JP6817840B2 - Lithium ion battery - Google Patents

Description

The present invention has a power generation unit including a cell in which 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 are laminated in this order, and a battery outer container accommodating the power generation unit. Regarding lithium-ion batteries.

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 active material layer containing a positive electrode active material, a binder resin and an electrolytic solution and a negative electrode active material layer containing a negative electrode active material, a binder resin and an electrolytic solution are laminated with a separator in between. It is configured to be stored in a container in a state of being (see, for example, Patent Document 1).

In recent years, with the growing awareness of recycling, it is considered to carry out the work of used lithium-ion batteries that can be reused and recycled by separating the positive electrode active material layer, negative electrode active material layer, separator and container after collection. The above-mentioned Patent Document 1 also discloses a technique in which an insulating member is attached to an end portion of an electrode plate in order to prevent a short circuit between a positive electrode and a negative electrode during sorting.

Japanese Unexamined Patent Publication No. 2006-324118 Japanese Unexamined Patent Publication No. 2013-45760

However, in the conventional lithium ion battery described above, the positive electrode active material layer and the negative electrode active material layer contain a binder resin, and the positive electrode active material layer and the negative electrode active material layer are solidified by the binder resin. Even if the lithium ion battery is recovered and used in the recycling process, the positive electrode active material layer, the negative electrode active material layer, the separator and the container can be separated, but it is difficult to reuse these the positive electrode active material layer and the negative electrode active material layer. Met.

Although a technique for taking out and regenerating an electrode group in an alkaline storage battery, particularly a nickel-cadmium battery, has been proposed (see Patent Document 2), the positive electrode active material layer and the negative electrode active material layer are easily reused in the lithium ion battery. The technology has not yet been proposed.

The present invention has been made in view of the above-mentioned problems, and one of its objects is to provide a lithium ion battery capable of easily reusing a positive electrode active material layer and a negative electrode active material layer in a recycling process. It is said.

The present invention includes a power generation unit including a cell in which 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 are laminated in this order, and a battery outer container that houses and seals the power generation unit. It is applied to the lithium-ion battery. Then, a protruding portion that protrudes from the main body of the positive electrode current collector and / or the negative electrode current collector and protrudes outward from the end portion of the battery outer container and an end portion of the battery outer container are formed to form the positive electrode current collector and / or the negative electrode current collector. / Or provided at a position where a crack is generated between a part of the battery outer container that overlaps the protruding portion and the remaining battery outer container when the protruding portion is moved in the direction of separating the negative electrode current collector from the power generating portion. The positive electrode active material layer is a non-bonded body of positive electrode active material particles, the negative electrode active material layer is a non-bonded body of negative electrode active material particles, and a part of the battery outer container is provided with a groove portion . At least one of the above-mentioned problems is solved by providing an open portion that exposes the positive electrode active material layer and / or the negative electrode active material layer by being configured to be openable.

The positive electrode active material layer is a non-bonded body of positive electrode active material particles, and the negative electrode active material layer is a non-bound body of negative electrode active material particles, both of which are solidified by a binder resin like a conventional lithium ion battery. Not. A part of the battery outer container is provided with an open portion that exposes the positive electrode active material layer and / or the negative electrode active material layer by being configured to be openable. Therefore, by opening this open portion, , The positive electrode active material layer and / or the negative electrode active material layer can be taken out.

Here, it is preferable that the groove extends along the protruding portion of the main body of the positive electrode current collector and / or the negative electrode current collector to the inner edge of the battery outer container.

Further, the positive electrode active material layer contains coated positive electrode active material particles in which at least a part of the surface of the positive electrode active material particles is coated with a coating agent containing a conductive auxiliary agent and a coating resin, and the negative electrode active material layer. However, it is preferable to include coated negative electrode active material particles in which at least a part of the surface of the negative electrode active material particles is coated with a layer containing a coating resin.

According to the present invention, it is possible to provide a lithium ion battery capable of easily reusing the positive electrode active material layer and the negative electrode active material layer in the recycling process.

It is sectional drawing which shows the lithium ion battery which is one Embodiment of this invention. It is a perspective view which shows the lithium ion battery which is one Embodiment. It is a perspective view which shows the open part of the lithium ion battery of one Embodiment. It is a perspective view which shows the process of opening the open part of the lithium ion battery of one Embodiment. It is a perspective view which shows the state which the open part of the lithium ion battery of one Embodiment is opened. It is a figure which shows the recycling process using the lithium ion battery which is one Embodiment. It is a process drawing which shows the recycling process using the lithium ion battery which is one Embodiment. It is sectional drawing which shows the groove part of the lithium ion battery which is one Embodiment.

(One Embodiment)
A lithium ion battery according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a sectional view showing a lithium ion battery according to an embodiment of the present invention, FIG. 2 is a perspective view showing a lithium ion battery according to an embodiment, and FIG. 3 shows an open portion of the lithium ion battery according to the embodiment. It is a perspective view.

The battery outer container (hereinafter, simply referred to as “container”) 20, which is the outer body of the lithium ion battery L of the present embodiment, has sheet-shaped members formed into predetermined shapes, as shown in detail in FIGS. 1 and 2. It is divided into an upper container 20a and a lower container 20b. The upper container 20a and the lower container 20b are formed in substantially the same shape, and the upper container body 20c and the lower container body 20d, and a pair of upper containers protruding to the left and right in FIG. 1 of the upper container body 20c and the lower container body 20d. The container 20 is provided with a container edge portion 20e and a lower container edge portion 20f, and the pair of upper container edge portions 20e and the lower container edge portion 20f are overlapped and sealed so that the container 20 has a positive current collector and a positive positive active material layer. A power generation unit including a cellar in which a separator, a negative electrode active material layer, and a negative electrode current collector are laminated in this order can be accommodated and sealed.

A positive electrode current collector 7 and a negative electrode current collector 8 are formed on the inner surfaces of the upper container 20a and the lower container 20b (the lower surface of the upper container 20a and the upper surface of the lower container 20b in FIG. 1), that is, the inner surface of the container 20. There is. The positive electrode current collector 7 and the negative electrode current collector 8 have main body portions 7a and 8a formed in a substantially rectangular plate shape that substantially covers the lower surface of the upper container main body 20c and the upper surface of the lower container main body 20d in FIG. It includes protruding portions 7b and 8b that protrude from the portions 7a and 8a and extend between the upper container edge portion 20e and the lower container edge portion 20f and project outward from the end portion of the container 20. The protruding portions 7b and 8b function as electrode terminals for extracting the electromotive force of the lithium ion battery L to the outside. In the present embodiment, the main body portions 7a and 8a and the protruding portions 7b and 8b are manufactured as an integral member, but the main body portion and the protruding portion are manufactured separately and the positive electrode is integrated by adhering or the like. The current collector 7 and the negative electrode current collector 8 may be manufactured.

A substantially flat plate-shaped separator 4 is arranged between the upper container 20a and the lower container 20b, and the hollow space between the upper container 20a and the lower container 20b is divided into a positive electrode chamber 2 and a negative electrode chamber 3, respectively. .. The positive electrode chamber 2 and the negative electrode chamber 3 are filled with the positive electrode active material layer 5 and the negative electrode active material layer 6, respectively, whereby the positive electrode current collector 7, the positive electrode active material layer 5, the separator 4, and the negative electrode active material layer are filled. A power generation unit including a cell 1 in which 6 and a negative electrode current collector 8 are laminated in this order is configured. Then, the cell 1 is housed by the upper container 20a and the lower container 20b, and the space between the upper container edge 20e and the lower container edge 20f is sealed by a sealing member (not shown), whereby the lithium ion of the present embodiment is sealed. The battery L is formed.

As shown in details in FIGS. 4 and 5, a part of the container 20 of the lithium ion battery L of the present embodiment is configured to be openable so that the positive electrode active material layer 5 and / or the negative electrode active material layer 6 can be opened. An opening portion 10 is provided to expose the surface.

As shown in detail in FIGS. 2 and 3, the lithium ion battery L of the present embodiment protrudes from the main body of the positive electrode current collector 7 and / or the negative electrode current collector 8 and outwards from the end of the container 20. It has a protruding portion that protrudes from the surface. More specifically, the upper container edge 20e and / or a part of the current collectors protruding from the main bodies 7a and 8a of the positive electrode current collector 7 and / or the negative electrode current collector 8 and which is the end of the container 20. Alternatively, it has protruding portions 7b and 8b protruding outward from the outer edge of the lower container edge portion 20f. Further, the positive electrode current collector 7 is formed at the end of the container 20 provided with the protrusions 7b and 8b, and the protrusions 7b and 8b are formed together with a part of the edge of the container 20 overlapping the protrusions 7b and 8b. And / or a part of the container 20 and the remaining container 20 that overlap the protrusions 7b and 8b when the negative electrode current collector 8 and the cell 1 are moved in a direction away from each other (upward in FIGS. 2 and 3). It is provided with a groove portion 11 provided at a position where a crack is generated between the two. The groove 11 is formed from the outer edge of the upper container edge 20e and / or the lower container edge 20f of the container 20 to the upper container edge along the protrusions 7b and 8b of the positive electrode current collector 7 and / or the negative electrode current collector 8. It is preferable that the portions 20e and / or the lower container edge portion 20f extend to the inner edge, and along the peripheral edges of the protruding portions 7b and 8b of the positive electrode current collector 7 and / or the negative electrode current collector 8 and the main body portions 7a and 8a. It is more preferable that the container 20a and / or the lower container 20b is extended to the inner surface.

As best shown in FIG. 3, the groove 11 in the lithium ion battery L of the present embodiment is above or below the protruding portions 7b and 8b of the positive electrode current collector 7 and the negative electrode current collector 8 (in the example shown in FIG. 3). It is formed on the upper container edge 20e or the lower container edge 20f located at the upper side), and the upper container body 20c is formed from the end of the upper container edge 20e or the lower container edge 20f at both left and right ends in the drawing of the protrusions 7b and 8b. Alternatively, a pair of notches 11a formed by notching the upper container edge 20e or the lower container edge 20f toward the lower container main body 20d, and the left and right protruding portions 7b and 8b are continuously formed in the notches 11a. It is provided with a pair of cut groove portions 11b extending along both ends (see FIG. 8).

In the present embodiment, the groove portion 11 formed at the end of the container 20 provided with the protruding portions 7b and 8b of the positive electrode current collector 7 and the negative electrode current collector 8 is the upper container edge 20e and the lower container. More specifically, the protruding portion 7b is formed only on the upper container edge portion 20e, and the protruding portion 8b is formed only on the lower container edge portion 20f. In other words, the groove portion 11 is formed on the upper container edge portion 20e or the lower container edge portion 20f on the side in contact with the protruding portions 7b and 8b extending from the main body portions 7a and 8a of the positive electrode current collector 7 and the negative electrode current collector 8. Has been done.

As a result, the protruding portions 7b and 8b are pulled up in the directions indicated by the arrows in FIGS. 3 and 4, in other words, the upper container edge portion 20e or the lower container edge portion of the portion sandwiched between the pair of cutout portions 11a and the cut groove portion 11b. When the protrusions 7b and 8b are moved in the direction of separating the 20f from the other upper container edge 20e or the lower container edge 20f, the upper container edge of the portion sandwiched between the pair of notches 11a and the cut groove 11b. A crack is formed between the portion 20e or the lower container edge 20f and the other upper container edge 20e or the lower container edge 20f, and as shown in FIG. 5, the positive current collector 7 or the negative negative current collector 8 and A part of the upper container 20a or the lower container 20b is separated from the container 20, and as a result, the positive electrode active material layer 5 or the negative negative material active material filled in the positive electrode chamber 2 and the negative electrode chamber by the open portion 10 provided in the container 20. The layer 6 can be exposed to the outside.

Here, in the present specification, “filled” means that the positive electrode active material layer 5 containing the positive electrode active material particles is in the positive electrode chamber 2, and the negative electrode active material layer 6 containing the negative electrode active material particles is in the negative electrode chamber 3, respectively. It means a state in which the positive electrode active material particles and the electrolytic solution are stored in the positive electrode chamber 2, and preferably, the negative electrode active material particles and the electrolytic solution are stored in the negative electrode chamber 3, respectively. It is preferable that the active material particles and the negative electrode active material particles are each mixed with the electrolytic solution.

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 by 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 of being movable in response to an external force, respectively, and are non-bonded positive electrode active material layers 5 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.

It is preferable that the positive electrode active material layer 5 and the negative electrode active material layer 6 which are non-bonded bodies have fluid properties. The property having fluidity means a property in which the active material particles move and the entire shape changes freely by applying an external force such as a powder, slurry, or suspension, and the positive electrode active material particles and When the negative electrode active material particles are mixed with the electrolytic solution, gel-like, slurry-like, powder-like or similar properties are included by adjusting the mixed weight ratio thereof.

In the present invention, in order to fill the positive electrode chamber 2 and the negative electrode chamber 3 with the positive electrode active material layer 5 or the negative electrode active material layer 6, respectively, the active material particles (positive electrode active material particles or negative electrode active material particles) are used as an electrolytic solution. The positive electrode active material layer 5 and the negative electrode active material layer 6 obtained by molding the positive electrode composition or the negative electrode composition obtained by mixing with may be arranged in the positive electrode chamber 2 and the negative electrode chamber 3, respectively. The composition and the negative electrode electrode composition may be directly put into the positive electrode chamber 2 or the negative electrode chamber 3, or the powdery positive electrode active material particles and the negative electrode active material particles may be directly put into the positive electrode chamber 2 and the negative electrode chamber 3, respectively. Good.

When the powdery positive electrode active material particles and the negative electrode active material particles are directly put into the positive electrode chamber 2 and the negative electrode chamber 3, it is preferable to put the electrolytic solution after that.

When the positive electrode composition and the negative electrode composition are formed into the positive electrode active material layer 5 and the negative electrode active material layer 6, the positive electrode electrode composition and the negative electrode composition are respectively predetermined on a sheet-shaped base material without using a binder. By applying the coating to the thickness of the above and removing the non-aqueous solvent, the active materials can be formed into the positive electrode active material layer 5 and the negative electrode active material layer 6 without being bound to each other.

Further, when the positive electrode composition or the negative electrode composition is put into the positive electrode chamber 2 and the negative electrode chamber 3, and when the powdery positive electrode active material particles and the negative electrode active material particles are put in, the container 20 is subjected to vibration or impact. It is preferable that the positive electrode active material particles and the negative electrode active material particles can be uniformly filled in the positive electrode chamber 2 and the negative electrode chamber 3.

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 for 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, a polymer compound fired body (for example, phenol resin, furan resin, etc.) is fired. 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 the positive electrode active material.

The positive electrode active material particles and the negative electrode active material particles may be coated positive electrode active material particles and coated negative electrode 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, respectively. More preferably, the positive electrode active material particles are coated positive electrode 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 coated active material particles are preferable because the flexibility of the positive electrode active material layer 5 and the negative electrode active material layer 6 is good. Further, it is preferable because it is considered that the electrochemical reaction between the electrolytic solution and the active material generated during charging / discharging can be suppressed, the deterioration of the electrolytic solution can be suppressed, and the cycle characteristics are improved. Further, it is preferable that the positive electrode active material particles are coated with a coating layer made of a coating agent containing a coating resin and a conductive auxiliary agent because the electron conductivity of the positive electrode active material layer 5 is further improved. The coating layer of the coated negative electrode active material particles may or may not contain a conductive auxiliary agent. In particular, the negative electrode active material particles include graphite, non-graphitizable carbon, amorphous carbon, and a fired polymer compound. When coke and carbon fiber are used, the negative electrode active material layer 6 has good electron conductivity even if the coating agent does not contain the conductive auxiliary agent, but the negative electrode active material layer 6 is coated with the coating agent and contains the conductive auxiliary agent. The electron conductivity of the material layer 6 may be adjusted.

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 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 vinyl monomer (a2) to be used as an essential constituent monomer.
CH ₂ = C (R ¹ ) COOR ² (1)
[In 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 vinyl group-containing monocarboxylic acid [(meth) acrylic acid, crotonic acid, itaconic acid, etc.], vinyl group-containing dicarboxylic acid [(anhydrous) maleic acid, etc.]. Fumaric acid, (anhydrous) itaconic acid, citraconic acid, mesaconic acid, etc.] and the like, 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.

As the constituent monomers 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 , Butylstyrene, phenylstyrene, cyclohexylstyrene, benzylstyrene, etc.

(A35) Vinyl ester: vinyl acetate, vinyl propionate, vinyl butyrate, diallyl adipate, isopropenyl acetate, vinyl methoxy acetate, vinyl benzoate, diallyl phthalate, methyl-4-vinyl benzoate, 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, diaryloxyethane, 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 content 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) is the constituent unit amount 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 preferably 0.01 to 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. It is preferably 5 to 900% based on the 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 monomers contained in the solution or dispersion is preferably 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 preferably 2% by weight or less based on the total weight of the constituent monomers.

The temperature in the system in the polymerization reaction is preferably −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 preferably 5% by weight or less based on the total weight of the constituent monomers 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 auxiliaries 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 aggregate, or a combination thereof can be used. Among them, from the viewpoint of conductivity and the like. 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.

When the coating agent contains the coating resin and the conductive auxiliary agent, the weight ratio of the coating resin and the conductive auxiliary agent contained in the coating agent is preferably coating resin: conductive auxiliary agent = 100: 1 to 100: 200. More preferably, it is 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 put into the positive electrode chamber 2 and the negative electrode chamber 3, 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 respectively used as an electrolytic solution or an electrolytic solution. It is preferably a mixture obtained by mixing with a non-aqueous solvent, 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, can be used such as those used in the known 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 known electrolytic solutions can be used, such as lactone, cyclic or chain carbonate, chain carboxylic acid ester, cyclic or chain ether, phosphoric acid ester, nitrile compound, and amide. 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 of them 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. Esters, more preferably cyclic carbonates, and mixed solutions of cyclic carbonates and chained carbonates. Particularly preferred are propylene carbonate (PC) and a mixture of propylene carbonate (PC) and ethylene carbonate (EC) and / or 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, the positive electrode chamber 2 and the negative electrode chamber 3 each contain positive electrode active material particles, a fibrous conductive filler, and an electrolytic solution. It is preferable to fill the negative electrode composition containing the composition, 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 is preferably 5 to 100 μm in a single layer or a multilayer, and more preferably 10 to 50 μm. Is.

The maximum pore diameter of the separator 4 made of the porous film or the multilayer film thereof is preferably 1 μm or less. 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 current collector, a metal current 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 base material of the metal current collector may be in the form of a thin plate, a metal foil, or a mesh, 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, or coating. May be formed.

The resin current collector is a current collector formed of a conductive polymer material or a non-conductive polymer material to which conductivity is imparted.

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.

Examples of the non-conductive polymer material include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polycycloolefin (PCO), polyethylene terephthalate (PET), polyether nitrile (PEN), and polytetrafluoroethylene. (PTFE), styrene butadiene rubber (SBR), polyacrylonitrile (PAN), polymethylacrylate (PMA), polymethylmethacrylate (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).

A polymer obtained by imparting conductivity to a non-conductive polymer material can be obtained by mixing a non-conductive polymer material and a conductive filler, and the conductive filler is obtained from a 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, carbon material or nickel is preferable, and a filler obtained from 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 particulate, fibrous, 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 mixture, the mixture is rolled with a hot press. Further, the thickness thereof is not particularly limited, and the same as known ones or appropriately modified ones can be applied.

The material constituting the seal member 9 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 used. Preferably, a thermosetting polymeric material is 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 9 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 surfaces 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 20 obtained by sealing the upper container edge portion 20e and the lower container edge portion 20f with the sealing member 9 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 the like. A cell 1 in which the negative electrode current collectors 8 are stacked in this order is housed as a power generation unit.

As the container 20, any container 20 can be applied as long as it is a container 20 made of a material capable of stably storing the positive electrode composition and the negative electrode composition in the container 20, and in particular, a battery outer container. 20 is preferably flexible. In addition, the container 20 is preferably made of a material having an insulating property in consideration of the possibility of contact between the electrode composition and the container 20, 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) with the power generation unit in which the material and the negative electrode current collector are laminated in order while being housed inside.

As such a container 20, a container made of a laminated film is preferable. 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 20 is coated with a heat-resistant resin (polyethylene resin, polyester resin, etc.) and becomes the inner surface of the container 20. A film coated with a thermoplastic resin (polyethylene, polypropylene, etc.) on the second surface can be raised.

Next, the method for recycling the lithium ion battery of the present embodiment will be described with reference to FIGS. 6 and 7.

First, in the lithium ion battery L of the present embodiment shown in FIG. 7A, as described above, the protruding portion 7b of the positive electrode current collector 7 is pulled up in the direction of the arrow in FIG. 7B by pulling it up. The positive electrode active material layer 5 is exposed to the outside (see FIGS. 3 to 5).

Next, as shown in FIGS. 6 and 7 (c), an electrolytic solution having a composition equivalent to that of water or the electrolytic solution constituting the positive electrode active material layer 5 is applied to the positive electrode active material layer 5 by using a shower nozzle 30 or the like. The poured and slurried positive electrode active material layer 5 is recovered in the recovery container 31.

Next, as shown in FIG. 7 (d), the negative electrode current collector 8 is positioned so as to be upward in the figure, and then, as shown in FIG. 7 (e), the protruding portion of the negative electrode current collector 8. By pulling up 8b in the direction of the arrow in FIG. 7 (e), the negative electrode active material layer 6 is exposed to the outside.

Then, as shown in FIG. 7 (f), water or an electrolytic solution having the same composition as the electrolytic solution constituting the negative electrode active material layer 6 is poured into the negative electrode active material layer 6 using a shower nozzle 30 or the like, and a solution is used. Alternatively, the slurryed negative electrode active material layer 6 is recovered in the recovery container 32.

As a result, the positive electrode active material layer 5 and the negative electrode active material layer 6 can be collected in the collection containers 31 and 32, respectively, and the container 20 and the separator 4 can be separately collected.

Therefore, in the lithium ion battery L of the present embodiment, since the positive electrode active material 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 open portion 10 is used. If the positive electrode active material layer 5 and the negative electrode active material layer 6 are exposed to the outside, the positive electrode active material layer 5 and the negative electrode active material layer 6 can be easily separated and recovered. Moreover, since the positive electrode active material layer 5 and the negative electrode active material layer 6 can be recovered only by pouring water or the like into the positive electrode active material layer 5 and the negative electrode active material layer 6, it affects the separator 4 made of a thin film. For example, the separator 4 is not torn during recovery, so that the separate recovery step of the separator 4 can be facilitated. As a result, according to the lithium ion battery L of the present embodiment, it is possible to realize a lithium ion battery capable of easily reusing the positive electrode active material layer 5 and the negative electrode active material layer 6 in the recycling process.

(Modification example)
The details of the lithium ion battery of the present invention are not limited to the above-described embodiments, and various modifications are possible. As an example, the outer shape of the lithium ion battery of the present invention is not limited to that of the lithium ion battery as shown in FIG. 2, and various outer shapes can be adopted.

L Lithium-ion battery 1 Single battery 2 Positive electrode chamber 3 Negative electrode chamber 4 Separator 5 Positive electrode active material layer 6 Negative electrode active material layer 7 Positive electrode current collector 8 Negative electrode current collector 7a, 8a Main body 7b, 8b Protruding part 9 Seal member 10 Open Part 11 Groove part 11a Notch part 11b Cut groove part 20 Container 20e Upper container edge 20f Lower container edge

Claims (3)

Lithium having a power generation unit including a cell in which 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 are laminated in this order, and a battery outer container that houses and seals the power generation unit. It ’s an ion battery,
A protruding portion that protrudes from the main body of the positive electrode current collector and / or the negative electrode current collector and protrudes outward from the end of the battery outer container.
The battery formed at the end of the battery outer container and overlapping the protruding portion when the protruding portion is moved in a direction in which the positive electrode current collector and / or the negative electrode current collector is separated from the power generation portion. It is provided with a groove provided at a position where a crack is generated between a part of the outer container and the remaining battery outer container.
The positive electrode active material layer is a non-bonded body of positive electrode active material particles, and the negative electrode active material layer is a non-bound body of negative electrode active material particles.
A lithium ion battery in which a part of the battery outer container is provided with an open portion that is configured to be openable so as to expose the positive electrode active material layer and / or the negative electrode active material layer. In the lithium ion battery according to claim 1 ,
The groove portion is a lithium ion battery extending along the protruding portion of the main body portion of the positive electrode current collector and / or the negative electrode current collector to the inner edge of the battery outer container. In the lithium ion battery according to claim 1 or 2 .
The positive electrode active material layer contains coated positive electrode active material particles in which at least a part of the surface of the positive electrode active material particles is coated with a coating agent containing a conductive auxiliary agent and a coating resin.
A lithium ion battery in which the negative electrode active material layer contains coated negative electrode active material particles in which at least a part of the surface of the negative electrode active material particles is coated with a layer containing a coating resin.

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