Lithium secondary battery incuding lithium-ion conductive nonaqueous electrolyte

Patent metadata

Field	Value
Publication number	US-2019280340-A1
Application number	US-201916260134-A
Country	US
Kind code	A1
Filing date	Jan 29, 2019
Priority date	Mar 9, 2018
Publication date	Sep 12, 2019
Grant date	—

Abstract

A lithium secondary battery includes a wound electrode group and a lithium-ion conductive nonaqueous electrolyte. The wound electrode group includes a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode. The negative electrode includes a negative electrode current collector. The negative electrode current collector includes: a layer having a first surface facing outward of the winding of the electrode group and a second surface facing inward of the winding of the electrode group; first protrusions protruding from the first surface; and second protrusions protruding from the second surface. Lithium metal is deposited on the first surface and the second surface by charging. A second average height of the second protrusions is higher than a first average height of the first protrusions.

First claim

What is claimed is:

1 . A lithium secondary battery comprising:
a wound electrode group including a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode; and a lithium-ion conductive nonaqueous electrolyte, wherein the negative electrode includes a negative electrode current collector; the negative electrode current collector includes: a layer having a first surface facing outward of the winding of the electrode group and a second surface facing inward of the winding of the electrode group; first protrusions protruding from the first surface; and second protrusions protruding from the second surface; lithium metal is deposited on the first surface and the second surface by charging; and a second average height of the second protrusions is higher than a first average height of the first protrusions.

2 . The lithium secondary battery according to claim 1 , wherein a difference between the second average height and the first average height is 3% or more and 50% or less of the first average height.

3 . The lithium secondary battery according to claim 1 , wherein the layer includes copper foil or copper alloy foil.

4 . The lithium secondary battery according to claim 1 , wherein
the first protrusions and the second protrusions are each in contact with the separator; and the lithium metal is deposited in a space between the negative electrode current collector and the separator by charging.

5 . The lithium secondary battery according to claim 1 , wherein
the first protrusions are made of a material different from that of the layer; and the second protrusions are made of a material different from that of the layer.

6 . The lithium secondary battery according to claim 1 , wherein
the first protrusions and the second protrusions are each made of a resin material.

7 . The lithium secondary battery according to claim 1 , wherein
the layer, the first protrusions, and the second protrusions are integrally made of the same material.

8 . The lithium secondary battery according to claim 1 , wherein
a projection shape of each of the first protrusions on the first surface is a strip shape or a line shape; a projection shape of each of the second protrusions on the second surface is a strip shape or a line shape; in the first surface, a minimum clearance between two adjacent first protrusions among the first protrusions is larger than a maximum width of the two adjacent first protrusions; and in the second surface, a minimum clearance between two adjacent second protrusions among the second protrusions is larger than a maximum width of the two adjacent second protrusions.

9 . The lithium secondary battery according to claim 1 , wherein
a total area of projection of the first protrusions on the first surface is 0.2% or more and 70% or less of the area of the first surface; and a total area of projection of the second protrusions on the second surface is 0.2% or more and 70% or less of the area of the second surface.

10 . The lithium secondary battery according to claim 1 , wherein the second average height is 15 μm or more and 120 μm or less.

11 . The lithium secondary battery according to claim 1 , wherein
in each of the first surface and the second surface of the layer, when a direction perpendicular to the winding axis of the electrode group is defined as a length direction, and a direction parallel to the winding axis is defined as a width direction, at least one band-shaped first region where no first protrusions are formed is disposed on the first surface along at least the length direction or the width direction, and at least one band-shaped second region where no second protrusions are formed is disposed on the second surface along at least the length direction or the width direction.

12 . The lithium secondary battery according to claim 1 , wherein
the nonaqueous electrolyte includes a lithium ion and an anion; and the anion includes at least one selected from the group consisting of PF 6 − , anions of imides, and anions of oxalate complexes.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Kano Akira
• Miyamae Ryohei
• Isii Kiyohiro
• Sakamoto Junichi

Classifications

• H01M10/0587 Primary

  of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/661

  Metal or alloys, e.g. alloy coatings (H01M4/669 take precedence) · CPC title