Electrical cell module, and a method of assembling an electrical cell module

An electrical cell module comprising:

• an opposing pair of module end plates spaced apart from one another along a longitudinal axis;
• a first cell stack;
• and
• a second cell stack;
• wherein each of the first cell stack and second cell stack comprises:
• a series of cells stacked along the longitudinal axis, and
• a pair of stack end plates, arranged at opposing ends of the series of cells, and configured to be fixed to one another in an assembled position wherein, in the assembled position, the pair of stack end plates apply to the series of cells a compressive force along the longitudinal axis, and define a stack length of the respective cell stack;
• wherein the compressive force applied to the first cell stack and the compressive force applied to the second cell stack are each within a predetermined operable range;
• and
• wherein the electrical cell module is configured so that, in a use position, each of the opposing pair of module end plates is fixedly engaged with one corresponding stack end plate of each of the first cell stack and the second cell stack such that:
• the module end plates are spaced apart from one another along the longitudinal axis by a predetermined distance, and
• the first stack length is different to the second stack length.