JP2015144306A - electrochemical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochemical device capable of avoiding an increase in connection resistance between the top surface of a current collector film and the surface on one electrode side of a power storage element.SOLUTION: In an electrochemical device, the bottom surface 11a1 of a first recess 11a of a case 11 has an opening outline smaller than that of the undersurface of a first electrode sheet 13a of a power storage element 13, and a second recess 11b having a predetermined depth D11b is formed on the bottom surface 11a1. A power collector film 19 having a thickness T19 smaller than the depth of the second recess 11b is provided on the bottom surface 11b1 of the second recess 11b. Between the bottom surface 11a1 of the first recess 11a and the top surface of the power collector film 19, an adhesive material reservoir AR is formed having the depth corresponding to a dimension (=D11b-T19) obtained by subtracting the thickness T19 of the power collector film 19 from the depth D11b of the second recess 11b. A first conductive adhesive layer 20 is provided so as to be filled in the adhesive material reservoir AR.

Description

  The present invention relates to an electrochemical device enclosing a chargeable / dischargeable power storage element.

  For electronic devices such as mobile phones, laptop computers, video cameras, and digital cameras, surface mountable electrochemical devices such as electric double layer capacitors and lithium ion capacitors are used as power sources suitable for memory backup applications. It has been.

  This electrochemical device generally includes an insulating case having a concave portion, a conductive lid in which the concave portion of the case is closed in a watertight and airtight manner, a chargeable / dischargeable storage element and an electrolysis device enclosed in the concave portion closed by the lid. The liquid, the positive electrode terminal and the negative electrode terminal provided on the mounting surface of the case, the positive electrode wiring for electrically connecting the positive electrode terminal and the positive electrode side of the energy storage device, and the negative electrode terminal and the negative electrode side of the energy storage device are electrically connected. And negative electrode wiring for connection (see Patent Documents 1 and 2).

  In addition, in the structure in which the surface on one side of the storage element faces the bottom surface of the recess of the case and the surface on the other side faces the bottom surface of the lid, the current collector film is usually formed on the bottom surface of the recess of the case. The surface of the electricity storage element is electrically connected to the upper surface of the current collector film via a conductive adhesive layer, and the surface of the current collector is electrically connected to the lower surface of the lid via another conductive adhesive layer. The surface on the other pole side of the element is electrically connected (see Patent Document 2).

  Further, when one surface of the electricity storage element is electrically connected to the upper surface of the current collecting film via a conductive adhesive layer, and the other surface of the electricity storage element is connected to the lower surface of the lid via another conductive adhesive layer. When electrically connecting the surfaces on the pole side, that is, in the step of arranging the electricity storage element, the surface on the one electrode side of the electricity storage element is pressed against the uncured conductive adhesive applied to the upper surface of the current collector film. The conductive adhesive is cured, and before and after this, the other adhesive side surface is pressed against the uncured conductive adhesive applied to the lower surface of the lid to cure the conductive adhesive. Is used.

  By the way, the one electrode side surface of the electricity storage element is electrically connected to the upper surface of the current collecting film via a conductive adhesive layer, and the other electrode of the electricity storage element is connected to the lower surface of the lid via another conductive adhesive layer. In the structure in which the side surfaces are electrically connected, even if the same conductive adhesive is used for both connections, the connection resistance between the upper surface of the current collector film and the surface on one side of the storage element ( The conduction resistance) tends to be higher than the connection resistance (conduction resistance) between the lower surface of the lid and the surface on the other pole side of the storage element.

  More specifically, since the lid itself is made of a conductive material such as Kovar and is manufactured as a single component, it is easy to obtain smoothness on its lower surface. Therefore, if a certain degree of parallelism can be secured on both surfaces when the surface of the other electrode side of the storage element is pressed against the uncured conductive adhesive applied to the lower surface of the lid, the thickness of the conductive adhesive layer Even if the thickness is reduced, the substantial conduction area between the lower surface of the lid and the surface on the other pole side of the storage element does not change.

  On the other hand, although the current collector film is made of a conductive material such as aluminum, it is retrofitted to the bottom surface of the concave portion of the case by a technique such as thermal spraying, so that smoothness like the lower surface of the lid can be obtained on the upper surface. difficult. Therefore, even when a certain degree of parallelism can be secured on both surfaces when pressing the surface on one side of the storage element against the uncured conductive adhesive applied to the upper surface of the current collector film, the conductive adhesive layer When the thickness of the conductive film is reduced, a portion with a thickness of zero or a portion close to zero appears in the conductive adhesive layer, and the substantial conduction area between the upper surface of the current collector film and the surface on one side of the storage element is reduced. As a result, the connection resistance (conduction resistance) between the upper surface of the current collector film and the surface on the one pole side of the storage element increases.

  Such an increase in connection resistance (conduction resistance) leads to a decrease in charge / discharge characteristics based on an increase in internal resistance of the electrochemical device, and therefore it is desirable to avoid it from the viewpoint of realizing a large current.

JP 2009-278068 A JP 2006-222221 A

  An object of the present invention is to provide an electrochemical device capable of avoiding an increase in connection resistance (conduction resistance) between an upper surface of a current collecting film and a surface on one side of a power storage element.

  In order to achieve the above object, the present invention provides an insulating case having a first recess, a conductive lid that closes the first recess in a watertight and airtight manner, and a current collector film provided on the bottom of the first recess. And a chargeable / dischargeable power storage element enclosed in the first recess closed by the lid, and an electrolyte solution, and the top surface of the current collecting film has a first conductive adhesive layer interposed therebetween. In the electrochemical device in which the surface on one pole side is electrically connected, and the surface on the other pole side of the electricity storage element is electrically connected to the lower surface of the lid via a second conductive adhesive layer, On the bottom surface of the first recess, a second recess having an opening contour smaller than the contour of the surface on the one pole side of the power storage element and having a predetermined depth is formed. It has a thickness smaller than the depth of the second recess and is formed on the bottom surface of the second recess. And an adhesive having a depth corresponding to a dimension obtained by subtracting the thickness of the current collecting film from the depth of the second recessed part between the bottom surface of the first recessed portion and the upper surface of the current collecting film. A storage part is formed, and the first conductive adhesive layer is provided so as to be filled in the adhesive storage part.

  According to the present invention, the presence of the adhesive reservoir can ensure a sufficient thickness for the entire first conductive adhesive layer. A portion close to zero appears, that is, a substantial conduction area between the upper surface of the current collector film and the one pole side surface of the power storage element is prevented from decreasing, and one of the upper surface of the current collector film and one of the power storage elements is prevented. It is possible to reliably avoid an increase in connection resistance (conduction resistance) with the surface on the pole side.

  The above object and other objects, structural features, and operational effects of the present invention will become apparent from the following description and the accompanying drawings.

FIG. 1 is an external perspective view of an electrochemical device (first embodiment) to which the present invention is applied. FIG. 2 is an enlarged cross-sectional view taken along line S11-S11 of the electrochemical device shown in FIG. FIG. 3 is an enlarged top view of the case shown in FIG. 4 (A) and 4 (B) are partial enlarged views corresponding to FIG. 2, showing a specific mode of the first conductive adhesive layer shown in FIG. FIG. 5 is a cross-sectional view corresponding to FIG. 2 of an electrochemical device (second embodiment) to which the present invention is applied. FIG. 6 is a cross-sectional view corresponding to FIG. 2 of an electrochemical device (third embodiment) to which the present invention is applied. FIG. 7 is a cross-sectional view corresponding to FIG. 2 of an electrochemical device (fourth embodiment) to which the present invention is applied.

<< First Embodiment >>
1 to 3 show an electrochemical device (first embodiment) to which the present invention is applied. The electrochemical device 10 shown in the figure includes an insulating case 11, a conductive lid 12, a storage element 13, a positive electrode terminal 14, a negative electrode terminal 15, a positive electrode wiring 16, and a negative electrode wiring 17. The case 11 is provided with a positive electrode terminal 14, a negative electrode terminal 15, a positive electrode wiring 16, and a negative electrode wiring 17, as well as a coupling ring 18 and a current collecting film 19.

<Configuration of case 11>
The case 11 is formed of an insulating material such as alumina so as to form a rectangular parallelepiped shape having a predetermined length, width, and height, and its lower surface is used as a mounting surface. The case 11 has a first recess 11a having a rectangular opening contour and a predetermined depth. Furthermore, a second recessed portion 11b having a rectangular opening contour smaller than the lower surface contour of the first electrode sheet 13a, which is described later, and having a predetermined depth D11b is provided at substantially the center of the bottom surface 11a1 of the first recessed portion 11a. Is formed. Furthermore, at the four corners when the case 11 is viewed from above, cutouts 11c whose upper surface outline forms a substantially ¼ circle are formed in the vertical direction.

  The positive electrode terminal 14 is formed of a conductive material such as gold so as to form an L-shaped cross section extending from the center of the end surface in the length direction of the case 11 to the lower surface and having a predetermined width. The negative electrode terminal 15 is formed of a conductive material such as gold so as to form an L-shaped cross section extending from the center of the other end surface in the length direction of the case 11 to the lower surface, and has substantially the same width as the positive electrode terminal 14. Has been.

  Although not shown in the drawings, when the positive electrode terminal 14 and the negative electrode terminal 15 are not directly formed on the side surface and the lower surface of the case 11 due to the material of the case 11 or the like, the side surface is not obtained. Further, an adhesion auxiliary layer (for example, a film in which a tungsten film and a nickel film are arranged in order from the case 11 side) for increasing adhesion between the positive electrode terminal 14 and the negative electrode terminal 15 with respect to the lower surface is formed in advance on the side and lower surface terminals of the case 11. It is good to form in position.

  The positive electrode wiring 16 is formed inside the case 11 from a conductive material such as tungsten so as to reach the lower surface of the current collecting film 19 from the center of one end surface in the length direction of the case 11. Specifically, as shown in FIG. 3, the positive electrode wiring 16 includes a rectangular portion (no reference) having substantially the same width as the positive electrode terminal 14, and a total of three strip portions 16 a extending inward from the rectangular portion. And a total of three columnar portions 16b extending from the end of each band-shaped portion 16a toward the current collecting film 19. Further, the positions of the respective columnar portions 16 b are different on the bottom surface 11 b 1 of the second concave portion 11 b of the case 11. Furthermore, a portion of the rectangular portion exposed from one end surface in the length direction of the case 11 is electrically connected to a side surface portion of the positive electrode terminal 14, and the upper end of each columnar portion 16 b is the lower surface of the current collector film 19. Is electrically connected.

  Although not shown in the figure, due to the material of each columnar portion 16b of the positive electrode wiring 16 and the like, if sufficient conductivity is not obtained at the upper end of each columnar portion 16b and the lower surface of the current collector film 19, A conductive auxiliary layer (for example, a nickel film and a gold film are arranged in order from the upper end side of each columnar portion 16b) for increasing the conductivity between the upper end of each columnar portion 16b and the lower surface of the current collector film 19 is previously formed in each columnar shape. It is good to form in the upper end of the part 16b.

  A part of the negative electrode wiring 17 is formed inside the case 11 from a conductive material such as tungsten to reach the upper surface of the case 11 from the center of the other end surface in the length direction of the case 11, and the other part is the case 11. Are formed on the side surface and the upper surface. Specifically, as shown in FIG. 3, the negative electrode wiring 17 has a rectangular portion (not indicated) having substantially the same width as the negative electrode terminal 15 and positioned in the case 11, and a case extending outward from the rectangular portion. 11, a total of two strips 17a located in the inner surface of the two notches 11c of the case 11 continuously with each strip 17a, and each strip 17b. It has a total of two fan-shaped parts 17c located on the upper surface of the case 11 continuously. Further, the portion of the rectangular portion exposed from the other end surface in the length direction of the case 11 is electrically connected to the side surface portion of the negative electrode terminal 15, and the upper surface of each fan-shaped portion 17 c is electrically connected to the lower surface of the coupling ring 18. It is connected to the.

  The coupling ring 18 is formed of a conductive material such as Kovar (iron-nickel-cobalt alloy) so as to have a rectangular upper surface profile slightly smaller than the upper surface profile of the case 11. The coupling ring 18 has an inner hole 18 a having a rectangular opening contour, and the opening contour of the inner hole 18 a substantially coincides with the opening contour of the first recess 11 a of the case 11. Since this coupling ring 18 is coupled to the upper surface of the case 11 via a bonding material so that the inner hole 18a substantially coincides with the first recess 11a, the inner hole 18a is used as the upper part of the first recess 11a. (Hereinafter referred to as the first recess 11a of the case 11 including the inner hole 18a of the coupling ring 18).

  Although not shown in the drawing, sufficient bonding force can be obtained even if the bonding ring 18 is directly bonded to the upper surface of the case 11 using a bonding material, for example, a brazing material such as a gold-copper alloy, due to the material of the case 11 or the like. Is not obtained, a coupling auxiliary layer (for example, a tungsten film and a nickel film are sequentially arranged from the upper surface side of the case 11 in order) to increase the bonding force of the coupling ring 18 to the upper surface is previously provided in the case 11. It is good to form in the ring coupling position of the upper surface of the. Further, when the coupling ring 18 is made of a material having low corrosion resistance to the electrolytic solution, a corrosion-resistant film for improving the corrosion resistance to the electrolytic solution (for example, a nickel film and a gold film arranged in order from the surface side of the coupling ring 18, It is preferable that the gold film is replaced with another metal film such as platinum, silver, or palladium on the surface of the coupling ring 18 (at least the upper and lower surfaces and the inner surface of the inner hole 18a).

  The current collecting film 19 is formed on the bottom surface 11b1 of the second recess 11b of the case 11 from a conductive material such as aluminum, and the rectangular upper surface contour substantially coincides with the opening contour of the second recess 11b. . The current collecting film 19 is retrofitted to the bottom surface 11b1 of the second recess 11b of the case 11. The formation of the current collecting film 19 depends on the material of the current collecting film 19, the material of the case 11, etc. In addition to the forming method, a thin film forming method such as CVD can be used. Further, the thickness T19 of the current collecting film 19 is smaller than the depth D11b of the second recess 11b of the case 11. Therefore, a depth corresponding to the dimension obtained by subtracting the thickness T19 of the current collector film 19 from the depth D11b of the second recess 11b is provided between the bottom surface 11a1 of the first recess 11a and the upper surface of the current collector film 19. An adhesive reservoir AR is formed. Furthermore, from the viewpoint of suppressing an increase in the height of the electrochemical device 10, the preferable depth of the adhesive reservoir AR is 5 to 100 μm, although it depends on the type of conductive adhesive described later. For example, when the depth D11b of the second recess 11b is 50 μm and the thickness T19 of the current collector film 19 is 30 μm, the depth of the adhesive reservoir AR is 20 μm.

  Although not shown, the upper surface contour of the current collector film 19 may be slightly smaller than the opening contour of the second recess 11b. Further, the upper surface contour of the current collecting film 19 is not limited to a rectangular shape, and may be a shape with rounded corners, an ellipse, or a shape close to an ellipse.

<Configuration of Lid 12 and Bonding Method>
The lid 12 is made of a conductive material such as Kovar (iron-nickel-cobalt alloy), preferably a clad material having a nickel film on the upper and lower surfaces of the Kovar base material, a clad material having a nickel film on the lower surface of the Kovar base material, The nickel film is formed of a clad material obtained by changing the nickel film into a metal film such as platinum, silver, gold, or palladium so as to have a rectangular upper surface profile that substantially matches the upper surface profile of the coupling ring 18. In the drawing, the center portion of the lid 12 bulged in a rectangular shape is shown as the lid 12, but a flat plate shape may be used as the lid 12.

  The lid 12 is coupled so that the outer peripheral portion of the lower surface thereof is electrically connected to the upper surface of the coupling ring 18 after the storage element 13 is disposed inside the first recess 11a of the case 11, and the coupling causes the case 11 to be electrically connected. The first recess 11a is closed in a watertight and airtight manner. Incidentally, for bonding the lid 12 to the coupling ring 18, a direct bonding method such as seam welding or laser welding can be used, or an indirect bonding method with a conductive bonding material can be used.

<Configuration and Arrangement Method of Storage Element 13>
The power storage element 13 includes a rectangular first electrode sheet 13a, a rectangular second electrode sheet 13b, and a rectangular separate sheet 13c interposed between the electrode sheets 13a and 13b. Yes.

  The lower surface contour of the first electrode sheet 13a is smaller than the upper surface contour of the first recess 11a of the case 11 and larger than the opening contour of the second recess 11b. The upper surface contour of the second electrode sheet 13b is smaller than the upper surface contour of the first recess 11a of the case 11, and substantially coincides with the lower surface contour of the first electrode sheet 13a. The upper surface contour of the separate sheet 13c is slightly smaller than the upper surface contour of the first recess 11a of the case 11, and slightly larger than the lower surface contour of the first electrode sheet 13a and the upper surface contour of the second electrode sheet 13b.

  The first electrode sheet 13a and the second electrode sheet 13b are made of an active material such as activated carbon, graphite, or PAS (polyacenic semiconductor), and the separate sheet 13c is mainly made of glass fiber, cellulose fiber, plastic fiber, or the like. It consists of a porous sheet. Incidentally, the materials of the first electrode sheet 13a and the second electrode sheet 13b may be the same or different depending on the type of the electrochemical device 10, for example, the first electrode sheet when the electrochemical device 10 is an electric double layer capacitor. The material of 13a and the 2nd electrode sheet 13b is the same, and when the electrochemical device 10 is a lithium ion capacitor, the material of the 1st electrode sheet 13a and the 2nd electrode sheet 13b differs.

  The electric storage element 13 is enclosed inside the first recess 11 a closed by the lid 12 together with an electrolyte solution (not shown). Incidentally, the composition of the electrolytic solution varies depending on the type of the electrochemical device 10. For example, when the electrochemical device 10 is an electric double layer capacitor, an electrolytic solution in which an electrolyte salt is dissolved in a solvent is used. In the case of a capacitor, an electrolytic solution in which a lithium salt is dissolved in a solvent is used.

  When the polarity at the time of use is not fixed to the 1st electrode sheet 13a and the 2nd electrode sheet 13b which comprise electrical storage element 13, (for example, when electrochemical device 10 is an electric double layer capacitor), ie, 1st electrode sheet 13a Can be selectively used as one of the positive electrode and the negative electrode, and the second electrode sheet 13b can be selectively used as the other of the positive electrode and the negative electrode, the storage element 13 is placed inside the first recess 11a of the case 11. There is no need to worry about the order of insertion when placing.

  On the other hand, when the polarity at the time of use is predetermined for the first electrode sheet 13a and the second electrode sheet 13b constituting the energy storage device 13 (for example, when the electrochemical device 10 is a lithium ion capacitor), Pay attention to the insertion order when the storage element 13 is arranged inside the one recess 11a. For example, when the polarity of the first electrode sheet 13 a is set to the positive electrode and the polarity of the second electrode sheet 13 b is set to the negative electrode, the first electrode sheet 13 a on the positive electrode side is the upper surface of the current collector film 19. And the second electrode sheet 13b on the negative electrode side faces the lower surface of the lid 12.

  As can be seen from FIG. 2, the lower surface of the first electrode sheet 13 a of the electricity storage element 13 is formed on the current collector film 19 via the first conductive adhesive layer 20 provided so as to be filled in the adhesive reservoir AR. It is electrically connected to the top surface. On the other hand, the upper surface of the second electrode sheet 13 b of the electricity storage element 13 is electrically connected to the lower surface of the lid 12 through a second conductive adhesive layer 21 provided on the lower surface of the lid 12. The first conductive adhesive layer 20 and the second conductive adhesive layer 21 are cured products of a conductive adhesive, and the conductive adhesive preferably includes a thermosetting adhesive containing conductive particles, for example, Epoxy adhesives containing carbon particles (carbon black), graphite particles (graphite particles), and the like can be used.

  Here, with respect to the method of disposing the power storage element 13, (1) the case where the first electrode sheet 13a, the second electrode sheet 13b, and the separate sheet 13c are not manufactured as an integral object, and (2) the first electrode sheet 13a The case where the second electrode sheet 13b and the separate sheet 13c are manufactured as an integrated body will be described as an example. Incidentally, the injection of the electrolytic solution is performed at an appropriate timing before the lid 12 is coupled to the coupling ring 18.

  In the case of (1), the adhesive reservoir AR of the case 11 is filled with a predetermined amount of the conductive adhesive for the first conductive adhesive layer 20, and then the first electrode sheet is filled in the conductive adhesive. The lower surface of 13a is relatively pressed against and brought into close contact, and then the first electrode sheet 13a is dried and the conductive adhesive is cured. The position of the first electrode sheet 13a when the lower surface of the first electrode sheet 13a is pressed against the conductive adhesive filled in the adhesive reservoir AR is as shown by a two-dot chain line in FIG. The outer peripheral portion of the lower surface of the sheet 13a faces the bottom surface 11a1 of the first recess 11a. And the separate sheet | seat 13c is mounted in the upper surface of the 1st electrode sheet 13a, and electrolyte solution is inject | poured. Before and after this, the same conductive adhesive for the second conductive adhesive layer 21 as described above was applied to the lower surface of the lid 12 with a predetermined thickness, and then the second electrode sheet 13b was applied to the conductive adhesive. The upper surface is relatively pressed and brought into close contact, and then the second electrode sheet 13b is dried and the conductive adhesive is cured. Then, the outer peripheral portion of the lower surface of the lid 12 is overlaid on the upper surface of the coupling ring 18, and at the same time, the lower surface of the second electrode sheet 13b is overlaid on the upper surface of the separate sheet 13c. Then, the lid 12 is coupled to the coupling ring 18.

  In the case of (2), the adhesive storage part AR of the case 11 is filled with a predetermined amount of the conductive adhesive for the first conductive adhesive layer 20, and then integrated with the conductive adhesive. The lower surface of the first electrode sheet 13a of the (storage element 13) is relatively pressed against and brought into close contact. Then, the same conductive adhesive for the second conductive adhesive layer 21 as described above is applied to the lower surface of the lid 12 with a predetermined thickness, and then the second piece of the integrated object (electric storage element 13) is applied to the conductive adhesive. The upper surface of the electrode sheet 13b is relatively pressed and brought into close contact. Each conductive adhesive is cured individually or collectively (simultaneously). Then, the lid 12 is coupled to the coupling ring 18.

  In any of the arrangement methods, in the “step of filling a predetermined amount of the conductive adhesive for the first conductive adhesive layer 20 in the adhesive reservoir AR of the case 11” The adhesive reservoir AR is filled with a slightly larger amount of the conductive adhesive than the volume of the agent reservoir AR.

  In the “step of relatively pressing the lower surface of the first electrode sheet 13a”, when the outer peripheral portion of the lower surface of the first electrode sheet 13a is pressed so as to contact the bottom surface 11a1 of the first recess 11a, FIG. As shown in A), the surplus conductive adhesive SM protrudes outside the lower surface of the first electrode sheet 13a (on the bottom surface 11a1 of the first recess 11a) and is cured as it is. That is, in this case, the outer peripheral portion of the lower surface of the first electrode sheet 13a is in direct contact with the bottom surface 11a1 of the first recess 11a, and the region excluding the outer peripheral portion of the lower surface of the first electrode sheet 13a is the first. It adheres to the upper surface of the conductive adhesive layer 20. The amount of excess conductive adhesive SM protruding outside the lower surface of the first electrode sheet 13a depends on the amount of conductive adhesive filled in the adhesive reservoir AR, but the amount of protrusion is shown in FIG. Even if it is less or more than the mode shown in FIG. 5, there is no change in that the lower surface of the first electrode sheet 13a is in close contact with the upper surface of the first conductive adhesive layer 20 with a sufficient area for electrical connection. .

  Further, in the “step of relatively pressing the lower surface of the first electrode sheet 13a”, when the outer peripheral portion of the lower surface of the first electrode sheet 13a is pressed so as not to contact the bottom surface 11a1 of the first recess 11a, As shown in FIG. 4B, the surplus conductive adhesive SM protrudes under the outer peripheral portion of the lower surface of the first electrode sheet 13a and is cured as it is. That is, in this case, the outer peripheral portion of the lower surface of the first electrode sheet 13a is in contact with a part of the first conductive adhesive layer 20 that protrudes from the adhesive reservoir AR on the bottom surface 11a1 of the first recess 11a. A substantially entire area of the lower surface of the first electrode sheet 13 a is in close contact with the upper surface of the first conductive adhesive layer 20. The amount of excess conductive adhesive SM protruding below the outer peripheral portion of the lower surface of the first electrode sheet 13a depends on the amount of conductive adhesive filled in the adhesive reservoir AR and the pressing force, but the amount of protrusion Is less than or greater than the mode shown in FIG. 4B, the lower surface of the first electrode sheet 13a is in close contact with the upper surface of the first conductive adhesive layer 20 with a sufficient area for electrical connection. There is no change.

<Effect obtained by electrochemical device 10 (first embodiment)>
According to the electrochemical device 10, the following (Effect 1) to (Effect 3) can be obtained.

  (Effect 1) The electrochemical device 10 has an opening outline smaller than the outline of the lower surface of the first electrode sheet 13a of the electricity storage element 13 on the bottom surface 11a1 of the first recess 11a of the case 11, and has a predetermined depth. A second recess 11b having a thickness D11b is formed, and the current collecting film 19 has a thickness T19 smaller than the depth of the second recess 11b and is provided on the bottom surface 11b1 of the second recess 11b. Between the bottom surface 11a1 of 11a and the upper surface of the current collector film 19, a depth corresponding to a dimension (= D11b-T19) obtained by subtracting the thickness T19 of the current collector film 19 from the depth D11b of the second recess 11b. An adhesive reservoir AR is formed, and the first conductive adhesive layer 20 is provided so as to be filled in the adhesive reservoir AR.

  That is, the presence of the adhesive reservoir AR can ensure a sufficient thickness (= D11b-T19) for the entire first conductive adhesive layer 20, so that the first conductive adhesive layer 20 has a conventional thickness. Is prevented from appearing, that is, a substantial conduction area between the upper surface of the current collector film 19 and the lower surface of the first electrode sheet 13a of the power storage element 13 is reduced. It is possible to reliably avoid an increase in connection resistance (conduction resistance) between the upper surface of the electrode film 19 and the lower surface of the first electrode sheet 13a of the power storage element 13.

  (Effect 2) The first conductive adhesive layer 20 is configured as shown in FIG. 4A, that is, the outer peripheral portion of the lower surface of the first electrode sheet 13a is in direct contact with the bottom surface 11a1 of the first recess 11a. For example, since the thickness (= D11b−T19) of the first conductive adhesive layer 20 can be defined by at least one of the depth D11b of the second recess 11b and the thickness T19 of the current collector film 19, the first conductive adhesive layer Management of the thickness of the layer 20 is easy.

  (Effect 3) The embodiment shown in FIG. 4B of the first conductive adhesive layer 20, that is, the outer peripheral portion of the lower surface of the first electrode sheet 13 a is the first from the adhesive reservoir AR in the first conductive adhesive layer 20. Since the contact area between the lower surface of the first electrode sheet 13a and the upper surface of the first conductive adhesive layer 20 can be increased by adopting an aspect in contact with a part protruding on the bottom surface 11a1 of the one recess 11a, The substantial conduction area between the upper surface and the lower surface of the first electrode sheet 13a of the storage element 13 is increased, and the increase in the conduction area causes the upper surface of the current collector film 19 and the lower surface of the first electrode sheet 13a of the storage element 13 to The connection resistance (conduction resistance) between them can be reduced.

<< Second Embodiment >>
FIG. 5 shows an electrochemical device (second embodiment) to which the present invention is applied. The electrochemical device shown in the figure is different from the electrochemical device 10 described in the first embodiment, with regard to the configuration of the case 11.
-Instead of forming the second recess 11b on the bottom surface 11a1 of the first recess 11a, the first recess 11
A rectangular frame-shaped spacer SP1 is arranged on the bottom surface 11a1 of a, and the second recess 11b is formed by the inner space of the spacer SP1. Other configurations of the case 11, the configuration and coupling method of the lid 12, and the configuration and arrangement method of the power storage element 13 are the same as those of the electrochemical device 10 described in the above “first embodiment”.

  The rectangular top surface contour of the spacer SP1 substantially coincides with the top surface contour of the bottom surface 11a1 of the first recess 11a, and the opening contour of the inner hole (without reference numeral) is the same as the opening contour of the second recess 11b shown in FIG. The thickness is the same as the depth D11b of the second recess 11b shown in FIG. In addition, the material of the spacer SP1 may be the same material as the case 11 or a material different from the case 11 as long as it is an insulating material. Further, the spacer SP1 may be disposed on the bottom surface 11a1 of the first recess 11a after the current collector film 19 is formed on the bottom surface 11a1 of the first recess 11a, or may be disposed on the bottom surface 11a1 of the first recess 11a. It may be arranged on the bottom surface 11a1 of the first recess 11a before forming. Furthermore, the spacer SP1 may be simply placed on the bottom surface 11a1 of the first recess 11a without being bonded, or fixed to the bottom surface 11a1 of the first recess 11a via a thermosetting adhesive such as an epoxy adhesive. You may do it.

<Effect obtained by electrochemical device (second embodiment)>
According to the electrochemical device, in addition to (Effect 1) to (Effect 3) described in <Effects obtained by the electrochemical device 10 (first embodiment)> of the << first embodiment >> (Effect 4) can be obtained.

  (Effect 4) Since it becomes unnecessary to form the 2nd recessed part 11b in case 11 itself, the structure of this case 11 can be simplified. In particular, when the case 11 is made of ceramics such as alumina, a process is required in which an appropriate number of non-perforated unfired ceramic sheets and perforated unfired ceramic sheets are stacked and then pressed and fired. The number of parts can be reduced to simplify the process, and the unit price of the case 11 can be reduced.

<< Third Embodiment >>
FIG. 6 shows an electrochemical device (third embodiment) to which the present invention is applied. The electrochemical device shown in the figure is different from the electrochemical device 10 described in the first embodiment, with regard to the configuration of the case 11.
-The depth of the 1st recessed part 11a is made shallow, and the rectangular-shaped opening outline substantially corresponded with the lower surface outline of the 1st electrode sheet 13a of the electrical storage element 13 between this 1st recessed part 11a and the 2nd recessed part 11b. And a point where the third recess 11d having a predetermined depth is formed. The outer peripheral portion of the lower surface of the first electrode sheet 13a of the electricity storage element 13 is fitted into the third recess 11d. . Other configurations of the case 11, the configuration and bonding method of the lid 12, and the configuration and arrangement method of the power storage element 13 are the same as those of the electrochemical device 10 described in the above “first embodiment”. Since the mode of the layer 20 is slightly different from the mode shown in FIG. 4A and the mode shown in FIG.

  Since the adhesive reservoir AR is filled with a slightly larger amount of conductive adhesive than the volume of the adhesive reservoir AR, the outer peripheral portion of the lower surface of the first electrode sheet 13a is the bottom surface 11d1 of the third recess 11d. When pressed so as to be in contact with the surface, the surplus conductive adhesive is outside the lower surface of the first electrode sheet 13a (on the bottom surface 11a1 of the first recess 11a), as in the embodiment shown in FIG. It sticks out and hardens as it is. Moreover, when it presses so that the outer peripheral part of the lower surface of the 1st electrode sheet 13a may not contact the bottom face 11d1 of the 3rd recessed part 11d, as with the aspect shown to FIG. 4 (B), excess electroconductive adhesion The agent protrudes under the outer peripheral portion of the lower surface of the first electrode sheet 13a and is cured as it is.

  Since the third recess 11d serves to position the first electrode sheet 13a of the power storage element 13, the depth thereof is the first regardless of the aspect of the first conductive adhesive layer 20 described above. What is necessary is just the minimum value which the outer peripheral part of the lower surface of the electrode sheet 13a fits and can play the said role.

<Effects obtained by electrochemical device (third embodiment)>
According to the electrochemical device, in addition to (Effect 1) to (Effect 3) described in <Effects obtained by the electrochemical device 10 (first embodiment)> of the << first embodiment >> (Effect 5) can be obtained.

  (Effect 5) Since the outer peripheral portion of the lower surface of the first electrode sheet 13a of the electricity storage element 13 is fitted and disposed in the third recess 11d formed between the first recess 11a and the second recess 11b, When the lower surface of the first electrode sheet 13a of the power storage element 13 is pressed against the conductive adhesive filled in the adhesive reservoir AR, the position of the first electrode sheet 13a can be easily determined. Moreover, since the first electrode sheet 13a of the electricity storage element 13 is held by the third recess 11d, even when surface mounting the electrochemical device or when external force such as vibration is applied to the electrochemical device after surface mounting, By cooperating with the first conductive adhesive 20, it is possible to prevent the positional displacement of the first electrode sheet 13 a and, consequently, the storage element 13.

<< 4th Embodiment >>
FIG. 7 shows an electrochemical device (fourth embodiment) to which the present invention is applied. The electrochemical device shown in the figure is different from the electrochemical device described in the << third embodiment >>
The second recess 11b is formed on the bottom surface 11a1 of the first recess 11a, and the third recess 11d is not formed between the first recess 11a and the second recess 11b, but the bottom surface 11a1 of the first recess 11a1.
A rectangular frame-shaped spacer SP2 is disposed on the inner surface of the spacer SP2 to form a second concave portion 11b. A step formed on the upper portion of the inner hole (not indicated) of the spacer SP2. The third feature is that a recess 11d is formed. Other configurations of the case 11, the configuration and bonding method of the lid 12, and the configuration and arrangement method of the power storage element 13 are the same as those of the electrochemical device described in the above “third embodiment”.

  The rectangular top surface contour of the spacer SP2 substantially coincides with the top surface contour of the bottom surface 11a1 of the first recess 11a, and the opening contour of the inner hole (no symbol) is the same as the opening contour of the second recess 11b shown in FIG. The thickness is the same as the depth D11b of the second recess 11b shown in FIG. In addition, a step having an L-shaped cross section is provided on the upper portion of the inner hole of the spacer SP2 (boundary edge between the upper surface and the inner hole), and the step substantially matches the lower surface contour of the first electrode sheet 13a of the storage element 13. A third recess 11d having a rectangular opening contour and a predetermined depth is formed. Furthermore, the material of the spacer SP2 may be the same material as the case 11 or a material different from the case 11 as long as it is an insulating material. Furthermore, the spacer SP2 may be disposed on the bottom surface 11a1 of the first recess 11a after forming the current collector film 19 on the bottom surface 11a1 of the first recess 11a, or the current collector film 19 on the bottom surface 11a1 of the first recess 11a. It may be arranged on the bottom surface 11a1 of the first recess 11a before forming. Further, the spacer SP2 may be simply placed on the bottom surface 11a1 of the first recess 11a without being bonded, or fixed to the bottom surface 11a1 of the first recess 11a via a thermosetting adhesive such as an epoxy adhesive. You may do it.

<Effect obtained by electrochemical device (fourth embodiment)>
According to the electrochemical device, (Effect 1) to (Effect 3) described in <Effects obtained by the electrochemical device 10 (first embodiment)> in the << first embodiment >> In addition to (Effect 5) described in <Effects obtained by electrochemical device (third embodiment)> of Embodiment, the following (Effect 6) can be obtained.

  (Effect 6) Since it is not necessary to form the second concave portion 11b and the third concave portion 11d in the case 11 itself, the structure of the case 11 can be simplified. In particular, when the case 11 is made of ceramics such as alumina, a process is required in which an appropriate number of non-perforated unfired ceramic sheets and perforated unfired ceramic sheets are stacked and then pressed and fired. The number of parts can be reduced to simplify the process, and the unit price of the case 11 can be reduced.

  The present invention is not limited to electric double layer capacitors and lithium ion capacitors, but can be widely applied to other electrochemical devices using chargeable / dischargeable storage elements, such as redox capacitors and lithium ion batteries. The object described in [Problems to be solved by the invention] can be achieved.

  DESCRIPTION OF SYMBOLS 10 ... Electrochemical device, 11 ... Case, 11a ... 1st recessed part, 11a1 ... Bottom surface of 1st recessed part, 11b ... 2nd recessed part, 11b1 ... Bottom surface of 2nd recessed part, 11d ... 3rd recessed part, 11d1 ... 3rd recessed part Bottom surface, 12 ... Lid, 13 ... Power storage element, 13a ... First electrode sheet, 13b ... Second electrode sheet, 19 ... Current collecting film, 20 ... First conductive adhesive layer, 21 ... Second conductive adhesive layer, AR ... adhesive reservoir.

Claims (2)

An insulating case having a first recess, a conductive lid in which the first recess is closed in a watertight and airtight manner, a current collecting film made of a conductive material provided at the bottom of the first recess, and closed by the lid A chargeable / dischargeable power storage element enclosed in the first recess and an electrolyte solution, and a surface on one electrode side of the power storage element is disposed on the upper surface of the current collecting film via a first conductive adhesive layer. In the electrochemical device that is electrically connected and the surface on the other electrode side of the electricity storage element is electrically connected to the lower surface of the lid via a second conductive adhesive layer.
The electrochemical device is an electric double layer capacitor, a lithium ion capacitor or a redox capacitor,
On the bottom surface of the first recess, a second recess having an opening outline smaller than the outline of the surface on the one pole side of the electricity storage element and having a predetermined depth is formed.
The current collecting film has a thickness smaller than the depth of the second recess and is provided on the bottom surface of the second recess;
Between the bottom surface of the first recess and the top surface of the current collector film, there is an adhesive reservoir having a depth corresponding to a dimension obtained by subtracting the thickness of the current collector film from the depth of the second recess. Formed,
The first conductive adhesive layer is provided so as to fill the adhesive reservoir,
The outer peripheral portion of the surface on the one pole side of the electricity storage element is in direct contact with the bottom surface of the first recess,
An electrochemical device characterized by that. Between the first recess and the second recess, a third recess having an opening outline substantially coincident with the outline of the surface on the one pole side of the power storage element and having a predetermined depth is formed. ,
The outer peripheral portion of the surface on the one pole side of the electricity storage element is fitted in the third recess,
The electrochemical device according to claim 1.

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