A current collector with microgroove structure
By etching microgroove structures and nano-conductive layers on the current collector of lithium-ion batteries, the problems of slow electrolyte wetting and damage during the grooving process were solved, achieving rapid and uniform wetting and improved battery performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HU ZHOU YAO NING GU TAI DIAN CHI YAN JIU YUAN YOU XIAN GONG SI
- Filing Date
- 2025-04-17
- Publication Date
- 2026-06-09
AI Technical Summary
In existing lithium-ion battery manufacturing processes, electrolyte wetting time is long and efficiency is low. Furthermore, the grooving process may damage the electrode structure, laser etching generates dust, leading to loss of active materials, and excessive electrolyte injection causes uneven wetting, affecting battery performance.
A current collector with a microgroove structure is used to form conductive channels on the foil layer by ultraviolet laser etching. Combined with a nano-conductive layer and an electrolyte binding layer, a microgroove structure is constructed to improve the wetting speed and uniformity of the electrolyte, and to ensure the continuity of the active material and the structural strength of the current collector.
It achieves rapid electrolyte wetting, improves battery cycle life and wetting uniformity, and avoids damage to active materials and dust generation caused by laser etching, thus maintaining the battery's volumetric energy density.
Smart Images
Figure CN224342283U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of lithium battery manufacturing technology, and in particular to a current collector with a microgroove structure. Background Technology
[0002] In current lithium-ion battery manufacturing processes, the positive and negative electrodes are typically produced by coating an active material slurry onto the surface of a metal foil (current collector), followed by drying and rolling to form a dense electrode layer. After the electrodes are wound or stacked and assembled into the casing, electrolyte is injected into the battery through a liquid injection process, relying on capillary action to gradually permeate the pores of the active material.
[0003] To improve electrolyte wetting speed, some existing technologies employ physical modification methods, such as creating trenches in the active material layer. However, mechanical trenching can damage the integrity of the electrode structure, increasing the risk of interfacial delamination between the active material layer and the current collector. Simultaneously, the high temperatures generated by laser etching affect the active coating, producing significant dust. This debris may remain in the pores, forming secondary blockage points and ultimately reducing overall wetting efficiency.
[0004] Furthermore, during battery cycling, continuous side reactions occur between the active material and the electrolyte, leading to the continuous consumption of effective electrolyte. Therefore, some existing technologies create a reserve by excessively injecting electrolyte during the filling stage. However, excessive electrolyte can cause insufficient wetting, especially in thick electrode structures where it easily forms a wetting gradient, resulting in intensified local polarization. While the grooving process in the active material layer can establish electrolyte diffusion channels, it directly leads to a loss of active material coating area, significantly sacrificing the battery's volumetric energy density. The grooving process requires high coordination with existing coating, rolling, and winding processes, making the process complex and costly. Utility Model Content
[0005] To address the problems of long electrolyte injection time, long immersion time, and poor immersion effect in existing technologies, this invention provides a current collector with a microgroove structure, comprising a foil layer and an electrolyte binding layer; main grooves are formed on both sides of the foil layer along its longitudinal direction (electrolyte immersion direction); the electrolyte binding layer is a nano-conductive layer, which covers the surface of the foil layer and fills the interior of the main grooves.
[0006] Furthermore, the depth D of the main channel flow is less than 1 / 2 of the thickness H of the foil layer; the main channels flows on both sides of the foil layer are interlaced and evenly distributed along the transverse direction of the foil layer.
[0007] Furthermore, any one of the main channels on one side of the foil layer corresponds to the middle position of the two closest main channels on the other side.
[0008] Furthermore, the distance S between two adjacent main channels is 0.5 to 10 cm.
[0009] Furthermore, multiple secondary channels extend from the single main channel, and the electrolyte binding layer fills the interior of the secondary channels; the secondary channels are obliquely oriented towards the lower part of the main channel; the channel depth d of the secondary channels is less than 1 / 2 of the foil layer thickness H.
[0010] Furthermore, the secondary channel flows are evenly distributed on a single main channel flow, and the distance t between two adjacent secondary channel flows on a single main channel flow is 0.5 to 10 mm.
[0011] Furthermore, the width of the opening end of the main channel is greater than the width of its closed end at the bottom. The width of the opening end of the main channel is 20-50 μm, and the width of the closed end at the bottom is 10-20 μm.
[0012] Furthermore, the width of the opening end of the secondary channel is greater than the width of its closed end at the bottom. The width of the opening end of the secondary channel is 0–5 μm, and the width of the closed end at the bottom is 0–10 μm.
[0013] Furthermore, the electrolyte binding layer includes conductive carbon black, graphene, conductive carbon nanotubes, binder, and dispersant.
[0014] Compared with the prior art, this utility model has the following beneficial effects:
[0015] While ensuring the structural strength of the current collector structure itself, ultraviolet laser is used to directly directionally etch the current collector to form electrolyte flow channels. Firstly, the high temperature generated by laser etching will not affect the active materials in the battery electrodes, and no significant dust will be produced, ensuring the continuity of the active materials and their adhesion strength to the current collector. Secondly, during the electrolyte wetting stage, conductive particles in the electrolyte binding layer form porous channels between the micro-grooves and on the surface of the foil layer, allowing the electrolyte to effectively flow and penetrate directionally through capillary effect. The electrolyte can be quickly absorbed and wetted into the foil layer and retained in the micro-grooves. When the electrolyte is consumed during battery use, the electrolyte flowing into the micro-grooves can replenish it, improving battery cycle life. Attached Figure Description
[0016] Figure 1 This is a view of the main channel flow along its thickness direction in the structure of this application;
[0017] Figure 2 This is a schematic diagram of the bilaterally symmetrical and equidistant distribution of the secondary channel flow in this application;
[0018] Figure 3 This is a schematic diagram of the double-sided staggered equidistant distribution of the secondary channel flow in this application;
[0019] Figure 4 This is a schematic diagram of the unilateral equidistant distribution of the secondary channel flow in this application;
[0020] In the diagram: 1. Foil layer; 2. Electrolyte binding layer; 3. Main tank flow; 4. Secondary tank flow. Detailed Implementation
[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.
[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The terms "upper," "lower," "front," "rear," "top," "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or part referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. It should be understood that such data can be interchanged where appropriate for the embodiments of this utility model described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.
[0023] like Figures 1-4 As shown, a current collector with a microgroove structure includes a foil layer 1 and an electrolyte binding layer 2; both sides of the foil layer 1 are along its longitudinal direction (electrolyte wetting direction, i.e. Figures 1-4 A main flow channel 3 is provided in the y-direction of the foil layer 1. The electrolyte binding layer 2 is a nano-conductive layer that covers the surface of the foil layer 1 and fills the interior of the main flow channel 3.
[0024] Current collectors are usually made of metal foil. When foil layer 1 is used for the positive electrode, aluminum foil is commonly used; when foil layer 1 is used for the negative electrode, copper foil is commonly used.
[0025] By directly etching the current collector with an ultraviolet laser to form electrolyte flow channels, two advantages are achieved. First, compared to existing methods of etching grooves on the active material, the high temperature generated by laser etching does not affect the active material in the battery electrode, and no significant dust is produced. This also ensures the continuity of the active material and its adhesion strength to the current collector. Second, during the electrolyte wetting stage, conductive particles in the electrolyte binding layer 2 form porous channels between the main channel flow 3 and on the surface of the foil layer 1. This allows the electrolyte to flow and penetrate effectively through capillary action, enabling rapid absorption and wetting of the electrolyte into the foil layer 1, where it remains in the main channel flow 3. When the electrolyte is consumed during battery use, it can be replenished by electrolyte permeating into the microchannel flow, improving battery cycle life.
[0026] While etching the surface of foil layer 1 to form the main channel flow 3, it is also necessary to ensure the structural strength of the current collector structure itself. The channel depth D of the main channel flow 3 is less than 1 / 2 of the thickness H of foil layer 1. The main channel flows 3 on both sides of foil layer 1 are staggered and evenly distributed along the transverse (z direction) of foil layer 1.
[0027] In a preferred embodiment, such as Figure 1 As shown, any one main channel flow 3 on one side of the foil layer 1 corresponds to the middle position of the two closest main channel flows 3 on the other side. This ensures that the main channel flows 3 on both sides of the foil layer 1 are completely uniformly and equidistantly distributed, further guaranteeing the structural strength and stability of the current collector itself.
[0028] The distance S between two adjacent main flow channels 3 is 0.5 to 10 cm. The specific value can be determined according to the strength and wetting capacity requirements of the product foil.
[0029] To further improve the wetting rate and optimize the microgroove structure on the foil layer 1, multiple secondary groove flows 4 branch out from a single main groove flow 3, with the electrolyte binding layer 2 filling the interior of the secondary groove flows 4. The secondary groove flows 4 are angled towards the lower part of the main groove flow 3; as shown... Figure 2 As shown, the angle between the secondary channel flow 4 and the main channel flow 3 is 60°. The channel depth d of the secondary channel flow 4 is less than 1 / 2 of the thickness H of the foil layer 1.
[0030] Preferably, the secondary channel flows 4 are evenly distributed on a single main channel flow 3, and the distance t between two adjacent secondary channel flows 4 on a single main channel flow 3 is 0.5–10 mm. It should be noted that, as... Figures 2-4 As shown, the secondary channel flow 4 can be symmetrically and equidistantly distributed on both sides of the main channel flow 3, or staggered and equidistantly distributed on both sides of the main channel flow 3, or equidistantly distributed on one side of the main channel flow 3.
[0031] It should be noted that the cross-sections of the main flow channel 3 and the secondary flow channel 4 are not limited to those shown below. Figure 1The trapezoidal shape shown can also be U-shaped, semi-circular, rectangular, or square. A larger opening at the trench opening facilitates rapid entry of the electrolyte into the trench. Preferably, as... Figure 1 The trapezoidal cross-section shown can balance the structural strength of foil layer 1 and the electrolyte wetting performance.
[0032] The opening width of the main flow channel 3 is greater than the closing width of its bottom end. The opening width of the main flow channel 3 is 20–50 μm, and the closing width of its bottom end is 10–20 μm. The opening width of the secondary flow channel 4 is greater than the closing width of its bottom end. The opening width of the secondary flow channel 4 is 0–5 μm, and the closing width of its bottom end is 0–10 μm.
[0033] like Figure 1 As shown, the electrolyte binding layer 2 includes conductive carbon black, graphene, conductive carbon nanotubes, binder, and dispersant. A higher proportion of conductive carbon black results in a more pronounced capillary effect. A higher proportion of graphene leads to better electrolyte storage performance and faster electrolyte wetting speed.
[0034] Preferably, by weight percentage of materials, conductive carbon black accounts for 50-70%, graphene accounts for 20-30%, conductive carbon nanotubes account for 5-10%, binder accounts for 5-10%, and dispersant accounts for 0.5-5%.
[0035] Based on the particle size distribution of the material, conductive carbon black has a D50 ≤ 1 μm and a specific surface area ≥ 75 m². 2 / g; Graphene D50≤20μm, specific surface area≥150m² 2 / g, number of layers ≤10; conductive carbon nanotubes D50≤12μm, specific surface area ≥200m² 2 / g.
[0036] The following is a brief description of the fabrication process of a current collector with a microgroove structure.
[0037] A finished foil layer 1 (aluminum foil) with a thickness H of 12μm is placed in a laser etching machine for etching. The depth D of the main groove flow 3 is 4μm, the bottom width of the groove is 15μm, and the opening width of the groove is 35μm. The main groove flows 3 are uniformly distributed along the length direction (x direction) of the foil layer 1, and the spacing S between two adjacent main groove flows 3 is 2mm.
[0038] Secondary grooves 4 are etched symmetrically and uniformly on both sides of the main groove 3, with an angle of 60° between the secondary grooves 4 and the main groove 3. The etching depth d of the secondary grooves 4 is 3μm, the bottom width is 5μm, the opening width is 10μm, and the spacing between two adjacent grooves is 1mm.
[0039] After etching the first side, the second side is etched by reverse rolling. The positions of the main channel flow 3 and the secondary channel flow 4 on the second side are offset by 1mm relative to the positions of the channel flows on the first side that have been etched. The etching structure is the same as that of the first side.
[0040] An electrolyte binding layer is covered in the main flow 3 and the secondary flow 4 and on the surface of the foil layer 1. This layer is a nano-conductive layer, in which carbon black accounts for 65%, graphene accounts for 24%, conductive carbon nanotubes account for 5%, binder accounts for 5%, and dispersant accounts for 1%.
[0041] The composition and physical properties are as follows: conductive carbon black D50: 0.5μm, specific surface area: 90m². 2 / g; Graphene D50: 10μm, specific surface area: 165m² 2 / g, number of layers ≤10; conductive carbon nanotube D50: 9μm, specific surface area: 270m² 2 / g. The electrolyte binding layer thickness is 5μm.
[0042] By opening symmetrically and equidistantly distributed secondary channels 4 on both sides of the main channel 3, and comparing them with a current collector without microchannel structure, the results are shown in Table 1.
[0043] Table 1
[0044]
[0045] The test results show that by opening the main channel flow 3 and the secondary channel flow 4 on the foil layer 1, this current collector structure can improve the uniformity of electrolyte distribution, shorten the electrolyte immersion time by more than 50%, and increase the battery cycle life by 5% to 20%.
[0046] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of implementation of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this utility model, and all such improvements and modifications should be covered within the protection scope of this utility model.
Claims
1. A current collector with a microgroove structure, characterized in that, It includes a foil layer (1) and an electrolyte binding layer (2); the foil layer (1) has a main channel flow (3) on both sides along its longitudinal direction; the electrolyte binding layer (2) is a nano-conductive layer, and the electrolyte binding layer (2) covers the surface of the foil layer (1) and fills the interior of the main channel flow (3).
2. A current collector with a microgroove structure according to claim 1, characterized in that, The groove depth D of the main groove flow (3) is less than 1 / 2 of the thickness H of the foil layer (1); the main groove flows (3) on both sides of the foil layer (1) are interlaced and evenly distributed along the transverse direction of the foil layer (1).
3. A current collector with a microgroove structure according to claim 2, characterized in that, One of the main channels (3) on one side of the foil layer (1) corresponds to the middle position of the two main channels (3) that are closest to it on the other side.
4. A current collector with a microgroove structure according to claim 1, characterized in that, The distance S between two adjacent main channel flows (3) is 0.5~10cm.
5. A current collector with a microgroove structure according to claim 1, characterized in that, Multiple secondary channels (4) branch out from a single main channel (3), and the electrolyte binding layer (2) fills the interior of the secondary channels (4); the secondary channels (4) are obliquely oriented towards the lower part of the main channel (3); the channel depth d of the secondary channels (4) is less than 1 / 2 of the thickness H of the foil layer (1).
6. A current collector with a microgroove structure according to claim 5, characterized in that, The secondary channel flows (4) are evenly distributed on a single main channel flow (3), and the distance t between two adjacent secondary channel flows (4) on a single main channel flow (3) is 0.5~10mm.
7. A current collector with a microgroove structure according to claim 1, characterized in that, The width of the opening end of the main channel (3) is greater than the width of the closed end of the channel bottom. The width of the opening end of the main channel (3) is 20~50μm, and the width of the closed end of the channel bottom is 10~20μm.
8. A current collector with a microgroove structure according to claim 5, characterized in that, The width of the opening end of the secondary channel (4) is greater than the width of the closed end of the channel bottom. The width of the opening end of the secondary channel (4) is 0~5μm, and the width of the closed end of the channel bottom is 0~10μm.
9. A current collector with a microgroove structure according to claim 1, characterized in that, The electrolyte binding layer (2) includes conductive carbon black, graphene, conductive carbon nanotubes, binder and dispersant.