Battery cell and method for manufacturing battery cell

Abstract

To improve sealing performance around a terminal.SOLUTION: The battery cell 100 includes a battery element 110, an exterior material 120 at least partially sealed around the battery element 110, and a first terminal 130 electrically connected to the battery element 110, at least partially led out from between parts of the exterior material 120, and covered with a first sealing material 150 between the parts of the exterior material 120. The first terminal 130 has a first inclined surface 134 that is inclined from the side where one of the portions of the exterior material 120 is located toward the side where the other of the portions of the exterior material 120 is located. The first inclined surface 134 and the part of the exterior material 120 are at least partially disposed substantially parallel to each other.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a battery cell and a method for manufacturing the battery cell. [Background technology]

[0002] In recent years, various types of battery cells have been developed. A battery cell may include a battery element, an exterior material, and terminals. In a battery cell, portions of the exterior material may be sealed around the battery element with the terminals extending from between the portions of the exterior material.

[0003] Patent Document 1 describes a laminated Li-ion secondary battery. This battery includes a tab lead. The tab lead includes a metal strip and a resin tape covering both sides of the metal strip. At least one end of the side of the metal strip is chamfered.

[0004] Patent Document 2 describes a method for manufacturing a film-covered battery. In this method, a heater heat-seals exterior film layers to each other around an electrical device element, and heat-seals the sealant and exterior film. The heater has a peripheral heating section that heat-seals the exterior film layers to each other, a terminal heating section that is concave relative to the peripheral heating section and heat-seals the sealant and exterior film, and an intermediate heating section that connects the peripheral heating section and the terminal heating section in a stepped manner.

[0005] Patent Document 3 describes a method for manufacturing a nonaqueous electrolyte battery, in which a terminal leading edge of a laminate film is heat-sealed by a first heater block having a notch wider than the width of the sealant, and the terminal leading edge of the laminate film is heat-sealed by a second heater block having a notch narrower than the width of the sealant, thereby forming a first step portion and a second step portion on the terminal leading edge of the laminate film.

[0006] Patent Document 4 describes an energy storage element. The energy storage element includes lead terminals and exterior films partially positioned on both sides of the lead terminals in the thickness direction. The lead terminals include a terminal body, resin layers partially positioned on both sides of the terminal body in the thickness direction, and intermediate layers positioned on both sides of the terminal body in the width direction.

[0007] Patent Document 5 describes a method for manufacturing a lithium-ion battery, in which lead electrodes are placed between sealing materials, the sealing materials are placed between exterior packaging materials, and a release sheet is placed between the exterior packaging materials and the heater, and the heater is pressed against the exterior packaging materials. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-243015 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-242548 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-244725 [Patent Document 4] Japanese Patent Application Laid-Open No. 2016-162744 [Patent Document 5] Japanese Patent Application Laid-Open No. 2001-266952 Summary of the Invention [Problem to be solved by the invention]

[0009] In a battery cell, terminals electrically connected to battery elements may be pulled out from the exterior packaging material. When the terminals are pulled out from the exterior packaging material, it may be necessary to improve the sealing performance around the terminals.

[0010] One object of the present invention is to improve the sealing performance around the terminal. Other objects of the present invention will become apparent from the description of this specification. [Means for solving the problem]

[0011] One aspect of the present invention is as follows. 1. A battery element; an exterior material at least partially sealed around the battery element; a terminal electrically connected to the battery element, at least partially drawn out from between the portions of the exterior material, and covered with a sealing material between the portions of the exterior material; Equipped with the terminal has an inclined surface that is inclined from a side where one of the portions of the exterior material is located toward a side where the other of the portions of the exterior material is located, The battery cell, wherein the inclined surface and the portion of the exterior material are at least partially arranged substantially parallel. 2. A battery cell as described in 1., wherein the inclined surface is located on both the side where one of the portions of the exterior material is located and the side where the other of the portions of the exterior material is located. 3. A process for at least partially sealing an exterior material around a battery element, wherein a terminal electrically connected to the battery element is at least partially drawn out from between portions of the exterior material, the terminal is covered by a sealing material between the portions of the exterior material, and the terminal has an inclined surface that slopes from a side where one of the portions of the exterior material is located to a side where the other of the portions of the exterior material is located; a step of sealing the exterior material, the step of pressing a heating surface of a heating body toward at least one of the portions of the exterior material while the inclined surface and the heating surface are at least partially arranged approximately parallel to each other. 4. The method for manufacturing a battery cell described in 3., wherein the heating surface has a first region that is pressed toward at least one of the portions of the exterior material between which the sealing material is located, a second region that is pressed toward at least one of the portions of the exterior material between which the sealing material is not located, and a third region that is located between the first region and the second region and is recessed relative to the second region. [Effects of the Invention]

[0012] According to the above aspect of the present invention, the sealing performance around the terminal can be improved. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 2 is a side view of a battery cell according to the embodiment. [Figure 2] FIG. 2 is a perspective view of a battery cell according to an embodiment with the exterior material removed. [Figure 3] FIG. 2 is a cross-sectional view taken along the line AA in FIG. [Figure 4] 5A to 5C are diagrams for explaining a method for manufacturing a battery cell according to an embodiment. [Figure 5] 10A to 10C are diagrams for explaining a manufacturing method of a battery cell according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, similar components are designated by similar reference numerals, and the description thereof will be omitted as appropriate.

[0015] Fig. 1 is a side view of a battery cell 100 according to an embodiment. Fig. 2 is a perspective view of the battery cell 100 according to an embodiment with the exterior material 120 removed. Fig. 3 is a cross-sectional view taken along line AA in Fig. 1.

[0016] For the purpose of explanation, each figure shows an X axis, a Y axis, and a Z axis, which respectively indicate the X direction, the Y direction, and the Z direction. The X direction is a direction parallel to the length direction of the battery cell 100. The Y direction is one of the directions perpendicular to the X direction. The Y direction is a direction parallel to the thickness direction of the battery cell 100. The Z direction is a direction perpendicular to both the X direction and the Y direction. The Z direction is a direction parallel to the width direction of the battery cell 100. In FIG. 1, a white circle with a black dot indicating the Y direction indicates that the tip of the arrow indicating the Y axis is facing outward from the paper. In FIG. 3, a white circle with a black dot indicating the X direction indicates that the tip of the arrow indicating the X axis is facing outward from the paper.

[0017] Hereinafter, unless otherwise specified, the +X side refers to the side indicated by the tip of the arrow indicating the X axis, and the -X side refers to the side opposite the side indicated by the tip of the arrow indicating the X axis. Hereinafter, unless otherwise specified, the +Y side refers to the side indicated by the tip of the arrow indicating the Y axis, and the -Y side refers to the side opposite the side indicated by the tip of the arrow indicating the Y axis. Hereinafter, unless otherwise specified, the +Z side refers to the side indicated by the tip of the arrow indicating the Z axis, and the -Z side refers to the side opposite the side indicated by the tip of the arrow indicating the Z axis.

[0018] As shown in FIGS. 1 to 3, a battery cell 100 according to the embodiment includes a battery element 110, an exterior material 120, a first terminal 130, a second terminal 140, a first sealing material 150, and a second sealing material 160.

[0019] As shown in FIG. 2, the battery element 110 has a substantially rectangular parallelepiped shape with a height substantially parallel to the Y direction and a substantially rectangular bottom surface having a pair of long sides substantially parallel to the X direction and a pair of short sides substantially parallel to the Z direction. The shape of the battery element 110 is not limited to the example shown in FIG. 2. As shown in FIG. 2, in the embodiment, the battery element 110 has a plurality of positive electrodes 112, a plurality of negative electrodes 114, and a plurality of separators 116. In the embodiment, the plurality of positive electrodes 112 and the plurality of negative electrodes 114 are alternately arranged in the Y direction, with adjacent positive electrodes 112 and negative electrodes 114 separated from each other by the separators 116. The structure of the battery element 110 is not limited to this example. For example, the separator 116 may be formed in a substantially Z-folded shape, with one portion of the separator 116 covering one of the +Y side end and the −Y side end of each positive electrode 112, another portion of the separator 116 covering the other of the +Y side end and the −Y side end of each negative electrode 114, and another portion of the separator 116 between that portion and that other portion separating adjacent positive electrodes 112 and negative electrodes 114 from each other.

[0020] The exterior material 120 is, for example, a laminate film having a metal layer such as aluminum foil and resin films located on both sides of the metal layer. As shown in Figures 1 and 3, the exterior material 120 has a first exterior film 122 that covers the +Y side surface of the battery element 110 and a second exterior film 124 that covers the -Y side surface of the battery element 110. The exterior material 120 according to the embodiment is a single film that is folded from one side of the first exterior film 122 and the second exterior film 124 to the other on the -Z side of the battery element 110.

[0021] In the embodiment, overlapping portions of the first exterior film 122 and the second exterior film 124 in the Y direction are sealed around the battery element 110. Specifically, as shown in Fig. 1, portions of the first exterior film 122 and the second exterior film 124 located on the +X side with respect to the battery element 110 are sealed together to form a first sealed portion 120a. Portions of the first exterior film 122 and the second exterior film 124 located on the -X side with respect to the battery element 110 are sealed together to form a second sealed portion 120b. Portions of the first exterior film 122 and the second exterior film 124 located on the +Z side with respect to the battery element 110 are sealed together to form a third sealed portion 120c.

[0022] As shown in Fig. 3, in a region of the first sealed portion 120a where the first sealing material 150 is not located between the first exterior film 122 and the second exterior film 124, the first exterior film 122 and the second exterior film 124 are joined to each other by bonding such as heat fusion. As shown in Fig. 3, in a region of the first sealed portion 120a where the first sealing material 150 is located between the first exterior film 122 and the second exterior film 124, the -Y side surface of the first exterior film 122 and the +Y side surface of the first sealing material 150 are joined to each other by bonding such as heat fusion, and the +Y side surface of the second exterior film 124 and the -Y side surface of the first sealing material 150 are joined to each other by bonding such as heat fusion.

[0023] 3, in a region of the second sealed portion 120b where the second sealing material 160 is not located between the first exterior film 122 and the second exterior film 124, the first exterior film 122 and the second exterior film 124 are joined to each other by bonding such as heat fusion. Similarly to the example shown in Fig. 3, in a region of the second sealed portion 120b where the second sealing material 160 is located between the first exterior film 122 and the second exterior film 124, the -Y side surface of the first exterior film 122 and the +Y side surface of the second sealing material 160 are joined to each other by bonding such as heat fusion, and the +Y side surface of the second exterior film 124 and the -Y side surface of the second sealing material 160 are joined to each other by bonding such as heat fusion.

[0024] In the third sealed portion 120c, the first exterior film 122 and the second exterior film 124 are joined to each other by bonding such as heat fusion. In the example shown in Fig. 1, the third sealed portion 120c is folded into a predetermined shape.

[0025] The structure of the exterior material 120 is not limited to the example according to the embodiment. For example, two separate exterior materials 120 may cover both sides of the battery element 110 in the Y direction. In this example, the two exterior materials 120 may form a sealing portion along the entire periphery of the battery element 110 in the Y direction.

[0026] The first terminal 130 is made of a metal such as aluminum or an aluminum alloy. As shown in FIG. 2, one end of the first terminal 130 on the −X side and one end of the positive electrode drawn current collector 113 drawn from the positive electrode 112 of the battery element 110 on the +X side are electrically connected to each other via bonding such as ultrasonic bonding. Thus, the first terminal 130 and the positive electrode 112 are electrically connected to each other via the positive electrode drawn current collector 113. As shown in FIGS. 1 and 3, the first terminal 130 is at least partially drawn out from between the first exterior film 122 and the second exterior film 124 in the first sealed portion 120a toward the +X side, with the other end of the first terminal 130 on the +X side protruding from the first sealed portion 120a.

[0027] 2 and 3 , the outer peripheral surface of the first terminal 130 in the X direction is covered by a first sealing material 150 between the first exterior film 122 and the second exterior film 124 in the first sealed portion 120a. The first sealing material 150 contains, for example, a resin. By providing the first sealing material 150 between the outer peripheral surface of the first terminal 130 in the X direction and the inner peripheral surfaces of the first exterior film 122 and the second exterior film 124 around the outer peripheral surface of the first terminal 130, it is possible to improve the sealing between the outer peripheral surface of the first terminal 130 in the X direction and the inner peripheral surfaces of the first exterior film 122 and the second exterior film 124 around the outer peripheral surface of the first terminal 130.

[0028] The second terminal 140 is made of a metal such as copper or a copper alloy. As shown in Fig. 2, one end on the +X side of the second terminal 140 and one end on the -X side of the negative electrode drawn current collector 115 drawn from the negative electrode 114 of the battery element 110 are electrically connected to each other via joining such as ultrasonic welding. Thus, the second terminal 140 and the negative electrode 114 are electrically connected to each other via the negative electrode drawn current collector 115. As shown in Fig. 1, the second terminal 140 is at least partially drawn out from between the first exterior film 122 and the second exterior film 124 in the second sealed portion 120b toward the -X side, with the other end on the -X side of the second terminal 140 protruding from the second sealed portion 120b.

[0029] 2, similar to the outer peripheral surface around the X direction of the first terminal 130, the outer peripheral surface around the X direction of the second terminal 140 is covered by the second sealing material 160 between the first exterior film 122 and the second exterior film 124 in the second sealed portion 120b. By providing the second sealing material 160 between the outer peripheral surface around the X direction of the second terminal 140 and the inner peripheral surfaces of the first exterior film 122 and the second exterior film 124 around the outer peripheral surface of the second terminal 140, it is possible to improve the sealing performance between the outer peripheral surface around the X direction of the second terminal 140 and the inner peripheral surfaces of the first exterior film 122 and the second exterior film 124 around the outer peripheral surface of the second terminal 140.

[0030] The arrangement of the first terminal 130 and the second terminal 140 is not limited to the example according to the embodiment. For example, both the first terminal 130 and the second terminal 140 may be drawn out from the +X side or the −X side.

[0031] The +Z side portion of the first sealing portion 120a will be described with reference to Fig. 3. The matters described with reference to Fig. 3 are also applicable to the -Z side portion of the first sealing portion 120a and the second sealing portion 120b.

[0032] As shown in FIG. 3, the first terminal 130 includes a first flat surface 132, a first inclined surface 134, a second flat surface 136, and a second inclined surface 138. The first flat surface 132, the first inclined surface 134, the second flat surface 136, and the second inclined surface 138 are covered by a first sealing material 150 between the first exterior film 122 and the second exterior film 124. The first flat surface 132 and the second flat surface 136 are arranged approximately symmetrically. The first inclined surface 134 and the second inclined surface 138 are arranged approximately symmetrically. As shown in FIG. 3, the first exterior film 122 includes a first flat portion 122a, a first inclined portion 122b, a second flat portion 122c, and a third flat portion 122d. As shown in FIG. 3, the second exterior film 124 includes a fourth flat portion 124a, a second inclined portion 124b, a fifth flat portion 124c, and a sixth flat portion 124d. The first flat portion 122a and the fourth flat portion 124a are arranged approximately symmetrically. The first inclined portion 122b and the second inclined portion 124b are arranged approximately symmetrically. The second flat portion 122c and the fifth flat portion 124c are arranged approximately symmetrically. The third flat portion 122d and the sixth flat portion 124d are arranged approximately symmetrically.

[0033] The first flat surface 132 and the second flat surface 136 are disposed approximately perpendicular to the Y direction. The first flat surface 132 and the second flat surface 136 are located on the +Y side and the -Y side, respectively. The thickness of the first terminal 130 in the Y direction between the first flat surface 132 and the second flat surface 136 is approximately constant over approximately the entire area between the first flat surface 132 and the second flat surface 136.

[0034] As shown in FIG. 3 , the first inclined surface 134 and the second inclined surface 138 are located on the +Z side relative to the first flat surface 132 and the second flat surface 136, respectively. In other words, the first flat surface 132 and the second flat surface 136 are located in the center of the first terminal 130 in the Z direction relative to the first inclined surface 134 and the second inclined surface 138, respectively. As shown in FIG. 3 , the first inclined surface 134 and the second inclined surface 138 are located on the +Y side and the -Y side, respectively. As shown in FIG. 3 , the first inclined surface 134 is inclined from the first flat surface 132 toward the -Y side. That is, the first inclined surface 134 is inclined from the side where the first exterior film 122 is located toward the side where the second exterior film 124 is located. As shown in FIG. 3 , the second inclined surface 138 is inclined from the second flat surface 136 toward the +Y side. That is, the second inclined surface 138 is inclined from the side where the second exterior film 124 is located toward the side where the first exterior film 122 is located. Therefore, the end portion of the first terminal 130 between the first inclined surface 134 and the second inclined surface 138 has a tapered shape. That is, the thickness in the Y direction of the end portion of the first terminal 130 between the first inclined surface 134 and the second inclined surface 138 decreases with increasing distance from the first flat surface 132 and the second flat surface 136.

[0035] When the first inclined surface 134 and the second inclined surface 138 are provided, it is easier to fill the first sealing material 150 without gaps around the +Z side end of the first terminal 130 compared to when the first inclined surface 134 and the second inclined surface 138 are not provided and both Y-direction surfaces of the first terminal 130 are simply flat surfaces. In particular, as the Y-direction thickness of the first terminal 130 increases, it may become more difficult to fill the periphery of the +Z side end of the first terminal 130 with the first sealing material 150 without gaps when both Y-direction surfaces of the first terminal 130 are simply flat surfaces. However, in the embodiment, even when the Y-direction thickness of the first terminal 130 is relatively thick, it is easier to fill the periphery of the +Z side end of the first terminal 130 with the first sealing material 150 without gaps. The Y-direction thickness of the first terminal 130, i.e., the Y-direction thickness of the first flat surface 132 and the second flat surface 136, is, for example, 0.1 mm or more and 1.0 mm or less.

[0036] 3, the first flat portion 122a and the first flat surface 132 are at least partially disposed substantially parallel to each other. Therefore, the portion of the first sealing material 150 located between the first flat portion 122a and the first flat surface 132 has a substantially uniform thickness over substantially the entire area between the first flat portion 122a and the first flat surface 132. This improves the sealing performance around the first terminal 130 compared to a case where the thickness of the first sealing material 150 varies depending on the position between the first flat portion 122a and the first flat surface 132. The same applies to the fourth flat portion 124a and the second flat surface 136 and the portion of the first sealing material 150 located between the fourth flat portion 124a and the second flat surface 136.

[0037] 3, the first inclined portion 122b and the first inclined surface 134 are at least partially disposed substantially parallel to each other. Therefore, the portion of the first sealing material 150 located between the first inclined portion 122b and the first inclined surface 134 has a substantially uniform thickness over substantially the entire area between the first inclined portion 122b and the first inclined surface 134. This improves the sealing performance around the first terminal 130 compared to a case where the thickness of the first sealing material 150 varies depending on the position between the first inclined portion 122b and the first inclined surface 134. The same is true for the second inclined portion 124b and the second inclined surface 138 and the portion of the first sealing material 150 located between the second inclined portion 124b and the second inclined surface 138.

[0038] The second flat portion 122c and the fifth flat portion 124c are located on the +Z side with respect to the first inclined portion 122b and the second inclined portion 124b, respectively. The second flat portion 122c and the fifth flat portion 124c are disposed substantially perpendicular to the Y direction. A portion of the first sealing material 150 is located between the second flat portion 122c and the fifth flat portion 124c.

[0039] The third flat portion 122d and the sixth flat portion 124d are located on the +Z side relative to the second flat portion 122c and the fifth flat portion 124c, respectively. The third flat portion 122d and the sixth flat portion 124d are arranged approximately perpendicular to the Y direction. The first sealing material 150 is not located between the third flat portion 122d and the sixth flat portion 124d. The third flat portion 122d and the sixth flat portion 124d are joined to each other via joining such as heat fusion.

[0040] The shape of first terminal 130 is not limited to the example shown in Fig. 3. For example, one of the +Y side surface and the -Y side surface of first terminal 130 does not have to have an inclined surface at the end on the +Z side of first terminal 130. In other words, one of the +Y side surface and the -Y side surface of first terminal 130 may be flat over the entirety.

[0041] Fig. 4 is a diagram for explaining a method for manufacturing the battery cell 100 according to the embodiment. Fig. 5 is a diagram for explaining a method for manufacturing the battery cell 100 according to the comparative example. The battery cell 100 according to the embodiment is manufactured as follows.

[0042] First, battery element 110 is formed. Next, with first sealing material 150 at least partially covering the outer peripheral surface of first terminal 130, one end on the -X side of first terminal 130 and one end on the +X side of positive electrode drawn current collector 113 are electrically connected to each other via joining such as ultrasonic welding. Similarly, with second sealing material 160 at least partially covering the outer peripheral surface of second terminal 140, one end on the +X side of second terminal 140 and one end on the -X side of negative electrode drawn current collector 115 are electrically connected to each other via joining such as ultrasonic welding.

[0043] Next, the battery element 110 is wrapped in the exterior material 120. With the exterior material 120 wrapping the battery element 110, the first exterior film 122 covers the +Y side surface of the battery element 110, and the second exterior film 124 covers the -Y side surface of the battery element 110. With the exterior material 120 wrapping the battery element 110, the first sealing material 150 is located between the +X side end of the first exterior film 122 and the +X side end of the second exterior film 124, and the second sealing material 160 is located between the -X side end of the first exterior film 122 and the -X side end of the second exterior film 124. When the exterior material 120 encases the battery element 110, the first terminal 130 is at least partially pulled out from between the +X side end of the first exterior film 122 and the +X side end of the second exterior film 124, and the second terminal 140 is at least partially pulled out from between the -X side end of the first exterior film 122 and the -X side end of the second exterior film 124.

[0044] Next, with the first seal bar 210 heated to a predetermined temperature, the first seal bar 210 is pressed against the +Y side surface of the first exterior film 122 surrounding the battery element 110 in the Y direction, and with the second seal bar 220 heated to a predetermined temperature, the second seal bar 220 is pressed against the -Y side surface of the second exterior film 124 surrounding the battery element 110 in the Y direction. The first seal bar 210 and the second seal bar 220 can seal the overlapping portions of the first exterior film 122 and the second exterior film 124 in the Y direction around the battery element 110. In other words, the first seal bar 210 and the second seal bar 220 serve as heating bodies for sealing the portions of the first exterior film 122 and the second exterior film 124 around the battery element 110. The first sealing bar 210 and the second sealing bar 220 seal the overlapping portions of the first exterior film 122 and the second exterior film 124 in the Y direction, thereby forming the first sealed portion 120a, the second sealed portion 120b, and the third sealed portion 120c.

[0045] A method for forming the +Z side portion of the first sealing portion 120a using the first sealing bar 210 and the second sealing bar 220 according to the embodiment will be described with reference to Fig. 4. The matters described with reference to Fig. 3 are also applicable to the -Z side portion of the first sealing portion 120a and the second sealing portion 120b.

[0046] As shown in Fig. 4, the first seal bar 210 according to the embodiment has a first flat heated surface 212, a first inclined heated surface 214, a second flat heated surface 216, and a first concave surface 218. As shown in Fig. 4, the second seal bar 220 according to the embodiment has a third flat heated surface 222, a second inclined heated surface 224, a fourth flat heated surface 226, and a second concave surface 228. The first flat heated surface 212 and the third flat heated surface 222 are arranged substantially symmetrically. The first inclined heated surface 214 and the second inclined heated surface 224 are arranged substantially symmetrically. The second flat heated surface 216 and the fourth flat heated surface 226 are arranged substantially symmetrically. The first concave surface 218 and the second concave surface 228 are arranged substantially symmetrically.

[0047] 4, the first flat heating surface 212 is pressed toward the first flat portion 122a while the first flat surface 132 and the first flat heating surface 212 are at least partially substantially parallel. The first inclined surface 134 and the first inclined heating surface 214 are at least partially substantially parallel, while the first inclined heating surface 214 is pressed toward the first inclined portion 122b. The second flat heating surface 216 is pressed toward the third flat portion 122d while the first sealing material 150 is not located between the third flat portion 122d and the sixth flat portion 124d. The first concave surface 218 is located between the first inclined heating surface 214 and the second flat heating surface 216 and is concave toward the +Y side with respect to the second flat heating surface 216.

[0048] 4, with the second flat surface 136 and the third flat heating surface 222 at least partially substantially parallel, the third flat heating surface 222 is pressed toward the fourth flat portion 124a. With the second inclined surface 138 and the second inclined heating surface 224 at least partially substantially parallel, the second inclined heating surface 224 is pressed toward the second inclined portion 124b. With the first sealing material 150 not positioned between the third flat portion 122d and the sixth flat portion 124d, the sixth flat portion 124d is pressed toward the sixth flat portion 124d. The second concave surface 228 is positioned between the second inclined heating surface 224 and the fourth flat heating surface 226 and is concave toward the -Y side with respect to the fourth flat heating surface 226.

[0049] In the example shown in FIG. 4, when the first seal bar 210 and the second seal bar 220 are pressed toward the first exterior film 122 and the second exterior film 124, respectively, the fluidity of the resin constituting the first sealing material 150 increases due to heat conducted from the first seal bar 210 and the second seal bar 220 to the first sealing material 150. When the fluidity of the resin constituting the first sealing material 150 increases, the resin is extruded toward the outside of the region surrounded by the first exterior film 122 and the second exterior film 124 in the X direction. Furthermore, the resin constituting the exterior material 120 is extruded toward the first sealing material 150 from the region between the first exterior film 122 and the second exterior film 124 around the first sealing material 150. In the example shown in FIG. 3, the region between the first exterior film 122 and the second exterior film 124 around the first sealing material 150 corresponds to the region between the third flat portion 122d and the sixth flat portion 124d. Therefore, in the embodiment, the gap between the area where the outer casing material 120 and the first sealing material 150 are joined to each other and the area where parts of the outer casing material 120 are joined to each other can be filled with the above-mentioned resin, thereby improving the sealing property around the first terminal 130.

[0050] A first seal bar 210Z and a second seal bar 220Z according to a comparative example will be described with reference to Fig. 5. The first seal bar 210Z and the second seal bar 220Z according to the comparative example are similar to the first seal bar 210 and the second seal bar 220 according to the embodiment, respectively, except for the following points.

[0051] The first seal bar 210Z according to the comparative example has a first flat heating surface 212Z, a second flat heating surface 216Z, and a first concave surface 218Z. The first flat heating surface 212Z, the second flat heating surface 216Z, and the first concave surface 218Z according to the comparative example correspond to the first flat heating surface 212, the second flat heating surface 216, and the first concave surface 218, respectively, according to the embodiment. The first seal bar 210Z according to the comparative example does not have an inclined heating surface corresponding to the first inclined heating surface 214 according to the embodiment. In the comparative example, a first vertical surface 214Z parallel to the Y direction is formed between the +Z side end of the first flat heating surface 212Z and the -Z side end of the first concave surface 218Z.

[0052] The second seal bar 220Z according to the comparative example has a third flat heating surface 222Z, a fourth flat heating surface 226Z, and a second concave surface 228Z. The third flat heating surface 222Z, the second flat heating surface 216Z, and the second concave surface 228Z according to the comparative example correspond to the third flat heating surface 222, the fourth flat heating surface 226, and the second concave surface 228 according to the embodiment, respectively. The second seal bar 220Z according to the comparative example does not have an inclined heating surface corresponding to the second inclined heating surface 224 according to the embodiment. In the comparative example, a second vertical surface 224Z parallel to the Y direction is formed between the +Z side end of the third flat heating surface 222Z and the -Z side end of the second concave surface 228Z.

[0053] With reference to FIGS. 4 and 5, the sealing of the first exterior film 122 and the second exterior film 124 according to the embodiment will be compared with the sealing of the first exterior film 122 and the second exterior film 124 according to the comparative example.

[0054] 5, the first seal bar 210Z does not have a heated surface parallel to the first inclined surface 134, and the second seal bar 220Z does not have a heated surface parallel to the second inclined surface 138. Therefore, when the first seal bar 210Z and the second seal bar 220Z are pressed toward the first exterior film 122 and the fourth flat portion 124a, respectively, and the fluidity of the first sealing material 150 is increased by heat conducted from the first seal bar 210Z and the second seal bar 220Z to the first sealing material 150, causing the first sealing material 150 to deform, the first inclined portion 122b and the second inclined portion 124b are formed non-parallel to the first inclined surface 134 and the second inclined surface 138, respectively, in accordance with the deformation of the first sealing material 150. Furthermore, in the comparative example, it may be difficult to prevent the first outer film 122 from breaking due to contact with the corner between the first vertical surface 214Z and the first concave surface 218Z of the first seal bar 210Z of the first outer film 122, or the second outer film 124 from breaking due to contact with the corner between the second vertical surface 224Z and the second concave surface 228Z of the second seal bar 220Z of the second outer film 124.

[0055] 4, the first inclined heating surface 214 and the second inclined heating surface 224 are approximately parallel to the first inclined surface 134 and the second inclined surface 138, respectively. Therefore, even if the first seal bar 210 and the second seal bar 220 are pressed toward the first exterior film 122 and the second exterior film 124, respectively, and the fluidity of the first sealing material 150 is increased by heat conducted from the first seal bar 210 and the second seal bar 220 to the first sealing material 150, the first inclined portion 122b and the second inclined portion 124b can be formed approximately parallel to the first inclined surface 134 and the second inclined surface 138, respectively. Therefore, the portion of the first sealing material 150 located between the first inclined portion 122b and the first inclined surface 134 can have a substantially uniform thickness over substantially the entire area between the first inclined portion 122b and the first inclined surface 134, and the portion of the first sealing material 150 located between the second inclined portion 124b and the second inclined surface 138 can have a substantially uniform thickness over substantially the entire area between the second inclined portion 124b and the second inclined surface 138.

[0056] Furthermore, in the embodiment, since the first concave surface 218 is recessed toward the +Y side, the corner between the first inclined heating surface 214 and the first concave surface 218 can be moved away from the +Z side end of the first inclined portion 122b toward the +Y side. This makes it possible to prevent breakage of the first inclined portion 122b due to contact between the corner and the first inclined portion 122b. Similarly, since the second concave surface 228 is recessed toward the -Y side, the corner between the second inclined heating surface 224 and the second concave surface 228 can be moved away from the +Z side end of the second inclined portion 124b toward the -Y side. This makes it possible to prevent breakage of the second inclined portion 124b due to contact between the corner and the second inclined portion 124b.

[0057] Furthermore, in this embodiment, the provision of the first concave surface 218 can enhance the contrast of an image viewed from the X direction from the first inclined heated surface 214 to the second flat heated surface 216 of the first seal bar 210, compared to a case in which the +Z side end of the first inclined heated surface 214 and the -Z side end of the second flat heated surface 216 are directly connected without the provision of the first concave surface 218. The contrast of an image viewed from the X direction of an inclined surface such as the first inclined heated surface 214 may be relatively weak. However, the provision of the first concave surface 218 between the first inclined heated surface 214 and the second flat heated surface 216 can enhance the contrast of an image viewed from the X direction from the first inclined heated surface 214 to the second flat heated surface 216, thereby improving the detectability of the image of the first seal bar 210. The same applies to the second seal bar 220.

[0058] Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various other configurations can also be adopted. [Explanation of symbols]

[0059] 100 Battery cell, 110 Battery element, 112 Positive electrode, 113 Positive electrode lead current collector, 114 Negative electrode, 115 Negative electrode lead current collector, 116 Separator, 120 Exterior material, 120a First sealing portion, 120b Second sealing portion, 120c Third sealing portion, 122 First exterior film, 122a First flat portion, 122b First inclined portion, 122c Second flat portion, 122d Third flat portion, 124 Second exterior film, 124a Fourth flat portion, 124b Second inclined portion, 124c Fifth flat portion, 124d Sixth flat portion, 130 First terminal, 132 First flat surface, 134 First inclined surface, 136 Second flat surface, 138 Second inclined surface, 140 Second terminal, 150 First sealing material, 160 Second sealant, 210, 210Z; First seal bar, 212, 212Z; First flat heating surface, 214; First inclined heating surface, 214Z; First vertical surface, 216, 216Z; Second flat heating surface, 218, 218Z; First concave surface, 220, 220Z; Second seal bar, 222, 222Z; Third flat heating surface, 224; Second inclined heating surface, 224Z; Second vertical surface, 226, 26Z; Fourth flat heating surface, 228, 228Z; Second concave surface

Claims

1. A battery element; an exterior material at least partially sealed around the battery element; a terminal electrically connected to the battery element, at least partially drawn out from between the portions of the exterior material, and covered with a sealing material between the portions of the exterior material; Equipped with the terminal has an inclined surface that is inclined from a side where one of the portions of the exterior material is located toward a side where the other of the portions of the exterior material is located, The battery cell, wherein the inclined surface and the portion of the exterior material are at least partially arranged substantially parallel.

2. The battery cell according to claim 1 , wherein the inclined surface is located on both a side where one of the portions of the exterior material is located and a side where the other of the portions of the exterior material is located.

3. a step of at least partially sealing an exterior material around a battery element, wherein a terminal electrically connected to the battery element is at least partially drawn out from between portions of the exterior material, the terminal is covered with a sealing material between the portions of the exterior material, and the terminal has an inclined surface that is inclined from a side where one of the portions of the exterior material is located toward a side where the other of the portions of the exterior material is located; a step of sealing the exterior material, the step of pressing a heating surface of a heating body toward at least one of the portions of the exterior material while the inclined surface and the heating surface are at least partially arranged approximately parallel to each other.

4. 4. The method for manufacturing a battery cell according to claim 3, wherein the heating surface has a first region that is pressed toward at least one of the portions of the exterior material between which the sealing material is located, a second region that is pressed toward at least one of the portions of the exterior material between which the sealing material is not located, and a third region that is located between the first region and the second region and is recessed relative to the second region.

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