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EP-4135112-B1 - METHOD OF MANUFACTURING BATTERY

EP4135112B1EP 4135112 B1EP4135112 B1EP 4135112B1EP-4135112-B1

Inventors

  • IKESHITA, Kazuya
  • FURUKOJI, Yoshiyuki

Dates

Publication Date
20260506
Application Date
20220804

Claims (8)

  1. A method of manufacturing a battery (2) including a wound electrode assembly wherein a first separator (31), a negative electrode plate (22), a second separator (32), and a positive electrode plate (21) are wound together, the method comprising the steps of: (A) suction-attaching the first separator (31) and the second separator (32) to a winding core (140), with the first separator (31) and the second separator (32) being stacked on each other; and (B) winding the first separator (31) and the second separator (32) around the winding core (140), wherein: each of the first separator (31) and the second separator (32) includes a porous substrate layer (33) made of resin, and at least one surface layer (34) formed on at least one surface of the substrate layer (33).
  2. The method according to claim 1, wherein: each of the first separator (31) and the second separator (32) includes a plurality of the surface layers (34) respectively formed on both surfaces of the substrate layer (33); and each of the surface layers (34) comprises a three-dimensional network structure containing polyvinylidene fluoride (PVdF).
  3. The method according to claim 2, wherein in each of the first separator (31) and the second separator (32), each of the surface layers (34) contains the PVdF in a mass percentage of greater than or equal to 10%.
  4. The method according to claim 2 or 3, wherein in each of the first separator (31) and the second separator (32), the surface layer (34) contains inorganic particles.
  5. The method according to claim 1, wherein: each of the first separator (31) and the second separator (32) includes the surface layer (34) formed only on one surface of the substrate layer (33); the surface layer (34) contains inorganic particles and a binder; the surface layer (34) contains the inorganic particles in a mass percentage of greater than or equal to 90%; and in step (B), the first separator (31) and the second separator (32) are wound around the winding core (140) in such an orientation that the substrate layer (33) of the first separator (31) and the substrate layer (33) of the second separator (32) face each other.
  6. The method according to any one of claims 1 to 5, wherein in step (B), the first separator (31) and the second separator (32) are pressed by a jig (152) including a plurality of protrusions (152a) formed on its surface.
  7. The method according to any one of claims 1 to 5, wherein: each of the surface layer (34) of the first separator (31) and the surface layer (34) of the second separator (32) is an adhesive layer; and in step (B), the first separator (31) and the second separator (32) are pressed by a jig (152) including a plurality of protrusions (152a) formed on its surface.
  8. The method according to any one of claims 1 to 7, wherein each of the first separator (31) and the second separator (32) has a width of greater than or equal to 25 cm.

Description

The present invention relates to a method of manufacturing a battery. BACKGROUND JP 2009-193750 A discloses a method of manufacturing an electrode plate group for a non-aqueous electrolyte secondary battery in which a strip-shaped positive electrode plate and a strip-shaped negative electrode plate are spirally wound with two sheets of separator being stacked together alternately. In the manufacturing method disclosed in the publication, tip parts of the separators are stuck to a winding core while being pressed against the winding core, and the positive electrode plate and the negative electrode plate are sandwiched and wound into a spiral shape. US 2017/162913 A1 discloses a spirally-wound electrode, in a first region, short sides of first and second separator sheets on an inner side are aligned with each other. In a second region, a negative electrode sheet, the first separator sheet, a positive electrode sheet, and the second separator sheet are arranged from an inner side toward an outer side in a radial direction. The second region extends from a position where short sides of the negative and positive electrode sheets on the inner side are aligned with each other in a same phase to a short side of the positive electrode sheet on an outer side. In a third region, the negative electrode sheet, and the first and second separator sheets are arranged from the inner side toward the outer side in the radial direction. The third region extends to a short side of the negative electrode sheet on the outer side. From JP 2020-009769 A, a core manufacturing mechanism for manufacturing a core used for winding a strip-shaped element film to form a battery or a capacitor is known. US 2018/047962 A1 discloses a separator for a non-aqueous secondary battery, the separator including: a porous substrate; and an adhesive porous layer provided on one or both sides of the porous substrate and including a polyvinylidene fluoride-based resin, the adhesive porous layer would exhibit a ratio of an area intensity of a β-phase-crystal-derived peak of the polyvinylidene fluoride-based resin to a sum of an area intensity of an α-phase-crystal-derived peak of the polyvinylidene fluoride-based resin and the area intensity of the β-phase-crystal-derived peak of the polyvinylidene fluoride-based resin of from 10% to 100% when an x-ray diffraction spectrum is obtained by performing measurement by an x-ray diffraction method. A method for manufacturing a battery as disclosed by US 2014/302367 A1 comprises winding a separator to a winding core, and forming an area in which the separator is overlapped in equal to or more than two layers of the separator, joining the two layers mutually in pressure contact by pressing a projecting portion formed in a jig to the overlapped area, after the step of the joining, providing a positive electrode plate and a negative electrode plate to the winding core, and winding into a spiral form the positive electrode plate and the negative electrode plate interposing the separator therebetween, and after the step of the winding, forming a spiral electrode assembly by removing the winding core from a winding body wound into the spiral form. US 2015/086821 A1 finally discloses a flat wound secondary battery that has a wound electrode body including a positive electrode and a negative electrode that are wound flat around a shaft core with a separator interposed between the electrodes, and a battery container that contains the wound electrode body. The shaft core includes a wound resin sheet having higher flexural rigidity than the positive electrode, the negative electrode, and the separator. The shaft core includes an innermost portion that forms the innermost periphery of the shaft core and an extended portion to a winding terminal end from the innermost portion. The separator includes a bonded portion to the extended portion and a separator winding portion that winds only the separator at least one turn around the shaft core. SUMMARY In such a manufacturing method, it is sometimes the case that the separator used in the wound electrode assembly is a separator that includes a substrate layer and a substrate layer. Since such a separator including a substrate layer and a surface layer is rather expensive, it is possible to contribute to improvement in productivity by reducing the number of separators that are disposed of because of misalignment in winding or the like. Accordingly, the present inventors believe that it is desired to solve problems such as misalignment in winding in a simpler method, to improve productivity. A method of manufacturing a battery including a wound electrode assembly is disclosed in the present disclosure. The method includes the following steps. Step (A): suction-attaching a first separator and a second separator to a winding core, with the first separator and the second separator being stacked on each other. Step (B): winding the first separator and the second separator around the