Electric storage device and electric storage apparatus

• US 9,793,526 B2
• Filed: 03/27/2014
• Issued: 10/17/2017
• Est. Priority Date: 03/29/2013
• Status: Active Grant

• Current Assignee: GS Yuasa International Ltd. (GS Yuasa Corporation)
• Original Assignee: GS Yuasa International Ltd. (GS Yuasa Corporation)
• Inventors: Miyazaki, Akihiko
• Primary Examiner(s): Slifka, Sarah A
• Assistant Examiner(s): Ohara, Brian
• Application Number:
  US14/227,416
• Publication Number:
  US 20140295245A1
• Time in Patent Office: 1,300 Days
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/0587 of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
• CPC Class Codes: H01M 50/406 Moulding; Embossing; Cutting
• CPC Class Codes: H01M 50/414 Synthetic resins, e.g. thermoplastics or thermosetting resins
• CPC Class Codes: H01M 50/417 Polyolefins
• CPC Class Codes: H01M 50/434 Ceramics
• CPC Class Codes: H01M 50/446 Composite material consisting of a mixture of organic and inorganic materials
• CPC Class Codes: H01M 50/451 comprising layers of only organic material and layers containing inorganic material
• CPC Class Codes: H01M 50/46 Separators, membranes or diaphragms characterised by their combination with electrodes
• CPC Class Codes: H01M 50/489 Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

An electric storage device includes: a container; an electrode assembly contained in the container, the electrode assembly including a positive electrode having a positive electrode substrate and a positive electrode active material layer that is formed on the positive electrode substrate and contains a positive electrode active material, a negative electrode having a negative electrode substrate and a negative electrode active material layer that is formed on the negative electrode substrate and contains a negative electrode active material, and a separator interposed between the positive and negative electrodes; and an electrolyte contained in the container, wherein the separator is configured such that a stress caused at a specific compressed depth in the separator, which corresponds to 5% of the thickness of the negative electrode active material layer, is 0.5 MPa or more and 14 MPa or less. An electric storage apparatus includes a plurality of electric storage devices described above.

Claims

1. A lithium ion secondary battery cell comprising:

a container;

an electrode assembly contained in the container, the electrode assembly comprising;

a positive electrode comprising a positive electrode substrate and a positive electrode active material layer formed on the positive electrode substrate, the positive electrode active material layer containing a positive electrode active material comprising a lithium composite oxide,

a negative electrode comprising a negative electrode substrate and a negative electrode active material layer formed on the negative electrode substrate, the negative electrode active material containing a negative electrode active material, and

a separator interposed between the positive electrode and the negative electrode; and

an electrolyte contained in the container, the electrolyte comprising a lithium salt,

wherein the separator is configured such that a stress that is caused at a specific compressed depth in the separator, which corresponds to 5% of the thickness of the negative electrode active material, is 0.5 MPa or more and 14 MPa or less;

the negative electrode active material contains hard carbon; and

a ratio of a volume of the electrolyte with respect to a void volume of the lithium ion secondary battery cell is 120% or more and 180% or less.

2. The lithium ion secondary battery cell according to claim 1, wherein the stress caused at the specific compressed depth in the separator is 1 MPa or more and 10 MPa or less.

3. The lithium ion secondary battery cell according to claim 1, wherein the stress caused at the specific compressed depth in the separator is 3 MPa or more and 5 MPa or less.

4. The lithium ion secondary battery cell according to claim 1, wherein the separator has a thickness of 15 μ

m or more and 25 μ

m or less.

5. The lithium ion secondary battery cell according to claim 1, wherein the separator has a thickness of 18 μ

m or more and 22 μ

m or less.

6. The lithium ion secondary battery cell according to claim 1, wherein the separator comprises a separator substrate and an inorganic layer formed on the separator substrate, and

a ratio of the thickness of the inorganic layer to the thickness of the separator substrate is 0.2 or more and less than 1.

7. The lithium ion secondary battery cell according to claim 6, wherein the inorganic layer has a peeling strength of 5 gf or more and 80 gf or less.

8. The lithium ion secondary battery cell according to claim 1, wherein the separator has a restoration rate by a loading/unloading test of 2.8% or more.

9. The lithium ion secondary battery cell according to claim 1, wherein the separator has an air resistance of 30 sec/100 cc or more and 150 sec/100 cc or less.

10. An electric storage apparatus comprising a plurality of lithium ion secondary battery cells according to claim 1.

11. An electric storage apparatus comprising a plurality of lithium ion secondary battery cells according to claim 2.

12. An electric storage apparatus comprising a plurality of lithium ion secondary battery cells according to claim 4.

13. An electric storage apparatus comprising a plurality of lithium ion secondary battery cells according to claim 6.

14. The lithium ion secondary battery cell according to claim 1, wherein the negative electrode active material has a particle size of 3 μ

m or more and 6 μ

m or less.

15. The lithium ion secondary battery cell according to claim 1, wherein the negative electrode active material has a particle size of 3 μ

m or more and 5 μ

m or less.