Patent Application
20250149576
This application claims the benefit of Chinese Patent Application No. 202311484256.X, filed on Nov. 8, 2023. The entire disclosure of the application referenced above is incorporated herein by reference.
The information provided in this section is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
The present disclosure relates to battery cells, and more particularly to a battery cells including lithium metal anodes and LFP cathodes.
Electric vehicles (EVs) such as battery electric vehicles (BEVs), hybrid vehicles, and/or fuel cell vehicles include one or more electric machines and a battery system including one or more battery cells, modules, and/or packs. A power control system is used to control charging and/or discharging of the battery system during charging and/or driving.
A battery cell includes A anode electrodes including an anode active material layer comprising lithium metal active material and an anode current collector, C cathode electrodes including a cathode active material layer comprising LiFePO4 (LFP) active material and a cathode current collector, and S separators arranged between the A anode electrodes and the C cathode electrodes, where A, C, and S are integers greater than one. The S separators comprise a substrate including a coating layer.
In other features, the anode current collector comprises a wire mesh made of a material selected from a group consisting of copper and stainless steel. The anode current collector comprises foil made of a material selected from a group consisting of copper and stainless steel. The substrate of the S separators is selected from a polyolefin-based separator, a cellulose separator, a polyvinylidene fluoride (PVDF) membrane, and a porous polyimide membrane
In other features, the coating layer is selected from a group consisting of ceramic, polymer, alumina (Al2O3), Li1.3Al0.3Ti1.7(PO4)3 (LATP), polyvinylidene difluoride (PVDF), polymethyl methacrylate (PMMA), and combinations thereof, and the coating layer has a thickness in a range from 1 μm to 5 μm.
In other features, the wire mesh is in a range from 50 to 400 mesh. A thickness of the A anode electrodes is in a range from 70 to 120 μm and a width of the A anode electrodes is in a range from 50 mm to 500 mm. The S separators have a thickness in a range from 9 μm to 19 μm and a porosity in a range from 35 to 55%.
In other features, the cathode active material layer comprises the LFP active material, a carbon additive, and a binder. The LFP active material comprises 90 to 98 wt %, the carbon additive comprises 1 to 5 wt %, and the binder comprises 1 to 5 wt %.
In other features, the LFP active material further includes a carbon coating. The carbon coating is in a range from 0.5 wt % to 3 wt % and the LFP is in a range from 97 wt % to 99.5 wt % of the LFP active material. The binder comprises PTFE.
In other features, the carbon additive is selected from a group consisting of Super P, KS-6, graphite, graphene nanoplates, single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), and combinations thereof. Electrolyte comprises a lithium salt, a solvent, and an additive. The lithium salt is selected from a group including LiPF6 and LiFSI. The solvent is selected from a group consisting of carbonate ester or ether. The battery cell has an N/P ratio is in a range from 1.5 to 1.7.
A battery cell comprises A anode electrodes including an anode active material layer including lithium metal coating on an anode current collector. The anode current collector comprises a wire mesh made of a material selected from a group consisting of copper and stainless steel. C cathode electrodes include a cathode active material layer comprising a LiFePO4 (LFP) active material with a carbon coating and a cathode current collector. S separators are arranged between the A anode electrodes and the C cathode electrodes, where A, C, and S are integers greater than one. The S separators comprise a substrate including a coating layer. The substrate is selected from a group consisting of a polyolefin-based separator, a cellulose separator, a polyvinylidene fluoride (PVDF) membrane, and a porous polyimide membrane, and combinations thereof. The coating layer is selected from a group consisting of ceramic, polymer, alumina (Al2O3), Li1.3Al0.3Ti1.7(PO4)3(LATP), polyvinylidene difluoride (PVDF), polymethyl methacrylate (PMMA). An electrolyte comprises a lithium salt, a solvent, and an additive.
In other features, the cathode active material layer comprises the LFP active material, a carbon additive, and a binder. The LFP active material comprises 90 to 98 wt %, the carbon additive comprises 1 to 5 wt %, and the binder comprises 1 to 5 wt %. The S separators have a thickness in a range from 9 μm to 19 μm and a porosity in a range from 35 to 55%.
In other features, the carbon coating of the LFP active material is in a range from 0.5 wt % to 3 wt % and the LFP is in a range from 97 wt % to 99.5 wt %. The binder comprises PTFE. The carbon additive is selected from a group consisting of Super P, KS-6, graphite, graphene nanoplates, single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), and combinations thereof.
Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.
The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:
In the drawings, reference numbers may be reused to identify similar and/or identical elements.
While battery cells according to the present disclosure are shown in the context of electric vehicles, the battery cells can be used in stationary applications and/or other applications.
Lithium ion battery cells including NMC or NMCA cathodes and graphite anodes have a high energy density and good cycling performance. However, these battery cells do not have high thermal stability and therefore thermal runaway behavior is problematic.
Battery cells according to the present disclosure include a lithium metal anode and an LFP cathode. As will be described further below, the battery cells according to the present disclosure enable high thermal stability and outstanding cyclability without sacrificing energy density.
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In some examples, the cathode current collectors 26 and the anode current collectors 46 comprise a metal mesh, metal foil, or expanded metal. In some examples, the anode current collectors 46 are made of a material selected from a group consisting of copper and stainless steel. In some examples, the cathode current collectors are made of aluminum or other suitable current collector materials.
In some examples, the cathode active material layers 24 comprise coatings including one or more active materials, one or more conductive fillers/additives, and/or one or more binder materials that are applied to the cathode current collectors 26 in a roll-to-roll production line or other manufacturing method. External tabs 28 and 48 can be connected to the current collectors of the anode electrodes and cathode electrodes on the same or opposite sides of the battery stack 12.
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In some examples, the metal mesh of the anode current collector 46 is in a range from 50 to 400 mesh (e.g., openings per inch). In some examples, the anode electrodes 40 have a capacity loading in a range from 6 to 8 mAh/cm2 (e.g. 6.5 mAh/cm2) for a single-sided lithium coating having a thickness in a range from 30-40 μm. In some examples, the total thickness of the anode electrodes 40 is in a range from 70 μm to 120 μm. In some examples, the anode electrodes have a width in a range from 50 mm to 500 mm. In some examples, the anode electrodes have a width in a range from 50 mm to 200 mm.
In some examples, the substrate 220 is selected from a group consisting of a polyolefin-based separator (e.g., polyacetylene: polypropylene (PP), polyethylene (PE), dual-layer type: PP-PE, three-layer type: PP-PE-PP), a cellulose separator, a polyvinylidene fluoride (PVDF) membrane, and a porous polyimide membrane. In some examples, the coating layer 222 comprises ceramic or polymer. An example of ceramic includes alumina (Al2O3) or Li1.3Al0.3Ti1.7(PO4)3 (LATP), although other ceramics can be used. Examples of polymer include polyvinylidene difluoride (PVDF), polymethyl methacrylate (PMMA), or another suitable polymer. The coating layer is arranged on one or both sides of the substrate 220.
In some examples, the separator 32 has a thickness in a range from 9 μm to 19 μm. In some examples, the separator 32 has a porosity in a range from 35 to 55% (e.g., 40%). In some examples, the coating layer 222 has a thickness in a range from 1 μm to 5 μm. In some examples, the separator 32 has a thickness of 16 μm, a porosity of 40%, and the coating layer 222 includes alumina (Al2O3) having a thickness of 2 μm.
In some examples, the cathode active material layer comprises LFP active material, a carbon additive, and a binder. In some examples, the LFP active material comprises 90 to 98 wt %, the carbon additive comprises 1 to 5 wt %, and the binder comprises 1 to 5 wt %.
In some examples, the LFP active material has a surface area of 3 m2/g to 20 m2/g. In some examples, the LFP active material further includes a carbon coating. In some examples, the carbon coating on the LFP active material is in a range from 0.5 wt % to 3 wt % and the LFP is in a range from 97 wt % to 99.5 wt %. In some examples, the LFP active material has a D50 in a range from 0.5 μm to 15 μm. In some examples, the surface area of the LFP active material is 10.6 m2/g and the carbon coating comprises 1.2 wt % with a D50 of 1.2 μm.
In some examples, the binder comprises PTFE. In some examples, the carbon additive is selected from a group consisting of Super P, KS-6, graphite, graphene nanoplates, single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), and combinations thereof. In some examples, the cathode active material layer comprises LFP, Super P, and PTFE at a mass ratio of 96.5:1.5:2.
In some examples, the capacity loading of the cathode electrode is in a range from 2 to 6 mAh/cm2 (for single-sided coating 0.1C at room temperature). In some examples, the pressing density of the cathode electrode is in a range from 1.9 to 3.1 g/cm3 (e.g., 2.4 g/cm3). In some examples, the porosity is in a range from 25% to 45%. In some examples, the moisture content is less than 600 ppm. In some examples, the cathode electrodes have a width in a range from 50 mm to 500 mm. In some examples, the anode electrodes have a width in a range from 50 mm to 200 mm.
In some examples, the electrolyte comprises a lithium salt, a solvent, and an additive. In some examples, the lithium salt is selected from a group including LiPF6 or LiFSI (e.g., 0.82 mol/L). In some examples, the solvent is selected from a group consisting of carbonate ester or ether. In some examples, the additives are selected from a group consisting of fluoroethylene carbonate (FEC), dimethyl carbonate (DMC), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropylether (TTE), and/or other additives. For example, the electrolyte may comprise 1 M LiPF6 in FEC and DMC (1:4 volume) for a 1 Ah LFP/Li 300 Cu mesh stacking pouch battery cell. For example, the electrolyte may comprise 1 M LiPF6 in FEC and DMC (1:4 volume) for a 1 Ah LFP/Li 100 Cu mesh stacking pouch battery cell.
In some examples, an N/P ratio is in a range from 1.5 to 1.7 (e.g., 1.66). In some examples, the battery cell has a pouch, prismatic, cylindrical, or other suitable format using stacking or winding.
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The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, 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 the disclosure can be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure.
Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”
In the figures, the direction of an arrow, as indicated by the arrowhead, generally demonstrates the flow of information (such as data or instructions) that is of interest to the illustration. For example, when element A and element B exchange a variety of information but information transmitted from element A to element B is relevant to the illustration, the arrow may point from element A to element B. This unidirectional arrow does not imply that no other information is transmitted from element B to element A. Further, for information sent from element A to element B, element B may send requests for, or receipt acknowledgements of, the information to element A.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202311484256.X | Nov 2023 | CN | national |
