Densified battery electrodes with electrode parts having different porosities and methods thereof

Patent metadata

Field	Value
Publication number	US-11594718-B2
Application number	US-202016883661-A
Country	US
Kind code	B2
Filing date	May 26, 2020
Priority date	May 23, 2019
Publication date	Feb 28, 2023
Grant date	Feb 28, 2023

Abstract

In an aspect, a Li-ion cell may comprise a densified electrode exhibiting an areal capacity loading of more than about 4 mAh/cm 2 . For example, the densified electrode may a first electrode part arranged on a current collector and a second electrode part on top of the first electrode part, the second electrode part of the at least one densified electrode having a higher porosity than the first electrode part of the at least one densified electrode. In some designs, the densified electrode may be fabricated by densifying electrode layers via a pressure roller while maintaining a contacting part of the pressure roller at a temperature that is less than a temperature of the second electrode part. In some designs, the applied pressure is a time-varying (e.g., frequency modulated) pressure. In some designs, a drying time for a slurry to produce the densified electrode may range from around 1-120 seconds.

First claim

The invention claimed is:

1. A Li-ion battery cell, comprising:
anode and cathode electrodes;
an electrolyte ionically coupling the anode and the cathode electrodes; and
a separator electrically separating the anode and the cathode electrodes,
wherein the anode and cathode electrodes comprise at least one densified electrode exhibiting an areal capacity loading of more than about 4 mAh/cm 2 and comprising a first electrode part arranged on a current collector and a second electrode part on top of the first electrode part, the second electrode part of the at least one densified electrode having a higher porosity than the first electrode part of the at least one densified electrode.

2. The Li-ion battery cell of claim 1 , wherein the anode electrode comprises silicon (Si), carbon (C), or a combination of Si and C.

3. The Li-ion battery cell of claim 2 , wherein Si in the anode electrode ranges from around 5 wt. % to around 80 wt. %.

4. The Li-ion battery cell of claim 2 , wherein the anode electrode comprises Si-containing composite particles.

5. The Li-ion battery cell of claim 1 , wherein a total energy that may be stored in the Li-ion battery cell exceeds about 10 Wh.

6. The Li-ion battery cell of claim 1 , wherein a volumetric energy density of the Li-ion battery cell exceeds about 600 Wh/L.

7. The Li-ion battery cell of claim 6 , wherein the volumetric energy density of the Li-ion battery cell exceeds about 800 Wh/L.

8. The Li-ion battery cell of claim 1 , wherein a volumetric power density of the Li-ion battery cell exceeds about 1600 Wh/L when measured at around 40° C.

9. The Li-ion battery cell of claim 1 , wherein the Li-ion battery cell is configured to discharge about 80% or more of its maximum stored energy within about 20 minutes or less when discharged at around 40° C.

10. The Li-ion battery cell of claim 1 , wherein the Li-ion battery cell is configured charge from around 10% state of charge to around 80% state of charge within about 20 minutes or less when charged at around 40° C.

11. A densified electrode for a Li-ion battery, comprising:
a first electrode part arranged on a current collector; and
a second electrode part arranged on top of the first electrode part, the second electrode part having a higher porosity than the first electrode part,
wherein the densified electrode exhibits an areal capacity loading in excess of about 4 mAh/cm 2 .

12. The densified electrode of claim 11 , wherein an average thickness of the densified electrode ranges from around 60 micron to around 800 micron.

13. The densified electrode of claim 11 , wherein an average porosity of the densified electrode is below around 20 vol. %.

14. A method of fabricating the at least one densified electrode of the Li-ion battery cell of claim 1 , comprising:
coating the current collector with a set of electrode layers so as to define the first electrode part arranged on the current collector and the second electrode part arranged on top of the first electrode part; and
densifying the set of electrode layers after the coating via a pressure roller to produce a densified anode electrode or a densified cathode electrode of the at least one densified electrode while maintaining a contacting part of the pressure roller at a temperature that is less than a temperature of the second electrode part.

15. The method of claim 14 , wherein the temperature of the current collector exceeds the temperature of the contacting part of the pressure roller by around 20° C. or more.

16. A method of fabricating the at least one densified electrode of the Li-ion battery cell of claim 1 , comprising:
coating the current collector with one or more electrode layers; and
densifying the one or more electrode layers after the coating via applying a time-varying pressure to produce a densified anode electrode or a densified cathode electrode of the at least one densified electrode.

17. The method of claim 16 , wherein an average amplitude of the time-varying pressure during the densifying ranges from around 1% to around 50% of the maximum pressure.

18. The method of claim 16 , wherein the time-varying pressure is modulated in accordance with a defined frequency or range of frequencies.

19. The method of claim 18 , wherein the frequency of the time-varying pressure modulation ranges from around 0.1 Hz to around 10 MHz.

20. The method of claim 16 , wherein the densifying comprises roll-to-roll continuous electrode densification.

21. A method of fabricating the at least one densified electrode of the Li-ion battery cell of claim 1 , comprising:
coating the current collector with an electrode slurry comprising at least active electrode particles and a solvent;
drying, during a drying time, the electrode slurry to produce an at least partially dried electrode coating,
wherein the drying time ranges from around 1 to around 120 seconds; and
applying a pressure to the electrode slurry to produce a densified anode electrode or a densified cathode electrode of the at least one densified electrode.

22. The method of claim 21 , wherein the drying comprises:
heating the electrode slurry through the current collector, another hot object, or a combination thereof.

23. The method of claim 22 , wherein an average temperature of the current collector and/or the hot object during the drying exceeds about 200° C.

24. The method of claim 21 , wherein the coating and drying is performed continuously.

Assignees

• Sila Nanotechnologies Inc

Inventors

• Yushin Gleb
• Berdichevsky Gene

Classifications

• H01M4/625

  Carbon or graphite · CPC title

• H01M2004/021

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

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M10/0525

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