This is one of a set of 10 pictures apparently from March 2010.
The picture before this one in the set is a very nice closeup of one module from the battery pack. The + and - connections have wires attached, and the more-centered port, probably for monitoring the enclosed cells, is unused in this picture. Note how the module is designed to "nest" closely together as the modules are stacked.
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2018 & 2019 Tesla Model 3
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