Cell
A cell is provided. The cell includes a cell element including a positive electrode, a negative electrode, an electrolyte and a laminate film including an exterior layer, a metal layer, an interior layer, and a welded layer formed of the interior layer; wherein a thickness of the welded layer is larger than 5 μm in a flat portion of the interior layer, wherein the welded layer increases in thickness from the flat portion to an end portion of the welded layer, and wherein when a thickness of the laminate film is t, a thickness of the interior layer is p and a thickness of the laminate film in the welded layer is t1, a following equation is satisfied: t×2−p×2+5<t1<t×2−5 (μm).
1. A cell comprising:
a cell element including a positive electrode, a negative electrode, an electrolyte and a laminate film including an exterior layer, a metal layer, an interior layer, and a welded layer formed of the interior layer;
wherein a thickness of the welded layer is larger than 5 μm in a flat portion of the interior layer,
wherein the welded layer increases in thickness from the flat portion to an end portion of the welded layer, and
wherein when a thickness of the laminate film is t, a thickness of the interior layer is p and a thickness of the laminate film in the welded layer is t1, a following equation is satisfied:
t× 2− p× 2+5< t 1< t× 2−5 (μm).
2. The cell according to claim 1 , wherein the thickness of the welded layer in the flat portion is thinner than a thickness of the laminate film in an edge portion.
3. The cell according to claim 1 , wherein the interior layer further includes at least one layer.
4. The cell according to claim 1 , wherein the exterior layer includes one or both of a nylon and a poly(ethylene terephthalate), wherein the metal layer includes aluminum, and wherein the interior layer includes one or both of a polyolefin and a polypropylene.
5. The cell according to claim 1 , wherein the laminate film includes a first adhesive layer between the exterior layer and the metal layer and a second adhesive layer between the metal layer and the interior layer.
6. The cell according to claim 1 , wherein the positive electrode, the negative electrode and the separator are configured in a wound arrangement.
7. The cell according to claim 1 , wherein the cell includes an electrode terminal and a sealant, and wherein at least a portion of the sealant is provided on the electrode terminal.
8. The cell according to claim 1 , wherein a thickness of at least one side of the interior layer in an edge portion is from 20 μm to 40 μm.
9. A method of forming a cell including a cell element, comprising:
providing a laminate film to enclose the cell element, wherein the laminate film includes an exterior layer, an interior layer, and a metal layer,
welding the laminate film to form a welded layer of the interior layer, while not welding the laminate film in an edge portion,
wherein a thickness of the welded layer is larger than 5 μm in a flat portion of the welded layer,
wherein the welded layer increases in thickness from the flat portion to an end portion of the welded layer, and
wherein when a thickness of the laminate film is t, a thickness of the interior layer is p and a thickness of the laminate film in the welded layer is t1, a following equation is satisfied:
t× 2− p× 2+5< t 1< t× 2−5 (μm).
10. The method according to claim 9 , wherein the laminate film is welded using an ultrasonic welding.
11. The method according to claim 9 , wherein the laminate film is welded using a heat and compression welding.
12. The method according to claim 9 , wherein the cell includes a positive electrode, a negative electrode and a separator.
13. The method according to claim 12 , wherein the positive electrode, the negative electrode and the separator are wound.
14. The method according to claim 9 , wherein the cell includes an electrode terminal and a sealant, and wherein at least a portion of the sealant is provided on the electrode terminal.
15. The method according to claim 9 , wherein the thickness of the welded layer in the flat portion is thinner than a thickness of the laminate film in an edge portion.
16. The method according to claim 9 , wherein the interior layer includes at least one layer.
17. The method according to claim 9 , wherein the exterior layer includes one or both of a nylon and a poly(ethylene terephthalate), wherein the metal layer includes aluminum, and wherein the interior layer includes one or both of a polyolefin and a polypropylene.
18. The method according to claim 9 , wherein the laminate film includes a first adhesive layer between the exterior layer and the metal layer and a second adhesive layer between the metal layer and the interior layer.
19. The method according to claim 9 , wherein a thickness of at least one side of the interior layer in the edge portion is from 20 μm to 40 μm.