Secondary battery module

A secondary battery module comprising:

• a cell stack comprising a plurality of battery cells linearly arranged with respect to each other;
• a module main body comprising a variable housing accommodating the battery cells, the variable housing having an adjustable length in an arrangement direction of the battery cells and accommodating the battery cells such that the battery cells are in close contact with each other;
• a state of charge (SOC) detector configured to detect an SOC during charging and discharging of the battery cells;
• a controller configured to identify predicted expansion and contraction lengths of the cell stack according to the charging and discharging of the battery cells based on the SOC and to output a control signal;
• and
• a housing length adjuster configured to adjust the length of the variable housing based on the control signal.

A secondary battery module comprising:

• a cell stack comprising a plurality of battery cells linearly arranged with respect to each other;
• a module main body comprising a variable housing accommodating the battery cells, the variable housing configured to have an adjustable length in an arrangement direction of the battery cells and accommodates the battery cells such that the battery cells are in close contact with each other;
• a displacement sensing unit configured to detect a change in length of the cell stack;
• a controller configured to receive information about the change in length of the cell stack from the displacement sensing unit and to output a control signal based on the information about the change in length;
• and
• a housing length adjuster configured to receive the control signal and to adjust the length of the variable housing based on the control signal.