Method for manufacturing an anode electrode for lithium-ion battery packs having an anode active material layer containing 2D carbon additives

Abstract

This invention relates to a method for manufacturing an anode electrode having an anode active material layer comprising a 2D carbon additive for use in lithium-ion battery packs. A method for manufacturing an anode electrode includes a) producing a slurry mixture comprising carboxymethyl cellulose (CMC) and water; b) after a) adding carbon black to the slurry mixture; c) after b) adding a two-dimensional (2D) carbon additive to the slurry mixture; d) after c) adding a silicon-based active material to the slurry mixture; e) after c) adding graphite to the slurry mixture; and f) after c) adding styrene-butadiene rubber (SBR) to the slurry mixture. Water is added to the slurry mixture after e) and before f). The CMC comprises 1% to 10% of the total CMC added to the slurry mixture. After e) and before f), 90% to 99% of the total CMC is added to the slurry mixture. The slurry mixture is used to manufacture the anode electrode.

Description

Technical Field

[0001] This disclosure relates to battery packs, and more particularly to a method for manufacturing an anode electrode for lithium-ion battery packs. Background Technology

[0002] The information provided in this section is intended to generally present the background of this disclosure. The work currently attributed to the inventors, to the extent described in this section, and aspects of the specification that may not have been otherwise identified as prior art at the time of application, are not expressly or impliedly acknowledged as prior art to this disclosure.

[0003] Electric vehicles (EVs), such as battery electric vehicles (BEVs), hybrid electric vehicles, and / or fuel cell vehicles, include one or more motors and battery pack systems, which include one or more battery cells, modules, and / or packs. A power control system is used to control the charging and / or discharging of the battery pack system during charging and / or driving.

[0004] The battery pack includes a cathode electrode, an anode electrode, and a separator. The cathode electrode includes a layer of cathode active material disposed on a cathode current collector. The anode electrode includes a layer of anode active material disposed on an anode current collector. Summary of the Invention

[0005] A method for manufacturing an anode electrode includes a) producing a slurry mixture comprising carboxymethyl cellulose (CMC) and water; b) after a) adding carbon black to the slurry mixture; c) after b) adding a two-dimensional (2D) carbon additive to the slurry mixture; d) after c) adding a silicon-based active material to the slurry mixture; e) after c) adding graphite to the slurry mixture; and f) after c) adding styrene-butadiene rubber (SBR) to the slurry mixture.

[0006] Among other characteristics, water is added to the slurry mixture after e) and before f). The CMC content is 1% to 10% of the total CMC added to the slurry mixture. After e) and before f), 90% to 99% of the total CMC is added to the slurry mixture.

[0007] Among other features, the method includes producing an anolyte active material layer using a slurry mixture. The method includes coating the slurry mixture onto an anode current collector to form an anolyte active material layer for the anode electrode. The method includes drying the slurry mixture in an oven. The method includes forming a battery pack comprising A anode electrodes, C cathode electrodes, and S separators, wherein A, C, and S are integers greater than zero.

[0008] Among other features, the anode active material layer comprises 80% to 98% by weight of graphite and silicon-based active material; 0.5% to 1.5% by weight of carbon black; 0.05% to 1.5% by weight of 2D carbon additive; 0.5% to 2.5% by weight of CMC; and 1.0% to 4.0% by weight of SBR.

[0009] Among other features, the 2D carbon additive is selected from carbon nanotubes (CNTs) and carbon nanofibers.

[0010] A method for manufacturing an anode electrode includes a) producing a slurry mixture comprising water, graphite, a silicon-based active material, a two-dimensional (2D) carbon additive, and carbon black; b) after a) adding carboxymethyl cellulose (CMC) to the slurry mixture; and c) after b) adding styrene-butadiene rubber (SBR) to the slurry mixture. Among other features, the method includes using the slurry mixture to produce an anode active material layer. The method includes coating the slurry mixture onto an anode current collector to form the anode active material layer of the anode electrode. The method includes drying the slurry mixture in an oven. The method includes forming a battery pack comprising A anode electrodes, C cathode electrodes, and S separators, wherein A, C, and S are integers greater than zero.

[0011] Among other features, the anode active material layer comprises 80% to 98% by weight of graphite and silicon-based active material; 0.5% to 1.5% by weight of carbon black; 0.05% to 1.5% by weight of 2D carbon additive; 0.5% to 2.5% by weight of CMC; and 1.0% to 4.0% by weight of SBR.

[0012] Among other features, the 2D carbon additive is selected from carbon nanotubes (CNTs) and carbon nanofibers.

[0013] A method for manufacturing an anode electrode includes a) producing a slurry mixture comprising water, graphite, carboxymethyl cellulose (CMC) and carbon black; b) after a) adding a silicon-based active material to the slurry mixture; c) after b) adding a two-dimensional (2D) carbon additive to the slurry mixture; and d) after c) adding styrene-butadiene rubber (SBR) to the slurry mixture.

[0014] Among other features, the method includes coating a slurry mixture onto an anode current collector to form an anode active material layer for the anode electrode. The anode active material layer comprises 80% to 98% by weight of graphite and silicon-based active material; 0.5% to 1.5% by weight of carbon black; 0.05% to 1.5% by weight of 2D carbon additives; 0.5% to 2.5% by weight of CMC; and 1.0% to 4.0% by weight of SBR.

[0015] The present invention discloses the following solutions: Option 1. A method for manufacturing an anode electrode, comprising: a) Produces a slurry mixture containing carboxymethyl cellulose (CMC) and water; b) After a), add carbon black to the slurry mixture; c) Following b), a two-dimensional (2D) carbon additive is added to the slurry mixture; d) Following c), a silicon-based active material is added to the slurry mixture; e) After c), add graphite to the slurry mixture; and f) After c), styrene-butadiene rubber (SBR) is added to the slurry mixture.

[0016] Option 2. The method according to Option 1, further comprising adding water to the slurry mixture after e) and before f).

[0017] Option 3. The method according to Option 1, wherein the CMC accounts for 1% to 10% of the total CMC added to the slurry mixture.

[0018] Option 4. The method according to Option 3, wherein 90% to 99% of the total CMC is added to the slurry mixture after e) and before f).

[0019] Option 5. The method according to Option 1, which includes using the slurry mixture to generate an anolyte active material layer.

[0020] Option 6. The method according to Option 1, which includes coating the slurry mixture onto an anode current collector to form an anode active material layer of an anode electrode.

[0021] Option 7. The method according to Option 3, which includes drying the slurry mixture in an oven.

[0022] Option 8. The method according to Option 6, further comprising forming a battery pack, the battery pack comprising: A anode electrode; C cathode electrodes; and S isolation components, Where A, C, and S are integers greater than zero.

[0023] Option 9. The method according to Option 6, wherein the anolyte active material layer comprises: 80% to 98% by weight of graphite and silicon-based active materials; 0.5% to 1.5% by weight of carbon black; 0.05% to 1.5% by weight of 2D carbon additives; 0.5% to 2.5% CMC by weight; and SBR from 1.0% to 4.0% by weight.

[0024] Option 10. The method according to Option 1, wherein the 2D carbon additive is selected from carbon nanotubes (CNTs) and carbon nanofibers.

[0025] Option 11. A method for manufacturing an anode electrode, comprising: a) Producing a slurry mixture containing water, graphite, silicon-based active materials, two-dimensional (2D) carbon additives, and carbon black; b) After a), add carboxymethyl cellulose (CMC) to the slurry mixture; c) Following b), styrene-butadiene rubber (SBR) is added to the slurry mixture.

[0026] Option 12. The method according to Option 11, which includes using the slurry mixture to generate an anolyte active material layer.

[0027] Option 13. The method according to Option 11, comprising coating the slurry mixture onto an anode current collector to form an anode active material layer of an anode electrode.

[0028] Option 14. The method according to Option 13, which includes drying the slurry mixture in an oven.

[0029] Option 15. The method according to Option 13, further comprising forming a battery pack, the battery pack comprising: A anode electrode; C cathode electrodes; and There are S isolation components, where A, C, and S are integers greater than zero.

[0030] Option 16. The method according to Option 13, wherein the anolyte active material layer comprises: 80% to 98% by weight of graphite and silicon-based active materials; 0.5% to 1.5% by weight of carbon black; 0.05% to 1.5% by weight of 2D carbon additives; 0.5% to 2.5% CMC by weight; and SBR from 1.0% to 4.0% by weight.

[0031] Option 17. The method according to Option 11, wherein the 2D carbon additive is selected from carbon nanotubes (CNTs) and carbon nanofibers.

[0032] Option 18. A method for manufacturing an anode electrode, comprising: a) Produces a slurry mixture containing water, graphite, carboxymethyl cellulose (CMC), and carbon black; b) Following a), a silicon-based active material is added to the slurry mixture; c) Following b), a two-dimensional (2D) carbon additive is added to the slurry mixture; and d) After c), styrene-butadiene rubber (SBR) is added to the slurry mixture.

[0033] Option 19. The method according to Option 18, further comprising coating the slurry mixture onto the anode current collector to form an anode active material layer of the anode electrode.

[0034] Option 20. The method according to Option 19, wherein the anolyte active material layer comprises: 80% to 98% by weight of graphite and silicon-based active materials; 0.5% to 1.5% by weight of carbon black; 0.05% to 1.5% by weight of 2D carbon additives; 0.5% to 2.5% CMC by weight; and SBR from 1.0% to 4.0% by weight.

[0035] Other applicable areas of this disclosure will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are intended for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0036] This disclosure will be more fully understood from the detailed embodiments and the accompanying drawings, in which: Figure 1 This is a side cross-section of a battery pack comprising A anode electrodes, C cathode electrodes, and S separators according to this disclosure; Figure 2 This is a flowchart of a method for preparing a slurry during the manufacture of A anode electrodes; Figure 3A This is a flowchart illustrating an example of a method for preparing a slurry during the manufacture of A anode electrodes according to this disclosure; Figure 3B This is a flowchart of a method for manufacturing an anode electrode and a battery pack according to the present disclosure; Figure 4 This is a flowchart of another example of a method for preparing a slurry during the manufacture of A anode electrodes according to the present disclosure; Figure 5This is a flowchart of another example of a method for preparing a slurry during the manufacture of A anode electrodes according to this disclosure; and Figure 6 This is a flowchart of another example of a method for preparing a slurry during the manufacture of A anode electrodes according to the present disclosure.

[0037] In the accompanying drawings, reference numerals may be used repeatedly to identify similar and / or identical elements. Detailed Implementation

[0038] Although this article describes the battery pack in the context of a vehicle, the battery pack can be used in other mobile or stationary applications.

[0039] The battery pack includes a cathode electrode, an anode electrode, and a separator. The cathode electrode includes a layer of cathode active material disposed on a cathode current collector. The anode electrode includes a layer of anode active material disposed on an anode current collector. During manufacturing, the cathode active material layer and / or the anode active material layer may include coatings (including one or more active materials, one or more conductive additives, and / or one or more binder materials) applied or cast onto the current collector.

[0040] The coating corresponding to the active material layer can be formed by mixing a slurry and applying the slurry to the current collector. For ease of manufacturing, the slurry should be easy to apply. In some instances, carboxymethyl cellulose (CMC) is dissolved in a solvent such as water and used as a thickener and binder in the manufacture of electrodes for lithium-ion battery packs. However, when 2D carbon additives (such as carbon nanotubes (CNTs) or carbon nanofibers) are used in the slurry, they may interact with CMC molecules, resulting in low flowability and / or gelation. Subsequent manufacturing using the slurry leads to coating inhomogeneity, delamination, and / or poor adhesion of the coating to the anode current collector.

[0041] This disclosure relates to a method for mixing a slurry comprising 2D carbon additives and CMC, the slurry being coated onto a substrate such as an anode current collector to form an anolyte active material layer of an anode electrode. The slurry described below is stable for more than two weeks, compared to previous slurries that underwent gelation within 12 hours.

[0042] To reduce the strong interaction between the 2D carbon additive and CMC, the CMC is dissolved in a solvent (such as water) before the 2D carbon additive is added. This mitigates the interaction between the CMC and the 2D carbon additive, improving the stability of the anode slurry. In some instances, the adhesion / peel strength of the anolyte layer on the anode current collector has increased by approximately 30% (e.g., from approximately 18 N / m to approximately 24 N / m), and no electrode layer delamination has been observed.

[0043] Now for reference Figure 1The battery pack 10 includes C cathode electrodes 20, A anode electrodes 40, and S spacers 32 arranged in a predetermined order within the battery pack stack 12, where C, S, and A are integers greater than zero. In some instances, the carrier 11 includes a battery pack module or package 13 containing the battery pack 10. The battery pack stack 12 is arranged within a housing 50 (e.g., a prismatic, cylindrical, or pouch-like housing).

[0044] C cathode electrodes 20-1, 20-2, ..., 20-C include a cathode active material layer 24 disposed on one or both sides of the cathode current collector 26. A anode electrodes 40-1, 40-2, ..., 40-A include an anode active material layer 42 disposed on one or both sides of the anode current collector 46. During charging / discharging, the A anode electrodes 40 and the C cathode electrodes 20 exchange lithium ions.

[0045] In some instances, the cathode active material layer 24 and / or the anode active material layer 44 include a coating comprising one or more active materials, one or more conductive additives, and / or one or more binder materials, which are cast or applied to the current collector.

[0046] In some instances, the anode current collector 46 and / or the cathode current collector 26 comprise metal foil, metal mesh, perforated metal, three-dimensional (3D) metal foam, and / or expanded metal. External tabs 28 and 48 are connected to the current collectors of the cathode and anode electrodes, respectively, and may be arranged on the same or different sides of the battery pack stack 12. External tabs 28 and 48 are connected to the terminals of the battery pack cells.

[0047] Now for reference Figure 2 This illustrates a method for mixing a slurry during the fabrication of A anode electrodes. At 110, a 2D carbon additive (such as carbon nanotubes (CNTs) or carbon nanofibers) and a solvent (such as water) are mixed. At 114, carboxymethyl cellulose (CMC) is added to the mixture. In some examples, the solids content at this point is approximately 1.5%. At 118, carbon black is added to the mixture. In some examples, the solids content at this point is approximately 1.9%. At 122, a silicon-based active material (such as silicon, engineered silicon, or silicon oxide) is added to the mixture. x (etc.). In some instances, the solid content at this point is approximately 7%.

[0048] At point 126, graphite powder is added to the mixture. In some examples, the solid content at this point is approximately 47%. At point 130, a solvent such as water is added to the mixture. In some examples, the solid content at this point is approximately 45%. At point 134, styrene-butadiene rubber (SBR) is added to the mixture.

[0049] After coating and drying, the anodic active material layer comprises 1.7 wt% CMC, 0.5 wt% carbon black, 0.1 wt% 2D carbon additives (such as single-walled CNTs (SWCNTs)), and 5.2 wt% silicon-based active material (such as SiO2). x ), 90% by weight graphite and 2.5% by weight SBR.

[0050] When 2D carbon additives (such as carbon nanotubes (CNTs) or carbon nanofibers) are used in slurries, interactions may occur between the 2D carbon additives and CMC molecules. After a relatively short period, these interactions lead to low flowability and / or gelation of the slurry (described in...). Figure 2 (In the middle). Subsequent manufacturing using slurry results in uneven coating, delamination, and / or poor adhesion of the coating to the anode current collector.

[0051] Now for reference Figure 3A The present disclosure illustrates a method for mixing a slurry during the manufacture of A anode electrodes. At 210, carboxymethyl cellulose (CMC) and a solvent (such as water) are mixed. At 214, carbon black is added to the mixture. In some examples, the solid content at this point is about 2%.

[0052] At point 218, a 2D carbon additive (e.g., CNTs and solvent) is added to the mixture. In some examples, the solid content at this point is approximately 1.6%. At point 222, a silicon-based active material is added to the mixture. In some examples, the solid content at this point is approximately 6%. At point 226, graphite powder is added to the mixture. In some examples, the solid content at this point is approximately 48%. At point 230, a solvent (e.g., water) is added to the mixture. In some examples, the solid content at this point is approximately 45%. At point 234, styrene-butadiene rubber (SBR) is added to the mixture.

[0053] Now for reference Figure 3B The slurry is coated onto the anode current collector to form the anode electrode at position 250. At position 252, the anode electrode is optionally dried in an oven. At position 254, the anode electrode is used to form the battery pack cell.

[0054] In some examples, the anode active material layer comprises 80 wt% to 98 wt% graphite and silicon-based active material, 0.5 wt% to 1.5 wt% carbon black, 0.05 wt% to 1.5 wt% 2D carbon additive, 0.5 wt% to 2.5 wt% CMC, and 1.0 wt% to 4.0 wt% SBR. In other examples, the anode active material layer comprises 1.0 wt% CMC, 0.7 wt% CB, 0.1 wt% single-walled CNTs (SWCNTs), and 5.2 wt% SiO2. x It contains 90% by weight graphite and 3% by weight SBR.

[0055] Now for reference Figure 4 This illustrates another method for mixing a slurry for the anode active material layer. At 310, a portion of the CMC solution (e.g., 1% to 10% of the total CMC) is mixed with a solvent such as water. At 314, carbon black is added. At 318, a two-dimensional (2D) carbon additive is added. At 322, a silicon-based active material is added. At 326, graphite powder is added. As will be understood, the order of steps 314 to 326 can be varied. At 330, the remaining portion of the CMC (90% to 99% of the total CMC) is added to the slurry mixture.

[0056] Now for reference Figure 5 This illustrates another method for mixing a slurry for the anode active material layer. At 410, a solvent (such as water), graphite, silicon-based active material, 2D carbon additive, and carbon black are mixed. At 414, CMC is added. At 418, SBR is added.

[0057] Now for reference Figure 6 This illustrates another method for mixing a slurry for the anolyte active material layer. At 510, a solvent (such as water), graphite, CMC, and carbon black are mixed. At 514, a silicon-based active material is added. At 518, a 2D carbon additive is added. At 522, SBR is added.

[0058] If it is understandable, Figures 4 to 6 The slurry mixing method also reduces the interaction between CMC and 2D carbon additives to improve the stability of the anode slurry and reduce delamination.

[0059] The slurry can be used in roll-to-roll processes for manufacturing anode electrodes and / or battery cells. In some instances, a doctor blade or grooving die is used to apply the slurry to the anode current collector. An oven can be used to heat the anode electrode to dry the slurry.

[0060] The foregoing description is illustrative in nature and is in no way intended to limit this disclosure, its application, or its use. The broad teachings of this disclosure can be implemented in many forms. Therefore, although this disclosure includes specific examples, its true scope should not be so limited, as other modifications will become apparent upon examination of the drawings, specification, and the following claims. It should be understood that one or more steps within the method may be performed in a different order (or simultaneously) without altering the principles of this disclosure. Furthermore, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of this disclosure may be implemented in any other embodiment and / or combined with features in any other embodiment, even if such combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations and combinations of one or more embodiments with each other remain within the scope of this disclosure.

Claims

1. A method for manufacturing an anode electrode, comprising: a) Produces a slurry mixture containing carboxymethyl cellulose (CMC) and water; b) After a), add carbon black to the slurry mixture; c) Following b), a two-dimensional (2D) carbon additive is added to the slurry mixture; d) Following c), a silicon-based active material is added to the slurry mixture; e) After c), add graphite to the slurry mixture; and f) After c), styrene-butadiene rubber (SBR) is added to the slurry mixture.

2. The method according to claim 1, further comprising adding water to the slurry mixture after e) and before f).

3. The method according to claim 1, wherein the CMC accounts for 1% to 10% of the total CMC added to the slurry mixture.

4. The method of claim 3, wherein 90% to 99% of the total CMC is added to the slurry mixture after e) and before f).

5. The method of claim 1, further comprising using the slurry mixture to generate an anolyte layer.

6. The method of claim 1, further comprising coating the slurry mixture onto an anode current collector to form an anode active material layer of an anode electrode.

7. The method of claim 3, further comprising drying the slurry mixture in an oven.

8. The method of claim 6, further comprising forming a battery pack, the battery pack comprising: A anode electrode; C cathode electrodes; and S isolation components, Where A, C, and S are integers greater than zero.

9. The method of claim 6, wherein the anolyte layer comprises: 80% to 98% by weight of graphite and silicon-based active materials; 0.5% to 1.5% by weight of carbon black; 0.05% to 1.5% by weight of 2D carbon additives; 0.5% to 2.5% CMC by weight; and SBR from 1.0% to 4.0% by weight.

10. The method according to claim 1, wherein the 2D carbon additive is selected from carbon nanotubes (CNTs) and carbon nanofibers.

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