JP6850572B2 - Lithium-ion battery and its manufacturing method - Google Patents

Description

The present invention relates to a lithium ion battery in which a first pole current collector, a first pole active material layer, a separator, a second pole active material layer and a second pole current collector are laminated in this order, and a method for manufacturing the same.

Lithium-ion (secondary) batteries have been widely used in various applications in recent years as high-capacity, compact and lightweight secondary batteries. In a general lithium ion battery, a positive electrode composition layer containing a positive electrode active material and an electrolytic solution is formed on the surface of a positive electrode current collector, and a negative electrode composition layer containing a negative electrode active material and an electrolytic solution is similarly provided. A cell cell formed by laminating a negative electrode formed on the surface of a negative electrode current collector with a separator sandwiched between them is housed in a container as an exterior body.

On the other hand, stationary storage batteries, which can temporarily store the surplus power generated by a large power plant, are attracting attention. As for the storage battery (secondary battery) used for such a stationary storage battery, various types of batteries such as sodium-sulfur batteries have been studied and put into practical use.

Special Table 2015-524994

However, when a conventional lithium ion battery is applied to the above-mentioned stationary storage battery, the thickness of the positive electrode and the negative electrode is generally about 100 μm, so that it is necessary to combine a large number of lithium ion batteries to increase the size. There was a problem that productivity was low and cost was high. Further, when a stationary storage battery is constructed by combining a large number of lithium ion batteries in this way, it is difficult to increase the battery capacity per unit volume because the film thickness is thin.

For the purpose of increasing the battery capacity, a lithium ion battery has been proposed in which substantially rectangular parallelepiped positive electrode and negative electrode are alternately projected from a pair of electrode baths extending in one direction and facing each other, and a separator is arranged between the positive electrode and the negative electrode. (See Patent Document 1). However, since the lithium ion battery proposed in Patent Document 1 also has a film thickness of several hundred μm, the lithium ion battery is oriented in a direction orthogonal to the above-mentioned one direction in order to increase the size. It has a stack structure in which a large number of batteries are stacked, and therefore, the above-mentioned problems have not yet been solved.

The present invention has been made in view of the above-mentioned problems, and is a lithium ion battery capable of increasing in size at low cost and capable of saving space while ensuring an appropriate battery capacity, and a method for manufacturing the lithium ion battery. Is one of the purposes.

In the present invention, a flat battery cell in which a first pole current collector, a first pole active material layer, a separator, a second pole active material layer and a second pole current collector are laminated in this order is sealed in a laminated container. It is applied to a lithium-ion battery in which a laminated battery is housed in a battery container. The thickness of the first polar active material layer and the second polar active material layer is 200 μm or more, the first polar active material layer is a non-bonded body of the first polar active material particles, and the second polar active material layer is. It is a non-binding body of the second polar active material particles, and both the battery cell and the laminated battery have flexibility. By forming bent portions in the laminated battery at predetermined intervals, the laminated battery can be used as a battery container. Inside, a plurality of first surfaces on the first pole current collector side and second surfaces on the second pole current collector side are alternately folded so as to face each other, and the bent portion is in the bending direction of the laminated battery. The first pole current collector, the first pole active material layer, the separator, the second pole active material layer and the second pole current collector are bent and face each other at the bent portion. At least one of the above-mentioned problems is solved by folding the laminated battery so that a predetermined space is formed between the first surfaces and the second surfaces.

Here, it is preferable to provide a plurality of supports that support the first surface or the second surface in a predetermined shape between the first surfaces and the second surfaces that face each other. Further, it is preferable to provide a plurality of current extraction terminals on the side surface of the laminated battery. Further, it is preferable that the support is provided with voids through which gas or liquid can move. The first polar active material layer and the second polar active material layer preferably contain an electrode active material having a coating layer containing a polymer compound.

Further, in the present invention, a flat battery cell in which a first pole current collector, a first pole active material layer, a separator, a second pole active material layer and a second pole current collector are laminated in this order is used as a laminated container. It is applied to a method for manufacturing a lithium ion battery in which a sealed laminated battery is housed in a battery container. The thickness of the first polar active material layer and the second polar active material layer is 200 μm or more, the first polar active material layer is a non-bonded body of the first polar active material particles, and the second polar active material layer is. It is a non-binding body of the second polar active material particles, and both the battery cell and the laminated battery have flexibility, and by forming bent portions in the laminated battery at predetermined intervals, the first in the battery container. It is provided with an arrangement step of alternately bending and arranging a plurality of laminated batteries so that the first surfaces on the pole collector side and the second surfaces on the second pole collector side face each other, and further, the arrangement step is performed. By bending the 1st pole current collector, the 1st pole active material layer, the separator, the 2nd pole active material layer and the 2nd pole current collector at the bent portion, a curved surface continuous with respect to the bending direction of the laminated battery. By providing a step of forming the first surface and a step of arranging a support for supporting the first surface or the second surface between the first surfaces and the second surfaces facing each other, at least one of the above-mentioned problems can be solved. It has been resolved.

According to the present invention, it is possible to provide a lithium ion battery and a method for manufacturing the same, which can be increased in size at low cost and can save space while securing an appropriate battery capacity.

It is a perspective view which shows the lithium ion battery which is one Embodiment of this invention. It is a perspective view which shows the laminated battery which comprises the lithium ion battery which is one Embodiment. It is a figure which shows the manufacturing method of the lithium ion battery which is one Embodiment of this invention. It is a perspective view which shows the support used for the lithium ion battery of one Embodiment. It is a process drawing which shows the manufacturing method of the lithium ion battery of one Embodiment. It is a process drawing which shows the manufacturing method of the lithium ion battery of one Embodiment. It is a partially cutaway perspective view which shows the cell cell used for the lithium ion battery of one Embodiment. It is a perspective view which shows the lithium ion battery which is a modification of this invention. It is a process drawing which shows the manufacturing method of the lithium ion battery which is a modification of this invention. (A) is a cross-sectional view showing a main part of a modified example of the cell of the lithium ion battery of the present invention, (b) is an enlarged cross-sectional view inside an A circle of (a), and (c) is a B circle of (a). It is an inward enlarged sectional view. It is a figure which shows the modification of the lithium ion battery of this invention.

(One Embodiment)
A lithium ion battery according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. It is a perspective view which shows the lithium ion battery which is one Embodiment of this invention, and is the perspective view which shows the laminated battery which comprises the lithium ion battery of one Embodiment.

In these figures, the lithium-ion battery L of the present embodiment includes a laminated battery 20 having a substantially strip-shaped outer shape, which is a substantially plate-shaped outer shape, and a frame 22 which is a form of a battery container accommodating the laminated battery 20. Be prepared. The laminated battery 20 of the present embodiment is formed to have a size of about 10 m in the length direction, about 10 cm in the thickness direction, and about several mm in the thickness direction. The laminated battery 20 is configured by accommodating a lithium secondary cell 1 having a substantially strip shape as shown in FIG. 7 in a laminated container 21, and further decompressing and degassing the inside of the laminated container 21 to seal the battery 20.

As shown in detail in FIG. 2, the laminated container 21 (hereinafter, may be simply referred to as a container 21) is divided into an upper container 21a and a lower container 21b, each of which has a sheet-like member formed into a predetermined shape. It is configured. The upper container 21a and the lower container 21b are formed in substantially the same shape, and the upper container body 21c and the lower container body 21d having one side open, and the upper container body 21c and the lower container body 21d from the ends to the sides. It includes a pair of protruding upper container edge portions 21e and a lower container edge portion 21f. As described above, the lithium secondary cell (hereinafter, also simply referred to as “cell”) 1 is housed in the container 21.

Here, in the present invention, the lithium secondary cell 1 refers to a positive electrode having a positive electrode composition layer containing a positive electrode active material and an electrolytic solution formed on the surface of a positive electrode current collector, and a negative electrode active material and an electrolytic solution. It has a negative electrode in which a negative electrode composition layer containing and is formed on the surface of a negative electrode current collector, and has a structure in which a positive electrode composition and a negative electrode composition are laminated via a separator. It is a battery that does not have a terminal arrangement and an electronic control device (Reference: Japanese Industrial Standard JIS C 8715-2 "A cell and battery system for industrial lithium secondary batteries"). The lithium secondary cell 1 may be abbreviated as a cell.

As shown in detail in FIG. 7, the cell 1 is a substantially flat positive electrode containing a positive electrode active material and an electrolytic solution on the surface of a substantially rectangular plate-shaped positive electrode current collector (first electrode current collector) 7. A negative electrode active material and an electrolytic solution are formed on the surfaces of the positive electrode 2 on which the electrode composition layer (first electrode composition) 5 is formed and the negative electrode current collector (second pole current collector) 8 having a substantially rectangular plate shape. The negative electrode 3 on which the substantially flat negative electrode composition layer (second pole electrode composition) 6 including the above is formed is similarly laminated via the substantially plate-shaped separator 4, and is substantially as a whole. It is formed in the shape of a rectangular plate. As a result, the cell 1 having the opposite positive electrode current collector 7 and the negative electrode current collector 8 in the outermost layer is configured.

More specifically, a frame-shaped seal member 9 is formed on the peripheral edges of the positive electrode current collector 7 and the negative electrode current collector 8, and the positive electrode active material layer 5 and the negative electrode active material layer 6 are formed by the seal member 9. It is formed in the frame. As a result, each of the positive electrode 2 and the negative electrode 3 is sealed by the sealing member 9 via the separator 4. Further, the end portion of the separator 4 is also embedded in the seal member 9.

In the cross-sectional view shown in FIG. 7, the positive electrode current collector 7 and the negative electrode current collector 8 are positioned so as to face each other at predetermined intervals by the sealing member 9, and the separator 4 and the positive electrode current collector 7 and the negative electrode current collector 8 are opposed to each other. The body 8 is also positioned by the seal member 9 so as to face each other at a predetermined interval.

The distance between the positive electrode current collector 7 and the separator 4 and the distance between the negative electrode current collector 8 and the separator 4 are adjusted according to the capacity of the lithium ion battery, and these positive electrode current collector 7 and the negative electrode current collector 7 are adjusted. The positional relationship between the electric body 8 and the separator 4 is determined so that the required spacing can be obtained.

A current collecting member (not shown) is interposed between the upper container 21a and the lower container 21b and the cell 1 respectively, and a part of the current collecting member has an upper container edge portion 21e and a lower container edge portion 21f, respectively. Through it, it extends to the outside of the lithium ion battery L and is used as electrode terminals 13 and 14a. As shown in FIG. 2, the electrode terminals 13 and 14 are alternately formed on one side of the laminated battery 20 (toward the front side in FIG. 2) at predetermined intervals.

As shown in FIG. 3, such a laminated battery 20 is bent a plurality of times in the longitudinal direction (horizontal direction in FIG. 3) at a predetermined interval, so that the laminated battery 20 is bent in the bending direction at a predetermined interval. A plurality of bent portions 20a having continuous curved surfaces are formed, whereby the first surfaces 20b on the positive electrode current collector 7 side are opposed to each other, and similarly, the second surfaces 20c on the negative electrode current collector 8 side are also relative to each other. The spacers 23, which are supports, are arranged between the first surfaces 20b and the second surfaces 20c, respectively, so that the first surfaces 20b and the second surfaces 20c are designated by the spacers 23. It is supported by the shape. Then, the laminated battery 20 is bent in the above-mentioned state and housed in the frame 22 as shown in FIG.

As shown in FIG. 1, in the frame 22, four pipe-shaped members 22b are erected on the four corners of a substantially rectangular flat plate-shaped base 22a in a substantially vertical direction, and the upper ends of the pipe-shaped members 22b are respectively. By being connected by another pipe-shaped member 22c, it is formed into a hollow outer rectangular parallelepiped shape as a whole. The laminated battery 20 having the spacer 23 interposed therebetween is housed in the frame 22, thereby forming the lithium ion battery L of the present embodiment.

The spacer 23 includes a pair of support portions 23a and 23b having a substantially rectangular flat plate shape, as shown in detail in FIG. One ends of the support portions 23a and 23b (one end on the left front side in FIG. 4) are integrated by being connected or the like, while the other end of the support portions 23a and 23b (one end on the right back side in FIG. 4) is a cylinder. It is integrated with the connecting portion 23c by being connected by a connecting portion 23c having a curved surface that looks like it is cut in the longitudinal direction. A truss-shaped reinforcing portion 23d is interposed in the gap formed between the pair of supporting portions 23a and 23b, whereby the gap S surrounded by the supporting portions 23a and 23b and the reinforcing portion 23d is formed. , A gap S in which a gas or a liquid can move forms a predetermined space between the first surfaces 20b and the second surfaces of the above-mentioned laminated battery 20 (see FIG. 1).

Clamp portions 23e are provided at the four corners of the spacer 23 to engage with the pipe-shaped member 22b of the frame 22 and fix the position of the spacer 23 itself. The clamp portion 23e is rotatably provided at one end of a fixing portion 23f formed in an L shape and fixed to the supporting portions 23a, 23b and the connecting portion 23c, and fixed by the locking portion 23h. A moving portion 23g that can be fixed is provided at the other end of the portion 23f. The spacer 23 is arranged in the frame 22 in a state where the locking portion 23h is released and a sufficient distance is provided between the fixing portion 23f and the moving portion 23g (the state in front of the left side in FIG. 4), and then the spacer 23 is arranged in the frame 22. When the spacer 23 is arranged at a predetermined position, the fixing portion 23f and the moving portion 23g are fixed by the locking portion 23h, so that the clamp portion 23e engages with the pipe-shaped member 22b of the frame 22. As a result, the position of the spacer 23 itself in the frame 22 is fixed, and the position of the laminated battery 20 in the state shown in FIG. 1 is also fixed.

Then, the electrode terminals 13 and 14 formed on the side portion of the laminated battery 20 are connected to the collector wires 15 and 16 connecting only one of the electrode terminals 13 and 14, respectively, and are laminated via the collector wires 15 and 16. It is said that the electromotive force of the battery 20, and thus the lithium ion battery L, can be taken out to the outside. Therefore, in the electrode terminals 13 and 14, the electrode terminals 13 and 14 are arranged in a substantially straight line in a state where the laminated battery 20 is bent as shown in FIGS. 1 and 2 (in FIG. 1, the electrode terminals 13 and 14 are substantially linear in the vertical direction). The laminated batteries 20 are formed at predetermined intervals in the longitudinal direction so as to be arranged in a straight line).

The positive electrode active material layer 5 is a non-bonded body containing positive electrode active material particles, and the negative electrode active material layer 6 is a non-bound body containing negative electrode active material particles.

The positive electrode active material layer and the negative electrode active material layer of a known lithium-ion battery are "binding bodies" in which an active material, a conductive auxiliary agent, and the like are bonded to each other using a binder in order to maintain a conductive network of the active material layer. To form.

As used herein, the term "non-binding body" means that the active materials are not bound to each other in a binder. That is, the positive electrode active material particles and the negative electrode active material particles contained in the positive electrode active material layer 5 and the negative electrode active material layer 6 are in a state where they can move according to an external force, respectively, and the positive electrode active material layer 5 and the negative electrode active material layer 5 which are non-bonded bodies and The negative electrode active material layer 6 can be freely deformed in response to an external force. Since the positive electrode active material particles and the negative electrode active material particles contained in the positive electrode active material layer 5 and the negative electrode active material layer 6, respectively, can move following the deformation of the positive electrode active material layer 5 and the negative electrode active material layer 6. The electrical connection between the adjacent positive electrode active material particles and the negative electrode active material particles is not broken. Therefore, even when the lithium ion battery L is significantly deformed, the conductive path can be maintained and the charge / discharge characteristics can be exhibited.

The positive electrode active material layer 5 and the negative electrode active material layer 6, which are non-bonded bodies, preferably have fluid properties. Examples of the property having fluidity include powder, slurry, and suspension, and when the positive electrode active material particles and the negative electrode active material particles are mixed with the electrolytic solution, the mixed weight ratio thereof is adjusted. By doing so, it is possible to obtain a gel-like property or a property similar to that of powder.

In the present invention, in order to form the positive electrode active material layer 5 and the negative electrode active material layer 6, respectively, a positive electrode composition or a positive electrode composition obtained by mixing active material particles (positive electrode active material particles or negative electrode active material particles) with an electrolytic solution. The positive electrode active material layer 5 and the negative electrode active material layer 6 obtained by molding the negative electrode electrode composition into a sheet may be arranged, and the powdery positive electrode active material particles and the negative electrode active material particles are formed into a sheet shape. After that, it is preferable to add an electrolytic solution.

When the positive electrode composition and the negative electrode composition are formed into a sheet, the positive electrode composition and the negative electrode composition are each applied to a sheet-like base material to a predetermined thickness without using a binder, and are non-aqueous. By removing the solvent, it is possible to form a sheet without binding the active materials to each other.

The positive electrode composition contains positive electrode active material particles, and the positive electrode active material particles include composite oxides of lithium and a transition metal (for example, LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ and LiNi _0.8). Co _0.15 Al _0.05 O ₂ ), 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, etc.) Polythiophene, polyacetylene, poly-p-phenylene and polycarbazole) and the like can be mentioned. The volume average particle size of the positive electrode active material is preferably 0.1 to 100 μm, more preferably 1 to 50 μm, and even more preferably 2 to 20 μm from the viewpoint of the electrical characteristics of the battery.

The volume average particle size of the positive electrode active material means the particle size (Dv50) at an integrated value of 50% in the particle size distribution obtained by the laser diffraction / scattering method (also referred to as the microtrack method). The laser diffraction / scattering method is a method of obtaining a particle size distribution using scattered light obtained by irradiating particles with laser light, and for measuring the volume average particle size, a microtrack manufactured by Nikkiso Co., Ltd., etc. Can be used.

Further, the negative electrode electrode composition contains negative electrode active material particles, and as the negative electrode active material particles, graphite, non-graphitizable carbon, amorphous carbon, polymer compound calcined material (for example, phenol resin, furan resin, etc.) is calcined. Carbonized materials, etc.), cokes (eg, pitch coke, needle coke, petroleum coke, etc.), carbon fibers, conductive polymers (eg, polyacetylene and polyquinolin, etc.), tin, silicon, and metal alloys (eg, lithium-tin alloys). , Lithium-silicon alloy, lithium-aluminum alloy, lithium-aluminum-manganese alloy, etc.), composite oxide of lithium and transition metal (for example, Li ₄ Ti ₅ O ₁₂ etc.) and the like. 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.

The volume average particle size of the negative electrode active material can be obtained in the same manner as that of the positive electrode active material.

The positive electrode active material particles and the negative electrode active material particles are preferably coated active material particles in which at least a part of the surface is coated with a coating layer made of a coating agent containing a coating resin and a conductive auxiliary agent. In the case of the coated active material particles, the flexibility and conductivity of the positive electrode active material layer 5 and the negative electrode active material layer 6 are further improved, and the electrochemical reaction between the electrolytic solution and the active material generated during charging and discharging can be suppressed. It is considered that the deterioration of the electrolytic solution can be suppressed and the cycle characteristics are improved.

In the present invention, the coating means a state in which the coating agent is attached to at least a part of the surface of the active material particles, and also includes a state in which the coating agent is scattered on the surface of the active material particles. The state in which the coating agent is attached to the surface of the active material particles can be confirmed by observing a magnified observation image of the coating active material particles obtained by using a scanning electron microscope or the like.

The coating agent contains a coating resin, and when the positive electrode active material particles and the negative electrode active material particles are coated with the coating agent, the volume change of the electrode is alleviated and the expansion of the electrode can be suppressed. As the coating resin, a resin that absorbs the electrolytic solution and swells can be used, and specific examples thereof include vinyl resin, urethane resin, polyester resin, polyamide resin, epoxy resin, polyimide resin, silicone resin, and phenol. Examples thereof include resins, melamine resins, urea resins, aniline resins, ionomer resins, and polycarbonates. Of these, vinyl resin is preferable.

The vinyl resin is usually a resin containing the vinyl monomer (a) as an essential constituent monomer, and is represented by the vinyl monomer (a1) having a carboxyl group or an acid anhydride group as the vinyl monomer (a) and the following general formula (1). It is preferable that the resin contains the represented vinyl monomer (a2) as an essential constituent monomer.
CH ₂ = C (R ¹ ) COOR ² (1)
[In the formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is a branched alkyl group having 4 to 36 carbon atoms. ]

Examples of the vinyl monomer (a1) having a carboxyl group or an acid anhydride group include a vinyl group-containing monocarboxylic acid [(meth) acrylic acid, crotonic acid, itaconic acid, etc.], a vinyl group-containing dicarboxylic acid [(anhydrous) maleic acid, etc. Fumaric acid, (anhydrous) itaconic acid, citraconic acid, mesaconic acid, etc.] and the like are mentioned, and among these, (meth) acrylic acid is preferable, and methacrylic acid is more preferable. In addition, in this specification, (meth) acrylic acid means methacrylic acid and / or acrylic acid.

The vinyl monomer (a1) can also be used as a salt with an alkali metal (sodium, lithium, etc.). When the vinyl monomer (a1) is used as a salt, the vinyl monomer (a1) which is a salt may be polymerized, or the resin may be neutralized to form a salt.

In the vinyl monomer (a2) represented by the general formula (1), R ¹ represents a hydrogen atom or a methyl group, and is preferably a methyl group.

R ² is a residue obtained by removing a hydroxyl group from a branched alkyl alcohol having 4 to 36 carbon atoms, and specific examples thereof include a sec-butyl group, a tert-butyl group, a 1-methylbutyl group, a 1-ethylpropyl group, and 1, 1-dimethylpropyl group, 1-methylpentyl group, 1-ethylbutyl group, 1-methylhexyl group, 1-ethylpentyl group, 1-methylheptyl group, 1-ethylhexyl group, 1-methyloctyl group, 1-ethylheptyl Group, 1-methylnonyl group, 1-ethyloctyl group, 1-methyldecyl group, 1-ethylnonyl group, 1-butyleicosyl group, 1-hexyloctadecyl group, 1-octylhexadecyl group, 1-decyltetradecyl group, 1-Undecyltridecyl group, iso-butyl group, 2-methylbutyl group, 2-ethylpropyl group, 2,2-dimethylpropyl group, 2-methylpentyl group, 2-ethylbutyl group, 2-methylhexyl group, 2 -Ethylpentyl group, 2-methylheptyl group, 2-ethylhexyl group, 2-methyloctyl group, 2-ethylheptyl group, 2-methylnonyl group, 2-ethyloctyl group, 2-methyldecyl group, 2-ethylnonyl group, 2 -Hexyl octadecyl group, 2-octyl hexadecyl group, 2-decyl tetradecyl group, 2-undecyl tridecyl group, 2-dodecyl hexadecyl group, 2-tridecyl pentadecyl group, 2-decyl octadecyl group, 2- Examples thereof include a tetradecyl octadecyl group, a 2-hexadecyl octadecyl group, a 2-tetradecyl eicosyl group and a 2-hexadecyl eicosyl group, and a 2-ethylhexyl group and a 2-decyl tetradecyl group are preferable.

Examples of the vinyl monomer (a2) represented by the general formula (1) include a vinyl monomer obtained by esterifying (meth) acrylic acid and the branched alkyl alcohol having 4 to 36 carbon atoms by a known method. 2-Ethylhexyl (meth) acrylate is preferable, and 2-ethylhexyl methacrylate is more preferable.

Further, as the constituent monomer of the vinyl resin, in addition to the vinyl monomer (a1) having a carboxyl group or an acid anhydride group and the vinyl monomer (a2) represented by the above general formula (1), a copolymerizable vinyl The monomer (a3) may be contained.

Examples of the copolymerizable vinyl monomer (a3) containing no active hydrogen include the following (a31) to (a38).

(A31) Ester of monoalcohol having 1 to 18 carbon atoms and (meth) acrylic acid: methyl (meth) acrylate, ethyl (meth) acrylate, decyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate And benzyl (meth) acrylate and the like.

(A32) Ester of poly (n = 2 to 30) oxyalkylene (2 to 4 carbon atoms) alkyl (1 to 18 carbon atoms) ether and (meth) acrylate: Monomethyl ether of 10 mol of ethylene oxide adduct of methanol Ester with (meth) acrylic acid, ester with monomethyl ether with 10 mol of propylene oxide adduct and (meth) acrylic acid, etc.

(A33) Nitrogen element-containing vinyl compound: N, N-dimethylacrylamide, N, N-dibenzylacrylamide, N-vinylpyrrolidone, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) Acrylate, t-butylaminoethyl (meth) acrylate, morpholinoethyl (meth) acrylate, N-vinyl-2-pyrrolidone, etc., and quaternized products thereof.

(A34) Vinyl hydrocarbons: ethylene, propylene, butene, isobutylene, penten, heptene, diisobutylene, octene, dodecene, octadecene, styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethylstyrene, isopropylstyrene , Butyl styrene, phenyl styrene, cyclohexyl styrene, benzyl styrene and the like.

(A35) Vinyl ester: vinyl acetate, vinyl propionate, vinyl butyrate, diallyl adipate, isopropenyl acetate, vinyl methoxyacetate, vinyl benzoate, diallyl phthalate, methyl-4-vinylbenzoate, acetoxystyrene and the like.

(A36) Vinyl ether: Vinyl methyl ether, vinyl butyl ether, vinyl 2-ethylhexyl ether, vinyl-2-methoxyethyl ether, methoxybutadiene, vinyl-2-ethyl mercaptoethyl ether, dialyloxyethane, trialiloxietan, tetraari Loxybutane, tetrametaaryloxietan, vinylphenyl ether, phenoxystyrene, etc.

(A37) Vinyl ketone: vinyl methyl ketone, vinyl ethyl ketone, vinyl phenyl ketone and the like.

(A38) Vinyl sulfonic acid: vinyl sulfonic acid, styrene sulfonic acid, 2-acrylamide-2-methylpropane sulfonic acid, salts with alkali metals and the like.

Among those exemplified as (a3) above, (a31), (a32), (a33) and (a38) are preferable from the viewpoint of withstand voltage, and (a31) is more preferable, and methyl (meth) is preferable. ) Acrylate, ethyl (meth) acrylate, butyl (meth) acrylate are particularly preferable. In addition, in this specification, (meth) acrylate means methacrylate and / or acrylate.

The contents of the vinyl monomer (a1) having a carboxyl group or an acid anhydride group, the vinyl monomer (a2) represented by the above general formula (1), and the copolymerizable vinyl monomer (a3) are the constituent dimers of the polymer. Based on the total weight of the body, (a1) is 0.1 to 80% by weight, (a2) is 0.1 to 99.9% by weight, and (a3) is 0 to 99.8% by weight. Is preferable.

When the respective contents are within the above ranges, the movement of the positive electrode active material particles and the negative electrode active material particles becomes good in the positive electrode active material layer 5 and the negative electrode active material layer 6.

A more preferable content is 15 to 60% by weight of (a1), 5 to 60% by weight of (a2), and 5 to 80% by weight of (a3), and a more preferable content is 25 to 80% by weight of (a1). 50% by weight, (a2) is 15 to 45% by weight, and (a3) is 20 to 60% by weight.

When a vinyl resin is used as the coating resin, the lower limit of the number average molecular weight of the vinyl resin is preferably 3,000, more preferably 50,000, still more preferably 100,000, and particularly preferably 200,000. The upper limit is preferably 2,000,000, more preferably 1,500,000, still more preferably 1,000,000, and particularly preferably 800,000.
The number average molecular weight can be determined by gel permeation chromatography (hereinafter abbreviated as GPC) measurement under the following conditions.
-Device: Alliance GPC V2000 (manufactured by Waters)
・ Solvent: Ortodichlorobenzene ・ Standard substance: Polystyrene ・ Detector: RI
-Sample concentration: 3 mg / ml
-Column stationary phase: PLgel 10 μm, two MIXED-B in series (manufactured by Polymer Laboratories)
-Column temperature: 135 ° C

The vinyl resin used as the coating resin can be produced by a known polymerization method (bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, etc.) using a monomer.

In the polymerization, known polymerization initiators {azo-based initiators [2,2'-azobis (2-methylpropionitrile), 2,2'-azobis (2,4-dimethylvaleronitrile, etc.)], peroxides It can be carried out using a system initiator (benzoyl peroxide, di-t-butyl peroxide, lauryl peroxide, etc.)}.

The amount of the polymerization initiator used is usually 0.01-5% by weight based on the total weight of the constituent monomers.

Solvents used in the case of solution polymerization include esters (eg esters having 2 to 8 carbon atoms such as ethyl acetate and butyl acetate), alcohols (eg alcohols having 1 to 8 carbon atoms such as methanol, ethanol and octanol), and the like. Hydrocarbons (for example, hydrocarbons having 4 to 8 carbon atoms such as n-butane, cyclohexane and toluene) and ketones (for example, ketones having 3 to 9 carbon atoms such as methyl ethyl ketone) can be mentioned, and the amount used is the total of the constituent monomers. Usually 5 to 900% based on weight.

Examples of the dispersion medium used in the case of emulsion polymerization and suspension polymerization include water, alcohol (for example, ethanol), ester (for example, ethyl propionate) and light naphtha, and examples of the emulsifier include higher fatty acids (10 to 24 carbon atoms). ) Metal salts (eg sodium oleate and sodium stearate), higher alcohols (10 to 24 carbon atoms) sulfate ester metal salts (eg sodium lauryl sulfate), tetramethyldecine ethoxylated, sodium sulfoethyl methacrylate, dimethyl methacrylate Aminomethyl and the like can be mentioned. Further, polyvinyl alcohol, polyvinylpyrrolidone and the like may be added as stabilizers.

In solution polymerization, emulsion polymerization and suspension polymerization, the concentration of the constituent monomer contained in the solution or dispersion is usually 5 to 95% by weight.

For polymerization, known chain transfer agents such as mercapto compounds (dodecyl mercaptan and n-butyl mercaptan, etc.) and halogenated hydrocarbons (carbon tetrachloride, carbon tetrabromide, benzyl chloride, etc.) can be used. The amount used is usually 2% by weight or less based on the total weight of the constituent monomers.

The temperature inside the system in the polymerization reaction is usually −5 to 150 ° C., and the end point of the reaction can be determined by measuring the amount of unreacted monomer. The amount of unreacted monomer at the end point of the polymerization reaction is 5% by weight or less based on the total weight of the constituent monomers normally used.

As the conductive auxiliary agent contained in the coating agent, it can be selected and used from materials having conductivity.

Materials with conductivity include metals [aluminum, stainless steel (SUS), silver, gold, copper and titanium, etc.], conductive carbon [graphite, carbon black, acetylene black, vulcan (registered trademark), and ketjen black (registered). Trademarks), Black Pearl (registered trademark), Furness Black, Channel Black, Thermal Lamp Black, Carbon Nanotubes (Single-walled Carbon Nanotubes and Multi-walled Carbon Nanotubes, etc.), Carbon Nanohorns, Carbon Nanoballoons, Hard Carbon, Fullerenes, etc.], and these Examples thereof include, but are not limited to these.

These conductive aids may be used alone or in combination of two or more. Moreover, these alloys or metal oxides may be used. From the viewpoint of electrical stability, aluminum, stainless steel, carbon, silver, gold, copper, titanium and mixtures thereof are preferable, silver, gold, aluminum, stainless steel and carbon are more preferable, and carbon is more preferable. is there. The conductive auxiliary agent includes a non-conductive material such as a particle-based ceramic material and a resin material coated with a conductive material (a metal material among the above-mentioned conductive auxiliary agent materials) by plating or the like, and a non-conductive material. A mixture of a conductive material and a conductive material (a metal material among the above-mentioned conductive aid materials) can also be used.

The shape of the conductive auxiliary agent is not particularly limited, and those having a shape such as a spherical shape, an indefinite shape, a fibrous shape, a single particle shape, an agglomerate, or a combination thereof can be used. Therefore, it is preferable that it is an agglomerate of fine particles having a primary particle diameter of 5 to 50 nm. The shape of the conductive auxiliary agent can be obtained by observing a magnified observation image of the conductive auxiliary agent obtained by using a scanning electron microscope or the like and measuring the particles in the field of view.

The weight ratio of the coating resin contained in the coating agent to the conductive auxiliary agent is preferably coating resin: conductive auxiliary agent = 100: 1 to 100: 200, and more preferably 100: 5 to 100: 100. Within this range, the conductivity of the positive electrode active material layer 5 and the negative electrode active material layer 6 becomes good.

The coating active material particles are, for example, a resin in which positive electrode active material particles or negative electrode active material particles are placed in a universal mixer and stirred at 30 to 500 rpm, and a coating resin and a conductive auxiliary agent used as necessary are mixed with an organic solvent. The solution is added dropwise over 1 to 90 minutes, and if necessary, the conductive additive to be used is mixed, the temperature is raised to 50 to 200 ° C. with stirring, the pressure is reduced to 0.007 to 0.04 MPa, and then 10 to 150 minutes. It can be obtained by holding.

The proportion of the coating resin contained in the resin solution is preferably 10 to 50% by weight based on the weight of the resin solution. As the organic solvent used in the resin solution, an organic solvent capable of dissolving the coating resin can be selected.

It can be confirmed that the coating active material particles are obtained by observing the magnified observation image of the coating active material particles obtained by using a scanning electron microscope or the like.

When the positive electrode composition and the negative electrode composition are formed, respectively, as the positive electrode composition and the negative electrode composition, the positive electrode active material particles and the negative electrode active material particles are mixed with an electrolytic solution or a non-aqueous solvent, respectively. It is preferably a mixture obtained, and more preferably a slurry-like mixture. In this case, the weights of the positive electrode active material particles and the negative electrode active material particles contained in the positive electrode composition and the negative electrode composition are preferably 10 to 60% by weight based on the weight of the electrolytic solution or the non-aqueous solvent. ..

As the electrolytic solution, a known electrolytic solution obtained by mixing an electrolyte and a non-aqueous solvent used in the production of a known lithium ion battery can be used.

As the electrolyte, a normal is can be used such as those used in the electrolytic solution, the lithium salt of an inorganic acid _{(LiPF 6, LiBF 4, LiSbF} 6, LiAsF 6 , and LiClO _4, etc.) and a lithium salt of an organic acid [LiN ( CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) _2, LiC (CF ₃ SO ₂ ) _3, etc.], etc., and one of these electrolytes may be used alone or two. The above may be used together. _{Among these, LiPF 6} is preferable from the viewpoint of battery output and charge / discharge cycle characteristics.

As the non-aqueous solvent, those used in ordinary electrolytic solutions can be used, and lactones, cyclic or chain carbonates, chain carboxylic acid esters, cyclic or chain ethers, phosphoric acid esters, nitrile compounds, and amides can be used. Compounds, sulfones, sulfolanes and the like and mixtures thereof and the like can be used. One of these non-aqueous solvents may be used alone, or two or more thereof may be used in combination.

Among the non-aqueous solvents, lactone, cyclic carbonate, chain carbonate and phosphoric acid ester are preferable from the viewpoint of battery output and charge / discharge cycle characteristics, and lactone, cyclic carbonate and chain carbonate are more preferable. It is an ester, and more preferably, a mixed solution of a cyclic carbonate ester and a chain carbonate ester. Particularly preferred is propylene carbonate (PC) or a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC).

The concentration of the electrolyte contained in the electrolytic solution is preferably 0.1 to 3 mol / L, more preferably 0.5 to 2 mol / L, based on the volume of the electrolytic solution.

In the present invention, the positive electrode active material layer 5 and the negative electrode active material layer 6 preferably contain a fibrous conductive filler together with the above-mentioned coating active material particles from the viewpoint of reducing ionic resistance and the like. Examples of the fibrous conductive filler include carbon fibers such as PAN-based carbon fibers and pitch-based carbon fibers, conductive fibers obtained by uniformly dispersing a metal or graphite having good conductivity in synthetic fibers, and stainless steel. Examples thereof include metal fibers obtained by fiberizing metal, 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 conductive resin. Among these conductive fibers, carbon fiber is preferable.

The fibrous conductive filler preferably has an average fiber length of 100 to 1000 μm, more preferably 110 μm to 600 μm, and particularly preferably 150 μm to 500 μm, from the viewpoint of ion resistance, strength of the active material layer, and the like. The average fiber diameter is preferably 0.1 to 100 μm, more preferably 0.5 to 2.0 μm.

When the positive electrode active material layer 5 and the negative electrode active material layer 6 contain a fibrous conductive filler, the proportion of the fibrous conductive filler may be 0.5 to 5% by weight based on the weight of the coating active material particles. preferable.

When the positive electrode active material layer 5 and the negative electrode active material layer 6 contain a fibrous conductive filler, a positive electrode composition containing positive electrode active material particles, a fibrous conductive filler, and an electrolytic solution in each of the positive electrode 2 and the negative electrode 3. It is preferable to fill the negative electrode composition containing the negative electrode active material particles, the fibrous conductive filler, and the electrolytic solution, respectively, to form the positive electrode active material layer 5 and the negative electrode active material layer 6.

The thickness of the positive electrode active material layer 5 and the negative electrode active material layer 6 is preferably 200 μm or more. It is more preferably 500 μm or more, still more preferably 1000 μm or more. If it is thicker than this thickness, the amount of active material per unit volume increases, and a battery having a large storage capacity can be obtained.

The separator 4 includes a hydrocarbon resin such as polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP), a porous film made of polyolefin (polyethylene, polypropylene, etc.), and a multilayer film of a porous film (for example, PP / PE / Laminates having a three-layer structure of PP, etc.), non-woven fabrics made of synthetic fibers (polyester fibers, aramid fibers, etc.), glass fibers, etc., and those with ceramic fine particles such as silica, alumina, and titania attached to their surfaces, etc. A known separator for a lithium ion battery or the like can be used.

The thickness of the separator 4 can be adjusted depending on the use of the lithium ion battery, but in the use of electronic devices such as mobile devices, the thickness of the separator 4 is preferably 5 to 100 μm in a single layer or a multilayer, and more preferably 10 to 50 μm. Is.

The pore diameter of the separator 4 made of the porous film or the multilayer film thereof is preferably 1 μm or less (usually, the pore diameter is about several tens of nm) at the maximum. When a non-woven fabric is used, the thickness of the separator 4 is preferably 5 to 200 μm, particularly preferably 10 to 100 μm.

The positive electrode current collector 7 and the negative electrode current collector 8 are a metal current collector or a resin current collector, and are known metal current collectors, as well as Japanese Patent Publication No. 2012-150905 and International Publication No. WO2015 / 005116, respectively. The known resin current collectors and the like described in the above can be used.

As the metal collector, a metal collector generally used for lithium ion batteries can be used, and copper, aluminum, titanium, nickel, tantalum, niobium, hafnium, zirconium, zinc, tungsten, bismuth, antimon and these Examples thereof include alloys containing one or more and current collectors made of one or more metals selected from the group consisting of stainless alloys.

The form of the base material of the metal current collector may be any of a thin plate shape, a metal foil shape and a mesh shape, and a metal layer is formed on the surface of the base material of the metal current collector by a method such as sputtering, electrodeposition and coating. May be formed.

The resin current collector is a current collector formed of a conductive polymer material or a polymer obtained by imparting conductivity to a non-conductive polymer material.

Examples of the conductive polymer material include polyaniline, polypyrrole, polythiophene, polyacetylene, polyparaphenylene, polyphenylene vinylene, polyacrylonitrile, polyoxadiazole and the like. For the purpose of improving the conductivity of the resin current collector containing the conductive polymer material, it is preferable to further contain a conductive filler described later.

Non-conductive polymer materials 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 and mixtures thereof. Be done.

As the non-conductive polymer material, polyethylene (PE), polypropylene (PP), polymethylpentene (PMP) and polycycloolefin (PCO) are preferable, and polyethylene (PE) is more preferable from the viewpoint of electrical stability. , Polypropylene (PP) and Polymethylpentene (PMP).

The polymer obtained by imparting conductivity to the non-conductive polymer material can be obtained by mixing the non-conductive polymer material and the conductive filler, and the conductive filler is obtained from the material having conductivity. Selected from fillers. Preferably, from the viewpoint of suppressing ion permeation in the current collector, it is preferable to use a filler obtained from a material having no conductivity with respect to ions used as a charge transfer medium. Specific examples thereof include fillers obtained from carbon materials, alloy materials such as aluminum, gold, silver, copper, iron, platinum, chromium, tin, indium, antimony, titanium, nickel and stainless steel (SUS). It is not limited to these. Among them, from the viewpoint of corrosion resistance, a filler obtained from aluminum, stainless steel, a carbon material or nickel is preferable, and a filler obtained from a carbon material is more preferable. These conductive fillers may be used alone or in combination of two or more. As the conductive filler, a particle-based ceramic material or a resin material coated with the metal shown above by plating or the like can also be used.

The shape of the conductive filler may be a particle shape, a fibrous shape, or an aggregate thereof.

The resin current collector can be obtained by a known method described in Japanese Patent Publication No. 2012-150905 and International Publication No. WO 2015/005116, and as a specific example, acetylene black as a conductive filler in polypropylene can be obtained. After dispersing 5 to 20 parts of the above, rolled with a hot press machine and the like can be mentioned. Further, the thickness thereof is not particularly limited, and the same as known ones or appropriately modified ones can be applied.

As the positive electrode current collector 7 and the negative electrode current collector 8, the metal current collector or the resin current collector may be used as they are, or those having a conductive layer to be described later may be used on the surface thereof, from the viewpoint of battery characteristics and the like. Therefore, it is preferable that it is a metal current collector or a resin current collector on which a conductive layer is formed.

A current collector member arranged so as to be electrically connected to each current collector between the inner surface of the upper container 21a and the positive electrode current collector 7 and between the inner surface of the lower container 21b and the negative electrode current collector 8. It is preferable to have.

The current collecting member is preferably in a substantially flat plate shape having protrusions serving as electrode terminals 13 and 14, and a conductive metal foil such as a copper foil or an aluminum foil can be used, and the surface of the conductive metal foil is the same. It is also possible to use a surface-treated material obtained by applying another conductive substance such as carbon to the surface. The shape of the protruding portion is not limited as long as the current can be taken out, and a copper wire or the like can be used.

When a resin current collector is used as the positive electrode current collector 7 and the negative electrode current collector 8, it is preferable to use a substantially flat plate-shaped current collector member having protrusions serving as electrode terminals 13 and 14.

The material constituting the seal member is not particularly limited as long as it has adhesiveness to the positive electrode current collector 7 and the negative electrode current collector 8 and is durable against the electrolytic solution, but a polymer material is preferable. , Thermosetting polymer materials are more preferred. Specific examples thereof include epoxy-based resins, polyolefin-based resins, polyurethane-based resins, and polyvinylidene fluoride resins, and epoxy-based resins are preferable because they have high durability and are easy to handle.

The sealing member is preferably formed in the form of a double-sided tape, that is, by applying the above-mentioned thermosetting resin or the like on both sides of a flat base material, or using a known sealing film or the like. As the seal film, a seal film having a three-layer structure (a film in which a modified polypropylene film is laminated on top of a polyethylene naphthalate film, etc.) or the like can be used. The seal film can be sealed by heat-pressing using a known sealing device such as an impulse sealer.

The container 21 obtained by sealing the upper container edge portion 21e and the lower container edge portion 21f with a sealing member includes a positive electrode current collector 7, a positive electrode active material layer 5, a separator 4, a negative electrode active material layer 6, and a negative electrode. A cell 1 in which the current collectors 8 are stacked in this order is housed as a power generation unit, and this power generation unit has flexibility.

The positive electrode active material layer 5 and the negative electrode active material layer 6 are non-bonded bodies of the active material particles, respectively, and the positive electrode active material layer 5 and the negative electrode active material layer 6 can be freely deformed according to an external force. A flexible power generation unit can be obtained by forming a laminated body using the positive electrode current collector 7, the separator 4, and the negative electrode current collector 8.

The container 21 is selected from the viewpoint that the positive electrode composition and the negative electrode composition can be stably stored in the container 21, and it is particularly preferable that the container 21 has flexibility. In addition, the container 21 is preferably made of an insulating material in consideration of the possibility of contact between the electrode composition and the container 21, and is preferably a positive electrode current collector, a positive electrode active material layer, a separator, and a negative electrode activity. It is preferably made of a material having airtightness in consideration of sealing (preferably vacuum sealing) in a state where the power generation unit formed by laminating the material and the negative electrode current collector in order is housed inside.

The container 21 is a container made of a laminated film. As the laminate film, a composite film in which a metal layer is interposed between an outer layer containing a heat-resistant resin film and an inner layer containing a thermoplastic resin film can be used, and as the heat-resistant resin film, a polyamide resin or a polyester resin is stretched. A film or the like can be preferably used, and an unstretched polyolefin film or the like can be preferably used as the thermoplastic resin film.

As the metal layer, a layer made of aluminum foil, stainless steel foil, copper foil or the like can be used. The heat-resistant resin film means that the melting point of the resin film is higher than the melting point of the thermoplastic resin film as the inner layer, and when the heat-resistant resin film is used as the outer layer, the thermoplastic resin film becomes the inner layer. Only the resin film can be sufficiently heated and melted, and the heat seal of the battery outer container can be reliably performed.

As an example of the laminated film, among the surfaces of the metal layer such as aluminum or nickel, the first surface which is the outer surface of the container 21 is coated with a heat-resistant resin (polyethylene resin, polyester resin, etc.) and becomes the inner surface of the container 21. A film coated with a thermoplastic resin (polyethylene, polypropylene, etc.) on the second surface can be raised.

The laminated battery 20 in which the container 21 is flexible can be bent together with the flexible cell 1. In the case of a conventional lithium ion battery, cracks may occur in the active material layer or peeling at the interface with the current collector due to bending, but the positive electrode active material contained in the cell 1 used in the present invention. Since the layer 5 and the negative electrode active material layer 6 are non-bonded bodies of the positive electrode active material particles and the negative electrode active material particles, respectively, the positive electrode active material particles and the negative electrode active material particles generate voids or the like inside the active material layer. It can be deformed while maintaining the contact between the active material particles.

When the positive electrode active material particles and the negative electrode active material particles are coated active material particles in which at least a part of the surface is coated with a coating layer made of a coating agent containing a coating resin and a conductive auxiliary agent, the coating layer is an active material. It acts as a lubricating layer at the contact portion between the particles, and can further assist the movement of the active material particles at the contact portion. Therefore, the coated active material particles can move more easily without forming voids in the contact portion with the adjacent active material particles, and even when the positive electrode active material layer 5 and the negative electrode active material layer 6 are deformed. , The contact between the active material particles can be maintained even better, which is preferable.

In the cell 1 used in the present invention, since the positive electrode active material particles and the negative electrode active material particles are not bound, the active material particles can move while maintaining contact with the adjacent active material particles. As a result, even if the laminated battery 20 is bent, the positive electrode current collector 7 and the negative electrode current collector 8 are separated from each other without causing cracks in the active material layer or peeling at the interface with the current collector. The conductive path can be maintained, and sufficient charge / discharge characteristics can be continuously exhibited.

The laminated battery 20 thus obtained can be made flexible as a whole. As a result, the laminated battery 20 can be bent along the longitudinal direction and the lateral direction. In addition, even if the laminated battery 20 is bent in two directions in this way, a conductive path between the positive electrode current collector 7 and the negative electrode current collector 8 can be secured, and sufficient charge / discharge characteristics are exhibited. You can continue.

Next, the method for manufacturing the lithium ion battery of the present embodiment will be described with reference to FIGS. 5 and 6.

First, as shown in FIG. 5, a strip-shaped (long sheet-shaped) positive electrode current collector sheet 7 wound in a roll shape is placed on a support member (not shown) in a predetermined transport direction (from the right in FIG. 5). It is conveyed in the horizontal direction to the left) and continuously supplied, and as shown in detail in FIG. 6A, an upper wall portion 31a is formed on the peripheral edge of the upper surface of the continuously supplied positive electrode current collector sheet 7. To do.

The upper wall portion 31a (and the lower wall portion 31b described later) constitutes the seal member 9, and the method for forming the upper wall portion 31a and the lower wall portion 31b may be appropriately selected from well-known ones. In the example shown in FIG. 5, the material forming the seal member 9 is melted and dropped onto the positive electrode current collector sheet 7 by the nozzle 32 to form the upper wall portion 31a (and the lower wall portion 31b). .. Alternatively, the upper wall portion 31a (and the lower wall portion 31b) may be formed at a predetermined position on the positive electrode current collector sheet 7 by an inkjet device.

Next, as shown in FIG. 6B, the positive electrode active material and the electrolytic solution forming the positive electrode active material layer 5 are formed in the rectangular space defined by the upper wall portion 31a and the positive electrode current collector sheet 7. One of the mixture of and is dropped by the nozzle 33 and filled to at least the height of the upper wall portion 31a, so that the positive electrode active material is filled in the space defined by the upper wall portion 31a and the positive electrode current collector sheet 7. Layer 5 is filled and formed. Further, after this filling, the positive electrode current collector sheet 7 may be vibrated and impacted by the vibration applying means (not shown) to uniformly disperse the positive electrode active material.

Next, the upper surface of FIG. 6 (c) of the positive electrode active material layer 5 which is filled and formed in advance in a predetermined size, more specifically, in the space defined by the upper wall portion 31a and the positive electrode current collector sheet 7. As shown in FIG. 6D, the separator 4 cut to the size of covering is arranged on the upper surface of the positive electrode active material layer 5 in the drawing.

The method of arranging the separator 4 on the positive electrode active material layer 5 may be appropriately selected from well-known ones. In the example shown in FIG. 6C, after the separator 4 is held by the vacuum chuck 34, the vacuum chuck is used. 34 is placed above the positive electrode active material layer 5, and the vacuum chuck 34 is lowered until the separator 4 reaches the upper surface of the positive electrode active material layer 5, and then the holding by the vacuum chuck 34 is released. Has been done. Alternatively, as shown in FIG. 5, a method of arranging the strip-shaped separator sheet 4 wound in a roll shape on the upper surface of the positive electrode active material layer 5 while being pressed by the rollers 36 can be mentioned.

On the other hand, as shown in FIG. 5, the strip-shaped negative electrode current collector sheet 8 wound in a roll shape is carried on a support member (not shown) in a predetermined transport direction (horizontal direction from left to right in FIG. 5). As shown in detail in FIG. 6E, a lower wall portion 31b is formed on the peripheral edge of the upper surface of the continuously supplied negative electrode current collector sheet 8. Since the method for forming the lower wall portion 31b is the same as the method for forming the upper wall portion 31a, the description thereof is omitted here.

Next, as shown in FIG. 6 (f), the negative electrode active material and the electrolytic solution forming the negative electrode active material layer 6 are formed in the rectangular space defined by the lower wall portion 31b and the negative electrode current collector sheet 8. Is dropped by the nozzle 38 and filled at least to the height of the lower wall portion 31b, thereby forming a rectangular space defined by the lower wall portion 31b and the negative electrode current collector sheet 8. The negative electrode active material layer 6 is filled and formed.

Then, as shown in FIG. 6 (g), the positive electrode active material layer 5 and the negative electrode active material layer 6 on which the separator 4 is arranged on the upper surface are arranged while being pressurized by the rollers 39. , The roll-shaped cell cell 1 as shown in FIGS. 6 (h) and 7 can be formed. The cell 1 is cut to a predetermined length by using a cutting means such as a cutter 40.

After that, the cell 1 is arranged between the upper container body 21c and the lower container body 21d, and in this state, the inside of the accommodating portion formed by the upper container 21a and the lower container 21b is degassed, and the upper container edge portion 21e and the lower container body 21e By sealing the lower container edge portion 21f with a sealing member, the laminated battery 20 as shown in FIG. 2 can be obtained.

Then, the laminated battery 20 is bent a plurality of times in the longitudinal direction at predetermined intervals, and spacers 23 are arranged between the first surfaces 20b and the second surfaces 20c, respectively, and housed in the frame 22. Therefore, the lithium ion battery L of the present embodiment as shown in FIG. 1 can be manufactured.

Therefore, in the lithium ion battery L of the present embodiment, the thickness of the positive electrode active material layer 5 and the negative electrode active material layer 6 can be made sufficiently thick, so that the battery capacity per unit volume can be increased and a large number of batteries can be used. Since it is not necessary to form the electrode composition layer, it is possible to increase the size at low cost. From the above, according to the present embodiment, it is possible to provide a lithium ion battery and a method for manufacturing the lithium ion battery, which can be increased in size at low cost and can save space while securing an appropriate battery capacity. it can.

In addition, in the lithium ion battery L of the present embodiment, since the spacer 23, which is a support, has a gap S in which gas or liquid can move, the laminated battery 20 is bent to form a limited space. Sufficient heat dissipation due to being housed in 22 can be sufficiently secured, and thereby, space saving and ensuring heat dissipation can be achieved at the same time while securing an appropriate battery capacity.

Further, in the lithium ion battery L of the present embodiment, the electrode terminals 13 and 14 are formed at predetermined intervals on the side of the laminated battery 20, so that even if the laminated battery 20 is long, positive electrode current collection is possible. The electromotive force can be efficiently extracted from the laminated battery 20 without being affected by the resistance of the body 7 and the negative electrode current collector 8 in the length direction.

(Modification example)
The details of the lithium ion battery L of the present invention are not limited to the above-described embodiment, and various modifications are possible. As an example, in the above-described embodiment, the laminated battery 20 is housed in the frame 22 which is a battery container, but as shown in FIG. 8, the battery is also composed of a structural member such as concrete whose sides are open. The lithium-ion battery L may be formed by accommodating the laminated battery 20 and the spacer 23 in the housing 41 which is a container. In this example, as shown in FIG. 9A, after the laminated battery 20 is manufactured by the above-mentioned method, as shown in FIG. 9B, the laminated battery 20 is installed at the installation location of the lithium ion battery L. As shown in FIG. 9C, the spacer 23 may be interposed while bending the laminated battery 20 at the installation location, and the laminated battery 20 and the like may be housed in the housing 41.

Further, in the above-described embodiment, since the support portion 23a of the spacer 23 is formed in a substantially rectangular flat plate shape, as shown in FIG. 11A, the first surface 20b and the second surface 20c facing each other are substantially rectangular. It was supported in a flat plate shape. However, not only the first surface 20b and the second surface 20c are supported in a flat plate shape, but also the support portion of the spacer 23 is formed so as to form a curved surface continuous from the bent portion 20a as shown in FIG. 11 (c). The shape of 23a may be formed.

L Lithium ion battery S void 1 Single cell 2 Positive electrode 3 Negative electrode 4 Separator 5 Positive electrode composition layer 6 Negative electrode composition layer 7 Positive electrode current collector 8 Negative electrode current collector 9 Seal member 13, 14 Electrode terminal 20 Laminated battery 20a Bending Part 20b First surface 20c Second surface 21 Laminated container 22 Frame 23 Spacer 31a Upper wall part 31b Lower wall part 32, 33 Nozzle 34 Vacuum chuck 36 Roller 38 Nozzle 39 Roller 40 Cutter

Claims (6)

Lamination made by sealing a flat battery cell in which a first pole current collector, a first pole active material layer, a separator, a second pole active material layer and a second pole current collector are laminated in this order in a laminating container. In a lithium-ion battery in which the battery is housed in a battery container,
The thickness of the first polar active material layer and the second polar active material layer is 200 μm or more.
The first polar active material layer is a non-binding body of the first polar active material particles, and the second polar active material layer is a non-binding body of the second polar active material particles.
Both the battery cell and the laminated battery have flexibility and
In the laminated battery, the bent portions are formed at predetermined intervals, so that the first surfaces on the first pole current collector side and the second surfaces on the second pole current collector side are formed in the battery container. Multiple folds are made alternately so that they face each other,
The bent portion forms a curved surface continuous with respect to the bending direction of the laminated battery.
At the bent portion, the first pole current collector, the first pole active material layer, the separator, the second pole active material layer, and the second pole current collector are bent.
A lithium ion battery characterized in that the laminated battery is folded so that a predetermined space is formed between the first surfaces and the second surfaces facing each other. In the lithium ion battery according to claim 1,
Lithium is provided between the first surfaces and the second surfaces facing each other, and includes a plurality of supports that support the first surface or the second surface in a predetermined shape. Ion battery. In the lithium ion battery according to claim 2.
The laminated battery is a lithium ion battery characterized by having a plurality of current extraction terminals on its side surface. In the lithium ion battery according to claim 3.
The support is a lithium ion battery characterized by having a gap through which a gas or liquid can move. In the lithium ion battery according to any one of claims 1 to 4.
A lithium ion battery, wherein the first polar active material layer and the second polar active material layer contain an electrode active material having a coating layer containing a polymer compound. Lamination made by sealing a flat battery cell in which a first pole current collector, a first pole active material layer, a separator, a second pole active material layer, and a second pole current collector are laminated in this order in a laminating container. A method for manufacturing a lithium-ion battery in which a battery is housed in a battery container.
The thickness of the first polar active material layer and the second polar active material layer is 200 μm or more.
The first polar active material layer is a non-binding body of the first polar active material particles, and the second polar active material layer is a non-binding body of the second polar active material particles.
Both the battery cell and the laminated battery have flexibility and
By forming bent portions in the laminated battery at predetermined intervals, the first surfaces on the first pole current collector side and the second surfaces on the second pole current collector side are respectively formed in the battery container. The laminated battery is provided with an arrangement step of alternately bending and arranging the laminated batteries so as to face each other.
In the arrangement step, the laminating is performed by bending the first pole current collector, the first pole active material layer, the separator, the second pole active material layer, and the second pole current collector at the bent portion. A step of forming a continuous curved surface with respect to the bending direction of the battery, and a step of arranging a support for supporting the first surface or the second surface between the first surfaces and the second surfaces facing each other. A method for manufacturing a lithium ion battery.

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