Auxiliary current collector of capacitor

Abstract

The invention provides a battery, a capacitor auxiliary current collector and a method for a vehicle battery pack. The vehicle battery pack includes a pack housing and at least one vehicle battery cell carried by the pack housing. The at least one vehicle battery cell includes a cathode, an anode, a separator, and an electrolyte. The at least one vehicle battery cell also includes a current collector and a multifunctional coating disposed on and adhered to at least one side of the current collector. The multi-functional coating is configured to provide a quick charge capability for a vehicle battery pack. The multifunctional coating includes a capacitor material configured to enhance pulse and continuous charge rate capability, a conductive filler configured to provide electrical conductivity, and a binder configured to provide adhesion capability between the multifunctional coating and the current collector.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to vehicles and, more particularly, to a current collector in a vehicle battery system. BACKGROUND

[0002] Electric vehicles use multi-cell batteries to provide electrical power to provide the power to drive the vehicle and to provide electrical power to many devices on the vehicle. Batteries composed of many lithium-ion electrochemical cells are an example of such power sources.

[0003] In certain applications, it can be useful to combine a lithium-ion battery with a capacitor. Such a capacitor can be charged during vehicle braking. The resulting stored charge can be used to recharge the cells of the lithium-ion battery. The capacitor can provide fast charge capability to the lithium-ion battery cells.

[0004] While the prior art methods and systems attempt to charge lithium-ion battery cells with a capacitor and can achieve their particular purpose, there remains a need for new and improved battery charging. SUMMARY

[0005] According to several aspects of the present disclosure, a vehicle battery pack with a capacitor-assisted current collector is provided. The vehicle battery pack includes a battery pack housing and at least one vehicle battery cell carried by the battery pack housing. The at least one vehicle battery cell includes a cathode, an anode, a separator, and an electrolyte. The at least one vehicle battery cell further includes a current collector and a multifunctional coating disposed on and adhered to at least one side of the current collector. The multifunctional coating is configured to provide fast charge capability to the vehicle battery pack. The multifunctional coating includes a capacitor material configured to enhance pulse and continuous charge rate capability, a conductive filler configured to provide electrical conductivity, and a binder configured to provide adhesion capability between the multifunctional coating and the current collector.

[0006] According to another aspect of the present disclosure, a vehicle battery pack with a capacitor-assisted current collector includes a current collector having an aluminum foil with a thickness of about 10 microns.

[0007] According to another aspect of the present disclosure, a vehicle battery pack with a capacitor-assisted current collector includes a capacitor material disposed on and adhered to the current collector in a wave configuration and rivet interface, which provides adhesion.

[0008] According to another aspect of the present disclosure, a vehicle battery pack with a capacitor-assisted current collector includes a capacitor material in a gravure configuration on the current collector.

[0009] According to another aspect of the present disclosure, a vehicle battery pack with a capacitor-assisted current collector includes a multifunctional coating with a thickness between about 4 microns and about 30 microns.

[0010] According to another aspect of the present disclosure, a vehicle battery pack with a capacitor-assisted current collector includes a spherical capacitor material having a diameter of about one micron.

[0011] According to another aspect of the present disclosure, a vehicle battery pack with a capacitor-assisted current collector includes a multifunctional coating having a flat surface with a thickness between about 0.5 microns and 20 microns.

[0012] According to another aspect of the present disclosure, a vehicle battery pack with a capacitor-assisted current collector includes a multifunctional coating having a carbon layer disposed on the current collector and a capacitor layer disposed on the carbon layer.

[0013] According to another aspect of the present disclosure, a vehicle battery pack with a capacitor-assisted current collector includes a multifunctional coating that is about 40-80 weight percent activated carbon, about 18-40 weight percent conductive carbon, and about 2-20 weight percent binder.

[0014] According to another aspect of the present disclosure, a vehicle battery pack with a capacitor-assisted current collector includes a multifunctional coating having a dispersant including at least one of polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP), and the dispersant comprises about 0.1-5 weight percent of the multifunctional coating.

[0015] According to another aspect of the present disclosure, a vehicle battery pack with a capacitor-assisted current collector includes a multifunctional coating having a mass loading between about 0.01-1 milligrams per square centimeter.

[0016] According to another aspect of the present disclosure, a vehicle battery pack with a capacitor-assisted current collector includes a capacitor material including at least one of carbon, a metal oxide, or a polymer.

[0017] According to another aspect of the present disclosure, a vehicle battery pack with a capacitor-assisted current collector includes a conductive filler including at least one of carbon black, graphite, graphene, graphene oxide, conductive carbon black (Super P), acetylene black, Ketjen black, single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), or an oxide including at least one of a simple oxide, a superconducting oxide, a carbide, or a silicide.

[0018] According to another aspect of the present disclosure, a vehicle battery pack with a capacitor-assisted current collector includes a binder including at least one of polyacrylic acid (PAA), carboxymethylcellulose (CMC) / styrene butadiene rubber (SBR), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), or N-methyl-2-pyrrolidone (NMP).

[0019] According to another aspect of the disclosure, a vehicle battery pack with a capacitor assisted current collector includes a current collector formed from at least one of a solid metal foil, a mesh foil, or a three-dimensional foam composite.

[0020] According to another aspect of the disclosure, a vehicle battery pack with a capacitor assisted current collector includes a current collector formed from at least one of aluminum or copper.

[0021] According to several aspects of the disclosure, a capacitor assisted current collector is provided. The capacitor assisted current collector includes a current collector and a multifunctional coating adhered to at least one side of the current collector. The multifunctional coating is configured to provide fast charging capability for a vehicle battery pack. The multifunctional coating includes a capacitor material configured to enhance pulse and continuous charge rate capability, a conductive filler configured to provide electrical conductivity, and a binder configured to provide adhesion capability between the multifunctional coating and the current collector.

[0022] According to several aspects of the disclosure, a method for forming a capacitor assisted current collector is provided. The method includes mixing a first slurry using a solvent and gravure printing the first slurry on an aluminum current collector. The first slurry includes conductive carbon. The method further includes drying the first slurry using a heater to form a dried first slurry layer and a multifunctional coating. The multifunctional coating has a solids content of about 20 wt.%, and the multifunctional coating is configured to provide fast charging capability for a vehicle battery pack.

[0023] According to another aspect of the disclosure, the method includes a first slurry including conductive carbon, a conductive filler, and a binder.

[0024] According to another aspect of the disclosure, the method further includes mixing a second slurry including activated carbon, coating the dried first slurry layer with the second slurry, and drying the second slurry to form a capacitor layer.

[0025] Other applications of the disclosure will become apparent from the detailed description provided below. It should be understood that the detailed description and specific examples, while indicating certain embodiments of the disclosure, are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.

[0026] The above features and advantages of the presently disclosed systems and methods, and other features and advantages of the presently disclosed systems and methods, will become apparent from the detailed description, which follows, taken in conjunction with the accompanying drawings, including the claims and examples. BRIEF DESCRIPTION OF DRAWINGS

[0027] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0028] Figure 1 is a perspective view illustrating an example of a vehicle with a battery pack including a battery cell with a capacitor assisted current collector, in accordance with the present disclosure.

[0029] Figure 2 is a perspective view of a vehicle battery pack according to the present disclosure. Figure 1 is a cross-sectional view of a capacitor-assisted current collector in a vehicle battery pack according to the present disclosure, wherein the capacitor-assisted current collector has a gravure-printed multifunctional coating.

[0030] Figure 3 is a perspective view of a vehicle battery pack according to the present disclosure. Figure 1 is a cross-sectional view of a capacitor-assisted current collector in a vehicle battery pack according to the present disclosure, wherein the capacitor-assisted current collector has a spherical capacitor material embedded within a multifunctional coating.

[0031] Figure 4 is a perspective view of a vehicle battery pack according to the present disclosure. Figure 1 is a cross-sectional view of a capacitor-assisted current collector in a vehicle battery pack according to the present disclosure, wherein the capacitor-assisted current collector has a multifunctional coating including a carbon layer and a capacitor layer disposed on the carbon layer.

[0032] Figure 5 is a flowchart of a method for forming a capacitor-assisted current collector according to the present disclosure. Figures 2 to 4 is a perspective view of a vehicle battery pack according to the present disclosure. DETAILED DESCRIPTION

[0033] Reference will now be made in detail to several examples of the present disclosure shown in the accompanying drawings. Wherever possible, the same or like reference numbers will be used throughout the drawings and the description to refer to the same or like parts or steps. The following description is merely exemplary in nature and is not intended to limit the present disclosure, application or uses.

[0034] Disclosed herein is a vehicle battery pack including a capacitor-assisted current collector. The capacitor-assisted current collector has a multifunctional coating with ultra-fast charging capability and a special design suitable for use in high-power batteries.

[0035] Referring to Figure 1 , a perspective view of a vehicle 10 having a battery pack 12 according to the present disclosure is shown. The battery pack 12 is shown with an exemplary vehicle 10. The vehicle 10 is an electric or hybrid vehicle having wheels 14 driven by at least one electric motor / inverter 16. The electric motor / inverter 16 receives power from the battery pack 12. While the vehicle 10 is shown as a passenger road vehicle, it should be understood that the battery pack 12 can be used with various other types of vehicles. For example, the battery pack 12 can be used in a marine vehicle, such as a boat, or an aerial vehicle, such as a drone or passenger aircraft. Further, the battery pack 12 can be used as a stationary power source separate and independent from a vehicle. The battery pack 12 includes a housing 18 for carrying and supporting a plurality of battery cells 20. In an example, the battery pack 12 can have fifty or more battery cells 20. Each battery cell 20 includes a cathode electrode (not shown), an anode electrode (not shown), a separator (not shown), and an electrolyte (not shown).

[0036] Figure 2 A capacitor-assisted current collector 22 having a multifunctional coating 24 is shown, where the current collector 22 includes within each cell 20 as part of the cathode and / or anode electrode. The current collector 22 functions as a bridging function, supports active materials such as active cathode and anode materials, binders, and conductive additives, and electrochemically connects the overall structure of the cathode and anode to the external circuit. The current collector 22 can be formed of aluminum, stainless steel, copper, three-dimensional (3D) foam composites, composite types, or other suitable conductive materials. Further, the current collector 22 can be in the form of a solid metal foil, a meshed foil, and / or a three-dimensional (3D) composite or composite-type current collector. Some examples of 3D composite or composite-type current collectors 22 can include carbon fibers and carbon nanotubes (CNTs), polymer-carbon composites, conductive resins, and carbon-coated aluminum foils, among others. One example of a composite-type current collector 22 includes a battery current collector material having a three-layer structure made of a metal, a polymer, and a metal (e.g., aluminum, polyethylene terephthalate (PET), aluminum). The layers can be formed by metallization with a thin layer of metal or magnetron sputtering a biaxially oriented film substrate (e.g., polyethylene terephthalate (PET) or polypropylene (PP)). The middle layer can also be made of polyimide (PI) or other suitable polymer or non-metallic material. Additionally, the current collector 22 can have a variety of thicknesses (e.g., 4-30 micrometers (pm)) depending on its application. For example, the thickness h CC of a copper current collector 22 for an anode can be between about 4-12 pm. In another example, the thickness h CC of an aluminum current collector 22 for a cathode can be between about 10-20 pm. In Figure 2 the particular example shown, the current collector 22 is a solid metal foil formed of aluminum having a thickness h CC of about 10 pm. In this case, the meaning of the term“about” will be understood by one skilled in the art. Alternatively, the term“about” means ±0.5 pm.

[0037] The multifunctional coating 24 is disposed on and adhered to at least one side of the current collector 22. In Figure 2 the particular example shown, the multifunctional coating 24 is shown on both sides of the current collector 22, although in some cases, the multifunctional coating 24 can be disposed on only one side of the current collector 22. The multifunctional coating 24 is configured to provide fast charging capability for the vehicle battery pack 12. The multifunctional coating 24 can include a dispersant such as polyvinyl alcohol (PVA) and / or polyvinylpyrrolidone (PVP). When included, the dispersant can comprise about 0.1-5 weight percent (wt. %) of the overall multifunctional coating 24.

[0038] The multifunctional coating 24 has a mass loading between about 0.01-1 milligrams per square centimeter (mg / cm 2 ). Preferably, the multifunctional coating 24 has a mass loading between about 0.03-0.2 mg / cm 2 . In this case, one skilled in the art will understand the meaning of the term“about”. Alternatively, the term“about” means ±0.01 mg / cm 2 . Further, the multifunctional coating 24 has a thickness h CL between about 0.1-30 pm. Preferably, the multifunctional coating 24 has a thickness h CL between about 1-10 pm.

[0039] The multifunctional coating 24 includes a capacitor layer 26, a conductive filler 28, and a binder 30. In one example, the multifunctional coating 24 is about 40-80 weight percent capacitor layer 26, about 18-40 weight percent conductive carbon, and about 2-20 weight percent binder. In this case, one skilled in the art will understand the meaning of the term“about”. Alternatively, the term“about” means ±1 wt. %.

[0040] The capacitor layer 26 is configured to enhance the pulse and continuous charge rate capability of each battery cell 20 and the entire vehicle battery pack 12. The capacitor layer 26 can include carbon-based materials, such as activated carbon, graphene, carbon nanotubes, and the like. Preferably, the capacitor layer 26 includes activated carbon having a particle size distribution D50 between 0.5-20 pm. The term D50 refers to the median particle size in the distribution, meaning that 50% of the particles are smaller than this size and 50% of the particles are larger than this size. More preferably, the capacitor layer 26 includes activated carbon having a particle size distribution D50 of 1-8 pm. The capacitor layer 26 can also include metal oxides, such as MO x , where M can be cobalt (Co), ruthenium (Ru), and / or niobium (Nb), among others. The capacitor layer 26 can also include polymers, such as polyaniline, polyacetylene, and the like, or combinations thereof.

[0041] The conductive filler 28 is configured to provide electrical conductivity to the capacitor-assisted current collector 22 and the vehicle battery pack 12. The conductive filler 28 can include carbon-based materials, such as carbon black, graphite, graphene, graphene oxide, conductive carbon black (Super P), acetylene black, ketjen black, single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), other electronically conductive additives, or combinations thereof. The conductive filler 28 can also include oxides, such as simple oxides (e.g., ruthenium (IV) oxide (Ru02), tin (IV) oxide (Sn02), zinc oxide (ZnO), germanium (III) oxide (Ge203), and superconducting oxides (e.g., yttrium barium copper oxide (YBa2Cu307), lanthanum calcium manganate (La 0.75 Ca 0.25MnO3), carbides (e.g., silicon discarbide (SiC2), silicides (e.g., molybdenum disilicide (MoSi2), or combinations thereof).

[0042] Adhesive 30 is configured to provide adhesion between the multifunctional coating 24 and the current collector 22. Adhesive 30 may include aqueous adhesives such as polyacrylic acid (PAA), carboxymethyl cellulose (CMC) / styrene-butadiene rubber (SBR), polyacrylonitrile (PAN), and combinations thereof. Adhesive 30 may also include non-aqueous adhesives such as polyvinylidene fluoride (PVDF), N-methyl-2-pyrrolidone (NMP), and combinations thereof.

[0043] Still referencing Figure 2 The multifunctional coating 24 has a wavy structure and a riveted interface. In this configuration, the capacitor layer 26 can be gravure-printed onto the current collector 22. Gravure printing includes processes that cut, engrave, and / or etch an image or design onto a surface. For example, the capacitor layer 26 can be formed by depositing an activated carbon layer onto the current collector 22 and then performing gravure printing, including engraving or etching the surface of the activated carbon layer, to form a series of peaks 32 and valleys 34 on the capacitor layer 26. The resulting shape gives the capacitor layer 26 a gravure-printed configuration and a riveted interface, which improves the adhesion between the multifunctional coating 24 (e.g., the “active layer”) and the current collector 22. It should be understood that although the valleys 34 and peaks 32 are shown in a cross-sectional view, the valleys 34 and peaks 32 can be arranged in an ordered manner (e.g., rows) or can be arranged randomly within the capacitor layer 26. The multifunctional coating 24 also includes conductive fillers 28 and binders 30 disposed in the valleys 34 of the capacitor layer 26. Due to the height of peak 32, the thickness of the multifunctional coating 24 can be between about 4 and 30 μm, preferably between about 5 and 10 μm. In this document, the term "about" will be understood by those skilled in the art. Alternatively, the term "about" may mean ±0.1 μm. When using... Figure 3 In the configuration shown, and in one specific example, the load of the capacitor-assisted current collector 22 is 0.069 mg / cm². 2 The resistance is 0.37 ohm-cm, while the resistance of a traditional carbon-coated aluminum current collector is 3.654 ohm-cm, almost 10 times higher.

[0044] Figure 3Another example of a multifunctional coating 24 is shown, where the capacitor layer 26 has spherical capacitor particles 36. In this example, the spherical capacitor particles 36 are embedded within the conductive filler 28 and the binder 30. The conductive filler 28 and the binder 30 fill in around the spherical capacitor layer 26 and the spherical capacitor particles 36. Thus, the multifunctional coating 24 has a generally smooth and flat surface 38. The spherical capacitor particles 36 can have a variety of sizes (e.g., 0.75-3 pm). In one example, the spherical capacitor particles 36 have a D50 median particle size distribution of about one micrometer (pm). In this context, the term “about” is known to those skilled in the art. Alternatively, the term “about” means ±0.05 pm. The multifunctional coating 24 can have a variety of thicknesses h P (e.g., 1-3 pm). In one example, the thickness h P of the multifunctional coating 24 is about 1.25 pm. In this context, the term “about” is known to those skilled in the art. Alternatively, the term “about” means ±0.05 pm.

[0045] Figure 4 A multifunctional coating 24 having a plurality of material layers disposed on the current collector 22 is shown. The plurality of material layers includes a carbon layer 40 (e.g., Ketjen black) disposed directly on the current collector 22 (e.g., aluminum foil) and a capacitor layer 26 (e.g., activated carbon) disposed on the carbon layer 40. This example of the multifunctional coating 24 is formed in a two-step process using gravure printing as described below.

[0046] Referring to Figure 5 , a method 100 for forming a capacitor-assisted current collector according to the present disclosure is shown. The method begins at block 102. Block 102 describes mixing a first slurry using a solvent. The first slurry includes at least conductive carbon. In a specific example, the first slurry includes conductive carbon, conductive filler, and a binder. In this specific example, the slurry can include Ketjen black, a binder including polyacrylic acid (PAA), styrene butadiene rubber (SBR), and carboxymethyl cellulose (CMC), and activated carbon in a mass ratio of 30 / 20 / 50. The slurry can have a solid content of about 20%, but the slurry can also have other solid content percentages (e.g., 15%, 18%, 22%, 25%, etc.). In this context, the term “about” is known to those skilled in the art. Alternatively, the term “about” means ±1%. One example of a suitable solvent includes an N-methyl-2-pyrrolidone (NMP) solvent. The method 100 then moves to block 104.

[0047] Box 104 describes the gravure printing of a first paste onto a current collector 22. The current collector 22 can be copper and / or aluminum. The current collector 22 can be prepared using process steps such as alkaline etching or applying a carbon coating. Using a gravure printing process, the first paste is printed and / or a design is cut, engraved, and / or etched onto the first paste. For example, the first paste is printed onto the current collector 22 in a pattern using a gravure printing press, or printed and subsequently etched to have multiple peaks 32 and valleys 34. Using gravure printing allows for precise control over the thickness and pattern of the first paste.

[0048] Box 106 depicts the drying of a first slurry. Drying the first slurry may include using a heater. Using a heater may include heating the first slurry to a specific temperature to evaporate the solvent and cure the carbon slurry. For example, the first slurry may be dried in an oven or using a hot press. In some cases, drying the first slurry may include using a solvent recovery system (e.g., an N-methyl-2-pyrrolidone (NMP) solvent recovery system). Other examples of drying the first slurry may include using a UV curing process and / or a pressure curing process. Drying the first slurry results in a multifunctional coating 24 being applied to and adhered to the current collector 22.

[0049] Method 100 may also include frames 108, 110, and 112. Frame 108 depicts mixing a second slurry comprising activated carbon. In this case, the first slurry comprises carbon, such as Ketjen Black, which forms a carbon layer 40 upon drying, as... Figure 4 As shown in the example, the second slurry includes, for example, activated carbon, which forms a shape during drying as shown in the example. Figure 4 The capacitor layer 26 is shown. Mixing the second slurry may include using a solvent, such as N-methyl-2-pyrrolidone (NMP), to form the second slurry.

[0050] Box 110 describes coating a dried first slurry layer or carbon layer 40 with a second slurry. Coating the dried first slurry layer with a second slurry may include a process using, for example, a spraying process, an immersion process, a stencil process, or other suitable processes.

[0051] Box 112 depicts drying a second slurry to form a capacitor layer 26. Drying the second slurry may include using a heater. Using a heater may include heating the second slurry to a specific temperature to evaporate the solvent and cure the second slurry. For example, the second slurry may be dried in an oven or using a hot press. In some cases, drying the second slurry may include using a solvent recovery system (e.g., an N-methyl-2-pyrrolidone (NMP) solvent recovery system). Other examples of drying the second slurry may include using a UV curing process and / or a pressure curing process. Drying the second slurry results in the deposition of the capacitor layer 26 on a carbon layer 40, which in turn forms a multifunctional coating 24 disposed on and adhered to the current collector 22.

[0052] Compared to existing technology solutions, the capacitor-assisted current collector 22 disclosed herein is advantageous and beneficial. The capacitor-assisted current collector 22 provides ultra-fast charging capability in batteries (e.g., electric vehicle batteries) and is suitable for use in high-power batteries.

[0053] This description is merely 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, while this disclosure includes specific examples, its true scope should not be so limited, as other modifications will become apparent upon examination of the drawings, description, and appended claims.

Claims

1. A vehicle battery pack with a capacitor-assisted current collector, comprising: a battery pack housing; and at least one vehicle battery cell carried by the battery pack housing, wherein the at least one vehicle battery cell includes a cathode, an anode, a separator, and an electrolyte, and wherein the at least one vehicle battery cell further includes: a current collector; and a multifunctional coating disposed on and adhered to at least one side of the current collector, wherein the multifunctional coating is configured to provide fast charging capability for the vehicle battery pack, and wherein the multifunctional coating includes: a capacitor material configured to enhance pulse and continuous charge rate capability; an electrically conductive filler configured to provide electrical conductivity; and a binder configured to provide adhesive capability between the multifunctional coating and the current collector. The current collector includes aluminum foil having a thickness of about 10 microns.

2. The vehicle battery pack of claim 1, wherein, The capacitor material is disposed on and adhered to the current collector in a wave configuration and a rivet interface, wherein the rivet interface provides adhesion.

3. The vehicle battery pack of claim 1, wherein, The capacitor material is in a gravure configuration on the current collector.

4. The vehicle battery pack of claim 3, wherein, The multifunctional coating has a thickness between 4 microns and 30 microns.

5. The vehicle battery pack of claim 3, wherein, The capacitor material is spherical having a diameter of about one micron.

6. The vehicle battery pack of claim 1, wherein, The multifunctional coating has a flat surface having a thickness between 0.5 microns and 20 microns.

7. The vehicle battery pack of claim 6, wherein, The multifunctional coating includes a carbon layer disposed on the current collector and a capacitor layer disposed on the carbon layer.

8. The vehicle battery pack of claim 1, wherein, The multifunctional coating is 40-80 weight percent activated carbon, 18-40 weight percent electrically conductive carbon, and 2-20 weight percent binder.

9. The vehicle battery pack of claim 1, wherein, The multifunctional coating includes a dispersant including at least one of polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP), and wherein the dispersant comprises 0.1-5 weight percent of the multifunctional coating.

10. The vehicle battery pack of claim 1, wherein, ​

Images