JP2020072070A - Electrochemical cell - Google Patents

Abstract

To provide a laminate type electrochemical cell that can prevent falling of electrode terminal plates and has improved safety.SOLUTION: There is provided an electrochemical cell 1 comprising: an electrode body 2 in which a plurality of electrodes 10, 20 are stacked in a lamination direction; an exterior body 3 that is formed of a laminate film and accommodates the electrode body therein; electrode plates 50, 51 that are disposed between the electrode body and exterior body; electrode terminal plates 52, 53 that are fastened to principal surfaces of the electrode plates; and annular sealant films 54, 55 that weld the exterior body and the electrode plates to each other, in which the exterior body is formed with through holes 37a, 46a that expose at least part of the electrode terminal plates to the outside, and at least one of the members: the electrode terminal plates and sealant films are provided with regulating pieces 60, 61 that are formed to project toward the other members and overlap in a lamination direction with respect to the other members, and regulate displacement of the electrode terminal plates toward the through holes.SELECTED DRAWING: Figure 4

Description

  The present invention relates to electrochemical cells.

  Electrochemical cells such as non-aqueous electrolyte secondary batteries and electric double layer capacitors are widely used as power sources for various devices. In recent years, as this type of electrochemical cell, a so-called laminate-type electrochemical cell in which a laminate film is used for an exterior body that houses an electrode body is known. This laminate-type electrochemical cell is known as an electrochemical cell that is small in size, has a high degree of freedom in shape, and has a higher capacity.

For example, Patent Document 1 below includes an electrode body, a first laminate member and a second laminate member, and an exterior body that houses the electrode body between the first laminate member and the second laminate member. An electrochemical cell is disclosed.
Each of the first laminate member and the second laminate member is a laminated film including a metal layer and an inner resin layer and an outer resin layer laminated on both surfaces of the metal layer. Through holes are formed in the first laminate member and the second laminate member to expose the electrode terminal plate (nickel plate) that functions as an external electrode terminal to the outside. The electrode terminal plate is disposed inside the through hole while being welded to the electrode plate. The electrode plate is heat-sealed to the inner resin layer via a sealant film arranged between the electrode plate and the inner resin layer. The sealant film is formed in a ring shape that surrounds the electrode terminal plate welded to the electrode plate from the outside.

Japanese Patent No. 6284248

However, in the above-described conventional laminate type electrochemical cell, the electrode terminal plate is exposed to the outside through the through hole in a state where the electrode terminal plate is surrounded by the sealant film and is only welded to the electrode plate. Therefore, if the electrode terminal plate is peeled off from the electrode plate for some reason, such as an external impact or the aging of the welded portion, the electrode terminal plate will fall out through the through hole (peeling off). ), And there was room for improvement.
In particular, when the dropped electrode terminal plate comes into contact with, for example, an electronic circuit arranged around the electrochemical cell, a short circuit (circuit short circuit) may be caused. Therefore, it is desired to prevent the electrode terminal plate from falling off.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a laminate-type electrochemical cell capable of preventing the electrode terminal plate from falling off and improving safety. ..

(1) The electrochemical cell according to the present invention is formed of an electrode body having a plurality of electrodes laminated in the laminating direction, a laminate film having a metal layer and a resin layer covering both surfaces of the metal layer, An exterior body that houses an electrode body therein, an electrode plate that is integrally connected to the electrode body and that is disposed between the electrode body and the exterior body in the stacking direction, and the exterior body of the electrode plates. An electrode terminal plate fixed to the main surface facing the body side, and arranged between the electrode plate and the exterior body in a state of enclosing the electrode terminal plate, and welding the exterior body and the electrode plate to each other. An annular sealant film is provided, and a through hole that exposes at least a part of the electrode terminal plate to the outside is formed in the exterior body, and any one of the electrode terminal plate and the sealant film is formed. Has A restricting piece that is formed so as to project with respect to one of the members and overlaps with the other member in the stacking direction and restricts the displacement of the electrode terminal plate toward the through hole side is provided. It is characterized by

  According to the electrochemical cell of the present invention, since the electrode terminal plate fixed to the electrode plate is exposed to the outside through the through hole, the electrode terminal plate can be used as an external connection terminal. Particularly, the electrode terminal plate is not only fixed to the electrode plate, but also the displacement toward the through hole side is regulated by the regulation piece. Thus, even if the adhesion strength between the electrode plate and the electrode terminal plate is lowered due to some reason such as impact from the outside, the electrode terminal plate can be prevented from peeling off from the electrode plate. it can. Therefore, it is possible to prevent the electrode terminal plate from falling out through the through hole, and it is possible to provide a laminate type electrochemical cell with improved safety.

(2) A plurality of the restriction pieces may be formed at intervals in the circumferential direction of the sealant film.

  In this case, since a plurality of regulating pieces are formed, even if the electrode terminal plate is displaced toward the through hole side, the displacement can be regulated at a plurality of places. Therefore, the electrode terminal plate can be more effectively prevented from falling off.

(3) The restriction piece may be formed in an annular shape along the circumferential direction of the sealant film.

  In this case, since the restricting piece is formed in an annular shape, even if the electrode terminal plate is displaced toward the through hole side, the displacement should be uniformly regulated over the entire circumference of the electrode terminal plate. You can Therefore, it is possible to more effectively prevent the electrode terminal plate from falling off.

(4) The regulation piece is integrally formed with the electrode terminal plate so as to project from the outer peripheral edge portion of the electrode terminal plate toward the sealant film, and between the sealant film and the electrode plate. It may be sandwiched in the stacking direction.

  In this case, the restricting piece integrally formed with the electrode terminal plate is inserted between the sealant film and the electrode plate and sandwiched between them in the stacking direction. Thereby, the electrode terminal plate can be pressed from the through hole side through the restriction piece by using the sealant film that welds the electrode plate and the outer casing together. Therefore, the electrode terminal plate is less likely to be separated from the electrode plate, and the electrode terminal plate can be more effectively prevented from falling off.

(5) The sealant film may be formed to have an inner diameter smaller than the inner diameter of the through hole, and the electrode terminal plate may be formed to be thinner than the sealant film.

  In this case, since the electrode terminal plate is formed thinner than the sealant film and the inner diameter of the sealant film is formed smaller than the inner diameter of the through hole, a part of the sealant film (inner peripheral edge side) The sealant film can be protruded inside the through hole, and a part of the sealant film can be arranged between the electrode terminal plate and the through hole. Therefore, it is possible to prevent the metal layer of the exterior body exposed at the inner end surface of the through hole from coming into contact with the electrode terminal plate for some reason by utilizing a part of the sealant film. Therefore, the metal layer can be protected and the metal layer can be prevented from being charged with a potential. Therefore, the inconvenience caused by the electric potential of the metal layer is unlikely to occur in the outer package, and the quality of the outer package can be maintained for a long period of time.

  According to the present invention, it is possible to prevent the electrode terminal plate from falling off, and to obtain a laminate-type electrochemical cell with improved safety.

1 is a perspective view showing an embodiment of a secondary battery (electrochemical cell) according to the present invention. FIG. 2 is a vertical cross-sectional view of the secondary battery taken along the line AA shown in FIG. 1. FIG. 3 is a vertical cross-sectional view of a secondary battery in which a portion surrounded by a virtual circle B shown in FIG. 2 is enlarged. FIG. 3 is an exploded perspective view of the secondary battery shown in FIG. 2. FIG. 5 is a vertical cross-sectional view of the electrode body taken along the line C-C shown in FIG. 4. FIG. 6 is a development view of the positive electrode shown in FIG. 5 before winding. FIG. 6 is a development view of the negative electrode shown in FIG. 5 before winding. It is a figure which shows the state which has begun to wind the positive electrode and negative electrode which are shown in FIG. 5 and FIG. It is sectional drawing which shows the relationship of the exterior body shown in FIG. 2, a 1st sealant film, a 1st electrode plate, a 1st electrode terminal plate, and a 1st control piece. It is a perspective view which shows the relationship of the 1st sealant film, the 1st electrode terminal board, and the 1st control piece shown in FIG. It is a figure showing the modification concerning the present invention, and is a perspective view showing the relation of the 1st sealant film, the 1st electrode terminal board, and the 1st control piece. It is a top view which shows the relationship of the 1st sealant film, the 1st electrode terminal board, and the 1st control piece shown in FIG. It is a figure showing another modification concerning the present invention, and is a perspective view showing the relation of the 1st sealant film, the 1st electrode terminal board, and the 1st control piece. It is a top view which shows the relationship of the 1st sealant film, the 1st electrode terminal board, and the 1st control piece shown in FIG. It is a figure which shows the modification concerning this invention, Comprising: It is a perspective view of a secondary battery. It is a perspective view which shows an example of the electrode body in the secondary battery shown in FIG.

  Embodiments of an electrochemical cell according to the present invention will be described below with reference to the drawings. In the present embodiment, as the electrochemical cell, a lithium ion secondary battery (hereinafter, simply referred to as a secondary battery), which is a kind of non-aqueous electrolyte secondary battery, will be described as an example.

  As shown in FIGS. 1 to 4, the secondary battery 1 of the present embodiment is a so-called button-type battery and has a plurality of electrodes stacked in the stacking direction Z, that is, a positive electrode 10 and a negative electrode 20. The electrode body 2 and an exterior body 3 formed of a laminated film and containing the electrode body 2 therein are mainly provided. 2 and 3, the electrode body 2 is shown in a simplified manner.

As shown in FIGS. 4 and 5, the electrode body 2 is a so-called laminated electrode in which the positive electrode 10 and the negative electrode 20 are laminated with a separator (not shown) interposed therebetween.
In this embodiment, a case where the positive electrode 10 and the negative electrode 20 are stacked in the vertical direction will be described as an example so that the stacking direction Z is the vertical direction. Further, an axis extending through the center of the electrode body 2 along the stacking direction Z is referred to as a central axis O, and in a plan view viewed from the central axis O direction, a direction intersecting with the central axis O is a radial direction, and a direction around the central axis O. The direction that goes around is called the circumferential direction.

  The electrode body 2 is formed to have a circular outer shape in a plan view. However, the outer shape of the electrode body 2 is not limited to this case, and may be another shape such as an elliptical shape, an elliptical shape, or a rhombic shape, and may be appropriately changed.

  The positive electrode 10 and the negative electrode 20 of the present embodiment are alternately laminated by being wound with a separator in between. However, the present invention is not limited to this case, and for example, the positive electrode 10 and the negative electrode 20 may be folded in a zigzag shape in directions intersecting with each other so that they are alternately stacked. Further, it may be a so-called pellet type electrode body in which the positive electrode 10 and the negative electrode 20 are provided on both surfaces of the separator.

The structure of the electrode body 2 will be briefly described.
As shown in FIG. 6, the positive electrode 10 is formed on both surfaces of the positive electrode current collector 11 and the positive electrode current collector 11 that is formed in a strip shape and extends along the first direction L1 in the expanded state before winding. And a positive electrode active material layer (not shown).

  The positive electrode current collector 11 is formed in a thin sheet shape with a metal material such as aluminum or stainless steel, and includes a plurality of positive electrode main bodies 12 and a plurality of positive electrode connecting pieces 13. The positive electrode main body 12 is formed in a disc shape, and is arranged at intervals so as to be arranged in a line in the first direction L1. In the illustrated example, the number of positive electrode main bodies 12 is eight. However, the number of the positive electrode main bodies 12 is not limited to eight and may be changed as appropriate.

  The positive electrode connecting piece 13 is arranged between the positive electrode main bodies 12 adjacent to each other in the first direction L1, and connects the adjacent positive electrode main bodies 12 to each other. Therefore, in the illustrated example, the number of the positive electrode connecting pieces 13 is seven. The positive electrode connecting piece 13 is formed so that the length along the second direction L2 orthogonal to the first direction L1 in plan view is shorter than the length along the second direction L2 of the positive electrode main body 12.

A positive electrode terminal tab 14 is formed on the positive electrode main body 12 located at one end position in the first direction L1 among the plurality of positive electrode main bodies 12 so as to further extend outward in the first direction L1. ..
In the present embodiment, the positive electrode main body 12 located at the other end position in the first direction L1 is referred to as the first-stage positive electrode main body 12 and is directed toward the positive electrode main body 12 on which the positive electrode terminal tab 14 is formed. Are sequentially referred to as the second, third, fourth, fifth, sixth, seventh and eighth positive electrode bodies 12. Therefore, the positive electrode main body 12 on which the positive electrode terminal tab 14 is formed corresponds to the eighth-stage positive electrode main body 12.

The positive electrode active material layer is formed on both surfaces of the positive electrode current collector 11 excluding the positive electrode terminal tab 14. The positive electrode active material layer contains a positive electrode active material, a conductive auxiliary agent, a binder, a thickener, and the like, and is formed of, for example, a composite metal oxide such as lithium cobalt oxide and lithium nickel oxide.
Examples of the conductive aid include carbon blacks, carbon materials, and fine metal powders. Examples of the binder include resin materials such as polyvinylidene fluoride (PVDF), styrene butadiene rubber (SBR) and polytetrafluoroethylene (PTFE). Examples of the thickener include resin materials such as carboxymethyl cellulose (CMC).

As shown in FIG. 7, the negative electrode 20 is formed on both surfaces of the negative electrode current collector 21 and the negative electrode current collector 21 that is formed in a strip shape and extends along the first direction L1 in the expanded state before winding. And a negative electrode active material layer (not shown).
The negative electrode current collector 21 is formed in a thin sheet shape with a metal material such as copper, nickel, and stainless, and includes a plurality of negative electrode bodies 22 and a plurality of negative electrode connection pieces 23. The negative electrode body 22 is formed in a disk shape like the positive electrode body 12, and is arranged at intervals so as to be arranged in a line in the first direction L1. In the illustrated example, the number of the negative electrode bodies 22 is eight, which corresponds to the number of the positive electrode bodies 12. However, the number of the negative electrode main bodies 22 is not limited to eight, and may be appropriately changed according to the number of the positive electrode main bodies 12.

  The negative electrode connecting piece 23 is arranged between the negative electrode main bodies 22 adjacent to each other in the first direction L1, and connects the adjacent negative electrode main bodies 22 to each other. Therefore, in the illustrated example, the number of the negative electrode connecting pieces 23 is seven. The negative electrode connecting piece 23 is formed so that the length along the second direction L2 orthogonal to the first direction L1 in plan view is shorter than the length along the second direction L2 of the negative electrode body 22.

A negative electrode terminal tab 24 is formed on the negative electrode body 22 located at one end position in the first direction L1 among the plurality of negative electrode bodies 22 so as to further extend outward in the first direction L1. ..
In the present embodiment, the negative electrode body 22 located at the other end position in the first direction L1 is referred to as the first-stage negative electrode body 22 and is directed toward the negative electrode body 22 having the negative electrode terminal tab 24 formed thereon. Are sequentially referred to as the second, third, fourth, fifth, sixth, seventh and eighth negative electrode bodies 22. Therefore, the negative electrode main body 22 on which the negative electrode terminal tab 24 is formed corresponds to the eighth-stage negative electrode main body 22.

  The negative electrode 20 configured as described above has a similar outer diameter shape to the outer diameter shape of the positive electrode 10 described above. However, the outer size of the positive electrode 10 is formed slightly smaller (smaller than the outer size) of the negative electrode 20.

The negative electrode active material layer is formed on both surfaces of the negative electrode current collector 21 excluding the negative electrode terminal tab 24. The negative electrode active material layer contains a negative electrode active material, a conductive auxiliary agent, a binder, a thickener, and the like, and is formed of a carbon material such as graphite.
Examples of the conductive aid include carbon blacks, carbon materials, and fine metal powders. Examples of the binder include resin materials such as polyvinylidene fluoride (PVDF), styrene butadiene rubber (SBR) and polytetrafluoroethylene (PTFE). Examples of the thickener include resin materials such as carboxymethyl cellulose (CMC).

The positive electrode 10 and the negative electrode 20 configured as described above are alternately stacked by being wound with the separator interposed therebetween as described above.
Specifically, as shown in FIG. 8, the positive electrode 10 and the negative electrode 20 are arranged along the first direction L1 such that the positive electrode terminal tab 14 and the negative electrode terminal tab 24 are arranged on the opposite sides. The first-stage positive electrode main body 12 and the first-stage negative electrode main body 22 are superposed. Then, the positive electrode body 10 and the negative electrode body 20 are repeatedly wound in the same direction starting from the first-stage positive electrode body 12 and the negative electrode body 22 that are stacked on each other. Thereby, the positive electrode main body 12 and the negative electrode main body 22 can be stacked in the stacking direction Z so as to be alternately stacked, and the electrode body 2 shown in FIG. 5 can be obtained. Note that the separator is not shown in FIGS. 5 and 8.

In the electrode body 2 obtained by the above-described winding, as shown in FIG. 5, the positive electrode main body 12 of the eighth stage on which the positive electrode terminal tab 14 is formed is located at the uppermost stage, and the negative electrode terminal tab 24 is formed. The eighth-stage negative electrode body 22 is located at the bottom. Therefore, the electrode body 2 is accommodated in the exterior body 3 with the positive electrode terminal tab 14 facing upward and the negative electrode terminal tab 24 facing downward.
Note that in the electrode body 2 shown in FIG. 5, focusing on the positive electrode 10, from the upper side to the lower side, the eighth stage, the sixth stage, the fourth stage, the second stage, the first stage, the The positive electrode 10 is wound such that the positive electrode bodies 12 are arranged in parallel in the stacking direction Z in the order of the third, fifth, and seventh stages. On the other hand, focusing on the negative electrode 20, the seventh stage, the fifth stage, the third stage, the first stage, the second stage, the fourth stage, the sixth stage from the top to the bottom. The negative electrode 20 is wound such that the negative electrode bodies 22 are arranged in parallel to each other in the stacking direction Z in the order of the eighth and eighth steps.

  As shown in FIGS. 1 to 4, the outer package 3 includes a first laminate member 30 and a second laminate member 40 which are formed of a laminate film and are stacked in the stacking direction Z with the electrode body 2 interposed therebetween. There is. Thereby, the exterior body 3 accommodates the electrode body 2 in a sealed state between the first laminate member 30 and the second laminate member 40. An electrolyte solution (not shown) is filled between the first laminating member 30 and the second laminating member 40.

  The first laminate member 30 is a member that covers the electrode body 2 from above, and includes a metal layer 31, an inner resin layer (resin layer according to the present invention) 32 that covers both surfaces of the metal layer 31, and an outer resin layer (main). And a resin layer 33 according to the invention. The inner resin layer 32 and the outer resin layer 33 are densely bonded to both surfaces of the metal layer 31 via a bonding layer (not shown) by, for example, heat fusion or adhesion. 1, 2, and 4, the metal layer 31, the inner resin layer 32, and the outer resin layer 33 are not shown.

The metal layer 31 is formed of a metal material suitable for blocking outside air or water vapor, such as stainless steel or aluminum.
The inner resin layer 32 functions as an inner layer of the exterior body 3, and is formed by using a thermoplastic resin such as polyolefin such as polyethylene or polypropylene. Examples of the polyolefin include high-pressure low-density polyethylene (LDPE), low-pressure high-density polyethylene (HDPE), inflation polypropylene (IPP) film, non-oriented polypropylene (CPP) film, biaxially oriented polypropylene (OPP) film, linear Any material of short-chain branched polyethylene (L-LDPE, metallocene catalyst specification) can be used. Polypropylene resin is particularly preferable.
The outer resin layer 33 functions as an outer layer of the exterior body 3, and is formed using, for example, the above-mentioned polyolefin, polyester such as polyethylene terephthalate, nylon, or the like.

The first laminate member 30 includes a housing portion 35 having a topped tubular shape and a first surrounding tubular portion 38, and is arranged coaxially with the central axis O. The accommodating portion 35 includes a cylindrical peripheral wall portion 36 that surrounds the electrode body 2 from the outside in the radial direction, and a top wall portion 37 that closes the upper end opening of the peripheral wall portion 36 and covers the electrode body 2 from above.
The first surrounding tubular portion 38 is formed in a tubular shape that surrounds the peripheral wall portion 36 from the outside in the radial direction. The lower end portion of the first surrounding cylinder portion 38 is formed so as to be integrally connected to the lower end portion of the peripheral wall portion 36. That is, the first surrounding cylinder portion 38 is formed by folding the peripheral wall portion 36 upward. An annular space that opens upward is formed between the first surrounding cylinder 38 and the peripheral wall 36.

The second laminate member 40 is a member that covers the electrode body 2 from below, and includes a metal layer 41, an inner resin layer (resin layer according to the present invention) 42 and an outer resin layer (which cover both surfaces of the metal layer 41). Resin layer) 43 according to the present invention. The inner resin layer 42 and the outer resin layer 43 are densely bonded to both surfaces of the metal layer 41 via a bonding layer (not shown) by, for example, heat fusion or adhesion.
The materials of the metal layer 41, the inner resin layer 42, and the outer resin layer 43 are the same as those of the metal layer 31, the inner resin layer 32, and the outer resin layer 33 of the first laminate member 30. The metal layer 41, the inner resin layer 42, and the outer resin layer 43 are not shown in FIGS. 1, 2, and 4.

  The second laminating member 40 closes the tubular second surrounding tubular portion 45 that further surrounds the first surrounding tubular portion 38 from the outer side in the radial direction, and the lower end opening of the second surrounding tubular portion 45, and also closes the electrode body 2. It is formed in a bottomed cylindrical shape having a bottom wall portion 46 that covers from below, and is arranged coaxially with the central axis O.

  In the first laminating member 30 and the second laminating member 40 configured as described above, the first enclosing tube portion 38 and the second enclosing tube portion 45 are thermally welded to each other, so that the electrode body 2 and the electrolyte solution are removed. It is assembled in a sealed state inside. Specifically, the inner resin layer 32 in the first surrounding cylinder portion 38 and the inner resin layers 42 in the second surrounding cylinder portion 45 are thermally welded to each other.

Further, the secondary battery 1 of the present embodiment has a first electrode plate (electrode plate according to the present invention) 50 and a second electrode plate (electrode plate according to the present invention) as shown in FIGS. 2, 4 and 9. 51, a first electrode terminal plate (electrode terminal plate according to the present invention) 52, a second electrode terminal plate (electrode terminal plate according to the present invention) 53, a first sealant film (sealant film according to the present invention) 54, A second sealant film (sealant film according to the present invention) 55.
The first electrode plate 50, the second electrode plate 51, the first electrode terminal plate 52, the second electrode terminal plate 53, the first sealant film 54 and the second sealant film 55 are provided inside the exterior body 3 together with the electrode body 2. It is housed.

  The first electrode plate 50, the first electrode terminal plate 52, and the first sealant film 54 are arranged between the electrode body 2 and the top wall portion 37 of the first laminate member 30. The second electrode plate 51, the second electrode terminal plate 53, and the second sealant film 55 are arranged between the electrode body 2 and the bottom wall portion 46 of the second laminating member 40.

The first electrode plate 50 is formed in a circular shape in plan view and is integrally connected to the positive electrode 10 of the electrode body 2. The first electrode plate 50 is formed of a metal material such as aluminum or stainless steel with a diameter smaller than that of the electrode body 2, and is arranged coaxially with the central axis O.
The first electrode plate 50 is arranged so as to overlap the positive electrode main body 12 in the eighth stage of the positive electrode 10 in the electrode body 2, and the positive electrode terminal tab 14 is provided on the lower surface facing the electrode body 2 side by, for example, ultrasonic welding. It is welded by. Thereby, the first electrode plate 50 is integrally connected to the positive electrode 10.

  The first electrode terminal plate 52 is formed of a metal material such as nickel into a circular shape in plan view having a diameter smaller than that of the first electrode plate 50, and the upper surface of the first electrode plate 50 facing the first laminate member 30 side. It is arranged so as to overlap (the main surface according to the present invention). The first electrode terminal plate 52 is integrally fixed to the upper surface of the first electrode plate 50 by welding such as resistance welding. The first electrode terminal plate 52 functions as an external connection terminal of the positive electrode 10.

  A first through hole (a through hole according to the present invention) 37a that exposes at least a part of the first electrode terminal plate 52 to the outside is formed in the top wall portion 37 of the first laminate member 30. The first through hole 37a is formed so as to vertically penetrate the central portion of the top wall portion 37, and is formed coaxially with the central axis O. The first through hole 37a is formed in a circular shape in plan view, and its inner diameter is smaller than the outer diameter of the first electrode plate 50, for example.

The first sealant film 54 is formed in an annular shape that surrounds the first electrode terminal plate 52 from the outside in the radial direction, and surrounds the first electrode terminal plate 52, and the top wall of the first electrode terminal plate 52 and the first laminating member 30. It is disposed coaxially with the central axis O between the portion 37 and the portion 37.
The outer shape of the first sealant film 54 is circular in plan view, and the first sealant film 54 is formed in a ring shape with a first film through hole 54a in plan view having a circular shape in plan view. However, the outer shape of the first sealant film 54 does not need to be formed in a circular shape in plan view, and may be formed in an elliptical shape or a polygonal shape in plan view, for example.

The first sealant film 54 is heat-welded to the inner resin layer 32 of the top wall portion 37 of the first laminate member 30 and the upper surface of the first electrode plate 50, respectively. As a result, the first electrode plate 50 is heat-welded to the top wall portion 37 of the first laminate member 30 via the first sealant film 54.
The first sealant film 54 is formed of, for example, a thermoplastic resin such as polyethylene or polypropylene of polyolefin, or a nonwoven fabric made of polypropylene.

  The first sealant film 54 is formed such that the inner diameter of the first film through hole 54 a is smaller than the inner diameter of the first through hole 37 a formed in the top wall portion 37 of the first laminating member 30. As a result, the inner peripheral edge portion 54b side of the first sealant film 54 is arranged so as to protrude inside the first through hole 37a. The first electrode terminal plate 52 is formed thinner than the first sealant film 54.

  Since the first electrode plate 50, the first electrode terminal plate 52, and the first sealant film 54 are formed as described above, the first electrode terminal plate 52 is upwardly moved through the first film through hole 54a and the first through hole 37a. Is exposed to. In the illustrated example, the outer diameter of the first electrode terminal plate 52 is the same as the inner diameter of the first film through hole 54a. As a result, the entire surface of the first electrode terminal plate 52 is exposed upward.

  By the way, one of the first electrode terminal plate 52 and the first sealant film 54 is formed so as to project from the other member, and is formed in the stacking direction Z with respect to the other member. A first regulation piece (regulation piece according to the present invention) 60 that overlaps and regulates the displacement of the first electrode terminal plate 52 toward the first through hole 37a side is provided.

Specifically, as shown in FIG. 2, FIG. 4, FIG. 9 and FIG. 10, the first restricting piece 60 extends radially outward from the outer peripheral edge portion of the first electrode terminal plate 52 (first sealant). It is integrally formed with the first electrode terminal plate 52 so as to project (toward the film 54), and is formed in an annular shape over the entire circumference of the first electrode terminal plate 52. The first restriction piece 60 is inserted between the first sealant film 54 and the first electrode plate 50 and sandwiched in the stacking direction Z.
The overall outer diameter of the first electrode terminal plate 52 and the first restriction piece 60 is set to be equal to the inner diameter of the first through hole 37a. As a result, the first restriction piece 60 is sandwiched between the first electrode plate 50 and the inner peripheral edge portion 54b of the first sealant film 54 that is arranged so as to project inside the first through hole 37a. ..

  As shown in FIGS. 2 and 4, the second electrode plate 51, the second electrode terminal plate 53, and the second sealant film 55 are the same as the above-described first electrode plate 50, first electrode terminal plate 52, and first sealant film 54. Formed similarly to and arranged similarly.

  The second electrode plate 51 is formed in a circular shape in plan view and is integrally connected to the negative electrode 20 of the electrode body 2. The second electrode plate 51 is formed of a metal material such as copper with a diameter smaller than that of the electrode body 2, and is arranged coaxially with the central axis O. The second electrode plate 51 is arranged so as to overlap the negative electrode main body 22 of the eighth electrode of the negative electrode 20 in the electrode body 2, and the negative electrode terminal tab 24 is provided on the upper surface facing the electrode body 2 side by, for example, ultrasonic welding. It is welded by. As a result, the second electrode plate 51 is integrally connected to the negative electrode 20.

  The second electrode terminal plate 53 is formed of a metal material such as nickel into a circular shape in plan view having a diameter smaller than that of the second electrode plate 51, and the lower surface of the second electrode plate 51 facing the second laminate member 40 side. (Main surface according to the present invention). The second electrode terminal plate 53 is integrally fixed to the lower surface of the second electrode plate 51 by welding such as resistance welding. The second electrode terminal plate 53 functions as a negative electrode external connection terminal.

  A second through hole (a through hole according to the present invention) 46a that exposes at least a part of the second electrode terminal plate 53 to the outside is formed in the bottom wall portion 46 of the second laminate member 40. The second through hole 46a is formed so as to vertically penetrate the central portion of the bottom wall portion 46, and is formed coaxially with the central axis O. The second through hole 46 a is formed in a circular shape in plan view, and its inner diameter is smaller than the outer diameter of the second electrode plate 51, for example.

The second sealant film 55 is formed in an annular shape that surrounds the second electrode terminal plate 53 from the outside in the radial direction, and surrounds the second electrode terminal plate 53, and the bottom wall of the second electrode terminal plate 53 and the second laminating member 40. It is arranged coaxially with the central axis O between the portion 46 and the portion 46.
The second sealant film 55 is formed in a ring shape having an outer shape formed in a circular shape in a plan view and a second film through hole 55a formed in a circular shape in a plan view at the center thereof. However, the outer shape of the second sealant film 55 does not need to be formed in a circular shape in plan view, and may be formed in an elliptical shape or a polygonal shape in plan view, for example.

The second sealant film 55 is heat-welded to the inner resin layer 42 of the bottom wall portion 46 of the second laminate member 40 and the lower surface of the second electrode plate 51, respectively. As a result, the second electrode plate 51 is heat-welded to the bottom wall portion 46 of the second laminate member 40 via the second sealant film 55.
The second sealant film 55 is formed of, for example, a thermoplastic resin such as polyethylene or polypropylene of polyolefin, or a nonwoven fabric made of polypropylene, like the first sealant film 54.

  The second sealant film 55 is formed such that the inner diameter of the second film through hole 55a is smaller than the inner diameter of the second through hole 46a formed in the bottom wall portion 46 of the second laminating member 40. As a result, the inner peripheral edge portion 55b side of the second sealant film 55 is arranged so as to project inside the second through hole 46a. The second electrode terminal plate 53 is formed thinner than the second sealant film 55.

  Since the second electrode plate 51, the second electrode terminal plate 53, and the second sealant film 55 are formed as described above, the second electrode terminal plate 53 is downwardly moved through the second film through hole 55a and the second through hole 46a. Is exposed to. In the illustrated example, the outer diameter of the second electrode terminal plate 53 is the same as the inner diameter of the second film through hole 55a. As a result, the entire surface of the second electrode terminal plate 53 is exposed downward.

  By the way, one of the second electrode terminal plate 53 and the second sealant film 55 is formed so as to project from the other member, and in the stacking direction Z with respect to the other member. A second regulation piece (regulation piece according to the present invention) 61 that overlaps and regulates the displacement of the second electrode terminal plate 53 toward the second through hole 46a side is provided.

Specifically, the second restricting piece 61 projects from the outer peripheral edge of the second electrode terminal plate 53 toward the outer side in the radial direction (toward the second sealant film 55). Is integrally formed with the second electrode terminal plate 53, and is formed in a ring shape over the entire circumference of the second electrode terminal plate 53. The second restricting piece 61 is inserted between the second sealant film 55 and the second electrode plate 51 and is sandwiched in the stacking direction Z.
The entire outer diameter of the second electrode terminal plate 53 and the second restriction piece 61 is set to be equal to the inner diameter of the second through hole 46a. As a result, the second restriction piece 61 is sandwiched between the second electrode plate 51 and the inner peripheral edge portion 55b of the second sealant film 55 that is arranged so as to project inside the second through hole 46a. ..

(Operation of secondary battery)
According to the secondary battery 1 configured as described above, as shown in FIGS. 2 and 4, the first electrode terminal plate 52 fixed to the first electrode plate 50 is exposed upward, and Since the second electrode terminal plate 53 fixed to the two-electrode plate 51 is exposed downward, the first electrode terminal plate 52 and the second electrode terminal plate 53 can function as external connection terminals, respectively. it can. Thereby, the secondary battery 1 can be used by utilizing the first electrode terminal plate 52 and the second electrode terminal plate 53.

Particularly, the first electrode terminal plate 52 is not only fixed to the first electrode plate 50, but also the displacement toward the first through hole 37a side is regulated by the first regulation piece 60. As a result, even if the adhesion strength between the first electrode plate 50 and the first electrode terminal plate 52 is lowered due to some reason such as an impact from the outside, the first electrode terminal plate 52 does not work. It can be prevented from peeling from 50. Therefore, it is possible to prevent the first electrode terminal plate 52 from falling out through the first through hole 37a.
This also applies to the second electrode terminal plate 53, and the second restricting piece 61 can be used to prevent the second electrode terminal plate 53 from falling out through the second through hole 46a. ..

From the above, it is possible to obtain the laminate type secondary battery 1 in which both the first electrode terminal plate 52 and the second electrode terminal plate 53 are less likely to fall off and the safety is improved.
In addition, since it is possible to prevent the first electrode terminal plate 52 and the second electrode terminal plate 53 from falling off by using the first restriction piece 60 and the second restriction piece 61, for example, the first electrode terminal board 52 and the second electrode terminal board 52 The electrode terminal plate 53 may be fixed by adhesion using a conductive adhesive or the like instead of welding. In any case, the first electrode terminal plate 52 and the second electrode terminal plate 53 may be fixed to the first electrode plate 50 and the second electrode plate 51 by welding, adhesion, or another method.

Moreover, since the first restriction piece 60 enters between the first sealant film 54 and the first electrode plate 50 and is sandwiched between the two, the first electrode plate 50 and the first laminate member 30 are welded to each other. It is possible to press the first electrode terminal plate 52 from the first through hole 37a side via the first restriction piece 60 by using the first sealant film 54 that is formed. Therefore, the first electrode terminal plate 52 becomes more difficult to peel off from the first electrode plate 50, and the falling of the first electrode terminal plate 52 can be prevented more effectively.
In addition, since the first restricting piece 60 is formed in an annular shape over the entire circumference of the first electrode terminal plate 52, even if the first electrode terminal plate 52 tries to be displaced toward the first through hole 37a side, The displacement can be uniformly regulated over the entire circumference of the first electrode terminal plate 52 without deviation. Therefore, it is possible to more effectively prevent the first electrode terminal plate 52 from falling off.

  In addition, since the above-described operational effect can be similarly exerted on the second restriction piece 61, it is possible to more effectively restrict the second electrode terminal plate 53 from falling off.

Further, since the first electrode terminal plate 52 is formed thinner than the first sealant film 54, and the inner peripheral edge portion 54b side of the first sealant film 54 is projected to the inside of the first through hole 37a. It is possible to prevent the metal layer 31 of the first laminate member 30 exposed on the inner surface of the first through hole 37a from coming into contact with the first electrode terminal plate 52 for some reason. This also applies to the second sealant film 55, and it is possible to prevent the metal layer 41 of the second laminate member 40 and the second electrode terminal plate 53 from coming into contact with each other for some reason.
Therefore, both the metal layer 31 of the first laminating member 30 and the metal layer 41 of the second laminating member 40 can be protected. For example, a disadvantage caused by the metal layers 31 and 41 having a potential is the exterior body. 3 can be prevented. Therefore, the quality of the exterior body 3 can be maintained for a long period of time.

  Further, in the above-described embodiment, the first sealant film 54 is formed larger than the first electrode plate 50, and the second sealant film 55 is formed larger than the second electrode plate 51. It is possible to prevent the second electrode plate 51 from coming into direct contact with the exterior body 3. Therefore, also in this respect, the quality of the outer package 3 can be maintained.

  Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. The embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. The embodiments and the modifications thereof include, for example, those that can be easily conceived by those skilled in the art, those that are substantially the same, those that are within the equivalent range, and the like.

For example, although the second electrode plate 51 is made of copper in the above embodiment, it may be made of nickel, for example. In this case, the second electrode terminal plate 53 can be omitted.
That is, on the negative electrode side, the electrode terminal plate is not always essential, and may not be provided. In this case, the second electrode plate 51 itself can function as an external connection terminal on the negative electrode side.

Furthermore, in the above embodiment, the first restriction piece 60 is formed in a ring shape over the entire circumference of the first electrode terminal plate 52, but the present invention is not limited to this case. For example, as shown in FIGS. 11 and 12, a plurality of first restricting pieces 60 protrude outward from the outer peripheral edge portion of the first electrode terminal plate 52 in the radial direction and are spaced apart in the circumferential direction (for example, 4 pieces). It may be formed.
In this case, the number of the first restriction pieces 60 is not limited to four, and may be, for example, two to three, five or more, or even one.
Even when configured as shown in FIG. 11 and FIG. 12, similar operational effects can be achieved. Note that this point also applies to the second restricting piece 61.

Further, in the above embodiment, the first restriction piece 60 is formed on the first electrode terminal plate 52, but the present invention is not limited to this case, and it may be formed on the first sealant film 54 side.
For example, as shown in FIGS. 13 and 14, the first restricting piece 60 is formed so as to protrude inward in the radial direction from the inner peripheral edge portion 54b of the first sealant film 54, and is spaced apart in the circumferential direction. A plurality of them may be formed apart from each other. The first restriction piece 60 is formed so as to overlap the upper surface of the first electrode terminal plate 52.
Even in the case of such a configuration, the first restricting piece 60 can be used to press the first electrode terminal plate 52 from above, so that the first electrode terminal plate 52 is located on the first through hole 37a side. The directed displacement can be regulated. Therefore, it is possible to achieve the same effect as that of the first embodiment. Note that this point is the same for the second restriction piece 61.

Furthermore, in the above-described embodiment, the secondary battery 1 is described as an example of the electrochemical cell, but the present invention is not limited to this case, and it may be, for example, a capacitor (for example, a lithium ion capacitor) or a primary battery. It doesn't matter.
Furthermore, although the case where the first laminating member 30 and the second laminating member 40 are separated has been described as an example, the present invention is not limited to this case. For example, one laminated film may be bent to form the first laminated member 30 and the second laminated member 40. Furthermore, it is not necessary that the entire outer casing 3 is formed of a laminated film, and at least a part of the outer casing 3 may be formed of a laminated film.

  Furthermore, in the above-described embodiment, the secondary battery 1 having a circular shape in plan view has been described as an example, but the shape of the secondary battery 1 may be appropriately changed. For example, as shown in FIG. 15, an oblong secondary battery 1 in which a straight line portion and a semicircular portion are combined in a plan view may be used. In this case, as shown in FIG. 16, the shape of the electrode body 2 may be formed in an oval shape in plan view corresponding to the outer shape of the secondary battery 1.

Z ... Stacking direction 1 ... Secondary battery (electrochemical cell)
2 ... Electrode body 3 ... Exterior body 10 ... Positive electrode (electrode)
20 ... Negative electrode (electrode)
31, 41 ... Metal layer 32, 42 ... Inner resin layer (resin layer)
33, 43 ... Outer resin layer (resin layer)
37a ... 1st through-hole (through-hole)
37b ... second through hole (through hole)
50 ... First electrode plate (electrode plate)
51 ... Second electrode plate (electrode plate)
52 ... First electrode terminal plate (electrode terminal plate)
53 ... Second electrode terminal plate (electrode terminal plate)
54 ... 1st sealant film (sealant film)
55 ... Second sealant film (sealant film)
60 ... First regulation piece (regulation piece)
61 ... 2nd regulation piece (regulation piece)

(1) The electrochemical cell according to the present invention is formed of an electrode body having a plurality of electrodes laminated in the laminating direction, a laminate film having a metal layer and a resin layer covering both surfaces of the metal layer, An exterior body that houses an electrode body therein, an electrode plate that is integrally connected to the electrode body and that is disposed between the electrode body and the exterior body in the stacking direction, and the exterior body of the electrode plates. An electrode terminal plate fixed to the main surface facing the body side, and arranged between the electrode plate and the exterior body in a state of enclosing the electrode terminal plate, and welding the exterior body and the electrode plate to each other. A ring-shaped sealant film is provided, and a through-hole that exposes the electrode terminal plate to the outside is formed in the exterior body, and the inner diameter of the sealant film is formed smaller than the inner diameter of the through-hole. By that, before The electrode terminal plate has an inner peripheral edge portion arranged so as to project inside the through hole, the electrode terminal plate has the same outer diameter as the inner diameter of the sealant film, and the entire surface is the inner side of the sealant film and the through hole. Exposed to the outside through any one of the inner peripheral edge portion of the electrode terminal plate and the sealant film is formed so as to project with respect to the other member and to the other member. And a restriction piece that overlaps in the stacking direction and restricts the displacement of the electrode terminal plate toward the through hole side.

(4) The restriction piece is integrally formed with the electrode terminal plate so as to project from the outer peripheral edge portion of the electrode terminal plate toward the inner peripheral edge portion of the sealant film , and It may be sandwiched between the inner peripheral edge portion and the electrode plate in the stacking direction.

Claims (5)

An electrode body having a plurality of electrodes stacked in the stacking direction,
An exterior body formed of a laminate film having a metal layer and a resin layer covering both surfaces of the metal layer, and containing the electrode body inside,
An electrode plate that is integrally connected to the electrode body and that is disposed between the electrode body and the exterior body in the stacking direction,
An electrode terminal plate fixed to the main surface of the electrode plate facing the exterior body,
An annular sealant film disposed between the electrode plate and the outer package in a state of surrounding the electrode terminal plate, and welding the outer package and the electrode plate to each other,
The exterior body is formed with a through hole that exposes at least a part of the electrode terminal plate to the outside,
One of the electrode terminal plate and the sealant film is formed so as to project with respect to the other member and overlaps with the other member in the stacking direction, and the through hole side An electrochemical cell, characterized in that a regulating piece for regulating the displacement of the electrode terminal plate toward the side is provided. The electrochemical cell according to claim 1, wherein
An electrochemical cell in which a plurality of the restriction pieces are formed at intervals in the circumferential direction of the sealant film. The electrochemical cell according to claim 1, wherein
The said control piece is an electrochemical cell formed in the cyclic | annular form along the circumferential direction of the said sealant film. The electrochemical cell according to any one of claims 1 to 3,
The restriction piece is integrally formed with the electrode terminal plate so as to protrude from the outer peripheral edge portion of the electrode terminal plate toward the sealant film, and the lamination is provided between the sealant film and the electrode plate. An electrochemical cell sandwiched between directions. The electrochemical cell according to any one of claims 1 to 4,
The sealant film is formed so that its inner diameter is smaller than the inner diameter of the through hole,
The electrochemical cell in which the electrode terminal plate is formed thinner than the sealant film.

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