Current collector with three-dimensional structure and battery

Abstract

The utility model discloses a current collector with a three-dimensional structure and a battery, the current collector comprises a current collector body and a three-dimensional structure, the three-dimensional structure is formed on the current collector body, and the three-dimensional structure comprises a plurality of three-dimensional units; each three-dimensional unit comprises a large protruding hole and a plurality of small protruding holes, the small protruding holes are arranged around the periphery of the large protruding hole, and the protruding direction of the small protruding holes is opposite to the protruding direction of the large protruding hole. In this way, the stress of the current collector in the punching machining process can be dispersed, and then the deformation problems of bending or wrinkling and the like of the non-punched blank area of the current collector can be reduced. Meanwhile, the current collector disclosed by the utility model can be used for preparing a thicker battery pole piece, so that not only can the adhesive force between the active layer of the battery pole piece and the current collector be improved, but also the cycle performance, the rate capability and the high and low temperature performance of the battery can be improved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a current collector and battery with a three-dimensional structure. Background Technology

[0002] As a crucial carrier of battery active materials, current collectors effectively gather electrons generated during the electrochemical process and guide them to the electrode plates or outwards to the external circuitry of the battery. Generally, metal current collectors possess excellent conductivity, electrochemical stability, corrosion resistance, and mechanical strength, making them widely used in secondary battery systems. For example, electrolytic copper foil and rolled copper foil can be used as negative electrode current collectors in lithium-ion batteries, while aluminum foil can be used as positive electrode current collectors. Stainless steel strips can be used as negative electrode current collectors in alkaline nickel-metal hydride batteries, while metallic nickel can be used as positive electrode current collectors. Tin-plated copper foil can be used as negative electrode current collectors in alkaline nickel-zinc batteries, while metallic nickel can be used as positive electrode current collectors. To further improve battery energy density and reduce the amount of current collector used, the electrode thickness of alkaline nickel-zinc and nickel-metal hydride batteries is typically quite thick, even reaching 0.2-0.6 mm, primarily achieved by coating the active material using a slurry coating method. Currently, widely used current collectors are typically two-dimensional planar structures, which have poor adhesion to active materials, making it difficult to fabricate thick positive and negative electrode sheets. Furthermore, the electrodes in secondary batteries often expand during charge and discharge, and the active material on the current collector surface is prone to powder shedding, severely impacting the battery's cycle life, rate performance, and high and low temperature performance.

[0003] In the current fields of battery technology and materials science, three-dimensional current collectors have attracted much attention due to their unique structural design and superior electron transport performance. Three-dimensional current collectors not only offer a larger surface area and can accommodate more active material, but also improve the coating effect of active material, effectively enhancing battery charge-discharge performance, cycle stability, rate performance, and high and low temperature performance. Typically, three-dimensional current collectors are created by forming raised through-hole structures on the current collector surface through mechanical punching or laser processing. Laser processing can only create microporous structures on the current collector surface, resulting in poor three-dimensional effects and making it unsuitable for fabricating thicker electrodes. It also suffers from low processing efficiency, high energy consumption, and high manufacturing costs. Therefore, manufacturing three-dimensional current collectors through mechanical punching offers advantages such as high processing efficiency, low energy consumption, and low manufacturing costs, making it more promising for industrialization. However, during the punching process, due to considerations for electrode tab welding, a portion of the current collector's surface must typically be left un-punched for electrode tab welding. Therefore, mechanical stress concentration is inevitably generated during the actual punching process, causing bending or wrinkling deformation problems in the non-punched blank areas of the current collector. This severely affects the structural integrity and performance of the current collector, thus impacting its usability. For example, once the current collector undergoes bending or wrinkling deformation, it becomes difficult to manufacture high-quality battery electrodes during the slip drawing process. It also leads to uneven distribution of active material on both sides of the current collector, especially for batteries with thicker electrode requirements. Most importantly, the wrinkling deformation of the current collector also complicates battery assembly; for instance, the unevenness of the battery electrodes prevents full utilization of the internal space of the battery. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a three-dimensional current collector and battery that can avoid deformation problems such as bending or wrinkling of the blank area of ​​the current collector after punching.

[0005] The objective of this utility model is achieved through the following technical solution:

[0006] A three-dimensional current collector includes: a current collector body and a three-dimensional structure, wherein the three-dimensional structure is formed on the current collector body and the three-dimensional structure includes a plurality of three-dimensional units; each of the three-dimensional units includes a large protruding hole and a plurality of small protruding holes, each of the small protruding holes is arranged around the periphery of the large protruding hole, and the protrusion direction of each of the small protruding holes is opposite to the protrusion direction of the large protruding hole.

[0007] In one embodiment, the three-dimensional units are arranged in an array on the current collector body.

[0008] In one embodiment, the center-to-center distance between the large protrusions in two adjacent three-dimensional units is 1.5 mm to 2.0 mm.

[0009] In one embodiment, the center-to-center distance between the large protrusion and the small protrusion in the same three-dimensional unit is 0.5 mm to 1.0 mm.

[0010] In one embodiment, each of the three-dimensional solid units has four small protrusion holes, which are arranged around the periphery of the large protrusion hole.

[0011] In one embodiment, the longitudinal section of the large protrusion or the small protrusion has a tapered structure.

[0012] In one embodiment, the large protruding hole has a rectangular or circular structure when viewed from above.

[0013] In one embodiment, the small protruding hole has a rectangular or circular structure when viewed from above.

[0014] In one embodiment, the protrusions of the large protrusions in two adjacent three-dimensional units are oriented in opposite directions.

[0015] A battery comprising a current collector with the aforementioned three-dimensional structure.

[0016] Compared with the prior art, the present invention has at least the following advantages:

[0017] 1. This utility model sets multiple three-dimensional units on the body of the current collector. Specifically, by adding several small protrusions around the large protrusion, and making the protrusion direction of the small protrusions opposite to that of the large protrusion, that is, making the punching direction of the small protrusions opposite to that of the large protrusion, the stress during the punching process can be dispersed, thereby reducing the deformation problems such as bending or wrinkling in the non-punched blank area of ​​the current collector. A flat current collector can ensure good performance.

[0018] 2. This utility model improves the current collector's ability to carry slurry during the slurry drawing process by designing the current collector into a three-dimensional structure, and at the same time improves the adhesion between the active layer of the electrode and the current collector, effectively solving the problem of powder shedding of the battery electrode during the preparation process and charging and discharging process.

[0019] 3. By designing the current collector into a three-dimensional structure, this utility model not only helps to prepare thicker battery electrodes and improves the weight energy density of the battery by reducing the amount of current collector, but also effectively improves the battery's cycle performance, rate performance, and high and low temperature performance. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the embodiments will be briefly described below.

[0021] Figure 1 This is a schematic diagram of a three-dimensional current collector according to the first embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of a three-dimensional current collector according to the second embodiment of the present invention;

[0023] Figure 3 for Figure 2 A magnified schematic diagram of the structure at point A;

[0024] Figure 4 This is a schematic diagram of a three-dimensional current collector according to the third embodiment of the present invention;

[0025] Figure 5 This is a cross-sectional view of a three-dimensional current collector structure according to an embodiment of the present invention;

[0026] Figure 6 for Figure 5 A magnified schematic diagram of the structure at point B; Detailed Implementation

[0027] To facilitate understanding of this utility model, a more comprehensive description of this utility model will be given below with reference to the accompanying drawings.

[0028] Please combine Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, a three-dimensional current collector 10 includes: a current collector body 100 and a three-dimensional structure 200. The three-dimensional structure 200 is formed on the current collector body 100 and includes a plurality of three-dimensional units 210. Each three-dimensional unit 210 includes a large protruding hole 211 and a plurality of small protruding holes 212. Each small protruding hole 212 is arranged around the periphery of the large protruding hole 211, and the protrusion direction of each small protruding hole 212 is opposite to the protrusion direction of the large protruding hole 211.

[0029] It should be noted that current collectors typically require a reserved non-punched area for welding the battery electrode tabs. During the punching process of traditional three-dimensional current collectors, stress often causes deformation problems such as bending or wrinkling in the non-punched area. This severely affects the structural integrity and performance of the current collector, consequently impacting its usability. This is especially true for thicker electrodes, where deformation significantly affects the quality of the battery electrode. Therefore, in this invention, by adding a small protrusion 212 (smaller than the large protrusion 211) around the large protrusion 211, and ensuring that the protrusion direction of the small protrusion 212 is opposite to that of the large protrusion 211, the punching direction of the small protrusion 212 is opposite to that of the large protrusion 211, thus dispersing the stress during the punching process. By reducing stress concentration, deformation problems such as bending or wrinkling in the non-perforated blank areas of the current collector can be reduced, thereby improving the actual performance of the current collector.

[0030] It should also be noted that each three-dimensional unit 210 is formed on the current collector body 100 by punching holes. The current collector body 100 is generally made of metal current collector, such as copper, nickel, zinc, aluminum, tin, stainless steel, etc. It may also include metal materials with surface coatings, such as tin-plated copper foil, bismuth-plated copper foil, indium-plated copper foil, silver-plated copper foil, zinc-plated copper foil, tin-plated zinc foil, bismuth-plated zinc foil, indium-plated zinc foil, nickel-plated stainless steel strip, tin-plated stainless steel strip, hot-dip galvanized stainless steel strip, etc. Because metals such as copper, nickel, zinc, aluminum, and tin possess good ductility, during punching, the metal current collector undergoes plastic deformation under the external force of the punch and is stretched to form protruding holes, thus creating a three-dimensional structure 200 for the current collector body 100. This perforated three-dimensional structure design not only improves the current collector's ability to carry slurry during the slurry-pulling process and enhances the adhesion between the electrode active layer and the current collector, solving the problem of electrode powder shedding, but also helps improve the battery's cycle performance, rate performance, and high and low temperature performance. Taking alkaline nickel-zinc batteries as an example, the current collector body 100 is typically made of tin-plated copper foil as the negative electrode current collector. Because the negative electrode slurry composed of the negative electrode active material has a high viscosity and a paste-like consistency with poor fluidity, this is mainly related to the nano-zinc oxide active material and the high solid content of the slurry. Traditional two-dimensional planar current collectors (such as 20μm thick tin-plated copper foil) cannot effectively coat active materials. However, three-dimensional current collectors significantly enhance the current collector's ability to carry slurry during the slurry drawing process, enabling the fabrication of thicker negative electrode sheets (0.2-0.6mm thick) for alkaline nickel-zinc batteries. In alkaline nickel-zinc battery systems, three-dimensional current collectors not only improve the adhesion between active materials such as zinc oxide and the current collector but also enhance the consistency and reliability of the battery's performance. Furthermore, three-dimensional current collectors can help improve the gravimetric energy density, cycle performance, rate performance, and high / low temperature performance of alkaline nickel-zinc batteries.

[0031] Preferably, the three-dimensional units 210 are arranged in an array on the current collector body 100. For example, when the current collector body 100 has a rectangular structure, the three-dimensional units 210 are also arranged in a rectangular array. At the same time, the array distribution structure is more conducive to punching processing.

[0032] Please see Figure 5 and Figure 6As shown, in one embodiment, the longitudinal section of the large protrusion 211 or the small protrusion 212 is conical. The longitudinal section of the large protrusion 211 or the small protrusion 212 refers to the cutting plane perpendicular to the current collector body 100. Since the longitudinal section of the large protrusion 211 or the small protrusion 212 is conical, the corresponding punch die is also conical. This conical design reduces the frictional resistance between the punch die and the current collector body 100, making it easier for the punch die to enter and exit the current collector body 100. This effectively prevents the punch die from damaging or destroying the three-dimensional structure of the current collector body 100. Furthermore, the conical structure of the large protrusion 211 or the small protrusion 212 can further improve the current collector's slurry-carrying capacity, thereby further improving the adhesion between the electrode active layer and the current collector, and further preventing problems such as powder shedding from the battery electrode. It's important to note that damage to the punch die can introduce trace amounts of impurities (such as iron, nickel, and manganese) onto the current collector surface. Therefore, the choice of punch die material is crucial for different types of batteries. Taking alkaline nickel-zinc batteries as an example, if the punch die is made of stainless steel, trace elements like iron, nickel, and manganese can enter the negative electrode through the slurry drawing process. This will severely affect the electrochemical performance of the negative electrode, leading to a decline in the performance of the alkaline nickel-zinc battery. However, if the punch die is made of a copper-zinc alloy, even if trace amounts of copper and zinc enter the negative electrode, these impurities will not have a significant impact on the performance of the alkaline nickel-zinc battery.

[0033] Please see Figure 1 or Figure 2 As shown, preferably, the large protruding hole 211 has a rectangular or circular structure in the top view. For example, when the large protruding hole 211 has a circular structure in the top view, the diameter of the large protruding hole 211 is 0.6mm-1.2mm;

[0034] Please see Figure 1 or Figure 2 As shown, preferably, the small protrusion 212 has a rectangular or circular structure in the top view. For example, when the small protrusion 212 has a circular structure in the top view, the diameter of the small protrusion 212 is 0.05mm-0.2mm.

[0035] In one embodiment, the center-to-center distance between the large protrusions 211 in two adjacent three-dimensional solid units 210 is 1.5mm-2.0mm. This ensures that the center-to-center distance between the large protrusions 211 in two adjacent three-dimensional solid units 210 is kept within a reasonable range, which not only ensures the distribution density of the large protrusions 211, but also reduces problems such as deformation or damage during the punching process.

[0036] In one embodiment, within the same three-dimensional unit 210, the center distance between the large protrusion 211 and the small protrusion 212 is 0.5mm-1.0mm. Similarly, maintaining a reasonable center distance between the large protrusion 211 and the small protrusion 212 can reduce problems such as deformation or damage to the current collector during the punching process.

[0037] Please see Figure 2 As shown, in the second embodiment, each three-dimensional unit 210 has four small protrusion holes 212, which are arranged around the periphery of the large protrusion hole 211. The four small protrusion holes 212 are arranged in a 90-degree circular array around the center point of the large protrusion hole 211, which can further disperse the stress generated during the punching process.

[0038] Please see Figure 4 As shown, in the third embodiment, the four adjacent three-dimensional units 210 are arranged in a rhomboid structure. This facilitates the winding of the current collector during battery core winding, thus preventing uneven stress in the current collector after winding, which could lead to problems such as warping of the wound.

[0039] In one embodiment, the large protruding holes 211 in two adjacent three-dimensional units 210 have opposite protrusion directions. This not only facilitates double-sided coating of the active slurry and improves its adhesion, but also effectively avoids problems such as deformation of the current collector sheet due to unidirectional force during punching, thereby improving punching accuracy and ensuring the punching quality of the current collector. Taking alkaline nickel-zinc batteries as an example, the double-sided coating of active slurry process can effectively improve the processing efficiency of the negative electrode sheet and save costs. In addition, by avoiding deformation problems such as bending or wrinkling in the non-punched blank areas, the punching quality of the current collector is improved, which not only facilitates the tab welding of the negative electrode sheet of alkaline nickel-zinc batteries, but also helps to improve the quality of assembly processes such as battery winding or stacking.

[0040] A battery comprising a current collector of the aforementioned three-dimensional structure 200.

[0041] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A current collector of a three-dimensional structure, characterized by, The collector body comprises: a three-dimensional structure formed on the collector body, the three-dimensional structure comprising a plurality of three-dimensional units; each of the three-dimensional units comprises a large protruding hole and a plurality of small protruding holes, each of the small protruding holes is arranged around the periphery of the large protruding hole, and the protruding direction of each of the small protruding holes is opposite to the protruding direction of the large protruding hole. Each of the three-dimensional units is arranged in an array on the collector body. The longitudinal section of the large protruding hole or the small protruding hole is in a conical structure.

2. The three-dimensional structured current collector of claim 1, wherein The large protruding hole is in a rectangular structure or a circular structure in the top view.

3. The three-dimensional structured current collector of claim 2, wherein The small protruding hole is in a rectangular structure or a circular structure in the top view.

4. The three-dimensional structured current collector of claim 3, wherein The center distance between the large protruding holes of two adjacent three-dimensional units is 1.5-2.0 mm.

5. The three-dimensional structured current collector of claim 3, wherein In the same three-dimensional unit, the center distance between the large protruding hole and the small protruding hole is 0.5-1.0 mm.

6. The three-dimensional structured current collector of any of claims 2-5, wherein, Each of the three-dimensional units is provided with four small protruding holes arranged around the periphery of the large protruding hole.

7. The three-dimensional structured current collector of claim 6, wherein The protruding directions of the large protruding holes of two adjacent three-dimensional units are opposite.

8. The three-dimensional structured current collector of any of claims 2-5, wherein, The collector comprising the three-dimensional structure according to any one of claims 1-9.

9. The three-dimensional structured current collector of any of claims 2-5, wherein, ​ 10. A battery, characterized by ​

Images