JP6916081B2 - How to manufacture an electrochemical cell - Google Patents

Description

The present invention relates to a process for the production of electrical cell.

Electrochemical cells such as non-aqueous electrolyte secondary batteries and electric double layer capacitors are power storage devices used for supporting data writing to a memory when a momentary power failure occurs and for smoothing circuit voltage. In order to improve the long-term reliability of this electrochemical cell, a ceramic substrate made of alumina or the like is sealed with a lid made of a metal or alloy having a coefficient of thermal expansion similar to that of the substrate, and a structure having excellent airtightness is provided. It has been adopted.

In such a container configuration, it is possible to adopt a configuration of an electrochemical cell in which a power storage element formed by winding or laminating electrodes is housed inside the container. Such an electrochemical cell has a low resistance of the power storage element and can handle a large current, but further ensures an electrical connection between the power storage element and the current collector provided inside the container. Therefore, the cell can have a low resistance without being affected by the contact resistance or the like.

For example, a configuration has been proposed in which an aluminum pad film provided inside a ceramic base and an aluminum cell lead, which is an extension of a power storage element, are connected by ultrasonic welding, laser welding, or the like (patented). Reference 1). In this configuration, since the pad film and the cell lead are made of aluminum, they can be easily bonded by welding such as ultrasonic welding. In addition, the contact resistance between the pad film and the cell lead is sufficiently small.

Japanese Unexamined Patent Publication No. 2013-30750

In the above-mentioned container configuration, the ceramic base is manufactured by laminating a plurality of ceramic green sheets and integrally sintering them with a refractory material such as tungsten constituting a wiring pattern. On the other hand, the pad film formed inside the base is made of aluminum and has a melting point much lower than the sintering temperature, so that it cannot be integrally formed with the base body. Therefore, after sintering, it is necessary to form a pad film by another process such as thin film deposition or sputtering.

The aluminum pad film also has a function as a protective film against a wiring pattern made of tungsten or the like formed inside the base. However, conventionally, due to film defects such as pinholes in the pad film, the electrolyte permeates the inside of the protective film from the film defects and reaches the wiring pattern, which may deteriorate the corrosion resistance. Therefore, in order for the aluminum constituting the pad film to function as a protective film against the wiring pattern, it is necessary to have a sufficient thickness and a structure free of defects such as cracks. It was necessary to process the above process for a long time. That is, such a pad film forming process has been a major factor in increasing the cost.

In view of these problems, the present invention is excellent in mass productivity and reliability, as an inexpensive configuration relating to the container configuration and connection with the power storage element, and sufficient protection of the wiring inside the container from the electrolyte. The subject is to provide an electrochemical cell.

As a result of diligent studies, the inventors have made that the pad film formed on the wiring pattern formed on the inner bottom surface of the container is made of a material such as an aluminum thin film or nickel plating, which does not necessarily have sufficient corrosion resistance against anode corrosion. Even if this is the case, by covering the joint with the cell lead extending from the power storage element and the pad film with an insulating protective layer, it is possible to obtain a highly mass-producible, low-cost configuration with excellent reliability. I found it.

That is, the electrochemical cell in the present invention is an electrochemical cell in which a power storage element is housed in a storage container including a base and a sealing plate, and the base is made of an insulating material and has a pair of connections to the bottom. A terminal is formed, a pair of pad films connecting to the cell lead of the power storage element is formed inside the storage container, and a wiring for electrically connecting the connection terminal and the pad film is formed, and the cell lead and the cell lead are formed. The pad film is covered with an insulating coating portion in a state of being connected to the pad film.

According to the present invention, a pad film composed of a coarse film or thin film of aluminum or a plating layer such as nickel or gold, which is simpler than the conventional one and does not necessarily have sufficient corrosion resistance against anode corrosion, is coated with an insulating coating. By doing so, it is possible to prevent the pad film or the lower layer wiring from coming into contact with the electrolyte. In addition, by making the covering portion insulating, it is possible to prevent a short circuit between the pad films on the positive electrode side and the negative electrode side formed on the bottom surface of the base, so that the covering portion can be formed over both pad films. It is possible to form a covering portion efficiently. Therefore, it is possible to obtain an electrochemical cell that is cheaper than the conventional configuration and has excellent reliability.

In the present invention, the coating portion preferably contains an insulating resin and an inorganic compound. Further, it is more preferable that the inorganic compound is contained in the coating portion in an amount of 10 to 80% by mass. Alternatively, it is preferable that the covering portion is made of a polyimide resin.

According to the present invention, by forming the coating portion from an insulating resin and an inorganic compound, in addition to the heat resistance and durability of the inorganic compound, sufficient coating property can be obtained from the insulating resin. Therefore, by combining these, sufficient corrosion resistance can be provided. Further, by configuring the coating portion to be made of polyimide having sufficient heat resistance, corrosion resistance, and durability, the coating having sufficient corrosion resistance is similar to the combination of the insulating resin and the inorganic compound described above. Can be a department.

The present invention is characterized in that the pad film is composed of a plating layer.

According to the present invention, by forming the plating layer as the pad film, in addition to being able to obtain an inexpensive pad film, the wiring can be protected to some extent from the electrolyte, so that sufficient corrosion resistance can be obtained in combination with the covering portion. Obtainable.

The present invention is characterized in that the pad film is made of aluminum having a thickness of 1 μm or more and less than 10 μm.

According to the present invention, by using the aluminum thin film as the pad film, it is possible to protect the wiring pattern such as via wiring from the electrolyte to some extent, and it is possible to sufficiently maintain the bonding strength of the cell leads. Further, since the film formation time can be shortened as compared with the conventional thick film, the manufacturing cost can be reduced even when combined with the coating portion of the present invention.

The method for manufacturing an electrochemical cell in the present invention is a method for manufacturing an electrochemical cell in which a power storage element is housed in a storage container including a base and a sealing plate, and is made of an insulating material and has a connection terminal and wiring integrated. forming a pad film is formed the base, a step of connecting the cell read of the electric storage element to the pad film, the step of covering said pad layer, wherein the cell read is connected with an insulating coating portion, It is characterized by including a step of sealing the base with the sealing plate.

According to the present invention, the cell can be manufactured at low cost while maintaining the corrosion resistance of the wiring pattern such as the via wiring inside the container of the electrochemical cell.

According to the present invention, for a small electrochemical cell capable of supplying a large current with excellent long-term reliability, an inexpensive configuration regarding a container configuration and a connection with a power storage element is adopted, and the wiring inside the container is made from an electrolyte. By providing sufficient protection, it is possible to provide an electrochemical cell having excellent mass productivity and reliability. In addition, such a small electrochemical cell can be manufactured at low cost.

It is the schematic which shows the electrochemical cell of embodiment which concerns on this invention. It is sectional drawing which shows the detail of the electrochemical cell of embodiment which concerns on this invention. It is a top view of the base of the embodiment of the present invention, and is a schematic view showing the positional relationship between the pad film and the wiring on the bottom surface of the base. It is sectional drawing which shows the detail of the electrochemical cell of embodiment which concerns on this invention, and is the figure which shows the positional relationship between the covering part 11 and other members.

Hereinafter, embodiments of the electrochemical cell of the present invention will be mentioned, and each configuration thereof will be described in detail with reference to the drawings.

(Outline of the present invention)
FIG. 1 is an external view of the electrochemical cell 1 of the present embodiment. Although the electrochemical cell 1 is shown in a rectangular parallelepiped shape as an example, it can have various sizes and shapes such as a track shape and a cylindrical shape. The size can be, for example, 10 mm in length × 8 mm in width × 1.8 mm in height, but is not limited to this, and is about 2 to 20 mm on a side and about 0.5 to 3 mm in height depending on the required characteristics of the cell. Can be.

In the present embodiment, the electrochemical cell 1 includes a storage container 12 including a base 2 for storing a power storage element 6 described later and a sealing plate 10 for airtightly closing the opening of the base 2. The base 2 is formed in a concave shape with an opening at the upper end, and a metal seal ring 9 is attached to the upper end thereof by brazing or the like. By joining the seal ring 9 and the sealing plate 10, the base 2 and the sealing plate 10 are integrated into a storage container 12.

FIG. 2A is a diagram showing an AA cross section of FIG. This AA cross section is a surface including the wiring 3 for the purpose of explaining the wiring 3 described later. The base 2 constituting the storage container 12 of the electrochemical cell 1 is a container made of box-shaped (concave) ceramics having an opening at the upper side, and is formed on a rectangular base bottom 2a and an outer edge of the base bottom 2a. It has an erected rectangular frame-shaped base peripheral wall portion 2b. The base bottom 2a has a base bottom surface 2c, which is the inner bottom surface of the concave base 2, and a base bottom surface 2d, which is the outer bottom surface.

A connection terminal 4 for electrically connecting the mounted device and the power storage element 6 of the electrochemical cell 1 is formed on the lower surface 2d of the base. The electrochemical cell 1 is mounted and incorporated on the circuit board by joining the connection terminal 4 and the circuit board of the mounted device by reflow soldering or the like. Further, inside the base bottom portion 2a, a wiring 3 for electrically connecting the connection terminal 4 and the power storage element 6 is formed. The wiring 3 is integrally formed with the connection terminal 4 as described later, is exposed on the inner surface of the base 2 at the position of the bottom surface 2c of the base, and is electrically connected to the power storage element 6 via the pad film 5 or the like. ..

In the power storage element 6, a set of electrode sheets composed of an active material and a metal leaf current collector supporting the active material is integrated by winding, laminating, folding, or the like via an insulating separator. Structure. Cell leads 8 are formed at the ends of the current collectors of the positive electrode and the negative electrode, respectively.

In the present embodiment, the pad film 5 is formed at the position of the bottom surface 2c of the base over the exposed surface of the wiring 3 inside the container and its surroundings. As shown in FIG. 2A, a plurality of positive electrode and negative electrode wirings 3 can be formed. At this time, the exposed surfaces of the plurality of wirings 3 can be covered, and the pad film 5 can be formed on the bottom surface 2c of the base around the exposed surfaces.

Then, in the present embodiment, the pad film 5 and the cell lead 8 extending from the power storage element 6 are joined to electrically connect the power storage element 6 and the connection terminal 4. The cell lead 8 is formed in a ribbon shape and is in surface contact with the pad film 5 at the position of the joint portion 13. Then, both are joined by ultrasonic welding. Further, the cell lead 8 is folded back into a U shape at the position of the AA cross section and is connected to the power storage element 6.

In the present embodiment, the bonding portion 13 between the pad film 5 and the pad film 5 of the cell leads 8 bonded to the pad film 5 is covered with a covering portion 11 described later. Specifically, the entire pad film 5 and the entire portion of the cell lead 8 that is in surface contact with the pad film 5 are covered with the coating layer 11, and the U-shaped folded portion of the cell lead 8 extends to the power storage element 6. The portion is a structure not covered by the coating layer 11.

In the present invention, the pad film 5 and the cell lead 8 are joined to each other, and the pad film 5 and the joining portion 13 are covered with the covering portion 11. Can be adequately protected.

Hereinafter, each configuration will be described in detail.

(base)
As described above, the base 2 is a container made of box-shaped ceramics having an opening at the top, and has a rectangular base bottom 2a and a rectangular frame-shaped base erected on the outer edge of the base bottom 2a. It has a peripheral wall portion 2b.

As shown in FIG. 2A, the wiring 3 is a via wiring embedded in a via hole formed in the base bottom portion 2a of the base 2, and the connection terminal 4 and the power storage element 6 are connected to each other via the wiring 3. It is electrically connected. In addition to the structure in which the wiring 3 penetrates the base bottom portion 2a in this way, as shown in FIG. 2B, the side wiring 3a extending from the connection terminal 4 and formed on the side surface of the base 2 and the side wiring thereof. It is composed of an interlayer wiring 3b formed between a plurality of plate-shaped sheets connected to 3a and constituting the base 2, and a via wiring 3c formed through the base bottom surface 2c to the position of the interlayer wiring 3b. It can be a structure. Further, one of the wiring 3 on the positive electrode side and the negative electrode side is a through wiring as shown in FIG. 2A, and the other is a wiring structure in which a via wiring and an interlayer wiring are combined and routed as shown in FIG. 2B. May be.

Examples of the constituent material of the base 2 include ceramics containing at least one selected from the group consisting of alumina, silicon nitride, zirconia, silicon carbide, aluminum nitride, mullite, and composite materials thereof. Not limited to this. Soda lime glass and heat-resistant glass can also be used. Since a long piece of glass can be used as the material, in the case of a small package, a large number of pieces can be set for one piece of glass, and cost reduction of the base member can be expected.

The base 2 of the present embodiment is, for example, after the ceramic green sheet corresponding to the base bottom portion 2a punched out in a rectangular shape is bonded to the ceramic green sheet corresponding to the base peripheral wall portion 2b punched out in a rectangular frame shape. It is formed by firing. A through hole can be formed by punching a hole in the ceramic green sheet corresponding to the base bottom portion 2a in advance, and the via wiring 3c can be formed by using the through hole.

In the present embodiment, a plurality of wirings 3 as through wirings as shown in FIG. 2A and a plurality of via wirings 3c as shown in FIG. 2B are formed on each of the positive electrode side and the negative electrode side. Can be done. As a result, the wiring resistance can be reduced as compared with the case where a single wiring is used. In addition, even if one of the plurality of wires is broken due to a defect during manufacturing or corrosion during use, the other wiring can be used to make an electrical connection between the power storage element 6 and the connection terminal 4. Can be maintained. In particular, in the wiring structure as shown in FIG. 2B, not only the via wiring 3c but also the interlayer wiring 3b may be included as a plurality of wiring structures branched from the side wiring 3a, or may be branched from the connection terminal 4. A plurality of wirings 3 composed of a pair of the side wiring 3a, the interlayer wiring 3b, and the via wiring 3c may be formed.

Further, in the present embodiment, the wiring 3 and the connection terminal 4 are made of a refractory metal such as tungsten or molybdenum. Specifically, a paste obtained by mixing these refractory metal powders and a resin is filled in the through holes provided in the ceramic green sheet constituting the base bottom portion 2a of the base 2, thereby forming the via wiring 3c. Material can be embedded. Further, by applying the paste to the surface of the ceramic green sheet, it is possible to form a material to be the side wiring 3a, the interlayer wiring 3b, and the connection terminal 4. Then, the ceramics of the base 2 and the wiring 3 and the connection terminal 4 are integrally formed by laminating and firing a plurality of these ceramic green sheets in which the paste is incorporated.

The material constituting the wiring 3 and the connection terminal 4 may be a carbon material, nickel, gold, or a mixture of these composite materials, in addition to a refractory metal such as tungsten or molybdenum. In particular, by using a refractory metal such as tungsten or molybdenum as the material constituting the wiring 3 and the connection terminal 4, the base 2 integrally formed with the ceramics can be obtained. Further, by forming a material having good solder wettability on the surfaces of the wiring 3 and the connection terminal 4, it is possible to maintain good bonding with the circuit board of the mounted device. This material can be, for example, a plating layer, but in particular, if it is a two-layer plating layer composed of a nickel plating layer and a gold plating layer on the surface thereof, it is formed together with the pad film 5 described later. preferable.

(Pad membrane)
A pad film 5 composed of a nickel-plated layer and a gold-plated layer formed on the nickel-plated layer is formed on the exposed surface of the wiring 3 and the connection terminal 4 formed on the base 2 from the base 2. In particular, since the pad film 5 is formed on the exposed surface of the connection terminal 4 from the base 2, it is possible to maintain good bonding with the circuit board of the mounted device by soldering or the like.

Further, in the present embodiment, the pad film 5 is continuously formed not only on the exposed surface of the wiring 3 on the bottom surface 2c of the base but also around the exposed surface of the wiring 3. Since the pad film 5 is formed not only on the exposed surface of the wiring 3 but also around the exposed surface of the wiring 3, the protection of the wiring 3 by the pad film 5 can be further ensured. In addition to this, since the pad film 5 is formed on the bottom surface 2c of the base in addition to the position of the wiring 3, a sufficient joint area between the pad film 5 and the cell lead 8 can be secured.

The positional relationship between the region where the pad film 5 is formed on the bottom surface 2c of the base and the exposed surface of the wiring 3 will be described with reference to FIG. In the present embodiment, the position of the wiring 3 may be formed at any position as long as it is in the region where the pad film 5 is formed, but in particular, it is formed at the end of the formation region of the pad film 5. Is preferable. When a plurality of wirings 3 are formed, it is preferable that the positions of the wirings 3 are concentrated at the end of the formation region of the pad film 5.
With such a positional relationship, it is possible to secure a wide region of the pad film 5 forming region where the wiring 3 is not formed. When the pad film 5 and the cell lead 8 are bonded by ultrasonic welding or the like in this region, damage to the pad film 5 and the wiring 3 can be suppressed.

As one example of the present embodiment, the pad film 5 may have a two-layer structure including a nickel-plated layer and a gold-plated layer formed on the nickel-plated layer. When the wiring 3 and the connection terminal 4 are made of tungsten, molybdenum, etc., in order to maintain good bonding with the circuit board of the mounted equipment by soldering, etc., a material with good solder wettability and excellent conductivity is used. It is necessary to form on these exposed surfaces. In the case of a two-layer structure consisting of a nickel-plated layer and a gold-plated layer, in addition to forming a plating layer on the exposed surface of the connection terminal 4 outside the container, a plating layer is also formed on the exposed surface of the wiring 3 inside the container. Can be done.

Further, in the present embodiment, the plating layer is formed not only on the exposed surface of the wiring 3 on the bottom surface 2c of the base but also on the periphery thereof, so that the plating layer can function as the pad film 5. As described above, by forming the plating layer as the pad film 5, the pad film can be formed more easily than the film formation by thin film deposition or sputtering, and the pad film can be formed at a lower cost than the conventional one. In this case, even if the covering portion 11 described later is formed, the electrochemical cell can be manufactured at a sufficiently low cost.

The pad film 5 composed of such a plating layer is composed of two layers, a nickel plating layer and a gold plating layer, and further, within a range permitted from the viewpoint of cost, other plating layers such as copper plating and gold alloy plating. Can be added. For example, after forming copper plating on the wiring 3, a nickel plating layer and a gold plating layer can be sequentially formed.

The total thickness of the plating layer is preferably 1 μm or more, more preferably 1 μm or more so as to enable bonding with the lead, but 20 μm so as not to reduce the thickness of the power storage element 6 in consideration of the internal volume of the container. The following is preferable. Further, the upper limit of the total thickness of the plating layer is set in consideration of cost. In particular, when aluminum is used as the material of the cell lead 8, the gold-plated layer having good bondability preferably has a predetermined thickness, and may be 0.1 μm or more, preferably 1 μm or more. On the other hand, from the viewpoint of cost, the upper limit of the thickness of the gold-plated layer is preferably 10 μm, particularly preferably 5 μm, but is not limited to this. As an example of the above plating thickness, the nickel plating layer can be 5 μm and the gold plating layer can be 1 μm, but the present invention is not limited to this.

As another example of this embodiment, aluminum, which is a valve metal, can be used as the pad membrane 5. As will be described later, when aluminum is used as the material of the cell lead 8, the pad film 5 and the cell lead 8 are bonded by ultrasonic welding, resistance welding or the like to maintain good bonding strength and to maintain the reliability of the electrochemical cell 1. Sex can be ensured. Further, by covering the wiring 3 with the aluminum pad film 5 made of the valve metal, the wiring 3 can be protected from contact with the electrolyte.

In the present embodiment, as the aluminum, various aluminum alloys such as Al—Cu based alloys, Al—Mn based alloys, and Al—Mg based alloys can be used in addition to the pure aluminum type defined by JIS.

The aluminum pad film 5 is formed on the bottom surface 2c of the base by vapor deposition, sputtering, or the like after the base 2 provided with the wiring 3 and the connection terminal 4 is formed. At this time, depending on the film forming conditions, the thickness of the film may be reduced or defects such as pinholes may occur. Therefore, in order for the aluminum pad film 5 formed by the above method to sufficiently cover the wiring 3 by itself, a film thickness of 15 μm or more is usually required.

On the other hand, in the present embodiment, the wiring 3 can be sufficiently protected from the electrolyte by combining with the covering portion 11 described later, so that the thickness of the aluminum pad film 5 is bonded to the cell lead 8. It is sufficient if it is the minimum necessary to secure. The specific film thickness may be, for example, 1 μm or more, preferably 2.5 μm or more.

Further, the upper limit of the film thickness of the pad film 5 is not particularly set from the viewpoint of ensuring the bonding with the cell lead 8, but considering the cost of the manufacturing process such as vapor deposition and sputtering, 100 μm or less is preferable, and 50 μm or less is more preferable. .. In particular, from the viewpoint of producing an electrochemical cell in combination with the covering portion 11 at low cost in the present invention, the thickness of the aluminum pad film 5 is preferably less than 15 μm, more preferably less than 10 μm. Since sufficient corrosion resistance can be ensured by combining the pad film 5 made of aluminum having such a thickness and the covering portion 11 described later, an electrochemical cell that is cheaper than the conventional configuration and has excellent reliability. Can be.

Further, as the aluminum pad film 5 that protects the exposed surface of the wiring 3, an aluminum film by an electroplating method using a plating solution composed of dimethyl sulfone and aluminum chloride can also be formed. Even in this case, the surface of the connection terminal 4 needs to be a nickel and gold plating film for soldering to the circuit board of the mounted device. Although the cost is increased in this respect, it is a preferable mode because it has a merit of improving the corrosion resistance of the wiring 3.

As the material of the pad film 5, aluminum may be simply formed by vapor deposition, sputtering, or the like after the above-mentioned plating layer is formed. This is preferable because it is possible to further secure the bonding between the pad film 5 and the cell lead 8.

(Power storage element)
In the present embodiment, the power storage element 6 insulates a pair of positive and negative electrode sheets in which an aluminum foil or a copper foil having a thickness of 5 μm to 50 μm is used as a current collector and an active material is supported on the surface thereof by coating or an adhesive method. It is integrated by means of winding, laminating, folding, etc., with a separator made of objects sandwiched between them.

As the material of the active material, for example, when the electrochemical cell 1 is an electric double layer capacitor, a carbon material such as activated carbon can be used. In the case of a lithium ion secondary battery, examples of the positive electrode active material include lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), lithium manganate (LiMn ₂ O ₄ ), and lithium iron phosphate (LiMn 2 O 4). Compounds such as LiFePO ₄ ) can be used. As the negative electrode active material of the lithium ion secondary battery, for example, a carbon material such as graphite or coke, or a compound such as silicon or an oxide thereof can be used.

These active materials are mixed with a conductive auxiliary agent such as carbon, a binder made of resin or the like, a dispersant, and the like, and are applied to one side or both sides of the current collector. As the coating method, for example, roller coating, screen coating, doctor blade method and the like can be used. Then, the current collector coated with the active material can be processed into an electrode sheet by drying, pressing, or the like.

The separator regulates the direct contact between the positive electrode and the negative electrode, and an insulating film having a large ion transmittance and a predetermined mechanical strength is used. For example, in an environment where heat resistance is required, resins such as polytetrafluoroethylene, polyphenylene sulfide, polyphthalamide, polyethylene terephthalate, polybutylene terephthalate, polyamide, and polyimide can be used in addition to glass fiber. The pore diameter and thickness of the separator are not particularly limited, but are determined based on the current value of the equipment used and the internal resistance of the electrochemical cell 1. It is also possible to use a porous body of ceramics as a separator.

(Electrolytes)
In the present embodiment, the electrolyte is preferably in the form of a liquid or gel used in known electric double layer capacitors and non-aqueous electrolyte secondary batteries.

Organic solvents used for liquid and gel electrolytes include acetonitrile (AN), diethyl ether (DEE), diethyl carbonate (DEC), dimethylcarbonate (DMC), 1,2-dimethoxyethane (DME), There are tetrahydrofuran (THF), propylene carbonate (PC), ethylene carbonate (EC), γ-butyrolactone (γBL), sulfolane, propionic acid ester, chain sulfone and the like, and these can be used alone or in combination.

In particular, a solvent containing propionic acid ester or chain sulfone as a sub-solvent in a high boiling point main solvent such as propylene carbonate (PC), ethylene carbonate (EC), γ-butyrolactone (γBL), and sulfolane is suitable. However, it is not limited to these.

The materials contained in the liquid and gel electrolyte 7 include (C ₂ H ₅ ) ₄ PBF ₄ , (C ₃ H ₇ ) ₄ PBF ₄ , (CH ₃ ) (C ₂ H ₅ ) ₃ NBF ₄ , ( C ₂ H ₅ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ PPF ₆ , (C ₂ H ₅ ) ₄ PCF ₃ SO ₄ , (C ₂ H ₅ ) ₄ NPF ₆ , Lithium perchlorate (LiClO ₄ ), Lithium hexafluorophosphate (LiPF ₆ ), lithium borofluoride (LiBF ₄ ), lithium hexafluoroarsenide (LiAsF ₆ ), lithium trifluoromethsulfonate (LiCF ₃ SO ₃ ), bistrifluoromethylsulfonylimide lithium [LiN] (CF ₃ SO ₂ ) ₂ ], thiosian salt, aluminum fluoride salt, lithium salt and the like can be used. Examples of the supporting salt of the liquid electrolyte 7 include a quaternary ammonium salt and a quaternary phosphonium salt. Examples of the quaternary ammonium salt include a compound having only an adipose chain, an alicyclic compound having an adipose chain and an alicyclic, and a spiro compound having only an adipose ring. In particular, the spiro compound 5-azoniaspiro [4,4] nonane tetrafluoroborate (spiro- (1,1') -bipyrrolidinium: SBP-BF ₄ ) is suitable for use because of its high electrical conductivity. It is not limited to.

The gel-like electrolyte is a polymer gel impregnated with a liquid electrolyte. Suitable polymer gels include polyethylene oxide, polymethyl methacrylate, and polyvinylidene fluoride, but the polymer gel is not limited thereto.

Further, normal temperature molten salts such as pyridine-based, alicyclic amine-based, aliphatic amine-based, imidazolium-based ionic liquids, and amidine-based may be used.
Further, instead of using the above-mentioned electrolyte and separator, the power storage element 6 may be configured by integrating the electrode sheet with the solid electrolyte.

(Cell lead)
In the present embodiment, the cell lead 8 is a terminal for extracting electric power from the power storage element 6. The cell lead 8 can be an extension portion obtained by extending the current collector itself, or an extension portion formed by mechanically connecting another member having a ribbon shape or a wire shape to the current collector. The bonding portion 8a, which is a part of the cell lead 8, is bonded to the pad film 5 described above by welding such as ultrasonic welding.

As the material of the cell lead 8, various metals such as aluminum and nickel can be used.
In particular, when the pad film 5 is made of aluminum, a metal material having a melting point close to that of aluminum and having excellent corrosion resistance is required so that the pad film 5 can be firmly connected to the pad film 5 by welding. In particular, pure aluminum and various aluminum alloys are preferable because even a pad film 5 having a simple coating film is firmly connected to the cell lead 8. Further, if the cell lead 8 is an extension of the current collector constituting the above-mentioned power storage element 6, the material of the current collector, such as aluminum or copper, is the material of the cell lead 8.

Further, the cell lead 8 provides a space for arranging a jig such as a welding tip for welding with the pad film 5 and applying a covering portion 11 described later to protect the pad film 5 and the joint portion 8a. In order to secure it, it is desirable to secure a predetermined length. Specifically, it is preferable that the length of the cell lead 8 is such that the power storage element 6 can be placed outside the base 2 after welding the pad film 5 and the cell lead 8. On the other hand, if the cell lead 8 is made excessively long, the internal resistance increases. Therefore, it is preferable to adjust the length appropriately according to the size of the base 2.

The power storage element 6 is housed in the base 2 after the pad film 5 and the cell lead 8 are welded to protect the welded portion with a covering portion. At this time, the cell lead 8 is folded inside the base 2. Further, when folding the cell lead 8, care must be taken so that the cell lead 8 does not come into contact with the seal ring 9 and the power storage element 6 is not short-circuited.

The pad film 5 and the cell lead 8 can be bonded by local welding such as ultrasonic welding, beam welding, and resistance welding. Of these, ultrasonic welding is a more preferable embodiment because the influence of welding heat can be minimized.

(Cover)
In the present embodiment, the covering portion 11 is formed so as to cover the joint portion 13 of the pad film 5 and the cell lead 8 with the pad film 5. The covering portion 11 prevents the pad film 5 and the wiring 3 under the pad film 5 from coming into contact with the electrolyte, and can prevent corrosion of the wiring.

In order to protect the pad film 5, the covering portion 11 has a covering property for the pad film 5, prevents the penetration of electrolytes, and has heat resistance during reflow soldering and use, and electrolytic corrosion. It is necessary to have corrosion resistance to the oxidizing environment.

As the material constituting such a covering portion 11, for example, various insulating resins can be used. Of these, epoxy resins, phenol resins, and thermosetting resins such as polyimide are particularly preferably used. In addition to having high heat resistance due to the high glass transition temperature and softening point, these resins can sufficiently cover the pad film 5 and the wiring 3 under it, effectively preventing contact between these members and the electrolyte. can do. In particular, the polyimide resin has not only heat resistance but also corrosion resistance against anode corrosion, and sufficiently protects the pad film 5 without using additives such as an inorganic compound filler as described later. It is a particularly preferable material because it can be used.

In the present embodiment, in addition to the above-mentioned insulating resin, a thermosetting resin to which a filler of particles made of an inorganic compound having insulating properties, heat resistance, and corrosion resistance is added is particularly preferably used for the covering portion 11. Be done. By using such a thermosetting resin, the heat resistance of the coating portion 11 can be further improved and the coating portion 11 can be formed into a chemically stable coating, so that a high thermal environment during reflow soldering or use can be obtained. The durability of the covering portion 11 can also be maintained. On the other hand, when the coating portion 11 is formed only with the inorganic compounds constituting the filler, for example, glass coating, the coating is broken due to the corrosive environment during use, and sufficient corrosion resistance cannot be obtained. It ends up.

As the inorganic compound as the filler, various metal oxide particles such as silica, alumina, and titania can be used. In addition, minerals such as silicates, compounds such as sulfates, and the like can be mentioned. In particular, when silica is used as a filler for inorganic particles, it has extremely high heat resistance and is chemically stable against various corrosive environments, so that the heat resistance and durability of the coating portion 11 can be further improved. can.

As an example of the configuration of such a covering portion 11, various synthetic resin paints can be used. Synthetic resin paints include phenol resin, urea resin, melamine resin, alkyd resin, vinyl resin, acrylic resin, acrylic silicon, modified silicon resin, epoxy resin, silicon resin, fluororesin, phthalic acid resin, unsaturated polyester resin, and polyurethane resin. , Etc., are added to various synthetic resins such as, and pigments composed of various compounds including the above-mentioned inorganic compounds, and are dissolved in an organic solvent. The pigments are preferably all inorganic compounds, but may contain a very small amount of carbon black or the like for color development as long as they do not affect the insulating properties of the coating portion 11. By using such a synthetic resin paint, the coating portion 11 can be further reduced in cost.

In this way, by forming the insulating coating portion 11, the pad film 5 having positive and negative potentials can be formed across the pad films 5 on the bottom surface 2c of the base without short-circuiting.

As for the configuration of the coating portion 11 in the present embodiment, for example, in the combination of the filler of the resin and the inorganic compound, the filler is preferably contained in the coating portion 11 in an amount of 1 to 90% by weight, preferably 10 to 80% by weight. It is more preferable to do so. If the amount of the filler is too small, the covering portion 11 cannot obtain sufficient heat resistance and durability. On the other hand, if the amount of filler is too large, the covering portion 11 is cracked due to electrolytic corrosion, and the wiring 3 cannot be sufficiently protected.

On the other hand, as described above, when the polyimide resin is used as the resin, it is preferable to use the covering portion 11 alone, but it is considered that the same effect can be obtained even if the filler in the above-mentioned ratio is contained.

Further, when forming the covering portion 11, a paint in which these materials are mixed with a solvent is used in order to apply the precursor and the filler before curing of the resin described above. Further, for example, when the resin is a thermosetting resin such as an epoxy resin, a mixture of two liquids of a main agent and a curing agent is used.

Here, the thickness at which the covering portion 11 is formed will be described in detail with reference to FIG.
FIG. 2 shows an AA cross section of the electrochemical cell 1 in the present embodiment, and describes an outline of the present invention including the configuration of the wiring 3. On the other hand, FIG. 4 shows a BB cross section shifted from the AA cross section in order to explain the positional relationship between the heights of the connecting portion 13 between the cell lead 8 and the pad film 5 and the covering portion 11. be. Here, in order to understand the positional relationship between the pad film 5 and the wiring 3, the wiring 3 at the position of the AA cross section is represented by a dotted line. The structure of the wiring 3 corresponds to FIG. 2A, but the same applies to the wiring 3 corresponding to FIG. 2B, and the structure is limited to the structure inside the base bottom 2a of the wiring 3. Not done.

Since the covering portion 11 needs to cover the pad film 5 and the joint portion 13 between the cell lead 8 and the pad film 5 as described above, the covering portion 11 and the pad film 5 are at least as shown in FIG. 4A. It is preferably formed according to the thickness of the overlapping cell leads 8. Specifically, the covering portion 11 may be formed at the same height as or thicker than the thickness of the cell lead 8 at this position. By forming in this way, it is possible to sufficiently secure the covering property of the covering portion 11 with respect to the pad film 5.

Further, as shown in FIG. 4B, the covering portion 11 may be formed up to a position below the power storage element 6. On the other hand, if the covering portion 11 is made too thick, the accommodation space in the base 2 is limited, and the power storage element 6 receives an unnecessarily compressive force in the base 2, which may cause a short circuit.

Considering the corrosion resistance of the material of the covering portion 11 in addition to the positional relationship between the covering portion 11 and other members as described above, the thickness of the covering portion 11 is more preferably 200 μm or more and 300 μm or less.

(Seal ring)
As shown in FIG. 2A, the seal ring 9 has a square frame-shaped cross section that matches the shape of the upper end surface of the base peripheral wall portion 2b of the base 2, and is waxed on the upper end surface of the base peripheral wall portion 2b. It is joined via a material. For the seal ring 9, a material having a coefficient of thermal expansion close to that of ceramic, for example, Kovar (trade name of Westinghouse Electric Corporation), which is an iron-cobalt-nickel alloy, can be used. The brazing material is formed of an Ag—Cu alloy, an Au—Cu alloy, or the like.

(Sealing plate)
As shown in FIG. 1, the sealing plate 10 is joined to the upper surface of the seal ring 9 and seals the base 2. As the sealing plate 10, a nickel-plated alloy such as Kovar or 42alloy, which has a coefficient of thermal expansion close to that of ceramic, is used. More specifically, a thin plate made of Kovar having a thickness of about 0.1 mm to 0.2 mm and having a surface surface coated with electrolytic nickel plating or electroless nickel plating having a thickness of about 2 μm to 4 μm is used.

The sealing plate 10 using such a material can be welded to the seal ring 9 by, for example, resistance seam welding, laser seam welding, or the like, and the airtightness inside the base 2 in the closed state can be improved. The base 2 is airtightly closed by the sealing plate 10.

In the resistance seam welding used as a method of welding the sealing plate 10 and the sealing ring 9, after the sealing plate 10 is brought into contact with the sealing ring 9, it faces two points at substantially the center of the long side of the sealing plate 10. Temporary welding (spot welding) of the sealing plate 10 is performed by arranging a trapezoidal roller electrode and passing a low voltage and a large current for a short time. In this way, the sealing plate 10 is temporarily fixed, and the position does not shift due to vibration or the like during the welding operation.

Subsequently, for example, the base 2 and the sealing plate 10 are moved and welded so that the long side is traced by the roller electrode from the end of the long side. Next, the base 2 and the sealing plate 10 are rotated 90 degrees, and the short sides are similarly welded. In this way, welding is performed over the entire circumference of the sealing plate 10. In both the above-mentioned temporary fixing and the present resistance seam welding, diffusion of gold and nickel occurs at the interface between the sealing plate 10 and the seal ring 9, and an airtight and strong diffusion bonding layer is formed. As a result, the sealing plate 10 seals the base 2 with high airtightness.

Welding of the sealing plate 10 and the seal ring 9 is also possible by using scanning irradiation of a laser. After performing the temporary welding in the same manner as described above, the laser is scanned and irradiated so as to go around the sealing plate 10. As a result, a diffusion bonding layer is formed at the interface between the sealing plate 10 and the sealing ring 9. In this case, it is also possible to lower the melting temperature to the temperature of the brazing material by attaching a brazing material sheet made of silver and copper to the surface of the sealing plate 10 on the joining side.

When the electrolyte is composed of a liquid solvent or supporting salt at room temperature and the step of filling the electrolyte 7 before sealing the sealing plate 10 is adopted, the liquid exists at the interface between the sealing plate 10 and the seal ring 9. There can be a place to do it. Even in such a case, joining using seam welding is possible.
Seam welding may use roller electrodes or laser scanning irradiation.

It is considered that the airtight welding is possible even if the liquid is present at the interface because the liquid existing at the interface evaporates and scatters because the temperature in the vicinity rises sharply at the time of welding. The upper end surface of the base 2 and the sealing plate 10 may be joined to each other via a brazing material without using the seal ring 9.

(Example)
Next, Examples and Comparative Examples will be shown, and the present invention will be described in more detail. The scope of the present invention is not limited by the present embodiment, and the non-aqueous electrolyte secondary battery according to the present invention can be appropriately modified and implemented without changing the gist of the present invention. be.

[Example 1]
The concave base 2 and the sealing plate 10 shown in FIGS. 1 and 2 (a) were prepared. As the base 2, a box-shaped container made of alumina having a long side of 10 mm, a short side of 8 mm, a height of 1.8 mm, and a thickness of a peripheral wall portion and a bottom portion of 0.38 mm was used.

The base 2 was formed by sticking a rectangular frame-shaped ceramic green sheet constituting the base peripheral wall portion 2b to a plate-shaped ceramic green sheet constituting the base bottom portion 2a and firing at about 1500 ° C. The wiring 3 is a via wiring in which a via hole formed by punching so as to penetrate the top and bottom of the ceramic green sheet corresponding to the base bottom 2a is filled with a tungsten paste composed of tungsten powder, a resin binder, and a solvent.

At this time, the diameter of the via hole was set to 0.2 mm, and four via holes were formed on the positive electrode side and the negative electrode side. Further, a tungsten paste corresponding to the connection terminal 4 connected to the wiring 3 was applied to the portion of the base bottom 2a on the base lower surface 2d by screen printing. The tungsten paste corresponding to the wiring 3 and the connection terminal 4 was fired together with the ceramic green sheet to prepare a base 2 integrated with the wiring 3 and the connection terminal 4.

Next, a seal ring 9 was formed on the upper end of the base peripheral wall portion 2b of the fired base 2 using silver wax.

Then, electrolytic nickel plating and electrolytic gold plating are sequentially applied to the connection terminal 4 of the base 2, the exposed portion of the wiring 3 arranged on the bottom surface 2c of the base, and the bottom surface of the base around the wiring 3 to form the pad film 5. did. The thickness of the pad film 5 at this time was 5 μm for the nickel-plated layer and 1 μm for the gold-plated layer. Further, the pad film 5 formed on the bottom surface 2c of the base has a long side of 3 mm and a short side of 2.4 mm on each of the positive electrode side and the negative electrode side.

Next, the power storage element 6 was prepared as follows. First, on a current collector made of aluminum foil having a thickness of 20 μm, the thickness is composed of 85% by weight of activated carbon, 8% by weight of a conductive aid made of Ketjen black, and 7% by weight of a binder made of polytetrafluoroethylene. A sheet electrode having a thickness of 30 μm coated on one side was prepared. An aluminum ribbon having a thickness of 80 μm, a width of 1.5 mm, and a length of 4 mm was attached to the end of the sheet electrode by ultrasonic welding to form a cell lead 8. Then, a separator made of a polytetrafluoroethylene sheet was sandwiched between a pair of positive electrode and negative electrode sheet electrodes to which the cell lead 8 was attached, and then these were wound around to form a power storage element 6.

Next, the pad film 5 formed on the base bottom surface 2c of the base 2 and the cell lead 8 extending from the power storage element 6 were bonded by ultrasonic welding. Then, the paste-like covering portion 11 was applied using a dispenser so as to cover the pad film 5 including the joining portion. Further, the base 2 to which the power storage element 6 was attached was heated to the curing temperature of each material constituting the coating portion 11 to cure the coating portion 11.

The covering portion 11 contains 20 to 30% by weight of an epoxy resin as a main component. In addition, it contains 10 to 20% of a filler of inorganic particles made of silica. The rest is an inorganic compound pigment.

After the covering portion 11 was formed in this way, the cell lead 8 was folded so that the power storage element 6 was housed in the base 2. At this time, in order to prevent an internal short circuit, the cell lead 8 is arranged so that the cell lead 8 does not come into contact with the seal ring 9. Then, after injecting the liquid electrolyte 7 into the inside of the base 2, vacuum defoaming was performed for 1 minute. As the electrolyte 7, SBP-BF ₄ was used as a supporting salt, and a mixed solution of PC, EC and DMC was mixed as a solvent at the following ratios and used as a mixed electrolyte. The mixing ratio is the relationship of solvent: supporting salt = 75% by mass: 25% by mass with respect to the total mass of the electrolyte 7, and the ratio of PC: EC: DMC = 39% by mass: 32% by mass: 29% by mass in the solvent. The electrolyte mixed in was used.

Next, the pressure is returned to atmospheric pressure, the sealing plate 10 is brought into contact with the seal ring 9 under a nitrogen atmosphere, temporary welding is performed at two points on the long side, and then the long side and the short side are continuously connected in this order. Resistance seam welding was performed to airtightly seal the base 2. In this way, the electrochemical cell 1 of this example was produced.

[Examples 2 to 6]
An electrochemical cell 1 was produced in the same manner as in Example 1 except that the resin, the type of filler, and the compounding ratio of the covering portion 11 were adjusted as shown in Table 1 described later.

[Comparative Example 1]
The electrochemical cell 1 was produced in the same manner as in Example 1 except that the covering portion 11 was not provided.

[Comparative Example 2]
An electrochemical cell 1 was produced in the same manner as in Example 1 except that a silica film was formed by using a glass coating agent on the covering portion 11.

(evaluation)
The obtained electrochemical cell was evaluated as follows.
(Evaluation of wiring protection function)
Prior to the cell evaluation, in order to evaluate the wiring protection function of the covering portion 11, the following evaluation was performed using a test piece.

First, a ceramic substrate on which a tungsten thin film having a thickness of 1 μm was formed was prepared by applying the above-mentioned tungsten paste on a plate-shaped ceramic green sheet and firing it. Nickel plating and gold plating were sequentially applied to this substrate to form a nickel plating layer having a thickness of 5 μm and a gold plating layer having a thickness of 1 μm. Then, a test piece was produced by forming a covering portion of the material shown in Table 1 described later on the plating layer.

This test piece and a Koval plate made of the same material as the sealing plate were sandwiched between the polytetrafluoroethylene separators impregnated with the electrolyte having the above composition so that the plating layers faced each other. Then, a positive potential was applied to the wiring portion of the test piece and a negative potential was applied to the Kovar plate so that the potential difference was 2.5 V. After 20 days of applying the voltage in this way, the test piece was visually observed and observed with a stereomicroscope to check for the presence or absence of dissolution of the tungsten thin film.

(Evaluation of storage characteristics)
The electrochemical cell 1 provided with the covering portion 11 of each Example and Comparative Example produced by the above process was passed through a heat treatment furnace for reflow soldering so as to hold the entire cell at 260 ° C. for 5 seconds. After that, the internal resistance (Ω) was measured (initial resistance). This internal resistance was determined by measuring the impedance at 1 kHz AC.
Then, this cell was charged to 2.5 V in an atmosphere of 70 ° C., stored for 5 days and 20 days, and then the internal resistance was measured in the same manner (resistance after 5 days and 20 days).

(Evaluation results)
Table 1 shows the contents of the main components and fillers of the covering portion 11 of each Example and Comparative Example, and the evaluation results. As the main component of each of the examples in Table 1, a synthetic resin mixed with a thermosetting resin or the like is used in addition to an epoxy resin and a polyimide resin. Further, as the main raw material of the filler, silica having a blending ratio shown in Table 1 is mixed in the coating portion 11. In addition to these resins and silica, pigments made of various inorganic compounds are mixed in the coating portion 11 of each example.

In Table 1, since the covering portion is not formed in Comparative Example 1, the compounding ratio of the main component, the type of the filler, and the compounding ratio are indicated by "-". Further, in Example 6 and Comparative Example 2, since the coating portion does not contain a filler, the type and blending ratio of the filler are indicated by “−”.

In addition, in the "Wiring protection function" column of "Evaluation" in Table 1, as described later, when an abnormality such as the disappearance of tungsten is found in the evaluation result, it is indicated as "x", and the others are indicated as "○". is doing. Then, regarding the "preservation characteristics", the conditions under which the evaluation was not performed are described as "-".

In the wiring protection function evaluation, no change was observed in the appearance of the test piece after the evaluation test in Examples 1 to 6. On the other hand, in Comparative Examples 1 and 2, the tungsten thin film formed on the test piece was dissolved and partially disappeared after the evaluation test. In particular, the silica film of Comparative Example 2 cracked after the evaluation test, and the electrolyte reached the tungsten thin film through the cracks. Therefore, in Comparative Example 2, the storage characteristic evaluation described later was not performed.

In the storage characterization, the resistance after 5 days was 1.3 to 1.5 times the initial resistance in each example, whereas it was 2.6 times the initial resistance in Comparative Example 1. In addition, the resistance after 20 days was 1.6 to 1.9 times the initial resistance in each example, which was a level at which long-term reliability was sufficiently maintained, whereas in Comparative Example 1, it was 16 times the initial resistance. Also rose. In Examples 3, 4 and 6, the storage characteristics were not evaluated because the heat resistance of the covering portion 11 by the reflow heat treatment was not sufficient.

Moreover, when the cell after the preservation characteristic evaluation was disassembled and investigated, the pad film 5 was cracked in Comparative Example 1. As a result, it is considered that the electrolyte reaches the wiring 3 made of tungsten in the lower layer and the wiring resistance is increased. On the other hand, in each example, such a crack of the pad film 5 was not observed.

As described above, it has been found that by forming the covering portion 11 having sufficient corrosion resistance, long-term reliability that can withstand actual use can be obtained even in a configuration in which cell leads are bonded to the pad film 5. In particular, when the coating portion 11 has sufficient heat resistance such as a polyimide resin, or when it is an insulating resin containing an inorganic particle filler such as silica, electrochemical is further excellent in long-term reliability. It turns out that it can be cell 1.

(Evaluation of bonding strength of Al pad film and cell lead)
Next, aluminum was used as the pad film 5 in the present invention, and the bonding strength with the cell lead 8 when the thickness thereof was variously changed was investigated.

Specifically, first, an aluminum film having the thickness shown in Table 2 was formed by sputtering on a square ceramic substrate having a side of 10 mm to form a pad film 5. Then, an aluminum ribbon having a thickness of 80 μm, a width of 2 mm, and a length of 50 mm, which imitates a cell lead 8, was bonded to the pad film 5 by ultrasonic welding. This aluminum ribbon was attached to a tensile strength tester, and a tensile test was carried out for each thickness condition at n = 5, and the average and standard deviation of the test forces were obtained. The results are shown in Table 2.

As shown in Table 2, the pad film 5 and the cell lead are formed even when the thickness is 1 μm or 2.5 μm, as in the case of the conventional aluminum pad film 5 having a typical thickness of 30 μm or the lower limit of 10 μm. It was found that sufficient bonding with 8 could be secured. In particular, it was found that in the case of a thickness of 2.5 μm, the variation is the same as in the case of a thicker thickness, and stable bonding can be maintained.

(Corrosion resistance of Al pad film)
Further, the corrosion resistance due to the difference in the thickness of the pad film 5 was evaluated. Similar to the above-mentioned bonding durability test, a tungsten pattern having a thickness of 1 μm and an outer diameter of 3 mm was formed by sputtering on a square ceramic substrate having a side of 10 mm. Then, an aluminum film having each film thickness in Table 2 was formed by sputtering so as to cover the tungsten pattern from above.

A simulated cell was produced by facing the test piece thus formed and a metal plate made of Kovar via a porous separator made of polytetrafluoroethylene having a thickness of 20 μm. This cell was immersed in an electrolyte in which the supporting salt was SBP-BF4 and the solvent was a mixed solution of PC, EC and DMC. The mixing ratio is the relationship of solvent: supporting salt = 75% by mass: 25% by mass with respect to the total mass of the electrolyte, and the ratio of PC: EC: DMC = 39% by mass: 32% by mass: 29% by mass in the solvent. A mixed electrolyte was used. Then, in an environment at room temperature, the test piece was set to a positive potential, the metal plate was connected to a power source so as to have a negative potential, a voltage of 3.3 V was continuously applied for 5 days, and the presence or absence of corrosion of the tungsten pattern was examined. ..

As shown in Table 2, no corrosion of the tungsten pattern was observed under the conditions where the thickness of the pad film 5 was 10 μm and 30 μm, but the tungsten pattern was corroded and a part was dissolved under the conditions of 1 μm and 2.5 μm.

As described above, it was found that in the case of the aluminum pad film 5, the bonding with the cell lead 8 can be maintained even with a thickness smaller than 10 μm, but the corrosion resistance cannot be maintained. Similar to the pad film 5 made of a plating layer, the above-mentioned covering portion 11 is combined with the aluminum pad film 5 to impart corrosion resistance to the electrochemical cell 1 having excellent long-term reliability. Can be.

1 ... Electrochemical cell 2 ... Base 2a ... Base bottom 2b ... Base peripheral wall 2c ... Base bottom 2d ... Base bottom 3 ... Wiring 3a ... Side wiring 3b ... Interlayer wiring 3c ... Via wiring 4 ... Connection terminal 5 ... Pad film 6 ... Power storage element 7 ... Electrolyte 8 ... Cell lead 9 ... Seal ring 10 ... Sealing plate 11 ... Cover 12 ... Storage container 13 ... Joint

Claims (1)

A method for manufacturing an electrochemical cell in which a power storage element is stored in a storage container including a base and a sealing plate.
Forming a pad layer on the base connection terminal and the wiring made of insulating material is integrally formed,
A step of connecting the cell read of the electric storage element to the pad layer,
A step of coating the pad film to which the cell leads are connected with an insulating coating portion, and
The step of sealing the base with the sealing plate and
A method for producing an electrochemical cell, which comprises.

Images