BATTERY PACK

To provide a battery pack in which an increase in stress generated at a joint between tabs when current flows can be suppressed.SOLUTION: A battery pack 1 includes a plurality of battery cells 2 each of which includes a plate-shaped positive electrode tab 10 and a plate-shaped negative electrode tab 20 projecting from a cell body. The positive electrode tab 10 and the negative electrode tab 20 comprise metal materials having coefficients of thermal expansion different from each other, and, in the state where a plurality of the battery cells 2 are stacked, a tab on one electrode side of each battery cell 2 is joined to a tab on the other electrode side of adjacent battery cell and electrically connected thereto. In a tab made of a metal material at least having a relatively larger coefficients of thermal expansion of the positive electrode tab 10 and the negative electrode tab 20, a slit is formed such that a joint, where the positive electrode tab 10 and the negative electrode tab 20 are joined, is divided in a plate width direction.SELECTED DRAWING: Figure 1 【課題】通電時にタブ同士の接合部に生じる応力が大きくなることを抑制する組電池の提供。【解決手段】セル本体から突出する板状の正極タブ１０および負極タブ２０を有する電池セル２を複数備え、正極タブ１０と負極タブ２０とが互いに熱膨張係数の異なる金属材料からなり、複数の電池セル２が積層された状態で、電池セル２の一方の極側のタブが、隣り合う電池セルの他方の極側のタブに接合され、電気的に接続されている組電池１であって、正極タブ１０と負極タブ２０とのうち少なくとも熱膨張係数が相対的に大きい金属材料からなるタブには、正極タブ１０と負極タブ２０とが接合された接合部を板幅方向に分断するようにスリットが形成されている。【選択図】図１