JP2002280273A - Electrochemical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochemical element, with which a safety valve is surely actuated with a prescribed pressure and service life can be prolonged, by delaying the time until the safety valve is operated. SOLUTION: An electrode laminate 6, with which a pair of polarized electrodes 3a and 3b are located via a separator 2 and a pair of collectors 4a and 4b are located on the respective outer surfaces of the polarized electrodes 3a and 3b, is housed inside an outer member 8, and the inside of the outer member 8 is sealed airtightly by immersing the inside of the electrode laminate 6 with an electrolyte. In such an electrochemical element, such as an electric double-layer capacitor 1, a through-hole 10 is provided on the outer member 8 and the electric double layer capacitor 1 is produced for sealing the outer member 8 by sticking an elastic layer 13 on the inner wall surface of the outer member 8 so that a portion, where the through-hole 10 is formed, can be covered and a space 11 can be provided in a gap with the inner wall surface of the outer member 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrochemical device capable of guaranteeing a stable operation for a long time.

[0002]

2. Description of the Related Art As an electrochemical element which is a power storage device,
A pair of polarizable electrodes are disposed via a separator, and an electrode laminate in which a pair of current collectors is disposed on each of outer surfaces of the polarizable electrodes is housed in an exterior material such as a metal housing, and the electrode There is known an electric double-layer capacitor having a configuration in which a laminate is impregnated with an electrolytic solution to hermetically seal the inside of the exterior material.

An electric double layer capacitor utilizes electric energy generated by electric charges accumulated in an electric double layer formed at an interface between a polarizable electrode and an electrolyte, and has a small capacity such as a backup for an integrated circuit memory. In recent years, attention has been paid to the fact that rapid charging and discharging are possible and stable against repeated charging and discharging. Recently, application to power applications such as a power supply for motor driving has been promoted. I have.

When such an electrochemical element such as an electric double layer capacitor is operated for a long time, the electrodes such as the polarizable electrode and the electrolytic solution are deteriorated to generate a decomposition gas. As a result, the internal pressure inside the exterior material is increased. It is known that the exterior material may eventually burst.

Therefore, for example, Japanese Patent Application Laid-Open No. 10-22181
In the gazette, a groove-shaped thin portion is formed on the bottom wall surface of an aluminum case, which is an exterior material, and a thick swelled portion is formed at an intersection of the thin portion, so that the internal pressure of the exterior material is a specified value. At the stage of reaching, the thin part is torn, and a case for a capacitor functioning as an explosion-proof valve is described. In JP-A-11-162798,
An electric double layer capacitor having a safety valve having a structure in which a through hole is provided and the through hole is sealed with a pressure plate such as an aluminum foil is described, and when the internal pressure of the exterior material reaches a specified value, the pressure plate portion is It is disclosed that gas generated inside the exterior material by rupture can be released.

[0006]

However, in an aluminum case having an explosion-proof valve described in Japanese Patent Application Laid-Open No. 10-22181, it is necessary to process the exterior material wall into a complicated shape, which not only increases the cost but also increases the cost. It has been difficult to adjust the thickness of the thin portion so that the thin portion is broken at a predetermined pressure. Further, in the electric double layer capacitor described in Japanese Patent Application Laid-Open No. H11-162798, since the internal pressure of the exterior material increases by the amount of generated gas, the safety valve operates at a relatively early stage to break the pressure plate. As a result, there is a problem that the life of the electric double layer capacitor is shortened.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a safety valve that can operate reliably at a predetermined pressure and that can prolong the service life by delaying the time until the safety valve operates. It is to provide a chemical element.

[0008]

As a result of studying the structure of the safety valve of the electrochemical element, the present inventors have provided a through hole in the exterior material, and provided the through hole forming portion on the inner wall surface of the exterior material. By covering and sealing the exterior material by attaching an elastic layer so as to have a space between the inner wall surface of the exterior material, the volume of the space between the wall surface of the exterior material and the elastic layer is reduced. A large amount of generated gas can be accumulated in the exterior material, the internal pressure of the exterior material can be delayed from reaching the specified value, the life of the electric double layer capacitor can be extended, and the interior material can be stored without complicated processing. The safety layer can be reliably operated at a predetermined pressure because the elastic layer can be easily adjusted so that the elastic layer is inflated by the gas accumulated in the gasket and ruptured by the elastic layer when the interior material reaches a predetermined pressure. Was found.

That is, in the electrochemical device of the present invention, a pair of electrodes are arranged via a separator, and an electrode laminate in which a pair of current collectors is arranged on each of the outer surfaces of the electrodes is housed in an exterior material. An electrolyte is impregnated in the electrode laminate to hermetically seal the interior of the exterior material, and a through hole is provided in the exterior material, and on the inner wall surface of the exterior material,
An exterior material is sealed by covering an elastic layer so as to cover the through-hole forming portion and to have a space between itself and the inner wall surface of the exterior material.

[0010] Here, it and the volume V _t excluding the electrode stack within the outer member, the ratio of the volume V _s of the space portion (V _s / V _t) is 0.5 to 0.95, The ratio of the opening area S _h of the through hole of the exterior material to the area S _{s of the} surface in contact with the interior wall surface of the exterior material in the space formed between the inner wall surface of the exterior material and the elastic layer. _{(S h} / S _s) is 0.03
0.9 is desirable.

It is preferable that the exterior material includes an exterior container and a lid, and the elastic layer is attached to an inner wall surface of the lid.

Further, the elastic layer comprises a laminate of a metal layer and a resin layer coated on the electrode laminate side of the metal layer, wherein the resin layer is selected from the group consisting of polyethylene, polypropylene, polyethylene terephthalate and polyimide. Desirably, it consists of at least one selected from.

Further, the outer periphery of the elastic layer is welded and attached to the inner wall surface of the exterior material, and the elastic layer has a thickness of 0.1 mm.
It is desirable that the thickness is 02 to 0.3 mm, and a thin portion is provided in a part of the elastic layer.

[0014] Further, a second through-hole penetrating the exterior material and the elastic layer is provided, and a lead terminal electrically connected to the current collector is passed through the through-hole. It is preferable that a gap between the second through hole formed in the elastic layer and the peripheral edge of the second through hole through which the lead terminal of the elastic layer passes is welded to the inner wall surface of the exterior material. .

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The electrochemical device of the present invention is described below.
An example of an electric double layer capacitor as a representative example will be described with reference to FIG. 1 which is a schematic cross-sectional view. According to FIG. 1, an electric double layer capacitor 1 includes a pair of polarizable electrodes 3a, 3b forming a positive electrode and a negative electrode via a separator 2.
And a pair of current collectors 4a, 4 forming a positive electrode and a negative electrode on the outer surfaces of the polarizable electrodes 3a, 3b, respectively.
b is accommodated in the exterior material 8, and the electrode laminate 6 is impregnated with an electrolytic solution to form the exterior material 8.
The inside is hermetically sealed.

As shown in FIG. 1, the electrode laminate 6 includes a plate-like separator 2, a polarizable electrode 3 and a current collector 4, and a current collector 4-polarizable electrode 3-separator 2-separator. A plurality of layers may be laminated in the order of the polar electrode 3 and the current collector 4, or a long sheet-shaped separator 2, the polarizable electrode 3 and the current collector 4 may be replaced with the current collector 4 and the polarizable electrode 4. These may be wound while being laminated in the order of 3-separator 2.

According to the present invention, the through hole 10 is provided on the wall surface of the exterior material 8 and the through hole 1 is provided on the inner wall surface of the exterior material 8.
It is a great feature that the elastic layer 13 is attached so as to cover the formation portion 0 and to have the space portion 11 between the outer material 8 and the inner wall surface, thereby sealing the outer material 8. The extra gas generated by the volume of the space 11 between the wall surface of the elastic member 8 and the elastic layer 13 can be accumulated in the exterior material 8,
When the internal pressure of the exterior material 8 increases due to the generation of gas, the elastic layer 13 forms the exterior material 8.
Can be easily adjusted so as to protrude toward the inside of the through-hole 10 toward the outside of the through hole 10 and eventually burst at the swollen portion of the elastic layer 13, without requiring any complicated processing or the like. In addition, the safety valve 14 can be reliably operated at a predetermined pressure.

Here, in order to increase the gas storage capacity in the space 11 and to reduce the volume of the exterior material to reduce the size of the electric double-layer capacitor 1, the electrode laminate 6 in the exterior material 8 must be formed. the volume V _t, excluding the ratio of the volume V _s of the space portion 11 (V _s / V _t) is 0.5 to 0.95, especially 0.55 to 0.
9, and more preferably 0.6 to 0.8.

Also, in order to increase the gas storage capacity in the space 11, to prevent air bubbles from remaining inside the exterior material 8, and to allow the elastic layer 13 to easily project into the through hole 10. Thus, the opening area S _h of the through hole 10 of the exterior material 8
(Πr ₁ ^{2 in} FIG. 2), and the area S _{s of the} surface of the space 11 formed between the inner wall surface of the exterior material 8 and the elastic layer 13 that contacts the inner wall surface of the exterior material 8 (πr ₂ ^{2 in} FIG. 2). ) And the ratio (S _h /
S _s ) is preferably from 0.03 to 0.9, particularly preferably from 0.1 to 0.3.

Further, the exterior material 8 is desirably formed of a container having high heat resistance and rigidity such as a metal case in terms of heat resistance, and such a container is easy to manufacture and has a sealing property inside the exterior material. In this respect, it is desirable that the outer container 8A and the lid 8B be formed. Further, in this case, the through-hole 10 and the elastic layer 13 may be formed on the side surface of the outer container 8A, but in that the desired space 11 can be easily formed.
It is desirable that the elastic layer 13 is attached to the inner wall surface of the lid 8B.

According to the present invention, the volume ratio (V _s
/ A V _t ratio) to the above range, the outer package 8 and the elastic layer 13 as shown in FIG. 2, the second through hole 15 that penetrates both provided in the through hole 15 of the second Lead terminal 1
6 and a structure that seals a gap between the lead terminal 16 and the second through hole 15 formed in the elastic layer 13. The lead terminal 16 is electrically connected to a terminal portion 4A formed at one end of the current collector 4 by welding or the like.

In order to seal the gap between the lead terminal 16 and the second through hole 15 formed in the elastic layer 13, the elastic layer 13 and the second through the lead terminal 16 of the elastic layer 13 are sealed. The space between the elastic layer 13 and the through hole 15 may be directly bonded.
In consideration of the function as the safety valve 14, it is desirable to weld the peripheral edge of the second through hole 15 of the elastic layer 13 to the inner wall surface of the exterior material 8 (welded portion 17).

Further, as a method of attaching the elastic layer 13 to the inner wall surface of the exterior material 8 and sealing it, the outer periphery of the elastic layer 13 is It is desirable to use a welding method. As the welding method, laser welding, electron beam welding, resistance welding, and the like can be applied. However, it is desirable to perform laser welding, in particular, in that airtightness is enhanced and processing can be performed with high dimensional accuracy.

On the other hand, as shown in FIG.
It is desirable to form a so-called laminate film composed of a metal layer 19 and a laminate of the resin layer 20 coated on the electrode laminate 6 side of the metal layer 19, and further, the resin layer 20 is in contact with an electrolytic solution. Also selected from the group of polyethylene, polypropylene, polyethylene terephthalate and polyimide, in that it has a high electrical stability, a high insulation property, and can be prepared to be reliably broken when the internal pressure of the exterior material 8 reaches a specified value. It is desirable that it be composed of at least one of the following. In addition, when the elastic layer 13 is formed of a laminate film and the elastic layer 13 is welded to the inner wall surface of the exterior material 8, the resin layer 20 is attached to the welded portion 17 welded to the exterior material 8 of the laminate film. Metal layer 1 removed
Desirably, it is in a 9-bare state.

The metal layer 19 of the elastic layer 13 is preferably made of at least one metal selected from the group consisting of aluminum, stainless steel, and copper. Desirably, it is made of foil.

According to the present invention, the elastic layer 13 is not limited to a laminate film, but may be a metal layer such as an aluminum foil. Then, it is desirable to be made of a laminated film.

The thickness of the elastic layer 13 is adjusted so that the elastic layer 13 can be formed without defects such as pinholes and cracks, and is adjusted so as to be reliably broken when the internal pressure of the exterior material 8 reaches a specified value. 02-3mm, especially 0.05-3mm
It is desirable that

Further, in order to make it possible to adjust the predetermined position so as to be surely torn at a specified pressure, a thin portion 21 may be provided at a part of the elastic layer 13, particularly at a position facing the through hole 10 of the exterior material 8. Good.

The elastic layer 13 has, for example, an internal pressure of the exterior material 8 of 1.5 × 10 ^{5 to} 2.0 × 10 ⁶ Pa.
The adjustment to explode at the time when the pressure reaches the specified pressure of 5 × 10 ^{5 to} 1.0 × 10 ⁶ Pa is considered to be the safety of the electric double layer capacitor 1 and the area around the lead terminal 16 forming portion of the exterior material 8. From the viewpoint of preventing the liquid from leaking.

(Structure of Each Layer) On the other hand, the activated carbonaceous structure constituting the polarizable electrode 3 is made of particles or fibrous activated carbon having a high specific surface area, polyethylene terephthalate (PTFE) for bonding between the activated carbons, or the like. It may be a mixture of a binder such as polyvinyl butyral and a conductive material such as Ketjen black or acetylene black, if desired, which may be carbonized.

Also, maintaining a high capacitance of the capacitor,
In order to obtain the necessary strength as a structure, the activated carbon preferably has a specific surface area of 1000 to 2000 m ² / g.

The binder is, for example, activated carbon 10
0 parts by weight, a total amount of 5 to 40 parts by weight is present between the activated carbons, but when carbonization is performed, the ratio of the carbon component of the binder in the activated carbonaceous structure Is preferably 5 to 50% by weight, whereby the sinterability and bonding between the activated carbon particles can be enhanced.

The polarizable electrode 3 has a thickness of 0.02-1.
It is desirably formed in a plate shape or a long sheet shape of 5 mm, particularly 0.05 to 1 mm.

The separator 2 is made of pulp, polyethylene, polypropylene, polyvinylidene fluoride (P
An organic film such as VdF), a glass fiber nonwoven fabric, and ceramics can be used. The organic film is formed to insulate between adjacent polarizable electrodes 3a and 3b forming different polarities. It is formed of a porous body that can transmit ions in the electrolyte contained in the electrolyte. The thickness of the separator 2 is desirably 0.02 to 0.15 mm in order to prevent short circuit due to breakage or the like and to reduce the internal resistance of the electric double layer capacitor 1.

Further, the polarizable electrode 3 and the separator 2
Inside are aqueous solutions such as sulfuric acid and nitric acid, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), and γ-butyrolactone (γ-
BL), N, N-dimethylformamide, sulfolane,
A non-aqueous electrolyte in which a non-aqueous solvent such as 3-methylsulfolane and an electrolyte such as a quaternary ammonium salt, a quaternary sulfonium salt, and a quaternary phosphonium salt are combined is impregnated. It is desirable to use an electrolyte. The amount of the electrolyte dissolved in the non-aqueous solvent is preferably 0.5 mol / l to 2.0 mol / l from the viewpoint of obtaining a stable and high capacitance.

The current collector 4 is formed of a conductive metal foil such as aluminum, titanium, tantalum, platinum, or gold, or stainless steel, and exchanges electric charge with the polarizable electrode 3. In particular, it is desirable to use a metal foil mainly composed of aluminum from the viewpoint of corrosion resistance to a non-aqueous electrolyte having a high decomposition voltage. The thickness of the current collector 4 is preferably thin in order to reduce the internal resistance.
Preferably, the terminal portion 4A for exchanging electric charges inside and outside the electrode laminate 6 is formed on the periphery of the current collector 4.

The exterior material 8 is formed of a box-like body or a bag-like body, and encloses a cell laminate of the polarizable electrode 3, the separator 2, and the current collector 4 except for a part of the terminal portion. Although it has a barrier function against the outside air and moisture, the present invention is particularly effective when it is made of a box such as a cylindrical can or a square tubular can in that the volume of the space can be secured.

Further, as the exterior material 8, for example, aluminum, titanium, platinum, stainless steel, etc. can be used, but it is particularly preferable to use aluminum which is low cost and lightweight. The exterior member 8 is formed of a member having higher rigidity than the elastic layer 13.

According to the present invention, besides the above-described electric double-layer capacitor 1, the present invention is applicable to, for example, an electrolytic capacitor and a lithium battery. This is particularly effective for the electric double layer capacitor 1 in that the polarizable electrode 3 and the electrolytic solution) deteriorate and the electrolytic solution is easily vaporized.

(Manufacturing Method) Next, as an example of a method of manufacturing the electrochemical device of the present invention, a method of manufacturing the above-described electric double layer capacitor will be described. First, a polarizable electrode made of a plate-like activated carbonaceous structure, a separator, and a current collector are prepared, and are stacked in the order described above, or a long sheet-shaped polarizable electrode, a separator, and a current collector are formed as described above. The electrode laminate is manufactured by winding the layers while laminating them in the order given.

On the other hand, an elastic layer is attached by laser welding or the like to the inner wall surface of the exterior material having a through hole in the wall surface as described above. At this time, it is desirable that the exterior material be composed of an exterior container and a lid in terms of ease of attaching the elastic layer.

Further, it is desirable that a convex portion for forming a space between the elastic layer and the exterior material is formed in advance in the elastic layer. In addition, as a method of forming the space portion, in addition to the above, after attaching the elastic layer to the inner wall surface of the exterior material in a slack state, the gas or the like is supplied from the through hole of the exterior material to expand the elastic layer. Alternatively, a method of forming a space may be used.

Further, a second through hole may be formed in the exterior material first, and a lead terminal may be inserted to fill the gap therebetween.

Next, while accommodating the electrode laminate in the package, an electrolyte is injected into the electrode laminate. At this time, the terminal portions of the current collector protruding from the electrode laminate are converged at the terminal portions having the same polarity and welded to the lead terminals protruding into the exterior material, thereby electrically connecting the electrode laminate and the lead terminals. Connection. Further, when injecting the electrolyte into the electrode laminate, it is desirable to remove the gas in the electrode laminate once by evacuation or the like and then inject the gas to reduce the amount of gas present in the exterior material.

Then, the electric double layer capacitor can be manufactured by closing the lid of the exterior material or the electrolyte injection port.

[0046]

(Example 1) 10 parts by weight of Ketjen black and 1 part of polyfluoroethylene (PTFE) per 100 parts by weight of an activated carbon powder sample having a BET value of 2000 m ² / g.
After adding and mixing 0 parts by weight and stirring with a high-speed mixing stirrer, the obtained powder was subjected to a mesh pass with 40 mesh,
A sheet-shaped compact was prepared by roll forming and cut to prepare a long sheet-like activated carbonaceous structure (polarizable electrode) having a width of 100 mm and a thickness of 0.3 mm.

Further, a current collector made of an aluminum foil having a width of 100 mm and a thickness of 50 μm and having a terminal portion having a width of 30 mm at one end was prepared. Further, a separator made of cellulose pulp having a width of 105 mm and a thickness of 50 μm was prepared.

Then, a long sheet of the polarizable electrode, the current collector, and the separator was wound in a state where the current collector, the polarizable electrode, and the separator were laminated in this order to prepare an electrode laminate.

On the other hand, an outer container made of aluminum and having an inner volume of 48 mm in diameter × 12.5 mm in height and having a thickness of 0.8 mm and a diameter of 48 mm × 2 mm in thickness
Prepare a lid body, one through hole with a diameter of 3mm in the lid body,
Two second through holes for a lead terminal having a diameter of 9 mm were drilled, and a lead terminal having a diameter of 9 mm was inserted into the second through hole to seal the gap.

Further, a thickness of 50 is formed on one surface of the lid.
μm aluminum foil-10 μm thick resin layer made of polypropylene, total thickness 60 μm and volume 13 cm ³
Having a convex portion (space portion) having a peripheral portion of 2 mm
1 and 2 in which the aluminum foil was exposed without being covered with the first and second resin layers.

The laminate film is provided with two second through holes for penetrating the lead terminals of the lid, and the periphery of the second through hole is also in a state where the aluminum foil is exposed. . Then, the periphery of the laminate film and the periphery of the second through hole were laser-welded to one surface of the lid of the exterior material.

Next, the above-mentioned electrode laminate is housed in the above-mentioned outer container, and after evacuating the inside of the outer material, propylene of 1 mol / l tetraethylammonium tetrafluoroborate (Et ₄ NBF ₄ ) is placed in the outer container. A carbonate (PC) solution was injected as an electrolyte. Then, the lid of the exterior material was caulked to the exterior material container via a polyethylene packing and sealed, thereby producing an electric double layer capacitor.

The impedance of the obtained electric double layer capacitors at 10 kHz was measured as an internal resistance and found to be 1.5 mΩ on average. Also, 70
The internal resistance after charging for 1000 hours at a temperature of 2.5 ° C. and a current of 5 A was 1.8 mΩ. In addition, 70
When charging was performed at 3.0 ° C. and 3.0 V for 600 ± 50 hours, the laminate film protruded outside from the through hole of the exterior material lid, and burst from the protruding portion.

(Comparative Example 1) A laminate film was produced in the same manner as in the example except that the laminate film of the example was formed of an aluminum foil having a thickness of 0.05 mm without forming a convex portion, and evaluated in the same manner as in the example. Was measured as an internal resistance and found to be an average of 1.5 mΩ. The internal resistance after charging for 1000 hours at 70 ° C., 2.5 V and a current of 5 A was 2.2 mΩ on average.
Further, at the time when the charge and discharge were repeated for 400 ± 60 hours, the laminate film protruded outside from the through hole of the exterior material lid, and burst from the protruding portion.

(Comparative Example 2) A sample was produced in the same manner as in the example except that the through-hole and the laminated film were not formed in the exterior material of the example, and evaluated in the same manner as in the example. The impedance at 1 kHz was measured as the internal resistance. However, the average was 1.5 mΩ. The internal resistance after charging for 1000 hours at 70 ° C., 2.5 V and a current of 5 A was 2.5 mΩ on average. Further, when the battery was further charged at 70 ° C. and 3.0 V for 600 ± 130 hours, the electrolyte solution had leaked out from the periphery of the lead terminal forming portion of the exterior material lid.

[0056]

As described in detail above, according to the present invention,
The exterior material is provided with a through hole, and an elastic layer is attached to an inner wall surface of the exterior material so as to cover the through hole forming portion and to have a space between the interior material and the inner wall surface. By sealing the material, a large amount of gas generated in the extra volume of the space between the wall surface of the exterior material and the elastic layer can be accumulated in the exterior material, delaying the internal pressure of the exterior material from reaching a specified value. It can extend the life of the electric double layer capacitor and can be easily adjusted to burst in the elastic layer without requiring complicated processing etc. it can.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of an electric double-layer capacitor which is a preferred example of an electrochemical device of the present invention.

FIG. 2 is a plan view for explaining a shape of an elastic layer in the electric double layer capacitor of FIG.

FIG. 3 is a schematic diagram for explaining a configuration of an elastic layer of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric double layer capacitor 2 Separator 3 (3a, 3b) Polarizing electrode 4 (4a, 4b) Current collector 4A Terminal part 6 Electrode laminated body 8 Exterior material 10 Through hole 11 Space part 13 Elastic layer 14 Safety valve 15 Second Through hole 16 Lead terminal 17 Weld 19 Metal layer 20 Resin layer 21 Thin part

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Makoto Higashi Beppu 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima F-term in Kyocera Research Institute (reference) 5H011 AA13 CC02 CC06 CC10 DD13 5H012 AA01 BB02 DD01 DD05 DD06 EE01 EE04 EE09 FF01 GG01 JJ02 JJ10

Claims (11)

[Claims] An electrode laminate having a pair of electrodes disposed on a separator and a pair of current collectors disposed on outer surfaces of the electrodes, respectively, is housed in an exterior material, and an electrolytic solution is provided in the electrode laminate. Wherein the exterior material is hermetically sealed, wherein the exterior material is provided with a through-hole, the inner wall surface of the exterior material covers the through-hole forming portion, and the exterior material An electrochemical element, characterized in that an elastic layer is attached so as to have a space between itself and an inner wall surface, and an exterior material is sealed. 2. A volume V _t excluding an electrode laminate in the exterior material.
When the ratio of the volume V _s of the space portion (V _s / V _t) of 0.5
The electrochemical device according to claim 1, wherein the ratio is from 0.95 to 0.95. And the opening area S _h of 3. A through hole of the outer member, the area of the inner wall surface in contact with a surface of the outer member in the space formed between the inner wall and the elastic layer of the outer package S
_The electrochemical device according to claim 1, wherein a ratio (S _h / S _s ) to _s is 0.03 to 0.9. 4. The exterior material comprises an exterior container and a lid,
The electrochemical device according to any one of claims 1 to 3, wherein the elastic layer is attached to an inner wall surface of the lid. 5. The electrochemical device according to claim 1, wherein the elastic layer comprises a laminate of a metal layer and a resin layer coated on the electrode laminate side of the metal layer. element. 6. The electrochemical device according to claim 5, wherein said resin layer is made of at least one selected from the group consisting of polyethylene, polypropylene, polyethylene terephthalate and polyimide. 7. The electrochemical device according to claim 1, wherein an outer periphery of the elastic layer is welded and attached to an inner wall surface of the exterior material. 8. The elastic layer has a thickness of 0.02 to 0.3 mm.
The electrochemical device according to any one of claims 1 to 7, wherein 9. The electrochemical device according to claim 1, wherein a thin portion is provided in a part of the elastic layer. 10. A second member penetrating the exterior material and the elastic layer.
And a lead terminal electrically connected to the current collector is passed through the through hole, and a gap between the lead terminal and the second through hole formed in the elastic layer is sealed. The electrochemical device according to any one of claims 1 to 9, wherein: 11. The electrochemical device according to claim 10, wherein a peripheral edge of the second through-hole through which the lead terminal of the elastic layer passes is welded and sealed to an inner wall surface of the exterior material.