Positive electrode for secondary batteries, and secondary battery

Patent metadata

Field	Value
Publication number	US-2022149385-A1
Application number	US-202217585919-A
Country	US
Kind code	A1
Filing date	Jan 27, 2022
Priority date	Jul 27, 2017
Publication date	May 12, 2022
Grant date	—

Abstract

This positive electrode for secondary batteries is provided with: a positive electrode collector which has a plurality of recesses and projections in the surface; an intermediate layer which is provided on the surface of the positive electrode collector having the recesses and projections; and a positive electrode mixture layer which is provided on the intermediate layer and contains a positive electrode active material. This positive electrode for secondary batteries is configured such that: the intermediate layer contains conductive material particles and inorganic material particles that have a higher resistance than the positive electrode active material; and both the ratio of the central particle diameter of the conductive material particles to the average depth of the recesses and projections of the positive electrode collector and the ratio of the central particle diameter of the inorganic material particles to the average depth of the recesses and projections of the positive electrode collector are 5:6 or less.

First claim

1 . A secondary battery positive electrode, comprising:
a positive electrode current collector having a plurality of irregularities on a surface thereof; an intermediate layer provided on the irregularities of the positive electrode current collector; and a positive electrode mixture layer provided on the intermediate layer and including a positive electrode active material, wherein the intermediate layer includes inorganic material particles having higher resistance than the positive electrode active material, and an average depth of the irregularities of the positive electrode current collector is 0.6 μm or more, and at least one of projections of the irregularities of the positive electrode current collector penetrates an interface between the intermediate layer and the positive electrode mixture layer and projects into the positive electrode mixture layer.

2 . The secondary battery positive electrode according to claim 1 , wherein the average depth of the irregularities of the positive electrode current collector is 2.0 μm or less.

3 . The secondary battery positive electrode according to claim 1 , wherein a ratio of a median particle diameter of the inorganic material particles to the average depth of the irregularities of the positive electrode current collector is 5:20 or more and 5:6 or less.

4 . The secondary battery positive electrode according to claim 1 , wherein the intermediate layer consists only of the inorganic material particles and a binder.

5 . The secondary battery positive electrode according to claim 1 , wherein in a cross section of the positive electrode current collector, a length of recesses of the positive electrode current collector which are in contact with the intermediate layer is 0.8 or more times and 1.8 or less times a length of projections of the positive electrode current collector which are in contact with the positive electrode mixture layer.

6 . The secondary battery positive electrode according to claim 1 , wherein the median particle diameter of the inorganic material particles is 0.2 μm or more and 1.0 μm or less.

7 . The secondary battery positive electrode according to claim 1 , wherein
the inorganic material particles have a resistivity of 10 12 Ωcm or more, and the inorganic material particles are at least one of the group consisting of metal oxide particles, metal nitride particles, metal fluoride particles, and insulating magnetic particles.

8 . A secondary battery, comprising:
the positive electrode according to claim 1 ; a negative electrode; and an electrolyte.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Oura Yuji
• Shiozaki Tomoki
• Takezawa Hideharu

Classifications

• H01M4/13

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/70

  characterised by shape or form · CPC title

• H01M4/667 Primary

  in the form of layers, e.g. coatings · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title