Method and apparatus for separating active material from current collector
By separating the active materials and current collectors in lithium-ion battery cells through heating and mechanical loading, the problems of resource waste and environmental pollution in existing technologies are solved, and the efficient separation and recycling of active materials and current collectors are achieved.
Patent Information
- Application Number
- CN202480020228.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-03-30
- Filing Date
- 2024-03-21
- Publication Date
- 2025-11-14
Smart Images
Figure CN120958150A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method and apparatus for separating active materials from a current collector. Background Technology
[0002] In the field of energy storage units, especially battery units, particularly lithium-ion battery units, cylindrical, prismatic, and pouch battery units are primarily known. Battery units for storing electrical energy play a central role in the so-called electric vehicle sector, whether in pure electric or hybrid vehicles. Cylindrical lithium-ion battery units may have an electrode roll in which electrodes, including a separator, are spirally wound around a core in a separator-anode-separator-cathode configuration.
[0003] Here, the electrode may be composed of a current collector, on which, especially on both sides, a mixture of active material, binder and conductive additive is coated.
[0004] In the subsequent Kalandern rolling process, the coated electrodes are conveyed between two rollers that apply mechanical pressure to the electrodes, compressing them during transport and thereby increasing their mass density. This higher mass density typically allows for higher energy density in battery cells using these electrodes.
[0005] At the end of the battery cell's lifespan or when waste is generated during the manufacturing process, it is desirable to recycle the individual components of the battery cell from both economic and ecological perspectives. This particularly involves the electrodes. For reuse, materials need to be separated, especially the active materials from the current collector. Mechanical methods can be used here, in which the coated current collector is pulverized into smaller fractions, which are then sorted. Summary of the Invention
[0006] The objective of this disclosure is to enable improved separation of active materials from current collectors, so that the active materials and / or current collectors can be reused.
[0007] A solution to this task has been achieved based on the teachings of the independent claims. Various embodiments and extensions of the invention are the subject of the dependent claims.
[0008] The first aspect of the solution relates to a method for separating active material from a current collector (particularly a current collector foil), particularly a computer-implemented method, wherein the current collector is coated on at least one side with a mixture of materials consisting of an active material and a binder, the method comprising the following automated steps: (i) heating the coated current collector to the softening temperature of the binder; (ii) mechanically loading the heated coated current collector, thereby at least partially breaking down the active material, thus achieving separation of the active material from the current collector.
[0009] The terms “comprising,” “including,” “encompassing,” “having,” “having,” “with,” or any other variation thereof, as may be used herein, are intended to cover non-exclusive inclusion. For example, a method or apparatus that includes or has a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such a method or apparatus.
[0010] Furthermore, unless the opposite is explicitly stated, "or" refers to an inclusive "or," not an exclusive "or." For example, condition A or B is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and both A and B are true (or exist).
[0011] The term “one” as used herein should be understood as “one or more”. The terms “another” and “another” and any other variations thereof should be understood as “at least one more”.
[0012] The term “multiple” as used here should be understood as “two or more”.
[0013] The terms "configured to" or "set to" to perform a specific function (and its variations) should be understood here as meaning that the corresponding device is already in a constructed or set state capable of performing that function, or at least is adjustable—that is, configurable—so that it can perform that function after being appropriately set. Here, configuration can be achieved, for example, by appropriately setting process parameters or switches or the like to activate or deactivate a function or setting. In particular, the device may have multiple predetermined configuration or operating modes, such that the configuration can be achieved by selecting one of these configuration or operating modes.
[0014] The term "active material" here should be understood as, in particular, a material that is electrochemically active and suitable for coating electrodes of an electrode roll in a battery cell, wherein ions (especially lithium ions) can be intercalated. Here, the active material for the cathode may particularly include NMC, NCA, NCMA, LCO, LFP, LMFP, LMO, LNMO, or other materials. The active material for the anode may particularly include graphite, SiOx, SiC, Si, or other materials.
[0015] The term "current collector" here should be understood, in particular, as a component made of a conductive material (especially copper or aluminum). It is used to conduct current between two geometrically separated points.
[0016] The term "adhesive" here should be understood, in particular, as an element used to bond or adhere active materials to a current collector. Adhesives may include, in particular, PVDF, PTFE, CMC, SBR, LiPAA, or PAA.
[0017] The method described in the first aspect enables the effective separation of the active material from the current collector. By heating the current collector coated with the active material to the softening temperature of the binder, the adhesive effect of the binder can be weakened. Then, through mechanical loading, the active material can be broken down. Due to the brittleness of the coating itself and the ductility of the foil, the active material can be separated from the current collector. Thus, the active material and the current collector can be collected and reused separately.
[0018] The preferred embodiments of the method are described below. Unless explicitly excluded or technically impossible, these embodiments may be combined with each other in any way, and may also be combined with other aspects described.
[0019] In some embodiments, the method further includes: (i) heating at least a first roller to the softening temperature of the adhesive; and (ii) conveying the current collector to be coated through the first roller, thereby heating the current collector by the heated first roller. This allows for effective heating of a longer current collector web via the first roller. Furthermore, during the manufacturing process of the current collector, a roller assembly can be used for rolling. This roller assembly can now be modified slightly for the heating step, thus enabling a low-cost method.
[0020] In some embodiments, the method further includes: (i) heating the second roller to the softening temperature of the adhesive, wherein the first and second rollers are arranged substantially parallel and spaced apart in relation to their respective axes of rotation, particularly the spacing being approximately equivalent to the thickness of the current collector to be coated; and (ii) conveying the current collector to be coated between the first and second rollers, thereby heating the current collector to be coated by the heated first and second rollers. This allows for rapid and uniform heating of the current collector to be coated, as it is heated from both sides as it is conveyed between the first and second rollers. During this heating process, mechanical contact between the current collector to the rollers is advantageous to facilitate efficient heat transfer via thermal conduction. Specifically, the distance between the first and second rollers can be set such that the first and second rollers apply a predetermined pressure to the current collector to be coated, thereby introducing stress into the coating. This allows for subsequent separation of the coating from the current collector. Accordingly, roller assemblies for rolling can be used in this heating process, and advantageously adapted in terms of the spacing between the first and second rollers.
[0021] In some embodiments, the first and / or second rollers comprise a thermally conductive material, particularly copper. This allows for particularly good and efficient heat transfer from the first and / or second rollers to the coated current collector.
[0022] In some embodiments, the current collector to be coated is heated to the decomposition temperature of the adhesive. This makes it easier for the coating to separate from the current collector. Furthermore, it prevents subsequent separation of the adhesive from the active material.
[0023] In some embodiments, the heated coated current collector is mechanically loaded by at least one third roller, the surface of which is constructed with protrusions, particularly tapered pointed protrusions. The third and fourth rollers are arranged substantially parallel and spaced apart in relation to their respective axes of rotation, with the spacing being less than the thickness of the coated current collector and greater than the thickness of the uncoated current collector. Mechanical loading is performed through the protruding surfaces as the heated coated current collector is conveyed between the third and fourth rollers, thereby at least partially breaking down the active material. By using at least one roller for mechanical loading, continuously coated current collectors (e.g., current collectors wound on rollers) can be continuously conveyed. Combined with the previous conveying of the coated current collector through the first roller, the method step of effectively and continuously applying the next mechanical loading step to the heated coated current collector can be achieved.
[0024] In some embodiments, the first and / or second and / or third and / or fourth rollers are driven by a motor (particularly an electric motor), thereby rotating the respective rollers about their axis of rotation. Driving at least one roller by a motor allows for effective control of the delivery of the coated current collector. In particular, the rotational speed and thus the delivery speed can be controlled by the motor. A relatively low speed is advantageous for achieving efficient heat transfer via the first and / or second rollers.
[0025] The second aspect of the solution relates to an apparatus for separating active material from a current collector, wherein the current collector is coated on at least one side with a mixture of materials consisting of an active material and a binder, the apparatus being configured to perform the method of any one of the preceding claims.
[0026] In some embodiments, the device includes: (i) a first roller and a second roller, the first roller and the second roller being arranged substantially parallel and spaced apart in relation to their respective axes of rotation, and adapted to convey the current collector to be coated between the first roller and the second roller; and (ii) a heating device configured to heat the first roller and the second roller to the softening temperature of the adhesive, thereby heating the current collector to the softening temperature as it is conveyed between the first roller and the second roller.
[0027] In some embodiments, the device includes a third roller and a fourth roller arranged substantially parallel and spaced apart in relation to their respective axes of rotation. At least one of the third and fourth rollers includes a raised surface structure such that when the coated current collector is conveyed between the third and fourth rollers, the coated current collector is mechanically loaded through the raised surface structure, causing at least partial breakage of the active material and achieving separation of the active material from the current collector.
[0028] The third aspect of the solution relates to a computer program containing instructions that, when executed on the device described in the second aspect, cause the device to perform the method described in the first aspect.
[0029] The features and advantages described in the first aspect of the solution also apply to the other aspects described. Attached Figure Description
[0030] Other advantages, features, and applicability will become apparent from the following description of the preferred embodiments in conjunction with the accompanying drawings.
[0031] In the attached image:
[0032] Figure 1 A flowchart illustrating a preferred embodiment of a method for separating active materials from a current collector is schematically shown; and
[0033] Figure 2 An apparatus according to one embodiment is illustrated schematically.
[0034] In the accompanying drawings, the same or corresponding elements are always referred to by the same reference numerals. Detailed Implementation
[0035] Figure 1 A flowchart illustrating a preferred embodiment of a method for separating active material from current collector 210 is shown schematically, wherein current collector 210 is coated on at least one side with a mixture of materials consisting of active material 210 and binder.
[0036] In the first step 110 of the method, the current collector 210 to be coated is heated to the softening temperature of the adhesive. The adhesive may in particular be polyvinylidene fluoride (PVDF), which has a softening temperature of about 120°C.
[0037] In another step 120 of the method, the heated coated current collector 210 is mechanically loaded, thereby at least partially breaking down the active material and separating the active material from the current collector 210.
[0038] Figure 2 A device 200 according to one embodiment is illustrated schematically.
[0039] The device 200 has a housing 230, within which a first roller 250 and a second roller 255 are arranged, positioned opposite each other and spaced apart along their axes of rotation. A heating device 240 is also arranged within the housing 230. The heating device 240 can heat both the first roller 250 and the second roller 255, as well as the interior space of the housing 230.
[0040] The housing 230 also has an input opening and an output opening, which are at approximately the same height relative to the drawing plane.
[0041] During operation, electrode 205 is conveyed through the input opening between the first roller 250 and the second roller 255 in the conveying direction. The conveying direction is schematically shown by arrows. Electrode 205 has a current collector 210 (particularly made of copper or aluminum) and coatings 220 located on the upper and lower sides of the current collector 210, respectively. Coating 220 consists of active materials, binders, and additives, or conductive additives. Conductive additives may in particular contain carbon black or carbon fibers. Coating 220 can be applied as a slurry to both sides of the current collector 210.
[0042] When the coated current collector 210 is conveyed between the first roller 250 and the second roller 255, the coating comes into mechanical contact with the first roller 250 and the second roller 255, thereby transferring heat to the coating through thermal conduction. Here, the heating device 240 is configured to heat the first roller 250 and the second roller 255 to the softening temperature of the adhesive. Thus, the coating is heated to the softening temperature as it is conveyed between the first roller 250 and the second roller 255. Therefore, it is advantageous that the first roller 250 and the second roller 255 comprise a material with good thermal conductivity, such as copper.
[0043] By heating the coating 220, the adhesive's bonding effect will be weakened.
[0044] The binder may contain polyvinylidene fluoride (PVDF), which has a softening temperature of approximately 120°C and a decomposition start temperature of 350°C. Temperature control of the heating device 240 is achieved through a control device (not shown) integrated into the heating device 240.
[0045] The device also includes a third roller 260 and a fourth roller 265, which are located after the first roller 250 and the second roller 255 in the conveying direction and are disposed outside the housing 230. The third roller 260 and the fourth roller 265 are arranged opposite each other and spaced apart in their axis of rotation. The third roller 260 and the fourth roller 265 each have a surface structure that mechanically loads the coated current collector 210 as it is conveyed between the third roller 260 and the fourth roller 265, thereby breaking up the heated coating 220 and allowing it to be separated from the current collector 210. To improve the breaking up effect of the heated coating 220, the surface structure has prominent protrusions, especially tapered pointed protrusions, such as pyramidal, conical, or toothed protrusions. Here, the spacing between the third roller 260 and the fourth roller 265 is advantageously chosen such that, during conveying, the protrusions extend substantially to the surface of the uncoated current collector 210.
[0046] Through crushing, the active material is broken down into smaller parts, while the current collector 210 is broken down into larger parts. Thus, the active material can be easily separated from the electrode material and reused.
[0047] Rollers 250, 255, 260, and 265 are each cylindrical in shape and are driven by electric motors (not shown here). The rotation speed of the rollers can also be controlled by the electric motors.
[0048] This equipment is advantageously applicable when the coated current collector 210 is constructed as a strip material, because the coated current collector 210 can be efficiently transported and processed by a roll-to-roll process.
[0049] Although at least one exemplary embodiment has been described above, it should be noted that numerous variations exist. It should also be noted that the described exemplary embodiments are merely non-limiting examples and are not intended to limit the scope, applicability, or configuration of the devices and methods described herein. Rather, the foregoing description will provide guidance to those skilled in the art in implementing at least one exemplary embodiment, and it should be understood that various changes may be made to the function and arrangement of the elements described in the exemplary embodiments without departing from the subject matter defined by the appended claims and their legal equivalents.
[0050] List of reference numerals
[0051] 100 is a flowchart illustrating a preferred embodiment of the method.
[0052] 110 Heating the coated current collector
[0053] 120 Apply mechanical loading to the coated current collector.
[0054] 200 devices
[0055] 205 electrode
[0056] 210 Current collector
[0057] 220 coating
[0058] 230 housing
[0059] 240 Heating device
[0060] 250, 255 First Roller and Second Roller
[0061] 260, 265, third and fourth rolls
Claims
1. A method for separating active materials from a current collector (210), wherein, The current collector (210) is coated on at least one side with a material mixture (220) consisting of the active material and the binder, and the method includes the following automated steps: The current collector (210) to be coated is heated to the softening temperature of the adhesive; Mechanical loading is applied to the heated coated current collector (210), thereby at least partially breaking down the active material and separating the active material from the current collector (210).
2. The method according to claim 1, wherein, The method also includes: At least one first roller (250) is heated to the softening temperature of the adhesive; The current collector (210) to be coated is conveyed through the first roller (250), thereby heating the current collector (210) by the heated first roller (250).
3. The method according to claim 2, wherein, The method also includes: The second roller (255) is heated to the softening temperature of the adhesive, wherein the first roller (250) and the second roller (255) are arranged substantially parallel to each other and spaced apart in relation to their respective axes of rotation; The current collector (210) to be coated is conveyed between the first roller (250) and the second roller (255), thereby heating the current collector (210) by the heated first roller (250) and the heated second roller (255).
4. The method according to claim 2 or 3, wherein, The first roller (250) and / or the second roller (255) have thermally conductive materials.
5. The method according to any one of the preceding claims, wherein, The coated current collector is heated until it reaches the decomposition temperature of the adhesive.
6. The method according to any one of the preceding claims, wherein, The heated coated current collector (210) is mechanically loaded by at least one third roller (260) with protrusions formed on its surface. The third roller (260) and the fourth roller (265) are arranged substantially parallel to each other at a distance from each other in terms of their respective axes of rotation. When the heated coated current collector (210) is conveyed between the third roller (260) and the fourth roller (265), it is mechanically loaded by the surface with protrusions, and thereby at least partially breaks down the active material.
7. The method according to any one of claims 2 to 6, wherein, The first roller (250) and / or the second roller (255) and / or the third roller (260) and / or the fourth roller (265) are driven by a motor, thereby causing the respective rollers (250, 255, 260, 265) to rotate about their axis of rotation.
8. An apparatus for separating active materials from a current collector, wherein, The current collector is coated on at least one side with a mixture of materials consisting of the active material and the binder, and the device is configured to perform the method according to any one of the preceding claims.
9. The device according to claim 8, wherein, The device includes: A first roller (250) and a second roller (255) are arranged substantially parallel to each other at a distance from each other in terms of their respective axes of rotation, and are adapted to convey the current collector (210) to be coated through between the first roller (255) and the second roller (260). A heating device (240) is configured to heat the first roller (250) and the second roller (255) to the softening temperature of the adhesive, thereby heating the coated current collector (210) to the softening temperature as it is conveyed between the first roller (250) and the second roller (255).
10. The device according to claim 8 or 9, wherein, The device includes a third roller (260) and a fourth roller (265) arranged substantially parallel to each other at a distance from each other in terms of their respective axes of rotation. At least one of the third roller (260) and the fourth roller (265) includes a raised surface structure such that when the coated current collector (210) is conveyed between the third roller (260) and the fourth roller (265), the coated current collector (210) is mechanically loaded by the raised surface structure, such that the active material is at least partially broken up, thereby separating the active material from the current collector.
11. Computer programs, in which, The computer program includes instructions that, when executed on a device according to any one of claims 8 to 10, cause the device to perform the method according to any one of claims 1 to 7.