What is true regarding the mechanicak configuration of the tractive system energy storage?

1. Holes in the container are only allowed if they are necessary for the venting of explosive gas
2. Vertical walls must be made from steel 0.9 mm thick or aluminium 2.3 mm thick only
3. The mounting of the accumulator cells to the container must withstand 40 g acceleration in vertical direction
4. Fasteners to attach pouch cells to the container must comply with rule T10Correct