Battery module comprising a heat transfer component and a thermal expansion material between cells

A battery module comprising:

• a plurality of battery cells arranged side by side in a first direction and including a first battery cell and a second battery cell adjacent to the first battery cell;
• and
• a first heat transfer component and a first thermal expansion material member that are disposed between at least the first battery cell and the second battery cell,
• wherein the first thermal expansion material member has a thermal conductivity lower than a thermal conductivity of the first heat transfer component and expands at a first predetermined temperature or higher,
• wherein when temperature of the first thermal expansion material member is less than the first predetermined temperature, the first and second battery cells are connected to each other via a high thermal conductive route including the first heat transfer component that touches at least one of the first and second battery cells and having a first thermal conductivity, and
• wherein when the temperature of the first thermal expansion material member reaches the first predetermined temperature or higher, the first and second battery cells are connected to each other via a low thermal conductive route that has a second thermal conductivity lower than the first thermal conductivity and is constituted by the first thermal expansion material member, by cutting off the high thermal conductive route between the first and second battery cells by expansion of the first thermal expansion material member, wherein the low thermal conductive route does not include a route without the first thermal expansion material member.