A battery pack which can increase of the volumetric efficiency of the battery pack without being contained in a resin mold case is provided. A first laminate material has a concave portion formed by drawing where a battery element is contained. A second laminate material is stacked so as to cover the opening of the concave portion to seal up the periphery of the opening. The first and second laminate materials are bend inwards so as to cover the battery element, and bonded and fixed together by heating. The first laminate material has three-layer structure including a polypropylene layer, a soft aluminum layer, and a nylon layer or PET layer. The second laminate material has a similar structure but includes a hard aluminum layer. Therefore, the second laminate material has enough strength to resist deformation without being contained a cell in a resin mold case.
1. A battery pack comprising a battery element of polymer battery, wherein
the battery element is contained in a concave portion formed in a soft laminate material and is covered with a hard outer covering material such that the battery element is placed on the hard outer covering material in an opened state, and the hard outer covering material is closed where both ends of the hard outer covering material are bonded together, each of the soft laminate material and the hard outer covering material is a multi-layer film structure; and
the battery pack is shaped so as to have a substantially semicircular form in cross-section in which both sidewalls expand outwards, wherein the battery pack further includes a top cover and a rear cover made of a resin that are inserted into a respective side of an edge face of the battery element wherein the soft laminate material includes a soft metal layer composed of annealed aluminum at a thickness ranging from about 30 μm to about 130 μm, and wherein the hard outer covering material includes a hard metal layer composed of unannealed aluminum at a thickness ranging from about 30 μm to about 130 μm.
2. A battery pack comprising a battery element of polymer battery, wherein
an outer covering material of the battery back comprises first and second laminate materials having substantially the same size, each of the first and second laminate materials is a multi-layer film structure;
the battery element is contained in a concave portion formed in the first laminate material including a soft laminate material;
the first and second laminate materials are stacked on one another so that the second laminate material covers an opening of the concave portion to seal a periphery of the opening;
both ends of each of the first and second laminate materials are bonded together outside of a bottom of the concave portion of the first laminate material; the concave portion of the first laminate material for containing the battery element is formed at a position slightly shifted from the center; the second laminate material is stacked on the first laminate material so that it is slightly shifted; and
the battery pack is shaped so as to have a substantially semicircular form in cross-section in which the both sidewalls expand outwards, wherein the battery pack further includes a top cover and a rear cover made of a resin that are inserted into a respective side of an edge face of the battery element wherein the first laminate material includes a soft metal layer composed of annealed aluminum at a thickness ranging from about 30 μm to about 130 μm, and wherein the second laminate material includes a hard metal layer composed of unannealed aluminum at a thickness ranging from about 30 μm to about 130 μm.
3. The battery pack according to claim 2 , wherein positions of the first and second laminate materials are shifted.
4. The battery pack according to claim 2 , wherein the bonding layer is a heat adhesion layer, and the respective surface protective layers of the first laminate material are bonded via a heat bonding sheet on an outer surface at the bottom of the concave portion.
5. The battery pack according to claim 2 , wherein:
the first laminate material comprises a bonding layer, the soft metal layer and a surface protective layer, which are stacked on one another;
the second laminate material comprises a bonding layer, the hard metal layer and a surface protective layer, which are stacked on one another; and
the respective bonding layers of the first and second laminate materials are stacked so as to oppose each other.