RECOVERY OF CONTAMINANT FREE BATTERY MATERIALS

Abstract

A method for producing clean black mass, anode or cathode for subsequent recycling is provided, the method comprising subjecting an intact battery to a shredding process to produce an aggregate, wherein the smallest particle generated is between 2.5 percent and 40 percent of original battery size. Also provided is a shredder for minimizing aggregation of whole batteries, the shredder comprising a shaft defining a longitudinal axis and a latitudinal axis; and a plurality of teeth disposed on said knives which fit on said shaft at an angle to the latitudinal axis selected from 15 degrees and 45 degrees, wherein the teeth have a first proximal end integrally molded to the shaft and a second free distal end.

Claims

1. A method for direct recycling a whole battery, the method comprising subjecting the battery to a shredding process to produce particles, wherein the smallest particle generated is between 2.5 percent and 40 percent of original battery size.

2. The method as recited in claim 1 wherein the method occurs in the absence of ambient air.

3. The method as recited in claim 1 wherein the method occurs at a pressure between 0 and −30 psig.

4. The method as recited in claim 1 wherein the method occurs below the freezing point of electrolyte present in the intact battery.

5. The method as recited in claim 1 wherein the particles comprise current collector foil laminated with electrode powder.

6. The method as recited in claim 1 wherein the shredding process utilizes teeth rotating at between 5 rpm and 400 rpm.

7. The method as recited in claim 6 wherein the teeth are positioned on a periphery of a rotating knife and each of said teeth define an edge arranged at between 0 degrees and 45 degrees relative to an arc formed by the periphery.

8. The method as recited in claim 7 wherein the teeth are arranged at 0 degrees relative to an arc formed by the periphery and the knife rotates about a single shaft.

9. The method as recited in claim 1 wherein particles have an aspect ratio between 2:1 and 1:1 with a single pass of the whole battery through the shredding process.

10. The method as recited in claim 1 wherein the battery defines a configuration selected from the group consisting of pouch, cylindrical, prismatic and combinations thereof.

11. A shredder for minimizing aggregation of whole batteries, the shredder comprising the following: a) a shaft defining a longitudinal axis and a latitudinal axis; and b) a plurality of teeth disposed on knives which fit on said shaft at an angle to the latitudinal axis selected from 0 degrees and 45 degrees, wherein the teeth have a first proximal end integrally molded to the shaft and a second free distal end.

12. The shredder as recited in claim 11 wherein the free distal end defines a hook.

13. The shredder as recited in claim 11 wherein the shaft and teeth define a knife and the distance between teeth is similar to the width of the knife.

14. The shredder as recited in claim 13 wherein the aspect ratio of the distance between the teeth to the width of the knife is near 1.

15. The shredder as recited in claim 11 wherein the shredder defines a single shaft system.

16. The shredder as recited in claim 11 wherein the shredder defines a multiple shaft system.

17. The shredder as recited in claim 11 wherein the distance between the teeth edges ranges from ⅛ inches to 12 inches.

18. The shredder as recited in claim 11 wherein the teeth define a pattern selected from the group consisting of running, chevron, staggered, and combinations thereof.

Description

BRIEF DESCRIPTION OF DRAWING

[0030] The invention together with the above and other objects and advantages will be best understood from the following detailed description of the preferred embodiment of the invention shown in the accompanying drawings, wherein:

[0031] FIG. 1A is an elevational view of a tooth configuration for a direct recycling shredder, in accordance with features of the present invention;

[0032] FIG. 1B is a schematic diagram showing the ratio of teeth width to teeth distance, in accordance with features of the present invention.

[0033] FIG. 2 is a detailed view of a knife cross section, in accordance with features of the present invention;

[0034] FIG. 3 is a schematic diagram of the invented shredder knives engaging with battery material in accordance with features of the present invention.

[0035] FIG. 4A is an isometric view of two sets of coaxially arranged knives rotating toward each other, each set supported on its own shaft 24; in accordance with features of the present invention;

[0036] FIG. 4B is a side view of one set of coaxially arranged knives depicted in FIG. 4A having a running pattern, in accordance with features of the present invention;

[0037] FIG. 4C is an isometric view of two sets of coaxially arranged knives rotating toward each other in a chevron pattern;

[0038] FIG. 4D is a side view of one set of coaxially arranged knives depicted in FIG. 4C having a chevron pattern;

[0039] FIG. 5 is a schematic diagram of the invented shredder with optional air locks for maintaining an inert atmosphere;

[0040] FIG. 6A is a photograph of batteries size reduced using state of the art size reduction equipment;

[0041] FIG. 6B is a photograph of black mass from size reduced batteries using state of the art size reduction equipment;

[0042] FIG. 6C is a photograph of batteries processed using the invented shredder configuration, in accordance with features of the present invention; and

[0043] FIG. 6D is a photograph of black mass from shredded batteries using the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0044] The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings.

[0045] All numeric values are herein assumed to be modified by the term “about”, whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (e.g., having the same function or result). In many instances, the terms “about” may include numbers that are rounded to the nearest significant figure.

[0046] The recitation of numerical ranges by endpoints includes all numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0047] The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention.

[0048] As used herein, an element or step recited in the singular and preceded with the word “a” or “an” should be understood as not excluding plural said elements or steps, unless such exclusion is explicitly stated. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.

[0049] Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property.

[0050] The process described in this patent focuses on a method for recycling lithium-ion batteries called direct recycling. Direct recycling involves maintaining the original chemical structure and process value of battery components by recovering, regenerating, and reusing them directly. By retaining the value of original battery components, a higher revenue potential from the products is possible. The inventors found that maintaining larger aggregate sizes during battery material deconstruction reduces impurity content of recyclable powders generated thereby.

[0051] This invention relates to a device and method for the production of clean black mass material from batteries to be used in various recycling process types such as pyrometallurgical, hydrometallurgical, and direct recycling processes.

[0052] The invention provides a method and system for recovering contaminant free battery materials to be used as feedstock material in recycling processes. It enables safely shredding batteries/cells in a manner that produces relatively large (ideally ½″ to 4″ square or rectangular) pieces of cathode, anode, or mixture laminates (active material still attached to the collector foil). The invented knife configuration allows the electrode to remain laminated or otherwise adhered to the foil after a single shredding pass with minimal amount of the electrode broken off the foil. This minimizes fines generation, which is an inherent problem with state of the art shredding processes.

[0053] As stated supra, the invention utilizes a single pass, low-speed process for generating large size (e.g., greater than 500 microns) particles, that process selected from the group consisting of shredding, punching, water-cutting, and combinations thereof. Punching involves a specifically sized die (i.e., would work best for prismatic or pouch cell designs) and a press. A substrate, in this case a battery, is place below the press and pressure is applied to cut and generate consistently sized pieces of material where the shape corresponds to the design of the die used for punching.

[0054] Water cutting also yields consistently sized pieces of batteries for recycling. In this method, a high-pressure water jet is mechanically controlled to intricately cut material with specified dimensions through pantographs or more recently, CNC-type controls

[0055] When a shredder is utilized, the invented process does not use shredder energy to generate excessive amounts of small particles (e.g., less than 500 microns in diameter where this fraction constitutes less than 5 weight percent of the shredder reside) or remove electrode powder from the foil comprising the electrodes. Rather, the shredder's energy is used to simply cut up whole batteries and battery cells into relatively larger pieces that are uniform in size. These large pieces can then be cleaned of the fines contamination and the clean anode and cathode powders can be delaminated from the foils in any number of ways that do not generate contamination providing a clean black mass.

[0056] Specifically, a shredder and process for using the shredder has been perfected, with the following aspects of the shredder varied to increase efficiency and reduce fine particle contamination: [0057] Number of shafts; [0058] Knife configuration; [0059] Number and geometry of teeth; [0060] Presence of screen to select shred size; and [0061] Multiple shredder stages.

[0062] This invention comprises cutting up the battery as little as possible, while focusing on liberating the various electrode laminates. The objective is to isolate as much cathode and anode laminate material as possible with zero or nominal fine particle generation. Indeed, chemistries such as lithium cobalt oxide (LCO), lithium nickel cobalt aluminum oxide (NCA), lithium nickel manganese cobalt oxide (NMC), or lithium manganese oxide (LMO) may comprise more than 30 to 50 percent of a battery's weight. For example, in some configurations, nickel comprises 15-50 percent of the black mass harvested, cobalt 5-40 percent, and lithium 5-10 percent. In the case of NMC622, nickel comprises 24 weight percent of the black mass harvested, cobalt 8 weight percent, and lithium 5 weight percent.

[0063] The laminates are then treated with several steps (e.g. delamination and/or thermal or chemical or mechanical binder removal) to recover the clean powders from the laminates.

[0064] No matter what size cells are inputted, the invented process and method generates the same output size of aggregate. This maximizes energy efficiencies. The invention provides a means for generating the most preferred size of shredded recyclable bulk. Specifically, the invention generates shredded sizes ranging from 2.5 percent to 40 percent of original battery size. Pieces from large pouch cell processing are generated near the lower end. Cylindrical cell pieces are generated near the higher end of the range.

[0065] The inventors found that the number of shafts (1-vs 2-vs 4-shaft), knife configuration, and the number and geometry of knife teeth can have a significant effect on the size and distribution of shredded material and amount of fine particles produced. Any number of shafts in the shredder can be effective in this invented process. Single shaft systems optimize liberation of the laminates. Multi-shaft systems, and particularly the 4-shaft system has benefits in consistent feeding of the material. Testing was performed on 2-shaft systems, so depicted in FIG. 3.

[0066] The RPM rate of a dual shaft shear shredder embodying the aforementioned teeth configurations can be from 5 to 60 RPM, where a range of 10-40 rpm is preferred. A single shaft system may also be used where the RPM rate can be from 5-400 RPM with a range of 25-200 RPM preferred.

[0067] A salient feature of the invention is the incorporation of shredder teeth wherein the teeth are positioned such that the distance between teeth is similar to and defined by the width of the knife, thus yielding material that is relatively square or rectangular in shape such that the aspect ratio is preferably less than 4 to 1, and most preferably an aspect ratio at approximately 1 to 1 (e.g., a square configuration). Square shreds flow better than long ribbon-like pieces, the latter of which wind around each other and possibly in various equipment downstream (especially a stirring tank which may be used for electrolyte removal). This is why the invention targets an aspect ratio near 1, give or take a 10 to 25 percent variation relative to the x and y axis of the square.

[0068] The improved design provides a range of contaminates between 0 to 1 mole percent (where 0-0.2 mole percent is the preferred range) using the formula LiNi.sub.1-x-yMn.sub.xCO.sub.yO.sub.2. Contaminants in the black mass can include, but are not limited to, copper, aluminum, iron, silicon, and stainless steel.

[0069] FIG. 1A depicts the invented shredding knife configuration designated as numeral 10. As shown, the knife is disk-shaped having a first surface 12 and a second surface 14, and a periphery. The surfaces 12 and 14 are generally flat parallel with each other, and laterally facing so as to face way from each other. The configuration defines a generally circular cross section having a center region forming an aperture 16.

[0070] The periphery of the aperture is formed to slidably receive or otherwise accommodate a spinning axle or shaft (not shown). As such, the periphery may be hexagonal, square, triangular, ovoid or circular in shape, the later utilizing a keyway or other means to prevent independent rotation of the knife about the axle.

[0071] The periphery of the knife terminates in circumferentially arranged blades 18 having an edge extending parallel to the axle, and therefore extending orthogonal to the surfaces, 12, 14. While the edge 20 is depicted as continuous and straight, other edges are suitable, such as serrated, concave, convex, or sine wave in shape.

[0072] As depicted in FIGS. 1A and 1B, the knife width is similar to the distance between the knife tips 17. This facilitates the generation of aggregate having an aspect ratio at or close to 1:1. Specifically, FIG. 1B is a schematic diagram showing the ratio of teeth width to teeth distance. The shaft and teeth are shown defining a knife with the distance between teeth X similar to the width Y of the knife. In an embodiment of the invention, the aspect ratio of the distance between the teeth to the width of the knife is near 1.

[0073] FIG. 2 is a detailed view of the teeth configuration of the invented shredder knife. Generally, the teeth are symmetrically spaced around the periphery 17 of the knife. Teeth length “L” is defined by a radial projection from the disk. Length ranges from ⅛ inches to 12 inches, and preferably 0.25 inches and 1.5 inches.

[0074] Angle of projection of the teeth may vary from 15 to 45 degrees relative to a line defined by a point p1 on the knife periphery and a point p2 at the center of the aperture 16 of the knife. A plurality of teeth are similarly arranged given a plurality of similarly arranged lines. FIGS. 1 and 2 depict eleven teeth, such that two perpendicularly arranged lines define the angles of the teeth, and the teeth are spaced generally symmetrically from each other in approximately a 33 degree arc relative to the periphery 17 of the disk. However, greater or fewer teeth may be provided. For example, if three teeth are provided, the teeth may be symmetrically arranged at approximately a 120 degree arc relative to each other along the periphery 17.

[0075] FIG. 3 is a view of a plurality of invented shredder knives 10 engaging with and decompiling a pouch cell within a hopper 22. Two knives are shown mounted on two different axles or shafts 24 which are parallel to each other. The knives may overlap each other so that their laterally facing surfaces oppose each other. The knives rotate toward each other so as to pinch the cell between the teeth of the two knives. In the event that there is a blockage in the knives and they stop rotating toward each, the rotation direction can be reversed to free the blockage.

[0076] Various teeth patterns are utilized, including but not limited to staggered, chevron, running, and combinations thereof. The views in FIG. 4 show a plurality of knives arranged along a shaft or multiple shafts such that the knives are stacked along side each other such that all of the knives are coaxially arranged with each other along longitudinally extending regions of the shaft 24. The shaft has a circumference that is complementary to the center aperture of each of the knives such that the knives are slidably receive along the shaft. This results in the knives being rigidly but reversibly affixed in relation to the shaft such that the knives do not rotate independently of the shaft. This feature provides a means for arranging the periphery of the knives relative to each other to define different slicing patterns.

[0077] FIGS. 4A and 4B show knife tips arranged in a running pattern, as expressed by the arrows. FIG. 4A is an isometric view of two knives rotating toward each other, each knife supported on its own shaft 24. The teeth rotating path is helical in shape. FIG. 4B is a side view of one of the knives.

[0078] FIGS. 4C and 4D illustrate knife tips configured in a chevron (“v” shaped) pattern. A staggered pattern is a yet a third configuration that involves a more randomized repeating of pattern choice.

[0079] Operation Detail

[0080] As depicted in FIG. 3, end of life batteries are fed into the hopper 22 of the shredder using a bulk transport means such as a conveyor belt. The batteries are positioned in the hopper belt such that one layer of cells is fed into the length of the hopper 22 at a time. This is aimed to prevent stacking of batteries in the shredder and contact of batteries with one another which can lead to short circuiting and possibly thermal runaway events (e.g., heat increase within a cell that can cause venting of organic solvent, fire, and explosions). In an embodiment of the process, the resulting feed scheme should include a continuous stream of singular batteries/modules/cells so as to maintain a consistent shredding position resulting in an organized, single pass (once through the shredder knives) size reduction process.

[0081] One way to ameliorate the fire hazard is to perform the shredding operations in an inert atmosphere (e.g., the absence of ambient air) such as under nitrogen, or even more cost effectively, under water or other fluid such as nitrogen, argon, carbon dioxide, or combinations thereof.

[0082] Preferably, one layer of batteries passes through the shredder before another is introduced. The feed rate of the conveyor is controlled to coincide with the rate at which batteries pass through the shredder blades.

[0083] Battery feeding may take place under ambient temperature and pressure. Cells fed into the shredder may be at room temperature or as low as the temperature of liquid nitrogen. Lowering the temperature of the battery will essentially deactivate it (particularly by freezing the electrolyte and preventing the transfer of ions within the battery) and render it safe for shredding. Battery temperatures of between 25° C. and minus 200° C. and preferably between −20° C. and minus 175° C. provides safe procedures. The inventors envision loading batteries which have a loading temperature of at least as low as minus 60° C., and preferably as low as minus 125° C.

[0084] The shredding may also take place under inert atmosphere to reduce the amount of oxygen present and reduce the risk for fires or explosions. A myriad of liquids or gases, nonreactive to battery components can be utilized to establish an inert atmosphere within the shredder. Such fluids may include nitrogen, argon, carbon dioxide, water, diethylene glycol diethyl carbonate, dimethyl carbonate, and combinations thereof. Gases may flow directly through the shredder. Conversely, “air” locks 30 can be incorporated above and below the shredding area to reduce the amount of gas consumed, as shown in FIG. 5. However, to facilitate smooth operation, the “air” locks may have to be purged each time they are opened and new material is introduced, unless a positive flow out of the locks is maintained during loading.

[0085] The shredded battery material, specifically the anode and cathode laminate shred that has yet to be delaminated, can be processed in any manner necessary to achieve clean black mass. Example processes include screening fines away from the laminates, rinsing electrolyte and contaminant particles off of the laminates, delaminating the active powders from the collector foils using thermal, chemical or mechanical means, and finally screening and collection of the black mass from the collector foils.

[0086] FIG. 6A is a photograph of batteries size reduced using state of the art size reduction equipment while FIG. 6B is a photograph of the black mass produced from size reduced batteries using state of the art equipment. The size reduced batteries using state of the art equipment show pieces of battery components (e.g., plastics, metals, casing, electrodes) with a wide range of sizes which can make downstream processing and separation challenging. In addition, the process mechanically removes the electrodes from foil which makes it challenging to remove any impurities from the black mass after the size reduction process. It is clear that the black mass in FIG. 6B is contaminated with fine particles of the battery components.

[0087] FIG. 6C is a photograph of batteries processed using the invented shredder configuration, in accordance with features of the present invention. FIG. 6D is a photograph of black mass produced from shredded batteries using the present invention. The size reduced batteries using the invented shredder configuration show battery components that are similar in size with a relatively small amount of fine particle contamination. Once the fine particles are sieved or rinsed from the shredded material, the black mass in FIG. 6D is produced which is visually and analytically higher purity than that from the state of the art.

Example

[0088] An embodiment of the system and method includes the following experimental parameters: [0089] Shredding knife 4.7 inches in diameter and 11 teeth; [0090] 2-shaft shear shredder operating at 30 RPM; [0091] Running Knife pattern; [0092] 40 Ah commercial pouch cells approximately 10″ wide×10″ long×W thick.

[0093] The results from the above example included that almost 90 weight percent of pieces were above 2.8 mm in size. After sieving fines particles from the shredder battery material, processed black mass was greater than 99 percent pure. Much of the fines were removed with sieving.

[0094] The inventors have observed that where no shredder screen is used in the shredder, less contaminated fines are produced. As such, a screen-less hopper optimizes the generation of particles larger than 500 microns.

[0095] The material of the shredder and knives maybe made of any rigid material, such as steel, stainless steel, titanium, or diamond tipped knives.

[0096] Fire suppression can be used in and around the shredder in case of fire.

[0097] Any fines generated from shredding may be removed through screening, rinsing, etc. This optimizes the generation of such a clean material to delaminate, further improving purity of the black mass,

[0098] It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. While the dimensions and types of materials described herein are intended to define the parameters of the invention, they are by no means limiting, but are instead exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112, sixth paragraph, unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.

[0099] As will be understood by one skilled in the art, for any and all purposes, particularly in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as “up to,” “at least,” “greater than,” “less than,” “more than” and the like include the number recited and refer to ranges which can be subsequently broken down into subranges as discussed above. In the same manner, all ratios disclosed herein also include all subratios falling within the broader ratio.

[0100] One skilled in the art will also readily recognize that where members are grouped together in a common manner, such as in a Markush group, the present invention encompasses not only the entire group listed as a whole, but each member of the group individually and all possible subgroups of the main group. Accordingly, for all purposes, the present invention encompasses not only the main group, but also the main group absent one or more of the group members. The present invention also envisages the explicit exclusion of one or more of any of the group members in the claimed invention.