JP2009076248A - Power storage device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance productivity of a power storage device by applying effective technique to the power storage device pouring an electrolyte into an outer packaging film. <P>SOLUTION: The power storage device 10 has a unit housing part 11a for housing a three-electrode laminating unit (an electrode unit) 17; an upper side part 11c positioning in the upper part of the unit housing part 11a in electrolyte pouring; a side part 11e positioning in the side of the unit housing part in electrolyte pouring; and a storage part 11b positioning between the unit housing part 11a and a lower side part 11d, formed in a laminate film (an outer packaging film) 11, and after the lower side part 11d and the side part 11e are sealed, an electrolyte is poured from the upper side part 11c, the electrolyte is stored in the storage part 11b in the lower part of the thee-electrode laminating unit 17, and then the upper side part 11c is sealed, thereby, air can be removed from the laminate film 11 without overflow of the electrolyte. Productivity of the power storage device 10 can be thus enhanced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique effective when applied to an electricity storage device in which an electrolytic solution is injected into an exterior film.

  Electric vehicles, hybrid vehicles, and the like are equipped with power storage devices such as lithium ion secondary batteries and electric double layer capacitors. Since these power storage devices are required to be reduced in size and weight, a laminate-type power storage device that employs a laminate film as an outer container has been proposed. When manufacturing this laminate-type electricity storage device, after sandwiching the electrode unit between a pair of laminate films, the outer peripheral portion of the laminate film is sealed over three sides. Then, after injecting a specified amount of electrolyte into the bag-shaped laminate film, the remaining one side is sealed in a vacuum atmosphere.

  By the way, from the viewpoint of increasing the capacity and miniaturization of the electricity storage device, the electrodes constituting the electrode unit tend to be laminated densely, or the gap between the electrode unit and the laminate film tends to be narrowed. However, assembling the electrode units closely causes a decrease in the permeability of the electrolyte solution to the electrode units, and reducing the gap between the electrode unit and the laminate film means that the electrolyte solution that can be injected into the electricity storage device at a time. It was a factor to reduce the amount. That is, in order to inject a specified amount of electrolyte, it is necessary to inject a small amount of electrolyte multiple times. In such a manufacturing method, the injection of electrolyte becomes longer as the injection time of the electrolyte increases. Not only does the amount easily vary, but also moisture in the air dissolves in the electrolyte, which causes a reduction in the withstand voltage of the electricity storage device.

In view of this, an electricity storage device has been proposed in which a laminate film is cut out longer and the upper part of the electrode unit is used as a liquid storage part (see, for example, Patent Document 1). According to this electricity storage device, it is possible to inject a specified amount of electrolyte at a time, and it is possible to immediately seal the laminate film after injecting the electrolyte, thus reducing the number of manufacturing steps. Thus, it is possible to suppress deterioration of the electrolytic solution.
JP 2000-311661 A

  However, in the method for manufacturing an electricity storage device described in Patent Document 1, since the upper part of the electrode unit is used as a liquid storage part, there is a problem that the electrolyte easily overflows when the electricity storage device is arranged in a vacuum atmosphere. There is. That is, since the electrolyte is stored above the electrode unit, when the electricity storage device is placed in a vacuum atmosphere and the air in the laminate film is extracted, the electrolyte overflows with the air discharged from the laminate film. There is a risk that. Such leakage of the electrolyte has been a factor that reduces the productivity of the electricity storage device.

  An object of the present invention is to improve the productivity of an electricity storage device.

  The method for producing an electricity storage device of the present invention is a method for producing an electricity storage device comprising an electrode unit comprising a positive electrode and a negative electrode, and an exterior film that is accommodated with the electrode unit sandwiched therebetween, wherein the electrode unit comprises: A unit accommodating portion to be accommodated, a lower side portion located below the unit accommodating portion when electrolyte solution is injected, an upper side portion located above the unit accommodating portion when electrolyte solution is injected, and the unit accommodating portion when electrolyte solution is injected Forming a side part located on the side of the container and a storage part located between the unit housing part and the lower side part, sealing the lower side part and the side part, and then supplying an electrolytic solution from the upper side part And the upper side portion is sealed under a state in which the electrolytic solution is stored in the storage portion below the electrode unit.

  In the method for manufacturing an electricity storage device of the present invention, an electrolyte is injected from the upper side under a first pressure atmosphere, and the upper side is sealed under a second pressure atmosphere lower in pressure than the first pressure atmosphere. Features.

  An electricity storage device of the present invention is an electricity storage device having an electrode unit including a positive electrode and a negative electrode, and an exterior film that is accommodated with the electrode unit interposed therebetween, wherein the exterior film is a unit accommodation portion in which the electrode unit is accommodated. And a lower side portion located below the unit housing portion when the electrolyte solution is injected, an upper side portion located above the unit housing portion when the electrolyte solution is injected, and a side portion of the unit housing portion when the electrolyte solution is injected. Forming a side part and a storage part located between the unit housing part and the lower side part, and after the lower side part and the side part are sealed, an electrolyte is injected from the upper side part, The upper side portion is sealed under a state in which an electrolytic solution is stored in the storage portion below the electrode unit.

  The electricity storage device of the present invention is characterized in that an electrolyte is injected from the upper side under a first pressure atmosphere, and the upper side is sealed under a second pressure atmosphere lower in pressure than the first pressure atmosphere. To do.

  The electricity storage device according to the present invention is characterized in that, after the electrode unit is impregnated with the electrolytic solution in the storage part, the storage part functions as a gas storage part in an abnormal state.

  The electricity storage device of the present invention is characterized in that the capacity of the reservoir is set to be less than the injection amount of the electrolyte.

  The electricity storage device of the present invention is characterized in that the electrolytic solution is an aprotic organic solvent.

The electricity storage device of the present invention is characterized in that a positive electrode potential when the positive electrode and the negative electrode are short-circuited is 2 V (vs. Li / Li ⁺ ) or less.

  The electricity storage device of the present invention has a lithium ion supply source that is short-circuited to at least one of the negative electrode and the positive electrode, forms a through-hole through which lithium ions pass through a current collector provided in the positive electrode and the negative electrode, One of the negative electrode and the positive electrode is doped with lithium ions from the lithium ion supply source.

  According to the present invention, the exterior film has a unit housing portion in which the electrode unit is housed, a lower side portion located below the unit housing portion when the electrolyte is injected, and an upper side located above the unit housing portion when the electrolyte is injected. And a storage part located between the unit accommodation part and the lower side part, and the lower side part and the side part are sealed. Later, the electrolyte is injected from the upper side, and the upper side is sealed under the condition that the electrolyte is stored in the storage part below the electrode unit. Therefore, the electrolyte leaks even if the electricity storage device is placed in a vacuum atmosphere. There is nothing. Thereby, it becomes possible to improve productivity of an electrical storage device. In addition, since the time from the injection of the electrolytic solution to the sealing is short, the amount of moisture absorbed in the assembly process can be reduced, so that the performance of the electricity storage device can be improved.

  FIG. 1 is a perspective view showing an electricity storage device 10 according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view showing an internal structure of the electricity storage device 10. As shown in FIGS. 1 and 2, the electricity storage device 10 includes a pair of laminate films (exterior films) 11 that are accommodated with an electrode laminate unit 12 interposed therebetween. As this laminate film 11, a three-layer laminate film having a nylon film on the outside, an aluminum foil in the center, and an adhesive layer on the inside is employed. Moreover, the laminate film 11 is formed with a deep drawing process of a unit accommodation portion 11a for accommodating the electrode lamination unit 12 and a storage portion 11b adjacent to the unit accommodation portion 11a. Further, the laminate film 11 is formed with an upper side part 11c, a lower side part 11d, and a side part 11e which are subjected to a heat-sealing process after being accommodated with the electrode laminated unit 12 interposed therebetween. In addition, it is preferable to set the capacity | capacitance of the storage part 11b below the injection amount of electrolyte solution from a viewpoint of improving volumetric efficiency, as shown in the figure.

  3 is a cross-sectional view showing the internal structure of the electricity storage device 10, and FIG. 4 is a cross-sectional view showing the internal structure of the electricity storage device 10 partially enlarged. First, as shown in FIG. 3, the electrode lamination unit 12 accommodated in the laminate film 11 is composed of positive electrodes 14 and negative electrodes 15 that are alternately laminated via separators 13. A lithium electrode (lithium ion supply source) 16 is disposed on the outermost part of the electrode laminate unit 12 so as to face the negative electrode 15, and the electrode laminate unit 12 and the lithium electrode 16 constitute a three-electrode laminate unit (electrode unit) 17. Is configured. Note that an electrolyte solution made of an aprotic organic solvent containing a lithium salt is injected into the laminate film 11.

  As shown in FIG. 4, the positive electrode 14 includes a positive electrode current collector 14b having a large number of through holes 14a, and a positive electrode mixture layer 14c applied to the positive electrode current collector 14b. The negative electrode 15 includes a negative electrode current collector 15b having a large number of through holes 15a and a negative electrode mixture layer 15c applied to the negative electrode current collector 15b. A plurality of positive electrode current collectors 14b connected to each other are connected to positive electrode terminals 18 protruding from the laminate film 11, and a plurality of negative electrode current collectors 15b connected to each other are protruded from the laminate film 11. A negative electrode terminal 19 is connected. Further, the lithium electrode 16 disposed at the outermost part of the electrode laminate unit 12 is composed of a lithium electrode current collector 16a made of a conductive porous material such as stainless steel mesh, and metal lithium 16b attached thereto. The lithium electrode current collector 16a is connected to the negative electrode current collector 15b.

The positive electrode mixture layer 14c of the positive electrode 14 contains activated carbon as a positive electrode active material capable of reversibly doping / dedoping lithium ions (hereinafter referred to as doping / dedoping). The negative electrode mixture layer 15c of the negative electrode 15 contains non-graphitizable carbon powder as a negative electrode active material capable of reversibly doping and dedoping lithium ions. That is, the power storage device 10 shown in the figure is a lithium ion capacitor that combines a power storage mechanism of a lithium ion secondary battery and an electric double layer capacitor. Further, the negative electrode 15 is pre-doped with lithium ions from the lithium electrode 16 to lower the negative electrode potential and improve the energy density. Here, from the viewpoint of improving the capacity of the electricity storage device 10, lithium ions are applied to the negative electrode so that the positive electrode potential after the positive electrode 14 and the negative electrode 15 are short-circuited is 2 V (vs. Li / Li ⁺ ) or less. It is preferable to dope.

  As shown in FIG. 3, since the negative electrode 15 and the lithium electrode 16 are short-circuited, doping of lithium ions into the negative electrode 15 is started by injecting electrolyte into the laminate film. The positive electrode current collector 14b and the negative electrode current collector 15b are formed with a large number of through holes 14a and 15a, and lithium ions released from the lithium electrode 16 move to each electrode through the through holes 14a and 15a. It becomes possible to do. Thereby, it is possible to dope lithium ions smoothly to all the negative electrode mixture layers 15c to be laminated without causing the lithium electrodes 16 to face the negative electrodes 15. In the present invention, “doping” means occlusion, support, adsorption, insertion, etc., and means a state in which lithium ions, anions, and the like are emitted from the positive electrode active material and the negative electrode active material. .

  Then, the manufacturing method of the electrical storage device 10 which is one embodiment of this invention is demonstrated. 5-7 is explanatory drawing which shows the manufacturing method of the electrical storage device 10. FIG.

  First, as shown in FIG. 2, the three-pole laminated unit 17 is accommodated in the laminate film 11 so as to be sandwiched between the unit accommodating portions 11 a of the laminate film 11. Next, as shown in FIG. 5, the lower side part 11 d located on the storage part 11 b side and the side part 11 e from which the terminal protrudes are subjected to heat fusion treatment, and the laminate film 11 is opened only at the upper side part 11 c. It will be formed in the bag shape. Subsequently, the electricity storage device 10 is installed so that the lower side portion 11d of the laminate film 11 is positioned below the three-pole laminated unit 17, and a specified amount of electrolysis is performed from the upper side portion 11c in an atmospheric pressure atmosphere (first pressure atmosphere). The liquid is injected into the laminate film 11. The injected electrolytic solution passes between the three-pole laminated unit 17 and the laminate film 11 and flows into the storage portion 11 b located below the three-pole laminated unit 17.

  Thus, since the storage part 11b was formed with respect to the laminate film 11, it becomes possible to inject | pour into the laminate film 11 the electrolyte solution of the defined amount defined by the design at once. Thereby, it is possible to complete the injection operation of the electrolytic solution without waiting for the penetration of the electrolytic solution into the three-pole laminated unit 17, and it is possible to quickly move to the next step. In addition, since dope of lithium ion is started by injection | pouring of electrolyte solution, in order to dope lithium ion uniformly, it is preferable to pinch the electrical storage device 10 with a pressure plate.

  Subsequently, the electricity storage device 10 is accommodated in a vacuum fusion machine (not shown), and the air in the laminate film 11 is removed in a vacuum atmosphere (second pressure atmosphere) lower than atmospheric pressure as shown in FIG. After that, as shown in FIG. 7, the heat bonding process is performed on the upper side portion 11 c of the laminate film 11. Here, if a structure in which the storage portion 11b is formed above the unit housing portion 11a and the electrolytic solution is stored above the three-pole laminated unit 17 is employed, the air contained in the three-pole laminated unit 17 in a vacuum atmosphere There is a possibility that the electrolyte solution pushed up by bubbles due to expansion by depressurization or defoaming will overflow from the laminate film 11 when removing. However, in the electricity storage device 10 of the present invention, since the storage portion 11b is formed below the unit housing portion 11a and the electrolytic solution is stored below the three-pole laminated unit 17, the electrolytic solution is overflowed. Therefore, air can be extracted from the laminate film 11.

  Thus, since the storage part 11b was formed so that it might be located under the unit accommodating part 11a at the time of electrolyte solution injection | pouring, while being able to inject | pour specified amount electrolyte solution into the laminate film 11 at once, Since the air in the laminate film 11 can be extracted without overflowing the electrolytic solution after the injection of the liquid, the productivity of the electricity storage device 10 can be improved and the manufacturing cost can be reduced. Moreover, since the upper side portion 11c can be sealed by removing air from the laminate film 11 after the electrolyte solution is injected, the time during which the electrolyte solution is exposed to the air can be shortened, and the air dissolved in the electrolyte solution It becomes possible to reduce the water content of the as much as possible. Accordingly, since the electrolytic solution can be stabilized in a wide potential range, gas generation due to water electrolysis can be suppressed, and durability of the electricity storage device 10 can be improved.

  Further, as time passes, the electrolytic solution penetrates into the three-pole laminated unit 17 and the electrolytic solution is discharged from the storage portion 11b. However, as shown in FIG. You may use the electrical storage device 10 with leaving. As described above, when the storage unit 11b is left in the power storage device 10, the gas is guided to the storage unit 11b functioning as a gas storage unit even when the electrolyte is decomposed due to overcharge or the like and gas is generated. Therefore, the laminate film 11 can be prevented from rupturing and the safety of the electricity storage device 10 can be improved. On the other hand, the storage unit 11 b may be separated from the electricity storage device 10 after the electrolytic solution in the storage unit 11 b has permeated the three-pole laminated unit 17. Here, FIGS. 8A and 8B are explanatory diagrams illustrating a procedure when the storage unit 11 b is separated from the power storage device 10. As illustrated in FIGS. 8A and 8B, when the storage unit 11 b is separated from the power storage device 10, heat fusion is performed on the boundary portion between the unit storage unit 11 a and the storage unit 11 b of the laminate film 11. After the landing process is performed, the storage unit 11b is disconnected from the power storage device 10. In this way, it is possible to reduce the size of the electricity storage device 10 by separating the storage portion 11b.

  Hereinafter, the components of the electricity storage device 10 described above will be described in the following order. [A] negative electrode, [B] positive electrode, [C] negative electrode current collector and positive electrode current collector, [D] separator, [E] electrolyte solution, [F] laminate film.

[A] Negative Electrode The negative electrode 15 has a negative electrode current collector 15b and a negative electrode mixture layer 15c integrated therewith, and the negative electrode mixture layer 15c contains a negative electrode active material. The negative electrode active material is not particularly limited as long as ions can be reversibly doped / dedoped, and examples thereof include graphite, various carbon materials, polyacene-based materials, tin oxide, and silicon oxide. In particular, graphite and non-graphitizable carbon are suitable as a negative electrode active material because the capacity can be increased.

  The negative electrode active material such as PAS described above is formed into a powder form, a granular form, a short fiber form, etc., and this negative electrode active material is mixed with a binder to form a slurry. And the negative electrode active material layer 15c is formed on the negative electrode collector 15b by apply | coating the slurry containing a negative electrode active material to the negative electrode collector 15b, and making it dry. Examples of the binder mixed with the negative electrode active material include fluorine-containing resins such as polytetrafluoroethylene and polyvinylidene fluoride, thermoplastic resins such as polypropylene, polyethylene, and polyacrylate, and styrene butadiene rubber (SBR). Examples thereof include rubber-based binders, and among these, fluorine-based binders are preferably used. As this fluorine-type binder, a polyvinylidene fluoride, a vinylidene fluoride-trifluoride ethylene copolymer, an ethylene-tetrafluoroethylene copolymer, a propylene-tetrafluoroethylene copolymer etc. are mentioned, for example. Moreover, you may make it add electroconductive materials, such as acetylene black, a graphite, and a metal powder, suitably with respect to the negative mix layer 15c.

[B] Positive Electrode The positive electrode 14 has a positive electrode current collector 14b and a positive electrode mixture layer 14c integrated therewith, and the positive electrode mixture layer 14c contains a positive electrode active material. The positive electrode active material is not particularly limited as long as it is capable of reversibly doping and dedoping ions, and examples thereof include activated carbon, transition metal oxides, conductive polymers, and polyacene-based materials. The activated carbon contained as the positive electrode active material in the positive electrode mixture layer 14c described above is formed from activated carbon particles that have been subjected to an alkali activation treatment and have a specific surface area of 600 m ² / g or more. As the raw material for the activated carbon, phenol resin, petroleum pitch, petroleum coke, coconut shell, coal-based coke and the like are used, and phenol resin and coal-based coke are preferable from the viewpoint of increasing the specific surface area.

Alternatively, the above-described positive electrode mixture layer 14c may contain lithium cobalt oxide (LiCoO ₂ ) as a positive electrode active material, thereby causing the electricity storage device 10 to function as a lithium ion secondary battery. In addition to these, Li _x M _y O _z such as Li _x CoO ₂ , Li _x NiO ₂ , Li _x MnO ₂ , and Li _x FeO ₂ (x, y, z are positive numbers, M is a metal, 2 It is also possible to contain a lithium-containing metal oxide that can be represented by the general formula (which may be a metal of more than one species), or a transition metal oxide or sulfide such as cobalt, manganese, vanadium, titanium, nickel. In particular, when a high voltage is required, lithium-containing cobalt oxide, lithium-containing nickel oxide, or lithium-containing cobalt-nickel composite oxide having a potential of 4 V or more with respect to metallic lithium is particularly suitable.

  A positive electrode active material such as activated carbon or lithium cobaltate is formed into a powder form, a granular form, a short fiber form, and the like, and the positive electrode active material is mixed as a binder to form a slurry. Then, the positive electrode active material layer 14c is formed on the positive electrode current collector 14b by applying the slurry containing the positive electrode active material to the positive electrode current collector 14b and drying it. Examples of the binder mixed with the positive electrode active material include rubber-based binders such as SBR, fluorine-containing resins such as polytetrafluoroethylene and polyvinylidene fluoride, and thermoplastic resins such as polypropylene, polyethylene, and polyacrylate. It is done. Moreover, you may make it add electrically conductive materials, such as acetylene black, a graphite, and a metal powder, with respect to the positive mix layer 14c.

[C] Negative electrode current collector and positive electrode current collector The negative electrode current collector 15b and the positive electrode current collector 14b are preferably provided with through holes 14a and 15a penetrating the front and back surfaces, for example, expanded metal, punching A metal, a net | network, a foam, etc. are mentioned. The shape and number of the through holes 14a and 15a are not particularly limited, and can be appropriately set as long as they do not hinder the movement of anions and / or lithium ions. In addition, as materials for the negative electrode current collector 15b and the positive electrode current collector 14b, various materials generally proposed for organic electrolyte batteries can be used. For example, examples of the material of the negative electrode current collector 15b include stainless steel, copper, and nickel, and examples of the material of the positive electrode current collector 14b include aluminum and stainless steel.

[D] Separator Examples of the separator 13 include a porous body that has durability against an electrolytic solution, a positive electrode active material, a negative electrode active material, and the like and has continuous air holes and has no electronic conductivity. Usually, paper (cellulose), glass fiber, polyethylene, polypropylene, or other cloth, nonwoven fabric, or porous material is used. The thickness of the separator 13 is preferably thin in order to reduce the internal resistance of the battery, but can be appropriately set in consideration of the amount of electrolyte retained, the flowability, the strength, and the like.

[E] Electrolytic Solution As the electrolytic solution, it is preferable to use an aprotic organic solvent containing a lithium salt from the viewpoint of not causing electrolysis even at a high voltage and from the viewpoint that lithium ions can exist stably. Examples of the aprotic organic solvent include solvents in which ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, acetonitrile, dimethoxyethane, tetrahydrofuran, dioxolane, methylene chloride, sulfolane and the like are used alone or in combination. Examples of the lithium salt include LiClO ₄ , LiAsF ₆ , LiBF ₄ , LiPF ₆ , and LiN (C ₂ F ₅ SO ₂ ) ₂ .

[F] Laminate Film As the laminate film 11, various materials generally used for batteries can be used. In general, a three-layer laminate film having a nylon film on the outside, an aluminum foil in the center, and an adhesive layer such as modified polypropylene on the inside is used.

  Hereinafter, based on an Example, this invention is demonstrated in detail.

Example 1
(Manufacture of negative electrode)
The resin was cured by holding furfuryl alcohol, which is a raw material of furan resin charcoal, at 60 ° C. for 24 hours to obtain a black resin. The obtained black resin was placed in a static electric furnace, heated to 1200 ° C. in 3 hours in a nitrogen atmosphere, and held at that temperature for 2 hours. The sample taken out after cooling by cooling was pulverized with a ball mill to obtain a sample of D50% = 5.0 μm non-graphitizable carbon powder (hydrogen atom / carbon atom = 0.008).

  Next, a negative electrode slurry was obtained by sufficiently mixing 100 parts by weight of the sample and a solution in which 10 parts by weight of polyvinylidene fluoride powder was dissolved in 80 parts by weight of N-methylpyrrolidone. The negative electrode slurry was evenly coated on both surfaces of a negative electrode current collector made of a copper expanded metal having a thickness of 32 μm (porosity 50%) with a die coater, dried and pressed to obtain a negative electrode having a thickness of 70 μm.

(Manufacture of positive electrode)
By mixing thoroughly with a composition comprising 85 parts by weight of commercially available activated carbon powder having a specific surface area of 2000 m ² / g, 5 parts by weight of acetylene black powder, 6 parts by weight of acrylic resin binder, 4 parts by weight of carboxymethylcellulose and 200 parts by weight of water. A positive electrode slurry was obtained.

A positive electrode current collector in which a conductive layer was formed was obtained by coating a non-aqueous carbon-based conductive paint on both sides of an aluminum expanded metal having a thickness of 35 μm (porosity 50%) by a spray method and drying. . The total thickness (the total of the current collector thickness and the conductive layer thickness) was 52 μm, and the through hole was almost blocked by the conductive paint. The slurry was evenly coated on both surfaces of the positive electrode current collector with a roll coater, dried and pressed to obtain a positive electrode having a thickness of 129 μm. The thickness of the positive electrode layer of the positive electrode was 77 μm, and the basis weight of the positive electrode active material was 3.5 mg / cm ² .

(Production of three-pole laminated unit)
The negative electrode was cut into 11 sheets at 6.0 × 7.5 cm ² (excluding the terminal welded portion), and the positive electrode was cut into 10 sheets at 5.8 × 7.3 cm ² (excluding the terminal welded portion). The separators were arranged so that the terminal welded portions of the positive electrode current collector and the negative electrode current collector were opposite to each other through a 35 μm thick cellulose / rayon mixed nonwoven fabric as a separator, and the positive electrodes and the negative electrodes were alternately laminated. In addition, it laminated | stacked so that the outermost part of an electrode might become a negative electrode. The uppermost part and the lowermost part have separators arranged and taped on the four sides. The terminal welded part of the positive electrode current collector (10 sheets) and the terminal welded part of the negative electrode current collector (11 sheets) are each 50 mm wide and long. An electrode laminate unit was obtained by ultrasonic welding to an aluminum positive electrode terminal and a copper negative electrode terminal having a thickness of 50 mm and a thickness of 0.2 mm.

  As a lithium electrode, a metal lithium foil bonded to an 80 μm-thick stainless steel mesh is used, and one lithium electrode is placed on the upper part of the electrode stacking unit so as to be completely opposed to the outermost negative electrode. Got a unit. The terminal welded portion of the lithium electrode current collector was resistance welded to the negative electrode terminal welded portion.

(Cell preparation and electrolyte impregnation)
The above-mentioned three-electrode laminate inside a laminate film having a 3.5 mm unit housing part deeply drawn in accordance with the shape of the electrode lamination unit and a storage part deeply drawn separately from the unit housing part for storing the electrolyte solution The unit was installed, and the lower side and side sides of the laminate film were heat-sealed. Here, the storage part for storing the electrolytic solution was heat-sealed on three sides so as to be located on the opposite side of the remaining one side which is the upper side part of the laminate film which is not heat-sealed.

Subsequently, a funnel was inserted into the other side where heat fusion was not performed, and 15 g of a solution in which LiPF ₆ was dissolved with propoid so as to have a concentration of 1 mol / L with respect to propylene carbonate as an electrolytic solution was poured. Liquid. The electrolyte flowed smoothly into the lower reservoir. Thereafter, the remaining side was fused under reduced pressure to assemble 4 cell-type cells. In addition, the metallic lithium arrange | positioned in a cell is equivalent to 500 mAh / g per negative electrode active material weight.

  After assembling the cell, the reservoir was turned up and the electrolyte in the reservoir was completely impregnated inside the cell, and then heat-sealed between the reservoir and the unit accommodating portion to remove the reservoir.

(Initial evaluation of the cell)
When one cell was decomposed after being left for 20 days after impregnation with the electrolyte, all of the lithium metal was completely removed, so that 500 mAh / g of lithium ions were pre-doped per unit weight of the negative electrode active material. It was judged.

(Characteristic evaluation of cells)
The battery was charged at a constant current of 1000 mA until the cell voltage reached 3.8 V, and then a constant current-constant voltage charge in which a constant voltage of 3.8 V was applied was performed for 30 minutes. Next, the battery was discharged at a constant current of 500 mA until the cell voltage was 2.2V. This cycle of 3.8V-2.2V was repeated, and the cell capacity and energy density in the 10th discharge were evaluated. Subsequently, after being left in a constant temperature bath at 60 ° C., a voltage of 3.8 V was continuously applied, and after 1000 hours, the temperature was returned to room temperature to evaluate the cell capacity. The results are shown in Table 1 together with the capacity retention after the 3.8 V application test at 60 ° C. However, the data is an average of 3 cells.

(Comparative Example 1)
As in Example 1, except that a laminate film that does not have a reservoir for storing the electrolyte is used, a three-pole laminate unit is installed inside the laminate film that is deeply drawn by 3.5 mm, and the three sides of the laminate film are heated. Fused.

(Impregnation with electrolyte and cell preparation)
A funnel is inserted into the other side where the laminated film is not heat-sealed, and a solution of LiPF ₆ dissolved in a dropper so as to have a concentration of 1 mol / L with respect to propylene carbonate as an electrolytic solution. While pouring, the vacuum impregnation was repeated to impregnate a total amount of 15 g. Thereafter, the remaining side was fused under reduced pressure to assemble 4 film type cells. In addition, the metallic lithium arrange | positioned in a cell is equivalent to 500 mAh / g per negative electrode active material weight.

(Initial evaluation of the cell)
When one cell was disassembled after being left for 20 days after assembling the cell, all of the lithium metal was completely removed, so it was judged that 500 mAh / g lithium ion was pre-doped per unit weight of the negative electrode active material. .

(Characteristic evaluation of cells)
The battery was charged at a constant current of 1000 mA until the cell voltage reached 3.8 V, and then a constant current-constant voltage charge in which a constant voltage of 3.8 V was applied was performed for 30 minutes. Next, the battery was discharged at a constant current of 500 mA until the cell voltage was 2.2V. This cycle of 3.8V-2.2V was repeated, and the cell capacity and energy density in the 10th discharge were evaluated. Subsequently, after being left in a constant temperature bath at 60 ° C., a voltage of 3.8 V was continuously applied, and after 1000 hours, the temperature was returned to room temperature to evaluate the cell capacity. The results are shown in Table 2 together with the capacity retention after the 3.8 V application test at 60 ° C. However, the data is an average of 3 cells.

  Since Example 1 and Comparative Example 1 use the same electrode laminate unit, the initial discharge capacity is the same, but the capacity retention after 1000 hours of 3.8 V continuous application test at 60 ° C. The result of 1 was superior. This is thought to be because Example 1 used a laminate film having a reservoir for storing the electrolyte solution as a method for injecting the electrolyte solution, and smoothly completed the injection. According to this method, the assembly of the cell is simplified, and the time during which the three-pole laminated unit and the electrolyte are exposed to the atmosphere is extremely short. Therefore, it is presumed that the amount of moisture adsorption is reduced and stabilized.

(Comparative Example 2)
The three sides of the exterior laminate film were heat-sealed in the same manner as in Example 1 except that one side of the upper side that was not heat-sealed was the storage portion side that stores the electrolyte.

(Electrolyte impregnation step and production of cell 3)
A funnel is inserted into the other side where the laminated film is not heat-sealed, and a solution in which LiPF ₆ is dissolved with propoid so as to have a concentration of 1 mol / L with respect to propylene carbonate as an electrolytic solution is electrolyzed. 15 g of liquid was injected into the reservoir for storing the liquid. When the pressure was reduced in order to fuse the remaining side immediately after the injection, the electrolyte solution in the reservoir portion splattered due to defoaming and could not be fused. For this reason, after all the electrolyte solution of the storage part flowed down to the unit storage part in the laminate film, the remaining one side was again fused under reduced pressure, and 4 film type cells were assembled. In addition, the metallic lithium arrange | positioned in a cell is equivalent to 500 mAh / g per negative electrode active material weight.

  After the cell assembly, the reservoir was removed by heat fusion between the reservoir and the unit housing.

(Initial evaluation of the cell)
When one cell was decomposed after being left for 20 days after impregnation with the electrolyte, all of the lithium metal was completely removed, so that 500 mAh / g of lithium ions were pre-doped per unit weight of the negative electrode active material. It was judged.

(Characteristic evaluation of cells)
The battery was charged at a constant current of 1000 mA until the cell voltage reached 3.8 V, and then a constant current-constant voltage charge in which a constant voltage of 3.8 V was applied was performed for 30 minutes. Next, the battery was discharged at a constant current of 500 mA until the cell voltage was 2.2V. This cycle of 3.8V-2.2V was repeated, and the cell capacity and energy density in the 10th discharge were evaluated. Subsequently, after being left in a constant temperature bath at 60 ° C., a voltage of 3.8 V was continuously applied, and after 1000 hours, the temperature was returned to room temperature to evaluate the cell capacity. The results are shown in Table 3 together with the capacity retention after the 3.8 V application test at 60 ° C. However, the data is an average of 3 cells.

  As in Comparative Example 1, since it takes time to assemble the cell, the amount of moisture mixed in increased, and the durability is considered to be lower than that of Example 1. For this reason, the effect of the present invention cannot be obtained by injecting the electrolyte from the reservoir for storing the electrolyte.

  The power storage device to which the present invention can be applied is not limited to the above-described lithium ion capacitor, but may be other types of batteries and capacitors such as a lithium ion battery and an electric double layer capacitor.

  The power storage device of the present invention is extremely effective as a drive storage power source or auxiliary storage power source for an electric vehicle, a hybrid vehicle, or the like. Moreover, for example, it can be suitably used as a storage power source for driving electric bicycles, wheelchairs, etc., a storage power source used for solar power generators, wind power generators, etc., and a storage power source used for portable devices, household appliances, etc. Is possible.

It is a perspective view which shows the electrical storage device which is one embodiment of this invention. It is a disassembled perspective view which shows the internal structure of an electrical storage device. It is sectional drawing which shows the internal structure of an electrical storage device. It is sectional drawing which expands and shows the internal structure of an electrical storage device partially. It is explanatory drawing which shows the manufacturing method of an electrical storage device. It is explanatory drawing which shows the manufacturing method of an electrical storage device. It is explanatory drawing which shows the manufacturing method of an electrical storage device. (A) And (B) is explanatory drawing which shows the procedure at the time of isolate | separating a storage part from an electrical storage device.

Explanation of symbols

10 Power storage device 11 Laminate film (exterior film)
11a Unit accommodating portion 11b Reserving portion 11c Upper side portion 11d Lower side portion 11e Side side portion 13 Separator 14 Positive electrode 14a Through hole 14b Positive electrode current collector 15 Negative electrode 15a Through hole 15b Negative electrode current collector 16 Lithium electrode (lithium ion supply source)
17 Tripolar laminated unit (electrode unit)

Claims (9)

A method for producing an electricity storage device having an electrode unit including a positive electrode and a negative electrode, and an exterior film that is accommodated with the electrode unit interposed therebetween,
A unit housing part in which the electrode unit is housed in the exterior film, a lower side part located below the unit housing part when injecting the electrolyte, and an upper side part located above the unit housing part when injecting the electrolyte And forming a side part located on the side of the unit housing part at the time of electrolyte injection, and a storage part located between the unit housing part and the lower side part,
Sealing the lower side part and the side part after injecting an electrolyte from the upper side part and sealing the upper side part in a state where the electrolytic solution is stored in the storage part below the electrode unit. A method for manufacturing an electricity storage device. In the manufacturing method of the electrical storage device according to claim 1,
A method for manufacturing an electricity storage device, comprising injecting an electrolytic solution from the upper side under a first pressure atmosphere and sealing the upper side under a second pressure atmosphere lower in pressure than the first pressure atmosphere. An electricity storage device having an electrode unit including a positive electrode and a negative electrode, and an exterior film that is accommodated with the electrode unit interposed therebetween,
The exterior film includes a unit accommodating portion in which the electrode unit is accommodated, a lower side portion located below the unit accommodating portion when the electrolyte is injected, and an upper side portion located above the unit accommodating portion when the electrolyte is injected. And forming a side part located on the side of the unit housing part at the time of electrolyte injection, and a storage part located between the unit housing part and the lower side part,
After the lower side and side sides are sealed, the electrolyte is injected from the upper side, and the upper side is sealed under the condition that the electrolyte is stored in the storage part below the electrode unit. An electricity storage device characterized by the above. The electricity storage device according to claim 3,
An electric storage device, wherein an electrolyte is injected from the upper side under a first pressure atmosphere, and the upper side is sealed under a second pressure atmosphere lower in pressure than the first pressure atmosphere. The electricity storage device according to claim 3 or 4,
An electrical storage device, wherein after the electrode unit is impregnated with the electrolytic solution in the storage section, the storage section functions as a gas storage section at the time of abnormality. In the electrical storage device of any one of Claims 3-5,
The capacity of the storage unit is set to be lower than the injection amount of the electrolytic solution. In the electrical storage device of any one of Claims 3-6,
The electrical storage device, wherein the electrolytic solution is an aprotic organic solvent. In the electrical storage device of any one of Claims 3-7,
A power storage device, wherein a positive electrode potential when the positive electrode and the negative electrode are short-circuited is 2 V (vs. Li / Li ⁺ ) or less. In the electrical storage device of any one of Claims 3-8,
A lithium ion source that is short-circuited to at least one of the negative electrode and the positive electrode;
Forming a through-hole through which lithium ions pass through the current collector of the positive electrode and the negative electrode;
One of the negative electrode and the positive electrode is doped with lithium ions from the lithium ion supply source.

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