JP6823398B2 - battery - Google Patents

Description

The present invention relates to a battery having a stacked battery module formed by stacking a plurality of battery cells.

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 and a negative electrode active material are provided on one surface of a substantially flat current collector constituting the positive electrode and the negative electrode, and then heat treatment is performed to dry the positive electrode active material and the negative electrode active material. Then, if necessary, a separator is sandwiched between the positive electrode active material and the negative electrode active material, and these positive electrode active materials and the negative electrode active material are laminated to produce a substantially flat lithium secondary cell. It was configured as a stacked battery module by stacking multiple layers of next cell cells.

When a lithium-ion battery of a stacked battery module is constructed by stacking multiple layers of lithium secondary batteries, the characteristics of the stacked battery module may fluctuate if the positional relationship between the lithium secondary batteries deviates during use. Therefore, it is preferable to fix the relative positional relationship of these lithium secondary batteries at the time of manufacturing the laminated battery module. Therefore, a technique has been proposed in which a through hole penetrating in the thickness direction of the lithium secondary cell is formed, an electrode terminal is provided in the through hole, and the lithium secondary cell laminated by the electrode terminal is integrated. (See Patent Document 1).

Japanese Unexamined Patent Publication No. 9-259860

However, when the above-mentioned method of forming through holes in the thickness direction of the conventional lithium secondary batteries to fix the relative positional relationship of the laminated lithium secondary batteries is adopted, the positive electrode and negative electrode active materials are used. Is fixed by a binder resin, so when a through hole is formed in the lithium secondary cell by a drill or the like, defects such as cracks and cracks in the positive electrode and negative electrode active material layers may occur, and penetration may occur. There is a problem that it is difficult to fix the relative positional relationship of the lithium secondary batteries to be laminated even if the holes are formed.

The above-mentioned problems are not limited to lithium-ion batteries, but are generally applicable to a laminated battery module in which a plurality of battery cells in which an active material is fixed with a binder are laminated, and a battery using the laminated battery module.

The present invention has been made in view of the above-mentioned problems, and a battery capable of facilitating relative positioning and fixing of stacked battery cells without causing defects in the positive electrode and negative electrode active material layers. Is one of the purposes.

The present invention is a battery having a laminated battery module including a laminated battery cell structure in which a plurality of battery cells are laminated in series, and the battery cell has a positive electrode active material and an electrolytic solution on the surface of a positive electrode current collector. A flat plate-shaped positive electrode on which a positive electrode composition layer containing the above is formed and a flat plate-shaped negative electrode on which a negative electrode composition layer containing a negative electrode active material and an electrolytic solution are formed on the surface of a negative electrode current collector are interposed via a separator. It is laminated. The positive electrode composition layer and the negative electrode composition layer contain a coating active material having a coating layer containing a coating resin on at least a part of the surface of the active material. Then, in the battery cell, a tubular seal member that penetrates the positive and negative current collectors and extends in the thickness direction of the battery cell and has an inner wall as a through hole, and an end face of the seal member. When the first and second engaging portions formed respectively are provided and at least two battery cells are laminated so that the positive and negative current collectors of the respective battery cells are adjacent to each other. Through holes provided in each battery cell are integrally connected, and the first engaging portion and the second engaging portion of one battery cell are engaged with each other, and further, a laminated battery module is provided. At least one of the above-mentioned problems is solved by fixing to the battery outer container by the fastener inserted into the through hole penetrating the laminated battery module and the fixing hole provided in the battery outer container.

The batteries having the above configuration are laminated in a state where the first and second engaging portions formed in the vicinity of the end portions of the through holes are engaged with each other, and are provided in the respective battery cells. The holes are connected together.

Here, the first engagement portion is a projection, it said second engaging portion is concave der Rukoto preferred.

Further, the positive electrode composition layer and the negative electrode composition layer preferably contain conductive fibers, and further, the conductive fibers are preferably carbon fibers.

According to the present invention, it is possible to provide a battery capable of facilitating relative positioning and fixing of stacked battery cells without causing defects in the positive electrode and negative electrode active material layers.

It is a partially broken perspective view which shows the lithium secondary cell which is one Embodiment of this invention. It is a figure which shows the outline of the manufacturing process of the lithium secondary cell of one Embodiment. It is sectional drawing which shows the laminated battery module to which the lithium secondary cell of one Embodiment was applied. It is sectional drawing which shows the lithium ion battery to which the lithium secondary cell of one Embodiment was applied. It is a conceptual diagram which shows the state which the lithium ion battery of one Embodiment is housed in an automobile. It is a perspective view which shows the state which the lithium ion battery of one Embodiment is installed in a house.

(One Embodiment)
A battery cell, a stacked battery module, and a battery to which the stacked battery module is applied according to an embodiment of the present invention will be described with reference to FIGS. 1, 3 and 4.

FIG. 1 is a partially cutaway perspective view showing a lithium secondary battery according to an embodiment of the present invention, and FIG. 3 is a sectional view showing a laminated battery module to which the lithium secondary battery of one embodiment is applied. FIG. 4 is a cross-sectional view showing a lithium ion battery to which the lithium secondary cell of one embodiment is applied.

In these figures, the lithium ion battery L of the present embodiment, which is the battery to which the present invention is applied, has a plurality of substantially flat plate-shaped lithium secondary cell 1s, which are the battery cells to which the present invention is applied, in series. The laminated battery module 20 formed by stacking is housed in a hollow box-shaped battery outer container 21 forming the outer shell of the lithium ion battery L.

Here, in the present invention, the lithium secondary cell is 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 is a battery having a structure in which a negative electrode having a negative electrode composition layer containing the above electrode formed on the surface of a negative electrode current collector is laminated via a separator, and is not provided with a battery container, a terminal arrangement, an electronic control device, or the like. The lithium secondary cell may be abbreviated as a cell.

As shown in detail in FIG. 1, the lithium secondary cell 1 has a substantially flat plate-shaped positive electrode composition layer 5 containing a positive electrode active material and an electrolytic solution on the surface of a substantially rectangular flat plate-shaped positive electrode current collector 7. And the negative electrode 3 in which the substantially flat plate-shaped negative electrode composition layer 6 containing the negative electrode active material and the electrolytic solution is formed on the surface of the substantially rectangular flat plate-shaped negative electrode current collector 8. However, similarly, they are laminated with each other via a substantially flat plate-shaped separator 4, and are formed in a substantially rectangular flat plate shape as a whole. As a result, the lithium secondary 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, the positive electrode composition layer 5 and the negative electrode composition layer 6 are formed in a seal member 9 having a substantially rectangular frame shape extending in the thickness direction of the lithium secondary cell 1. Further, the end portion of the separator 4 is also embedded in the seal member 9. The positive electrode current collector 7 and the negative electrode current collector 8 are provided so as to cover the upper surface of the positive electrode composition layer 5 and the lower surface of the negative electrode composition layer 6 in FIG. 1, respectively, and the seal member 9 is provided. It is provided so as to cover the upper surface and the lower surface.

The positive electrode composition layer 5 and the negative electrode composition layer 6 each contain a coating active material having a coating layer containing a coating resin on at least a part of the surface of the active material.

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 seal member 9, and the separator 4, the positive electrode current collector 7, and the negative electrode current collector 8 are also predetermined by the seal member 9. They are positioned so as to face each other at intervals.

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 collector are adjusted. The positional relationship between the electric body 8 and the separator 4 is determined so that the required spacing can be obtained.

As shown in FIGS. 1 and 3, the lithium secondary cell 1 has a cylindrical sealing member that penetrates the positive electrode 2, the negative electrode 3, and the separator 4 and extends in the thickness direction of the lithium secondary cell 1. 10 is inserted in the stacking direction. Then, a through hole 11 penetrating the positive electrode 2, the negative electrode 3, and the separator 4 is formed by the peripheral wall of the cylindrical seal member 10. As best shown in FIG. 1, the positive electrode current collector 7 (and also the negative electrode current collector 8 (not shown)) has a hole 7a formed in a portion corresponding to the seal member 10. As a result, the upper and lower end surfaces of the seal member 10 in FIGS. 1 and 3 are exposed from the positive electrode and negative electrode current collectors 7 and 8.

Then, in FIGS. 1 and 3 of the seal member 10 which is both ends of the through hole 11, the convex portions 12 and the second engaging portions, which are the first engaging portions that can be engaged with each other, are attached to the upper and lower end surfaces, respectively. The recess 13 is formed. More specifically, the convex portion 12 of the seal member 10 is formed in a cylindrical shape having a smaller diameter than the main body of the seal member 10, and the concave portion 13 of the seal member 10 has substantially the same or slightly smaller diameter as the diameter of the convex portion 12. It is formed in the shape of a cylinder. As a result, as shown in FIG. 3, in a state where the lithium secondary cell 1s are stacked one above the other, the convex portions 12 and the concave portions 13 of the vertically adjacent lithium secondary cell 1s are engaged with each other, and the stacking thereof is performed. The position is positioned. Then, as shown in FIG. 3, the through holes 11 formed in the seal member 10 are connected in the vertical direction to form substantially integrated through holes.

In addition, the four corners 9a of the seal member 9, which correspond to the four corners of the lithium secondary cell 1, are each bulged inward (that is, toward the positive electrode 2 and the negative electrode 3) as shown in FIG. A through hole 14 similar to the through hole 11 is also formed in the corner portion 9a. In the present embodiment, the corner portion 9a of the seal member 9 is formed in a shape forming a part of a cylinder. Further, as best shown in FIG. 1, the positive electrode current collector 7 (and the negative electrode current collector 8 (not shown) also has a notch 7b in a portion corresponding to the corner 9a of the seal member 9. As a result, the upper and lower end surfaces of the corner portion 9a of the seal member 9 are exposed from the positive electrode and negative electrode current collectors 7 and 8 in FIGS. 1 and 3.

Then, in FIG. 1 of the corner portion 9a of the seal member 9, a convex portion 15 which is a first engaging portion and a concave portion 16 which is a second engaging portion are formed on each of the upper and lower end surfaces. Has been done. More specifically, the convex portion 15 and the concave portion 16 of the corner portion 9a of the seal member 9 are formed to have substantially the same shape as the convex portion 12 and the concave portion 13 of the seal member 10 described above, whereby the lithium secondary unit is formed. In a state where the batteries 1 are stacked one above the other, the convex portions 15 and the concave portions 16 of the lithium secondary cell 1s adjacent to each other, and the convex portions 12 and the concave portions 13 are engaged with each other, and the laminated positions thereof are positioned. .. Although not shown, the through holes 14 formed in the corners 9a of the seal member 9 are also connected in the vertical direction to form substantially integrated through holes.

In the present embodiment, the convex portions 12, 15 and the concave portions 13 and 16 provided in one lithium secondary cell 1 are a total of six as shown in FIG. 1, but the number and formation position thereof are limited. Instead, as shown in FIG. 3, an arbitrary number and formation positions can be selected on condition that the stacking positions of the lithium secondary batteries 1 superimposed on the top and bottom are positioned. Preferably, as will be described later, from the viewpoint of integration and heat diffusion of the laminated battery module 20 and the lithium ion battery L, at least one sealing member 10 and a convex portion are positioned so as to penetrate the positive electrode 2, the negative electrode 3 and the separator 4. 12. It is preferable that the recess 13 is formed.

The positive electrode active material particles constituting the positive electrode active material include composite oxides of lithium and a transition metal (for example, LiCoO ₂ , LiNiO ₂ , LiMnO ₂ and LiMn ₂ O ₄ ), and transition metal oxides (for example, MnO ₂ and V). ₂ O ₅ ), transition metal sulfides (eg MoS ₂ and TiS ₂ ) and conductive polymers (eg polyaniline, polypyrrole, polythiophene, polyacetylene, poly-p-phenylene and polycarbazole) and the like.

The negative electrode active material particles constituting the negative electrode active material include graphite, non-graphitizable carbon, amorphous carbon, a fired polymer compound (for example, a calcined phenol resin, furan resin, etc. and carbonized). Coke (eg pitch coke, needle coke and petroleum coke), carbon fibers, conductive polymers (eg polyacetylene and polyquinolin), tin, silicon, and metal alloys (eg lithium-tin alloys, lithium-silicon alloys, lithium) -Aluminum alloys and lithium-aluminum-manganese alloys, etc.), composite oxides of lithium and transition metals (eg, Li ₄ Ti ₅ O _12, etc.) and the like.

In the lithium secondary cell 1 of the present embodiment, the positive electrode composition layer 5 and the negative electrode composition layer 6 have a coating layer containing a coating resin on at least a part of the surfaces of the positive electrode and negative electrode active material particles, respectively. Contains coating active material. Since the coating layer on the surface of the active material can relieve the stress generated when the through holes are formed, defects are formed in the positive electrode composition layer 5 and the negative electrode composition layer 6 which are the positive electrode and negative electrode active material layers. It is possible to provide a through hole for fixing without occurring.

When the surface of the active material particles is coated with the coating resin, the volume change of the electrode is alleviated and the expansion of the electrode can be suppressed.
Examples of the coating resin include vinyl resin, urethane resin, polyester resin, polyamide resin, epoxy resin, polyimide resin, silicone resin, phenol resin, melamine resin, urea resin, aniline resin, ionomer resin, and polycarbonate. From the viewpoint of the liquid absorption property of the electrolytic solution and the processability of the through holes, vinyl resin, urethane resin, polyester resin or polyamide resin is preferable, and the liquid absorption rate when immersed in the electrolytic solution is 10% or more. Some are more preferred.

The liquid absorption rate when immersed in the electrolytic solution is calculated by the following formula by measuring the weight of the coating resin before and after the immersion in the electrolytic solution.
Liquid absorption rate (%) = [(Weight of coating resin after immersion in electrolyte solution-Weight of coating resin before immersion in electrolyte solution) / Weight of coating resin before immersion in electrolyte solution] × 100
The electrolytic solution for determining the liquid absorption rate is preferably a mixed solvent in which ethylene carbonate (EC) and diethyl carbonate (DEC) are mixed in a volume ratio of EC: DEC = 3: 7 and LiPF ₆ as an electrolyte is 1 mol / mol /. An electrolytic solution dissolved so as to have a concentration of L is used.
Immersion in the electrolytic solution for determining the liquid absorption rate is performed at 50 ° C. for 3 days. By immersing at 50 ° C. for 3 days, the polymer compound is in a saturated liquid absorbing state. The saturated liquid absorbing state means a state in which the weight of the coating resin does not increase even if it is further immersed in the electrolytic solution.
The electrolytic solution used in manufacturing the lithium ion battery is not limited to the above electrolytic solution, and other electrolytic solutions may be used.

When the liquid absorption rate is 10% or more, lithium ions can easily permeate the coating resin, so that the ion resistance in the electrode composition layer can be kept low. If the liquid absorption rate is less than 10%, the conductivity of lithium ions becomes low, and the performance as a lithium ion battery may not be sufficiently exhibited.
The liquid absorption rate is preferably 20% or more, and more preferably 30% or more.
The preferred upper limit of the liquid absorption rate is 400%, and the more preferable upper limit is 300%.

It is preferable that the positive electrode composition layer 5 and the negative electrode composition layer 6 each contain a positive electrode active material that is not bound to each other and a negative electrode active material that is not bound to each other. If the active materials are not bound to each other, even if the thickness of the electrode composition layer is increased, the bound state is not destroyed by providing the through holes, and the active material layer is peeled off or cracked. Is preferable.
The coating active material contained in the positive electrode composition layer 5 and the negative electrode composition layer 6 of the present invention is a coating active material in which a part or all of the surface of the active material is coated with a polar coating layer containing a coating resin. Therefore, when the coating active materials come into contact with each other, they are reversibly adhered and fixed, so that the active material can be fixed in the electrode composition without using a binder. In this case, even if the coating active materials come into contact with each other, the coating layers are not irreversibly bonded to each other on the contact surface, and the bonding is temporary and can be easily loosened by hand. In the electrode composition layer containing the coating active material, the active materials are not bonded to each other.

The coating layer contained in the coating active material may further contain a conductive auxiliary agent, and the conductive auxiliary agent is selected from materials having conductivity.

Specifically, metals [aluminum, stainless steel (SUS), silver, gold, copper and titanium, etc.], carbon [graphite and carbon black (acetylene black, ketjen black, furnace black, channel black, thermal lamp black, single layer) Carbon nanotubes, multi-walled carbon nanotubes, etc.), etc.], and mixtures thereof, etc., but are not limited thereto.

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. Further, these conductive auxiliaries may be those obtained by coating a conductive material (a metal one among the above-mentioned conductive auxiliary materials) around a particle-based ceramic material or a resin material by plating or the like.

It is also possible to use conductive fibers as the conductive auxiliary agent. The conductive fibers include carbon fibers (PAN-based carbon fibers, carbon fibers such as pitch-based carbon fibers, etc.), conductive fibers in which highly conductive metals and graphite are uniformly dispersed in synthetic fibers, and stainless steel. Examples thereof include metal fibers obtained by fiberizing metal such as steel, conductive fibers in which the surface of organic fibers is coated with metal, and conductive fibers in which the surface of organic fibers is coated with a resin containing a conductive substance. Among these conductive fibers, carbon fibers are preferable.

The ratio of the total weight of the coating resin and the conductive auxiliary agent contained in the coating layer is preferably 0.1 to 25% by weight based on the weight of the active material, and the weight of the coating resin with respect to the weight of the active material. The ratio of the weight of the conductive auxiliary agent is preferably 0.1 to 20% by weight, and when the conductive auxiliary agent is used, the ratio of the weight of the conductive auxiliary agent to the weight of the active material is preferably 1 to 10% by weight.

For the coating active material, for example, in a state where the active material particles are placed in a universal mixer and stirred at 30 to 500 rpm, a resin solution containing a coating resin is added dropwise over 1 to 90 minutes, and a conductive additive is further mixed. It can be obtained by raising the temperature to 50 to 200 ° C. with stirring, reducing the pressure to 0.007 to 0.04 MPa, and then holding the mixture for 10 to 150 minutes.

The positive electrode composition layer 5 and the negative electrode composition layer 6 each contain a mixture of the active material contained in the coating active material and an electrolytic solution described later or a non-aqueous solvent described later in the positive electrode current collector 7 and the negative electrode current collector 8. It can be obtained by applying it to each surface. The mixture may further contain a binder (polyvinylpyrrolidone, carboxymethyl cellulose, SBR latex, etc.), but the positive electrode composition layer 5 and the negative electrode composition layer 6 are not bound to each other, and the positive electrode active material is bound to each other. Since it is preferable that it contains an uncoated negative electrode active material, it is preferable that it does not contain a binder. When a non-aqueous solvent is used for the mixture, the mixture is applied to the surfaces of the positive electrode current collector 7 and the negative electrode current collector 8, and if necessary, the non-aqueous solvent is dried and removed, and then the electrolytic solution is used. The positive electrode composition layer 5 and the negative electrode composition layer 6 can be obtained by impregnating with.
The thickness of the positive electrode composition layer 5 and the negative electrode composition layer 6 is preferably 100 to 10000 μm.

It is preferable that each of the positive electrode composition layer 5 and the negative electrode composition layer 6 further contains conductive fibers different from the conductive auxiliary agent that the coating layer may have. Conductive fibers, which are different from the conductive auxiliary agents that the coating layer may have, are present on the surface of the coating active material, and can assist in fixing the active material and at the same time reduce the conductivity in the electrode composition. preferable. Examples of the conductive fibers include the same conductive fibers as those exemplified in the above-mentioned conductive auxiliary agent, and preferred ones are also the same.

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

As the electrolyte, those used in the electrolytic solution for lithium ion batteries can be used, for example, lithium salts of inorganic acids such as LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ and LiClO ₄ , LiN (CF ₃ SO). ₂ ) Examples include lithium salts of organic acids such as ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ and LiC (CF ₃ SO ₂ ) ₃ . Of these, LiPF ₆ is preferable from the viewpoint of battery output and charge / discharge cycle characteristics.

As the non-aqueous solvent, those used in the electrolytic solution for lithium ion batteries can be used, and for example, a lactone compound, a cyclic or chain carbonate, a chain carboxylic acid ester, a cyclic or chain ether, or a phosphoric acid ester can be used. , A nitrile compound, an amide compound, a sulfone, a sulfolane and the like, and mixtures thereof can be used.

One type of non-aqueous solvent may be used alone, or two or more types may be used in combination.

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

The separator 4 includes a microporous film film made of polyolefin such as polyethylene and polypropylene, a multilayer film of a porous polyethylene film and polypropylene, a non-woven fabric made of polyester fiber, aramid fiber, glass fiber and the like, and silica on their surfaces. Examples thereof include those to which ceramic fine particles such as alumina and titania are attached.

As the positive electrode and negative electrode current collectors 7 and 8, a metal current collector or a resin current collector can be used. As the metal current collector, a known metal current collector can be used. For example, metal collectors are selected from the group consisting of copper, aluminum, titanium, nickel, tantalum, niobium, hafnium, zirconium, zinc, tungsten, bismuth, antimony, and alloys containing one or more of these, as well as stainless alloys. A current collector consisting of one or more types is preferable. The metal current collector may be formed from a thin plate or a metal foil, or a metal layer may be formed on the surface of a base material by a method such as sputtering, electrodeposition, or coating.

The polymer material constituting the resin current collector may be a conductive polymer or a polymer having no conductivity.

Examples of the 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, or a mixture thereof.

From the viewpoint of electrical stability, polyethylene (PE), polypropylene (PP), polymethylpentene (PMP) and polycycloolefin (PCO) are preferable, and polyethylene (PE), polypropylene (PP) and polymethylpentene are more preferable. (PMP).

Further, the resin current collector has the purpose of improving the conductivity of the resin current collector containing the conductive polymer material, or imparts conductivity to the resin current collector containing the non-conductive polymer material. It is preferable to contain a conductive filler for the purpose of The conductive filler is selected from materials having conductivity. Preferably, from the viewpoint of suppressing ion permeation in the current collector, it is preferable to use a material having no conductivity with respect to ions used as a charge transfer medium. Specific examples thereof include, but are not limited to, carbon materials, aluminum, gold, silver, copper, iron, platinum, chromium, tin, indium, antimonide, titanium, and nickel. These conductive fillers may be used alone or in combination of two or more. Further, these alloy materials such as stainless steel (SUS) may be used. From the viewpoint of corrosion resistance, aluminum, stainless steel, carbon material, nickel, and more preferably carbon material are preferable. Further, these conductive fillers may be a particle-based ceramic material or a resin material coated with the metal shown above by plating or the like.

Specific examples of the resin current collector include those obtained by dispersing 5 to 20 parts of acetylene black as a conductive filler in polypropylene and then rolling it 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 sealing members 9 and 10 is not particularly limited as long as it has adhesiveness to the positive electrode and negative electrode current collectors 7 and 8 and is durable against the electrolytic solution, but is not particularly limited. , Particularly a thermosetting resin is preferable. 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.

In the lithium secondary cell 1 having the above configuration, as shown in FIG. 3, the positive electrode current collector 7 and the negative electrode current collector 8 of the lithium secondary cell 1 adjacent to each other are in contact with each other, and the convex portion 12 is further formed. , 15 and the recesses 13 and 16 are engaged with each other so that the stacking positions are positioned and stacked vertically to form the stacked battery module 20. Then, as shown in FIG. 4, the laminated battery module 20 is housed in the battery outer container 21, and the lithium ion battery L of the present embodiment is configured. In the present embodiment, the battery outer container 21 is formed in a hollow box shape, and is divided into upper and lower parts on the side thereof to form an upper container 21a and a lower container 21b. When the laminated battery module 20 is stored in the battery outer container 21, the upper container 21a and the lower container 21b are separated and the laminated battery module 20 is stored inside, and the upper container 21a and the lower container 21b are stored. Can be reassembled.

A recess 22 is formed on the upper surface of the battery outer container 21 (upper container 21a) at a position corresponding to the through hole 11 of the seal member 10, and a fixing hole 23 is formed at the bottom of the recess 22. .. Similarly, a fixing hole 24 is formed on the lower surface of the container 21 (lower container 21b) at a position corresponding to the through hole 11 of the sealing member 10. Then, the fastener 25 such as a bolt or a screw is inserted into the through hole 11 and the fixing holes 23, 24 of the seal member 10, the head portion 25a of the fastener 25 is housed in the recess 22, and the end portion 25b is lithium. By fastening the ion battery L to the main body H to which the ion battery L is to be attached, the battery outer container 21 is fixed to the main body H, and the laminated battery module 20 housed in the battery outer container 21 is also integrated with the battery outer container 21. It is fixed to the main body H.

In the present embodiment, since the cylindrical spacer 26 having substantially the same height as the laminated battery module 20 is inserted in the through hole 11 of the seal member 10, the fastening force acting by the fastener 25 is increased. It acts on the main body H from the upper container 21a via the spacer 26 via the lower container 21b, and does not act directly on the laminated battery module 20. Therefore, there is an advantage that an excessive force does not act on the laminated battery module 20.

As the material constituting the battery outer container 21, any material can be preferably applied as long as the material can accommodate the laminated battery module 20 in the battery outer container 21. However, considering that the heat generated from the laminated battery module 20 is rapidly diffused and dissipated, a material having high thermal conductivity such as metal is preferable. However, since a short circuit may occur due to direct contact between the laminated battery module 20 and the battery outer container 21, it is preferable to form an insulating layer or the like on the inner surface of the battery outer container 21.

Next, a method for manufacturing the lithium secondary cell 1 having the above configuration will be described with reference to FIG.

First, as shown in FIG. 2A, a pin 30 having a lower portion 30a formed in a columnar shape corresponding to the recess 13 is fitted into the hole 8a of the negative electrode current collector 8 so that the lower portion 30a fits into the hole 8a. In this state, the seal members 9 and 10 are formed on the upper surface of the negative electrode current collector 8 in the drawing. The method of forming the seal members 9 and 10 on the upper surface of the negative electrode current collector 8 is arbitrary, but as an example, a mechanism such as an inkjet machine or a 3D printer that can control the movement of the nozzle to a predetermined location to eject a predetermined amount of members. A method of discharging the members forming the seal members 9 and 10 is preferably mentioned.

Next, as shown in FIG. 2B, when the sealing members 9 and 10 are formed to a height at which the negative electrode composition layer 6 should be formed, the negative electrode composition 6 containing the negative electrode active material and the electrolytic solution is formed. It is formed on the upper surface of the negative electrode current collector 8 to form the negative electrode 3. The method of forming the negative electrode 3 is arbitrary, and the negative electrode composition 6 is applied to each surface of the negative electrode current collector 8, and the negative electrode composition is applied to each surface of the negative electrode current collector 8 via a nozzle or the like. Various methods can be mentioned, such as placing 6 on the plate and then leveling it with a spatula or the like so as to have a predetermined thickness.

Next, as shown in FIG. 2C, the separator 4 is placed so as to cover the upper surface of the negative electrode composition 6 forming the negative electrode 3 in the drawing and to place the end portion on the end portion of the seal member 9. Place. Here, a hole 4a is formed in the separator 4, and the separator 4 is placed on the upper surface of the negative electrode composition 6 so that the upper end portion 30b of the pin 30 penetrates the hole 4a. The method of placing the separator 4 on the upper surface of the negative electrode composition 6 is arbitrary. As an example, the upper surface of the separator 4 is held by a vacuum chuck 31, and the separator 4 is mounted on the negative electrode composition 6 by using the vacuum chuck 31. A method of removing the chuck 31 from the separator 4 after placing the chuck 31 on the upper surface of the separator 4 is preferably used.

Next, as shown in FIG. 2D, the sealing members 9 and 10 are formed on the upper surface of the separator 4 in the drawing, and the sealing members 9 and 10 are formed to a height at which the positive electrode composition layer 5 should be formed. As shown in FIG. 2E, the positive electrode composition 5 containing the positive electrode active material and the electrolytic solution is formed on the upper surface of the separator 4 to form the positive electrode 2. Since the method of forming the positive electrode 2 is substantially the same as the method of forming the negative electrode 3, the description thereof will be omitted here.

Next, as shown in FIG. 2 (f), the positive electrode current collector covers the upper surface of the positive electrode composition 5 forming the positive electrode 2 in the drawing, and the end portion is placed on the end portion of the seal member 9. Place 7 on it. Since the hole 7a is formed in the positive electrode current collector 7 as described above, the positive electrode current collector 7 is placed on the upper surface of the positive electrode composition 5 so that the upper end portion 30b of the pin 30 penetrates the hole 7a. Be placed. Since the method of placing the positive electrode current collector 7 on the upper surface of the positive electrode composition 5 is substantially the same as the method of placing the separator 4 on the upper surface of the negative electrode composition 6, the description thereof will be omitted here.

Next, as shown in FIG. 2 (g), a mold in which a concave portion 32a having a shape corresponding to the convex portion 12 is formed on the lower surface and a through hole 32b into which the upper end portion 30b of the pin 30 can be inserted is formed in the central portion. The pushing member 32 is pressed against the upper surface of the sealing member 10 to form a convex portion 12 on the upper surface of the sealing member 10, and then the pin 30 and the embossing member 32 are removed as shown in FIG. 2 (h). Therefore, the lithium secondary cell 1 shown in FIG. 1 can be manufactured.

As an example, the lithium ion battery L of the present embodiment is housed in the lower part of the seat 41 of the automobile 40 as shown in FIG. 5, or as shown in FIG. 6, the structure panel constituting the wall surface 43 of the house 42. As a part of the structure constituting the house 42, it is attached by the fastener 44. In the example shown in FIG. 5, the heat generated from the lithium ion battery L is rapidly transmitted to the structure (frame or the like) of the automobile 40 to dissipate heat. Further, in the example shown in FIG. 6, the lithium ion battery L can be installed also as the structure of the house 42, a large capacity power source can be secured in the house 42, and the installation space can be reduced. Can be planned.

Therefore, according to the lithium secondary cell 1 of the present embodiment, the convex portions 12, 15 and the concave portions 13 and 16 are engaged with each other to position the laminated positions of the lithium secondary cell 1s adjacent to each other. It can be done easily. Thereby, it is possible to realize the lithium secondary cell 1 and the lithium ion battery L which can facilitate the relative positioning and fixing of the lithium secondary cell 1 in the laminated state.

Further, according to the lithium secondary cell 1 of the present embodiment, the structure in which the convex portions 12, 15 and the concave portions 13 and 16 are engaged with each other can prevent the positional deviation with time. As a result, it is possible to realize the lithium secondary cell 1 and the lithium ion battery L that can maintain stable performance for a long period of time even in an application that receives vibration for a long period of time such as an electric vehicle.

The details of the battery cell, the laminated battery module, and the battery 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, a plurality of lithium secondary cells 1 are stacked to form a laminated battery module 20, and the laminated battery module 20 is housed in a battery outer container 21 to form a lithium ion battery L. Although it has been configured, the present invention can be suitably applied to a battery cell other than the lithium secondary cell 1 and a battery using this battery cell.

L Lithium-ion battery 1 Lithium secondary cell (battery cell)
2 Positive electrode 3 Negative electrode 4 Separator 5 Positive electrode composition 6 Negative electrode composition 7 Positive electrode current collector 8 Negative electrode current collector 9, 10 Sealing members 11, 14 Through holes 12, 15 Convex parts 13, 16 Concave parts 20 Laminated battery module 21 Battery outer container

Claims (4)

A battery having a laminated battery module including a laminated battery cell structure in which a plurality of battery cells are laminated in series.
The battery cell is
A flat 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 containing a negative electrode active material and an electrolytic solution on the surface of a negative electrode current collector. The flat negative electrode on which the composition layer is formed is laminated via the separator.
The positive electrode composition layer and the negative electrode composition layer contain a coating active material having a coating layer containing a coating resin on at least a part of the surface of the active material.
Further, the battery cell is
A tubular seal member that penetrates the positive electrode current collector and the negative electrode current collector and extends in the thickness direction of the battery cell and has an inner wall as a through hole.
A first and second engaging portions formed on the end faces of the sealing member are provided.
When at least two of the battery cells are laminated so that the positive electrode current collector and the negative electrode current collector of the respective battery cells are adjacent to each other, the through holes provided in the respective battery cells are formed. The first engaging portion of one of the battery cells and the second engaging portion of the other battery cell are integrally connected to each other, and further, the second engaging portion of the battery cell is engaged with each other.
A battery characterized in that the laminated battery module is fixed to the battery outer container by a fastener inserted into the through hole penetrating the laminated battery module and a fixing hole provided in the battery outer container. In the battery according to claim 1,
It said first engagement portion is a projection, battery and the second engaging portion and said recess der Rukoto. In the battery according to claim 1 or 2.
A battery characterized in that the positive electrode composition layer and the negative electrode composition layer further contain conductive fibers. In the battery according to claim 3,
A battery characterized in that the conductive fiber is a carbon fiber.

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