According to the relevant norms and standards (or rather the science/research behind them), everything below 60VDC is safe to touch for an adult. Hence there is no requirement to prevent accidental contact (touching).
Therefore, protective clothing as for peace of mind, not necessity. Grounded or not doesn't matter, though I agree that the battery will (most likely) not be grounded.

On the other hand, tools are a lot more conductive and present different hazards like e.g. shorting the battery with high current that may melt a metal spanner. That's why I recommended the rubber cloth.

What I forgot is that you have to take off everything potentially conductive from your hands, like rings and wristwatches. Same thing as with the metal spanner, red-hot metal on bare skin is no bueno.