JP7235571B2 - Laminated battery manufacturing method - Google Patents

Description

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

For example, as proposed in Japanese Unexamined Patent Application Publication No. 2002-100000, a laminated battery in which positive electrode plates and negative electrode plates are alternately laminated has been widely used. A lithium ion secondary battery can be exemplified as an example of a stacked battery. One of the features of the lithium ion secondary battery is that it has a large capacity compared to other types of stacked batteries. Lithium-ion secondary batteries having such characteristics are expected to spread further in various applications such as on-vehicle applications and stationary housing applications.

In a laminate type battery typified by a lithium ion secondary battery, a membrane electrode assembly having electrode plates 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. there is The periphery of the exterior body is sealed from the outside by a bonding layer formed by melting a thermoplastic resin by pressing the exterior body while heating it.

JP 2017-152140 A

It is conceivable that the bonding strength of the bonding layer is lowered when foreign matter is present on the surface of the film forming the exterior body when the exterior body is bonded.

An object of the present invention is to provide a method for manufacturing a stacked battery that can effectively solve such problems.

A method for manufacturing a stacked type battery according to the present invention includes a preparation step of preparing a membrane electrode assembly having first electrode plates and second electrode plates that are alternately stacked; A housing step of housing inside an exterior body having a rectangular first member and a second member including two sides, a third side, and a fourth side, wherein the exterior body includes the first member and the second member and a housing area defining a housing space for housing the membrane electrode assembly between the membrane electrode assembly and the housing area. 1 sealing region, and an opening region located on the outer periphery of the housing region and where the first member and the second member are not joined, the first sealing region being the a first side sealing region extending along a first side; a second side sealing region extending along the second side of the exterior body; and a second side sealing region extending from the first side sealing region to the second side sealing region. between the third side sealing region extending along the third side of the exterior body and the first side sealing region and the second side sealing region of the fourth side of the exterior body and a fourth side partial sealing region located on a part of the exterior body, wherein the opening region is located between the first side sealing region and the second side sealing region of the fourth side of the exterior body. an electrolytic solution injection step of injecting an electrolytic solution into the accommodation space of the exterior body through the opening area; and and a sealing step of joining the two members to form a second sealing region.

The method for manufacturing a stacked battery according to the present invention further includes an initial charging step of charging the membrane electrode assembly housed inside the exterior body after the electrolyte injection step and before the sealing step. The initial charging step may include a degassing step of removing gas generated by charging the membrane electrode assembly from the housing space through the opening region.

In the method for manufacturing a laminated battery according to the present invention, the opening area is 0.05 of the distance between the first side sealing area and the second side sealing area in the direction in which the fourth side extends. It may have a dimension of 0.3 times or more.

In the method for manufacturing a stacked battery according to the present invention, the opening region may be positioned between the second side sealing region and the fourth side partial sealing region.

In the method for manufacturing a laminated battery according to the present invention, the fourth side partial sealing region has a first portion located on the first side and a second portion located on the second side. , the open area may be located between the first portion and the second portion.

In the method for manufacturing a laminated battery according to the present invention, in the sealing step, the second sealing region is formed so that the thickness of the second sealing region is larger than the thickness of the first sealing region. may be formed.

In the method for manufacturing a laminated battery according to the present invention, the first member and the second member each include a base material and a thermoplastic resin layer positioned closer to the accommodation space than the base material, and the accommodation step is a first exterior body bonding that joins the first member and the second member from the thermoplastic resin layer of the first member and the thermoplastic resin layer of the second member at the outer periphery of the accommodation area A joining step of forming the first sealing region by forming a layer, wherein in the sealing step, the thermoplastic resin layer of the first member and the second member The second sealing region may be formed by forming a second exterior body bonding layer for bonding the first member and the second member from the thermoplastic resin layer of .

In the method for manufacturing a laminated type battery according to the present invention, in the sealing step, the thickness of the second exterior body bonding layer is the thickness of the thermoplastic resin layer of the first member in the opening region before the sealing step. The second sealing region may be formed so as to be 90% or more of the total thickness of the thickness and the thickness of the thermoplastic resin layer of the second member.

In the manufacturing method of the stacked type battery according to the present invention, in the bonding step of the housing step, the thickness of the first exterior body bonding layer is reduced by the heat of the first member in the outer periphery of the housing area before the bonding step. The first sealing region may be formed so as to be less than 90% of the total thickness of the thermoplastic resin layer and the thermoplastic resin layer of the second member.

In the manufacturing method of the laminated type battery according to the present invention, in the sealing step, the first member is heated in the opening region of the outer package using a sealing step first heat bar while the first member is heated. The sealing step first heat bar includes an elastic body including an inclined surface facing the first member, and the and a base that supports the elastic body.

In the method for manufacturing a stacked type battery according to the present invention, the inclined surface of the elastic body may be inclined such that the distance between the inclined surface and the first member increases toward the housing area. .

In the manufacturing method of the stacked type battery according to the present invention, the inclined surface of the elastic body constitutes the entire surface of the elastic body facing the first member and in contact with the first member among the surfaces of the elastic body. You may have

In the method for manufacturing a stacked type battery according to the present invention, a portion of the surface of the elastic body facing the first member, which is located furthest from the first member, is located on the surface of the base supporting the elastic body. Among them, the portion located closest to the first member may be located closer to the first member.

According to the manufacturing method of the laminated type battery of the present invention, it is possible to ensure the bonding strength of the exterior body.

FIG. 1 is a diagram for explaining an embodiment of the present invention, and is a perspective view showing a stacked battery. 2 is a perspective view showing a membrane electrode assembly included in the stacked battery of FIG. 1. FIG. 3 is a plan view showing a membrane electrode assembly included in the stacked battery of FIG. 1. FIG. 4 is a cross-sectional view showing a membrane electrode assembly included in the stacked battery of FIG. 1. FIG. FIG. 5 is a cross-sectional view showing a cross section along line VV of FIG. FIG. 6 is a cross-sectional view showing an example of a cross-section of the sealing region of the exterior body of FIG. 3 along the line VI--VI. FIG. 7 is a cross-sectional view showing an example of a cross section along line VII-VII of the sealing region of the exterior body in FIG. FIG. 8 is a diagram showing a housing step of housing the membrane electrode assembly inside the exterior body. FIG. 9 is a diagram showing a joining step of joining the first member and the second member of the exterior body in the housing step. FIG. 10 is a diagram showing a joining step of joining the first member and the second member of the exterior body in the housing step. FIG. 11 is a diagram showing a state in which the first member and the second member of the exterior body are joined together on the side of the external region in the initial charging step. FIG. 12 is a diagram showing a state in which the housing space of the exterior body is communicated with the outside through the opening region in the initial charging process. FIG. 13 is a diagram showing how the first member and the second member are joined in the opening region of the exterior body in the sealing step. FIG. 14 is a diagram showing an opening region of an exterior body according to a comparative example. FIG. 15 is a diagram showing a modification of the opening region. FIG. 16 is a diagram showing a modification of the opening region. FIG. 17 is a diagram showing a modification of the opening region. FIG. 18 is a diagram showing a modification of the thick portion. FIG. 19 is a diagram showing a first modification of the sealing process. FIG. 20 is a diagram showing a second modification of the sealing process. FIG. 21 is a diagram showing a second modification of the sealing process. FIG. 22 is a diagram showing a second modification of the sealing process.

An embodiment of the present invention will be described below with reference to the drawings. In addition, in the drawings attached to this specification, for the convenience of easy understanding, the scale, the ratio of vertical and horizontal dimensions, etc. are appropriately changed and exaggerated from those of the real thing.

First, a stack-type battery manufactured by an embodiment of the method for manufacturing a stack-type battery according to the present invention will be described. 1 to 7 are diagrams for explaining a stacked battery manufactured by an embodiment of a method for manufacturing a stacked battery according to the present invention. FIG. 1 is a perspective view showing a specific example of a laminated battery. The laminated battery 1 includes a membrane electrode assembly 2, an outer package 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 and . The tabs 16, 26 and the sealants 18, 28 partially extend from the interior of the exterior body 3 to the exterior.

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. FIG. Each component of the stacked battery 1 will be described below.

(Membrane electrode assembly)
The membrane electrode assembly 2 has first electrode plates 10 and second electrode plates 20 that are alternately laminated. In this embodiment, an example in which the membrane electrode assembly 2 constitutes a lithium ion secondary battery will be described. In this example, the first electrode plate 10 constitutes the positive electrode plate 10X, and the second electrode plate 20 constitutes the negative electrode plate 20Y. However, as can be understood from the description of the effects 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 It can be widely applied to the membrane electrode assembly 2 formed by alternately laminating 20 .

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

In the illustrated non-limiting example, the positive plate 10X and the negative plate 20Y have rectangular contours. The positive electrode plate 10X and the negative electrode plate 20Y have a longitudinal direction in a first direction d1 that is orthogonal to the stacking direction dL and the direction in which the tabs 16 and 26 extend, and are orthogonal to both the stacking 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 arranged to be shifted in the first direction d1. More specifically, the plurality of positive plates 10X are arranged closer to one side (upper right side in FIG. 2) in the first direction d1, and the plurality of negative plates 20Y are arranged closer to the other side (upper right in FIG. 2) in the first direction d1. (lower left side of )). The positive electrode plate 10X and the negative electrode plate 20Y overlap each other in the stacking direction dL at the center in the first direction d1.

As illustrated, the positive electrode plate 10X (first electrode plate 10) has a sheet-like outer shape. 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 12X) provided on the positive electrode current collector 11X. 12) and. In the lithium ion secondary battery, the positive electrode plate 10X releases lithium ions during discharging and absorbs lithium ions during charging.

The positive electrode current collector 11X has, as main surfaces, a first surface 11a and a second surface 11b facing each other. The cathode active material layer 12X is formed on at least one of the first surface 11a and the second surface 11b of the cathode 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 is not provided with 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

The positive electrode current collector 11X and the positive electrode active material layer 12X can be produced by various manufacturing methods using various materials that can be applied to the laminated battery 1 (lithium ion secondary battery). As an example, the positive electrode current collector 11X may be made of aluminum foil. The positive electrode active material layer 12X contains, for example, a positive electrode active material, a conductive aid, and a binding agent that serves as a binder. The positive electrode active material layer 12X is produced by applying a positive electrode slurry obtained by dispersing a positive electrode active material, a conductive aid, and a binder in a solvent onto the material forming the positive electrode current collector 11X and solidifying the slurry. can be As the positive electrode active material, for example, a lithium metal oxide compound represented by the 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, and lithium manganate. Acetylene black or the like may be used as the conductive aid. Polyvinylidene fluoride or the like may be used as the binder.

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 arranged only in the first effective region b1 of the positive electrode current collector 11X. The first connection area a1 and the first effective area 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 bonding, or the like. On the other hand, the first effective region b1 is located within a region of the negative electrode plate 20Y facing the negative electrode active material layer 22Y, which will be described later. Such arrangement of the first effective region b1 can prevent deposition of lithium from the positive electrode active material layer 12X.

Next, the negative electrode plate 20Y (second electrode plate 20) will be described. Similarly to the positive plate 10X, the negative plate 20Y also has a sheet-like outer shape. 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) and In the lithium ion secondary battery, the negative electrode plate 20Y absorbs 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. A plurality of negative electrode plates 20Y included in the laminate type battery 1 can be configured identically to each other by 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 produced by various manufacturing methods using various materials that can be applied to the laminated battery 1 (lithium ion secondary battery). As an example, the negative electrode current collector 21Y is made of copper foil, for example. The negative electrode active material layer 22Y contains, for example, a negative electrode active material made of a carbon material and a binder that functions as a binder. The negative electrode active material layer 22Y is formed by dispersing a negative electrode slurry in which a negative electrode active material such as carbon powder or graphite powder and a binder such as polyvinylidene fluoride are dispersed in a solvent to form the negative electrode collector 21Y. It can be made by coating on a material and solidifying it.

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

At least one of the positive electrode plate 10X (first electrode plate 10) and the negative electrode plate 20Y (second electrode plate 20) may have an insulator (insulating layer) 30, as shown in FIG. The insulator 30 prevents a short circuit between the positive electrode plate 10X (first electrode plate 10) and the negative electrode plate 20Y (second electrode plate 20).
In the illustrated example, the negative electrode plate 20Y has an 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 of the insulator 30 . However, instead of the illustrated insulator 30 or in addition to the illustrated insulator 30, it is also possible to install an insulator 30 covering the pair of positive electrode active material layers 12X included in each positive electrode plate 10X.

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

(tab)
The tabs 16 and 26 have 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 cross-sectional view showing a cross section along line VV of FIG. A two-dot chain line shown in FIG. 5 indicates an example of positions of the first member 4 and the second member 5 of the exterior body 3 . As shown in FIG. 5, the first tab 16 is electrically connected to the first electrode plate 10 . Although not shown, the second tab 26 is electrically connected to the second electrode plate 20 . In the example shown in FIG. 5, the first tab 16 is connected to the second surface 11b (lower surface) of the positive electrode plate 10X located on the lowest side in the first connection area a1. Although not shown, the second tab 26 is also connected to the second surface 21b (lower surface) of the negative electrode plate 20Y located on the lowermost side in the second connection area a2. As long as the positive electrode current collector 11X and the first tab 16 can be electrically connected, the first tab 16 may be attached in any manner. Similarly, as long as the negative electrode current collector 21Y and the second tab 26 can be electrically connected, the attachment method of the second tab 26 is arbitrary.

As shown in FIG. 5, the first tab 16 passes between the first member 4 and the second member 5 of the exterior body 3 and extends from the interior of the exterior body 3 to the exterior 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. there is The first tab 16 functions as a positive terminal in the laminated battery 1 , and the second tab 26 functions as a negative terminal in the laminated battery 1 .

The first tab 16 and the second tab 26 may be formed using, for example, aluminum, nickel, copper alloys, nickel-plated copper, or the like. For example, when the positive electrode current collector 11X is made of aluminum foil and the negative electrode current collector 21Y is made of copper foil, aluminum is used to form the first tab 16, and copper alloy is used to form the second tab. 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 materials for the sealants 18 and 28 include polypropylene, modified polypropylene, low-density polypropylene, ionomer, and ethylene/vinyl acetate. The thickness of the sealants 18, 28 is, for example, 0.05 mm or more and may be 0.4 mm or less.

The sealants 18 , 28 have a first sealant 18 positioned between the first tab 16 and the armor 3 and a second sealant 28 positioned between the second tab 26 and the armor 3 . As shown in FIG. 5 , a first sealant 18 is interposed between the outer body 3 and the first tab 16 in the sealing region 7 . Also, although not shown, a second sealant 28 is interposed between the exterior body 3 and the second tab 26 . As a result, the exterior body 3 can be more firmly sealed around the tabs 16 and 26 . In addition, it is possible to prevent a short circuit between the tabs 16 and 26 and the metal foil such as aluminum foil or stainless steel foil included in the outer package 3 .

(Exterior body)
The exterior body 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-like first member 4 positioned above the membrane electrode assembly 2 and a sheet-like second member 5 positioned below the membrane electrode assembly 2 . , has The first member 4 and the second member 5 are joined together along the outer edge so as to surround the membrane electrode assembly 2 in plan view.

In the following description, a region of the exterior body 3 defining a housing space 6a 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. called. A region of the exterior body 3 located on the outer periphery of the housing region 6 and where 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 area 7 is indicated by hatching. The bonding of the first member 4 and the second member 5 is performed by pressing the first member 4 and the second member 5 while heating to melt the thermoplastic resin contained in the first member 4 and the second member 5. Realized by heat sealing.

As shown in FIG. 3, the first member 4 and the second member 5 of the exterior body 3 have a first side 3c, a second side 3d opposite to the first side 3c, and a first side 3c extending in plan view. It has a rectangular shape including a third side 3e and a fourth side 3f extending in a direction different from the direction. In the example shown in FIG. 3, the first side 3c and the second side 3d extend along the second direction d2. Also, the third side 3e and the fourth side 3f extend along the first direction d1. Moreover, the tabs 16 and 26 pass between the first member 4 and the second member 5 at the first side 3c or the second side 3d and extend to the outside of the exterior body 3 . In the example shown in FIG. 3, the tab 16 extends to the outside of the exterior body 3 through between the first member 4 and the second member 5 on the first side 3c. A tab 26 extends to the outside of the exterior body 3 through between the first member 4 and the second member 5 on the second side 3d. Moreover, the tabs 16 and 26 do not extend from the third side 3e and the fourth side 3f. In this case, the sealing region 7 of the exterior body 3 includes portions extending along each of the first side 3c, the second side 3d, the third side 3e, and the fourth side 3f of the exterior body 3. As shown in FIG. Here, in the present embodiment, a portion of the sealing region 7 extending along the first side 3c of the exterior body 3 is referred to as a first side sealing region 73. As shown in FIG. A portion of the sealing region 7 extending along the second side 3 d of the exterior body 3 is referred to as a second side sealing region 74 . The first side sealing region 73 and the second side sealing region 74 extend from the third side 3e to the fourth side 3f of the exterior body 3, respectively. Further, of the sealing region 7, a portion extending along the third side 3e of the exterior body 3 and extending from the first side sealing region 73 to the second side sealing region 74 is referred to as the third side sealing region. This is referred to as edge sealing region 75 . Further, of the sealing region 7, the portion extending along the fourth side 3f of the exterior body 3 and extending from the first side sealing region 73 to the second side sealing region 74 is referred to as the fourth side sealing region. Referred to as side sealing region 76 . As shown in FIG. 3, the third side sealing region 75 and the fourth side sealing region 76 extend from the position of the inner edge 3h of the first side sealing region 73 of the exterior body 3 to the second side sealing region 74, respectively. It extends to the position of the inner edge 3h.

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 of the sealing region 7 of the exterior body 3 of FIG. 3 along line VI-VI. FIG. 7 is a cross-sectional view showing an example of a cross section of the sealing region 7 of the exterior body 3 of FIG. 3 along line VII--VII.

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 positioned closer to the housing space 6a than the base material 4a. Similarly, the second member 5 includes a base material 5a and a thermoplastic resin layer 5b positioned closer to the housing space 6a than the base material 5a.

The base materials 4a and 5a are provided with 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 metal foil include aluminum foil and 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 71 are melted by being heated to form a bonding layer indicated by reference numeral 8. there is Examples of thermoplastic resins include polypropylene, modified polypropylene, low-density polypropylene, ionomer, and ethylene/vinyl acetate. In the following description, the bonding layer formed by melting the thermoplastic resin layers 4b and 5b is also referred to as an exterior body bonding layer 8. As shown in FIG.

As shown in FIGS. 3 and 7, the fourth side sealing region 76 includes the first flat portion 7b located on the first side 3c side and the second side 3d side of the first flat portion 7b. 2 flat portion 7c. In the example shown in FIG. 3, the first side sealing region 73, the second side sealing region 74 and the third side sealing region 75 also have flat portions. The flat portions of the first side sealing region 73, the second side sealing region 74, and the third side sealing region 75 are hereinafter referred to as outer peripheral flat portions 7e. The flat outer peripheral portion 7 e located on the left side of FIG. 7 is the flat outer peripheral portion 7 e of the second side sealing region 74 . In the present embodiment, as will be described later, the first flat portion 7b and the outer peripheral flat portion 7e are first formed, then the electrolytic solution is injected into the exterior body 3, and then the second flat portion 7c is formed. It is formed.

As shown in FIG. 7, the fourth side sealing region 76 is positioned between the first flat portion 7b and the second flat portion 7c and has a thickness greater than that of the first flat portion 7b and the second flat portion 7c. It has a portion 7a. Also, the fourth side sealing region 76 may have the thick portion 7a at a position other than between the first flat portion 7b and the second flat portion 7c. In the example shown in FIG. 7, of the two thick portions 7a shown in the figure, the right thick portion 7a is located between the first flat portion 7b and the second flat portion 7c. 7 is located closer to the second side 3d than the second flat portion 7c, and is in contact with a portion of the sealing region 7 extending along the second side 3d. The thick portion 7a positioned between the first flat portion 7b and the second flat portion 7c is also referred to as a first thick portion 7a1. Further, the thick portion 7a located at a position other than between the first flat portion 7b and the second flat portion 7c is also referred to as a second thick portion 7a2.

As shown in FIG. 7, the thick portion 7a has an exterior body bonding layer 8 that is thicker than the first flat portion 7b and the second flat portion 7c. It has thicknesses t3 and t4 that are greater than the thickness t2 of the flat portion 7c. In the example shown in FIG. 7, the thickness of the substrates 4a and 5a in the thick portion 7a is the same as the thickness of the substrates 4a and 5a in the first flat portion 7b and the second flat portion 7c. In the case shown in FIG. 7, the thickness t7 of the exterior body bonding layer 8 at the first thick portion 7a1 is, for example, the thickness t5 of the exterior body bonding layer 8 at the first flat portion 7b and the thickness t5 of the exterior body bonding layer 8 at the second flat portion 7c. It is 2.5 times or more and 4.5 times or less of the thickness t6 of 8. The thickness t7 of the exterior bonding layer 8 at the first thick portion 7a1 is greater than the thickness t5 of the exterior bonding layer 8 at the first flat portion 7b and the thickness t6 of the exterior bonding layer 8 at the second flat portion 7c. It may be larger by 0.3 mm or more and 0.5 mm or less. Also, the thickness t8 of the exterior body bonding layer 8 at the second thick portion 7a2 is, for example, 2.5 times or more and 4.5 times or less the thickness t6 of the exterior body bonding layer 8 at the second flat portion 7c. Also, the thickness t8 of the exterior body bonding layer 8 at the second thick portion 7a2 may be greater than the thickness t6 of the exterior body bonding layer 8 at the second flat portion 7c by 0.3 mm or more and 0.5 mm or less.

The thickness t3 of the first thick portion 7a1 and the thickness t4 of the second thick portion 7a2 may be the same or different. When the thickness t3 of the first thick portion 7a1 and the thickness t4 of the second thick portion 7a2 are different, the thickness t3 of the first thick portion 7a1 may be larger than the thickness t4 of the second thick portion 7a2.

The distance w1 between the first thick portion 7a1 and the second thick portion 7a2 shown in FIG. 7 is, for example, the distance between the first side sealing region 73 and the second side sealing region 74 shown in FIG. It is 0.05 times or more and 0.3 times or less of w2.

Next, a method for manufacturing the laminated battery 1 according to the present embodiment configured as a lithium ion secondary battery will be described. The manufacturing method of the laminated type battery described below includes a membrane electrode assembly preparation step of preparing the membrane electrode assembly 2, and the first tab 16 and the second tab 26 are connected to the first connection region a1 of the positive electrode current collector 11X and A step of attaching a tab to the second connection region a2 of the negative electrode current collector 21Y, a step of accommodating the membrane electrode assembly 2 inside the exterior body 3, A sealing step of joining the first member 4 and the second member 5 in the opening region of the exterior body 3 is provided. The method for manufacturing the laminated battery 1 may further include an initial charging step of initially charging the membrane electrode assembly after the electrolyte injection step and before the sealing step. Each step will be described below.

(Membrane electrode assembly preparation step)
In the membrane electrode assembly preparation step, the membrane electrode assembly 2 having the first electrode plates 10 and the second electrode plates 20 alternately laminated is prepared. The membrane electrode assembly preparation process includes a process of manufacturing the positive electrode plate 10X (first electrode plate 10) and the negative electrode plate 20Y (second electrode plate 20), respectively, and a process of manufacturing the positive electrode plate 10X (first electrode plate 10) and the negative electrode plate 20Y. and a step of alternately stacking (the second electrode plates 20).

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

The positive electrode plate 10X is formed by, for example, coating and solidifying a composition (slurry) that will constitute the positive electrode active material layer 12X on a long aluminum foil that will constitute the positive electrode current collector 11X, Next, it can be produced by cutting to a desired size. Similarly, the negative electrode plate 20Y is produced, for example, by applying a composition (slurry) that forms the negative electrode active material layer 22Y onto a long copper foil that forms the negative electrode current collector 21Y. It can be made by solidifying and then cutting to the desired size. In the case where the insulator 30 functioning as the electrolyte layer 30A is applied to at least one of the positive electrode plate 10X and the negative electrode plate 20Y, the long material before cutting to form the electrode plates 10 and 20 or after cutting The insulator 30 can be produced by applying an electrolytic solution onto the sheet material and solidifying or gelling the 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 laminated such that the positive electrode active material layer 12X of the positive electrode plate 10X and the negative electrode active material layer 22Y of the negative electrode plate 20Y face each other. Next, the first connection regions a1 of the plurality of positive electrode current collectors 11X are joined together by resistance welding, ultrasonic welding, or the like. The same applies to the plurality of negative electrode current collectors 21Y. In this manner, a membrane electrode assembly 2 in which a plurality of positive electrode plates 10X and a plurality of negative electrode plates 20Y are alternately laminated can be obtained.

(Tab mounting process)
In the tab attachment process, 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 tab 16 so that the first sealant 18 faces the first connection region a1 of the positive electrode current collector 11X in the first direction d1. After 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. This allows the first tab 16 to 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 to electrically connect the second tab 26 to the negative electrode current collector 21Y.

(Accommodation process)
In the housing step, the membrane electrode assembly 2 is placed in rectangular first and second members 4 and 5 each having a first side 3c, a second side 3d, a third side 3e and a fourth side 3f by the following method. is accommodated inside the exterior body 3 having First, an arrangement step of arranging the membrane electrode assembly 2 between the first member 4 and the second member 5 is performed. Subsequently, a joining step of joining the first member 4 and the second member 5 by heat welding is performed on the entire first side 3c, the second side 3d, the third side 3e, and a part of the fourth side 3f. . Thus, the exterior body 3 in which the membrane electrode assembly 2 is housed can be obtained.

An example of the accommodation process will be described. FIG. 8 is a diagram showing an example of how the membrane electrode assembly 2 is housed inside the exterior body 3 by performing the housing step. A straight line L1 indicated by a broken line and a solid line in FIG. 8 indicates a position where the fourth side 3f is to be formed in the laminated battery 1 manufactured according to the present embodiment. In the following description, this straight line L1 will be referred to as a fourth side formation scheduled line L1. In this case, the planned fourth side formation line L1 can be regarded as the fourth side 3f. In the example shown in FIG. 8 , the outer package 3 includes not only the housing region 6 and the sealing region 7 of the manufactured laminated battery 1, but also the housing region 6 when viewed from the planned fourth side formation line L1 of the laminated battery 1. It has an outer region 9 extending on the side opposite to the side on which it is located. In addition, the exterior body 3 has an external region side 3g facing the third side 3e. In this case, first, in the arranging step, the membrane electrode assembly 2 to which the first tab 16 and the second tab 26 are attached is arranged between the regions corresponding to the housing regions 6 of the first member 4 and the second member 5. . Subsequently, in the joining step, the first member 4 and the second member 5 are joined together at the outer circumference of the housing area 6 . In the present embodiment, as shown in FIG. 8, in a state in which the first tab 16 and the second tab 26 are extended to the outside, the entire area of the first side 3c, the second side 3d and the third side 3e is , the first member 4 and the second member 5 are joined by heat welding. Further, the first member 4 and the second member 5 are thermally welded along a part of the fourth side formation planned line L1 on the side where the membrane electrode assembly 2 is arranged when viewed from the fourth side formation planned line L1. joined by Also, in the external region 9, the first member 4 and the second member 5 are joined by thermal welding along the extension lines of the first side 3c and the second side 3d. As a result, as shown in FIG. 8, from the thermoplastic resin layer 4b of the first member 4 and the thermoplastic resin layer 5b of the second member 5, the outer body bonding layer for bonding the first member 4 and the second member 5 is formed. 8 can be formed. In the example shown in FIG. 8, the exterior body bonding layer 8 includes a first exterior body bonding layer 8a that bonds the first member 4 and the second member 5 in the outer periphery of the housing area 6, and a first side 3c in the exterior area 9. and an external exterior body bonding layer 8c that bonds the first member 4 and the second member 5 along an extension line of the second side 3d. As a result, a first sealing region 71 located on the outer periphery of the housing region 6 and where the first member 4 and the second member 5 are joined is provided, and the housing region 6 surrounded by the first sealing region 71 is An exterior body 3 in which the membrane electrode assembly 2 is housed in the housing space 6a can be obtained. In the example shown in FIG. 8 , the first sealing region 71 includes a first side sealing region 73 extending along the first side 3c of the exterior body 3 and a second side sealing region 73 extending along the second side 3d of the exterior body 3 . a side sealing region 74; a third side sealing region 75 extending along the third side 3e of the exterior body 3 from the first side sealing region 73 to the second side sealing region 74; and a fourth side partial sealing region 76a located in a part between the first side sealing region 73 and the second side sealing region 74 on the planned side formation line L1. In addition, the first member 4 and the second member 5 are joined in a part between the first side sealing region 73 and the second side sealing region 74 on the fourth side formation planned line L1 of the exterior body 3. The opening region 3b is formed by the opening region 3b. In the example shown in FIG. 8, the opening region 3b is located between the second side sealing region 74 and the fourth side partial sealing region 76a.

The dimension w3 of the opening region 3b in the direction in which the fourth side 3f extends shown in FIG. 8 is, for example, 0.05 times or more the distance w2 between the first side sealing region 73 and the second side sealing region 74. 0.3 times or less.

An example of the joining process in the accommodation process will be described in detail with reference to FIGS. 9 to 11. FIG. 9, the portion along the line IX-IX in FIG. 8, that is, the portion where the first sealing region 71 is formed along the planned fourth side formation line L1 is subjected to the bonding step. FIG. 4 is a diagram showing a method of forming a

First, the bonding process heat sealer 50 used for carrying out the bonding process of the housing process will be described with reference to FIG. In the example shown in FIG. 9 , a bonding process heat sealer 50 supports a bonding process first heat bar 51 that presses the first member 4 toward the second member 5 while heating the first member 4 and supports the second member 5 . and a bonding step second heat bar. The joining process first heat bar 51 moves along the thickness direction of the first member 4 and presses the first member 4 . Although not shown, the bonding process second heat bar 56 may press the second member 5 toward the first member 4 while heating the second member 5, similarly to the bonding process first heat bar 51. .

As shown in FIG. 9, the bonding process first heat bar 51 and the bonding process second heat bar 56 have pressing surfaces having a shape corresponding to the shape of the first sealing region 71 to be formed. In the example shown in FIG. 9, the bonding process first heat bar 51 has two first pressing surfaces 51a, and a space is provided between the two first pressing surfaces 51a. In addition, the bonding process second heat bar 56 has two second pressing surfaces 56a at positions facing the two first pressing surfaces 51a of the bonding process first heat bar 51, and between the two second pressing surfaces 56a. are spaced similarly to the two first pressing surfaces 51a. In the example shown in FIG. 9 , the first pressing surface 51 a is a surface parallel to the outer surface of the first member 4 , and the second pressing surface 56 a is a surface parallel to the outer surface of the second member 5 .

Next, a method of forming the first sealing region 71 using the bonding process heat sealer 50 in the bonding process will be described. The bonding process first heat bar 51 is moved toward the first member 4, and the first pressing surface 51a of the bonding process first heat bar 51 is used to press the first member 4, as shown in FIG. As a result, the portions of the thermoplastic resin layers 4b and 5b of the first member 4 and the second member 5 that overlap the first pressing surface 51a in the thickness direction are melted to form the exterior body bonding layer 8, A first sealing region 71 is formed. As shown in FIG. 10, in the first sealing region 71, a flat first flat portion 7b and an outer peripheral flat portion 7e are formed.

By the way, in the bonding process, the heat from the first pressing surface 51a is also transmitted to the portions of the thermoplastic resin layers 4b and 5b that are not pressed by the first pressing surface 51a of the first heat bar 51 in the bonding process in the thickness direction. May partially melt. For example, a portion of the thermoplastic resin layers 4b and 5b located near the boundary between the portion pressed by the first pressing surface 51a and the portion not pressed may be melted. A thermoplastic resin in a molten state has fluidity. In this case, the molten thermoplastic resin is extruded from the portion pressed by the first pressing surface 51a toward the portion not pressed. That is, the molten thermoplastic resin is extruded from the area where the first sealing area 71 is formed to the area where the first sealing area 71 is not formed. In this way, as shown in FIG. 10, from the boundary between the region where the first sealing region 71 is formed and the region where the first sealing region 71 is not formed, the region side where the first sealing region 71 is not formed is formed. , a thick portion 7a is formed. Although not shown, the thick portion 7a may not be formed in the joining step. In this case, the thick portion 7a may be formed in a sealing step, which will be described later.

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

(Initial charging process)
In the initial charging step, charging of the membrane electrode assembly 2 housed inside the exterior body 3 is performed via the first tab 16 and the second tab 26 . In the initial charging step, first, as shown in FIG. 11, the first member 4 and the second member 5 are joined by thermal welding at the outer region side 3g. The method of joining the first member 4 and the second member 5 at the outer region side 3g is the same as the method of joining the first member 4 and the second member 5 in the joining step of the accommodation step, for example. As a result, the space including the housing space 6a inside the exterior body 3 is sealed.

Next, a power source for charging is prepared, and the positive electrode of the power source is electrically connected to the first tab 16, and the negative electrode of the power source is electrically connected to the second tab 26, respectively. Next, a power source is used to apply current to the laminated battery 1 . Thus, the stacked battery 1 is initially charged. By charging the membrane electrode assembly 2 , gas is generated in the space including the housing space 6 a inside the exterior body 3 .

Next, a degassing step is performed in which the generated gas is removed from the housing space 6a through the opening region 3b. In the degassing step, the exterior body 3 is cut along the planned fourth side formation line L1. As a result, as shown in FIG. 12, the housing space 6a is communicated with the outside through the opening region 3b, and the gas generated by the initial charging can be discharged from the housing space 6a. A fourth side 3f is formed in the exterior body 3 by cutting the exterior body 3 along the fourth side formation planned line L1.

(sealing process)
In the sealing step, as shown in FIG. 13, the first member 4 and the second member 5 are joined by heat welding in the opening region 3b to form the second sealing region 72. As shown in FIG.

First, the sealing process heat sealer 60 used for carrying out the sealing process will be described with reference to FIG. 13 . As shown in FIG. 13 , the sealing process heat sealer 60 has a sealing process first heat bar 61 and a sealing process second heat bar 66 . The sealing process heat sealer 60 has, for example, a shape that allows the first pressing surface 61a of the sealing process first heat bar 61 and the second pressing surface 66a of the sealing process second heat bar 66 to press the range of the opening region 3b. Other than that, it is the same as the bonding step heat sealer 50 . The dimension w4 in the d1 direction of the first pressing surface 61a of the sealing process first heat bar 61 and the second pressing surface 66a of the sealing process second heat bar 66 shown in FIG. It is smaller than the distance between the portion 7a1 and the second thick portion 7a2. As a result, at a position between the first thick portion 7a1 and the second thick portion 7a2, the first pressing surface 61a can be pushed forward without being obstructed by the first thick portion 7a1 or the second thick portion 7a2. It can be brought into contact with the first member 4 and the second pressing surface 66 a can be brought into contact with the second member 5 . Therefore, the first member 4 and the second member 5 can be joined by pressing the first member 4 at a position between the first thick portion 7a1 and the second thick portion 7a2.

The method of joining the first member 4 and the second member 5 in the opening region 3b using the sealing process heat sealer 60 is, for example, using the joining process heat sealer 50 in the joining process of the housing process. It is the same as the method of joining the second member 5 . As a result, as shown in FIGS. 3 and 7, the first member 4 and the second member 5 are separated from the thermoplastic resin layer 4b of the first member 4 and the thermoplastic resin layer 5b of the second member 5 in the opening region 3b. The second sealing region 72 can be formed by forming the exterior body bonding layer 8 that bonds the . Hereinafter, the exterior body bonding layer 8 that joins the first member 4 and the second member 5 in the opening region 3b shown in FIGS. 3 and 7 is also referred to as a second exterior body bonding layer 8b. In this manner, the stacked battery 1 including the membrane electrode assembly 2 sealed inside the outer package 3 with the opening region 3b closed can be produced.

By the way, while the first member 4 is being heated and pressed from the first pressing surface 61a of the sealing step first heat bar 61, the thermoplastic resin layer 4b of the first member 4 and the thermoplastic resin layer 5b of the second member 5 is melting. A thermoplastic resin in a molten state has fluidity. Therefore, the molten thermoplastic resin receives a force directed from the portion pressed by the first pressing surface 61a toward the portion not pressed. As a result, the molten thermoplastic resin is pushed out from the side of the area pressed by the first pressing surface 61a toward the thick portion 7a. Thus, as shown in FIGS. 7 and 13, the dimension of the thick portion 7a formed in the bonding step in the direction in which the fourth side 3f extends and the dimension in the thickness direction of the exterior body 3 are the same as those in the sealing step. may be larger in Although not shown, if the thick portion 7a is not formed in the bonding step, the molten thermoplastic resin is pushed out from the region pressed by the first pressing surface 61a in the sealing step. The thick portion 7a may be formed by In addition, as shown in FIGS. 7 and 13, a flat second flat portion 7c is formed in a region of the second sealing region 72 that is pressed by the first pressing surface 61a.

Advantages brought about by the manufacturing method of the laminated battery 1 according to the present embodiment will be specifically described by comparing with a comparative example.

[Comparative example]
As a comparative example, in the housing step, the entire portion of the planned fourth side formation line L1 of the exterior body 3 between the first side sealing region 73 and the second side sealing region 74 is used as the opening region 3b. Consider the case where the membrane electrode assembly 2 is accommodated in the body 3 . FIG. 13 shows that, in the joining step of the housing step, the entire portion of the planned fourth side formation line L1 of the exterior body 3 between the first side sealing region 73 and the second side sealing region 74 is covered with the opening region 3b. FIG. 2 is a diagram showing a state in which a membrane electrode assembly 2 is accommodated in an exterior body 3 having a shape as shown in FIG. In this case, when the electrolytic solution is injected through the opening region 3b, the electrolytic solution fills the entire portion between the first side sealing region 73 and the second side sealing region 74 of the fourth side formation planned line L1. It could stick. Therefore, the bonding between the first member 4 and the second member 5 in the entire portion between the first side sealing region 73 and the second side sealing region 74 of the fourth side 3f is inhibited by the electrolytic solution. could have been.

On the other hand, the opening region 3b of the exterior body 3 according to the present embodiment is formed between the first side sealing region 73 and the second side sealing region 74 of the fourth side formation planned line L1 or the fourth side 3f. located partly between Then, in the method of manufacturing the stacked battery according to the present embodiment, the electrolytic solution is supplied through this opening region 3b. Therefore, of the regions where the first member 4 and the second member 5 are joined, the region where the electrolytic solution may adhere can be limited to a part of the fourth side 3f. Thereby, the bonding strength between the first member 4 and the second member 5 can be increased, and the defect rate of the stack type battery 1 can be reduced.

Although one embodiment has been described above with reference to specific examples, the above-described specific examples are not intended to limit one embodiment. The embodiment described above can be implemented in various other specific examples, and various omissions, replacements, and modifications can be made without departing from the spirit of the embodiment.

An example of modification will be described below with reference to the drawings. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding portions in the above-described specific example are used for the portions that can be configured in the same manner as in the above-described specific example, and redundant description is given. omitted.

(Modified example of opening area)
In the above embodiment, the opening region 3b is positioned between the second side sealing region 74 of the first sealing region 71 and the fourth side partial sealing region 76a of the first sealing region 71. I gave an example. However, the position of the opening region 3b is not limited to this. In the example shown in FIG. 15, the fourth side partial sealing region 76a of the first sealing region 71 of the first sealing region 71 has a first portion 711 located on the first side 3c side and a second side 3d side. and a second portion 712 located at . In this case, the opening region 3b is positioned between the first portion 711 and the second portion 712, as shown in FIG.

In the accommodating step, when the membrane electrode assembly 2 is accommodated inside the exterior body 3 having the opening region 3b according to this modified example, and the electrolytic solution injection step and the sealing step are performed, the stacked battery 1 shown in FIG. can be obtained. In the example shown in FIG. 16, the portion of the sealing region 7 located on the fourth side 3f includes the first flat portion 7b and the second flat portion 7c, and is closer to the second side 3d than the second flat portion 7c. It further has a third flat portion 7d located at . FIG. 17 is a cross-sectional view showing an example of a cross section of the sealing region 7 of the exterior body 3 of FIG. 16 along line XVII-XVII. In the example shown in FIG. 17, the second thick portion 7a2 is located between the second flat portion 7c and the third flat portion 7d. The thickness t4 of the second thick portion 7a2 is greater than the thickness t9 of the third flat portion 7d. In this case, the thickness t8 of the exterior body bonding layer 8 at the second thick portion 7a2 is, for example, 2.5 times or more and 4.5 times or less the thickness t10 of the exterior body bonding layer 8 at the third flat portion 7d. Also, the thickness t8 of the exterior body bonding layer 8 at the second thick portion 7a2 may be greater than the thickness t10 of the exterior body bonding layer 8 at the third flat portion 7d by 0.3 mm or more and 0.5 mm or less.

(Modified example of thick part)
In the above embodiment and modified example, the fourth side sealing region 76 of the sealing region 7 has the first thick portion 7a1 and the second thick portion 7a2. However, the form of the thick portion 7a is not limited to this. For example, as shown in FIG. 18, the fourth side sealing region 76 of the sealing region 7 may not have the second thick portion 7a2. In this case, the first flat portion 7 b may extend to a first side sealing region 73 of the sealing region 7 and the second flat portion 7 c may extend to a second side sealing region 74 of the sealing region 7 . As shown in FIG. 18, the second flat portion 7c in this modified example spreads out so as to be in contact with the outer peripheral flat portion 7e of the second side sealing region 74 of the sealing region 7 . Also, although not shown, the first flat portion 7b in this modification extends so as to come into contact with the outer peripheral flat portion 7e of the first side sealing region 73 of the sealing region 7 .

In this case, the distance w5 between the first thick portion 7a1 and the second side sealing region 74 of the sealing region 7 shown in FIG. 0.05 times or more and 0.3 times or less of the distance between 7 and the second side sealing region 74 .

(First Modification of Sealing Step)
In the above-described embodiment and each modified example, the method of joining the first member 4 and the second member 5 in the sealing step is the method of joining the first member 4 and the second member 5 in the joining step of the housing step. An example has been described that is similar to how to However, the mode of the sealing process is not limited to this. For example, the bonding strength between the first member 4 and the second member 5 in the second sealing region 72 formed in the opening region 3b is the entire area of the first side 3c, the second side 3d and the third side 3e and the fourth side. A method of joining the first member 4 and the second member 5 in the sealing step may be selected so that the joining strength is smaller than that in the first sealing region 71 formed in a part of the side 3f. For example, the temperature of the sealing process first heat bar 61 and the sealing process second heat bar 66 in the sealing process is made lower than the temperature of the bonding process first heat bar 51 and the bonding process second heat bar 56 in the bonding process of the housing process. Thereby, the bonding strength in the second sealing region 72 can be made smaller than the bonding strength in the first sealing region 71 . In this case, for example, when the pressure in the housing space 6a of the exterior body 3 increases due to the generation of gas, the first member joined in the first sealing region 71 and the second sealing region 72 4 and the second member 5 are preferentially separated in a second sealing area 72 that is limited to a narrower area than the first sealing area 71 . Thereby, an opening is formed in the second sealing area 72, and the pressure in the accommodation space 6a can be lowered. Therefore, it is possible to suppress separation of the first member 4 and the second member 5 in a wide range including the first sealing region 71 .

In the sealing step, when the first member 4 and the second member 5 are joined such that the joint strength in the second sealing region 72 is smaller than the joint strength in the first sealing region 71, for example, Thus, in the sealing step, the second sealing region 72 is formed such that the thickness t2 of the second sealing region 72 is greater than the thicknesses t1 and t11 of the first sealing region 71 . The thickness of the first sealing region 71 means, for example, the maximum thickness among the thicknesses of the flat portions located in the first sealing region 71 . Further, the thickness of the second sealing region 72 means, for example, the maximum thickness among the thicknesses of the flat portions located in the second sealing region 72 . In this case, in the sealing process, for example, the thickness t6 of the second exterior body bonding layer 8b is the thickness of the thermoplastic resin layer 4b of the first member 4 in the opening region 3b before the sealing process and the heat resistance of the second member 5. The second sealing region 72 is formed so as to be 90% or more of the total thickness of the plastic resin layer 5b. In addition, in the bonding step of the housing step, for example, the thicknesses t5 and t12 of the first exterior body bonding layer 8a are the same as the thickness of the thermoplastic resin layer 4b of the first member 4 at the outer periphery of the housing region 6 before the bonding step and the second thickness. The first sealing region 71 is formed so as to be less than 90% of the total thickness of the thermoplastic resin layer 5 b of the member 5 . The thickness of the first exterior body bonding layer 8a means, for example, the maximum thickness of the thicknesses of the exterior body bonding layer 8 in the flat portion located in the first sealing region 71 . Further, the thickness of the second exterior body bonding layer 8b means, for example, the maximum thickness among the thicknesses of the exterior body bonding layer 8 in the flat portion located in the second sealing region 72 . In this case, the thickness t6 of the second exterior body bonding layer 8b is the thickness of the thermoplastic resin layer 4b of the first member 4 and the thickness of the second member 5 in the accommodation area 6, that is, the area where the exterior body bonding layer 8 is not formed. It is 90% or more of the total thickness including the thickness of the thermoplastic resin layer 5b. Further, the thicknesses t5 and t12 of the first exterior body bonding layer 8a are the sum of the thickness of the thermoplastic resin layer 4b of the first member 4 and the thickness of the thermoplastic resin layer 5b of the second member 5 in the housing area 6. of less than 90%. Hereinafter, the sum of the thickness of the thermoplastic resin layer 4b of the first member 4 and the thickness of the thermoplastic resin layer 5b of the second member 5 in the housing area 6 is also referred to as a reference thickness.

In the above case, as shown in FIG. 19, the thickness t2 of the second flat portion 7c formed in the sealing step in the fourth side sealing region 76 of the sealing region 7 is formed in the bonding step of the housing step. is larger than the thickness t1 of the first flat portion 7b. Further, as shown in FIG. 19, the thickness t2 of the second flat portion 7c is the first side sealing region 73, the second side sealing region 74 and It is larger than the thickness of the third side sealing region 75 . The thicknesses of the first side sealing region 73, the second side sealing region 74, and the third side sealing region 75 are, for example, the thicknesses of the first side sealing region 73, the second side sealing region 74, or the thickness of the third side sealing region It means the maximum thickness among the thicknesses of the flat portions located in the sealing region 75 . In this case, the thickness t6 of the exterior body bonding layer 8 at the second flat portion 7c shown in FIG. 19 is, for example, 90% or more of the reference thickness. Moreover, the thickness t5 of the exterior body bonding layer 8 in the first flat portion 7b shown in FIG. 19 is, for example, less than 90% of the reference thickness. Also, the thickness of the exterior body bonding layer 8 in the first side sealing region 73, the second side sealing region 74, and the third side sealing region 75 is, for example, less than 90% of the reference thickness. The thickness of the exterior body bonding layer 8 in the first side sealing region 73, the second side sealing region 74, and the third side sealing region 75 of the sealing region 7 is, for example, the thickness of the first side sealing region 73 , the maximum thickness among the thicknesses of the exterior body bonding layer 8 in the flat portion located in the second side sealing region 74 or the third side sealing region 75 . The thickness t12 of the exterior body bonding layer 8 at the outer peripheral flat portions 7e of the first side sealing region 73, the second side sealing region 74, and the third side sealing region 75 of the sealing region 7 shown in FIG. Less than 90% of the reference thickness. A thickness t6 shown in FIG. 19 is, for example, 100% or less of the reference thickness. Thicknesses t5 and t12 shown in FIG. 19 are, for example, 30% or more of the reference thickness.

(Second Modification of Sealing Step)
In the above-described electrolytic solution injection step, the electrolytic 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 while the electrolytic solution is adhered, a portion where the exterior body bonding layer 8 is not formed is generated in the second sealing region 72, or the second sealing region 72 is not formed. It is conceivable that the bonding strength of the exterior body bonding layer 8 is lowered.

Considering such a problem, the sealing process may be performed so as to remove the electrolytic solution adhering to the inner surface of the first member 4 or the inner surface of the second member 5 . A second modified example of the sealing step, which is carried out so as to remove the electrolytic solution adhering to the inner surface of the first member 4 or the inner surface of the second member 5, will be described in detail below. First, the sealing process heat sealer 60 used for carrying out the sealing process will be described with reference to FIG.

As shown in FIG. 20 , the sealing process heat sealer 60 includes a sealing process first heat bar 61 that presses the first member 4 toward the second member 5 while heating the first member 4 , and the second member 5 . and a sealing step second heat bar 66 that supports the . The sealing step first heat bar 61 moves along the thickness direction of the first member 4 and presses the first member 4 . Similarly to the sealing process first heat bar 61 , the sealing process second heat bar 66 may press the second member 5 toward the first member 4 while heating the second member 5 .

As shown in FIG. 20 , the sealing process first heat bar 61 has an elastic body 63 including an inclined first pressing surface 61 a facing the first member 4 , and a base 62 supporting the elastic body 63 . Hereinafter, the inclined first pressing surface 61a of the elastic body 63 is also referred to as an inclined surface 61b. The elastic body 63 is a member having an elastic modulus lower than that of the base 62 . Although not shown, the sealing process second heat bar 66 may also have an elastic body facing the second member 5 and a base supporting the elastic body, similarly to the sealing process first heat bar 61. good.

The inclined surface 61b of the elastic body 63 is inclined with respect to the surface direction of the first member 4 so that the distance between the inclined surface 61b and the first member 4 increases toward the housing area 6 side. The inclination angle of the inclined surface 61b of the elastic body 63 with respect to the surface direction of the first member 4 is, for example, 0.2° or more and 2° or less.

In FIG. 20, reference numeral 63a denotes the end portion of the surface of the elastic body 63 facing the first member 4 on the side of the accommodation area 6, and reference numeral 63b denotes the surface of the elastic body 63 facing the first member 4. It represents the far side, ie the outer end, from the receiving area 6 . In the example shown in FIG. 20, the inclined surface 61b spreads from the end 63a of the surface of the elastic body 63 on the accommodation space 6a side to the outer end 63b. That is, the inclined surface 61b constitutes the entire surface of the elastic body 63 that faces the first member 4 and contacts the first member 4 . Note that the inclined surface 61 b may be a part of the surface of the elastic body 63 that faces the first member 4 and contacts the first member 4 .

In FIG. 20, reference numeral 62a denotes the end portion of the surface of the base portion 62 that contacts the elastic body 63 facing the first member 4, on the housing area 6 side, and reference numeral 62b denotes the elastic body facing the first member 4. 6 represents the end of the side of the base 62 which contacts and supports the elastic body 63 and which is remote from the receiving area 6, ie the outer end. In the example shown in FIG. 20 , of the surfaces of the base 62 , the outer end 62 b of the base 62 is positioned closest to the first member 4 in the moving direction of the sealing step first heat bar 61 . In addition, among the surfaces of the elastic body 63 , the end portion 63 a of the elastic body 63 on the housing area 6 side is located farthest from the first member 4 in the moving direction of the sealing step first heat bar 61 . In this case, the end portion 63 a of the elastic body 63 on the accommodation area 6 side contacts the first member 4 last among the surfaces of the elastic body 63 facing the first member 4 . Preferably, the portion, such as the end portion 63 a , which comes into contact with the first member 4 last, is the portion ( Here, it is positioned closer to the first member 4 than the end portion 62b). As a result, it is possible to prevent the first member 4 from being excessively pressed by the portion of the surface of the base portion 62 that is closest to the elastic body 63 .

Next, a method of bonding the exterior body 3 in the opening region 3b using the sealing process heat sealer 60 will be described. When the sealing step first heat bar 61 is moved to the first member 4 side, as shown in FIG. The sealing step first heat bar 61 is contacted with the elastic body 63 prior to the portion where the sealing step is performed, and is heated and pressed. Therefore, the exterior body bonding layer 8 is formed on the outer portion of the first member 4 . At this time, the portion of the elastic body 63 that is in contact with the first member 4 is compressed and deformed in the moving direction of the first heat bar 61 in the sealing process, as shown in FIG. The force applied to the first member 4 by the sealing step first heat bar 61 increases as the amount of compressive deformation of the elastic body 63 increases.

FIG. 22 shows that the sealing process first heat bar 61 is moved to the first member 4 until the part of the first member 4 located on the housing area 6 side also comes into contact with the elastic body 63 of the sealing process first heat bar 61 . It shows the state moved to the side. In the state shown in FIG. 22, the elastic body 63 is in contact with the entire area of the first member 4 to be the sealing region 7, and the elastic body 63 is compressed and deformed. The degree of compressive deformation of the elastic body 63 is greater toward the outside. For this reason, the force applied to the first member 4 by the sealing process first heat bar 61 is greater toward the outside.

While the first member 4 is being heated and pressed by the sealing step first heat bar 61, the thermoplastic resin layer 4b of the first member 4 and the thermoplastic resin layer 5b of the second member 5 are melted. A thermoplastic resin in a molten state has fluidity. In addition, the force applied to the first member 4 by the sealing process first heat bar 61 is greater toward the outside. For this reason, the thermoplastic resin in a molten state receives a force directed toward the housing space 6a from the outside. Therefore, even if the electrolyte 8s adheres to the inner surface of the first member 4 or the inner surface of the second member 5, as shown in FIGS. can be moved. Therefore, as shown in FIG. 22, it is possible to prevent the electrolytic solution 8s from remaining on at least the outer portion of the exterior body bonding layer 8 . As a result, at least a portion of the exterior body bonding layer 8 can be provided with a portion where the electrolyte solution 8s does not remain and which has sufficient bonding strength. As a result, it is possible to prevent the accommodation space 6a of the exterior body 3 from communicating with the outside.

Also, consider a case where the thick portion 7a has already been formed in the vicinity of the opening region 3b in the bonding step of the accommodation step when the sealing step is performed. In this case, since the first pressing surface 61 a of the sealing process first heat bar 61 is made of the elastic body 63 , when pressing the first member 4 using the sealing process first heat bar 61 , the first The shape of the pressing surface 61a can be elastically deformed according to the shape of the thick portion 7a. Therefore, the first pressing surface 61a can be brought into contact with the first member 4 in the opening region 3b without being obstructed by the thick portion 7a. As described above, it is possible to bond the first member 4 and the second member 5 by pressing the first member 4 while bringing the first pressing surface 61a into contact with the opening region 3b.

Although one embodiment has been described above with reference to specific examples, the above-described specific examples are not intended to limit one embodiment. The embodiment described above can be implemented in various other specific examples, and various omissions, replacements, and modifications can be made without departing from the spirit of the embodiment.

1 Laminated type battery 2 Membrane electrode assembly 3 Exterior body 3b Opening region 3c First side 3d Second side 3e Third side 3f Fourth side 3g External region side 4 First member 4a Base material 5 Second member 5a Base material 6 Accommodating area 6a Accommodating space 7 Sealing area 71 First sealing area 711 First part 712 Second part 72 Second sealing area 73 First side sealing area 74 Second side sealing area 75 Third side sealing area 76 Fourth side sealing region 76a Fourth side partial sealing region 7a Thick part 7a1 First thick part 7a2 Second thick part 7b First flat part 7c Second flat part 7d Third flat part 7e Peripheral flat part 8 Exterior body bonding layer 8s Electrolyte solution 9 External region 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 electrode plate 21 Second electrode collector 21Y Negative collector 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 50 Bonding process heat sealer 51 Bonding process first heat bar 51a First pressing surface 56 Bonding process second heat bar 56a Second pressing surface 60 Sealing process heat sealer 61 Sealing process first heat bar 61a First pressing surface 61b Slanted surface 62 Base 63 Elastic body 66 Sealing step Second heat bar 66a Second pressing surface

Claims (12)

a preparation step of preparing a membrane electrode assembly having first electrode plates and second electrode plates alternately laminated;
A housing step of housing the membrane electrode assembly inside an exterior body having a rectangular first member and a second member including a first side, a second side, a third side, and a fourth side, The exterior body includes a storage area defined between the first member and the second member to store a storage space for storing the membrane electrode assembly, and an outer periphery of the storage area. and a first sealing region where the second member is joined, and an opening region located on the outer periphery of the housing region and where the first member and the second member are not joined, The first sealing region includes a first side sealing region extending along the first side of the exterior body, a second side sealing region extending along the second side of the exterior body, and the first side sealing region extending along the second side of the exterior body. a third side sealing region extending along the third side of the exterior body from the side sealing region to the second side sealing region; and the first side sealing region of the fourth side of the exterior body. and a fourth side partial sealing region located partly between the second side sealing region, and the opening region is located on the first side sealing region of the fourth side of the exterior body. a containing step positioned partly between the sealing region and the second side sealing region;
an electrolytic solution injection step of injecting an electrolytic solution into the housing space of the exterior body through the opening region;
a sealing step of joining the first member and the second member in the opening region of the exterior body to form a second sealing region ;
The first member and the second member each include a base material and a thermoplastic resin layer positioned closer to the housing space than the base material,
In the sealing step, in the opening region of the exterior body, the first member is heated and pressed toward the second member to melt the thermoplastic resin layer. By forming a second exterior bonding layer for bonding the first member and the second member from the thermoplastic resin layer of the first member and the thermoplastic resin layer of the second member, the joining the first member and the second member to form the second sealing region;
The method for manufacturing a stacked battery, wherein in the sealing step, the second sealing region is formed such that the thickness of the second sealing region is larger than the thickness of the first sealing region. After the electrolyte solution injection step and before the sealing step, an initial charging step of charging the membrane electrode assembly housed inside the exterior body is further provided,
2. The method of manufacturing a stacked battery according to claim 1, wherein said initial charging step includes a gas venting step of removing gas generated by charging said membrane electrode assembly from said housing space through said opening region. The opening region has a dimension of 0.05 to 0.3 times the distance between the first side sealing region and the second side sealing region in the direction in which the fourth side extends. 3. The manufacturing method of the laminated type battery according to claim 1 or 2. 4. The method of manufacturing a stacked battery according to claim 1, wherein the opening region is positioned between the second side sealing region and the fourth side partial sealing region. The fourth side partial sealing region has a first portion located on the first side and a second portion located on the second side,
4. The method of manufacturing a stacked battery according to claim 1, wherein said opening region is positioned between said first portion and said second portion. The first member and the second member each include a base material and a thermoplastic resin layer positioned closer to the housing space than the base material,
The accommodation step includes a first step of joining the first member and the second member from the thermoplastic resin layer of the first member and the thermoplastic resin layer of the second member at the outer periphery of the accommodation area. 6. The method for manufacturing a stacked battery according to claim 1 , further comprising a bonding step of forming said first sealing region by forming an exterior body bonding layer. In the sealing step, the thickness of the second exterior body bonding layer is equal to the thickness of the thermoplastic resin layer of the first member in the opening region before the sealing step and the thermoplastic resin layer of the second member. 7. The method of manufacturing a stacked type battery according to claim 6 , wherein the second sealing region is formed so as to account for 90% or more of the total thickness of the layers. In the bonding step of the housing step, the thickness of the first exterior body bonding layer is equal to the thickness of the thermoplastic resin layer of the first member at the outer periphery of the housing area before the bonding step and the thickness of the thermoplastic resin layer of the second member. 8. The method of manufacturing a stacked type battery according to claim 6 , wherein said first sealing region is formed so as to be less than 90% of the total thickness of said thermoplastic resin layer. In the sealing step, the sealing step first heat bar is used in the opening region of the exterior body to press the first member toward the second member while heating the first member, joining the first member and the second member;
The laminate according to any one of claims 1 to 8 , wherein the sealing step first heat bar has an elastic body including an inclined surface facing the first member, and a base supporting the elastic body. A method for manufacturing a type battery. 10. The method of manufacturing a stacked type battery according to claim 9 , wherein said inclined surface of said elastic body is inclined such that a distance between said inclined surface and said first member increases toward said housing area. . 11. The apparatus according to claim 9 , wherein the inclined surface of the elastic body constitutes the entire surface of the elastic body that faces and contacts the first member among the surfaces of the elastic body. A method for manufacturing the laminated battery described. A portion of the surface of the elastic body facing the first member that is positioned furthest from the first member is a portion of the surface of the base supporting the elastic body that is positioned closest to the first member. 12. The method for manufacturing a stacked battery according to any one of claims 9 to 11 , located closer to said first member than said first member.

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