Electrode assemblies including current limiters

Patent metadata

Field	Value
Publication number	US-12362439-B2
Application number	US-202318316321-A
Country	US
Kind code	B2
Filing date	May 12, 2023
Priority date	Mar 31, 2021
Publication date	Jul 15, 2025
Grant date	Jul 15, 2025

Abstract

A method includes stacking unit cells in a stacking direction. Each unit cell includes an electrode structure, a separator structure, and a counter-electrode structure. The electrode structure includes an electrode current collector and an electrode active material layer, and the counter-electrode structure includes a counter-electrode current collector and a counter-electrode active material layer. The electrode and counter-electrode structures extend in a longitudinal direction perpendicular to the stacking direction, and an end portion of the electrode current collector extends past the electrode active material and the separator structure in the longitudinal direction. The end portion of each electrode current collector is bent in a direction orthogonal to the longitudinal direction, an electrode busbar is positioned extending in the stacking direction with a surface adjacent the end portions, and heat and pressure are applied to the electrode busbar to adhere the end portions to the busbar through an adhesive layer.

First claim

What is claimed is:

1. An electrode assembly for cycling between a charged state and a discharged state within a range of normal operating temperatures between negative 30 degrees Celsius (° C.) and 80° C., the electrode assembly comprising:
a population of unit cells stacked atop each other in a stacking direction, each member of the unit cell population includes an electrode structure, a separator structure, and a counter-electrode structure, wherein:
the electrode structure comprises an electrode current collector and an electrode active material layer, the electrode structure extends in a longitudinal direction perpendicular to the stacking direction, an end portion of the electrode current collector extends past the electrode active material and the separator structure in the longitudinal direction, and the end portion of the electrode current collector comprises a bent portion that is bent in a direction orthogonal to the longitudinal direction of the electrode structure and extends in the stacking direction; and
the counter-electrode structure comprises a counter-electrode current collector and a counter-electrode active material layer, the counter-electrode structure extends in a longitudinal direction perpendicular to the stacking direction;

an electrode busbar extending in the stacking direction; and
a population of current limiters disposed between the bent end portion of the population of unit cells and the electrode busbar, wherein:
each member of the population of current limiters is disposed between the bent end portion of the electrode current collector of a different electrode structure and the electrode busbar to electrically connect the electrode structures to the electrode busbar;
the bent end portion of the electrode current collector has an inner surface and an outer surface opposite the inner surface, the inner surface being closer to the electrode active material layer than the outer surface;
the electrode busbar is positioned adjacent the outer surface of the bent end portion of the electrode current collector; and
one or more current limiters of the population of current limiters are disposed between the outer surface of the bent end portion of the electrode current collector and the electrode busbar.

2. The electrode assembly of claim 1 , wherein each member of the unit cell population has a cell resistance R1 and each member of the current limiter population has a resistance R2 such that R2/R1>0.01.

3. The electrode assembly of claim 1 , wherein the population of current limiters comprises a conductive adhesive.

4. The electrode assembly of claim 3 , wherein the conductive adhesive is comprised of a unitary conductive adhesive layer, and each member of the population of current limiters comprises a different portion of the unitary conductive adhesive layer.

5. The electrode assembly of claim 4 , wherein the unitary conductive adhesive layer is disposed on the electrode busbar.

6. The electrode assembly of claim 4 , wherein the conductive adhesive layer comprises an adhesive polymer and metal coated carbon fibers.

7. The electrode assembly of claim 6 , wherein the metal coated carbon fibers comprise nickel coated carbon fibers.

8. The electrode assembly of claim 7 , wherein the metal coated carbon fibers have a length and a diameter and an aspect ratio of the length to the diameter of the metal coated carbon fibers is between 10:1 and 10,000:1 inclusive.

9. The electrode assembly of claim 6 , wherein a melt flow index of the adhesive polymer determined according to ASTMD 1238 at 190° C. is between 0.1 to 1000 grams (g)/10 minutes (min).

10. The electrode assembly of claim 9 , wherein the melt flow index is between 0.1 to 100 g/10 min.

11. The electrode assembly of claim 9 , wherein the melt flow index is between 0.5 to 20 g/10 min.

12. The electrode assembly of claim 6 , wherein a melting point of the adhesive polymer is between 40° C. and 300° C.

13. The electrode assembly of claim 12 , wherein the melting point of the adhesive polymer is between 60° C. and 200° C.

14. The electrode assembly of claim 12 , wherein the melting point of the adhesive polymer is between 70° C. and 165° C.

15. The electrode assembly of claim 1 , wherein the electrode structure comprises a negative electrode structure, and the counter-electrode structure comprises a positive electrode structure.

16. The electrode assembly of claim 1 , wherein the electrode structure or the counter-electrode structure comprises an anodic electrode structure, the anodic electrode structure comprising graphite, silicon, or lithium metal.

17. The electrode assembly claim 1 , wherein the electrode structure or the counter-electrode structure comprises a cathodic electrode structure, the cathodic electrode structure comprising lithium iron phosphate (LFP) or lithium nickel manganese cobalt oxide (NMC).

18. The electrode assembly claim 1 , wherein the separator structure comprises a microporous separator material permeated with a liquid electrolyte.

19. The electrode assembly claim 1 , wherein the separator structure comprises a solid-state lithium ion conducting ceramics.

20. A method of assembling an electrode assembly for cycling between a charged state and a discharged state within a range of normal operating temperatures between negative 30 degrees Celsius (° C.) and 80° C., the method comprising:
stacking a population of unit cells atop each other in a stacking direction, each member of the unit cell population including an electrode structure, a separator structure, and a counter-electrode structure, wherein the electrode structure comprises an electrode current collector and an electrode active material layer, the counter-electrode structure comprises a counter-electrode current collector and a counter-electrode active material layer, the electrode structure and the counter-electrode structure extend in a longitudinal direction perpendicular to the stacking direction, and an end portion of the electrode current collector extends past the electrode active material and the separator structure in the longitudinal direction;
bending the end portion of the electrode current collector in a direction orthogonal to the longitudinal direction of the electrode structure and to extend in the stacking direction or opposite the stacking direction;
positioning an electrode busbar in the stacking direction such that a surface of the electrode busbar is located adjacent the bent end portion of the electrode current collector; and
electrically connecting the bent end portion of the electrode current collector to the electrode busbar though one or more current limiters of the population of current limiters wherein:
the bent end portion of the electrode current collector has an inner surface and an outer surface opposite the inner surface, the inner surface being closer to the electrode active material layer than the outer surface;
the electrode busbar is positioned adjacent the outer surface of the bent end portion of the electrode current collector; and
one or more current limiters of the population of current limiters are disposed between the outer surface of the bent end portion of the electrode current collector and the electrode busbar.

21. The method of claim 20 , wherein the population of current limiters comprises a conductive adhesive, the conductive adhesive is comprised of a unitary conductive adhesive layer, and each member of the population of current limiters comprises a different portion of the unitary

Assignees

• Enovix Corp

Inventors

• Armstrong Michael J
• Noelle Daniel J
• Busacca Robert S
• Valdes Bruno A
• Rosen Robert K
• Ramasubramanian Murali
• Lahiri Ashok
• Spotnitz Robert M

Classifications

• H01M50/531

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• H01M50/583

  in response to current, e.g. fuses · CPC title

• H01M50/572

  Means for preventing undesired use or discharge · CPC title

• H01M10/0585

  of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators · CPC title

• H01M10/0525

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