Bipolar electrode for secondary metal ion battery cell

Abstract

Aspects of the present disclosure include bipolar electrode designs for secondary metal ion battery cells and methods of making the same. An example vehicle includes an electric motor and a battery pack electrically connected to the electric motor. The battery pack includes a battery cell including a bipolar current collector, an anode coating layer formed on a first surface of the bipolar current collector, and a cathode coating layer formed on a second surface of the bipolar current collector. The battery cell also includes a roll-to-roll ion channel blocker positioned along a first edge of the bipolar current collector and a piece-by-piece ion channel blocker positioned along a second edge and a third edge of the bipolar current collector orthogonal to the first edge. The battery cell also includes an ion conductive gel electrolyte formed on the anode coating and the cathode coating.

Description

Technical Field

[0001] The present disclosure relates to battery cell manufacturing, and more particularly to bipolar electrode designs for secondary metal-ion battery cells. Background Art

[0002] Electrodes are widely used in a range of devices that store electrical energy, including primary (non-rechargeable) battery cells, secondary (rechargeable) battery cells, fuel cells, and capacitors. An ideal electrode needs to balance various energy storage properties, such as energy density, power density, maximum charge rate, internal leakage current, equivalent series resistance (ESR), charge-discharge cycle durability, high conductivity, and low tortuosity. Electrodes often include current collectors to supplement or improve these energy storage properties. Current collectors can be added to provide higher specific conductance and can increase the available contact area to minimize the interfacial contact resistance between the electrode and its terminals.

[0003] A current collector is typically a sheet of conductive material to which an active electrode material is attached. Aluminum foil, stainless steel, copper, and titanium foil are commonly used as current collectors for electrodes. For example, in some electrode manufacturing processes, a film comprising activated carbon powder (i.e., active electrode material) is attached to a thin aluminum foil using a binding material or using an adhesive layer. In order to improve the interfacial bonding quality between the active electrode material film and the current collector, the combination of the film and the current collector is processed in a pressure laminator, such as a calendering process or roller pressing. This process is commonly referred to as calendering. Therefore, the manufacture of an electrode typically includes the production of an active electrode material film (including, for example, cathode and / or anode slurry preparation, incorporation of any conductive additives and binding materials, deposition of the slurry with a limited loading amount, and drying) and lamination of the film onto the current collector. Summary of the Invention

[0004] In one exemplary embodiment, a vehicle includes an electric motor and a battery pack electrically coupled to the electric motor. The battery pack includes a battery cell, the battery cell including a bipolar current collector, an anode coating formed on a first surface of the bipolar current collector, and a cathode coating formed on a second surface of the bipolar current collector. The battery cell also includes a roll-to-roll ion channel blocker positioned along a first edge of the bipolar current collector and a sheet-by-sheet ion channel blocker positioned along a second edge and a third edge of the bipolar current collector orthogonal to the first edge. The battery cell also includes an ionically conductive gel electrolyte formed on the anode coating and the cathode coating.

[0005] In addition to one or more features described herein, in some embodiments, the roll-to-roll ion channel blocker and the sheet-by-sheet ion channel blocker comprise a metal ion channel blocker. In some embodiments, the metal ion channel blocker comprises a non-ion conductive gel having infinite viscosity at zero shear rate.

[0006] In some embodiments, the non-ionically conductive gel is formed in situ from a viscous solution comprising an organic solvent and a gelling polymer mixture comprising a cross-linkable polymer, a rheology modifier, and a cross-linking initiator.

[0007] In some embodiments, the metal ion channel blocker is formed in situ and comprises a polyimide or a polyimide blended with a polyvinylidene fluoride (PVdF) polymer.

[0008] In some embodiments, the ion-conductive gel electrolyte is formed from a liquid electrolyte precursor including an organic solvent, a metal ion salt, a cross-linkable polymer, and a cross-linking initiator.

[0009] In some embodiments, the ionically conductive gel electrolyte is filled onto the battery cell to a fill level between the uppermost surface of the anode coating and the uppermost surface of the cathode coating.

[0010] In another exemplary embodiment, a battery cell includes a bipolar current collector, an anode coating formed on a first surface of the bipolar current collector, and a cathode coating formed on a second surface of the bipolar current collector. The battery cell also includes a first ion channel blocker positioned along a first edge of the bipolar current collector, a second ion channel blocker positioned along a second edge of the bipolar current collector, and a third ion channel blocker positioned along a third edge of the bipolar current collector, the second edge and the third edge being orthogonal to the first edge of the bipolar current collector. The battery cell also includes an ion-conductive gel electrolyte formed on the anode coating and the cathode coating.

[0011] In some embodiments, the metal ion channel blocker comprises a non-ion conductive gel having infinite viscosity at zero shear rate.

[0012] In some embodiments, the non-ionically conductive gel is formed from a viscous solution comprising an organic solvent and a gelling polymer mixture comprising a cross-linkable polymer, a rheology modifier, and a cross-linking initiator.

[0013] In some embodiments, the organic solvent includes a non-flammable organic solvent, such as triethyl phosphate.

[0014] In some embodiments, the metal ion channel blocker is formed in situ and comprises a polyimide or a polyimide blended with a polyvinylidene fluoride (PVdF) polymer.

[0015] In some embodiments, the ion-conductive gel electrolyte is formed from a liquid electrolyte precursor including an organic solvent, a metal ion salt, a cross-linkable polymer, and a cross-linking initiator.

[0016] In some embodiments, the ionically conductive gel electrolyte is filled onto the battery cell to a fill level between the uppermost surface of the anode coating and the uppermost surface of the cathode coating.

[0017] In yet another exemplary embodiment, a method may include providing a bipolar current collector, forming an anode coating on a first surface of the bipolar current collector, forming a cathode coating on a second surface of the bipolar current collector opposite the first surface of the bipolar current collector, positioning a roll-to-roll ion channel blocker along a first edge of the bipolar current collector, positioning a sheet-by-sheet ion channel blocker along second and third edges of the bipolar current collector orthogonal to the first edge, and forming an ion conductive gel electrolyte on the anode coating and the cathode coating.

[0018] In some embodiments, the metal ion channel blocker comprises a non-ion conductive gel having infinite viscosity at zero shear rate.

[0019] In some embodiments, the non-ionically conductive gel is formed from a viscous solution comprising an organic solvent and a gelling polymer mixture comprising a cross-linkable polymer, a rheology modifier, and a cross-linking initiator.

[0020] In some embodiments, the organic solvent includes a non-flammable organic solvent, such as triethyl phosphate.

[0021] In some embodiments, the metal ion channel blocker is formed in situ and comprises a polyimide or a polyimide blended with a PVdF polymer.

[0022] In some embodiments, the ion-conductive gel electrolyte is formed from a liquid electrolyte precursor including an organic solvent, a metal ion salt, a cross-linkable polymer, and a cross-linking initiator.

[0023] In some embodiments, the ionically conductive gel electrolyte is filled onto the battery cell to a fill level between the uppermost surface of the anode coating and the uppermost surface of the cathode coating.

[0024] The above features and advantages and other features and advantages of the present disclosure will become apparent when the following detailed description is read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Additional features, advantages, and details appear, by way of example only, in the following detailed description, which refers to the accompanying drawings.

[0026] Figure 1 is a vehicle configured according to one or more embodiments;

[0027] Figure 2A is an example battery cell according to one or more embodiments;

[0028] Figure 2B According to one or more embodiments Figure 2A a detailed view of the battery cell shown;

[0029] Figure 2C According to one or more embodiments Figure 2B A cross-sectional view of the battery cell taken along line XX';

[0030] Figure 3 is an example view of an electrode of a battery cell during a first portion of a roll-to-roll manufacturing process according to one or more embodiments;

[0031] Figure 4 is an example view of an electrode of a battery cell during a second portion of a roll-to-roll manufacturing process according to one or more embodiments;

[0032] Figure 5 is an example view of electrodes of a battery cell during a third portion of a roll-to-roll manufacturing process according to one or more embodiments; and

[0033] Figure 6 is a flow chart according to one or more embodiments. DETAILED DESCRIPTION

[0034] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate the same or corresponding parts and features.

[0035] Electrodes typically include current collectors to supplement or improve the electrical energy storage characteristics of the final integrated device (e.g., a battery). The current collector typically comprises a sheet of conductive material (e.g., aluminum foil) to which the active electrode material is attached. An energy storage system, such as a battery cell or battery pouch, may comprise a plurality of stacked anode and cathode current collectors, active materials dispersed or located on the current collectors, and a sufficient number of separators to prevent short circuits between the anode and cathode current collectors. Thus, in many electrode configurations, there is a clear separation between the anode and cathode, each electrode having a specific function, and electrons flow from the anode to the cathode through an external circuit.

[0036] As demand for energy storage systems that offer higher energy density, faster charging, and longer operating life increases—driven in part by the surge in electric vehicles—materials used in battery cell components face significant challenges. Research and development efforts continue to identify new materials and manufacturing technologies that can meet the growing demands on battery cells and other energy storage systems.

[0037] Compared to traditional monopolar electrodes, bipolar electrodes have the unique property of acting as both anode and cathode within the same battery cell. This dual functionality eliminates the need for separate anode and cathode structures and simplifies the overall battery architecture. In a bipolar electrode, the portion of the bipolar electrode that functions as the anode contains the anode active material, which undergoes electrochemical reactions during the discharge phase. The other side of the bipolar electrode acts as the cathode and contains the cathode active material, which undergoes electrochemical reactions during the charge phase.

[0038] Bipolar electrode designs offer several advantages over monopolar electrodes, including increased energy density (e.g., approaching 250 Wh / kg and exceeding 500 Wh / L with LFP-graphite cells), reduced mass of non-cell stack components (meaning relatively lower current for delivering the same power), and less heat generation (meaning less cooling capacity is required, e.g., improved DCFCs).

[0039] However, challenges remain in designing and manufacturing bipolar electrodes. Typically, bipolar electrode designs require solid electrolytes that are usually manufactured ex situ (increasing costs and integration complexity), which means that the bipolar electrodes themselves are typically limited to batch ex situ manufacturing processes. In addition, the bipolar electrodes themselves are limited by the relatively high interfacial resistance between the electrodes and the solid electrolyte (compared to monopolar designs). To alleviate these limitations, liquid electrolytes can be introduced to minimize the interfacial resistance between the electrodes and the solid electrolyte. Unfortunately, the additional bill of materials (BOM) required to support this process (e.g., the liquid electrolyte itself, blockers to prevent liquid electrolyte leakage, etc.) increases the complexity of bipolar electrode manufacturing and introduces new design limitations (e.g., liquid electrolyte leakage, thin frame components in each bipolar electrode sheet, etc.). Notably, this requires additional current collectors to offset the weight and / or volumetric energy density gains. In particular, assuming that the single-sided coated cathode and anode electrodes contain a separator and electrolyte in the middle, the periphery of existing bipolar electrodes using liquid electrolytes needs to be wrapped.

[0040] The present disclosure introduces a new bipolar electrode and electrode assembly design and its manufacturing method for secondary metal ion battery cells. Utilize the continuous in-situ formation of metal ion channel blockers on the edge of the cathode electrode coating, rather than relying on batch non-in-situ manufacturing processes and complex BOM integration, to provide a continuous bipolar electrode manufacturing process with streamlined low-cost materials. In some embodiments, the ion channel blocker is applied to at least one side edge of the cathode active coating by roll-to-roll and piece-by-piece in a continuous roll-to-roll manufacturing process. The ion channel blocker can be roll-to-roll and piece-by-piece formed by distributing a viscous solution comprising an organic solvent, a cross-linkable polymer, a rheology modifier and a cross-linking initiator (e.g., a UV cross-linking initiator). The solution can have a modifier to provide self-leveling properties, and subsequent heat and / or UV exposure can convert the solution into a non-ionic conductive gel-type ion channel blocker (i.e., a non-ionic conductive gel) with infinite viscosity at zero shear rate. After completing the bipolar electrode stack, the stack is wetted using a liquid electrolyte comprising an organic solvent (e.g., a carbonate solvent, an ether-based solvent, etc.), a metal ion salt, a cross-linkable polymer and a cross-linking initiator. Cross-linking can be initiated in a similar manner to non-ionically conductive gels, except that the result is the formation of an ionically conductive gel electrolyte.

[0041] According to one or more embodiments, the use of continuous in-situ metal ion channel blockers on the edge of the cathode electrode coating provides several technical advantages over existing electrode manufacturing technologies. Notably, the manufacturing process described herein can be used to continuously produce bipolar electrodes without increasing the interfacial resistance between the electrolytes, which is in part due to the conversion of liquid non-ionic electrolytes through gelation. In addition, the bipolar electrode design and manufacturing process described herein is not limited to lithium chemistry and can be easily applied to sodium (Na) ion battery cell design to reduce the cost of Na ion battery cells, for example.

[0042] According to an exemplary embodiment, the vehicle Figure 1 100. Vehicle 100 is shown in the form of an automobile having a body 102. Body 102 includes a passenger compartment 104 within which a steering wheel, front seats, and rear passenger seats (not separately shown) are located. Within body 102 are various components, including, for example, an electric motor 106 (shown as a projection beneath the front hood). Electric motor 106 is shown for ease of illustration and discussion only. It should be understood that the configuration, location, size, arrangement, etc. of electric motor 106 are not intended to be particularly limited, and that all such configurations (including multi-motor configurations) are contemplated within the present disclosure.

[0043] The electric motor 106 is powered by a battery pack 108 (shown as a projection near the rear of the vehicle 100). The battery pack 108 is shown for ease of illustration and discussion only. It should be understood that the configuration, location, size, arrangement, etc. of the battery pack 108 are not meant to be particularly limited, and all such configurations (including separate configurations) are within the intended scope of the present disclosure. Furthermore, while the present disclosure is primarily discussed in the context of a battery pack 108 configured for use with the electric motor 106 of the vehicle 100, the aspects described herein may similarly be incorporated into any system (vehicle, building, etc.) having an energy storage system (e.g., one or more battery packs or modules), and all such configurations and applications are within the intended scope of the present disclosure.

[0044] As will be described in detail herein, battery pack 108 includes one or more battery cells and / or battery pouches having a novel bipolar electrode design that includes ion channel blockers applied roll-to-roll and sheet-by-sheet to corresponding cathode active coatings. Figure 2B An example electrode stack is shown in . Figure 3-5 Shown are example views of bipolar electrodes during an example roll-to-roll manufacturing process.

[0045] Figure 2A An example battery cell 202 is shown according to one or more embodiments. The battery cell 202 may be used as a battery pack (e.g. Figure 1 One of the multiple battery cells in the battery pack 108) is combined. Figure 2B shows a method according to one or more embodiments Figure 2A A detailed view 204 of battery cell 202 is shown. Figure 2C shows a method according to one or more embodiments Figure 2B 2 is a cross-sectional view of the battery cell 202 taken along line XX′.

[0046] like Figure 2B and 2C As shown, the battery cell 202 includes one or more stacked bipolar current collectors 206 (also referred to as shared current collectors). Although only one bipolar current collector 206 is shown for simplicity, it should be readily understood that the battery cell 202 may include any number of bipolar current collectors (e.g., 2, 4, 10, 20, 100, etc.), and all such configurations are within the intended scope of the present disclosure. The bipolar current collector 206 includes an anode coating 208 and a cathode coating 210 (collectively defining, for example, any number of coated bipolar current collectors 212). The anode coating 208 and the cathode coating 210 may be formed on opposing surfaces of the bipolar current collector 206.

[0047] Bipolar current collector 206 can be made of a sheet or foil of any suitable conductive material for bipolar applications, such as stainless steel with a passive film formed on its surface. The passive film on stainless steel can be composed of a chromium (Cr) oxide layer on the so-called metal substrate side (the surface facing the inside of the battery) and a hydroxide layer including iron (Fe) and Cr on the atmosphere side (the surface facing the outside). In some embodiments, the anode surface / side (e.g., graphite coated side) of bipolar current collector 206 includes nickel plating to improve electrochemical stability. In other words, bipolar current collector 206 can include stainless steel with a nickel coating on one surface. Each layer thickness can be about 1 to 3 nm, although other thicknesses are also within the expected range of the present disclosure. Without wishing to be bound by theory, it is understood that, in normal environments, the higher the Cr content (e.g., Cr / (Cr+Fe) ratio) in the passive film, the higher the corrosion resistance, thereby reducing the elution of metal ions.

[0048] The anode coating 208 and the cathode coating 210 may include various cathode or anode active materials, respectively, such as activated carbon powder, nickel manganese cobalt oxide (NMC), lithium iron phosphate (LFP), nickel cobalt aluminum oxide (NCA), nickel cobalt manganese aluminum oxide (NCMA), lithium iron phosphate (LMFP), lithium rich manganese (LMR), lithium manganese oxide (LMO), graphite, silicon, silicon-graphite composites, tin, tin oxide (SnO2), lithium titanate (Li4Ti5O 12 In some embodiments, for example, for sodium ion battery (SIB) applications, the cathode or anode active materials may include SIB active materials such as layered and tunnel structured transition metal oxides, polyanionic compounds and Prussian blue analogs (PBA), hard carbon materials such as petroleum coke or mesophase carbon microbeads (MCMB), graphite, sodium titanate such as Na2Ti3O7 and Na 0.44 MnO2, tin-based compounds such as SnO2 and SnS2, phosphorus-based compounds such as phosphorus-carbon composites or phosphorus-based alloys, and combinations thereof.

[0049] The battery cell 202 also includes a roll-to-roll ion channel blocker 214, a sheet-by-sheet ion channel blocker 216, and an ion-conductive gel electrolyte 218, configured and arranged as shown. Figure 3-5 The fabrication and placement of the roll-to-roll ion channel blocker 214, the sheet-by-sheet ion channel blocker 216, and the ion-conductive gel electrolyte 218 are discussed in greater detail.

[0050] The battery cell 202 may also include one or more separators 220. The separators 220 may be positioned to separate each of the one or more coated bipolar current collectors 212. Note that for clarity, Figure 2BThe separator 220 is omitted from the illustrated view. The separator 212 may include a dielectric material such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and composites thereof, although other dielectrics are also contemplated within the scope of the present disclosure. In some embodiments, the separator 212 may include a thermally stable coating to improve shrinkage behavior (e.g., a porous ceramic coating or a porous ester-type polymer coating, including, for example, polyimide, polyamide, polyimide-polyamide (PI / PA) copolymers, etc.).

[0051] Figure 3 A battery cell (e.g., a cell) is shown during a first portion (not separately shown) of a roll-to-roll manufacturing process according to one or more embodiments. Figure 2A 、 2B , and 2C battery cells 202). In some embodiments, the electrode 300 includes a bipolar current collector 206. In some embodiments, an anode coating 208 is formed on a first surface 302 of the bipolar current collector 206 (shown only by projection). In some embodiments, the anode coating 208 is formed continuously during a roll-to-roll manufacturing process. In some embodiments, a cathode coating 210 is formed on a second surface 304 opposite the first surface 302 of the bipolar current collector 206. In some embodiments, multiple cathode coatings 210 are formed intermittently during a roll-to-roll manufacturing process. In some embodiments, the electrode 300 is guided along the roll-to-roll manufacturing process in a direction 306 (indicated by a stylized arrow pointing from north to south relative to the orientation shown) via one or more rollers (e.g., pulling rollers, positioning rollers, etc., not separately shown).

[0052] Figure 4 An example view of an electrode 300 during a second portion (not separately shown) of a roll-to-roll manufacturing process according to one or more embodiments is shown. In some embodiments, a roll-to-roll ion channel blocker 214 is dispensed onto a second surface 304 of the bipolar current collector 206 at a first edge 402 (also referred to as a first cathode electrode coating edge) of the bipolar current collector 206. In some embodiments, the roll-to-roll ion channel blocker 214 is continuously dispensed as the electrode 300 is pulled or otherwise passed along the direction 306. In some embodiments, the first edge 402 is formed parallel to the direction 306. In some embodiments, the roll-to-roll ion channel blocker 214 is a metal ion channel blocker.

[0053] The roll-to-roll ion channel blocker 214 can be formed from a viscous solution dispensed onto the first edge 402 of the bipolar current collector 206. In some embodiments, the viscous solution can include an organic solvent and a gelling polymer mixture comprising a cross-linkable polymer, a rheology modifier, and a cross-linking initiator. The viscous solution can be polymerized using, for example, UV exposure and / or heat, which initiates cross-linking of the cross-linkable polymer. The result is a phase transition from an initial liquid form to a gel form having infinite viscosity at zero shear rate.

[0054] Alternatively or in addition, the roll-to-roll ion channel blocker 214 can be formed in situ and can include a polyimide or a polyimide blended with a polymer (e.g., a polyvinylidene fluoride polymer) dispensed on the first edge 402 of the bipolar current collector 206. In some embodiments, the fully imidized polyamide-polymer blend is dried using, for example, a heater (infrared heater, in-line oven, air heater, etc.) and / or a dedicated ventilation system for solvent recovery (not separately shown). In some embodiments, such as those using a fully imidized polyimide solution as the channel blocker, the polyimide can be applied in a dissolved form in a processing solvent (e.g., NMP).

[0055] like Figure 4 As further shown, in some embodiments, a sheet-by-sheet ion channel blocker 216 is dispensed onto the second surface 304 of the bipolar current collector 206. In some embodiments, the sheet-by-sheet ion channel blocker 216 is dispensed onto the second edge 404 and the third edge 406 opposite the second edge 404. In some embodiments, the second edge 404 and the third edge 406 are orthogonal to the first edge 402 and the direction 306 (as shown). In some embodiments, the sheet-by-sheet ion channel blocker 216 is dispensed intermittently as the electrode 300 is pulled or otherwise passed along the direction 306. In some embodiments, the sheet-by-sheet ion channel blocker 216 is dispensed from the first edge 402 and along the corresponding second edge 404 or third edge 406. In some embodiments, the sheet-by-sheet ion channel blocker 216 is positioned to cover the underlying anode coating 208 (as shown). In some embodiments, the sheet-by-sheet ion channel blocker 216 is a metal ion channel blocker. The sheet-by-sheet ion channel blocker 216 can be made of similar materials and formed in a manner similar to that described above with respect to the roll-to-roll ion channel blocker 214.

[0056] In some embodiments, after forming the roll-to-roll ion channel blocker 214 and the sheet-by-sheet ion channel blocker 216, the electrode 300 is trimmed for packaging. In some embodiments, the electrode 300 is cut along the cut line CL to separate discrete portions of the cathode coating 210. In some embodiments, the trimming includes defining tabs 408 (also referred to as notching) for the bipolar current collector 206. In some embodiments, the tabs 408 (not separately shown) are formed only for the topmost and / or bottommost bipolar current collectors 206 in a stack of multiple electrodes 300.

[0057] Figure 5 An example view of an electrode 300 is shown during a third portion (not separately shown) of a roll-to-roll manufacturing process according to one or more embodiments. Figure 5 As shown, an ion-conductive gel electrolyte 502 is formed on the electrode 300. In some embodiments, the ion-conductive gel electrolyte 502 is formed by wetting the electrode 300 with a liquid electrolyte precursor (not separately shown). Although not intended to be particularly limiting, the liquid electrolyte precursor may include, for example, a fluorinated phosphate flame retardant electrolyte, dimethyl methylphosphonate (DMMP), trimethyl phosphate (TMP), triethyl phosphate (TEP), tris(2,2,2-trifluoroethyl)phosphate (TFEP), and combinations thereof, and may or may not include additives such as 1-diphenylphosphoryloxy-4-methylbenzene (DPMB) (e.g., at 2 wt %).

[0058] In some embodiments, the liquid electrolyte precursor includes an organic solvent, a metal ion salt, a cross-linkable polymer, and a cross-linking initiator. In some embodiments, the liquid electrolyte precursor includes a phosphonate functionalized ionic liquid (PFIL) as a multifunctional additive to the base liquid electrolyte precursor mixture, and the base liquid electrolyte precursor mixture includes ethylene carbonate, dimethyl carbonate, and lithium hexafluorophosphate (LiPF6). It is worth noting that the addition of 5 wt% PFIL has been shown to improve cycle stability and rate. In some embodiments, for stability, the liquid electrolyte precursor includes TEP and / or other phosphate-based organic solvents.

[0059] In some embodiments, the organic solvent includes ethylene carbonate (EC) and / or dimethyl carbonate (DMC). In some embodiments, the organic solvent includes ethylene carbonate (EC). EC is a cyclic carbonate solvent that can be used in lithium-ion batteries. It has good solubility for lithium salts and helps to form a stable solid electrolyte interface (SEI) layer on the electrode surface. In some embodiments, the organic solvent includes dimethyl carbonate (DMC). DMC is another cyclic carbonate solvent. It has a high dielectric constant and good solubility for lithium salts. DMC can be used in combination with other solvents to optimize electrolyte performance. In some embodiments, the organic solvent includes diethyl carbonate (DEC). DEC is a cyclic carbonate solvent similar to DMC. It can be used in combination with other solvents to improve the overall performance of the electrolyte. In some embodiments, the organic solvent includes ethyl methyl carbonate (EMC). EMC is a linear carbonate solvent that can be used in lithium-ion battery electrolytes. It can improve the low-temperature performance of the battery.

[0060] In some embodiments, the metal ion salt includes a lithium salt, such as LiPF6. Other salts are also possible. In some embodiments, the metal ion salt includes lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). In some embodiments, the metal ion salt includes lithium perchlorate (LiClO4). In some embodiments, the metal ion salt includes lithium trifluoromethanesulfonate (LiCF3SO3). In some embodiments, the metal ion salt includes lithium borofluoride (LiBF4). In some embodiments, the metal ion salt includes lithium bis(oxalate)borate (LiBOB). In some embodiments, the metal ion salt includes lithium bis(fluorosulfonyl)imide (LiFSI).

[0061] In some embodiments, the crosslinkable polymer includes, for example, polyethylene oxide (PEO) having terminal acrylate groups, acrylates, etc. In some embodiments, the crosslinking initiator includes, for example, ultraviolet (UV) light and / or heat and / or a chemical initiator. Such initiators may include benzoin methyl ether, acrylate functionalized polymers, benzophenone (CAS No. 119-61-9), 2-hydroxy-2-methyl-1-phenylpropanone (CAS No. 7473-98-5), etc. Thermal initiators include bis (4-tert-butylcyclohexyl) peroxydicarbonate (CAS No. 15520-11-3), tert-hexyl peroxy-2-ethylhexanoate (CAS No. 137791-98-1), etc.

[0062] In some embodiments, the liquid electrolyte precursor is filled to a filling level FL between the highest surface 504 of the anode coating 208 and the highest surface 506 of the cathode coating 210. In other words, the liquid electrolyte precursor hangs above the cathode coating 210 but does not completely cover the anode coating 208. This also results in the liquid electrolyte precursor filling level FL being lower than that of the sheet-by-sheet ion channel blocker 216 (see Figure 4 In some embodiments, after filling (and after any soaking time as desired), crosslinking can be initiated (e.g., UV exposure, heat exposure, etc.) in a manner similar to the aforementioned non-ionically conductive gels, except that the result is the formation of an ionically conductive gel electrolyte 502.

[0063] There are at least two possible fabrication schemes for combining the formation of the ionically conductive gel electrolyte 502 with the roll-to-roll fabrication of the electrode 300. Each fabrication scheme will be described in turn.

[0064] In some embodiments, multiple intermediate bipolar electrodes (each a cutout of electrode 300, see Figure 4 ) are assembled into bipolar stacks (not shown separately) with separators made of polyolefins (PE, PP, etc.) and / or ceramics using a Z-folding method and / or a simple sheet stacking method. The bipolar stack can be packaged into polymer laminate bags (also called laminated polymer packaging).

[0065] The polymer laminate bag can be completely wetted using a liquid electrolyte precursor as described above. In some embodiments, the liquid electrolyte precursor can be poured into the polymer laminate bag, allowed to soak the polymer laminate bag (for any desired soaking duration), the polymer laminate bag can be sealed, and the polymer laminate bag can be heated to induce crosslinking. In some embodiments, the polymer laminate bag can be heated to a temperature of 60 degrees Celsius to convert the liquid electrolyte precursor into an ionically conductive gel electrolyte 502.

[0066] Alternatively, in some embodiments, multiple intermediate bipolar electrodes (each a cutout of electrode 300, see Figure 4) is assembled into a bipolar stack (not shown separately) having a separator made of polyolefin (PE, PP, etc.) and / or ceramic using a Z-folding method and / or a simple sheet stacking method. In some embodiments, a predetermined container is coated with a chemically stable polymer (e.g., PP, PE, PTFT, PPS, etc.) and the bipolar stack is placed in the container. In some embodiments, the bipolar stack is compressed and / or the electrodes are pre-welded to maintain the height of the bipolar stack in the container (i.e., to prevent displacement and / or to keep the electrodes aligned). In some embodiments, a liquid electrolyte precursor can be poured into a predetermined container and allowed to soak for any desired soaking duration. The predetermined container can be sealed, and the predetermined container can be heated to induce crosslinking. In some embodiments, the predetermined container can be heated to a temperature of 60 degrees Celsius to convert the liquid electrolyte precursor into an ion conductive gel electrolyte 502. After the ion conductive gel electrolyte 502 is completely gelled, the bipolar stack can be taken out of the predetermined container and the bipolar stack can be trimmed to any desired size. For example, after liquid electrode cross-linking, the bipolar electrode stack can be moved to a trimming station or module where the folded separator and a small amount of anode coating can be trimmed to ensure complete separation of metal ion pathways between the bipolar electrodes.

[0067] Now refer to Figure 6 , a flowchart 600 for manufacturing a bipolar electrode is generally shown according to one embodiment. Figure 1-5 Flowchart 600 is described and may include Figure 6 Although described in a particular order, Figure 6 The blocks described in may be rearranged, subdivided, and / or combined.

[0068] At block 602 , the method includes providing a bipolar current collector.

[0069] At block 604 , the method includes forming an anodic coating on a first surface of a bipolar current collector.

[0070] At block 606, the method includes forming a cathode coating on a second surface of the bipolar current collector. In some embodiments, the second surface of the bipolar current collector is opposite the first surface of the bipolar current collector.

[0071] At block 608, the method includes positioning a roll-to-roll ion channel blocker (also referred to as a first ion channel blocker) along a first edge of the bipolar current collector. At block 610, the method includes positioning a sheet-by-sheet ion channel blocker (also referred to as a second and third ion channel blocker, respectively) along a second edge and a third edge of the bipolar current collector. In some embodiments, the second edge and the third edge of the bipolar current collector are orthogonal to the first edge.

[0072] In some embodiments, the metal ion channel blocker comprises a non-ion conductive gel having infinite viscosity at zero shear rate.

[0073] In some embodiments, the non-ionically conductive gel is formed from a viscous solution comprising an organic solvent and a gelling polymer mixture comprising a cross-linkable polymer, a rheology modifier, and a cross-linking initiator.

[0074] In some embodiments, the organic solvent includes a non-flammable organic solvent, such as triethyl phosphate.

[0075] In some embodiments, the metal ion channel blocker is formed in situ and comprises a polyimide or a polyimide blended with a polyvinylidene fluoride (PVdF) polymer.

[0076] At block 612, the method includes forming an ionically conductive gel electrolyte on the anode coating and the cathode coating. In some embodiments, the ionically conductive gel electrolyte is formed from a liquid electrolyte precursor including an organic solvent, a metal ion salt, a cross-linkable polymer, and a cross-linking initiator.

[0077] In some embodiments, the ionically conductive gel electrolyte is filled onto the battery cell to a fill level between the uppermost surface of the anode coating and the uppermost surface of the cathode coating.

[0078] The terms "a" and "an" do not indicate a limitation of quantity, but rather indicate the presence of at least one of the referenced item. The term "or" means "and / or" unless the context clearly indicates otherwise. References to "an aspect" throughout this specification mean that a particular element (e.g., feature, structure, step, or characteristic) described in conjunction with that aspect is included in at least one aspect described herein and may or may not be present in other aspects. Furthermore, it should be understood that the described elements may be combined in any suitable manner in various aspects.

[0079] When an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.

[0080] Unless otherwise indicated herein, all test standards are the most recent standards in effect as of the filing date of this application or, if priority is claimed, the filing date of the earliest priority application in which the test standards appear.

[0081] Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0082] Although the above disclosure has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope thereof. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope of the present disclosure. Therefore, it is intended that the present disclosure is not limited to the particular embodiments disclosed, but is intended to include all embodiments falling within its scope.

Claims

1. A vehicle comprising: electric motors; and A battery pack electrically coupled to the electric motor, the battery pack including battery cells, the battery cells including: bipolar current collector; forming an anode coating on a first surface of the bipolar current collector; forming a cathode coating on a second surface of the bipolar current collector, the second surface of the bipolar current collector being opposite the first surface of the bipolar current collector; a roll-to-roll ion channel blocker positioned along a first edge of the bipolar current collector; a sheet-by-sheet ion channel blocker positioned along a second edge and a third edge of the bipolar current collector, the second edge and the third edge of the bipolar current collector being orthogonal to the first edge; and An ion-conductive gel electrolyte is formed on the anode coating and the cathode coating.

2. The vehicle according to claim 1, wherein The roll-to-roll ion channel blockers and sheet-by-sheet ion channel blockers include metal ion channel blockers.

3. The vehicle according to claim 2, wherein: The metal ion channel blocker comprises a non-ion conductive gel having infinite viscosity at zero shear rate.

4. The vehicle according to claim 3, wherein: The non-ion conductive gel is formed from a viscous solution comprising an organic solvent and a gelling polymer mixture, wherein the gelling polymer mixture comprises a cross-linkable polymer, a rheology modifier and a cross-linking initiator.

5. The vehicle according to claim 2, wherein: The metal ion channel blocker is formed in situ and comprises polyimide or polyimide blended with polyvinylidene fluoride (PVdF) polymer.

6. The vehicle according to claim 1, wherein The ion-conductive gel electrolyte is formed from a liquid electrolyte precursor including an organic solvent, a metal ion salt, a cross-linkable polymer, and a cross-linking initiator.

7. The vehicle according to claim 1, wherein: The ion-conductive gel electrolyte is filled on the battery cell to a filling level between the uppermost surface of the anode coating and the uppermost surface of the cathode coating.

8. A battery cell comprising: bipolar current collector; forming an anode coating on a first surface of the bipolar current collector; forming a cathode coating on a second surface of the bipolar current collector, the second surface of the bipolar current collector being opposite the first surface of the bipolar current collector; a first ion channel blocker positioned along a first edge of the bipolar current collector; a second ion channel blocker positioned along a second edge of the bipolar current collector and a third ion channel blocker positioned along a third edge of the bipolar current collector, the second and third edges of the bipolar current collector being orthogonal to the first edge; and An ion-conductive gel electrolyte is formed on the anode coating and the cathode coating.

9. The battery cell according to claim 8, wherein: The first ion channel blocker, the second ion channel blocker, and the third ion channel blocker each comprise a metal ion channel blocker, and wherein the metal ion channel blocker comprises a non-ion conductive gel having infinite viscosity at zero shear rate.

10. The battery cell according to claim 9, wherein The non-ion conductive gel is formed from a viscous solution comprising an organic solvent and a gelling polymer mixture, wherein the gelling polymer mixture comprises a cross-linkable polymer, a rheology modifier and a cross-linking initiator.

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