Structure of thin battery covered by outer packaging film, battery pack, and method for manufacturing battery pack
To provide a thinner, lighter battery pack and to reduce the cost by eliminating the need for a battery case. A thin battery pack structure using an outer packaging film (battery pack) is constructed by a flat and rectangular shaped battery cell, a flat and rectangular shaped frame portion accommodating the battery cell, a circuit board unit disposed on the outer side surface of the frame portion, a cap portion mounted on one ends of the frame portion and the battery cell so as to sandwich the circuit board unit with the outer side surface of the frame portion, and an outer packaging film for integrally covering the rectangular battery cell and the frame portion.
1. A thin battery structure comprising:
a flat battery cell approximately rectangular in shape having top and bottom surfaces and four peripheral side surfaces, and having a positive pole and a negative pole, the battery exhibiting a thickness;
a rectangular frame portion having four side surfaces accommodating the four peripheral side surfaces of said battery cell, a first side surface of the frame portion having a height substantially equal to the thickness of the battery cell at the most inflated condition of the battery cell during charging or in a high temperature, and the height of the remaining three side surfaces of the frame portion being less than the height of said first side surface, wherein a thickness of the battery cell is restricted within the height of the frame portion, thereby maintaining the thickness of the battery cell to a constant value during operation; and
an outer packaging film integrally covering said top and bottom surfaces of said battery cell and two of the side surfaces of said frame portion.
2. The thin battery structure according to claim 1 , further comprising a cap portion mounted on one end of said frame portion and said battery cell.
3. The thin battery structure according to claim 2 , further comprising a circuit board unit disposed on said one end of said frame portion and said battery cell.
4. The thin battery structure according to claim 3 , wherein said circuit board unit is disposed on an outer side surface of said frame portion, and is sandwiched between said cap portion and said outer surface of said frame portion.