Methods of making battery electrodes with tubes, optimized solvent to powder weight ratios, and specified calendar roller diameters

Patent metadata

Field	Value
Publication number	US-11735706-B2
Application number	US-202017101648-A
Country	US
Kind code	B2
Filing date	Nov 23, 2020
Priority date	Sep 16, 2016
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

A method includes mixing a solvent with a dry cathode mixture to form a slurry. The dry cathode mixture includes a cathode active material, a conductive diluent, and a polymeric binder. The method further includes removing the solvent from the slurry to form a composition and calendering, in a first calendering step, the composition to form a sheet. The calendering the composition includes passing the composition between calender rollers.

First claim

The invention claimed is:

1. A method, comprising:
mixing a solvent with a dry cathode mixture to form a slurry, the dry cathode mixture including a cathode active material, a conductive diluent, and a polymeric binder;
removing at least some of the solvent from the slurry to form a composition;
feeding the composition into a bag or a tube;
calendering, in a first calendering step, the composition in the bag or the tube to form a sheet, calendering the composition including passing the composition in the bag or the tube between calender rollers.

2. The method according to claim 1 , further comprising:
baking the sheet at a temperature of 25° C. to 150° C. for at least 15 minutes to form a dry sheet; and
cutting the dry sheet into coupons.

3. The method according to claim 2 , further comprising:
calendering, in a second calendering step, the coupons to form pressed coupons.

4. The method according to claim 3 , further comprising baking the pressed coupons to form cathodes by subjecting the pressed coupons to a temperature of 25° C. to 150° C. for at least one hour.

5. The method of claim 3 , wherein baking the pressed coupons includes subjecting the pressed coupons to a temperature of 60° C. to 150° C. for 3-12 hours.

6. The method of claim 3 , wherein baking the pressed coupons includes subjecting the pressed coupons to a temperature of 80° C. to 150° C. for 3-9 hours.

7. The method of claim 2 , wherein the baking the sheet includes subjecting the sheet to a temperature of 25° C. to 150° C. for 15 minutes to 3 hours+15 minutes.

8. The method of claim 2 , wherein baking the sheet includes subjecting the sheet to a temperature of 80° C. to 150° C. for 1 hour to 2 hours.

9. The method of claim 2 , wherein:
baking the sheet includes subjecting the sheet to a temperature of 60° C. to 150° C. for 15 minutes to 3 hours.

10. The method of claim 1 , wherein:
the cathode active material comprises silver vanadium oxide;
the conductive diluent comprises graphite and carbon black; and
the polymeric binder comprises polytetrafluoroethylene.

11. The method of claim 1 , wherein, during mixing of the solvent with the dry cathode mixture to form a slurry, the amount of solvent mixed with the dry cathode mixture is 55 to 75 wt % of the total weight of the slurry.

12. The method of claim 1 , wherein the slurry has a first solvent to powder weight ratio, and
wherein the removing at least some of the solvent from the slurry is performed such that after the solvent removal, solvent to powder weight ratio is reduced to 15% to 25% of the first solvent to powder weight ratio.

13. The method of claim 1 , wherein calendering the composition to form a sheet comprises feeding the composition into a plastic tube and calendering the plastic tube using a calender machine that includes calender rollers with a diameter of 1.5 inches.

14. The method of claim 1 , wherein:
the solvent includes a liquid paraffin;
mixing the solvent with the dry cathode mixture includes adding the solvent to the dry cathode mixture to form an electrode active mixture having a 1.2 liquid to 1.0 solid weight ratio;
mixing the electrode active mixture to disperse the binder;
removing the solvent from the slurry to form the composition comprises reducing the solvent to powder weight ratio to form a paste that is substantially 22% solvent by weight; and
calendering the composition to form the sheet comprises:
feeding the paste into a plastic tube; and then
calendering the plastic tube to form a calendered paste.

15. The method of claim 14 , wherein calendering the plastic tube comprises calendering the plastic tube using calender rollers that are between 1 inch and 3 inches in diameter.

16. The method of claim 14 , wherein calendering the composition to form the sheet further comprises:
calendering the plastic tube a plurality of times;
removing the plastic tube from the paste to form the sheet;
calendering the sheet;
cutting the calendered sheet into a first sheet and a second sheet; and
stacking the first sheet and the second sheet to form a stacked sheet.

17. The method of claim 16 , wherein calendering the composition to form the sheet further comprises calendering the stacked sheet in a direction that is different from a direction in which the sheet was calendered.

18. The method of claim 14 , wherein calendering the composition to form the sheet further comprises:
removing the calendered paste from the plastic tube; and
calendering the calendered paste to form the sheet with a thickness of 0.04 to 0.012 inches.

19. A method comprising:
mixing a solvent with a dry cathode mixture to form a slurry, the dry cathode mixture including a cathode active material, a conductive diluent, and a polymeric binder;
removing at least some of the solvent from the slurry to form a composition; and
calendering, in a first calendering step, the composition to form a sheet, calendering the composition including passing the composition between calender rollers,
wherein the slurry has a solvent to powder weight ratio which is a 1.2 liquid to 1.0 solid weight ratio, the solvent being a liquid paraffin.

20. A method comprising:
mixing a solvent with a dry cathode mixture to form a slurry, the dry cathode mixture including a cathode active material, a conductive diluent, and a polymeric binder;
removing at least some of the solvent from the slurry to form a composition; and
calendering, in a first calendering step, the composition to form a sheet, calendering the composition including passing the composition between calender rollers,
wherein calendering the composition to form the sheet comprises feeding the composition into a plastic tube and calendering the plastic tube using a calender machine comprising the calender rollers, the diameter of the calender rollers is 4 inches or smaller, and calendering the plastic tube includes passing the plastic tube between the calender rollers.

Assignees

• Pacesetter Inc

Inventors

• Jiang Xiaofei
• Bruch Russell
• Beauvais Joseph

Classifications

• H01M4/0435 Primary

  Rolling or calendering · CPC title

• B29B7/002

  Methods (chemical aspects C08J3/00) · CPC title

• B29C43/24

  Calendering · CPC title

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M4/08

  Processes of manufacture · CPC title