JP2020053121A - Lamination type battery and manufacturing method of lamination type battery - Google Patents

Abstract

To provide a lamination type battery in which breakdown of an exterior body is restrained, when a force is applied thereto.SOLUTION: A lamination type battery 1 includes a membrane electrode assembly 2 having first electrode plates and second electrode plates laminated alternately, and an exterior body 3 having a first member 4 and a second member 5, and including a housing region 6 where a housing space 6a for housing the membrane electrode assembly 2 between the first member 4 and the second member 5 is defined, and an encapsulation region 7 located on the outer periphery of the housing region 6, and bonding the first member 4 and the second member 5. The encapsulation region 7 includes an exterior body junction layer bonding a thermosetting resin layer constituting the inside of the first member 4 and the inside of the second member 5. Thickness of the exterior body junction layer at the borderline of the encapsulation region 7 and the housing region 6 is larger than that of exterior body junction layer at the outside end of the encapsulation region 7. The exterior body junction layer includes an exterior body resin protrusion protruding farther to the housing space side than the borderline of the encapsulation region 7 and the housing region 6.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a stacked battery and a method for manufacturing the stacked battery.

  For example, as proposed in Patent Literature 1, a stacked battery in which a positive electrode plate and a negative electrode plate are alternately stacked is widely used. As an example of the stacked battery, a lithium ion secondary battery can be exemplified. One of the features of the lithium ion secondary battery is that it has a larger capacity than other types of stacked batteries. Lithium ion secondary batteries having such characteristics are expected to be widely used in various applications such as in-vehicle applications and stationary housing applications.

  In a stacked battery typified by a lithium ion secondary battery, a membrane electrode assembly having an electrode plate such as a positive electrode plate and a negative electrode plate is housed inside an outer package made of a film containing a thermoplastic resin. I have. The periphery of the exterior body is sealed from the outside by a bonding layer formed by melting the thermoplastic resin by pressing while heating the exterior body.

JP-A-2017-152140

  If the pressing force when pressing the exterior body varies from place to place, a lump of thermoplastic resin projecting toward the inside of the exterior body may be formed in a part of the bonding layer. In such a lump portion, stress is easily concentrated when a force is applied to the exterior body, and it is likely to be a starting point of breakage.

  An object of the present invention is to provide a stacked battery that can effectively solve such a problem.

The stacked battery according to the present invention is
A membrane electrode assembly having a first electrode plate and a second electrode plate alternately stacked;
A housing region having a first member and a second member, wherein a housing space defining the membrane electrode assembly is defined between the first member and the second member; An outer package, comprising: a sealing region located on the outer periphery of the region, where the first member and the second member are joined.
The sealing region includes an exterior body bonding layer in which a thermoplastic resin layer forming an inner surface of the first member and a thermoplastic resin layer forming an inner surface of the second member are bonded.
The thickness of the exterior body bonding layer at the boundary between the sealing region and the housing region is larger than the thickness of the exterior body bonding layer at the outer end of the sealing region.
The exterior body bonding layer is a stacked battery including an exterior body resin protrusion that protrudes toward the housing space from a boundary between the sealing region and the housing region.

  In at least one side of the sealing region of the exterior body of the stacked battery according to the present invention, the exterior body resin protrusion of the exterior body joining layer may extend only one along the one side.

  The outer package resin protrusion of the outer package joining layer of the stacked battery according to the present invention may be formed over the entirety of the at least one side of the sealing region of the outer package.

  In the stacked battery according to the present invention, the thickness of the outer package joining layer may increase from an outer end of the sealing region toward a boundary between the sealing region and the housing region.

  In the stacked battery according to the present invention, a projecting length of the exterior body resin protrusion of the exterior body joining layer toward the housing space may be equal to or greater than a thickness of the thermoplastic resin layer.

  The stacked battery according to the present invention, wherein the stacked battery further includes a tab connected to the membrane electrode assembly and protruding outward from at least one side of the sealing region of the exterior body, wherein the exterior body bonding layer The exterior resin protruding portion may be provided at least on the one side of the sealing region where the tab protrudes.

  In the stacked battery according to the present invention, a sealant positioned between the first member and the second member to cover the tab from the side of the first member, and covers the tab from the side of the second member. And a sealant positioned between the first member and the second member, wherein the sealing region is formed by joining the sealant on the first member side and the sealant on the second member side. Further comprising a bonding layer, the thickness of the sealant bonding layer at the boundary between the sealing region and the housing region is greater than the thickness of the sealant bonding layer at the outer end of the sealing region, the sealant bonding layer, And a sealant protruding portion protruding toward the storage space from a boundary between the sealing region and the storage region.

  In the stacked battery according to the present invention, at least one side of the sealing region of the exterior body, the exterior body resin protrusion and the sealant projection may be integrally formed.

The method for manufacturing a stacked battery according to the present invention includes:
A preparing step of preparing a membrane electrode assembly having a first electrode plate and a second electrode plate alternately stacked;
A housing step of housing the membrane / electrode assembly inside an exterior body having a first member and a second member, wherein the exterior body includes the membrane electrode between the first member and the second member; An accommodation area in which an accommodation space for accommodating the joined body is defined; a sealing area located on the outer periphery of the accommodation area, where the first member and the second member are joined; An opening step, which is located on the outer periphery and includes an opening area where the first member and the second member are not joined,
An electrolyte injection step of injecting an electrolyte into the housing space of the exterior body through the opening region,
In the opening region of the exterior body, using a first heat bar, the first member is pressed toward the second member while heating the first member, and the first member and the second member And a closing step of joining
The sealing region includes an exterior body bonding layer in which a thermoplastic resin layer forming an inner surface of the first member and a thermoplastic resin layer forming an inner surface of the second member are bonded.
The thickness of the exterior body bonding layer at the boundary between the sealing region and the housing region is larger than the thickness of the exterior body bonding layer at the outer end of the sealing region.
A method of manufacturing a stacked battery, wherein the exterior body bonding layer includes an exterior body resin protrusion that protrudes toward the housing space from a boundary between the sealing region and the housing region.

  In the method for manufacturing a stacked battery according to the present invention, the closing step includes a step of pressing the first member toward the second member while heating the first member using a first heat bar, The first heat bar may include an elastic body including an inclined surface facing the first member, and a base supporting the elastic body.

  In the method for manufacturing a stacked battery according to the present invention, the inclined surface of the elastic body may have a distance between the inclined surface and the first member before the first heat bar presses the first member. May be inclined so as to increase toward the accommodation area.

  ADVANTAGE OF THE INVENTION According to the laminated battery of this invention, when a force is applied to an exterior body, it can suppress that an exterior body joining layer is damaged.

FIG. 1 is a view for explaining an embodiment of the present invention, and is a perspective view showing a stacked battery. FIG. 2 is a perspective view showing a membrane electrode assembly included in the stacked battery of FIG. FIG. 3 is a plan view showing a membrane electrode assembly included in the stacked battery of FIG. FIG. 4 is a cross-sectional view showing a membrane electrode assembly included in the stacked battery of FIG. FIG. 5 is a sectional view showing a section taken along line VV of FIG. FIG. 6 is a cross-sectional view illustrating an example of a cross section taken along line AA of the sealing region of the exterior body in FIG. 3. FIG. 7 is a cross-sectional view showing a sealing region of the exterior body in FIG. 6 in an enlarged manner. FIG. 8 is a perspective view showing an example of the exterior body resin protrusion formed on one side of the sealing region of the exterior body. FIG. 9 is a cross-sectional view illustrating an example of a cross section taken along line CC of the sealing region of the exterior body in FIG. 3. FIG. 10 is a cross-sectional view illustrating another example of a cross section taken along line CC of the sealing region of the exterior body in FIG. 3. FIG. 11 is a diagram illustrating a housing step of housing the membrane / electrode assembly inside the exterior body. FIG. 12 is a diagram illustrating a first stage of a joining process of joining the first member and the second member of the exterior body in the housing process. FIG. 13 is a diagram illustrating a second stage of the joining step of joining the first member and the second member of the exterior body in the accommodation step. FIG. 14 is a diagram illustrating a third stage of the joining step of joining the first member and the second member of the exterior body in the housing step. FIG. 15 is a diagram illustrating a first stage of a joining step of joining the first member and the second member of the exterior body in the closing step of closing the opening region of the exterior body. FIG. 16 is a diagram illustrating a second stage of the joining step of joining the first member and the second member of the exterior body in the closing step. FIG. 17 is a diagram showing a third stage of the joining step of joining the first member and the second member of the exterior body in the closing step. FIG. 18 is a cross-sectional view illustrating a modification of the exterior body bonding layer. FIG. 19 is a cross-sectional view illustrating an example of a first heat sealer for forming the exterior body bonding layer illustrated in FIG. 18. FIG. 20 is a cross-sectional view illustrating a modification of the exterior body bonding layer. FIG. 21 is a cross-sectional view showing an example of a first heat sealer for forming the exterior body bonding layer shown in FIG. FIG. 22 is a cross-sectional view illustrating a modification of the second heat sealer used in the closing step. FIG. 23 is a cross-sectional view showing a modification of the second heat sealer used in the closing step. FIG. 24 is a sectional view showing a modification of the second heat sealer used in the closing step. FIG. 25 is a sectional view showing a modification of the second heat sealer used in the closing step.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, in the drawings attached to the present specification, for convenience of understanding, the scales and the dimensional ratios in the vertical and horizontal directions are appropriately changed from those of the actual ones and exaggerated.

  FIG. 1 to FIG. 17 are views for explaining an embodiment of a stacked electrode and a method of manufacturing the same according to the present invention. FIG. 1 is a perspective view showing a specific example of a stacked battery. The stacked battery 1 includes a membrane electrode assembly 2, an exterior body 3 that houses the membrane electrode assembly 2, tabs 16 and 26 attached to the membrane electrode assembly 2, and a sealant attached to the tabs 16 and 26. 18, 28. The tabs 16 and 26 and the sealants 18 and 28 partially extend from the inside of the exterior body 3 to the outside.

  FIG. 2 is a perspective view showing the membrane electrode assembly 2 housed in the exterior body 3 in FIG. 1, and the exterior body 3 is indicated by a two-dot chain line. FIG. 3 is a plan view showing the stacked battery 1. Hereinafter, each component of the stacked battery 1 will be described.

(Membrane electrode assembly)
The membrane electrode assembly 2 includes a first electrode plate 10 and a second electrode plate 20 that are alternately stacked. In the present embodiment, an example in which the membrane electrode assembly 2 forms a lithium ion secondary battery will be described. In this example, the first electrode plate 10 constitutes a positive electrode plate 10X, and the second electrode plate 20 constitutes a negative electrode plate 20Y. However, as can be understood from the description of the operation and effect described below, the embodiment described here is not limited to the lithium ion secondary battery, and the first electrode plate 10 and the second electrode plate 20 can be widely applied to the membrane electrode assembly 2 in which the layers 20 are alternately stacked.

  FIG. 4 is a sectional view showing the membrane electrode assembly 2. As shown in FIGS. 2 to 4, the membrane electrode assembly 2 has a plurality of positive plates 10X (first electrode plates 10) and a plurality of negative plates 20Y (second electrode plates 20). The positive electrode plates 10X and the negative electrode plates 20Y are alternately arranged along the stacking direction dL (see FIG. 4). The membrane electrode assembly 2 and the stacked battery 1 have a flat shape as a whole, have a small thickness in the stacking direction dL, and extend in directions d1 and d2 perpendicular to the stacking direction dL.

  In the illustrated non-limiting example, the positive electrode plate 10X and the negative electrode plate 20Y have a rectangular outer contour. The positive electrode plate 10X and the negative electrode plate 20Y have a longitudinal direction in a first direction d1, which is a direction in which the tabs 16 and 26 extend, which are orthogonal to the laminating direction dL, and are orthogonal to both the laminating direction dL and the first direction d1. It has a short direction in two directions d2. The positive electrode plate 10X and the negative electrode plate 20Y are displaced in the first direction d1. More specifically, the plurality of positive electrode plates 10X are disposed closer to one side (upper right side in FIG. 2) in the first direction d1, and the plurality of negative electrode plates 20Y are disposed on the other side (FIG. 2) in the first direction d1. (Lower left side of the camera). The positive electrode plate 10X and the negative electrode plate 20Y overlap in the stacking direction dL at the center in the first direction d1.

  The positive electrode plate 10X (first electrode plate 10) has a sheet-like outer shape as illustrated. The positive electrode plate 10X (first electrode plate 10) includes a positive electrode current collector 11X (first electrode current collector 11) and a positive electrode active material layer 12X (first electrode active material layer) provided on the positive electrode current collector 11X. 12). In the lithium ion secondary battery, the positive electrode plate 10X emits lithium ions when discharging and occludes lithium ions when charging.

  The positive electrode current collector 11X has a first surface 11a and a second surface 11b facing each other as main surfaces. The positive electrode active material layer 12X is formed on at least one of the first surface 11a and the second surface 11b of the positive electrode current collector 11X. Specifically, when the first surface 11a or the second surface 11b of the positive electrode current collector 11X forms the outermost surface in the stacking direction dL of the membrane electrode assembly 2, the surface of the positive electrode current collector 11X Does not have the positive electrode active material layer 12X. Except for the configuration related to the arrangement of the positive electrode current collector 11X, the plurality of positive electrode plates 10X included in the stacked battery 1 have the positive electrode active material layers 12X on both sides of the positive electrode current collector 11X and have the same configuration. Can be done.

The positive electrode current collector 11X and the positive electrode active material layer 12X can be manufactured by various manufacturing methods using various materials applicable to the stacked battery 1 (lithium ion secondary battery). As an example, the positive electrode current collector 11X can be formed of an aluminum foil. The positive electrode active material layer 12X contains, for example, a positive electrode active material, a conductive additive, and a binder serving as a binder. The positive electrode active material layer 12X is formed by applying a positive electrode slurry obtained by dispersing a positive electrode active material, a conductive auxiliary agent, and a binder in a solvent onto a material forming the positive electrode current collector 11X and solidifying the slurry. Can be done. As the positive electrode active material, for example, a lithium metal oxide compound represented by a general formula LiM _x O _y (where M is a metal and x and y are the composition ratio of metal M and oxygen O) is used. Specific examples of the lithium metal oxide compound include lithium cobaltate, lithium nickelate, lithium manganate and the like. Acetylene black or the like can be used as the conductive assistant. As the binder, polyvinylidene fluoride or the like can be used.

  As shown in FIG. 2, the positive electrode current collector 11X (first electrode current collector 11) has a first connection region a1 and a first effective region b1 adjacent to the first connection region a1. The positive electrode active material layer 12X (first electrode active material layer 12) is disposed only in the first effective region b1 of the positive electrode current collector 11X. The first connection region a1 and the first effective region b1 are arranged in the longitudinal direction of the positive electrode plate 10X. The first connection region a1 is located outside the first effective region b1 in the longitudinal direction of the positive electrode plate 10X (upper right side in FIG. 2). The plurality of positive electrode current collectors 11X are joined and electrically connected in the first connection region a1 by resistance welding, ultrasonic welding, sticking with tape, fusion, or the like. On the other hand, the first effective region b1 is located in a region of the negative electrode plate 20Y facing a negative electrode active material layer 22Y described later. With such an arrangement of the first effective region b1, precipitation of lithium from the positive electrode active material layer 12X can be prevented.

  Next, the negative electrode plate 20Y (second electrode plate 20) will be described. The negative electrode plate 20Y also has a sheet-like outer shape, similarly to the positive electrode plate 10X. The negative electrode plate 20Y (second electrode plate 20) includes a negative electrode current collector 21Y (second electrode current collector 21) and a negative electrode active material layer 22Y (second electrode active material layer) provided on the negative electrode current collector 21Y. 22). In the lithium ion secondary battery, the negative electrode plate 20Y occludes lithium ions during discharging and releases lithium ions during charging.

  The negative electrode current collector 21Y has a first surface 21a and a second surface 21b facing each other as main surfaces. The negative electrode active material layer 22Y is formed on at least one of the first surface 21a and the second surface 21b of the negative electrode current collector 21Y. The plurality of negative electrode plates 20Y included in the stacked battery 1 can be configured identically as having a pair of negative electrode active material layers 22Y provided on both sides of the negative electrode current collector 21Y.

  The negative electrode current collector 21Y and the negative electrode active material layer 22Y can be manufactured by various manufacturing methods using various materials applicable to the stacked battery 1 (lithium ion secondary battery). As an example, the negative electrode current collector 21Y is formed of, for example, a copper foil. The negative electrode active material layer 22Y includes, for example, a negative electrode active material made of a carbon material and a binder functioning as a binder. The negative electrode active material layer 22Y forms, for example, a negative electrode slurry formed by dispersing a negative electrode active material composed of carbon powder, graphite powder, and the like and a binder such as polyvinylidene fluoride in a solvent, as a negative electrode current collector 21Y. It can be produced by coating and solidifying on a material.

  As shown in FIG. 2, the negative electrode current collector 21Y (second electrode current collector 21) has a second connection region a2 and a second effective region b2 adjacent to the second connection region a2. The negative electrode active material layer 22Y (second electrode active material layer 22) is disposed in the second effective area b2 of the negative electrode current collector 21Y. The second connection region a2 and the second effective region b2 are arranged in the longitudinal direction of the negative electrode plate 20Y. The second connection region a2 is located outside the second effective region b2 in the longitudinal direction of the negative electrode plate 20Y (the lower left side in FIG. 2). The plurality of negative electrode current collectors 21Y are joined and electrically connected to each other in the second connection region a2 by resistance welding, ultrasonic welding, tape bonding, fusion, or the like. On the other hand, the second effective region b2 extends to a region facing the positive electrode active material layer 12X of the positive electrode plate 10X.

  As shown in FIG. 4, at least one of the positive electrode plate 10X (the first electrode plate 10) and the negative electrode plate 20Y (the second electrode plate 20) may have an insulator (insulating layer) 30. The insulator 30 prevents a short circuit between the positive electrode plate 10X (the first electrode plate 10) and the negative electrode plate 20Y (the second electrode plate 20). In the illustrated example, the negative electrode plate 20Y has the insulator 30. The insulator 30 is provided so as to cover the pair of negative electrode active material layers 22Y included in each negative electrode plate 20Y. The surface of the negative electrode plate 20Y facing the positive electrode active material layer 12X of the positive electrode plate 10X in the stacking direction dL is formed by the insulator 30. However, the insulator 30 that covers the pair of positive electrode active material layers 12X included in each positive electrode plate 10X can be provided instead of the illustrated insulator 30 or in addition to the illustrated insulator 30.

  In the illustrated example, the insulator 30 also functions as the electrolyte layer 30A. The electrolyte layer 30A (insulator 30) is a layer formed by solidifying or gelling the electrolytic solution applied on the active material layers 22Y and 12X on the active material layers 22Y and 12X. As the electrolyte, for example, a polymer matrix and a non-aqueous electrolyte solution (that is, a non-aqueous solvent and an electrolyte salt), which are gelled to give a sticky surface, or a polymer matrix and a non-aqueous solvent , A solid electrolyte can be used. The specific material for producing the electrolyte layer 30A (insulator 30) is not particularly limited, and various materials used for forming the same (for example, disclosed in JP-A-2012-190567). Material).

(tab)
The tabs 16 and 26 include a first tab 16 electrically connected to the positive electrode current collector 11X and a second tab 26 electrically connected to the negative electrode current collector 21Y. FIG. 5 is a sectional view showing a section taken along line VV of FIG. The two-dot chain line shown in FIG. 5 shows an example of the position of the first member 4 and the second member 5 of the exterior body 3. In the example shown in FIG. 5, the first tab 16 is connected to the second surface 11b (lower surface) of the lowermost positive electrode plate 10X in the first connection region a1. Although not shown, the second tab 26 is also connected to the second surface 21b (lower surface) of the lowermost negative electrode plate 20Y in the second connection region a2. In addition, the attachment method of the first tab 16 is arbitrary as long as the positive electrode current collector 11X and the first tab 16 can be electrically connected. Similarly, the attachment method of the second tab 26 is arbitrary as long as the negative electrode current collector 21Y and the second tab 26 can be electrically connected.

  As shown in FIG. 5, the first tab 16 extends between the first member 4 and the second member 5 of the exterior body 3 and extends from the inside of the exterior body 3 to the outside in the first direction d1. Although not shown, the second tab 26 extends from the inside of the exterior body 3 to the outside in the first direction d1 so as to pass between the first member 4 and the second member 5 of the exterior body 3. I have. The first tab 16 functions as a positive terminal of the stacked battery 1, and the second tab 26 functions as a negative terminal of the stacked battery 1.

  The first tab 16 and the second tab 26 can be formed using, for example, aluminum, nickel, a copper alloy, nickel-plated copper, or the like. For example, when the positive electrode current collector 11X is formed of aluminum foil and the negative electrode current collector 21Y is formed of copper foil, the first tab 16 is formed using aluminum, and the second tab 16 is formed using copper alloy. 26 can be formed. The thickness of the first tab 16 and the second tab 26 is, for example, 0.2 mm or more, and may be 2.0 mm or less.

(Sealant)
The sealants 18 and 28 are members made of a material that can be welded to the exterior body 3. Examples of the material of the sealants 18 and 28 include polypropylene, modified polypropylene, low-density polypropylene, ionomer, and ethylene / vinyl acetate. The thickness of the sealants 18 and 28 is, for example, 0.05 mm or more, and may be 0.4 mm or less.

  The sealants 18 and 28 include the first sealant 18 located between the first tab 16 and the exterior body 3 and the second sealant 28 located between the second tab 26 and the exterior body 3. As shown in FIG. 5, a first sealant 18 is interposed between the exterior body 3 and the first tab 16 in the seal portion 3a. Although not shown, a second sealant 28 is interposed between the exterior body 3 and the second tab 26. Thereby, the exterior body 3 can be more strongly sealed around the tabs 16 and 26. In addition, it is possible to suppress a short circuit between the tabs 16 and 26 and a metal foil such as an aluminum foil or a stainless steel foil included in the exterior body 3.

(Exterior)
The outer package 3 is a packaging material for sealing the membrane / electrode assembly 2 from the outside. As shown in FIG. 1, the exterior body 3 includes a sheet-shaped first member 4 located above the membrane electrode assembly 2 and a sheet-shaped second member 5 located below the membrane electrode assembly 2. And The first member 4 and the second member 5 are joined to each other along the outer edge so as to surround the membrane electrode assembly 2 in a plan view.

  In the following description, in the exterior body 3, a region defining a housing space 6 a for housing the membrane electrode assembly 2 between the first member 4 and the second member 5 is also referred to as a housing region 6. Name. In addition, a region of the exterior body 3 that is located on the outer periphery of the housing region 6 and in which the first member 4 and the second member 5 are joined is also referred to as a sealing region 7. In FIG. 3, the sealing region 7 is indicated by hatching. The first member 4 and the second member 5 are joined by melting the thermoplastic resin contained in the first member 4 and the second member 5 by pressing the first member 4 and the second member 5 while heating. This is realized by so-called heat sealing.

  As shown in FIG. 3, the exterior body 3 may have a square shape including four sides in a plan view. Further, the tabs 16 and 26 may extend outward from a pair of opposing sides of the exterior body 3, respectively. In this case, the sealing region 7 of the exterior body 3 includes a first sealing area 7 a extending along one side of the side of the exterior body 3 where the tabs 16 and 26 do not extend, and a sealing area 7 of the side of the exterior body 3. It includes a pair of second sealing regions 7b extending along a pair of sides from which the tabs 16 and 26 extend, and a third sealing region 7c facing the first sealing region 7a. The tabs 16 and 26 do not extend even in the third sealing region 7c. In the present embodiment, as will be described later, first, the first sealing region 7a and the second sealing region 7b are formed, and subsequently, the electrolytic solution is injected into the exterior body 3; Stop region 7c is formed.

  The structure of the exterior body 3 will be described in detail. FIG. 6 is a cross-sectional view showing an example of a cross section taken along line AA of the first sealing region 7a of the exterior body 3 of FIG.

  First, the first member 4 and the second member 5 of the exterior body 3 will be described. As shown in FIG. 6, the first member 4 includes a base material 4a and a thermoplastic resin layer 4b located closer to the accommodation space 6a than the base material 4a. Similarly, the second member 5 includes a base member 5a and a thermoplastic resin layer 5b located closer to the accommodation space 6a than the base member 5a.

  The substrates 4a and 5a include rigid plastic films such as nylon and PET (polyethylene terephthalate). The substrates 4a and 5a may further include a metal foil located closer to the accommodation space 6a than the plastic film. Examples of the metal foil include an aluminum foil and a stainless steel foil.

  The thermoplastic resin layers 4b and 5b are layers containing a thermoplastic resin. As shown in FIG. 6, the thermoplastic resin layers 4b and 5b located in the sealing region 7 such as the first sealing region 7a are melted by heating to form a bonding layer indicated by reference numeral 8. I have. Examples of the thermoplastic resin include polypropylene, modified polypropylene, low-density polypropylene, ionomer, ethylene / vinyl acetate, and the like. In the following description, a bonding layer formed by melting the thermoplastic resin layers 4b and 5b is also referred to as an exterior body bonding layer 8.

Next, the structure of the exterior body bonding layer 8 located in the first sealing region 7a of the sealing region 7 will be described. In FIG. 6, reference symbol T1 indicates the thickness of the exterior body bonding layer 8 at the boundary between the sealing region 7 and the housing region 6. Reference symbol T2 represents the thickness of the exterior body bonding layer 8 at the end outside the sealing region 7. Both the thickness T1 and the thickness T2 are smaller than the thickness of the original thermoplastic resin layers 4b and 5b. That is, the exterior body bonding layer 8 is compressed as compared with the original thermoplastic resin layers 4b and 5b. For example, when the thickness of the original thermoplastic resin layers 4b and 5b is T3, both the thickness T1 and the thickness T2 are 0.9 times or less of the thickness T3 × 2 (T3 × 2 × 0.9 or less). is there. Thereby, the strength of the exterior body bonding layer 8 can be secured.
As shown in FIG. 6, the thickness T1 is larger than the thickness T2. For example, the thickness T1 is at least 1.05 times the thickness T2, preferably at least 1.1 times, more preferably at least 1.15 times.

  The thickness of the exterior body bonding layer 8 may increase from the outer end of the sealing region 7 toward the boundary between the sealing region 7 and the housing region 6. In the example shown in FIG. 6, the thickness of the exterior body bonding layer 8 monotonically increases from the outer end of the sealing region 7 to the boundary between the sealing region 7 and the housing region 6.

  By making the thickness T1 of the exterior body bonding layer 8 at the boundary between the sealing region 7 and the housing region 6 larger than the thickness T2 of the exterior body bonding layer 8 at the outer end of the sealing region 7, The rigidity of the exterior body bonding layer 8 at the boundary between the housing body 6 and the housing region 6 can be relatively increased. Accordingly, it is possible to prevent the exterior body bonding layer 8 at the boundary between the sealing region 7 and the accommodation region 6 from being damaged due to an increase in the internal pressure of the accommodation space 6a of the exterior body 3 or the like.

  Further, as shown in FIG. 6, the exterior body bonding layer 8 includes an exterior body resin protrusion 8a that protrudes from the boundary between the sealing region 7 and the accommodation region 6 toward the accommodation space 6a. Such an exterior body resin protrusion 8a can also contribute to suppressing damage to the exterior body joining layer 8 at the boundary between the sealing region 7 and the housing region 6.

  FIG. 7 is an enlarged cross-sectional view showing the exterior body bonding layer 8 of the exterior body 3 of FIG. In FIG. 7, a first heat bar 41 that presses the first member 4 while heating it to melt the thermoplastic resin layer 4b is shown by a dotted line. As shown in FIG. 7, the boundary between the sealing region 7 and the housing region 6 may be defined as an end of the housing space 6a of the region of the first member 4 pressed by the first heat bar 41. Further, the boundary between the sealing region 7 and the housing region 6 may be defined as a bent portion generated in the first member 4 by being pressed by the first heat bar 41.

  In FIG. 7, reference symbol S <b> 1 indicates the length of the exterior body resin protrusion 8 a of the exterior body bonding layer 8 protruding toward the housing space 6 a. Preferably, the projecting length S1 of the exterior resin projecting portion 8a is not less than the thickness T3 of the thermoplastic resin layers 4b, 5b located in the housing area 6. For example, the protrusion length S1 of the exterior resin protrusion 8a is at least 1.0 times, preferably at least 1.5 times the thickness T3 of the thermoplastic resin layers 4b, 5b located in the housing area 6, It is more preferably at least 2.0 times.

  As shown in FIG. 7, the exterior body resin protrusion 8a of the exterior body joining layer 8 may have a curved surface so as to be convex toward the accommodation space 6a side. Thus, it is possible to suppress the formation of cracks such as cracks on the surface of the exterior body resin protrusion 8a due to an increase in the internal pressure of the housing space 6a.

  FIG. 8 is a perspective view illustrating an example of the exterior body resin protrusion 8a formed in the first sealing area 7a which is one side of the sealing area 7 of the exterior body 3. As shown in FIG. 8, the exterior body resin protrusion 8 a preferably extends along the side of the sealing region 7. If the exterior resin protrusion 8a is formed intermittently along the side of the sealing region 7, the rigidity of the portion of the sealing region 7 where the exterior resin protrusion 8a is not formed is relatively high. It is thought that it becomes easy to become the starting point of breakage. As shown in FIG. 8, since the exterior body resin protrusion 8 a extends along the side of the sealing region 7, it is possible to suppress the occurrence of variation in the rigidity of the sealing region 7 and damage the sealing region 7. Can be suppressed.

  Preferably, on one side of the sealing region 7 of the exterior body 3, only one exterior body resin protrusion 8a of the exterior body joining layer 8 extends along the one side. More preferably, the exterior body resin protrusion 8a of the exterior body joining layer 8 is formed over the entire area of the one side. Thereby, it is possible to further suppress the occurrence of variation in rigidity on one side of the sealing region 7 of the exterior body 3. In each side of the sealing region 7 of the exterior body 3, it is not necessary that only one exterior body resin projection 8 a is provided, and it is also necessary that the exterior body resin projection 8 a is formed over the entire side. Absent. It is necessary that at least one side of the sealing region 7 having only one exterior resin projecting portion 8a and at least one side of the sealing region 7 having the entire exterior resin projecting portion 8a formed therein. preferable.

  FIGS. 6 to 8 show an example in which the exterior body resin protrusion 8a is formed in the first sealing area 7a of the sealing area 7, but the side on which the exterior body resin projection 8a is formed is particularly large. There is no limit. For example, the exterior resin protrusion 8a may be formed in a cross section along the line BB in FIG. 3, that is, in the second sealing region 7b where the tabs 16 and 26 project. Further, the exterior body resin protrusion 8a may be formed in the third sealing area 7c of the sealing area 7.

  Next, the structure of a portion of the second sealing region 7b of the sealing region 7 where the sealants 18 and 28 are stacked will be described with reference to FIG. FIG. 9 is a cross-sectional view showing an example of a cross section of the second sealing region 7b of the exterior body 3 of FIG. 3 along the line CC. In FIG. 9, the structure of the portion of the second sealing region 7b where the first sealant 18 is laminated will be described. The structure of the portion where the second sealant 28 is laminated in the second sealing region 7b is the same as the structure of the portion where the first sealant 18 is laminated in the second sealing region 7b. Omitted.

  As shown in FIG. 9, the portion of the second sealing region 7 b where the first sealant 18 is laminated is formed by the first sealant 18 on the first member 4 side and the first sealant 18 on the second member 5 side. It has a bonding layer that is bonded. In the following description, a bonding layer formed by melting the first sealant 18 on the first member 4 side and the first sealant 18 on the second member 5 side is also referred to as a sealant bonding layer 9.

In FIG. 9, reference symbol U1 represents the thickness of the sealant bonding layer 9 at the boundary between the sealing region 7 and the housing region 6. Reference symbol U2 represents the thickness of the sealant bonding layer 9 at the outer end of the sealing region 7. Each of the thickness U1 and the thickness U2 is smaller than the thickness of the original first sealant 18. That is, the sealant bonding layer 9 is compressed as compared with the original first sealant 18. For example, when the thickness of the original first sealant 18 is U3, both the thickness U1 and the thickness U2 are 0.9 times or less of the thickness U3 × 2 (T3 × 2 × 0.9 or less). Thereby, the strength of the sealant bonding layer 9 can be ensured.
Further, similarly to the case of the exterior body bonding layer 8, the thickness U1 is preferably larger than the thickness U2. For example, the thickness U1 is at least 1.05 times the thickness U2, preferably at least 1.10 times, and more preferably at least 1.15 times. Thereby, the rigidity of the sealant bonding layer 9 at the boundary between the sealing region 7 and the housing region 6 can be relatively increased. Therefore, it is possible to prevent the sealant bonding layer 9 at the boundary between the sealing region 7 and the housing region 6 from being damaged due to an increase in the internal pressure of the housing space 6a of the exterior body 3 or the like.

  As in the case of the exterior body bonding layer 8, the thickness of the sealant bonding layer 9 may increase from the outer end of the sealing region 7 toward the boundary between the sealing region 7 and the housing region 6. In the example shown in FIG. 9, the thickness of the sealant bonding layer 9 monotonically increases from the outer end of the sealing region 7 to the boundary between the sealing region 7 and the housing region 6.

  Further, similarly to the case of the exterior body bonding layer 8, the sealant bonding layer 9 may include a sealant resin protrusion 9 a that protrudes toward the housing space 6 a from the boundary between the sealing region 7 and the housing region 6. . The projecting length of the sealant resin projecting portion 9a toward the housing space 6a is preferably not less than the thickness T3 of the thermoplastic resin layers 4b and 5b located in the housing area 6. For example, the projecting length of the sealant resin projecting portion 9a is at least 1.0 times, preferably at least 1.5 times, the thickness T3 of the thermoplastic resin layers 4b, 5b located in the housing area 6, and more preferably. Is 2.0 times or more.

FIG. 10 is a cross-sectional view showing another example of a cross section taken along line CC of the second sealing region 7b of the exterior body 3 of FIG. As shown in FIG. 10, the sealant bonding layer 9 includes not only a portion formed by melting the first sealant 18 but also a thermoplastic resin layer 4 b of the first member 4 and a thermoplastic resin layer of the second member 5. 5b may include a portion formed by melting. In this case, both the thickness U1 and the thickness U2 of the sealant bonding layer 9 are smaller than the thicknesses of the original first sealant 18 and the thermoplastic resin layers 4b and 5b. That is, the sealant bonding layer 9 is compressed as compared with the original first sealant 18 and the thermoplastic resin layers 4b and 5b. For example, when the thickness of the original first sealant 18 is U3 and the thickness of the original thermoplastic resin layers 4b and 5b is T3, both the thickness U1 and the thickness U2 are the thickness U2 × 2 and the thickness T3. It is 0.9 times or less the sum of × 2 ((U3 × 2 + T3 × 2) × 0.9 or less). Thereby, the strength of the sealant bonding layer 9 can be ensured.
In the example shown in FIG. 10, similarly to the example shown in FIG. 9, the projecting length of the sealant resin projecting portion 9 a toward the accommodation space 6 a is preferably the thermoplastic resin layer located in the accommodation region 6. 4b and 5b are equal to or more than the thickness T3. For example, the projecting length of the sealant resin projecting portion 9a is at least 1.0 times, preferably at least 1.5 times, the thickness T3 of the thermoplastic resin layers 4b, 5b located in the housing area 6, and more preferably. Is 2.0 times or more.

  Preferably, the sealant bonding layer 9 in the second sealing region 7b is formed integrally with the exterior body bonding layer 8 formed in the second sealing region 7b around the first sealant 18. Similarly, the sealant resin protrusion 9a of the second sealing region 7b is formed integrally with the exterior resin protrusion 8a formed in the second sealing region 7b around the first sealant 18. Thereby, the rigidity of the exterior body bonding layer 8 and the sealant bonding layer 9 at the boundary between the second sealing region 7b and the housing region 6 can be further increased.

  Next, a method for manufacturing the stacked battery 1 according to the present embodiment configured as a lithium ion secondary battery will be described. The manufacturing method of the stacked battery described below includes a membrane electrode assembly preparing step of preparing the membrane electrode assembly 2 and the first tab 16 and the second tab 26 being connected to the first connection region a1 of the positive electrode current collector 11X. A tab attaching step of attaching the negative electrode current collector 21Y to the second connection area a2, a housing step of housing the membrane electrode assembly 2 inside the exterior body 3, and a housing of the electrolyte through the opening area of the exterior body 3 The method includes a step of injecting an electrolytic solution into the space and a step of joining an opening region of the exterior body 3 to seal the exterior body 3. Hereinafter, each step will be described.

(Membrane electrode assembly preparation step)
The membrane electrode assembly preparing step includes the steps of manufacturing the positive electrode plate 10X (first electrode plate 10) and the negative electrode plate 20Y (second electrode plate 20), and the positive electrode plate 10X (first electrode plate 10) and the negative electrode plate 20Y. (A step of alternately laminating the (second electrode plates 20)).

  First, the steps of manufacturing the positive electrode plate 10X (the first electrode plate 10) and the negative electrode plate 20Y (the second electrode plate 20) will be described. The positive electrode plate 10X and the negative electrode plate 20Y may be manufactured at different timings by different processes. In addition, the positive electrode plate 10X and the negative electrode plate 20Y are manufactured in parallel and simultaneously, and the manufactured positive electrode plate 10X and the negative electrode plate 20Y are sequentially supplied to the step of alternately stacking the positive electrode plate 10X and the negative electrode plate 20Y. It may be.

  For example, the positive electrode plate 10X solidifies by coating a composition (slurry) that will form the positive electrode active material layer 12X on a long aluminum foil that will form the positive electrode current collector 11X, Next, it can be produced by cutting into a desired size. Similarly, the negative electrode plate 20Y is formed by, for example, applying a composition (slurry) that will form the negative electrode active material layer 22Y on a long copper foil that will form the negative electrode current collector 21Y. It can be made by solidifying and then cutting to the desired size. In addition, when the insulator 30 functioning as the electrolyte layer 30A is provided to at least one of the positive electrode plate 10X and the negative electrode plate 20Y, on the long material before cutting or after cutting which becomes the electrode plates 10 and 20 The insulator 30 can be manufactured by applying and solidifying or gelling the electrolytic solution on the sheet material.

Next, a step of alternately stacking the positive electrode plates 10X and the negative electrode plates 20Y is performed. In this step, the positive electrode plate 10X and the negative electrode plate 20Y are stacked such that the positive electrode active material layer 12X of the positive electrode plate 10X faces the negative electrode active material layer 22Y of the negative electrode plate 20Y.
Next, the first connection regions a1 of the plurality of positive electrode current collectors 11X are joined to each other by resistance welding, ultrasonic welding, or the like. The same applies to the plurality of negative electrode current collectors 21Y.
Thus, the membrane electrode assembly 2 in which the plurality of positive plates 10X and the plurality of negative plates 20Y are alternately stacked can be obtained.

(Tab mounting process)
In the tab attaching step, first, the first tab 16 and the second tab 26 provided with the first sealant 18 and the second sealant 28 are prepared. Subsequently, the membrane electrode assembly 2 is aligned with the first tub 16 such that the first sealant 18 faces the first connection region a1 of the positive electrode current collector 11X in the first direction d1. After the alignment, the first tab 16 is attached to the first connection region a1 of the positive electrode current collector 11X by resistance welding, ultrasonic welding, or the like. Thereby, the first tab 16 can be electrically connected to the positive electrode current collector 11X. Similarly, the second tab 26 is attached to the second connection region a2 of the negative electrode current collector 21Y, and the second tab 26 is electrically connected to the negative electrode current collector 21Y.

(Containment process)
In the sealing step, first, the membrane electrode assembly 2 to which the first tab 16 and the second tab 26 are attached is arranged between the first member 4 and the second member 5. Subsequently, in a state where the first tab 16 and the second tab 26 are extended to the outside, the inner surface of the first member 4 and the second member are formed along three sides of the periphery of the first member 4 and the second member 5. Then, a bonding step of bonding the inner surface of No. 5 to the inner surface by thermal welding is performed. Thereby, the above-mentioned exterior body bonding layer 8 and sealant bonding layer 9 can be formed. As a result, as shown in FIG. 11, a sealing region 7 including a first sealing region 7 a and a pair of second sealing regions 7 b is provided, and a film is formed in a housing space of the housing region 6 surrounded by the sealing region 7. The exterior body 3 in which the electrode assembly 2 is accommodated can be obtained. Note that the inner surface of the first member 4 and the inner surface of the second member 5 are not yet joined to each other on one side of the outer periphery of the exterior body 3, forming an open area 3 b.

  With reference to FIGS. 12 to 14, the joining step of the accommodation step will be described in detail. First, the first heat sealer 40 used for performing the joining step of the accommodation step will be described. The first heat sealer 40 has a first heat bar 41 that presses the first member 4 toward the second member 5 while heating the first member 4, and a second heat bar 46 that supports the second member 5. . The first heat bar 41 moves along the thickness direction of the first member 4 and presses the first member 4. Similarly to the first heat bar 41, the second heat bar 46 may press the second member 5 toward the first member 4 while heating the second member 5.

  As shown in FIG. 12, the first heat bar 41 includes an inclined surface 41a facing the first member 4. The inclined surface 41a is inclined with respect to the surface direction of the first member 4 such that the distance between the inclined surface 41a and the first member 4 increases toward the accommodation area 6 side. The inclination angle of the inclined surface 41a with respect to the plane direction of the first member 4 is, for example, 0.2 ° or more and 2 ° or less. In this case, when the first heat bar 41 is moved to the first member 4 side, as shown in FIG. 13, the portion of the first member 4 located outside is located on the accommodation region 6 side of the first member 4. Heat is applied and pressed by the first heat bar 41 before the portion to be heated. For this reason, the exterior body bonding layer 8 is formed in a portion located on the outside of the first member 4. FIG. 14 shows a state where the first heat bar 41 is moved to the first member 4 side until the portion of the first member 4 located on the accommodation area 6 side is also heated and pressed by the first heat bar 41. ing.

  By the way, while the first member 4 is being heated and pressed from the first heat bar 41, the thermoplastic resin layer 4b of the first member 4 and the thermoplastic resin layer 5b of the second member 5 are molten. The thermoplastic resin in a molten state has fluidity. Further, the first heat bar 41 has the inclined surface 41a as described above. Therefore, the thermoplastic resin in the molten state receives a force from the outside toward the housing space 6a. As a result, the molten thermoplastic resin is extruded from the boundary between the sealing region 7 and the housing region 6 toward the housing space 6a. In this way, as shown in FIG. 14, the above-mentioned exterior body resin protrusion 8a projecting toward the housing space 6a from the boundary between the sealing region 7 and the housing region 6 is formed. Further, the thickness of the exterior body bonding layer 8 at the boundary between the sealing region 7 and the housing region 6 is larger than the thickness of the exterior body bonding layer 8 at the end outside the sealing region 7.

  Preferably, the first heat bar 41 having the inclined surface 41a is used at least when forming the exterior body bonding layer 8 of the second sealing region 7b from which the tabs 16 and 26 project. The second sealing area 7b from which the tabs 16 and 26 protrude exerts a force when joining the first member 4 and the second member 5 by the thickness of the tabs 16 and 26 as compared with other areas. Hard to add. Here, according to the present embodiment, by using the first heat bar 41 having the inclined surface 41a, the first member 4 can be formed around the tabs 16 and 26, particularly at the portion outside the second sealing region 7b. Can be sufficiently pressed toward the second member 5. Therefore, the bonding strength of the exterior body bonding layer 8 in the second sealing region 7b can be sufficiently ensured.

(Electrolyte injection step)
In the electrolyte injection step, the electrolyte is injected into the housing space 6a inside the exterior body 3 through the opening region 3b of the exterior body 3 shown in FIG.

(Close process)
In the closing step, a joining step of joining the inner surface of the first member 4 and the inner surface of the second member 5 in the opening region 3b by thermal welding is performed. Thereby, the third sealing region 7c including the exterior body bonding layer 8 that closes the opening region 3b can be formed. Thus, the stacked battery 1 including the membrane electrode assembly 2 sealed inside the outer package 3 can be manufactured.

  By the way, in the above-described electrolyte solution injection step, the electrolyte solution may adhere to the inner surface of the first member 4 or the inner surface of the second member 5 in the opening region 3b. When the first member 4 and the second member 5 are heated and pressed in a state where the electrolytic solution is attached, a portion where the outer package joining layer 8 is not formed in the third sealing region 7c or the third sealing region 7c It is conceivable that the bonding strength of the exterior body bonding layer 8 is reduced.

  In consideration of such a problem, it is preferable that the joining step of the closing step is performed so as to remove the electrolytic solution attached to the inner surface of the first member 4 or the inner surface of the second member 5. Hereinafter, an example of the joining step of the closing step will be described in detail. First, the second heat sealer 50 used for performing the joining process of the closing process will be described with reference to FIG.

  As shown in FIG. 15, the second heat sealer 50 heats the first member 4 and presses the first member 4 toward the second member 5, and the second heat sealer 50 supports the second member 5. And two heat bars 56. The first heat bar 51 moves along the thickness direction of the first member 4 and presses the first member 4. Similarly to the first heat bar 51, the second heat bar 56 may press the second member 5 toward the first member 4 while heating the second member 5.

  As shown in FIG. 15, the first heat bar 51 has an elastic body 53 including an inclined surface 51 a facing the first member 4, and a base 52 supporting the elastic body 53. The elastic body 53 is a member having a lower elastic coefficient than the base 52. Examples of the material forming the elastic body 53 include rubber such as fluorine rubber and silicon rubber. The thickness K of the elastic body 53 is, for example, 2 mm or more and 10 mm or less. Examples of the material forming the base 52 include metals such as stainless steel and copper. Similarly to the first heat bar 51, the second heat bar 56 may include an elastic body 58 facing the second member 5 and a base 57 supporting the elastic body 58.

  The inclined surface 51a of the elastic body 53 is inclined with respect to the surface direction of the first member 4 such that the distance between the inclined surface 51a and the first member 4 increases toward the accommodation area 6 side. The inclination angle of the inclined surface 51a of the elastic body 53 with respect to the plane direction of the first member 4 is, for example, 0.2 ° or more and 2 ° or less.

  In FIG. 15, reference numeral 53 a denotes an end of the surface of the elastic body 53 facing the first member 4 on the accommodation region 6 side, and reference numeral 53 b denotes a surface of the elastic body 53 facing the first member 4. The end farther from the accommodation area 6, that is, the outer end is shown. In the example shown in FIG. 15, the inclined surface 51a extends from the end 53a of the surface of the elastic body 53 on the accommodation space 6a side to the outer end 53b. That is, the inclined surface 51 a forms the entire area of the surface of the elastic body 53 that faces the first member 4 and contacts the first member 4. Note that the inclined surface 51 a may be a part of the surface of the elastic body 53 that faces the first member 4 and contacts the first member 4.

  In FIG. 15, reference numeral 52a denotes an end of the surface of the base 52 that contacts the elastic member 53 facing the first member 4 on the housing area 6 side, and reference numeral 52b denotes an elastic member facing the first member 4. It represents the end of the surface of the base 52 which contacts 53, on the side remote from the accommodation area 6, ie on the outside. In the example shown in FIG. 15, the end 52 b of the surface of the base 52 outside the base 52 is located closest to the elastic body 53 in the moving direction of the first heat bar 51. Further, of the surface of the elastic body 53, the end 53 a of the elastic body 53 on the accommodation area 6 side is located farthest from the first member 4 in the moving direction of the first heat bar 51. In this case, the end 53 a of the elastic body 53 on the accommodation area 6 side comes into contact with the first member 4 last in the surface of the elastic body 53 facing the first member 4. Preferably, a portion that comes into contact with the first member 4 lastly, such as the end portion 53 a, is a portion of the surface of the base 52 that is closest to the elastic body 53 in the movement direction of the first heat bar 51 (here, the end portion 52b) is located on the first member 4 side. Accordingly, it is possible to suppress the first member 4 from being excessively pressed by the portion of the surface of the base 52 that is closest to the elastic body 53.

  Next, a method of joining the exterior body 3 in the opening region 3b using the second heat sealer 50 will be described. When the first heat bar 51 is moved to the first member 4 side, as shown in FIG. 16, the portion of the first member 4 located on the outer side is more than the portion of the first member 4 located on the accommodation region 6 side. Also contact the elastic body 53 of the first heat bar 51 first, and are heated and pressed. For this reason, the exterior body bonding layer 8 is formed in a portion located on the outside of the first member 4. At this time, the portion of the elastic body 53 that contacts the first member 4 is compressed and deformed in the moving direction of the first heat bar 51 as shown in FIG. The force applied by the first heat bar 51 to the first member 4 increases as the amount of compressive deformation of the elastic body 53 increases.

  FIG. 17 shows a state in which the first heat bar 51 is moved to the first member 4 side until the portion of the first member 4 located on the accommodation area 6 side comes into contact with the elastic body 53 of the first heat bar 51. Is shown. In the state shown in FIG. 17, the elastic body 53 is in contact with the entire region of the first member 4 to be the sealing region 7, and the elastic body 53 is compressed and deformed. The degree of compressive deformation of the elastic body 53 is greater toward the outside. For this reason, the force applied by the first heat bar 51 to the first member 4 is greater toward the outside.

  While the first member 4 is being heated and pressed from the first heat bar 51, the thermoplastic resin layer 4b of the first member 4 and the thermoplastic resin layer 5b of the second member 5 are molten. The thermoplastic resin in a molten state has fluidity. In addition, the force applied by the first heat bar 51 to the first member 4 is greater toward the outside. Therefore, the thermoplastic resin in the molten state receives a force from the outside toward the housing space 6a. Therefore, even if the electrolytic solution 8s adheres to the inner surface of the first member 4 or the inner surface of the second member 5, as shown in FIGS. 16 and 17, the electrolytic solution 8s is moved to the accommodation space 6a side. Can be moved. Therefore, as shown in FIG. 17, it is possible to suppress the electrolytic solution 8s from remaining in at least the outer portion of the exterior body bonding layer 8. Thereby, at least a portion of the exterior body bonding layer 8 where the electrolytic solution 8s does not remain and a portion having sufficient bonding strength can be provided. Thus, it is possible to prevent the housing space 6a of the exterior body 3 from communicating with the outside.

  In the above, one embodiment has been described with reference to a specific example, but the above-described specific example is not intended to limit the embodiment. The above-described embodiment can be carried out in various other specific examples, and various omissions, replacements, and changes can be made without departing from the gist of the embodiment.

  Hereinafter, an example of a modification will be described with reference to the drawings. In the following description and the drawings used in the following description, portions that can be configured in the same manner as in the above-described specific example will be denoted by the same reference numerals as those used for corresponding portions in the above-described specific example, and will be described in duplicate. Is omitted.

(Modification of the first heat sealer)
In the above-described embodiment, the thickness of the exterior body bonding layer 8 in the sealing region 7 formed by the first heat bar 41 of the first heat sealer is set such that the thickness of the sealing region 7 from the outer end of the sealing region 7 decreases. An example is shown in which the density monotonically increases up to the boundary with the accommodation area 6. However, as long as the thickness T1 of the exterior body bonding layer 8 at the boundary between the sealing region 7 and the housing region 6 is larger than the thickness T2 of the exterior body bonding layer 8 at the outer end of the sealing region 7. The configuration of the exterior body bonding layer 8 in the sealing region 7 is not particularly limited. For example, as shown in FIG. 18, in a part of the exterior body bonding layer 8, the thickness of the exterior body bonding layer 8 is directed from the outer end of the sealing area 7 to the boundary between the sealing area 7 and the housing area 6. Accordingly, the thickness of the exterior body bonding layer 8 may be constant in other portions. As shown in FIG. 19, for example, as shown in FIG. 19, a part of the surface of the first heat bar 41 facing the first member 4 is the inclined surface 41a, and the other part is the first member 4 The first member 4 can be formed by pressing the first member 4 using a first heat bar 41 which is a flat surface parallel to the surface direction of the first member 4.

  The inclined surface 41a of the first heat bar 41 shown in FIG. 19 also has a gap between the inclined surface 41a and the first member 4 toward the accommodation area 6 side, similarly to the inclined surface 41a in the above-described embodiment. The first member 4 is inclined with respect to the plane direction so as to increase. Therefore, by pressing the first member 4 using the first heat bar 41 to form the exterior body bonding layer 8, the thickness T1 of the exterior body bonding layer 8 at the boundary between the sealing region 7 and the housing region 6 is reduced. The thickness T2 of the exterior body bonding layer 8 at the outer end of the sealing region 7 can be made larger. In addition, it is possible to form the exterior body resin protruding portion 8a that protrudes toward the housing space 6a from the boundary between the sealing region 7 and the housing region 6.

  Further, in the above-described embodiment and the modification, the thickness of the exterior body bonding layer 8 of the sealing region 7 formed by the first heat bar 41 of the first heat sealer is set to be greater than the outer end of the sealing region 7. An example has been shown in which the density at least partially monotonically increases toward the boundary between the sealing area 7 and the accommodation area 6. However, as long as the thickness T1 of the exterior body bonding layer 8 at the boundary between the sealing region 7 and the housing region 6 is larger than the thickness T2 of the exterior body bonding layer 8 at the outer end of the sealing region 7. The configuration of the exterior body bonding layer 8 in the sealing region 7 is not particularly limited. For example, as shown in FIG. 20, the exterior body bonding layer 8 has a stepped portion 8b, and the thickness of the exterior body bonding layer 8 on the housing area 6 side of the stepped portion 8b is outside the stepped portion 8b. It may be larger than the thickness of the layer 8. As shown in FIG. 21, such an exterior body bonding layer 8 is formed by pressing the first member 4 using a first heat bar 41 having a step portion 41 b formed on a surface facing the first member 4. Can be done.

(Modification of the second heat sealer)
In the above-described embodiment, the inclined surface 51a of the elastic body 53 of the first heat bar 51 of the second heat sealer 50 increases as the distance between the inclined surface 51a and the first member 4 approaches the housing area 6 side. In this case, the first member 4 is inclined with respect to the surface direction. However, the shape of the surface of the elastic body 53 is not particularly limited as long as the surface of the elastic body 53 facing the first member 4 is at least partially inclined.

  For example, as shown in FIG. 22, the inclined surface 51 a of the elastic body 53 of the first heat bar 51 of the second heat sealer 50 increases as the distance between the inclined surface 51 a and the first member 4 approaches the accommodation area 6 side. For example, the first member 4 may be inclined with respect to the surface direction. In this case, the electrolytic solution 8s attached to the inner surface of the first member 4 or the inner surface of the second member 5 can be moved outward from the accommodation space 6a.

  Further, in the above-described embodiment, an example has been described in which the inclined surface 51 a forms the entire surface of the elastic body 53 facing the first member 4. However, the present invention is not limited to this. As shown in FIG. 23, a part of the surface of the elastic body 53 facing the first member 4 is the inclined surface 51a, but the other part of the surface of the elastic body 53 is , May be a flat surface parallel to the surface direction of the first member 4.

  In the above-described embodiment and each of the modifications, the surface of the base 52 that is in contact with the elastic body 53 is inclined with respect to the surface direction of the first member 4, and the thickness of the elastic body 53 does not depend on the position. An example is given that is uniform. However, the present invention is not limited to this. For example, as shown in FIG. 24, the surface of the base 52 in contact with the elastic body 53 may be a flat surface parallel to the surface direction of the first member 4. In this case, as shown in FIG. 24, by changing the thickness of the elastic body 53 according to the position, the surface of the elastic body 53 facing the first member 4 can be the inclined surface 51a.

  Further, in the above-described embodiment and each of the modified examples, the example in which the inclination direction of the elastic body 53 is constant has been described. However, the shape of the surface of the elastic body 53 is not particularly limited as long as the surface of the elastic body 53 facing the first member 4 is at least partially inclined. For example, as shown in FIG. 25, the first elastic member 53 is inclined with respect to the surface direction of the first member 4 such that the distance between the elastic member 53 and the first member 4 increases toward the accommodation region 6 side. And the second inclined surface 51a that is inclined with respect to the surface direction of the first member 4 so that the distance between the first inclined surface 51a and the first member 4 increases outward. May be. In this case, the first inclined surface 51a can move the electrolytic solution 8s attached to the inner surface of the first member 4 or the inner surface of the second member 5 from the outside to the accommodation space 6a. Further, the second inclined surface 51a can move the electrolytic solution 8s attached to the inner surface of the first member 4 or the inner surface of the second member 5 from the accommodation space 6a side to the outside.

  Although some modifications to the above-described embodiment have been described above, it is needless to say that a plurality of modifications may be appropriately combined and applied.

DESCRIPTION OF SYMBOLS 1 Stacked battery 2 Membrane electrode assembly 3 Outer body 4 First member 4a Base material 4b Thermoplastic resin layer 5 Second member 5a Base material 5b Thermoplastic resin layer 6 Housing area 6a Housing space 7 Sealing area 7a First seal Stop region 7b Second sealing region 7c Third sealing region 8 Exterior body bonding layer 8a Exterior body resin protrusion 9 Sealant bonding layer 9a Sealant resin protrusion 10 First electrode plate 10X Positive electrode plate 11 First electrode current collector 11X Positive electrode current collector 11a First surface 11b Second surface 12 First electrode active material layer 12X Positive electrode active material layer 16 First tab 18 First sealant 20 Second electrode plate 20Y Negative plate 21 Second electrode current collector 21Y Negative electrode collector Conductor 21a First surface 21b Second surface 22 Second electrode active material layer 22Y Negative electrode active material layer 26 Second tab 28 Second sealant 30 Insulator 40 First heat sealer 41 First heat bar 41a Inclined surface 41b Step Part 46 The second heat bar 50 second heat sealer 51 first heat bar 51a inclined surface 52 the base portion 53 elastic member 56 second heat bar 57 base 58 elastic body

Claims (11)

A membrane electrode assembly having a first electrode plate and a second electrode plate alternately stacked;
A housing region having a first member and a second member, wherein a housing space defining the membrane electrode assembly is defined between the first member and the second member; An outer package, comprising: a sealing region located on the outer periphery of the region, where the first member and the second member are joined.
The sealing region includes an exterior body bonding layer in which a thermoplastic resin layer forming an inner surface of the first member and a thermoplastic resin layer forming an inner surface of the second member are bonded.
The thickness of the exterior body bonding layer at the boundary between the sealing region and the housing region is larger than the thickness of the exterior body bonding layer at the outer end of the sealing region.
The stacked battery includes the exterior body bonding layer including an exterior body resin protrusion that protrudes toward the housing space from a boundary between the sealing region and the housing region.   2. The stacked battery according to claim 1, wherein at least one side of the exterior body resin layer of the exterior body joining layer extends along the one side on at least one side of the sealing region of the exterior body. 3.   3. The stacked battery according to claim 2, wherein the exterior body resin protrusion of the exterior body joining layer is formed over the entirety of the at least one side of the sealing region of the exterior body.   The thickness of the exterior body bonding layer increases from the outer end of the sealing region toward the boundary between the sealing region and the housing region, according to any one of claims 1 to 3. Stacked battery.   The lamination according to any one of claims 1 to 4, wherein a projecting length of the exterior body resin protrusion of the exterior body joining layer toward the accommodation space is equal to or greater than a thickness of the thermoplastic resin layer. Type battery. The stacked battery further includes a tab connected to the membrane electrode assembly and projecting outward from at least one side of the sealing region of the exterior body,
The stacked battery according to any one of claims 1 to 5, wherein the exterior body resin protrusion of the exterior body joining layer is provided at least on the one side of the sealing region from which the tab projects. . The stacked battery,
A sealant positioned between the first member and the second member to cover the tab from the side of the first member;
A sealant positioned between the first member and the second member to cover the tab from the side of the second member,
The sealing region further includes a sealant bonding layer in which the first member-side sealant and the second member-side sealant are bonded,
The thickness of the sealant bonding layer at the boundary between the sealing region and the housing region is greater than the thickness of the sealant bonding layer at the outer end of the sealing region,
7. The stacked battery according to claim 6, wherein the sealant bonding layer includes a sealant protrusion that protrudes toward the housing space from a boundary between the sealing region and the housing region.   The stacked battery according to claim 7, wherein at least one side of the sealing region of the exterior body, the exterior body resin protrusion and the sealant protrusion are integrally formed. A preparing step of preparing a membrane electrode assembly having a first electrode plate and a second electrode plate alternately stacked;
A housing step of housing the membrane / electrode assembly inside an exterior body having a first member and a second member, wherein the exterior body includes the membrane electrode between the first member and the second member; An accommodation area in which an accommodation space for accommodating the joined body is defined; a sealing area located on the outer periphery of the accommodation area, where the first member and the second member are joined; An opening step, which is located on the outer periphery and includes an opening area where the first member and the second member are not joined,
An electrolyte injection step of injecting an electrolyte into the housing space of the exterior body through the opening region,
A closing step of joining the first member and the second member in the opening region of the exterior body,
The sealing region includes an exterior body bonding layer in which a thermoplastic resin layer forming an inner surface of the first member and a thermoplastic resin layer forming an inner surface of the second member are bonded.
The thickness of the exterior body bonding layer at the boundary between the sealing region and the housing region is larger than the thickness of the exterior body bonding layer at the outer end of the sealing region.
The method for manufacturing a stacked battery, wherein the exterior body joining layer includes an exterior body resin protrusion that protrudes toward the housing space beyond a boundary between the sealing region and the housing region. The closing step includes, using a first heat bar, pressing the first member toward the second member while heating the first member,
The method according to claim 9, wherein the first heat bar includes an elastic body including an inclined surface facing the first member, and a base supporting the elastic body.   The inclined surface of the elastic body, in a state before the first heat bar presses the first member, so that the interval between the inclined surface and the first member increases toward the housing area, The method for manufacturing a stacked battery according to claim 10, wherein the battery is inclined.