If batteries are to be subjected to vibration in use then internal damage can be prevented by by filling the air spaces inside the battery with a rigid foam to make the battery a solid unit. The foam can be a single part or 2 part foam which is injected into the battery. The foam then expands to fill all the spaces within the battery and cures to solid over a period of 24 hours to render the finished battery solid and resistant to vibration. The use of foam has minimal effect on the weight of the battery. This technique is used for batteries used in the rail industry.