JP2018113190A - Manufacturing method of multilayer secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve productivity of a laminated secondary battery. SOLUTION: A step of applying a positive electrode mixture layer to a positive electrode current collector to produce a positive electrode so that a positive electrode coated portion and a positive electrode uncoated portion are formed, and a step of forming a separator on the positive electrode. A step of applying a negative electrode mixture layer to the negative electrode current collector, producing a negative electrode so that a negative electrode coated portion and a negative electrode uncoated portion are formed, and a step of forming a separator on the negative electrode, Laminate the positive electrode and negative electrode so that one electrode-coated part and the other electrode-coated part overlap and one electrode-uncoated part does not overlap the other electrode-coated part and electrode-uncoated part. And a step of punching the positive electrode and the negative electrode at one time to form a positive electrode tab and a negative electrode tab in the uncoated portion of the positive electrode and the uncoated portion of the negative electrode. [Selection diagram] Figure 1

Description

  The present invention relates to a method for manufacturing a stacked secondary battery.

  In a stacked secondary battery such as a lithium ion secondary battery, a positive electrode, a negative electrode, and a separator are stacked. As a technique related to a stacked secondary battery, Patent Document 1 discloses an electrode sheet including an active material coated part in which an active material is applied to a metal foil for electrodes and an active material non-coated part in which no active material is applied. In the manufacturing method of the electrode that cuts 60, by setting the non-coated portion cutting scheduled portions 75 to 78 scheduled to be cut in the active material non-coated portion and stacking the plurality of electrode sheets 60, Non-coated portion of the electrode sheet 60 on which the non-coated portion cutting scheduled portions 75 to 78 are superposed, and the electrode sheet 60 having higher hardness than the electrode metal foil and positioned on the outermost side in the electrode sheet group 83 It is disclosed that a high-hardness covering body that covers the planned cutting portion is formed and the non-coating portion cutting planned portions 75 to 78 that are covered with the high-hardness covering body are cut.

Japanese Unexamined Patent Publication No. 2016-1000028

  In Patent Document 1, for electrical insulation between a positive electrode and a negative electrode, resin separators are sandwiched between them. Since the separator made of resin is weaker in mechanical strength than the metal foil which is the base material of the positive electrode and the negative electrode, it cannot be punched at the same time as the positive electrode and the negative electrode, and is separately punched and laminated. After stacking and punching the positive electrode and the negative electrode separately, and stacking the positive electrode and the negative electrode with a separator in between, it is necessary to align the electrodes. Productivity decreases. An object of the present invention is to improve the productivity of a stacked secondary battery.

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

  Applying a positive electrode mixture layer to the positive electrode current collector to form a positive electrode so that a positive electrode coated portion and a positive electrode uncoated portion are formed; forming a separator on the positive electrode; A step of applying a negative electrode mixture layer to an electric body to form a negative electrode so that a negative electrode coated portion and a negative electrode uncoated portion are formed; a step of forming a separator on the negative electrode; Laminating the positive electrode and the negative electrode so that one electrode uncoated portion does not overlap the other electrode coated portion and the electrode uncoated portion so that the working portion and the other electrode coated portion overlap, And a step of punching out the positive electrode and the negative electrode at a time to produce a positive electrode tab and a negative electrode tab in the uncoated part of the positive electrode and the uncoated part of the negative electrode.

  According to the present invention, the productivity of the stacked secondary battery can be improved. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

The perspective view of a laminated type secondary battery. The perspective view of a laminated type secondary battery. The perspective view of a laminated type secondary battery.

  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.

  In this embodiment, the positive electrode mixture layer 251 is applied to the positive electrode current collector 252 to produce the positive electrode 250 so that the positive electrode coated portion 253 and the positive electrode uncoated portion (positive electrode tab 254) are formed. The step of forming a separator (electrolyte layer 300) on the positive electrode 250, the negative electrode mixture layer 151 is applied to the negative electrode current collector 152, and the negative electrode coated portion 153 and the negative electrode uncoated portion (negative electrode tab 154) The process of forming the negative electrode 150 so as to form the electrode, the process of forming the separator on the negative electrode, and the application part of one electrode and the application part of the other electrode overlap each other. The step of laminating the positive electrode 250 and the negative electrode 150 so that the uncoated portion does not overlap with the coated portion and the uncoated portion of the other electrode, and the coated portion and the uncoated portion of the positive electrode 250 and the negative electrode 150 are once To the positive electrode coated part and negative electrode uncoated part. It adopts poles and process for manufacturing the tab 254 and the negative electrode tab 154, a manufacturing method of a stacked secondary battery comprising, a.

  FIG. 1 is a perspective view of a stacked secondary battery. The stacked secondary battery 1000 includes a positive electrode 250, an electrolyte layer 300, and a negative electrode 150. Hereinafter, the positive electrode 250 or the negative electrode 150 may be referred to as an electrode.

  The positive electrode 250 includes two positive electrode mixture layers 251 and a positive electrode current collector 252. In the positive electrode 250, positive electrode mixture layers 251 are formed on both surfaces of the positive electrode current collector 252. The negative electrode 150 includes a negative electrode mixture layer 151 and a negative electrode current collector 152. In the negative electrode 150, the negative electrode mixture layer 151 is formed on both surfaces of the negative electrode current collector 152.

  The positive electrode 250, the electrolyte layer 300, and the negative electrode 150 are laminated to form an electrode body. A plurality of electrode bodies are stacked, and the positive electrode current collectors 252 and the negative electrode current collector 152 in the electrode bodies are connected to each other, so that the stacked secondary battery 1000 is electrically connected in parallel. A plurality of electrode bodies are stacked to form a stacked secondary battery 1000.

<Positive electrode mixture layer 251>
The positive electrode mixture layer 251 contains at least a positive electrode active material capable of inserting and extracting Li. Examples of the positive electrode active material include LiCo composite oxide, LiNi composite oxide, LiMn composite oxide, Li—Co—Ni—Mn composite oxide, LiFeP composite oxide, and the like. In the positive electrode mixture layer 251, a conductive material responsible for electronic conductivity in the positive electrode mixture layer 251, a binder that ensures adhesion between the materials in the positive electrode mixture layer 251, and further in the positive electrode mixture layer 251 A solid electrolyte for ensuring ionic conductivity may be included.

  As a method for producing the positive electrode mixture layer 251, a material contained in the positive electrode mixture layer 251 is dissolved in a solvent to form a slurry, which is applied onto the positive electrode current collector 252. The coating method is not particularly limited, and for example, a conventional method such as a doctor blade method, a dipping method, or a spray method can be used. Then, the positive electrode mixture layer 251 is formed through a drying process for removing the solvent and a pressing process for ensuring the electron conductivity and ion conductivity in the positive electrode mixture layer 251.

<Positive electrode current collector 252>
The positive electrode current collector 252 has a positive electrode coating part 253 and a positive electrode tab 254. A positive electrode mixture layer 251 is formed on the positive electrode coating portion 253. The positive electrode mixture layer 251 is not formed on the positive electrode tab 254 and is a positive electrode uncoated portion. The positive electrode tab 254 is arranged to take out the generated electricity to the outside, and protrudes from one side of the positive electrode 250.

  The respective positive electrode tabs 254 in the stacked secondary battery 1000 are overlapped when the stacked secondary battery 1000 is viewed from the stacking direction. The plurality of positive electrode tabs 254 in the stacked secondary battery 1000 are bonded by, for example, ultrasonic bonding.

  For the positive electrode current collector 252, an aluminum foil, an aluminum perforated foil having a hole diameter of 0.1 to 10 mm, an expanded metal, a foamed aluminum plate, or the like is used. As the material, stainless steel, titanium, or the like can be applied in addition to aluminum. The thickness of the positive electrode current collector 252 is preferably 10 nm to 1 mm. About 1-100 micrometers is desirable from a viewpoint of the energy density of an all-solid-state battery and the mechanical strength of an electrode.

<Negative electrode mixture layer 151>
The negative electrode mixture layer 151 contains at least 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 negative electrode mixture layer 151, a conductive material responsible for electronic conductivity in the negative electrode mixture layer 151, a binder that ensures adhesion between the materials in the negative electrode mixture layer 151, and further in the negative electrode mixture layer 151 A solid electrolyte for ensuring ionic conductivity may be included.

  As a method for producing the negative electrode mixture layer 151, a material contained in the negative electrode mixture layer 151 is dissolved in a solvent to form a slurry, which is applied onto the negative electrode current collector 152. The coating method is not particularly limited, and for example, a conventional method such as a doctor blade method, a dipping method, or a spray method can be used. Thereafter, the negative electrode mixture layer 151 is formed through a drying process for removing the solvent and a pressing step for ensuring the electron conductivity and ion conductivity in the negative electrode mixture layer 151.

<Negative electrode current collector 152>
The negative electrode current collector 152 has a negative electrode coating part 153 and a negative electrode tab 154. The configurations of the negative electrode coating portion 153 and the negative electrode tab 154 are substantially the same as the configurations of the positive electrode coating portion 253 and the positive electrode tab 254. A negative electrode mixture layer 151 is formed on the negative electrode coating portion 153. The negative electrode mixture layer 151 is not formed on the negative electrode tab 154, and is a negative electrode uncoated portion.

  For the negative electrode current collector 152, a copper foil, a copper perforated foil having a hole diameter of 0.1 to 10 mm, an expanded metal, a foamed copper plate, or the like is used. In addition to copper, stainless steel, titanium, nickel, or the like can be applied. The thickness of the negative electrode current collector 152 is preferably 10 nm to 1 mm. About 1-100 micrometers is desirable from a viewpoint of the energy density of an all-solid-state battery and the mechanical strength of an electrode.

<Electrolyte layer 300>
Electrolyte layer 300 is formed on the surfaces of positive electrode mixture layer 251 and negative electrode mixture layer 151. Since the electrolyte layer 300 is formed on the surfaces of the positive electrode mixture layer 251 and the negative electrode mixture layer 151, the same shape can be punched at a time in a state where the positive electrode 250, the electrolyte layer 300, and the negative electrode 150 are stacked in this order.

  The electrolyte layer 300 includes a solid electrolyte. As solid electrolytes, semi-solid electrolytes that carry sulfides such as Li10Ge2PS12 and Li2S-P2S5, oxides such as Li-La-Zr-O, ionic liquids and room temperature molten salts on organic polymers and inorganic particles, etc. For example, a material that does not exhibit fluidity within the operating temperature range of an all-solid-state battery can be used. The electrolyte layer 300 is formed by compressing powder, mixing with a binder, applying a slurryed solid electrolyte layer to a release material, or impregnating a carrier. The thickness of the electrolyte layer 300 is several nanometers to several millimeters from the viewpoint of ensuring the energy density of the all solid state battery, ensuring electronic insulation, and the like.

  In FIG. 1, the positive electrode 250 and the negative electrode 150 are alternately stacked so that the positive electrode coating portion 253 and the negative electrode coating portion 153 overlap, while the positive electrode tab 254 and the negative electrode tab 154 do not overlap each other. The number of electrodes is 5 for the positive electrode 250 and 6 for the negative electrode 150, and the configuration of the stacked secondary battery 1000 is 1 to 10 in parallel.

  The laser beam 5 is irradiated from the upper surface of the stacked body of the stacked secondary battery 1000 along the electrode punching line 6 including the positive electrode tab 254 and the negative electrode tab 154 so that the positive electrode 250 and the negative electrode 150 have the same shape. Punch the electrode body at once. The stacked secondary battery 1000 is completed by mounting and packaging the electrode terminals on the positive electrode tab 254 and the negative electrode tab 154 of the punched electrode body.

  By using the laser beam 5 for punching the electrode body, the end of the electrode is melted, so that bending of the cut end and generation of burrs are small, and an electrical short circuit at the end of the electrode can be prevented. Thereby, the work of preventing the electrode end short circuit after the electrode body is formed becomes unnecessary, and the manufacturing time can be shortened. Further, since the electrodes are punched after laminating the positive electrode 250 and the negative electrode 150, the horizontal alignment of the positive electrode 250 and the negative electrode 150 becomes unnecessary, the alignment mechanism of the manufacturing apparatus can be omitted, and the apparatus can be simplified. Similarly, when a radiation or an electron beam is used instead of a laser beam for punching the electrode body, it is possible to prevent a short circuit at the electrode end and simplify the manufacturing apparatus.

  In the electrode cross section of the electrode body punched separately after the positive electrode 250 and the negative electrode 150 are punched separately and sandwiched between the resin separators, the electrode end portion is greatly bent and burrs are frequently generated. It is considered that the negative electrode 150 is different. On the other hand, in the electrode cross section of the electrode body after punching as in this example, the bending of the end portion is small, the occurrence of burrs is small, and the micro unevenness of the cut portion is substantially the same in the positive electrode 250 and the negative electrode 150. It is thought that there is.

  FIG. 2 shows an embodiment in which a SUS uneven mold is used for punching electrodes. The configurations of the positive electrode and the negative electrode are the same as those in Example 1.

  After the punching die projection 7 having a shape along the electrode punching line 6 is provided on the upper surface of the electrode body and the punching die recess 8 is provided on the lower surface of the electrode body, a load is applied to the punching die projection 7 to punch the electrode body. Since the punching die projection 7 and the punching die recess 8 are made of SUS and have the same material and the same hardness, the end portion of the electrode does not bend in one direction on the convex portion side or the concave portion side of the die. Occurrence is suppressed, and a short circuit of the electrode end can be prevented.

  According to this embodiment, by using a method of punching the electrode body using a metal uneven mold for punching the electrode, the electrode end short-circuit prevention work after punching becomes unnecessary, and the battery manufacturing time can be shortened. This eliminates the need for electrode alignment work and simplifies the manufacturing apparatus.

  In addition, when the manufacturing method according to the present embodiment is applied, when the chips adhering to the mold and the punching blade are analyzed, the active material, the conductive material, the binder applied to the positive electrode coating unit 253 and the negative electrode coating unit 153 are analyzed. The landing material and the insulating material are detected simultaneously.

  FIG. 3 shows an embodiment in which a SUS punching blade and a base plate are used for punching electrodes. The configurations of the positive electrode and the negative electrode are the same as those in Example 1.

  After installing the punching blade 9 on the upper surface of the electrode body and the underlay plate 10 on the lower surface, a load is applied to the punching blade 9 to punch the electrode body. Since the punching blade 9 and the underlay plate 10 are made of the same material and have the same hardness, bending of the end portion and generation of burrs can be suppressed similarly to the second embodiment, and the battery manufacturing time can be shortened and the manufacturing equipment can be simplified.

  Since the base plate 10 is flat, it is considered that the bending of the electrode end cannot be ignored when the number of stacked layers increases, and this method is suitable when the number of stacked layers is relatively small. When the number of stacked batteries is large, punching with the mold of Example 2 is a more suitable method.

5 Laser beam 6 Electrode punching line 7 Punching die convex 8 Punching die concave 9 Punching blade 10 Underlay plate 150 Negative electrode 151 Negative electrode mixture layer 152 Negative electrode collector 153 Negative electrode coating portion 154 Negative electrode tab 250 Positive electrode 251 Positive electrode mixture layer 252 Positive electrode current collector 253 Positive electrode coating part 254 Positive electrode tab 300 Electrolyte layer 1000 Multilayer secondary battery

Claims (6)

Applying a positive electrode mixture layer to the positive electrode current collector to produce a positive electrode so that a positive electrode coated part and a positive electrode uncoated part are formed;
Forming a separator on the positive electrode;
Applying a negative electrode mixture layer to the negative electrode current collector to produce a negative electrode so that a negative electrode coated part and a negative electrode uncoated part are formed;
Forming a separator on the negative electrode;
The positive electrode and the negative electrode are formed so that one electrode coated portion and the other electrode coated portion overlap so that one electrode uncoated portion does not overlap the other electrode coated portion and electrode uncoated portion. Laminating,
Punching out the positive electrode and the negative electrode at a time to produce a positive electrode tab and a negative electrode tab on the uncoated portion of the positive electrode and an uncoated portion of the negative electrode. In the manufacturing method of the lamination type secondary battery of Claim 1,
A method for producing a stacked secondary battery, wherein the positive electrode and the negative electrode are punched out with laser light, radiation, or an electron beam. In the manufacturing method of the lamination type secondary battery of Claim 1,
A method for manufacturing a laminated secondary battery, wherein the positive electrode and the negative electrode are punched out by a punching convex mold and a punching concave mold. In the manufacturing method of the lamination type secondary battery of Claim 3,
A method for manufacturing a laminated secondary battery, wherein the punched convex mold and the punched concave mold have the same material and hardness. In the manufacturing method of the lamination type secondary battery of Claim 1,
A method for manufacturing a stacked secondary battery, wherein the positive electrode and the negative electrode are punched out by a punching blade and an underlay plate. In the manufacturing method of the lamination type secondary battery of Claim 5,
A method for manufacturing a laminated secondary battery, wherein the punching blade and the base plate have the same material and hardness.

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