Electrode foil wrinkle removing belt

Abstract

Aspects of the present disclosure include an electrode calendering system having an electrode foil wrinkle removal tape and a method of manufacturing an electrode using the electrode calendering system. An exemplary system includes a top roller press and a bottom roller press separated from the top roller press by a gap. The gap includes a distance selected to receive a current collector having an exposed portion and a coated portion having an active electrode material having a first thickness thereon. The system also includes a dewrinkling tape having a second thickness selected based on the first thickness to uniformly distribute stress across the exposed portion and the coated portion of the current collector during a calendering process for forming the pressed electrode.

Description

Technical Field

[0001] The present disclosure relates to battery cell manufacturing, and in particular to an electrode calendering system having an electrode foil de-wrinkling belt. Background Art

[0002] Electrodes are widely used in a range of devices for storing electrical energy, including primary (non-rechargeable) battery cells, secondary (rechargeable) battery cells, fuel cells, and capacitors. An ideal electrode needs to balance various electrical energy storage characteristics, 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 typically include current collectors to supplement or otherwise improve these electrical energy storage characteristics. Current collectors can be added to provide higher specific conductance, and the available contact area can be increased to minimize the interfacial contact resistance between the electrode and its terminals.

[0003] The current collector is typically a sheet of conductive material to which an active electrode material is attached. Aluminum foil, aluminum alloys, copper alloys, stainless steel, and titanium foil are commonly used as current collectors for electrodes. In some electrode manufacturing processes, for example, a film comprising activated carbon powder (i.e., active electrode material) is attached to a thin aluminum or copper foil using an adhesive layer. In order to improve the quality of the interfacial bonding 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 (e.g., a calender). This method is generally referred to as calendering. Therefore, the manufacture of an electrode typically involves the manufacture of an active electrode material film and laminating the film to a current collector. Summary of the invention

[0004] In one exemplary embodiment, an electrode calendaring system having an electrode foil de-wrinkling belt for manufacturing an electrode is provided. The system includes a top roller press and a bottom roller press separated from the top roller press by a gap. The gap includes a distance selected to accommodate a current collector having an exposed portion and a coated portion having a first thickness of active electrode material thereon. The system also includes a de-wrinkling belt having a second thickness selected based on the first thickness to evenly distribute stress on the exposed and coated portions of the current collector during a calendaring process for forming a pressed electrode.

[0005] In addition to one or more features described herein, in some embodiments, the system includes at least one of a belt guide roller and a tensioning roller, wherein the at least one of the belt guide roller and the tensioning roller is configured to align the wrinkle removal belt with the exposed portion of the collector.

[0006] In some embodiments, the system includes a servo system coupled to at least one of the belt guide roller and the tension roller. The servo system may include a servo motor and one or more rollers configured to reposition the dewrinkling belt to maintain alignment with the exposed portion of the current collector.

[0007] In some embodiments, the wrinkle-removing tape is a top wrinkle-removing tape located on the top surface of the exposed portion of the current collector. In some embodiments, the wrinkle-removing tape is a bottom wrinkle-removing tape located on the bottom surface of the exposed portion of the current collector.

[0008] In some embodiments, the wrinkle-removing belt is one of a top wrinkle-removing belt located on the top surface of the exposed portion of the collector and a bottom wrinkle-removing belt located on the bottom surface of the exposed portion of the collector, and the system further includes a second wrinkle-removing belt, which is the other of the top wrinkle-removing belt and the bottom wrinkle-removing belt.

[0009] In some embodiments, the second thickness of the wrinkle-removing belt is gradient.

[0010] In some embodiments, the wrinkle removal tape is located on a top surface of the exposed portion of the current collector, and the second thickness of the wrinkle removal tape includes a positive taper that increases toward an edge of the current collector.

[0011] In some embodiments, the wrinkle removal tape is located on a bottom surface of the exposed portion of the current collector, and the second thickness of the wrinkle removal tape includes a positive taper that increases toward an edge of the current collector.

[0012] In another exemplary embodiment, a method for manufacturing an electrode is provided. The method includes providing a top roller press and providing a bottom roller press separated from the top roller press by a gap. The gap includes a distance selected to accommodate a current collector. The current collector includes an exposed portion and a coated portion having a first thickness of active electrode material thereon. The method includes providing a dewrinkling belt having a second thickness selected based on the first thickness to evenly distribute stress on the exposed portion and the coated portion of the current collector during a calendaring process for forming a pressed electrode.

[0013] In some embodiments, the method includes providing at least one of a belt guide roller and a tension roller configured to align the dewrinkling belt with the exposed portion of the current collector.

[0014] In some embodiments, the method includes providing a servo system coupled to at least one of the belt guide roller and the tension roller. The servo system includes a servo motor and one or more rollers configured to reposition the dewrinkling belt to maintain alignment with the exposed portion of the current collector.

[0015] In some embodiments, the wrinkle-removing strip includes a top wrinkle-removing strip positioned on a top surface of the exposed portion of the current collector.

[0016] In some embodiments, the wrinkle-removing strip includes a bottom wrinkle-removing strip positioned on a bottom surface of the exposed portion of the current collector.

[0017] In some embodiments, the wrinkle-removing belt includes one of a top wrinkle-removing belt located on the top surface of the exposed portion of the current collector and a bottom wrinkle-removing belt located on the bottom surface of the exposed portion of the current collector. In some embodiments, the method further includes providing a second wrinkle-removing belt, which is the other of the top wrinkle-removing belt and the bottom wrinkle-removing belt.

[0018] In some embodiments, the second thickness of the wrinkle-removing belt is gradient.

[0019] In some embodiments, the wrinkle removal tape is located on a top surface of the exposed portion of the current collector, and the second thickness of the wrinkle removal tape includes a positive taper that increases toward an edge of the current collector.

[0020] In some embodiments, the wrinkle removal tape is located on a bottom surface of the exposed portion of the current collector, and the second thickness of the wrinkle removal tape includes a positive taper that increases toward an edge of the current collector.

[0021] In some embodiments, the wrinkle-removing tape is configured as a plurality of individual tapes that are positioned on the exposed portion of the current collector for a pass-through coating application.

[0022] The above features and advantages and other features and advantages of the present disclosure are apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other features, advantages, and details appear, by way of example only, from the following detailed description, which refers to the accompanying drawings.

[0024] Figure 1 is a vehicle configured according to one or more embodiments;

[0025] Figure 2 is an exemplary configuration of an electrode calendaring system according to one or more embodiments;

[0026] Figure 3A is a diagram of an electrode calendaring system according to one or more embodiments;

[0027] Figure 3B is a diagram of an alternative electrode calendaring system according to one or more embodiments;

[0028] Figure 4Ais a diagram of an alternative electrode calendaring system according to one or more embodiments;

[0029] Figure 4B is a diagram of an alternative electrode calendaring system according to one or more embodiments;

[0030] Figure 4C is a diagram of an alternative electrode calendaring system according to one or more embodiments;

[0031] Figure 5A is a diagram of an alternative electrode calendaring system according to one or more embodiments;

[0032] Figure 5B is a diagram of an alternative electrode calendaring system according to one or more embodiments;

[0033] Figure 5C is a diagram of an alternative electrode calendaring system according to one or more embodiments; and

[0034] Figure 6 is a flow diagram according to one or more implementations. DETAILED DESCRIPTION

[0035] 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.

[0036] The electrode generally includes a current collector to supplement or otherwise improve the energy storage characteristics of the final integrated device (e.g., battery). The current collector generally includes a conductive material sheet (e.g., aluminum foil, copper foil, etc.) to which the active electrode material is attached. In order to improve the quality of the interface bonding between the film of the active electrode material and the current collector, the combination of the film and the current collector is processed in a pressure laminator. Therefore, the manufacture of the electrode generally involves the manufacture of the active electrode material film and laminating the film to the current collector (so-called calendering process).

[0037] Calendering can be generally defined as the extrusion of dry electrodes (the latter are usually made by coating and drying of electrode slurries) to reduce their porosity, improve particle contact, and enhance energy or power density. Conventional calendering processes have been used to improve various aspects of battery technology by providing, for example, higher specific conductance, larger contact area, and lower contact resistance in electrodes. However, there are several challenges in optimizing the calendering process.

[0038] For example, one such challenge is that when a lower porosity is targeted, rolling an electrode (e.g., a cathode) onto a current collector substrate (e.g., a foil substrate such as aluminum, stainless steel, and titanium) can produce wrinkle defects. Wrinkle defects (also known as uneven elongation) exist at the interface between the coated portions of the current collector (i.e., those portions with the pressed electrode film) and the uncoated portions (i.e., the exposed portions of the current collector) and are caused by the different material properties and thicknesses of the electrode and substrate materials. These defects worsen as the resulting porosity decreases, which means that relatively low-porosity electrodes themselves suffer from more prevalent wrinkle defects.

[0039] While there are several approaches to mitigate wrinkle defects, each approach has some tradeoffs. For example, a naive approach is to increase the porosity target, resulting in a proportional reduction in wrinkle defects, but a decrease in electrode conductivity. Another approach is to completely cover the substrate so that there are no interfaces where wrinkle defects can occur. The tradeoff here is that the bare foil portions of the current collector (i.e., those portions not covered by active electrode material) are ideal for use as battery terminals, and simply removing the bare foil portions reduces battery efficiency.

[0040] The present disclosure introduces a new electrode calendaring system with an electrode foil de-wrinkling belt and a method for manufacturing an electrode using the electrode foil de-wrinkling belt. Rather than increasing the porosity target or removing (or reducing) the bare foil portion of the electrode, the electrode calendaring system described herein utilizes the electrode foil de-wrinkling belt to evenly distribute stress during the calendaring process. In some embodiments, the de-wrinkling belt is positioned above the bare foil portion of the current collector at the interface with the coated portion to transfer the extrusion force from the calendaring roller to the bare foil, maintaining an equal extrusion to the coated portion. Maintaining equal extrusion during the calendaring process reduces (or completely eliminates) wrinkle defects and results in uniform elongation on all portions of the pressed electrode. In some embodiments, a tensioning roller system is used to position the de-wrinkling belt above the current collector to improve alignment. In some embodiments, the de-wrinkling belt is actively guided (positioned and repositioned) onto the current collector using a servo system that tracks the positioning of the de-wrinkling belt and / or the current collector to improve alignment.

[0041] An electrode calendaring system utilizing a wrinkle-removing belt configured according to one or more embodiments provides several technical advantages over existing designs. Notably, the improved manufacturing system and associated processes described herein can be used to produce electrodes having no (or greatly reduced) wrinkle defects and relatively improved elongation. Batteries built from electrodes without wrinkles and with more uniform elongation offer a range of improved battery properties because these defects can reduce electrode integrity (e.g., wrinkles can result in poor adhesion between the coated electrode film and the current collector, resulting in relatively weak adhesion areas that are susceptible to delamination or peeling issues), increase resistance (wrinkles and thickness variations can create gaps or areas of reduced contact between the electrode material and the current collector that can impede the flow of electrons), increase degradation and reduce cycle life (electrodes with wrinkles and / or non-uniform elongation can experience increased stress and strain during charge-discharge cycles due to inconsistent mechanical properties, which can lead to accelerated degradation, cracking, or even electrode failure), increase thermal instability (wrinkles can trap electrolyte and inhibit heat dissipation, resulting in localized hot spots that can degrade the electrolyte), and reduce capacity and energy density (wrinkles and elongation defects can result in non-uniform thickness distribution over the electrode surface, and these non-uniformities can result in reduced active material utilization, reduced capacity, and compromised energy density in the battery). Other advantages exist. For example, while a roller press can be reconfigured to integrate support material application and removal, aspects of the present disclosure can be utilized to modify an existing roller press to reduce wrinkle defects by adding a wrinkle removal belt and several positioning and tensioning rollers without redesigning the main rollers / calendering rolls. Finally, using a wrinkle removal belt as described herein to reduce wrinkle and elongation defects eliminates the need for foil annealing and foil rigidification steps and the need to introduce ridges in the current collector, each of which is a technique commonly relied upon for defect reduction but is known to weaken the foil. In addition, the annealing and foil rigidification steps are energy consuming and expensive.

[0042] According to an exemplary embodiment, a vehicle Figure 1 1. The vehicle 100 is generally indicated at 100. The vehicle 100 is shown in the form of an automobile having a body 102. The body 102 includes a passenger compartment 104, within which a steering wheel, front seats, and rear passenger seats (not shown separately) are arranged. A plurality of components are arranged within the body 102, including, for example, an electric motor 106 (shown by a projection under the front hood). The electric motor 106 is shown only for ease of illustration and discussion. It should be understood that the configuration, location, size, arrangement, etc. of the electric motor 106 are not meant to be particularly limited, and all such configurations (including multi-motor configurations) are within the intended scope of the present disclosure.

[0043] The electric motor 106 is powered via a battery pack 108 (shown by 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 is not meant to be particularly limited, and all such configurations (including expanded configurations) are within the intended scope of the present disclosure. In addition, while the present disclosure is primarily discussed in the context of a battery pack 108 configured for an electric motor 106 of the vehicle 100, the aspects described herein may be similarly incorporated within any system (vehicle, building, or other) 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 cells having electrodes with enhanced edge quality (i.e., uniform elongation and reduced or eliminated wrinkling). In some embodiments, the electrode calendaring system is modified to include a dewrinkling belt (see Figure 2 and 3A In some embodiments, a servo system is used to actively position the wrinkle removal belt (see Figure 3B In some embodiments, the wrinkle removal tape is located on both surfaces (top and bottom) of the current collector (see Figure 4A In some embodiments, the wrinkle removal tape is located on one of the surfaces (top or bottom) of the current collector (see Figure 4B and 4C In some embodiments, the wrinkle removal tape is configured as multiple tapes positioned across the bare foil portion of the current collector for lane coating applications (see Figure 5A In some embodiments, the wrinkle-removing tape is located on one surface (top or bottom) of the current collector for a single coating (see Figure 5B and 5C ).

[0045] Figure 2 2 shows an exemplary configuration of an electrode calendaring system 200 according to one or more embodiments. Figure 2As shown, the electrode calendering system 200 may include a coated current collector 202, which passes between a top roller press 204 and a bottom roller press 206 for calendering. In some embodiments, a series of guide rollers 208 are used to pass the coated current collector 202 (also referred to as a coated web) through the top roller press 204 and the bottom roller press 206. In some embodiments, after the coating process (not shown separately), the coated current collector 202 is wound into a coated electrode roll. In some embodiments, the coated current collector 202 is unwound from the coated electrode roll and connected to the guide roller 208 for calendering. After calendering (e.g., after passing between the top roller press 204 and the bottom roller press 206), the coated current collector 202 may be referred to as a pressed electrode 210.

[0046] In some embodiments, the coated current collector 202 includes a current collector coated with an active electrode material. Although not intended to be particularly limiting, the active electrode material may include, for example, various cathode or anode materials (depending on the requirements of the specific application), 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 manganese iron phosphate (LMFP), lithium rich manganese (LMR), lithium manganese oxide (LMO), graphite, silicon, silicon-graphite composites, tin, tin oxide (SnO2), lithium titanate (Li4Ti5O 12 , LTO), sulfur and lithium-sulfur (Li-S) composite materials. Lithium metal (Li) and / or lithium alloys such as lithium-antimony (Li-Sb), lithium-aluminum (Li-Al) and lithium-germanium (Li-Ge).

[0047] Similarly, the current collector (also referred to as mesh or bare foil) is not meant to be particularly limited, but may include, for example, conductive metal sheets, such as aluminum foil, stainless steel, and titanium foil. Other materials are possible, such as semi-metals (e.g., tin, graphite), alloys of metals and / or semi-metals, conductive two-dimensional wire meshes, conductive three-dimensional wire meshes, conductive foams, etc.

[0048] In some embodiments, the top roller press 204 and the bottom roller press 206 are positioned to apply pressure to the coated current collector 202. The process (called calendering) is designed to improve the density, uniformity and overall performance of the resulting pressed electrode 210 by squeezing and compacting the electrode material onto a portion of the current collector. The top roller press 204 and the bottom roller press 206 can be made of durable materials (e.g., steel) and can be manufactured to have precision surfaces (e.g., sub-10 micron tolerances) to ensure uniform pressure distribution. In some embodiments, the top roller press 204 is positioned vertically above the bottom roller press 206, and the gap (not shown separately) can be adjusted by moving (e.g., hydraulically) one or two of the top roller press 204 and the bottom roller press 206 to control the amount of pressure applied.

[0049] In some embodiments, the electrode calendaring system 200 includes several control parameters, such as roller temperature (upper and / or lower), calendaring pressure, gap distance, and line speed. In some embodiments, the roller temperature is at most 150 degrees Celsius, the pressure is at most 10 MPa, and the line speed is 110 meters / minute, but other calendaring configurations are within the expected scope of the present disclosure. In some embodiments, the gap between the top roller press 204 and the bottom roller press 206 can be adjusted (hydraulically or otherwise) to the desired thickness of the pressed electrode 210.

[0050] When the top roller 204 and / or the bottom roller 206 apply pressure, the coated current collector 202 is compressed. This helps to improve the density of the pressed electrode 210, remove voids and air pockets, and enhance the contact between the active electrode material and the current collector. The calendaring process also causes the thickness of the coated current collector 202 to be reduced because the pressed electrode 210 is flattened under the pressure of the rollers.

[0051] In some embodiments, electrode calendaring system 200 includes top de-wrinkling belt 212 and / or bottom de-wrinkling belt 214. In some embodiments, the presence of top de-wrinkling belt 212 and / or bottom de-wrinkling belt 214 ensures that the stress applied to the bare foil portion of coated current collector 202 is the same as the stress applied to the coated portion of coated current collector 202.

[0052] In some embodiments, the thickness of the top de-wrinkling tape 212 and / or the bottom de-wrinkling tape 214 for a given application is selected to ensure uniform distribution of stress. It is observed that the thickness required to achieve uniform stress distribution will vary based on the loading (e.g., milligrams per square centimeter) and density of the electrode material, the material selected for the current collector, and the target thickness of the pressed electrode 210. In addition, the tape thickness can be selected based on any one of a plurality of design and / or target parameters, such as bending strength, strain, elongation, electrode thickness, and / or yield strength. The tape thickness can also vary based on additional factors, including but not limited to electrode formulation, surface roughness, tensile properties, etc.

[0053] The top de-wrinkling belt 212 and / or the bottom de-wrinkling belt 214 may be made of a material having a known elasticity at a designed calendering pressure. For example, although not intended to be particularly limiting, the top de-wrinkling belt 212 and / or the bottom de-wrinkling belt 214 may be made of silicon mixed with a polymer such as polypropylene, thermoplastic polymers such as polyethylene terephthalate (PET) and polyvinylidene fluoride (PVDF), polyethylene (PE) including low-density polyethylene (LDPE) and high-density polyethylene (HDPE), polytetrafluoroethylene (PTFE), polyamides such as nylon, synthetic rubbers such as neoprene, mixed materials with glass fiber, silica, etc., polymers and metal laminates with rubber, etc. In some embodiments, the top de-wrinkling belt 212 and / or the bottom de-wrinkling belt 214 may be made of a highly elastic material to minimize tool wear and allow for continuous calendering operations over several cycles. As used herein, a "highly elastic" material refers to a material having a Young's modulus of less than 3 gigapascals (GPa). In some embodiments, the highly elastic material has a Young's modulus of less than 1 GPa, such as rubber (about 0.01 to 0.1 GPa). In some embodiments, the highly elastic material has a Young's modulus of less than 0.1 GPa, such as an elastomer (about 0.001 to 0.1 GPa).

[0054] In some embodiments, the top de-wrinkling belt 212 and / or the bottom de-wrinkling belt 214 pass through the top roller 204 and the bottom roller 206 using a series of belt guide rollers 216 in a manner similar to that previously described with respect to the coated current collector 202 and guide rollers 208. In some embodiments, the top de-wrinkling belt 212 and the bottom de-wrinkling belt 214 pass through the top roller 204 and the bottom roller 206 using separate belt guide rollers 216 (as shown), but other configurations having shared belt guide rollers 216 are also within the contemplated scope of the present disclosure.

[0055] In some embodiments, the electrode coating system 200 includes one or more tension rollers 218 coupled to the top de-wrinkling belt 212 and / or the bottom de-wrinkling belt 214 and configured to maintain a consistent and controlled tension as the top de-wrinkling belt 212 and / or the bottom de-wrinkling belt 214 passes through the calendering process. In some embodiments, each set of individual belt guide rollers 216 includes one or more tension rollers 218 (as shown).

[0056] In some embodiments, electrode coating system 200 includes a support structure 220 for top roller 204, bottom roller 206, guide roller 208, belt guide roller 216, and / or tension roller 218. Support structure 220 may include, for example, a steel frame, although other materials are within the contemplated scope of the present disclosure.

[0057] Figure 3A 1 shows a view of an electrode calendaring system 300 according to one or more embodiments. In some embodiments, the electrode calendaring system 300 is a calendaring system (e.g., Figure 2 A part of the electrode calendering system 200 in FIG. Figure 3A As shown, the electrode calendaring system 300 may include a top roller 204, a bottom roller 206, a top de-wrinkling belt 212, and a bottom de-wrinkling belt 214 configured and arranged as shown.

[0058] In some embodiments, current collector 302 is coated with active electrode material 304 and passed between top roller 204 and bottom roller 206 for calendaring. In some embodiments, both surfaces (e.g., top and bottom) of current collector 302 are coated with active electrode material 304 (as shown). Alternatively, a single surface (e.g., top or bottom) of current collector 302 can be coated with active electrode material 304 (see Figure 5B and 5C ). The current collector 302 and the active electrode material 304 coated thereon together define a coated current collector, such as for Figure 2 A coated current collector 202 is depicted.

[0059] In some embodiments, the top de-wrinkling belt 212 and the bottom de-wrinkling belt 214 can be designed to have a thickness that simulates the thickness of the coating of the active electrode material 304 pressed on the current collector 302. For example, the top roller 204 and the bottom roller 206 can be separated by a gap G, and the top de-wrinkling belt 212 and the bottom de-wrinkling belt 214 can each have a thickness selected based on the thickness of the exposed portion of the current collector 302 to ensure that the gap G is filled (as shown). In this way, the thickness difference between the coated and uncoated portions of the current collector 302 is greatly minimized (if not completely removed), thereby reducing wrinkle defects and providing uniform elongation without sacrificing porosity targets and / or bare foil surface area. Therefore, the top de-wrinkling belt 212 and the bottom de-wrinkling belt 214 are used to more evenly distribute the calendering stress during the calendering process, thereby improving the edge quality in the resulting pressed electrode (e.g., pressed electrode 210).

[0060] Figure 3B 1 shows a diagram of an alternative electrode calendaring system 350 according to one or more embodiments. In some embodiments, the electrode calendaring system 350 is a calendaring system (e.g., Figure 2 A part of the electrode calendering system 200 in FIG. Figure 3B As shown, the electrode calendaring system 350 may include a top roller 204, a bottom roller 206, a top de-wrinkling belt 212, and a bottom de-wrinkling belt 214 configured and arranged as shown.

[0061] In some embodiments, current collector 302 is coated with active electrode material 304 and passed between top roller 204 and bottom roller 206 for calendaring. In some embodiments, both surfaces (e.g., top and bottom) of current collector 302 are coated with active electrode material 304 (as shown). Alternatively, a single surface (e.g., top or bottom) of current collector 302 can be coated with active electrode material 304 (see Figure 5B and 5C ). The current collector 302 and the active electrode material 304 coated thereon together define a coated current collector, such as for Figure 2 A coated current collector 202 is depicted.

[0062] In some embodiments, the top and bottom wrinkle-removing tapes 212, 214 can be designed to have a thickness that simulates the thickness of a coating of active electrode material 304 pressed onto the current collector 302, as previously described for Figure 3AAs described. For example, the top roller 204 and the bottom roller 206 can be separated by a gap G, and the top de-wrinkling belt 212 and the bottom de-wrinkling belt 214 can each have a thickness selected based on the thickness of the exposed portion of the collector 302 to ensure that the gap G is filled (as shown). In this way, the thickness difference between the coated and uncoated portions of the collector 302 is greatly minimized (if not completely removed), thereby reducing wrinkle defects and providing uniform elongation without sacrificing porosity targets and / or bare foil surface area. Therefore, the top de-wrinkling belt 212 and the bottom de-wrinkling belt 214 are used to more evenly distribute the calendering stress during the calendering process, thereby improving the edge quality in the resulting pressed electrode (e.g., pressed electrode 210).

[0063] In some embodiments, the electrode calendaring system 350 includes one or more servo systems 352 to actively position the top de-wrinkling belt 212 and the bottom de-wrinkling belt 214 relative to the current collector 302 and / or the active electrode material 304. In some embodiments, the servo system 352 can be configured to ensure (or improve within tool limitations) alignment between two or more of the top de-wrinkling belt 212, the bottom de-wrinkling belt 214, the current collector 302, and the active electrode material 304.

[0064] In some embodiments, each servo system 352 includes a servo motor 354 and one or more rollers 356. The servo motor 354 is responsible for driving and / or repositioning the roller 356 and / or other guide mechanisms (not shown separately) as needed to accurately position the upper de-wrinkling belt 212 and / or the lower de-wrinkling belt 214. Although not intended to be particularly limited, the servo motor 354 may include a high torque motor with a torque rating of about 10 Newton meters, speed control, and precise positioning capabilities. The servo system 352 may include one or more sensors (not shown separately) coupled to the servo motor 354 and / or the roller 356. The sensor may include, for example, a position sensor (e.g., an optical encoder or a linear position sensor) that continuously and / or periodically monitors the position of the upper de-wrinkling belt 212, the lower de-wrinkling belt 214, the current collector 302, and / or the active electrode material 304, and a tension sensor that is configured to measure the tension in the upper de-wrinkling belt 212, the lower de-wrinkling belt 214, and / or the current collector 302. In some embodiments, the servo system 352 may include control electronics (not separately shown), such as a microcontroller and / or a dedicated servo controller, to process feedback from the sensors and generate control signals for the servo motors.

[0065] Figure 4A 1 shows a diagram of an alternative electrode calendaring system 400 according to one or more embodiments. In some embodiments, the electrode calendaring system 400 is a calendaring system (e.g., Figure 2 A part of the electrode calendering system 200 in FIG. Figure 4A As shown, the electrode calendaring system 400 may include a top roller 204, a bottom roller 206, a top de-wrinkling belt 212, and a bottom de-wrinkling belt 214 configured and arranged as shown. Figure 4A A dual belt configuration having both a top de-wrinkling belt 212 and a bottom de-wrinkling belt 214 is depicted.

[0066] Figure 4B 1 shows a diagram of an alternative electrode calendaring system 410 according to one or more embodiments. In some embodiments, the electrode calendaring system 410 is a calendaring system (e.g., Figure 2 A part of the electrode calendering system 200 in FIG. Figure 4B As shown, the electrode calendaring system 410 may include a top roller 204, a bottom roller 206, and a top de-wrinkling belt 212 configured and arranged as shown. Figure 4B A single belt configuration having only the upper wrinkle-removing belt 212 is depicted.

[0067] like Figure 4B As shown, top de-wrinkling strip 212 can have a tapered profile (as shown, a positive taper that increases toward the edge of current collector 302). In some embodiments, the shape, thickness, slope, and / or taper of top de-wrinkling strip 212 is varied to evenly distribute stress on the coated portion and bare foil of current collector 302. Figure 4B The particular taper shown in is for ease of illustration and discussion only. The upper dewrinkling belt 212 can have a tapered profile having a positive slope and / or a negative slope. Figure 4B The slopes shown in are not meant to be particularly limited. Other tapered profiles are possible, including linear and nonlinear profiles, and all of these configurations are within the intended scope of the present disclosure. For example, the upper wrinkle removal belt 212 can have a spherical, curved, sharp, square, triangular and / or patterned tapered profile as desired.

[0068] Figure 4C 4 shows an alternative electrode calendaring system 420 according to one or more embodiments. In some embodiments, the electrode calendaring system 420 is a calendaring system (e.g., Figure 2 A part of the electrode calendering system 200 in FIG. Figure 4C As shown, the electrode calendaring system 420 may include the top roller 204, the bottom roller 206, and the bottom de-wrinkling belt 214 configured and arranged as shown. Figure 4C A single belt configuration having only a bottom wrinkle-removing belt 214 is depicted.

[0069] like Figure 4CAs shown, bottom dewrinkling band 214 can have a tapered profile (as shown, a positive taper that increases toward the edge of current collector 302). In some embodiments, the shape, thickness, slope, and / or taper of bottom dewrinkling band 214 is varied to evenly distribute stress on the coated portion and bare foil of current collector 302. Figure 4C The specific taper shown in is for ease of illustration and discussion only. The bottom dewrinkling belt 214 can have a tapered profile having a positive slope and / or a negative slope. Figure 4C The slopes shown in are not meant to be particularly limited. Other tapered profiles are possible, including linear and nonlinear profiles, and all of these configurations are within the intended scope of the present disclosure. For example, the bottom wrinkle removal belt 214 can have a spherical, curved, sharp, square, triangular and / or patterned tapered profile as desired.

[0070] Figure 5A 1 shows a diagram of an alternative electrode calendaring system 500 according to one or more embodiments. In some embodiments, the electrode calendaring system 500 is a calendaring system (e.g., Figure 2 A part of the electrode calendering system 200 in FIG. Figure 5A As shown, the electrode calendaring system 500 may include a top roller 204, a bottom roller 206, a top de-wrinkling belt 212, and a bottom de-wrinkling belt 214 configured and arranged as shown. Figure 5A A multi-belt configuration is depicted in which each of upper de-wrinkling belt 212 and lower de-wrinkling belt 214 are divided into two or more belts on the surface of their respective current collector 302 .

[0071] Figure 5B 1 shows a diagram of an alternative electrode calendaring system 510 according to one or more embodiments. In some embodiments, the electrode calendaring system 510 is a calendaring system (e.g., Figure 2 A part of the electrode calendering system 200 in FIG. Figure 5B As shown, the electrode calendaring system 510 may include a top roller 204, a bottom roller 206, and a top dewrinkling belt 212 configured and arranged as shown. Figure 5B A single belt configuration with only upper dewrinkling belt 212 is depicted because active electrode material 304 is coated only on top surface 502 of current collector 302 (eg, a single coating process).

[0072] Figure 5C 1 shows a diagram of an alternative electrode calendaring system 520 according to one or more embodiments. In some embodiments, the electrode calendaring system 520 is a calendaring system (e.g., Figure 2 A part of the electrode calendering system 200 in FIG. Figure 5CAs shown, the electrode calendaring system 520 may include a top roller 204, a bottom roller 206, and a bottom de-wrinkling belt 214 configured and arranged as shown. Figure 5C A single belt configuration with only a bottom dewrinkling belt 214 is depicted because the active electrode material 304 is coated only on the bottom surface 504 of the current collector 302 (eg, a single coating process).

[0073] Reference now Figure 6 , a flowchart 600 for manufacturing an electrode using an electrode calendaring system with an electrode foil de-wrinkling belt is generally shown according to an embodiment. Figure 1-5C Flowchart 600 is described and may include Figure 6 Although depicted in a specific order, Figure 6 The blocks depicted in the drawings may be rearranged, subdivided, and / or combined.

[0074] At block 602 , the method includes providing a top roller press.

[0075] At block 604, the method includes providing a bottom roller separated from the top roller by a gap. In some embodiments, the gap includes a distance selected to accommodate the current collector. In some embodiments, the current collector includes an exposed portion and a coated portion of an active electrode material having a first thickness.

[0076] At block 606 , the method includes providing a dewrinkling tape having a second thickness selected based on the first thickness to evenly distribute stress on bare and coated portions of the current collector during a calendaring process for forming a pressed electrode.

[0077] In some embodiments, the method includes providing at least one of a belt guide roller and a tension roller configured to align the dewrinkling belt with the exposed portion of the current collector.

[0078] In some embodiments, the method includes providing a servo system coupled to at least one of the belt guide roller and the tension roller. The servo system may include a servo motor and one or more rollers configured to reposition the dewrinkling belt to maintain alignment with the exposed portion of the current collector.

[0079] In some embodiments, the wrinkle-removing tape is a top wrinkle-removing tape that is positioned on the top surface of the exposed portion of the current collector.

[0080] In some embodiments, the wrinkle-removing tape is a bottom wrinkle-removing tape located on the bottom surface of the exposed portion of the current collector.

[0081] In some embodiments, the wrinkle-removing tape is one of a top wrinkle-removing tape located on the top surface of the exposed portion of the current collector and a bottom wrinkle-removing tape located on the bottom surface of the exposed portion of the current collector. In some embodiments, the method further includes providing a second wrinkle-removing tape, the second wrinkle-removing tape being the other of the top wrinkle-removing tape and the bottom wrinkle-removing tape.

[0082] In some embodiments, the second thickness of the wrinkle-removing belt is gradient.

[0083] In some embodiments, the wrinkle removal tape is located on a top surface of the exposed portion of the current collector, and the second thickness of the wrinkle removal tape has a positive taper that increases toward an edge of the current collector.

[0084] In some embodiments, the wrinkle-removing tape is located on a bottom surface of the exposed portion of the current collector, and the second thickness of the wrinkle-removing tape is a positive taper that increases toward an edge of the current collector.

[0085] In some embodiments, the wrinkle-removing tape is configured as a plurality of individual tapes positioned on the bare foil portion of the current collector for driveway coating applications.

[0086] The term "one" does not indicate a limitation of quantity, but rather indicates the presence of at least one of the referenced items. Unless the context clearly indicates otherwise, the term "or" means "and / or". References to "aspects" throughout the specification mean that a particular element (e.g., a 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. In addition, it should be understood that the described elements may be combined in any suitable manner in the various aspects.

[0087] 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.

[0088] Unless otherwise indicated herein, all test standards are the most current 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.

[0089] 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.

[0090] Although the above disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted for its elements without departing from its scope. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the disclosure without departing from the basic scope of the disclosure. Therefore, it is intended that the disclosure is not limited to the specific embodiments disclosed, but will include all embodiments falling within its scope.

Claims

1. A system for manufacturing an electrode, the system comprising: Top roller press; a bottom roller press separated from the top roller press by a gap, the gap comprising a distance selected to accommodate a current collector comprising a bare portion and a coated portion having a first thickness of active electrode material thereon; as well as A wrinkle-removing tape includes a second thickness selected based on the first thickness to evenly distribute stress on bare and coated portions of the current collector during a calendaring process for forming a pressed electrode.

2. The system of claim 1 further comprising at least one of a belt guide roller and a tension roller, wherein the at least one of the belt guide roller and the tension roller is configured to align the wrinkle removal belt with the exposed portion of the current collector.

3. The system according to claim 2 further includes a servo system, which is connected to at least one of the belt guide roller and the tensioning roller, and the servo system includes a servo motor and one or more rollers, and the one or more rollers are configured to reposition the dewrinkling belt to maintain alignment with the exposed portion of the collector.

4. The system of claim 1, wherein the wrinkle-removing strip comprises a top wrinkle-removing strip positioned on a top surface of the exposed portion of the current collector.

5. The system of claim 1, wherein the wrinkle-removing strip comprises a bottom wrinkle-removing strip located on a bottom surface of the exposed portion of the current collector.

6. A system according to claim 1, wherein the wrinkle-removing belt includes one of a top wrinkle-removing belt located on the top surface of the exposed portion of the collector and a bottom wrinkle-removing belt located on the bottom surface of the exposed portion of the collector, and the system also includes a second wrinkle-removing belt, which includes the other of the top wrinkle-removing belt and the bottom wrinkle-removing belt.

7. The system according to claim 1, wherein: The second thickness of the wrinkle-removing belt is gradually varied.

8. The system of claim 7, wherein the wrinkle removal tape is located on a top surface of the exposed portion of the current collector, and the second thickness of the wrinkle removal tape comprises a positive taper that increases toward an edge of the current collector.

9. The system of claim 7, wherein the wrinkle removal tape is located on a bottom surface of the exposed portion of the current collector, and the second thickness of the wrinkle removal tape comprises a positive taper that increases toward an edge of the current collector.

10. The system according to claim 1, wherein: The wrinkle removal tape is configured as a plurality of individual tapes that are positioned over the exposed portion of the current collector for a lane coating application.

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