Electrode group, secondary battery, battery pack, and vehicle

Patent metadata

Field	Value
Publication number	US-12107209-B2
Application number	US-202117462507-A
Country	US
Kind code	B2
Filing date	Aug 31, 2021
Priority date	Mar 15, 2021
Publication date	Oct 1, 2024
Grant date	Oct 1, 2024

Abstract

According to an embodiment, an electrode group is provided. The electrode group includes a positive electrode, and a negative electrode. The negative electrode active material-containing layer includes a facing section which faces the positive electrode active material-containing layer and a non-facing section which does not. A first fluorine-containing coating is formed on a main surface of the negative electrode active material-containing layer in at least a part of the non-facing section. The abundance ratio of fluorine atoms included in the first fluorine-containing coating is in the range of 2.5 atom % to 10 atom %.

First claim

What is claimed is:

1. An electrode group comprising:
a positive electrode comprising a positive electrode current collector and a positive electrode active material-containing layer on the positive electrode current collector;
a negative electrode comprising a negative electrode current collector and a negative electrode active material-containing layer on the negative electrode current collector; and
a separator formed of a synthetic resin nonwoven fabric or a porous film consisting of at least one selected from the group consisting of: polyethylene, polypropylene, cellulose, polyvinylidene fluoride, wherein
an area (NA 1 ) of an orthogonal projection of the negative electrode active material-containing layer to the negative electrode current collector is larger than an area (PA 1 ) of an orthogonal projection of the positive electrode active material-containing layer to the positive electrode current collector,
the negative electrode active material-containing layer comprises a facing section which faces the positive electrode active material-containing layer and a non-facing section which does not face the positive electrode active material-containing layer,
a first fluorine-containing coating is formed on a main surface of the negative electrode active material-containing layer in at least a part of the non-facing section, and
an abundance ratio of fluorine atoms included in the first fluorine-containing coating is in a range of 2.5 atom % to 10 atom %, wherein
a width of the non-facing section is defined by a distance from a side surface of the negative electrode active material-containing layer to a boundary surface between the non-facing section and the facing section in a first direction along an in-plane direction of the negative electrode active material-containing layer, and
the first fluorine-containing coating is formed on the main surface of the negative electrode active material-containing layer in a region extending from the side surface of the negative electrode active material-containing layer to a position at 10% to 150% of the width of the non-facing section toward the facing section along the first direction.

2. The electrode group according to claim 1 , wherein the first fluorine-containing coating is formed on the main surface of the negative electrode active material-containing layer in a proportion of 50% or more with respect to an area (NA 2 ) of the non-facing section to the negative electrode current collector.

3. The electrode group according to claim 1 , wherein
a second fluorine-containing coating is formed on the main surface of the negative electrode active material-containing layer in at least a part of the facing section, and
an abundance ratio of fluorine atoms included in the second fluorine-containing coating is in a range of 0.1 atom % or more and less than 2.5 atom %.

4. The electrode group according to claim 1 , wherein an abundance ratio of fluorine atoms included in the first fluorine-containing coating is in a range of 2.5 atom % to 6.0 atom %.

5. The electrode group according to claim 1 , wherein a ratio (NA 1 /PA 1 ) of the area (NA 1 ) to the area (PA 1 ) is 1.00<NA 1 /PA 1 ≤1.20.

6. The electrode group according to claim 1 , wherein
the negative electrode active material-containing layer comprises a negative electrode active material, and
the negative electrode active material comprises at least one titanium-containing oxide selected from the group consisting of lithium titanate having a ramsdellite structure, lithium titanate having a spinel structure, monoclinic titanium dioxide, anatase-type titanium dioxide, rutile-type titanium dioxide, hollandite-type titanium composite oxide, orthorhombic titanium-containing composite oxide, and monoclinic niobium titanium composite oxide.

7. The electrode group according to claim 6 , wherein
the negative electrode active material comprises the monoclinic niobium titanium composite oxide,
the monoclinic niobium titanium composite oxide is at least one selected from the group consisting of composite oxides represented by a general formula of Li x Ti 1−y M1 y Nb 2-z M2 z O 7+δ and composite oxides represented by a general formula of Li x Ti 1−y M3 y+z Nb 2−z O 7−δ ,
M1 is at least one selected from the group consisting of Zr, Si, and Sn, M2 is at least one selected from the group consisting of V, Ta, and Bi, and M3 is at least one selected from the group consisting of Mg, Fe, Ni, Co, W, Ta, and Mo, and
x satisfies 0≤x≤5, y satisfies 0≤y<1, z satisfies 0≤z<2, and δ satisfies −0.3≤δ≤0.3.

8. A secondary battery comprising the electrode group according to claim 1 , and an electrolyte.

9. A battery pack comprising the secondary battery according to claim 8 .

10. The battery pack according to claim 9 , further comprising:
an external power distribution terminal; and
a protective circuit.

11. The battery pack according to claim 9 , comprising a plurality of the secondary battery,
wherein the secondary batteries are electrically connected in series, in parallel, or in a combination of in series and in parallel.

12. A vehicle comprising the battery pack according to claim 9 .

13. The vehicle according to claim 12 , comprising a mechanism configured to convert kinetic energy of the vehicle to regenerative energy.

14. The electrode group according to claim 1 , wherein the first fluorine-containing coating is formed on the main surface of the negative electrode active material-containing layer in only a part or an entire region of the non-facing section.

15. The electrode group according to claim 1 , wherein
the first fluorine-containing coating is formed on the main surface of the negative electrode active material-containing layer in a region extending from the side surface of the negative electrode active material-containing layer to a position at 10% to 100% of the width of the non-facing section toward the facing section along the first direction.

Assignees

• Toshiba Kk

Inventors

• Yamashita Yasunobu
• Sasakawa Tetsuya
• Harada Yasuhiro
• Takami Norio
• Matsuno Shinsuke

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M10/058

  Construction or manufacture · CPC title

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M50/249

  specially adapted for aircraft or vehicles, e.g. cars or trains (constructional details of batteries specially adapted for electric vehicles B60L50/64) · CPC title

• H01M2004/027

  Negative electrodes · CPC title