Patent Application
20240170719
This application claims the benefit of Chinese Patent Application No. 202211399417.0, filed on Nov. 9, 2022. 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 gel membrane for a battery cell and a method for roll-to-roll hot casting of the gel membrane.
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. Manufacturers of EVs are pursuing increased energy density to increase the range of the EVs.
Lithium-ion battery (LIB) cells are currently used for high power density or high energy density applications. Solid-state battery (SSB) cells with solid electrolyte have improved characteristics as compared to LIB cells in terms of abuse tolerance and working temperature range. However, high volume manufacturing of the SSB with the solid electrolyte has proven to be challenging.
A method for manufacturing a gel membrane for a battery cell includes supplying a first substrate to a first roller; heating a gel membrane solution in a tank, wherein the gel membrane solution includes a polymer and a liquid electrolyte comprising one or more lithium salts; arranging a slot die within a predetermined distance of the first substrate located on the first roller; pumping the gel membrane solution into an inlet of the slot die; depositing a gel membrane layer from an outlet of the slot die onto the first substrate supported by the first roller; and cooling the gel membrane layer on the first substrate.
In other features, a gap between the outlet of the slot die and the first substrate is in a range from 1 μm to 100 μm. The method includes arranging a second substrate over an exposed surface of the gel membrane layer. The polymer is in a range from 10 to 50 wt % of the gel membrane solution and the liquid electrolyte is in a range from 50 to 90 wt % of the gel membrane solution.
In other features, the polymer is selected from a group consisting of poly(ethylene oxide) (PEO), poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP), poly(methyl methacrylate) (PMMA), carboxymethyl cellulose (CMC), polyacrylonitrile (PAN), polyvinylidene difluoride (PVDF), poly(vinyl alcohol) (PVA), and polyvinylpyrrolidone (PVP).
In other features, the liquid electrolyte comprises a dual lithium salt, a solvent, and an electrolyte additive. The dual lithium salt comprises at least one lithium cation and at least one anion selected from a group consisting of hexafluoroarsenate, hexafluorophosphate, bis(fluorosulfonyl)imide (FSI), perchlorate, tetrafluoroborate, cycle-difluoromethane-1,1-bis(sulfonyl)imide (DMSI), bis(trifluoromethanesulfonyl)imide (TFSI), bis(perfluoroethanesulfonyl)imide (BETI), bis(oxalate)borate (BOB), difluoro(oxalate)borate (DFOB), and bis(fluoromalonato)borate (BFMB).
In other features, the solvent is selected from a group consisting of carbonate solvents, lactones, nitriles, sulfones, ethers, phosphates, and ionic liquids. The electrolyte additive is selected from a group consisting of 1,3,2-dioxathiolane 2,2-dioxide (DTD), vinyl ethylene carbonate (VEC), vinylene carbonate (VC), fluorosulfonyl isocyanate (FI), trimethyl borate (TMB), tris(trimethylsilyl) phosphate (TTSPi), methylene methane disulfonate (MMDS), and prop-1-ene-1,3-sultone (PES).
In other features, the method includes heating the tank to a first temperature in a range from 100 to 250° C. The method includes heating the slot die a second temperature in a range from 100 to 250° C. The gel membrane is cooled by dry gas at a temperature in a range from 10 to 60° C. The polymer includes polyacrylonitrile (PAN) and the liquid electrolyte includes LiTFSI, LiBF4, ethylene carbonate (EC), and γ-butyrolactone (GBL).
A battery cell, comprises a cathode electrode comprising a cathode current collector and cathode active material configured to exchange lithium ions. An anode electrode comprises an anode current collector and anode active material configured to exchange lithium ions. A gel membrane is arranged between the cathode electrode and the anode electrode and comprises a polymer and a liquid electrolyte comprising a dual lithium salt, a dual solvent, and an electrolyte additive.
In other features, the polymer is in a range from 10 to 50 wt % of the gel membrane and the liquid electrolyte is in a range from 50 to 90 wt % of the gel membrane. The polymer is selected from a group consisting of poly(ethylene oxide) (PEO), poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP), poly(methyl methacrylate) (PMMA), carboxymethyl cellulose (CMC), polyacrylonitrile (PAN), polyvinylidene difluoride (PVDF), poly(vinyl alcohol) (PVA), and polyvinylpyrrolidone (PVP).
In other features, the dual lithium salt comprises at least one lithium cation and at least one anion selected from a group consisting of hexafluoroarsenate, hexafluorophosphate, bis(fluorosulfonyl)imide (FSI), perchlorate, tetrafluoroborate, cycle-difluoromethane-1,1-bis(sulfonyl)imide (DMSI), bis(trifluoromethanesulfonyl)imide (TFSI), bis(perfluoroethanesulfonyl)imide (BETI), bis(oxylate)borate (BOB), difluoro(oxolate)borate (DFOB), and bis(fluoromalonato)borate (BFMB).
In other features, the dual solvent is selected from a group consisting of carbonate solvents, lactones, nitriles, sulfones, ethers, phosphates, and ionic liquids.
In other features, the electrolyte additive is selected from a group consisting of 1,3,2-dioxathiolane 2,2-dioxide (DTD), vinyl ethylene carbonate (VEC), vinylene carbonate (VC), fluorosulfonyl isocyanate (FI), trimethyl borate (TMB), tris(trimethylsilyl) phosphate (TTSPi), methylene methane disulfonate (MMDS), and prop-1-ene-1,3-sultone (PES).
In other features, the polymer includes polyacrylonitrile (PAN), the dual lithium salt includes LiTFSI and LiBF4, and the dual solvent includes ethylene carbonate (EC) and γ-butyrolactone (GBL).
In other features, a solid electrolyte layer arranged between the cathode electrode and the anode electrode.
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 the battery cells according to the present disclosure are described below in the context of a vehicle, the battery cells according to the present disclosure can be used in other applications.
Solid-state battery (SSB) cells with solid electrolyte (SE) have improved characteristics as compared to LIB cells in terms of abuse tolerance, and working temperature range. The SE may include oxides having high ionic conductivity and good oxidative stability. However, oxide SE is rigid and physical contact between the oxide SE layer and the surrounding electrode layers is poor due to high interfacial resistance. In addition, the physical contact is gradually weakened due to volumetric change of electrode material during cycling. As a result, performance deteriorates with use.
A free-standing gel membrane according to the present disclosure has high ionic conductivity and good stretching ability. The gel membrane provides favorable electrode/electrolyte interfacial contact and endows the battery cell with excellent power capability and cyclability. The gel membrane can be fabricated using roll-to-roll hot casting of a gel precursor solution. In some examples, the gel precursor solution comprises a polymer, a dual salt, and a dual solvent. In some examples, the polymer includes polyacrylonitrile (PAN), the dual salt includes LiTFSI and LiBF4, and the dual solvent includes ethylene carbonate (EC) and γ-butyrolactone (GBL), although other compositions are described further below.
Referring now to
When the solid electrolyte layer 24 includes oxide SE, performance of the battery cell suffers. Oxide SE is normally rigid and has a large grain boundary resistance which leads to poor solid-solid interfacial contact and poor power capability. Some oxides (such as LATP) cannot directly work with low operating voltage anodes (such as graphite) due to its high reductive limit (e.g., 1.7V). After cycling, the volumetric changes of the electrode active material further deteriorate the interfacial contact and reduce cycling performance.
Referring now to
In
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A conduit 312 connects the tank 310 to an inlet of a pump 314. An outlet of the pump 314 supplies the gel membrane solution via a conduit 316 to an inlet of a slot die 318. A substrate roller 324 supplies a substrate 326 (e.g., a polymer film) onto a roller 328. The substrate 326 is used to prevent sticking between layers of the gel membrane as it is cooled and dried. An outlet of the slot die 318 applies a thin layer of the gel membrane solution onto the substrate 326 supported by a roller 328. In some examples, the slot die 318 is heated to a temperature in a range from 100° C. to 250° C. with a gap between the slot die 318 and the roller 322 in a range from 1 μm to 100 μm.
The gel membrane can be cooled naturally in atmospheric conditions and/or cooled using a cooling device 334. In some examples, the substrate and the gel membrane (collectively identified at 332) pass through the cooling device 334 and are cooled and fully or partially solidified by the cooling device 334. In some examples, the cooling device 334 chills the gel membrane using cooled gas such as dry air at a temperature in a predetermined range from 10° C. to 60° C.
The substrate and the gel membrane 332 are guided by a roller 340 between rollers 346 and 348. A substrate roller 350 supplies a substrate 352 (e.g., such as polymer film) between the rollers 346 and 348. In other words, the gel membrane is sandwiched between the substrate 326 and the substrate 352 (collectively identified at 354) to prevent sticking. The substrate 326, the gel membrane, and the substrate 352 are wound onto a roller 356. Prior to usage of the gel membrane in a battery cell, the substrate 326 and the substrate 352 are removed.
Battery cells including the gel membrane according to the present disclosure have improved ionic conductivity, capacity retention, and capacity. As can be appreciated, roll-to-roll hot casting of the membrane is scalable and can be used to continuously manufacture the gel membrane.
In some examples, the gel membrane solution comprises a polymer in a range from 0.1 to 50 wt % and a liquid electrolyte in a range from 50 to 90 wt %. In some examples, the liquid electrolyte includes a mixture including a dual lithium salt, a dual solvent, and electrolyte additives. In some examples, the liquid electrolyte includes a dual lithium salt including 0.1 to 2.0M LiTFSI and 0.1 to 2.0 M LiBF4. In some examples, the dual solvent includes ethylene carbonate (EC) and γ-butyrolactone (GBL) equal to (10-x):x(w/w, 0.5<x<9.5)]%. In some examples, the electrolyte additive is in a range from 0 to 10 wt %. In some examples, the gel membrane solution comprises 13 wt % PAN, 87 wt % [0.4M LiTFSI, 0.4M LiBF4 in EC/GBL=4:6 (w/w)].
In some examples, the polymer is selected from a group consisting of poly(ethylene oxide) (PEO), poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP), poly(methyl methacrylate) (PMMA), carboxymethyl cellulose (CMC), polyacrylonitrile (PAN), polyvinylidene difluoride (PVDF), poly(vinyl alcohol) (PVA), and polyvinylpyrrolidone (PVP).
In some examples, the dual lithium salt comprises at least lithium cation and at least one anion selected from a group consisting of hexafluoroarsenate, hexafluorophosphate, bis(fluorosulfonyl)imide (FSI), perchlorate, tetrafluoroborate, cycle-difluoromethane-1,1-bis(sulfonyl)imide (DMSI), bis(trifluoromethanesulfonyl)imide (TFSI), bis(perfluoroethanesulfonyl)imide (BETI), bis(oxalate)borate (BOB), difluoro(oxalate)borate (DFOB), and bis(fluoromalonato)borate (BFMB).
The solvent in the gel membrane dissolves the lithium solvent to enable good lithium-ion conductivity and relatively low vapor pressure to match the fabrication process. In some examples, the solvent comprises carbonate solvents, lactones, nitriles, sulfones, ethers, phosphates, and ionic liquids.
Examples of carbonate solvents include ethylene carbonate (EC), propylene carbonate (PC), glycerol carbonate, vinylene carbonate, fluoroethylene carbonate, and 1,2-butylene carbonate. Examples of lactones include γ-butyrolactone (GBL) and δ-valerolactone. Examples of nitriles include succinonitrile, glutaronitrile, and adiponitrile. Examples of sulfones include tetramethylene sulfone, ethyl methyl sulfone, vinyl sulfone, phenyl sulfone, 4-fluorophenyl sulfone, and benzyl sulfone. Examples of ethers include triethylene glycol dimethylether (triglyme, G3), tetraethylene glycol dimethylether (tetraglyme, G4), 1,3-dimethoxy propane, and 1,4-dioxane. Examples of phosphates include triethyl phosphate and trimethyl phosphate.
Examples of ionic liquids include ionic liquid cations and ionic liquid anions. Examples of ionic liquid cations include 1-ethyl-3-methylimidazolium [Emim]+, 1-propyl-1-methylpiperidinium [PP13]+, 1-butyl-1-methylpiperidinium [PP14]+, 1-methyl-1-ethylpyrrolidinium [Pyr12]+, 1-propyl-1-methylpyrrolidinium [Pyr13]+, and 1-butyl-1-methylpyrrolidinium [Pyr14]+. Examples of ionic liquid anions include bis(fluorosulfonyl)imide (FSI) and bis(trifluoromethanesulfonyl)imide (TFSI).
In some examples, the electrolyte additive is selected from a group consisting of 1,3,2-dioxathiolane 2,2-dioxide (DTD), vinyl ethylene carbonate (VEC), vinylene carbonate (VC), fluorosulfonyl isocyanate (FI), trimethyl borate (TMB), tris(trimethylsilyl) phosphate (TTSPi), methylene methane disulfonate (MMDS), and prop-1-ene-1,3-sultone (PES).
In some examples, the cathode active material is selected from a group consisting of rock salt layered oxides, spinel, polyanion cathode materials, and surface-coated and/or doped cathode materials. Examples of rock salt layered oxides include LiCoO2, LiNixMnyCo1-x-yO2, LiNixMnyAl1-x-yO2, LiNixMn1-xO2, and Li1+xMO2. Examples of spinel include LiMn2O4, LiNi0.5Mn1.5O4. Examples of polyanion cathode include LiV2(PO4)3). In other examples, the cathode active material includes other lithium transition-metal oxides. Surface-coated and/or doped cathode materials such as LiNbO3-coated LiMn2O4, Li2ZrO3 or Li3PO4-coated LiNixMnyCo1-x-yO2, and Al-doped LiMn2O4. In other examples, low voltage cathode material such as lithiated metal oxide/sulfide (e.g., LiTiS2), lithium sulfide, or sulfur can be used.
In some examples, the conductive additive is selected from a group consisting of carbon black, graphite, graphene, graphene oxide, Super P, acetylene black, carbon nanofibers, carbon nanotubes and other electronically conductive additives.
In some examples, the solid electrolyte is selected from a group consisting of oxide-based solid electrolyte, metal-doped or aliovalent substituted oxide solid electrolyte, sulfide-based solid electrolyte, nitride-based solid electrolyte, hydride-based solid electrolyte, halide-based solid electrolyte, borate-based solid electrolyte, and inactive ceramic oxides.
Examples of oxide-based solid electrolytes include garnet type (e.g., Li7La3Zr2O12), perovskite type (e.g., Li3xLa2/3-xTiO3), NASICON type (e.g., Li1.4Al0.4Ti1.6(PO4)3 and Li1+xAlxGe2-x(PO4)3), and LISICON type (e.g., Li2+2xZn1-xGeO4).
Examples of metal-doped or aliovalent substituted oxide solid electrolytes include Al or Nb-doped Li7La3Zr2O12, Sb-doped Li7La3Zr2O12, Ga-substituted Li7La3Zr2O12, Cr and V-substituted Li7La3Zr2O12, Al-substituted perovskite, and Li1+x+yAlxTi2-xSiyP3-yO12.
In some examples, the sulfide-based solid electrolyte is selected from a group consisting of pseudobinary sulfide, pseudoternary sulfide, and pseudoquaternary sulfide. Examples of pseudobinary sulfide include Li2S—P2S5 system (Li3PS4, Li7P3S11 and Li9.6P3S12), Li2S—SnS2 system (Li4SnS4), Li2S—SiS2 system, Li2S—GeS2 system, Li2S—B2S3 system, Li2S—Ga2S3 system, Li2S—P2S3 system, Li2S—Al2S3 system. Examples of pseudoternary sulfide include Li2O—Li2S—P2S5 system, Li2S—P2S5—P2O5 system, Li2S—P2S5—GeS2 system (Li3.25Ge0.25P0.75S4 and Li10GeP2S12), Li2S—P2S5—LiX (X=F, Cl, Br, I) system (Li6PS5Br, Li6PS5Cl, L7P2S8I and Li4PS4I), Li2S—As2S5—SnS2 system (Li3.833Sn0.833As0.166S4), Li2S—P2S5—Al2S3 system, Li2S—LiX—SiS2 (X=F, Cl, Br, I) system, 0.4·0.6Li4SnS4 and Li11Si2PS12. Examples of pseudoquaternary sulfide include Li2O—Li2S—P2S5—P2O5 system, Li9.54S11.74P1.44S11.7Cl0.3, Li7P2.9Mn0.1S10.7I0.3 and Li10.35[Sn0.27Si1.08]P1.65S12.
Examples of nitride-based solid electrolyte includes Li3N, Li7PN4, and LiSi2N3.
Examples of halide-based solid electrolyte includes Li3YCl6, Li3InCl6, Li3YBr6, LiI, Li2CdCl4, Li2MgCl4, Li2CdI4, Li2ZnI4, Li3OCl. Examples of hydride-based solid electrolyte include LiBH4, LiBH4—LiX (X=Cl, Br, or I), LiNH2, Li2NH, LiBH4—LiNH2, Li3AlH6.
Examples of borate based solid electrolyte include Li2B4O7, Li2B4O7, and Li2O—B2O3—P2O5.
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 |
|---|---|---|---|
| 202211399417.0 | Nov 2022 | CN | national |
