SYSTEM FOR MANUFACTURING ELECTRODES WITH IMPROVED EDGE QUALITY AND METHOD

Abstract

Aspects of the disclosure include an electrode calendering system for producing electrodes with improved edge quality. An exemplary system comprises a supply of active material, including an electrode material, and a coating roller connected to the supply of active material. The coating roller is arranged to coat a current collector with the electrode material. A counter roller is arranged to transfer the current collector to the coating roller. The system includes at least one roller with bare film support material and one roller with coated film support material. The roller with the bare film support material is arranged to apply a support material to a first portion of the current collector before the current collector is coated with the electrode material.The roller with the coated film carrier material is attached in such a way that the carrier material is applied to the first part of the current collector after the current collector has been coated with the electrode material.

Description

INTRODUCTION

[0001] The present disclosure relates to the manufacture of battery cells, and in particular to the calendering of electrodes with improved edge quality. Prior art reference is made to JP 2000-251 942 A, JP 2005-183 181 A, JP 2005-216 723 A, and JP 2002-159 899 A.

[0002] Electrodes are used in a variety of devices that store electrical energy, including primary (non-rechargeable) battery cells, secondary (rechargeable) battery cells, fuel cells, and capacitors. An ideal electrode must balance various electrical energy storage properties, such as energy density, power density, maximum charge rate, internal leakage current, equivalent series resistance (ESR), cycle endurance, high electrical conductivity, and low tortuosity. Electrodes often incorporate current collectors to complement or otherwise enhance these electrical energy storage properties. Current collectors can be added to achieve higher conductivity and increase the available contact area to minimize the interfacial contact resistance between the electrode and its terminal.

[0003] A current collector is typically a plate of conductive material to which the electrode active material is attached. Aluminum film, stainless steel, and titanium film are commonly used as the current collector for an electrode. For example, in some electrode manufacturing processes, a film comprising activated carbon powder (i.e., the electrode active material) is attached to a thin aluminum film with an adhesive layer. To improve the quality of the interfacial bond between the film of electrode active material and the current collector, the combination of the film and the current collector is processed in a pressure laminator, such as a calender. This process is commonly called calendering. Therefore, the manufacture of an electrode typically involves preparing a film of electrode active material and laminating this film onto a current collector. SUMMARY

[0004] The present invention is defined by the features of the two appended independent claims. Advantageous further developments are provided in the following description and in the dependent claims.

[0005] In an exemplary embodiment, a system for manufacturing electrodes with improved edge quality is developed. The system includes a supply of active material with an electrode material and a coating roll connected to the supply of active material. The coating roll is arranged to coat a current collector with the electrode material. A counter roll is arranged to transfer the current collector to the coating roll. The system includes at least one roll with bare film carrier material and one roll with coated film carrier material. The roll with the bare film carrier material is arranged to apply a carrier material to a first portion of the current collector before the current collector is coated with the electrode material.The roller with the coated film carrier material is mounted such that the carrier material is applied to the first part of the current collector after the current collector has been coated with the electrode material. The carrier material is applied to a thickness selected such that the stress is evenly distributed across the bare and coated sections of the current collector during a calendering process, forming a pressed electrode with improved edge quality.

[0006] In addition to one or more of the features described herein, in some embodiments, one or more collection rolls are arranged to recover the backing material after the calendering process. In some embodiments, the one or more collection rolls comprise an upper backing material take-up roll mounted to recover the backing material from the top surface of the pressed electrode. In some embodiments, the one or more collection rolls further comprise a lower backing material take-up roll mounted to recover the backing material from the bottom surface of the pressed electrode.

[0007] In some embodiments, the carrier material comprises one or more of polyimide, a polymer, a silicone-based adhesive, polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), and metal film.

[0008] According to the invention, the system comprises a comma roll separated from the coating roll by a gap. The gap determines the amount of electrode material with which the current collector is coated.

[0009] In another exemplary embodiment, a method for manufacturing electrodes with improved edge quality is provided. The method includes providing a current collector, applying a carrier material to a first portion of the current collector, coating the current collector and the carrier material with an electrode material, calendering the current collector, the carrier material, and the electrode material, and removing the carrier material from the first portion of the current collector.

[0010] In some embodiments, the support material is applied to a thickness selected to distribute the calendering stress evenly between the bare and coated portions of the current collector.

[0011] According to the invention, the method comprises applying additional support material over the first section of the current collector after calendering. The additional support material is applied directly to the electrode material.

[0012] In some embodiments, the carrier material comprises one or more of polyimides, a polymer, a silicone-based adhesive, PTFE, PVC, and a metal film.

[0013] In some embodiments, applying the carrier material to the first portion of the current collector comprises providing a roller with bare film carrier material mounted to apply the carrier material to the first portion of the current collector before coating the current collector with the electrode material.

[0014] In some embodiments, coating the current collector and the support material with the electrode material comprises providing a supply of active material comprising the electrode material and providing a coating roller connected to the supply of active material. The coating roller is positioned to coat the current collector with the electrode material.

[0015] In yet another exemplary embodiment, a method for manufacturing electrodes with improved edge quality may include providing a current collector, coating a first portion of the current collector with an electrode material, applying a carrier material to a second portion of the current collector, calendering the current collector, the carrier material, and the electrode material, and removing the carrier material from the second portion of the current collector.

[0016] In some embodiments, the support material is applied with a thickness selected such that the calendering stress is evenly distributed across the first and second portions of the current collector.

[0017] In some embodiments, the carrier material comprises one or more of polyimide, a polymer, a silicone-based adhesive, PTFE, PVC, and a metal film.

[0018] In some embodiments, applying the carrier material to the second portion of the current collector comprises providing a roller with coated film carrier material arranged to apply the carrier material to the second portion of the current collector after the first portion of the current collector has been coated with the electrode material.

[0019] In some embodiments, coating the first portion of the current collector with the electrode material comprises providing a supply of active material comprising the electrode material and providing a coating roller connected to the supply of active material. The coating roller is positioned to coat the current collector with the electrode material.

[0020] In some embodiments, removing the carrier material comprises providing an upper carrier material take-up roll mounted to recover the carrier material from the top surface of the current collector.

[0021] In some embodiments, removing the carrier material further comprises providing a lower carrier material take-up roll mounted to recover the carrier material from a lower surface of the current collector.

[0022] The foregoing features and advantages, as well as other features and advantages of the disclosure, will be readily apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Further features, advantages and details are listed only as examples in the following detailed description, which refers to the drawings. Fig. 1 is a vehicle configured according to one or more embodiments; Fig. 2 is an exemplary embodiment of an electrode coating system according to one or more embodiments; Fig. 3 is an exemplary embodiment of an electrode calendering system according to one or more embodiments; Fig. 4 is a process flow for manufacturing electrodes with improved edge quality according to one or more embodiments; Fig. 5 is another process flow for manufacturing electrodes with improved edge quality according to one or more embodiments; Fig. 6 is a flowchart according to one or more embodiments; and Fig. 7 is a flowchart according to one or more embodiments. DETAILED DESCRIPTION

[0024] The following description is merely exemplary and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, like or corresponding parts and features are designated by corresponding reference characters.

[0025] Electrodes often include current collectors to complement or otherwise enhance the electrical energy storage features of the integrated end device (e.g., a battery). A current collector is typically formed from a film of conductive material (e.g., aluminum film) to which an electrode active material is attached. To improve the quality of the interfacial bond between the film of electrode active material and the current collector, the combined film and current collector are processed in a pressure laminator. Therefore, the fabrication of an electrode typically involves fabricating a film of electrode active material and laminating this film to a current collector (called calendering).

[0026] Calendering can be broadly defined as the compression of a dried electrode (usually resulting from the coating and drying of an electrode slurry) to reduce its porosity, improve particle contact, and increase energy or power density. Conventional calendering processes have been used to improve various aspects of battery technology, for example, by providing higher specific conductivity, larger contact areas, and lower contact resistance in the electrode. However, several challenges exist when optimizing the calendering process.

[0027] One such challenge, for example, is that calendering electrodes (e.g., cathodes) onto current collector substrates (e.g., film substrates such as aluminum, stainless steel, and titanium) results in a wrinkling defect when lower porosity is desired. Wrinkling occurs at the interface between the coated sections of the current collector (i.e., the sections with pressed electrode layers) and the uncoated sections (i.e., the bare sections of the current collector) and is due to the different material properties of the electrode and substrate materials. These defects worsen as the resulting porosity decreases, meaning that electrodes with relatively low porosity are inherently more affected by wrinkling.

[0028] While there are several approaches to reducing wrinkling, each carries some trade-off. For example, the naive approach is to increase the target porosity, which leads to a proportional reduction in wrinkling but at the expense of lower electrode conductivity. Another approach is to completely cover the substrate so that there is no interface where wrinkling defects can occur. The trade-off is that the bare film portions of the current collector (i.e., the portions not covered by the electrode active material) are ideal for use as battery terminals, and simply removing the bare film portions reduces battery efficiency.

[0029] This disclosure introduces a novel electrode calendering system and method for fabricating electrodes with improved edge quality. Instead of increasing porosity targets or removing (or reducing) the bare film portions of an electrode, the electrode calendering process described herein utilizes support materials to evenly distribute stress during the calendering process. In some embodiments, a layer of support material is applied directly to the bare portions of a current collector. The support materials can be applied before or after coating portions of the current collector with electrode active material (i.e., the electrode coating or film).The support materials can be designed to have a thickness that mimics the layer thickness of the electrode film pressed onto the current collector substrate, which depends on the strength properties of the current collector. The current collector, the electrode coating, and the support materials are then subjected to the calendering process, where the presence of the layer of support material ensures that the stress exerted on the bare film portions of the current collector is the same as the stress exerted by the electrode coating on the coated portion of the current collector. After calendering, the layer of support material can be removed. In this way, wrinkling defects can be reduced and edge quality can be increased without compromising the porosity targets and / or the surface finish of the bare film.In some embodiments, after the calendering process, a second layer of carrier material is applied over the first layer of carrier material to support the first layer during removal of the carrier material and to further improve edge quality.

[0030] The use of support materials in fabricating electrodes according to one or more embodiments offers several technical advantages over previous designs. In particular, the modified manufacturing process described herein can be used to fabricate electrodes without (or with greatly reduced) wrinkling defects. Batteries constructed from electrodes without wrinkles offer a number of improved battery properties, as wrinkles can compromise the integrity of the electrodes (e.g., wrinkles can lead to poor adhesion between the coated electrode film and the current collector, resulting in areas of relatively weak attachment that are prone to delamination or detachment), increase electrical resistance (wrinkles can create gaps or areas of reduced contact between the electrode material and the current collector, which can impede electron flow),Increase degradation and shorten cycle life (electrodes with wrinkles may be subjected to 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 instabilities (wrinkles can trap electrolyte and hinder heat dissipation, creating local hotspots that can degrade the electrolyte), and reduce capacity and energy density (wrinkle defects can lead to uneven thickness distribution across the electrode surface, and these unevennesses can result in lower active material utilization, lower capacity, and lower energy density in the battery). Other benefits are possible. For example, while a roller press can be redesigned,To enable the application and removal of carrier material, aspects of the present disclosure can be used to modify existing roll presses to reduce wrinkle defects without the need to redesign comma rolls, coating rolls, and / or counter rolls.

[0031] A vehicle according to an exemplary embodiment is generally shown at 100 in Fig. 1. The vehicle 100 is illustrated in the form of an automobile having a body 102. The body 102 includes a passenger compartment 104 in which a steering wheel, front seats, and rear passenger seats (not separately indicated) are disposed. Disposed within the body 102 are a number of components, including, for example, an electric motor 106 (shown by projection under the front hood). The electric motor 106 is shown for illustration and discussion only. It should be understood that the configuration, location, size, arrangement, etc., of the electric motor 106 are not intended to be particularly limited, and that all such configurations (including configurations having multiple motors) are within the intended scope of this disclosure.

[0032] The electric motor 106 is powered by a battery pack 108 (shown by projection near the rear of the vehicle 100). The battery pack 108 is shown for illustration and discussion only. It should be understood that the configuration, location, size, arrangement, etc., of the battery pack 108 are not intended to be particularly limited, and that all such configurations (including split configurations) fall within the intended scope of this disclosure. Although the present disclosure is primarily discussed in the context of a battery pack 108 configured for the electric motor 106 of the vehicle 100, the aspects described herein may similarly be incorporated into any system (vehicle, building, or other) having one or more energy storage systems (e.g.,one or more battery packs or modules), and all such configurations and applications fall within the contemplated scope of this disclosure.

[0033] As explained in more detail below, the battery pack 108 includes one or more cells with low porosity electrodes and improved edge quality (not separately shown). In some embodiments, an electrode coating system is modified such that support materials are applied to portions of a current collector to evenly distribute the voltage during a calendering process (see Fig. 2). In some embodiments, an electrode calendering system is modified such that the support materials are removed after calendering (see Fig. 3). In some embodiments, the electrode coating system and the electrode calendering system together form an electrode assembly system. In some embodiments, the support materials are applied prior to coating the current collector and the support materials with electrode material (see Fig. 4). In some embodiments, the carrier materials are applied after coating the current collector with electrode material (see Fig. 5).

[0034] Fig. 2 illustrates an exemplary embodiment of an electrode coating system 200 according to one or more embodiments. As shown in Fig. 2, the electrode coating system 200 may include a comma roll 202, a coating roll 204, and a counter roll 206 configured and arranged as shown. The electrode coating system 200 is shown in a so-called reverse comma coating configuration for discussion and illustration only. Other coating methods are possible, such as direct comma coating and slot die coating, and all such configurations are within the intended scope of this disclosure.

[0035] In some embodiments, the electrode coating system 200 includes a base plate 208 upon which a film 210 is disposed, and a supply of active material 212 (also referred to as an electrode slurry and / or electrode material source). The electrode material in the supply of active material 212 is not intended to be particularly limited, but may, for example, include various cathode or anode materials (depending on the requirements of a particular application), such as: E.g. 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 manganese rich (LMR), lithium manganese oxide (LMO), graphite, silicon, silicon graphite composites, tin, tin oxide (SnO2), lithium titanate (Li4Ti5O 12, LTO), sulfur and lithium-sulfur compounds (Li-S), lithium metal (Li), and / or lithium alloys such as lithium antimony (Li-Sb), lithium aluminum (Li-Al), and lithium germanium (Li-Ge). The active material supply 212 may include, for example, a liquid supply dam (as shown), a semi-solid extrusion source, and / or a solid supply, depending on the particular process.

[0036] In some embodiments, the film 210 is wetted by the supply of active material 212 as it passes through a gap 214 between the comma roll 202 and the coating roll 204. In some embodiments, the gap 214 can be adjusted by adjusting (e.g., hydraulically or otherwise) the relative positions of one or both of the comma rolls 202 and the coating roll 204. The gap 214 controls the amount of material from the supply of active material 212 that can be loaded onto the film 210.

[0037] In some embodiments, the electrode coating system 200 includes a cleaning blade 216 aligned with the coating roller 204. The cleaning blade 216 may be equipped with an edge to remove residue from the coating roller 204.

[0038] In some embodiments, the electrode coating system 200 includes a current collector 218 (also referred to as a web or bare film) that is passed between the backing roll 206 and the coating roll 204 and into contact with the coated film 213 (i.e., the electrode material). In this way, the electrode material can be continuously applied to a surface of the current collector 218 to form a coated current collector 220 (also referred to as a coated web). In some embodiments, the current collector 218 is a sheet of conductive metal, e.g., aluminum film, stainless steel, and titanium film, to which the coated film 210 is attached. Other materials are possible, such as semi-metals (e.g., tin, graphite) and alloys of metals and / or semi-metals.

[0039] In some embodiments, the coated current collector 220 may be directly supplied to a calendering system (e.g., via a direct feed, not separately shown). In some embodiments, the coated current collector 220 may be indirectly supplied to a calendering system (e.g., wound into a coated electrode roll before being supplied to the calendering system, see Fig. 3).

[0040] How to continue in Fig. 2, the electrode coating system 200 may include one or both rolls 222 with bare film carrier material and a roll 224 with coated film carrier material.

[0041] In some embodiments, the bare film carrier roll 222 is configured to deposit and / or otherwise form a carrier material 226 on the current collector 218 before it is coated with the electrode material (i.e., on the bare film). This configuration is described in Fig. 4 is explained in more detail.

[0042] In some embodiments, the bare film carrier roll 224 is configured to deposit and / or otherwise form a carrier material 226 on the current collector 218 after being coated with the electrode material (i.e., on the coated film). This configuration is described in Fig. 5 is explained in more detail.

[0043] Alternatively or additionally, the carrier material 226 may be applied (formed and / or applied) directly to a bare film substrate without (or in addition to) direct integration into the electrode coating system 200 (not separately shown). For example, the carrier material 226 may be formed onto the bare film upon receipt of the film roll and / or applied directly adjacent to the coating prior to calendering (i.e., after forming the coated current collector 220 but prior to calendering, as in Fig. 3). In some embodiments, the carrier material 226 can be directly integrated into the film development and / or coating process using additive manufacturing, e.g., 3D printing. In some embodiments, the carrier material 226 can be printed directly onto a film substrate, for example, when wound into a roll. Advantageously, this configuration decouples the application of the carrier material 226 from the electrode coating system 200, thus enabling unique electrode coating patterns for various applications. In some embodiments, the carrier material 226 is applied using a cryogenic spray to ensure adhesion to the bare film (e.g., in aluminum applications). In some embodiments, the carrier material 226 is printed from a source of powder material.

[0044] In some embodiments, the coated current collector 220 is flipped over and passed through the electrode coating system 200 a second time to coat the backside of the current collector 218 (i.e., a double-sided configuration, not separately shown). The backside of the current collector 218 may be coated, and the carrier material may be applied in a similar manner as previously described with respect to the first pass through the electrode coating system 200.

[0045] Fig. 3 illustrates an exemplary embodiment of an electrode calendering system 300 according to one or more embodiments. As shown in Fig. 3, the electrode calendering system 300 may include a coated electrode roll 302. In some embodiments, the coated current collector 220 is wound onto the coated electrode roll 302 after a coating process (see Fig. 2). In some embodiments, the coated current collector 220 is unwound from the coated electrode roll 302 and fed to a roll press 304 for calendering. In some embodiments, the coated current collector 220 may also be fed directly to the roll press 304.

[0046] In some embodiments, the roller press 304 includes an upper roller 306 and a lower roller 308 arranged to apply pressure to the coated current collector 220. This process, known as calendering, is intended to improve the density, uniformity, and overall performance of the resulting pressed electrode 310 (i.e., the pressed current collector 218, the coated film 210, and the carrier material 226) by compressing and densifying the electrode material on a portion of the current collector 218.

[0047] The upper roller 306 and the lower roller 308 can be made of a durable material, such as steel, and with precision surfaces (e.g., with tolerances of less than 10 microns) to ensure even pressure distribution. In some embodiments, the upper roller 306 is positioned vertically above the lower roller 308, and a gap G can be adjusted by moving (e.g., hydraulically) the upper roller 306 and the lower roller 308, or both rollers, to control the amount of applied pressure.

[0048] In some embodiments, the roll press 304 includes several control parameters, such as a roll temperature (top and / or bottom), a calendering pressure, a gap distance, and a line speed. In some embodiments, the roll temperature is 50 degrees Celsius, the pressure is 4.5 MPa, and the line speed is 0.5 meters per minute, although other calendering configurations are contemplated within the intended scope of this disclosure. In some embodiments, the gap G can be adjusted to the desired thickness of the pressed electrode 310.

[0049] When the upper roller 306 and / or the lower roller 308 apply pressure, the coated current collector 220 is compressed. This improves the density of the pressed electrode 310, removes voids and air pockets, and improves contact between the electrode material (i.e., the coated film 210) and the current collector 218. The calendering process also results in a reduction in the thickness of the coated current collector 220 because the pressed electrode 310 flattens under the pressure of the rollers.

[0050] In some embodiments, the presence of the backing material 226 ensures that the stress applied to the bare film portions of the current collector 218 is the same as the stress applied by the coated film 210 to the coated portions of the current collector 218. In some embodiments, the thickness of the backing material 226 is selected for a particular application to ensure uniform stress distribution. It should be noted that the thickness required to achieve uniform stress distribution varies depending on the loading (e.g., milligrams per square centimeter) and density of the electrode material, the material chosen for the current collector 218, and the target thickness of the pressed electrode 310.

[0051] How to continue in Fig. As shown in Figure 3, the electrode calendering system 300 may include a take-up roll 312. In some embodiments, the pressed electrode 310 is gathered into one or more rolls using the take-up roll 312.

[0052] In some embodiments, the electrode calendering system 300 may include an upper carrier material take-up roll 314 and / or a lower carrier material take-up roll 316 (also referred to as collection rolls), depending on whether a particular application utilizes a single-sided or double-sided coating configuration (see Fig. 2). In some embodiments, the upper carrier material take-up roll 314 is configured to reclaim the carrier material 226 disposed and / or formed on the upper surface of the pressed electrode 310. In some embodiments, the lower carrier material take-up roll 316 is configured to reclaim the carrier material 226 disposed and / or formed on the underside of the pressed electrode 310. In some embodiments, the upper carrier material take-up roll 314 and the lower carrier material take-up roll 316 are configured to engage the carrier material 226 prior to the reclaiming of the pressed electrode 310 by the take-up roll 312.

[0053] Fig. 4 illustrates a process flow 400 for manufacturing electrodes with improved edge quality according to one or more embodiments. The process flow 400 describes a first manufacturing method in which a carrier material is applied to a current collector before it is coated with an electrode material. The process 400 may be used as part of an electrode coating (see Fig. 2) and calendering process (see Fig. 3) be carried out.

[0054] The process 400 begins with step 402, in which a current collector 218 is obtained for coating / calendering. In some embodiments, the current collector 218 is provided as a sheet or film that is passed between a backing roll 206 and a coating roll 204 to, as previously described with reference to Fig. 2 described, to come into contact with the electrode material.

[0055] In step 404, a backing material 226 is applied to a surface of the current collector 218. In some embodiments, the backing material 226 is applied to portions of the current collector 218 that will constitute a bare film in the final, pressed electrode (i.e., the portions not covered with electrode material). In some embodiments, the backing material 226 is formed with a thickness selected such that the subsequent calendering stresses (see step 408) are the same (or substantially the same within the tool limits) in both the bare and coated portions of the current collector 218.

[0056] In some embodiments, the carrier material 226 is applied and / or formed as a single layer of material. In some embodiments, the carrier material 226 is applied and / or formed as two or more stacked layers of material. In some embodiments, additional layers of the carrier material 226 can be stacked to achieve a desired thickness.

[0057] In some embodiments, the carrier material 226 may include an adhesive component and / or a protective layer. In some embodiments, the carrier material 226 comprises a material selected for thermal stability. For example, the carrier material 226 may include one or more materials that are thermally stable up to 150 degrees Celsius. In some embodiments, the carrier material 226 comprises an adhesive that can adhere to the current collector 218 but is also removable without residue. In some embodiments, the carrier material 226 comprises a material selected to be resistant to the slurry chemical composition (e.g., NMP, water, etc.) of a particular application. In some embodiments, the carrier material 226 comprises a material designed for storage stability (e.g., retains its properties for 6 months, 1 year, etc.).In some embodiments, the support material 226 comprises a material that is impermeable to the electrode slurry. In some embodiments, the support material 226 comprises a material that is compressible at the calendering pressures applicable to a particular application. For example, in scenarios where a pressure of 4.5 MPa is required to reduce an electrode thickness by 100 micrometers, the support material 226 may comprise materials with a Young's modulus of 45 GPa or greater. Example materials include, but are not limited to, polyimide tapes and / or composites, flexible polymers, silicone-based adhesives, polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), adhesive-coated PVC supports, and metal film.

[0058] In step 406, the current collector 218 and the carrier material 226 are coated with electrode material (e.g., the coated film 210). The current collector 218 may be coated with a coating system (e.g., with the coating system described in Fig. 2 described electrode coating system 200).

[0059] In step 408, the current collector 218, the carrier material 226 and the coated film 210 are calendered using a calendering system (e.g., the one described in Fig. 3) to produce a pressed electrode 310. Advantageously, the carrier material 226 serves to more evenly distribute the calendering stresses during this process, resulting in reduced wrinkling effects and improved edge quality of the pressed electrode 310.

[0060] In step 410, the carrier material 226 (and portions of the pressed electrode 310 formed thereon) is removed to expose a bare film portion of the current collector 218. The carrier material 226 may be removed using collection rollers (e.g., the upper carrier material take-up roller 314 and / or the lower carrier material take-up roller 316), as previously described.

[0061] Optionally, the process 400 may include a step 412 inserted between step 408 and step 410. In step 412, an additional layer of the carrier material 226 is applied to portions of the pressed electrode 310 over the initial, first layer of the carrier material 226. In this embodiment, the process 400 continues with step 410, in which both the first layer and the additional layer of the carrier material 226 are removed. Advantageously, the additional layer of the carrier material 226 serves to further assist in the removal of portions of the pressed electrode 310.

[0062] Fig. 5 illustrates a process flow 500 for manufacturing electrodes with improved edge quality according to one or more embodiments. The process flow 500 describes a second manufacturing method in which a carrier material is applied to a current collector after coating with an electrode material. The process 500 may be used as part of an electrode coating (see Fig. 2) and calendering process (see Fig. 3) be carried out.

[0063] The process 500 begins with step 502, in which a current collector 218 is obtained for coating / calendering. In some embodiments, the current collector 218 is provided as a sheet or film that is passed between a backing roll 206 and a coating roll 204 to, as previously described with reference to Fig. 2 described, to come into contact with the electrode material.

[0064] In step 504, a portion of the current collector 218 is coated with electrode material (e.g., the coated film 210). The current collector 218 may be coated with a coating system (e.g., the coating system described in Fig. 2 described electrode coating system 200).

[0065] In step 506, a carrier material 226 is applied to a bare surface of the current collector 218 (i.e., to the portions not coated in step 504). In some embodiments, the carrier material 226 is formed to a thickness selected such that the subsequent calendering stresses (see step 508) are the same (or substantially the same within the tool limits) in both the bare and coated portions of the current collector 218. The carrier material 226 may be applied and / or formed as a single layer of material or as two or more stacked layers of material and may include an adhesive component and / or a protective layer, as previously described.

[0066] In step 508, the current collector 218, the carrier material 226 and the coated film 210 are calendered using a calendering system (e.g., the one described in Fig. 3) to produce a pressed electrode 310. Advantageously, the carrier material 226 serves to more evenly distribute the calendering stresses during this process, resulting in reduced wrinkling effects and improved edge quality of the pressed electrode 310.

[0067] In step 510, the carrier material 226 (and portions of the pressed electrode 310 formed thereon) is removed to expose a bare film portion of the current collector 218. The carrier material 226 may be removed using collection rollers (e.g., the upper carrier material take-up roller 314 and / or the lower carrier material take-up roller 316), as previously described.

[0068] With reference now to Fig. 6, a flowchart 600 for manufacturing electrodes with improved edge quality according to one embodiment is generally illustrated. The flowchart 600 is described with reference to Fig. 1-5 and can contain further Fig. 6 steps not shown. The Fig. Although the blocks shown in Figure 6 are presented in a specific order, they can be rearranged, subdivided and / or combined.

[0069] In block 602, the method includes providing a current collector.

[0070] In block 604, the method includes applying a carrier material to a first portion of the current collector. In some embodiments, the carrier material is applied to a thickness selected to evenly distribute the calendering stress between the bare and coated portions of the current collector. In some embodiments, the carrier material comprises one or more of polyimide, a polymer, a silicone-based adhesive, PTFE, PVC, and a metal film.

[0071] In some embodiments, applying the carrier material to the first portion of the current collector comprises providing a roller with bare film carrier material mounted to apply the carrier material to the first portion of the current collector before coating the current collector with the electrode material.

[0072] In block 606, the method includes coating the current collector and the support material with an electrode material. In some embodiments, coating the current collector and the support material with the electrode material includes providing a liquid storage dam comprising the electrode material and providing a coating roller connected to the liquid storage dam. The coating roller is positioned to coat the current collector with the electrode material.

[0073] In block 608, the method includes calendering the current collector, the support material, and the electrode material.

[0074] The process involves applying additional support material over the first section of the current collector after calendering. The additional support material is applied directly to the electrode material.

[0075] In block 610, the method includes removing the carrier material from the first portion of the current collector.

[0076] With reference now to Fig. 7, a flowchart 700 for manufacturing electrodes with improved edge quality according to one embodiment is generally illustrated. The flowchart 700 is described with reference to Fig. 1-5 and can contain further Fig. 7 steps not shown. The steps in Fig. Although the blocks shown in Figure 7 are presented in a specific order, they can be rearranged, subdivided and / or combined.

[0077] In block 702, the method includes providing a current collector.

[0078] In block 704, the method includes coating a first portion of the current collector with an electrode material. In some embodiments, coating the first portion of the current collector with the electrode material includes providing a liquid storage dam comprising the electrode material and providing a coating roller connected to the liquid storage dam. The coating roller is positioned to coat the current collector with the electrode material.

[0079] In block 706, the method includes applying a support material to a second portion of the current collector. In some embodiments, the support material is applied to a thickness selected to evenly distribute the calendering stress across the first and second portions of the current collector. In some embodiments, the support material comprises one or more of polyimide, a polymer, a silicone-based adhesive, PTFE, PVC, and a metal film.

[0080] In some embodiments, applying the carrier material to the second portion of the current collector comprises providing a roller with coated film carrier material arranged to apply the carrier material to the second portion of the current collector after the first portion of the current collector has been coated with the electrode material.

[0081] In block 708, the method includes calendering the current collector, the support material, and the electrode material.

[0082] At block 710, the method includes removing the carrier material from the second portion of the current collector. In some embodiments, removing the carrier material includes providing an upper carrier material take-up roll mounted to reclaim the carrier material from the top surface of the current collector. In some embodiments, removing the carrier material further includes providing a lower carrier material take-up roll mounted to reclaim the carrier material from a bottom surface of the current collector.

[0083] The terms "a" and "an" do not imply a limitation of quantity, but denote the presence of at least one of the mentioned items. The term "or" means "and / or" unless the context clearly indicates otherwise. When reference is made throughout this specification to "an aspect," this means that a particular element (e.g., a feature, structure, step, or property) described in connection with the aspect is encompassed in at least one of the aspects described herein and may or may not be present in other aspects. It is also understood that the described elements in the various aspects may be combined in any suitable manner.

[0084] When an element such as a layer, film, region, or substrate is described as lying "on" another element, it may lie directly on top of the other element, or there may be intervening elements. In contrast, when an element is described as lying "directly on" another element, there are no intervening elements.

[0085] Unless otherwise indicated herein, all examination standards are the most recent standard in effect on the filing date of this application or, if priority is claimed, the filing date of the earliest priority application in which the examination standard appears.

[0086] Unless otherwise defined, 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.

[0087] Although the above disclosure has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes may be made and equivalent elements may be substituted without departing from its scope. Furthermore, many changes may be made to adapt a particular situation or material to the teachings of the disclosure without departing from its essential scope. Therefore, the present disclosure is not intended to be limited to the particular embodiments, but is intended to include all embodiments falling within its scope.

Claims

[1] System (200) for producing electrodes (310) with improved edge quality, the system (200) comprising: a liquid storage dam comprising an electrode material (212); a coating roller (204) connected to the liquid storage dam, the coating roller (204) arranged to coat a current collector (218) with the electrode material (212); a counter roller (206) arranged to transfer the current collector (218) to the coating roller (204); and at least one of a roller (222) with bare film carrier material (226) and a roller (224) with coated film carrier material (226); wherein the roller (222) with the bare film carrier material (226) is arranged such that a carrier material (226) is applied to a first part of the current collector (218) before the current collector (218) is coated with the electrode material (212); wherein the roller (224) with the coated film carrier material (226) is mounted such that the carrier material (226) is applied to the first portion of the current collector (218) after the current collector (218) has been coated with the electrode material (212); and wherein the carrier material (226) is applied in a thickness selected such that the stress is evenly distributed over bare portions and coated portions of the current collector (218) during a calendering process, thereby forming a pressed electrode (310) with improved edge quality; characterized bythat the system (200) comprises a comma roll (202) separated from the coating roll (204) by a gap (218), the gap (218) defining an amount of the electrode material (212) applied to the current collector (218). [2] The system (200) of claim 1, further comprising one or more collection rolls (314, 316) arranged to recover the carrier material (226) after the calendering process. [3] The system (200) of claim 2, wherein the one or more collection rolls (314, 316) comprise an upper take-up roll (318) for the carrier material (226) mounted to recover the carrier material (226) from an upper surface of the pressed electrode (310). [4] The system (200) of claim 3, wherein the one or more collection rolls (314, 316) further comprise a lower take-up roll (316) for the carrier material (226) mounted to recover the carrier material (226) from a lower surface of the pressed electrode (310). [5] The system (200) of claim 1, wherein the carrier material (226) comprises one or more of polyimide, a polymer, a silicone-based adhesive, polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), and metal film. [6] Method comprising: Providing a current collector (218); Applying a carrier material (226) to a first portion of the current collector (218); Coating the current collector (218) and the carrier material (226) with an electrode material (212); Calendering the current collector (218), the carrier material (226) and the electrode material (212); and Removing the carrier material (226) from the first section of the current collector (218), wherein after calendering additional carrier material (226) is applied to the first section of the current collector (218), characterized by that the additional carrier material (226) is applied directly to the electrode material (212). [7] The method of claim 6, wherein the carrier material (226) is applied in a thickness selected such that the calendering stress is evenly distributed over bare and coated portions of the current collector.

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