Battery

Abstract

A battery is provided with a battery element having a positive electrode, a negative electrode, and a separator, and a film having a first housing part covering one side of the battery element, and a second housing part covering the other side of the battery element opposite to the one side, a portion of the film folded back from one of the first housing portion and the second housing portion toward the other is provided with a recessed portion that is recessed toward the battery element and extends in one direction orthogonal to a direction from the one side toward the other side of the battery element. The depth of the recessed portion becomes shallower in the one direction as the recessed portion is away from the center of the battery element. According to the present invention, the fracture resistance of the film can be improved.

Description

[0001] This application is a divisional application of the Chinese patent application with the application date of November 26, 2020, application number 202080084204.1, and invention name "Battery, Thin Film Manufacturing Method and Battery Manufacturing Method". Technical Field

[0002] The present invention relates to a battery, a method for manufacturing a thin film, and a method for manufacturing a battery. Background Art

[0003] In recent years, non-aqueous electrolyte secondary batteries, especially lithium ion secondary batteries, have been developed. Lithium ion secondary batteries have a battery element having a positive electrode, a negative electrode and a separator. The positive electrode and the negative electrode are separated by a separator. The battery element is wrapped with a film.

[0004] Patent document 1 describes an example of a film. In the film, in order to avoid wrinkles on the film when a large battery element is covered with the film, a recessed portion on one side of the battery element and another recessed portion on the other side of the opposite side of the one side of the battery element are provided on the film. The two recessed portions are formed by arranging a film between a die and two punches and pressing the two punches into the die. When the two punches are pressed into the die, the film is clamped by the ribs and the die in the thickness direction of the film between the two punches.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2004-71301 Summary of the invention

[0008] Problems to be solved by the invention

[0009] As described in Patent Document 1, two recesses are sometimes formed on a film. For example, in Patent Document 1, as described above, when two recesses are formed on a film by pressing two punches into a die through the film, a force is applied to the film from both sides of the film in the thickness direction of the film between the two punches. However, the inventors have found that this method may affect the fracture resistance of the film.

[0010] One example of the purpose of the present invention is to improve the fracture resistance of a film. Other purposes of the present invention will become clear from the description of this specification.

[0011] Solutions to Solve Problems

[0012] One embodiment of the present invention is a battery comprising a battery element and a thin film, wherein the battery element has a positive electrode, a negative electrode and a separator, the thin film has a first housing portion covering one side of the battery element and a second housing portion covering the other side of the battery element opposite to the one side, and a recess is provided in a portion of the thin film folded back from one of the first housing portion and the second housing portion toward the other side, the recess is recessed toward the battery element, and extends in a direction orthogonal to a direction from the one side toward the other side of the battery element.

[0013] Another aspect of the present invention is a method for manufacturing a film, comprising the steps of: placing a film between a first mold having a first opening and a second opening and a second mold having a first module and a second module, forming a first receiving portion on the film by allowing the first module of the second mold to enter the first opening of the first mold, and forming a second receiving portion on the film by allowing the second module of the second mold to enter the second opening of the first mold.

[0014] The first mold has a protrusion, which is located between the first opening and the second opening, and has a front end that is bent into a convex shape toward the front of the front end.

[0015] The step of forming the first and second housing portions includes a step of bringing the film into contact with the tip of the protrusion of the first mold without applying pressure to the film from the side opposite to the protrusion of the first mold.

[0016] Another embodiment of the present invention is a method for manufacturing a battery, comprising the method for manufacturing a film of the above-mentioned embodiment and the following steps, namely: folding the film from one of the first housing portion and the second housing portion toward the other, using the first housing portion of the film to cover one side of a battery element having a positive electrode, a negative electrode and a separator, and using the second housing portion of the film to cover the other side of the battery element opposite to the above-mentioned one side.

[0017] Effects of the Invention

[0018] According to the above aspect of the present invention, the fracture resistance of the film can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a top view of the battery according to the embodiment.

[0020] Figure 2 yes Figure 1 A side view of the battery is shown.

[0021] Figure 3 yes Figure 1AA′ cross-section diagram.

[0022] Figure 4 yes Figures 1 to 3 An exploded perspective view of an example of a battery element shown.

[0023] Figure 5 Is used for manufacturing (processing) Figures 1 to 4 A top view of a thin-film battery device is shown.

[0024] Figure 6 yes Figure 5 BB′ cross-section diagram.

[0025] Figure 7 yes Figure 6 Magnified view of the area α surrounded by the dotted line in FIG.

[0026] Figure 8 It is used to illustrate the use of Figures 5 to 7 The diagram is a diagram of an example of a method for wrapping a battery element with a thin film (i.e., a method for manufacturing a battery) by manufacturing (processing) the device shown.

[0027] Fig. 9 It is a diagram for explaining the method of producing (processing) a thin film of a comparative example.

[0028] Fig.10 It is a figure for demonstrating the position where the thickness of a thin film was measured.

[0029] Explanation of symbols

[0030] 10: battery, 100: battery element, 110: positive electrode, 112: first wire, 120: negative electrode, 122: second wire, 130: diaphragm, 200: film, 210: first receiving portion, 220: second receiving portion, 232: recess, 300: device, 310: first mold, 312: first opening, 314: second opening, 316: protrusion, 320: second mold, 322: first module, 322a: first curved surface, 324: second module, 324a: second curved surface, 330: third module, 400: stopper. DETAILED DESCRIPTION

[0031] Hereinafter, the embodiments of the present invention will be described using the drawings. It should be noted that in all the drawings, the same components are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

[0032] In this specification, unless otherwise specified, ordinal numbers such as "first", "second", and "third" are used only to distinguish components with the same name and do not mean specific characteristics of the components (for example, order or importance).

[0033] Figure 1 It is a top view of the battery 10 according to the embodiment. Figure 2 yes Figure 1 A side view of battery 10 is shown. Figure 3 yes Figure 1 AA′ cross-section diagram. Figure 4 yes Figures 1 to 3 An exploded perspective view of an example of a battery element 100 is shown.

[0034] exist Figures 1 to 4 , the first direction X is the longitudinal direction of the battery 10 (battery element 100). The positive direction of the first direction X (the direction indicated by the arrow indicating the first direction X) is the direction from the second lead 122 described later toward the first lead 112 described later. The negative direction of the first direction X (the opposite direction to the direction indicated by the arrow indicating the first direction X) is the direction from the first lead 112 toward the second lead 122. The second direction Y is a direction intersecting the first direction X, specifically, a direction orthogonal to the first direction X, and is the width direction of the battery 10 (battery element 100). The positive direction of the second direction Y (the direction indicated by the arrow indicating the second direction Y) is the right direction of the battery 10 when the battery 10 is viewed from the positive direction of the first direction X. The negative direction of the second direction Y (the opposite direction to the direction indicated by the arrow indicating the second direction Y) is the left direction of the battery 10 when the battery 10 is viewed from the positive direction of the first direction X. The third direction Z is a direction intersecting both the first direction X and the second direction Y, specifically, a direction orthogonal to both the first direction X and the second direction Y, and is a thickness (height) direction of the battery 10 (battery element 100). The positive direction of the third direction Z (the direction indicated by the arrow indicating the third direction Z) is the upward direction of the battery 10. The negative direction of the third direction Z (the opposite direction to the direction indicated by the arrow indicating the third direction Z) is the downward direction of the battery 10.

[0035] In the present embodiment, the battery 10 is a lithium ion secondary battery, but the battery 10 may be a battery other than a lithium ion secondary battery.

[0036] use Figure 3The outline of the battery 10 is described. The battery 10 includes a battery element 100 and a film 200. The battery element 100 has a positive electrode 110, a negative electrode 120, and a separator 130. The film 200 has a first housing portion 210 and a second housing portion 220. The first housing portion 210 covers one side of the battery element 100 (the positive direction side of the third direction Z). The second housing portion 220 covers the other side of the battery element 100 opposite to the above-mentioned one side (the negative direction side of the third direction Z). A recess 232 is formed in a portion of the film 200 that is folded back from one of the first housing portion 210 and the second housing portion 220 toward the other side. The recess 232 is recessed toward the battery element 100 (toward the negative direction of the second direction Y). In addition, the recess 232 is along a direction (first direction X (for example, the negative direction of the third direction Z)) orthogonal to the direction from the above-mentioned one side toward the above-mentioned other side in the battery element 100. Figure 1 or Figure 2 ))extend.

[0037] The concave portion 232 of the film 200 is formed by using Figures 5 to 8 As described later, by using Figures 5 to 8 The film 200 produced by the described method has high fracture resistance.

[0038] use Figures 1 to 4 , the details of the battery 10 will be described.

[0039] The battery element 100 includes a plurality of positive electrodes 110, a plurality of negative electrodes 120, and a plurality of separators 130. Figure 4 As shown, in the present embodiment, a plurality of positive electrodes 110 and a plurality of negative electrodes 120 are alternately arranged along the third direction Z in a manner that a separator 130 is arranged between adjacent positive electrodes 110 and negative electrodes 120. That is, the battery element 100 becomes a laminate having a plurality of positive electrodes 110, a plurality of negative electrodes 120 and a plurality of separators 130 stacked on each other. However, the structure of the battery element 100 is not limited thereto. For example, the separator 130 may also be folded back along the second direction Y on the outside of the positive electrode 110 or the negative electrode 120 in the second direction Y, and repeatedly folded and extended in a manner passing between adjacent positive electrodes 110 and negative electrodes 120. Alternatively, the battery element 100 may also have only one positive electrode 110, only one negative electrode 120 and only one separator 130. Alternatively, at least one positive electrode 110, at least one negative electrode 120 and at least one separator 130 may also be wound.

[0040] The positive electrode 110 and the negative electrode 120 are connected to the first lead 112 and the second lead 122, respectively. Figure 1 and Figure 2As shown, in this embodiment, the first lead 112 and the second lead 122 are located on opposite sides of each other in the first direction X. However, the first lead 112 and the second lead 122 may also be located on the same side of each other in the first direction X (for example, the positive direction side of the first direction X or the negative direction side of the first direction X).

[0041] The film 200 accommodates the battery element 100 together with an electrolyte solution (not shown). That is, the film 200 functions as an outer packaging material.

[0042] The film 200 includes, for example, a heat-fusible resin layer and a barrier layer, and may be, for example, a laminated film including the heat-fusible resin layer and the barrier layer. The resin material forming the heat-fusible resin layer may be, for example, polyethylene (PE), polypropylene, nylon, polyethylene terephthalate (PET), etc. The barrier layer has, for example, a barrier property of preventing leakage of electrolyte or intrusion of moisture from the outside, and may be, for example, a barrier layer formed of a metal such as stainless steel (SUS) foil, aluminum foil, aluminum alloy foil, copper foil, titanium foil, etc.

[0043] The film 200 is folded back from one of the upper surface (the surface on the positive direction side of the third direction Z) and the lower surface (the surface on the negative direction side of the third direction Z) of the battery element 100 to the other, on the right side (the positive direction side of the second direction Y) of the battery element 100. A recessed portion 232 is formed in a portion of the folded back portion of the film 200 that covers the right side (the surface on the positive direction side of the second direction Y) of the battery element 100. The film 200 is folded back in a region that is closer to the front side (the positive direction side of the first direction X) than the front surface (the surface on the positive direction side of the first direction X) of the battery element 100 so as to sandwich the first lead 112 in the third direction Z. In addition, in this region, the fold of the film 200 (the end of the film 200 on the positive direction side of the second direction Y) protrudes to the right side (the positive direction side of the second direction Y) than the right side (the surface on the positive direction side of the second direction Y) of the battery element 100. In a region on the rear side (negative direction side of the first direction X) of the rear surface (the surface on the negative direction side of the first direction X) of the battery element 100, the film 200 is folded back so as to sandwich the second lead 122 in the third direction Z. In addition, in this region, the fold of the film 200 (the end of the film 200 on the positive direction side of the second direction Y) protrudes to the right side (positive direction side of the second direction Y) of the battery element 100.

[0044] In the region to the left (negative direction side of the second direction Y) of the folded back portion of the film 200 (the end portion of the film 200 on the positive direction side of the second direction Y), a portion of the film 200 (a portion covering the upper surface of the battery element 100 (the surface on the positive direction side of the third direction Z) and the surrounding portion thereof) overlaps with another portion of the film 200 (a portion covering the lower surface of the battery element 100 (the surface on the negative direction side of the third direction Z) and the surrounding portion thereof) in the third direction Z. As viewed from the third direction Z, the portion of the film 200 and the other portion of the film 200 are bonded to each other, for example, by welding, except for a portion overlapping with the first lead 112 or the second lead 122 in the region surrounding the battery element 100. Thus, the battery element 100 is sealed by the film 200.

[0045] like Figure 3 As shown, the recess 232 is curved into a convex shape toward the battery element 100 (toward the negative direction of the second direction Y). The curved shape of the recess 232 is determined by the curved shape of the front end of the protrusion 316 described later. In addition, the recess 232 has a depth D. The depth D of the recess 232 is the distance in the second direction Y between the most protruding portion of the film 200 that covers the right side surface of the battery element 100 (the surface on the positive direction side of the second direction Y) and faces the right side of the battery element 100 (the positive direction side of the second direction Y) and the most concave portion of the film 200 that covers the right side surface of the battery element 100 (the surface on the positive direction side of the second direction Y) and faces the battery element 100 side (the negative direction side of the second direction Y).

[0046] like Figure 2 As shown in FIG. 1 , when viewed from the right side (positive side of the second direction Y) of the battery 10, the recess 232 extends continuously along the first direction X from one side between the front surface (the surface on the positive side of the first direction X) or its vicinity of the battery element 100 and the rear surface (the surface on the negative side of the first direction X) or its vicinity of the battery element 100. The depth D of the recess 232 becomes shallower as it moves away from the center of the battery element 100 in the first direction X. This is because, on the front side (positive side of the first direction X) and the rear side (negative side of the first direction X) of the battery element 100, the fold of the film 200 (the end of the film 200 on the positive side of the second direction Y) extends further to the right side (positive side of the second direction Y) than the right side surface (the surface on the positive side of the second direction Y) of the battery element 100, and thus the portion of the film 200 covering the right side surface (the surface on the positive side of the second direction Y) of the battery element 100 is stretched toward the positive direction of the second direction Y.

[0047] Figure 5 is used Figures 1 to 4 A top view of an apparatus 300 for manufacturing (processing) a thin film 200 for a battery 10 is illustrated. Figure 6 yes Figure 5 BB′ cross-section diagram. Figure 7 yes Figure 6 Magnified view of the area α surrounded by the dotted line in FIG.

[0048] exist Figures 5 to 7 , the fourth direction P is the length direction of each of the first module 322 and the second module 324 described later. When viewed from the negative direction of the fifth direction Q described later, the positive direction of the fourth direction P (the direction indicated by the arrow indicating the fourth direction P) is the right direction of each of the first module 322 and the second module 324. When viewed from the negative direction of the fifth direction Q described later, the negative direction of the fourth direction P (the opposite direction to the direction indicated by the arrow indicating the fourth direction P) is the left direction of each of the first module 322 and the second module 324. The fifth direction Q is a direction intersecting with the fourth direction P, specifically, a direction orthogonal to the fourth direction P, and is the width direction of each of the first module 322 and the second module 324. The positive direction of the fifth direction Q (the direction indicated by the arrow indicating the fifth direction Q) is the direction from the second module 324 toward the first module 322. The negative direction of the fifth direction Q (the opposite direction to the direction indicated by the arrow indicating the fifth direction Q) is the direction from the first module 322 toward the second module 324. The sixth direction R is a direction intersecting both the fourth direction P and the fifth direction Q, specifically, a direction orthogonal to both the fourth direction P and the fifth direction Q, and is a thickness (height) direction of the first module 322 and the second module 324. The positive direction of the sixth direction R (the direction indicated by the arrow indicating the sixth direction R) is a direction from the first mold 310 described later toward the second mold 320 (upward direction). The negative direction of the sixth direction R (the opposite direction to the direction indicated by the arrow indicating the sixth direction R) is a direction from the second mold 320 toward the first mold 310 (downward direction).

[0049] use Figures 5 to 7, an overview of an example of a method for manufacturing (processing) the film 200 is described. The film 200 is manufactured using an apparatus 300. The apparatus 300 includes a first mold 310 and a second mold 320. The first mold 310 includes a first opening 312, a second opening 314, and a protrusion 316. The protrusion 316 is located between the first opening 312 and the second opening 314. The front end (upper end) of the protrusion 316 (the end on the positive direction side of the sixth direction R) is bent into a convex shape toward the front (upper end) of the front end of the protrusion 316 (the positive direction of the sixth direction R). The second mold 320 includes a first module 322 and a second module 324. The manufacturing (processing) method of the film 200 includes the following steps: placing the film 200 between the first mold 310 and the second mold 320, forming the first receiving portion 210 (first recess) in the film 200 by allowing the first module 322 of the second mold 320 to enter the first opening 312 of the first mold 310, and forming the second receiving portion 220 (second recess) in the film 200 by allowing the second module 324 of the second mold 320 to enter the second opening 314 of the first mold 310. The step of forming the first receiving portion 210 and the second receiving portion 220 includes a step of bringing the film 200 into contact with the front end of the protrusion 316 of the first mold 310 without applying pressure to the film 200 from the opposite side of the protrusion 316 of the first mold 310 (the upper side of the protrusion 316, i.e., the positive direction side of the sixth direction R of the protrusion 316).

[0050] use Figures 5 to 7 , the details of the manufacturing (processing) method of the film 200 are described.

[0051] exist Figures 5 to 7 In the embodiment, the first mold 310 is a punching die, and the first module 322 and the second module 324 are punches respectively.

[0052] First, the film 200 is placed on the first mold 310 so as to overlap with both the first opening 312 and the second opening 314 of the first mold 310 .

[0053] Next, the third module 330 (eg, a stopper) presses the portion of the film 200 around both the first opening 312 and the second opening 314 of the first mold 310 toward the first mold 310. Thus, the film 200 is fixed to the first mold 310.

[0054] Next, the first module 322 and the second module 324 of the second mold 320 are moved from the upper side (positive direction of the sixth direction R) to the lower side (negative direction of the sixth direction R) and enter the first opening 312 and the second opening 314 of the first mold 310, respectively. At this time, the first module 322 is moved until the lower surface (the surface on the negative direction side of the sixth direction R) of the first module 322 reaches a position lower than the upper end (the end on the positive direction side of the sixth direction R) of the protrusion 316 (the end on the positive direction side of the sixth direction R). Similarly, the second module 324 is moved until the lower surface (the surface on the negative direction side of the sixth direction R) of the second module 324 reaches a position lower than the upper end (the end on the positive direction side of the sixth direction R) of the protrusion 316 (the end on the positive direction side of the sixth direction R). Thus, the first receiving portion 210 and the second receiving portion 220 are formed on the film 200 in the region overlapping with the first module 322 and the second module 324 in the sixth direction R, respectively. In addition, between the first module 322 and the second module 324, the film 200 is stretched along the bend of the front end (upper end) of the protrusion 316 (the end on the positive direction side of the sixth direction R), and the recessed portion 232 is formed in the film 200. In addition, while the film 200 is stretched along the bend of the front end (upper end) of the protrusion 316 (the end on the positive direction side of the sixth direction R), the film 200 is not pressed by a pressing member such as a stopper from the opposite side of the protrusion 316 (the upper side of the protrusion 316, that is, the positive direction side of the protrusion 316 in the sixth direction R).

[0055] Assuming that the front end (upper end) of the protrusion 316 is not bent but has an angle (for example, the upper surface of the protrusion 316 is a flat surface parallel to the fifth direction Q, and an angle is formed between the flat surface of the protrusion 316 and the side surfaces on both sides of the fifth direction Q of the protrusion 316, or the front end (upper end) of the protrusion 316 protrudes in a triangular shape), the force may be locally concentrated on the portion of the film 200 that contacts the angle of the protrusion 316. In this case, the thickness of this portion of the film 200 may be locally thinned. Therefore, the fracture resistance of this portion of the film 200 may be locally deteriorated. In contrast, in the present embodiment, substantially the same force is applied to the film 200 along the bend of the front end (upper end) of the protrusion 316 (the end on the positive direction side of the sixth direction R). Therefore, it is possible to suppress the reduction of the fracture resistance of the portion of the film 200 where the recess 232 is provided.

[0056] Assuming that the film 200 is pressed by a pressing member such as a stopper from the opposite side of the protrusion 316 (the upper side of the protrusion 316, i.e., the positive side of the sixth direction R of the protrusion 316) while the film 200 is stretched along the bending of the front end (upper end) of the protrusion 316 (the end on the positive side of the sixth direction R), the thickness of the portion of the film 200 that contacts both the protrusion 316 and the pressing member may be locally thinned. Therefore, the fracture resistance of this portion of the film 200 may be locally deteriorated. In contrast, in the present embodiment, the film 200 is not pressed by a pressing member such as a stopper from the opposite side of the protrusion 316 (the upper side of the protrusion 316, i.e., the positive side of the sixth direction R of the protrusion 316) while the film 200 is stretched along the bending of the front end (upper end) of the protrusion 316 (the end on the positive side of the sixth direction R). Therefore, it is possible to suppress the reduction of the fracture resistance of the portion of the film 200 where the recess 232 is provided.

[0057] When viewed from the fourth direction P, the front end (upper end) of the protrusion 316 (the end on the positive direction side of the sixth direction R) may be curved, for example, into an arc shape. In this case, the diameter of the arc may be substantially equal to the width of the protrusion 316 in the fifth direction Q, for example, it may be greater than 90% and less than 110% of the width of the protrusion 316 in the fifth direction Q. Alternatively, when viewed from the fourth direction P, the front end (upper end) of the protrusion 316 (the end on the positive direction side of the sixth direction R) may be curved into a parabola shape.

[0058] The first module 322 has a first curved surface 322a. The first curved surface 322a of the first module 322 is curved from one of the surface of the first module 322 (the lower surface of the first module 322, i.e., the surface on the negative direction side of the sixth direction R) facing (contacting) the film 200 and the surface of the first module 322 (the side surface of the first module 322, i.e., the surface on the negative direction side of the fifth direction Q) facing the second module 324 toward the other. Therefore, compared with the case where the angle between the above-mentioned lower surface (the surface on the negative direction side of the sixth direction R) and the above-mentioned side surface (the surface on the negative direction side of the fifth direction Q) of the first module 322 is, for example, a right angle, it is possible to apply a force to the film 200 in the same manner along the curve between the above-mentioned lower surface (the surface on the negative direction side of the sixth direction R) and the above-mentioned side surface (the surface on the negative direction side of the fifth direction Q) of the first module 322. Therefore, it is possible to suppress reduction in fracture resistance of the portion of the film 200 that is in curved contact with the lower surface (the surface on the negative side of the sixth direction R) and the side surface (the surface on the negative side of the fifth direction Q) of the first module 322.

[0059] The second module 324 has a second curved surface 324a. The second curved surface 324a of the second module 324 is curved from one of the surface of the second module 324 (the lower surface of the second module 324, i.e., the surface on the negative direction side of the sixth direction R) facing the film 200 and the surface of the second module 324 (the side surface of the second module 324, i.e., the surface on the positive direction side of the fifth direction Q) facing the first module 322 toward the other. Therefore, compared with the case where the angle between the above-mentioned lower surface (the surface on the negative direction side of the sixth direction R) and the above-mentioned side surface (the surface on the positive direction side of the fifth direction Q) of the second module 324 is, for example, a right angle, it is possible to apply the same force to the film 200 along the curve between the above-mentioned lower surface (the surface on the negative direction side of the sixth direction R) and the above-mentioned side surface (the surface on the positive direction side of the fifth direction Q) of the second module 324. Therefore, it is possible to suppress reduction in fracture resistance of the portion of the film 200 that is in curved contact with the lower surface (the surface on the negative direction side of the sixth direction R) and the side surface (the surface on the positive direction side of the fifth direction Q) of the second module 324.

[0060] In the present embodiment, both the first curved surface 322a and the second curved surface 324a are provided. However, only one of the first curved surface 322a and the second curved surface 324a may be provided. Alternatively, the first curved surface 322a and the second curved surface 324a may not be provided.

[0061] In the present embodiment, during the formation of the first receiving portion 210 on the film 200, the film 200 is not pressed from the opposite side of the first module 322 (the lower side of the first module 322, i.e., the negative side of the sixth direction R of the first module 322). That is, during the formation of the first receiving portion 210 on the film 200, the film 200 does not contact the surface of the first mold 310 that is opposite to the first module 322. However, when the film 200 forms the first receiving portion 210, the film 200 may be pressed from the opposite side of the first module 322 (the lower side of the first module 322, i.e., the negative side of the sixth direction R of the first module 322). For example, when the first receiving portion 210 is formed on the film 200, the film 200 may contact the surface of the first mold 310 that is opposite to the first module 322. The same is true for the formation of the second receiving portion 220.

[0062] The manufacturing method (processing method) of the film 200 is not limited to using Figures 5 to 7For example, the first mold 310 may be arranged above the film 200, the second mold 320 may be arranged below the film 200, and the first module 322 and the second module 324 may be pressed toward the first mold 310 from the bottom of the film 200 toward the top, thereby forming the first receiving portion 210 and the second receiving portion 220. Alternatively, the first mold 310 may be moved relative to the second mold 320 (the first module 322 and the second module 324) without moving the second mold 320 (the first module 322 and the second module 324) relative to the first mold 310, thereby forming the first receiving portion 210 and the second receiving portion 220.

[0063] Figure 8 It is used to illustrate the use of Figures 5 to 7 The diagram is a diagram showing an example of a method of wrapping a battery element 100 with a film 200 manufactured (processed) by an apparatus 300 (ie, a method of manufacturing the battery 10 ).

[0064] Figure 8 The second direction Y and the third direction Z in Figures 1 to 4 The second direction Y and the third direction Z are the same.

[0065] like Figure 8 As shown, the film 200 is folded back from one of the first receiving portion 210 and the second receiving portion 220 to the other. Thus, the first receiving portion 210 of the film 200 covers one side of the battery element 100 (the positive direction side of the third direction Z), and the second receiving portion 220 of the film 200 covers the other side of the battery element 100 (the negative direction side of the third direction Z). At this time, by using Figures 5 to 7 The recessed portion 232 formed by the above-described method remains on the right side of the battery element 100 (the positive direction side in the second direction Y). Next, a portion of the film 200 and another portion of the film 200 overlapping in the third direction Z are bonded to each other, for example, by welding, except for a portion overlapping with the first lead 112 or the second lead 122 in a region surrounding the battery element 100 as viewed from the third direction Z. In this way, the battery 10 is manufactured.

[0066] Example

[0067] (Example)

[0068] By using Figures 5 to 7 The described method processes the thin film 200. The conditions of the thin film 200 are as follows.

[0069] Length in the fourth direction P: 30cm

[0070] Width in the fifth direction Q: 40cm

[0071] Thickness in the sixth direction R: 0.15 mm

[0072] Material: Aluminum Laminated Film

[0073] In addition, the conditions of the apparatus 300 are as follows.

[0074] Length of each of the first opening 312 and the second opening 314 in the fourth direction P: 25 cm

[0075] Width of each of the first opening 312 and the second opening 314 in the fifth direction Q: 10 cm

[0076] Width of the protrusion 316 in the fifth direction Q: 0.4 cm

[0077] Curvature of the front end (upper end) of the protrusion 316: arc with a curvature radius of 0.2 cm

[0078] Length of each of the first module 322 and the second module 324 in the fourth direction P: 24.8 cm

[0079] Width of each of the first module 322 and the second module 324 in the fifth direction Q: 9.8 cm

[0080] (Comparative Example)

[0081] Fig. 9 is a diagram for explaining a method for manufacturing (processing) a thin film 200 of a comparative example, and Figure 7 correspond. Fig. 9 The fifth direction Q and the sixth direction R in Figures 5 to 7 The comparative example is the same as the embodiment except that the film 200 is pressed by the stopper 400 from the opposite side of the protrusion 316 (the upper side of the protrusion 316, that is, the positive direction side of the sixth direction R of the protrusion 316) while the film 200 is stretched along the bending of the front end (upper end) of the protrusion 316 (the end on the positive direction side of the sixth direction R).

[0082] Fig.10 It is a diagram for explaining the position at which the thickness of the thin film 200 is measured. Fig.10 The fourth direction P and the fifth direction Q in Figures 5 to 7 The fourth direction P and the fifth direction Q are the same.

[0083] In the thin films 200 produced (processed) in the examples and comparative examples, the Fig.10Thickness of the six positions from position 1 to position 6 indicated by the black circles (thickness in the sixth direction R). Positions 1 to 6 are located at the center of the area between the first receiving portion 210 and the second receiving portion 220 in the fifth direction Q (i.e., the center of the area where the recess 232 is formed in the fifth direction Q). Position 1 is offset from the edge of the first receiving portion 210 and the second receiving portion 220 on the negative direction side of the fourth direction P by a distance d (2 cm) toward the positive direction of the fourth direction P. Positions 1 to 6 are arranged in this order from the negative direction of the fourth direction P to the positive direction at equal intervals of g (1 cm).

[0084] Table 1 shows the positions 1 to 6 of the thin film 200 manufactured (processed) in the embodiment and the comparative example. Fig.10 ) is a summary of the measurement results of the respective thicknesses at .

[0085] In Table 1, the column "R (%)" in the row "Example" indicates the position 1 to position 6 ( Fig.10 ) at each position of the film 200 after processing to the thickness of the film 200 before processing. The column of "Standard Deviation" in the row of "Example" represents the standard deviation of the ratio R at positions 1 to 6 in the example. The column of "Average" in the row of "Example" represents the average of the ratio R at positions 1 to 6 in the example. The column of "Standard Deviation / Average" in the row of "Example" represents the ratio of the standard deviation of the ratio R at positions 1 to 6 in the example to the average (coefficient of variation).

[0086] In Table 1, the column "R (%)" in the row "Comparative Example" indicates the positions 1 to 6 ( Fig.10 ) at each position of the film 200 after processing to the thickness of the film 200 before processing. It should be noted that at position 1 of the comparative example, the film 200 was broken and the ratio R could not be measured. The column of "Standard Deviation" in the row of "Comparative Example" represents the standard deviation of the ratio R from position 2 to position 6 in the comparative example. The column of "Average" in the row of "Comparative Example" represents the average of the ratio R from position 2 to position 6 in the comparative example. The column of "Standard Deviation / Average" in the row of "Comparative Example" represents the ratio (coefficient of variation) of the standard deviation in the comparative example to the average of the ratio R from position 2 to position 6.

[0087] [Table 1]

[0088]

[0089] According to the respective results of the embodiment and the comparative example in Table 1, while the film 200 is stretched along the bending of the front end (upper end) of the protrusion 316 (the end on the positive direction side of the sixth direction R), when the film 200 is not pressed by the stopper 400 from the opposite side of the protrusion 316 (the upper side of the protrusion 316, i.e., the positive direction side of the sixth direction R of the protrusion 316), it can be said that the film 200 can have high fracture resistance.

[0090] When the film 200 surrounds the battery element 100, when viewed from the right side of the battery 10 (the positive direction side in the second direction Y), Fig.10 The positions 1 to 6 shown are located approximately in the range from the end of the battery element 100 in the first direction X to 1 / 4 of the total length of the battery element 100 in the first direction X. Therefore, in the present embodiment, it can be said that the ratio of the standard deviation of the thickness of the portion where the recess 232 is provided in the film 200 to the average value in the range from the end of the battery element 100 in the first direction X to 1 / 4 of the total length of the battery element 100 in the first direction X is 0.0500 or less, for example, 0.0250 or less or 0.0100 or less.

[0091] As mentioned above, although embodiment and Example of this invention were described with reference to drawings, these are illustrations of this invention, and various structures other than the above-mentioned can also be adopted.

[0092] This application claims the benefit of priority based on Japanese patent application No. 2019-218916, filed on December 3, 2019, the entire disclosure of which is incorporated herein by reference.

Claims

1. A battery comprising a battery element and a thin film, The battery element comprises a positive electrode, a negative electrode and a separator. The film has a first housing portion covering one side of the battery element and a second housing portion covering the other side of the battery element opposite to the first side. A recess is provided in the film at a portion folded back from one of the first receiving portion and the second receiving portion toward the other, the recess being recessed toward the battery element and extending in a direction orthogonal to a direction from the one side toward the other side in the battery element, The depth of the recessed portion becomes shallower as it moves away from the center of the battery element in the one direction.

2. The battery according to claim 1, wherein The recessed portion is bent in a convex shape toward the battery element.

3. The battery according to claim 1 or 2, wherein: In a range from an end of the battery element in the one direction to 1 / 4 of the entire length of the battery element in the one direction, a ratio of a standard deviation of the thickness of a portion of the film where the recess is provided to an average value is 0.0500 or less.

4. A battery comprising a battery element and a thin film, The battery element comprises a positive electrode, a negative electrode and a separator. The film has a first housing portion covering one side of the battery element and a second housing portion covering the other side of the battery element opposite to the first side. A recess is provided in the film at a portion folded back from one of the first receiving portion and the second receiving portion toward the other, the recess being recessed toward the battery element and extending in a direction orthogonal to a direction from the one side toward the other side in the battery element, At least a portion of the recess is located at a portion of the portion of the thin film that overlaps with the center of the battery element in the one direction.

5. The battery according to claim 4, wherein The recessed portion is bent in a convex shape toward the battery element.

6. The battery according to claim 4 or 5, wherein: In a range from an end of the battery element in the one direction to 1 / 4 of the entire length of the battery element in the one direction, a ratio of a standard deviation of the thickness of a portion of the film where the recess is provided to an average value is 0.0500 or less.

7. The battery according to claim 4 or 5, wherein: The depth of the recessed portion becomes shallower as it moves away from the center of the battery element in the one direction.

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