Dry electrode fabrication for solid-state energy storage devices

Abstract

A method of manufacturing an electrode block for a solid-state battery includes providing an electrode film having a current collector on a first side of the electrode film, coating a layer of dry electrolyte powder on a second side of the electrode film opposite the first side, and pressing the dry electrolyte powder coated on the electrode film to produce a solid electrolyte layer on the electrode film. A method of manufacturing an electrolyte film for a solid-state battery includes preparing a powder mixture including at least one type of fibrillizable binder and at least one type of dry electrolyte powder, the at least one type of dry electrolyte powder being a majority of the powder mixture by weight, fibrillizing the at least one type of fibrillizable binder in the powder mixture by subjecting the powder mixture to a shear force, and pressing the powder mixture into a free-standing film.

Description

[Background technology]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application is a continuation-in-part of U.S. Patent Application No. 17 / 492,458, filed October 1, 2021, and entitled "DRY ELECTRODE MANUFACTURE FOR SOLID STATE ENERGY STORAGE DEVICES," the entire disclosure of which is incorporated herein by reference. [STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT]

[0002] Not applicable

[0003] 1.Technical Field

[0004] The present disclosure relates generally to manufacturing energy storage devices such as Li-ion batteries, and more particularly to dry processes for manufacturing solid-state batteries.

[0005] 2. Related technologies

[0006] Due to safety concerns surrounding the use of flammable liquid electrolytes in Li-ion batteries and other energy storage devices, and to take advantage of the high energy densities achievable using Li metal anodes, much attention has been focused on developing solid-state batteries and other energy storage devices. In solid-state batteries, traditional liquid electrolytes and separators are replaced with ceramic or solid polymer electrolytes. Unfortunately, electrolyte materials tend to be affected by N-methylpyrrolidone (NMP) or other solvents used to form solid electrolyte films by using wet coating methods, resulting in reduced battery performance. Furthermore, current techniques for assembling solid-state batteries result in a substantial boundary layer between the solid electrolyte and the electrodes, making it difficult for electrolyte ions to pass through, thereby increasing battery resistance. Summary of the Invention

[0007] The present disclosure contemplates various methods and devices for overcoming the above-mentioned drawbacks associated with the related art. One aspect of an embodiment of the present disclosure is a method for manufacturing an electrode block for a solid-state battery. The method may include providing an electrode film having a current collector on a first surface of the electrode film, coating a layer of dry electrolyte powder on a second surface of the electrode film opposite the first surface, and pressing the dry electrolyte powder coated on the electrode film to produce a solid electrolyte layer on the electrode film.

[0008] Providing the electrode film with the current collector may include preparing a powder mixture comprising at least one type of electrode active material and at least one type of fibrillizable binder, fibrillating the at least one type of fibrillizable binder in the powder mixture by subjecting the powder mixture to a shear force, pressing the powder mixture into a free-standing film, and laminating the free-standing film onto the current collector. The powder mixture may further comprise at least one type of dry electrolyte powder.

[0009] Another aspect of an embodiment of the present disclosure is a method of manufacturing a solid-state battery, which may include providing a first electrode film having a first surface and a second surface opposite the first surface, providing a second electrode film having a first surface and a second surface opposite the first surface, coating the second surface of the first electrode film with a layer of dry electrolyte powder, disposing the second surface of the second electrode film on the layer of dry electrolyte powder, and pressing the first electrode film with the layer of dry electrolyte powder coated thereon together with the second electrode film to produce a solid-state battery comprising the first electrode film, the second electrode film, and a solid electrolyte layer therebetween.

[0010] Either or both of the steps of providing the first electrode film and providing the second electrode film may include preparing a powder mixture comprising at least one type of electrode active material and at least one type of fibrillizable binder, fibrillating the at least one type of fibrillizable binder in the powder mixture by subjecting the powder mixture to a shear force, and pressing the powder mixture into a free-standing film. The powder mixture may further comprise at least one type of dry electrolyte powder.

[0011] The method may further include laminating the first electrode film onto a first current collector with the first current collector on the first side of the first electrode film, and laminating the second electrode film onto a second current collector with the second current collector on the first side of the second electrode film. The laminating of the first electrode film and the laminating of the second electrode film may be performed before the coating step or after the pressing step.

[0012] Another aspect of an embodiment of the present disclosure is a method for manufacturing an electrode membrane for a solid-state battery, which may include preparing a powder mixture including at least one type of electrode active material, at least one type of fibrillizable binder, and at least one type of dry electrolyte powder, wherein the at least one type of dry electrolyte powder is 5-30 wt % of the powder mixture, fibrillating the at least one type of fibrillizable binder in the powder mixture by subjecting the powder mixture to a shear force, and pressing the powder mixture into a free-standing membrane.

[0013] The method may comprise the step of adding a solvent to the powder mixture to activate the at least one type of fibrillizable binder prior to the step of fibrillating.

[0014] The method may comprise, prior to the fibrillating step, heating the powder mixture to 70° C. or higher to activate the at least one type of fibrillizable binder.

[0015] The powder mixture may comprise an additive solution having a polymeric additive and a liquid carrier, the additive solution being less than 5% by weight of the powder mixture.

[0016] The powder mixture may comprise a conductive paste having a polymer additive, a liquid carrier, and a conductive material, the conductive paste being less than 5% by weight of the powder mixture.

[0017] Another aspect of an embodiment of the present disclosure is a free-standing electrode membrane, which may comprise at least one type of electrode active material, at least one type of fibrillizable binder, and at least one type of dry electrolyte powder in an amount of 5 to 30% by weight of the free-standing electrode membrane.

[0018] Another aspect of an embodiment of the present disclosure is a method for manufacturing an electrolyte membrane for a solid-state battery, which may include preparing a powder mixture comprising at least one type of fibrillizable binder and at least one type of dry electrolyte powder, wherein the at least one type of dry electrolyte powder constitutes a majority of the powder mixture by weight (e.g., 80% by weight or more of the powder mixture, e.g., 80-97% by weight or 80-99% by weight, preferably 95-99% by weight), subjecting the powder mixture to a shear force to fibrillate the at least one type of fibrillizable binder in the powder mixture, and pressing the powder mixture into a free-standing membrane.

[0019] The method may comprise the step of adding a solvent to the powder mixture to activate the at least one type of fibrillizable binder prior to the step of fibrillating.

[0020] The method may comprise, prior to the fibrillating step, heating the powder mixture to 70° C. or higher to activate the at least one type of fibrillizable binder.

[0021] The powder mixture may comprise an additive solution having a polymeric additive and a liquid carrier, the additive solution being less than 5% by weight of the powder mixture.

[0022] Another aspect of an embodiment of the present disclosure is a method for manufacturing an electrode block for a solid-state battery, which may include carrying out the above-described method for manufacturing the electrolyte membrane, providing the electrode membrane (with or without a current collector), and laminating the free-standing electrolyte membrane onto the electrode membrane.

[0023] Another aspect of the present disclosure is a free-standing electrolyte membrane. The free-standing electrolyte membrane may include at least one type of fibrillizable binder and at least one type of dry electrolyte powder. The at least one type of dry electrolyte powder may constitute a majority of the free-standing electrolyte membrane by weight. For example, the dry electrolyte powder may account for 80% or more by weight of the free-standing electrolyte membrane, for example, 80 to 97% by weight or 80 to 99% by weight, preferably 95 to 99% by weight.

[0024] Another aspect of an embodiment of the present disclosure is a method for manufacturing an electrode block for a solid-state battery, which may include laminating the above-described free-standing electrolyte membrane onto an electrode membrane. [Brief explanation of the drawings]

[0025] These and other features and advantages of the various embodiments disclosed herein will be better understood with regard to the following description and drawings, in which like numerals refer to like parts throughout.

[0026] [Figure 1] FIG. 1 is a diagram of an apparatus for manufacturing electrode blocks for solid-state batteries.

[0027] [Figure 1A] FIG. 2 is an enlarged view of an electrode block.

[0028] [Figure 2] FIG. 1 is a diagram of an apparatus for manufacturing a solid-state battery.

[0029] [Figure 2A] FIG. 2 is an enlarged view of a solid-state battery.

[0030] [Figure 3] 1 is a workflow for manufacturing an electrode block.

[0031] [Figure 4] 1 is a workflow for manufacturing a solid-state battery.

[0032] [Figure 5] 4 is a workflow for manufacturing an electrode film, and is an exemplary sub-workflow of step 310 in FIG. 3, step 410 in FIG. 4, or step 420 in FIG.

[0033] [Figure 6] 1 is a workflow for manufacturing an electrolyte membrane. DETAILED DESCRIPTION OF THE INVENTION

[0034] The present disclosure encompasses various embodiments of solid-state batteries and electrodes, as well as methods of manufacture and intermediate products thereof. The detailed description set forth below in connection with the accompanying drawings is intended as a description of several currently contemplated embodiments and is not intended to represent the only manner in which the disclosed invention(s) may be developed or utilized. This description describes functions and features in connection with the illustrated embodiments. However, it should be understood that the same or equivalent functions may be achieved by different embodiments that are also intended to be encompassed within the scope of the present disclosure. It should be further understood that the use of relational terms such as first and second and like are used merely to distinguish one entity from another, without necessarily requiring or implying any actual such relationship or order between such entities.

[0035] FIG. 1 shows an apparatus 10 for manufacturing an electrode block 100 for a solid-state battery. FIG. 1A is an enlarged view showing the electrode block 100, which may include an electrode film 110 and a solid electrolyte layer 120 laminated thereon. The electrode block 100 may be stacked and / or wound with additional electrode blocks 100 to manufacture a multi-layer battery, such as a cylindrical or prismatic cell. As shown, the apparatus 10 may include one or more pieces of roll-to-roll processing equipment, such as a first spool 12 onto which the electrode film 110 may be initially wound as a roll, a second spool 14 onto which the final electrode block 100 may be wound, and one or more rollers 16 (e.g., drive and / or idler rollers) for conveying the electrode film 110 through the apparatus 10 from the first spool 12 to the second spool 14. 1 may include a scatter coater 11 or other means for coating one side 114 of the electrode film 110 with a layer of dry electrolyte powder 119, which may then be pressed by a roller press or calender 18 to produce a solid electrolyte layer 120 on the electrode film 110. In this manner, the solid electrolyte layer 120 may be formed in a dry process, avoiding significant amounts of NMP or other solvents used in conventional slurry-based processes that may otherwise degrade the performance of the solid electrolyte. Furthermore, because the solid electrolyte layer 120 is formed directly on the electrode film 110 rather than subsequently stacked thereon, the resulting interface between the electrode film 110 and the solid electrolyte layer 120 may be easier for electrolyte ions to pass through, reducing battery resistance.

[0036] The electrode film 110 may be either a cathode film or an anode film and may include an active material layer suitable for a cathode or an anode, respectively. To assemble a multilayer battery, electrode blocks 100 having cathode and anode electrode films 110 may be stacked, typically in an alternating manner, with a solid electrolyte layer 120 separating each cathode from the adjacent anode and each anode from the adjacent cathode. For ease of illustration, the electrode film 110 is shown as having only a single layer, i.e., an active material layer (e.g., 50 μm to 350 μm), with a dry electrolyte powder 119 coated on one side 114 thereof. However, a current collector (e.g., 8 μm to 30 μm), such as an aluminum metal sheet in the case of the cathode electrode film 110 or a copper metal sheet in the case of the anode electrode film 110, may be laminated on the opposite side 112. Although not shown separately, this current collector may be present for the process illustrated in Figure 1 to help provide stability during pressing of the dry electrolyte powder 119 into the solid electrolyte layer 120, and may be in the final electrode block 100 shown in Figure 1A. It is also contemplated, although typically less practical, that the current collector may be laminated to the electrode block 100 after the process of Figure 1 rather than before.

[0037] FIG. 2 illustrates an apparatus 20 for manufacturing a solid-state battery 200. FIG. 2A is an enlarged view of the solid-state battery 200, which may include a first electrode film 210, a solid electrolyte layer 220, and a second electrode film 230, in the order shown. The apparatus 20 may be largely identical to the apparatus 10 of FIG. 1 and may similarly include a first spool 12 onto which the first electrode film 210 may initially be wound as a roll, a second spool 14 onto which the final product, in this case the solid-state battery 200, may be wound, one or more rollers 16, a roller press or calender 18, and a scatter coater 11 or other means. The apparatus 20 may differ from the apparatus 10 in the addition of a third spool 22 onto which the second electrode film 230 may initially be wound as a roll. In the apparatus 20, a scatter coater 11 may coat a layer of dry electrolyte powder 119 onto one side 214 of a first electrode film 210, after which one side 234 of a second electrode film 230 may be disposed on the layer of dry electrolyte powder 119. Using a roller press or calender 18, the first electrode film 210 with the layer of dry electrolyte powder 119 coated thereon may then be pressed with the second electrode film 230 to produce a solid-state battery 200 including the first electrode film 210, the second electrode film 230, and the solid electrolyte layer 220 therebetween.

[0038] While the apparatus 10 shown in FIGS. 1 and 1A can produce individual electrode blocks 100 for use in a multilayer battery, the apparatus 20 in FIGS. 2 and 2A can produce a final single-layer solid-state battery 200 having only one cathode and one anode. Such a single-layer solid-state battery 200 can be packaged, for example, as a pouch cell or a button cell. Note that either one of the first and second electrode layers 210, 230 can be the cathode and the other the anode. That is, the dry electrolyte powder 119 can be coated onto either the cathode or the anode before being sandwiched and pressed with the other to form the solid electrolyte layer 220.

[0039] Again, for ease of illustration, the electrode film 210 is illustrated as having only a single layer, i.e., an active material layer, with dry electrolyte powder 119 coated on one side 214 thereof. Similarly, the electrode film 230 is illustrated as having only an active material layer, with one side 234 shown disposed in contact with the dry electrolyte powder 119. As noted above, a current collector, such as an aluminum metal sheet in the case of the cathode electrode films 210, 230, or a copper metal sheet in the case of the anode electrode films 210, 230, may be laminated on the opposite side 212, 232, and it should be understood that such a current collector may be present for the process illustrated in FIG. 2 and in the final solid-state battery 200 shown in FIG. 2A. However, it is contemplated that the process of FIG. 2 may actually proceed without the presence of a current collector on the electrode films 210, 230, as some single-cell batteries 200, such as coin cells that utilize the metal of the case for this purpose, may not have a current collector. In this regard, the process of Figure 2 may actually require less metal current collector layers, as the additional electrode film 230 may provide some stability during pressing compared to the process of Figure 1. Thus, if current collectors are to be used in the final solid-state battery 200, the electrode films 210, 230 may be laminated onto the respective current collectors either before coating with the dry electrolyte powder 119 (and thus before pressing) or after pressing.

[0040] 3 is a workflow for manufacturing an electrode block, such as the electrode block 100 shown in FIG. 1A. The workflow may begin with providing an electrode film 110 (step 310), which may typically be laminated onto a current collector as described above. The electrode film 110 may be produced by any method, including, for example, slurry coating, extrusion, and dry processes. Advantageously, dry methods may be used, such as any of the methods described in the inventor's own prior patents and patent applications, including U.S. Pat. No. 10,069,131, entitled "Electrode for Energy Storage Devices and Method of Making Same," U.S. Patent Application Publication No. 2020 / 0388822, entitled "Dry Electrode Manufacture by Temperature Activation Method," U.S. Patent Application No. 17 / 014,862, entitled "Dry Electrode Manufacture with Lubricated Active Material Mixture," and U.S. Patent Application No. 17 / 097,200, entitled "Dry Electrode Manufacture with Composite Binder," the entire disclosures of each of which are incorporated herein by reference in their entirety.As will be described in more detail below, in particular, the electrode film 110 can be produced by preparing a powder mixture including at least one type of electrode active material (e.g., lithium metal oxide for the cathode or graphite for the anode) and at least one type of fibrillizable binder, such as polytetrafluoroethylene (PTFE), polyvinylpyrrolidone (PVP), polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), or carboxymethylcellulose (CMC), fibrillizing the binder by subjecting the powder mixture to a shear force, and pressing the powder mixture into a free-standing film that can then be laminated onto a current collector.

[0041] 3 may continue with coating a layer of dry electrolyte powder 119 (Step 320) on a second surface 114 of the electrode film 110 opposite the first surface 112. As illustrated in FIG. 1 , coating the dry electrolyte powder 119 on the electrode film 110 may be part of a roll-to-roll process exemplified by apparatus 10, in which a scatter coater 11 coats the dry electrolyte powder 119 on the electrode film 110 as the electrode film 110 is transported by one or more rollers 16 from a first spool 12 to a second spool 14. The workflow may conclude with pressing the coated dry electrolyte powder 119 on the electrode film 110 to produce a solid electrolyte layer 120 on the electrode film 110 (Step 330). 1, for example, as the dry electrode film 110 passes through the apparatus 10 from the first spool 12 to the second spool 14, a roller press or calender 18 can press the dry electrolyte powder 119 onto the electrode film 110 to produce a solid electrolyte layer 120. A completed electrode block 100 that can be used to produce a multilayer battery as described above can be as illustrated in FIG. 1A (with current collectors omitted for ease of illustration).

[0042] 4 is a workflow for manufacturing a solid-state battery such as the solid-state battery 200 shown in FIG. 2A. The workflow may begin with providing a first electrode film 210 and a second electrode film 230 (steps 410 and 420). Similar to the electrode film 110 described above, the electrode films 210, 230 may be produced by any method, including, for example, a slurry coating method, an extrusion method, and a dry method, including any of the methods described in the inventor's own prior patents and patent applications, such as those incorporated by reference above. In particular, as described in more detail below, each of the electrode films 210, 230 can be produced by preparing a powder mixture including at least one type of electrode active material (e.g., lithium metal oxide for the cathode or graphite for the anode) and at least one type of fibrillizable binder, such as PTFE, PVP, PVDF, PEO, or CMC, fibrillating the binder by subjecting the powder mixture to a shear force, and pressing the powder mixture into a free-standing film that can then be laminated onto a current collector. If the first electrode film 210 is composed of a cathode active material, the second electrode film 230 can be composed of an anode active material. If the first electrode film 210 is composed of an anode active material, the second electrode film 230 can be composed of a cathode active material.

[0043] 4 may continue with coating (step 430) a layer of dry electrolyte powder 119 onto the second surface 214 of the first electrode film 210, opposite the first surface 212. As illustrated in FIG. 2, the coating of the dry electrolyte powder 119 onto the electrode film 210 may be part of a roll-to-roll process exemplified by apparatus 20, in which a scatter coater 11 coats the dry electrolyte powder 119 onto the first electrode film 210 (which may be either the cathode or anode) as the first electrode film 210 is transported by one or more rollers 16 from a first spool 12 to a second spool 14. After the dry electrolyte powder 119 is coated onto the first electrode film 210, the workflow may continue with disposing a second electrode film 230 on the layer of dry electrolyte powder 119. In particular, the second surface 234 of the second electrode film 230 (i.e., the surface opposite the first surface 232 having the optional current collector) may be positioned near the layer of dry electrolyte powder 119, as shown in FIG. 2 , such that the first and second electrode films 210, 230 sandwich the layer of dry electrolyte powder 119. The workflow may continue with pressing (e.g., using a roller press or calender 18) the first electrode film 210, with the second electrode film 230, onto which the layer of dry electrolyte powder 119 has been coated, to produce a solid-state battery 200 including the first electrode film 210, the second electrode film 230, and the solid electrolyte layer 220 therebetween (step 450). The completed solid-state battery 200, which may be a single layer battery as described above, may be as illustrated in FIG. 2A.

[0044] The workflow of FIG. 4 may conclude with laminating the first electrode film 210 onto a first current collector (e.g., an aluminum metal sheet for the cathode or a copper metal sheet for the anode), and similarly, laminating the second electrode film 230 onto a second current collector (steps 460, 470). These steps may follow step 450 as shown in FIG. 4, with the completed solid-state battery 200 then being laminated to the respective current collectors on both of the exterior surfaces 212, 232. Alternatively, one or both of steps 460 and 470 may precede step 430, such that the electrode films 210, 230 are laminated to their respective current collectors before being coated with the dry electrolyte powder 119 as described above. In this case, FIG. 2A omits such optional current collectors for ease of illustration. Alternatively, steps 460 and 470 may be omitted entirely, which may be useful when manufacturing certain button cells that do not use current collectors.

[0045] The dry electrolyte powder 119 used in either of the work flows of FIGS. 3 and 4 (and by either of the apparatuses 10, 20) is primarily (e.g., 80-100 wt.%) garnet-structure oxides, such as lithium lanthanum zirconium oxide (LLZO) (e.g., Li 6.5 La3Zr2O 12 or Li7La3Zr2O 12 ), lithium lanthanum zirconium tantalum oxide (LLZTO) (e.g., Li 6.4 La3Z 1.4 Ta 0.6 O 12 ), lithium lanthanum zirconium niobium oxide (LLZNbO) (e.g., Li 6.5 La3Zr 1.5 Nb 0.5 O 12), lithium lanthanum zirconium tungsten oxide (LLZWO) (e.g., Li 6.3 La3Zr 1.65 W 0.35 O 12 ), perovskite structure oxides, for example, lithium lanthanum titanate (LLTO) (for example, Li 0.5 La 0.5 TiO3, Li 0.34 La 0.56 TiO3 or Li 0.29 La 0.57 TiO3) or lithium aluminum titanium phosphate (LATP) (e.g., Li 1.4 Al 0.4 Ti 1.6 (PO4)3), lithium superionic conductor Li 2+2x Zn 1-x GeO4 (lithium super ionic conductor: LISICON), for example, lithium aluminum titanium phosphate (LATP) (e.g., Li 1.3 Al 0.3 Ti 1.7 (PO4)3), lithium aluminum germanium phosphate (LAG or sodium superionic conductor, i.e., NASICON-type LAGP) (e.g., Li 1.5 Al 0.5 Ge 1.5 (PO4)3 or Li 1.5 Al 0.5 Ge 1.5 P3O 12 ) or phosphates, such as lithium titanium phosphate (LTPO) (e.g., LiTi2(PO4)3), lithium germanium phosphate (LGPO) (e.g., LiGe2(PO4)3), lithium phosphate (LPO) (e.g., γ-Li3PO4 or Li7P3O 11), or a ceramic such as lithium phosphorus oxynitride (LiPON). As another example, the dry electrolyte powder 119 can be primarily (e.g., 80-100% by weight) a polymer such as PEO, PEO-PTFE, PEO-LiTFSi, PEO-LiTFSi / LLZO, PEO-LiClO4, PEO-LiClO4 / LLZO, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate: PEDOT:PSS), polyphenylene oxide (PPO), polyethylene glycol (PEG), polyether-based polymers, polyester-based polymers, nitrile-based polymers, polysiloxane-based polymers, polyurethane, poly(bis((methoxyethoxy)ethoxy)phosphazene) (poly-(bis((methoxyethoxy)ethoxy)phosphazene) (MEEP), or polyvinyl alcohol (PVA). As another example, the dry electrolyte powder 119 may be primarily (e.g., 80 to 100 wt%) composed of lithium sulfide (LS) (e.g., LiS), glassy lithium sulfide phosphorus sulfide (LSPS) (e.g., LiS-P2S5), glassy lithium sulfide boron sulfide (LSBS) (e.g., LiS-B2S3), glassy lithium sulfide silicon sulfide (LSSiS) (e.g., LiS-SiS2), lithium germanium sulfide (LGS) (e.g., Li4GeS4), lithium phosphorus sulfide (LPS) (e.g., Li3PS4, e.g., 75Li2S-25P2S5 or Li7P3S 11For example, 70Li2S-30P2S5), lithium silicon phosphorus tin sulfide (LSPTS) (for example, Li x (SiSn)P y S z ), argonium sulfide Li6PS5X (X=Cl, Br) (e.g., LPSBr, e.g., Li6PS5Br; LPSCl, e.g., Li6PS5Cl; LPSClBr, e.g., Li6PS5Cl 0.5 Br 0.5 , or LSiPSCl, e.g., Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 ) or thio-LISICON (e.g., LGPS, e.g., Li 10 GePS 12 ) and other sulfides.

[0046] FIG. 5 is a workflow for manufacturing an electrode film, such as the electrode film 110, 210, 230 described above. Thus, FIG. 5 may serve as an exemplary sub-workflow for step 310 in FIG. 3, step 410 in FIG. 4, or step 420 in FIG. 4. In particular, FIG. 5 provides one example of a dry process for producing a cathode or anode electrode film 110, 210, 230, which may be further used to produce an electrode block 100 for a multilayer battery according to the workflow of FIG. 3 or to produce a single-layer battery according to the workflow of FIG. 4. As noted above, producing the electrode film 110, 210, 230 by a dry process may generally involve preparing a powder mixture including at least one type of electrode active material and at least one type of fibrillizable binder, subjecting the powder mixture to shear forces to fibrillate the binder, and pressing the powder mixture into a free-standing film that can then be laminated onto a current collector. More specifically, the workflow of FIG. 5 may begin with preparing a powder mixture for the electrode films 110, 210, and 230 (step 510). The electrode active material may constitute a majority of the powder mixture, for example, 82 to 99 wt. % (e.g., 94 wt. %) of the powder mixture. For the cathode, the electrode active material may be a lithium metal oxide, such as lithium manganese oxide (LMO), lithium nickel manganese cobalt oxide (NCM), lithium nickel cobalt aluminum oxide (NCA), or lithium nickel manganese oxide (LMNO). For the anode, the electrode active material may be graphite, silicon dioxide (SiO), a mixture of the two, or the like. Depending on the conductivity of the active material, a conductive material may be added to the powder mixture in an amount of, for example, 0 to 10 wt. % (e.g., 4 wt. %).Exemplary conductive materials may include activated carbon, conductive carbon black such as acetylene black, ketjen black, or super P (e.g., carbon black sold under the trade name SUPER P® by Imerys Graphite & Carbon, Switzerland), carbon nanotubes (CNTs), graphite particles, conductive polymers, or combinations thereof.

[0047] To form the electrode films 110, 210, 230 by a dry process (thus avoiding the long drying times associated with conventional slurry coating and extrusion processes), the powder mixture may further include at least one type of fibrillizable binder, such as polytetrafluoroethylene (PTFE), polyvinylpyrrolidone (PVP), polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), or carboxymethylcellulose (CMC), including composite binders such as those described in U.S. Patent Application No. 17 / 097,200, entitled "Dry Electrode Manufacture with Composite Binder," incorporated by reference above. Fibrillizable binders may be characterized by their soft, pliable consistency and, in particular, by their ability to stretch, becoming longer and thinner and assuming a fibrous state when subjected to shear forces. Thanks to the use of one or more fibrillizable binders, which can be further chemically or thermally activated to increase their flexibility as described below, the powder mixture can be pressed into a free-standing film without breakage and without excessive use of solvents such as NMP.

[0048] As described in more detail in U.S. Patent Application No. 17 / 014,862, entitled "Dry Electrode Manufacture with Lubricated Active Material Mixture," incorporated by reference above, a powder mixture containing an electrode active material can be lubricated by mixing it in a polymer-containing additive solution or conductive paste before adding a binder. For example, the powder mixture can include an additive solution containing a polymer additive and a liquid carrier in addition to the electrode active material (and a subsequently added fibrillizable binder). The additive solution can be less than 5% by weight of the powder mixture, so that the powder mixture can remain a dry powder despite the relatively small amount of liquid added. For example, the final powder mixture containing the electrode active material, optional conductive material, fibrillizable binder, and additive solution, as well as optional electrolyte powder (see below), can have a total solids content of greater than 95% by weight. The polymer additive, which can be 0.5% to 10% by weight of the additive solution, can be a polymeric compound, a surfactant, or a high-viscosity liquid (e.g., mineral oil or wax), such as those known to be used as dispersants or binders for carbon nanotubes. See, for example, U.S. Patent No. 8,540,902, which provides exemplary dispersants and polymer binders including polyethylene, polypropylene, polyamide, polyurethane, polyvinyl chloride, polyvinylidene fluoride, thermoplastic polyester resin, polyvinylpyrrolidone, polystyrene sulfonate, polyphenylacetylene, polymeta-phenylene vinylene, polypyrrole, poly(p-phenylene benzobisoxazole), natural polymers, aqueous amphiphiles, anionic aliphatic surfactants, sodium dodecyl sulfate, cyclic lipopeptide biosurfactants, water-soluble polymers, polyvinyl alcohol sodium dodecyl sulfate, polyoxyethylene surfactants, polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), hydroxyethyl cellulose polyacrylic acid, polyvinyl chloride, and combinations thereof. Another exemplary polymer additive may be styrene-butadiene rubber (SBR).The liquid carrier used to form the additive solution may be aqueous or non-aqueous and may include, for example, one or more chemicals selected from the group consisting of n-methylpyrrolidone, hydrocarbons, acetates, alcohols, glycols, ethanol, methanol, isopropanol, acetone, diethyl carbonate, and dimethyl carbonate.

[0049] Alternatively, the powder mixture can include a conductive paste containing a polymer additive, a liquid carrier, and a conductive material in addition to the electrode active material (and the subsequently added fibrillizable binder). Similar to the additive solution described above, the conductive paste can be less than 5% by weight of the powder mixture. For example, a final powder mixture containing the electrode active material, fibrillizable binder, and conductive paste (typically, no separate conductive material is used in the powder mixture), as well as an optional electrolyte powder (see below), can have a total solids content of more than 95% by weight. The conductive paste can differ from the additive solution in the addition of a conductive material, e.g., 1-20% by weight, preferably 2-15% by weight, and more preferably 5-10% by weight of the conductive paste. The conductive paste can be, for example, a CNT paste conventionally used to enhance electrical conductivity in wet mixtures used in coating methods such as those exemplified by U.S. Pat. No. 8,540,902. As one example, the conductive paste may consist of 3.08% (by weight) PVP as the polymer additive, 91.67% (by weight) NMP as the liquid carrier, and 6.25% (by weight) carbon nanotubes as the conductive material.

[0050] The powder mixture can include at least one type of dry electrolyte powder so that in the final electrode block 100 or solid-state battery 200, the resulting electrode film 110, 210, 230 can more easily exchange electrolyte ions with the solid electrolyte layer 120, 220, thereby reducing battery resistance. The amount of dry electrolyte powder in the powder mixture can be, for example, 5 to 30 wt. %. The dry electrolyte powder included in the powder mixture can be the same as or different from the dry electrolyte powder 119 used to form the solid electrolyte layer 120, 220, and can be, for example, any of the materials listed above for the dry electrolyte powder 119.

[0051] Once a powder mixture containing the electrode active material, any additive solution or conductive paste for lubricating the electrode active material, the fibrillizable binder, any additional conductive materials, and advantageously at least one type of dry electrolyte powder has been prepared, the workflow of Figure 5 may continue with activating the fibrillizable binder by one or more activation methods. In the solvent activation step, a solvent may be added to the powder mixture to chemically activate the fibrillizable binder, softening it so that it can be stretched longer and thinner without breaking and improving its adhesive strength (step 520). Unlike solvents such as NMP, which can be difficult to remove and involve lengthy drying processes, the solvent added in the solvent activation step 520 may have a relatively low boiling point below 130°C or even below 100°C (i.e., below the boiling point of water). Exemplary solvents may include hydrocarbons (e.g., hexane, benzene, toluene), acetic acids (e.g., methyl acetate, ethyl acetate), alcohols (e.g., propanol, methanol, ethanol, isopropyl alcohol, butanol), glycols, acetone, dimethyl carbonate (DMC), diethylcarbamazine (DEC), tetrachloroethylene, etc. Unlike slurry coating and extrusion processes, where the solvent may be 60-80% by weight of the resulting wet mixture, the solvent added in step 520 may be less than 20% by weight of the resulting mixture. For example, the ratio of powder mixture to added solvent may be approximately 100:10, 100:5, or 100:3.

[0052] Instead of or in addition to the solvent activation step 520, the workflow can include a temperature activation step in which the powder mixture is heated to 70°C or higher, preferably 100°C or higher, to thermally activate the fibrillizable binder (step 530). Similar to the solvent activation step 520, the temperature activation step 530 can soften the fibrillizable binder, allowing it to stretch longer and thinner without breaking, improving its adhesive strength. The temperature to which the powder mixture is heated in the temperature activation step 530 can be below the glass transition temperature of the binder (e.g., 114.85°C for PTFE), since binder softening can occur before the glass temperature is reached. Alternatively, the mixture can be heated to a temperature equal to or exceeding the glass temperature of the binder. If both the solvent activation step 520 and the temperature activation step 530 are used, the two steps can proceed in either order.

[0053] With the fibrillizable binder chemically and / or thermally activated by either or both of steps 520 and 530, the workflow of Figure 5 may continue with the step of fibrillating the binder in the powder mixture by subjecting the powder mixture to shear forces (step 540). For example, the powder mixture may be blended in a conventional kitchen blender or an industrial blender. Sufficient shear forces to deform (e.g., stretch) the fibrillizable binder and result in a viscous, more pliable mixture may be achieved by blending the powder mixture in the blender at approximately 10,000 RPM for 1-10 minutes (e.g., 5 minutes), or by a subsequent mixing process using a commercial dough mixer or an industrial-sized mortar and pestle. Preferably, a high-shear mixer, such as a high-shear granulator (e.g., a jet mill), may be used. If a solvent is added in solvent activation step 520 to chemically activate the binder, the solvent may optionally be infused into the powder mixture while the powder mixture is subjected to shear forces in step 540. Steps 520 and 540 may then be performed in a single step.

[0054] After the mixture is subjected to shear force, the workflow of FIG. 5 can continue with step 550, which involves pressing the mixture to produce a free-standing film that functions as the electrode film 110, 210, 230. This can be done, for example, using a roller press or calender at a temperature of 150°C and a roll gap of 20 μm. The resulting free-standing electrode film 110, 210, 230 can comprise at least one type of electrode active material, at least one type of fibrillizable binder, and at least one type of dry electrolyte powder in an amount of 5 to 30% by weight of the free-standing electrode film. If the electrode film 110, 210, 230 is laminated onto a current collector before coating with dry electrolyte powder 119 to form the solid electrolyte layer 120, 220 (steps 320, 430), the workflow of FIG. 5 can conclude with the step of laminating the free-standing electrode film 110, 210, 230 onto the current collector (step 560). For example, as explained above, this may be particularly advantageous when producing electrode block 100 for a multilayer battery according to the workflow of Figure 3 (i.e., when Figure 5 is a sub-workflow of step 310). If no current collector is used, or if a current collector is added later (as is the case with optional steps 460 and 470 of Figure 4), step 560 may be omitted.

[0055] As noted above, the workflow of Figure 5 can be advantageously used to produce the electrode films 110, 210, 230 shown in Figures 1 and 2, which can then be assembled into the electrode block 100 of a multi-layer solid-state battery according to the workflow of Figure 3, or into the single-layer solid-state battery 200 according to the workflow of Figure 4. To this end, the powder mixture prepared in step 510 of Figure 5 preferably includes at least some dry electrolyte powder, as noted above, making the activated dry process described herein uniquely suitable for the manufacture of solid-state batteries. By manufacturing the electrode block 100 or solid-state battery 200 in this manner by an entirely dry method from start to finish using a combination of the workflow of Figure 5 with that of Figure 3 or Figure 4, the long drying times and reduced battery performance associated with conventional wet methods can be entirely avoided, resulting in more practical and efficient solid-state battery manufacturing.

[0056] FIG. 6 is a workflow for producing an electrolyte membrane. The workflow of FIG. 6 can be part of an alternative method for dry solid-state battery production. Unlike the solid electrolyte layers 120, 220 described with respect to FIGS. 1-4 , which are formed from dry electrolyte powder 119 coated directly onto electrode membranes 110, 210, the solid electrolyte layer produced in FIG. 6 is in the form of a free-standing membrane that can then be laminated onto an electrode membrane. In this regard, it should be noted that the electrode membrane receiving the electrolyte membrane of FIG. 6 can still be produced according to the dry method of FIG. 5 , thereby resulting in another entirely dry process for producing solid-state batteries.

[0057] The workflow of FIG. 6 can be considered similar to a dry process for producing an electrode film (such as the exemplary process of FIG. 5 ), with the primary difference being that the powder mixture contains ingredients for producing a solid electrolyte rather than a cathode or anode. In particular, the workflow of FIG. 6 can begin with preparing a powder mixture for the electrolyte film (step 610). In this case, the dry electrolyte powder (rather than the electrode active material) can constitute the majority of the powder mixture by weight, e.g., 80% or more by weight of the powder mixture, e.g., 80-97% by weight or 80-99% by weight, preferably 95-99% by weight. Examples of dry electrolyte powders can include any of the materials listed above for the dry electrode powder 119. To form an electrolyte membrane by a dry method (thus avoiding the long drying times associated with conventional wet methods), the powder mixture can further include at least one type of fibrillizable binder, such as PTFE, PVP, PVDF, PEO, or CMC, including composite binders such as those described in U.S. Patent Application No. 17 / 097,200, entitled "Dry Electrode Manufacture with Composite Binder," incorporated by reference above. The use of one or more fibrillizable binders, which can be further chemically or thermally activated to increase their flexibility as described above, can allow the powder mixture to be pressed into a free-standing membrane without breakage and without excessive use of solvents such as NMP.

[0058] Just as with the powder mixtures for the electrode films 110, 210, and 230, it is contemplated that the powder mixture containing the dry electrolyte powder can be lubricated by mixing it in a polymer-containing additive solution before adding the binder. For example, the powder mixture can include an additive solution containing a polymer additive and a liquid carrier in addition to the dry electrolyte powder (and in addition to the subsequently added fibrillizable binder). The additive solution can be less than 5% by weight of the powder mixture, so that the powder mixture can remain a dry powder despite the relatively small amount of liquid added. For example, the final powder mixture containing the dry electrolyte powder, fibrillizable binder, and additive solution can have a total solids content of more than 95% by weight. The polymer additive can be the same as described above. Note that the conductive pastes described above are generally not used when preparing powder mixtures for electrolyte membranes because conductivity is typically undesirable in solid electrolytes.

[0059] Once a powder mixture containing dry electrolyte powder, an optional additive solution for lubricating the dry electrolyte powder, and a fibrillizable binder has been prepared, the workflow of FIG. 6 can continue with activating the fibrillizable binder by one or more activation methods. That is, the workflow of FIG. 6 can include a solvent activation step 620, the same as solvent activation step 520 of FIG. 5, and / or a temperature activation step 630, the same as temperature activation step 530 of FIG. 5. In this manner, the fibrillizable binder can be chemically and / or thermally activated, thereby softening it and allowing it to stretch longer and thinner without breaking, thereby improving its adhesive strength. If both solvent activation step 620 and temperature activation step 630 are used, the two steps can proceed in either order. The workflow of FIG. 6 can continue with fibrillizing the binder in the powder mixture by subjecting the powder mixture to shear forces (step 640), which can be the same as step 540 of FIG. 5. If a solvent is added in solvent activation step 620 to chemically activate the binder, the solvent may optionally be infused into the powder mixture while the powder mixture is subjected to shear forces in step 640. Steps 620 and 640 may then be performed in a single step.

[0060] After the mixture is subjected to shear force, the workflow of FIG. 6 can end with step 650, which presses the mixture to produce a free-standing membrane. This can be performed, for example, in the same manner as step 550 of FIG. 5. The resulting free-standing electrolyte membrane can comprise at least one type of fibrillizable binder and at least one type of dry electrolyte powder, which constitutes a majority of the free-standing electrolyte membrane by weight, e.g., in an amount of 80% by weight or more of the free-standing electrolyte membrane, e.g., 80-97% by weight or 80-99% by weight, preferably 95-99% by weight. Such a free-standing electrolyte membrane can then be laminated onto an electrode membrane (either a cathode or anode) to produce a solid-state battery or its intermediate product (e.g., an electrode block for a multilayer solid-state battery). Similar to the workflows of FIGS. 3 and 4, the workflow of FIG. 6 can be used in combination with the workflow of FIG. 5 to produce a solid electrode block or solid-state battery by an entirely dry process from start to finish. In this way, the long drying times and reduced battery performance associated with conventional wet processes can likewise be completely avoided, resulting in more practical and efficient solid-state battery manufacturing.

[0061] The above description is provided by way of example and not by way of limitation. In view of the above disclosure, those skilled in the art will be able to devise variations that fall within the spirit and scope of the invention disclosed herein. Furthermore, the various features of the embodiments disclosed herein can be used alone or in various combinations with each other and are not intended to be limited to the specific combinations described herein. Accordingly, the scope of the claims is not limited by the exemplified embodiments.

Claims

1. 1. A method for manufacturing an electrode block for a solid-state battery, the method comprising: providing an electrode film having a current collector on a first surface of the electrode film; coating a layer of dry electrolyte powder on a second surface of the electrode film opposite the first surface; and pressing the dry electrolyte powder coated on the electrode film to form a solid electrolyte layer on the electrode film; Equipped with The step of providing the electrode film having the current collector comprises: preparing a powder mixture comprising at least one type of electrode active material and at least one type of fibrillizable binder; fibrillating the at least one type of fibrillizable binder in the powder mixture by subjecting the powder mixture to a shear force; pressing the powder mixture into a free-standing film; and laminating the free-standing film on the current collector; and and further comprising adding a solvent to the powder mixture to activate the at least one type of fibrillizable binder prior to the fibrillating step. method.

2. The method of claim 1 , wherein the powder mixture further comprises at least one type of dry electrolyte powder.

3. 1. A method of manufacturing a solid state battery, the method comprising: providing a first electrode film having a first surface and a second surface opposite the first surface; providing a second electrode film having a first surface and a second surface opposite the first surface; laminating the first electrode film onto a first current collector with the first current collector on the first surface of the first electrode film; coating the second surface of the first electrode film with a layer of dry electrolyte powder; disposing the second surface of the second electrode film on the layer of dry electrolyte powder; and pressing the first electrode film with the layer of dry electrolyte powder coated thereon together with the second electrode film to produce a solid-state battery comprising the first electrode film, the second electrode film, and a solid electrolyte layer therebetween. Equipped with The steps of providing the first electrode film and / or providing the second electrode film may include: preparing a powder mixture comprising at least one type of electrode active material and at least one type of fibrillizable binder; fibrillating the at least one type of fibrillizable binder in the powder mixture by subjecting the powder mixture to a shear force; and pressing the powder mixture into a free-standing film. and and further comprising adding a solvent to the powder mixture to activate the at least one type of fibrillizable binder prior to the fibrillating step. method.

4. The method of claim 3 , wherein the powder mixture further comprises at least one type of dry electrolyte powder.

5. laminating the second electrode film onto a second current collector with the second current collector on the first surface of the second electrode film. The method of claim 3 or 4, further comprising:

6. The method of claim 5 , wherein the steps of depositing the first electrode film and depositing the second electrode film are performed before the step of coating.

7. The method of claim 5 , wherein the steps of laminating the first electrode film and laminating the second electrode film are performed after the step of pressing.

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