Method for stiffening wire mesh current collector of electrode of battery cell

Abstract

The invention relates to a stiffening method for a wire mesh current collector of an electrode of a battery cell. A method of manufacturing a current collector for an electrode of a battery cell includes providing a wire mesh current collector including wires having a diameter and forming grid nodes; and rolling the wire mesh current collector by using a first roller and a second roller, wherein the first roller and the second roller are spaced by a predetermined gap, and the predetermined gap is less than twice the wire diameter of the wire mesh current collector.

Description

Technical Field

[0001] The present disclosure relates to current collectors for electrodes of battery cells, and more particularly to methods of stiffening wire mesh current collectors for battery cells. Background Art

[0002] The information provided in this section is for the purpose of generally introducing the background of the present disclosure. No admission is made, either explicitly or implicitly, that the work of the presently named inventors described in this section is prior art to the present disclosure, nor is it admitted that the work is prior art to the present disclosure, as described in this section, which may not otherwise be identified as prior art at the time of filing.

[0003] Electric vehicles (EVs), such as battery electric vehicles (BEVs), hybrid electric vehicles, and / or fuel cell vehicles, include one or more motors and a battery system, which includes one or more battery cells, modules, and / or packs. A battery control module is used to control the charging and / or discharging of the battery system during charging and / or driving. EV manufacturers are committed to improving power density to increase the range of EVs. Summary of the invention

[0004] A method for manufacturing a current collector for an electrode of a battery cell includes providing a wire mesh current collector, which includes a wire having a certain diameter and forming grid nodes; and rolling the wire mesh current collector using a first roller and a second roller, wherein the first roller and the second roller are separated by a predetermined gap. The predetermined gap is less than 2 times the wire diameter of the wire mesh current collector.

[0005] In other features, the predetermined gap is greater than or equal to 1 times the wire diameter of the wire mesh current collector. The wire diameter is 4 μm to 100 μm. The wire of the wire mesh current collector is made of one or more materials selected from copper, stainless steel, brass, bronze, zinc and aluminum. The predetermined gap is greater than or equal to 1 times to less than or equal to 1.5 times the wire diameter of the wire mesh current collector.

[0006] In other features, the method includes disposing an anode active material layer adjacent to a wire mesh current collector. The method includes disposing a cathode active material layer adjacent to a wire mesh current collector. The method includes coating the wire mesh current collector with a slurry comprising an anode active material. The method includes coating the wire mesh current collector with a slurry comprising a cathode active material.

[0007] A method for manufacturing a current collector for an electrode of a battery cell includes providing a wire mesh current collector including a wire having a certain diameter and forming a grid node; rolling the wire mesh current collector using a first roller and a second roller, wherein the first roller and the second roller are separated by a predetermined gap; and supplying current to the first roller and the second roller to heat the wire mesh current collector to achieve at least one of the following: fusing, bonding and welding the wire at the grid node. The predetermined gap is less than 2 times the wire diameter of the wire mesh current collector.

[0008] In other features, the predetermined gap is greater than or equal to the wire diameter of the wire mesh current collector. The wire diameter is 4 μm to 100 μm. The wire of the wire mesh current collector is made of one or more materials selected from copper, stainless steel, brass, bronze and aluminum. The predetermined gap is greater than or equal to 1.5 times to less than or equal to 2 times the wire diameter of the wire mesh current collector.

[0009] In other features, the method includes disposing an anode active material layer adjacent to a wire mesh current collector. The method includes disposing a cathode active material layer adjacent to a wire mesh current collector. The method includes coating the wire mesh current collector with a slurry comprising an anode active material. The method includes coating the wire mesh current collector with a slurry comprising a cathode active material.

[0010] In other features, the first roller and the second roller include a radial outer layer comprising a refractory metal. The refractory metal is selected from tungsten, molybdenum, and copper-tungsten alloys. The method includes coating the wire mesh current collector with one or more materials selected from tin (Sn), indium (In), bismuth (Bi), zinc (Zn), and combinations thereof before rolling.

[0011] The present invention discloses the following scheme:

[0012] Scheme 1. A method for manufacturing a current collector for an electrode of a battery cell, comprising:

[0013] Providing a wire mesh current collector comprising wires having a certain diameter and forming mesh nodes; and

[0014] The wire mesh current collector is rolled using a first roller and a second roller, wherein the first roller and the second roller are spaced apart by a predetermined gap,

[0015] The predetermined gap is less than 2 times the wire diameter of the wire mesh current collector.

[0016] Option 2. A method according to Option 1, wherein the predetermined gap is greater than or equal to 1 times the wire diameter of the wire mesh current collector.

[0017] Option 3. The method according to Option 1, wherein the wire has a diameter of 4 μm to 100 μm.

[0018] Option 4. A method according to Option 1, wherein the wires of the wire mesh current collector are made of one or more materials selected from copper, stainless steel, brass, bronze, zinc and aluminum.

[0019] Option 5. A method according to Option 1, wherein the predetermined gap is greater than or equal to 1 times and less than or equal to 1.5 times the wire diameter of the wire mesh current collector.

[0020] Option 6. The method according to Option 1 further includes arranging an anode active material layer adjacent to the wire mesh current collector.

[0021] Option 7. The method according to Option 1 further includes arranging a cathode active material layer adjacent to the wire mesh current collector.

[0022] Option 8. The method according to Option 1 further comprises coating the wire mesh current collector with a slurry containing an anode active material.

[0023] Option 9. The method according to Option 1 further comprises coating the wire mesh current collector with a slurry containing a cathode active material.

[0024] Solution 10. A method for manufacturing a current collector for an electrode of a battery cell, comprising:

[0025] Providing a wire mesh current collector, which includes wires having a certain diameter and forming grid nodes;

[0026] rolling the wire mesh current collector using a first roller and a second roller, wherein the first roller and the second roller are spaced apart by a predetermined gap; and

[0027] supplying electric current to the first roller and the second roller to heat the wire mesh current collector to achieve at least one of: fusing, bonding and welding wires at mesh nodes,

[0028] The predetermined gap is less than 2 times the wire diameter of the wire mesh current collector.

[0029] Scheme 11. The method according to Scheme 10, wherein:

[0030] The predetermined gap is greater than or equal to the wire diameter of the wire mesh current collector.

[0031] Option 12. The method according to Option 10, wherein the wire has a diameter of 4 μm to 100 μm.

[0032] Option 13. A method according to Option 10, wherein the wires of the wire mesh current collector are made of one or more materials selected from copper, stainless steel, brass, bronze and aluminum.

[0033] Option 14. A method according to Option 10, wherein the predetermined gap is greater than or equal to 1.5 times and less than or equal to 2 times the wire diameter of the wire mesh current collector.

[0034] Option 15. The method according to Option 10 further includes arranging an anode active material layer adjacent to the wire mesh current collector.

[0035] Option 16. The method according to Option 10 further includes arranging a cathode active material layer adjacent to the wire mesh current collector.

[0036] Option 17. The method according to Option 10 further comprises coating the wire mesh current collector with a slurry containing an anode active material.

[0037] Option 18. The method according to Option 10 further comprises coating the wire mesh current collector with a slurry containing a cathode active material.

[0038] Embodiment 19. The method according to embodiment 10, wherein:

[0039] The first roll and the second roll include a radially outer layer comprising a refractory metal, and

[0040] The refractory metal is selected from tungsten, molybdenum and copper-tungsten alloy.

[0041] Option 20. The method according to Option 10 further comprises coating the wire mesh current collector with one or more materials selected from tin (Sn), indium (In), bismuth (Bi), zinc (Zn) and combinations thereof before rolling.

[0042] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings.The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The present disclosure will be more fully understood from the detailed description and accompanying drawings, in which:

[0044] Figure 1 is a side cross-sectional view of one embodiment of a battery cell including an electrode having a reinforced and / or stiffened wire mesh current collector according to the present disclosure;

[0045] Figure 2A and 2B is a plan view illustrating a tensile test of a wire mesh current collector in two directions before reinforcement and / or stiffening;

[0046] Figure 3 It is a graphic Figure 2A and 2B Load vs. displacement graphs in two directions;

[0047] Figure 4 is a cross-sectional photograph of a wire mesh current collector prior to strengthening and / or stiffening;

[0048] Figure 5 Illustrate one embodiment of a method of strengthening and / or stiffening a wire mesh current collector using skin pass rolling according to the present disclosure;

[0049] Fig. 6A and 6B is a graph illustrating load vs. displacement to show the performance improvement after strengthening and / or stiffening of the wire mesh current collector;

[0050] Fig. 7A and 7B are photographs of embodiments of wires at mesh nodes before and after reinforcement and / or stiffening of a wire mesh current collector according to the present disclosure;

[0051] Figure 8 illustrates one embodiment of another method of roll resistance welding to strengthen and / or stiffen a wire mesh current collector according to the present disclosure; and

[0052] Fig. 9 , Fig. 10A and 10B is using Figure 8 Photographs of the wires at the mesh nodes before and after the method of reinforcing and / or stiffening the wire mesh current collector.

[0053] In the drawings, reference numerals may be repeated to designate similar and / or identical elements. DETAILED DESCRIPTION

[0054] Although battery cells according to the present disclosure are described herein in the context of electric vehicles, the battery cells may be used in stationary applications and / or other types of applications.

[0055] The battery cell includes an anode electrode, a cathode electrode and a separator arranged in a predetermined order in a housing. The anode electrode includes an anode active layer arranged on one or both sides of an anode current collector. The cathode electrode includes a cathode active layer arranged on one or both sides of a cathode current collector.

[0056] The anode current collector and the cathode current collector may include foil, wire mesh or expanded metal. For example, the wire mesh current collector may use wire made of copper, stainless steel, brass, bronze, aluminum, etc. (e.g., Cu-100 or SS-100). The wire mesh can be made of wire with a thickness of 4 μm to 100 μm (e.g., 30 μm). In some embodiments, the wire mesh has about 100 to 300 openings per square inch (e.g., 100). In some embodiments, the wire mesh has low strength, rigidity, and / or deformation resistance to make it difficult to operate during electrode manufacturing.

[0057] The present disclosure relates to methods for strengthening and / or stiffening a wire mesh current collector used in an anode electrode and / or a cathode electrode. In some embodiments, the wire mesh current collector can be arranged adjacent to an anode active layer or a cathode active layer (e.g., a lithium foil layer) to form an anode electrode or a cathode electrode. In other embodiments, a slurry including an anode active material or a cathode active material, a binder, a conductive additive, and / or a solvent can be used to apply the wire mesh current collector in a roll-to-roll process to create an anode electrode or a cathode electrode.

[0058] For example, the wire mesh can be used as a three-dimensional current collector (3DCC) in next-generation lithium metal batteries. Compared with typical foil-type anode current collectors, 3DCC (such as Cu (or SS) interwoven wire mesh) has shown benefits in the fabrication of ultra-wide lithium anodes (about 500+ mm) with improved cycling performance.

[0059] In some embodiments, the wire mesh current collector is made of 30 μm thick Cu (or SS) wire with an open area of ​​about 70%. The wire mesh current collector is lighter than the 6 μm foil current collector (such as Cu or SS). However, the wire mesh current collector is fragile and difficult to handle during the rolling lithium insertion process. The low rigidity of the wire mesh current collector is attributed to the fact that there is almost no or no bonding between the overlapping wires at the grid nodes.

[0060] In some embodiments, the wire mesh current collector according to the present disclosure is strengthened and / or stiffened by rolling (e.g., flat rolling) the wire mesh current collector to press the mesh nodes together so that the wires are locked in place at the mesh nodes. In other embodiments, the wire mesh current collector according to the present disclosure is strengthened and / or stiffened by passing the wire mesh current collector between rollers. The rollers are connected to a power source that supplies an electric current through the rollers and the wire mesh current collector to fuse, bond, and / or weld the wires of the wire mesh at the mesh nodes.

[0061] In some embodiments, the wires of the wire mesh current collector are pre-coated with a metal coating comprising a material having a melting point below 500° C. In some embodiments, the material comprises tin (Sn), indium (In), bismuth (Bi), alloys thereof, and / or combinations thereof.

[0062] Reference now Figure 1, the battery cell 10 includes cathode electrodes 20-1, 20-2, ..., and 20-C, where C is an integer greater than 1. The cathode electrode 20 includes a cathode active material layer 24 arranged on one side or both sides of a cathode current collector 26. The battery cell 10 includes anode electrodes 40-1, 40-2, ..., and 40-A, where A is an integer greater than 1. The anode electrode 40 includes an anode active material layer 42 arranged on one side or both sides of an anode current collector 46. The cathode electrode 20, the anode electrode 40, and the separator 32 are arranged in a predetermined order in the housing 50. For example, the separator 32 is arranged between the cathode electrode 20 and the anode electrode 40. The anode current collector 46 and / or the cathode current collector 26 include a wire mesh that has been reinforced and / or stiffened as described below.

[0063] Reference now Figures 2A to 4 , the anode current collector and / or the cathode current collector may include a wire mesh. Figure 2A and 2B , a tensile test of a wire mesh current collector 47 in two directions is shown before reinforcement and / or stiffening. Figure 2A In the embodiment, the load is at 0° or 90° relative to the wires of the wire mesh current collector 47. Figure 2B In the figure, the load is at 45° relative to the wires of the wire mesh current collector 47.

[0064] Reference now Figure 3 , curve diagram Figure 2A and 2B Load vs. displacement of a wire mesh current collector in two directions. The wire mesh exhibits anisotropy in its mechanical properties. Figure 2A When pulled in the middle direction, the stiffness is about 22N / mm and the peak load is about 8N. Figure 2B When pulled in the middle direction, the stiffness is extremely low ~0.06N / mm, and the peak load is about 1.5 to 2N. Figure 4 In Figure 1, the photo shows a cross section of a wire mesh current collector before reinforcement and / or stiffening. The mesh nodes are weak and the wires tend to slide against each other at these nodes, resulting in low stiffness in the 45° direction.

[0065] Reference now Figure 5 , shows a method 100 of strengthening and / or stiffening a wire mesh current collector 47 using skin pass rolling. The wire mesh current collector 47 is shown to include wires 70, 72 to form a mesh node 74. Wires 70 intersect wires 72 at 90°. In some embodiments, the wire mesh current collector has a thickness of 4 μm to 100 μm, although other thicknesses may be used.

[0066] The wire mesh current collector 47 is passed through a first predetermined gap defined between the outer surfaces of the rollers 120 and 122. In some embodiments, the predetermined gap is selected to compress the mesh nodes 74 rather than the individual wires 70, 72. In some embodiments, the first predetermined gap is greater than or equal to the wire diameter to less than the total thickness of the wire mesh (e.g., less than 2 times the diameter of the wires 70, 72). In some embodiments, the first predetermined gap is greater than or equal to the wire diameter to less than or equal to 1.5 times the diameter of the wires 70, 72. After passing through the rollers, the wires 70', 72' at the mesh nodes 74' of the wire mesh current collector 47' are mechanically connected due to the strong mechanical contact at the mesh nodes 74'.

[0067] Reference now Figures 6A to 7B , graphs and photos illustrate before temper rolling ( Fig. 6A and 6B 150) and after temper rolling ( Fig. 6A and 6B The load vs. displacement of the wire mesh current collector of 152). The strengthening and / or stiffening performance of the wire mesh current collector is improved after strengthening and / or stiffening. Compared with the wire mesh current collector 47, the strength of the wire mesh current collector 47' is as follows Fig. 6A is about twice as strong as shown in Figure 6B Shown in is about 7 times.

[0068] exist Fig. 7A and 7B , a photograph of an embodiment of wires at mesh nodes is shown before and after reinforcement and / or stiffening of the wire mesh current collector. Before rolling, wires 70, 72 are as shown in FIG. Fig. 7A In some embodiments, the wires 70', 72' are pressed together after rolling and mechanically connected at the grid nodes 74' without changing the dimensions of the wires 70', 72'.

[0069] Reference now Figure 8 , showing a method of strengthening and / or stiffening a wire mesh current collector using roll resistance welding. The wire mesh current collector 210 is shown to include wires 212, 214 to form a grid node 216. Wire 212 intersects wire 214 at approximately 90°. In some embodiments, the wire mesh current collector has a thickness of 4μm to 100μm, although other thicknesses may be used. The wire mesh current collector 210 is passed through rollers 220 and 222 that define a second predetermined gap. A power source 223 supplies current, such as DC or AC current, across rollers 220 and 222. In some embodiments, the feed rate is 5 to 30m / min. In some embodiments, the current is 2 to 4kA and the pressure is 3 to 20kg / cm 2 .

[0070] In some embodiments, the second predetermined gap is set to contact and / or compress the mesh nodes 216 rather than the individual wires 212, 214. As the wire mesh current collector passes through the rollers 220 and 222, the rollers 220 and 222 contact the wire mesh current collector and pass the current from the power source through the wire mesh current collector to resistively heat the wire mesh current collector 210 and fuse, bond and / or weld the mesh nodes 216 together. In some embodiments, the second predetermined gap is 1.5 to 2 times the diameter of the wires 212, 214. After passing through the rollers 220 and 222, the wires 70', 72' at the mesh nodes 74' of the wire mesh current collector 47' are fused, bonded and / or welded together.

[0071] In some embodiments, the wire mesh current collector 210 is pre-coated with a coating 219 to enhance the welding of the grid nodes 216 during the roll welding process. In some embodiments, the coating 219 comprises a metal having a melting temperature below 500° C. The current passing through the wire mesh melts the coating rather than the wire, and the wires can be fused together due to the sintering of the coating. In some embodiments, the coating 219 comprises one or more materials selected from tin (Sn), indium (In), bismuth (Bi), zinc (Zn), alloys thereof, and / or combinations thereof.

[0072] In some embodiments, rollers 220 and 222 include outer layers 224 and 226, respectively, comprising a refractory metal alloy. In some embodiments, for non-ferrous metal meshes (Cu, brass, bronze) having high electrical conductivity, the refractory metal alloy comprises a material selected from an alloy of copper (Cu) and tungsten (W), such as Tuffaloy (Cu-W), pure W, or pure molybdenum.

[0073] Reference now Figures 9 to 10B ,use Figure 8 Photograph of wires at mesh nodes after method of reinforcing and / or stiffening a wire mesh current collector.

[0074] The method of strengthening and / or stiffening the wire mesh current collector is simple and inexpensive. Strengthening and / or stiffening the wire mesh current collector enables wider electrodes. The wire mesh current collector may also have reduced resistance due to improved contact between the wires at the mesh nodes. The reduced resistance results in reduced heating of the battery cells and improves battery cell and / or electrode efficiency by reducing losses caused by resistance.

[0075] The above description is only exemplary and is absolutely not intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in various forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be limited thereto, because after studying the drawings, the specification and the following claims, other modifications will become apparent. It should be understood that one or more steps in the method may be implemented in different orders (or simultaneously) without changing the principles of the present disclosure. In addition, although each embodiment is described above as having certain features, any one or more features described in any embodiment of the present disclosure may be implemented in any other embodiment and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the embodiments are not mutually exclusive, and the mutual replacement of one or more embodiments is still within the scope of the present disclosure.

[0076] Various terms are used to describe the spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.), including "connected," "engaged," "coupled," "adjacent," "next to," "on top of," "on," "under," and "disposed." Unless explicitly described as "directly," when describing the relationship between a first element and a second element in the above disclosure, the relationship can be a direct relationship in which there are no other intervening elements between the first element and the second element, or an indirect relationship in which there are one or more intervening elements (spatially or functionally) between the first element and the second element. The phrase "at least one of A, B, and C" as used herein should be interpreted to mean a logical (A or B or C) using a non-exclusive logical OR, and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C."

[0077] In the drawings, the direction of the arrows, as shown by the arrows, generally shows the flow of information (such as data or instructions) that the illustration is concerned with. For example, when component A and component B exchange various information but the information sent from component A to component B is relevant to the illustration, the arrow may point from component A to component B. Such a one-way arrow does not mean that no other information is sent from component B to component A. In addition, for information transmitted from component A to component B, component B may send a request for the information or a receipt to component A.

Claims

1. A method for manufacturing a current collector for an electrode of a battery cell, comprising: Providing a wire mesh current collector, which includes wires having a certain diameter and forming grid nodes; and The wire mesh current collector is rolled using a first roller and a second roller, wherein the first roller and the second roller are spaced apart by a predetermined gap, The predetermined gap is less than 2 times the wire diameter of the wire mesh current collector. 2 . The method according to claim 1 , wherein the predetermined gap is greater than or equal to 1 times the wire diameter of the wire mesh current collector. The method according to claim 1 , wherein the wire has a diameter of 4 μm to 100 μm. 4 . The method according to claim 1 , wherein the wires of the wire mesh current collector are made of one or more materials selected from the group consisting of copper, stainless steel, brass, bronze, zinc and aluminum. 5 . The method according to claim 1 , wherein the predetermined gap is greater than or equal to 1 time and less than or equal to 1.5 times the wire diameter of the wire mesh current collector. The method of claim 1 , further comprising disposing a layer of an anodically active material adjacent to the wire mesh current collector.

7. The method of claim 1, further comprising disposing a cathode active material layer adjacent to the wire mesh current collector.

8. The method of claim 1, further comprising coating the wire mesh current collector with a slurry comprising an anode active material.

9. The method of claim 1, further comprising coating the wire mesh current collector with a slurry comprising a cathode active material.

10. A method of manufacturing a current collector for an electrode of a battery cell, comprising: Providing a wire mesh current collector, which includes wires having a certain diameter and forming grid nodes; rolling the wire mesh current collector using a first roller and a second roller, wherein the first roller and the second roller are spaced apart by a predetermined gap; and supplying electric current to the first roller and the second roller to heat the wire mesh current collector to achieve at least one of: fusing, bonding and welding wires at mesh nodes, The predetermined gap is less than 2 times the wire diameter of the wire mesh current collector.

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