Connective structure between a battery cell and a connecting bar of a battery pack
A battery pack having an improved a coupling force between a battery cell and a connecting bar of a connecting structure. The connecting structure includes at least one battery cell, a connecting bar electrically connected to the battery cell, a welding region formed at a connecting area of the battery cell and the connecting bar, and an anisotropic conductive film formed at the outer periphery of the welding region and connecting the battery cell and the connecting bar to each other.
1. A battery pack comprising:
at least one battery cell;
a connecting bar electrically and adhesively connected to the battery cell; and an anisotropic conductive film disposed between the battery cell and the connecting bar, the anisotropic conductive film having a first surface directly attached to the battery cell and an opposing second surface directly attached to the connecting bar;
an electric bonding region electrically connecting the battery cell and the connecting bar using welding, wherein the connecting bar includes a planar portion formed at a location corresponding to the electric bonding region, and a sloped portion upwardly bent around the planar portion, the anisotropic conductive film having conductivity only in a direction corresponding to a thickness direction of the anisotropic conductive film in the electric bonding region.
2. The battery pack of claim 1 , the anisotropic conductive film comprising:
an outer periphery region, formed at an outer periphery of the electric bonding region and connecting the battery cell and the connecting bar to each other.
3. The battery pack of claim 2 , further comprising a welding reinforcement member formed at an outer periphery of the anisotropic conductive film, the welding reinforcement member connecting the battery cell and the connecting bar to each other.
4. The battery pack of claim 3 , wherein the welding reinforcement member is an insulating adhesive.
5. The battery pack of claim 3 , wherein the welding reinforcement member is a double-sided adhesive tape.
6. The battery pack of claim 2 , wherein an area of the outer periphery region is larger than that of the electric bonding region.
7. The battery pack of claim 2 , wherein the outer periphery region electrically connects the battery cell and the connecting bar to each other.
8. The battery pack of claim 2 , wherein the electric bonding region is elliptically shaped.
9. The battery pack of claim 2 , wherein the electric bonding region is made of nickel (Ni) of the connecting bar, steel of the battery cell, and gold (Au) and nickel (Ni) of the anisotropic conductive film, mixed altogether.
10. The battery pack of claim 2 , wherein the electric bonding region includes a nugget region that is a trace of current flow based on a welding region; and a corona bond region formed outside the nugget region by melting and curing of the nugget region.
11. The battery pack of claim 2 , wherein the connecting bar includes a second planar portion horizontally bent about the sloping portion.
12. The battery pack of claim 1 , wherein the connecting bar is flatly formed.
13. The battery pack of claim 2 , an electrical conductivity of the electric bonding region is higher than that of the outer periphery region of the anisotropic conductive film.
14. The battery pack of claim 13 , wherein the anisotropic conductive film includes:
an adhesive; and
a plurality of conductive balls distributed in the adhesive, the conductive balls comprising a first polymer, a nickel layer surrounding the first polymer, a gold layer surrounding the nickel layer, and a second polymer surrounding the gold layer.