JP6400301B2 - Electrochemical cell and method for producing the same - Google Patents

Description

  The present invention relates to an electrochemical cell such as an electric double layer capacitor, an ion capacitor, or a nonaqueous electrolyte battery.

  Small electrochemical cells such as electric double layer capacitors and secondary batteries using a non-aqueous electrolyte are used as backup power sources for electronic devices such as portable devices. Among these, an approximately rectangular parallelepiped (chip-shaped) electrochemical cell that can effectively use the mounting area is widely used.

  Conventionally, this chip-type electrochemical cell contains a positive and negative active material and an electrolyte in a ceramic case formed into a bottomed cylinder, and the upper part is sealed using a metal sealing plate It has a structure to do. On the other hand, in order to prevent the case from cracking due to heating in the reflow soldering process, a configuration has been proposed in which the container is made of a bottomed cylindrical case made of metal and a ceramic sealing plate that closes the opening of the case. (For example, refer to Patent Document 1). Such a configuration is expected in terms of cost reduction because the shape of the ceramic part is simple.

JP 2007-201382 A

  By the way, in the electrochemical cell of the structure which accommodates a positive electrode, a negative electrode, a separator, and electrolyte solution in the metal case formed in the bottomed cylindrical shape, and seals with a ceramic sealing board, it is made of the metal to which the negative electrode is connected. The case has a negative potential. The positive electrode is bonded to the inner surface of the sealing plate, and is located at the same height as the peripheral wall portion of the metal case. If the positive electrode is displaced from its original position due to manufacturing variations, there is a risk of short circuiting due to contact with the peripheral wall of the case.

Therefore, in an electrochemical cell having such a configuration, there is a demand for a configuration in which a metallic case having a negative potential and a positive electrode are not short-circuited even when the electrode is displaced.
The present invention has been made in view of such circumstances, and an object thereof is to provide a highly safe and inexpensive electrochemical cell.

The present invention provides the following means in order to solve the above problems.
The electrochemical cell according to the present invention includes a flat first container component, a second container component made of a bottomed cylindrical metal and forming a closed space with the first container component, An electrochemical cell comprising a positive electrode active material and a negative electrode active material housed in a closed space, an electrolyte, and a separator that separates the positive electrode active material and the negative electrode active material. A first external terminal and a second external terminal are provided on the outer lower surface, the first external terminal is electrically connected to the positive electrode active material, and the second external terminal is the second external terminal. It is electrically connected with the said negative electrode active material through the container structure part, and the insulator is formed in the inner side surface of the said 2nd container structure part.

  The electrochemical cell according to the present invention is a second container configuration that is formed of a flat plate-shaped first container component, a bottomed cylindrical metal, and forms a closed space with the first container component and the metal ring. A positive electrode active material and a negative electrode active material housed in the closed space, an electrolyte, and a separator that separates the positive electrode active material and the negative electrode active material, A first external terminal and a second external terminal are provided on the outer lower surface of the container component, the first external terminal is electrically connected to the positive electrode active material, and the second external terminal is It is electrically connected to the negative electrode active material through the second container component, and an insulator is formed on the inner side surface of the second container component.

According to the present invention, since the insulator is formed on the inner side surface of the second container component, the second container component and the positive electrode active material are electrically insulated. Thereby, even if a displacement occurs when fixing the positive electrode active material to the upper surface of the first container component, electrical insulation between the second container component and the positive electrode active material is maintained, It becomes a highly safe cell without short circuit.
Moreover, according to this invention, it can be set as the structure which joins a 1st container structure part and a 2nd container structure part via the seal ring previously formed in the periphery of the 1st container structure part. . Thereby, a 1st container structure part and a 2nd container structure part are joined favorably, and the electrochemical cell excellent in sealing property can be obtained. Furthermore, since the influence of welding heat on the first container component can be reduced, defects such as cracks in the container can be reduced, which is more preferable.

The electrochemical cell according to the present invention is characterized in that the insulator is formed outside the closed space and also on an upper plane of the second container component.
According to the present invention, the insulator is formed on the upper surface of the cell composed of the second container component made of metal. Thereby, after the cell is mounted on the circuit board or the like of the mounted device, the possibility of short-circuiting with the housing or other members can be reduced, which is more preferable.

In the electrochemical cell according to the present invention, the insulator is a heat-resistant resin film.
According to the present invention, the insulator coating can be easily formed. Moreover, since it does not change in quality at the time of reflow mounting by providing heat resistance, it is more preferable.

In the electrochemical cell according to the present invention, the insulator is a metal oxide or nitride.
According to the present invention, a metal oxide or nitride having high heat resistance is formed as an insulator. Thereby, even if it receives heat at the time of welding or subsequent reflow mounting, the insulator does not change in quality, and insulation between the second container component and the positive electrode active material can be maintained, which is more preferable.

In the electrochemical cell according to the present invention, the oxide is a metal thermal oxide film that forms the second container component.
According to the present invention, the thermal oxide film is formed integrally with the second container component. This thermal oxide film is more preferable because it has high durability and can maintain insulation between the second container component and the positive electrode active material over a long period of time.

In the electrochemical cell according to the present invention, the insulator has a thickness of 0.5 μm to 100 μm.
According to the present invention, sufficient insulation between the second container component and the positive electrode active material is ensured, and the strength of the insulator can be maintained. Furthermore, if the thickness of the said insulator is 1 micrometer-50 micrometers, since insulation and the intensity | strength of an insulator can be raised more, it is more preferable.

In the electrochemical cell according to the present invention, the first external terminal and the positive electrode active material are electrically connected via via wiring in the thickness direction of the first container component. .
According to the present invention, the possibility that the electrolytic solution reaches the via wiring is reduced, and the possibility of the anode dissolution of the via wiring can be greatly reduced, which is more preferable.

In the electrochemical cell according to the present invention, an interlayer wiring connected to the via wiring is provided inside the first container component.
According to the present invention, the number of wires exposed to the closed space containing the electrolytic solution can be reduced, and the possibility of anodic dissolution of the wires can be greatly reduced, which is more preferable.

In the electrochemical cell according to the present invention, the first container component is made of a ceramic containing at least one selected from the group consisting of alumina, silicon nitride, zirconia, silicon carbide, aluminum nitride, mullite, and a composite material thereof. It is characterized by becoming.
According to the present invention, an electrochemical cell having excellent heat resistance and durability is obtained, which is more preferable.

The method for producing an electrochemical cell according to the present invention includes a step of forming an insulator in a second container component made of a bottomed cylindrical metal, a flat first container component, and the second container. A step of housing a positive electrode active material and a negative electrode active material, an electrolyte, a separator for separating the positive electrode active material and the negative electrode active material in a closed space formed from the component, and the first container component; And a step of sealing the second container component by welding.
According to the present invention, an electrochemical cell having excellent hermeticity and high reliability can be obtained.

In the electrochemical cell manufacturing method of the present invention, in the step of forming the insulator, a heat-resistant resin or a metal oxide precursor is applied to the inner side surface of the second container component, and then the precursor is applied. A film of the heat resistant resin or metal oxide is formed by curing.
According to the present invention, an insulator having high insulating properties can be easily formed, which is more preferable.

  According to the present invention, even if the positive electrode active material and the second container component in the cell come into contact with each other, a short circuit due to electrical contact is prevented, and a highly safe and inexpensive surface mounted electrochemical cell is produced. Can be provided.

1 is a longitudinal sectional view of a chip-type electric double layer capacitor showing an embodiment according to the present invention. It is a longitudinal cross-sectional view which shows the modification of the electrical double layer capacitor shown in FIG. It is a longitudinal cross-sectional view which shows another modification of the electric double layer capacitor shown in FIG.

Hereinafter, embodiments of the electrochemical cell according to the present invention will be described.
The electrochemical cell described in the present invention specifically refers to a nonaqueous electrolyte battery, an electric double layer capacitor, or the like in which an active material used as a positive electrode or a negative electrode and an electrolytic solution are accommodated in a container.
In the present embodiment, a surface mount type electric double layer capacitor will be described as an example of an electrochemical cell.

An electric double layer capacitor which is an embodiment of an electrochemical cell of the present invention and a manufacturing method thereof will be described below with reference to the drawings.
As shown in FIG. 1A, an electric double layer capacitor 1 includes a flat sealing plate 3 (first container component), a metal case 2 (second container component), and the container. It is comprised from the electric power generation element 4 which consists of the positive electrode active material 13, the negative electrode active material 11, and the separator 12 which were accommodated in the interior space S formed inside and which were impregnated with the non-aqueous electrolyte (not shown). Yes.

  External terminals 6 and 7 connected to the via wirings 8 and 9 are formed on the sealing plate 3. The negative electrode active material 11 is electrically connected to the external terminal 7 through the case 2 and the via wiring 9. The positive electrode active material 13 is electrically connected to the external terminal 6 through the positive electrode current collector 5 and the via wiring 8. The positive electrode active material 13 and the negative electrode active material 11 are disposed to face each other with a separator 12 interposed therebetween.

Further, an insulator 14 is disposed on the inner side surface of the case 2. The case 2 having a negative potential can be kept electrically insulated from the positive electrode active material 13 by the insulator 14.
Furthermore, the electric double layer capacitor 1 is a capacitor that can be surface-mounted on a substrate (not shown) by, for example, reflow.

  The case 2 has a bottomed cylindrical shape, and the internal space S can store a positive electrode, a negative electrode, a separator, and an electrolytic solution. The opening end portion of the case 2 has a flange portion for sealing with the sealing plate 3. The case 2 can be made by pressing a metal plate.

  Examples of materials constituting the case 2 include stainless steel, Kovar (Co: 12% by weight, Ni: 29% by weight, Fe: alloy composed of the balance), Elinvar (Co: 12% by weight, Ni: 36% by weight, Use a nickel-containing material such as Fe: the alloy consisting of the remainder, Invar (Ni: 36 wt%, Fe: the alloy consisting of the remainder), 42-alloy (Ni: 42 wt%, Fe: the alloy consisting of the remainder), etc. Can do.

  In addition, a plating layer made of a noble metal having excellent corrosion resistance such as nickel or gold is formed on the surface of the case 2. The plating layer may be a single layer film or a laminated film composed of an underlayer and a finishing layer. As a method for forming these plating layers, for example, in addition to electrolytic plating and electroless plating, a vapor phase method such as vacuum deposition may be used. When the case 2 and the sealing plate 3 are welded, the case 2 and the sealing plate 3 are firmly joined by welding the plating layer of the case 2 and the brazing material on the sealing plate 3.

  The sealing plate 3 is a flat plate made of ceramic as shown in FIG. An external terminal 6 and an external terminal 7 are formed on one surface of the sealing plate 3. A case 2 is provided on the surface opposite to the surface on which the external terminals are formed. The case 2 and the sealing plate 3 are sealed by welding the flange portion of the case 2 and the sealing plate 3 via a brazing material. A positive electrode current collector 5 is formed on the surface of the sealing plate 3 that appears in the internal space S sealed by the case 2. The positive electrode current collector 5 is electrically connected to the positive electrode active material 13 accommodated in the internal space S. The external terminal 6 is electrically connected to the positive electrode active material 11 via the via wiring 8 and the positive electrode current collector 5. The external terminal 7 is electrically connected to the flange portion via the via wiring 9.

  In addition, a brazing material is formed at a location where the sealing plate 3 is joined to the case 2 at the peripheral edge of the upper surface. And in the electric double layer capacitor 1 of this embodiment, it is comprised in the state by which the case 2 and the sealing board 3 were sealed via the brazing material.

  As the material of the sealing plate 3, ceramic materials such as alumina, silicon nitride, zirconia, silicon carbide, aluminum nitride, and mullite can be used as described above. Examples of the brazing material include conventionally known brazing materials such as gold brazing and silver brazing.

  The sealing plate 3 is provided with external terminals 6 and 7 serving as a positive electrode or a negative electrode, and via wirings 8 and 9 for electrical connection to the positive electrode or the negative electrode, respectively. As shown in FIG. 1A, the structure of the terminal and via wiring is such that the positive or negative external terminals 6 and 7 and the positive or negative electrode are connected via via wirings 8 and 9 formed inside the sealing plate 3. Are electrically connected to each other. For the external terminals 6 and 7 and the via wirings 8 and 9, a metal having a melting point exceeding 1500 ° C., which is a firing temperature of ceramic, such as tungsten or molybdenum is used.

  The external terminals 6 and 7 and the via wirings 8 and 9 are preferably formed as follows. That is, a paste of metal such as tungsten or molybdenum is embedded in the ceramic green sheet corresponding to the sealing plate 3 or pattern printing is performed. And this ceramic green sheet is collectively sintered at high temperature. As a result, the external terminals 6 and 7 and the via wirings 8 and 9 can be collectively formed.

  The external terminals 6 and 7 and the via wirings 8 and 9 may be further formed with a single layer film or a multilayer metal film by plating or sputtering. For example, by forming a nickel thin film on the base and a gold thin film on the surface by plating, it is possible to implement a good mounting on the substrate of the mounted device.

  A positive electrode current collector 5 is formed on the upper portion of the sealing plate 3 formed in this manner in order to electrically connect the positive electrode side via wiring 8 and the positive electrode active material 13. The positive electrode current collector 5 covers an exposed portion in the internal space S of the via wiring 8 on the positive electrode side, and further covers this exposed portion and the surface in contact with the internal space S of the sealing plate 3 continuously. Thereby, it is possible to prevent the non-aqueous electrolyte from entering the exposed portion in the internal space S of the via wiring 8 on the positive electrode side.

  The via wiring 8 exposes only the minimum upper end face necessary for electrical connection between the positive electrode active material 13 and the external terminal 6 in the internal space S. Further, the positive electrode current collector 5 having higher corrosion resistance is formed on the via wiring 8 to protect the via wiring 8. Thereby, even if a pinhole or the like exists in the positive electrode current collector 5, the possibility that the electrolytic solution reaches the via wiring 8 can be reduced.

  The positive electrode current collector 5 is preferably formed of a material that is not corroded by the electrolytic solution in order to contact the electrolytic solution. Examples of the metal having such properties include titanium, tantalum, niobium, and zirconium as valve metals, and aluminum is particularly preferable. By forming the positive electrode current collector 5 from a valve metal, the via wiring 8 can be protected from electrolytic corrosion.

  The power generation element 4 is stacked with a positive electrode active material 13 electrically connected to the upper surface of the sealing plate 3 via a positive electrode current collector 5 and a separator 12 sandwiched between the positive electrode active material 13 and a non-aqueous electrolyte. And a negative electrode active material 11 that moves cations or anions such as lithium ions to and from the positive electrode active material 13. The positive electrode active material 13, the negative electrode active material 11, and the separator 12 are impregnated with a non-aqueous electrolyte solution (not shown).

  The positive electrode active material 13 and the positive electrode current collector 5 are bonded and fixed by a conductive adhesive obtained by mixing a carbon material such as graphite or amorphous carbon with a resin material such as phenol resin. Thus, the positive electrode active material 13 is electrically connected to one external terminal 6 via the positive electrode current collector 5 and the via wiring 8.

  Similarly, the negative electrode active material 11 and the case 2 are bonded with a conductive adhesive. Thus, the negative electrode active material 11 is electrically connected to the other external terminal 7 through the case 2 and the via wiring 9.

  The positive electrode active material 13 and the negative electrode active material 11 are polarizable electrodes in which cations or anions move between them via a non-aqueous electrolyte, and the cations or anions can be adsorbed and desorbed. For example, it is produced by mixing activated carbon, a conductive material, and a binder such as polytetrafluoroethylene at a predetermined ratio and then molding at a predetermined molding pressure.

  The separator 12 is a member that separates the positive electrode active material 13 and the negative electrode active material 11 and restricts direct contact between both electrodes, and uses an insulator having a large ion permeability and mechanical strength. Can do. In consideration of the thermal influence during reflow soldering and welding between the case 2 and the sealing plate 3, a material excellent in thermal and mechanical resistance is preferable for the separator 12. For example, in addition to glass fibers, resins such as polyphenylene sulfide, polyamide, polyimide, and polytetrafluoroethylene can be used.

The non-aqueous electrolyte is, for example, an electrolyte in which a quaternary ammonium salt such as TEABF ₄ salt from which water has been removed is dissolved as a supporting salt in an aprotic polar organic solvent from which water has been previously removed to 100 ppm or less. It is sufficient that at least the positive electrode active material 13, the negative electrode active material 11, and the separator 12 are present in the internal space S in a state in which the electrolytic solution is impregnated. In particular, if the positive electrode active material 13 and the negative electrode active material 11 are sufficiently impregnated with the electrolytic solution, and there is no electrolytic solution in the vicinity of the joint between the case 2 and the sealing plate 3 in the internal space S, electrolysis by heat during welding It is more preferable that liquid does not evaporate.

  In addition, an insulator 14 is coated on the side surface of the case 2 inside the internal space S. Since the bottom portion of the case 2 is electrically connected to the negative electrode active material 11, the insulator 14 is not formed at a location where the bottom portion of the case 2 is electrically connected to the negative electrode active material 11, and the internal space S It is formed on the side. Since the insulator 14 is formed on the side surface of the internal space S, the insulator 14 is interposed between the case 2 having a negative potential even if the positive electrode active material 13 having a positive potential is displaced. Since it is formed, the positive electrode active material 14 and the case 2 having a negative potential are not in electrical contact.

  The insulator 14 does not necessarily have to be formed on the entire side surface of the internal space S. If the insulator 14 is formed at least up to the height of the side surface of the positive electrode active material 13, it is assumed that misalignment occurs when the positive electrode active material 13 is bonded. In addition, insulation between the positive electrode active material 13 and the case 2 can be maintained.

  Further, the insulator 14 may be formed outside the internal space S in addition to the side surface of the internal space S. For example, as shown in FIG. 1B, if an insulator 24 is further formed on the upper surface outside the case 2, the upper plane of the case 2 having a negative potential can be insulated. Thus, even if the cell is mounted on the substrate of the mounted device and then contacted with the conductive member, short circuit of the substrate circuit can be prevented.

  On the other hand, the case 2 and the negative electrode active material 11 are electrically connected by being bonded via a conductive adhesive. If the insulator 14 is formed on the adhesion surface, adhesion failure between the case 2 and the negative electrode active material 11 occurs, which causes an increase in resistance. In particular, when the insulator 14 is formed on the entire bonding surface, it is electrically insulated and does not function as an element. For this reason, it is preferable that the insulator 14 is formed avoiding this adhesion surface.

Furthermore, the case 2 and the sealing plate 3 are joined by welding such as resistance welding, laser welding, or ultrasonic welding. Particularly in the case of resistance welding or laser welding, high heat exceeding 1000 ° C. is brought to the joint. If the insulator 14 is in contact with this joint, it is affected by oxidation, thermal decomposition, cracks, etc. of the film. In particular, the insulator 14 formed on the outer side surface of the case 2 causes poor appearance. Furthermore, since the insulator 14 is in contact with the joint, it causes welding failure and the sealing performance is deteriorated. For this reason, it is preferable that the insulator 14 is not formed at the junction and is not in contact with the junction.
The insulator 14 can be formed of a heat resistant resin, a glass coating film, a metal oxide film of the case 2, or the like.

  As the heat-resistant resin, for example, various thermosetting resins and ultraviolet curable resins such as an epoxy resin, a polyimide resin, a polyamideimide resin, and a silicone resin can be used. It can also be obtained by forming a thin film of polyimide, parylene, or the like by vapor deposition. Any heat-resistant resin can be used as long as it can withstand the high heat of 200 to 300 ° C. brought about during reflow mounting. These resins are preferable because an insulating coating can be easily formed by applying a liquid precursor and then curing.

  The insulator 14 can be a metal oxide or nitride. Oxides and nitrides have a high melting point and are not affected by heat in welding, reflow mounting, and the like, and therefore are suitable as materials for the insulator 14. As a metal, various metals, such as nickel and chromium which comprise the stainless steel used for case 2 other than silicon and aluminum, can be used, for example.

  The insulator 14 formed of such a metal oxide or nitride can be a glass coating such as a silica coating formed by applying and drying silicone resin, alkoxysilane, polysilazane, or the like. . Moreover, it can be set as thin films, such as a silicon oxide and a silicon nitride, formed by a vapor phase growth method.

  Furthermore, the oxide used for the insulator 14 may be a thermal oxide film formed on the case 2. In this case, a thermal oxide film is formed on the entire surface including the outer side surface of the case 2. In this case, even if a thermal oxide film is formed on the bonding surface between the case 2 and the sealing plate 3, the influence on the bonding is small, and the insulating portion can be formed more easily. The case 2 is formed into a bottomed cylindrical shape by a press or the like, and then heat-treated in an oxidizing atmosphere furnace to form a thermal oxide film. Thereafter, the oxide film on the surface to which the negative electrode active material 11 is bonded is removed. Since the thermal oxide film formed in this way is formed integrally with the case 2, the thermal oxide film has good adhesion, and has durability against the influence of heat during welding and reflow mounting and during long-term use. For this reason, insulation between the case 2 and the positive electrode active material 13 can be maintained over a long period of time.

  The thickness of the insulator 14 is only required to be formed so that insulation is maintained even when the case 2 and the positive electrode active material 13 are in contact with each other. it can. Although the lower limit of the thickness depends on the material, for example, if it is 0.5 μm, insulation between the case 2 and the positive electrode active material 13 can be maintained. Moreover, if thickness is 1 micrometer, since insulation can fully be maintained, it is especially preferable. On the other hand, the upper limit of the thickness is not particularly limited because the insulating property improves as the thickness increases. However, even if the thickness is thicker than necessary, the processing time of the film forming process becomes long and the manufacturing cost increases. In addition, if the thickness of the insulator 14 is large, it is necessary to reduce the thickness of the positive electrode active material 13 and the negative electrode active material 11 due to the size and the like in the container, and the capacity of the electric double layer capacitor is reduced. End up. For this reason, the thickness is preferably smaller than 300 μm, more preferably 100 μm or less. In addition, when the insulator 14 is a thin film, the thickness is more preferably 50 μm because it may not have durability due to long-term use when the thickness is more than necessary.

Next, the manufacturing method of the electric double layer capacitor which is the electrochemical cell of this invention is demonstrated.
A method for manufacturing an electric double layer capacitor, which is a preferred aspect of the present embodiment, is a method for manufacturing the electric double layer capacitor 1 having the above-described configuration, and includes a step of forming an insulator 14 on the case 2 and a formation on the sealing plate 3. After forming the positive electrode active material 13 on the current collector 5, the separator 12 is formed, and then the negative electrode active material 11 connected to the case 2 is formed so as to be connected to the separator 12. The method includes at least the step of connecting the positive electrode active material 13 and the negative electrode active material 11 and the step of welding and sealing the case 2 and the sealing plate 3.

  In this embodiment, first, the insulator 14 is formed on the case 2. Various methods can be used depending on the type of the insulator 14, and here, description will be made by taking polyimide, which is a heat-resistant thermosetting resin, as an example. Specifically, a solution of polyamic acid, which is a polyimide precursor, is prepared by appropriately diluting with a solvent in accordance with the thickness of the insulator 14 to be formed. This solution is applied to the surface of the case 2 on which the insulator 14 is formed using a dispenser or the like. Thereafter, the case 2 to which the solution is applied is heat-treated and cured to the thermosetting temperature of the polyimide, thereby forming a polyimide film on the case 2.

  For other insulator materials, the dispenser can be used as a coating method, or a solution such as a sponge can be impregnated with a porous material and pressed against the surface of the case 2 where the insulator 14 is formed. Can do. When the insulator 14 is formed by vapor deposition, the thin film can be deposited after masking the bonding surface inside the case 2 and the bonding surface with the negative electrode active material 11 in advance.

  As described above, as a material that can form a thin film precursor serving as an insulator in a case in advance, the polyamic acid that is a precursor of the polyimide, and a silicone resin that is a precursor of a silica coating that is silicon oxide. , Alkoxysilane, polysilazane, and the like. It is preferable to use these liquid precursors because the insulator 14 can be easily formed.

  Next, the negative electrode active material 11 is bonded to the bottom of the concave surface of the case 2 where the insulator 14 is formed via a conductive adhesive. Also, a conductive adhesive is applied on the positive electrode current collector 5 formed on the sealing plate 3 to adhere the positive electrode active material 13. The case 2 to which the negative electrode active material 11 is bonded and the sealing plate 3 to which the positive electrode active material 13 is bonded are heat-treated to cure the conductive adhesive and dry the electrode. The non-aqueous electrolyte is injected and impregnated into the electrode thus dried.

  Then, the separator 12 is placed on the positive electrode active material 13 on the sealing plate 3, and then the case 2 to which the negative electrode active material 11 is connected is overlaid on the sealing plate 3. Thereby, the positive electrode active material 13 and the negative electrode active material 11 are connected via the separator 12. In this way, the positive electrode active material 13, the negative electrode active material 11, the separator 12, and the nonaqueous electrolyte are accommodated in the internal space S formed by the case 2 and the sealing plate 3.

  Next, the joint between the case 2 and the sealing plate 3 is welded, and the case 2 and the sealing plate 3 seal the container. At this time, the method for welding the case 2 and the sealing plate 3 is not particularly limited. For example, in addition to seam welding by resistance welding by bringing a roller electrode into contact, laser welding, ultrasonic welding, and the like can be given. When such seam welding is used, the nickel plating of the case 2 and the brazing material formed on the sealing plate 3 can be welded.

Next, as a modification of the electrochemical cell of the present invention, a surface mount type electric double layer capacitor shown in FIG. 2 will be described as an example.
The electric double layer capacitor 10 shown in FIG. 2 is similar to the electric double layer capacitor 1 of FIG. 1 in a non-aqueous electrolyte (inside the internal space S formed inside the container formed by the case 2 and the sealing plate 30. A power generation element 4 including a positive electrode active material 13, a negative electrode active material 11, and a separator 12 impregnated with (not shown) is accommodated.

  Similarly to the electric double layer capacitor 1 of FIG. 1, an insulator 14 is formed on the side surface of the case 2 in the internal space S of the electric double layer capacitor 10 of FIG. Thereby, even if position shift arises when forming the positive electrode active material 13 on the sealing board 30, since the case 2 and the positive electrode active material 13 are electrically insulated, a short circuit can be prevented.

  In the present modification, positive and negative external terminals 6 and 7 are provided on the lower surface of the sealing plate 30. An external wiring 15 is provided on one side surface of the sealing plate 30. The external wiring 15 can electrically connect the positive external terminal 6 and the positive electrode active material 13 via the interlayer wiring 17 and the via wiring 18 formed inside the sealing plate 30. An external wiring 16 is provided on the other side surface of the sealing plate 30. The external terminal 7 on the negative electrode side and the negative electrode active material 11 are electrically connected via the external wiring 16. On the sealing plate 30, a current collector 5 that electrically connects the via wiring 8 on the positive electrode side and the positive electrode active material 13 is also formed.

  The positive electrode current collector 5 covers an exposed portion in the internal space S of the via wiring 18, and further continuously covers the exposed portion and the surface in contact with the internal space S of the sealing plate 30. As a result, it is possible to prevent the nonaqueous electrolyte from entering the exposed portion of the internal space S of the via wiring 18.

  As shown in FIG. 2, the interlayer wiring 17 and the via wiring 18 are formed singularly, a plurality of interlayer wirings connected to the external wiring 15 are formed, and a plurality of via wirings corresponding to each interlayer wiring are formed. May be. Thereby, even if one of the plurality of via wirings is corroded by anodic dissolution, electrical connection between the positive electrode active material 13 and the external terminal 6 can be maintained by the remaining via wiring and interlayer wiring.

  The positive electrode active material 13 and the positive electrode current collector 5 are bonded to each other with a conductive adhesive in which a carbon material such as graphite or amorphous carbon is mixed with a resin material such as a phenol resin. Thus, the positive electrode active material 13 is electrically connected to one external terminal 6 through the positive electrode current collector 5, the via wiring 18, the interlayer wiring 17, and the external wiring 15.

Similarly, the negative electrode active material 11 and the case 2 are bonded with a conductive adhesive. Thus, the negative electrode active material 11 is electrically connected to the other external terminal 7 via the case 2 and the external wiring 16.
Furthermore, as another modified example of the electrochemical cell of the present invention, a surface mount type electric double layer capacitor shown in FIG. 3 will be described as an example.

  The electric double layer capacitor 20 shown in FIG. 3 is impregnated with a non-aqueous electrolyte (not shown) in an internal space S formed inside a container composed of a case 21, a seal ring 22, and a sealing plate 30. The power generation element 4 including the positive electrode active material 13, the negative electrode active material 11, and the separator 12 is accommodated.

  Further, similarly to the electric double layer capacitor 1 of FIG. 1, an insulator 14 is formed on the side surface of the case 21 in the internal space S of the electric double layer capacitor 20 of FIG. 3. Thereby, even if position shift arises when forming the positive electrode active material 13 on the sealing board 30, since the case 21 and the positive electrode active material 13 are electrically insulated, a short circuit can be prevented.

  A seal ring 22 is bonded to the upper end portion of the sealing plate 30 in advance via a bonding material. As the bonding material, for example, a brazing material such as Ag-Cu brazing is used. The seal ring 22 joined to the sealing plate 30 and the case 21 are overlapped and welded. As a welding method, seam welding by contacting a roller electrode, laser welding, ultrasonic welding, or the like is used.

  The case 21 and the sealing plate 3 are joined via a joining material (not shown), and an internal space S is formed. As the bonding material, for example, a brazing material such as Ag-Cu brazing is used. The bonding material is previously applied to the bonding surface on the sealing plate 3, and the case 2 is overlapped thereon and welded. As a welding method, seam welding by contacting a roller electrode, laser welding, ultrasonic welding, or the like is used.

  Thereby, the case 2 is airtightly joined to the sealing plate 3 via the seal ring 22. A space defined by the sealing plate 30 and the case 2 is an internal space S that is hermetically sealed.

  In addition, the seal ring 22 of this embodiment is formed from the metal material containing nickel. Specifically, it is one selected from Kovar, Elinvar, Invar, and 42-alloy, but is not limited thereto.

In particular, the seal ring 22 is preferably made of a material having a thermal expansion coefficient close to that of the sealing plate 3. For example, when the sealing plate 3 is formed using alumina having a thermal expansion coefficient of 6.8 × 10 ⁻⁶ / ° C., the seal ring 22 may be Kovar having a thermal expansion coefficient of 5.2 × 10 ⁻⁶ / ° C. or thermal expansion. It is preferable to use 42-alloy having a coefficient of 4.5 to 6.5 × 10 ⁻⁶ / ° C., a nickel base alloy, or the like.

  Further, the case 21 of the present modification is also formed of a metal material containing nickel, similar to the seal ring 22. Specifically, it is one selected from Kovar, Elinvar, Invar, and 42-alloy. Also in this case, a material having a thermal expansion coefficient close to that of the sealing plate 30 is preferable.

  Furthermore, a plating layer is formed on the surface of the case 21 and the seal ring 22. Examples of the plating layer include noble metals having excellent corrosion resistance such as nickel and gold. The plating layer may be a single layer film or a laminated film composed of an underlayer and a finishing layer. As a method for forming these plating layers, for example, in addition to electrolytic plating and electroless plating, a vapor phase method such as vacuum deposition may be used. When the case 21 and the sealing plate 30 are welded, one or both of the plated layers of the case 21 and the seal ring 22 are melted, whereby the case 21 and the seal ring 22 are firmly joined.

  The negative electrode active material 11 and the case 21 are bonded via a conductive adhesive. The case 21 is in contact with the seal ring 22, and the seal ring 22 is in contact with the external wiring 16. Thereby, the external terminal 7 and the negative electrode active material 11 are electrically connected.

  In the present modification, positive and negative external terminals 6 and 7 are provided on the lower surface of the sealing plate 30. An external wiring 15 is provided on one side surface of the sealing plate 30. The external wiring 15 can electrically connect the positive-side external terminal 6 and the positive electrode 13 via the interlayer wiring 17 and the via wiring 18 formed inside the sealing plate 30.

  An external wiring 16 is provided on the other side surface of the sealing plate 30. The external terminal 7 on the negative electrode side and the negative electrode active material 11 are electrically connected via the external wiring 16. Also formed on the sealing plate 30 is a positive electrode current collector 5 that electrically connects the via wiring 8 on the positive electrode side and the positive electrode active material 13.

  The positive electrode active material 13 and the positive electrode current collector 5 are bonded to each other with a conductive adhesive in which a carbon material such as graphite or amorphous carbon is mixed with a resin material such as a phenol resin. Thus, the positive electrode 13 is electrically connected to one of the external terminals 6 via the current collector 5, via wiring 18, interlayer wiring 17, and external wiring 15.

  Similarly, the negative electrode active material 11 and the case 21 are bonded with a conductive adhesive. Thereby, the negative electrode active material 11 is electrically connected to the other external terminal 7 through the case 21, the seal ring 22, and the external wiring 16.

  In the embodiment using the seal ring 22, in addition to the present modification shown in FIG. 3, a configuration in which the seal ring is arranged between the case 2 and the sealing plate 3 in the embodiment shown in FIG.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, an electric double layer capacitor has been described as an example of an electrochemical cell, but the present invention is not limited to this case. The present invention can also be applied to other electrochemical devices such as secondary batteries that involve oxidation / reduction reactions. For example, the present invention can be applied to a lithium secondary battery using a material capable of inserting and extracting metal lithium ions as an active material of a positive electrode or a negative electrode. In particular, a lithium-ion capacitor or a lithium-ion secondary battery in which a carbon-based material or a silicon-based material that can store lithium ions in advance is used as the negative electrode active material and lithium ions are doped in advance may be used. The present invention is also applicable to a lithium ion capacitor in which at least one of a positive electrode and a negative electrode is combined with an electrode such as activated carbon used in an electric double layer capacitor.

S: Internal space 1, 10, 20 ... Electric double layer capacitor (electrochemical cell)
2, 21 ... Case 3, 30 ... Sealing plate 4 ... Power generation element 5 ... Positive electrode current collector 11 ... Negative electrode active material 12 ... Separator 13 ... Positive electrode active material 14, 24 ... Insulator 6, 7 ... External terminal 8, 9, 18 ... Via wiring 15, 16 ... External wiring 17 ... Interlayer wiring 22 ... Seal ring

Claims (9)

A flat plate-like first container component made of ceramic, a second container component made of a bottomed cylindrical metal and forming a closed space with the first container component, and housed in the closed space An electrochemical cell comprising a positive electrode active material and a negative electrode active material, an electrolyte, and a separator that separates the positive electrode active material and the negative electrode active material,
A first external terminal and a second external terminal are provided on the outer lower surface of the first container component,
The first external terminal is electrically connected to the positive electrode active material,
The second external terminal is electrically connected to the negative electrode active material via the second container component,
An electrochemical cell, wherein a film of a heat-resistant resin is formed at least at a position higher than the height of the positive electrode active material on the inner side surface of the second container component. A flat first container component, a second container component made of bottomed cylindrical metal and forming a closed space with the first container component and the metal ring, and housed in the closed space. A positive electrode active material and a negative electrode active material, an electrolyte, and a separator that separates the positive electrode active material and the negative electrode active material,
A first external terminal and a second external terminal are provided on the outer lower surface of the first container component,
The first external terminal is electrically connected to the positive electrode active material,
The second external terminal is electrically connected to the negative electrode active material via the second container component,
An electrochemical cell, wherein a film of a heat-resistant resin is formed at least at a position higher than the height of the positive electrode active material on the inner side surface of the second container component. 3. The electrochemical cell according to claim 1, wherein the heat-resistant resin film is also formed on the upper plane of the second container component outside the closed space. 4. The electrochemical cell according to any one of claims 1 to 3 , wherein a thickness of the heat-resistant resin film is 0.5 µm to 100 µm. The electrochemical cell according to any one of claims 1 to 3 , wherein a thickness of the heat-resistant resin film is 1 µm to 50 µm. The said 1st external terminal and the said positive electrode active material are electrically connected through the via wiring of the thickness direction of a said 1st container structure part, The any one of Claim 1 to 5 characterized by the above-mentioned. The electrochemical cell according to item. The electrochemical cell according to claim 6 , wherein an interlayer wiring connected to the via wiring is provided inside the first container component. 2. The first container component is made of a ceramic containing at least one selected from the group consisting of alumina, silicon nitride, zirconia, silicon carbide, aluminum nitride, mullite, and a composite material thereof. The electrochemical cell according to any one of 1 to 7 . Forming a heat-resistant resin film on the second container component made of bottomed cylindrical metal;
A positive electrode active material, a negative electrode active material, an electrolyte, and the positive electrode active material and the negative electrode active material are separated in a closed space formed by a flat plate-like first container component and the second container component. Storing the separator;
Ri Do and a step of sealing by welding and the second container structure portion and the first container component,
In the step of forming a film of the heat resistant resin, the precursor of the heat resistant resin is applied to at least a position higher than the height of the positive electrode active material among the inner side surfaces of the second container component, and then A method for producing an electrochemical cell, comprising curing a precursor.

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