack includes a housing, a positive terminal and a negative terminal, and a plurality of cell module assemblies. The positive terminal and negative terminal are each externally accessible from the housing and extend into a first compartment of the housing. The cell module assemblies are received in a second compartment of the housing, and are coupled to the positive terminal and the negative terminal through a connection extending from the second compartment into the first compartment. The first compartment is accessible through a first panel that is movably coupled to the housing through a first securing mechanism providing a first level of access. The second compartment is accessible through a second panel that is movably coupled to the housing through a second securing mechanism providing a second level of access.