The present invention relates to a case system for lead batteries. The case system comprises of a one piece, essentially box shaped cell-housing part with at least 4 sidewalls enclosing an interior volume. At least one division plane divides said interior volume, such as to form a plurality of compartments. Each of the compartments is adapted for storing an electrical cell. The case system further comprises an access wall part with electrical conductor openings or terminal feed throughs and at least one fluid channel opening. Furthermore the case system comprises a closure wail part for sealing off said casing system. Each of the at least one division planes is essentially perpendicular to the same two opposite side walls of the essentially box shaped cell housing. The present invention further relates to a lead battery and a battery rack incorporating the above described advantageous case system.