JP2019133779A - Laminated battery - Google Patents

Abstract

To improve volume energy density of a laminated battery.SOLUTION: A laminated battery comprises: an electrode body having a positive electrode and a negative electrode; an electrode tab led out from the electrode body; an electrode terminal electrically connected to the electrode tab; and an outer package for housing the electrode body and the electrode terminal. The laminated battery further comprises: an electrode terminal joint part at which the electrode tab is welded to the electrode terminal; and a seal part for sealing the electrode tab, the electrode terminal, and the outer package. When viewing the laminated battery from the in-plane direction, the electrode tab, the electrode terminal, the outer package, and the seal part are aligned on one cross section.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a stacked battery.

  Patent Document 1 discloses the following contents as a technology related to the stacked battery. Inside the laminate film 2, the edge 12 of the positive electrode current collector 4, the burr 11 of the ultrasonic weld 9 in which the positive electrode current collector 4 and the positive electrode tab 6 are welded by ultrasonic welding, and the positive electrode current collector A protective sheet 8 is attached to a region covering the edge 10 of the positive electrode tab 6 on the side connected to the electric part 4.

JP 2012-33449 A

  In Patent Document 1, since the positive electrode current collector 4 and the positive electrode tab 6 are connected by ultrasonic welding and sealed by the laminate film 2 outside the welded portion, the seal portion becomes a dead space, and the laminated battery There is a possibility that the volumetric energy density of the material will decrease.

  An object of this invention is to improve the volume energy density of a laminated battery.

  The features of the present invention for solving the above problems are as follows, for example.

  A stacked battery comprising: an electrode body having a positive electrode and a negative electrode; an electrode tab derived from the electrode body; an electrode terminal electrically connected to the electrode tab; and an exterior body that houses the electrode body and the electrode terminal. The electrode tab and the electrode terminal are welded to the electrode terminal joint, and the electrode tab, the electrode terminal, and a seal portion for sealing the exterior body, and when viewing the stacked battery from the in-plane direction, A stacked battery in which an electrode tab, an electrode terminal, an exterior body, and a seal portion are arranged in one section.

  According to the present invention, it is possible to improve the volume energy density of the stacked battery. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

FIG. FIG. FIG. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description shows specific examples of the contents of the present invention, and the present invention is not limited to these descriptions. Various modifications by those skilled in the art are within the scope of the technical idea disclosed in this specification. Changes and modifications are possible. In all the drawings for explaining the present invention, components having the same function are denoted by the same reference numerals, and repeated description thereof may be omitted.

  “˜” described in the present specification is used in the sense of including the numerical values described before and after it as lower and upper limits. In the numerical ranges described stepwise in this specification, the upper limit value or lower limit value described in one numerical range may be replaced with the upper limit value or lower limit value described in another stepwise manner. The upper limit value or lower limit value of the numerical ranges described in the present specification may be replaced with the values shown in the examples.

  In this specification, a lithium ion secondary battery will be described as an example of a stacked battery. A lithium ion secondary battery is an electrochemical device that can store or use electrical energy by occluding / releasing lithium ions to and from an electrode in an electrolyte. This is called by another name of a lithium ion battery, a non-aqueous electrolyte secondary battery, and a non-aqueous electrolyte secondary battery, and any battery is a subject of the present invention. The technical idea of the present invention can also be applied to sodium ion secondary batteries, magnesium ion secondary batteries, calcium ion secondary batteries, zinc secondary batteries, aluminum ion secondary batteries, and the like.

  FIG. 1 is an external view of a stacked battery. The stacked battery 1000 includes a positive electrode 100 (electrode), a negative electrode 200 (electrode), a positive electrode terminal 150 (electrode terminal), a negative electrode terminal 250 (electrode terminal), a separator 300, an outer package 500, an electrode terminal joint portion 600, and a seal portion 700. Have

  The positive electrode 100 includes a positive electrode mixture layer 110 (electrode mixture layer), a positive electrode current collector 120, and a positive electrode tab 130 (electrode tab). A positive electrode mixture layer 110 is formed on both surfaces of the positive electrode current collector 120 (electrode current collector). It has a negative electrode 200, a negative electrode mixture layer 210 (electrode mixture layer), a negative electrode current collector 220 (electrode current collector), and a negative electrode tab 230 (electrode tab). Negative electrode mixture layers 210 are formed on both surfaces of the negative electrode current collector 220.

  The positive electrode 100, the separator 300, and the negative electrode 200 are laminated to form an electrode body 400. The stacked battery 1000 is configured by stacking a plurality of electrode bodies 400. By connecting the positive electrode tabs 130 to each other and the negative electrode tab 230, an electrical parallel connection is configured in the stacked battery 1000. A stacked battery 1000 in FIG. 1 is a stacked secondary battery.

<Electrode mixture layer>
The positive electrode mixture layer 110 has a positive electrode active material capable of inserting and extracting Li. Examples of the positive electrode active material include LiCo-based oxides, LiNi-based composite oxides, LiMn-based composite oxides, Li-Co-Ni-Mn composite oxides, LiFeP-based oxides, and the like. The negative electrode mixture layer 210 has a negative electrode active material capable of inserting and extracting Li. Examples of the negative electrode active material include carbon-based materials such as natural graphite, soft carbon, and amorphous carbon, Si metal, Si alloy, lithium titanate, and lithium metal.

  In the electrode mixture layer, a positive electrode conductive agent responsible for electron conductivity in the electrode mixture layer, a binder that ensures adhesion between materials in the electrode mixture layer, and ion conductivity in the electrode mixture layer A solid electrolyte may be included to ensure

  A method for producing the electrode mixture layer is, for example, as follows. First, the material contained in the electrode mixture layer is dissolved in a solvent to form a slurry, which is applied onto the electrode current collector. Examples of the coating method include a doctor blade method, a dipping method, and a spray method. Next, in order to remove the solvent, the electrode mixture layer coated on the electrode current collector is dried. Next, the electrode mixture layer is pressed to ensure electron conductivity and ion conductivity in the electrode mixture layer.

<Electrode current collector, electrode tab>
The electrode current collector is electrically connected to the electrode tab. The electrode tab is led out to the side surface of the electrode current collector. In FIG. 1, the electrode mixture layer is not formed on the electrode tab. However, the electrode mixture layer may be formed on the electrode tab as long as the battery performance is not adversely affected.

  For the positive electrode current collector 120 and the positive electrode tab 130, an aluminum foil, a perforated foil made of aluminum having a hole diameter of 0.1 mm to 10 mm, an expanded metal, an aluminum foam plate, or the like can be applied. As the material, stainless steel, titanium, etc. can be applied in addition to aluminum.

  For the negative electrode current collector 220 and the negative electrode tab 230, a copper foil, a copper perforated foil having a hole diameter of 0.1 mm to 10 mm, an expanded metal, a foamed copper plate, or the like is used. In addition to copper, stainless steel, titanium, nickel, etc. can be applied as the material.

  The thickness of the electrode current collector and the electrode tab is preferably 10 nm to 1 mm. From the viewpoint of achieving both the energy density of the laminated battery 1000 and the mechanical strength of the electrode, about 1 μm to 100 μm is desirable.

<Separator 300>
The separator 300 is formed between the positive electrode 100 and the negative electrode 200. When the stacked battery 1000 is a lithium ion stacked battery, the separator 300 transmits lithium ions and prevents a short circuit between the positive electrode 100 and the negative electrode 200. As a material constituting the separator 300, a microporous film, a solid electrolyte, or the like can be used.

  As the microporous film, polyolefin such as polyethylene or polypropylene, glass fiber, or the like can be used. When a microporous membrane is used for the separator 300, the electrolyte solution is injected into the laminated battery 1000 from the vacant side or the injection hole of the exterior body that houses the plurality of electrode bodies 400. Is filled with an electrolyte solution.

The electrolytic solution includes, for example, a solvent and a lithium salt, and serves as a medium for transmitting lithium ions between the positive electrode 100 and the negative electrode 200. Use ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), propylene carbonate, butylene carbonate, γ-butyrolactone, phosphate triester, trimethoxymethane, dioxolane, diethyl ether, sulfolane, etc. as solvents. Can do. These materials may be used alone or in combination. Examples of the lithium _{salt, LiPF 6, LiBF 4, LiClO} 4, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, lithium bis oxalate borate (LiBOB), lithium imide salt (e.g., lithium bis (Fluorosulfonyl) imide, LiFSI) and the like can be preferably used. These lithium salts may be used alone or in combination.

As solid electrolytes, organic polymers and inorganic particles such as sulfides such as Li ₁₀ Ge ₂ PS ₁₂ and Li ₂ SP ₂ S ₅ , oxides such as Li-La-Zr-O, ionic liquids and room temperature molten salts, etc. A semi-solid electrolyte supported on the gel, a gel electrolyte using a polymer gel as an electrolyte, or the like can be used. When a solid electrolyte is used as the separator 300, the solid electrolyte serves as a medium for transmitting lithium ions between the positive electrode 100 and the negative electrode 200, and the above-described electrolyte is basically unnecessary. You can configure the connection. However, an electrolytic solution may be added to the multilayer battery 1000 even when a solid electrolyte is used as the separator 300 as long as an electrical short circuit in the multilayer battery 1000 can be prevented.

  The separator 300 may be formed between the positive electrode 100 and the negative electrode 200 as a sheet, or may be formed by coating on the electrode mixture layer. The separator 300 may be formed on both surfaces of the electrode mixture layer, and if the separator 300 is formed between the positive electrode 100 and the negative electrode 200, the separator 300 may be formed on one surface of the electrode mixture layer. The thickness of the separator 300 is several nanometers to several millimeters from the viewpoint of ensuring the energy density of the multilayer battery 1000, ensuring electronic insulation, and the like.

<Electrode terminal>
The electrode terminal is electrically connected to the electrode tab. As materials for the positive electrode terminal 150 and the negative electrode terminal 250, metals such as aluminum, copper, nickel, and stainless steel can be used.

<Exterior body 500>
The exterior body 500 houses the electrode body 400 and electrode terminals. In order to electrically connect the electrode terminal to the bus bar, an opening is formed in the exterior body 500 so that the electrode terminal is exposed on the surface of the exterior body 500 where the electrode terminal is formed. The material of the outer package 500 is selected from materials that are corrosion resistant to the electrolyte, such as aluminum, stainless steel, and nickel-plated steel.

<Electrode terminal joint 600>
By welding the electrode tab and the electrode terminal by, for example, ultrasonic welding, an electrode terminal joint portion 600 in which the electrode tab and the electrode terminal are joined is formed.

<Seal part 700>
By thermally fusing the electrode terminal joint portion 600 with a sealant, a seal portion 700 that seals the stacked battery 1000 (electrode tab, electrode terminal, exterior body 500) is formed. At this time, when the multilayer battery 1000 is viewed from the in-plane direction, the electrode tab, the electrode terminal, the exterior body 500, and the seal portion 700 are arranged in one section. Thus, conventionally, when the laminated battery 1000 is sealed, the electrode terminal joint portion 600 and the seal portion 700 that are arranged in the in-plane direction of the laminated battery 1000 can be integrated into one cross section. Dead space can be reduced and the volume energy density of the stacked battery 1000 can be improved.

  Examples of the sealant material include polypropylene, polyethylene, polyolefin resin, and the like, which have a function of being deformed by heat and closely contacting the constituent members of the laminated battery 1000.

  In FIG. 1, the electrode tab is formed inside the seal portion 700 in the in-plane direction of the stacked battery 1000. This prevents contact between the electrode tab and outside air, and prevents corrosion of the electrode tab.

  FIG. 2 is an external view of a stacked battery. In FIG. 2, one cross section constituted by the electrode tab, the electrode terminal, the outer package 500, and the seal portion 700 is inclined with respect to the stacking direction of the stacked battery 1000. Specifically, in the in-plane direction of the multilayer battery 1000, the electrode tab led out of the area of the exterior body 500 that houses the electrode body 400 is bent, and the electrode terminal joint portion 600 and the seal portion 700 are laminated. The battery 1000 is oriented in the stacking direction. Thereby, the dead space of the laminated battery 1000 generated by the electrode terminals can be reduced, and the volume energy density of the laminated battery 1000 can be improved.

  The extending direction of the electrode tab is substantially perpendicular to the in-plane direction of the stacked battery 1000, but it may be inclined even if it is not perpendicular. In that case, the position of the tip of the tilted electrode tab projected in the thickness direction of the electrode body 400 is within the width in the stacking direction of the electrode body 400, thereby improving the volume energy density. Can do.

  The exterior body 500 is also bonded to three sides of the side surface of the electrode body 400 except the side where the electrode tab is disposed. At this time, it is desirable that the width of the joint portion of the outer package 500 on the three sides is inclined with respect to the stacking direction of the stacked battery 1000. In other words, the position of the point projected in the thickness direction of the electrode body 400 at the tip of the joint portion of the inclined exterior body 500 is within the width in the stacking direction of the electrode body 400. desirable. Thereby, the dead space of the laminated battery 1000 generated by the outer package 500 can be reduced, and the volume energy density of the laminated battery 1000 can be improved.

  In the in-plane direction of the laminated battery 1000, it is desirable that one cross section constituted by the inclined outer casing 500 and the seal portion 700 is formed on the outer peripheral side from the joint portion of the inclined outer casing 500. Thereby, the productivity of the stacked battery 1000 can be improved.

  FIG. 3 is an external view of a stacked battery. In FIG. 3, the electrode terminal joint portion 600 and the seal portion 700 are formed in the lower portion in the stacking direction of the stacked battery 1000. Specifically, a plurality of electrode tabs are bundled at the position where the electrode tabs at the bottom of the electrode body 400 are formed, and the electrode tabs are bundled from the position at which the electrode tabs at the bottom of the electrode body 400 are formed. Is bent. Further, the outer package 500 arranged at the lower part of the stacked battery 1000 in the stacking direction is not bent in the stacking direction of the stacked battery 1000 as shown in FIG. 2, and extends in the in-plane direction of the stacked battery 1000. doing. Thereby, the length of an electrode terminal can be enlarged.

  It is not necessary to bundle a plurality of electrode tabs at the position where the electrode tab at the bottom of the electrode body 400 is formed, and is approximately lower than 1/2 of the film thickness in the stacking direction of the stacked battery 1000, preferably 1/3 It is desirable that a plurality of electrode tabs are bundled at the lower part.

  FIG. 4 is an external view of a stacked battery. In FIG. 4, when viewed from the stacking direction of the stacked battery 1000, the separator 300 is formed larger than the electrodes. Specifically, the separator 300 is formed so as to cover part or all of the electrode end portions. Thereby, when the electrode tab is bent, a short circuit between an electrode different from the electrode corresponding to the bent electrode tab and the bent electrode tab can be prevented.

100 positive electrode, 110 positive electrode mixture layer, 120 positive electrode current collector, 130 positive electrode tab, 150 positive electrode terminal
200 negative electrode, 210 negative electrode mixture layer, 220 negative electrode current collector, 230 negative electrode tab, 250 negative electrode terminal
300 separator
400 electrode body
500 exterior body
600 Electrode terminal joint
700 Sealing part
1000 Stacked battery

Claims (6)

An electrode body having a positive electrode and a negative electrode; an electrode tab derived from the electrode body; and an electrode terminal electrically connected to the electrode tab;
A laminated battery having the electrode body and an exterior body for housing the electrode terminal,
An electrode terminal joint where the electrode tab and the electrode terminal are welded;
A seal portion for sealing the electrode tab, the electrode terminal, and the exterior body;
When the laminated battery is viewed from the in-plane direction, the laminated battery in which the electrode tab, the electrode terminal, the exterior body, and the seal portion are arranged in one section. In the stacked battery of claim 1,
In the in-plane direction of the stacked battery, the electrode tab is formed inside the seal portion. In the stacked battery of claim 1,
The laminated battery in which the one cross section is inclined with respect to the lamination direction of the laminated battery. In the stacked battery according to claim 3,
The stacked battery in which the position of the tip of the electrode tab projected in the thickness direction of the electrode body is contained within the width of the electrode body in the stacking direction. In the stacked battery of claim 1,
A stacked battery in which the electrode terminal joint and the seal portion are formed in a lower part in the stacking direction of the stacked battery. In the stacked battery of claim 1,
The electrode body has a separator for separating the positive electrode and the negative electrode,
When viewed from the stacking direction of the stacked battery, the separator is a stacked battery larger than the positive electrode or the negative electrode.

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