Pouch Cell

Abstract

To improve the strength around a junction between a current collecting tab and a lead, improves the airtightness of a pouch cell, prevent a decrease in energy density, and reduce the number of components.SOLUTION: A pouch cell 10 that includes: a substantially rectangular parallelepiped storage / discharge element 11; current collecting tab leads 12 that are thinner than the storage / discharge element and are drawn out from the storage / discharge element; and an exterior film 13 that wraps the storage / discharge element in a state in which the current collecting tab leads are drawn out. The exterior film includes: sandwiching portions 14 in which the exterior film sandwiches the current collecting tab leads from front and back surfaces in a thickness direction; folded portions 15 extending along a contour of the sandwiching portion; and reinforcing portions 16 that are folded back from the folded portions and joined to at least the sandwiching portions. The folded portions include extension portions 17 in which the folded portion are joined to the side portions extending in the thickness direction of the holding portion, the reinforcing portion is folded back in the direction in which the current collecting tab lead is sandwiched by the folded portions, and the reinforcing portion extends from the folded portion along the direction in which the current collecting tab lead is drawn out or in a crossing direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to pouch cells, such as batteries. [Background technology]

[0002] In recent years, the demand for high-capacity, high-power batteries has been rapidly expanding due to the widespread use of various large and small electric and electronic devices such as automobiles, personal computers, and mobile phones. Examples of such batteries include liquid battery cells that use an organic electrolyte between the positive and negative electrodes, and solid battery cells that use a flame-retardant solid electrolyte instead of an organic electrolyte.

[0003] A known solid-state battery is a laminated cell type pouch cell, in which a rectangular parallelepiped cell is wrapped in a laminate film and sealed into a plate shape. By wrapping the cell in an exterior body (film), moisture and air are prevented from entering the battery.

[0004] For example, Patent Document 1 discloses a pouch cell in which such a film is wrapped around a battery body for packaging. This discloses that an extended end 7 is provided on the periphery of a laminate (lithium ion battery packaging material) 10 constituting an exterior film (exterior body) P, and that the extended end 7 is folded back and thermally bonded to cover a cross section F1 with the extended end 7, thereby preventing the infiltration of moisture from this cross section F1. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2003-242942 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in a pouch cell, the joint between the current collecting tab and the lead is protected only by the exterior film in the triangular prism-shaped portion that contains the current collecting tab and the lead, and therefore it is desired to increase the strength of this portion. Furthermore, the above-mentioned patent documents do not disclose any improvement in strength around the current collecting tabs and leads, and there is room for improvement in this respect.

[0007] In addition, there is a gap in the part of the exterior film that clamps the current collecting tab and the lead (the lead clamping part), which can allow water or air to get in, and in order to prevent this, a long sealing part is often formed. However, this type of structure can cause problems such as a decrease in the energy density of the battery cell.

[0008] The present invention has been made in consideration of the above circumstances, and aims to achieve the following objects. 1. To improve the strength of the periphery of the joint between the current collecting tab and the lead. 2. To improve the airtightness of pouch cells. 3. Preventing a decrease in energy density and suppressing an increase in the number of component parts. [Means for solving the problem]

[0009] As a means for solving the above problem, the invention described in claim 1 comprises a substantially rectangular parallelepiped storage / discharge element (11), a current collecting tab lead (12) that is thinner than the storage / discharge element (11) and is drawn out from the storage / discharge element (11), and an exterior film (13) that packages the storage / discharge element (11) in a state in which the current collecting tab lead (12) is drawn out to the outside; A pouch cell (10) comprising: the exterior film (13) has a clamping portion (14) that clamps the current collecting tab lead (12) from the front and back sides in the thickness direction, a folded-back portion (15) that follows the contour of the clamping portion (14), and a reinforcing portion (16) that is folded back from the folded-back portion (15) and joined to at least the clamping portion (14), The folded portion (15) is joined to a side portion extending in the thickness direction of the clamping portion (14), The reinforcing portion (16) is folded back by the folded back portion (15) in a direction in which the current collecting tab lead (12) is sandwiched therebetween, The reinforcing portion (16) has an extension portion (17) extending from the folded-back portion (15) along a direction in which the current collecting tab lead (12) is pulled out or along a direction intersecting the direction. The present invention provides a pouch cell characterized by the above. The invention described in claim 2 is the pouch cell (10) described in claim 1, wherein the reinforcing portion (16) has a second extending portion (17a1-17d1) that is attached closer to the storage / discharge element (11) than the clamping portion (14). It is characterized by: The invention described in claim 3 is the pouch cell (10) described in claim 1 or 2, wherein the reinforcing portion (16) is formed with an escape portion (18) spaced apart from the current collecting tab lead (12) near the boundary between the folded-back portion (15) and the extending portion (17) so that the current collecting tab lead (12) pulled out from the clamping portion (14) does not hinder the close contact of the reinforcing portion (16) with the clamping portion (14). It is characterized by: The invention described in claim 4 is the pouch cell (10) according to any one of claims 1 to 3, wherein the exterior film (13) has a second folded-back portion (15f, 15h) that follows the contour of the clamping portion (14), and a second reinforcing portion (16f, 16h) that is folded back from the second folded-back portion (15f, 15h) and joined to at least a surface of the clamping portion (14) opposite to the reinforcing portion (16), The second folded portion (15f, 15h) is joined to a side portion extending in a thickness direction of the clamping portion (14), the second reinforcing portion (16f, 16h) is folded back by the second folded back portion (15f, 15h) in a direction in which the current collecting tab lead (12) is sandwiched therebetween; It is characterized by: Effect of the Invention

[0010] According to the invention described in claim 1, by providing the reinforcing portion, the end of the clamping portion where the flat current collecting tab lead is drawn to the outside by laminating the exterior film can be covered by the folded portion provided parallel to the end, and further the flat surface of the clamping portion can be covered by the extending portion. As a result, the reinforcing portion is welded to the clamping portion, thereby improving the airtightness at the end of the clamping portion. At the same time, the extending portion is welded to the flat surface of the clamping portion, thereby improving the strength and rigidity of the clamping portion. Therefore, the portion where the current collecting tab lead is provided in the pouch cell can be reinforced. Moreover, since the reinforcing portion can be formed by simply folding back the exterior film, it is possible to improve the airtightness and improve the rigidity and strength without increasing the number of parts. Here, the side of the clamping portion includes the end surface where the current collecting tab lead is drawn out from the clamping portion and the side surface formed so as to extend in the thickness direction by connecting the front and back surfaces of the clamping portion by the folded back exterior film. In addition, when the folded-back portion is formed on the side of the clamping portion extending in the pull-out direction of the current collecting tab lead, the reinforcing portion is welded by wrapping around the side of the clamping portion near the area where the thickness of the front and back surfaces of the exterior film expands into a triangular prism shape from the clamping portion toward the storage and discharge element, thereby preventing the welded portion from peeling off due to external force near the triangular prism shape. According to the invention described in claim 2, the reinforcing portion has a second extension portion in the triangular prism-shaped portion formed by covering the area where the exterior film is pulled out from the storage / discharge element to the outside of the current collecting tab lead, i.e., in the portion where the clamping portion is close to the storage / discharge element, so that it is possible to cover and reinforce the exterior film on the triangular prism-shaped surface, which had room for improvement in terms of durability. Here, since the thickness of the current collecting tab lead is smaller than that of the storage / discharge element, the portion of the current collecting tab lead that is pulled out from the storage / discharge element forms a step, and the exterior film that covers this portion is triangular prism-shaped, so this portion needs to be reinforced for strength and rigidity is required. According to the invention recited in claim 3, the relief portion is formed, so that it is possible to prevent the current collecting tab lead from impeding the adhesion of the reinforcing portion to the clamping portion near the boundary between the folded-back portion and the extending portion, thereby further improving the airtightness at the end of the clamping portion where the current collecting tab lead is drawn out to the outside. According to the invention described in claim 4, the second reinforcing portion is welded to the surface of the clamping portion opposite in the thickness direction to the surface to which the reinforcing portion is welded, thereby further reinforcing the clamping portion and preventing peeling of the welded portion due to external force in the triangular prism-shaped portion where the current collecting tab lead is pulled out from the storage / discharge element. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view showing a first embodiment of a pouch cell according to the present invention. [Diagram 2] FIG. 1 is a development view showing an exterior film forming a first embodiment of a pouch cell according to the present invention. [Diagram 3] 3 is an end view showing an end face of a clamping part in the first embodiment of the pouch cell according to the present invention. FIG. [Figure 4] FIG. 2 is a process diagram showing a covering process with an exterior film in the first embodiment of the pouch cell according to the present invention. [Diagram 5] FIG. 2 is a process diagram showing a covering process with an exterior film in the first embodiment of the pouch cell according to the present invention. [Figure 6] FIG. 2 is a process diagram showing a covering process with an exterior film in the first embodiment of the pouch cell according to the present invention. [Figure 7] FIG. 4 is a perspective view showing a second embodiment of a pouch cell according to the present invention. [Figure 8] FIG. 4 is a development view showing an exterior film forming a second embodiment of the pouch cell according to the present invention. [Figure 9] FIG. 11 is a perspective view showing a third embodiment of a pouch cell according to the present invention. [Figure 10] FIG. 11 is a development view showing an exterior film forming a third embodiment of the pouch cell according to the present invention. [Figure 11] FIG. 11 is an end view showing an end face of a clamping part in a third embodiment of a pouch cell according to the present invention. [Figure 12] FIG. 11 is an enlarged development view showing the vicinity of a folded-back portion of an exterior film forming a fourth embodiment of the pouch cell according to the present invention. [Figure 13] FIG. 13 is an end view showing an end face of a clamping part in a fourth embodiment of a pouch cell according to the present invention. [Figure 14] FIG. 11 is an enlarged development view showing the vicinity of the folded-back portion of another example of an exterior film forming the pouch cell according to the fourth embodiment of the present invention. [Figure 15] FIG. 11 is an enlarged development view showing the vicinity of the folded-back portion of another example of an exterior film forming the pouch cell according to the fourth embodiment of the present invention. [Figure 16] FIG. 11 is an enlarged development view showing the vicinity of the folded-back portion of another example of an exterior film forming the pouch cell according to the fourth embodiment of the present invention. [Figure 17] FIG. 11 is a perspective view showing a fifth embodiment of a pouch cell according to the present invention. [Figure 18] FIG. 11 is a development view showing an exterior film forming a pouch cell according to a fifth embodiment of the present invention. [Figure 19] FIG. 13 is a schematic diagram showing a triangular prism-shaped portion in a pouch cell according to a fifth embodiment of the present invention. [Figure 20] FIG. 13 is an end view showing an end face of a clamping portion in another example of the fifth embodiment of the pouch cell according to the present invention. [Figure 21] FIG. 13 is a development view showing an exterior film forming a pouch cell according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] A first embodiment of a pouch cell according to the present invention will be described below with reference to the drawings. The present invention is not limited to the following embodiment, and can be modified as appropriate within the scope of the object of the present invention. Fig. 1 is a perspective view showing a pouch cell in this embodiment, Fig. 2 is a development view showing an exterior film of the pouch cell in this embodiment, and Fig. 3 is an end view showing an end of a clamping part of the pouch cell in this embodiment. In the figures, reference numeral 10 denotes a pouch cell.

[0013] A pouch cell 10 according to this embodiment includes a storage / discharge element 11, a current collecting tab lead 12, an exterior film 13, a clamping portion 14a, a folded portion 15, and a reinforcing portion 16, as shown in FIG.

[0014] The pouch cell 10 is a battery cell. This battery may be a liquid battery cell that uses an organic electrolyte as an electrolyte, a battery cell that has a gel electrolyte, or a solid battery cell that has a flame-retardant solid electrolyte as the electrolyte instead of an organic electrolyte. In the following, a solid battery cell that has a solid electrolyte will be described as an example of the battery cell.

[0015] The storage / discharge element 11 is a laminate in which a positive electrode layer and a negative electrode layer are laminated, and a solid electrolyte layer is disposed between the positive electrode layer and the negative electrode layer. In this specification, the term "laminated" means that the listed layers are laminated, and may include not only layers directly laminated, but also layers indirectly laminated. For example, there may be another layer between the positive electrode layer and the solid electrolyte layer.

[0016] The storage / discharge element 11 is covered with an exterior film 13 . The storage / discharge element 11 is a substantially rectangular parallelepiped. As shown in Fig. 1, the storage / discharge element 11 is in the form of a plate whose thickness in the Z direction is smaller than those in the X and Y directions. When viewed in the Z direction, the Y direction of the storage / discharge element 11 is the longitudinal direction and the X direction is the lateral direction. Note that the X, Y, and Z directions are shown for the sake of convenience. In the storage / discharge element 11, a plurality of current collector tabs extend from the end in the Y direction, and current collector tab leads 12 connected to the current collector tabs are further drawn out in the Y direction.

[0017] The current collecting tab lead 12 includes two current collecting tab leads 12a and 12b that are drawn out from the ends of the storage / discharge element 11 in the Y direction. The current collecting tab lead 12a is drawn out from an end of the storage / discharge element 11 on the right side in Fig. 1 in the Y direction. The current collecting tab lead 12b is drawn out from an end of the storage / discharge element 11 on the left side in Fig. 1 in the Y direction.

[0018] The current collecting tab lead 12a and the current collecting tab lead 12b are drawn out from the storage / discharge element 11 in opposite directions along the Y direction. The current collecting tab lead 12a and the current collecting tab lead 12b extend in the Y direction. The current collecting tab lead 12a and the current collecting tab lead 12b are connected to the storage / discharge element 11, and the ends opposite to the storage / discharge element 11 side are exposed from the exterior film 13. The current collecting tab lead 12a and the current collecting tab lead 12b both have a small thickness dimension in the Z direction and are formed into a flat plate shape in the XY directions. The current collecting tab lead 12a and the current collecting tab lead 12b are both connected near the center of the storage / discharge element 11 in the X direction.

[0019] The current collecting tab lead 12a and the current collecting tab lead 12b both have a thickness dimension in the Z direction smaller than the thickness dimension in the Z direction of the storage / discharge element 11. The current collecting tab lead 12a and the current collecting tab lead 12b both have a dimension in the X direction smaller than the dimension in the X direction of the storage / discharge element 11. The current collecting tab lead 12a and the current collecting tab lead 12b are both covered with an exterior film 13 at the portions adjacent to the storage / discharge element 11 in the Y direction.

[0020] As shown in Fig. 1, the exterior film 13 is wrapped around the storage / discharge element 11 in a cylindrical shape, and both ends in the Y direction are stretched outward away from the storage / discharge element 11, and the exterior film 13 holds the current collecting tab lead 12a and the current collecting tab lead 12b from the front and back sides in the Z direction. The thickness of the exterior film 13 decreases at the boundaries between the storage / discharge element 11 and the current collecting tab lead 12a and the current collecting tab lead 12b, which have different thicknesses, so that the exterior film 13 forms a triangular prism shape from the storage / discharge element 11 to the current collecting tab lead 12a and the current collecting tab lead 12b. In this triangular prism shape, the parts of the exterior film 13 that form gussets at both ends in the X direction are folded inward. The exterior film 13 seals the storage / discharge element 11.

[0021] The exterior film 13 is a sheet of pouch film as shown in Fig. 2. The exterior film 13 is wrapped around the axis in the Y direction and adhered and joined to the storage / discharge element 11. The exterior film 13 is in intimate contact with the storage / discharge element 11 except for both ends in the Y direction. The exterior film 13 is not particularly limited as long as it is a film that can house and hermetically seal the storage / discharge element 11. The exterior film 13 is preferably a film that can provide airtightness to the pouch cell 10.

[0022] The exterior film 13 may have a barrier layer made of an inorganic thin film, such as a metal foil of aluminum, nickel, stainless steel, or the like. By providing the barrier layer, the exterior film 13 can be made airtight. The exterior film 13 preferably has a seal layer made of a flexible resin, such as a polyethylene resin. The exterior film 13 can be joined by welding laminated seal layers facing each other. This eliminates the need for a step of applying an adhesive. The exterior film 13 does not necessarily have to have a seal layer. In this case, the pouch cell 10 can be formed by bonding the exterior films 13 together with an adhesive.

[0023] The exterior film 13 may be, for example, a laminate in which a base layer made of polyethylene terephthalate, polyethylene naphthalate, nylon, polypropylene, etc., the barrier layer, and the seal layer are laminated together. These layers may be laminated via a conventionally known adhesive, or may be laminated by an extrusion coating method or the like. The preferred thickness of the exterior film 13 varies depending on the material, but is preferably 50 μm or more, and more preferably 100 μm or more. The preferred thickness of the exterior film 13 is preferably 700 μm or less, and more preferably 200 μm or less.

[0024] The exterior film 13 may be a single-layer film or a film in which multiple layers are laminated. The exterior film 13 in this embodiment may be a sheet of film that accommodates and seals the storage / discharge element 11 by itself. The exterior film 13 is welded to the front and back surfaces in the Z direction of the current collecting tab leads 12a and 12b at a position outside the Y direction of the storage and discharge elements 11 and spaced apart in the Y direction from the storage and discharge elements 11. The exterior film 13 forms a clamping portion 14 outside the Y direction of the storage and discharge elements 11.

[0025] As shown in FIG. 1, the clamping portion 14 has a clamping portion 14a that clamps the current collecting tab lead 12a, and a clamping portion 14b that clamps the current collecting tab lead 12b. Both clamping portion 14a and clamping portion 14b extend in the Y direction. Clamping portion 14a and clamping portion 14b extend symmetrically in the Y direction from the center of storage / discharge element 11. The X-direction dimensions of clamping portion 14a and clamping portion 14b are approximately the same as the X-direction dimension of storage / discharge element 11. Current collecting tab lead 12a and current collecting tab lead 12b are exposed from the outer ends in the Y direction of clamping portion 14a and clamping portion 14b, respectively.

[0026] In the clamping portions 14a and 14b, the current collecting tab leads 12a and 12b are located in the center in the X direction, respectively. In the clamping portions 14a and 14b, the exterior film 13 is directly bonded to both end portions in the X direction. The clamping portion 14a and the clamping portion 14b have a substantially rectangular outline when viewed in the Z direction. A reinforcing portion 16 is welded to the Z-direction surfaces of the clamping portion 14a and the clamping portion 14b. A folded-back portion 15 is formed in the exterior film 13 on the back surface in the Z direction of the clamping portion 14a and the clamping portion 14b.

[0027] 1 and 2, the exterior film 13 is continuous so that the side closer to the storage / discharge element 11 in the Y direction than the clamping portions 14a and 14b becomes larger to the Z direction thickness dimension of the storage / discharge element 11. In response to the increase in the thickness dimension from the clamping portions 14a and 14b to the storage / discharge element 11, the exterior film 13 forms triangular prism-shaped portions 14c and 14d on the side closer to the storage / discharge element 11 in the Y direction than the clamping portions 14a and 14b.

[0028] In triangular prism portion 14c and triangular prism portion 14d, both ends in the X direction are folded inward to form gusset portions 14e to 14h, as shown in Fig. 1 and Fig. 2. Note that exterior film 13 with gusset portions 14e to 14h formed therein is extended outward in the Y direction in a direction away from storage / discharge element 11 while being folded in the Z direction, as shown in Fig. 2, and extends halfway between clamping portion 14a and clamping portion 14b. The Y direction ends of exterior film 13 with gusset portions 14e to 14h formed therein are clamped between clamping portion 14a and clamping portion 14b.

[0029] 1 to 3, the folded portion 15 has a folded portion 15a and a folded portion 15b welded to a part of the Y direction end of the clamping portion 14a. The folded portion 15 has a folded portion 15c and a folded portion 15d welded to a part of the Y direction end of the clamping portion 14b.

[0030] The folded portion 15a and the folded portion 15b are formed along the contour of the Y-direction end portion of the clamping portion 14a. The folded portion 15a and the folded portion 15b have a dimension in the Z direction that is approximately the same as the Z-direction dimension of the clamping portion 14a at the Y-direction end portion. The folded portion 15a and the folded portion 15b extend from the upper end in the Z direction to the lower end in the Z direction at the Y-direction end portion of the clamping portion 14a. The folded portion 15a and the folded portion 15b are located outward in the X direction from the current collecting tab lead 12a at the Y-direction end portion of the clamping portion 14a.

[0031] 1 to 3, the folded-back portion 15a covers the current collecting tab lead 12a to the front side in the X direction at the Y direction end of the clamping portion 14a. The folded-back portion 15b covers the current collecting tab lead 12a to the rear side in the X direction at the Y direction end of the clamping portion 14a, as shown in FIG. The folded portion 15a and the folded portion 15b have a substantially rectangular outline when viewed in the Y direction. The folded portion 15a has a contour shape and area substantially equal to those of the folded portion 15b.

[0032] The folded portion 15c and the folded portion 15d are formed along the contour of the Y-direction end portion of the clamping portion 14b. The folded portion 15c and the folded portion 15d have a dimension in the Z direction that is approximately the same as the Z-direction dimension of the clamping portion 14b at the Y-direction end portion. The folded portion 15c and the folded portion 15d extend from the upper end in the Z direction to the lower end in the Z direction at the Y-direction end portion of the clamping portion 14b. The folded portion 15c and the folded portion 15d are located outward in the X direction from the current collecting tab lead 12b at the Y-direction end portion of the clamping portion 14b.

[0033] As shown in Fig. 1, the folded-back portion 15c covers the current collecting tab lead 12b to the rear side in the X direction at the Y direction end of the clamping portion 14b. As shown in Fig. 1, the folded-back portion 15d covers the current collecting tab lead 12b to the front side in the X direction at the Y direction end of the clamping portion 14b. The folded portion 15c and the folded portion 15d have a substantially rectangular outline when viewed in the Y direction. The folded portion 15c has a contour shape and area substantially equal to those of the folded portion 15d.

[0034] As shown in Figures 1 to 3, the reinforcing portion 16 is welded to the Z-direction surfaces of the clamping portion 14a and the clamping portion 14b. The reinforcing portion 16 has reinforcing portion 16a and reinforcing portion 16b welded to the Z-direction surface of the clamping portion 14a. The reinforcing portion 16 has reinforcing portion 16c and reinforcing portion 16d welded to the Z-direction surface of the clamping portion 14b. The reinforcing portion 16 has an extending portion 17 extending along the Y direction.

[0035] 1 to 3, the reinforcing portion 16a is connected to the folded portion 15a. The reinforcing portion 16a is connected to the Z-direction surface side of the clamping portion 14a of the folded portion 15a. The reinforcing portion 16a has an extending portion 17a extending along the Y direction in which the current collecting tab lead 12a is pulled out from the folded portion 15a. In this embodiment, the contour shape of the extension portion 17a is substantially the same as the contour shape of the reinforcing portion 16a.

[0036] The reinforcing portion 16a is connected to the entire length of the folded-back portion 15a in the X direction, and further extends in the X direction to a position where it overlaps with the current collecting tab lead 12a when viewed in the Z direction. The reinforcing portion 16a has a dimension in the Y direction that is approximately the same as the dimension in the Y direction of the clamping portion 14a.

[0037] The reinforcing portion 16b is connected to the folded portion 15b. The reinforcing portion 16b is connected to the Z-direction surface side of the clamping portion 14a of the folded portion 15b. The reinforcing portion 16b has an extending portion 17b extending along the Y direction in which the current collecting tab lead 12a is pulled out from the folded portion 15b. In this embodiment, the contour shape of the extension portion 17b is substantially the same as the contour shape of the reinforcing portion 16b.

[0038] The reinforcing portion 16b is connected to the entire length of the folded-back portion 15b in the X direction, and further extends in the X direction to a position overlapping with the current collecting tab lead 12a as viewed in the Z direction. The reinforcing portion 16b has a dimension in the Y direction that is approximately the same as the dimension in the Y direction of the clamping portion 14a. The reinforcing portion 16a and the reinforcing portion 16b have substantially the same contour shape and area. The reinforcing portion 16a and the reinforcing portion 16b are close to each other near the center of the clamping portion 14a in the X direction. The reinforcing portion 16a and the reinforcing portion 16b may overlap each other near the center of the clamping portion 14a in the X direction.

[0039] The reinforcing portion 16c is connected to the folded portion 15c. The reinforcing portion 16c is connected to the Z-direction surface side of the clamping portion 14b of the folded portion 15c. The reinforcing portion 16c has an extending portion 17c that extends along the Y direction in which the current collecting tab lead 12b is pulled out from the folded portion 15c. In this embodiment, the contour shape of the extension portion 17c is substantially the same as the contour shape of the reinforcing portion 16c.

[0040] The reinforcing portion 16c is connected to the entire length of the folded-back portion 15c in the X direction, and further extends in the X direction to a position overlapping with the current collecting tab lead 12b as viewed in the Z direction. The reinforcing portion 16c has a dimension in the Y direction that is approximately the same as the dimension in the Y direction of the clamping portion 14b.

[0041] The reinforcing portion 16d is connected to the folded portion 15d. The reinforcing portion 16d is connected to the Z-direction surface side of the clamping portion 14b of the folded portion 15d. The reinforcing portion 16d has an extending portion 17d that extends along the Y direction in which the current collecting tab lead 12b is pulled out from the folded portion 15d. In this embodiment, the contour shape of the extension portion 17d is substantially the same as the contour shape of the reinforcing portion 16d.

[0042] The reinforcing portion 16d is connected to the entire length of the folded-back portion 15d in the X direction, and further extends in the X direction to a position overlapping with the current collecting tab lead 12b as viewed in the Z direction. The reinforcing portion 16d has a dimension in the Y direction substantially the same as the dimension in the Y direction of the clamping portion 14b. The reinforcing portion 16c and the reinforcing portion 16d have substantially the same contour shape and area. The reinforcing portion 16c and the reinforcing portion 16d are close to each other near the center of the clamping portion 14b in the X direction. The reinforcing portion 16c and the reinforcing portion 16d may overlap each other near the center of the clamping portion 14b in the X direction.

[0043] In the pouch cell 10 of this embodiment, reinforcing parts 16a and 16b are attached to the surface of the clamping part 14a. In addition, in the clamping part 14a formed by laminating the exterior film 13, the end part is covered by the folded part 15a and 15b. At the end part of the clamping part 14a, the reinforcing parts 16a and 16b are folded toward the surface of the clamping part 14a. At the end part of the clamping part 14a, the folded part 15a and 15b are connected to the back surface of the clamping part 14a in the Z direction.

[0044] This improves the airtightness at the end of the clamping portion 14a. At the same time, the extension portion 17a of the reinforcing portion 16a and the extension portion 17b of the reinforcing portion 16b are welded to the flat surface of the clamping portion 14a, thereby improving the strength and rigidity of the clamping portion 14a. Therefore, the portion of the pouch cell 10 where the current collecting tab lead 12a is provided can be reinforced.

[0045] Similarly, reinforcing parts 16c and 16d are attached to the surface of clamping part 14b. In addition, in clamping part 14b formed by laminating exterior film 13, its end is covered by folded parts 15c and 15d. At the end of clamping part 14b, reinforcing parts 16c and 16d are folded toward the surface of clamping part 14b. At the end of clamping part 14b, folded parts 15c and 15d are connected to the back surface of clamping part 14b in the Z direction.

[0046] This improves the airtightness at the end of the clamping portion 14b. At the same time, the extension 17c of the reinforcing portion 16c and the extension 17d of the reinforcing portion 16d are welded to the flat surface of the clamping portion 14b, thereby improving the strength and rigidity of the clamping portion 14b. Therefore, the portion of the pouch cell 10 where the current collecting tab lead 12b is provided can be reinforced.

[0047] A method for producing the pouch cell 10 will now be described.

[0048] 4 to 6 are process diagrams showing the process of covering the pouch cell with an exterior film in this embodiment. In this embodiment, the storage / discharge element 11 is placed on the exterior film 13 on which a folding line is formed, and the exterior film 13 is folded back into a cylindrical shape so as to be sealed, thereby forming a pouch cell.

[0049] 2, the exterior film 13 has a plurality of parallel folding lines FX1-FX6b along the X direction and a plurality of parallel folding lines FY1-FY4 along the Y direction. The folding lines FX1-FX4 and FY1-FY4 are all formed linearly. Also, the gusset portions 14e, 14f, 14g, and 14h have oblique folding lines that do not follow the X direction or the Y direction.

[0050] Folding line FX1 is formed at the boundary between clamping portion 14a and triangular prism portion 14c. Folding line FX2 is formed at the boundary between triangular prism portion 14c and central portion 13a that encases storage / discharge element 11. Folding line FX3 is formed at the boundary between central portion 13a that encases storage / discharge element 11 and triangular prism portion 14d. Folding line FX4 is formed at the boundary between triangular prism portion 14d and clamping portion 14b.

[0051] Folding line FX5a is formed at the boundary between reinforcing portion 16a (extending portion 17a) and folded-back portion 15a. Folding line FX5b is formed at the boundary between reinforcing portion 16b (extending portion 17b) and folded-back portion 15b. Folding line FX6a is formed at the boundary between folded-back portion 15a and clamping portion 14a. Folding line FX6b is formed at the boundary between folded-back portion 15b and clamping portion 14a.

[0052] Folding line FX5c is formed at the boundary between reinforcing portion 16c, which is extending portion 17c, and folded-back portion 15c. Folding line FX5d is formed at the boundary between reinforcing portion 16d, which is extending portion 17d, and folded-back portion 15d. Folding line FX6c is formed at the boundary between folded-back portion 15c and clamping portion 14b. Folding line FX6d is formed at the boundary between folded-back portion 15d and clamping portion 14b.

[0053] Folding line FY1 is formed at the boundary between gusset portion 14e adjacent to folded portion 15b and sandwiching portion 14a, and at the boundary between gusset portion 14f adjacent to folded portion 15c and sandwiching portion 14b. Folding line FY2 is formed at the boundary between gusset portion 14g adjacent to folded portion 15a and sandwiching portion 14a, and at the boundary between gusset portion 14h adjacent to folded portion 15d and sandwiching portion 14b.

[0054] Folding line FY3 is formed at the boundary between sandwiching portion 14a on the back side not connected to folded-back portion 15 and gusset portion 14g, and at the boundary between sandwiching portion 14b on the back side not connected to folded-back portion 15 and gusset portion 14h. Folding line FY4 is formed at the boundary between sandwiching portion 14a on the back side not connected to folded-back portion 15 and gusset portion 14e to be overlapped and bonded thereto, and at the boundary between sandwiching portion 14b on the back side not connected to folded-back portion 15 and gusset portion 14f to be overlapped and bonded thereto.

[0055] The folding lines FX1 to FY4 are formed in the exterior film 13. The folding lines FX1 to FY4 are created in accordance with the shapes and sizes of the storage / discharge element 11 and the current collecting tab lead 12 housed in the exterior film 13. As shown in FIG. 4, the storage / discharge element 11, to which the current collecting tab leads 12a and 12b are connected, is placed on the exterior film 13 at the center portion 13a.

[0056] Next, the folding lines FY1 to FY4 extending in the Y direction are all folded back so as to form valley folds, as shown by the arrows in Fig. 4. As a result, the exterior film 13 is wrapped around the periphery of the storage / discharge element 11, as shown in Fig. 5. Then, the gusset portion 14e, the gusset portion 14f, and the portion sandwiched between the gusset portion 14e and the gusset portion 14f, which are on the far side in Fig. 5, are overlapped and welded. As a result, the exterior film 13 becomes cylindrical.

[0057] Next, the folding lines FX2 and FX3 extending in the X direction are mountain folds, and the folding lines FX1 and FX4 extending in the X direction are valley folds, and the portions that will become the clamping portions 14a and 14b that are located outside the storage / discharge element 11 in the Y direction are brought into contact with each other so as to overlap close to each other in the Z direction, as shown by the arrows in Fig. 5. At this time, the gusset portions 14e to 14h are all folded inward in the X direction. Then, the portions that will become the clamping portions 14a and 14b are overlapped and welded together with the current collecting tab leads 12a and 12b. This results in the formation of a triangular prism portion 14c, a clamping portion 14a extending outward in the Y direction from the triangular prism portion 14c, and, as shown in Figure 6, a triangular prism portion 14d, and a clamping portion 14b extending outward in the Y direction from the triangular prism portion 14d.

[0058] Next, the folded-back portions 15a-15d and the reinforcing portions 16a-16d are folded back as shown by the arrows in Fig. 6, with the folding lines FX5a-FX6d extending in the X direction as valley folds. The folded-back portions 15a-15d are brought into contact with the Y-direction ends of the clamping portions 14a and 14b, and the reinforcing portions 16a-16d are brought into contact with the Z-direction surfaces of the clamping portions 14a and 14b. The folded-back portions 15a-15d are then welded to the Y-direction ends of the clamping portions 14a and 14b, and the reinforcing portions 16a-16d are welded to the Z-direction surfaces of the clamping portions 14a and 14b. In this way, the pouch cell 10 is manufactured as shown in Fig. 1.

[0059] In this embodiment, since the folded portions 15a, 15b, the reinforcing portions 16a, and 16b can be formed simply by folding back the exterior film 13, it is possible to improve the airtightness, rigidity, and strength without increasing the number of parts. Similarly, since the folded portions 15c, 15d, the reinforcing portions 16c, and 16d can be formed simply by folding back the exterior film 13, it is possible to improve the airtightness, rigidity, and strength without increasing the number of parts.

[0060] A second embodiment of a pouch cell according to the present invention will now be described with reference to the drawings. Fig. 7 is a perspective view showing a pouch cell in this embodiment, and Fig. 8 is a development view showing an exterior film of the pouch cell in this embodiment. This embodiment differs from the above-mentioned first embodiment in terms of the reinforcing portion, and other configurations corresponding to those in the above-mentioned first embodiment are given the same reference numerals and their description will be omitted.

[0061] In this embodiment, as shown in Figs. 7 and 8, the reinforcing portion 16a has a second extending portion 17a1 extending further in the Y direction than the extending portion 17a. The second extending portion 17a1 is attached to the Z direction surface of the clamping portion 14a in the same manner as the extending portion 17a, and is further attached to the Z direction surface of the triangular prism portion 14c adjacent to the clamping portion 14a. The second extending portion 17a1 has a substantially rectangular outline. The second extending portion 17a1 has a dimension in the X direction substantially equal to that of the extending portion 17a. Similarly, the reinforcing portion 16b has a second extending portion 17b1 extending further in the Y direction than the extending portion 17b. The second extending portion 17b1 is attached to the Z direction surface of the clamping portion 14a in the same manner as the extending portion 17b, and is further attached to the Z direction surface of the triangular prism portion 14c adjacent to the clamping portion 14a. The second extending portion 17b1 has a substantially rectangular outline. The second extending portion 17b1 has a dimension in the X direction substantially equal to that of the extending portion 17b.

[0062] In this embodiment, as shown in Figs. 7 and 8, the reinforcing portion 16c has a second extending portion 17c1 extending further in the Y direction than the extending portion 17c. The second extending portion 17c1 is attached to the Z direction surface of the clamping portion 14b in the same manner as the extending portion 17c, and is further attached to the Z direction surface of the triangular prism portion 14d adjacent to the clamping portion 14b. The second extending portion 17c1 has a substantially rectangular outline. The second extending portion 17c1 has a dimension in the X direction substantially equal to that of the extending portion 17c. Similarly, the reinforcing portion 16d has a second extending portion 17d1 extending further in the Y direction than the extending portion 17d. The second extending portion 17d1 is attached to the Z direction surface of the clamping portion 14b, similar to the extending portion 17d, and is further attached to the Z direction surface of the triangular prism portion 14d adjacent to the clamping portion 14b. The second extending portion 17d1 has a substantially rectangular contour. The second extending portion 17d1 has a dimension in the X direction substantially equal to that of the extending portion 17d.

[0063] In this embodiment, since reinforcing portions 16a to 16d have second extension portions 17a1 to 17d1, it is possible to cover and reinforce the vicinity of the boundary between triangular prism portion 14c and clamping portion 14a and the vicinity of the boundary between triangular prism portion 14d and clamping portion 14b, which have room for improvement in terms of durability. As a result, the triangular prism portions 14c, 14d, which form steps where the collector tab lead 12, which has a small thickness dimension, is pulled out from the storage / discharge element 11, need to be reinforced in terms of strength and rigidity is required, but this can be satisfied.

[0064] Hereinafter, a third embodiment of a pouch cell according to the present invention will be described with reference to the drawings. Fig. 9 is a perspective view showing a pouch cell in this embodiment, Fig. 10 is a development view showing an exterior film of the pouch cell in this embodiment, and Fig. 11 is an end view showing an end of a clamping part in the pouch cell of this embodiment. This embodiment differs from the above-mentioned first embodiment in terms of the second folded part and the second reinforcing part, and other configurations corresponding to those in the above-mentioned first embodiment are given the same reference numerals and their description will be omitted.

[0065] In this embodiment, as shown in Figures 9 to 11, folded portion 15e and reinforcing portion 16e are formed by extending exterior film 13 that forms the Z-direction back surface of clamping portion 14a. Folded portion 15e is attached to the Y-direction end portion of clamping portion 14a as shown in Figures 9 to 11. Reinforcing portion 16e is attached to the Z-direction surface of clamping portion 14a as shown in Figures 9 to 11. The second folded portion 15f and the second reinforcing portion 16f are formed by extending the exterior film 13 that forms the Z-direction surface of the clamping portion 14a. The second folded portion 15f is attached to the Y-direction end of the clamping portion 14a as shown in Figures 9 to 11. The second reinforcing portion 16f is attached to the Z-direction back surface of the clamping portion 14a as shown in Figures 9 to 11.

[0066] Similarly, folded-back portion 15g and reinforcing portion 16g are formed by extending exterior film 13 that forms the Z-direction back surface of clamping portion 14b. Folded-back portion 15g is attached to the Y-direction end portion of clamping portion 14b as shown in Figures 9 to 11. Reinforcing portion 16g is attached to the Z-direction surface of clamping portion 14b as shown in Figures 9 to 11. The second folded portion 15h and the second reinforcing portion 16h are formed by extending the exterior film 13 that forms the Z-direction surface of the clamping portion 14b. The second folded portion 15h is attached to the Y-direction end portion of the clamping portion 14b as shown in Figures 9 to 11. The second reinforcing portion 16h is attached to the Z-direction back surface of the clamping portion 14b as shown in Figures 9 to 11.

[0067] The folded portion 15e and the second folded portion 15f are attached to both outer positions in the X direction of the current collecting tab lead 12a at the Y direction end of the clamping portion 14a, as shown in Fig. 9 to Fig. 11. The folded portion 15e is formed on the side of the clamping portion 14a that is close to the gusset portion 14g in the X direction, as shown in Fig. 10. The second folded portion 15f is formed on the side of the clamping portion 14a that is close to the gusset portion 14e in the X direction, as shown in Fig. 10. The folded portion 15e is attached at a position corresponding to the folded portion 15a shown in Fig. 3. The second folded portion 15f is attached at a position corresponding to the folded portion 15b shown in Fig. 3.

[0068] The folded portion 15g and the second folded portion 15h are attached to both outer positions in the X direction of the current collecting tab lead 12b at the Y direction end of the clamping portion 14b, as shown in Fig. 9 to Fig. 11. The folded portion 15g is formed on the side of the clamping portion 14b that is close to the gusset portion 14f in the X direction, as shown in Fig. 10. The second folded portion 15h is formed on the side of the clamping portion 14b that is close to the gusset portion 14h in the X direction, as shown in Fig. 10. The folded portion 15g is attached at a position corresponding to the folded portion 15c shown in Fig. 3. The second folded portion 15h is attached at a position corresponding to the folded portion 15d shown in Fig. 3.

[0069] Folded portion 15e and second folded portion 15f have substantially the same contour shape as folded portion 15a and folded portion 15b shown in Fig. 2. Folded portion 15g and second folded portion 15h have substantially the same contour shape as folded portion 15c and folded portion 15d shown in Fig. 2. Unlike the reinforcing portion 16a and the reinforcing portion 16b shown in FIG. 2, the reinforcing portion 16e and the second reinforcing portion 16f have a contour shape that is substantially the same as that of the sandwiching portion 14a. In other words, the reinforcing portion 16e and the second reinforcing portion 16f have a dimension in the X direction that is substantially the same as that of the sandwiching portion 14a. The reinforcing portion 16e extends in the Y direction from the folded portion 15e and has an extending portion 17e that is also extended in the X direction. The second reinforcing portion 16f extends in the Y direction from the second folded portion 15f and has an extending portion 17f that is also extended in the X direction.

[0070] Unlike the reinforcing portion 16c and the second reinforcing portion 16d shown in FIG. 2, the reinforcing portion 16g and the second reinforcing portion 16h have a contour shape that is approximately equal to that of the sandwiching portion 14b. In other words, the reinforcing portion 16g and the second reinforcing portion 16h have an X-direction dimension that is approximately equal to that of the sandwiching portion 14b. The reinforcing portion 16g extends in the Y-direction from the folded portion 15g and has an extending portion 17g that is also extended in the X-direction. The second reinforcing portion 16h extends in the Y-direction from the second folded portion 15h and has an extending portion 17h that is also extended in the X-direction.

[0071] A method for producing the pouch cell 10 in this embodiment will be described below.

[0072] Description of the same steps as those of the process of covering the pouch cell with the exterior film in the first embodiment shown in Figs. 4 to 6 will be omitted.

[0073] In this embodiment as well, folding lines are formed in the exterior film 13 as shown in FIG. The folding line FX5e is formed at the boundary between the reinforcing portion 16e having the extending portion 17e and the folded-back portion 15e. The folding line FX5f is formed at the boundary between the second reinforcing portion 16f having the extending portion 17f and the second folded-back portion 15f. The folding line FX6e is formed at the boundary between the folded-back portion 15e and the clamping portion 14a which is the back surface in the Z direction. The folding line FX6f is formed at the boundary between the second folded-back portion 15f and the clamping portion 14a which is the front surface in the Z direction.

[0074] The folding line FX5g is formed at the boundary between the reinforcing portion 16g having the extending portion 17g and the folded-back portion 15g. The folding line FX5h is formed at the boundary between the second reinforcing portion 16h having the extending portion 17h and the second folded-back portion 15h. The folding line FX6g is formed at the boundary between the folded-back portion 15g and the clamping portion 14b which is the back surface in the Z direction. The folding line FX6h is formed at the boundary between the second folded-back portion 15h and the clamping portion 14b which is the front surface in the Z direction.

[0075] In this embodiment as well, the exterior film 13 on which the storage / discharge element 11 is placed is formed into a cylindrical shape, and further, the clamping portion 14a and the clamping portion 14b are formed.

[0076] Next, the folded-back portion 15e to the second folded-back portion 15h and the reinforcing portion 16e to the second reinforcing portion 16h are folded back along the folding lines FX5e to FX6h extending in the X direction as valley folds, similarly to Fig. 6. The folded-back portion 15e to the second folded-back portion 15h are brought into contact with the Y-direction ends of the clamping portion 14a and the clamping portion 14b. The reinforcing portion 16e is brought into contact with the Z-direction surface of the clamping portion 14a. The reinforcing portion 16g is brought into contact with the Z-direction surface of the clamping portion 14b. The second reinforcing portion 16f is brought into contact with the Z-direction back surface of the clamping portion 14a. The second reinforcing portion 16h is brought into contact with the Z-direction back surface of the clamping portion 14b.

[0077] Then, the folded portion 15e to the second folded portion 15h are welded to the Y-direction ends of the clamping portion 14a and the clamping portion 14b, the reinforcing portion 16e is welded to the Z-direction surface of the clamping portion 14a, the reinforcing portion 16g is welded to the Z-direction surface of the clamping portion 14b, the second reinforcing portion 16f is welded to the Z-direction back surface of the clamping portion 14a, and the second reinforcing portion 16h is welded to the Z-direction back surface of the clamping portion 14b. In this way, the pouch cell 10 is manufactured as shown in FIG. 9.

[0078] This embodiment also has the same advantages as the first embodiment described above. In particular, almost the entire surface of the sandwiching portion 14 is formed from four sheets of exterior film 13 laminated in the thickness direction, which makes it possible to improve strength and rigidity. Therefore, the portion of the pouch cell 10 where the current collecting tab lead 12 is provided can be further reinforced. Moreover, the folded portion 15e and the reinforcing portion 16e, the second folded portion 15f and the second reinforcing portion 16f can be formed simply by folding back the exterior film 13, respectively, and similarly, the folded portion 15g and the reinforcing portion 16g, the second folded portion 15h and the second reinforcing portion 16h can be formed simply by folding back the exterior film 13, respectively, making it possible to improve airtightness and improve rigidity and strength without increasing the number of parts.

[0079] A fourth embodiment of a pouch cell according to the present invention will now be described with reference to the drawings. Fig. 12 is an enlarged development view showing the vicinity of the folded-back portion of the exterior film of the pouch cell in this embodiment, and Fig. 13 is an end view showing the end of the clamping portion of the pouch cell in this embodiment. This embodiment differs from the first to third embodiments described above in terms of the relief portion, which is the outline of the exterior film in the vicinity of the folded-back portion, and other configurations corresponding to the first to third embodiments described above are denoted by the same reference numerals and description thereof will be omitted.

[0080] In this embodiment, the reinforcing portion 16 is formed with a recess 18 near the boundary between the folded-back portion 15 and the extending portion 17 . As shown in Figures 12 and 13, the escape portion 18 is formed on the inside in the X direction of the folded-back portion 15, that is, near the corner of the slit formed by the clamping portion 14, the folded-back portion 15, and the reinforcing portion 16 in the developed view of the exterior film 13.

[0081] 12 and 13, the relief portion 18 has relief portion 18a1 formed by enlarging a corner between the Y-direction end of the clamping portion 14a and the X-direction inner end of the folded-back portion 15a in a developed view of the exterior film 13. The relief portion 18 has relief portion 18a2 formed by enlarging a corner between the X-direction inner end of the folded-back portion 15a and an end of the reinforcing portion 16a adjacent to the folded-back portion 15a in a developed view of the exterior film 13.

[0082] The contour of the clearance 18a1 is formed in an arc shape. The arc forming the clearance 18a1 is centered on the intersection of the Y-direction end of the clamping portion 14a and the inner X-direction end of the folded-back portion 15a in a developed view of the exterior film 13. The contour of the clearance 18a2 is formed in an arc shape. The arc forming the clearance 18a2 is centered on the intersection of the inner end of the folded-back portion 15a in the X direction and the end of the reinforcing portion 16a that is adjacent to the folded-back portion 15a in a developed view of the exterior film 13.

[0083] 12 and 13, the relief portion 18 has relief portion 18b1 formed by enlarging a corner between the Y-direction end of the clamping portion 14a and the X-direction inner end of the folded-back portion 15b in a developed view of the exterior film 13. The relief portion 18 has relief portion 18b2 formed by enlarging a corner between the X-direction inner end of the folded-back portion 15a and an end of the reinforcing portion 16b adjacent to the folded-back portion 15b in a developed view of the exterior film 13.

[0084] The contour of the clearance 18b1 is formed in an arc shape. The arc forming the clearance 18b1 is centered on the intersection of the Y-direction end of the clamping portion 14a and the inner X-direction end of the folded-back portion 15b in a developed view of the exterior film 13. The contour of the clearance 18b2 is formed in an arc shape. The arc forming the clearance 18b2 has its center at the intersection of the inner end of the folded-back portion 15b in the X direction and the end of the reinforcing portion 16b adjacent to the folded-back portion 15b in a developed view of the exterior film 13. In FIG. 13, the recess 18 is shown diagrammatically.

[0085] The clearance portions 18a1 and 18a2 can be formed to have shapes symmetrical to each other in the Y direction. The clearance portions 18b1 and 18b2 can also be formed to have shapes symmetrical to each other in the Y direction. Furthermore, the clearance portions 18a1 and 18b1 can be formed to have shapes symmetrical to each other in the X direction. The clearance portions 18a2 and 18b2 can be formed to have shapes symmetrical to each other in the X direction.

[0086] Similarly, the recess 18 is formed in the folded portion 15c and the folded portion 15d.

[0087] By forming the clearance 18a1, a corner of the slit in a developed view of the exterior film 13 is separated from a corner of the current collecting tab lead 12a. By forming the clearance 18a2, a corner of the slit in a developed view of the exterior film 13 is separated from a corner of the current collecting tab lead 12a. By forming the clearances 18a1 and 18a2, a protrusion 15a3 is formed at the inner end of the folded portion 15a in the X direction.

[0088] By forming the clearance 18b1, the corners of the slits in the developed view of the exterior film 13 are spaced apart from the corners of the current collecting tab lead 12a. By forming the clearance 18b2, the corners of the slits in the developed view of the exterior film 13 are spaced apart from the corners of the current collecting tab lead 12a.

[0089] By forming the clearances 18b1 and 18b2, a protrusion 15b3 is formed at the inner end of the folded portion 15a in the X direction, similar to the protrusion 15a3. As a result, when the exterior film 13 is brought into close contact with the vicinity of the Y-direction end of the clamping portion 14a, the exterior film 13 can be separated from the current collecting tab lead 12a so that the current collecting tab lead 12a drawn out from the Y-direction end of the clamping portion 14a does not hinder the adhesion of the folded-back portion 15a, the reinforcing portion 16a, the folded-back portion 15b, and the reinforcing portion 16b to the clamping portion 14a. As a result, even if the protruding portion 15b3 is not in close contact with the Y-direction end of the clamping portion 14a, it is possible to maintain adhesion in other portions.

[0090] Similarly, by forming the clearances 18 in the folded-back portions 15c and 15d, the exterior film 13 can be separated from the current collecting tab lead 12b when the exterior film 13 is adhered closely to the Y-direction end portion of the clamping portion 14b. This makes it possible to prevent the current collecting tab lead 12 from hindering the close contact of the reinforcing portion 16 with the clamping portion 14 near the boundary between the folded-back portion 15 and the extending portion 17. It is possible to further improve the airtightness at the Y-direction end portion of the clamping portion 14 where the current collecting tab lead 12 is drawn out to the outside.

[0091] This embodiment can also achieve the same effects as the above-described embodiments.

[0092] In this embodiment, the contour of the recess 18 is formed in an arc shape, but the present invention is not limited to this configuration. For example, the outline of the recess 18 may be rectangular as shown in Fig. 14. Alternatively, the recess 18a1 and the recess 18a2 may be continuous to form an elliptical shape as shown in Fig. 15. In this case, no protrusion is formed. Furthermore, as shown in FIG. 16, a linear relief portion 18 can also be formed.

[0093] Hereinafter, a fifth embodiment of a pouch cell according to the present invention will be described with reference to the drawings. Fig. 17 is a perspective view showing a pouch cell in this embodiment, Fig. 18 is a development view showing an exterior film of the pouch cell in this embodiment, and Fig. 19 is a schematic diagram showing a triangular prism-shaped portion in the pouch cell of this embodiment. This embodiment differs from the above-mentioned first to fourth embodiments in terms of the folded-back portion and the reinforcing portion, and other configurations corresponding to the above-mentioned first to fourth embodiments are given the same reference numerals and their description will be omitted.

[0094] In this embodiment, as shown in Figures 17 and 18, the folded portion 15j and the reinforcing portion 16j are formed by extending in the X direction the exterior film 13 that forms the Z-direction back surface of the clamping portion 14a. As shown in Figures 17 and 18, the folded portion 15j is attached to the X-direction end portion of the clamping portion 14a. As shown in Figures 17 and 18, the reinforcing portion 16j is attached to the Z-direction surface of the clamping portion 14a. Similarly, folded portion 15k and reinforcing portion 16k are formed by extending in the X direction exterior film 13 that forms the Z-direction back surface of clamping portion 14b. Folded portion 15k is attached to the Y-direction end portion of clamping portion 14b as shown in Figs. 17 and 18. Reinforcing portion 16k is attached to the Z-direction surface of clamping portion 14b as shown in Figs. 17 and 18.

[0095] Folded portion 15j and folded portion 15k are attached to one outer position in the X direction of current collecting tab lead 12a at the Y direction end of clamping portion 14a, as shown in Fig. 17 and Fig. 18. Folded portion 15j is formed on the side of clamping portion 14a close to gusset portion 14e in the X direction, as shown in Fig. 18. As shown in FIG. 18, the folded-back portion 15k is formed on the side of the sandwiching portion 14a adjacent to the gusset portion 14f in the X direction.

[0096] In this embodiment as well, folding lines are formed in the exterior film 13 as shown in FIG. Folding lines FY1 extend outward in both Y directions compared to the configurations of the above-described embodiments shown in Figures 2, 8, and 10. Folding lines FY1 form the X-direction ends of clamping portion 14a and clamping portion 14b. Both ends of folding line FY1 in the Y direction are formed at the boundary between clamping portion 14a and folded-back portion 15j and at the boundary between clamping portion 14b and folded-back portion 15k.

[0097] The folding line FY5j is formed at the boundary between the reinforcing portion 16j having the extending portion 17j and the folded-back portion 15j. The folding line FY5j extends in the Y direction and is formed parallel to the folding line FY1. The folding line FY5k is formed at the boundary between the reinforcing portion 16k having the extending portion 17k and the folded-back portion 15k. The folding line FY5k extends in the Y direction and is formed parallel to the folding line FY1.

[0098] In this embodiment as well, the exterior film 13 on which the storage / discharge element 11 is placed is formed into a cylindrical shape, and further, the clamping portion 14a and the clamping portion 14b are formed.

[0099] Next, fold-back portion 15j, fold-back portion 15k, reinforcing portion 16j, and reinforcing portion 16k are folded back as shown in Fig. 6, with folding lines FY1 to FY5k extending in the Y direction as valley folds. Reinforcing portion 16j is brought into contact with the Z-direction surface of clamping portion 14a. Reinforcing portion 16k is brought into contact with the Z-direction surface of clamping portion 14b.

[0100] Then, the folded-back portions 15j and 15k are welded to the X-direction ends of the clamping portions 14a and 14b, the reinforcing portion 16j is welded to the Z-direction surface of the clamping portion 14a, and the reinforcing portion 16k is welded to the Z-direction surface of the clamping portion 14b. In this way, the pouch cell 10 is manufactured as shown in FIG.

[0101] In this embodiment, the folded portion 15j and the reinforcing portion 16j, and the folded portion 15k and the reinforcing portion 16k are wrapped around the clamping portion 14a and the clamping portion 14b from their ends in the X direction to cover them, respectively. That is, the folded-back portion 15 is formed at a position that becomes a side portion of the clamping portion 14 in the pull-out direction of the current collecting tab lead 12. As a result, the reinforcing portion 16j is welded by wrapping around the clamping portion 14a from the side surface in the X direction in the vicinity of the portion where the thickness increases from the clamping portion 14a to the triangular prism portion 14c. At the same time, the reinforcing portion 16k is welded by wrapping around the clamping portion 14b from the side surface in the X direction in the vicinity of the portion where the thickness increases from the clamping portion 14b to the triangular prism portion 14d.

[0102] Here, when the clamping portion 14 is pulled outward in the Y direction, an external force acts near the triangular prism portions 14c, 14d, as shown by the arrows in Fig. 19, to separate the Z-direction front and back surfaces of the triangular prism portions 14c, 14d from each other. The welded portion of the clamping portion 14 may peel off due to this external force, but this embodiment can prevent this.

[0103] This embodiment can also achieve the same effects as the above-described embodiments.

[0104] In this embodiment, the folded portion 15j and the folded portion 15k are connected to one end of the clamping portion 14a and the clamping portion 14b in the X direction, but the present invention is not limited to this configuration. FIG. 20 is an end view showing an end of a clamping portion in another example of a pouch cell in this embodiment.

[0105] For example, as shown in Fig. 20, a second folded-back portion 15j1 may be formed on the opposite side of the clamping portion 14a in the X direction from the folded-back portion 15j, and a second reinforcing portion 16j1 may be welded to the rear surface of the clamping portion 14a in the Z direction. In this case, the second reinforcing portion 16j1 may have an X-direction length that does not affect the exterior film 13 that is the front surface of the clamping portion 14a, as shown in Fig. 18. This allows the reinforcing portion 16 to be wrapped around both ends of the clamping portion 14a in the X direction, further preventing the triangular prism portion 14c from peeling off. The clamping portion 14b can also have a similar structure.

[0106] 18, the X-direction length of the reinforcing portion 16j may be made greater than the X-direction length of the clamping portion 14a, and the remaining reinforcing portion 16j after being welded to the Z-direction front surface of the clamping portion 14a may be welded to the Z-direction back surface of the clamping portion 14a. In this case as well, the reinforcing portion 16 may be wrapped around both ends of the clamping portion 14a in the X direction.

[0107] A pouch cell according to a sixth embodiment of the present invention will now be described with reference to the drawings. 21 is a development view showing an exterior film of a pouch cell in this embodiment. This embodiment differs from the above-mentioned first to fifth embodiments in terms of the folded-back portion and the reinforcing portion, and other configurations corresponding to the above-mentioned first to fifth embodiments are given the same reference numerals and description thereof will be omitted.

[0108] As shown in FIG. 21, this embodiment has folded portions 15j2, 15j3, 15k2, and 15k3 in addition to the other example of the fifth embodiment. The folded portions 15j2, 15j3, 15k2, and 15k3 are welded to the Y-direction ends of the clamping portion 14a and the clamping portion 14b.

[0109] The folded portion 15j2 is welded at a position corresponding to the folded portion 15b. The folded portion 15k2 is welded at a position corresponding to the folded portion 15c. The folded portion 15j2 has a contour shape substantially equal to that of the folded portion 15b. The folded portion 15k2 has a contour shape substantially equal to that of the folded portion 15c.

[0110] The folded portion 15j3 is welded to a position corresponding to a part of the folded portion 15a. The folded portion 15j3 is welded to a position on the side of the folded portion 15a that is close to the current collecting tab lead 12a. The X-direction length of the folded portion 15j3 is set to be smaller than the X-direction length of the folded portion 15a by the X-direction length of the second reinforcing portion 16j1.

[0111] The folded portion 15k3 is welded to a position corresponding to a part of the folded portion 15b. The folded portion 15k3 is welded to a position on the side of the folded portion 15b that is close to the current collecting tab lead 12b. The X-direction length of the folded portion 15k3 is set smaller than the X-direction length of the folded portion 15b by the X-direction length of the second reinforcing portion 16k1.

[0112] In this embodiment as well, folding lines are formed in the exterior film 13 as shown in FIG.

[0113] The folding line FY5j1 is formed at the boundary between the reinforcing portion 16j and the second folded portion 15j1. The folding line FY5j1 extends in the Y direction and is formed parallel to the folding line FY5j. The folding line FY5j2 is formed at the boundary between the second folded portion 15j1 and the second reinforcing portion 16j1. The folding line FY5j2 extends in the Y direction and is formed parallel to the folding line FY5j. The folding line FY5k1 is formed at the boundary between the reinforcing portion 16k and the second folded portion 15k1. The folding line FY5k1 extends in the Y direction and is formed parallel to the folding line FY5k. The folding line FY5k2 is formed at the boundary between the second folded portion 15k1 and the second reinforcing portion 16k1. The folding line FY5k2 extends in the Y direction and is formed parallel to the folding line FY5k.

[0114] The folding line FX5j1 is formed at the boundary between the reinforcing portion 16j and the folded-back portion 15j2. The folding line FX5j1 extends in the X direction and is formed parallel to the folding line FX1. The folding line FX5j2 is formed at the boundary between the reinforcing portion 16j and the folded-back portion 15j3. The folding line FX5j2 extends in the X direction and is formed parallel to the folding line FX1. The folding line FX5k1 is formed at the boundary between the reinforcing portion 16k and the folded-back portion 15k2. The folding line FX5k1 extends in the X direction and is formed parallel to the folding line FX1. The folding line FX5k2 is formed at the boundary between the reinforcing portion 16k and the folded-back portion 15k3. The folding line FX5k2 extends in the X direction and is formed parallel to the folding line FX1.

[0115] In this embodiment as well, the exterior film 13 on which the storage / discharge element 11 is placed is formed into a cylindrical shape, and further, the clamping portion 14a and the clamping portion 14b are formed.

[0116] Next, fold-back portion 15j, fold-back portion 15k, reinforcing portion 16j, and reinforcing portion 16k are folded back as shown in Fig. 6, with folding lines FY1 to FY5k extending in the Y direction as valley folds. Reinforcing portion 16j is brought into contact with the Z-direction surface of clamping portion 14a. Reinforcing portion 16k is brought into contact with the Z-direction surface of clamping portion 14b. Furthermore, the second folded portion 15j1, the second folded portion 15k1, the second reinforcing portion 16j1, and the second reinforcing portion 16k1 are folded back around the folding lines FY5j1-FY5k2 extending in the Y direction as valley folds. The second reinforcing portion 16j1 is brought into contact with the Z-direction back surface of the clamping portion 14a. The second reinforcing portion 16k1 is brought into contact with the Z-direction back surface of the clamping portion 14b.

[0117] Then, folded portion 15j, folded portion 15k, second folded portion 15j1, and second folded portion 15k1 are welded to the X-direction ends of clamping portion 14a and clamping portion 14b, reinforcing portion 16j and reinforcing portion 16k are welded to the Z-direction surfaces of clamping portion 14a and clamping portion 14b, and second reinforcing portion 16j1 and second reinforcing portion 16k1 are welded to the Z-direction back surfaces of clamping portion 14a and clamping portion 14b. Furthermore, the folding lines FX5j1 to FX5k2 extending in the X direction are folded as valley folds, and the folded-back portions 15j2, 15j3, 15k2, and 15k3 are brought into contact with the Y-direction ends of the clamping portions 14a and 14b, and then welded to each other. In this way, the pouch cell 10 is manufactured.

[0118] According to this embodiment, like the other examples of the fifth embodiment, peeling of the exterior film 13 near the boundary between the triangular prism portion 14c and the clamping portion 14a, and between the triangular prism portion 14d and the clamping portion 14b can be prevented. At the same time, the folded-back portions 15j2, 15j3, 15k2, and 15k3 can improve the airtightness and strength at the Y-direction ends of the clamping portion 14a and the clamping portion 14b. Furthermore, the Z-direction dimension of the attached folded portions 15j2, 15j3, 15k2, and 15k3 can be made larger than the Z-direction thickness dimension at the Y-direction ends of clamping portions 14a and 14b, and the folded portions can be attached overlappingly to the Z-direction back surfaces of clamping portions 14a and 14b to further improve strength.

[0119] Furthermore, in the present invention, the respective configurations in the above-mentioned embodiments may be combined individually, or a configuration in which a specific configuration is removed may be adopted. For example, the folded parts 15j2, 15j3, 15k2, and 15k3 in the sixth embodiment are an example in which the folded parts 15a to 15d in the first embodiment are modified and combined with the fifth embodiment. In this way, the individual configurations may be combined separately. Furthermore, when it is desired to increase the thickness dimension at the clamping portion 14, it is preferable to increase the number of layers of the exterior film 13 attached to the clamping portion 14, and when it is desired to decrease the thickness dimension at the clamping portion 14, it is preferable to decrease the number of layers of the exterior film 13 attached to the clamping portion 14. [Industrial Applicability]

[0120] An example of the application of the present invention is a battery cell used in a vehicle. The requirements for a vehicle battery are that it must be able to withstand a wide range of disturbances, such as various climates, temperatures, altitudes, rough roads, and vibrations caused by collisions. For this reason, the battery cell must have a higher level of resistance to moisture from the atmosphere, gas permeability, and vibration resistance than a consumer battery. However, for consumer use, examples include packaging for food products that require long-term storage, in which case the welded parts can be used to hold the product, for example by drilling holes in the welded parts and hanging the product for display. [Explanation of symbols]

[0121] 10…Pouch cell 11...Charge and discharge element 12...Current collector tab lead 13…Exterior film 14...Holding part 15…Folded section 15f, 15h, 15j1, 15k1...Second fold 16…Reinforcement 16f,16h,16j1,16k1…Second reinforcement part 17...Extension part 17a1~17d1…Second extension part 18...Relief area FX1~FY5k2…Folding line

Claims

1. a substantially rectangular parallelepiped storage / discharge element (11); a current collecting tab lead (12) that is thinner than the storage / discharge element (11) and is pulled out from the storage / discharge element (11); and an exterior film (13) that packages the storage / discharge element (11) with the current collecting tab lead (12) pulled out to the outside; A pouch cell (10) comprising: The exterior film (13) has a clamping portion (14) that clamps the current collecting tab lead (12) from the front and back sides in the thickness direction, a folded-back portion (15) that follows the contour of the clamping portion (14), and a reinforcing portion (16) that is folded back from the folded-back portion (15) and joined to at least the clamping portion (14), The folded portion (15) is joined to a side portion extending in the thickness direction of the clamping portion (14), The reinforcing portion (16) is folded back by the folded back portion (15) in a direction in which the current collecting tab lead (12) is sandwiched therebetween, The reinforcing portion (16) has an extension portion (17) extending from the folded portion (15) along a direction in which the current collecting tab lead (12) is pulled out or along a direction intersecting the direction. A pouch cell characterized by:

2. The reinforcing portion (16) has a second extending portion (17a1 to 17d1) that is attached closer to the storage / discharge element (11) than the clamping portion (14).

2. The pouch cell according to claim 1 .

3. In the reinforcing portion (16), a relief portion (18) is formed near the boundary between the folded portion (15) and the extending portion (17) so that the current collecting tab lead (12) pulled out from the clamping portion (14) does not hinder the close contact of the reinforcing portion (16) with the clamping portion (14).

3. The pouch cell according to claim 1 or 2.

4. the exterior film (13) has a second folded-back portion (15f, 15h) that follows the contour of the clamping portion (14), and a second reinforcing portion (16f, 16h) that is folded back from the second folded-back portion (15f, 15h) and joined to at least a surface of the clamping portion (14) opposite to the reinforcing portion (16), The second folded portion (15f, 15h) is joined to a side portion extending in a thickness direction of the clamping portion (14), The second reinforcing portion (16f, 16h) is folded back by the second folded back portion (15f, 15h) in a direction in which the current collecting tab lead (12) is sandwiched therebetween.

4. The pouch cell according to claim 1, wherein the pouch cell is a casing.

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