JP2012109250A - Electrochemical cell and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochemical cell of which the shape flexibility is enhanced, that can be smaller and thinner easily, that realizes the high capacity, and realizes low cost by reducing the number of man-hours.SOLUTION: The electrochemical cell includes: a base member 11 that is made up of a resin material and formed in a box-like shape; a first collector terminal 15 that is made up of a metal material and fixedly penetrates from the inner side to the outer side of the bottom of the box-like base member 11; a second collector terminal 16 that fixedly penetrates from the inner side to the outer side of the side part of the box-like base member 11; and a cover member 13 that is made up of a resin material deposited to the base member.

Description

  The present invention relates to a non-aqueous electrolyte battery, an electrochemical cell such as an electric double layer capacitor utilizing the electric double layer principle, and a method for producing the same.

  Electrochemical cells such as non-aqueous electrolyte batteries and electric double layer capacitors are used for backup power supplies for clock functions, backup power supplies for semiconductor memories, standby power supplies for electronic devices such as microcomputers and IC memories, batteries for solar clocks, and motor drives. Used as a power source. In recent years, the need for an electrochemical cell having a large capacity and current has been reduced due to non-volatile semiconductor memory and low power consumption of a timepiece functional element. Rather, as a need for electrochemical cells, high-density mounting is required together with ICs, crystals, SAW devices, etc., and a small and thin structure is required.

  Conventionally, electrochemical cells such as non-aqueous electrolyte batteries and electric double layer capacitors have been packaged in a metal case shaped like a coin or a button (see, for example, Patent Document 1).

  FIG. 8 is a cross-sectional view illustrating a conventional electrochemical cell. The positive electrode case 61 is formed via a stainless steel positive electrode case 61 having a circular opening on the upper end surface for accommodating the positive electrode active material 601, the negative electrode active material 603 and the separator 602 as electrodes, and a circular gasket 62 made of an insulating resin. It is comprised with the circular negative electrode case 63 which fits. In addition, when surface mounting is required, it has a positive terminal 65 a welded to the positive case 61 and a negative terminal 65 b welded to the negative case 63.

JP 2002-190427 A

  The conventional electrochemical cells such as the non-aqueous electrolyte battery and the electric double layer capacitor described above have a sealing structure that is crimped by crushing the annular gasket 62 with the positive electrode case 61 and the circular negative electrode case 63 opened in a circular shape. Was done. In order to ensure the sealing performance of the electrochemical cell, it was shaped like a coin or button. However, since packages such as ICs, crystals, and SAW devices arranged on the mounting substrate are square, a gap is generated when coin-type electrochemical cells are arranged. If this gap is used effectively, the storage capacity of the electrochemical cell can be expected to increase by more than 20%. Moreover, although the positive electrode case 61 is shape | molded with the metal material, since it will short-circuit if the negative electrode terminal 65b and the positive electrode case 61 contact, you must ensure a clearance gap. That is, as shown in FIG. 8, the negative electrode terminal 65b needs to protrude outside the outer diameter of the positive electrode case 61, and the occupied space on the mounting board is further increased. Therefore, when it is arranged on the mounting substrate, a dead space is generated and the occupied area is increased, and it is difficult to increase the capacity per unit area on the mounting substrate. Further, when the positive electrode terminal 65a and the negative electrode terminal 65b are attached to the positive electrode case 61 and the negative electrode case 63, since the respective components are overlapped and welded as shown in FIG. 12, the total thickness of the electrochemical cell is increased and the thickness is reduced. However, the number of steps for attaching the positive electrode and the negative electrode terminal has increased, and the cost has been increased.

  It is an object of the present invention to increase the degree of freedom of shape of an electrochemical cell, to facilitate downsizing and thinning, to realize a high capacity, to reduce the number of parts and man-hours, and to reduce the cost.

  In order to achieve the above object, the present invention provides a pair of electrodes made of a positive electrode active material and a negative electrode active material, a separator that separates the pair of electrodes, an electrolyte, and a box that houses the pair of electrodes and the electrolyte. An electrochemical cell composed of a base portion and a cover portion that seals the box-shaped base portion, wherein the box-shaped base portion and the cover portion are each made of a resin material, and one of the pair of electrodes is The first electrode is connected to a first current collecting terminal that is smaller than the other electrode and penetrates from the inside to the outside of the bottom of the box-shaped base portion, and the other electrode of the pair of electrodes is outside from the inside of the side portion of the box-shaped base portion. The second current collector terminal is connected to a second current collecting terminal penetrating through the terminal.

  Further, the box-shaped base portion has a step inside the side portion, the step is between the second current collecting terminal and the bottom of the box-shaped base portion, and the second current collecting terminal is above the step. It is characterized by being arranged.

  Moreover, the cover part and the box-shaped base part are sealed by welding.

  The resin material of the box-shaped base portion and the cover portion is any one of thermoplastic resin polyimide, polystyrene, polyphenylene sulfide, polyester, polyamide, and polyether.

  The cover portion is provided with an inlet through which an electrolyte can be injected, and the inlet is sealed by a stopper.

  Further, the first current collecting terminal and the second current collecting terminal are made of any one of stainless steel, aluminum, and an aluminum alloy.

  Moreover, a part of 1st current collection terminal and a part of 2nd current collection terminal are located on the same plane as the bottom part outer side of a box-shaped base part, It is characterized by the above-mentioned.

  The first current collector terminal is arranged in the mold so as to penetrate from the inside of the bottom of the box-shaped base portion to the outside, and the second current collector terminal is arranged from the inside of the side portion of the box-shaped base portion to the outside. A step of arranging in a molding die so as to penetrate; a step of injecting a resin material into the molding die to form a box-shaped base portion; and a pair of a positive electrode active material and a negative electrode active material for the first current collecting terminal Separating the electrode smaller than one of the other electrodes, connecting the other electrode of the pair of positive electrode active material and negative electrode active material to the second current collecting terminal, and separating the pair of electrodes The separator and the electrolyte are stored in a box-shaped base portion, and the cover portion is placed on the box-shaped base portion and sealed by laser welding or ultrasonic welding.

  Further, the first current collecting terminal and the second current collecting terminal are formed in a hoop.

  The operation of the above problem solving means is as follows. That is, an electrochemical cell having an arbitrary shape and sealing structure is realized by housing a pair of electrodes, a separator, and an electrolyte in a recess of a base member and overlapping and joining the cover member and the frame member.

  Further, the positive electrode and the negative electrode are connected to the mounting substrate by the first current collecting terminal and the second current collecting terminal. As a structure of the electrochemical cell, the base member insulates the first current collecting terminal and the second current collecting terminal. Therefore, the first current collecting terminal and the second current collecting terminal can be arranged on the lower end surface of the base member, and the dead space on the mounting substrate can be minimized and the capacity can be increased.

  Further, since the frame connection terminal has a structure extending from the frame member or the cover member, the thickness is reduced without increasing the total thickness of the electrochemical cell. The man-hour for attaching a positive electrode and a negative electrode terminal is also unnecessary.

  As described above, the present invention increases the degree of freedom of shape of the electrochemical cell, facilitates downsizing and thinning, realizes high capacity, and reduces the number of parts and man-hours, thereby reducing the cost. It is.

It is a block diagram of the electrochemical cell of this invention. It is an external view of the electrochemical cell of this invention. It is sectional drawing of the electrochemical cell of this invention. It is an external view of the electrochemical cell of this invention. It is sectional drawing of the electrochemical cell of this invention. It is a flowchart explaining the manufacturing method of the electrochemical cell of this invention. It is an external view explaining the manufacturing method of the electrochemical cell of this invention. It is sectional drawing of the conventional electrochemical cell.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  In FIGS. 1, 2, and 3, reference numeral 11 denotes a base member made of a resin material formed in a box shape having a recess 11 a, which penetrates the wall surface of the base member 11 from the inside to the outside of the recess 11 a of the base member 11. The first and second current collecting terminals 15 and 16 constitute a container. In addition, the positive electrode active material 101 and the first current collecting terminal 15 are bonded together with a conductive adhesive, and the separator 102 is accommodated in the recess 11a so as to overlap the positive electrode active material 101, and the negative electrode active material 102 and the second current collector terminal 15 are stored. The electrical terminals 16 are bonded together with a conductive adhesive and accommodate an electrolyte (not shown). Further, the base member 11 and the cover member 13 are overlapped and welded. The first current collecting terminal 15 and the second current collecting terminal 16 are made of stainless steel or aluminum.

  Here, as a configuration of the current collecting terminal, a configuration in which the second current collecting terminal is placed on the cover member is also used.

  In addition, as the material of the current collecting terminal, a metal suitable for pressability and machinability is used from aluminum, aluminum alloy, etc., such as 19Cr-9Ni steel and 18Cr-12Ni-Mo-Cu steel, in the case of stainless steel. Further, a configuration in which the first current collecting terminal is made of stainless steel and the second current collecting terminal is made of aluminum or an aluminum alloy, or a configuration in the opposite combination is also used. The cover member and the base member can be welded by using a light absorption method such as a YAG laser or a semiconductor laser, or by pressing an ultrasonic vibrator against the cover member and rubbing it between the base member and frictional heat. The method using is used.

  The material of the base member is an insulating resin, and polystyrene-based, polyphenylene sulfide-based, polyester-based, polyamide-based, and polyether-based thermoplastic resins are suitable in terms of weldability, rigidity, and heat resistance. Here, syndiotactic polystyrene is used as the polystyrene system, linear and cross-linked polyphenylene sulfide is used as the polyphenylene sulfide system, wholly aromatic polyester is called liquid crystal polymer as the polyester system, nylon is used as the polyamide system, and polyether is used as the polyether system Polyether ether ketone, polyether sulfone, polyether imide, etc. are selected. Further, those obtained by adding glass fiber, mica, ceramic fine powder, etc. to these resins are also used.

  In addition, as a power generation element of an electrochemical cell housed in a container composed of a base member, a first current collecting terminal, and a second current collecting terminal, a lithium-containing manganese is used as a positive electrode active material if it is a nonaqueous electrolyte battery. As oxides, lithium-containing cobalt oxides, lithium-containing titanium oxides, and negative electrode active materials, conventionally known materials such as carbon, lithium alloys, transition metal oxides, and silicon oxides can be used. In the electric double layer capacitor, activated carbon can be used for the positive electrode and the negative electrode active material.

  In addition, as the separator, an insulating film having a large ion permeability and a predetermined mechanical strength is used, and glass fiber can be used stably. Polyphenylene sulfide, polyethylene terephthalate, polyamide, polyimide, Resin can also be used. The pore diameter and thickness of the separator are not particularly limited, but are design matters determined based on the current value of the equipment used and the internal resistance of the electrochemical cell. A ceramic porous body can also be used.

  As the solvent for the electrolytic solution, when an electric double layer capacitor or a non-aqueous secondary battery is taken as an example, a conventional non-aqueous solvent is used. This non-aqueous solvent includes cyclic esters, chain esters, cyclic ethers, chain ethers, and the like. Considering reflow mounting, it can be used alone or in combination selected from γ-butyrolactone (γBL), propylene carbonate (PC), ethylene carbonate (EC), and the like.

As the electrolyte, (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 One or more salts such as lithium salt such as aluminum fluoride and the like can be used. Polyethylene oxide derivatives or polymers containing polyethylene oxide derivatives, polymers containing polypropylene oxide derivatives and polypropylene oxide derivatives, phosphate ester polymers, PVDF, etc., used in combination with nonaqueous solvents and supporting salts, including gel or solid use . Also it includes the use of an inorganic solid electrolyte _{LiS / SiS 2 / Li 4 SiO} 4. Also, pyridine-based, alicyclic amine-based, aliphatic amine-based ionic liquids and amidine-based room temperature molten salts may be used.

  In the embodiment of the present invention, the joints between the base member 11 and the first current collecting terminal 15 and the second current collecting terminal 16 are in close contact regardless of the shape, and the base member 11 and the cover member 13 are Since sealing performance by resin welding can be obtained, there is no restriction on the shape. That is, even if the base member 11 is a rectangular box-shaped storage container, moisture from the outside can be prevented and the characteristics of the electrochemical cell can be maintained.

  In the embodiment, a planar mounting type mounting example will be described. However, an insertion type mounting that is inserted into a through hole and mounted, and a mounting form by contact using a holder are also possible.

  FIG. 1 shows a configuration diagram of the electrochemical cell of the present invention. Moreover, the external view of the electrochemical cell of this invention is shown in FIG. FIG. 3 shows a cross-sectional view of the electrochemical cell of the present invention.

In this embodiment, the base member 11 is made of polyphenylene sulfide, and the first current collecting terminal 15 and the second current collecting terminal 16 are made of stainless 18Cr-12Ni—Mo—Cu steel. Further, a configuration in which a portion where the first current collecting terminal 15 extends to the outer wall of the base member 11 and a portion where the second current collecting terminal 16 extends to the outer wall of the base member 11 are located on the same plane. did. Further, the portions where the first current collecting terminal 15 and the second current collecting terminal 16 extend to the outer wall of the base member 11 were subjected to tin plating in order to facilitate solder bonding with the mounting substrate. The active material was prepared by kneading carbon black as a conductive agent and PTFE as a binder in commercially available activated carbon. The kneaded product was rolled into a sheet by a roll press, and cut into a positive electrode active material 101 and a negative electrode active material 103. The electrolyte used was (C ₂ H ₅ ) ₄ NBF ₄ dissolved in PC. Here, as an assembling method of the electrochemical cell, the first current collecting terminal 15 and the second current collecting terminal 16 are arranged in the base member mold, and a box shape having a recess 11a by injecting polyphenylene sulfide resin. The base member 11 is formed. After the first current collecting terminal 15 and the positive electrode active material 101 are adhered, the separator 102 is accommodated in the recess 11a, the negative electrode active material 103 is accommodated in the recess 11a, and is adhered to the second current collecting terminal, and the electrolyte is provided in the recess 11a. Injected. Next, the base member 11 and the cover member 13 were overlapped, and ultrasonic welding of the friction heating method was performed.

In order to evaluate the sealing performance of the electrochemical cell, a leak test was performed by immersion in a fluorine-based liquid, and it was confirmed that the sealing performance was 10 ⁻⁵ atm · cc / sec or more. The electrochemical cell was soldered through a reflow oven with a preheating of 140 ° C for 1 minute, a main heating time of 220 ° C or more for 20 seconds and a peak temperature of 240 ° C before and after soldering. It was confirmed that there was no change in characteristics.

  FIG. 4 shows an external view of the electrochemical cell of the present invention. FIG. 5 shows a cross-sectional view of the electrochemical cell of the present invention.

The base member 31 is made of polyphenylene sulfide, and the first current collecting terminal 35 and the second current collecting terminal 36 are made of stainless 18Cr-12Ni—Mo—Cu steel. Further, a configuration in which a portion where the first current collecting terminal 15 extends to the outer wall of the base member 11 and a portion where the second current collecting terminal 16 extends to the outer wall of the base member 11 are located on the same plane. did. Further, tin plating was applied to the portion where the first current collecting terminal 35 and the second current collecting terminal 36 extend to the outer wall of the base member 31 in order to facilitate solder bonding with the mounting substrate. In addition, an injection port 33 a is provided in the cover member 33, and after the cover member 33 is welded to the base member 31, an electrolyte is injected and sealed with a plug member 37. The active material was prepared by kneading carbon black as a conductive agent and PTFE as a binder in commercially available activated carbon. The kneaded material was rolled with a roll press to form a sheet, and cut into a positive electrode active material 301 and a negative electrode active material 303. The electrolyte used was (C ₂ H ₅ ) ₄ NBF ₄ dissolved in PC. Here, as an assembling method of the electrochemical cell, the first current collecting terminal 35 and the second current collecting terminal 36 are arranged in the base member molding die, and a box shape having a recess 31a by injecting polyphenylene sulfide resin. The base member 31 is formed. After bonding the first current collecting terminal 35 and the positive electrode active material 301, the separator 302 was placed in the recess 31a, and the second current collecting terminal 36 and the negative electrode active material 303 were bonded. Next, after superposing the base member 31 and the cover member 33 and performing ultrasonic welding by the friction heating method, the electrolyte is injected from the injection port 33a, the injection port 33a and the plug member 37 are fitted, and the plug member 38 is attached. Sealing was performed by heat welding.

In order to evaluate the sealing performance of the electrochemical cell, a leak test was performed by immersion in a fluorine-based liquid, and it was confirmed that the sealing performance was 10 ⁻⁵ atm · cc / sec or more. The electrochemical cell was soldered through a reflow oven with a preheating of 140 ° C for 1 minute, a main heating time of 220 ° C or more for 20 seconds and a peak temperature of 240 ° C before and after soldering. It was confirmed that there was no change in characteristics.

  FIG. 6 shows a flow chart for explaining the method for producing an electrochemical cell of the present invention. Moreover, the external view explaining the manufacturing method of the electrochemical cell of this invention is shown in FIG.

  The first current collecting terminal 55 and the second current collecting terminal 56 formed in the hoop are disposed in the base member mold (step 301). Next, a resin material is injected into the base member molding die to mold the base member 51 into a box shape having a recess 51a, and is assembled as a first current collecting terminal 55 and a second current collecting terminal 56 container (steps) 302). Next, the pair of electrodes, the separator, and the electrolyte are accommodated in the recess 51a of the base member (step 303). The base member 51 and a cover member (not shown) are overlapped and welded (step 304).

  Here, the 1st current collection terminal 55 and the 2nd current collection terminal 56 were pressed using the thin plate of stainless 18Cr-12Ni-Mo-Cu steel, and the hoop was produced. In the press work, the feed hole 59 used for positioning the workpiece in each process is processed, and the window is left leaving the bridge 58 for holding the first current collecting terminal 55 and the second current collecting terminal 56. It was. The resin material for the base member 51 is polyphenylene sulfide. The thermoplastic resin polyphenylene sulfide was injection molded using a base member mold. At this time, the first current collecting terminal 55 and the second current collecting terminal 56 arranged in the base member molding die are in close contact with the polyphenylene sulfide of the base member 51 and can be molded into a desired shape. Further, polyphenylene sulfide was used as the resin material for the cover member. The thermoplastic resin polyphenylene sulfide was injection molded using a cover member mold.

  For joining the base member 51 and the cover member, ultrasonic welding was used. Specifically, the ultrasonic vibrator was pressed against the cover member evenly to vibrate. The resin on the contact surface between the base member 51 and the cover member generates heat due to friction and melts. By stopping the ultrasonic vibration, the molten resin is cooled and solidified, and the base member 51 and the cover member are joined.

After this welding, the bridge 58 connected to the frame member 52 was cut off from the hoop to produce an electrochemical cell. In order to evaluate the sealing performance of the electrochemical cell, a leak test was performed by immersion in a fluorine-based liquid, and it was confirmed that the sealing performance was 10 ⁻⁵ atm · cc / sec or more. The electrochemical cell was soldered through a reflow oven with a preheating of 140 ° C for 1 minute, a main heating time of 220 ° C or more for 20 seconds and a peak temperature of 240 ° C before and after soldering. It was confirmed that there was no change in characteristics.

11, 31, 51 Base members 12, 32, 52 Frame members 13, 33 Cover members 15, 35, 55 First current collecting terminals 16, 36, 56 Second current collecting terminals 61 Positive electrode can 62 Gasket 63 Negative electrode can 65a Positive electrode terminal 65b Negative electrode terminal 601 Positive electrode 602 Separator 603 Negative electrode

Claims (9)

A pair of electrodes composed of a positive electrode active material and a negative electrode active material; a separator separating the pair of electrodes; an electrolyte; a box-shaped base portion housing the pair of electrodes and the electrolyte; and the box-shaped base portion. An electrochemical cell comprising a cover part to be sealed,
The box-shaped base part and the cover part are each made of a resin material,
One electrode of the pair of electrodes is smaller than the other electrode and connected to the first current collecting terminal penetrating from the inside of the bottom of the box-shaped base portion to the outside,
The other electrode of the pair of electrodes is connected to a second current collecting terminal penetrating from the inner side to the outer side of the box-shaped base portion. The box-shaped base portion has a step on the inner side,
The step is between the second current collecting terminal and the bottom of the box-shaped base portion,
The electrochemical cell according to claim 1, wherein the second current collecting terminal is disposed on the step.   The electrochemical cell according to claim 1, wherein the cover part and the box-shaped base part are sealed by welding.   The resin material of the box-shaped base portion and the cover portion is any one of thermoplastic resin polyimide-based, polystyrene-based, polyphenylene sulfide-based, polyester-based, polyamide-based, and polyether-based. 4. The electrochemical cell according to any one of 3. The cover part is provided with an inlet through which the electrolyte can be injected,
The electrochemical cell according to any one of claims 1 to 4, wherein the injection port is sealed by a stopper.   The electrochemical cell according to any one of claims 1 to 5, wherein the first current collecting terminal and the second current collecting terminal are made of any one of stainless steel, aluminum, and an aluminum alloy. .   The part of said 1st current collection terminal and a part of said 2nd current collection terminal are located on the same plane as the bottom part outer side of a box-shaped base part, The one of Claim 1 to 6 characterized by the above-mentioned. The electrochemical cell according to 1. The first current collector terminal is disposed in the mold so as to penetrate from the inside of the bottom of the box-shaped base portion to the outside, and the second current collector terminal penetrates from the inside of the side portion of the box-shaped base portion to the outside. Arranging in the mold so as to
Injecting a resin material into the mold and molding the box-shaped base portion;
Connecting one of a pair of electrodes made of a positive electrode active material and a negative electrode active material to the first current collecting terminal, the electrode being smaller than the other electrode;
Connecting the other electrode of the pair of electrodes made of a positive electrode active material and a negative electrode active material to the second current collecting terminal;
Storing the separator separating the pair of electrodes and the electrolyte in the box-shaped base portion;
Placing the cover portion on the box-shaped base portion, and sealing with laser welding or ultrasonic welding.   The method for producing an electrochemical cell according to claim 8, wherein the first current collecting terminal and the second current collecting terminal are formed in a hoop.

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