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US-20260128431-A1 - LITHIUM SECONDARY BATTERY

US20260128431A1US 20260128431 A1US20260128431 A1US 20260128431A1US-20260128431-A1

Abstract

In some embodiments, a lithium secondary battery is provied. The battery can include a laminate in which positive electrodes and negative electrodes are laminated in a lamination direction. A separator can be interposed between the positive electrode and the negative electrode. A first current collector can be present, the first current collector comprising a pair of conductive layers and a resin layer. The pair of conductive layers can sandwich the resin layer. The first current collector including a first end part. A first electrode tab electrically connected to the first end part can be present. A sealed container can be present including a sealing part. The sealed container can be configured to sandwich the first insulating part of the first electrode tab at the sealing part and to allow a part of the first electrode tab to be taken out to an outside of the sealed container.

Inventors

  • Minoru Miyake
  • Gosuke OYAMA
  • Ken Ogata

Assignees

  • TERAWATT TECHNOLOGY K.K.

Dates

Publication Date
20260507
Application Date
20251218

Claims (17)

  1. 1 . A lithium secondary battery comprising: a laminate in which a plurality of positive electrodes and a plurality of negative electrodes are laminated in a lamination direction, a separator being interposed between the positive electrode and the negative electrode, one of the positive electrode and the negative electrode including a first current collector, the first current collector comprising a pair of conductive layers and a resin layer, the pair of conductive layers sandwiching the resin layer, the first current collector including a first end part, the first end part extending in a first direction different from the lamination direction; a first electrode tab electrically connected to the first end part, the first electrode tab including a first bonding mark and a first insulating part, the first bonding mark being formed by bonding to the first end part, the first insulating part being disposed apart from the first bonding mark in the first direction, the first insulating part being covered with an insulating material; and a sealed container including a sealing part, the sealed container being configured, while enclosing the laminate inside the sealing part, to sandwich the first insulating part of the first electrode tab at the sealing part and to allow a part of the first electrode tab to be taken out to an outside of the sealed container.
  2. 2 . The lithium secondary battery according to claim 1 , wherein the first bonding mark in the first end part is provided 2 mm or more inward from an outer edge of the first end part in the first direction.
  3. 3 . The lithium secondary battery according to claim 1 , wherein the first bonding mark in the first end part is provided 2.5 mm or more inward from an outer edge of the first end part in the first direction.
  4. 4 . The lithium secondary battery according to claim 1 , wherein in a case where a total number of the first current collectors included in the laminate is denoted as X and a distance between the first bonding mark in the first end part and an outer edge of the first end part in the first direction is denoted as Y, a relationship of Y>0.048X+1.3 is satisfied.
  5. 5 . The lithium secondary battery according to claim 4 , wherein the X is 10 or more.
  6. 6 . The lithium secondary battery according to claim 1 , wherein the first bonding mark is a welding mark.
  7. 7 . The lithium secondary battery according to claim 6 , wherein the first bonding mark includes a region in which the pair of conductive layers are integrated with each other in a cross section in the lamination direction.
  8. 8 . The lithium secondary battery according to claim 1 , wherein the first end part and the first electrode tab are bonded to each other with a metal sheet being interposed between the first end part and the first electrode tab.
  9. 9 . The lithium secondary battery according to claim 8 , wherein the first bonding mark is a welding mark.
  10. 10 . The lithium secondary battery according to claim 9 , wherein the first bonding mark includes a region in which the pair of conductive layers and the metal sheet are integrated over a plurality of layers in a cross section in the lamination direction.
  11. 11 . The lithium secondary battery according to claim 8 , wherein the first end part has a preliminary bonding mark formed by bonding to the metal sheet, and the preliminary bonding mark is provided at a position different from the first bonding mark in a case of being viewed from the lamination direction.
  12. 12 . The lithium secondary battery according to claim 1 , wherein the first current collector is a negative electrode current collector of the negative electrode, and the first electrode tab is a negative electrode tab that is connected to the negative electrode current collector.
  13. 13 . The lithium secondary battery according to claim 12 , wherein the sealed container is formed of an aluminum laminate film.
  14. 14 . The lithium secondary battery according to claim 1 , wherein the other of the positive electrode and the negative electrode includes a second current collector, the second current collector comprising a pair of conductive layers and a resin layer, the pair of conductive layers sandwiching the resin layer, the second current collector including a second end part, the second end part extending in a second direction different from the lamination direction.
  15. 15 . The lithium secondary battery according to claim 14 , further comprising a second electrode tab electrically connected to the second end part, wherein the second electrode tab includes a second bonding mark and a second insulating part, the second bonding mark being formed by bonding to the second end part, the second insulating part being disposed apart from the second bonding mark in the second direction, the second insulating part being covered with an insulating material, and wherein the sealed container is configured to sandwich the second insulating part of the second electrode tab at the sealing part and to allow a part of the second electrode tab to be taken out to the outside of the sealed container.
  16. 16 . The lithium secondary battery according to claim 14 , wherein the first direction and the second direction are the same direction.
  17. 17 . The lithium secondary battery according to claim 14 , wherein the first direction and the second direction are directions different from each other.

Description

CROSS-REFERENCE TO RELATED APPLICATION The present application claims priority under 35 U.S.C. § 119 to PCT Application No. PCT/JP 2023/022782 filed on Jun. 20, 2023, the entire contents of which are incorporated herein by reference. BACKGROUND Field An exemplary embodiment according to the present disclosure relates to a lithium secondary battery. Description of Related Art JPH11-102711 A discloses that the safety of a battery cell is improved by using a current collector in which a metal layer is formed on both surfaces of a resin film. In the resin film, the front and back of the film are separated by a resin layer having insulating properties, and thus electrical conduction cannot be obtained. Therefore, in a case of connecting an electrode tab for leading out a wiring line and an electrode film, conduction cannot be obtained between the front and back of the electrode and between a plurality of the electrodes and a plurality of the electrode tabs. In this regard, JP2013-016321 A discloses that a plurality of current collectors is folded and then laminated on each metal layer in order to connect each metal layer separated by a resin layer to an electrode tab for leading out a wiring line. SUMMARY In one exemplary embodiment of the present disclosure, there is provided a lithium secondary battery including: a laminate in which a plurality of positive electrodes and a plurality of negative electrodes are laminated in a lamination direction, a separator being interposed between the positive electrode and the negative electrode, one of the positive electrode and the negative electrode including a first current collector, the first current collector comprising a pair of conductive layers and a resin layer, the pair of conductive layers sandwiching the resin layer, the first current collector including a first end part, the first end part extending in a first direction different from the lamination direction; a first electrode tab electrically connected to the first end part, the first electrode tab including a first bonding mark and a first insulating part, the first bonding mark being formed by bonding to the first end part, the first insulating part being disposed apart from the first bonding mark in the first direction, the first insulating part being covered with an insulating material; and a sealed container including a sealing part, the sealed container being configured, while enclosing the laminate inside the sealing part, to sandwich the first insulating part of the first electrode tab at the sealing part and to allow a part of the first electrode tab to be taken out to an outside of the sealed container. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a plan view for an explanatory description of a configuration example of a secondary battery 1. FIG. 2 is an exploded perspective view for an explanatory description of a configuration example of a laminate ST. FIG. 3 is a perspective view illustrating an example of a negative electrode 10. FIG. 4 is a perspective view illustrating an example of a positive electrode 30. FIG. 5 is a view for an explanatory description of a bonding state of a negative electrode tab 40, a negative electrode end part P, and a metal sheet M1. FIG. 6 is a view illustrating a cross section of a first bonding mark W1. FIG. 7 is a flowchart illustrating an example of the present manufacturing method. FIG. 8A is a view for an explanatory description of a step ST1. FIG. 8B is a view for an explanatory description of the step ST1. FIG. 9A is a view for an explanatory description of a step ST2. FIG. 9B is a view for an explanatory description of the step ST2. FIG. 9C is a view for an explanatory description of the step ST2. FIG. 9D is a view for an explanatory description of the step ST2. FIG. 10 is a view for an explanatory description of a step ST3. FIG. 11A is a perspective view illustrating another example of the negative electrode 10. FIG. 11B is a perspective view illustrating another example of the negative electrode 10. FIG. 11C is a perspective view illustrating another example of the negative electrode 10. FIG. 12 is a perspective view illustrating another example of the positive electrode 30. FIG. 13 is a perspective view for an explanatory description of another lamination example of the negative electrode 10. FIG. 14 is a perspective view for an explanatory description of another lamination example of the negative electrode 10. FIG. 15 is a view illustrating the results of Experiment 1. FIG. 16A is an example of a case where the metal material has protruded in Experiment 1. FIG. 16B is an example of a case where the metal material has not protruded in Experiment 1. FIG. 17 is a view illustrating the results of Experiment 2. DETAILED DESCRIPTION Hereinafter, each embodiment according to the present disclosure will be described. In one exemplary embodiment, there is provided a lithium secondary battery including: a laminate in which a plurality of positive electrodes and a plura