WO2007032365A1 - Battery-use electrode - Google Patents

Battery-use electrode Download PDF

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Publication number
WO2007032365A1
WO2007032365A1 PCT/JP2006/318114 JP2006318114W WO2007032365A1 WO 2007032365 A1 WO2007032365 A1 WO 2007032365A1 JP 2006318114 W JP2006318114 W JP 2006318114W WO 2007032365 A1 WO2007032365 A1 WO 2007032365A1
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WO
WIPO (PCT)
Prior art keywords
active material
battery
electrode active
material layer
positive electrode
Prior art date
Application number
PCT/JP2006/318114
Other languages
French (fr)
Japanese (ja)
Inventor
Kazuki Miyatake
Tamaki Miura
Tomaru Ogawa
Mikio Kawai
Original Assignee
Nissan Motor Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nissan Motor Co., Ltd. filed Critical Nissan Motor Co., Ltd.
Publication of WO2007032365A1 publication Critical patent/WO2007032365A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a battery electrode.
  • the present invention relates to an improvement for improving the output characteristics of a battery.
  • a lithium ion secondary battery As a secondary battery for driving a motor, a lithium ion secondary battery having the highest theoretical energy is attracting attention among all batteries, and development is proceeding rapidly at present.
  • a lithium ion secondary battery uses a binder to coat a positive electrode active material or the like on both sides of a positive electrode current collector, and a binder to coat the negative electrode active material or the like on both sides of the negative electrode current collector.
  • the negative electrode is connected via an electrolyte layer and is housed in a battery case.
  • Lithium ion secondary batteries used as power sources for driving motors such as automobiles as described above have extremely high output characteristics compared to consumer lithium ion secondary batteries used in mobile phones, laptop computers, etc. At present, research and development is underway to meet the strong demands.
  • JP 2003-68299 A discloses lithium containing a Li-Mn-Ni composite oxide.
  • a positive electrode active material for a secondary battery wherein the average diameter of primary particles of Li Mn—Ni composite oxide is 2.0 m or less and the BET specific surface area is 0.4 m 2 Zg or more.
  • a featured positive electrode active material for lithium ion secondary batteries is disclosed.
  • a lithium ion secondary battery having excellent discharge capacity characteristics and cycle durability can be provided.
  • the surface area of the positive electrode active material that can be contacted with the electrolyte increases, and as a result, the charge / discharge reaction can proceed sufficiently.
  • the present inventors diligently searched for the essence of increasing the internal resistance under high output conditions. As a result, it has been found that the increase in internal resistance such as force is due to insufficient formation of a conductive network as the particle size of the active material decreases. Based on this knowledge, the present inventors examined securing the conductive network by bringing the particles of the active material into contact with each other by reducing the porosity of the active material layer of the electrode.
  • the present inventors have found that the above problems can be solved by controlling the particle diameter of the active material and the porosity of the active material layer to predetermined values. This led to the completion.
  • the battery electrode according to the first aspect of the present invention is for a battery having a current collector and a first positive electrode active material layer containing a positive electrode active material formed on the current collector.
  • An electrode is characterized in that the positive electrode active material has an average particle diameter of 5 m or less, and the porosity of the first positive electrode active material layer is 30% or more.
  • the battery electrode according to the second aspect of the present invention is a current collector. And a first negative electrode active material layer containing a negative electrode active material formed on the current collector, the average particle diameter of the negative electrode active material being 10 m or less, The negative electrode active material layer 1 has a porosity of 50% or more.
  • the method for manufacturing a battery electrode according to the present invention includes an active material slurry adjustment step of adjusting an active material slurry containing an active material by adding an active material to a solvent, and a surface of a current collector. It has a coating film forming process for forming a coating film by applying and drying an active material slurry, and a pressing process for pressing the laminate produced through the coating film forming process in the laminating direction. The combination process with the pressing process is repeated twice or more.
  • FIG. 2 is a cross-sectional view showing another embodiment (second embodiment) of the battery electrode of the present invention.
  • FIG. 3 is a cross-sectional view showing a preferred embodiment of the bipolar battery of the third embodiment.
  • Fig. 5 is a schematic view of the automobile of the fifth embodiment on which the assembled battery of the fourth embodiment is mounted.
  • FIG. 6 is a cross-sectional view showing an outline of a lithium ion secondary battery that is not bipolar.
  • FIG. 7 is a graph showing the relationship between the porosity of the positive electrode active material layer and the relative output in the battery electrode of the example of the present invention.
  • FIG. 8 is a graph showing the relationship between the porosity of the positive electrode active material layer and the relative output in the battery electrodes of Examples and Comparative Examples of the present invention.
  • FIG. 1 is a cross-sectional view showing one embodiment of a battery electrode of the present invention.
  • the battery electrode 1 in the form shown in FIG. 1 is a bipolar electrode in which a positive electrode active material layer 13 is formed on one surface of a current collector 11 and a negative electrode active material layer 15 is formed on the other surface.
  • the average particle diameter of the positive electrode active material contained in the positive electrode active material layer 13 is 5 ⁇ m or less.
  • the average particle size is preferably 3 ⁇ m or less, more preferably 1 m or less.
  • the lower limit value of the average particle diameter of the positive electrode active material is not particularly limited, but from the viewpoint of sufficiently forming a conductive network in the electrode, the positive electrode active material.
  • the average particle diameter of is preferably 0.01 ⁇ m or more, more preferably 0.1 ⁇ m or more.
  • the porosity of the positive electrode active material layer 13 is 30% or more. The porosity is preferably 33% or more, more preferably 35% or more.
  • the upper limit of the porosity of the positive electrode active material layer 13 is not particularly limited from the viewpoint of obtaining the effect of the present invention. From the viewpoint of improving the battery capacity, the porosity of the positive electrode active material layer 13 is , Preferably 50% or less, more preferably 45% or less.
  • the average particle size of the negative electrode active material contained in the negative electrode active material layer 15 is 10 ⁇ m or less.
  • the average particle size is preferably 5 ⁇ m or less, more preferably 1 ⁇ m or less.
  • the lower limit of the average particle diameter of the negative electrode active material is not particularly limited, but from the viewpoint of sufficiently forming a conductive network in the electrode, the negative electrode active material
  • the average particle size of is preferably 0.01 ⁇ m or more, more preferably 0.1 ⁇ m or more.
  • the porosity of the negative electrode active material layer 15 is 50% or more.
  • the porosity is preferably 52% or more, more preferably 55% or more.
  • the upper limit of the porosity of the negative electrode active material layer 15 is not particularly limited as to the viewpoint power to obtain the effects of the present invention, but the viewpoint power to improve battery capacity is not limited to the porosity of the negative electrode active material layer 15. Is preferably 80% or less, more preferably 70% or less.
  • the value measured by the particle size distribution measurement method is adopted as the value of the particle diameter of the active material.
  • the porosity of the active material layer a value calculated according to the following formula 1 shall be adopted.
  • the electrode density [ g / mL] TM ⁇ slurry_ ⁇ 3 ⁇ 4
  • the theoretical electrode density [g / mL] ⁇ (electrode constituent material true density X active material layer composition ratio).
  • the nanopolar electrode of the form shown in FIG. 1 can be employed in, for example, a bipolar lithium ion secondary battery (hereinafter also simply referred to as “bipolar battery”). Of course, it may be adopted for other batteries.
  • bipolar battery a bipolar lithium ion secondary battery
  • the average particle diameter of the active material and the voids of the active material layer are the above-described values in both the positive electrode and the negative electrode, but the technical scope of the present invention is powerful.
  • the present invention is not limited only to the form, and a form in which only one of the positive electrode and the negative electrode satisfies the predetermined value described above can also be included.
  • the configuration of the battery electrode of the present invention will be described below by taking as an example a case where it is employed in a lithium ion secondary battery.
  • the battery electrode of this embodiment is characterized in that the average particle of the active material and the porosity of the active material layer are predetermined values for each of the positive electrode and the negative electrode.
  • the selection of the current collector There is no particular limitation on the selection of the current collector, the type of active material, the binder, the supporting salt (lithium salt), the electrolyte, and other compounds added as necessary. Depending on the intended use, it may be selected by appropriately referring to known knowledge.
  • the members constituting the battery electrode of the present invention will be described in detail.
  • the current collector 11 is made of a conductive material such as aluminum foil, nickel foil, copper foil, or stainless steel (SUS) foil.
  • the typical thickness of the current collector is 1-30 m. However, a current collector having a thickness outside this range may be used.
  • the size of the current collector is determined according to the intended use of the battery. If a large electrode used for a large battery is produced, a current collector with a large area is used. If a small electrode is produced, a current collector with a small area is used.
  • active material layers (13, 15) are formed on the current collector 11.
  • the active material layers (11, 15) are layers containing an active material that plays a central role in charge / discharge reactions.
  • the average particle diameter and the porosity of the active material satisfy the above-described predetermined values for either one or both of the positive electrode active material layer 13 and the negative electrode active material layer 15.
  • the active material layers (13, 15) include an active material.
  • the active material layer contains a positive electrode active material.
  • the active material layer contains a negative electrode active material.
  • Examples of the positive electrode active material include lithium transition metal oxides, lithium transition metal phosphate compounds, and lithium transition metal sulfate compounds. In some cases,
  • Two or more positive electrode active materials may be used in combination.
  • Examples of the negative electrode active material include carbon materials, lithium transition metal compounds, metal materials, and lithium metal alloy materials. In some cases, two or more negative electrode active materials may be used in combination.
  • the active material layers (13, 15) may contain other materials if necessary.
  • the active material layers (13, 15) may contain other materials if necessary. For example
  • Conductive aids such as, binders, supporting salts (lithium salts), ion conductive polymers, and the like.
  • a polymerization initiator for polymerizing the polymer may be included! / ⁇ .
  • the conductive auxiliary agent is an additive blended to improve the conductivity of the active material layer.
  • conductive assistants include carbon black such as acetylene black, carbon powder such as graphite, and various carbon fibers such as vapor grown carbon fiber (VGCF (registered trademark)). I can get lost.
  • the average particle diameter of the active material in the positive electrode active material layer 13 of the battery electrode and the porosity of the active material layer 13 are the predetermined values described above.
  • the positive electrode active material layer 13 desirably contains 5% by mass or more, more preferably 10% by mass or more of the conductive auxiliary with respect to the total mass of the positive electrode active material layer 13.
  • the negative electrode active material layer 15 preferably contains 1% by mass or more, more preferably 5% by mass or more of a conductive additive with respect to the total mass of the negative electrode active material layer 15.
  • Examples of the noinder include polyvinylidene fluoride (PVdF), a synthetic rubber binder, and the like.
  • the supporting salt includes Li (C F SO) N, LiPF, LiBF, LiAsF, LiCF
  • Examples of the ion conductive polymer include a polyethylene oxide (PEO) -based polymer and a polypropylene oxide (PPO) -based polymer.
  • the polymer may be the same as or different from the ion conductive polymer used in the electrolyte layer of the battery in which the electrode of the present invention is employed. preferable.
  • the polymerization initiator is blended so as to act on the crosslinkable group of the ion conductive polymer to advance the crosslinking reaction. Depending on the external factors to act as an initiator, it is classified into photopolymerization initiator, thermal polymerization initiator, etc.
  • the polymerization initiator include azobisisoptyl-tolyl (AIBN), which is a thermal polymerization initiator, and benzyl dimethyl ketal (BDK), which is a photopolymerization initiator.
  • the mixing ratio of the components contained in the active material layers (13, 15) is not particularly limited.
  • the blending ratio can be adjusted by appropriately referring to known knowledge about lithium ion secondary batteries.
  • the thickness of the active material layer (13, 15) is not particularly limited can be appropriately referred to.
  • the thickness of the active material layer (13, 15) is preferably about 10 to about L00 m, and more preferably about 20 to 50 m. Life If the material layers (13, 15) are about 10 / zm or more, the battery capacity can be sufficiently secured. On the other hand, if the active material layer (13, 15) is about 100 ⁇ m or less, the problem of increased internal resistance due to diffusion of lithium ions to the electrode deep part (current collector side) is suppressed. Can be.
  • the active material layers (13, 15) of the battery electrode of the present invention may comprise two or more layers.
  • the electrode of the present invention will be described with reference to the drawings, taking as an example the case where each of the positive electrode active material layer 13 and the negative electrode active material layer 15 is composed of two layers.
  • FIG. 2 is a cross-sectional view showing another embodiment of the battery electrode of the present invention.
  • the positive electrode active material layer 13 is formed on one surface of the current collector 11 and the negative electrode active material is formed on the other surface, similarly to the electrode having the form shown in FIG. This is a bipolar electrode in which the layer 15 is formed.
  • the battery electrode 1 having the form shown in FIG. 2 includes the current collector 11, the average particle diameter of the active material and the porosity of the active material layer described above in each of the positive electrode active material layer 13 and the negative electrode active material layer 15.
  • the second active material layer (13b, 1a) having a lower porosity than the first active material layer (13a, 15a) between the first positive electrode active material layer (13a, 15a) that satisfies the above requirements 5b) is characterized by intervening.
  • the second active material layer (13b, 15b) is located on the current collector 11 side, and the first active material layer Material layers (13a, 15a) are located on the electrolyte side of the battery. According to such a configuration, by disposing an active material layer with a higher porosity on the electrolyte side, it is possible to diffuse lithium ions deep into the entire electrode active material layer (current collector 11 side). Become.
  • the internal resistance of the battery (mainly due to the diffusion resistance of lithium ions) can be reduced.
  • an active material layer having a smaller porosity on the current collector 11 side it is possible to ensure the filling rate of the active material in the entire electrode active material layer. As a result, the capacity characteristics and output characteristics of the battery can be sufficiently secured.
  • the specific form of the first active material layer (13a, 15a) is as described above, and thus detailed description thereof is omitted here.
  • the second active material layer (13b, 15b) is connected to the first active material layer (second positive electrode active material layer 13b) corresponding to each porosity.
  • the first positive electrode active material layer 13a; the second negative electrode active material layer 15b has a lower porosity than the first negative electrode active material layer 13a)! /
  • the form is not particularly limited.
  • FIG. 2 illustrates a form in which each of the active material layers (13, 15) is composed of two layers.
  • the technical scope of the present invention is not limited to such a form, and either It is also possible to include a form in which the active material layer is composed of one layer or a form in which three or more layers of force are present.
  • the electrode of the present invention for example, prepares an active material slurry by adding an active material to a solvent (active material slurry preparation step), applies the active material slurry to the surface of the current collector, It can be produced by forming a coating film by drying (coating film forming process) and pressing the laminate produced through the coating film forming process in the laminating direction (pressing process).
  • active material slurry preparation step When an ion conductive polymer is added to the active material slurry and a polymerization initiator is further added for the purpose of cross-linking the ion conductive polymer, at the same time as drying in the coating film forming process or before the drying.
  • a polymerization treatment may be performed later (polymerization step).
  • the desired active material and other components are mixed in a solvent as necessary.
  • an active material slurry is prepared.
  • the specific form of each component blended in the active material slurry is as described in the column of the configuration of the electrode of the present invention, and a detailed description is omitted here.
  • the type of solvent and the mixing means are not particularly limited, and conventionally known knowledge about electrode production can be appropriately referred to.
  • the solvent N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, methylformamide and the like can be used.
  • NMP N-methyl-2-pyrrolidone
  • PVdF polyvinylidene fluoride
  • the porosity of the active material layer of the produced electrode is adjusted by adjusting the mixing ratio of the solid content and the solvent in the active material slurry prepared in the active material slurry preparation step. It is also possible to control. Specifically, when it is desired to reduce the porosity of the formed active material layer, the amount of solid content in the active material slurry should be increased. On the other hand, when it is desired to increase the porosity of the active material layer to be formed, the blending amount of the solid content in the active material slurry is preferably decreased. However, the porosity of the active material layer may be controlled in a coating process and a pressing process described later.
  • a current collector is prepared, and the active material slurry prepared above is applied to the surface of the current collector and dried. As a result, a coating film made of the active material slurry is formed on the surface of the current collector. This coating film becomes an active material layer through a pressing step described later.
  • the application means for applying the active material slurry is not particularly limited.
  • a commonly used means such as a self-propelled coater can be adopted.
  • an ink jet method as a coating unit because finer adjustment is possible and the porosity of the active material layer can be more easily controlled.
  • the coating film is formed according to a desired arrangement of the current collector and the active material layer in the manufactured electrode. For example, in the case of a manufactured electrode force S bipolar electrode, a coating film containing a positive electrode active material is formed on one surface of the current collector, and a coating film containing a negative electrode active material is formed on the other surface. . On the other hand, when manufacturing a non-polar electrode, a coating film containing either the positive electrode active material or the negative electrode active material is formed on both surfaces of one current collector.
  • the coating film formed on the surface of the current collector is dried. Thereby, the solvent in the coating film is removed.
  • the drying means for drying the coating film is not particularly limited, and conventionally known knowledge about electrode production can be appropriately referred to. For example, heat treatment is exemplified.
  • the drying conditions (drying time, drying temperature, etc.) are suitable for the amount of active material slurry applied and the volatilization rate of the solvent in the slurry. Can be set appropriately.
  • the coating film contains a polymerization initiator
  • the ion conductive polymer in the coating film is cross-linked by a crosslinkable group by further performing a polymerization step.
  • the polymerization treatment in the polymerization step is not particularly limited, and conventionally known knowledge may be referred to as appropriate.
  • the coating film contains a thermal polymerization initiator (AIBN, etc.)
  • the coating film is heat treated.
  • the coating film contains a photopolymerization initiator (BDK, etc.)
  • light such as ultraviolet light is irradiated.
  • the heat treatment for thermal polymerization may be performed at the same time as the above drying step, or may be performed before or after the drying step.
  • the laminated body produced through the said coating-film formation process is pressed to the lamination direction. Thereby, the battery electrode of the present invention is completed.
  • the porosity of the active material layer can be controlled by adjusting the pressing conditions.
  • Specific means and press conditions for the press treatment are not particularly limited, and can be appropriately adjusted so that the porosity of the active material layer after the press treatment becomes a desired value.
  • Specific examples of the press process include a hot press machine and a calendar roll press machine.
  • pressing conditions temperature, pressure, etc.
  • conventionally known knowledge in which pressing conditions (temperature, pressure, etc.) are particularly limited, can be referred to as appropriate.
  • the present application provides a method of manufacturing a battery electrode of a preferred form shown in FIG. That is, the battery electrode manufacturing method according to the present invention includes an active material slurry preparation step of preparing an active material slurry containing an active material by adding the active material to a solvent, and the active material on the surface of the current collector.
  • a coating film forming process for forming a coating film by applying slurry and drying; a pressing process for pressing the laminate produced through the coating film forming process in the stacking direction; and the coating film forming process and the press It is characterized by repeating the combination process with the process twice or more.
  • the manufacturing method repeats the combination step of the coating film forming step and the pressing step twice or more for the purpose of controlling the porosity of each layer of the active material layer having two or more layers. It has the characteristics.
  • a coating film is formed on the surface of the current collector 11 (first coating film forming process) and pressed (first pressing process).
  • first coating film forming process a coating film is formed on the surface of the current collector 11 (first coating film forming process) and pressed (first pressing process).
  • first pressing process As a result, the second shown in FIG. Active material layers (13b, 15b) are formed.
  • a coating film is formed again on the surface of the second active material layer (second coating film forming process) and pressed (second pressing process).
  • the first active material layers (13a, 15a) shown in FIG. 2 are formed, and the battery electrode having the configuration shown in FIG. 2 is completed.
  • the press pressure in the (n + 1) th press process (n ⁇ 1) is set smaller than the press pressure in the nth press process. If the manufacturing method described above is taken as an example, the pressing pressure in the second pressing step should be made smaller than the pressing pressure in the first pressing step. In this way, the porosity of the first active material layer (13a, 15a) formed by the second pressing process is changed to the second active material layer (13b, 15b) formed by the first pressing process. 2), the battery electrode having the configuration shown in FIG. 2 can be produced.
  • a lithium ion secondary battery is configured using the battery electrode of the first embodiment or the second embodiment. That is, a third aspect of the present invention is a lithium-ion secondary battery including at least one single battery layer laminated in this order, the positive electrode, the electrolyte layer, and the negative electrode force S, and at least one of the positive electrode or the negative electrode is It is a lithium ion battery which is an electrode for a battery of the present invention.
  • the electrode of the present invention can be applied to any of a positive electrode, a negative electrode, and a bipolar electrode.
  • a lithium ion secondary battery including the electrode of the present invention as at least one electrode belongs to the technical scope of the present invention. However, preferably, all of the electrodes constituting the lithium ion secondary battery are the electrodes of the present invention. By adopting such a configuration, the output characteristics of the lithium ion secondary battery can be effectively improved.
  • the battery of the present invention may be a bipolar lithium ion secondary battery (hereinafter also referred to as a bipolar battery).
  • FIG. 3 is a cross-sectional view showing a third lithium ion secondary battery of the present invention, which is a bipolar battery.
  • the bipolar battery shown in FIG. 3 will be described in detail as an example.
  • the technical blade of the present invention is not limited to only a powerful form.
  • the bipolar battery 10 of the present embodiment shown in FIG. 3 has a structure in which a substantially rectangular battery element 21 in which a charge / discharge reaction actually proceeds is sealed inside a laminate sheet 29 that is an exterior.
  • the battery element 21 of the bipolar battery 10 of the present embodiment includes a bipolar element in which a positive electrode active material layer 13 and a negative electrode active material difference 15 are formed on each surface of a current collector 11. It has a plurality of electrodes (bipolar electrodes of the form shown in FIG. 1). Each bipolar electrode is laminated via an electrolyte layer 17 to form a battery element 21.
  • each of the bipolar electrodes and the positive electrode active material layer 13 of one bipolar electrode and the negative electrode active material layer 15 of another bipolar electrode adjacent to the one bipolar electrode face each other through the electrolyte layer 17.
  • the electrolyte layer 1 is laminated.
  • the bipolar battery 10 has a configuration in which the unit cell layers 19 are laminated.
  • an insulating layer 31 for insulating the adjacent current collectors 11 is provided on the outer periphery of the unit cell layer 19.
  • the current collector (outermost layer current collector) (11a, ib) positioned on the outermost layer of the battery element 21 has a positive electrode active material layer 13 (positive electrode side outermost layer current collector 1) on only one side. la) or negative electrode active material layer 15 (negative electrode side outermost layer current collector 1 lb) is formed!
  • the positive electrode side outermost layer current collector 11a is extended to form a positive electrode tab 25, which is led out from a laminate sheet 29 which is an exterior.
  • 1 lb of the negative electrode side outermost layer current collector is extended to form a negative electrode tab 27, which is similarly led out from the laminate sheet 29.
  • electrolyte constituting the electrolyte layer 17 a liquid electrolyte or a polymer electrolyte can be used.
  • the liquid electrolyte has a form in which a lithium salt as a supporting salt is dissolved in an organic solvent as a plasticizer.
  • the organic solvent that can be used as the plasticizer include carbonates such as ethylene carbonate (EC) and propylene carbonate (PC).
  • EC ethylene carbonate
  • PC propylene carbonate
  • support As the supported salt (lithium salt), a compound that can be added to the active material layer of the electrode, such as LiBETI, can be similarly employed.
  • polymer electrolytes are classified into gel electrolytes containing an electrolytic solution and authentic polymer electrolytes containing no electrolytic solution.
  • the gel electrolyte has a configuration in which the above-described liquid electrolyte is injected into a matrix polymer having ion-conductive polymer power.
  • the ion conductive polymer used as the matrix polymer include polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof.
  • Electrolyte salts such as lithium salts can be well dissolved in such polyalkylene oxide polymers.
  • the electrolyte layer 17 is composed of a liquid electrolyte or a gel electrolyte
  • a separator may be used for the electrolyte layer 17.
  • a specific form of the separator for example, a microporous film that is also a polyolefin linker such as polyethylene or polypropylene can be cited.
  • the intrinsic polymer electrolyte has a structure in which a supporting salt (lithium salt) is dissolved in the above matrix polymer, and does not contain a plastic organic solvent. Therefore, when the electrolyte layer 17 is made of an intrinsic polymer electrolyte, the reliability of the battery can be improved without worrying about the leakage of liquid from the battery.
  • a supporting salt lithium salt
  • the matrix polymer of the gel electrolyte or the intrinsic polymer electrolyte can exhibit excellent mechanical strength by forming a crosslinked structure.
  • thermal polymerization, ultraviolet polymerization, radiation polymerization, electron beam polymerization, etc. are performed on a polymerizable polymer (for example, PEO or PPO) for forming a polyelectrolyte using an appropriate polymerization initiator.
  • the polymerization process may be performed.
  • an insulating layer 31 is usually provided around each unit cell layer 19. This insulating layer 31 is intended to prevent the adjacent current collectors 11 in the battery from contacting each other and short-circuiting due to slight unevenness at the end of the cell layer 19 in the battery element 21 or the like. Provided. The installation of a strong insulating layer 31 ensures long-term reliability and safety, and can provide a high-quality bipolar battery 10.
  • the insulating layer 31 has an insulating property, a sealing property against falling off of the fixed electrolyte, and water from the outside.
  • urethane resin, epoxy resin, polyethylene resin, polypropylene resin, polyimide resin can be used as long as they have a sealing property against moisture permeation (sealing property) and heat resistance under battery operating temperature. Fats, rubbers and the like can be used.
  • urethane resin and epoxy resin are preferred from the viewpoints of corrosion resistance, chemical resistance, ease of production (film forming property), and economical efficiency.
  • the material of the tabs is not particularly limited, and a known material conventionally used as a tab for a bipolar battery can be used.
  • a known material conventionally used as a tab for a bipolar battery can be used.
  • aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof are exemplified.
  • the positive electrode tab 25 and the negative electrode tab 27 may be made of the same material or different materials.
  • the outermost layer current collector (l la, ib) may be extended to form tabs (25, 27), or may be connected to a separately prepared outermost layer current collector. It's good.
  • the battery element 21 is preferably housed in an exterior such as a laminate sheet 29 in order to prevent external impact and environmental degradation during use.
  • the exterior is not particularly limited, and a conventionally known exterior can be used. From the viewpoint of efficiently transferring heat from a heat source of an automobile and quickly heating the inside of the battery to the battery operating temperature, a polymer metal composite laminate sheet having excellent heat conductivity can be preferably used.
  • an assembled battery is configured by connecting a plurality of the bipolar batteries of the above-described third embodiment in parallel and Z or in series.
  • FIG. 4 is a perspective view showing the assembled battery of this embodiment.
  • the assembled battery 40 is the bipolar battery described in the second embodiment. It is configured by connecting a plurality. Each bipolar battery 10 is connected by connecting the positive electrode tab 25 and the negative electrode tab 27 of each bipolar battery 10 using a bus bar. On one side surface of the assembled battery 40, electrode terminals (42, 43) are provided as electrodes of the assembled battery 40 as a whole.
  • connection method for connecting the plurality of bipolar batteries 10 constituting the assembled battery 40 is not particularly limited, and a conventionally known method can be appropriately employed. For example, a method using welding such as ultrasonic welding or spot welding, or a method of fixing using rivets or caulking can be employed. According to the powerful connection method, the long-term reliability of the assembled battery 40 can be improved.
  • the individual bipolar batteries 10 constituting the assembled battery 40 are excellent in output characteristics, and therefore an assembled battery excellent in output characteristics can be provided.
  • all of the bipolar batteries 10 constituting the assembled battery 40 may be connected in parallel, or all of the plurality of bipolar batteries 10 may be connected in series. You may combine the connection.
  • the bipolar battery 10 of the third embodiment or the assembled battery 40 of the fourth embodiment is mounted as a motor driving power source to constitute a vehicle.
  • Vehicles that use the bipolar battery 10 or the assembled battery 40 as a motor power source include, for example, gasoline! /, Fully electric vehicles, hybrid vehicles such as series hybrid vehicles and parallel hybrid vehicles, and fuel cell vehicles.
  • One example is an automobile that drives a vehicle by a motor.
  • FIG. 5 shows a schematic diagram of an automobile 50 in which the assembled battery 40 is mounted.
  • the assembled battery 40 mounted on the automobile 50 has the characteristics as described above. Therefore, the automobile 50 equipped with the assembled battery 40 has excellent output characteristics and can provide sufficient output even under high output conditions.
  • FIG. 6 shows a cross-sectional view showing an outline of a non-bipolar lithium ion secondary battery 60.
  • a cathode active material spinel-type lithium manganate (average particle size: 0. ⁇ ⁇ ⁇ ) (80 wt%)
  • acetylene black as a conductive aid (10 mass 0/0)
  • polyvinylidene fluoride A suitable amount of N-methyl-2-pyrrolidone (NMP), which is a slurry viscosity adjusting solvent, was added to the solid content of PVdF) (10% by mass) to prepare a positive electrode active material slurry.
  • NMP N-methyl-2-pyrrolidone
  • the positive electrode active material slurry prepared above was placed on an aluminum foil (thickness: 2 O / zm) as a positive electrode current collector, with a basis weight of 12.0 mgZcm 2 , a film thickness of 46 / zm was applied and dried to obtain a laminate.
  • the obtained laminate was pressed using a press so that the porosity of the positive electrode active material layer was 32%, and a tab was connected to the current collector to produce a test positive electrode.
  • Hard carbon as a negative electrode active material (average particle diameter: 10 m) (90 mass%), and by Sunda a is polyvinylidene Kapi - isopropylidene (PVdF) to (10 mass 0/0) solids consisting slurry viscosity An appropriate amount of N-methyl-2-pyrrolidone (NMP) as a adjusting solvent was added to prepare a negative electrode active material slurry.
  • NMP N-methyl-2-pyrrolidone
  • the negative electrode active material slurry prepared above was applied to a copper foil (thickness: 10 m) as a negative electrode current collector using a self-propelled die coater and a basis weight of 3 mg / cm 2 and a film thickness of 30 ⁇ m. And dried to obtain a laminate. Next, the obtained laminate was pressed using a press so that the porosity of the negative electrode active material layer was 55%, and a tab was connected to the current collector to prepare a test negative electrode. [0094] ⁇ Preparation of electrolyte solution>
  • Ethylene carbonate (EC) and jetyl carbonate (DEC) were mixed at a volume ratio of 1: 1 to obtain a plasticizer (organic solvent) for the electrolytic solution.
  • LiPF which is a lithium salt, was added to the plasticizer so as to have a concentration of 1M to prepare an electrolytic solution.
  • a polyethylene porous membrane (thickness: 25 m) as a separator for a lithium ion battery was sandwiched between the test positive electrode and the test negative electrode produced above.
  • the sandwiched body obtained in (1) was inserted into an aluminum laminate bag, which was a three-side sealed exterior material. Thereafter, the electrolyte prepared above was injected into the aluminate bag, and the pack was vacuum-sealed so that the tabs were also exposed to complete the laminated battery.
  • a laminated battery was produced in the same manner as in Example 1 except that the thickness of the positive electrode active material slurry was 49 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 35%. .
  • a laminated battery was produced in the same manner as in Example 1 except that the thickness of the positive electrode active material slurry was 52 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 39%. .
  • a laminated battery was produced in the same manner as in Example 1 except that the thickness of the positive electrode active material slurry was 58 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 45%. .
  • a laminated battery was produced in the same manner as in Example 1 except that the thickness of the positive electrode active material slurry was 61 ⁇ m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 48%. did.
  • Average particle of spinel type lithium manganate which is solid content of the positive electrode active material slurry A laminated battery was produced in the same manner as in Example 1 except that the diameter was 5 ⁇ m and the thickness of the positive electrode active material slurry was 47 ⁇ m.
  • a laminated battery was produced in the same manner as in Example 6 except that the thickness of the positive electrode active material slurry was 52 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 39%. .
  • a laminated battery was produced in the same manner as in Example 6 except that the thickness of the positive electrode active material slurry was 58 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 45%. .
  • the mass ratio of spinel type lithium manganate, acetylene black, and PVdF, which are solids in the positive electrode active material slurry, is 70:20:10, and the basis weight and film thickness of the positive electrode active material slurry are 13.7 mgZcm 2 and A laminated battery was produced in the same manner as in Example 1 except that the length was 56 m.
  • a laminated battery was produced in the same manner as in Example 9 except that the thickness of the positive electrode active material slurry was 59 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 35%. .
  • a laminated battery was produced in the same manner as in Example 9 except that the thickness of the positive electrode active material slurry was 63 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 39%. .
  • a laminated battery was produced in the same manner as in Example 9 except that the thickness of the positive electrode active material slurry was 74 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 45%. .
  • Example 13 A laminated battery was produced in the same manner as in Example 9 except that the thickness of the positive electrode active material slurry was 85 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 55%. .
  • a laminated battery was produced in the same manner as in Comparative Example 1 except that the thickness of the positive electrode active material slurry was 52 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 39%. .
  • a laminated battery was produced in the same manner as in Comparative Example 1 except that the thickness of the positive electrode active material slurry was 60 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 45%. .
  • a laminated battery was produced in the same manner as in Comparative Example 6 except that the thickness of the positive electrode active material slurry was 61 ⁇ m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 48%. did.
  • each laminate battery was initially charged at a constant current of 0.2 C, discharged at a constant current of 0.5 C, and then charged and discharged at 10 cycles at a constant current of 1 C. Went.
  • the average particle diameter of the positive electrode active material is as large as about 10 m, even if the porosity of the positive electrode active material layer increases, the diffusion resistance in the positive electrode active material layer is almost the same. Unaffected and relative output does not change.
  • the average particle diameter of the positive electrode active material is extremely small, the diffusion resistance in the positive electrode active material layer decreases corresponding to the increase in the porosity of the positive electrode active material layer, and the relative Output increases. Therefore, by combining the small particle size of the electrode active material and the increase in the porosity of the electrode active material, a battery capable of exhibiting excellent output characteristics even under a high output condition of 100 C can be provided. Is suggested.

Abstract

A battery-use electrode comprising a collector and a first positive active material formed on the collector and containing a positive active material, characterized in that an average particle size of the positive active material is up to 5μm, and the porosity of the first positive active material is at least 30%. Or, a battery-use electrode comprising a collector and a first negative active material formed on the collector and containing a positive active material, characterized in that an average particle size of the negative active material is up to 10μm, and the porosity of the first negative active material is at least 50%. Accordingly, a lithium ion secondary battery can provide a means of preventing an increase in the internal resistance of the battery at charging/discharging under a high output condition and delivering a sufficient current.

Description

明 細 書  Specification
電池用電極  Battery electrode
技術分野  Technical field
[0001] 本発明は、電池用電極に関する。特に本発明は、電池の出力特性を向上させるた めの改良に関する。  [0001] The present invention relates to a battery electrode. In particular, the present invention relates to an improvement for improving the output characteristics of a battery.
背景技術  Background art
[0002] 近年、大気汚染や地球温暖化に対処するため、二酸化炭素量の低減が切に望ま れて 、る。自動車業界では、電気自動車 (EV)やハイブリッド電気自動車 (HEV)の 導入による二酸ィ匕炭素排出量の低減に期待が集まっており、これらの実用化の鍵を 握るモータ駆動用二次電池の開発が盛んに行われて 、る。  In recent years, in order to cope with air pollution and global warming, reduction of the amount of carbon dioxide has been strongly desired. In the automobile industry, there are high expectations for reducing carbon dioxide emissions through the introduction of electric vehicles (EV) and hybrid electric vehicles (HEV). There is a lot of development.
[0003] モータ駆動用二次電池としては、全ての電池の中で最も高!、理論エネルギーを有 するリチウムイオン二次電池が注目を集めており、現在急速に開発が進められている 。リチウムイオン二次電池は、一般に、バインダを用いて正極活物質等を正極集電体 の両面に塗布した正極と、バインダを用 、て負極活物質等を負極集電体の両面に塗 布した負極とが、電解質層を介して接続され、電池ケースに収納される構成を有して いる。  [0003] As a secondary battery for driving a motor, a lithium ion secondary battery having the highest theoretical energy is attracting attention among all batteries, and development is proceeding rapidly at present. In general, a lithium ion secondary battery uses a binder to coat a positive electrode active material or the like on both sides of a positive electrode current collector, and a binder to coat the negative electrode active material or the like on both sides of the negative electrode current collector. The negative electrode is connected via an electrolyte layer and is housed in a battery case.
[0004] 上述したような自動車等のモータ駆動用電源として用いられるリチウムイオン二次 電池には、携帯電話やノートパソコン等に使用される民生用リチウムイオン二次電池 と比較して極めて高い出力特性を有することが求められており、力 うな要求に応え るべく鋭意研究開発が進められているのが現状である。  [0004] Lithium ion secondary batteries used as power sources for driving motors such as automobiles as described above have extremely high output characteristics compared to consumer lithium ion secondary batteries used in mobile phones, laptop computers, etc. At present, research and development is underway to meet the strong demands.
[0005] ここで、自動車への搭載を念頭にリチウムイオン二次電池の出力特性を向上させる ための技術として、特開 2003— 68299号公報に、 Li— Mn— Ni複合酸化物を含有 するリチウム二次電池用正極活物質であって、 Li Mn— Ni複合酸化物の 1次粒子 の平均直径が 2. 0 m以下であり、かつ、 BET比表面積が 0. 4m2Zg以上であるこ とを特徴とするリチウムイオン二次電池用正極活物質が開示されている。 [0005] Here, as a technique for improving the output characteristics of a lithium ion secondary battery in consideration of mounting in an automobile, JP 2003-68299 A discloses lithium containing a Li-Mn-Ni composite oxide. A positive electrode active material for a secondary battery, wherein the average diameter of primary particles of Li Mn—Ni composite oxide is 2.0 m or less and the BET specific surface area is 0.4 m 2 Zg or more. A featured positive electrode active material for lithium ion secondary batteries is disclosed.
[0006] 上記特許文献記載の技術によれば、放電容量特性およびサイクル耐久性に優れ るリチウムイオン二次電池が提供されうる。これは、正極活物質である Li Mn— Ni 複合酸化物の平均直径および比表面積が上記の値に制御されると、電解液と接触 可能な正極活物質の表面積が増大する結果、充放電反応が充分に進行しうるため であると考えられる。 [0006] According to the technology described in the above patent document, a lithium ion secondary battery having excellent discharge capacity characteristics and cycle durability can be provided. This is the positive electrode active material Li Mn— Ni When the average diameter and specific surface area of the composite oxide are controlled to the above values, the surface area of the positive electrode active material that can be contacted with the electrolyte increases, and as a result, the charge / discharge reaction can proceed sufficiently. .
[0007] このように、電極の活物質層に含まれる活物質の粒子径をより減少させることは、電 池の高出力化の観点からは好ましい。し力しながら、活物質の粒子径を減少させす ぎると、高出力条件下での充放電時における電池の内部抵抗が増大し、必要な電流 が充分に取り出せなくなってしまうと 、う問題があった。  [0007] As described above, it is preferable to reduce the particle diameter of the active material contained in the active material layer of the electrode from the viewpoint of increasing the output of the battery. However, if the particle size of the active material is reduced too much, the internal resistance of the battery during charge / discharge under high output conditions increases, and the necessary current cannot be sufficiently extracted. It was.
[0008] そこで本発明は、リチウムイオン二次電池において、高出力条件下での充放電時 における電池の内部抵抗の増大を抑制し、充分な電流を取り出しうる手段を提供す ることを目的とする。  [0008] Therefore, an object of the present invention is to provide a means for suppressing an increase in the internal resistance of a lithium ion secondary battery during charging / discharging under a high output condition and taking out a sufficient current. To do.
発明の開示  Disclosure of the invention
[0009] 本発明者らは、上記の課題に鑑み、高出力条件下での内部抵抗増大の原意を鋭 意探索した。その結果、力ような内部抵抗の増大は、活物質の粒子径の減少に伴つ て導電ネットワークが充分に形成されなくなることによりものであることを見出した。こ の知見に基づき、本発明者らは、電極の活物質層の空隙率を低下させることによつ て活物質の粒子どうしを接触させて、導電ネットワークを確保することを検討した。  [0009] In view of the above-mentioned problems, the present inventors diligently searched for the essence of increasing the internal resistance under high output conditions. As a result, it has been found that the increase in internal resistance such as force is due to insufficient formation of a conductive network as the particle size of the active material decreases. Based on this knowledge, the present inventors examined securing the conductive network by bringing the particles of the active material into contact with each other by reducing the porosity of the active material layer of the electrode.
[0010] 一方、活物質層の空隙率を低下させすぎると、導電ネットワークは充分に確保され るものの、やはり電池の内部抵抗が増大するという問題が生じた。本発明者らは、か ような空隙率の低下に伴う内部抵抗の原因をも鋭意探索した。その結果、かような内 部抵抗の増大は、電解質層からリチウムイオンの供給が充分になされないことに起因 することを見出した。  [0010] On the other hand, when the porosity of the active material layer is excessively reduced, the conductive network is sufficiently secured, but there is still a problem that the internal resistance of the battery increases. The present inventors have also eagerly searched for the cause of the internal resistance accompanying such a decrease in porosity. As a result, it was found that such an increase in internal resistance is caused by insufficient supply of lithium ions from the electrolyte layer.
[0011] これらの知見に基づき、本発明者らは、活物質の粒子径および活物質層の空隙率 を所定の値に制御することで、上記の課題が解決されうることを見出し、本発明を完 成させることに至った。  Based on these findings, the present inventors have found that the above problems can be solved by controlling the particle diameter of the active material and the porosity of the active material layer to predetermined values. This led to the completion.
[0012] すなわち、本発明の第 1の態様に係る電池用電極は、集電体と、集電体上に形成 された、正極活物質を含む第 1の正極活物質層とを有する電池用電極であって、正 極活物質の平均粒子径が 5 m以下であり、第 1の正極活物質層の空隙率が 30% 以上であることを特徴とする。また、本発明の第 2の態様に係る電池用電極は、集電 体と、集電体上に形成された、負極活物質を含む第 1の負極活物質層とを有する電 池用電極であって、負極活物質の平均粒子径が 10 m以下であり、第 1の負極活物 質層の空隙率が 50%以上であることを特徴とする。 That is, the battery electrode according to the first aspect of the present invention is for a battery having a current collector and a first positive electrode active material layer containing a positive electrode active material formed on the current collector. An electrode is characterized in that the positive electrode active material has an average particle diameter of 5 m or less, and the porosity of the first positive electrode active material layer is 30% or more. The battery electrode according to the second aspect of the present invention is a current collector. And a first negative electrode active material layer containing a negative electrode active material formed on the current collector, the average particle diameter of the negative electrode active material being 10 m or less, The negative electrode active material layer 1 has a porosity of 50% or more.
[0013] また、本発明に係る電池用電極の製造方法は、溶媒に活物質を添加することにより 、活物質を含む活物質スラリーを調整する活物質スラリー調整工程と、集電体の表面 に活物質スラリーを塗布し、乾燥させることにより塗膜を形成する塗膜形成工程と、塗 膜形成工程を経て作製された積層体を積層方向にプレスするプレス工程とを有し、 塗膜形成工程と、プレス工程との組み合わせ工程を 2回以上繰り返すことを特徴とす る。 [0013] Further, the method for manufacturing a battery electrode according to the present invention includes an active material slurry adjustment step of adjusting an active material slurry containing an active material by adding an active material to a solvent, and a surface of a current collector. It has a coating film forming process for forming a coating film by applying and drying an active material slurry, and a pressing process for pressing the laminate produced through the coating film forming process in the laminating direction. The combination process with the pressing process is repeated twice or more.
図面の簡単な説明  Brief Description of Drawings
[0014] [図 1]図 1は、本発明の電池用電極の一実施形態 (第 1実施形態)を示す断面図であ る。  FIG. 1 is a cross-sectional view showing one embodiment (first embodiment) of a battery electrode of the present invention.
[図 2]図 2は、本発明の電池用電極の他の実施形態 (第 2実施形態)を示す断面図で ある。  FIG. 2 is a cross-sectional view showing another embodiment (second embodiment) of the battery electrode of the present invention.
[図 3]図 3は、第 3実施形態のバイポーラ電池の好ましい一実施形態を示す断面図で ある。  FIG. 3 is a cross-sectional view showing a preferred embodiment of the bipolar battery of the third embodiment.
[図 4]図 4は、第 4実施形態の組電池を示す斜視図である。  FIG. 4 is a perspective view showing the assembled battery of the fourth embodiment.
[図 5]図 5は、第 4実施形態の組電池を搭載する第 5実施形態の自動車の概略図で ある。  [Fig. 5] Fig. 5 is a schematic view of the automobile of the fifth embodiment on which the assembled battery of the fourth embodiment is mounted.
[図 6]図 6は、バイポーラ型でないリチウムイオン二次電池の概要を示す断面図である  FIG. 6 is a cross-sectional view showing an outline of a lithium ion secondary battery that is not bipolar.
[図 7]図 7は、本発明の実施例の電池用電極における正極活物質層の空隙率と相対 出力の関係を示す図である。 FIG. 7 is a graph showing the relationship between the porosity of the positive electrode active material layer and the relative output in the battery electrode of the example of the present invention.
[図 8]図 8は、本発明の実施例および比較例の電池用電極における正極活物質層の 空隙率と相対出力の関係を示す図である。  FIG. 8 is a graph showing the relationship between the porosity of the positive electrode active material layer and the relative output in the battery electrodes of Examples and Comparative Examples of the present invention.
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0015] 以下、本発明の実施の形態を説明する。 Hereinafter, embodiments of the present invention will be described.
[0016] (第 1の実施形態） (構成） [0016] (First embodiment) (Constitution)
始めに、本発明の電池用電極の構造について、図面を参照して説明する。なお、 本発明においては、説明の都合上、図面が誇張されており、本発明の技術的範囲は 、図面に掲示する形態に限定されない。また、図面以外の実施形態も採用されうる。  First, the structure of the battery electrode of the present invention will be described with reference to the drawings. In the present invention, the drawings are exaggerated for convenience of explanation, and the technical scope of the present invention is not limited to the forms shown in the drawings. Also, embodiments other than the drawings may be employed.
[0017] 図 1は、本発明の電池用電極の一実施形態を示す断面図である。図 1に示す形態 の電池用電極 1は、集電体 11の一方の面に正極活物質層 13が形成され、他方の面 に負極活物質層 15が形成されてなるバイポーラ電極である。  FIG. 1 is a cross-sectional view showing one embodiment of a battery electrode of the present invention. The battery electrode 1 in the form shown in FIG. 1 is a bipolar electrode in which a positive electrode active material layer 13 is formed on one surface of a current collector 11 and a negative electrode active material layer 15 is formed on the other surface.
[0018] 本実施形態のバイポーラ電極において、正極活物質層 13に含まれる正極活物質 の平均粒子径は 5 μ m以下である。当該平均粒子径は、好ましくは 3 μ m以下であり 、より好ましくは 1 m以下である。なお、本発明の作用効果を得るという観点からは、 正極活物質の平均粒子径の下限値は特に制限されないが、電極内に導電ネットヮ ークを充分に形成させるという観点からは、正極活物質の平均粒子径は、好ましくは 0. 01 μ m以上であり、より好ましくは 0. 1 μ m以上である。また、本実施形態のバイ ポーラ電極において、正極活物質層 13の空隙率は 30%以上である。当該空隙率は 、好ましくは 33%以上であり、より好ましくは 35%以上である。なお、本発明の作用効 果を得るという観点力もは、正極活物質層 13の空隙率の上限値は特に制限されない 力 電池容量を向上させるという観点からは、正極活物質層 13の空隙率は、好ましく は 50 %以下であり、より好ましくは 45 %以下である。  In the bipolar electrode of this embodiment, the average particle diameter of the positive electrode active material contained in the positive electrode active material layer 13 is 5 μm or less. The average particle size is preferably 3 μm or less, more preferably 1 m or less. From the viewpoint of obtaining the effects of the present invention, the lower limit value of the average particle diameter of the positive electrode active material is not particularly limited, but from the viewpoint of sufficiently forming a conductive network in the electrode, the positive electrode active material. The average particle diameter of is preferably 0.01 μm or more, more preferably 0.1 μm or more. In the bipolar electrode of the present embodiment, the porosity of the positive electrode active material layer 13 is 30% or more. The porosity is preferably 33% or more, more preferably 35% or more. The upper limit of the porosity of the positive electrode active material layer 13 is not particularly limited from the viewpoint of obtaining the effect of the present invention. From the viewpoint of improving the battery capacity, the porosity of the positive electrode active material layer 13 is , Preferably 50% or less, more preferably 45% or less.
[0019] 一方、本実施形態のバイポーラ電極において、負極活物質層 15に含まれる負極 活物質の平均粒子径は 10 μ m以下である。当該平均粒子径は、好ましくは 5 μ m以 下であり、より好ましくは 1 μ m以下である。なお、本発明の作用効果を得るという観 点からは、負極活物質の平均粒子径の下限値は特に制限されないが、電極内に導 電ネットワークを充分に形成させるという観点からは、負極活物質の平均粒子径は、 好ましくは 0. 01 μ m以上であり、より好ましくは 0. 1 μ m以上である。また、本実施形 態のバイポーラ電極において、負極活物質層 15の空隙率は 50%以上である。当該 空隙率は、好ましくは 52%以上であり、より好ましくは 55%以上である。なお、本発明 の作用効果を得るという観点力もは、負極活物質層 15の空隙率の上限値は特に制 限されないが、電池容量を向上させるという観点力 は、負極活物質層 15の空隙率 は、好ましくは 80%以下であり、より好ましくは 70%以下である。 On the other hand, in the bipolar electrode of this embodiment, the average particle size of the negative electrode active material contained in the negative electrode active material layer 15 is 10 μm or less. The average particle size is preferably 5 μm or less, more preferably 1 μm or less. From the viewpoint of obtaining the effects of the present invention, the lower limit of the average particle diameter of the negative electrode active material is not particularly limited, but from the viewpoint of sufficiently forming a conductive network in the electrode, the negative electrode active material The average particle size of is preferably 0.01 μm or more, more preferably 0.1 μm or more. In the bipolar electrode of this embodiment, the porosity of the negative electrode active material layer 15 is 50% or more. The porosity is preferably 52% or more, more preferably 55% or more. The upper limit of the porosity of the negative electrode active material layer 15 is not particularly limited as to the viewpoint power to obtain the effects of the present invention, but the viewpoint power to improve battery capacity is not limited to the porosity of the negative electrode active material layer 15. Is preferably 80% or less, more preferably 70% or less.
[0020] 以上のような構成とすることにより、活物質粒子間の導電ネットワークが確保され、 一方、リチウムイオンの拡散経路もまた、充分に確保される。その結果、いずれかが 確保されなくなることによる電池の内部抵抗の増加が効果的に抑制されうる。なお、 本発明において、活物質の粒子径の値としては、粒度分布測定法により測定した値 を採用するものとする。また、活物質層の空隙率としては、下記数式 1に従って算出さ れる値を採用するものとする。 [0020] By adopting the above configuration, a conductive network between the active material particles is secured, while a lithium ion diffusion path is also sufficiently secured. As a result, an increase in the internal resistance of the battery due to the failure to secure either can be effectively suppressed. In the present invention, the value measured by the particle size distribution measurement method is adopted as the value of the particle diameter of the active material. As the porosity of the active material layer, a value calculated according to the following formula 1 shall be adopted.
[数 1]  [Number 1]
[数式 1 ] [Formula 1]
t I 電 密度 、、  t I Density,,
空隙率 [%] - (理論電極密度） 00 Porosity [ % ] -(Theoretical electrode density) 00
ここで、 電極密度 [ g/mL ] = ™あ ^スラリ_^¾ であり、 理論電極密度 [ g/mL ] =∑ (電極構成物質真密度 X活物質層内組成比)である。 Here, the electrode density [ g / mL] = ™ ^ slurry_ ^ ¾ , and the theoretical electrode density [g / mL] = ∑ (electrode constituent material true density X active material layer composition ratio).
[0021] 図 1に示す形態のノ ィポーラ電極は、例えば、バイポーラ型のリチウムイオン二次 電池（以下、単に「バイポーラ電池」とも称する）に採用されうる。その他の電池に採用 されても、勿論よい。なお、図 1に示す形態においては、正極および負極の双方にお いて、活物質の平均粒子径および活物質層の空隙が上述した所定の値であるが、 本発明の技術的範囲は力 うな形態のみには制限されず、正極または負極のいず れか一方のみが上述した所定の値を満足する形態もまた、包含しうる。 [0021] The nanopolar electrode of the form shown in FIG. 1 can be employed in, for example, a bipolar lithium ion secondary battery (hereinafter also simply referred to as “bipolar battery”). Of course, it may be adopted for other batteries. In the embodiment shown in FIG. 1, the average particle diameter of the active material and the voids of the active material layer are the above-described values in both the positive electrode and the negative electrode, but the technical scope of the present invention is powerful. The present invention is not limited only to the form, and a form in which only one of the positive electrode and the negative electrode satisfies the predetermined value described above can also be included.
[0022] 以下、リチウムイオン二次電池に採用される場合を例に挙げて、本発明の電池用電 極の構成について説明する。本実施形態の電池用電極は、正極および負極のそれ ぞれについて、活物質の平均粒子および活物質層の空隙率が所定の値である点に 特徴を有する。集電体、活物質の種類、バインダ、支持塩 (リチウム塩)、電解質、そ の他必要に応じて添加される化合物の選択について、特に制限はない。使用用途に 応じて、従来公知の知見を適宜参照することにより、選択すればよい。以下、本発明 の電池用電極を構成する部材について、詳細に説明する。 [0023] [集電体] [0022] The configuration of the battery electrode of the present invention will be described below by taking as an example a case where it is employed in a lithium ion secondary battery. The battery electrode of this embodiment is characterized in that the average particle of the active material and the porosity of the active material layer are predetermined values for each of the positive electrode and the negative electrode. There is no particular limitation on the selection of the current collector, the type of active material, the binder, the supporting salt (lithium salt), the electrolyte, and other compounds added as necessary. Depending on the intended use, it may be selected by appropriately referring to known knowledge. Hereinafter, the members constituting the battery electrode of the present invention will be described in detail. [0023] [Current collector]
集電体 11は、アルミニウム箔、ニッケル箔、銅箔、ステンレス（SUS)箔など、導電 性の材料から構成される。集電体の一般的な厚さは、 1〜30 mである。ただし、こ の範囲を外れる厚さの集電体を用いてもよい。集電体の大きさは、電池の使用用途 に応じて決定される。大型の電池に用いられる大型の電極を作製するのであれば、 面積の大きな集電体が用いられる。小型の電極を作製するのであれば、面積の小さ な集電体が用いられる。  The current collector 11 is made of a conductive material such as aluminum foil, nickel foil, copper foil, or stainless steel (SUS) foil. The typical thickness of the current collector is 1-30 m. However, a current collector having a thickness outside this range may be used. The size of the current collector is determined according to the intended use of the battery. If a large electrode used for a large battery is produced, a current collector with a large area is used. If a small electrode is produced, a current collector with a small area is used.
[0024] [活物質層] [0024] [Active material layer]
集電体 11上には、活物質層（13、 15)が形成される。活物質層（11、 15)は、充放 電反応の中心を担う活物質を含む層である。本発明においては、正極活物質層 13 もしくは負極活物質層 15の 、ずれか一方または双方にぉ 、て、活物質の平均粒子 径及び空隙率が上述した所定の値を満足する。  On the current collector 11, active material layers (13, 15) are formed. The active material layers (11, 15) are layers containing an active material that plays a central role in charge / discharge reactions. In the present invention, the average particle diameter and the porosity of the active material satisfy the above-described predetermined values for either one or both of the positive electrode active material layer 13 and the negative electrode active material layer 15.
[0025] 活物質層 (13, 15)は、活物質を含む。本発明の電極が正極として用いられる場合 には、活物質層は正極活物質を含む。一方、本発明の電極が負極として用いられる 場合には、活物質層は負極活物質を含む。 [0025] The active material layers (13, 15) include an active material. When the electrode of the present invention is used as a positive electrode, the active material layer contains a positive electrode active material. On the other hand, when the electrode of the present invention is used as a negative electrode, the active material layer contains a negative electrode active material.
[0026] 正極活物質としては、例えば、リチウム 遷移金属酸化物、リチウム 遷移金属リン 酸化合物、及びリチウム 遷移金属硫酸化合物などが例示される。場合によっては、[0026] Examples of the positive electrode active material include lithium transition metal oxides, lithium transition metal phosphate compounds, and lithium transition metal sulfate compounds. In some cases,
2種以上の正極活物質が併用されてもょ ヽ。 Two or more positive electrode active materials may be used in combination.
[0027] 負極活物質としては、例えば、炭素材料、リチウム 遷移金属化合物、金属材料、 及びリチウム 金属合金材料などが例示される。場合によっては、 2種以上の負極活 物質が併用されてもよい。 [0027] Examples of the negative electrode active material include carbon materials, lithium transition metal compounds, metal materials, and lithium metal alloy materials. In some cases, two or more negative electrode active materials may be used in combination.
[0028] 活物質層（13、 15)には、必要であれば、その他の物質が含まれてもよい。例えば[0028] The active material layers (13, 15) may contain other materials if necessary. For example
、導電助剤、バインダ、支持塩 (リチウム塩)、イオン伝導性ポリマー等が含まれうる。 また、イオン伝導性ポリマーが含まれる場合には、前記ポリマーを重合させるための 重合開始剤が含まれてもよ!/ヽ。 , Conductive aids, binders, supporting salts (lithium salts), ion conductive polymers, and the like. When an ion conductive polymer is included, a polymerization initiator for polymerizing the polymer may be included! / ヽ.
[0029] 導電助剤とは、活物質層の導電性を向上させるために配合される添加物をいう。導 電助剤としては、アセチレンブラック等のカーボンブラック、グラフアイトなどのカーボ ン粉末や、気相成長炭素繊維 (VGCF；登録商標)などの種々の炭素繊維などが挙 げられる。 [0029] The conductive auxiliary agent is an additive blended to improve the conductivity of the active material layer. Examples of conductive assistants include carbon black such as acetylene black, carbon powder such as graphite, and various carbon fibers such as vapor grown carbon fiber (VGCF (registered trademark)). I can get lost.
[0030] 本発明の電池用電極が正極として用いられる場合、換言すれば、電池用電極の正 極活物質層 13における活物質の平均粒子径および活物質層 13の空隙率が上述し た所定の値を満足する場合、正極活物質層 13は、正極活物質層 13の全質量に対し て 5質量％以上、より好ましくは 10質量％以上の導電助剤を含むことが望ましい。一 方、本発明の電池用電極が負極として用いられる場合、換言すれば、電池用電極の 負極活物質層 15における活物質の平均粒子径および活物質層の空隙率が上述し た所定の値を満足する場合、負極活物質層 15は、負極活物質層 15の全質量に対し て 1質量％以上、より好ましくは 5質量％以上の導電助剤を含むことが望ましい。  [0030] When the battery electrode of the present invention is used as a positive electrode, in other words, the average particle diameter of the active material in the positive electrode active material layer 13 of the battery electrode and the porosity of the active material layer 13 are the predetermined values described above. When the value of the positive electrode active material layer 13 is satisfied, the positive electrode active material layer 13 desirably contains 5% by mass or more, more preferably 10% by mass or more of the conductive auxiliary with respect to the total mass of the positive electrode active material layer 13. On the other hand, when the battery electrode of the present invention is used as a negative electrode, in other words, the average particle diameter of the active material and the porosity of the active material layer in the negative electrode active material layer 15 of the battery electrode are the predetermined values described above. Is satisfied, the negative electrode active material layer 15 preferably contains 1% by mass or more, more preferably 5% by mass or more of a conductive additive with respect to the total mass of the negative electrode active material layer 15.
[0031] ノインダとしては、ポリフッ化ビ-リデン (PVdF)、合成ゴム系バインダ等が挙げられ る。  [0031] Examples of the noinder include polyvinylidene fluoride (PVdF), a synthetic rubber binder, and the like.
[0032] 支持塩（リチウム塩）としては、 Li (C F SO ) N、 LiPF、 LiBF、 LiAsF、 LiCF  [0032] The supporting salt (lithium salt) includes Li (C F SO) N, LiPF, LiBF, LiAsF, LiCF
2 5 2 2 6 4 6 3 2 5 2 2 6 4 6 3
SO等が挙げられる。 SO etc. are mentioned.
3  Three
[0033] イオン伝導性ポリマーとしては、例えば、ポリエチレンォキシド (PEO)系及びポリプ ロピレンォキシド（PPO)系のポリマーが挙げられる。ここで、前記ポリマーは、本発明 の電極が採用される電池の電解質層にお 、て用いられるイオン伝導性ポリマーと同 じであってもよぐ異なっていてもよいが、同じであることが好ましい。  [0033] Examples of the ion conductive polymer include a polyethylene oxide (PEO) -based polymer and a polypropylene oxide (PPO) -based polymer. Here, the polymer may be the same as or different from the ion conductive polymer used in the electrolyte layer of the battery in which the electrode of the present invention is employed. preferable.
[0034] 重合開始剤は、イオン伝導性ポリマーの架橋性基に作用して、架橋反応を進行さ せるために配合される。開始剤として作用させるための外的要因に応じて、光重合開 始剤、熱重合開始剤などに分類される。重合開始剤としては、例えば、熱重合開始 剤であるァゾビスイソプチ口-トリル (AIBN)や、光重合開始剤であるべンジルジメチ ルケタール（BDK)等が挙げられる。  [0034] The polymerization initiator is blended so as to act on the crosslinkable group of the ion conductive polymer to advance the crosslinking reaction. Depending on the external factors to act as an initiator, it is classified into photopolymerization initiator, thermal polymerization initiator, etc. Examples of the polymerization initiator include azobisisoptyl-tolyl (AIBN), which is a thermal polymerization initiator, and benzyl dimethyl ketal (BDK), which is a photopolymerization initiator.
[0035] 活物質層（13、 15)に含まれる成分の配合比は、特に限定されない。配合比は、リ チウムイオン二次電池についての公知の知見を適宜参照することにより、調整されう る。  [0035] The mixing ratio of the components contained in the active material layers (13, 15) is not particularly limited. The blending ratio can be adjusted by appropriately referring to known knowledge about lithium ion secondary batteries.
[0036] 活物質層（13、 15)の厚さについても特に制限はなぐリチウムイオン二次電池に ついての従来公知の知見が適宜参照されうる。一例を挙げると、活物質層（13、 15) の厚さは、好ましくは 10〜： L00 m程度であり、より好ましくは 20〜50 mである。活 物質層（13、 15)が 10 /z m程度以上であれば、電池容量が充分に確保されうる。一 方、活物質層（13、 15)が 100 μ m程度以下であれば、電極深部 (集電体側）にリチ ゥムイオンが拡散しに《なることに伴う内部抵抗の増大という問題の発生が抑制され うる。 [0036] Conventionally known knowledge about a lithium ion secondary battery in which the thickness of the active material layer (13, 15) is not particularly limited can be appropriately referred to. For example, the thickness of the active material layer (13, 15) is preferably about 10 to about L00 m, and more preferably about 20 to 50 m. Life If the material layers (13, 15) are about 10 / zm or more, the battery capacity can be sufficiently secured. On the other hand, if the active material layer (13, 15) is about 100 μm or less, the problem of increased internal resistance due to diffusion of lithium ions to the electrode deep part (current collector side) is suppressed. Can be.
[0037] (第 2実施形態）  [0037] (Second Embodiment)
より好ましい形態において、本発明の電池用電極の活物質層（13、 15)は、 2層以 上カゝらなってもよい。以下、図面を参照しながら、正極活物質層 13および負極活物 質層 15のそれぞれが 2層からなる場合を例に挙げて、本発明の電極のより好ましい 形態を説明する。  In a more preferred embodiment, the active material layers (13, 15) of the battery electrode of the present invention may comprise two or more layers. Hereinafter, a more preferred embodiment of the electrode of the present invention will be described with reference to the drawings, taking as an example the case where each of the positive electrode active material layer 13 and the negative electrode active material layer 15 is composed of two layers.
[0038] 図 2は、本発明の電池用電極の他の実施形態を示す断面図である。図 2に示す形 態の電池用電極 1は、図 1に示す形態の電極と同様に、集電体 11の一方の面に正 極活物質層 13が形成され、他方の面に負極活物質層 15が形成されてなるバイポー ラ電極である。そして、図 2に示す形態の電池用電極 1は、正極活物質層 13および 負極活物質層 15のそれぞれにおいて、集電体 11と、上述した活物質の平均粒子径 および活物質層の空隙率の要件を満足する第 1の正極活物質層 (13a, 15a)との間 に、前記第 1の活物質層（13a、 15a)よりも空隙率の小さい第 2の活物質層（13b、 1 5b)が介在する点に特徴を有する。ここで、図 2に示す形態の電池用電極 1が電池に 採用される際には、前記第 2の活物質層（13b、 15b)が集電体 11側に位置し、前記 第 1の活物質層（13a、 15a)が電池の電解質側に位置する。力 うな形態によれば、 電解質側に空隙率のより大きい活物質層を配置することで、電極活物質層全体の深 部 (集電体 11側）にまでリチウムイオンを拡散させることが可能となる。その結果、電 池の内部抵抗 (主にリチウムイオンの拡散抵抗に起因）が低減されうる。一方、集電 体 11側に空隙率のより小さい活物質層を配置することで、電極活物質層全体の活物 質の充填率を確保することが可能となる。その結果、電池の容量特性および出力特 性が充分に確保されうる。  FIG. 2 is a cross-sectional view showing another embodiment of the battery electrode of the present invention. In the battery electrode 1 having the form shown in FIG. 2, the positive electrode active material layer 13 is formed on one surface of the current collector 11 and the negative electrode active material is formed on the other surface, similarly to the electrode having the form shown in FIG. This is a bipolar electrode in which the layer 15 is formed. Then, the battery electrode 1 having the form shown in FIG. 2 includes the current collector 11, the average particle diameter of the active material and the porosity of the active material layer described above in each of the positive electrode active material layer 13 and the negative electrode active material layer 15. The second active material layer (13b, 1a) having a lower porosity than the first active material layer (13a, 15a) between the first positive electrode active material layer (13a, 15a) that satisfies the above requirements 5b) is characterized by intervening. Here, when the battery electrode 1 having the form shown in FIG. 2 is employed in a battery, the second active material layer (13b, 15b) is located on the current collector 11 side, and the first active material layer Material layers (13a, 15a) are located on the electrolyte side of the battery. According to such a configuration, by disposing an active material layer with a higher porosity on the electrolyte side, it is possible to diffuse lithium ions deep into the entire electrode active material layer (current collector 11 side). Become. As a result, the internal resistance of the battery (mainly due to the diffusion resistance of lithium ions) can be reduced. On the other hand, by disposing an active material layer having a smaller porosity on the current collector 11 side, it is possible to ensure the filling rate of the active material in the entire electrode active material layer. As a result, the capacity characteristics and output characteristics of the battery can be sufficiently secured.
[0039] 図 2に示す形態において、第 1の活物質層 (13a, 15a)の具体的な形態は、上述し た通りであるため、ここでは詳細な説明は省略する。一方、第 2の活物質層（13b、 15 b)は、それぞれの空隙率が対応する第 1の活物質層（第 2の正極活物質層 13bにつ いては、第 1の正極活物質層 13a ;第 2の負極活物質層 15bについては、第 1の負極 活物質層 13a)よりも空隙率が小さ!/、のであれば、その他の具体的な形態は特に制 限されない。 [0039] In the form shown in Fig. 2, the specific form of the first active material layer (13a, 15a) is as described above, and thus detailed description thereof is omitted here. On the other hand, the second active material layer (13b, 15b) is connected to the first active material layer (second positive electrode active material layer 13b) corresponding to each porosity. The first positive electrode active material layer 13a; the second negative electrode active material layer 15b has a lower porosity than the first negative electrode active material layer 13a)! / The form is not particularly limited.
[0040] 図 2には、各活物質層（13、 15)がそれぞれ 2層からなる形態を図示したが、本発 明の技術的範囲はかような形態のみに制限されず、いずれか一方の活物質層が 1層 からなる形態や、 3層以上力もなる形態もまた、包含しうる。  FIG. 2 illustrates a form in which each of the active material layers (13, 15) is composed of two layers. However, the technical scope of the present invention is not limited to such a form, and either It is also possible to include a form in which the active material layer is composed of one layer or a form in which three or more layers of force are present.
[0041] (製造方法）  [0041] (Manufacturing method)
続いて、本発明の電池用電極の製造方法を説明する。  Then, the manufacturing method of the battery electrode of this invention is demonstrated.
[0042] まず、図 1に示す形態の電池用電極 1の製造方法について説明する。  First, a method for producing the battery electrode 1 having the configuration shown in FIG. 1 will be described.
[0043] 本発明の電極は、例えば、溶媒に、活物質を添加することにより、活物質スラリーを 調製し (活物質スラリー調製工程)、この活物質スラリーを集電体の表面に塗布し、乾 燥させることにより塗膜を形成し (塗膜形成工程)、前記塗膜形成工程を経て作製さ れた積層体を積層方向にプレスする（プレス工程)ことにより、製造されうる。活物質ス ラリーにイオン伝導性ポリマーが添加され、当該イオン伝導性ポリマーを架橋させる 目的で重合開始剤がさらに添加される場合には、塗膜形成工程における乾燥と同時 に、または当該乾燥の前もしくは後に、重合処理を施してもよい (重合工程)。  [0043] The electrode of the present invention, for example, prepares an active material slurry by adding an active material to a solvent (active material slurry preparation step), applies the active material slurry to the surface of the current collector, It can be produced by forming a coating film by drying (coating film forming process) and pressing the laminate produced through the coating film forming process in the laminating direction (pressing process). When an ion conductive polymer is added to the active material slurry and a polymerization initiator is further added for the purpose of cross-linking the ion conductive polymer, at the same time as drying in the coating film forming process or before the drying. Alternatively, a polymerization treatment may be performed later (polymerization step).
[0044] 以下、力 うな製造方法について、工程順に説明するが、下記の形態のみには制 限されない。  [0044] Hereinafter, a powerful manufacturing method will be described in the order of steps, but the present invention is not limited to the following forms.
[0045] [活物質スラリー調製工程]  [0045] [Active material slurry preparation step]
本工程においては、所望の活物質、および必要に応じて他の成分 (例えば、導電 助剤、ノインダ、イオン伝導性ポリマー、支持塩 (リチウム塩)、重合開始剤など)を、 溶媒中で混合して、活物質スラリーを調製する。この活物質スラリー中に配合される 各成分の具体的な形態については、上記の本発明の電極の構成の欄において説明 した通りであるため、ここでは詳細な説明は省略する。  In this step, the desired active material and other components (for example, conductive assistant, noda, ion conductive polymer, supporting salt (lithium salt), polymerization initiator, etc.) are mixed in a solvent as necessary. Then, an active material slurry is prepared. The specific form of each component blended in the active material slurry is as described in the column of the configuration of the electrode of the present invention, and a detailed description is omitted here.
[0046] 溶媒の種類や混合手段は特に制限されず、電極製造について従来公知の知見が 適宜参照されうる。溶媒の一例を挙げると、 N—メチルー 2—ピロリドン (NMP)、ジメ チルホルムアミド、ジメチルァセトアミド、メチルホルムアミドなどが用いられうる。バイ ンダとしてポリフッ化ビ-リデン (PVdF)を採用する場合には、 NMPを溶媒として用 いるとよい。 [0046] The type of solvent and the mixing means are not particularly limited, and conventionally known knowledge about electrode production can be appropriately referred to. As an example of the solvent, N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, methylformamide and the like can be used. When using polyvinylidene fluoride (PVdF) as the binder, NMP is used as the solvent. It is good to be.
[0047] 本製造方法では、この活物質スラリー調製工程において調製される活物質スラリー 中の固形分と溶媒との配合比を調整することにより、製造される電極の活物質層の空 隙率を制御することも可能である。具体的には、形成される活物質層の空隙率を減 少させたい場合には、活物質スラリー中の固形分の配合量を増カロさせるとよい。一方 、形成される活物質層の空隙率を増加させたい場合には、活物質スラリー中の固形 分の配合量を減少させるとよい。ただし、後述する塗布工程やプレス工程において、 活物質層の空隙率を制御してもよい。  [0047] In this production method, the porosity of the active material layer of the produced electrode is adjusted by adjusting the mixing ratio of the solid content and the solvent in the active material slurry prepared in the active material slurry preparation step. It is also possible to control. Specifically, when it is desired to reduce the porosity of the formed active material layer, the amount of solid content in the active material slurry should be increased. On the other hand, when it is desired to increase the porosity of the active material layer to be formed, the blending amount of the solid content in the active material slurry is preferably decreased. However, the porosity of the active material layer may be controlled in a coating process and a pressing process described later.
[0048] [塗膜形成工程]  [0048] [Coating film forming step]
続いて、集電体を準備し、上記で調製した活物質スラリーを当該集電体の表面に 塗布し、乾燥させる。これにより、集電体表面に活物質スラリーからなる塗膜が形成さ れる。この塗膜は、後述するプレス工程を経て、活物質層となる。  Subsequently, a current collector is prepared, and the active material slurry prepared above is applied to the surface of the current collector and dried. As a result, a coating film made of the active material slurry is formed on the surface of the current collector. This coating film becomes an active material layer through a pressing step described later.
[0049] 準備する集電体の具体的な形態については、上記の本発明の電極の構成の欄に ぉ ヽて説明した通りであるため、ここでは詳細な説明は省略する。  [0049] Since the specific form of the current collector to be prepared is as described above in the section of the electrode configuration of the present invention, a detailed description is omitted here.
[0050] 活物質スラリーを塗布するための塗布手段も特に限定されない。例えば、自走型コ ータなどの一般的に用いられる手段が採用されうる。ただし、塗布手段として、インク ジェット方式を用いると、より精密な調節が可能となる結果、より簡便に活物質層の空 隙率が制御されうるため、好ましい。  [0050] The application means for applying the active material slurry is not particularly limited. For example, a commonly used means such as a self-propelled coater can be adopted. However, it is preferable to use an ink jet method as a coating unit because finer adjustment is possible and the porosity of the active material layer can be more easily controlled.
[0051] 塗膜は、製造される電極における集電体と活物質層との所望の配置形態に応じて 、形成される。例えば、製造される電極力 Sバイポーラ電極の場合、集電体の一方の面 には正極活物質を含む塗膜が形成され、他方の面には負極活物質を含む塗膜が形 成される。これに対し、ノ ィポーラ型でない電極を製造する場合には、正極活物質ま たは負極活物質のいずれか一方を含む塗膜が 1枚の集電体の両面に形成される。  [0051] The coating film is formed according to a desired arrangement of the current collector and the active material layer in the manufactured electrode. For example, in the case of a manufactured electrode force S bipolar electrode, a coating film containing a positive electrode active material is formed on one surface of the current collector, and a coating film containing a negative electrode active material is formed on the other surface. . On the other hand, when manufacturing a non-polar electrode, a coating film containing either the positive electrode active material or the negative electrode active material is formed on both surfaces of one current collector.
[0052] その後、集電体の表面に形成された塗膜を乾燥させる。これにより、塗膜中の溶媒 が除去される。  [0052] Thereafter, the coating film formed on the surface of the current collector is dried. Thereby, the solvent in the coating film is removed.
[0053] 塗膜を乾燥させるための乾燥手段も特に制限されず、電極製造について従来公知 の知見が適宜参照されうる。例えば、加熱処理が例示される。乾燥条件 (乾燥時間、 乾燥温度など）は、活物質スラリーの塗布量やスラリーの溶媒の揮発速度に応じて適 宜設定されうる。 [0053] The drying means for drying the coating film is not particularly limited, and conventionally known knowledge about electrode production can be appropriately referred to. For example, heat treatment is exemplified. The drying conditions (drying time, drying temperature, etc.) are suitable for the amount of active material slurry applied and the volatilization rate of the solvent in the slurry. Can be set appropriately.
[0054] 塗膜が重合開始剤を含む場合には、さらに重合工程を行うことで、塗膜中のイオン 伝導性ポリマーが架橋性基によって架橋される。  [0054] When the coating film contains a polymerization initiator, the ion conductive polymer in the coating film is cross-linked by a crosslinkable group by further performing a polymerization step.
[0055] 重合工程における重合処理も特に制限されることはなぐ従来公知の知見を適宜 参照すればよい。例えば、塗膜が熱重合開始剤 (AIBNなど)を含む場合には、塗膜 に熱処理を施す。また、塗膜が光重合開始剤 (BDKなど)を含む場合には、紫外光 などの光を照射する。なお、熱重合のための熱処理は、上記の乾燥工程と同時に行 われてもょ 、し、当該乾燥工程の前または後に行われてもよ 、。  [0055] The polymerization treatment in the polymerization step is not particularly limited, and conventionally known knowledge may be referred to as appropriate. For example, when the coating film contains a thermal polymerization initiator (AIBN, etc.), the coating film is heat treated. In addition, when the coating film contains a photopolymerization initiator (BDK, etc.), light such as ultraviolet light is irradiated. The heat treatment for thermal polymerization may be performed at the same time as the above drying step, or may be performed before or after the drying step.
[0056] [プレス工程]  [0056] [Pressing process]
続いて、前記塗膜形成工程を経て作製された積層体を積層方向にプレスする。こ れにより、本発明の電池用電極が完成する。この際、プレス条件を調節することにより 、活物質層の空隙率が制御されうる。  Then, the laminated body produced through the said coating-film formation process is pressed to the lamination direction. Thereby, the battery electrode of the present invention is completed. At this time, the porosity of the active material layer can be controlled by adjusting the pressing conditions.
[0057] プレス処理の具体的な手段やプレス条件は特に制限されず、プレス処理後の活物 質層の空隙率が所望の値となるように、適宜調節されうる。プレス処理の具体的な形 態としては、例えば、ホットプレス機やカレンダーロールプレス機などが挙げられる。ま た、プレス条件 (温度、圧力など)も特に制限される、従来公知の知見が適宜参照さ れうる。  [0057] Specific means and press conditions for the press treatment are not particularly limited, and can be appropriately adjusted so that the porosity of the active material layer after the press treatment becomes a desired value. Specific examples of the press process include a hot press machine and a calendar roll press machine. In addition, conventionally known knowledge, in which pressing conditions (temperature, pressure, etc.) are particularly limited, can be referred to as appropriate.
[0058] 本願は、図 2に示す好ましい形態の電池用電極の製造方法を提供する。すなわち 、本発明に係る電池用電極の製造方法は、溶媒に活物質を添加することにより、活 物質を含む活物質スラリーを調製する活物質スラリー調製工程と、集電体の表面に 前記活物質スラリーを塗布し、乾燥させることにより塗膜を形成する塗膜形成工程と、 前記塗膜形成工程を経て作製された積層体を積層方向にプレスするプレス工程と、 前記塗膜形成工程と前記プレス工程との組み合わせ工程を 2回以上繰り返すことを 特徴とする。  [0058] The present application provides a method of manufacturing a battery electrode of a preferred form shown in FIG. That is, the battery electrode manufacturing method according to the present invention includes an active material slurry preparation step of preparing an active material slurry containing an active material by adding the active material to a solvent, and the active material on the surface of the current collector. A coating film forming process for forming a coating film by applying slurry and drying; a pressing process for pressing the laminate produced through the coating film forming process in the stacking direction; and the coating film forming process and the press It is characterized by repeating the combination process with the process twice or more.
[0059] 当該製造方法は、 2層以上力 なる活物質層の各層の空隙率を制御することを目 的として、前記塗膜形成工程と前記プレス工程との組み合わせ工程を 2回以上繰り 返す点に特徴を有する。換言すれば、まず、集電体 11の表面に塗膜を形成し（1回 目の塗膜形成工程）、プレスする（1回目のプレス工程)。これにより、図 2に示す第 2 の活物質層（13b、 15b)が形成される。続いて、当該第 2の活物質層の表面に再度 塗膜を形成し (2回目の塗膜形成工程)、プレスする（2回目のプレス工程)。これによ り、図 2に示す第 1の活物質層（13a、 15a)が形成され、図 2に示す形態の電池用電 極が完成する。 [0059] The manufacturing method repeats the combination step of the coating film forming step and the pressing step twice or more for the purpose of controlling the porosity of each layer of the active material layer having two or more layers. It has the characteristics. In other words, first, a coating film is formed on the surface of the current collector 11 (first coating film forming process) and pressed (first pressing process). As a result, the second shown in FIG. Active material layers (13b, 15b) are formed. Subsequently, a coating film is formed again on the surface of the second active material layer (second coating film forming process) and pressed (second pressing process). As a result, the first active material layers (13a, 15a) shown in FIG. 2 are formed, and the battery electrode having the configuration shown in FIG. 2 is completed.
[0060] 前記組み合わせ工程を繰り返す場合、 n+ 1回目（n≥ 1)のプレス工程におけるプ レス圧力は、 n回目のプレス工程におけるプレス圧力よりも小さく設定することが好ま しい。上述した製造方法を例に挙げて具体的に説明すれば、 2回目のプレス工程に おけるプレス圧力を 1回目のプレス工程におけるプレス圧力よりも小さくするとよいの である。こうすることで、 2回目のプレス工程により形成される第 1の活物質層（13a、 1 5a)の空隙率が、 1回目のプレス工程により形成される第 2の活物質層（13b、 15b) の空隙率よりも小さい値に制御され、図 2に示す形態の電池用電極が作製されうる。  [0060] When the combination process is repeated, it is preferable that the press pressure in the (n + 1) th press process (n≥1) is set smaller than the press pressure in the nth press process. If the manufacturing method described above is taken as an example, the pressing pressure in the second pressing step should be made smaller than the pressing pressure in the first pressing step. In this way, the porosity of the first active material layer (13a, 15a) formed by the second pressing process is changed to the second active material layer (13b, 15b) formed by the first pressing process. 2), the battery electrode having the configuration shown in FIG. 2 can be produced.
[0061] (第 3実施形態）  [0061] (Third embodiment)
第 3実施形態では、上記の第 1実施形態または第 2実施形態の電池用電極を用い て、リチウムイオン二次電池を構成する。すなわち、本発明の第 3は、正極、電解質 層、および負極力 Sこの順に積層されてなる少なくとも 1つの単電池層を含むリチウムィ オン二次電池であって、前記正極または前記負極の少なくとも一方が本発明の電池 用電極である、リチウムイオン電池である。本発明の電極は、正極、負極、バイポーラ 電極のいずれにも適用されうる。本発明の電極を、少なくとも 1つの電極として含むリ チウムイオン二次電池は、本発明の技術的範囲に属する。ただし、好ましくは、リチウ ムイオン二次電池を構成する電極の全てが本発明の電極である。カゝような構成を採 用することにより、リチウムイオン二次電池の出力特性を効果的に向上させうる。  In the third embodiment, a lithium ion secondary battery is configured using the battery electrode of the first embodiment or the second embodiment. That is, a third aspect of the present invention is a lithium-ion secondary battery including at least one single battery layer laminated in this order, the positive electrode, the electrolyte layer, and the negative electrode force S, and at least one of the positive electrode or the negative electrode is It is a lithium ion battery which is an electrode for a battery of the present invention. The electrode of the present invention can be applied to any of a positive electrode, a negative electrode, and a bipolar electrode. A lithium ion secondary battery including the electrode of the present invention as at least one electrode belongs to the technical scope of the present invention. However, preferably, all of the electrodes constituting the lithium ion secondary battery are the electrodes of the present invention. By adopting such a configuration, the output characteristics of the lithium ion secondary battery can be effectively improved.
[0062] 本発明の電池は、バイポーラ型のリチウムイオン二次電池（以下、バイポーラ電池） とも称する）でありうる。図 3は、バイポーラ電池である、本発明の第 3のリチウムイオン 二次電池を示す断面図である。以下、図 3に示すバイポーラ電池を例に挙げて詳細 に説明するが、本発明の技術的刃には力 うな形態のみに制限されない。  [0062] The battery of the present invention may be a bipolar lithium ion secondary battery (hereinafter also referred to as a bipolar battery). FIG. 3 is a cross-sectional view showing a third lithium ion secondary battery of the present invention, which is a bipolar battery. Hereinafter, the bipolar battery shown in FIG. 3 will be described in detail as an example. However, the technical blade of the present invention is not limited to only a powerful form.
[0063] 図 3に示す本実施形態のバイポーラ電池 10は、実際に充放電反応が進行する略 矩形の電池要素 21が、外装であるラミネートシート 29の内部に封止された構造を有 する。 [0064] 図 3に示すように、本実施形態のバイポーラ電池 10の電池要素 21は、正極活物質 層 13と、負極活物質相違 15とが集電体 11のそれぞれの面に形成されたバイポーラ 電極（図 1に示す形態のバイポーラ電極)を複数個有する。各バイポーラ電極は、電 解質層 17を介して積層されて電池要素 21を形成する。この際、一のバイポーラ電極 の正極活物質層 13と前記一のノ ィポーラ電極に隣接する他のバイポーラ電極の負 極活物質層 15とが電解質層 17を介して向き合うように、各バイポーラ電極および電 解質層 1が積層されている。 The bipolar battery 10 of the present embodiment shown in FIG. 3 has a structure in which a substantially rectangular battery element 21 in which a charge / discharge reaction actually proceeds is sealed inside a laminate sheet 29 that is an exterior. As shown in FIG. 3, the battery element 21 of the bipolar battery 10 of the present embodiment includes a bipolar element in which a positive electrode active material layer 13 and a negative electrode active material difference 15 are formed on each surface of a current collector 11. It has a plurality of electrodes (bipolar electrodes of the form shown in FIG. 1). Each bipolar electrode is laminated via an electrolyte layer 17 to form a battery element 21. At this time, each of the bipolar electrodes and the positive electrode active material layer 13 of one bipolar electrode and the negative electrode active material layer 15 of another bipolar electrode adjacent to the one bipolar electrode face each other through the electrolyte layer 17. The electrolyte layer 1 is laminated.
[0065] そして、隣接する正極活物質層 13、電解質層 17、および負極活物質層 15は、一 つの単電池層 19を構成する。従って、バイポーラ電池 10は、単電池層 19が積層さ れてなる構成を有するともいえる。また、単電池層 19の外周には、隣接する集電体 1 1間を絶縁するための絶縁層 31が設けられている。なお、電池要素 21の最外層に位 置する集電体 (最外層集電体） (11a, l ib)には、片面のみに、正極活物質層 13 (正 極側最外層集電体 1 la)または負極活物質層 15 (負極側最外層集電体 1 lb)の ヽず れか一方が形成されて!、る。  Then, the adjacent positive electrode active material layer 13, electrolyte layer 17, and negative electrode active material layer 15 constitute one unit cell layer 19. Accordingly, it can be said that the bipolar battery 10 has a configuration in which the unit cell layers 19 are laminated. In addition, an insulating layer 31 for insulating the adjacent current collectors 11 is provided on the outer periphery of the unit cell layer 19. The current collector (outermost layer current collector) (11a, ib) positioned on the outermost layer of the battery element 21 has a positive electrode active material layer 13 (positive electrode side outermost layer current collector 1) on only one side. la) or negative electrode active material layer 15 (negative electrode side outermost layer current collector 1 lb) is formed!
[0066] さらに、図 3に示すバイポーラ電池 10では、正極側最外層集電体 11aが延長され て正極タブ 25とされ、外装であるラミネートシート 29から導出している。一方、負極側 最外層集電体 1 lbが延長されて負極タブ 27とされ、同様にラミネートシート 29から導 出している。  Further, in the bipolar battery 10 shown in FIG. 3, the positive electrode side outermost layer current collector 11a is extended to form a positive electrode tab 25, which is led out from a laminate sheet 29 which is an exterior. On the other hand, 1 lb of the negative electrode side outermost layer current collector is extended to form a negative electrode tab 27, which is similarly led out from the laminate sheet 29.
[0067] 以下、本実施形態のバイポーラ電池 10を構成する部材について簡単に説明する。  Hereinafter, members constituting the bipolar battery 10 of the present embodiment will be briefly described.
ただし、電極を構成する成分については上記で説明した通りであるため、ここでは説 明を省略する。また、本発明の技術的範囲が下記の形態のみに制限されることはなく 、従来公知の形態が同様に採用されうる。  However, since the components constituting the electrode are as described above, description thereof is omitted here. Further, the technical scope of the present invention is not limited to the following forms, and conventionally known forms can be similarly adopted.
[0068] [電解質層]  [0068] [Electrolyte layer]
電解質層 17を構成する電解質としては、液体電解質またはポリマー電解質が用い られうる。  As the electrolyte constituting the electrolyte layer 17, a liquid electrolyte or a polymer electrolyte can be used.
[0069] 液体電解質は、可塑剤である有機溶媒に支持塩であるリチウム塩が溶解した形態 を有する。可塑剤として用いられうる有機溶媒としては、例えば、エチレンカーボネー ト（EC)やプロプレンカーボネート（PC)等のカーボネート類が例示される。また、支 持塩 (リチウム塩）としては、 LiBETI等の電極の活物質層に添加されうる化合物が同 様に採用されうる。 [0069] The liquid electrolyte has a form in which a lithium salt as a supporting salt is dissolved in an organic solvent as a plasticizer. Examples of the organic solvent that can be used as the plasticizer include carbonates such as ethylene carbonate (EC) and propylene carbonate (PC). Also, support As the supported salt (lithium salt), a compound that can be added to the active material layer of the electrode, such as LiBETI, can be similarly employed.
[0070] 一方、ポリマー電解質は、電解液を含むゲル電解質と、電解液を含まな ヽ真性ポリ マー電解質に分類される。  [0070] On the other hand, polymer electrolytes are classified into gel electrolytes containing an electrolytic solution and authentic polymer electrolytes containing no electrolytic solution.
[0071] ゲル電解質は、イオン伝導性ポリマー力もなるマトリックスポリマーに、上記の液体 電解質が注入されてなる構成を有する。マトリックスポリマーとして用いられるイオン伝 導 ¾ポリマーとしては、例えば、ポリエチレンォキシド (PEO)、ポリプロピレンォキシド (PPO)、およびこれらの共重合体等が挙げられる。力ようなポリアルキレンォキシド系 高分子には、リチウム塩などの電解質塩がよく溶解しうる。  [0071] The gel electrolyte has a configuration in which the above-described liquid electrolyte is injected into a matrix polymer having ion-conductive polymer power. Examples of the ion conductive polymer used as the matrix polymer include polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof. Electrolyte salts such as lithium salts can be well dissolved in such polyalkylene oxide polymers.
[0072] なお、電解質層 17が液体電解質やゲル電解質から構成される場合には、電解質 層 17にセパレータを用いてもよい。セパレータの具体的な形態としては、例えば、ポ リエチレンやポリプロピレン等のポリオレフインカもなる微多孔膜が挙げられる。  [0072] When the electrolyte layer 17 is composed of a liquid electrolyte or a gel electrolyte, a separator may be used for the electrolyte layer 17. As a specific form of the separator, for example, a microporous film that is also a polyolefin linker such as polyethylene or polypropylene can be cited.
[0073] 真性ポリマー電解質は、上記のマトリックスポリマーに支持塩 (リチウム塩）が溶解し てなる構成を有し、可塑性である有機溶媒を含まない。従って、電解質層 17が真性 ポリマー電解質から構成される場合には電池からの液漏れの心配がなぐ電池の信 頼性が向上しうる。  [0073] The intrinsic polymer electrolyte has a structure in which a supporting salt (lithium salt) is dissolved in the above matrix polymer, and does not contain a plastic organic solvent. Therefore, when the electrolyte layer 17 is made of an intrinsic polymer electrolyte, the reliability of the battery can be improved without worrying about the leakage of liquid from the battery.
[0074] ゲル電解質や真性ポリマー電解質のマトリックスポリマーは、架橋構造を形成するこ とによって、優れた機械的強度を発現しうる。架橋構造を形成させるには、適当な重 合開始剤を用いて、高分子電解質形成用の重合性ポリマー（例えば、 PEOや PPO) に対して熱重合、紫外線重合、放射線重合、電子線重合等の重合処理を施せばよ い。  [0074] The matrix polymer of the gel electrolyte or the intrinsic polymer electrolyte can exhibit excellent mechanical strength by forming a crosslinked structure. In order to form a crosslinked structure, thermal polymerization, ultraviolet polymerization, radiation polymerization, electron beam polymerization, etc. are performed on a polymerizable polymer (for example, PEO or PPO) for forming a polyelectrolyte using an appropriate polymerization initiator. The polymerization process may be performed.
[0075] [絶縁層]  [0075] [Insulating layer]
ノ ィポーラ電池 10においては、通常、各単電池層 19の周囲に絶縁層 31が設けら れる。この絶縁層 31は、電池内で隣り合う集電体 11同士が接触したり、電池要素 21 における単電池層 19の端部の僅かな不ぞろいなどによる短絡が起きたりするのを防 止する目的で設けられる。力 うな絶縁層 31の設置により、長期間の信頼性および 安全性が確保され、高品質のバイポーラ電池 10が提供されうる。  In the bipolar battery 10, an insulating layer 31 is usually provided around each unit cell layer 19. This insulating layer 31 is intended to prevent the adjacent current collectors 11 in the battery from contacting each other and short-circuiting due to slight unevenness at the end of the cell layer 19 in the battery element 21 or the like. Provided. The installation of a strong insulating layer 31 ensures long-term reliability and safety, and can provide a high-quality bipolar battery 10.
[0076] 絶縁層 31としては、絶縁性、固定電解質の脱落に対するシール性や外部からの水 分の透湿に対するシール性 (密封性)、電池動作温度下での耐熱性などを有するも のであればよぐ例えば、ウレタン榭脂、エポキシ榭脂、ポリエチレン榭脂、ポリプロピ レン榭脂、ポリイミド榭脂、ゴムなどが用いられうる。なかでも、耐蝕性、耐薬品性、作 り易さ (製膜性)、経済性などの観点から、ウレタン榭脂、エポキシ榭脂が好ましい。 [0076] The insulating layer 31 has an insulating property, a sealing property against falling off of the fixed electrolyte, and water from the outside. For example, urethane resin, epoxy resin, polyethylene resin, polypropylene resin, polyimide resin can be used as long as they have a sealing property against moisture permeation (sealing property) and heat resistance under battery operating temperature. Fats, rubbers and the like can be used. Of these, urethane resin and epoxy resin are preferred from the viewpoints of corrosion resistance, chemical resistance, ease of production (film forming property), and economical efficiency.
[0077] [タブ] [0077] [Tab]
バイポーラ電池 10においては、電池外部に電流を取り出す目的で、最外層集電体 (11a, l ib)に電気的に接続されたタブ (正極タブ 25および負極タブ 27)が外装の 外部に取り出される。具体的には、正極用最外層集電体 11aに電気的に接続された 正極タブ 25と、負極側最外層集電体 l ibに電気的に接続された負極タブ 27とが、 外装の外部に取り出される。  In the bipolar battery 10, the tabs (positive electrode tab 25 and negative electrode tab 27) electrically connected to the outermost current collector (11a, ib) are taken out of the exterior for the purpose of taking out the current outside the battery. . Specifically, the positive electrode tab 25 electrically connected to the positive electrode outermost layer current collector 11a and the negative electrode tab 27 electrically connected to the negative electrode side outermost layer current collector l ib are external to the exterior. To be taken out.
[0078] タブ (正極タブ 25および負極タブ 27)の材質は、特に制限されず、バイポーラ電池 用のタブとして従来用いられている公知の材質が用いられうる。例えば、アルミニウム 、銅、チタン、ニッケル、ステンレス鋼（SUS)、これらの合金等が例示される。なお、 正極タブ 25と負極タブ 27とでは、同一の材質が用いられてもよいし、異なる材質が 用いられてもよい。なお、本実施形態のように、最外層集電体（l la、 l ib)を延長す ることによりタブ (25、 27)としてもよいし、別途準備した最外層集電体に接続してもよ い。 [0078] The material of the tabs (positive electrode tab 25 and negative electrode tab 27) is not particularly limited, and a known material conventionally used as a tab for a bipolar battery can be used. For example, aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof are exemplified. The positive electrode tab 25 and the negative electrode tab 27 may be made of the same material or different materials. As in this embodiment, the outermost layer current collector (l la, ib) may be extended to form tabs (25, 27), or may be connected to a separately prepared outermost layer current collector. It's good.
[0079] [外装]  [0079] [Exterior]
ノ ィポーラ電池 10においては、使用時の外部からの衝撃や環境劣化を防止するた めに、電池要素 21は、好ましくはラミネートシート 29等の外装内に収容される。外装 としては特に制限されず、従来公知の外装が用いられうる。自動車の熱源から効率よ く熱を伝え、電池内部を迅速に電池動作温度まで加熱しうる点で、好ましくは、熱伝 導性に優れた高分子 金属複合ラミネートシート等が用いられうる。  In the nopolar battery 10, the battery element 21 is preferably housed in an exterior such as a laminate sheet 29 in order to prevent external impact and environmental degradation during use. The exterior is not particularly limited, and a conventionally known exterior can be used. From the viewpoint of efficiently transferring heat from a heat source of an automobile and quickly heating the inside of the battery to the battery operating temperature, a polymer metal composite laminate sheet having excellent heat conductivity can be preferably used.
[0080] (第 4実施形態） [0080] (Fourth embodiment)
第 4実施形態では、上記の第 3実施形態のバイポーラ電池を複数個、並列および Zまたは直列に接続して、組電池を構成する。  In the fourth embodiment, an assembled battery is configured by connecting a plurality of the bipolar batteries of the above-described third embodiment in parallel and Z or in series.
[0081] 図 4は、本実施形態の組電池を示す斜視図である。 FIG. 4 is a perspective view showing the assembled battery of this embodiment.
[0082] 図 4に示すように、組電池 40は、上記の第 2実施形態に記載のバイポーラ電池が 複数個接続されることにより構成される。各バイポーラ電池 10の正極タブ 25および負 極タブ 27がバスバーを用いて接続されることにより、各バイポーラ電池 10が接続され ている。組電池 40の一の側面には、組電池 40全体の電極として、電極ターミナル（4 2、 43)が設けられている。 As shown in FIG. 4, the assembled battery 40 is the bipolar battery described in the second embodiment. It is configured by connecting a plurality. Each bipolar battery 10 is connected by connecting the positive electrode tab 25 and the negative electrode tab 27 of each bipolar battery 10 using a bus bar. On one side surface of the assembled battery 40, electrode terminals (42, 43) are provided as electrodes of the assembled battery 40 as a whole.
[0083] 組電池 40を構成する複数個のバイポーラ電池 10を接続する際の接続方法は特に 制限されず、従来公知の手法が適宜採用されうる。例えば、超音波溶接、スポット溶 接などの溶接を用いる方法や、リベット、カシメなどを用いて固定する手法が採用され うる。力 うな接続方法によれば、組電池 40の長期信頼性が向上しうる。  [0083] The connection method for connecting the plurality of bipolar batteries 10 constituting the assembled battery 40 is not particularly limited, and a conventionally known method can be appropriately employed. For example, a method using welding such as ultrasonic welding or spot welding, or a method of fixing using rivets or caulking can be employed. According to the powerful connection method, the long-term reliability of the assembled battery 40 can be improved.
[0084] 本実施形態の組電池 40によれば、組電池 40を構成する個々のバイポーラ電池 10 が出力特性に優れることから、出力特性に優れる組電池が提供されうる。  [0084] According to the assembled battery 40 of the present embodiment, the individual bipolar batteries 10 constituting the assembled battery 40 are excellent in output characteristics, and therefore an assembled battery excellent in output characteristics can be provided.
[0085] なお、組電池 40を構成するバイポーラ電池 10の接続は、複数個全て並列に接続 してもよく、また、複数個全て直列に接続してもよぐさら〖こ、直列接続と並列接続とを 組み合わせてもよい。  [0085] It should be noted that all of the bipolar batteries 10 constituting the assembled battery 40 may be connected in parallel, or all of the plurality of bipolar batteries 10 may be connected in series. You may combine the connection.
[0086] (第 5実施形態）  [0086] (Fifth embodiment)
第 5実施形態では、上記の第 3実施形態のバイポーラ電池 10、または第 4実施形 態の組電池 40をモータ駆動用電源として搭載して、車両を構成する。バイポーラ電 池 10または組電池 40をモータ用電源として用いる車両としては、例えば、ガソリンを 用いな!/、完全電気自動車、シリーズハイブリッド自動車やパラレルハイブリッド自動車 などのハイブリッド自動車、および燃料電池自動車などの、車両をモータによって駆 動する自動車が挙げられる。  In the fifth embodiment, the bipolar battery 10 of the third embodiment or the assembled battery 40 of the fourth embodiment is mounted as a motor driving power source to constitute a vehicle. Vehicles that use the bipolar battery 10 or the assembled battery 40 as a motor power source include, for example, gasoline! /, Fully electric vehicles, hybrid vehicles such as series hybrid vehicles and parallel hybrid vehicles, and fuel cell vehicles. One example is an automobile that drives a vehicle by a motor.
[0087] 参考までに、図 5に、組電池 40を搭載する自動車 50の概略図を示す。自動車 50 に搭載される組電池 40は、上記で説明したような特性を有する。このため、組電池 4 0を搭載する自動車 50は出力特性に優れ、高出力条件下においても充分な出力を 提供しうる。  [0087] For reference, FIG. 5 shows a schematic diagram of an automobile 50 in which the assembled battery 40 is mounted. The assembled battery 40 mounted on the automobile 50 has the characteristics as described above. Therefore, the automobile 50 equipped with the assembled battery 40 has excellent output characteristics and can provide sufficient output even under high output conditions.
[0088] 以上のように、本発明の幾つかの好適な実施形態について示したが、本発明は、 以上の実施形態に限られるものではなぐ当業者によって種々の変更、省略、及び 追カ卩が可能である。例えば、上記の第 3実施形態では、バイポーラ型のリチウムィォ ン二次電池 (バイポーラ電池）を例に挙げて説明した力 本発明の電池の技術的範 囲がバイポーラ電池のみに制限されることはなぐ例えば、バイポーラ型でないリチウ ムイオン二次電池であってもよい。参考までに、図 6に、バイポーラ型でないリチウム イオン二次電池 60の概要を示す断面図を示す。 As described above, some preferred embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and various modifications, omissions, and additional features can be made by those skilled in the art. Is possible. For example, in the third embodiment described above, the power described by taking a bipolar lithium-ion battery (bipolar battery) as an example. Technical scope of the battery of the present invention For example, a lithium ion secondary battery that is not a bipolar type may be used. For reference, FIG. 6 shows a cross-sectional view showing an outline of a non-bipolar lithium ion secondary battery 60.
実施例  Example
[0089] 本発明の効果を、以下の実施例および比較例を用いて説明する。ただし、本発明 の技術的範囲が以下の実施例のみに制限されるわけではない。  The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples.
[0090] <実施例 1 >  <Example 1>
く正極の作製 >  Preparation of positive electrode>
正極活物質であるスピネル型マンガン酸リチウム（平均粒子径： 0. Ί μ χη) (80質量 %)、導電助剤であるアセチレンブラック（10質量0 /0)、およびバインダであるポリフッ 化ビニリデン (PVdF) (10質量％)からなる固形分に対し、スラリー粘度調整溶媒で ある N—メチル—2—ピロリドン (NMP)を適量添加して、正極活物質スラリーを調製 した。 As a cathode active material spinel-type lithium manganate (average particle size: 0. Ί μ χη) (80 wt%), acetylene black as a conductive aid (10 mass 0/0), and polyvinylidene fluoride ( A suitable amount of N-methyl-2-pyrrolidone (NMP), which is a slurry viscosity adjusting solvent, was added to the solid content of PVdF) (10% by mass) to prepare a positive electrode active material slurry.
[0091] 上記で調製した正極活物質スラリーを、正極集電体としてのアルミニウム箔 (厚さ： 2 O /z m)上に自走型ダイコータを用いて目付け量 12. 0mgZcm2、膜厚 46 /z m塗布 し、乾燥させて、積層体を得た。次いで、得られた積層体を、正極活物質層の空隙率 が 32%となるように、プレス機を用いてプレスし、集電体にタブを接続して、試験用正 極を作製した。 [0091] Using the self-propelled die coater, the positive electrode active material slurry prepared above was placed on an aluminum foil (thickness: 2 O / zm) as a positive electrode current collector, with a basis weight of 12.0 mgZcm 2 , a film thickness of 46 / zm was applied and dried to obtain a laminate. Next, the obtained laminate was pressed using a press so that the porosity of the positive electrode active material layer was 32%, and a tab was connected to the current collector to produce a test positive electrode.
[0092] <負極の作製 >  [0092] <Production of negative electrode>
負極活物質であるハードカーボン (平均粒子径： 10 m) (90質量％)、およびバイ ンダであるポリフッ化ピ-リデン (PVdF) (10質量0 /0)からなる固形分に対し、スラリー 粘度調整溶媒である N—メチル—2—ピロリドン (NMP)を適量添加して、負極活物 質スラリーを調製した。 Hard carbon as a negative electrode active material (average particle diameter: 10 m) (90 mass%), and by Sunda a is polyvinylidene Kapi - isopropylidene (PVdF) to (10 mass 0/0) solids consisting slurry viscosity An appropriate amount of N-methyl-2-pyrrolidone (NMP) as a adjusting solvent was added to prepare a negative electrode active material slurry.
[0093] 上記で調製した負極活物質スラリーを、負極集電体としての銅箔 (厚さ： 10 m)上 に自走型ダイコータを用いて目付け量 3mg/cm2、膜厚 30 μ m塗布し、乾燥させて 、積層体を得た。次いで、得られた積層体を、負極活物質層の空隙率が 55%となる ように、プレス機を用いてプレスし、集電体にタブを接続して、試験用負極を作製した [0094] <電解液の調製 > [0093] The negative electrode active material slurry prepared above was applied to a copper foil (thickness: 10 m) as a negative electrode current collector using a self-propelled die coater and a basis weight of 3 mg / cm 2 and a film thickness of 30 μm. And dried to obtain a laminate. Next, the obtained laminate was pressed using a press so that the porosity of the negative electrode active material layer was 55%, and a tab was connected to the current collector to prepare a test negative electrode. [0094] <Preparation of electrolyte solution>
エチレンカーボネート (EC)、およびジェチルカーボネート（DEC)を 1： 1の体積比 で混合し、電解液の可塑剤 (有機溶媒)とした。次いで、この可塑剤に、リチウム塩で ある LiPFを 1Mの濃度になるように添加して、電解液を調製した。  Ethylene carbonate (EC) and jetyl carbonate (DEC) were mixed at a volume ratio of 1: 1 to obtain a plasticizer (organic solvent) for the electrolytic solution. Next, LiPF, which is a lithium salt, was added to the plasticizer so as to have a concentration of 1M to prepare an electrolytic solution.
6  6
[0095] <ラミネート電池の作製 >  [0095] <Production of laminated battery>
上記で作製した試験用正極および試験用負極で、リチウムイオン電池用セパレー タであるポリエチレン製多孔膜 (厚さ： 25 m)を挟持した。次 、で得られた挟持体を 三方シール済みの外装材であるアルミラミネートバック中に挿入した。その後、前記 アルミネートバック中に上記で調製した電解液を注入し、ノ ッタカもタブが露出するよ うにパックを真空シールして、ラミネート電池を完成させた。  A polyethylene porous membrane (thickness: 25 m) as a separator for a lithium ion battery was sandwiched between the test positive electrode and the test negative electrode produced above. Next, the sandwiched body obtained in (1) was inserted into an aluminum laminate bag, which was a three-side sealed exterior material. Thereafter, the electrolyte prepared above was injected into the aluminate bag, and the pack was vacuum-sealed so that the tabs were also exposed to complete the laminated battery.
[0096] <実施例 2> <Example 2>
前記正極活物質スラリーの膜厚を 49 mとし、正極活物質層の空隙率が 35%とな るようにプレスしたこと以外は、上記の実施例 1と同様の手法により、ラミネート電池を 作製した。  A laminated battery was produced in the same manner as in Example 1 except that the thickness of the positive electrode active material slurry was 49 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 35%. .
[0097] <実施例 3 > <Example 3>
前記正極活物質スラリーの膜厚を 52 mとし、正極活物質層の空隙率が 39%とな るようにプレスしたこと以外は、上記の実施例 1と同様の手法により、ラミネート電池を 作製した。  A laminated battery was produced in the same manner as in Example 1 except that the thickness of the positive electrode active material slurry was 52 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 39%. .
[0098] <実施例 4> <Example 4>
前記正極活物質スラリーの膜厚を 58 mとし、正極活物質層の空隙率が 45%とな るようにプレスしたこと以外は、上記の実施例 1と同様の手法により、ラミネート電池を 作製した。  A laminated battery was produced in the same manner as in Example 1 except that the thickness of the positive electrode active material slurry was 58 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 45%. .
[0099] <実施例 5 > <Example 5>
前記正極活物質スラリーの膜厚を 61 μ mとし、正極活物質層の空隙率が 48%とな るようにプレスしたこと以外は、上記の実施例 1と同様の手法により、ラミネート電池を 作製した。  A laminated battery was produced in the same manner as in Example 1 except that the thickness of the positive electrode active material slurry was 61 μm and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 48%. did.
[0100] <実施例 6 > [0100] <Example 6>
前記正極活物質スラリーの固形分であるスピネル型マンガン酸リチウムの平均粒子 径を 5 μ mとし、正極活物質スラリーの膜厚を 47 μ mとしたこと以外は、上記の実施 例 1と同様の手法により、ラミネート電池を作製した。 Average particle of spinel type lithium manganate which is solid content of the positive electrode active material slurry A laminated battery was produced in the same manner as in Example 1 except that the diameter was 5 μm and the thickness of the positive electrode active material slurry was 47 μm.
[0101] <実施例 7> [0101] <Example 7>
前記正極活物質スラリーの膜厚を 52 mとし、正極活物質層の空隙率が 39%とな るようにプレスしたこと以外は、上記の実施例 6と同様の手法により、ラミネート電池を 作製した。  A laminated battery was produced in the same manner as in Example 6 except that the thickness of the positive electrode active material slurry was 52 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 39%. .
[0102] <実施例 8 > [0102] <Example 8>
前記正極活物質スラリーの膜厚を 58 mとし、正極活物質層の空隙率が 45%とな るようにプレスしたこと以外は、上記の実施例 6と同様の手法により、ラミネート電池を 作製した。  A laminated battery was produced in the same manner as in Example 6 except that the thickness of the positive electrode active material slurry was 58 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 45%. .
[0103] <実施例 9 > <Example 9>
前記正極活物質スラリー中の固形分であるスピネル型マンガン酸リチウム、ァセチ レンブラックおよび PVdFの質量比を 70： 20： 10とし、正極活物質スラリーの目付け 量および膜厚をそれぞれ 13. 7mgZcm2および 56 mとしたこと以外は、上記の実 施例 1と同様の手法により、ラミネート電池を作製した。 The mass ratio of spinel type lithium manganate, acetylene black, and PVdF, which are solids in the positive electrode active material slurry, is 70:20:10, and the basis weight and film thickness of the positive electrode active material slurry are 13.7 mgZcm 2 and A laminated battery was produced in the same manner as in Example 1 except that the length was 56 m.
[0104] <実施例 10 > <Example 10>
前記正極活物質スラリーの膜厚を 59 mとし、正極活物質層の空隙率が 35%とな るようにプレスしたこと以外は、上記の実施例 9と同様の手法により、ラミネート電池を 作製した。  A laminated battery was produced in the same manner as in Example 9 except that the thickness of the positive electrode active material slurry was 59 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 35%. .
[0105] <実施例 11 > <Example 11>
前記正極活物質スラリーの膜厚を 63 mとし、正極活物質層の空隙率が 39%とな るようにプレスしたこと以外は、上記の実施例 9と同様の手法により、ラミネート電池を 作製した。  A laminated battery was produced in the same manner as in Example 9 except that the thickness of the positive electrode active material slurry was 63 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 39%. .
[0106] <実施例 12 > <Example 12>
前記正極活物質スラリーの膜厚を 74 mとし、正極活物質層の空隙率が 45%とな るようにプレスしたこと以外は、上記の実施例 9と同様の手法により、ラミネート電池を 作製した。  A laminated battery was produced in the same manner as in Example 9 except that the thickness of the positive electrode active material slurry was 74 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 45%. .
[0107] <実施例 13 > 前記正極活物質スラリーの膜厚を 85 mとし、正極活物質層の空隙率が 55%とな るようにプレスしたこと以外は、上記の実施例 9と同様の手法により、ラミネート電池を 作製した。 <Example 13> A laminated battery was produced in the same manner as in Example 9 except that the thickness of the positive electrode active material slurry was 85 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 55%. .
[0108] <比較例 1 > [0108] <Comparative Example 1>
前記正極活物質スラリーの固形分であるスピネル型マンガン酸リチウムの平均粒子 径を 10 mとし、正極活物質スラリーの膜厚を 47 mとしたこと以外は、上記の実施 例 1と同様の手法により、ラミネート電池を作製した。  Except that the average particle diameter of spinel type lithium manganate, which is the solid content of the positive electrode active material slurry, was 10 m, and the film thickness of the positive electrode active material slurry was 47 m, the same method as in Example 1 above was used. A laminated battery was produced.
[0109] <比較例 2> [0109] <Comparative Example 2>
前記正極活物質スラリーの膜厚を 49 mとし、正極活物質層の空隙率が 35%とな るようにプレスしたこと以外は、上記の比較例 1と同様の手法により、ラミネート電池を 作製した。  A laminated battery was produced in the same manner as in Comparative Example 1 except that the thickness of the positive electrode active material slurry was 49 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 35%. .
[0110] <比較例 3 > [0110] <Comparative Example 3>
前記正極活物質スラリーの膜厚を 52 mとし、正極活物質層の空隙率が 39%とな るようにプレスしたこと以外は、上記の比較例 1と同様の手法により、ラミネート電池を 作製した。  A laminated battery was produced in the same manner as in Comparative Example 1 except that the thickness of the positive electrode active material slurry was 52 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 39%. .
[0111] <比較例 4> [0111] <Comparative Example 4>
前記正極活物質スラリーの膜厚を 60 mとし、正極活物質層の空隙率が 45%とな るようにプレスしたこと以外は、上記の比較例 1と同様の手法により、ラミネート電池を 作製した。  A laminated battery was produced in the same manner as in Comparative Example 1 except that the thickness of the positive electrode active material slurry was 60 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 45%. .
[0112] <比較例 5 > [0112] <Comparative Example 5>
前記正極活物質スラリーの膜厚を 61 μ mとし、正極活物質層の空隙率が 48%とな るようにプレスしたこと以外は、上記の比較例 1と同様の手法により、ラミネート電池を 作製した。  A laminated battery was produced in the same manner as in Comparative Example 1 except that the thickness of the positive electrode active material slurry was 61 μm and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 48%. did.
[0113] <比較例 6 > [0113] <Comparative Example 6>
前記正極活物質スラリーの固形分であるスピネル型マンガン酸リチウムの平均粒子 径を 7 mとし、正極活物質スラリーの膜厚を 47 mとしたこと以外は、上記の実施 例 1と同様の手法により、ラミネート電池を作製した。  Except that the average particle diameter of spinel type lithium manganate, which is the solid content of the positive electrode active material slurry, was 7 m, and the film thickness of the positive electrode active material slurry was 47 m, the same method as in Example 1 above was used. A laminated battery was produced.
[0114] <比較例 7> 前記正極活物質スラリーの膜厚を 52 mとし、正極活物質層の空隙率が 39%とな るようにプレスしたこと以外は、上記の比較例 6と同様の手法により、ラミネート電池を 作製した。 [0114] <Comparative Example 7> A laminated battery was produced in the same manner as in Comparative Example 6 except that the thickness of the positive electrode active material slurry was 52 m and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 39%. .
[0115] <比較例 8> [0115] <Comparative Example 8>
前記正極活物質スラリーの膜厚を 61 μ mとし、正極活物質層の空隙率が 48%とな るようにプレスしたこと以外は、上記の比較例 6と同様の手法により、ラミネート電池を 作製した。  A laminated battery was produced in the same manner as in Comparative Example 6 except that the thickness of the positive electrode active material slurry was 61 μm and the positive electrode active material layer was pressed so that the porosity of the positive electrode active material layer was 48%. did.
[0116] <ラミネート電池の電池特性の評価 >  [0116] <Evaluation of battery characteristics of laminated battery>
上記の各実施例および各比較例で作製したラミネート電池を用いて、以下の手法 により充放電試験を行い、出力特性の評価を行った。  Using the laminate batteries prepared in each of the above examples and comparative examples, a charge / discharge test was performed by the following method to evaluate the output characteristics.
[0117] 具体的には、各ラミネート電池について、 0. 2Cの定電流にて初充電を行い、 0. 5 Cの定電流にて放電後、 1Cの定電流にて 10サイクルの充放電試験を行った。  [0117] Specifically, each laminate battery was initially charged at a constant current of 0.2 C, discharged at a constant current of 0.5 C, and then charged and discharged at 10 cycles at a constant current of 1 C. Went.
[0118] その後、満充電状態 (4. 2V)で 100C (20mAZcm2以上）の定電流放電時の拡 散抵抗を評価し、拡散抵抗の逆数を算出した。そして、比較例 1のラミネート電池から 算出された逆数値を 1として、各実施例および各比較例のラミネート電池の比較例 1 のラミネート電池に対する相対出力値を算出した。結果を図 7及び図 8に示す。 [0118] Thereafter, the diffusion resistance during constant current discharge at 100 C (20 mAZcm 2 or more) in a fully charged state (4.2 V) was evaluated, and the reciprocal of the diffusion resistance was calculated. Then, assuming that the reciprocal value calculated from the laminated battery of Comparative Example 1 was 1, the relative output value of the laminated battery of each Example and each Comparative Example with respect to the laminated battery of Comparative Example 1 was calculated. The results are shown in FIGS.
[0119] <正極活物質層の空隙率の増大によって生じる効果 >  [0119] <Effect caused by increase in porosity of positive electrode active material layer>
上記の比較例から示されるように、正極活物質の平均粒子径が 10 m程度と大き いと、正極活物質層の空隙率が増大しても、正極活物質層における拡散抵抗はほと んど影響を受けず、相対出力は変化しない。これに対し、実施例から示されるように、 正極活物質の平均粒子径が極めて小さいと、正極活物質層の空隙率の増大に対応 して、正極活物質層における拡散抵抗が低下し、相対出力が増加する。従って、電 極活物質の小粒径ィ匕と電極活物質の空隙率の増大とを組み合わせることによって、 100Cという高出力条件下においても優れた出力特性を発揮しうる電池が提供されう ることが示唆される。  As shown in the comparative example above, when the average particle diameter of the positive electrode active material is as large as about 10 m, even if the porosity of the positive electrode active material layer increases, the diffusion resistance in the positive electrode active material layer is almost the same. Unaffected and relative output does not change. On the other hand, as shown in the examples, when the average particle diameter of the positive electrode active material is extremely small, the diffusion resistance in the positive electrode active material layer decreases corresponding to the increase in the porosity of the positive electrode active material layer, and the relative Output increases. Therefore, by combining the small particle size of the electrode active material and the increase in the porosity of the electrode active material, a battery capable of exhibiting excellent output characteristics even under a high output condition of 100 C can be provided. Is suggested.
[0120] <導電助剤の添加量の増大によって生じる効果 >  [0120] <Effects caused by increased amount of conductive additive>
実施例 1〜5と実施例 9〜13の比較から、導電助剤の添加量を増やすことにより、 電極活物質層の空隙率が等しい場合であっても、拡散抵抗がより一層低下し、相対 出力が増加しうることがわかる。なお、この効果は、電極活物質層の空隙率が増大す るにつれて顕著に発現する。 From the comparison of Examples 1 to 5 and Examples 9 to 13, by increasing the addition amount of the conductive auxiliary agent, even when the porosity of the electrode active material layer is equal, the diffusion resistance is further reduced, It can be seen that the output can increase. Note that this effect becomes more prominent as the porosity of the electrode active material layer increases.
[0121] 以上のことから、本発明の電池用電極は、電池の出力特性の向上に有効に寄与し うる。  [0121] From the above, the battery electrode of the present invention can contribute effectively to the improvement of the output characteristics of the battery.
産業上の利用可能性  Industrial applicability
[0122] 本発明によれば、高出力条件下での充放電時における電池の内部抵抗の増大が 抑制され、充分な電流を取り出しうるリチウムイオン二次電池が提供されうる。 [0122] According to the present invention, it is possible to provide a lithium ion secondary battery in which an increase in the internal resistance of the battery during charging and discharging under high output conditions is suppressed, and a sufficient current can be taken out.

Claims

請求の範囲 The scope of the claims
[1] 集電体と、前記集電体上に形成された、正極活物質を含む第 1の正極活物質層と を有する電池用電極であって、  [1] A battery electrode having a current collector and a first positive electrode active material layer containing a positive electrode active material formed on the current collector,
前記正極活物質の平均粒子径が 5 m以下であり、前記第 1の正極活物質層の空 隙率が 30%以上であることを特徴とする電池用電極。  The battery electrode, wherein the positive electrode active material has an average particle size of 5 m or less, and the porosity of the first positive electrode active material layer is 30% or more.
[2] 前記第 1の正極活物質層が、前記第 1の正極活物質層の全質量に対して 5質量％ 以上の導電助剤をさらに含む、請求項 1に記載の電池用電極。 [2] The battery electrode according to claim 1, wherein the first positive electrode active material layer further contains 5% by mass or more of a conductive additive with respect to the total mass of the first positive electrode active material layer.
[3] 前記正極活物質が、リチウム 遷移金属酸化物、リチウム 遷移金属リン酸化合物[3] The positive electrode active material is a lithium transition metal oxide or a lithium transition metal phosphate compound.
、およびリチウム 遷移金属硫酸ィ匕合物力 なる群力 選択される 1種または 2種以 上の材料を含む、請求項 1または 2に記載の電池用電極。 3. The battery electrode according to claim 1, comprising one or more materials selected from the group force of lithium transition metal sulfate compound compound force.
[4] 前記集電体と前記第 1の正極活物質層との間に、前記第 1の正極活物質層よりも空 隙率の小さい第 2の正極活物質層が介在する、請求項 1〜3のいずれ力 1項に記載 の電池用電極。 [4] The second cathode active material layer having a lower porosity than the first cathode active material layer is interposed between the current collector and the first cathode active material layer. The electrode for a battery according to any one of ~ 3.
[5] 集電体と、前記集電体上に形成された、正極活物質を含む第 1の負極活物質層と を有する電池用電極であって、  [5] A battery electrode having a current collector and a first negative electrode active material layer containing a positive electrode active material formed on the current collector,
前記負極活物質の平均粒子径が 10 m以下であり、前記第 1の負極活物質層の 空隙率が 50%以上であることを特徴とする電池用電極。  The battery electrode, wherein the negative electrode active material has an average particle size of 10 m or less, and the porosity of the first negative electrode active material layer is 50% or more.
[6] 前記負極活物質層が、前記負極活物質層の全質量に対して 1質量％以上の導電 助剤をさらに含む、請求項 5に記載の電池用電極。 [6] The battery electrode according to claim 5, wherein the negative electrode active material layer further contains 1% by mass or more of a conductive additive with respect to the total mass of the negative electrode active material layer.
[7] 前記負極活物質が、炭素材料、リチウム 遷移金属酸化物、金属材料、およびリチ ゥム—金属合金材料力 なる群力 選択される 1種または 2種以上の材料を含む、請 求項 5または 6に記載の電池用電極。 [7] The claim, wherein the negative electrode active material includes one or more materials selected from a carbon material, a lithium transition metal oxide, a metal material, and a lithium-metal alloy material force. The battery electrode according to 5 or 6.
[8] 前記集電体と前記第 1の負極活物質層との間に、前記第 1の負極活物質層よりも空 隙率の小さい第 2の負極活物質層が介在する、請求項 5〜7のいずれ力 1項に記載 の電池用電極。 [8] The second negative electrode active material layer having a lower porosity than the first negative electrode active material layer is interposed between the current collector and the first negative electrode active material layer. The electrode for a battery according to any one of? 7.
[9] 前記導電助剤が炭素材料である、請求項 2または 6に記載の電池用電極。  [9] The battery electrode according to claim 2 or 6, wherein the conductive additive is a carbon material.
[10] 正極、電解質層、および負極がこの順に積層されてなる少なくとも 1つの単電池層 を含むリチウムイオン電池であって、 前記正極または前記負極の少なくとも一方力 請求項 1〜9のいずれ力 1項に記載 の電池用電極である、リチウムイオン二次電池。 [10] A lithium ion battery comprising at least one unit cell layer in which a positive electrode, an electrolyte layer, and a negative electrode are laminated in this order, The lithium ion secondary battery which is an electrode for a battery according to any one of claims 1 to 9, wherein at least one force of the positive electrode or the negative electrode.
[11] 前記電解質層が、液体電解質、ゲル電解質、または真性ポリマー電解質を含む、 請求項 10に記載のリチウムイオン二次電池。 11. The lithium ion secondary battery according to claim 10, wherein the electrolyte layer includes a liquid electrolyte, a gel electrolyte, or an intrinsic polymer electrolyte.
[12] ノ ィポーラ型リチウムイオン二次電池である、請求項 10または 11に記載のリチウム イオン二次電池。 12. The lithium ion secondary battery according to claim 10 or 11, wherein the lithium ion secondary battery is a nopolar type lithium ion secondary battery.
[13] 請求項 10〜12のいずれか 1項に記載のリチウムイオン二次電池を用いた組電池。  [13] An assembled battery using the lithium ion secondary battery according to any one of claims 10 to 12.
[14] 請求項 10〜12のいずれか 1項に記載のリチウムイオン二次電池、または請求項 13 に記載の組電池をモータ駆動用電源として搭載した車両。 [14] A vehicle on which the lithium ion secondary battery according to any one of claims 10 to 12 or the assembled battery according to claim 13 is mounted as a motor driving power source.
[15] 溶媒に活物質を添加することにより、活物質を含む活物質スラリーを調整する活物 質スラリー調整工程と、 [15] An active material slurry adjustment step of adjusting an active material slurry containing an active material by adding the active material to a solvent;
集電体の表面に活物質スラリーを塗布し、乾燥させることにより塗膜を形成する塗 膜形成工程と、  A coating film forming step in which an active material slurry is applied to the surface of the current collector and dried to form a coating film; and
塗膜形成工程を経て作製された積層体を積層方向にプレスするプレス工程とを有 し、  And a pressing process for pressing the laminate produced through the coating film forming process in the laminating direction,
塗膜形成工程と、プレス工程との組み合わせ工程を 2回以上繰り返すことを特徴と する、電池用電極の製造方法。  A method for producing an electrode for a battery, characterized in that a combination process of a coating film forming process and a pressing process is repeated twice or more.
[16] 前記組み合わせ工程において、 n+ 1回目（n≥ 1)のプレス工程におけるプレス圧 力が n回目のプレス工程におけるプレス圧力よりも小さい、請求項 15に記載の製造 方法。 16. The manufacturing method according to claim 15, wherein, in the combination step, the press pressure in the n + 1 first press step (n≥1) is smaller than the press pressure in the nth press step.
[17] 前記塗膜形成工程における前記活物質スラリーの塗布が、インクジェット方式を用 いて行われる、請求項 15または請求項 16に記載の製造方法。  [17] The production method according to claim 15 or 16, wherein the application of the active material slurry in the coating film forming step is performed using an inkjet method.
PCT/JP2006/318114 2005-09-14 2006-09-13 Battery-use electrode WO2007032365A1 (en)

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