SECONDARY BATTERY, SECONDARY BATTERY MODULE HAVING BUILT-IN SECONDARY BATTERY, AND ASSEMBLED BATTERY SYSTEM HAVING BUILT-IN SECONDARY BATTERY MODULE

摘要

Thermal conduction in the stacking direction of battery cells is small compared with thermal conduction in the electrode plane direction of the battery cells, which is orthogonal to the stacking direction, resulting in a non-uniform temperature distribution in the stacking direction of the battery cells. The non-uniform temperature distribution inside the stacked battery cells degrades the charging and discharging performance of the battery cells because a battery cell portion exposed to a high temperature and another battery cell portion exposed to a low temperature have different degrees of degradation associated with the charging or discharging of the battery cells.A heat absorbing means equipped with a heat absorbing function is disposed on a plane in the direction orthogonal to the stacking direction toward which the battery cells are stacked (in other words, on a plane parallel with the stacking direction), and the battery cells and the heat absorbing means are thermally connected with each other. Since the heat absorbing means and each of the battery cells are thermally connected with each other under the substantially same condition, heat generated at each of the battery cells is absorbed by the heat absorbing means at an approximately same rate, so that it is possible to prevent the temperature distribution of each of the battery cells from becoming non-uniform.