JP2021034141A - Lithium ion battery module and battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To connect a current collector on the outermost layer of a power storage element and a portion for extracting a current to the outside without causing poor contact even if the power storage element is distorted or the thickness of an electrode is uneven. To provide a battery module. A lithium ion battery module having a first metal sheet, a power storage element, and a second metal sheet in this order, wherein the power storage element is a positive electrode current collector, a positive electrode active material layer, a separator, and the like. The negative electrode active material layer and the negative electrode current collector are laminated in this order, the positive electrode current collector and the negative electrode current collector are provided on the outermost layer, and the outer periphery of the positive electrode active material layer and the negative electrode active material layer is sealed. This includes a lithium-ion cell in which an electrolytic solution is sealed, and is located between the positive electrode current collector in the outermost layer of the power storage element and the first metal sheet, and / or the power storage element. It has a conductive elastic member arranged between the negative electrode current collector of the outermost layer and the second metal sheet, and the first metal sheet and the second metal sheet are insulated from each other. A lithium-ion battery module characterized by being [Selection diagram] Fig. 2

Description

The present invention relates to a lithium ion battery module and a battery pack.

A lithium ion battery having a high energy density is known as a battery that can be used as a power source for electric vehicles and hybrid electric vehicles. Then, the lithium ion battery is made into a battery module in which a power storage element in which a single battery is connected in series is housed in a battery outer container and adjusted to a required voltage, or a battery pack in which a plurality of battery modules are combined to adjust the voltage and capacity. Used as a power source.

Among them, there is known a laminated battery in which a plurality of stacked bipolar batteries that can be connected by taking out a current to the outside without pulling out an electrode terminal from the package are sealed in a laminated sheet (Patent Document 1).

Japanese Unexamined Patent Publication No. 2005-276486

The laminated battery (also referred to as a battery module) described in Patent Document 1 draws current to the outside by a contact portion between a current collector on the outermost layer of the power storage element and a conductive layer of the laminated sheet, but in the manufacturing process. Due to the resulting distortion of the power storage element and uneven thickness of the electrodes, poor contact may occur between the current collector on the outermost layer and the metal layer of the battery outer container, or the surface of the metal layer may be smooth. It was not sufficient, and poor contact between the battery modules sometimes occurred when the battery modules were stacked and connected to each other.

The present invention has been made in view of the above problems, and even if the power storage element is distorted or the thickness of the electrodes is uneven, the current is applied to the current collector on the outermost layer of the power storage element and to the outside without causing poor contact. It is an object of the present invention to provide a lithium ion battery module that can be connected to a portion for taking out a current.

The present invention is a lithium ion battery module having a first metal sheet, a power storage element, and a second metal sheet in this order, wherein the power storage element is a positive electrode current collector, a positive electrode active material layer, a separator, and the like. The negative electrode active material layer and the negative electrode current collector are laminated in this order, the positive electrode current collector and the negative electrode current collector are provided as the outermost layer, and the outer periphery of the positive electrode active material layer and the negative electrode active material layer is sealed. This includes a lithium-ion cell in which an electrolytic solution is sealed, and is located between the positive electrode current collector in the outermost layer of the power storage element and the first metal sheet, and / or the power storage element. It has a conductive elastic member arranged between the negative electrode current collector of the outermost layer and the second metal sheet, and the first metal sheet and the second metal sheet are insulated from each other. A plurality of lithium ion battery modules, a battery pack including a plurality of the lithium ion battery modules, and a positive electrode and a negative electrode of the lithium ion battery module connected in series, and a plurality of the lithium ion battery modules. It is a battery pack including the positive electrode and the negative electrode of the lithium ion battery module connected in parallel.

In the lithium ion battery module of the present invention, even if the power storage element is distorted or the thickness of the electrode is uneven, the current collector on the outermost layer of the power storage element and the portion that draws current to the outside are connected without causing contact failure. can do.

FIG. 1 is a cross-sectional view schematically showing an example of a lithium ion cell. FIG. 2A is a cross-sectional view schematically showing an example of the first aspect of the lithium ion battery module, and FIG. 2B schematically shows an example of the first aspect of the lithium ion battery module. It is a perspective sectional view which shows. FIG. 3A is a cross-sectional view schematically showing an example of the second aspect of the lithium ion battery module, and FIG. 3B schematically shows an example of the second aspect of the lithium ion battery module. It is a perspective sectional view which shows. FIG. 4 is a cross-sectional view schematically showing an example of the first aspect of the battery pack. FIG. 5 is a cross-sectional view schematically showing an example of the second aspect of the battery pack.

Hereinafter, the lithium ion battery module of the present invention will be described.
The module means a combination unit that is combined so as to function as one power source by connecting a plurality of cells in series.

The lithium ion battery module of the present invention is a lithium ion battery module having a first metal sheet, a power storage element, and a second metal sheet in this order, and the power storage element is a positive electrode current collector and a positive electrode activity. The material layer, the separator, the negative electrode active material layer, and the negative electrode current collector are laminated in this order, and the positive electrode current collector and the negative electrode current collector are provided as the outermost layer, and the positive electrode active material layer and the negative electrode active material layer are provided. It contains a lithium ion cell cell in which an electrolytic solution is sealed by sealing the outer periphery of the storage element, and between the positive electrode current collector in the outermost layer of the power storage element and the first metal sheet, and / Alternatively, it has a conductive elastic member arranged between the negative electrode current collector in the outermost layer of the power storage element and the second metal sheet, and has the first metal sheet and the second metal sheet. It is characterized in that and are insulated from each other.
First, a lithium ion cell will be described.

[Lithium-ion cell]
In the lithium ion cell, the positive electrode current collector, the positive electrode active material layer, the separator, the negative electrode active material layer and the negative electrode current collector are laminated in this order, and the positive electrode current collector and the negative electrode current collector are provided in the outermost layer. Then, the electrolytic solution is sealed by sealing the outer periphery of the positive electrode active material layer and the negative electrode active material layer.

FIG. 1 is a cross-sectional view schematically showing an example of a lithium ion cell.
In the lithium ion cell 100 shown in FIG. 1, the positive electrode current collector 11, the positive electrode active material layer 13, the separator 30, the negative electrode active material layer 23, and the negative electrode current collector 21 are laminated in this order, and the positive electrode current collector 11 And the negative electrode current collector 21 are provided in the outermost layer. The outer periphery of the positive electrode active material layer 13 and the negative electrode active material layer 23 is sealed with a sealing material 40, and has a structure in which an electrolytic solution is sealed.
Hereinafter, each configuration of the lithium ion cell will be described.

(Positive current collector)
As the positive electrode current collector 11, a current collector used in a known lithium ion cell can be used. For example, a known metal current collector and a resin current collector composed of a conductive material and a resin (specially The resin current collectors and the like described in Kai 2012-150905 and International Publication No. 2015-005116, etc.) can be used.
The positive electrode current collector 11 is preferably a resin current collector from the viewpoint of battery characteristics and the like.

Examples of the metal collector include copper, aluminum, titanium, nickel, tantalum, niobium, hafnium, zirconium, zinc, tungsten, bismuth, antimony, alloys containing one or more of these metals, and a group consisting of stainless alloys. One or more metallic materials selected from are mentioned. These metal materials may be used in the form of a thin plate, a metal foil, or the like. Further, a metal current collector in which the metal material is formed on the surface of a base material made of a material other than the metal material by a method such as sputtering, electrodeposition, or coating may be used.

The resin current collector preferably contains a conductive filler and a matrix resin.
Examples of the matrix resin include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polycycloolefin (PCO), polyethylene terephthalate (PET), polyether nitrile (PEN), and polytetrafluoroethylene (PTFE). ), Styrene butadiene rubber (SBR), polyacrylic nitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVdF), epoxy resin, silicone resin, or a mixture thereof.
From the viewpoint of electrical stability, polyethylene (PE), polypropylene (PP), polymethylpentene (PMP) and polycycloolefin (PCO) are preferable, and polyethylene (PE), polypropylene (PP) and polymethylpentene are more preferable. (PMP).

The conductive filler is selected from materials having conductivity.
Specifically, metals [nickel, aluminum, stainless steel (SUS), silver, copper, titanium, etc.], carbon [graphite and carbon black (acetylene black, ketjen black, furnace black, channel black, thermal lamp black, etc.), etc.), etc. ], And a mixture thereof, etc., but is not limited to these.
These conductive fillers may be used alone or in combination of two or more. Moreover, you may use these alloys or metal oxides. From the viewpoint of electrical stability, aluminum, stainless steel, carbon, silver, copper, titanium and mixtures thereof are preferable, silver, aluminum, stainless steel and carbon are more preferable, and carbon is even more preferable. Further, as these conductive fillers, a conductive material (a metal one among the above-mentioned conductive filler materials) may be coated around a particle-based ceramic material or a resin material by plating or the like.

The average particle size of the conductive filler is not particularly limited, but is preferably 0.01 to 10 μm, more preferably 0.02 to 5 μm, and 0, from the viewpoint of the electrical characteristics of the battery. It is more preferably .03 to 1 μm. In addition, in this specification, "particle diameter" means the maximum distance L among the distances between arbitrary two points on the contour line of a particle. The value of the "average particle size" is the average value of the particle size of the particles observed in several to several tens of fields using an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM). The calculated value shall be adopted.

The shape (form) of the conductive filler is not limited to the particle form, and may be a form other than the particle form, and may be a form practically used as a so-called filler-based conductive resin composition such as carbon nanotubes. Good.

The conductive filler may be a conductive fiber whose shape is fibrous.
The conductive fibers include carbon fibers such as PAN-based carbon fibers and pitch-based carbon fibers, conductive fibers in which a metal having good conductivity and graphite are uniformly dispersed in synthetic fibers, and a metal such as stainless steel. Examples thereof include fibrous metal fibers, conductive fibers in which the surface of organic fibers is coated with metal, and conductive fibers in which the surface of organic fibers is coated with a resin containing a conductive substance. Among these conductive fibers, carbon fibers are preferable. Further, a polypropylene resin kneaded with graphene is also preferable.
When the conductive filler is a conductive fiber, its average fiber diameter is preferably 0.1 to 20 μm.

The weight ratio of the conductive filler in the resin current collector is preferably 5 to 90% by weight, more preferably 20 to 80% by weight.
In particular, when the conductive filler is carbon, the weight ratio of the conductive filler is preferably 20 to 30% by weight.

The resin current collector may contain other components (dispersant, cross-linking accelerator, cross-linking agent, colorant, ultraviolet absorber, plasticizer, etc.) in addition to the matrix resin and the conductive filler. Further, a plurality of resin current collectors may be laminated and used, or a resin current collector and a metal foil may be laminated and used.

The thickness of the positive electrode current collector 11 is not particularly limited, but is preferably 5 to 150 μm. When a plurality of resin current collectors are laminated and used as a positive electrode current collector, the total thickness after lamination is preferably 5 to 150 μm.

The positive electrode current collector 11 can be obtained, for example, by forming a conductive resin composition obtained by melt-kneading a matrix resin, a conductive filler, and a dispersant for a filler used if necessary into a film by a known method. it can.
Examples of the method for molding the conductive resin composition into a film include known film molding methods such as the T-die method, the inflation method, and the calender method. The positive electrode current collector 11 can also be obtained by a molding method other than film molding.

(Positive electrode active material layer)
The positive electrode active material layer 13 is preferably a non-bonded body of a mixture containing the positive electrode active material.
Here, in the non-binding body, the position of the positive electrode active material is not fixed in the positive electrode active material layer, and the positive electrode active materials and the positive electrode active materials and the positive electrode active material and the current collector are irreversibly. It means that it is not fixed.
When the positive electrode active material layer 13 is a non-binding body, since the positive electrode active materials are not irreversibly fixed to each other, the positive electrode active materials can be separated without mechanically destroying the interface between the positive electrode active materials, and the positive electrode active materials can be separated from each other. Even when stress is applied to the material layer 13, the movement of the positive electrode active material can prevent the positive electrode active material layer 13 from being destroyed, which is preferable.
The positive electrode active material layer 13 which is a non-binding body can be obtained by a method such as forming the positive electrode active material layer 13 into a positive electrode active material layer 13 containing a positive electrode active material and an electrolytic solution and not containing a binder. it can.
In the present specification, the binder means a drug that cannot reversibly fix the positive electrode active materials to each other and the positive electrode active material to the current collector, and starch, polyvinylidene fluoride, polyvinyl alcohol, and carboxy. Examples thereof include known solvent-drying type binders for lithium ion batteries such as methyl cellulose, polyvinylpyrrolidone, tetrafluoroethylene, styrene-butadiene rubber, polyethylene and polypropylene. These binders are used by dissolving or dispersing in a solvent, and by volatilizing and distilling off the solvent, the surface solidifies without showing adhesiveness. Cannot be fixed reversibly.

As the positive electrode active material, composite oxide of lithium and transition metal {composite oxide is a transition metal is one _{(LiCoO 2, LiNiO 2, LiAlMnO} 4, LiMnO 2 and LiMn ₂ O _4, etc.), transition metal elements Two types of composite oxides (eg LiFeMnO ₄ , LiNi _1-x Co _x O ₂ , LiMn _1-y Co _y O ₂ , LiNi _1/3 Co _1/3 Al _1/3 O ₂ and LiNi _0.8 Co _0.15 Al _0.05 O ₂₎ and a composite oxide metal element is three or more [e.g. _{LiM a M 'b M''} c O 2 (M, M' and M '' is different from the transition metal elements, respectively , and the meet a + b + c = 1. for example _{LiNi 1/3 Mn 1/3 Co 1/3 O 2} ) , etc.] or the like}, lithium-containing transition metal phosphate (e.g. LiFePO _4, LiCoPO _4, LiMnPO ₄ and LiNiPO ₄ ), Transition metal oxides (eg MnO ₂ and V ₂ O ₅ ), transition metal sulfides (eg MoS ₂ and TiS ₂ ) and conductive polymers (eg polyaniline, polypyrrole, polythiophene, polyacetylene and poly-p-phenylene and Polyvinylcarbazole) and the like, and two or more kinds may be used in combination.
The lithium-containing transition metal phosphate may be one in which a part of the transition metal site is replaced with another transition metal.

The volume average particle size of the positive electrode active material is preferably 0.01 to 100 μm, more preferably 0.1 to 35 μm, and even more preferably 2 to 30 μm from the viewpoint of the electrical characteristics of the battery. ..

The positive electrode active material may be a coated positive electrode active material in which at least a part of the surface thereof is coated with a coating material containing a polymer compound.
When the periphery of the positive electrode active material is coated with a coating material, the volume change of the positive electrode can be alleviated and the expansion of the positive electrode can be suppressed.

As the polymer compound constituting the coating material, those described as the active material coating resin in JP-A-2017-054703 and International Publication No. 2015-005117 can be preferably used.

The covering material may contain a conductive agent.
As the conductive agent, the same conductive filler as that contained in the positive electrode current collector 11 can be preferably used.

The positive electrode active material layer 13 may contain an adhesive resin.
Examples of the adhesive resin include those prepared by mixing a small amount of an organic solvent with the non-aqueous secondary battery active material coating resin described in JP-A-2017-054703 and adjusting the glass transition temperature to room temperature or lower. Further, those described as a pressure-sensitive adhesive in JP-A No. 10-255805 can be preferably used.
The adhesive resin is a resin having adhesiveness (property of adhering by applying a slight pressure without using water, solvent, heat, etc.) without solidifying even if the solvent component is volatilized and dried. Means. On the other hand, a solution-drying type electrode binder used as a binder means a binder that dries and solidifies by volatilizing a solvent component to firmly bond and fix active materials to each other.
Therefore, the above-mentioned binder (solution-drying type electrode binder) and the adhesive resin are different materials.

The positive electrode active material layer 13 may contain an electrolytic solution containing an electrolyte and a non-aqueous solvent.
As the electrolyte, those used in known electrolytes can be used, for example, lithium salts of inorganic acids such as _{LiPF 6} , LiBF ₄ , LiSbF ₆ , _{LiAsF 6} , LiN (FSO ₂ ) ₂ and LiClO _4. Lithium salts of organic acids such as LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ and LiC (CF ₃ SO ₂ ) ₃ can be mentioned, and LiN (FSO _{2 ) 2} (also referred to as LiFSI). ) Is preferable.

As the non-aqueous solvent, those used in known electrolytic solutions can be used, and for example, a lactone compound, a cyclic or chain carbonate, a chain carboxylic acid ester, a cyclic or chain ether, a phosphoric acid ester, or a nitrile can be used. Compounds, amide compounds, sulfones, sulfolanes and the like and mixtures thereof can be used.

Examples of the lactone compound include a 5-membered ring (γ-butyrolactone, γ-valerolactone, etc.) and a 6-membered ring lactone compound (δ-valerolactone, etc.).

Examples of the cyclic carbonic acid ester include propylene carbonate, ethylene carbonate and butylene carbonate.
Examples of the chain carbonate ester include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl-n-propyl carbonate, ethyl-n-propyl carbonate, di-n-propyl carbonate and the like.

Examples of the chain carboxylic acid ester include methyl acetate, ethyl acetate, propyl acetate, methyl propionate and the like.
Examples of the cyclic ether include tetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 1,4-dioxane and the like.
Examples of the chain ether include dimethoxymethane and 1,2-dimethoxyethane.

Phosphate esters include trimethyl phosphate, triethyl phosphate, ethyl dimethyl phosphate, diethyl methyl phosphate, tripropyl phosphate, tributyl phosphate, tri (trifluoromethyl) phosphate, tri (trichloromethyl) phosphate, Tri (trifluoroethyl) phosphate, tri (triperfluoroethyl) phosphate, 2-ethoxy-1,3,2-dioxaphosphoran-2-one, 2-trifluoroethoxy-1,3,2- Examples thereof include dioxaphosphoran-2-one and 2-methoxyethoxy-1,3,2-dioxaphosphoran-2-one.
Examples of the nitrile compound include acetonitrile and the like. Examples of the amide compound include DMF and the like. Examples of the sulfone include dimethyl sulfone and diethyl sulfone.
One type of non-aqueous solvent may be used alone, or two or more types may be used in combination.

Among the non-aqueous solvents, lactone compounds, cyclic carbonates, chain carbonates and phosphate esters are preferable from the viewpoint of battery output and charge / discharge cycle characteristics, and lactone compounds, cyclic carbonates and chains are more preferable. A carbonic acid ester is particularly preferable, and a mixed solution of a cyclic carbonic acid ester and a chain carbonic acid ester is particularly preferable. The most preferable is a mixed solution of ethylene carbonate (EC) and dimethyl carbonate (DMC), or a mixed solution of ethylene carbonate (EC) and propylene carbonate (PC).

The positive electrode active material layer 13 may contain a conductive auxiliary agent.
As the conductive auxiliary agent, a conductive material similar to the conductive filler contained in the positive electrode current collector 11 can be preferably used.

The weight ratio of the conductive auxiliary agent in the positive electrode active material layer 13 is preferably 3 to 10% by weight.

The positive electrode active material layer 13 can be produced, for example, by applying a slurry containing the positive electrode active material and the electrolytic solution to the surface of the positive electrode current collector 11 or the base material to remove excess electrolytic solution.
When the positive electrode active material layer 13 is formed on the surface of the base material, the positive electrode active material layer 13 may be combined with the positive electrode current collector 11 by a method such as transfer.
The slurry may contain a conductive auxiliary agent or an adhesive resin, if necessary. Further, the positive electrode active material may be a coated positive electrode active material.

The thickness of the positive electrode active material layer 13 is not particularly limited, but is preferably 150 to 600 μm, more preferably 200 to 450 μm from the viewpoint of battery performance.

(Negative electrode current collector)
As the negative electrode current collector 21, the same configuration as that described in the positive electrode current collector 11 can be appropriately selected and used, and can be obtained by the same method.
The negative electrode current collector 21 is preferably a resin current collector from the viewpoint of battery characteristics and the like.
The thickness of the negative electrode current collector 21 is not particularly limited, but is preferably 5 to 150 μm.

(Negative electrode active material layer)
The negative electrode active material layer 23 is preferably a non-bonded body of a mixture containing the negative electrode active material. The reason why the negative electrode active material layer is preferably a non-bonded body, and the reason why the positive electrode active material layer 13 is preferably a non-bound body in the method of obtaining the negative electrode active material layer 23 which is a non-bound body, etc. , And the method for obtaining the positive electrode active material layer 13 which is a non-bonded body.

Examples of the negative electrode active material include carbon-based materials [graphite, non-graphitizable carbon, amorphous carbon, calcined resin (for example, phenol resin, furan resin, etc. are calcined and carbonized), cokes (for example, pitch coke, needle). Coke and petroleum coke, etc.) and carbon fibers, etc.], silicon-based materials [silicon, silicon oxide (SiOx), silicon-carbon composite (carbon particles whose surface is coated with silicon and / or silicon carbide, silicon particles or oxidation) Silicon particles whose surface is coated with carbon and / or silicon carbide, silicon carbide, etc.) and silicon alloys (silicon-aluminum alloy, silicon-lithium alloy, silicon-nickel alloy, silicon-iron alloy, silicon-titanium alloy, silicon -Manganese alloys, silicon-copper alloys, silicon-tin alloys, etc.)], conductive polymers (eg, polyacetylene and polypyrrole, etc.), metals (tin, aluminum, zirconium, titanium, etc.), metal oxides (titanium oxide and titanium oxide, etc.) (Lithium-titanium oxide, etc.), metal alloys (for example, lithium-tin alloys, lithium-aluminum alloys, lithium-aluminum-manganese alloys, etc.) and the like, and mixtures of these with carbon-based materials and the like can be mentioned.
Among the above-mentioned negative electrode active materials, those which do not contain lithium or lithium ions inside may be pre-doped with a part or all of the negative electrode active materials containing lithium or lithium ions in advance.

Among these, carbon-based materials, silicon-based materials and mixtures thereof are preferable from the viewpoint of battery capacity and the like, graphite, graphitizable carbon and amorphous carbon are more preferable as carbon-based materials, and silicon-based materials are more preferable. , Silicon oxide and silicon-carbon composites are more preferred.

The volume average particle size of the negative electrode active material is preferably 0.01 to 100 μm, more preferably 0.1 to 20 μm, and even more preferably 2 to 10 μm from the viewpoint of the electrical characteristics of the battery.

In the present specification, the volume average particle size of the negative electrode active material means the particle size (Dv50) at an integrated value of 50% in the particle size distribution obtained by the microtrack method (laser diffraction / scattering method). The microtrack method is a method for obtaining a particle size distribution using scattered light obtained by irradiating particles with laser light. A microtrack or the like manufactured by Nikkiso Co., Ltd. can be used for measuring the volume average particle size.

The negative electrode active material may be a coated negative electrode active material in which at least a part of the surface thereof is coated with a coating material containing a polymer compound.
When the periphery of the negative electrode active material is coated with a coating material, the volume change of the negative electrode can be alleviated and the expansion of the negative electrode can be suppressed.

As the coating material, the same material as the coating material constituting the coated positive electrode active material can be preferably used.

The negative electrode active material layer 23 contains an electrolytic solution containing an electrolyte and a non-aqueous solvent.
As the composition of the electrolytic solution, an electrolytic solution similar to the electrolytic solution contained in the positive electrode active material layer 13 can be preferably used.

The negative electrode active material layer 23 may contain a conductive auxiliary agent.
As the conductive auxiliary agent, a conductive material similar to the conductive filler contained in the positive electrode active material layer 13 can be preferably used.

The weight ratio of the conductive auxiliary agent in the negative electrode active material layer 23 is preferably 2 to 10% by weight.

The negative electrode active material layer 23 may contain an adhesive resin.
As the adhesive resin, the same adhesive resin as the adhesive resin which is an optional component of the positive electrode active material layer 13 can be preferably used.

The negative electrode active material layer 23 can be produced, for example, by applying a slurry containing the negative electrode active material and the electrolytic solution to the surface of the negative electrode current collector 21 or the base material to remove excess electrolytic solution.
When the negative electrode active material layer 23 is formed on the surface of the base material, the negative electrode active material layer 23 may be combined with the negative electrode current collector 21 by a method such as transfer.
The slurry may contain a conductive auxiliary agent, an adhesive resin, or the like, if necessary. Further, the negative electrode active material may be a coated negative electrode active material.

The thickness of the negative electrode active material layer 23 is not particularly limited, but is preferably 150 to 600 μm, more preferably 200 to 450 μm from the viewpoint of battery performance.

(Separator)
The separator 30 includes a porous film made of polyethylene or polypropylene, a laminated film of the above-mentioned porous film (laminated film of porous polyethylene film and porous polypropylene, etc.), synthetic fiber (polyester fiber, aramid fiber, etc.) or glass fiber. Examples thereof include non-woven films made of polypropylene, and separators used in known lithium-ion single cells such as those in which ceramic fine particles such as silica, alumina, and titania are adhered to their surfaces.

(Lithium-ion cell)
The lithium ion cell 100 has a configuration in which an electrolytic solution is sealed by sealing the outer periphery of the positive electrode active material layer 13 and the negative electrode active material layer 23.
Examples of the method of sealing the outer periphery of the positive electrode active material layer 13 and the negative electrode active material layer 23 include a method of sealing using a sealing material 40.
The sealing material 40 is arranged between the positive electrode current collector 11 and the negative electrode current collector 21, and has a function of sealing the outer periphery of the separator 30.

The sealing material 40 is not particularly limited as long as it is a material durable to the electrolytic solution, but a polymer material is preferable, and a thermosetting polymer material is more preferable.
Specific examples thereof include epoxy-based resins, polyolefin-based resins, polyurethane-based resins, polyvinylidene fluoride resins, and the like, and epoxy-based resins are preferable because they have high durability and are easy to handle.

As a method for manufacturing the lithium ion cell 100, for example, a positive electrode current collector 11, a positive electrode active material layer 13, a separator 30, a negative electrode active material layer 23, and a negative electrode current collector 21 are superposed in this order, and then an electrolytic solution is applied. It can be obtained by injecting and sealing the outer periphery of the positive electrode active material layer 13 and the negative electrode active material layer 23 with a sealing material 40. Examples of the method of sealing the outer periphery of the positive electrode active material layer 13 and the negative electrode active material layer 23 with the sealing material 40 include a method of applying a liquid sealing material, curing and sealing.
Further, the sealing material 40 may be a frame made of a polymer material durable to the above-mentioned electrolytic solution and having through holes for accommodating the positive electrode active material layer 13 or the negative electrode active material layer 23. .. When the sealing material 40 is a frame body, the positive electrode current collector 11 or the negative electrode current collector 12 is joined to one frame surface of the frame body to seal one end of the through hole, and the other of the frame body is sealed. The lithium ion cell 100 can be obtained by a method of adhering and sealing the frames with the separator inserted on the frame surface.

[Lithium-ion battery module]
The lithium ion battery module of the present invention is configured by using the above-mentioned lithium ion cell 100.
Hereinafter, the first aspect and the second aspect of the lithium ion battery module of the present invention will be described.

[First aspect of lithium-ion battery module]
In the first aspect of the lithium ion battery module of the present invention, the battery outer container for accommodating the power storage element is provided, and the battery outer container includes the first metal sheet and the second metal sheet. It is preferable that the first metal sheet and the second metal sheet have a contact surface in contact with the elastic member and an exposed surface exposed to the outside of the battery outer container.
FIG. 2A is a cross-sectional view schematically showing an example of the first aspect of the lithium ion battery module, and FIG. 2B schematically shows an example of the first aspect of the lithium ion battery module. It is a perspective sectional view which shows.
The lithium-ion battery module 300 shown in FIG. 2A includes a battery outer container 140 for accommodating the power storage element 200, and is located between the positive electrode current collector in the outermost layer of the power storage element 200 and the battery outer container 140. / Alternatively, a conductive elastic member 130 arranged between the negative electrode current collector in the outermost layer of the power storage element 200 and the battery outer container 140 is provided.
The battery outer container 140 has a resin layer 140a, a metal layer 140b, and a resin layer 140c in this order from the inside.
The metal layer 140b has a contact surface in contact with the elastic member 130 and an exposed surface exposed to the outside of the battery outer container 140, and the range in which the contact surface and the exposed surface overlap in the stacking direction is the first. It becomes the metal sheet 110 or the second metal sheet 120.
Specifically, as shown in FIG. 2B, in the stacking direction A, the metal layer 140b comes into contact with the elastic member 130 between the positive electrode current collector in the outermost layer of the power storage element 200 and the battery outer container 140. The first metal sheet 110 is a range in which the surface and the exposed surface exposed on the outside (positive electrode side) of the battery outer container 140 overlap. Further, in the stacking direction A, the contact surface where the metal layer 140b is in contact with the elastic member 130 between the negative electrode current collector of the outermost layer of the power storage element 200 and the battery outer container 140, and the outside (negative electrode side) of the battery outer container 140. The range where the exposed surface exposed to the surface overlaps with the exposed surface is the second metal sheet 120.
The resin layer 140a and the resin layer 140c have a role as an insulating layer, and the first metal sheet 110 and the second metal sheet 120 are insulated from each other.
Since the lithium ion battery module 300 has such a configuration, even if the power storage element is distorted or the electrode thickness is uneven, contact failure does not occur and a current is applied to the current collector on the outermost layer of the power storage element and to the outside. Can be connected to the portion (first metal sheet 110 and second metal sheet 120) from which the current is taken out, and further, the current can be taken out without pulling out the electrode terminal from the battery outer container.
Hereinafter, each configuration of the lithium ion battery module 300 will be described.

(Power storage element)
The power storage element 200 includes a lithium ion cell 100.
The power storage element 200 may have a configuration including one lithium ion cell 100, or may have a configuration in which a plurality of lithium ion cell 100s are stacked in series.
From the viewpoint of improving the output of the lithium ion battery module, the power storage element 200 preferably has a configuration in which a plurality of lithium ion cell 100 are stacked in series. For example, five or more lithium ion cell 100s are connected in series. A laminated structure is preferable, and a structure in which seven or more are laminated in series is more preferable.
When the power storage element 200 has a configuration in which a plurality of lithium ion cell 100s are stacked in series, the positive electrode of one adjacent lithium ion cell 100 and the negative electrode of the other lithium ion cell 100 are arranged. It is preferable that the lithium ion cell 100s are laminated so as to be in contact with each other, that is, in the same direction. When a plurality of lithium ion cell 100 are stacked so as to have the same orientation to form the power storage element 200, if any of the lithium ion cell 200 included in the power storage element 200 is defective, a terminal is used. It is preferable because a normal power storage element 200 can be obtained by simply replacing only the defective lithium ion cell 100 without performing work such as reconnecting.

(Battery outer container)
The battery outer container 140 has a resin layer 140a, a metal layer 140b, and a resin layer 140c in this order from the inside. The resin layer 140a may be arranged so as to electrically insulate the metal layers 140b on the upper side and the lower side in the stacking direction, and the resin layer 140c may be arranged on the upper side and the lower side in the stacking direction. It is arranged as needed according to the size of the exposed surface of 140b.
As such a battery outer container, for example, a composite material of a metal sheet and a polymer sheet, a polymer metal composite film used for a laminated container or the like, a metal can case or the like can be used.
In the battery outer container 140, the metal layer 140b has a contact surface in contact with the elastic member 130 and an exposed surface exposed to the outside of the battery outer container, and the range in which the contact surface and the exposed surface overlap in the stacking direction. Is the first metal sheet 110 or the second metal sheet 120.

The resin layer 140a is preferably a thermosetting resin film.
As the heat-sealing resin film, for example, a film made of heat-sealing resin such as polyethylene (PE), polypropylene (PP), modified polyethylene, modified polypropylene, ionomer, ethylene vinyl acetate (EVA) can be used. ..
The thermosetting resin film also acts as a sealing layer when the power storage element 200 is housed inside. Further, since the thermosetting resin film also has a role as an insulating layer, the first metal sheet 110 and the second metal sheet 120 are insulated from each other.
The thickness of the resin layer 140a is not particularly limited, but is, for example, 10 μm to 1000 μm.

As the metal layer 140b, for example, a metal foil, a metal sheet, or the like can be used, and as the metal, aluminum, nickel, stainless steel, copper, or the like can be used.
The thickness of the metal layer 140b is not particularly limited, but is, for example, 10 μm to 300 μm.

Examples of the resin layer 140c include a polyester film such as polyethylene terephthalate (PET), a heat-sealed resin film exemplified in the resin layer 140a, and a resin sheet such as a polyamide-based synthetic fiber such as polyamide (nylon (registered trademark)). Can be used.
The thickness of the resin layer 140c is not particularly limited, but is, for example, 10 μm to 1000 μm.
The metal layer 140b imparts moisture resistance, air permeability, and chemical resistance to the battery outer container 140, and the resin layer 140c limits the exposed surface of the metal layer 140b so that a short circuit occurs outside the lithium ion cell 100. It is a layer to prevent.

As a specific configuration of the battery outer container 140, for example, polyethylene (PE) / aluminum foil / polyethylene terephthalate (PET) is laminated in this order from the inside; polyethylene (PE) / aluminum foil / nylon (registered trademark). Laminated configuration; Ionomer / Nickel foil / Polyethylene terephthalate (PET) laminated configuration; Ethylene vinyl acetate (EVA) / Aluminum foil / Polyethylene terephthalate (PET) laminated configuration; Ionomer / Aluminum foil / Polyethylene terephthalate Examples thereof include a configuration in which (PET) is laminated.

In the battery outer container 140, the resin layer 140a and the resin layer 140c are subjected to solvent treatment, heat treatment, flame treatment, etc. so that the metal layer 140b comes into contact with the elastic member 130 and on the outside of the battery outer container. It is possible to form an exposed surface to be exposed.
For example, the metal layer 140b can be exposed by subjecting the above-mentioned thermosetting resin to a high temperature treatment using an organic solvent such as toluene, perchloroethylene, trichlorethylene, and carbon tetrachloride.
Further, for example, the metal layer 140b can be exposed by treating the above-mentioned polyester film or resin sheet such as a polyamide synthetic fiber with an organic solvent such as cresol.
Further, by laminating a heat-sealing resin film formed so as to have a predetermined arrangement of the resin layer 140a and a resin sheet of the resin layer 140c on the metal foil and the metal sheet to be the metal layer 140b. It is possible to obtain a battery outer container 140 having a contact surface in contact with the elastic member 130 and an exposed surface exposed to the outside of the battery outer container.
In the battery outer container 140, the metal layer 140b has a contact surface in contact with the elastic member 130 and an exposed surface exposed to the outside of the battery outer container, and the range in which the contact surface and the exposed surface overlap in the stacking direction. Is the first metal sheet 110 or the second metal sheet 120.
The first metal sheet 110 plays the role of a positive electrode terminal, and the second metal sheet 120 plays a role of a negative electrode terminal, so that a direct current can be taken out.

In the lithium ion battery module 300, the ratio of the area of the first metal sheet 110 to the area of the positive electrode current collector in the outermost layer of the power storage element 200 and the second to the area of the negative electrode current collector in the outermost layer of the power storage element 200. The ratio of the area of the metal sheet 120 is preferably 70% or more, more preferably 80% or more, further preferably 85% or more, and 90% or more, respectively. Especially preferable.
Since the first metal sheet 110 and the second metal sheet 120 have such an area ratio, the current can be suitably taken out from the lithium ion battery module 300.
As shown in FIG. 2B, the area of the first metal sheet 110 means that the metal layer 140b is the positive electrode current collector of the outermost layer of the power storage element 200 and the battery outer container 140 in the stacking direction A. It means the area in which the contact surface in contact with the elastic member 130 between them and the exposed surface exposed on the outside (positive electrode side) of the battery outer container 140 overlap.
The area of the second metal sheet 110 is the contact surface where the metal layer 140b is in contact with the elastic member 130 between the negative electrode current collector of the outermost layer of the power storage element 200 and the battery outer container 140 in the stacking direction A. , Means the area of the range where the exposed surface exposed on the outside (negative electrode side) of the battery outer container 140 overlaps.

(Elastic member)
The elastic member 130 has conductivity that can electrically connect between the metal sheet 110 and the power storage element 200, and between the second metal sheet 120 and the power storage element 200, and the power storage element 200 is attached to the battery exterior. There is no limitation as long as it is an elastic body having flexibility that can be deformed by the stress applied to the power storage element 200 by being housed in the container 140, but for example, an elastic body made of metal or metal fiber can be preferably used.
As the metal constituting the elastic member 130, at least one metal selected from the group consisting of nickel, titanium, aluminum, copper, platinum, iron, chromium, tin, zinc, indium, antimony and potassium, or at least one of these metals is used. The containing alloy can be used.
By using these metals as the elastic member 130, high electrical conductivity can be obtained.

As the elastic member 130, for example, an elastic body obtained by mixing or coating a conductive carbon material with a woven fabric or a non-woven fabric of fibers other than plant fibers and / or metals (glass fiber, carbon fiber, etc.) is used. You can also do it.
As the conductive carbon material, at least one or more composed of carbon black, acetylene black, carbon nanotubes, carbon fibers, lignin black, graphite and graphene can be selected.
Further, a woven or non-woven material made of carbon fiber, or a conductive carbon sheet such as sheet-shaped graphite (also referred to as a graphite sheet) can be used.
Of these, a graphite sheet is preferable from the viewpoint of being able to suitably absorb the distortion of the power storage element 200 and having high electrical conductivity.

The elastic member 130 includes an elastic body obtained by mixing the above-mentioned conductive carbon material or metal with an elastic polymer material, or the above-mentioned conductive carbon material or metal on the surface of the elastic polymer material. It is also possible to use an elastic body coated with.
Examples of the polymer material having such elasticity include silicon rubber, fluororubber, epichlorohydrin rubber, acrylic rubber, ethylene acrylic rubber, urethane rubber, nitrile rubber, hydride nitrile rubber, chlorosulfonated polyethylene, and chloroplane. Rubber, EPDM (ethylene-propylene-diene rubber), ethylene rubber, propylene rubber, butyl rubber, butadiene rubber, styrene butadiene rubber, natural rubber, polyisobutylene, polyethylene chloride, isoprene rubber, foamed polypropylene, foamed polyethylene, foamed polyurethane can be used. it can.

The ratio of the area of the elastic member 130 to the area of the positive electrode current collector in the outermost layer of the power storage element 200 or the negative electrode current collector in the outermost layer of the power storage element 200 is preferably 70% or more.
When the elastic member 130 has such an area ratio, it is possible to suitably prevent poor contact due to distortion of the power storage element 200 and unevenness of the thickness of the electrodes. Further, the surface of the lithium ion battery module 300 that functions as a positive electrode and the surface that functions as a negative electrode can be smoothed.
The ratio of the area of the elastic member 130 is more preferably 80% or more, further preferably 85% or more, and particularly preferably 90% or more.

The thickness of the elastic member 130 is not particularly limited as long as it is in contact with both the metal layer of the battery outer container 140 and the positive electrode current collector or the negative electrode current collector of the outermost layer of the power storage element 200, for example. , 50 μm to 500 μm.

The elastic modulus of the elastic member 130 is preferably, for example, 0.01 to 50 MPa / mm at 25 ° C.
For example, when the elastic modulus of the elastic member 130 is smaller than 0.01 MPa / mm, the elastic member 130 may be deformed, and when it is larger than 50 MPa / mm, the contact surface with the power storage element 200. The followability to the device may decrease.
The elastic modulus of the elastic member 130 can be determined by a conventionally known elastic modulus measuring method. For example, the force measuring system grade 1 or higher specified in 4. (Classification of testing machine) of JIS K 6272 or higher. A test device having accuracy is used. For example, it can be obtained by a method of calculating from the amount of displacement when a predetermined load is applied to the elastic member 130 with a tensile compression tester SDWS manufactured by Imada Seisakusho Co., Ltd. When the elastic member 130 is rubber, it can be obtained by the method A described in JIS K 6254: 2010. The allowable strain of the elastic member 130 is preferably, for example, 30 to 99%.

(Manufacturing method of an example of the first aspect of the lithium ion battery module)
As a method of manufacturing the lithium ion battery module 300, for example, after stacking the elastic member 130, the power storage element 200, and the elastic member 130 in this order, the battery exterior provided with the first metal sheet 110 and the second metal sheet 120. It can be obtained by storing it in a container 140 and sealing it.
The battery outer container 140 can be sealed by using heat fusion such as heat sealing, impulse sealing, ultrasonic fusion, and high frequency fusion.

[Second aspect of lithium-ion battery module]
A second aspect of the lithium ion battery module of the present invention includes a first metal sheet, a power storage element, and a battery outer container for accommodating the second metal sheet, and is one of the metal sheets constituting the first metal sheet. A part and a part of the metal sheet constituting the second metal sheet penetrate the battery outer container as a metal member and are pulled out to the outside of the battery outer container, or the first metal sheet and the above It is preferable that the metal member connected to the second metal sheet penetrates the battery outer container and is pulled out to the outside of the battery outer container.

FIG. 3A is a cross-sectional view schematically showing an example of the second aspect of the lithium ion battery module, and FIG. 3B schematically shows an example of the second aspect of the lithium ion battery module. It is a perspective sectional view which shows.
The lithium-ion battery module 400 shown in FIG. 3A includes a battery outer container 145 that houses a first metal sheet 115, a power storage element 200, and a second metal sheet 125.
Specifically, as shown in FIG. 3B, the range of the contact surface where the metal sheet contacts the elastic member 130 between the positive electrode current collector in the outermost layer of the power storage element 200 and the battery outer container 140 is the first. The second metal sheet 125 is the range of the contact surface between the metal sheet 115 and the elastic member 130 between the negative electrode current collector in the outermost layer of the power storage element 200 and the battery outer container 140. Then, in the lithium ion battery module 400, a part of the metal sheet constituting the first metal sheet 115 and a part of the metal sheet constituting the second metal sheet 125 penetrate the battery outer container 145 as the metal member 150. A metal member 150 drawn out of the battery outer container 145 or connected to the first metal sheet 115 and the second metal sheet 125 penetrates the battery outer container 145 and is connected to the battery outer container 145. It is pulled out to the outside.
In the lithium ion battery module 400, the first metal sheet 115 and the second metal sheet 125 and the battery outer container 145 are separate members.
Further, an insulating layer (not shown) is formed on the inner surface of the battery outer container 145, and is connected to the positive electrode current collector of the outermost layer of the power storage element 200 (via a conductive elastic member). The metal sheet 115 and the second metal sheet 125 connected (via a conductive elastic member) to the negative electrode current collector in the outermost layer of the power storage element 200 are insulated from each other.
Since the lithium ion battery module 400 has such a configuration, even if the power storage element 200 is distorted or the thickness of the electrodes is uneven, contact failure does not occur, and the current collector and the outside in the outermost layer of the power storage element 200 are not generated. Can be connected to a portion (first metal sheet 115 and second metal sheet 125) that draws out current.
Hereinafter, each configuration of the lithium ion battery module 400 will be described.

(Metal sheet)
The first metal sheet 115 and the second metal sheet 125 are not particularly limited as long as they are sheets made of a conductive material, and are metal materials such as copper, aluminum, titanium, stainless steel, nickel and alloys thereof. , And a sheet made of the material described as the resin current collector can be appropriately selected and used.
In the lithium ion battery module 400, a part of the metal sheet constituting the first metal sheet 115 and a part of the metal sheet constituting the second metal sheet 125 penetrate through the battery outer container 145 as the metal member 150. It may be pulled out to the outside of the battery outer container 145, or another metal member 150 connected to the first metal sheet 115 and the second metal sheet 125 penetrates the battery outer container 145 and is connected to the battery outer container 145. It may be pulled out to the outside of 145.
In the lithium ion battery module 400, the metal member 150 that is a part of the metal sheet constituting the first metal sheet 115 or another metal member 150 connected to the first metal sheet 115 functions as a positive electrode terminal. To do.
Further, a metal member 150 that is a part of the metal sheet constituting the second metal sheet 125, or another metal member 150 connected to the second metal sheet 125 functions as a negative electrode terminal.
The other metal member 150 connected to the first metal sheet 115 and the second metal sheet 125 is not particularly limited, and a known lead wire or metal tab can be appropriately selected and used.

The ratio of the area of the first metal sheet 115 to the area of the positive electrode current collector in the outermost layer of the power storage element 200, and the area of the second metal sheet 125 to the area of the negative electrode current collector in the outermost layer of the power storage element 200. The ratio is preferably 70% or more, more preferably 80% or more, further preferably 85% or more, and particularly preferably 90% or more.
Since the first metal sheet 115 and the second metal sheet 125 have such an area ratio, the current can be suitably taken out from the lithium ion battery module 400.
In the lithium ion battery module 400, the area of the first metal sheet 115 is the area between the positive electrode current collector in the outermost layer of the power storage element 200 and the battery outer container 140 in FIG. 3B. The area of the contact surface in contact with the elastic member 130, and the area of the second metal sheet 125 is the elastic member 130 between the negative electrode current collector in the outermost layer of the power storage element 200 and the battery outer container 140. The area of the contact surface in contact.

The thickness of the first metal sheet 115 and the second metal sheet 125 is preferably 20 to 80 μm from the viewpoint of preferably extracting an electric current.

(Battery outer container)
The battery outer container 145 is a base material used for a known metal can case, a composite material of a metal sheet and a polymer sheet described in the first aspect of the lithium ion battery module described above, a polymer used for a laminated container, and the like. A metal composite film or the like can be molded into a predetermined shape and used.
However, in the battery outer container 145, it is not necessary to provide a contact surface where the metal sheet comes into contact with the elastic member 130 or an exposed surface where the metal sheet is exposed to the outside of the battery outer container 145.
Further, an insulating layer (not shown) made of a resin layer is formed on the inner surface of the battery outer container 145, and a metal member that functions as a positive electrode terminal or a negative electrode terminal that penetrates the battery outer container 145 and is pulled out to the outside. 150 are isolated from each other.

In the battery outer container 145, the metal member 150 that functions as a positive electrode terminal or a negative electrode terminal penetrates the battery outer container 145 and is pulled out to the outside of the battery outer container 145.
Such a portion penetrating the battery outer container 145 can be formed by performing machining or the like. When the battery outer container 145 is composed of a plurality of members made of the above-mentioned base material, composite material, polymer metal composite film, or the like, the battery outer container 145 is used as a joint portion between the members constituting the battery outer container 145. The metal member can be pulled out as a penetrating portion. Further, when the battery outer container 145 has an opening for accommodating the power storage element 200 or the like, the opening can be set as a portion penetrating the battery outer container 145, and the metal member can be pulled out.
It should be noted that "penetrating and being pulled out to the outside of the battery outer container 145" means that when the battery outer container 145 is sealed, the first metal sheet 115 and the first metal sheet 115 and the first metal sheet 115 and the first metal sheet 115 are used from the sealing portion of the battery outer container 145. The case where the metal member connected to the second metal sheet 125 or the first metal sheet 115 and the metal member connected to the second metal sheet 125 is pulled out to the outside of the battery outer container 145 is also included.

(Other)
In the second aspect of the lithium ion battery module, as the power storage element 200 and the elastic member 130, the same ones as those described in the first aspect of the lithium ion battery module of the present invention can be appropriately selected and used. ..

(Manufacturing method of the second aspect of the lithium ion battery module)
As a method for manufacturing the lithium ion battery module 400, for example, the first metal sheet 115, the elastic member 130, the power storage element 200, the elastic member 130, and the second metal sheet 125 are superposed in this order, and if necessary, a penetration portion is formed in advance. The metal member 150 that functions as a positive electrode terminal or a negative electrode terminal is pulled out from the penetrating portion of the battery outer container 145, and then sealed.
The battery outer container 145 can be sealed by heat fusion such as heat sealing, impulse sealing, ultrasonic fusion, and high frequency fusion.

[Battery pack]
The battery pack means a battery system composed of a plurality of battery modules connected in series or in parallel for the purpose of adjusting the capacity and voltage as a power source according to the application, and other than the battery modules. A charge / discharge control circuit or the like may be combined with the above.

(First aspect of battery pack)
The first aspect of the battery pack of the present invention includes a plurality of lithium ion battery modules, and has a configuration in which the positive electrode and the negative electrode of the lithium ion battery module are connected in series.
FIG. 4 is a cross-sectional view schematically showing an example of the first aspect of the battery pack.
The battery pack 500 shown in FIG. 4 includes a plurality of lithium ion battery modules 300, which are the lithium ion battery modules of the first aspect described above, and the positive electrode and the negative electrode of the lithium ion battery module 300 are connected in series. ing.
In the battery pack 500, the lithium ion battery module 300 is arranged so that the positive electrode terminal of one adjacent lithium ion battery module 300 and the negative electrode terminal of the other lithium ion battery module 300 are in contact with each other, that is, each lithium ion battery module 300. The power storage elements 200 are laminated so that the directions of the power storage elements 200 are the same.
Since the battery pack 500 has such a configuration, the output can be increased.

Since the lithium-ion battery module 300 has an exposed surface in which a metal sheet electrically connected to the current collector is exposed to the outside of the battery outer container, a plurality of lithium-ion battery modules 300 are laminated in the battery pack 500. The lithium-ion battery modules 300 can be easily connected in series to form a battery pack by simply contacting the exposed surfaces without requiring a special member.
From the viewpoint of improving the output of the battery pack, for example, a configuration in which five or more lithium ion battery modules 300 are connected in series is preferable, and a configuration in which seven or more lithium ion battery modules 300 are connected in series is more preferable.
Further, in the lithium ion battery module 300, since the exposed surface functioning as the positive electrode and the exposed surface functioning as the negative electrode are smooth, even if the lithium ion battery modules 300 are connected in series, the electrical connection is good.

Since the battery pack 500 is formed by laminating without using a member connecting a plurality of lithium ion battery modules 300, even if one of the lithium ion battery modules 300 has a defective product, it is formed. By simply replacing the defective product without rewiring the lithium-ion battery module 300, the later good product can be used as it is, which is excellent in maintainability and economy.
Although FIG. 4 shows a battery pack having a configuration including a plurality of lithium ion battery modules 300, a configuration including a plurality of lithium ion battery modules 400 and connecting the positive electrode and the negative electrode of the lithium ion battery module 400 in series. It may be.

(Second aspect of battery pack)
The second aspect of the battery pack of the present invention includes a plurality of lithium ion battery modules, and has a configuration in which the positive electrode and the negative electrode of the lithium ion battery module are connected in parallel.
FIG. 5 is a cross-sectional view schematically showing an example of the second aspect of the battery pack.
The battery pack 600 shown in FIG. 5 includes a plurality of lithium ion battery modules 300, which are the lithium ion battery modules of the first aspect, and the surface of the lithium ion battery module 300 that functions as a positive electrode is on the positive electrode current collector plate 160 side. The surface functioning as the negative electrode is connected in parallel so as to be on the negative electrode current collector plate 170 side.
Since the battery pack 600 has such a configuration, it can be used as a high-capacity power source.

In the lithium ion battery module 300, the metal sheets (110 and 120) electrically connected to the current collector have an exposed surface exposed to the outside of the battery outer container 140. Therefore, in the battery pack 600, the positive electrode current collector plate 160 By using the negative electrode current collector plate 170 and sandwiching the lithium ion battery module 300 between them, the lithium ion battery modules 300 can be connected in parallel to form a battery pack with a simple configuration.
From the viewpoint of improving the life of the battery pack, for example, a configuration in which five or more lithium ion battery modules 300 are connected in parallel is preferable, and a configuration in which seven or more lithium ion battery modules 300 are connected in parallel is more preferable.
Further, since the exposed surface functioning as the positive electrode and the exposed surface functioning as the negative electrode of the lithium ion battery module 300 are smooth, the electrical connection between the positive electrode and the positive electrode current collector plate 160 of the lithium ion battery module 300 and the negative electrode The electrical connection between the negative electrode current collector and the negative electrode current collector plate 170 is good.

The materials constituting the positive electrode current collector plate 160 and the negative electrode current collector plate 170 are not particularly limited, and a highly conductive material known as a current collector plate for a lithium ion battery can be used.
As the constituent material of the current collector plate, for example, metal materials such as aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof are preferable.
From the viewpoint of light weight, corrosion resistance, and high conductivity, aluminum and copper are more preferable, and aluminum is particularly preferable.
The same material may be used for the positive electrode current collector plate 160 and the negative electrode current collector plate 170, or different materials may be used.

Since the battery pack 600 is formed by sandwiching a plurality of lithium ion battery modules 300 between the positive electrode current collector plate 160 and the negative electrode current collector plate 170, one of the lithium ion battery modules 300 has a defective product. Even in such a case, the defective product can be used as it is by simply pulling out the defective product, which is excellent in maintainability and economy.
Although FIG. 5 shows a battery pack having a configuration including a plurality of lithium ion battery modules 300, a configuration including a plurality of lithium ion battery modules 400 and connecting the positive electrode and the negative electrode of the lithium ion battery module 400 in parallel. It may be.

The lithium ion battery module of the present invention is particularly useful as a lithium ion battery module used for mobile phones, personal computers, hybrid vehicles and electric vehicles.

11 Positive electrode current collector 13 Positive electrode active material layer 21 Negative electrode current collector 23 Negative electrode active material layer 30 Separator 40 Encapsulant 100 Lithium ion cell 110, 115 First metal sheet 120, 125 Second metal sheet 130 Elastic member 140, 145 Battery outer container 140a Resin layer 140b Metal layer 140c Resin layer 150 Metal member 160 Positive electrode current collector 170 Negative electrode current collector 200 Power storage element 300, 400 Lithium ion battery module 500, 600 Battery pack

Claims (8)

A lithium ion battery module having a first metal sheet, a power storage element, and a second metal sheet in this order.
The power storage element has a positive electrode current collector, a positive electrode active material layer, a separator, a negative electrode active material layer, and a negative electrode current collector stacked in this order, and has the positive electrode current collector and the negative electrode current collector in the outermost layer. Contains a lithium ion cell having a structure in which an electrolytic solution is sealed by sealing the outer periphery of the positive electrode active material layer and the negative electrode active material layer.
It is arranged between the positive electrode current collector in the outermost layer of the power storage element and the first metal sheet and / or between the negative electrode current collector in the outermost layer of the power storage element and the second metal sheet. Has a conductive elastic member
A lithium ion battery module characterized in that the first metal sheet and the second metal sheet are insulated from each other. A battery outer container for accommodating the power storage element is provided.
The battery outer container includes the first metal sheet and the second metal sheet.
The lithium ion battery module according to claim 1, wherein the first metal sheet and the second metal sheet have a contact surface in contact with the elastic member and an exposed surface exposed to the outside of the battery outer container. A battery outer container for accommodating the first metal sheet, the power storage element, and the second metal sheet is provided.
A part of the metal sheet constituting the first metal sheet and a part of the metal sheet constituting the second metal sheet penetrate the battery outer container as a metal member and are pulled out to the outside of the battery outer container. Or
The lithium ion battery module according to claim 1, wherein the first metal sheet and a metal member connected to the second metal sheet penetrate the battery outer container and are pulled out to the outside of the battery outer container. .. The lithium ion battery module according to any one of claims 1 to 3, wherein the conductive elastic member is a graphite sheet. The lithium ion battery module according to any one of claims 1 to 4, wherein the positive electrode current collector and / or the negative electrode current collector is a resin current collector. The ratio of the area of the first metal sheet to the area of the positive electrode current collector in the outermost layer of the power storage element, the ratio of the area of the second metal sheet to the area of the negative electrode current collector in the outermost layer of the power storage element, Any of claims 1 to 5, wherein the ratio of the area of the elastic member to the area of the positive electrode current collector in the outermost layer of the power storage element or the negative electrode current collector in the outermost layer of the power storage element is 70% or more, respectively. Lithium-ion battery module described in metal. A battery pack including a plurality of lithium ion battery modules according to any one of claims 1 to 6, in which a positive electrode and a negative electrode of the lithium ion battery module are connected in series. A battery pack including a plurality of lithium ion battery modules according to any one of claims 1 to 6, in which a positive electrode and a negative electrode of the lithium ion battery module are connected in parallel.

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