JP2011113929A - Power storage element having laminate film outer package - Google Patents

Abstract

The impact resistance of a power storage device having an exterior body made of a laminate film and having an electrode laminate is improved in a state where sealing and insulating properties are ensured.
A lead for negative electrode terminal 3 includes a first flat surface portion 31 in surface contact with a cup bottom surface 15a in the outer package 1, and an outer package body 1 bent from the first flat surface portion 31 and facing the cup bottom surface 15a. An intermediate portion 32 reaching the inner surface 16, and a second flat portion 33 that is bent from the intermediate portion 32 and contacts the inner surface 16 toward the heat seal portion 11. The end portions of the respective ear portions 23 extending from the negative electrode plate 21 are combined with the inner surface of the first flat portion 31 (the surface opposite to the surface contacting the cup bottom surface 15a) and a part of the intermediate portion 32 continuous therewith. Fix by sonic welding. The lead for the positive terminal is configured similarly to the lead 3 for the negative terminal.
[Selection] Figure 2

Description

  The present invention relates to a power storage device having a laminate film outer package (an outer package made of a laminate film).

In recent years, attention has been focused on midnight power storage systems, distributed energy storage systems based on natural energy generation technologies such as solar and wind power, and energy storage systems for electric vehicles, from the viewpoint of the conservation of the global environment and effective use of energy for resource conservation. Collecting.
As the power storage elements for these power storage systems, nonaqueous electrolyte power storage elements such as lithium ion batteries, electric double layer capacitors, and lithium ion capacitors are preferred. These non-aqueous electrolyte storage elements are made by combining a positive electrode plate and a negative electrode plate in which an active material layer is formed on a current collector made of a metal foil, and an electrode body made of a separator disposed between them into a metal can or a laminate. It is manufactured by sealing it after putting it in an exterior body made of a film and injecting an electrolytic solution.

An exterior body made of a laminate film is formed by heat-sealing a laminate film having a metal intermediate layer and a heat-meltable resin layer with the heat-meltable resin layer as the innermost layer. As the exterior body made of a laminate film, there are a pouch mold in which a heat seal portion is formed at the center in the thickness direction and a cup mold having a cup-shaped portion on one surface in the thickness direction.
In a nonaqueous electrolyte storage element using an exterior body made of a metal can, in order to obtain a high capacity and high output by increasing the facing area of the electrodes, a long positive electrode plate and a negative electrode plate are long as the electrode body. An electrode winding body wound through a separator is used. In the case of using an electrode winding body, the innermost part or the outermost part of the positive electrode plate and the negative electrode plate is provided with one portion where there is no active material layer and the current collector is exposed. One end of the lead for the lead and the lead for the negative electrode terminal is fixed.

  In a thin non-aqueous electrolyte storage element using an exterior body made of a laminate film, in addition to the above-described electrode winding body, a plurality of positive and negative electrode plates formed in a substantially rectangular shape are interposed between the electrode bodies. An electrode laminate in which separators are arranged and laminated is also used. In the case of using an electrode laminate, each of the positive electrode plate and the negative electrode plate is provided with an ear portion that has no active material layer and the current collector is exposed, and the end portion of each ear portion of the positive electrode plate is bundled to be a positive electrode terminal The ends of the ears of the negative electrode plate are gathered together with one end of the lead for the negative electrode and fixed to one end of the lead for the negative electrode terminal. And the lead for positive electrode terminals and the lead for negative electrode terminals are pulled out to the exterior of the exterior body via the heat seal part.

  An electrical storage element using an exterior body made of a laminate film has a lower structural strength than an electrical storage element using an exterior body made of a metal can. For this reason, when subjected to an impact such as dropping or vibration, the positive / negative electrode terminal lead may be damaged near the heat seal part, or the connection part between the positive / negative electrode terminal lead and the electrode body may be damaged. There is. Various proposals have been made in order to solve the problems of the electricity storage element using such an outer package made of a laminate film.

In Patent Document 1, in order to improve the bonding force between the electrode tab (ear part) of the electrode laminate and the electrode lead (positive electrode / negative electrode terminal lead), the electrode lead is composed of two lead members, It is described that one end is in close contact with the other and the other end is open, and the upper and lower surfaces of the electrode tab laminate (the portion where the ends of a plurality of ears are overlapped) are simultaneously covered and bonded at the other end. Yes.
In Patent Document 2, in order to prevent the external lead (positive electrode / negative electrode terminal lead) from breaking near the interface of the heat seal portion in the exterior body, the external lead is made of an electrode winding body or an electrode laminate. It is described that the electrode is bent at a portion located between the electrode group (electrode body) and the heat seal portion.

  In Patent Document 3, in a laminated battery (battery equipped with an electrode laminate), in order to suppress vibration input to the electrode lead (ear part) from the outside via an electrode tab (positive electrode / negative electrode terminal lead). In addition, it is described that a convex portion protruding toward at least one of the electrode stacks in the stacking direction is provided as a vibration absorbing portion on the heat seal portion side from the portion where the electrode lead of the electrode tab in the outer package is fixed. ing.

JP 2008-27892 A JP 2001-266842 A JP 2004-39274 A

Among the storage elements having a laminate film outer package, those having an electrode laminate as an electrode body composed of a positive electrode plate, a negative electrode plate, and a separator are, as described above, a positive electrode / negative electrode terminal lead, a positive electrode plate, a negative electrode plate, Since there is an ear portion made of a thin metal foil, the strength against an impact such as dropping or vibration is weaker than that provided with an electrode winding body.
The method of Patent Document 1 merely reinforces the end of the ear portion on the positive electrode / negative electrode terminal lead side, and is formed of a thin metal foil between the positive electrode / negative electrode terminal lead and the positive electrode plate and the negative electrode plate. Ears still exist.
The method of Patent Document 2 may be effective for an electrode winding body, but the effect for an electrode stack is insufficient.

In the method of Patent Document 3, it is conceivable that by providing the vibration-absorbing convex portion, the power storage element becomes large, and the convex portion exists near the heat seal portion, so that the hermeticity of the heat seal portion is affected. . If excessive heat is applied to the laminate film by increasing the heating temperature in order to increase the hermeticity of the heat seal part, the insulation performance between the metal intermediate layer and the lead for the positive and negative electrode terminals that make up the laminate film will decrease. It is also possible to do.
An object of the present invention is to improve the impact resistance of a power storage device including an electrode stack, in which the outer package is made of a laminate film, while ensuring sealing and insulating properties.

  In order to solve the above-described problems, the electricity storage device having the cup-shaped laminate film outer package according to the present invention includes a laminate film having a metal intermediate layer and a heat-meltable resin layer, wherein the heat-meltable resin layer is the innermost layer. An exterior body that is formed by heat sealing and has a cup-shaped portion on one surface in the thickness direction, and a plurality of positive and negative electrode plates housed in the exterior body have a separator disposed therebetween. The electrode stacks stacked in layers, the electrolyte contained in the outer package, and one end of each ear extending from the plurality of positive plates are fixed together at one end, and the other end is fixed to the outer package A positive terminal lead drawn out through a heat seal portion and one end of each ear extending from the plurality of negative plates are fixed together at one end, and the other end is outside the exterior body Through the heat seal A negative electrode terminal lead that is drawn out, and the positive electrode terminal lead and the negative electrode terminal lead are each in a first plane portion in surface contact with a cup bottom surface in the outer package in the outer space of the outer package, An intermediate portion that bends from the first flat portion and reaches the inner surface of the exterior body facing the cup bottom surface, and a second flat portion that is bent from the intermediate portion and faces the heat seal portion while contacting the inner surface, The end portions of the respective ear portions are fixed together on a surface opposite to the surface of the first flat portion that contacts the bottom surface of the cup.

  An electricity storage device having a pouch-type laminate film outer package of the present invention is formed by laminating a laminate film having a metal intermediate layer and a heat-meltable resin layer with the heat-meltable resin layer as an innermost layer, An exterior body in which a heat seal portion is formed at the center in the vertical direction, and an electrode laminate in which a plurality of positive plates and negative plates housed in the exterior body are laminated with separators therebetween And the electrolyte contained in the exterior body, and one end of each of the ears extending from the plurality of positive plates are fixed together at one end, and the other end is connected to the outside of the exterior body via a heat seal part. The lead for the positive terminal pulled out and the end of each ear extending from the plurality of negative plates are fixed together at one end, and the other end is pulled out to the outside of the exterior body via a heat seal part. For negative terminal Each of the positive electrode terminal lead and the negative electrode terminal lead is in surface contact with one of two parallel or substantially parallel surfaces facing each other in the thickness direction in the outer package in the outer space of the outer package. A first flat portion, an intermediate portion that is bent from the first flat portion and reaches the central portion in the thickness direction of the exterior body, and a second flat portion that is bent from the intermediate portion and is directed to the heat seal portion, The end portions of the respective ear portions are fixed together on the opposite surface of the first plane portion that contacts one of the two surfaces.

In the electricity storage device having the pouch-type laminate film outer package, the first flat portion of the positive electrode terminal lead is in surface contact with one of the two surfaces, and the first flat portion of the negative electrode terminal lead is the two It is preferable that the other surface is in surface contact.
The negative electrode terminal lead of the electricity storage device having the laminate film outer package of the present invention has a thickness of any one of nickel, nickel alloy, copper, nickel-plated copper, and a clad material made of copper and nickel. Is preferably formed in a plate shape of 0.08 to 0.5 mm.

The positive electrode terminal lead of the electricity storage device having the laminate film outer package of the present invention is preferably formed of aluminum or an aluminum alloy into a plate shape having a thickness of 0.08 to 0.5 mm.
According to the electricity storage device having the cup-shaped laminate film outer package of the present invention, when an impact is applied due to dropping or vibration, the intermediate portion of the positive / negative electrode terminal lead absorbs the impact, and the first planar portion Since the frictional force acts between the cup and the cup bottom, the force accompanying the impact is difficult to be transmitted to the ear. Moreover, since the length from the edge part of the heat seal part of a 2nd plane part is taken long, since heat seal can be performed by the method which is not different from the past, sealing property and insulation are ensured.

  According to the electricity storage device having the pouch-type laminate film outer package of the present invention, when an impact is applied by dropping or vibration, the intermediate portion of the positive / negative electrode terminal lead absorbs the impact, and the first plane portion Since one of two parallel or almost parallel surfaces facing each other in the thickness direction of the exterior body is in surface contact with each other, a frictional force acts between them. It is hard to be transmitted to. Moreover, since the length from the edge part of the heat seal part of a 2nd plane part is taken long, since heat seal can be performed by the method which is not different from the past, sealing property and insulation are ensured.

The electricity storage device having the laminate film outer package of the present invention has high impact resistance and ensures sealing and insulating properties.
Therefore, the power storage device of the present invention is used in the field of hybrid drive systems combining an internal combustion engine or a fuel cell, a motor, and a power storage device, particularly in automobiles, OA equipment, countermeasures for instantaneous voltage drop, and further assists for instantaneous power peak. Can be suitably used.

It is a front view which shows 1st Embodiment of the electrical storage element which has the laminate film exterior body of this invention. It is a fragmentary sectional view which shows the electrical storage element which has the cup type laminated film exterior body of 1st Embodiment. It is a front view which shows 2nd Embodiment of the electrical storage element which has the laminate film exterior body of this invention. It is a fragmentary sectional view which shows the electrical storage element which has the pouch-type laminate film exterior body of 2nd Embodiment. It is a front view which shows 3rd Embodiment of the electrical storage element which has the laminate film exterior body of this invention. It is a fragmentary sectional view which shows the electrical storage element which has the pouch-type laminate film exterior body of 3rd Embodiment. It is a fragmentary sectional view which shows the prior art example of the electrical storage element which has a cup type laminated film exterior body. It is a fragmentary sectional view which shows the comparative example of the electrical storage element which has a cup type laminated film exterior body. It is a fragmentary sectional view which shows the comparative example of the electrical storage element which has a cup type laminated film exterior body. It is a fragmentary sectional view which shows the comparative example of the electrical storage element which has a cup type laminated film exterior body.

[First Embodiment]
FIG. 1 is a front view showing a first embodiment of a power storage device having a laminate film exterior body of the present invention.
This power storage element is a rectangular cup-type non-aqueous lithium-type power storage element, and includes an exterior body 1, an electrode laminate 2, an electrolytic solution, a negative terminal lead 3, and a positive terminal lead 4. ing. The electrode laminate 2 and the electrolytic solution are accommodated in the exterior body 1. The electrode laminate 2 is disposed in the rectangular cup portion 15.

  One end of the negative electrode terminal lead 3 is connected to the ear portion 23 of the negative electrode plate of the electrode laminate 2, and the other end is drawn out of the exterior body 1 through the heat seal portion 11. One end of the positive electrode terminal lead 4 is connected to the ear portion 24 of the positive electrode plate of the electrode laminate 2, and the other end is drawn out of the exterior body 1 through the heat seal portion 11. The exterior body 1 has a heat seal part 12 at an edge opposite to the heat seal part 11, and also has a heat seal part 13 at an edge perpendicular to both the heat seal parts 11 and 12.

  As shown in FIG. 2, the outer package 1 includes a laminate film 5 in which a polypropylene film (heat-meltable resin layer) 51, an aluminum foil (metal intermediate layer) 52, and a nylon film 53 are laminated. It is formed by heat sealing as the innermost layer. As shown in FIG. 2, the electrode laminate 2 is formed by laminating a plurality of negative plates 21 and positive plates 22 with a separator 25 interposed therebetween.

  As shown in FIG. 2, the negative electrode terminal lead 3 is bent from the first flat surface portion 31 and the first flat surface portion 31 in surface contact with the cup bottom surface 15 a in the external body 1 in the internal space of the external body. There is an intermediate portion 32 that reaches the inner surface 16 of the outer package 1 that faces the cup bottom surface 15 a, and a second flat portion 33 that is bent from the intermediate portion 32 and contacts the inner surface 16 toward the heat seal portion 11. Each of the ear portions 23 extending from the negative electrode plate 21 is formed on the inner surface of the first flat portion 31 and a part of the intermediate portion 32 continuous with the first flat portion 31 (the surface opposite to the surface where the first flat portion 31 contacts the cup bottom surface 15a). The ends are collectively fixed by ultrasonic welding, resistance welding, solder connection, silver solder connection, or the like.

Although not shown in FIG. 2, the positive electrode terminal lead 4, similarly to the negative electrode terminal lead 3, has a first flat surface portion, an intermediate portion, and a second flat surface portion in the exterior body internal space, and the positive electrode plate 22. The end portions of the respective ear portions 24 extending from the first flat portion and the inner surface of a part of the intermediate portion continuing to the first flat portion (the opposite surface of the surface where the first flat portion contacts the cup bottom surface 15a), It is fixed by ultrasonic welding, resistance welding, solder connection, silver solder connection, etc.
According to the electricity storage device of this embodiment, when an impact is applied due to dropping or vibration, the intermediate portion 32 of the negative electrode terminal lead 3 absorbs the impact, and the first flat portion 31 and the cup bottom surface 15a face each other. The contact force causes a frictional force between them, and the positive terminal lead 4 functions in the same manner. Therefore, the force accompanying the impact is not easily transmitted to the ear portions 23 and 24.

Moreover, the heat seal is made to be conventional by increasing the length (dimension b) starting from the boundary point (point on the line A) between the heat seal portion 11 of the second plane portion 33 and the inside of the exterior body 1. Since it can be performed by a method that does not change (normal temperature conditions), sealing and insulating properties are ensured.
If the dimension b is too short, the positive electrode / negative electrode terminal lead and the metal intermediate layer of the laminate film are likely to contact each other at the heat seal portion. If the dimension b (and the total length of the positive electrode / negative electrode terminal lead in the outer package: dimension a) is too long, only a small electrode laminate can be accommodated in the same cup, so that the volume energy density of the energy storage device becomes small. The dimension b is preferably 0.05 mm or more and 5.0 mm or less, and more preferably 0.1 mm or more and 3.0 mm or less. The dimension c of the first plane portion 31 is preferably 1.0 mm or greater and 3.0 mm or less.
Furthermore, since the force accompanying the impact is not easily transmitted to the ear portions 23 and 24, the backlash of the electrode laminate 2 inside the exterior body 1 can be reduced, so that the electrode active material is missing when the impact is applied by dropping or vibration. Can also be prevented.

[Second Embodiment]
FIG. 3 is a front view showing a second embodiment of the electricity storage device having the laminate film exterior body of the present invention.
This power storage element is a rectangular pouch-type non-aqueous lithium-type power storage element, and includes an exterior body 1, an electrode laminate 2, an electrolytic solution, a negative terminal lead 3, and a positive terminal lead 4. ing. The electrode laminate 2 and the electrolytic solution are accommodated in the exterior body 1.

The negative terminal lead 3 and the positive terminal lead 4 are arranged in the heat seal portions 11a and 11b on the opposite sides. In this example, an electrolytic solution is injected from the heat seal portion 14 at the edge perpendicular to the heat seal portions 11a and 11b.
One end of the negative electrode terminal lead 3 is connected to the ear 23 of the negative electrode plate of the electrode laminate 2, and the other end is drawn out of the exterior body 1 through the heat seal part 11 a. One end of the positive terminal lead 4 is connected to the ear portion 24 of the positive electrode plate of the electrode laminate 2, and the other end is drawn out of the exterior body 1 through the heat seal portion 11 b.

  As shown in FIG. 4, the outer package 1 includes a laminate film 5 in which a polypropylene film (heat-meltable resin layer) 51, an aluminum foil (metal intermediate layer) 52, and a nylon film 53 are laminated. It is formed by heat sealing as the innermost layer. As shown in FIG. 4, the electrode laminate 2 is obtained by laminating a plurality of negative plates 21 and positive plates 22 with a separator 25 interposed therebetween.

  As shown in FIG. 4, the negative electrode terminal lead 3 is in surface contact with one of the parallel or substantially parallel surfaces 17 and 18 facing in the thickness direction in the exterior body 1 in the interior space of the exterior body. A first flat portion 31, an intermediate portion 32 bent from the first flat portion 31 and reaching the central portion in the thickness direction of the exterior body 1, and a second bent toward the heat seal portion 11a from the intermediate portion 32 The plane portion 33 is provided. Respective ears extending from the negative electrode plate 21 to the inner surface of the first flat portion 31 and a part of the intermediate portion 32 continuing to the first flat portion 31 (the surface opposite to the surface where the first flat portion 31 contacts the surface 17 of the exterior body 1) The end portions of the portion 23 are collectively fixed by ultrasonic welding, resistance welding, solder connection, silver solder connection, or the like.

  Although not shown in FIG. 4, the positive electrode terminal lead 4, as well as the negative electrode terminal lead 3, are parallel or substantially parallel inner surfaces 17 and 18 that face each other in the thickness direction inside the outer package 1 in the outer space of the outer package. A first flat portion that is in surface contact with one inner surface 17, an intermediate portion that is bent from the first flat portion and reaches the center in the thickness direction of the exterior body 1, and is bent from the intermediate portion and is a heat seal portion It has the 2nd plane part which goes to 11b. Each of the ears 24 extending from the positive electrode plate 22 on the inner surface of the first flat portion and a part of the intermediate portion continuous thereto (the surface opposite to the surface where the first flat portion contacts the surface 17 of the exterior body 1). The ends are collectively fixed by ultrasonic welding, resistance welding, solder connection, silver solder connection, or the like.

According to the electricity storage device of this embodiment, when an impact is applied by dropping or vibration, the intermediate portion 32 of the negative electrode terminal lead 3 absorbs the impact, and the first flat portion 31 and the inside of the exterior body 1 Since the surface 17 and the surface contact each other, a frictional force acts between them, and the positive terminal lead 4 functions in the same manner, so that the force accompanying the impact is not easily transmitted to the ear portions 23 and 24.
Moreover, the heat seal is made to be conventional by increasing the length (dimension b) starting from the boundary point (point on the line A) between the heat seal portion 11a of the second plane portion 33 and the inside of the exterior body 1. Since it can be performed by a method that does not change (normal temperature conditions), sealing and insulating properties are ensured.

If the dimension b is too short, the positive electrode / negative electrode terminal lead and the metal intermediate layer of the laminate film are likely to contact each other at the heat seal portion. When the dimension b (and the total length of the positive electrode / negative electrode terminal lead in the outer package: dimension a) is too long, the volume energy density of the energy storage device decreases. The dimension b is preferably 0.05 mm or more and 5.0 mm or less, and more preferably 0.1 mm or more and 3.0 mm or less. The dimension c of the first plane portion 31 is preferably 1.0 mm or greater and 3.0 mm or less.
Furthermore, since the force accompanying the impact is not easily transmitted to the ear portions 23 and 24, the backlash of the electrode laminate 2 inside the exterior body 1 can be reduced, so that the electrode active material is missing when the impact is applied by dropping or vibration. Can also be prevented.

[Third Embodiment]
FIG. 5 is a front view showing a third embodiment of the electricity storage device having the laminate film exterior body of the present invention.
This power storage element is a rectangular pouch-type non-aqueous lithium-type power storage element, and includes an exterior body 1, an electrode laminate 2, an electrolytic solution, a negative terminal lead 3, and a positive terminal lead 4. ing. The electrode laminate 2 and the electrolytic solution are accommodated in the exterior body 1.
One end of the negative electrode terminal lead 3 is connected to the ear portion 23 of the negative electrode plate of the electrode laminate 2, and the other end is drawn out of the exterior body 1 through the heat seal portion 11. One end of the positive electrode terminal lead 4 is connected to the ear portion 24 of the positive electrode plate of the electrode laminate 2, and the other end is drawn out of the exterior body 1 through the heat seal portion 11.

  As shown in FIG. 6, the outer package 1 includes a laminate film 5 in which a polypropylene film (heat-meltable resin layer) 51, an aluminum foil (metal intermediate layer) 52, and a nylon film 53 are laminated. It is formed by heat sealing as the innermost layer. As shown in FIG. 6, the electrode laminate 2 is formed by laminating a plurality of negative plates 21 and positive plates 22 with a separator 25 interposed therebetween.

  As shown in FIG. 6, the negative electrode terminal lead 3 is in surface contact with one surface 17 of two parallel surfaces 17, 18 facing each other in the thickness direction inside the exterior body 1 in the exterior body internal space. The first flat surface portion 31, the intermediate portion 32 bent from the first flat surface portion 31 and reaching the center portion in the thickness direction of the exterior body 1, and the first bent toward the heat seal portion 11 from the intermediate portion 32. 2 plane portions 33. Respective ears extending from the negative electrode plate 21 to the inner surface of the first flat portion 31 and a part of the intermediate portion 32 continuing to the first flat portion 31 (the surface opposite to the surface where the first flat portion 31 contacts the surface 17 of the exterior body 1) The end portions of the portion 23 are collectively fixed by ultrasonic welding, resistance welding, solder connection, silver solder connection, or the like.

  The positive electrode terminal lead 4 has a first flat surface portion 41 in surface contact with the other surface 18 of the two parallel surfaces 17, 18 facing each other in the thickness direction in the exterior body 1 in the interior space of the exterior body 1. And an intermediate part 42 bent from the first flat part 41 and reaching the central part in the thickness direction of the exterior body 1, and a second flat part 43 bent from the intermediate part 42 toward the heat seal part 11. . Each ear extending from the positive electrode plate 22 to the inner surface of the first flat portion 41 and a part of the intermediate portion 42 continuous with the first flat portion 41 (the surface opposite to the surface where the first flat portion 41 contacts the surface 18 of the exterior body 1). The ends of the portions 24 are collectively fixed by ultrasonic welding, resistance welding, solder connection, silver solder connection, or the like.

  According to the electricity storage device of this embodiment, when an impact is applied by dropping or vibration, the intermediate portion 32 of the negative electrode terminal lead 3 absorbs the impact, and the first flat portion 31 and the inside of the exterior body 1 Since the surface 17 and the surface contact each other, a frictional force acts between them, and the positive terminal lead 4 functions in the same manner, so that the force accompanying the impact is not easily transmitted to the ear portions 23 and 24. In addition, the first flat surface portion 31 of the negative electrode terminal lead 3 is in surface contact with one of the two opposing surfaces 17 on the inner side of the exterior body 1, and the first flat surface portion 41 of the positive electrode terminal lead 4 is in contact with the other surface. Since the surface 18 is in surface contact with each other, a frictional force can be obtained on both inner surfaces in the thickness direction, so that a higher impact resistance can be obtained than the electricity storage device of the second embodiment.

Moreover, the heat seal is made to be conventional by increasing the length (dimension b) starting from the boundary point (point on the line A) between the heat seal portion 11 of the second plane portion 33 and the inside of the exterior body 1. Since it can be performed by a method that does not change (normal temperature conditions), sealing and insulating properties are ensured.
If the dimension b is too short, the positive electrode / negative electrode terminal lead and the metal intermediate layer of the laminate film are likely to contact each other at the heat seal portion. When the dimension b (and the total length of the positive electrode / negative electrode terminal lead in the outer package: dimension a) is too long, the volume energy density of the energy storage device decreases. The dimension b is preferably 0.05 mm or more and 5.0 mm or less, and more preferably 0.1 mm or more and 3.0 mm or less. The dimension c of the first plane portion 31 is preferably 1.0 mm or greater and 3.0 mm or less.
Furthermore, since the force accompanying the impact is not easily transmitted to the ear portions 23 and 24, the backlash of the electrode laminate 2 inside the exterior body 1 can be reduced, so that the electrode active material is missing when the impact is applied by dropping or vibration. Can also be prevented.

[No. 1-1 to 1-4]
A non-aqueous lithium storage element having a cup-type laminate film outer package shown in FIG. 1 (and FIG. 2) was produced by the following method.
<Preparation of exterior member>
A laminate film 5 was prepared in which a polypropylene film (heat-meltable resin layer) 51 having a thickness of 80 μm, an aluminum foil (metal intermediate layer) 52 having a thickness of 40 μm, and a nylon film 53 having a thickness of 25 μm were laminated.

  First, a deep drawing process is performed on the laminate film 5 and the nylon film 53 side is projected in an area corresponding to the size of the electrode laminate 2 to be accommodated, whereby a rectangular cup having a length of 55 mm, a width of 100 mm, and a depth of about 4 mm is obtained. Part 15 was formed. Next, the area | region which consists of the 1st part including the rectangular cup part 15 of this laminate film 5 and its periphery, and the 2nd part superimposed on a 1st part was cut | judged with the predetermined dimension. The laminate member 5 composed of the first portion and the second portion is folded and overlapped at the boundary between both portions with the polypropylene film 51 side inward to form an exterior member.

<Preparation of positive electrode plate>
First, commercially available activated carbon (specific surface area by BET method is 2094 m ² / g) as a positive electrode active material, ketjen black as a conductive filler, polyvinylidene fluoride resin as a binder, and N-methylpyrrolidone as a solvent were prepared. . These were blended in a ratio of 81.8 parts by weight of activated carbon, 8.2 parts by weight of ketjen black, 10 parts by weight of polyvinylidene fluoride resin, and 230 parts by weight of N-methylpyrrolidone to prepare a slurry.
Next, this slurry was applied to both sides of an aluminum foil having a thickness of 35 μm and dried, and further subjected to press working and punching. In this manner, a positive electrode plate in which the positive electrode active material layer is formed with a long side of 98 mm, a short side of 48 mm, and a thickness of 145 μm, and a portion where the positive electrode active material layer is not formed at the end of the aluminum foil is provided as an ear. It was.

<Preparation of negative electrode plate>
First, using a commercially available activated carbon (specific surface area by BET method is 1955 m ² / g) and a coal-based pitch, a composite in which a carbonaceous material is deposited on the surface of activated carbon as a negative electrode active material by the following method. A porous material was prepared. Further, acetylene black was prepared as the conductive filler, polyvinylidene fluoride resin as the binder, and N-methylpyrrolidone as the solvent.

150 g of activated carbon was placed in a cage made of stainless steel mesh, and 300 g of coal-based pitch was placed in a stainless steel vat. The aforementioned basket was placed on the bat, and the bat was placed in an electric furnace (effective size in the furnace 300 mm × 300 mm × 300 mm) for heat treatment. Specifically, in a nitrogen atmosphere, the temperature was raised to 670 ° C. over 4 hours, maintained at the same temperature for 4 hours, and then cooled to 60 ° C. by natural cooling, and then the bat was removed from the furnace. The composite porous material thus obtained had a BET specific surface area of 255 m ² / g.

  By mixing and mixing these in a ratio of 83.4 parts by weight of the composite porous material, 8.3 parts by weight of acetylene black, 8.3 parts by weight of polyvinylidene fluoride resin, and 300 parts by weight of N-methylpyrrolidone, a slurry is obtained. Was prepared. Next, this slurry was applied to both sides of a copper foil having a thickness of 40 μm and dried, and further subjected to pressing and punching. In this way, a negative electrode plate in which a portion where the negative electrode active material layer is formed has a long side of 98 mm, a short side of 48 mm, and a thickness of 180 μm, and a portion where the negative electrode active material layer is not formed at the end of the copper foil is obtained. It was.

<Non-aqueous electrolyte>
A non-aqueous electrolyte was prepared by dissolving lithium hexafluorophosphate (LiPF ₆ ) at a concentration of 1.0 mol / L in a mixed solvent in which ethylene carbonate and propylene carbonate were mixed at a volume ratio of 1: 2. .
<Preparation of electrode laminate with leads>
A polyethylene microporous film is disposed between the obtained positive electrode plate and negative electrode plate as a separator (long side 100 mm, short side 50 mm), and 10 positive plates and 9 negative plates are positive / negative / positive ... positive / By laminating in the negative / positive order, an electrode laminate having 18 sets of counter electrodes of positive electrode active material layer / separator / negative electrode active material layer was obtained. Also, a strip-shaped aluminum plate having a thickness of 0.2 mm was prepared as a positive electrode terminal lead, and a strip-shaped nickel plate having a thickness of 0.2 mm was prepared as a negative electrode terminal lead.

  Subsequently, ten ears of each positive electrode plate of the obtained electrode laminate were stacked and fixed to one end in the length direction of the positive terminal lead by ultrasonic welding. Also, the nine ears of each negative electrode plate were stacked and fixed to one end in the length direction of the negative electrode terminal lead by ultrasonic welding. In the positive electrode and the negative electrode, the fixing surface of each ear portion with respect to each terminal lead was the same surface in the thickness direction. The outer dimensions of the electrode laminate with lead thus obtained, excluding the lead portion, were 50 mm long, 100 mm wide, and 4.1 mm thick.

  By forming the positive electrode terminal lead and the negative electrode terminal lead of the obtained electrode laminate with leads, the end portion to which the ear portion is fixed is shaped as shown in FIG. That is, for the negative terminal lead 3, the first flat portion 31 and the intermediate portion 32 are formed at the end portion to which the ear portion 23 is fixed. Although only the negative terminal lead 3 is shown in FIG. 2, the positive terminal lead 4 has the same shape.

<Assembly of storage element>
The electrode laminate with leads in which the leads are formed is placed in the rectangular cup portion 15 of the first part of the laminate film, and the other end of the negative terminal lead 3 and the other end of the positive terminal lead 4 are connected to the laminate film. It arrange | positioned outside the heat seal part 11 of the 1st part. Next, the second part was overlaid on the first part by folding the laminate film.

  Thus, the electrode laminate 2 is accommodated in the rectangular cup portion 15 in the exterior member, one end of the negative electrode lead 3 and the positive terminal lead 4 is disposed inside the exterior member, and the other end is outside the exterior member. The both sides of the boundary portion were covered with the laminate film 5. In this state, a portion (heat seal portion) 11 extending the leads 3 and 4 to the outside and a portion (heat seal portion) 13 on the opposite side parallel to the folding line were heat sealed. The heat sealing conditions are a heating temperature of 195 ° C., a heating time of 20 seconds, a seal width of 10 mm, and a pressure of 0.5 MPa. Thereby, the outer peripheral part of the exterior member was heat-sealed except for the heat seal part 12, and the exterior body 1 in which the heat seal part 12 was an opening was formed.

Subsequently, after injecting the non-aqueous electrolyte from the heat seal part 12, the heat seal part 12 was heat sealed. As a result, a nonaqueous lithium storage element having the structure shown in FIGS. 1 and 2 was completed.
Sample No. 1-1 has the structure of the first embodiment shown in FIG. 2 as the electric storage element, and dimensions a, b, and c are a = 4.0 mm, b = 3.0 mm, and c = A device having a height of 1.0 mm and an intermediate portion 32 having a height d of 4 mm was produced.

Sample No. 1-2 has the structure of the first embodiment shown in FIG. 2 as the electric storage element, and dimensions a, b, and c are a = 4.0 mm, b = 0.10 mm, and c = A sample having 2.0 mm and a height d of the intermediate portion 32 of 4 mm was produced.
Sample No. 1-3 has the structure of the first embodiment shown in FIG. 2 as the electric storage element, and the dimensions a, b, c are a = 4.0 mm, b = 0.05 mm, c = An intermediate portion 32 having a height d of 4.0 mm was produced.
Sample No. 1-4 has the structure of the first embodiment shown in FIG. 2 as the electricity storage element, and dimensions a, b, and c are a = 6.0 mm, b = 3.0 mm, and c = The intermediate part 32 having a height d of 4.0 mm was manufactured at 2.5 mm.

[No.1-5]
After producing the electrode laminate with leads by the same method as the electricity storage elements of No. 1-1 to 1-4, forming processing was performed on the lead for the positive electrode terminal and the lead for the negative electrode terminal of the obtained electrode laminate with lead. Did not do. By assembling the electricity storage device in the same manner as the electricity storage devices of No. 1-1 to 1-4 except that this is used, a front view corresponds to FIG. 1 and a partial cross-sectional view corresponds to FIG. A non-aqueous lithium storage element having a laminate film outer package was produced.
This sample corresponds to a conventional example of a non-aqueous lithium storage element having a cup-type laminate film outer package. The dimension a was 5.0 mm.

[No. 1-6]
After producing the electrode laminate with leads by the same method as the electricity storage elements of No. 1-1 to 1-4, forming processing was performed on the lead for the positive electrode terminal and the lead for the negative electrode terminal of the obtained electrode laminate with lead. By doing so, the ends on the ear side of both leads were formed into the shape shown in FIG. By assembling the electricity storage element in the same manner as the electricity storage elements No. 1-1 to 1-4 except that this is used, a front view corresponds to FIG. 1 and a partial cross-sectional view corresponds to FIG. A non-aqueous lithium storage element having a laminate film outer package was produced.

  This sample corresponds to an example in which the method of Patent Document 2 is applied. From the inner surface 16 (surface facing the cup bottom surface 15a) of the outer package 1 to the end of the negative electrode terminal lead 3 on the ear portion 23 side. A bent portion 34 that protrudes in a V shape toward 15a is formed. The dimension a was 5.0 mm, and the height e of the flexure 34 was 2.0 mm. A similar bent portion is formed in the positive terminal lead 4.

[No.1-7]
After producing the electrode laminate with leads by the same method as the electricity storage elements of No. 1-1 to 1-4, forming processing was performed on the lead for the positive electrode terminal and the lead for the negative electrode terminal of the obtained electrode laminate with lead. By doing so, the ends on the ear side of both leads were formed into the shape shown in FIG. By assembling the electricity storage device in the same manner as the electricity storage devices of No. 1-1 to 1-4 except that this is used, a front view corresponds to FIG. 1 and a partial cross-sectional view corresponds to FIG. A non-aqueous lithium storage element having a laminate film outer package was produced.

  The ends of the leads on both ends of the sample have the dimension b shown in FIG. 2 being 0 (that is, without the second flat portion 33), and closer to the heat seal portion 11 than the first flat portion 31. An inclined portion 35 is formed. The inclined portion 35 is bent from the first flat portion 31 toward the inner surface 16 (surface facing the cup bottom surface 15a) of the exterior body 1, and is a boundary point (line A) between the heat seal portion 11 and the interior of the exterior body 1. It extends diagonally to the upper point). The dimension a was 4.0 mm and the dimension c was 0.80 mm.

[No.1-8]
After producing the electrode laminate with leads by the same method as the electricity storage elements of No. 1-1 to 1-4, forming processing was performed on the lead for the positive electrode terminal and the lead for the negative electrode terminal of the obtained electrode laminate with lead. By doing so, the ends of both leads on the ear side were formed into the shape shown in FIG. By assembling the electricity storage element in the same manner as the electricity storage elements No. 1-1 to 1-4 except that this is used, a front view corresponds to FIG. 1 and a partial cross-sectional view corresponds to FIG. A non-aqueous lithium storage element having a laminate film outer package was produced.

  The ends of the leads on both ends of the sample have the dimension b shown in FIG. 2 being 0 (that is, without the second flat portion 33), and closer to the heat seal portion 11 than the first flat portion 31. An inclined portion 35 is formed. The inclined portion 35 bends from the first flat portion 31 to the inner surface 16 (surface facing the cup bottom surface 15a) of the exterior body 1 to the inside of the heat seal portion 11 (outside the point on the line A). It extends diagonally. The dimension a and the dimension c are the same as No. 1-7, and the distance f between the second bending point of the inclined portion 35 (the bending point on the opposite side of the first plane portion 31) and the point on the line A is 0.05 mm.

[performance test]
First, 20 power storage elements of Sample Nos. 1-1 to 1-8 were prepared, and the impedance between the aluminum foil 52 portion of the laminate film 5 and the negative terminal lead 3 and the positive terminal lead 4 was measured. The short circuit test was done by measuring. The results are shown in Table 1 below. Table 1 shows the number of short circuits among the 20 pieces.

Moreover, after preparing 20 electricity storage elements of sample Nos. 1-1 to 1-6 and charging them to 4 V under an environment of 25 ° C., each of these electricity storage elements is placed in a simple pack made of resin. I put it in. A vertical drop test was performed in which these packs were dropped onto concrete from a height of 1.2 m.
As shown in FIG. 1, the negative electrode terminal lead 3 and the positive electrode terminal lead 4 protrude from the heat seal portion 11 of the outer package 1 having a rectangular planar shape, as shown in FIG. Shape. The vertical drop test is repeated 12 times with the end face along one side of the four sides of the rectangle facing down, and this is repeated by changing the end face facing down to the end face along the other three sides. A total of 48 vertical drop tests were conducted.
After the vertical drop test, the voltage (V) of each power storage element was measured, the impedance of the element for which the voltage could be measured was measured, and the amount of change in impedance (δZ) before and after the test was calculated.

As a result, the power storage elements No. 1-1 to 1-4 were capable of voltage measurement with all 20 power storage elements, and none of the power storage elements increased in impedance by 5% or more. On the other hand, the No. 1-5 power storage element has 6 power storage elements in which voltage measurement was possible and 14 power storage elements in which voltage measurement could not be performed. There were two power storage elements with an increase of 5% or more, and four power storage elements with an impedance increase of less than 5%.
The No. 1-6 power storage element has 19 power storage elements whose voltage could be measured and 1 power storage element which could not be measured. Of the 19 power storage elements whose voltage could be measured, the impedance was 5%. There were 6 electricity storage elements that had risen above, and 13 electricity storage elements that had an increase in impedance of less than 5%. These results are also shown in Table 1 below.

As shown in Table 1, No. 1-1 to 1-4 power storage elements corresponding to the embodiments of the present invention are all 20 pieces except for No. 1-3 whose dimension b is as short as 0.05 mm. No short circuit occurred in both the positive electrode and the negative electrode, but the short circuit occurred in the negative electrodes of the two power storage elements in the No. 1-3 power storage element. Moreover, as mentioned above, the result of the drop test about the electricity storage elements No. 1-1 to 1-4 was good.
The No. 1-5 storage element, which is a conventional example of a cup-type non-aqueous lithium storage element, had good short-circuit test results, but the drop test results were poor, and the impact resistance was insufficient. there were. The No. 1-6 power storage element to which the method of Patent Document 2 was applied had a good short-circuit test result, but the drop test result was inferior to the No. 1-1 to 1-4 power storage elements. Impact resistance was insufficient.

The electricity storage device of No. 1-7 does not have the second plane portion, and the second bending point of the inclined portion 35 is on the line A. Therefore, the aluminum foil 52, the positive electrode A short circuit with the lead for the negative electrode terminal occurred.
The electricity storage device of No. 1-8 does not have the second flat portion, and the second bending point of the inclined portion 35 is in the heat seal portion 11, so that the aluminum foil 52 and the negative electrode terminal are included in all the electricity storage devices. As a result, a short circuit occurred between the aluminum foil 52 and the positive electrode terminal lead in 18 of the 20 storage elements.
From the above results, the power storage elements No. 1-1 to 1-4 are superior to the power storage elements No. 1-5 to 1-8 in terms of both impact resistance and insulation. I understand that.

DESCRIPTION OF SYMBOLS 1 Exterior body 11 Heat seal part 11a of positive electrode terminal lead and negative electrode terminal lead Heat seal part 11b of negative electrode terminal lead Heat seal part 12 of positive electrode terminal lead Heat seal part 13 Heat seal part 14 Heat seal part 15 Rectangular cup Part 15a Cup bottom surface 16 Inner surface 17 facing the cup bottom surface Inner surface of the exterior body (one of the two surfaces facing in the thickness direction)
18 Inner surface of the exterior body (the other surface of the two surfaces facing each other in the thickness direction)
2 Electrode Stack 21 Negative Electrode Plate 22 Positive Electrode Plate 23 Negative Electrode 24 Positive Electrode Ear 25 Separator 3 Negative Terminal Lead 31 First Flat Part 32 Negative Terminal Lead Intermediate Port 33 Negative Terminal Second flat portion of lead 34 Bending portion 35 of lead for negative electrode terminal Inclined portion 4 of lead for negative electrode terminal 41 Lead 41 for positive electrode terminal First flat portion 42 of lead for positive terminal 42 Intermediate portion 43 of lead for positive terminal Second flat portion 5 of the lead for the laminate 5 Laminate film 51 Polypropylene film (heat-meltable resin layer)
52 Aluminum foil (metal intermediate layer)
53 Nylon film

Claims (5)

A laminate film having a metal intermediate layer and a heat-meltable resin layer heat-sealed with the heat-meltable resin layer as the innermost layer, and having a cup-shaped portion on one surface in the thickness direction When,
An electrode laminate in which a plurality of positive and negative electrode plates housed in the exterior body are laminated with a separator interposed therebetween, and
An electrolyte contained in the exterior body;
One end, the ends of the respective ears extending from the plurality of positive plates are fixed together, and the other end is a positive terminal lead that is drawn out of the exterior body through a heat seal portion,
The ends of the respective ears extending from the plurality of negative electrode plates are fixed together at one end, and the other end has a negative electrode terminal lead drawn out to the outside of the exterior body through a heat seal part. ,
Each of the positive terminal lead and the negative terminal lead includes a first flat portion that is in surface contact with the cup bottom surface in the outer package, and a cup bottom surface bent from the first flat portion in the outer space of the outer package. A cup bottom surface of the first flat surface portion, having an intermediate portion reaching the inner surface of the facing exterior body, and a second flat portion bent from the intermediate portion and contacting the inner surface while facing the heat seal portion An electric storage element having a laminate film outer package, wherein ends of the respective ear portions are fixed together on a surface opposite to a surface in contact with. An outer package in which a laminate film having a metal intermediate layer and a heat-meltable resin layer is heat-sealed using the heat-meltable resin layer as an innermost layer, and a heat-seal portion is formed at the center in the thickness direction When,
An electrode laminate in which a plurality of positive and negative electrode plates housed in the exterior body are laminated with a separator interposed therebetween, and
An electrolyte contained in the exterior body;
One end, the ends of the respective ears extending from the plurality of positive plates are fixed together, and the other end is a positive terminal lead that is drawn out of the exterior body through a heat seal portion,
The ends of the respective ears extending from the plurality of negative electrode plates are fixed together at one end, and the other end has a negative electrode terminal lead drawn out to the outside of the exterior body through a heat seal part. ,
The positive electrode terminal lead and the negative electrode terminal lead each have a first plane portion in surface contact with one of two parallel or substantially parallel surfaces facing each other in the thickness direction in the exterior body in the interior space of the exterior body. An intermediate portion that bends from the first flat portion and reaches the central portion in the thickness direction of the exterior body, and a second flat portion that is bent from the intermediate portion and faces the heat seal portion, An electric storage element having a laminate film outer package, wherein ends of the respective ear portions are fixed together on a surface opposite to a surface contacting one of the two surfaces of the flat portion.   The laminate according to claim 2, wherein the first flat surface portion of the positive electrode terminal lead is in surface contact with one of the two surfaces, and the first flat surface portion of the negative electrode terminal lead is in surface contact with the other of the two surfaces. A power storage element having a film outer package.   The negative electrode terminal lead is formed into a plate shape having a thickness of 0.08 to 0.5 mm by any one of nickel, nickel alloy, copper, nickel-plated copper, and a clad material made of copper and nickel. The electrical storage element which has the laminate film exterior body of any one of Claims 1-3 which is formed.   The laminate film exterior according to any one of claims 1 to 4, wherein the positive terminal lead is formed of aluminum or an aluminum alloy into a plate shape having a thickness of 0.08 to 0.5 mm. A power storage element having a body.

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