WO2020067226A1

WO2020067226A1 - Laminate-type secondary battery and method for producing same

Info

Publication number: WO2020067226A1
Application number: PCT/JP2019/037727
Authority: WO
Inventors: 浩也吉岡
Original assignee: 積水化学工業株式会社
Priority date: 2018-09-28
Filing date: 2019-09-26
Publication date: 2020-04-02
Also published as: TW202023094A; CN112514128A; CN112514128B; JP2020057484A; JP7171351B2

Abstract

This method for producing a laminate-type secondary battery comprises a step in which heat bars 51 are brought into contact with the part of a laminate casing 40, which houses an electrode body 5, where casing materials 41 of the laminate casing are oppositely disposed, and as a result thereof, the oppositely disposed casing materials 41 are welded together. The heat bars contact contact-regions CT1 positioned on the inside of a peripheral edge ce of the laminate casing.

Description

Laminated secondary battery and method of manufacturing the same

The present invention relates to a laminated secondary battery and a method for manufacturing a laminated secondary battery.

In recent years, a laminated secondary battery manufactured by sealing a battery element (electrode body) in a laminate exterior body has been widely used (for example, JP2014-517458A and JP2017-130374A). The laminate exterior body is usually produced using an exterior material having a thin metal layer such as aluminum and a sealant layer laminated on the metal layer. By folding one exterior material or by laminating two exterior materials, the exterior materials arranged opposite to each other are heated and welded to obtain a laminated exterior body that seals the battery element.

外装 The facing exterior materials forming the laminate exterior body are arranged such that the sealant layers face each other. The sealant layer usually contains a resin having thermoplasticity. By contacting the heat bar with the exterior material and heating the exterior material, the two facing sealant layers are welded, and the two laminated exterior materials can be joined (sealed).

However, when the exterior material is welded using the heat bar, the melted sealant material may leak out from the peripheral portion of the laminate exterior body and adhere to the heat bar. The sealant material adhered to the heat bar then adheres to the laminate exterior to be processed, and contaminates the laminate exterior. In order to avoid such a problem, it is necessary to remove the sealant material attached to the heat bar each time. Such a heat bar cleaning operation significantly impairs the productivity of the laminated secondary battery.

The present invention has been made in consideration of the above points, and has as its object to improve the productivity of a laminated secondary battery.

The manufacturing method of the laminated secondary battery according to the present invention,
A method of manufacturing a laminate type secondary battery including a laminate exterior body formed using an exterior material including a metal layer and a sealant layer laminated on the metal layer, and an electrode body disposed in the laminate exterior body And
A step of welding the exterior material arranged oppositely by contacting a heat bar to a portion where the exterior material of the laminate exterior body that accommodates the electrode body is arranged oppositely,
The heat bar contacts a contact area located inside a peripheral portion of the laminate exterior body.

において In the method for manufacturing a laminated secondary battery according to the present invention, the contact region may be separated from a peripheral portion of the laminate exterior body by 0.5 mm or more.

The manufacturing method of the laminated secondary battery according to the present invention,
Further comprising a step of contacting a heat bar with the second contact region of the laminate exterior body and welding an exterior material arranged opposite thereto,
One edge in the longitudinal direction of the second contact region may be located in the contact region, or one edge in the longitudinal direction of the contact region may be located in the second contact region. .

In the method for producing a laminated secondary battery according to the present invention,
The overlap region of the contact region and the second contact region has a length in the longitudinal direction of the contact region that is equal to or greater than 2/5 of the width of the second contact region along the longitudinal direction of the contact region. The overlapping region may have a length in the longitudinal direction of the second contact region that is equal to or greater than 2/5 of the width of the contact region along the longitudinal direction of the second contact region.

The manufacturing method of the laminated secondary battery according to the present invention,
Further comprising a step of contacting a heat bar with a third contact region of the laminate exterior body and welding an exterior material arranged opposite thereto;
One edge in the longitudinal direction of the third contact region may be located in the contact region, or the other edge in the longitudinal direction of the contact region may be located in the third contact region. .

In the method for producing a laminated secondary battery according to the present invention,
The laminate exterior body has a rectangular shape in plan view,
The contact area, the second contact area, and the third contact area may extend linearly along each of the three different edges of the rectangular shape.

Laminated secondary battery according to the present invention,
A laminate exterior body formed using an exterior material including a metal layer and a sealant layer laminated on the metal layer,
Having a plurality of electrodes, and an electrode body housed in the laminate exterior body,
The laminate exterior body has a linear welded portion in which exterior materials arranged opposite to each other are welded,
The thickness of the laminated exterior body at the welded portion is greater at both end portions in the longitudinal direction of the welded portion than at a portion located between the both end portions.

In the laminated secondary battery according to the present invention, the welded portion may be connected to an edge of the laminate exterior body at the both end portions.

In the laminated secondary battery according to the present invention, the total thickness of the sealant layer at the both end portions of the welded portion of the laminate exterior body may be located between the both end portions of the welded portion of the laminate exterior body. At least two times the total thickness of the sealant layer at the portion where the sealant layer is formed.

In the laminate type secondary battery according to the present invention, the thickness of the laminate exterior body at the welded portion may be maximized at the both end portions.

In the laminate type secondary battery according to the present invention,
The laminate exterior body further includes a linear second welded portion in which an exterior material that extends linearly and intersects with the welded portion and is disposed to face is welded,
The thickness of the laminate exterior body at the welded portion is greater at an end portion located between the overlapped portion and the edge of the laminate exterior body than at an overlapped portion that intersects with the second welded portion. You may.

In the laminated secondary battery according to the present invention, the thickness of the laminate outer body at the end portion may be twice or more the thickness of the laminate outer body at the overlapping portion.

According to the present invention, the productivity of the laminated secondary battery can be improved by suppressing the adhesion of the sealant to the heat bar.

FIG. 1 is a view for explaining one embodiment of the present invention, and is a perspective view showing a laminated secondary battery. FIG. 2 is a perspective view showing the inside of the laminate type secondary battery of FIG. 1 from which a laminate exterior body, an insulator and the like are removed. FIG. 3 is a vertical cross-sectional perspective view for explaining a laminated structure of an electrode plate and an insulator of the laminated secondary battery of FIG. FIG. 4 is a top view showing an electrode plate and an insulator of the laminated secondary battery of FIG. FIG. 5 is a longitudinal sectional view showing a section along the width direction of the laminate type secondary battery of FIG. FIG. 6 is a partial vertical cross-sectional view showing a cross section of the laminate type secondary battery of FIG. 1 along a take-out direction. FIG. 7 is a plan view showing the laminate type secondary battery of FIG. 1, and is a diagram for explaining a contact region by a heat bar and a welded portion. FIG. 8 is a view for explaining the method for manufacturing the laminated secondary battery in FIG. 1, and is a cross-sectional view showing a step of forming a welded portion. FIG. 9 is an enlarged view of FIG. 7 and is a view for explaining the positional relationship between the first contact area and the second contact area. FIG. 10 is a diagram corresponding to FIG. 9 and is a diagram for explaining a modification of the positional relationship between the first contact region and the second contact region. FIG. 11 is a view corresponding to FIG. 9 and is a view for explaining another modification of the positional relationship between the first contact area and the second contact area. FIG. 12 is a diagram corresponding to FIG. 9 and is a diagram for explaining still another modified example of the positional relationship between the first contact region and the second contact region. FIG. 13 is a diagram corresponding to FIG. 9 and is a diagram for explaining still another modified example of the positional relationship between the first contact region and the second contact region. FIG. 14 is a cross-sectional view taken along the line XIV-XIV of FIG. 9, and is a diagram for describing the thickness of the laminate exterior body. FIG. 15 is a plan view schematically illustrating a laminate type secondary battery according to an example. FIG. 16 is a view corresponding to FIG. 8 and is a view for explaining a conventional manufacturing method of a laminated secondary battery.

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.

FIGS. 1 to 14 are diagrams for explaining an embodiment of the present invention.

In one embodiment described below, a laminate type secondary battery 1 includes a laminate exterior body 40, an electrode body 5 housed in the laminate exterior body 40, and a laminate exterior body 40 connected to the electrode body 5. And a tab 3 extending from the inside to the outside. Of these, the laminate exterior body 40 is formed by welding the peripheral edges of the exterior materials 41 arranged to face each other. That is, the welded portions MJ1, MJ2, and MJ3 formed by welding (adhering) the two opposing

portions

41A and 41B of the exterior material 41 are provided on the periphery of the laminate exterior body 40. The tab 3 passes between the two

portions

41A and 41B of the exterior material 41 and extends from the inside of the laminate exterior body 40 to the outside. The electrode body 5 includes a first electrode plate 10 and a second electrode plate 20 that are alternately stacked, and an insulator 30 located between the first electrode plate 10 and the second electrode plate 20.

In the following, an example in which the laminate type secondary battery 1 constitutes a laminate type 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, but is also applicable to secondary batteries other than lithium ion. The present invention is not limited to a stacked secondary battery, and can be applied to a wound secondary battery. That is, the present embodiment can be widely applied to the laminate type secondary battery 1 in which the electrode body 5 is accommodated in the laminate exterior body 40.

First, the configuration of the laminate exterior body 40 will be described. The laminate exterior body 40 is a packaging material for sealing the electrode body 5. As shown in FIG. 1, FIG. 5, and FIG. 6, the laminate exterior body 40 has an exterior material 41 that is arranged to face each other. The laminate exterior body 40 may include two separate exterior materials 41, or the first portion 41A and the first exterior material 41A of the exterior material 41 facing each other by folding one exterior material 41 as in the illustrated example. The second portion 41B may be included. The exterior material 41 has a metal layer 44 and a sealant layer 45 laminated on the metal layer 44 (see FIGS. 5 and 6). The metal layer 44 preferably has high gas barrier properties and moldability.

The material forming the metal layer 44 is not particularly limited as long as it improves the strength of the entire laminated secondary battery while preventing invasion of moisture from the outside. Metals, metal oxides, metal nitrides, and alloys thereof can be used. Aluminum, an aluminum alloy, stainless steel, or the like is preferable, and aluminum is particularly preferably used. As long as the strength of the whole battery can be ensured, a metal layer may be provided by vapor deposition or sputtering instead of the metal foil.

(4) The sealant layer 45 has an insulating property and prevents a short circuit between the metal plates 44 and the electrode plates 10 and 20 housed in the laminate exterior body 40. In addition, the sealant layer 45 has thermoplasticity (adhesion) in addition to insulation. The first portion 41A and the second portion 41B of the exterior material 41 are stacked such that the sealant layers 45 face each other. The first portion 41A and the second portion 41B of the exterior material 41 are welded to each other except for the folded portion RP of the outer peripheral portion ce of the laminated exterior body 40 where the exterior material 41 is folded. Further, a housing space RS for the electrode body 5 is formed between the first portion 41A and the second portion 41B of the exterior material 41. The laminate exterior body 40 seals the electrode body 5 and the electrolytic solution in the accommodation space RS. The sealant layer 45 preferably has chemical resistance because it comes into contact with the electrolytic solution. As a material of such a sealant layer 45, a polyolefin-based resin, specifically, polypropylene, modified polypropylene, low-density polypropylene, ionomer, ethylene / vinyl acetate can be used.

In the illustrated example, the first portion 41A of the exterior material 41 is a plate-shaped member. On the other hand, the second portion 41B of the exterior material 41 is formed in a cup shape. The second portion 41B has a cup-shaped bulging portion 42a and a flange portion 42b connected to the bulging portion 42a. The flange portion 42b circumferentially surrounds the bulging portion 42a and is connected to the periphery of the bulging portion 42a. The flange 42b is welded to the second part 41B so as to seal the accommodation space RS between the first part 41A and the second part 41B. The bulging portion 42a may be manufactured by, for example, drawing, or may be a portion formed by deforming the flexible exterior material 41 according to the electrode body 5.

However, the present invention is not limited to the above example, and the laminate exterior body 40 may have two exterior materials. At the position to be the peripheral portion ce of the laminate exterior body 40, the two exterior materials are welded in a circumferential shape, so that the closed accommodation space RS can be formed.

The tab 3 functions as a terminal in the laminated secondary battery 1. One tab 3 is electrically connected to the positive electrode plate 10X (first electrode plate 10) of the electrode body 5, and the other tab 3 is electrically connected to the negative electrode plate 20Y (second electrode plate 20) of the electrode body 5. doing. The tab 3 can be formed using aluminum, nickel, nickel-plated copper, or the like. The pair of tabs extend from the inside of the laminate case 40 to the outside of the laminate case 40. In the illustrated example, the tab 3 is pulled out of the electrode body 5 to the outside of the laminate exterior body 40 along the drawing direction dx.

The space between the laminate exterior body 40 and the tab 3 is sealed in a region where the tab 3 extends. Specifically, as shown in FIGS. 1 and 6, a seal member 4 is provided between the tab 3 and the laminate exterior body 40. The sealing material 4 seals the space between the tab 3 and the laminate exterior body 40 to seal the accommodation space RS of the laminate exterior body 40. Further, the sealing material 4 has adhesiveness, and joins the tab 3 and the laminate exterior body 40. As shown in FIG. 6, seal members 4 are provided on both sides of the tab 3 in the laminating direction dz of the electrode plates 10 and 20, respectively.

As shown in FIG. 7, in the illustrated laminated secondary battery 1, the laminated outer package 40 has a rectangular shape in plan view. The illustrated laminate exterior body 40 has a longitudinal direction in a drawing direction dx in which the tab 3 extends, and a short direction in a width direction dy perpendicular to the drawing direction dx. Therefore, the laminate exterior body 40 has a pair of long edges (first edge e1 and fourth edge e4) parallel to the drawing direction dx and a pair of short edges parallel to the width direction dy as the peripheral edge ce. (A second edge e2 and a third edge e3). The fourth edge e4 is a folded portion RP formed by folding the exterior material 41. Further, the laminate exterior body 40 includes a first welded portion MJ1 extending linearly along the first edge e1, a second welded portion MJ2 extending linearly along the second edge e2, and a third edge. and a third welding portion MJ3 extending linearly along e3. At each of the welded portions MJ1, MJ2, and MJ3, exterior members 41 arranged to face each other are welded. The second welded portion MJ2 is connected at both ends to the first welded portion MJ1 and the folded portion RP. Similarly, the third welded portion MJ3 is connected at both ends to the first welded portion MJ1 and the folded portion RP. The accommodation space RS is partitioned and sealed by the welded parts MJ1, MJ2, MJ3 and the folded part RP.

Next, the electrode body 5 will be described mainly with reference to the illustrated specific examples. The electrode body 5 has a positive electrode plate 10X (first electrode plate 10) and a negative electrode plate 20Y (second electrode plate 20), and an insulator 30 located between the positive electrode plate 10X and the negative electrode plate 20Y. . First, the positive electrode plate 10X and the negative electrode plate 20Y will be described.

電極 As shown in FIGS. 2, 3, 5, and 6, the electrode body 5 has a plurality of positive plates 10X (first electrode plates 10) and a plurality of negative plates 20Y (second electrode plates 20). The number of the positive electrode plate 10X (the first electrode plate 10) and the number of the negative electrode plate 20Y (the second electrode plate 20) are, for example, 10 or more, or 15 or more, or 20 or more in one laminate exterior body 40, respectively. include. The positive electrode plates 10X and the negative electrode plates 20Y are alternately arranged along the stacking direction dz. The electrode body 5 and the laminated secondary battery 1 have a flat shape as a whole, have a small thickness in the laminating direction dz, and extend in a drawing direction dx and a width direction dy orthogonal to the laminating direction dz.

In some drawings, the drawing direction dx, the width direction dy, and the laminating direction dz are shown as common directions between the drawings in order to clarify the directional relationship between the drawings.

において In the illustrated non-limiting example, the positive electrode plate 10X and the negative electrode plate 20Y have rectangular outer contours. The positive electrode plate 10X and the negative electrode plate 20Y have a longitudinal direction in a drawing direction dx perpendicular to the laminating direction dz, and a short direction in a width direction dy perpendicular to both the laminating direction dz and the drawing direction dx. As shown in FIG. 2 and FIG. 4, the positive electrode plate 10X and the negative electrode plate 20Y are arranged so as to be shifted in the drawing direction dx. More specifically, the plurality of positive electrode plates 10X are disposed closer to one side (lower left side in FIG. 2 and the left side in FIG. 4) in the drawing direction dx, and the plurality of negative electrode plates 20Y are positioned on the other side in the drawing direction dx. (The upper right side in FIG. 2 and the right side in FIG. 4). The positive electrode plate 10X and the negative electrode plate 20Y overlap in the stacking direction dz at the center in the drawing direction dx. In FIG. 2, illustration of the insulator 30 is omitted.

The positive electrode plate 10X (first electrode plate 10) has a sheet-like outer shape as shown in the figure. 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 is located at the outermost position in the stacking direction dz of the electrode plates 10 and 20 included in the electrode body 5, the positive electrode current collector The positive electrode active material layer 12X is not provided on the outermost surface of the conductor 11X. Except for the presence or absence of the positive electrode active material layer 12X depending on the position of the positive electrode current collector 11X, the plurality of positive electrode plates 10X included in the laminated secondary battery 1 have the positive electrode active material layers 12X on both sides of the positive electrode current collector 11X. And can be configured identically to each other.

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 laminated secondary 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.

正極 As shown in FIG. 4, the positive electrode current collector 11X (the first electrode current collector 11) has a first end region a1 and a first electrode region b1. The positive electrode active material layer 12X (first electrode active material layer 12) is disposed only in the first electrode region b1 of the positive electrode current collector 11X. The first end region a1 and the first electrode region b1 are arranged in the drawing direction dx. The first end region a1 is located outside (left side in FIG. 4) in the extraction direction dx from the first electrode region b1. As shown in FIG. 6, the plurality of positive electrode current collectors 11X are joined and electrically connected in the first end region a1 by resistance welding, ultrasonic welding, sticking with tape, fusion, or the like. . In the illustrated example, one tab 3 is electrically connected to the positive electrode current collector 11X in the first end region a1. The tab 3 extends from the electrode body 5 in the drawing direction dx. On the other hand, as shown in FIG. 4, the first electrode region b1 is located in a region of the negative electrode plate 20Y facing a negative electrode active material layer 22Y described later. Then, as shown in FIG. 5, the width of the positive electrode plate 10X along the width direction dy is smaller than the width of the negative electrode plate 20Y along the width direction dy. With such an arrangement of the first electrode 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. Specifically, when the first surface 21a or the second surface 21b of the negative electrode current collector 21Y is located at the outermost position in the stacking direction dz of the electrode plates 10 and 20 included in the electrode body 5, the negative electrode current collector 21Y The negative electrode active material layer 22Y is not provided on the outermost surface of the electric body 21Y. Except for the presence or absence of the anode active material layer 22Y depending on the position of the anode current collector 21Y, the plurality of anode plates 20Y included in the laminate type secondary battery 1 include the anode active material layers 22Y on both sides of the anode current collector 21Y. And can be configured identically to each other.

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 laminate type secondary 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.

負極 As shown in FIG. 4, the negative electrode current collector 21Y (second electrode current collector 21) has a second end region a2 and a second electrode region b2. The negative electrode active material layer 22Y (second electrode active material layer 22) is disposed in the second electrode region b2 of the negative electrode current collector 21Y. The second end region a2 and the second electrode region b2 are arranged in the drawing direction dx. The second end region a2 is located outside (in the right side in FIG. 4) in the extraction direction dx from the second electrode region b2. The plurality of negative electrode current collectors 21Y are joined and electrically connected to each other in the second end region a2 by resistance welding, ultrasonic welding, sticking with tape, fusion, or the like. One tab 3 can be electrically connected to the negative electrode current collector 21Y in the second end region a2. The tab 3 extends from the electrode body 5 in the drawing direction dx.

As described above, the first electrode region b1 of the positive electrode plate 10X is located inside the region facing the second electrode region b2 of the negative electrode plate 20Y (see FIG. 4). That is, the second electrode region b2 extends to a region including the region of the positive electrode plate 10X facing the positive electrode active material layer 12X. As shown in FIG. 5, the width of the negative electrode plate 20Y along the width direction dy is wider than the width of the positive electrode plate 10X along the width direction dy.

Next, the insulator 30 will be described. The insulator 30 is located between the positive electrode plate 10X (first electrode plate 10) and the negative electrode plate 20Y (second electrode plate 20). The insulator 30 prevents a short circuit due to contact between the positive electrode plate 10X (the first electrode plate 10) and the negative electrode plate 20Y (the second electrode plate 20). The insulator 30 preferably has high ion permeability (air permeability), predetermined mechanical strength, and durability with respect to an electrolytic solution, a positive electrode active material, a negative electrode active material, and the like. As such an insulator 30, for example, a porous body or a nonwoven fabric formed of an insulating material can be used. An electrolytic solution is sealed in the laminate exterior body 40 together with the electrode body 5. By impregnating the insulator 30 made of a porous body or a nonwoven fabric with the electrolyte, the electrolyte is kept in contact with the electrode active material layers 12 and 22 of the electrode plates 10 and 20.

In the illustrated example, the single insulator 30 is located between any two electrode plates 10 and 20 adjacent in the stacking direction dz. The insulator 30 is a bendable sheet-shaped member. The insulator 30 has a first surface 30a and a second surface 30b as a pair of main surfaces facing each other. As shown in FIGS. 3 and 5, the insulator 30 is alternately folded in the width direction dy in the opposite direction, thereby extending sequentially between the positive electrode plate 10 X and the negative electrode plate 20 Y adjacent in the stacking direction dz. The insulator 30 has a first folded portion 31 folded on one side in the width direction dy, and a second folded portion 32 folded on the other side opposite to the one side in the width direction dy. That is, the insulator 30 has a zigzag shape. However, in the present embodiment, the insulator 30 does not need to be in a serpentine shape, and the sheet-like insulator 30 is formed by the positive electrode plate 10X (the first electrode plate 10) and the negative electrode plate 20Y (the second electrode plate). 20), the positive electrode plate 10X (first electrode plate 10) and the negative electrode plate 20Y (second electrode plate 20) may be insulated.

絶縁 As shown in FIG. 4, in plan view, the insulator 30 extends so as to cover the entire area of the positive electrode active material layer 12X of the positive electrode plate 10X. Therefore, as shown in FIG. 5, the width of the insulator 30 in the width direction dy is wider than the width of the positive electrode plate 10X in the width direction dy. Further, the length of the insulator 30 in the extraction direction dx is longer than the length of the positive electrode active material layer 12X in the extraction direction dx.

Similarly, as shown in FIG. 4, in plan view, the insulator 30 extends so as to cover the entire area of the negative electrode active material layer 22Y of the negative electrode plate 20Y. That is, the width of the insulator 30 in the width direction dy is wider than the width of the negative electrode plate 20Y in the width direction dy. Further, the length of the insulator 30 in the extraction direction dx is longer than the length of the negative electrode active material layer 22Y in the extraction direction dx.

樹脂 A resinous porous film can be used as the insulator 30 described above. More specifically, a porous film made of a thermoplastic resin having a melting point of about 80 to 140 ° C. can be used as the insulator 30. As the thermoplastic resin, a polyolefin-based resin such as polypropylene and polyethylene can be used.

In addition, the insulator 30 may include a base layer and a functional layer laminated on the base layer. According to such a configuration, the first surface 30a of the insulator 30 facing the positive electrode plate 10X and the second surface 30b of the insulator 30 facing the negative electrode plate 20Y may have different properties. it can. For example, the functional layer having a large porosity may face the negative electrode plate 20Y in which the electrolyte is likely to dry in a large area, and the base material layer may face the positive electrode plate 10X. Further, as another example, the functional layer having excellent heat resistance may face the positive electrode plate 10 X, which easily rises in temperature, and the base material layer may face the negative electrode plate 20 Y. As the base material layer, for example, the resin porous film described immediately above can be used. As the functional layer, for example, a layer containing an inorganic material can be employed. The inorganic material can impart excellent heat resistance, for example, heat resistance of 150 ° or more to the functional layer. Examples of such an inorganic material include cellulose and modified substances thereof, polyolefin, polyethylene terephthalate, polybutylene terephthalate, polypropylene, polyester, polyacrylonitrile, aramid, polyamideimide, and fibrous materials and particulate materials such as polyimide. By using such an inorganic material, it becomes possible to give a higher porosity to the functional layer than to the base material layer.

Next, a method for manufacturing the laminated secondary battery 1 having the above-described configuration will be described.

First, the electrode body 5 is formed by laminating the positive electrode plate 10X and the negative electrode plate 20Y, and the insulator 30 that insulates the positive electrode plate 10X and the negative electrode plate 20Y. The positive electrode plate 10X, the negative electrode plate 20Y, and the insulator 30 can be manufactured by the above-described materials and the manufacturing method. Next, the manufactured positive electrode plate 10X, negative electrode plate 20Y, and insulator 30 are laminated so that the insulator 30 is located between the positive electrode plate 10X and the negative electrode plate 20Y. Thereby, the electrode body 5 is obtained. After that, the positive electrode current collectors 11X of the plurality of positive electrode plates 10X are electrically connected to each other and further to the tab 3. Similarly, the negative electrode current collectors 21 Y of the plurality of negative electrode plates 20 Y are electrically connected to each other and further to the tab 3.

(4) Next, an exterior material 41 for constituting the laminate exterior body 40 is prepared. The first part 41A and the second part 41B of the exterior material 41 face each other by folding the exterior material 41 at the folded part RP. In the folded exterior material 41, the sealant layer 45 is positioned inside. Next, the electrode body 5 is arranged between the first portion 41A and the second portion 41B. At this time, as shown in FIG. 7, each tab 3 is made to extend from between the first portion 41A and the second portion 41B of the first exterior material 41.

In addition, the bulging portion 42a may be formed in advance in a region to be the second portion 41B of the exterior material 41 by, for example, drawing. In this example, the electrode body 5 is housed in the bulging portion 42a.

Next, in a state where the electrode body 5 is disposed between the first portion 41A and the second portion 41B of the exterior material 41, the first portion 41A of the exterior material 41 and the first The two parts 41B are welded. In the illustrated example, the first portion 41A and the second portion 41B facing each other are welded to form three welded portions MJ1 to MJ3 in order.

The first welded portion MJ1 is formed along the first edge e1 of the laminate exterior body 40. The first welded portion MJ1 extends linearly along the drawing direction dx. In the illustrated example, the first welded portion MJ1 is connected to a pair of edges of the laminate exterior body 40 facing the drawing direction dx, that is, the second edge e2 and the third edge e3.

The second welded portion MJ2 is formed along the second edge e2 of the laminate exterior body 40. The second welded portion MJ2 extends linearly along the width direction dy. In the illustrated example, the second welded portion MJ2 is connected to a pair of edges of the laminate exterior body 40 facing each other in the width direction dy, that is, a first edge e1 and a fourth edge e4. Similarly, the third welded portion MJ3 is formed along the third edge e3 of the laminate exterior body 40. The third welded portion MJ3 extends linearly along the width direction dy. In the illustrated example, the third welded portion MJ3 is connected to a pair of edges of the laminate exterior body 40 facing each other in the width direction dy, that is, a first edge e1 and a fourth edge e4.

順番 The order of forming the three welds MJ1 to MJ3 is not particularly limited. Further, since the second welded portion MJ2 and the third welded portion MJ3 are not connected to each other, they can be formed in parallel. Further, when the last welded portion is formed, the electrolytic solution is contained in the containing space RS of the laminate exterior body 40 closed from three sides. As an example, the second welded part MJ2 and the third welded part MJ3 are manufactured sequentially or in parallel, and then the electrolyte is filled in the laminate exterior body 40, and then the first welded part MJ1 is manufactured. You may do so.

(8) The welds MJ1 to MJ3 are formed using a sealing device 50 having a heat bar 51 as a rod-shaped heating member, as shown in FIG. By pressing the heated pair of heat bars 51 against the exterior material 41 from both sides, the sealant layers 45 of the first portion 41A and the second portion 41B are melted, and then solidified to thereby form the first portion 41A and the second portion. 41B is welded. In the second welded portion MJ2 and the third welded portion MJ3, the outer material 41 is provided on the tab 3, and the sealing material 4 is welded to the outer material 41, and the space between the tab 3 and the outer material 41 is formed. Seal. When forming the welds MJ1 to MJ3, another heat bar 51 having a length corresponding to each weld can be used.

By the way, as shown in FIG. 16, conventionally, when the exterior material 141 is welded using the heat bar 151, the melted sealant material 146 leaks out from the peripheral edge ce of the laminate exterior body 140 and adheres to the heat bar 151. Was. The sealant material 146 adhered to the heat bar 151 subsequently adheres to the laminate exterior body 140 to be processed, and contaminates the laminate exterior body 140. In order to avoid such a problem, it is necessary to remove the sealant 146 attached to the heat bar 151 each time. Such a cleaning operation of the heat bar 151 significantly impaired the productivity of the laminated secondary battery 101.

Conventionally, it has been considered that it is necessary to press and heat and press the heat bar 151 over the entire length of the portion to be welded in order to reliably weld the exterior members 141 arranged opposite to each other. Therefore, when the welded portion is formed over the entire width of the exterior material 41, the entire length of the heat bar 151 is set sufficiently longer than the entire width of the exterior material 141, as shown in FIG. By using the heat bar 151 longer than the entire width of the exterior material 141, the sealant layer 145 laminated on the metal layer 144 could be melted in the region over the entire width of the exterior material 41. On the other hand, the melted sealant material 146 was squeezed out from the peripheral edge ce of the laminate exterior body 140 and adhered to the heat bar 151.

Therefore, in the present embodiment, as shown in FIGS. 7 and 8, the heat bar 51 is prevented from contacting the peripheral edge ce of the laminate exterior body 40 from which the sealant material can be squeezed out. According to such an embodiment, the productivity can be improved. Furthermore, in the laminate type secondary battery 1 manufactured by the method according to the present embodiment, the exterior material 41 was more firmly welded, and the sealing property of the accommodation space RS could be improved. Such an operation and effect can be said to be remarkable due to a heterogeneity beyond the range predicted from the conventional state of the art.

In the illustrated example, when forming the second welded portion MJ2, the heat bar 51 contacts and heats and presses the second contact area CT2. The second contact area CT2 extends linearly along the second edge e2 of the laminate exterior body 40. The second contact region CT2 includes a pair of edges EE2 and EE2 facing in the width direction dy, and an outer edge OE2 and an inner edge IE2 facing in the pull-out direction dx. One edge EE2 is located in the vicinity of the first edge e1, and extends along the first edge e1 in parallel with the drawing direction dx. The other edge EE2 is located near the fourth edge e4, and extends along the fourth edge e4 in parallel with the drawing direction dx. The inner edge IE2 is closer to the housing space RS than the outer edge OE2. The outer edge OE2 is closer to the second edge e2 than the inner edge IE2. The outer edge OE2 and the inner edge IE2 extend parallel to the width direction dy along the second edge e2.

(4) When forming the third welded portion MJ3, the heat bar 51 comes into contact with the third contact area CT3 to apply heat and pressure. The third contact area CT3 extends linearly along the third edge e3 of the laminate exterior body 40. The third contact region CT3 includes a pair of edges EE3 and EE3 facing in the width direction dy, and an outer edge OE3 and an inner edge IE3 facing in the drawing direction dx. The one edge EE3 is located near the first edge e1, and extends along the first edge e1 in parallel with the drawing direction dx. The other edge EE3 is located near the fourth edge e4, and extends along the fourth edge e4 in parallel with the drawing direction dx. The inner edge IE3 is closer to the housing space RS than the outer edge OE3. The outer edge OE3 is closer to the third edge e3 than the inner edge IE3. The outer edge OE3 and the inner edge IE3 extend parallel to the width direction dy along the third edge e3.

(4) When forming the first welded portion MJ1, the heat bar 51 comes into contact with the first contact region CT1 to heat and pressurize. The first contact area CT1 extends linearly along the first edge e1 of the laminate exterior body 40. The first contact region CT1 includes a pair of edges EE1 and EE1 facing in the drawing direction dx, and an outer edge OE3 and an inner edge IE3 facing in the width direction dy. One edge EE1 is located near the second edge e2 and extends parallel to the width direction dy along the second edge e2. The other edge EE1 is located near the third edge e3 and extends parallel to the width direction dy along the third edge e3. The inner edge IE1 is closer to the accommodation space RS than the outer edge OE1. The outer edge OE1 is closer to the first edge e1 than the inner edge IE1. The outer edge OE13 and the inner edge IE1 extend in parallel with the drawing direction dx along the first edge e1.

That is, the first contact region CT1, the second contact region CT2, and the third contact region CT3 are all separated from the peripheral edge ce of the laminate exterior body 40 and are located inside the peripheral edge ce of the laminate exterior body 40. doing.

As described above, the region where the heat bar 51 contacts the exterior material 41 is included in the peripheral edge ce of the laminate exterior body 40, so that the melted sealant material leaks from the peripheral edge ce of the laminate exterior body 40. This can be effectively prevented. Therefore, the adhesion of the melted sealant material to the heat bar 51 can be effectively avoided, and the productivity of the laminated secondary battery 1 can be effectively improved.

In the illustrated example, the fourth edge e4 of the laminate exterior body 40 is a folded portion RP formed by folding the exterior material 41. Therefore, the melted sealant does not leak from the fourth edge e4. Therefore, the second contact region CT2 and the third contact region CT3 may intersect with the fourth edge e4, or the other edges EE2 and EE3 may be located on the fourth edge e4. Good.

において From the viewpoint of avoiding leakage of the sealant from the peripheral edge ce of the laminate exterior body 40, the contact areas CT1, CT2, and CT3 are preferably separated from the peripheral edge ce of the laminate exterior body 40 by 0.5 mm or more. By setting this distance to 0.5 mm or more, the sealant melted from the peripheral edge ce of the laminate exterior body 40 under the general welding condition of the laminate exterior body 40 at the time of manufacturing the laminate type secondary battery 1 Leakage of material can be effectively avoided. For example, with reference to the first contact area CT1, the separation distance L1x (see FIG. 9) between the one edge EE1 and the second edge e2 of the first contact area CT1 along the drawing direction dx is 0. It is preferably at least 0.5 mm. The distance between the other edge EE1 of the first contact area CT1 and the third edge e3 in the pull-out direction dx is preferably 0.5 mm or more. It is preferable that the separation distance L1y (see FIG. 9) along the width direction dy between the outer edge OE1 of the first contact region CT1 and the first edge e1 is 0.5 mm or more.

よう As shown in FIG. 7, it is preferable that the first contact area CT1 is connected (overlaps) with the second contact area CT2. In this case, the first welded portion MJ1 formed by the contact of the heat bar 51 with the first contact region CT1 and the second welded portion MJ2 formed by the contact of the heat bar 51 with the second contact region CT2 are stable. And the connection can be performed, and the hermetic sealing of the accommodation space RS can be ensured more reliably. For the same reason, it is preferable that the first contact region CT1 is connected (overlaps) with the third contact region CT3.

In the example shown in FIG. 9, the edge (EE1) of one contact area (first contact area CT1) is located on the outer edge (outer edge OE2) of the other contact area (second contact area CT2). The edge (EE2) of the other contact area (second contact area CT2) is located on the outer edge (outer edge OE1) of the one contact area (first contact area CT1). According to such an example, the two welded portions (the first welded portion MJ1 and the second welded portion MJ2) to be formed can be more reliably connected.

However, the positional relationship between the two contact areas is not limited to the example shown in FIG. 9, and for example, the examples shown in FIGS. 10 to 13 can be adopted. 9 to 13, one contact area (first contact area CT1) is indicated by a dotted line, and the other contact area (second contact area CT2) is indicated by a dashed line.

First, in the example shown in FIG. 10, one contact region (first welded portion MJ1) and the other contact region (second welded portion MJ2) intersect. That is, one contact area (first welded part MJ1) crosses the other contact area (second welded part MJ2). Further, the other contact region (second welded portion MJ2) crosses one contact region (first welded portion MJ1). According to this example, the two welded portions (the first welded portion MJ1 and the second welded portion MJ2) to be formed can be more reliably connected.

Next, in the examples shown in FIGS. 11 and 12, one edge in the longitudinal direction of one contact region is located in the other contact region. In the example shown in FIG. 11, one end edge EE1 in the longitudinal direction (drawing direction dx) of the first contact region CT1 is located in the second contact region CT2. In the example shown in FIG. 12, one edge EE2 in the longitudinal direction (width direction dy) of the second contact region CT2 is located in the first contact region CT1. In the example shown in FIG. 13, one contact region and the other contact region overlap with each other only in a part of the width along the short direction orthogonal to each longitudinal direction. According to the examples shown in FIG. 9 and FIGS. 11 to 13, the lengths L1 and L2 from each contact area to the peripheral edge ce of the laminate exterior body 40 can be reduced. Thereby, the energy density of the laminated secondary battery 1 can be improved.

The overlapping area OA of one contact area (first contact area CT1) and the other contact area (second contact area CT2) is one contact area in the longitudinal direction of one contact area (drawing direction dx). Of the other contact area along the longitudinal direction (the width W2 of the second contact area CT2) preferably has a length LOx or more, and has a length LOx of 1/2 or more. More preferably, it has a length ＬＯ of 2/3. Similarly, the overlapping area OA of one contact area (first contact area CT1) and the other contact area (second contact area CT2) is in the longitudinal direction (width direction dy) of the other contact area. It is preferable to have a length LOy equal to or more than ／ of the width of one contact area along the longitudinal direction of the area (the width W1 of the first contact area CT1). It is more preferable to have the length LOx of ＬＯ. By setting the overlapping area OA to such a size, as described below, it is possible to improve the sealing around the overlapping portion OP where the two welded portions overlap.

As described above, the second welded portion MJ2 is formed by bringing the pair of heat bars 51 into contact with the exterior material 41 from both sides in the second contact region CT2, and the pair of heat bars 51 is brought into contact with the exterior material 41 in the third contact region CT3. Is contacted from both sides to form a third welded portion MJ2. The melting of the sealant layer 45 of the exterior material 41 is not limited to the region overlapping the contact regions CT2 and CT3 with which the heat bar 51 is in contact. The sealant layer 45 also melts around the area overlapping the contact areas CT2 and CT3. Therefore, as shown in FIG. 7, the area occupied by the second welded portion MJ2 on the laminate exterior body 40 includes the area occupied by the second contact area CT2 on the laminate exterior body 40. The area occupied by the third welded portion MJ3 above includes the area occupied by the third contact area CT3 on the laminate exterior body 40.

Similarly, the first welded portion MJ1 is formed by bringing the pair of heat bars 51 into contact with the exterior material 41 from both sides in the first contact region CT1. The area occupied by the first welded portion MJ1 on the laminate exterior body 40 includes the area occupied by the first contact area CT1 on the laminate exterior body 40. Further, as shown in FIG. 7, the first welded portion MJ1 is connected or intersected with the second welded portion MJ2, and the connection is intersected with the third welded portion MJ3.

{Circle around (2)} In the overlap region OA of the first contact region CT1 and the second contact region CT2 and around the overlap region OA, when the first weld portion MJ1 is formed, the already-formed second weld portion MJ2 is melted again. Therefore, the first welded portion MJ1 and the second welded portion MJ2 are formed integrally and continuously, and the liquid tightness of the housing space RS can be ensured. Similarly, the first welded portion MJ1 and the third welded portion MJ3 are also formed integrally and continuously, so that the liquid tightness of the accommodation space RS can be ensured.

As described above, the welded portions MJ1 to MJ3 are formed on the laminate exterior body 40, and the electrode body 5 and the electrolyte are sealed in the housing space RS, whereby the laminate type secondary battery 1 is obtained. Surprisingly, the laminated secondary battery 1 obtained in this manner has improved sealing of the accommodation space RS and has high reliability. The inventors of the present invention have confirmed that the reason why the sealing performance of the laminated secondary battery 1 is improved is that the thickness of the welded portion obtained by the manufacturing method according to the present embodiment varies. Hereinafter, this point will be described, but the present invention is not restricted by the following presumption.

FIG. 14 is a cross-sectional view showing one welded portion obtained by the above-described method, and corresponds to, for example, a cross-section taken along line XIV-XIV in FIG. The first welded portion MJ1 has an end portion EP located outside the first contact region CT1, an overlap portion OP located in the overlap region OA of the first contact region CT1, and a first contact region CT1. And a central part MP located outside the overlapping area OA. That is, the first welded portion MJ1 includes the end portion EP that has never been pressed by the heat bar 51, the overlap portion OP that has been pressed twice by the heat bar 51, and the central portion MP that has been pressed once by the heat bar 51. Contains.

Then, as shown in FIG. 14, the thickness at the first welded portion MJ1 of the laminate exterior body 40 is determined at both end portions EP in the longitudinal direction of the first welded portion MJ1 connected to the peripheral edge ce of the laminate exterior body 40. It is thicker than the portion (overlapping portion OP or central portion MP) located between both end portions EP. As described above, the thickness of the laminate exterior body 40 at the portion outside the overlapping portion OP where the two weld portions overlap (opposite to the housing space RS) is increased, so that the tightness of the laminated secondary battery 1 is improved. Could be improved.

In particular, the total thickness of the sealant layer 45 (the total thickness of the two welded sealant layers 45) at the end portion EP of the first welded portion MJ1 of the laminate exterior body 40 is equal to the end of the first welded portion MJ1 of the laminate exterior body 40. When the total thickness of the sealant layer 45 in a certain portion other than the portion EP (the overlapping portion OP and the central portion MP) is twice or more, it is possible to greatly improve the sealing performance of the laminated secondary battery 1. did it.

In the laminate exterior body 40 shown in FIG. 14, the thickness at the first welded portion MJ1 is the largest at both ends EP. This point can also contribute to improving the sealing performance of the laminated secondary battery 1.

It should be noted that the present inventor has confirmed that, in order to realize the thickness distribution along the longitudinal direction of the welded portion shown in FIG. Has a length LOx in the longitudinal direction of one contact region that is equal to or greater than 2/5 of the width of the other contact region along the longitudinal direction of the one contact region, and In the longitudinal direction of the region, it was effective to have a length LOy equal to or more than 2/5 of the width of one contact region along the longitudinal direction of the other contact region. In this case, in the experiment performed by the present inventor, the total thickness of 0.32 mm of the sealant layer 45 included in the first portion 41A and the second portion 41B of the exterior material 41 arranged opposite to each other before the welding is determined by the welding. Later, it increased to 0.58 mm in the end portion EP, decreased to 0.20 mm in the overlapping portion OP, and decreased to 0.25 mm in the central portion MP. In the welded portion of the laminated secondary battery 1 obtained in this experiment, the total thickness of the sealant layer 45 is maximum at the end portion EP, and the total thickness of the sealant layer 45 at the end portion EP is the sealant layer other than at the end portion. 45 was 2.9 times the total thickness. As a result, the obtained laminate type secondary battery 1 had excellent airtightness.

In the embodiment described above, the manufacturing method of the laminated secondary battery 1 is such that the heat bar 51 is brought into contact with the part of the laminate outer body 40 that houses the electrode body 5 where the outer material 41 is disposed to face the outer body 41. And a step of welding the facing material 41 arranged opposite to each other. During this process, the heat bar 51 comes into contact with the contact area CT1 located inside the peripheral edge ce of the laminate casing 40. That is, the contact area CT1 is separated from the peripheral edge ce of the laminate exterior body 40. Therefore, since the sealant layer 45 located at the peripheral edge ce of the laminate exterior body 40 is directly heated by the heat bar 51, it is possible to prevent the melted sealant material from leaking from the laminate exterior body 40. Thereby, it is possible to effectively prevent the sealant from adhering to the sealing device 50 such as the heat bar 51. Accordingly, it is possible to continuously produce a large number of laminated secondary batteries 1 using the same heat bar 51, and the productivity of the laminated secondary batteries 1 can be improved.

In the above-described embodiment, the contact area is separated from the peripheral edge ce of the laminate exterior body 40 by 0.5 mm or more. According to such an example, it is possible to sufficiently and effectively prevent the molten sealant material from leaking out of the laminate exterior body 40.

In one embodiment described above, the manufacturing method of the laminated secondary battery 1 includes a step of bringing the heat bar 51 into contact with the second contact region CT2 of the laminated exterior body 40 and welding the exterior material 41 that is arranged to face the second exterior area CT2. In addition. One edge EE2 of the second contact region CT2 in the longitudinal direction (width direction dy) is located within the contact region CT1 or one edge EE1 of the contact region CT1 in the longitudinal direction (drawing direction dx) is It is located in the second contact area CT2. According to this example, the laminated secondary battery 1 having excellent sealing performance can be manufactured. Further, the size of the laminate exterior body 40 can be reduced, and the energy density of the laminate type secondary battery 1 can be improved.

In the above-described embodiment, the overlapping area OA of the contact area CT1 and the second contact area CT2 is the second contact area along the longitudinal direction of the contact area CT1 in the longitudinal direction (drawing direction dx) of the contact area CT1. It has a length equal to or more than ／ of the width W2 of CT2. The overlapping area OA has a length in the longitudinal direction (width direction dy) of the second contact area CT2 that is equal to or more than ２ of the width W1 of the contact area along the longitudinal direction of the second contact area CT2. I have. According to such an example, the contact region CT1 and the second contact region CT2 can overlap with a sufficient size, and excellent sealing performance can be imparted to the laminated secondary battery 1.

In the embodiment described above, the laminate exterior body 40 has the linear welded portion MJ1 to which the exterior material 41 arranged opposite is welded. The thickness at the welded portion MJ1 of the laminate exterior body 40 is a portion located between both end portions EP1 in both end portions EP in the longitudinal direction (drawing direction dx) of the welded portion MJ1 connected to the peripheral edge ce of the laminate exterior body 40. It is thicker than OP and MP. According to the laminate exterior body 40 having such a welded portion MJ1, the hermeticity of the accommodation space RS can be improved. Thereby, it is possible to effectively avoid the unexpected leakage of the electrolyte solution from the laminate exterior body 40 and improve the reliability of the laminate type secondary battery 1.

In the above-described embodiment, the total thickness of the sealant layer 45 at both end portions EP of the welded portion MJ1 of the laminate exterior body 40 is a certain portion located between both end portions EP of the welded portion MJ1 of the laminate exterior body 40. The total thickness of the sealant layer 45 in OP and MP is twice or more. According to the laminate exterior body 40 having such a welded portion MJ1, the hermeticity of the accommodation space RS can be more effectively improved.

In the above-described embodiment, the thickness of the laminated exterior body 40 at the welded portion MJ1 is maximum at both end portions EP. According to the laminate exterior body 40 having such a welded portion MJ1, the hermeticity of the accommodation space RS can be more effectively improved.

In the above-described embodiment, the laminate exterior body 40 extends linearly across the first welded portion MJ1 and has a linear second welded portion MJ2 to which the exterior material 41 disposed oppositely is welded. Is further provided. The thickness of the laminate exterior body 40 at the first welded portion MJ1 is larger than the overlapped portion OP intersecting the second welded portion MJ2, and the end portion EP located between the overlap portion OP and the peripheral edge ce of the laminate exterior body 40. In, it is thick. According to the laminate exterior body 40 having the first welded portion MJ1 and the second welded portion MJ2, the hermeticity of the accommodation space RS can be more effectively improved.

In the embodiment described above, the thickness at the end portion EP of the laminate exterior body 40 is twice or more the thickness at the overlapping portion OP of the laminate exterior body 40. According to the laminate exterior body 40 having the first welded portion MJ1 and the second welded portion MJ2, the hermeticity of the accommodation space RS can be more effectively improved.

Although the embodiments have been described with reference to specific examples, these specific examples are not intended to limit the embodiments. 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.

For example, in one specific example described above, an example is shown in which the laminate exterior body 40 has one folded exterior material 41, but is not limited thereto. The laminate exterior body 40 may include a first exterior material and a second exterior material that are arranged to face each other. In this example, when the laminate exterior body 40 has a rectangular shape in plan view, the accommodation space RS can be sealed by forming four welded portions on the laminate exterior body 40. Each welded portion can be configured similarly to the first welded portion MJ1 in the above-described example.

Hereinafter, the present invention will be described with reference to examples, but the following description does not limit the present invention.

Similarly to the above-described manufacturing method, first, the second welded portion MJ2 and the third welded portion MJ3 are connected to the laminated exterior body 40 in a state where the electrode body 5 is sandwiched by the laminated exterior body 40 obtained by folding one exterior material 41. Then, after injecting the electrolytic solution into the laminate exterior body 40, the first welded portion MJ1 was produced on the laminate exterior body 40, thereby producing the laminate type secondary battery 1. Conditions such as the heating temperature of the heat bar 51, the pressure at which the heat bar 51 presses the laminate exterior body 40, and the time during which the heat bar 51 presses the laminate exterior body 40 are the usual conditions used in the manufacture of the laminate type secondary battery 1. The heat bar 51 having a different overall length was used in the comparative example and the example under the conditions. In Comparative Examples and Examples, the conditions were the same except for the length of the heat bar.

よう As shown in FIG. 15, the length of the laminate exterior body 40 along the drawing direction dx was 509 mm. The second contact area CT2 with which the heat bar 51 is in contact when forming the second welded portion MJ2 has a width of 8 mm along the drawing direction dx, and is separated from the second edge e2 by 0.5 mm in the drawing direction dx. Then, it was separated by 0.5 mm in the width direction dy from the first edge e1. The third contact area CT3 with which the heat bar 51 is in contact when forming the third welded portion MJ3 has a width of 8 mm along the drawing direction dx and is separated from the third edge e3 by 0.5 mm in the drawing direction dx. Then, it was separated by 0.5 mm in the width direction dy from the first edge e1.

{Circle around (1)} The first contact area CT1 with which the heat bar 51 comes into contact when forming the first welded portion MJ1 was centered with the laminate exterior body 40 in the drawing direction dx. Further, the first contact area CT1 has a width of 8 mm along the width direction dy and is separated from the first edge e1 by 0.5 mm in the width direction dy. In Comparative Examples 1 and 2, the heat bar 51 having a length of 514 mm and 539 mm was used. Therefore, in Comparative Example 1 and Comparative Example 2, the first contact region CT1 has a length of 509 mm in the drawing direction dx, and the heat bar 51 is connected to the second edge e2 and the third edge e3 of the laminate exterior body 40. Was extending beyond. On the other hand, in Examples 1 to 3, the heat bars 51 having a length of 508 mm, 503 mm, and 498 mm were used, respectively. Therefore, in Examples 1 to 3, the first contact area CT1 has a length of 508 mm, 503 mm, and 498 mm along the drawing direction dx.

A large number of laminated secondary batteries 1 having the second welded portion MJ2 and the third welded portion MJ3 formed thereon are easily prepared, and the formation of the first welded portion MJ1 is continuously performed using the same heat bar 51 in each example. went. In each example, the number of shots (number of formations) at which the sealant material adhered to the heat bar 51 and the formation of the first welded portion MJ1 became difficult was confirmed.

では In Examples 1 to 3, the first welded portion MJ1 was formed 20,000 times, but the sealant material did not adhere to the heat bar 51. On the other hand, in Comparative Examples 1 and 2, the heat bar 51 needs to be cleaned every time the first welded portion MJ1 is formed ten times.

Claims

A method of manufacturing a laminate type secondary battery having a laminate exterior body formed using an exterior material including a metal layer and a sealant layer laminated on the metal layer, and an electrode body disposed in the laminate exterior body And
A step of welding the exterior material arranged oppositely by contacting a heat bar to a portion where the exterior material of the laminate exterior body that accommodates the electrode body is arranged oppositely,
The method for manufacturing a laminate type secondary battery, wherein the heat bar contacts a contact area located inside a peripheral portion of the laminate exterior body.
The method for manufacturing a laminated secondary battery according to claim 1, wherein the contact region is separated from the peripheral edge of the laminate exterior body by 0.5 mm or more.
Further comprising a step of contacting a heat bar with the second contact region of the laminate exterior body and welding an exterior material arranged opposite thereto,
The one edge in the longitudinal direction of the second contact region is located in the contact region, or the one edge in the longitudinal direction of the contact region is located in the second contact region, or 3. The method for producing a laminated secondary battery according to item 2.
The overlap region of the contact region and the second contact region has a length in the longitudinal direction of the contact region that is equal to or greater than 2/5 of the width of the second contact region along the longitudinal direction of the contact region. And
4. The laminate according to claim 3, wherein the overlapping region has a length in the longitudinal direction of the second contact region that is equal to or more than ／ of a width of the contact region along the longitudinal direction of the second contact region. 5. Manufacturing method of a rechargeable secondary battery.
Further comprising a step of contacting a heat bar with a third contact region of the laminate exterior body and welding an exterior material arranged opposite thereto;
The one edge in the longitudinal direction of the third contact region is located in the contact region, or the other edge in the longitudinal direction of the contact region is located in the third contact region. 5. The method for producing a laminate type secondary battery according to any one of 4.
The laminate exterior body has a rectangular shape in plan view,
The laminate type secondary battery according to claim 5, wherein the contact region, the second contact region, and the third contact region extend linearly along each of the three different edges of the rectangular shape. Production method.
A laminate exterior body formed using an exterior material including a metal layer and a sealant layer laminated on the metal layer,
Having a plurality of electrodes, and an electrode body housed in the laminate exterior body,
The laminate exterior body has a linear welded portion in which exterior materials arranged opposite to each other are welded,
A laminated secondary battery in which the thickness of the laminated exterior body at the welded portion is greater at both end portions in the longitudinal direction of the welded portion than at a portion located between the both end portions.
The laminated secondary battery according to claim 7, wherein the welded portion is connected to an edge of the laminate exterior body at the both end portions.
The total thickness of the sealant layer at the both end portions of the welded portion of the laminate exterior body is the total thickness of the sealant layer at a portion located between the both end portions of the welded portion of the laminate exterior body. The laminated secondary battery according to claim 7, wherein the secondary battery is at least twice as large as the above.
The laminated secondary battery according to any one of claims 7 to 9, wherein the thickness of the laminated exterior body at the welded portion is maximum at the both end portions.
The laminate exterior body further includes a linear second welded portion in which an exterior material that extends linearly and intersects with the welded portion and is disposed to face is welded,
The thickness of the laminate exterior body at the welded portion is thicker at an end located between the overlapped portion and the edge of the laminate exterior body than at an overlapped portion that intersects with the second welded portion. The laminated secondary battery according to any one of claims 7 to 10.
The laminated secondary battery according to claim 11, wherein the thickness of the laminate outer body at the end portion is at least twice the thickness of the laminate outer body at the overlapping portion.