JP4658683B2 - Electrochemical element - Google Patents

Description

  The present invention relates to an electrochemical element configured by laminating a plurality of electrode sheets and separators.

Generally, negative or positive charges are alternately stored in each electrode sheet by alternately laminating electrode sheets having electrode layers formed on both sides of a rectangular sheet-shaped current collector foil via insulating separators. Electrochemical elements that can be used are known. As such an electrochemical element, conventionally, one side of the electrode sheet that stores negative charges protrudes outward from the electrode layer or separator, and the other side of the electrode sheet that stores positive charges is opposite to the one side. It is known that the structure is simplified by projecting the sides outward from the electrode layer or the separator so that the negative charge outlet and the positive charge outlet are directed in opposite directions. (See Patent Document 1). Specifically, in this structure, a conductive shim (spacer) is sandwiched between the protruding portions, and each electrode is sandwiched between conductive “tags” having a U shape. Current is collected from the sheet.
JP-A-11-274004 (paragraph 0035, FIG. 3)

  However, since “Taga” in the prior art has a U-shape, it cannot be held by applying an appropriate pressure in the stacking direction to the stacked electrode sheets. Therefore, the adhesiveness between the current collector foil and the electrode layer is deteriorated, and the electric resistance may be increased.

  Therefore, it is conceivable to apply an appropriate pressing force to the laminated electrode sheets with a pair of plate members or the like from both sides in the lamination direction. However, when doing so, the distance between the electrode sheet located at the end and the plate member and the distance between the electrode sheet located second from the end and the plate member are shorter than the distance between the electrode sheets of the same polarity, so at least It is necessary to prepare three kinds of shims having different thicknesses, which causes a difficulty in assembling.

  In addition, in an electrochemical element in which electrode sheets are alternately stacked via insulating separators, there has been a demand for improving the insulation and improving the yield.

Therefore, in the present invention, it is a first object to provide an electrochemical element capable of applying an appropriate pressure in the stacking direction to the stacked electrode sheets and reducing the types of shims. .
In addition, a second problem is to provide an electrochemical element that can improve insulation and improve yield.

  The invention according to claim 1 of the present invention that solves the first problem comprises: a plurality of electrode sheets each having an electrode layer formed on a current collector foil; and a separator disposed between the electrode sheets. An electrochemical element in which the electrode layer and the separator are impregnated with an electrolyte, a current collecting wall for collecting current from a part of the plurality of electrode sheets, and an end of the laminated electrode sheets Two substantially L-shaped current collecting plates, each of which has an electrode sheet and a holding wall provided with a current extraction portion for taking out the current collected by the current collecting wall to the outside, A plurality of shims for sandwiching the electrode sheet in the stacking direction and holding the electrode sheet in a predetermined position are provided, and instead of the shim at the end of the holding wall of the current collecting plate on the current collecting wall side The stepped part becomes Made is characterized in that is.

  According to the first aspect of the present invention, the laminated electrode sheets are sandwiched in the laminating direction by the holding walls of two substantially L-shaped current collecting plates, and each electrode sheet is held in a good pressure state. The Rukoto. For this reason, the current collector foil and the electrode layer are brought into close contact with each other, so that the electric resistance can be lowered, and the capacitance can be increased.

Furthermore, since the step part which becomes a substitute of a shim is formed in the edge part by the side of the current collection wall of the holding wall in a current collection plate, it can eliminate a shim and can aim at reduction of a number of parts. If such a step portion is not formed, it is necessary to provide a shim between the holding wall and the electrode sheet adjacent to the holding wall. There is also a risk.
On the other hand, since the shim can be eliminated by a simple configuration in which the step portion is formed, the number of shims is reduced correspondingly, and the assembly can be easily performed, thereby preventing erroneous assembly.

The first invention according to 請 Motomeko 2 that solve the second problem simultaneously, a plurality of electrode sheets in which the electrode layer is formed on the current collector foil, a separator disposed between the electrode sheet An electrochemical element in which the electrode layer and the separator are impregnated with an electrolyte solution, a current collecting wall for collecting current from a part of the plurality of electrode sheets, and the stacked electrode sheets And two substantially L-shaped current collecting plates, each of which has an electrode sheet at the end and a holding wall provided with a current extraction portion for taking out the current collected by the current collecting wall to the outside. A plurality of shims for sandwiching the electrode sheet in the stacking direction and holding the electrode sheet in a predetermined position, and at the end of the current collecting plate on the current collecting wall side, the shim The stepped part instead of Together have been made, among the plurality of the shim, said shim for end adjacent the distal end portion of the current Denkabe in the collector plate is characterized in that it is formed of an insulating member.

According to the second aspect of the present invention, similarly to the case described in the first aspect, the stacked electrode sheets are sandwiched between the holding walls of the two substantially L-shaped current collecting plates in the stacking direction. Therefore, the current collector foil and the electrode layer are brought into close contact with each other, so that the electric resistance can be lowered and the capacitance can be increased.

  In addition, the simple structure of forming a stepped part that replaces the shim eliminates the shim, thereby reducing the number of parts. Since the shim can be eliminated, the number of shims is reduced, and assembly is also performed. An electrochemical device that is easy to prevent erroneous assembly can be obtained.

Further, according to the invention described in claim 2 , among the plurality of shims for holding the electrode sheet in a predetermined position, the end shim adjacent to the front end of the current collecting wall in the current collecting plate is: Since it is formed of an insulating member, it is possible to effectively prevent interference between charges of different polarities at a site where the different polar final power plates are close to each other.

ADVANTAGE OF THE INVENTION According to this invention, while being able to provide a moderate pressurizing force with respect to the laminated | stacked electrode sheet in a lamination direction, the electrochemical element which can reduce the kind of shim is obtained.
In addition, an electrochemical element capable of improving the yield and improving the yield can be obtained.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the drawings to be referred to, FIG. 1 is a cross-sectional view showing the internal structure of an electric double layer capacitor (electrochemical element) according to this embodiment, and FIG. 2 is an exploded perspective view showing the structure of an electrode sheet assembly according to this embodiment. FIG. 3 is an exploded perspective view showing the structure of the laminate.

  As shown in FIG. 1, an electric double layer capacitor 10 (hereinafter also simply referred to as “capacitor 10”) includes a casing 1 and an electrode sheet assembly EA accommodated in the casing 1 together with an electrolytic solution. Configured.

  The casing 1 is composed of a rectangular cylindrical cylinder 11 and a lid body 12 attached to the upper and lower openings of the cylindrical body 11. And this casing 1 comes to be sealed by attaching the edge part of the cover body 12 to the edge part of the up-and-down opening part of the cylinder 11 by a bending process, a crimping process, or welding (fusion | fusion). ing.

  As shown in FIG. 2, the electrode sheet assembly EA includes a laminated body LA formed by laminating a plurality of electrode sheets 2, and two upper and lower L-shaped lead plates that sandwich the laminated body LA in the laminating direction ( Current collector plates) 3 and 3.

  As shown in FIG. 3, the laminate LA includes a plurality of electrode sheets 2 for storing electric charge, separators 4 provided between the electrode sheets 2, and a predetermined electrode sheet 2 or between the electrode sheets 2 and L. And a shim 5 provided between the lead plate 3 (see FIG. 1).

  The electrode sheet 2 is composed of a substantially rectangular current collecting foil 2a and electrode layers 2b formed on both surfaces of the current collecting foil 2a. The current collector foil 2a is formed of a conductive material such as an aluminum foil. The electrode layer 2b is mainly composed of activated carbon, and is formed in a substantially rectangular shape over substantially the entire surface excluding one side portion of the current collector foil 2a. One side portion of the current collector foil 2a where the electrode layer 2b is not formed serves as a lead portion 2c as an outlet for the electric charge stored in each electrode layer 2b.

  Further, a through hole 2d for electrolyte injection is formed at the center of the electrode sheet 2, and two long holes 2e contributing to weight reduction and electrolyte penetration are inserted into the lead 2c and bolts inserted. Two common circular holes 2f are formed so as to pass therethrough. Further, a notch 2g that mainly contributes to weight reduction is formed at the edge of the lead portion 2c of the electrode sheet 2 (specifically, between the four holes 2e and 2f). The plurality of electrode sheets 2 formed in this way are configured such that a positive charge storage and a negative charge storage are alternately stacked, and a positive charge storage electrode sheet 2. The lead portions 2c are aligned in a predetermined direction, and the lead portions 2c of the electrode sheet 2 storing negative charges are aligned in a direction opposite to the predetermined direction (different direction).

  The separator 4 is an insulating member formed in a substantially rectangular sheet shape, and insulates adjacent electrode sheets 2 having different polarities (a pair of electrode sheets 2 in which the lead portions 2c face each other in opposite directions). The separator 4 is formed to have a size that slightly protrudes from the peripheral edge of the electrode layer 2b of the electrode sheet 2 and that does not block the long hole 2e and the hole 2f, and the center thereof. A through hole 4d for electrolyte injection is formed in the part with a size smaller than the through hole 2d of the electrode sheet 2 (see FIG. 1).

  The shim 5 is a substantially strip-shaped member having electrical conductivity, and the corners thereof are appropriately chamfered into an R shape, and have notches 5g corresponding to the notches 2g of the electrode sheet 2 described above on both side edges. It is formed in a simple shape. The shim 5 is appropriately formed with two long holes 5e and two holes 5f corresponding to the long holes 2e and the holes 2f of the electrode sheet 2, respectively. The shim 5 is formed between the lead portions 2c of the adjacent electrode sheets 2 having the same polarity (a pair of electrode sheets 2 in which the lead portions 2c face each other in the same direction) or between the lead portions 2c from the end. It is arranged between the lead portion 2c and the L-shaped lead plate 3 (see FIG. 1). Here, since the distance between the electrode sheet 2 located second from the end and the L-shaped lead plate 3 is shorter than the distance between the lead portions 2c of the electrode sheet 2 having the same polarity, Two types of shims 5 (hereinafter also referred to as “first shims 5A (end portion shims)” and “second shims 5B”) are provided. In the laminated body LA, a space is formed by the long hole 2e of the electrode sheet 2 and the long hole 5e of the shim 5 communicating with each other. This space can be made to function as a buffer unit responsible for an increase in volume when gas is generated due to decomposition of the electrolytic solution or the like.

  As shown in FIG. 2, the L-shaped lead plate 3 is a conductive member, and a current collecting wall 31 that collects current from the electrode sheet 2 with the same polarity, and an end of the laminated electrode sheet 2. The holding wall 32 that holds the electrode sheet 2 is formed in a substantially L shape.

  The current collecting wall 31 is formed in a square plate shape having a smaller width than the electrode sheet 2, and a predetermined bead portion 31 a extending in the stacking direction of the electrode sheet 2 is convex toward the electrode sheet 2 side at the center thereof. In addition, a bent portion 31b that is bent in a substantially L shape toward the electrode sheet 2 side and the outside is formed on the side edge portion. The bead portion 31a and the bent portion 31b formed on the current collecting wall 31 serve to improve the rigidity of the planar current collecting wall 31, and each of the notch portions 2g of the electrode sheet 2 and the shim 5 described above. By engaging with 5g, each electrode sheet 2 and each shim 5 are also positioned in the surface direction (specifically, the longitudinal direction of the shim 5). And the current collection wall 31 formed in this way has the edge part 31c of the bending part 31b joined to each electrode sheet 2 and each shim 5 of the same polarity by welding, Thereby, from each electrode sheet 2 It collects the current that flows.

  In this embodiment, the edge part 31c of the bending part 31b is welded to each electrode sheet 2 and each shim 5 of the same polarity using laser welding. The laser to be irradiated is generated such that the energy density indicating the energy of the laser per unit area of the irradiation range can be adjusted, and the edge 31c of the bent portion 31b (see FIGS. 2 and 6), specifically, the bent portion 31b. And the boundary portion K (see FIG. 6) between each electrode sheet 2 and each shim 5 is irradiated. A YAG laser can be preferably used as the type of laser. Since the YAG laser can be transmitted by an optical fiber, it is easy to control the output and reduce the irradiation area on the processed surface, and perform good welding even when the electrode sheet assembly EA is small. Is preferable.

The holding wall 32 is formed in a square plate shape having a larger area than the electrode sheet 2, and a terminal connection plug (current extraction portion) for taking out the current collected by the current collecting wall 31 from the outside at the center thereof. 6 and holes 32f for inserting bolts are formed at the four corners. In this embodiment, since the bolt is inserted so as to straddle the holding walls 32, 32 of the two L-shaped lead plates 3, 3, the material of the bolt is made insulative or made of metal. It is necessary to prevent a short circuit between the L-shaped lead plates 3 and 3 by insulating the portion of the bolt that contacts one holding wall 32. In addition, a shaft may be used instead of the bolt, and the end of the shaft arranged so as to straddle the holding walls 32 and 32 is caulked from the holding walls 32 and 32.
Is desirable.

  Further, as shown in FIG. 1, the terminal connection plug 6 is fixed to the holding wall 32 by screwing the male plug 61 and the female plug 62 with the holding wall 32 interposed therebetween. It has a structure. Therefore, in order to cope with this, the holding wall 32 has a mounting hole 32a for inserting the male screw portion 61a of the male plug 61, an end surface of the male plug 61 on the flange portion 61b side, and an electrode sheet of the holding wall 32. A step-shaped attachment portion 32b is formed to make the two end surfaces flush.

  In addition, the surface of the holding wall 32 on the side of the electrode sheet 2 (the surface on which the terminal connection plug 6 is attached) is subjected to insulation treatment with the insulating film 32c. In this embodiment, since the holding wall 32 and the electrode sheet 2 adjacent to the holding wall 32 have the same polarity, it is not necessary to insulate the holding wall 32 and the electrode sheet 2, and the insulating film 32c is omitted at least in this portion. Also good. However, since the insulating film 32c also has a function of preventing the electrode sheet 2 from being damaged by the surface shape of the holding wall 32 (small irregularities around the terminal connection plug 6) in addition to the insulating function, It is desirable to provide it like a form. The insulating film 32c is provided with a hole 32d corresponding to the electrolyte solution injection / discharge hole 61c formed in the male plug 61 of the terminal connection plug 6.

  Further, a step 32e serving as a substitute for the shim 5 is formed at the end of the holding wall 32 on the side of the current collecting wall 31 (one shoulder portion of the electrode sheet assembly EA). As shown in FIG. 4, the stepped portion 32e has a thickness obtained by adding the thickness t1 of the insulating film 32c and the thickness t2 of the electrode layer 2b. Here, when such a stepped portion 32e is not formed, the thickness of the electrode layer 2b is between the holding wall 32 and the lead portion 2c of the electrode sheet 2 adjacent thereto as shown in FIG. Although it is necessary to newly provide a conductive shim (third shim 5C) or a conductive shim having a thickness obtained by adding the thickness of the insulating film 32c and the thickness of the electrode layer 2b (not shown). Then, by providing the step portion 32e, it is possible to eliminate the shim (third shim 5C) and reduce the number of parts. Moreover, since there are only two places where the third shim 5C is disposed on the electrode sheet assembly EA, the provision of the stepped portion 32e has a great significance in reducing the number of parts.

  Incidentally, the second shim 5B disposed between the lead portions 2c of the electrode sheet 2 has four electrode layers 2b (thickness t2 × 4) and two thicknesses as shown in FIG. The third shim 5C has a thickness obtained by adding the separator 4 (thickness t3 × 2) and one current collector foil 2a (thickness t4 × 1) and is larger than the space of the stepped portion 32e. In this case, an unnecessary space is formed in the electrode sheet assembly EA, which is not preferable.

  As shown in FIG. 6, the first shim 5A is provided on the other shoulder portion of the electrode sheet assembly EA as described above. In the present embodiment, the first shim 5A is an insulating member. It is formed. That is, since the first shim 5A adjacent to the tip 31d of the current collecting wall 31 of the L-shaped lead plate 3 is an insulating member, the holding wall 32 of the L-shaped lead plate 3 on the side of the different polarity disposed adjacent thereto is arranged. Thus, the insulation state is maintained satisfactorily. As the insulating member, ceramics or flame retardant resin can be used. Ceramics are preferable in that they are not melted by the laser welding.

  Incidentally, as shown in FIG. 6, the first shim 5A has a thickness of three electrode layers 2b (thickness t2 × 3), one separator 4 (thickness t3 × 1), and one The thickness is obtained by adding the current collector foil 2a (thickness t4 × 1), and is thinner than the second shim 5B. Such a first shim 5A is provided at only two locations on the electrode sheet assembly EA, but the different polar charges are provided at the locations where the different L-shaped lead plates 3 are arranged close to each other as described above. Since it has a function of maintaining a good insulating state so as not to interfere with each other, it contributes to an improvement in the yield of the electrode sheet assembly EA. Further, the current flowing from the electrode sheet 2 adjacent to the first shim 5A does not go to the first shim 5A side, but flows only to the opposite side (the side from which the current is extracted). Electricity can be performed better.

Next, a method for manufacturing the capacitor 10 according to the present embodiment will be described.
As shown in FIG. 3, first, the electrode sheets 2 and the separators 4 are alternately laminated so that the directions of the lead portions 2c of the adjacent electrode sheets 2 are alternately reversed. Moreover, when laminating | stacking in this way, the shim 5 is arrange | positioned suitably with respect to the lead part 2c of each electrode sheet 2. As shown in FIG.

  Then, as shown in FIG. 2, the laminated body LA is sandwiched in the stacking direction by the L-shaped lead plate 3 to which the terminal connection plug 6 and the insulating film 32c (see FIG. 1) are previously attached. At this time, the bead portion 31a and the bent portion 31b of the L-shaped lead plate 3 are appropriately engaged with the notches 2g and 5g of the electrode sheet 2 and the shim 5, and the surface of the current collecting wall 31 of the L-shaped lead plate 3 Thus, by aligning the electrode sheets 2 and the shims 5, the bolt insertion holes 32 f, 2 f, 5 f of the components 3, 2, 5 are aligned coaxially. Thereafter, a bolt (not shown) is inserted into the holes 32f, 2f, 5f, and the tip of the inserted bolt is screwed into a nut (not shown) to hold the L-shaped lead plate 3 as shown in FIG. The laminated body LA is held by the wall 32. Here, since the holding wall 32 is formed larger than the area of the electrode sheet 2 as described above, the entire surface of each electrode sheet 2 is uniformly pressed by the large holding wall 32.

  Here, for example, when the thickness of the electrode layer 2b is Amm and the thickness of the insulating film 32c is Bmm, the step of the stepped portion 32e is (A + B) mm ((A + B) = 0.1-1. Therefore, it is difficult to mold the corresponding conductive shim (the third shim 5C (see FIG. 5)), and the step 32e is formed instead of the conductive shim as described above. This is very effective in production.

  As described above, after the laminated body LA is held with an appropriate pressure, the side edge portion (bent portion 31b) of the current collecting wall 31 of the L-shaped lead plate 3 is welded to each electrode sheet 2 and each shim 5. Thus, the manufacture of the electrode sheet assembly EA is completed. Specifically, a laser beam is irradiated to the boundary portion K (see FIG. 6) between the bent portion 31b, each electrode sheet 2 and each shim 5, and welding is performed by moving the irradiation point along the boundary portion K. I do. The irradiation point is moved, for example, from the holding wall 32 side of the current collecting wall 31 toward the tip 31d of the current collecting wall 31. Preferably, the movement speed of the irradiation point is varied so that the latter half speed is increased.

  As shown in FIG. 6, the end point of laser welding is point X1 because the first lead portion 2 c from the end (holding wall 32) needs to be welded to the tip portion 31 d of the current collecting wall 31. However, it is difficult to finish the laser beam irradiation accurately and accurately, and in the miniaturized electrode sheet assembly EA, it is further difficult to finish it with high accuracy. Therefore, the intention to end laser welding at the point X1 may end beyond the point X2 applied to the first shim 5A. In this case, if the first shim 5A is made of a conductive member, there is a possibility that electric charges interfere with the holding wall 32 having a different polarity via the first shim 5A, which may result in a defective product. . In contrast, in the present embodiment, since the first shim 5A is made of an insulating member such as ceramics, as described above, even when laser welding is completed at a position beyond the point X2, the first shim 5A is In this way, there is no interference between the non-polar holding wall 32 and the electric charge, so that the product yield can be improved.

  Thereafter, as shown in FIG. 1, the electrode sheet assembly EA is accommodated in the casing 1, and then an electrolytic solution is injected from the hole 61 c of the terminal connection plug 6, whereby the electrode layer 2 b of each electrode sheet 2. Each separator 4 is impregnated with an electrolytic solution. Finally, the hole 61c of the terminal connection plug 6 is sealed with a plug (not shown), whereby the manufacture of the capacitor 10 is completed.

According to the above, the following effects can be obtained in the present embodiment.
The stacked electrode sheets 2 are sandwiched in the stacking direction by the holding walls 32 of the two substantially L-shaped current collecting plates 3, and each electrode sheet 2 is held in a good pressure state. For this reason, the current collector foil 2a and the electrode layer 2b can be brought into close contact with each other to reduce the electric resistance, and the capacitance can be increased.

Further, since the step portion 32e serving as a substitute for the shim (third shim 5C) is formed at the end of the holding wall 32 on the current collecting wall 31 side in the L-shaped lead plate 3, the shim (third shim 5C) The number of parts can be reduced by eliminating the above. If such a stepped portion 32e is not formed, it is necessary to provide a shim (third shim 5C) between the holding wall 32 and the electrode sheet 2 adjacent thereto, and the types of shims 5 increase. In addition to being complicated, there is a risk of incorrect assembly.
On the other hand, since the shim (the third shim 5C) can be eliminated by the simple configuration of forming the stepped portion 32e, the number of the shim 5 is reduced correspondingly, and the assembly can be easily performed. Prevention becomes possible.

  Of the plurality of shims 5 for holding the electrode sheet 2 in a predetermined position, the first shim 5A for the end adjacent to the tip 3d of the current collecting wall 31 in the L-shaped lead plate 3 is an insulating member. Therefore, interference between charges of different polarities can be effectively prevented.

  Further, the surface of the holding wall 32 of the L-shaped lead plate 3 on the side of the electrode sheet 2 is subjected to insulation treatment by the insulating film 32c, so that the first shim 5A for the end portion is formed of an insulating member. Due to this synergistic effect, interference between different polar charges can be more effectively prevented. In the above-described embodiment, the holding wall 32 and the electrode sheet 2 adjacent to the holding wall 32 have the same polarity. However, even in a configuration in which the holding wall 32 has a different polarity, the holding wall 32 is adjacent to the holding wall 32 by the insulating film 32c. The electrode sheet 2 can be well insulated.

In addition, this invention is implemented in various forms, without being limited to the said embodiment.
In the present embodiment, the first shim 5A is formed of an insulating member, but the second shim 5B may also be formed of an insulating member. In this case, since the current flowing from the electrode sheet 2 adjacent to the second shim 5B does not go to the second shim 5B side, it flows toward only the opposite side (side from which the current is extracted). Current collection can be performed better.

  In the present embodiment, the electric double layer capacitor 10 is employed as the electrochemical element, but the present invention is not limited to this, and a battery such as a lithium ion secondary battery may be employed.

It is sectional drawing which shows the internal structure of the electric double layer capacitor which concerns on this embodiment. It is a disassembled perspective view which shows the structure of the electrode sheet assembly which concerns on this embodiment. It is a disassembled perspective view which shows the structure of a laminated body. It is an expanded sectional view which shows the level | step-difference part which is the principal part of the electrode sheet assembly which concerns on this embodiment. It is an expanded sectional view which shows the example which used the shim instead of the level | step-difference part. It is an expanded fragmentary sectional view which shows the part using the shim which consists of an insulating member which is the principal part of the electrode sheet assembly which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Casing 2 Electrode sheet 2a Current collection foil 2b Electrode layer 2c Lead part 3 L-shaped lead plate (current collection plate)
31 Current collecting wall 32 Holding wall 32c Insulating film 32e Stepped part 4 Separator 5 Shim 5A First shim 5B Second shim 6 Terminal connection plug (current extraction part)
10 Electric double layer capacitor (electrochemical element)
EA electrode sheet assembly LA laminate

Claims (2)

A plurality of electrode sheets each having an electrode layer formed on a current collector foil; and a separator disposed between the electrode sheets; and an electrochemical element in which the electrode layer and the separator are impregnated with an electrolyte solution,
A current collecting wall that collects current from a part of the plurality of electrode sheets, and an electrode sheet at an end of the stacked electrode sheets are held, and the current collected by the current collecting walls is taken out to the outside And sandwiching the laminated electrode sheets in the laminating direction with two substantially L-shaped current collecting plates having a holding wall provided with a current extraction portion,
A plurality of shims for holding the electrode sheet in place;
An electrochemical element, wherein a step portion serving as a substitute for the shim is formed at an end of the holding wall of the current collecting plate on the side of the current collecting wall. A plurality of electrode sheets each having an electrode layer formed on a current collector foil; and a separator disposed between the electrode sheets; and an electrochemical element in which the electrode layer and the separator are impregnated with an electrolyte solution,
A current collecting wall that collects current from a part of the plurality of electrode sheets, and an electrode sheet at an end of the stacked electrode sheets are held, and the current collected by the current collecting walls is taken out to the outside And sandwiching the laminated electrode sheets in the laminating direction with two substantially L-shaped current collecting plates having a holding wall provided with a current extraction portion,
A plurality of shims for holding the electrode sheet in place;
A step portion serving as a substitute for the shim is formed at an end portion of the holding wall of the current collecting plate on the current collecting wall side, and the current collecting wall in the current collecting plate among the plurality of shims. The electrochemical element according to claim 1, wherein the shim for the end adjacent to the tip is formed of an insulating member.

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