Secondary battery-use anode and method of manufacturing the same, secondary battery and method of manufacturing the same, battery pack, electric vehicle, electric power storage system, electric power tool, and electronic apparatus

Patent metadata

Field	Value
Publication number	US-11088359-B2
Application number	US-201615575117-A
Country	US
Kind code	B2
Filing date	Jul 26, 2016
Priority date	Aug 10, 2015
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

A secondary battery includes a cathode, an anode, and an electrolytic solution. The anode includes a first anode active material, a second anode active material, and an anode binder. The first anode active material includes a first central portion and a first coating portion. The first central portion includes a material that includes silicon as a constituent element, and the first coating portion is provided on a surface of the first central portion and includes one or both of a polyacrylate salt and a carboxymethylcellulose salt. The second anode active material includes a material that includes carbon as a constituent element. The anode binder includes one or more of polyvinylidene fluoride, polyimide, and aramid.

First claim

What is claimed is:

1. A secondary battery comprising:
a cathode, an anode, and an electrolytic solution,
the anode including a first anode active material, a second anode active material, and an anode binder,
the first anode active material including a first central portion and a first coating portion, the first central portion including a material that includes silicon as a constituent element, and the first coating portion being directly disposed on a surface of the first central portion and including one or both of a polyacrylate salt and a carboxymethylcellulose salt,
the second anode active material including a material that includes carbon as a constituent element, and
the anode binder including one or more of polyvinylidene fluoride, polyimide, and aramid,
wherein:
a mixing ratio of the first anode active material is smaller than a mixing ratio of the second anode active material,
each of the first anode active material and the second anode active material is in a form of a plurality of particles,
a ratio D1/D2 of a median diameter D1 (D50) of the first anode active material to a median diameter D2 (D50) of the second anode active material is in a range from 0.05 to 2,
the anode includes an anode active material layer including the first anode active material, the second anode active material, and the anode binder and having a plurality of pores, and
a pore diameter at which a change rate of a mercury intrusion amount into the plurality of pores exhibits a peak in measurement of the change rate of the mercury intrusion amount with use of a mercury intrusion technique is in a range from 0.5 μm to 5 μm.

2. The secondary battery according to claim 1 , wherein
the polyacrylate salt included in the first coating portion includes one or more of lithium polyacrylate, sodium polyacrylate, and potassium polyacrylate, and
the carboxymethylcellulose salt included in the first coating portion includes one or more of carboxymethylcellulose lithium, carboxymethylcellulose sodium, and carboxymethylcellulose potassium.

3. The secondary battery according to claim 1 , wherein a specific surface area of the first anode active material is in a range from 0.1 m 2 /g to 10 m 2 /g.

4. The secondary battery according to claim 3 , wherein the specific surface area of the first anode active material is in a range from 0.5 m 2 /g to 1 m 2 /g.

5. The secondary battery according to claim 1 , wherein a ratio (W1) of a weight of the first coating portion to a weight of the first central portion is less than 20 wt %.

6. The secondary battery according to claim 1 , wherein the second anode active material includes a second central portion and a second coating portion, the second central portion including a material that includes the carbon as a constituent element, and the second coating portion being directly disposed on a surface of the second central portion and including one or both of a polyacrylate salt and a carboxymethylcellulose salt.

7. The secondary battery according to claim 6 , wherein
the polyacrylate salt included in the second coating portion includes one or more of lithium polyacrylate, sodium polyacrylate, and potassium polyacrylate, and
the carboxymethylcellulose salt included in the second coating portion includes one or more of carboxymethylcellulose lithium, carboxymethylcellulose sodium, and carboxymethylcellulose potassium.

8. The secondary battery according to claim 6 , wherein
a ratio (W2) of a weight of one or both of the polyacrylate salt and the carboxymethylcellulose salt included in the anode active material layer to a weight of the anode active material layer is in a range from 0.1 wt % to 4.5 wt %.

9. The secondary battery according to claim 6 , wherein a thickness of each of the first coating portion and the second coating portion is less than 1 μm.

10. The secondary battery according to claim 6 , wherein a coverage of each of the first coating portion and the second coating portion is 50% or more.

11. The secondary battery according to claim 6 , wherein
a thickness of the first coating portion is smaller than a thickness of the second coating portion, or
the thickness of the second coating portion is smaller than the thickness of the first coating portion.

12. The secondary battery according to claim 1 , wherein the anode further includes a hydrogen binding buffer that includes one or more of a borate salt, a phosphate salt, and ethanolamine.

13. The secondary battery according to claim 1 , wherein the anode includes one or more of a silane coupling agent including an amino group, a silane coupling agent including sulfur as a constituent element, and a silane coupling agent including fluorine as a constituent element.

14. The secondary battery according to claim 1 , wherein the secondary battery is a lithium-ion secondary battery.

15. The secondary battery according to claim 1 , wherein the second anode active material comprises one or more of graphite, pyrolytic carbons, cokes, glassy carbon fibers, an organic polymer compound fired body, activated carbon, and carbon blacks.

16. The secondary battery according to claim 1 , wherein the first anode active material comprises SiO v (0<v≤2).

17. The secondary battery according to claim 1 , wherein the first central portion is a silicon based material having a mean particle diameter of 1 μm to 10 μm and the second anode active material has a mean particle diameter of 5 μm to 40 μm.

18. The secondary battery according to claim 1 , wherein the anode further includes a third anode active material comprising a metal based material, wherein the metal based material comprises one or more of magnesium, boron, aluminum, gallium, indium, silicon, germanium, tin, lead, bismuth, cadmium, silver, zinc, hafnium, zirconium, yttrium, palladium, and platinum.

19. The secondary battery according to claim 1 , wherein the first central portion consists essentially of silicon, an alloy of silicon, or a combination thereof.

20. The secondary battery according to claim 1 , wherein the first anode active material comprises one or more of Si, SiB 4 , SiB 6 , Mg 2 Si, Ni 2 Si, TiSi 2 , MoSi 2 , CoSi 2 , NiSi 2 , CaSi 2 , CrSi 2 , Cu 2 Si, FeSi 2 , MnSi 2 , NbSi 2 , TaSi 2 , VSi 2 , WSi 2 , ZnSi 2 , SiC, Si 3 N 4 , Si 2 N 2 O, and LiSiO.

21. The secondary battery according to claim 1 , wherein the first coating portion is in contact with the surface of the first central portion.

22. The secondary battery according to claim 1 , wherein a composition of the first anode active material is different than a composition of the second anode active material.

23. The secondary battery according to claim 1 , wherein a coverage of the first coating portion is 50% to less than 100%.

24. A secondary battery-use anode comprising:
a first anode active material, a second anode active material, and an anode binder,
the first anode active material including a first central portion and a first coating portion, the first central portion including a material that includes silicon as a constituent element, and the first coating portion being directly disposed on a surface of the first central portion and including one or both of a polyacrylate salt and a carboxymethylcellulose salt,
the second anode active material including a material that includes carbon as a constituent element, and
the anode binder including one or more of polyvinylidene fluoride, polyimide, and aramid,
wherein:
a mixing ratio of th

Assignees

• Murata Manufacturing Co

Inventors

• Koike Yosuke
• Nagata Yoshihide
• Takada Kazuaki

Classifications

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/364

  as mixtures · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M10/0525

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

• H01M4/366

  as layered products · CPC title