JP2012169222A - Power storage device and power storage apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated outer package-type power storage device capable of preventing the burst due to increase in internal pressure and controlling the ejection direction of gas and an electrolyte without causing cost increase while maintaining its external dimension and electrical performance.SOLUTION: A laminate 50 of sheet-like electrodes (10p,10n) and an electrolyte 51 are sealed in an outer package 100 in which the circumferences of two films (100a,100b) are bonded together in a frame-like adhesion region 60, and the adhesion region includes an internal pressure release part 70 and an internal pressure guide path 71 opening in the circumference of the outer package. A distance Wa from an inner periphery 61 to an outer periphery 62 in the frame-like adhesion region is longer than a distance Wc to a site 64 nearest to the inner periphery between the inner periphery and the internal pressure guide path, and the distance Wc is longer than a distance Wb to a site 63 nearest to the inner periphery between the inner periphery of the adhesion region and the internal pressure release part, and as the inner periphery of the adhesion region retreats to the side of the outer periphery at the time of internal pressure rising, the internal pressure release part communicates with the inner periphery and the internal pressure is released from an opening 72 of the internal pressure guide path.

Description

  The present invention relates to a power storage device in which a laminate formed by arranging a positive electrode and a negative electrode formed in a sheet shape to face each other via a separator is sealed in an outer package made of a laminate film or the like together with an electrolytic solution. Specifically, the present invention relates to a technique for releasing internal pressure when the internal pressure in the exterior body increases.

  As an electricity storage device having a laminate film or the like as an exterior body, there is a nonaqueous electrolyte electricity storage device such as a lithium ion capacitor (hereinafter referred to as a film exterior type electricity storage device). FIG. 1 is an external view of a film exterior type power storage device 1. A power storage element including an electrolytic solution is accommodated in the outer package 100. In addition, an electrode plate (tab) 40 that is connected to the positive electrode and negative electrode terminal of the power storage element and is connected to an external device is exposed to the outside of the outer package 100.

  The exterior body 100 is obtained by bonding the edges of four sides of two substantially rectangular laminate films. As is well known, the laminate film has a metal thin film made of aluminum or the like as a base material, a protective layer made of a resin such as polyester or nylon is provided on the outer side of the electricity storage device 1, that is, the front surface of the outer package 100, and the outer package. A heat-sealing layer made of a heat-fusible resin is provided on the back side of 100, that is, the inner surface of the film-clad electricity storage device 1.

  FIG. 2 is a diagram showing a structure inside the outer package 100 in the film-clad electricity storage device 1, and FIG. 2A is a perspective plan view of the film-clad electricity storage device 1. FIG. 2B is a side cross-sectional view corresponding to a cross section taken along the line aa in FIG. (C) is the figure which expanded the inside of the circle 200 in (B). The positive and negative electrodes (10p, 10n) in the film-covered electricity storage device 1 are obtained by applying the active material of each electrode in a substantially rectangular shape on the surface of a sheet-like conductor (11p, 11n) serving as a current collector. is there.

  The sheet-like conductors (11p, 11n) have a planar shape in which an electrode terminal 12 serving as a power outlet is provided on one side of a substantially rectangular shape. And the positive electrode and the negative electrode are arrange | positioned facing each other via the separator 30, and the laminated body 50 is comprised. The laminated body 50 is housed in an outer package 100 together with the electrolytic solution. The tab 40 is welded to the electrode terminal 12 formed on the sheet-like conductor (11p, 11n) by a method such as ultrasonic welding.

  In the example shown in FIG. 2, for ease of explanation, the stacked body 50 is shown as a single layer structure in which a pair of positive electrode 10p and negative electrode 10n are arranged to face each other with a separator 30 interposed therebetween. As is well known, as shown in FIG. 3A, the laminated film type film-clad electricity storage device 1 often has a multilayer structure. The laminated body 50 shown in FIG. 3 has the positive electrode 10p or the negative electrode 10n formed on the front and back, except for the outermost sheet-like electrode body 11. Moreover, in the film-clad type electricity storage device 1 in which the multilayer structure 50 is housed in the outer package 100, as shown in FIG. The electrode terminals 12 of the negative electrode 10n and the electrode terminals 12 of the negative electrode 10n are collectively welded to the tab 40, and the tab 40 is exposed to the outside of the exterior body 100.

  As shown in FIGS. 4A to 4C, the assembly procedure of the film-clad electricity storage device 1 having the above structure is as follows. First, the edges (101 to 100b) of two substantially rectangular laminate films (100a and 100b) are used. 104) are aligned and face each other, and the laminate 50 is disposed between the two laminated films (100a, 100b) with the tab 40 exposed to the outside (A). Next, the three edges 102 of the two laminate films (100a, 100b) are heat-sealed by pressing the edges (102 to 104) other than the predetermined edge 101 with a heated metal block. Let As a result, the three edges (102 to 104) of the two laminate films (100a, 100b) are bonded to each other, and the laminate films (100a, 100b) have a bag shape having an opening 105 on one edge 101 side. (B). In the drawing, a region (adhesion region) where two laminate films are bonded to seal the outer package 100 is indicated by hatching. Then, the electrolyte solution 51 is injected from the opening 105, and the edges 101 forming the opening 105 are thermally fused to each other, so that all the edges (101 to 104) of the two laminate films (100a, 100b) are bonded to each other. Are bonded to form the exterior body 100, and the laminated body 50 is sealed in the exterior body 100 (C).

  By the way, in all the electricity storage devices including the above-described film-covered electricity storage device 1 and dry batteries, gas may be generated from the electricity storage element due to misuse or deterioration with time. The generation of gas increases the internal pressure in a sealed container such as the outer package 100. As is well known, in an electricity storage device using a metal can such as a dry battery, as an internal pressure release function that releases gas to the outside of the battery when the internal pressure of the battery rises, the battery can is sealed, for example, a gasket or a terminal plate. This is realized by a safety valve that breaks in advance at the portion corresponding to the lid. However, it is structurally difficult to provide an internal pressure releasing function in the above-described film exterior type electricity storage device 1. When the internal pressure is excessively increased in the film-clad electricity storage device, the film expands, and the two laminated films bonded in the frame-shaped adhesive region are gradually peeled off from the inside of the frame. Eventually, the film ruptures and gas or electrolyte is ejected from that location. In addition, since it is not possible to specify where the rupture occurs, depending on the ruptured portion, there may be an adverse effect on surrounding devices and members. In addition, with respect to such a problem, each of the following Patent Documents 1 to 3 discloses a technique for controlling leakage or rupture in a film exterior type power storage device.

  Specifically, in Patent Document 1 below, the exterior body is not a simple rectangular laminate film, but a shape in which a part of one side protrudes in a trapezoidal shape, and an adhesive region is provided along the edge of the trapezoidal shape. In addition, a band-shaped adhesive region is provided so as to bisect the trapezoid by connecting the upper and lower bases of the trapezoid. And the hole which penetrates the front and back of an exterior body is drilled in the strip | belt-shaped adhesion | attachment area | region. As a result, when the trapezoidal non-adhesive part divided by the belt-like adhesive region is filled with gas, the belt-like adhesive region gradually peels off and becomes narrower, eventually reaching a through-hole, from which gas is passed. Is exhausted.

  In the technique described in Patent Document 2, a protruding fusion part that protrudes inwardly from the power storage element side, that is, the outer periphery of the exterior body, is formed in a part of the adhesion region, and the protruding fusion of one laminated film to be bonded is performed. The heat-fusible layer of the joint is cross-linked in advance. As a result, the internal pressure concentrates on the protruding fusion part due to its shape, so that the internal pressure can be released at a desired position. Furthermore, the internal pressure can be released at a predetermined pressure according to the degree of crosslinking.

  In the technique described in Patent Document 3, a frame body that surrounds an electricity storage element is housed in an exterior body, and a hole that communicates the inside and outside of the frame is provided in the frame body. Further, an exhaust pipe containing a film body that can be broken at a predetermined pressure is inserted into the hole, and the exhaust pipe is led out of the exterior body.

JP 2005-203262 A JP 2006-54099 A JP 2006-179442 A

  By the way, a film-clad electricity storage device is often used in a state of being housed in a certain housing. Further, rather than being used alone, a plurality of film-clad electricity storage devices are stacked in the thickness direction and used as an assembled battery connected in series or in parallel. Of course, the assembled battery is often used while being housed in a housing. Therefore, in the film exterior type electricity storage device described in Patent Documents 1 and 2 above, it may be possible to control the release position of the internal pressure by itself, but in the state of being housed in the housing, with the release of the internal pressure, Electrolyte will leak into the housing. In addition, the internal pressure release position of the single film exterior power storage device may not necessarily match the position where the internal pressure is desired to be released depending on the surrounding conditions of the device. For example, depending on the position of the electrode terminal in the laminate, the configuration related to the internal pressure release function (hole or protruding fusion part) cannot be formed at any other position than the specific position of the film-clad electricity storage device, the film-clad electricity storage device Depending on the installation location and installation orientation when it is actually used, if gas or electrolyte is discharged from a position related to the internal pressure release function, it may contaminate surrounding equipment and components. is there.

  Moreover, in the film exterior type electrical storage device of patent document 1 and 2, while the shape of an adhesion | attachment area | region is complicated, it is necessary to drill a hole in an exterior body or bridge | crosslink a part of heat-fusion layer. Therefore, the manufacturing cost increases. Furthermore, the area of an exterior body becomes large by the shape of the complicated adhesion | attachment area | region. That is, there is also a problem that the outer dimension of the film-clad electricity storage device itself is increased.

  In the film-clad electricity storage device described in Patent Document 3, it is possible to guide the opening end of the exhaust pipe to a desired position or outside the housing. However, manufacturing a special exhaust pipe with a built-in film body itself is not possible. It can be easily imagined that it is difficult. That is, the special exhaust pipe itself is expensive. Furthermore, since the frame is housed in the exterior body, the number of parts increases and the manufacturing process becomes complicated, resulting in further cost increase. Of course, since the frame is housed in the exterior body, it is difficult to reduce the size. In addition, in the film-type electricity storage device, compressing by applying a strong pressure in the thickness direction, reducing the outer dimension in the thickness direction, and reducing the contact resistance between the sheet-like electrode and the electrode body, It is necessary to improve the discharge performance or increase the electric capacity by shortening the distance between the positive and negative electrodes as much as possible. However, if there is a frame, not only the thickness that can be compressed is limited and it is difficult to reduce the thickness, but it is also difficult to improve electrical performance. If there is a hard frame in the exterior body, the frame body may be damaged during compression or the exterior body may be torn.

  Therefore, the present invention relates to an electrical storage device in which a laminate and an electrolytic solution in which a positive electrode and a negative electrode formed in a sheet shape are arranged to face each other with a separator sealed in an outer package of a laminate film. The purpose is to ensure that the internal pressure can be released when the internal pressure rises without causing an increase in cost while maintaining the required performance, and to guide the gas or electrolyte discharged along with the internal pressure release to the desired location. Yes. Another object of the present invention is to provide a power storage device in which the power storage device is housed in a housing.

In order to achieve the above object, in the present invention, a laminated body in which a positive electrode and a negative electrode formed in a substantially rectangular sheet shape are arranged to face each other with a separator interposed therebetween and an electrolytic solution are sealed in a film-shaped outer package. And an electricity storage device in which an electrode plate connected to an electrode terminal formed in the laminate is exposed outside the exterior body,
The exterior body is bonded to each other in an adhesive region that borders the periphery of two film materials having the same planar shape in a frame shape,
The laminate is disposed inside the frame-shaped adhesive region,
The frame-shaped adhesive region includes a non-adhesive region in which the two film materials are not in an adhesive state,
The non-adhesive region includes an internal pressure induction conduit that passes through the adhesive region along the circumferential shape of the frame and has an end that opens at the periphery of the exterior body, and a path from the start end of the internal pressure induction conduit to the end. And at least one or more internal pressure release portions,
A distance Wa between an inner periphery and an outer periphery of the frame-shaped adhesive region, a distance Wb from an inner periphery of the adhesive region to a portion closest to the inner periphery in the internal pressure release portion, and an inner periphery of the adhesive region The distance Wc to the portion closest to the inner circumference in the internal pressure induction conduit satisfies the relationship of Wb <Wc <Wa,
The internal pressure release portion is a process in which the frame-shaped adhesive region peels from the inner peripheral side toward the outer peripheral side and the inner periphery recedes when the internal pressure in the exterior body increases. The electric storage device communicates with the inner circumference that is retreating in advance of another region, and releases the internal pressure from the opening via the internal pressure induction conduit.

  Moreover, it can also be set as the electrical storage device by which the discharge pipe for guide | inducing the gas and electrolyte solution in an exterior body to the distance is attached to the terminal of the said internal pressure induction | guidance | derivation pipe line.

  The present invention also extends to a power storage device in which one or more power storage devices including the discharge pipe are housed in a housing, and the power storage device includes an external connection terminal connected to the electrode plate of the power storage device. A discharge port that is exposed to the outside of the housing, communicates the inside and outside of the housing, and a conduit that has a start end connected to the discharge pipe and a terminal end that is guided to the outside through the discharge port. And.

  According to the electricity storage device of the present invention, in a structure in which a laminated body in which a positive electrode and a negative electrode formed in a sheet shape are arranged to face each other via a separator and an electrolyte solution are sealed in an outer package body of a laminate film, The internal pressure can be reliably released when the internal pressure rises without incurring an increase in cost while maintaining a typical performance. Further, the internal pressure can be guided to a desired place. As a result, surrounding equipment and the like are not contaminated by exhausted gas or leaked electrolyte.

It is an external view of the conventional film exterior type electrical storage device. It is a figure which shows the structure in the exterior body of the conventional film exterior type electrical storage device. It is a figure which shows the general structure of the laminated body accommodated in the said exterior body. It is a figure which shows the assembly procedure of the conventional film exterior type electrical storage device. It is a figure which shows the structure of the film exterior type electrical storage device which concerns on the 1st Example of this invention. It is an external view of the film-clad electricity storage device according to the first embodiment. It is operation | movement explanatory drawing of the internal pressure open | release function in the film exterior type electrical storage device which concerns on the said 1st Example. It is a figure which shows an example of the assembly procedure of the film exterior type electrical storage device which concerns on the said 1st Example. It is an external view of the film exterior type electrical storage device concerning the 2nd example of the present invention. It is a figure which shows an example of the assembly procedure of the film exterior type electrical storage device which concerns on the said 2nd Example. It is an external view of the electrical storage apparatus which concerns on the 3rd Example of this invention. It is a figure which shows the structure of the assembled battery accommodated in the inside of the housing | casing of the said electrical storage apparatus. It is a figure which shows the structure of the said electrical storage apparatus. It is a figure which shows the modification of the internal pressure open | release part in the film-clad electricity storage device of each said Example. It is a figure which shows the other modification of the internal pressure release part in the film-clad type electrical storage device of each said Example. It is an external view of the film exterior type electrical storage device which concerns on the other Example of this invention.

=== First Embodiment ===
As a first embodiment of the present invention, a film-covered electricity storage device as a single unit is given. The film-clad electricity storage device (hereinafter, electricity storage device) according to the first embodiment has a structure in which the laminate 50 shown in FIGS. 2 and 3 is housed together with the electrolyte in the exterior of the laminate film. However, the electricity storage device according to the first embodiment is characterized by the planar shape of the adhesion region, and can release the pressure from a predetermined position when the internal pressure rises to a predetermined pressure in the electricity storage device. At the same time, the gas or electrolyte that leaks as the pressure is released can be released from any position of the electricity storage device.

  FIG. 5 is a perspective plan view of the electricity storage device 1a according to the first embodiment, and the adhesion region 60 in the exterior body 100 is indicated by hatching. Similar to the conventional power storage device 1, a frame-shaped adhesive region 60 is formed at the periphery of the rectangular laminated film outer package 100 so as to border the outer shape of the outer package 100. In this embodiment, the width Wa between the inner periphery 61 of the frame and the outer periphery of the exterior body 100 serving as the outer periphery 62 of the frame is substantially constant at any position of the rotating frame. The inner periphery 61 of the frame is in contact with the stacked body 50 in the exterior body 100, and the tab 40 connected to the electrode terminal 12 of the stacked body 50 is exposed outside the exterior body 100. In the following, the stacking direction of the sheet-like power storage elements in the stacked body 50, that is, the normal direction on the paper surface of FIG.

  In the power storage device 1a shown here, a substantially rectangular internal pressure release portion 70 is provided in the approximate center of the lower side of the rectangular frame-shaped adhesive region 60. The internal pressure releasing portion 70 is a portion where the two laminated films constituting the exterior body 100 are not heat-sealed. The internal pressure release portion 70 is similarly connected to a tubular region (internal pressure induction conduit) 71 that is not thermally fused. The internal pressure guide pipe 71 has an internal pressure release portion 70 as a start end and passes through an adhesive region 60 with an opening 72 provided at an appropriate position as an end. In this example, the adhesive region 60 is extended in the clockwise direction from the internal pressure release portion 70 provided below, bent once, and vertically penetrated to the opening 72 provided in the upper corner portion of the adhesive region 60. ing.

  Further, as to the formation position and dimensions of the internal pressure release portion 70 and the internal pressure induction conduit 71, as shown in FIG. 5, the inner circumference 61 in the adhesion region 60 and the inner circumference 61 in the rectangular internal pressure release portion 70 are arranged. The width between the upper edge 63 that is the closest part is Wb, and the inner edge 61 side edge that is the closest part to the inner circumference 61 in the inner circumference 61 and the inner pressure guide pipe 71 in the adhesion region 60 Wb <Wc <Wa, where Wc <Wc <Wa. The edge 63 on the inner periphery 61 side of the internal pressure release portion 70 is closer to the inner periphery 61 than any other position in the bonding region 60. The distance is short. FIG. 6 shows an external view of the electricity storage device 1a in the first embodiment. This figure shows a perspective view of the electricity storage device 1a when viewed from the upper side where the opening 72 of the internal pressure induction conduit 71 is formed. Further, in the illustrated example, the opening 72 which is the terminal end of the internal pressure induction conduit 71 is shown in an enlarged manner for easy understanding.

  7A to 7C are operation explanatory diagrams of the internal pressure release function in the electricity storage device 1a of the first embodiment. FIG. 7 shows a perspective plan view of the electricity storage device 1a when viewed from the front-rear direction. Moreover, the laminated body 50 is abbreviate | omitted in the figure. First, in a state where the internal pressure is normal, the inner periphery (61, 61a) of the frame-shaped adhesion region 60 maintains the original rectangular shape (A). As the internal pressure increases, the outer package 100 swells in the thickness direction, and when the internal pressure further increases, the frame-shaped adhesive region 60 of the two laminated films in the bonded state is restored to the initial inner periphery (dotted line in the figure). (Rectangle) 61a starts to peel toward the outer periphery 62. The internal pressure applied to the bonding region 60 is applied almost uniformly from the center in the frame, and if there is no significant difference in the bonding strength of each part of the bonding region 60, the inner periphery 61b of the frame that is actually bonded is the outer periphery 62. Retreating toward the side, the width of the bonding region 60 gradually narrows uniformly (B). When the peeling reaches the internal pressure release portion 70, the inside and outside of the exterior body 100 communicate with each other via the internal pressure induction conduit 71, and the gas or electrolyte discharged along with the increase in internal pressure passes through this conduit 71. Through the opening 72, it is opened to the atmosphere.

  Thus, in the electrical storage device 1a of the first embodiment, the internal pressure release portion 70 can be provided at an appropriate position according to the shape of the internal laminate 50 and the like. Furthermore, the position of the opening 72 where the internal pressure is actually opened can be arbitrarily set in consideration of the installation location and installation posture of the power storage device 1a. Then, the internal pressure 61 can be controlled by appropriately setting the distance Wb between the inner periphery 61 of the bonding region 60 and the inner pressure release portion 70 to the portion closest to the inner periphery 61.

  If the distance Wb from the inner periphery 61 of the frame-shaped adhesion region 60 is shorter than any other position of the adhesion region 60, the position of the internal pressure release portion 70 is, for example, the corner of the frame or two tabs. You may provide between 40. The internal pressure release line 71 may be formed so as to cross the tab. The distances (Wb, Wc) from the initial inner circumference 61 of the adhesion region 60 to the inner pressure release portion 70 and the closest edges (63, 64) in the internal pressure induction conduit 71 are the above formulas Wb <Wc <Wa. If satisfied, the width Wa of the adhesion region 60 may not be uniform. The shape of the internal pressure release portion 70 is not limited to a rectangle. Of course, the frame shape of the adhesion region 60 is not limited to a rectangle. The outer periphery 62 of the bonding region 60 may be inside the periphery of the exterior body 100. In any case, in the internal pressure release part 70, the position closest to the inner circumference 61 of the bonding region 60 and the distance wb to the inner circumference 61 need only satisfy the above inequality.

  As for the method of forming the internal pressure release portion 70, for example, when two laminated films are heat-sealed, it is not necessary to heat-fuse the portions that become the internal pressure release portion 70 and the internal pressure induction conduit 71. FIG. 8 shows an example of a method for forming the internal pressure release portion 70 and the internal pressure induction conduit 71. FIG. 8A shows an inner pressure release portion 70 in two laminated films (100a, 100b) and an edge 102 where a part of the inner pressure induction conduit 71 starting from the inner pressure release portion 70 is formed. It is a perspective view which shows the process to wear. By pressing the heated block 80 against the laminate film to be heat-sealed, the two laminated films in a laminated state are bonded to each other by heat-sealing. Here, the laminated film (100a, 100b) side is set as the rear, and the heating block 80 is pressed from the front. FIG. 8B is a perspective view showing the shape of the rear face 81 of the heating block 80 shown in FIG. 8A, that is, the end face (pressing end face) 81 on the side pressing the laminate film (100a, 100b). In the drawing, the portion of the pressing end surface 81 that is in contact with the laminate film (100a, 100b) at the time of heat-sealing is indicated by hatching.

  8C is connected to the internal pressure induction conduit 71 formed by the heating block 80 shown in FIGS. 8A and 8B, and an internal pressure induction conduit 71 that guides to the opening 72 is formed. FIG. 8D is a perspective view showing the shape of the pressing end face 91 of the heating block 90 shown in FIG. 8C. FIG. 8E is a diagram showing the arrangement relationship of the pressing end surfaces (81, 91) of the two heating blocks (80, 90) shown in FIGS. 8B and 8D, respectively. On the pressing end face (81, 91) of each heating block (80, 90), there are formed recesses (82, 92) that coincide with the planar shape of the internal pressure release part 70 and the internal pressure induction conduit 71 continuous thereto.

  Then, if the two laminated films (100a, 100b) are heat-sealed with these heating blocks (80, 90), the concave portions (82, 92) of these blocks (80, 90) The heating block (80, 90) does not come into contact with the laminate films (100a, 100b), and the heat-welded layer is not heat-sealed. That is, the edges (102, 103) of the two laminate films (100a, 100b) are bonded, leaving the internal pressure release part 70 and the internal pressure induction conduit 71. In addition, without using a plurality of heating blocks (80, 90), using a substantially L-shaped heating block integrally provided with the shape of the pressing end surface (81, 91) shown in FIG. You may form simultaneously from the opening part 70 to the opening 72 of the internal pressure induction | guidance | derivation pipeline 71. FIG.

  Further, the shape from the internal pressure release portion 70 to the opening 72 of the internal pressure induction conduit 71 is not limited to a substantially L shape, and may be a substantially U shape that bends twice, or may be bent without being bent once. The internal pressure induction conduit 71 may be formed linearly along the edge of the body 100. The method for forming the internal pressure release portion 70 and the internal pressure induction conduit 71 is not limited to the method shown in FIG. For example, the heat-sealing layer may not be provided in a portion that becomes the internal pressure release portion 70 or the internal pressure induction conduit 71 by patterning. A resin having a high melting point that is not heat-sealed may be applied to a portion that becomes the internal pressure release portion 70 or the internal pressure induction conduit 71. It is also conceivable that the laminated films (100a, 100b) are not bonded by heat fusion but bonded using an adhesive. In this case, an adhesive may be applied to the adhesion region 60 other than the internal pressure release portion 70 and the internal pressure induction conduit 71.

=== Second Embodiment ===
As described above, in the electricity storage device 1a of the first embodiment, the position of the internal pressure release portion 70 can be set as appropriate, and the internal pressure released by the internal pressure release portion can be released to the atmosphere at an appropriate location. it can. That is, the path of the internal pressure release part 70 and the internal pressure induction conduit 71 and the position of the opening 72 that opens the internal pressure to the atmosphere are flexibly set according to the shape of the laminated body 50, the installation location and installation orientation of the power storage device 1a. be able to. For example, when the internal pressure release portion 70 is provided below and the opening 72 of the internal pressure induction conduit 71 is provided above, and the vertical relationship of the electricity storage device 1a itself is matched with the vertical direction, the internal pressure release function is activated. Even when the electrolytic solution 51 enters the internal pressure induction conduit 71, if the gas is released to the atmosphere, the electrolytic solution stops below the internal pressure induction conduit 71 due to gravity. There is little possibility of leakage. Even if the position of the opening 72 and the vertical direction are not defined, if the opening 72 has a space for a member (porous member, fibrous member, etc.) for absorbing the electrolyte, the absorbing member is opened. If it arrange | positions in contact with 72, the leaked electrolyte solution will be absorbed by the absorption member, and a surrounding apparatus and member will not be contaminated with the leaked electrolyte solution.

  However, no matter how the position of the internal pressure release part 70 or the path of the internal pressure induction conduit 71 is devised, the opening 72 of the internal pressure induction conduit 71 cannot be directed upward, and there is no space for arranging the absorbing member. There is also a case where Some devices and parts do not want to be directly exposed to the gas released into the atmosphere even if the electrolyte does not leak. Therefore, in the electricity storage device according to the second embodiment of the present invention, the gas or the electrolyte can be discharged in a predetermined direction different from the direction of the opening 72 or can be guided to a position away from itself. It has become.

  FIG. 9 shows an external view of the electricity storage device 1b according to the second embodiment. As shown in the drawing, a pipe-like member (discharge pipe) 73 is attached to the opening 72 of the internal pressure induction conduit 71. In this example, the discharge pipe 73 is bent in an L shape, and the discharge pipe 73 is discharged from the exterior body 100 via the internal pressure induction conduit 71 by directing the opening end 74 in an arbitrary direction. The gas and electrolyte solution to be used can be guided in a predetermined direction. Further, if the gas or the electrolyte is led to a place away from the electricity storage device 1b, the discharge pipe 73 itself may be lengthened, or a tube guided from another place to the opening end 74 of the discharge pipe 73, etc. May be connected.

  The discharge pipe 73 may be inserted into the opening 72 of the internal pressure induction pipe 71 after assembling the power storage device 1a of the first embodiment, or at the same time as the opening 72 of the internal pressure induction pipe 71 is formed. It may be attached. FIG. 10 shows a method of attaching the discharge pipe 73 simultaneously with the formation of the opening 72 of the internal pressure induction conduit 71. FIG. 10A is a perspective view showing the method, and an outline of the process of thermally fusing the edge 103 where the opening 72 of the internal pressure induction conduit 71 is formed in the two laminate films (100a, 100b). Is shown. FIG. 10B is a diagram showing the shape of the pressing end surface 91b of the heating block 90b used in the heat fusion process. And (C) is a bb arrow sectional view in (A). On the pressing end surface 91 b of the heating block 90 b, the opening 72 side of the internal pressure induction conduit 71 is formed in a shape that follows the outer shape of the discharge pipe 73. Specifically, a semi-cylindrical recess 93 obtained by cutting a cylinder in the diameter direction is provided at a position corresponding to the opening 72 of the internal pressure induction conduit 71, and the laminate film (100a, 100b) together with the heating block 90b. A similar semi-cylindrical recess 84 is also provided on the table 83 on which is mounted. If the heating block 90b is pressed in a state where the discharge pipe 73 is disposed between the two laminate films (100a, 100b), the discharge pipe 73 is fused with the heat-sealing layer of the laminate film (100a, 100b). Attached and fixed to the opening 72 of the internal pressure induction conduit 71. The material of the discharge pipe 73 is preferably a material that is not corroded by gas or electrolyte. For example, a polyamide-based resin (nylon) or a fluororesin can be considered.

=== Third embodiment ===
As a third embodiment of the present invention, a power storage device in which the power storage device 1b according to the second embodiment is housed in a casing will be described. The power storage device according to the third embodiment utilizes the structure (70, 71, 72, 74) related to the internal pressure release function in the power storage device 1b of the second embodiment, and when the internal pressure release function is activated, Gas and electrolyte discharged to the outside of the exterior body 100 can be guided out of the casing to prevent contamination inside the casing. Here, a power storage device is described in which a battery pack in which a plurality of power storage devices 1b are connected in series or in parallel is housed in a casing. In FIG. 11, the external appearance of the electrical storage apparatus 110 which concerns on a 3rd Example was shown with the perspective view when it sees from upper direction. An external connection terminal 112 is provided on the upper surface 114 of the rectangular parallelepiped casing 111 so as to be electrically connected to an external device to take out electric power from the internal assembled battery or to charge the assembled battery. Yes. Further, a hole (discharge port) 113 that communicates the inside and outside of the casing 111 is formed in the same upper surface 114. A conduit 75 for guiding the gas or electrolyte discharged when the internal pressure release function is activated in the power storage device 1b inside the casing 111 to the outside of the casing 111 is provided from the outlet 113 to the casing. 111 is exposed to the outside.

  FIG. 12 is a schematic diagram of the assembled battery 1 c housed in the housing 111 of the power storage device 110. FIG. 12A is a perspective view of the assembled battery 1c, and FIG. 12B is a plan view when the assembled battery 1c is viewed from above where the tab 40 is formed. Here, in order to simplify the drawing, an assembled battery 1c including four power storage devices 1b is shown. Each power storage device 1 b has an opening 72 that is a terminal end of the internal pressure induction conduit 71 at an upper corner of the exterior body 110, and a discharge pipe 73 is attached to the opening 72. Of course, the formation position of the opening 72 of the internal pressure guide pipe 71, that is, the attachment position of the discharge pipe 73 can be set as appropriate. As shown in FIG. 12, the assembled battery 1c has a structure in which the tabs 40 of the electricity storage devices 1b adjacent in the stacking direction are electrically connected to each other using welding or a terminal block. In the drawing, the positive and negative polarities of the tab 40 are indicated by the signs “+” and “−”, and in the illustrated assembled battery 1c, a plurality of power storage devices 1b are connected in series.

  FIG. 13 shows the internal structure of the power storage device 110. 11A is a cross-sectional view taken along the line cc in FIG. 11, and FIG. 11B is a cutaway perspective view when a part of the casing 111 of the power storage device 110 is cleaved. The plurality of power storage devices 1b constituting the assembled battery 1c are connected to each other with tabs 40 of the adjacent power storage devices 1b so as to be connected in series, and each of the positive electrode and the negative electrode of the assembled battery 1c formed in series connection. The tab 41 corresponding to is connected to the external electrode terminal 112 outside the casing 111 through a connection path that connects the inside and outside of the casing 111. As described above, the power storage device 110 includes a structure that discharges the gas and the electrolyte from the power storage device 1b to the housing 111 when the internal pressure release function is activated in the internal power storage device 1b.

  As previously shown in FIG. 11, the upper surface 114 of the casing 111 is provided with a discharge port 113 that communicates the inside and outside of the casing 111, and the opening of the internal pressure ventilation pipe 71 of each power storage device 1 b. 72 is connected to a discharge pipe 73. And each discharge pipe 73 has joined so that it may become one pipe line 75, as shown by hatching of the halftone dot in the figure. Then, the pipe line (merging pipe line) 75 extends to the back surface 115 side of the upper surface 114 of the housing 111, penetrates the hole 113 formed in the upper surface 114 of the housing 111, and is guided out of the housing 111. The opening 76 serving as the terminal end of the merge pipe 75 is exposed outside the casing 111. Thereby, when the internal pressure release function of a certain power storage device 1b is activated in the housing 111, the gas or electrolyte from the device 1b is connected to the opening 72 of the internal pressure induction conduit 71, and It is guided to the continuous merging pipeline 75 and guided to the outside of the casing 111. What is necessary is just to prevent the discharged | emitted gas and electrolyte solution from adhering to the housing | casing 111 by connecting a pipe line etc. to the opening 76 of the termination | terminus of the merge pipe line 75 further.

  Note that the discharge port 113 is not limited to the upper surface 114 of the housing 111, and can be opened on an appropriate side surface so as to guide the gas or the electrolyte in a desired direction. Alternatively, the same number of outlets 113 as the power storage devices 1 b may be provided without joining the pipes 74, and the pipes 74 from the power storage devices 1 b may be led to the individual outlets 113.

=== Other Embodiments ===
In each of the above-described embodiments, the width Wa between the inner periphery 61 of the frame and the outer periphery of the exterior body 100 serving as the outer periphery 62 of the frame is almost constant at any position of the rotating frame, but of course, it needs to be constant. There is no. The shortest distance Wc to the inner periphery 61 of the frame may be larger than the shortest distance Wb to the inner periphery 61 in the internal pressure release portion 70 at any position on the way of extension of the internal pressure guide pipe 71. That is, it is sufficient if Wa>Wc> Wb.

  In each of the embodiments described above, the internal pressure release portion 70 has a rectangular shape wider than the internal pressure induction conduit 71, but is not limited thereto. FIG. 14 shows a modification of the internal pressure release portion. Like the power storage device 1d shown in FIG. 14A, for example, a triangular internal pressure release portion 70d may be used. In the electricity storage device 1e shown in FIG. 14B, the internal pressure release portion 70e is formed by bending the internal pressure induction conduit 71 to the inner peripheral side.

  Further, the internal pressure release portion is not limited to one location, and there may be a plurality of locations on the way of the internal pressure induction conduit 71. FIG. 15A illustrates a power storage device 1f having two internal pressure release portions 71f, and FIG. 15B illustrates a power storage device 1g having three internal pressure release portions 71g. Of course, there may be more than four. Moreover, each internal pressure release part does not need to be the same shape. In any case, the inner edge 61 side edge 63 of the inner pressure release part 70 only needs to be inside the inner edge side edge of the inner pressure induction conduit 71.

  In the first embodiment, a pipe-shaped member may be embedded in the opening 72 of the internal pressure induction conduit 71 in advance, and the discharge tube 73 and the conduit may be connected to the pipe as necessary. . As a method of embedding the pipe-shaped member, as in the method of attaching the discharge pipe 73 of the electricity storage device 1b of the second embodiment shown in FIG. 10, when laminating the laminate films (100a, 100b), The formation of the opening 72 of the internal pressure induction conduit 71 and the embedding of the pipe-shaped member may be performed simultaneously.

  In each of the above embodiments, in the structure of the electricity storage device (1a, 1b), the positive and negative electrode terminals 12 in the stacked body 50 protrude in the same direction, and the tab 40 is also exposed from the exterior body 100 in the same direction. Of course, not limited to such a structure, like the power storage device 1 h shown in FIG. 16, the electrode terminals 12 protrude alternately in opposite directions, and the positive and negative electrode tabs 40 extend in the opposite direction of the outer package 100. The structure which protrudes may be sufficient. In the illustrated example, the internal pressure release portion 70 is formed at an edge portion where the tab 40 does not protrude, and the internal pressure induction conduit 71 extends the same edge portion upward and reaches the opening 72 as it is.

  Note that the subject of the present invention is not limited to a chargeable / dischargeable power storage device, and the power storage element is housed in the exterior of the laminate film, and gas may be generated by an electrochemical reaction by the power storage element. It is an electricity storage device. Accordingly, the power storage device may be a primary battery.

1, 1a, 1b, 1d film exterior type electricity storage device, 1c assembled battery,
10p, 10n electrode, 11, 11p, 11n sheet current collector, 12 electrode terminal,
30 separator, 40, 41 tab, 50 laminate, 60 bonding area,
61 inner circumference of the adhesion area, 62 outer circumference of the adhesion area, 70 internal pressure release portion,
71 Internal pressure induction line, 72 Opening of internal pressure induction line, 73 Discharge pipe 75 Confluence line,
80, 90, 90b heating block, 100 exterior body,
100a, 100b laminate film, 110 power storage device, 111 housing,
112 External connection terminal, 113 Outlet

Claims (3)

A laminate formed by arranging a positive electrode and a negative electrode formed in a substantially rectangular sheet shape to face each other with a separator interposed therebetween and an electrolyte solution are sealed in a film-shaped exterior body, and an electrode formed in the laminate An electricity storage device in which an electrode plate connected to a terminal is exposed outside the outer package,
The exterior body is bonded to each other in an adhesive region that borders the periphery of two film materials having the same planar shape in a frame shape,
The laminate is disposed inside the frame-shaped adhesive region,
The frame-shaped adhesive region includes a non-adhesive region in which the two film materials are not in an adhesive state,
The non-adhesive region includes an internal pressure induction conduit that passes through the adhesive region along the circumferential shape of the frame and has an end that opens at the periphery of the exterior body, and a path from the start end of the internal pressure induction conduit to the end. And at least one or more internal pressure release portions,
A distance Wa between an inner periphery and an outer periphery of the frame-shaped adhesive region, a distance Wb from an inner periphery of the adhesive region to a portion closest to the inner periphery in the internal pressure release portion, and an inner periphery of the adhesive region The distance Wc to the portion closest to the inner circumference in the internal pressure induction conduit satisfies the relationship of Wb <Wc <Wa,
The internal pressure release portion is a process in which the frame-shaped adhesive region peels from the inner peripheral side toward the outer peripheral side and the inner periphery recedes when the internal pressure in the exterior body increases. In communication with the inner circumference that is retreating prior to the other area, the internal pressure is released from the opening via the internal pressure induction conduit,
An electricity storage device characterized by the above.   2. The electric storage device according to claim 1, wherein a discharge pipe for guiding a gas or an electrolytic solution in the exterior body to a distance is attached to a terminal end of the internal pressure induction conduit.   A power storage device in which one or more power storage devices according to claim 2 are housed in a housing, and an external connection terminal connected to the electrode plate of the power storage device is exposed to the outside of the housing, An electrical storage comprising: a discharge port that communicates the inside and outside of the housing; and a conduit that has a start end connected to the discharge pipe and a termination that is guided to the outside of the housing via the discharge port apparatus.

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