JP6705702B2 - Electrochemical cell - Google Patents

Description

The present invention relates to surface mountable electrochemical cells.

BACKGROUND ART Electrochemical cells have hitherto been used as a backup power source for semiconductor memories or a backup power source for electronic devices such as microcomputers and IC memories. In particular, as an electrochemical cell used for supporting data writing to a memory when an instantaneous blackout occurs and smoothing a circuit voltage, an electric double layer capacitor whose resistance is reduced by winding or stacking is known. ing. A laminate type has been conventionally used as a package for these electrochemical cells. On the other hand, as shown in Patent Document 1, an electrochemical cell using a ceramic package has been proposed in order to have a better sealing property, improve long-term reliability, and respond to reflow soldering.

JP, 2013-30750, A

By the way, in the electrochemical cell using the ceramic package of Patent Document 1, in order to achieve low resistance and high capacity, an electrode sheet in which a current collector such as aluminum is coated with an active material such as activated carbon is wound with a separator. An element (cell) is created by spinning, stacking, or the like.
Here, as the characteristics of the electrochemical cell, various capacities and resistances may be required depending on the specifications of the mounted equipment. In the case of a large package size using an aluminum laminated cell or the like, it is possible to cope with the change in capacitance by changing the area of the same type of electrode sheet having the same activated carbon layer thickness.

However, when cells are housed in a small package such as a ceramic package, the amount of the electrode sheet that can fit in the package is limited, and thus it is difficult to change the capacitance by changing the area of the electrode sheet. On the other hand, by using an electrode sheet in which the thickness of activated carbon is variously changed, it is possible to realize a capacity that meets the requirements of a device equipped with an electrochemical cell. However, in the case where an electrode sheet having various characteristics is manufactured each time, there is a problem in that the cost is not suitable.

Therefore, in view of the above problems, it is an object of the present invention to efficiently provide an electrochemical cell having characteristics according to specifications such as capacitance and resistance required by a mounted device.

(Claim 1)
In the invention according to claim 1, the base container 2, the insulator (separator 6a) , the one electrode sheet 60, the insulator, and the other electrode sheet 60 are stacked in this order , and in the base container 2. a cell 6 is housed, said a cell read 8 extending respectively from two opposite sides of each electrode sheet 60 consists of the base container 2 of a valve metal formed on the bottom surface, at least a pair of the electrode sheet 60 The pad film 5 to which one of the cell leads 8 is connected, the intra-base wiring (via wiring 3) connected to the pad film 5 and formed on the bottom surface of the base container 2, and the upper surface of the base container 2 An electrochemical cell 1 having at least a bonded seal ring 9 and a lid 10 bonded to the upper surface of the seal ring 9 and closing the upper surface of the seal ring 9 , wherein the cell 6 is each The other electrode sheets 60 are folded inward so that the cell leads 8 facing each other for each electrode sheet 60 overlap with each other, the insulator covers the outside, and the other electrode sheets 60 overlap with each other. It is characterized in that a plurality of the cells 6 selected from the cells 6 having a plurality of kinds of thicknesses with different set folding numbers are stacked and housed in the base container 2.

In the present invention, the pad film 5 is for fixing the cell lead 8 and also protects the in-base wiring (via wiring 3) from being exposed to the base bottom surface 2c.
According to the present invention, a plurality of cells 6 are combined according to the inner size of the base container 2 to efficiently provide an electrochemical cell having characteristics according to specifications such as capacity and resistance required by the mounted device. be able to.
In particular, it is possible to provide electrochemical cells having different capacities by preparing in advance a plurality of types of cells 6 having different numbers of folding times of the electrode sheet 60 and changing the combination of the plurality of cells 6.

(Claim 2)
The invention according to claim 2 is a cell in which the base container 2, the one electrode sheet 60, the insulator (separator 6a), and the other electrode sheet 60 are stacked in this order and housed in the base container 2. 6, a cell lead 8 extending from two opposite sides of each electrode sheet 60, and a valve metal formed on the bottom surface of the base container 2, and the cell lead of at least one of the pair of electrode sheets 60. Pad film 5 to which 8 is connected, in-base wiring (via wiring 3) connected to the pad film 5 and formed on the bottom surface of the base container 2, and a seal joined to the upper surface of the base container 2. An electrochemical cell 1 having at least a ring 9 and a lid 10 joined to the upper surface of the seal ring 9 and closing the upper surface of the seal ring 9, wherein the cell 6 includes each electrode sheet 60. The other electrode sheet 60 is folded inward so that the cell leads 8 facing each other overlap each other, the one electrode sheet 60 covers the outside, and the other electrode sheet 60 overlaps. The plurality of cells 6 selected from the cells 6 having a plurality of different thicknesses, which are different in the number of foldings, are stacked and stored in the base container 2 in a state of being covered with the insulator. Characterize.
As in the present invention, even if the electrode sheet 60 is exposed on the surface that comes into contact with another cell 6, if the polarities are the same, a short circuit does not occur even if they are brought into direct contact and combined. Therefore, according to the present invention, in addition to the effects of the present invention, since the insulator (separator 6a) does not exist between the cells 6 to be combined, the size of the unit 6u including a combination of a plurality of cells 6 can be reduced. can do.
(Claim 3)
According to a third aspect of the invention, in addition to the features of the invention, the electrode sheet 60, which active material 62 on the metal substrate 61 is fixed, the layer formed by the front Kikatsu material 62 A plurality of types of the cells 6 including the cells 6 having different thicknesses are stacked .

The present invention adjusts the capacity of the cell 6 by changing the thickness of the layer formed by the active material 62 in the cell 6 formed by the electrode sheet 60 in which the active material 62 is fixed to the metallic base material 61. To do.
According to the present invention, in addition to the effects of the above-described invention, a plurality of types of cells 6 having different thicknesses of layers formed by the active material 62 are prepared in advance, and the combination of the plurality of cells 6 is changed, whereby Different electrochemical cells can be provided.

According to the present invention, it is possible to efficiently provide an electrochemical cell having characteristics according to specifications such as capacity and resistance required by a mounted device.

It is a perspective view of the electrochemical cell of 1st Embodiment. It is a front sectional view (AA sectional view of FIG. 1) of the electrochemical cell of 1st Embodiment. It is a side surface sectional view (BB sectional drawing of FIG. 1) of the electrochemical cell of 1st Embodiment. It is the (A) top view and the (B) bottom view of the base container of a 1st embodiment. It is a figure explaining the process of folding the electrode sheet and separator of 1st Embodiment. It is a side sectional view of a unit of a 1st embodiment. It is an expanded sectional view of the unit of 1st Embodiment (enlarged sectional view of each layer of FIG. 6). It is a figure explaining the welding of the cell lead and pad film of the electrochemical cell of 1st Embodiment. It is a figure which shows the manufacturing flow of the electrochemical cell of 1st Embodiment. It is a side sectional view of a unit of the modification 1. It is an expanded sectional view of the unit of the modification 1 (enlarged sectional view of each layer of FIG. 10). It is a side sectional view of the unit of the modification 2. It is a figure explaining the process of folding the electrode sheet and the separator of the modification 2. It is a side surface sectional view (CC sectional view of FIG. 13) of the cell which comprises the unit of the modification 2. FIG. It is a figure explaining the process of folding the electrode sheet and the separator of the modification 3. It is a side surface sectional view (DD sectional drawing of FIG. 15) of the cell which comprises the unit of the modification 3. FIG. It is a figure explaining the process of folding the electrode sheet and the separator of the modification 4. FIG. 18 is a side sectional view (a sectional view taken along line EE in FIG. 17) of a cell that constitutes a unit of Modification 4; FIG. 3 is a side sectional view of a conventional wound cell. FIG. 3 is a side sectional view of a conventional laminated cell. FIG. 2 is a plan view of a base container and a stack type cell in a conventional electrochemical cell. FIG. 7 is a side sectional view of a conventional winding type cell in which a cell lead is extended from the center of the cell. It is a figure which compares the structure of the electrode sheet and cell lead in 1st Embodiment and a prior art. It is a side sectional view of an electrochemical cell of a 2nd embodiment. It is a perspective view of a base container of an electrochemical cell of a 3rd embodiment. It is sectional drawing of the electrochemical cell of 3rd Embodiment. It is sectional drawing of the electrochemical cell of 4th Embodiment.

Hereinafter, each embodiment will be described with reference to the drawings. The direction of the electrochemical cell 1 is based on the case where the long side is viewed from the front. Further, the directions of the electrode sheet 60 and the separator 6a before folding are also based on the case where the long side is viewed from the front. That is, the front side of the long side is “front”, the back side is “rear”, the left side of the short side is “left”, and the right side is “right”.

(First embodiment)
The electrochemical cell 1 of the present embodiment will be described with reference to the drawings. The electrochemical cell 1 of the present embodiment is mainly used by being mounted on a substrate inside a personal computer or a small portable device.

(Electrochemical cell 1)
FIG. 1 is a perspective view of an electrochemical cell 1 of this embodiment. Although shown as an example of a rectangular parallelepiped shape, it may be a track shape or a cylindrical shape. The electrochemical cell 1 according to the present embodiment includes a base container 2 that functions as a container for accommodating the cell 6 that is the power generating element, and a lid 10 that functions as a sealing plate for hermetically closing the opening thereof as exterior parts. I have it. The outer container of the electrochemical cell 1 of the present embodiment is composed of this base container 2 and a lid 10 that seals the opening of the base container 2. The electrochemical cell 1 of the present embodiment has a size of 10 mm in length×8 mm in width×1.3 mm in height.
Here, in the present embodiment, a plurality of types of cells 6 having different thicknesses of the active material 62 layer are prepared in advance, and the plurality of cells 6 can be combined according to the capacity required by the mounted device. Then, in the present embodiment, the unit 6u is formed by stacking cells 6 of the same type or different types in an upper and lower two stages, and the unit 6u is housed in the base container 2, whereby the electrochemical cell 1 is formed. Manufactured.

2 is a front sectional view of the electrochemical cell 1 of the present embodiment (a view showing a cross section taken along the line AA in FIG. 1), and FIG. 3 is a side sectional view of the electrochemical cell 1 of the present embodiment (B of FIG. 1). It is a figure showing the -B cross section). As shown in FIG. 2 and FIG. 3, a unit 6u formed by stacking two cells 6 is housed in a concave base container 2 and further filled with an electrolyte 7. It is hermetically sealed by a lid 10 pressed against a seal ring 9 provided as above. On the base bottom surface 2c of the concave base container 2, a pair of pad metal films 5 as current collector metal films are arranged side by side. A plurality of via wirings 3 are formed from the bottom surface 2c of the pad film 5 to the bottom surface 2d of the base (see FIG. 4A). The via wiring 3 electrically connects the pad film 5 and the connection terminal 4 formed on the lower surface 2d of the base.

As shown in FIG. 5(A), each cell 6 constituting the unit 6u is formed by inserting a pair of electrode sheets 60, which are current collectors of the positive electrode 6b and the negative electrode 6c, and inserting the insulating separator 6a. It is the generated power element.
In the electrode sheets 60 of the positive electrode 6b and the negative electrode 6c, a part of the electrode sheet 60 is extended outward (sideward) on two opposing sides (short side). In the present embodiment, this extended portion becomes the cell lead 8 that connects the electrode sheet 60 as the current collector and the pad film 5. Further, the electrode sheet 60 and the separator 6a are folded so that the cell leads 8 are overlapped for each electrode (see FIGS. 5B and 5C). Then, the folded cells 6 are stacked so that the exposed surfaces of the separator 6a are in contact with each other to form a unit 6u (see FIG. 6A). Further, the cell leads 8 of the two cells 6 forming the unit 6u are fixed to the pair of pad films 5 by welding. The positive electrode 6b and the negative electrode 6c of the cell 6 are electrically connected to the mounting pattern of the substrate to be mounted by the connection terminal 4.

(Base container 2)
As shown in FIGS. 2 and 3, the base container 2 is a container made of box-shaped ceramics having an open top, and has a rectangular base bottom portion 2a and a rectangular frame shape that is erected on the outer edge of the base bottom portion 2a. It has a base wall portion 2b. The size of the base container 2 of the present embodiment is 10 mm in length×8 mm in width×1.3 mm in height. The size of the base container 2 may be about 5 to 20 mm on each side, and the height may be about 1 to 3 mm. 4A and 4B are views showing the base bottom surface 2c and the base bottom surface 2d of the base container 2, respectively. A pair of pad films 5 made of a conductive material are arranged on the bottom surface 2c of the base shown in FIG. Four via wirings 3 indicated by broken lines are provided on the lower surface of the pad film 5 and are vertically connected to the connection terminals 4 (also indicated by broken lines) arranged on the lower surface 2d of the base.

Examples of the material for the base container 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, but are not limited thereto. Absent. Soda lime glass and heat resistant glass can also be used. Since a long glass can be used as a material, a large number of glass can be set for one glass in the case of a small package, and cost reduction of members related to the base container 2 can be expected.

In the base container 2 of the present embodiment, after the ceramic green sheet corresponding to the base bottom portion 2a punched in a rectangular shape is bonded to the ceramic green sheet corresponding to the base wall portion 2b punched in a rectangular frame shape, It is formed by firing. The through holes can be formed by making holes in the ceramic green sheet corresponding to the base bottom portion 2a in advance by punching.

(Via wiring 3)
The via wiring 3 is a wiring formed from the base bottom surface 2c of the base container 2 to the base lower surface 2d. The via wiring 3 is formed by first forming a through hole in the base bottom portion 2a for penetrating the base bottom surface 2c and the base lower surface 2d to be connected substantially vertically, and filling the through hole with a tungsten paste. It Further, the via wiring 3 fills the airtightness of the through hole.

As the paste used for the via wiring 3, a paste in which carbon and a resin are mixed, a paste in which tungsten, molybdenum, nickel, gold, or a composite material of these materials and a resin are mixed can be used.
The paste filled in the through holes becomes the via wiring 3 by firing together with the ceramic green sheet that becomes the base container 2.

As described above, when the base container 2 is formed of a glass material such as soda lime glass or heat-resistant glass, the means for forming recesses or through holes in these glasses is a chemical etching method, sandblasting, or the like. The recess and the through hole can be formed at the same time by a physical method or by using a mold in a high temperature atmosphere. Then, after forming an aluminum film on the inner surface of the through hole, the through hole is filled with a glass paste having a matched coefficient of thermal expansion, and binder removal and firing are performed to form an airtight and conductive via wiring 3. Can be formed. In such a case, there is no concern that the via wiring 3 will be dissolved by the electrolyte 7. Further, the film forming the inner surface of the via wiring 3 is not limited to aluminum and may be a film containing other valve metal such as titanium.

(Connection terminal 4)
A pair of connection terminals 4 are provided on the lower surface 2d of the base shown in FIG. 4B so as to face the pad film 5. The connection terminal 4 is fixed to the board by cream solder or the like provided on the pattern of the mounting board by a reflow process or the like.
In the present embodiment, the connection terminal 4 can be formed by printing an electrode pattern made of tungsten in advance on the ceramic green sheet that will be the base container 2 and firing the ceramic green sheet. The connection terminal 4 has a pattern of tungsten formed by a printing method and a plating film made of nickel and gold. Further, tungsten and these plating materials are patterned in the recesses on the side surface 2e of the base to function as part of the connection terminals.

(Pad film 5)
The pad film 5 is a substantially rectangular film made of a conductive material and arranged at two positions on the bottom surface 2c of the base. The pad film 5 has a welded portion 5a for preventing direct contact between the upper end of the via wiring 3 and the electrolyte 7 and for connecting the cell lead 8 by welding (see FIG. 4A). .. Although the pad films 5 of the present embodiment are juxtaposed in the longitudinal direction of the base container 2, they can be juxtaposed in the short side direction or in the diagonal direction of the longitudinal direction.

The pad film 5 is a film made of a chemically stable valve metal such as aluminum or titanium and is made of a material that is difficult to dissolve in the electrolyte 7. These films can be provided by a known film forming method such as vapor deposition, ion plating or sputtering. In the case of these methods, first, a metal such as tungsten is filled in the through holes by a printing method or the like and baked to finish the airtight via wiring 3, and then the via wiring 3 is formed. When the film is formed in a vacuum, for example, a mask made of metal or the like that is patterned to have two openings spatially separated from each other so as to form the positive and negative pad films 5 is prepared, and the film is formed. It is housed in the chamber of the, and after it is evacuated to a predetermined degree of vacuum by the vacuum exhaust system, it is evaporated with the valve metal material, or the target made of the valve metal material is physically hit with ions to fly the material, A film is formed on 2c. In these film forming methods, since the film forming conditions are easily controlled, it is possible to form a high density film in which the formed film has a low resistivity and a liquid hardly penetrates.

The aluminum film can also be formed by a screen printing method. A technique has been developed that can form a wiring pattern at a temperature of 150° C. or lower even for aluminum that is easily oxidized at high temperatures. Since it is a printing method, it is thicker than a thin film forming technique such as a vapor deposition method, and a thick film of several tens of microns is easy.
Further, the aluminum film can be produced by an electroplating method. It is known that a film formed with a plating solution of dimethyl sulfone and aluminum chloride to a film thickness of about 40 μm has a smooth surface and a uniform film inside.

Next, the thickness of the pad film 5 will be described. The film thickness is preferably 5 μm or more and 100 μm or less. The range of 10 μm or more and 30 μm is preferable. If the film thickness is thin, the fine pores existing inside the film are connected and the electrolyte 7 easily penetrates into the tungsten under the pad film to cause electrolytic corrosion of the tungsten. As will be described later, the cell lead 8 is welded. This is because the welding conditions are extremely limited and it is difficult to realize a reliable joint when connected with the.

Here, an aluminum film having a thickness of 5 μm of the pad film 5 is formed on a soda lime glass plate having a thickness of about 1.3 mm by the ion plating method, and then a thin plate of aluminum having a thickness of 80 μm is welded by ultrasonic welding. Experiments were conducted. Generation of minute cracks was observed on the glass plate in one of the five cell leads. Therefore, 5 μm is a practical lower limit value for the film thickness. Practically, it is desirable that the film thickness is 10 μm or more.

On the other hand, the deposition rate of aluminum by the vapor deposition method or the ion plating method is 3 μm to 10 μm per hour. Considering the vapor deposition time, a thickness of 30 μm or less is preferable, and the film formation time in this case is about 4 to 5 hours at the longest. When the film is formed to a thickness of about 100 μm, the film forming time is long, but the welding conditions when connecting to the cell lead 8 by welding can be widened, and cracks may be induced in the underlying ceramics. It can be extremely low.

(Cell 6)
Next, the cell 6 housed in the base container 2 will be described. As described above, in the present embodiment, a plurality of types of cells 6 having different active material 62 layer thicknesses are prepared in advance, and the plurality of cells 6 can be combined according to the capacity required by the mounted device. .. Then, in the present embodiment, the unit 6u is formed by stacking cells 6 of the same type or different types in an upper and lower two stages, and the unit 6u is housed in the base container 2, whereby the electrochemical cell 1 is formed. Manufactured.
As described above, these cells 6 are configured by folding a pair of electrode sheets 60, which are collectors of the positive electrode 6b and the negative electrode 6c, with the insulating separator 6a inserted (see FIG. 5). ). The electrode sheet 60 of the present embodiment is formed of a base material 61 which is a strip-shaped foil material made of aluminum and an active material 62 which is a carbon material such as activated carbon fixed to the base material 61 via aluminum carbide. There is.

Specifically, the cell 6 of this embodiment is formed as follows. First, the aluminum foil having a thickness of 5 μm to 50 μm is cut to form the base material 61. Specifically, the cut base material 61 has a strip-shaped portion to which the active material 62 is fixed, and a portion that becomes the cell lead 8 extending from each of two short sides of the strip portion. Next, the active material 62 is fixed to the surface of the strip-shaped portion of the base material 61 by coating or an adhesive method. More specifically, the active material 62 is fixed to the opposing surface of the base material 61 on the electrode side. That is, in FIG. 5A, the active material 62 is formed on the upper surface side of the base material 61 on the positive electrode 6b side and on the lower surface side of the base material 61 on the negative electrode 6c side.
Then, in the present embodiment, a plurality of types of cells 6 having different thicknesses of the active material 62 layer are prepared, and these cells 6 can be combined according to the target capacity.

As shown in FIG. 5(A), the positive electrode cell leads 8b of the positive electrode 6b are formed at the left and right ends of the rear end of the electrode sheet 60, and the negative electrode cell leads 8c of the negative electrode 6c are left and right ends of the front end of the electrode sheet 60. Is formed in the part. That is, the positive electrode cell lead 8b and the negative electrode cell lead 8c are formed at positions where they do not overlap each other when viewed from above.

Next, a process of folding the cell 6 will be described. First, as shown in FIG. 5(A), the respective elements of the cell 6 are stacked in this order from the electrode sheet 60, the separator 6a, the electrode sheet 60, and the separator 6a. Then, as shown in FIG. 5B, the cell 6 is folded such that the negative electrode 6c is on the inner side, and the positive electrode cell leads 8b facing each other and the negative electrode cell leads 8c facing each other overlap each other. At this time, a bent portion 65 that is a fold is formed in the cell 6 on the side facing each cell lead 8. In addition, in the cell 6 of the present embodiment, since the cell leads 8 extending two by two in each electrode sheet 60 are formed at the positions facing each other, the alignment when folding is facilitated.

As described above, in the present embodiment, the cell 6 shown in FIG. 5C is completed by folding the electrode sheet 60 and the separator 6a in the direction in which the cell leads 8 extend (left and right in the drawing) in a state where they are stacked. To do. In the present embodiment, the unit 6u is formed by stacking and combining the cells 6 in upper and lower two stages. A cross section of this unit 6u is shown in FIG. Each cell 6 has a bent portion 65, and the electrode sheet 60 on the side of the positive electrode 6b and the electrode sheet 60 on the side of the negative electrode 6c form a plurality of layers in the vertical direction with the separator 6a interposed therebetween.

Here, in the case of the electric double layer capacitor, a typical material of the active material 62 is activated carbon or carbon. 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 (LiFePO ₄ ). As the negative electrode active material, for example, graphite, coke, silicon oxide, or the like is used. The active material paste, the above active material, a conductive auxiliary agent, a binder, a dispersant and the like is adjusted to a suitable viscosity, by roller coating, screen coating, a method such as a doctor blade method, The base material 61 as a current collector is coated on both sides or one side. After coating, a drying and pressing process is performed to form an electrode sheet.

The electrodes may be formed as follows. That is, a carbon material (activated carbon or the like) or a material such as oxide particles of a valve metal such as titanium or the like may be adhered and formed on a base material 61 made of an aluminum foil as a current collector through aluminum carbide. .. Since such an electrode material has high adhesion to aluminum, the resistance at the interface can be reduced. Further, since the adhesiveness can be maintained even by the heat of the reflow soldering, the electrical characteristics can be maintained even after the reflow soldering. The capacity can be increased by applying the above-mentioned activated carbon or the like to the electrode thus formed.

The separator 6a regulates direct contact between the positive electrode 6b and the negative electrode 6c, and an insulating film having a large ion permeability and a predetermined mechanical strength is used. For example, in an environment where heat resistance is required, in addition to glass fiber, resins such as polytetrafluoroethylene (PTFE), polyphthalamide, polyether ether ketone, polybutylene terephthalate, polyphenylene sulfide, polyethylene terephthalate, polyamide and polyimide are used. Can be used. The pore diameter and thickness of the separator 6a 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 ceramic body as the separator 6a.

(Unit 6u)
6A and 6B are cross-sectional views of a unit 6u including a combination of two cells 6. FIG. 6A is an example in which cells 6 of the type having the same thickness of the active material 62 layer are stacked. FIG. 6B is an example in which cells 6 of different types having different active material 62 layers are stacked. Supplementally, in the unit 6u of FIG. 6B, the active material 62 layer of the upper cell 6 is formed thicker than the active material 62 layer of the lower cell 6, and the cells 6 having different capacities are combined. (See Figure 7).

The cell leads 8 extending from each cell 6 are grouped into cell leads 8 having the same polarity, and are folded back so as to be arranged at the bottom of the cell 6 when the unit 6u is housed in the base container 2. Specifically, a total of four positive electrode cell leads 8b extending from the cells 6 stacked in two stages are present in a state of being stacked on the bottom of the cell 6. Further, at a position apart from the positive electrode cell lead 8b, a total of four negative electrode cell leads 8c extending from the cells 6 stacked in two stages are present in a state of being stacked on the bottom portion of the cell 6.

(Electrolyte 7)
The electrolyte 7 is preferably a liquid or gel electrolyte used in known electric double layer capacitors and non-aqueous electrolyte secondary batteries.
The organic solvent used for the liquid and gel electrolyte 7 includes acetonitrile, diethyl ether, diethyl carbonate, dimethyl carbonate, 1,2-dimethoxyethane, tetrahydrofuran, propylene carbonate (PC), ethylene carbonate (EC), There are γ-butyrolactone (γBL), sulfolane, propionate, chain sulfone and the like, and these can be used alone or in combination.

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

Materials contained in the liquid and gel electrolytes 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 trifluorometasulfonate (LiCF ₃ SO ₃ ), lithium bistrifluoromethylsulfonylimide [LiN (CF ₃ SO ₂ ) ₂ ], thiocyanate, aluminum fluoride, 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 compounds having only an aliphatic chain, alicyclic compounds having an aliphatic chain and an aliphatic ring, and spiro compounds having only an aliphatic ring. In particular, 5-spironiaspiro[4,4]nonanetetrafluoroborate (spiro-(1,1′)-bipyrrolidinium:SBP-BF4), which is a spiro compound, is suitable for use because of its high electrical conductivity. It is not limited.

The gel electrolyte 7 is obtained by impregnating a polymer gel with a liquid electrolyte. Suitable polymer gels include, but are not limited to, polyethylene oxide, polymethylmethacrylate, polyvinylidene fluoride.
Further, room temperature molten salts such as pyridine-based, alicyclic amine-based, aliphatic amine-based, imidazolium-based ionic liquids and amidine-based may be used.

(Cell lead 8)
The cell lead 8 is a terminal for extracting electric power from the cell 6. The cell lead 8 has an extension part in which a base material 61 as a current collector is thinly extended, or another thin and thin plate or a wire-shaped lead is mechanically connected to the base material 61 to form an extension part. is there. The cell lead 8 of the present embodiment is an extended portion obtained by thinly extending the base material 61. Specifically, in the positive electrode 6b and the negative electrode 6c, the two short sides of the strip portion to which the active material 62 of the base material 61 is fixed. The base material 61 is extended. As described above, the positive electrode cell lead 8b and the negative electrode cell lead 8c are formed at positions where they do not overlap each other when viewed from above.

8A and 8B are views for explaining the welding of the cell lead 8 and the pad film 5. As shown in FIGS. 8(A) and 8(B), in the cell 6 constituting the unit 6u, the welding region 8a which is a part of the cell lead 8 is welded to the welding portion 5a of the pad film 5 (see FIG. 4A). It has been fixed by. After the cell lead 8 and the pad film 5 are welded, the cell lead 8 is folded and stored in the base container 2 as shown in FIG.

As shown in FIGS. 8(A) and 8(B), the cell lead 8 has a length such that the cell 6 can be moved to the side of the base container 2, and the ultrasonic wave is used when welding with the pad film 5. It is desirable that the length is such that it does not hinder the movement of the welding tip 20. This is because if it is excessively long, the internal resistance increases.

Further, if the cell lead 8 is long and is largely bent to the side of the unit 6u (cell 6), it may come into contact with the seal ring 9 depending on the position of the cell lead 8 extending from the cell 6. Further, when the brazing material for joining the upper end of the base wall portion 2b and the seal ring 9 protrudes to the base wall portion 2b side, the cell lead 8 may come into contact with the brazing material. An internal short circuit occurs when the cell lead 8 comes into contact with a member connected to the electrode side different from the cell lead 8. Here, as shown in FIGS. 6A and 6B, if the cell lead 8 is connected to the pad film 5 along the side surface of the unit 6u (cell 6), the cell lead 8 is An internal short circuit can be avoided without touching the seal ring 9.

(Welding method for cell lead 8)
Next, a specific welding method of the cell lead 8 and the pad film 5 will be described with reference to FIGS. 8(A) and 8(B). FIG. 8A is a diagram showing a bundle of a pair of cell leads 8 connected to each cell 6 and a pair of pad films 5. As shown in FIG. 8A, the tip ends of the pair of cell leads 8 stacked for each electrode are placed on the surface of the pad film 5 and then welded from the upper surface of the cell lead 8 so that the pad film 5 and the cell lead 8 are separated from each other. To be joined. The pair of cell leads 8 of the positive electrode 6b and the negative electrode 6c may be welded to the pad film 5 after being previously welded and integrated.

By using welding, atomic diffusion of the materials forming the respective members occurs at the bonding interface between the cell lead 8 and the pad film 5, and strong bonding becomes possible. The welded area 8a in FIG. 8A schematically shows the welded portion. Since welding is used, even if contamination such as a natural oxide film is present at the bonding interface, it is possible to achieve bonding with a connection resistance in the order of mΩ or sufficiently low, which is mΩ or less. As a result, the connection resistance can be reduced to 1/10 to 1/100 of that of the joining method using a conductive adhesive or the like. In addition, it is possible to suppress the variation in the connection resistance value and to perform the bonding with less change over time.

Further, by increasing the areas of the welded portion 5a and the welded region 8a, the connection resistance value can be further reduced and the tensile strength between the cell lead 8 and the pad film 5 can be improved. Therefore, in the manufacturing process in which the cell lead 8 is deformed to store the cell 6 inside the container, it is possible to suppress the occurrence of defects such as peeling of welding, and to improve the vibration resistance characteristic and the drop impact characteristic of the completed electrochemical cell 1. The mechanical reliability can be improved.

Examples of the welding of the cell lead 8 and the pad film 5 include local welding methods such as ultrasonic welding, beam welding, and resistance welding. That is, in these welding means, since the portion to be welded is local, the thermal influence is limited to the vicinity of the welded portion 5a, and the influence on the cell 6 itself can be avoided. Further, by changing the material and thickness of the cell lead 8, the material of the pad film 5 and the arrangement of the through holes, it is possible to reduce the influence of mechanical or thermal shock of welding on the constituent members. With the above configuration, it is possible to avoid damage to the members due to the generation of cracks even in the base container 2 made of a material such as ceramics.

In the present embodiment, of the above welding methods, ultrasonic welding is adopted. FIG. 8B is a diagram for explaining a specific method of ultrasonic welding. In ultrasonic welding, first, the cell leads 8 are positioned and brought into close contact with each other on the pad film 5, but at this time, the unit 6u does not interfere with the movement of the ultrasonic welding tip 20. It is placed upright. Next, the ultrasonic welding tip 20 is brought into contact with the upper surface of the cell lead 8 with an appropriate pressing force by the moving mechanism. The ultrasonic welding tip 20 is integrally formed at the tip of the horn, or is separately attached to the tip of the horn. The tip end 20a of the ultrasonic welding tip 20 is a portion that comes into contact with the cell lead 8, and the surface of the cell lead 8 is provided with an uneven pattern so as to appropriately bite into the surface (knurling). Is preferred.

After the ultrasonic welding tip 20 is brought into contact with the cell lead 8 with an appropriate pressure, when the ultrasonic mechanism of the ultrasonic welding machine applies an ultrasonic wave of several tens of kHz to the horn, the ultrasonic welding tip 20 has a frequency. Rub the joints with. As a result, the interface between the welded region 8a of the cell lead 8 and the welded portion 5a of the pad film 5 becomes a contact surface between the clean surfaces of the metal material, and is brought into pressure contact in a short time of several tens to several hundreds of milliseconds. be able to. The concavo-convex pattern on the surface of the cell lead 8 shown by the welding region 8a in FIG. 8A above schematically shows that the concavo-convex pattern of the ultrasonic welding tip 20 is transferred by this ultrasonic welding. It is a thing. The region indicated by this concave-convex pattern is the welding region 8a, but when viewed microscopically, the joined portion is only the portion that is recessed by the protrusion processed at the tip of the ultrasonic welding tip 20. In the other regions, a slight gap is maintained between the cell lead and the pad film.

When the ultrasonic welding tip 20 comes into contact with the surface of the cell lead 8, it is preferable to be careful not to give a large impact, and the moving mechanism may be provided with an impact absorbing mechanism such as a damper. Thereby, damage to the base container 2 can be reduced.
In ultrasonic welding, not only vibration but also thermal energy and mechanical pressure contact force can be used together. In addition, in FIG. 8A, a thin plate-shaped example is shown as the cell lead 8, but a wire may be used, and the shape of the ultrasonic welding tip 20 may be appropriately deformed and used.

Further, when pressure, heat, and vibration are applied to the pad film 5 by welding, the adhesion of the pad film 5 to the base bottom surface 2c and the via wiring 3 is deteriorated, and the pad film 5 itself is cracked or broken. In particular, when pressure, heat, and vibration are applied to the pad film 5 near the via wiring 3 and the adhesion is lost, the electrical connection between the pad film 5 and the via wiring 3 is lost, and the upper end surface of the via wiring 3 is Upon contact with the electrolyte 7, the via wiring will be eluted into the electrolyte 7. Therefore, it is desirable to provide the welded portion 5a in a portion that does not overlap the via wiring 3.

(Seal ring 9)
As shown in FIGS. 1 and 2, the seal ring 9 has a rectangular frame-shaped cross section that matches the shape of the upper end surface of the base wall portion 2b of the base container 2, and the upper end surface of the base wall portion 2b is It is joined through a brazing material. For the seal ring 9, a material having a thermal expansion coefficient close to that of ceramics, for example, Kovar which is an iron-cobalt-nickel alloy can be used. The brazing material is made of Ag—Cu alloy, Au—Cu alloy, or the like.

(Lid 10)
As shown in FIGS. 1 and 2, the lid 10 is joined to the upper surface of the seal ring 9 and seals the base container 2. For the lid 10, an alloy such as Kovar or 42 alloy having a coefficient of thermal expansion close to that of ceramics plated with nickel is used. Specifically, a Kovar thin plate having a thickness of about 0.1 mm to 0.2 mm and having a surface plated with electrolytic nickel or electroless nickel with a thickness of about 2 μm to 4 μm is used. The lid 10 using such a material can be welded to the seal ring 9 by, for example, resistance seam welding or laser seam welding, and improves the airtightness of the inside of the base container 2 in the closed state.

In resistance seam welding used as a method of welding the lid 10 and the seal ring 9, after the lid 10 is brought into contact with the seal ring 9, two trapezoidal shapes facing each other are formed at two points on the long side of the lid 10 at substantially the center. The roller electrode is arranged and a low voltage and a large current is passed for a short time to perform temporary welding (spot welding) of the lid 10. In this way, the lid 10 is temporarily fixed and will not be displaced due to vibration during welding or the like.

Then, for example, the base container 2 and the lid 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 container 2 and the lid 10 are rotated 90 degrees, and the short sides are similarly welded. In this way, welding is performed over the entire circumference of the lid 10. In both the temporary fixing and the resistance seam welding described above, diffusion of gold and nickel occurs at the interface between the lid 10 and the seal ring 9, and an airtight and strong diffusion bonding layer is formed. As a result, the lid 10 is hermetically sealed in the base container 2.

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

When the electrolyte 7 is composed of a solvent or supporting salt that is liquid at room temperature and the step of filling the electrolyte 7 before sealing the lid 10 is adopted, the liquid exists at the interface between the lid 10 and the seal ring 9. There can be a place. 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 reason why the airtight welding is possible even if the liquid is present at the interface is that the liquid present at the interface evaporates and scatters because the temperature in the vicinity rapidly rises during welding.

The upper end surface of the base container 2 and the lid 10 may be joined via a brazing material without using the seal ring 9.

(Production method)
Next, the manufacturing method of the present embodiment will be described with reference to the manufacturing flow of the electric double layer capacitor shown in FIG. First, as an outer container, a base container 2 having a concave shape shown in FIGS. 1 to 3 and a lid 10 were prepared. The base container 2 has a long side of 10 mm, a short side of 8 mm, and a height of 1.3 mm, and the base container 2 has a bottom side thickness of 0.38 mm. As a material, a standard material used for manufacturing a package of an electronic component with ceramics was used. This base container 2 has a ceramic green sheet corresponding to the base bottom portion 2a punched in a rectangular shape, and a ceramic green sheet corresponding to the base wall portion 2b punched in a rectangular frame shape. It is formed by firing. The via wiring 3 had an outer diameter of 0.2 mm, and four via wirings were provided on each of the positive electrode side and the negative electrode side so as to directly penetrate the base bottom surface 2c and the base lower surface 2d. The surface of the via wiring 3 was plated with nickel and gold. A pair of connection terminals 4 is arranged on the lower surface 2d of the base and is connected to the via wiring 3. The connection terminal 4 is plated with gold using nickel as a base (S10).

Next, a pair of pad films 5 made of a vapor deposition film of aluminum were formed on the bottom surface 2c of the base. The pad film 5 has a short side of 2.4 mm, a long side of 5 mm, and a thickness of about 15 μm or more (S11).
On the other hand, as the lid 10, a Kovar plate having a long side of 9 mm, a short side of 7 mm, and a thickness of 0.125 mm was prepared, and the surface thereof was subjected to electrolytic nickel plating (S20).

Then, each cell 6 accommodated in the base container 2 is prepared. An electrode sheet 60 was formed by coating a base material 61 made of aluminum having a thickness of 20 μm with an active material 62 made of activated carbon, a conductive auxiliary agent, a binder and a thickening material by a coating method (S30). In addition, in the electrode sheet 60 of the present embodiment, the cell lead 8 is formed as an extension of the base material 61. The pair of positive and negative electrode sheets 60 and the separator 6a made of polytetrafluoroethylene were alternately stacked and then folded (S31).

A plurality of types of cells 6 having different thicknesses of the active material 62 layer are prepared in advance in the cells 6 formed in this way, and the plurality of cells 6 are combined according to the capacity required by the mounted device. be able to. Then, cells 6 of the same type or different types are overlapped in two layers in the upper and lower layers to form a unit 6u having a desired capacity.

Then, ultrasonic welding is performed. The cell lead 8 stacked for each electrode was brought into close contact with the surface of the pad film 5 of the base container 2 prepared previously and positioned. Ultrasonic welding was performed for each cell lead 8 of each electrode (S32). The oscillation frequency of the ultrasonic welding machine was 40 kHz. The welding horn is made of iron, and the ultrasonic welding tip 20 made of the same material is integrally provided at the tip of the horn. On the surface of the ultrasonic welding tip 20, an uneven pattern (narl) of 0.2 mm pitch in a staggered grid pattern was provided in an area of 2.0×1.5 mm. The difference between the height of the mountain and the bottom of the valley is 0.2 mm. The welding mode was a mode in which the energy supplied to the cell lead 8 during welding was controlled, the set value of welding energy was in the range of 0.5 to 100 J, and the welding time was in the range of 50 to 2000 msec. After the ultrasonic welding tip 20 descends to the surface of the cell lead 8 made of aluminum by an air mechanism, it bites into the surface of the cell lead 8 and vibrates between the interface between the cell lead 8 and the pad film 5 to perform welding. ..

After the welding was completed, the cell lead 8 was folded and the unit 6u including the cells 6 in the upper and lower two stages was housed in the base container 2 (S33).

Next, the base container 2 accommodating the cells 6 was immersed in the liquid electrolyte 7 and vacuum degassed for 1 hour. Here, the supporting salt of the electrolyte 7 was spirobipyrrolidinium tetrafluoroborate, and a mixed solution of propylene carbonate and ethylene carbonate was used as the non-aqueous solvent (S34). Then, after returning to atmospheric pressure and taking out the base container 2 accommodating the cells 6 from the electrolyte 7, the lid 10 is brought into contact with the seal ring 9 in a nitrogen atmosphere, and temporary welding of two points on the long side is performed. Then, resistance seam welding was performed continuously in this order on the long side and the short side to hermetically seal (S35). In this way, the electric double layer capacitor of the present embodiment was manufactured. In addition, the electrical characteristic inspection of the finally manufactured electric double layer capacitor is performed (S36). The item is, but not limited to, the measurement of equivalent series resistance and capacitance.

The electrochemical cell 1 of each of Examples 1 to 5 was manufactured using the unit 6u of the present embodiment, and the capacity and internal resistance with respect to the thickness of 62 layers of the active material were measured.

(About cells A to C)
First, three types of cells 6 that are vertically combined in the unit 6u of each example and in which the thickness of the active material 62 layer is different are prepared. Specifically, three types of cells 6 in which the thickness of the active material 62 layer of the positive electrode 6b and the negative electrode 6c is 30 μm, 40 μm, or 50 μm are prepared. Here, the dimensions of each part in each cell 6 are as shown in Table 1.

According to Table 1, the size of the active material 62 layer and the base material 61 of each cell 6 is 10 mm×7 mm, and the size of the separator 6 a is 12 mm which is slightly larger than the active material 62 layer and the base material 61. ×8 mm. The size of the cell lead 8 is 7 mm×3 mm. As described above, the cell lead 8 is formed integrally with the base material 61, and the cell lead 8 extends outward from the short side of the base material 61.

The only difference between the dimensions of the cells 6 is the thickness of the active material 62 layer. Here, according to Table 1, the height of the cell 6 of the cell A is 320 μm, the height of the cell 6 of the cell B is 360 μm, and the height of the cell 6 of the cell C is 400 μm. The active material 62 layers of the cells A to C are provided in a total of four layers by folding the electrode sheets 60 of the positive electrode 6b and the negative electrode 6c in two. Therefore, the difference in height of each cell 6 is the difference in height of the active material 62 layers by 4 layers.

(About each example)
Next, two cells 6 were combined from these cells 6 to form a plurality of units 6u having different volumes of the active material 62. In each embodiment, the shape of the unit 6u housed in the base container 2 is as shown in FIGS. 6(A) and 6(B). Here, the size of the base container 2 accommodating the unit 6u of each example is the same, and the internal dimensions are 8.4 mm in length×6.4 mm in width×0.92 mm in depth. Then, the above-mentioned three types of cells 6 were combined to form five types of units 6u, which were each housed in the base container 2 to manufacture the electrochemical cell 1.
Table 2 shows the combination of the cells 6 constituting the unit 6u of each example, the height of the unit 6u, the volume of the active material 62 layer, the capacity of the cell 6, and the internal resistance.

As shown in Table 2, Example 1 is a combination of two cells A, Example 2 is a combination of cells A and B, and Example 3 is a combination of two cells B. 4 is a combination of cells B and C, and the fifth embodiment is a combination of two cells C.
In each example, since the cells 6 formed by bending the electrode sheet 60 and the separator 6a twice are stacked in two layers, the positive electrode 6b and the negative electrode 6c have a total of eight layers of the electrode sheet 60 and the separator 6a. Is also in a state of being overlaid with eight layers. Further, the cell leads 8 are in a state in which four layers are stacked on each of the positive electrode 6b and the negative electrode 6c. Therefore, the difference in height of the unit 6u is the difference in the thickness of the active material 62 layers by 8 layers.

When the height of the unit 6u was calculated, the depth of the base container 2 was within a range of 0.72 to 0.88 mm, which was within 0.92 mm.
Further, when the volume of the active material 62 layer was calculated based on the surface area and the thickness of the active material 62 layer, it was in the range of 8.4 to 14.0 mm ³ . In each example, as the active material 62 layer becomes thicker, the volume of the active material 62 layer also increases.

Here, as a result of measuring the capacity of the electrochemical cell 1 of each example, it was in the range of 91 to 141 mF. Although there is a proportional relationship between the volume of the active material 62 layer and the capacity, in Table 2, the volume increases as the thickness of the active material 62 layer increases, that is, as the volume of the active material 62 layer increases. , It is recognized that the two have a proportional relationship.
Moreover, the result of measuring the internal resistance of the electrochemical cell 1 of each example was in the range of 359 to 414 mΩ. Here, the internal resistance of the cell 6 is inversely proportional to the area of the portion where the active materials 62 of the positive electrode 6b and the negative electrode 6c face each other, but when the areas of the facing portions are equal, the internal resistance value becomes constant. Then, the average value of the internal resistance of each example was calculated to be 391 mΩ, and the error (%) from the average value was calculated to be in the range of −8 to 6%. Therefore, the value of the internal resistance in each example falls within the range of 10% from the average value, and if this is regarded as an error, it can be said that the internal resistance value is constant even if the combination of the cells 6 is changed.

As described above, as shown in each of the examples, the unit 6u in which two cells 6 having the same or different thicknesses of the active material 62 layers are combined to facilitate the electrochemical cell 1 having different internal capacities but different capacities. Can be manufactured. If the specifications of the plurality of types of cells 6 are known in advance, it is possible to efficiently manufacture the electrochemical cell 1 having the characteristics according to the specifications such as capacity and resistance required by the mounted device.

(Modification 1)
In the first modification of the first embodiment, the unit 6u is manufactured by reducing the number of separators 6a forming the cells 6. Hereinafter, the differences from the first embodiment will be described.

The process of forming the cell 6 of Modification 1 will be described. First, the electrode sheet 60, the separator 6a, and the electrode sheet 60 are overlaid on top of each other in the order of the elements of the cell 6 (the bottom layer separator 6a shown in FIG. 5A is removed). Next, the cell 6 is folded such that the negative electrode 6c is on the inner side, and the positive electrode cell leads 8b facing each other and the negative electrode cell leads 8c facing each other overlap each other. Then, the folded cell 6 is completed. At this time, the electrode sheet 60 of the positive electrode 6b is exposed on the upper and lower surfaces of the cell 6.

In the modified example 1 as well, a plurality of types of cells 6 in which the thickness of the active material 62 layer is different are prepared. Each cell 6 is folded so that the electrode sheet 60 of the positive electrode 6b is exposed on the upper and lower surfaces.

Next, the unit 6u is formed by stacking two cells 6 of the same type or different types.
FIG. 10 shows an example in which cells 6 of different types having different active material 62 layers are stacked. Supplementally, in the unit 6u of FIG. 10, the active material 62 layer of the upper cell 6 is formed thicker than the active material 62 layer of the lower cell 6, and the cells 6 having different capacities are combined (FIG. 11). reference).

As described above, the electrode sheet 60 of the positive electrode 6b is exposed on the upper and lower surfaces of each cell 6. That is, since the cell 6 is folded so that the electrode sheet 60 of the same polarity is exposed on the surface in contact with another cell 6, short-circuit does not occur even if the two cells 6 are directly stacked and combined (see FIG. 11). Then, after stacking the two cells 6, as shown in FIG. 10, the cells are covered with a separator 6a from the upper surface of the upper cell 6 to the lower surface of the lower cell 6 via the bent portion 65 of each cell 6. This completes the unit 6u.

Further, the cell leads 8 extending from each cell 6 are grouped into cell leads 8 of the same polarity as in the first embodiment, and when the unit 6u is housed in the base container 2, the cells 6 It is folded back so as to be placed at the bottom of the (see FIG. 10). The positive electrode 6b is not necessarily provided for the positive cell lead 8b of the upper cell 6 because the upper cell 6 and the lower cell 6 can be brought into conduction with each other. In this case, by joining the two cells 6 with a conductive adhesive, the conduction of the positive electrode 6b becomes reliable.

As described above, in the unit 6u of Modification 1, the separator 6a does not exist between the two stacked cells 6. When compared in detail with the first embodiment, in the case of the unit 6u of the first embodiment, two separators 6a in each cell 6 are folded in two to form four layers, and further, the cell 6 has two layers. Stacked in columns. Therefore, as shown in the cross-sectional view of FIG. 7, the separator 6a has a total of eight layers. On the other hand, in the case of the unit 6u of Modification 1, one separator 6a in each cell 6 is folded in two to form two layers, and further, after the cells 6 are stacked in two stages, one outer surface is formed. It is wrapped with the separator 6a. Therefore, as shown in the cross-sectional view of FIG. 11, the total number of layers of the separator 6a is six.

As described above, in the unit 6u of the first modification, the height of the separator 6a having a thickness of two layers can be suppressed as compared with the unit 6u of the first embodiment. That is, the height of the unit 6u can be suppressed low by reducing the number of the separators 6a forming the cells 6. When the configuration of the unit 6u according to the modified example 1 is applied to the above-described embodiment, the height of each unit 6u can be reduced by 60 μm.

If the height of the unit 6u can be reduced, the height of the base container 2 can be further reduced. Further, when the size of the base container 2 is not changed in Modification 1, the thickness of the active material 62 layer can be increased by the height of the unit 6u being suppressed low. That is, in the modified example 1, since the unit 6u can be manufactured with the minimum number of separators 6a, it is possible to further increase the capacity of the base container 2 having a limited volume. Further, in the electrode on one side, since the cells 6 can directly contact each other to ensure the conduction, it is possible to further reduce the resistance.

(Modification 2)
In the second modification of the first embodiment, the unit 6u is formed by the cells 6 of the electrode sheet 60 and the separator 6a having different folding numbers. Hereinafter, the differences from the first embodiment will be described.
A cross-sectional view of the unit 6u according to the modification 2 is shown in FIG. In the unit 6u of FIG. 12, the upper cell 6 is formed by folding in four, and the lower cell 6 is formed by folding in half.

A process of folding the upper cell 6 will be described.
13A to 13D are diagrams illustrating a folding method of the upper cell 6 of the second modification. In addition, FIG. 14 is a cross-sectional view (a cross-sectional view taken along the line C-C in FIG. 13) of the upper cell 6 of Modification 2. First, as shown in FIG. 13A, the elements of the cell 6 are stacked in this order from the top, ie, the electrode sheet 60, the separator 6a, the electrode sheet 60, and the separator 6a. Then, as shown in FIG. 13B, the cell 6 is folded such that the positive electrode cell leads 8b facing each other and the negative electrode cell leads 8c facing each other overlap each other. At this time, a bent portion 65 that is a fold is formed in the cell 6 on the side facing each cell lead 8. Since the cell leads 8 extending two by two on each electrode sheet 60 are formed at the positions facing each other, the alignment when folding is facilitated.

Further, as shown in FIG. 13(C), by folding the cell 6 once again so that the bent portion 65 formed when the cell 6 is first folded is located near the base of the cell lead 8, Bent portions 65 are further formed on the opposite sides.
As described above, in Modification 2, the electrode sheet 60 and the separator 6a are overlapped with each other and folded twice in the direction in which the cell leads 8 extend (left and right in the drawing), as shown in FIGS. The cell 6 is completed. FIG. 14 is an enlarged cross-sectional view of the completed cell 6. The cell 6 has two bent portions 65, and the electrode sheet 60 on the positive electrode 6b side and the electrode sheet 60 on the negative electrode 6c side form a plurality of layers in the vertical direction with the separator 6a interposed therebetween.

The method of folding the lower cell 6 is as shown in FIG. 5, and the description is omitted.
Further, the cell leads 8 extending from each cell 6 are grouped into cell leads 8 of the same polarity as in the present embodiment, and when the unit 6u is housed in the base container 2, the bottom portion of the cell 6 is It is folded back so as to be arranged in (see FIG. 12).
As described above, in Modification 2, it is possible to change the capacity of the cells 6 forming the unit 6u by expanding the area of the active material 62 (electrode sheet 60) without changing the thickness of the active material 62 layer. The second modification has the same effects as the present embodiment.

(Modification 3)
The modified example 3 of the first embodiment employs a method different from that of the modified example 2 regarding the folding method of the electrode sheet 60 and the separator 6a. Hereinafter, differences from the first embodiment and the second modification will be described.
In the unit 6u of Modification 3, the upper cell 6 is formed by folding in four, and the lower cell 6 is formed by folding in two.

A process of folding the upper cell 6 will be described.
15A to 15D are diagrams illustrating a folding method of the cells 6 in the upper stage of the third modification. In addition, FIG. 16 is a cross-sectional view (cross-sectional view taken along line DD of FIG. 15) of the upper cell 6 of Modification 3. First, as shown in FIG. 15A, the respective elements of the cell 6 are stacked in this order from the top, ie, the electrode sheet 60, the separator 6a, the electrode sheet 60, and the separator 6a. Then, as shown in FIG. 15B, the cell 6 is folded such that the positive electrode cell leads 8b facing each other and the negative electrode cell leads 8c facing each other overlap each other. At this time, a bent portion 65 that is a fold is formed in the cell 6 on the side facing each cell lead 8. Since the cell leads 8 extending two by two on each electrode sheet 60 are formed at the positions facing each other, the alignment when folding is facilitated.

Further, as shown in FIG. 15(C), by further folding so that the two sides adjacent to the bent portion 65 formed when the cell 6 is first folded are aligned, one side adjacent to each cell lead 8 is formed. Further, the bent portion 65 is formed.

As described above, in Modification 3, once the electrode sheet 60 and the separator 6a are overlapped with each other in the direction in which the cell leads 8 extend (the left-right direction in the figure), the direction orthogonal to the direction in which the cell leads 8 extend (the front-rear direction in the figure). ) Once, the cell 6 shown in FIGS. 15D and 16 is completed. FIG. 16 is an enlarged cross-sectional view of the completed cell 6. The cell 6 further has another bent portion 65 in a direction orthogonal to the two bent portions 65, and a plurality of electrode sheets 60 on the side of the positive electrode 6b and electrode sheets 60 on the side of the negative electrode 6c are vertically arranged via the separator 6a. Are in layers.

The method of folding the lower cell 6 is as shown in FIG. 5, and the description is omitted.
Further, the cell leads 8 extending from each cell 6 are grouped into cell leads 8 of the same polarity as in the present embodiment, and when the unit 6u is housed in the base container 2, the bottom portion of the cell 6 is It is folded back so as to be arranged in (see FIG. 12).
As described above, in Modification 3, it is possible to change the capacity of the cells 6 forming the unit 6u by expanding the area of the active material 62 (electrode sheet 60) without changing the thickness of the active material 62 layer. And the modification 3 has the same effect as this embodiment.

(Modification 4)
Modification 4 of the first embodiment adopts a method of folding the electrode sheet 60 and the separator 6a different from those of Modifications 2 and 3. Hereinafter, differences from the first embodiment, modification 2 and modification 3 will be described.
In the unit 6u of Modification 4, the upper cell 6 is formed by bellows folding, and the lower cell 6 is folded by two.

A process of folding the upper cell 6 will be described.
17A to 17D are diagrams illustrating a folding method of the cells 6 in the upper stage of the fourth modification. In addition, FIG. 18 is a cross-sectional view (cross-sectional view taken along the line EE of FIG. 17) of the upper cell 6 of the modified example 4. First, as shown in FIG. 17A, the elements of the cell 6 are stacked in this order from the top, ie, the electrode sheet 60, the separator 6a, the electrode sheet 60, and the separator 6a. Then, as shown in FIG. 17B, three folded portions 65 are formed by alternately folding left and right so that the length of the electrode sheet 60 in the cell lead 8 direction (horizontal direction) becomes ¼. It

As described above, in Modification 4, as shown in FIGS. 14C and 18, the electrode sheet 60 and the separator 6a are alternately folded in the direction in which the cell leads 8 extend (the left-right direction in the drawing) with the electrode sheet 60 and the separator 6a overlapped with each other. The cell 6 is completed. FIG. 18 is an enlarged sectional view of the completed cell 6. The cell 6 has one bent portion 65 on the left side having the cell lead 8 and two bent portions 65 on the right side facing the cell lead 8, and the electrode sheet 60 on the positive electrode 6b side and the electrode sheet 60 on the negative electrode 6c side are separated by the separator. A plurality of layers are formed in the vertical direction via 6a.

The method of folding the lower cell 6 is as shown in FIG. 5, and the description is omitted.
Further, the cell leads 8 extending from each cell 6 are grouped into cell leads 8 of the same polarity as in the present embodiment, and when the unit 6u is housed in the base container 2, the bottom portion of the cell 6 is It is folded back so as to be arranged in (see FIG. 12).
As described above, in Modification 4, it is possible to change the capacity of the cells 6 constituting the unit 6u by expanding the area of the active material 62 (electrode sheet 60) without changing the thickness of the active material 62 layer. And the modification 4 has the same effect as this embodiment.

(Summary)
The features and effects of the electrochemical cell 1 of the first embodiment are summarized as follows.

(1) Feature point 1
The electrochemical cell 1 of the present embodiment is manufactured by a unit 6u in which a plurality of types of cells 6 having active material 62 layers having different thicknesses are prepared in advance and cells 6 of the same type or different types are combined.

Conventionally, when manufacturing the electrochemical cell 1 according to the specifications such as capacity and resistance required by the mounted equipment, it is not limited to the case where the electrode sheet 60 is of the winding type or the lamination type, and various types of characteristics are used. It was necessary to design the electrode sheet from scratch. On the other hand, if a plurality of types of cells 6 prepared in advance have known capacities, internal resistance values, etc., these cells 6 are combined to meet the specifications such as capacity and resistance required by the mounted device. The electrochemical cell 1 can be manufactured easily and efficiently.

In the present embodiment, the unit 6u is formed by stacking cells 6 of the same type or different types in two stages, but the present invention is not limited to this. That is, the unit 6u may be formed by stacking cells 6 in three or more stages.
Further, when the cells 6 are combined to form the unit 6u, in the present embodiment, the cells 6 are vertically stacked, but the present invention is not limited to this. For example, the cells 6 may be laterally arranged inside the base container 2 to form the unit 6u.
Furthermore, you may form the unit 6u combining each modification mentioned above.

When the capacity of the cell 6 is adjusted by the number of times the electrode sheet 60 and the separator 6a are folded, the folding method is not limited to the methods described in Modifications 2 to 4. If the cell leads 8 facing each other for each electrode sheet 60 are folded so as to overlap each other, the folding method is free.
For example, the cell 6 in which the electrode sheet 60 and the separator 6a are stacked may be folded three or more times in the direction (left-right direction) in which the cell leads 8 extend. Alternatively, for example, the cell leads 8 may be alternately folded in the extending direction (left-right direction) and the direction orthogonal to the extending direction of the cell leads 8 (front-back direction).

(2) Feature point 2
The electrochemical cell 1 of the present embodiment is characterized in that two electrode sheets 60 are stacked and folded with a separator 6a in between to form the cell 6. Here, the conventional method for forming the cell 6 has the following problems.

When the cell 6 is formed by winding the electrode sheet 60 and the separator 6a according to the related art (see FIG. 19), the winding core 68 is applied to the stacked electrode sheet 60 and the separator 6a, and then the winding is performed. The core 68 is pulled out to form the cell 6. Therefore, a space is created in the central portion of the cell 6. It is possible to reduce the volume of the space by reducing the thickness of the winding core 68, but if the thickness is thin enough to deform the winding core 68, the winding operation will be hindered. Therefore, there is a limit in reducing the space by the winding core 68. In addition, after the coil 6 is wound, pressure may be applied to the cell 6 from above to collapse the space inside the cell 6 and then store the cell 6 in the base container, but the height when the cell 6 is collapsed varies widely. Further, even if pressure is applied to the cells 6 from above, only the central portion of the cells 6 is crushed and the height of the periphery is hardly changed, and the height of the cells 6 housed in the base container 2 is hardly reduced. As described above, as a result of having the space inside, the amount of the electrode sheet 60 (active material 62) accommodated in the base container 2 is reduced.

Further, when the cell 6 is formed by stacking the electrode sheet 60 and the separator 6a, which are conventional techniques (see FIG. 20), the electrode sheet 60 should be prevented from coming into contact with the base wall portion 2b of the base container 2 and the seal ring 9. , Its area must be smaller than that of the separator 6a. Therefore, the electrode sheet 60 needs a space around the inside of the base container 2. When the electrode sheets 60 are laminated, the cell leads 8 extending from each electrode sheet 60 are also laminated. Therefore, when the cells 6 are housed in the base container 2, the cell leads 8 of a plurality of layers are present on the lower surface of the cells 6. Become. Therefore, as the number of stacked electrode sheets 60 increases, the height of the storable cell 6 decreases. As described above, the more electrode sheets 60 are stacked, the smaller the amount of the electrode sheets 60 (active material 62) accommodated in the base container 2 is.

On the other hand, in the case of stacking, the cell leads 8 may not be bent and housed in the base container 2, but the cell leads 8 may be welded to the pad film 5 while extending laterally from the cells 6 as shown in FIG. it can. In this case, the height of the cell 6 can be increased because the cell lead 8 is not provided on the lower surface of the cell 6, but the width of the cell 6 in the side portion where the cell lead 8 extends needs to be narrowed. That is, it is necessary to reduce the volume of the cell 6 by the amount that the cell lead 8 is stored laterally. Therefore, when the cell 6 is housed in the base container 2 with the cell lead 8 folded, the electrode housed in the base container 2 is more than in the case where the cell lead 8 is housed in the base container 2 in the extended state. The amount of the sheet 60 (active material 62) is reduced.

As described above, the structure of the conventional technique is limited in the amount of the electrode sheet 60 accommodated in the base container 2. On the other hand, in the present embodiment, as shown in FIGS. 6A and 6B, there is no space in the central portion of each cell 6 that constitutes the unit 6u. In the intermediate layer of the folded and stacked electrode sheet 60, the electrode sheet 60 is continuously present at the bent portion 65 which is the side end portion of the cell 6, and the separator 6a is provided on the base wall portion 2b side. Exists. Therefore, in the present embodiment, it is not necessary to provide a space for preventing the electrode sheet 60 from coming into contact with the base wall portion 2b due to the bent portion 65. Furthermore, since the cell lead 8 of each electrode may be two layers and the unit 6u as a whole may be four layers, it is not necessary to reduce the size of the cell 6 to accommodate the cell leads 8 stacked in a plurality of layers as in the case of stacking.

As described above, according to the present embodiment, in the small electrochemical cell 1 mounted on the electronic substrate, the inside of the base container 2 is used as effectively as possible. An element (active material 62) can be stored. By accommodating more power generation elements (active materials 62), it is possible to manufacture the electrochemical cell 1 having a small cell size, a large cell capacity, and a low internal resistance.

(3) Feature point 3
The electrochemical cell 1 of the present embodiment is characterized in that the cell leads 8 extend from two opposite sides in each of the electrode sheets 60 of the positive electrode 6b and the negative electrode 6c. That is, since the cell leads 8 extending two by two on each electrode sheet 60 are formed at the positions facing each other, the alignment when folding is facilitated.

Further, the cell lead 8 functions as a wiring that electrically connects the cell 6 and the pad film 5, but the smaller the cross-sectional area, the larger the electrical resistance. Here, as shown in FIG. 22, in the cell 6 formed by the conventional winding method, when the cell lead 8 is extended from the center of the cell 6, one cell lead 8 is provided for each electrode sheet 60. is there. On the other hand, in the cell 6 of the present embodiment, since two electrode leads 8 are provided for each electrode sheet 60, the electrical resistance can be reduced by the amount of two cell leads 8 for each cell 6. it can.

(4) Feature point 4
The present embodiment is characterized in that the cell lead 8 is an extended portion of the electrode sheet 60. Specifically, the extended portion of the base material 61 of the electrode sheet 60 is formed as the cell lead 8. Here, when fixing the separate cell lead 8 to the electrode sheet 60, there are the following problems.

FIG. 23A shows the structure of the electrode sheet 60 (on the side of the positive electrode 6b) and the cell lead 8 of this embodiment. On the other hand, in FIGS. 23B and 23C, the cell leads 8 are fixed to the left and right ends of the base material 61 of the electrode sheet 60 by welding. Here, in both cases of FIGS. 23B and 23C, the active material 62 cannot be fixed to the portion of the base material 61 where the cell lead 8 is fixed. Therefore, when the separate cell lead 8 is fixed to the base material 61, there is a problem that the amount of the active material 62 is reduced because the cell lead 8 is fixed.

When fixing the cell lead 8 as a separate body to the base material 61, if the thickness of the cell lead 8 is equal to or more than the thickness of the active material 62, when the electrode sheet 60 and the separator 6a are folded, The area around the fixed part is higher than the surrounding area. That is, since the cell 6 has a shape in which the vicinity of the fixed portion of the cell lead 8 rises, there is a problem that the cell 6 cannot be housed inside the base container 2 without a gap.

On the other hand, according to the present embodiment, since the cell lead 8 and the base material 61 are integrally formed, it is not necessary to reduce the fixed amount of the active material 62 for fixing the cell lead 8, and the base container More power generating elements (active material 62) can be accommodated in the interior of the second unit. Further, since the cell 6 does not have a shape in which the vicinity of the fixed portion of the cell lead 8 is raised, more power generating elements (active material 62) can be stored inside the base container 2. As described above, by accommodating more power generation elements (active materials 62), it is possible to manufacture the electrochemical cell 1 that is small in size, has a large cell capacity, and has a low internal resistance.

(Second embodiment)
A second embodiment will be described based on FIGS. 24(A) and 24(B). The electrochemical cell 1 of the present embodiment has a base container 2 made of only a ceramic flat plate and a metal cavity-type lid 10a having a concave shape as an outer container, and FIG. A cross-sectional view is shown. As in the first embodiment, a unit 6u composed of upper and lower two-stage cells 6, a pair of cell leads 8 and an electrolyte 7 are housed inside the outer container, and are formed in the cell leads 8 and the base container 2. The formed pad film 5 is connected by welding.

By adopting the base container 2 made of only a ceramic flat plate, the unit 6u can be easily handled when the cell lead 8 is welded to the pad film 5. Specifically, in the case of the concave base container 2 of the first embodiment, as shown in FIGS. 8A and 8B, the unit 6u is placed outside the base container 2 because of the base wall portion 2b. The space for moving the ultrasonic welding tip 20 is limited because it is not moved. On the other hand, according to the present embodiment, since the base wall portion 2b does not exist in the base container 2, the unit 6u can be brought out of the base container 2 and the movement space of the ultrasonic welding tip 20 can be widened. You can This improves workability during welding. Moreover, since the length of the cell lead 8 can be shortened, the internal resistance can be reduced.

As shown in FIG. 24(A), the cavity-type lid 10a is welded so that the opening of the cavity-type lid 10a abuts a seal ring 9 provided around the base container 2 so as to cover the unit 6u and the like. Laser seam welding is preferred for this welding. Further, when seam welding is performed, scanning irradiation is performed from the direction of the arrow in FIG. In resistance seam welding using a roller electrode, the roller electrode is likely to come into contact with the step of the cavity type lid 10a, and it is difficult to bring the roller electrode into proper contact with the joint.

In the cavity type lid 10a, a small hole is provided in the bottom surface portion (upper end portion in the figure) of the cavity type lid 10a. This is intended to be able to fill the electrolyte 7 through this small hole after welding the base container 2 and the cavity-type lid 10a, and then to hermetically seal with the sealing plug 10b. As a result, it is possible to prevent a reduction in the efficiency of the sealing work due to the presence of the electrolyte 7 between the seal ring 9 and the bonding surface of the cavity lid 10a. The material of the pad film 5 formed on the inner surface of the base container 2, the range of the thickness thereof, the structure of the via wiring 3, the number thereof, and the means for joining the cell lead 8 and the pad film 5 are the same as those described above, and thus the description thereof is omitted. To do.

The electrochemical cell 1 shown in FIG. 24(B) has the same structure as that of FIG. 24(A), but the base container 2 is provided with a seal ring 9 arranged around the flat base container 2. The height difference between the seal ring 9 and the base bottom surface 2c is sufficiently small because it is fitted in the step. Accordingly, even if the unit 6u is placed in the cavity type lid 10a after the cavity type lid 10a is filled up with the electrolyte 7, the amount of the electrolyte overflowing from the cavity type lid 10a can be reduced. Therefore, with the configuration shown in FIG. 24B, the base container 2 and the cavity lid 10a can be easily welded even when the electrolyte 7 is filled. Therefore, the small hole of the cavity lid 10a as shown in FIG. 24(A) is not necessary, and the sealing step with the sealing plug 10b can be omitted.

(Third Embodiment)
A third embodiment will be described with reference to FIGS. 25 and 26A to 26D. FIG. 25 shows a perspective view of the base container 2 used in this embodiment. In the present embodiment, the base container 2 is composed of a ceramic flat plate and a metal cylindrical metal side wall 12 joined to the flat plate, thereby forming a concave container. A via wiring 3 that directly penetrates the base wall portion 2b is provided on the base bottom surface 2c of the base container 2, and a pair of pad films 5 are arranged thereon. The metal side wall 12 made of metal is selected so that the coefficient of thermal expansion matches that of the base container 2, and is joined to the flat plate with a brazing material. On the other hand, the opening on the opposite side forms the joint surface of the lid 10. In the present embodiment, the seal ring 9 for sealing the lid 10 is unnecessary, and the metal side wall 12 itself also serves as the seal ring 9. Therefore, at least the surface to be joined to the lid 10 is plated with nickel and gold, and the lid 10 is brought into contact with the plated surface and can be joined using resistance seam welding or laser seam welding. Is configured.

26A and 26B show cross-sectional views of the electrochemical cell 1 using the flat base container 2. A pair of cell leads 8 connected to each cell 6 are connected to the pad film 5 by welding means, and are connected to the connection terminal 4 by the via wiring 3. The outer container is filled with the electrolyte 7 and hermetically sealed by the lid 10. The material and thickness of the pad film are the same as those described above. Since the metal side wall 12 is made of metal, it can be processed into various shapes. The shape can be selected from corners, track shapes, ellipses, circles, and the like. In particular, when a standard hollow pipe is used after being cut to an arbitrary length, the height of the electrochemical cell 1 can be freely determined according to the height of the unit 6u, and the manufacturing cost can be reduced. be able to.

In the electrochemical cell 1 shown in FIGS. 26C and 26D, the metal side wall 12 made of metal is used as in FIGS. 26A and 26B, but the pad film 5 is provided only on the positive electrode side. This is a limited example. The positive electrode cell lead 8b is connected to the pad film 5 by ultrasonic welding, while the negative electrode cell lead 8c is connected to the inner side of the metal side wall 12 made of metal by welding. Further, the connection terminal 4 corresponding to the negative electrode 6c is configured to be electrically connected to the metal side wall. As a result, the metal side wall 12 is made of metal and the path through which the current flows is large, so that the wiring resistance value on the negative electrode side can be suppressed low. Therefore, the electrochemical cell 1 of the present embodiment can also discharge a large current.

(Fourth Embodiment)
A fourth embodiment will be described with reference to FIGS. 27A and 27B. FIG. 27A shows a cross section of the electrochemical cell 1. The base film 2c of the concave base container 2 made of ceramics is provided with the pad film 5 made of an aluminum film as described above, and the via wiring is formed. 3 is connected to the connection terminal 4. In the present embodiment, the via wiring 3 and the pad film 5 are provided only on the positive electrode side. Of the pair of cell leads 8 connected to each cell 6, the positive electrode cell lead 8b is connected to the pad film 5 by ultrasonic welding to realize a sufficiently low connection resistance value.

On the other hand, the negative electrode cell lead 8c has a structure connected to the inner surface side of the lid 10. Well-known welding such as ultrasonic welding, laser spot welding, resistance spot welding, and arc welding to the metallic lid 10 even when the material of the negative electrode cell lead 8c is made of aluminum, copper, or nickel thin plate or foil. It is possible to connect by law. Therefore, the connection resistance value can be suppressed to a sufficiently low value also on the negative electrode side.

The connection terminal 4 on the negative electrode side extends from the lower surface 2d of the base to the seal ring 9 along the side surface 2e of the base, and is electrically connected to the lid 10. The extended portion is referred to as an extended portion 4b. By adjusting the length, width and thickness of the conductor of the extended portion 4b, the direct current resistance value of the extended portion 4b can be suppressed to a low value, so that the wiring resistance value on the negative electrode side can be configured without being greatly increased.

The outer container is filled with the electrolyte 7, and the lid 10 is welded to the seal ring 9 to form an airtight container. In a lithium-ion secondary battery, a copper foil is commonly used as a negative electrode current collector material and a nickel thin plate is used as a cell lead, but the present embodiment can be applied. Therefore, a highly reliable small-sized and thin lithium-ion secondary battery having high airtightness can be manufactured.

The extended portion 4b is provided outside the container in the present embodiment. The connection between the lid 10 and the connection terminal 4 is not limited to this, and it is also easy to form a structure in which a hole is provided in the lower portion of the seal ring 9 and a conductor material is formed on the inner surface to connect to the connection terminal 4.

1 Electrochemical Cell 2 Base Container 2a Base Bottom 2b Base Wall 2c Base Bottom 2d Base Bottom 2e Base Side 3 Via Wiring 4 Connection Terminal 4b Extension 5 Pad Film 5a Welding 6 Cell 6a Separator 6b Positive Electrode 6c Negative 6u Unit 7 Electrolyte 8 Cell lead 8a Welding area 8b Positive electrode cell lead 8c Negative electrode cell lead 9 Seal ring 10 Lid 10a Cavity type lid 10b Sealing plug 12 Metal side wall 20 Ultrasonic welding tip 20a Tip tip 60 Electrode sheet 61 Base material 62 Active material 65 Bending portion 68 Winding core

Claims (3)

A base container,
An insulator , one electrode sheet, the insulator, and another electrode sheet are stacked in this order , and a cell housed in the base container,
Cell leads extending from opposite sides of each of the electrode sheets,
Made of a valve metal formed on the bottom surface of the base container, a pad film to which the cell lead of at least one of the pair of electrode sheets is connected,
In-base wiring connected to the pad film and formed on the bottom surface of the base container,
A seal ring joined to the upper surface of the base container,
An electrochemical cell having at least a lid bonded to an upper surface of the seal ring and closing the upper surface of the seal ring ,
In the cell, the other electrode sheets are folded inward so that the cell leads facing each other for each of the electrode sheets are overlapped with each other, and the insulator covers the outside, and the other electrode sheets are overlapped with each other. ,
An electrochemical cell, characterized in that a plurality of the cells selected from the cells having a plurality of different types of preset folding times are stored in the base container in a stacked state . A base container,
One electrode sheet, an insulator, and another electrode sheet are stacked in this order, and a cell housed in the base container,
Cell leads extending from opposite sides of each of the electrode sheets,
Made of a valve metal formed on the bottom surface of the base container, a pad film to which the cell lead of at least one of the pair of electrode sheets is connected,
In-base wiring connected to the pad film and formed on the bottom surface of the base container,
A seal ring joined to the upper surface of the base container,
An electrochemical cell having at least a lid bonded to an upper surface of the seal ring and closing the upper surface of the seal ring,
In the cell, the other electrode sheets are folded inward so that the cell leads facing each other for each electrode sheet are overlapped with each other, the one electrode sheet covers the outside, and the other electrode sheets are overlapped with each other. And
It is characterized in that a plurality of the cells selected from the cells having a plurality of different thicknesses with different preset folding numbers are stacked and housed in the base container in a state of being covered with the insulator. And an electrochemical cell. The electrode sheet is one in which an active material is fixed to a metal base material,
The electrochemical cell according to claim 1 or 2, wherein a plurality of the cells are stacked from a plurality of types of cells including the cells in which the layers formed by the active material have different thicknesses.