JP6738706B2 - Lithium ion battery - Google Patents

Description

The invention relates first electrode collector, the first active material layer, the separator, the lithium ion battery second active material layer and the second electrode current collector are stacked in this order.

BACKGROUND ART Lithium-ion (secondary) batteries have been widely used in various applications in recent years as high-capacity, small-sized and lightweight secondary batteries. A general lithium-ion battery includes 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 composition layer containing a negative electrode active material and an electrolytic solution. A unit cell formed by stacking a negative electrode formed on the surface of a negative electrode current collector with a separator interposed therebetween is housed in a container as an outer package.

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

Japanese Patent Publication No. 2015-524994

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

For the purpose of increasing the battery capacity, a lithium ion battery has been proposed in which a positive electrode and a negative electrode having a substantially rectangular parallelepiped shape are alternately projected from a pair of electrode buses extending in one direction and facing each other, and a separator is disposed between the positive electrode and the negative electrode. (See Patent Document 1). However, the lithium-ion battery proposed in Patent Document 1 also has a film thickness of several hundreds of μm, so in order to increase the size, the lithium-ion battery is arranged in a direction orthogonal to the above-mentioned one direction. Therefore, the above-mentioned problems have not been solved yet.

The present invention has been made in view of the above-mentioned problems, and one of the objects thereof is to provide a lithium ion battery that can be made large at low cost and that can secure an appropriate battery capacity. ..

INDUSTRIAL APPLICABILITY The present invention is applied to a lithium ion battery in which a first electrode current collector, a first electrode active material layer, a separator, a second electrode active material layer, and a second electrode current collector are sequentially stacked. A plurality of first pole current collectors and a plurality of second pole current collectors are periodically formed along the first direction at predetermined intervals and project in a second direction different from the first direction. A corrugated current collector having a wave-shaped cross section having a mountain portion, and a plurality of mountain portions each of which the first pole current collector and the second pole current collector have are alternately arranged with the mountain portions facing each other through a separator. And in parallel with each other at a predetermined interval along the first direction, and in each of the cross sections of the first pole current collector and the second pole current collector, to the side surface of the mountain portion and the side surface of the mountain portion adjacent thereto. The ratio (ΔL:Lh) between the maximum distance (ΔL) and the shortest distance (Lh) from the top of the mountain portion to the bottom of the mountain portion is 1:1 to 1:4, and the thickness (Ts) of the separator is At least one of the above problems is solved by setting the ratio (Ts:Ta) of the thickness (Ta) of the first active material layer or the second active material layer to 1:100 to 1:500. There is.

Furthermore, by making the first-pole current collector and the second-pole current collector be corrugated current collectors each having a plurality of peaks and having a corrugated cross section, the current collector, the first-pole active material layer, and Since the contact area with the second electrode active material layer is increased, the interface resistance between the current collector and the active material layer can be reduced, which can also contribute to improvement in battery performance.

In addition, a plurality of peaks respectively included in the first pole current collector and the second pole current collector are arranged at predetermined intervals along the first direction in parallel and alternately with the peaks facing each other through the separator. By doing so, the area of the interface between the first pole and the second pole can be increased as compared with the case of using the flat plate-like separator, so that the interface resistance becomes small and when the flat plate-like separator is used. Compared with this, the battery performance can be improved. The area of the interface between the first pole and the second pole can be increased by using a corrugated separator. However, when the current collector is flat, the separator and the current collector are separated from each other. Since the distance is not uniform and the electrochemical reaction in the active material layer is not uniform, the battery is likely to deteriorate. However, in the present invention, the first pole current collector and the second pole current collector are Since the distance to the separator is uniform, the electrochemical reaction in the active material layer is uniform and the durability of the battery is excellent.

Here, it is preferable that the upper portion of the mountain portion of each of the first-pole current collector and the second-pole current collector has a continuous curved surface from the first side surface to the apex to the second side surface.

According to the present invention, it is possible to provide a lithium ion battery that can be made large in size at low cost and that can secure an appropriate battery capacity.

It is a partially broken perspective view showing a lithium ion battery which is one embodiment of the present invention. FIG. 3 is a partially cutaway perspective view showing a part of a lithium ion battery according to one embodiment. FIG. 4 is a process chart showing a method for manufacturing a lithium-ion battery that is an embodiment of the present invention. It is sectional drawing which shows the electrical power collector used for the lithium ion battery of one Embodiment. It is a perspective view which shows the collector support body used for the lithium ion battery of one Embodiment.

(One embodiment)
With reference to FIG. 1 and FIG. 2, details of a lithium ion battery according to an embodiment of the present invention will be described. FIG. 1 is a partially cutaway perspective view showing a lithium ion battery according to an embodiment of the present invention, and FIG. 2 is a partially cutaway perspective view showing a part of a lithium ion battery according to one embodiment.

In these figures, a lithium ion battery L of the present embodiment includes a lithium secondary cell 1 having a substantially rectangular parallelepiped shape, and a housing 20 that is an exterior body that houses the lithium secondary cell 1. The lithium ion battery L of this embodiment has a length direction (X axis direction in FIG. 1) of about 10 m, a thickness direction (Y axis direction of FIG. 1) of about 10 cm, and a height direction (Z axis in FIG. 1). It is formed in a size of 1 to several meters in the axial direction).

Here, in the present invention, the lithium secondary battery 1 is a positive electrode in which a positive electrode composition layer containing a positive electrode active material and an electrolytic solution is formed on the surface of a positive electrode current collector, a negative electrode active material and an electrolytic solution. And a negative electrode having a negative electrode composition layer formed on the surface of a negative electrode current collector, having a structure in which a positive electrode composition and a negative electrode composition are laminated via a separator, a battery container, It is a battery that does not have terminal arrangements, electronic control devices, etc. (Reference: Japanese Industrial Standard JIS C8715-2 “Industrial lithium secondary battery cell and battery system”). The lithium secondary cell 1 may be abbreviated as a cell.

As shown in detail in FIG. 2, the unit cell 1 has a substantially flat plate-shaped positive electrode composition layer (containing a positive electrode active material and an electrolytic solution on the surface of a positive electrode current collector (first electrode current collector) 7 ( A substantially flat plate-shaped negative electrode composition containing a positive electrode 2 on which a first electrode composition 5 is formed, and a negative electrode current collector (second electrode current collector) 8 on the surface of which also includes a negative electrode active material and an electrolytic solution. The negative electrode 3 on which the material layer (second electrode composition) is formed is laminated via a separator 4.

The shapes of the positive electrode current collector 7 and the negative electrode current collector 8, which are features of this embodiment, will be described in more detail with reference to FIGS. 2 and 4A. FIG. 4A is a cross-sectional view showing the positive electrode current collector 7 and the negative electrode current collector 8 used in the lithium-ion battery L of this embodiment. In the lithium-ion battery L of the present embodiment, the positive electrode current collector 7 and the negative electrode current collector 8 have substantially the same cross-sectional shape. Therefore, when describing the shapes, the positive electrode current collector 7 will be described as a representative.

As shown in FIGS. 2 and 4A, the positive electrode current collector 7 is periodically formed at predetermined intervals along the X axis that is the first direction in FIGS. 2 and 4, and is different from the X axis. It is a corrugated current collector having a corrugated cross section, which has a plurality of peaks 7a protruding in the second direction, more specifically in the Y-axis direction orthogonal to the X-axis.

More specifically, as best shown in FIG. 4( a ), the positive electrode current collector 7 has a substantially flat plate-shaped base portion 7 b extending in the X-axis direction and a cycle at predetermined intervals along the X-axis. And a plurality of ridges 7a that are formed in one direction and project in the Y-axis direction orthogonal to the X-axis from one surface of the base 7b. As best shown in FIG. 2, the positive electrode current collector 7 of the present embodiment has a configuration shown in FIG. 4 along the Z axis which is the width direction of the positive electrode current collector 7 and is orthogonal to the X axis and the Y axis, respectively. It is formed so as to extend while maintaining the sectional shape shown in a).

Preferably, the upper portion 7c of the ridge portion 7a of the positive electrode current collector 7 extends from the first side surface which is the right side surface 7d in FIG. The second side surface, which is the surface 7f, is formed to have a continuous curved surface. The positive electrode current collector 7 of the present embodiment is further formed to have a continuous curved surface extending over the right side surface 7d and one surface of the base portion 7b and the left side surface 7f and one surface of the base portion 7b.

As shown in FIG. 4A, the positive electrode current collector 7 has the maximum distance (ΔL) between the side surfaces 7d and 7f of the mountain portion 7a and the side surfaces 7d and 7f of the mountain portion 7a adjacent thereto in the cross section. And the ratio (ΔL:Lh) of the shortest distance (Lh) from the apex 7e of the mountain portion 7a to the bottom of the mountain portion 7a, that is, one surface of the base portion 7b is 1:1 to 1:4. ing. If Lh is less than 1 with respect to ΔL, the distance between the positive electrode current collector 7 and the negative electrode current collector 8 becomes too small, so that the positive electrode composition layer 5 and the negative electrode composition layer 6 are sufficiently formed. It becomes difficult to form an active material layer having a uniform thickness, and it becomes difficult to maintain a required battery capacity. When Lh with respect to ΔL exceeds 4, it is necessary to increase the thickness of the side surfaces 7d and 7f of the mountain portion 7a to secure the strength of the positive electrode current collector 7 and the negative electrode current collector 8. It becomes difficult to similarly form an active material layer having a sufficient thickness that constitutes the layer 5 and the negative electrode composition layer 6, and it becomes difficult to maintain the required battery capacity. As an example, it is preferable that ΔL is about 2 to 3 cm and Lh is about 5 to 8 cm.

In the lithium-ion battery L of the present embodiment, as shown in FIG. 2, the plurality of ridges 7 a and 8 a included in the positive electrode current collector 7 and the negative electrode current collector 8 respectively face each other via the separator 4. They are arranged alternately and in parallel with the portions 7a and 8a at predetermined intervals along the X axis that is the first direction. The positive electrode composition layer 5, the separator 4, and the negative electrode composition layer 6 are sequentially laminated between the peak portions 7a and 8a of the positive electrode current collector 7 and the negative electrode current collector 8 which face each other.

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 unit cell 1. The positional relationship between the electric body 8 and the separator 4 is determined so that a required space can be obtained.

Particularly, in the lithium-ion battery L of the present embodiment, the ratio (Ts:Ta) of the thickness (Ts) of the separator 4 and the thickness (Ta) of the positive electrode composition layer 5 or the negative electrode composition layer 6 is 1: It is set to 100 to 1:500.

The positive electrode active material contains positive electrode active material particles, and as the positive electrode active material particles, a composite oxide of lithium and a transition metal (for example, LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , Li(Ni—Mn—Co)O is used. ₂ and LiMn ₂ O ₄ and some of these transition metals replaced by other elements), transition metal oxides (eg MnO ₂ and V ₂ O ₅ ), transition metal sulfides (eg MoS ₂ and TiS). ₂ ) and conductive polymers (for example, polyaniline, polypyrrole, polythiophene, polyacetylene, poly-p-phenylene, and polycarbazole). These may be used in combination of two or more. As the positive electrode active material particles, a lithium-transition metal composite oxide is preferably used from the viewpoint of capacity and output characteristics.

Further, the negative electrode active material contains negative electrode active material particles, and as the negative electrode active material particles, graphite, non-graphitizable carbon, amorphous carbon, polymer compound fired body (for example, phenol resin and furan resin, etc. are fired). Carbonized), cokes (eg pitch coke, needle coke and petroleum coke), carbon fibers, conductive polymers (eg polyacetylene and polyquinoline), tin, silicon, and metal alloys (eg lithium-tin alloy) , Lithium-silicon alloys, lithium-aluminum alloys and lithium-aluminum-manganese alloys), and complex oxides of lithium and transition metals (eg Li ₄ Ti ₅ O ₁₂ etc.). These negative electrode active materials may be used alone or in combination of two or more.

In the unit cell 1, the positive electrode active material particles and the negative electrode active material particles are coated active material particles in which at least a part of the surface is coated with a coating agent containing a coating resin and a conductive additive from the viewpoint of durability and the like. Is preferred. When the periphery of the active material particles is covered with a coating material, the volume change of the electrode can be alleviated, the expansion of the electrode can be suppressed, and further the deterioration due to vibration or the like generated when worn on the wrist can be suppressed. .. The state in which the coating material is attached to the surfaces of the positive electrode active material particles and the negative electrode active material particles can be confirmed by observing a magnified observation image of the coated active material particles obtained by using an SEM or the like. ..

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. Among these, vinyl resin, urethane resin, polyester resin or polyamide resin is preferable.

The conductive additive is selected from materials having conductivity.

Materials having conductivity include metals [aluminum, stainless steel (SUS), silver, gold, copper, titanium, etc.], conductive carbon [graphite, carbon black, acetylene black, Vulcan (registered trademark), Ketjen black (registered trademark) Trademark), Black Pearl (registered trademark), furnace black, channel black, thermal lamp black, carbon nanotubes (single-walled carbon nanotubes and multi-walled carbon nanotubes, etc.), carbon nanohorns, carbon nanoballoons, hard carbon and fullerenes, etc.], and these However, the mixture is not limited to these.

These conductive aids may be used alone or in combination of two or more. Moreover, these alloys or metal oxides may be used. From the viewpoint of electrical stability, it is preferably aluminum, stainless steel, carbon, silver, gold, copper, titanium and a mixture thereof, more preferably silver, gold, aluminum, stainless steel and carbon, further preferably carbon. is there. In addition, these conductive aids may be those obtained by coating a non-conductive material such as a particle-based ceramic material or a resin material with a conductive material (metal of the above-mentioned conductive aid materials) by plating or the like. Good.

The shape of the conductive additive is not particularly limited, and those having a shape such as a spherical shape, an irregular shape, a fibrous shape, a single particle shape, an aggregate, and a combination thereof can be used. Therefore, it is preferably an aggregate of fine particles having a primary particle diameter of 5 to 50 nm. The shape of the conduction aid can be obtained by observing a magnified observation image of the conduction aid obtained using SEM or the like and measuring particles in the visual field.

It is also possible to use conductive fibers as the conductive additive. Examples of the conductive fibers include carbon fibers such as PAN-based carbon fibers and pitch-based carbon fibers, conductive fibers obtained by uniformly dispersing metal having good conductivity and graphite in synthetic fibers, and metals such as stainless steel. Examples include fibrous metal fibers, conductive fibers obtained by coating the surface of organic fibers with a metal, and conductive fibers obtained by coating the surface of organic fibers with a resin containing a conductive substance. Among these conductive fibers, carbon fiber is preferable.

The coated active material particles are, for example, in a state where the active material particles are put in a universal mixer and stirred at 30 to 500 rpm, a resin solution containing a coating resin and a conductive additive used as necessary is dropped and mixed over 1 to 90 minutes. Then, a conductive auxiliary agent to be used is further mixed if necessary, the temperature is raised to 50 to 200° C. with stirring, the pressure is reduced to 0.007 to 0.04 MPa, and then the temperature is maintained for 10 to 150 minutes. The obtained coated active material particles can be confirmed by observing a magnified observation image of the coated active material particles obtained using a scanning electron microscope (also referred to as SEM).

As the electrolytic solution, it is possible to use an electrolytic solution containing an electrolyte and a non-aqueous solvent, which is used for manufacturing a lithium ion battery.

As the electrolyte, it is possible to use those which are used in a normal electrolytic solution, and 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 ) ₂ , lithium salts of organic acids such as LiN(C ₂ F ₅ SO ₂ ) ₂ and LiC(CF ₃ SO ₂ ) _{3 and the} like, and these electrolytes may be used alone or in combination. You may use together the above. Of these, LiPF ₆ is preferable from the viewpoint of battery output and charge/discharge cycle characteristics.

As the non-aqueous solvent, those which are used in ordinary electrolytic solutions can be used, and examples thereof include lactone compounds, cyclic or chain carbonic acid esters, chain carboxylic acid esters, cyclic or chain ethers, phosphoric acid esters, and nitriles. Compounds, amide compounds, sulfones, sulfolanes, etc. and mixtures thereof can be used.

As the electrolytic solution used for the lithium ion battery L of the present invention, a nonflammable ionic liquid can be preferably used from the viewpoint of safety. The ionic liquid is a salt composed of only cations and anions, and refers to a series of compounds that are liquid at room temperature. Examples of preferable ionic liquids include 1-methyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and N-methyl-N-propylpyrrolidium bis(trifluoromethanesulfonyl)imide.

The non-aqueous solvent may be used alone or in combination of two or more.

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

In the present invention, the positive electrode active material layer and the negative electrode active material layer preferably contain the above-mentioned coated active material particles and the fibrous conductive material, respectively, from the viewpoint of reducing ionic resistance and the like. As the fibrous conductive substance, the same one as the above-mentioned conductive fiber can be used, and among them, carbon fiber is preferable.

The thickness of the positive electrode composition layer 5 and the negative electrode composition layer 6 is preferably about 1 to 5 mm. With this thickness, the amount of active material per unit volume increases, and a battery having a large storage capacity can be obtained.

As the separator 4, a hydrocarbon-based resin such as polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP) and a porous film made of polyolefin (polyethylene, polypropylene, etc.), a multilayer film of a porous film (for example, PP/PE/ A microporous film made of a non-woven fabric composed of a PP three-layer structure), polyester fiber, aramid fiber, glass fiber, etc., and those having ceramic fine particles such as silica, alumina, titania, etc. attached to the surface thereof. The known lithium-ion battery separator or the like can be used.

The thickness of the separator 4 can be adjusted depending on the application of the lithium ion battery, but is preferably several tens of μm.

The pore size of the separator 4 made of the porous film or the multilayer film thereof is preferably 1 μm or less at the maximum (usually, it is about several tens nm).

As the positive electrode current collector 7 and the negative electrode current collector 8, known metal current collectors or resin current collectors can be used, and among them, resin current collectors are preferable. The positive electrode current collector 7 and the negative electrode current collector 8 that are resin current collectors are made of a non-conductive polymer material having conductivity even if the resin current collector is made of a conductive polymer material. It may be a resin current collector.

As the metal used for the metal current collector, the same metal as that used for the metal current collector generally used for lithium ion batteries can be used, and copper, aluminum, titanium, nickel, tantalum, niobium, hafnium, zirconium can be used. , Zinc, tungsten, bismuth, antimony, alloys containing one or more of these, and stainless steel alloys.

When the positive electrode current collector 7 and the negative electrode current collector 8 are resin current collectors, conductive polymer materials among the polymer materials forming the resin current collector include polyaniline, polypyrrole, polythiophene, polyacetylene, and polyacetylene. Paraphenylene, polyphenylene vinylene, polyacrylonitrile, polyoxadiazole, etc. are mentioned.

Examples of non-conductive polymer materials include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polycycloolefin (PCO), polyethylene terephthalate (PET), polyether nitrile (PEN), polytetrafluoroethylene. (PTFE), styrene butadiene rubber (SBR), polyacrylonitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVdF), epoxy resin, silicone resin, or a mixture thereof. To be

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, a conductive filler for the purpose of improving the conductivity of the resin current collector composed of a conductive polymer material, or for the purpose of imparting conductivity to the non-conductive polymer material. It is preferable to include it. The conductive filler is selected from fillers obtained from materials having conductivity. As the material having conductivity, it is preferable to use a material having no conductivity with respect to the ions used as the charge transfer medium, from the viewpoint of suppressing the permeation of ions in the current collector. 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 (SUS). However, the filler is not limited to these, and from the viewpoint of corrosion resistance, it is preferably a filler obtained from aluminum, stainless steel, a carbon material, nickel, and more preferably a carbon material. These conductive fillers may be used alone or in combination of two or more. Further, these conductive fillers may be obtained by coating the above-described metal with plating or the like around a particle-based ceramic material or a resin material.

The resin current collector can be obtained by a known method described in JP 2012-150905 A, International Publication No. WO 2015/005116 or the like, and specific examples thereof include polypropylene and acetylene black 5 as a conductive filler. After being dispersed in 20 parts, a product obtained by rolling with a hot press machine can be mentioned. Further, the thickness thereof is not particularly limited, and it can be applied in the same manner as a known one or by appropriately changing it.

The positive electrode current collector 7 and the negative electrode current collector 8 of the present embodiment may be formed of a substantially uniform material as a whole as shown in FIG. 4A, or as shown in FIG. 4B. , Electrical contact with the positive electrode composition layer 5 and the negative electrode composition layer 6 is enhanced on the surfaces of the positive electrode current collector 7 and the negative electrode current collector 8 (only the positive electrode current collector 7 is shown in the figure). The conductive layer 10 may be formed for the above reasons.

The positive electrode current collector 7 and the negative electrode current collector 8 which are wholly formed of a substantially uniform material have a predetermined shape made of the polymer material forming the metal or resin current collector forming the metal current collector. It can be obtained by a method of directly molding into a predetermined shape using a mold.

In addition, the positive electrode current collector 7 and the negative electrode current collector 8 can operate as the lithium ion battery L of the present embodiment if they have a predetermined thickness, for example, a thickness of several tens μm to several mm. Therefore, as shown in FIG. 4C, the insulating layer 12 is formed on the surface of the current collector support 11 having substantially the same cross-sectional shape as the positive electrode current collector 7 and the negative electrode current collector 8 shown in FIG. 4A. The positive electrode current collector 7 and the negative electrode current collector 8 (only the positive electrode current collector 7 is shown in the figure) having the above-described thickness may be formed on the surface of the insulating layer 12.

An example of the current collector support 11 shown in FIG. 4C is shown in FIGS. 5A and 5B. The current collector support 11 shown in FIG. 5A has a current collector support 11 formed by bending a thin plate such as a metal plate into a predetermined shape. On the other hand, in the current collector support 11 shown in FIG. 5B, a mountain-shaped member 11b having substantially the same shape as the mountain portion 7a of the positive electrode current collector 7 is arranged in parallel on the upper surface of the plate-shaped support plate 11a in the figure. Further, the chevron-shaped member 11b is fixed to the support plate 11a with a bolt 11c or the like.

The insulating layer 12 is provided on the current collector support 11 formed by the above method. The insulating layer 12 can use the coating film made of the above-mentioned non-conductive polymer material, and a method of applying a heat-melted non-conductive polymer material and a film-like substrate made of the non-conductive polymer material are laminated. It can be provided by a method or the like.

The positive electrode current collector 7 and the negative electrode current collector 8 described above are formed on the surface of the insulating layer 12. As a method of forming the positive electrode current collector 7 and the negative electrode current collector 8 on the surface of the insulating layer 12, the polymer material forming the metal or resin current collector forming the metal current collector is formed into a film shape. Examples of the method include arranging the film-shaped current collector described above on the surface of the insulating layer 12. The positive electrode current collector 7 and the negative electrode current collector 8 arranged on the surface of the insulating layer 12 may be fixed to the insulating layer 12 using a known adhesive or adhesive.

When the positive electrode current collector 7 and the negative electrode current collector 8 are metal current collectors, the film-shaped current collector arranged on the surface of the insulating layer 12 can be obtained by rolling the above-mentioned metal by a known method. You can When the positive electrode current collector 7 and the negative electrode current collector 8 are resin current collectors, the conductive polymer material or the non-conductive polymer material having conductivity is injection-molded and compressed. It can be obtained by molding into a film by a known method such as molding, calendar molding, slush molding, rotational molding, extrusion molding, blow molding, film molding (casting method, tenter method, inflation method, etc.).

The casing 20 that constitutes the lithium-ion battery L of the present embodiment is formed in a hollow external shape of a substantially rectangular parallelepiped, and the unit cell 1 is stored in the hollow portion of the casing 20. The housing 20 is divided into a first housing 21 and a second housing 22, as shown in detail in FIG. Protrusions 21a and 22a are formed at both ends (the front left end and the rear right end in FIG. 1) of the first casing 21 and the second casing 22, respectively, and the protrusions 21a and 22a are not shown. The first housing 21 and the second housing 22 are fixed to each other by being fixed to each other with the bolts or the like.

As the material of the exterior material forming the housing 20 including the first housing 21 and the second housing 22, any material is preferable as long as the material can store the unit cell 1 in the housing 20. Applicable. However, considering that there is a possibility that the unit cell 1 and the case 20 may come into contact with each other, the material forming the case 20 is preferably a material having an insulating property. In addition, the lithium-ion battery L of the present embodiment may be installed in the vicinity of a power plant for a long period of time, and thus is preferably made of a weather resistant material.

Next, a method for manufacturing the lithium-ion battery of this embodiment will be described with reference to FIG.

First, as shown in FIG. 3A, the positive electrode current collector 7 having a predetermined shape is housed in the first casing 21, and then the positive electrode composition layer 5 is contained in the first casing 21. To fill. There is no limitation on the method of filling the positive electrode composition layer 5 in the first housing 21, and as an example, as shown in FIG. 3A, the nozzle 30 is stored in the tank in which the positive electrode composition layer 5 is stored. A method of filling the positive electrode composition layer 5 in the first casing 21 via a via, a method of filling the positive electrode composition layer 5 in the first casing 21 with an inkjet device, and a known method are preferable. Applied to.

Next, as shown in FIG. 3B, a mold 31 having a surface similar to the surface shape of the positive electrode current collector 7, more specifically, a surface at a constant distance from the surface of the positive electrode current collector 7, is formed into a first mold. By inserting into the case 21, the positive electrode composition layer 5 having a constant thickness is formed on the surface of the positive electrode current collector 7.

Furthermore, by disposing the flat plate-shaped separator 4 on the upper surface of the positive electrode composition layer 5, the opening 21c is covered with the separator 4 as shown in FIG. The method of arranging the separator 4 is arbitrary, and as an example, as shown in FIG. 3C, the separator 4 processed (including cutting) to a predetermined size is held by a vacuum chuck 32 or the like and the positive electrode is held. A method of disposing the separator 4 above the composition layer 5 and lowering the vacuum chuck 32 to dispose (place) the separator 4 on the upper surface of the positive electrode composition layer 5 can be mentioned.

Next, as shown in FIG. 3E, the negative electrode current collector 8 having a predetermined shape is housed in the second casing 22, and then the negative electrode composition layer 6 is contained in the second casing 22. To fill. The method of filling the negative electrode composition layer 6 in the second housing 22 is not limited, and various methods can be adopted as in the method of housing the positive electrode composition layer 5.

Next, as shown in FIG. 3( f ), a mold 33 having a surface at a constant distance from the surface of the negative electrode current collector 8 is inserted into the second housing 22 to remove the negative electrode current collector 8 from the negative electrode current collector 8. A negative electrode composition layer 6 having a constant thickness is formed on the surface.

Next, as shown in FIG. 3(g), the positive electrode composition layer 5 and the positive electrode current collector 7 are accommodated so that the separator 4 is located below, that is, turned over from the state shown in FIG. 3(d). The second case in which the negative electrode composition layer 6 and the negative electrode current collector 8 are housed so that the separator 4 and the negative electrode composition layer 6 are in contact with each other in this state. The first casing 21 is housed in the casing 22. Thereby, the positive electrode composition layer 5 and the negative electrode composition layer 6 face each other via the separator 4.

Then, as shown in FIG. 3(h), by fixing the projecting portion 21a of the first housing 21 and the projecting portion 22a of the second housing 22 with the bolts 34 or the like, the unit cell 1 is internally provided. The stored lithium ion battery L of this embodiment can be manufactured.

Therefore, in the lithium-ion battery L of the present embodiment, the film thickness of the positive electrode composition layer 5 and the negative electrode composition layer 6 can be made sufficiently thick, so that the battery capacity per unit volume can be increased and Since it is not necessary to form a large number of electrode composition layers, the cost can be increased and the size can be increased. As described above, according to the present embodiment, it is possible to provide a lithium-ion battery that can be made large in size at low cost and can secure an appropriate battery capacity, and a method for manufacturing the same.

L Lithium ion battery 1 Single cell 2 Positive electrode 3 Negative electrode 4 Separator 5 Positive electrode composition layer 6 Negative electrode composition layer 7 Positive electrode collector 7a, 8a Mountain part 7b Base part 7c Upper part 7d Right side face 7e Vertex 7f Left side face 8 Negative electrode collection Electric body 20 Housing 21 First housing 22 Second housing 21a, 22a Projection part

Claims (2)

A lithium ion battery in which a first electrode current collector, a first electrode active material layer, a separator, a second electrode active material layer, and a second electrode current collector are sequentially laminated,
Each of the first pole current collector and the second pole current collector is periodically formed along the first direction at a predetermined interval and protrudes in a second direction different from the first direction. Is a corrugated current collector having a wave-shaped cross section,
The plurality of ridges that the first pole current collector and the second pole current collector have, respectively, are arranged in parallel with the ridge portions that face each other in an alternating manner in parallel with the first direction via the separator. It is arranged at a predetermined interval,
In each of the cross sections of the first pole current collector and the second pole current collector, the maximum distance (ΔL) between the side surface of the mountain portion and the side surface of the mountain portion adjacent thereto and the apex of the mountain portion. To the bottom of the mountain portion (Lh), the ratio (ΔL:Lh) is 1:1 to 1:4,
The ratio (Ts:Ta) of the thickness (Ts) of the separator and the thickness (Ta) of the first electrode active material layer or the second electrode active material layer is 1:100 to 1:500. And a lithium-ion battery. The upper portion of the mountain portion included in each of the first pole current collector and the second pole current collector has a curved surface that is continuous from the first side surface to the apex of the second side surface. The lithium-ion battery described in.

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