Densified battery electrodes and methods thereof

Patent metadata

Field	Value
Publication number	US-2020373555-A1
Application number	US-202016883661-A
Country	US
Kind code	A1
Filing date	May 26, 2020
Priority date	May 23, 2019
Publication date	Nov 26, 2020
Grant date	—

Abstract

In an aspect, a Li-ion cell may comprise a densified electrode exhibiting an areal capacity loading of more than about 4 mAh/cm2. 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

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 W/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 bottom 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 an electrode, comprising:
coating a current collector with a set of electrode layers so as to define a first electrode part arranged on the current collector and a 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 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 an electrode for a Li-ion battery, comprising:
coating a 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 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 an electrode for a Li-ion battery, comprising:
coating a current collector with an electrode slurry comprising at least active electrode particles and a solvent; and 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.

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 drying comprises:
applying a pressure to the electrode slurry.

25 . 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

• H01M4/0435 Primary

  Rolling or calendering · CPC title

• H01M4/0404

  by coating on electrode collectors · CPC title

• H01M4/1393

  of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title