Composite pole piece
By setting multiple layers of coating on the lithium-ion battery electrode and forming pores and grooves on the surface, the problem of poor electrolyte wetting is solved, the charge and discharge rate and cycle performance of the battery are improved, and the battery life is extended.
Patent Information
- Application Number
- CN202422922035.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-28
- Publication Date
- 2026-01-06
- Estimated Expiration
- 2034-11-28
AI Technical Summary
In the process of improving energy density and material compaction density, existing lithium-ion batteries suffer from poor electrolyte wetting, resulting in deterioration in rate performance and long-cycle performance.
A composite electrode structure is adopted, and multiple layers are coated on the current collector. The third layer has concave holes and/or grooves on its surface, which are formed by laser drilling and/or laser scribing processes to ensure electrolyte wetting and lithium ion diffusion channels.
Under high-pressure conditions, it promotes electrolyte wetting, improves charge/discharge rate and cycle stability, reduces capacity loss, and extends battery life.
Smart Images
Figure CN223771103U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the technical field of secondary batteries, and specifically relates to a composite electrode. Background Technology
[0002] In today's era of rapid technological advancement, rechargeable battery technology is iterating and updating at an unprecedented pace, with performance standards for battery products constantly improving, showcasing many remarkable features such as fast charging technology. These advanced technological innovations are profoundly changing our lifestyles, bringing unprecedented convenience and efficiency to all aspects of our lives, including clothing, food, housing, and travel.
[0003] With the continuous upgrading and development of terminal product technology, the requirements for energy density, charge / discharge speed, and safety performance of lithium-ion batteries are increasing. Developing fast-charging lithium-ion batteries with high energy density, high safety performance, and long lifespan is of great significance. The key factors for improving the energy density of lithium-ion batteries mainly focus on three aspects: materials, processes, and design. Among these, improvements and upgrades in materials and processes have the most significant impact on energy density. While high-specific-capacity materials can improve battery energy density, they may also have some drawbacks. For example, silicon-carbon and silicon-oxygen anode materials, while possessing high specific capacity, also suffer from low compaction density, high cycle expansion rate, easy pulverization in the later stages of cycling, and rapid energy loss in the later stages of cycling. In terms of processes, improving the compaction density of materials is one of the most direct and convenient methods to improve the overall energy density of the battery. However, while increasing the compaction density, the porosity between active materials decreases, the capillary effect weakens after electrolyte injection, the wetting time becomes longer, and the wetting effect deteriorates, potentially leading to a decline in the battery's rate performance and long-cycle performance.
[0004] Therefore, given this situation, there is an urgent need to develop a new type of composite electrode to solve the aforementioned problems. Utility Model Content
[0005] One of the objectives of this invention is to provide a composite electrode that, in response to the shortcomings of existing technologies, has high capacity, high solid density, good electrolyte wetting channels and electrolyte retention capacity, and long cycle life.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A composite electrode, comprising:
[0008] current collector;
[0009] A first coating is disposed on at least one surface of the current collector;
[0010] The second coating is applied to the surface of the first coating;
[0011] A third coating is applied to the surface of the second coating, and the surface of the third coating is provided with a plurality of holes and / or a plurality of grooves.
[0012] Preferably, the diameter of the concave hole is 100μm to 200μm.
[0013] Preferably, the distance between two adjacent recesses is 0.5mm to 2mm.
[0014] Preferably, the groove width is 100μm to 200μm.
[0015] Preferably, the distance between two adjacent grooves is 0.5mm to 3mm.
[0016] Preferably, the depth of the concave hole or the groove is 40 to 190 μm.
[0017] Preferably, the plurality of recesses and / or grooves on the surface of the third coating are formed by laser drilling and / or laser scribing processes.
[0018] Preferably, the thickness ratio of the first coating, the second coating, and the third coating is 3-10:200-600:500-2000.
[0019] Preferably, the thickness of the first coating is 0.3 to 1 μm, the thickness of the second coating is 20 to 60 μm, and the thickness of the third coating is 50 to 200 μm.
[0020] Preferably, the compaction density of the second coating is 1.6–1.75 g / cm³. 3 The compaction density of the third coating is 1.65–1.8 g / cm³. 3 .
[0021] Preferably, the second coating includes a first active material with a specific capacity of 420 mAh / g to 600 mAh / g, and the third coating includes a second active material with a specific capacity of 340 mAh / g to 380 mAh / g.
[0022] Compared to existing technologies, the advantages of this invention are as follows: the composite electrode of this invention includes: a current collector; a first coating disposed on at least one surface of the current collector; a second coating coated on the surface of the first coating; and a third coating coated on the surface of the second coating, wherein the surface of the third coating is provided with a plurality of recesses or grooves. Through the plurality of recesses and / or grooves on the surface of the third coating, it is possible to ensure that the third coating, under high compaction conditions, can simultaneously promote the wetting and flow of the electrolyte, ensuring the electrolyte retention effect of the electrode and the rapid formation of fast channels for lithium-ion diffusion; it can also ensure that the capacity loss caused by the recesses or grooves remains at a low level. Attached Figure Description
[0023] The features, advantages and technical effects of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings.
[0024] Figure 1 This is a schematic diagram of the structure of a composite electrode sheet according to an embodiment of the present invention;
[0025] Figure 2 This is a top view of a composite electrode sheet according to an embodiment of the present invention;
[0026] Figure 3 This is a top view of a composite electrode sheet according to another embodiment of the present invention.
[0027] The reference numerals in the attached figures are explained as follows:
[0028] 1. Current collector; 2. First coating; 3. Second coating; 4. Third coating; 41. Hole; 42. Groove. Detailed Implementation
[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0030] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.
[0031] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0032] In the embodiments of this application, the same reference numerals denote the same parts, and for the sake of brevity, detailed descriptions of the same parts are omitted in different embodiments.
[0033] In this application, "several" refers to two or more (including two).
[0034] The following is in conjunction with the appendix Figures 1-3 The present invention will be further described in detail with reference to specific embodiments, but this is not intended to limit the present invention.
[0035] like Figures 1-3 As shown, a composite electrode includes:
[0036] current collector 1;
[0037] A first coating 2 is disposed on at least one surface of the current collector 1;
[0038] The second coating 3 is applied to the surface of the first coating 2;
[0039] The third coating 4 is applied to the surface of the second coating 3, and the surface of the third coating 4 is provided with a plurality of recesses 41 and / or a plurality of grooves 42.
[0040] The first coating 2 is applied to the current collector 1 by gravure coating and / or extrusion coating. The second coating 3 and the third coating 4 are applied to the first coating layer by transfer coating and / or extrusion coating / double coating. The function of the first coating 2 is to enhance the adhesion between the current collector 1 and the second coating 3, and at the same time increase the electronic conductivity between the second coating 3 and the first coating 2.
[0041] The first coating 2 consists of a binder and a conductive agent; the second coating 3 consists of a high specific capacity, small particle size active material; and the third coating 4 consists of a high compaction density, large particle size active material. All materials selected are conventional materials in the art.
[0042] The third coating 4 forms several recesses 41 and / or several grooves 42 on its surface by laser drilling and / or laser scribing before or after the electrode is rolled.
[0043] The several recesses 41 and / or several grooves 42 on the surface of the third coating 4 can ensure that the third coating 4 is in high-pressure compaction condition, while also ensuring the wetting and flow of electrolyte, promoting the electrolyte retention effect of the electrode and the rapid formation of fast channels for lithium-ion diffusion; it can also ensure that the capacity loss caused by the recesses 41 or grooves 42 is kept at a low level.
[0044] In one embodiment of the present invention, the diameter of the recessed hole 41 is 100μm to 200μm, for example, it can be 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, or 200μm. A recessed hole 41 with a diameter of 100μm to 200μm ensures sufficient contact area between the electrode and the electrolyte; it can also form ion channels, shortening the migration distance of ions in the electrode, which helps to improve the charge and discharge rate of the battery, enabling the battery to respond more quickly to changes in external load; it can also alleviate this volume effect, preventing damage to the electrode structure, thereby improving the cycle stability of the battery. If the diameter or depth of the recessed hole 41 is too large, it will lead to an increase in the weight loss rate of the negative electrode active material, a decrease in the NP ratio of the positive and negative electrode active materials, resulting in reduced battery capacity, reduced capacity retention in the later stages of cycling, and an increased risk of lithium plating. 。
[0045] In one embodiment of the present invention, the spacing between two adjacent recesses 41 is 0.5 mm to 2 mm, for example, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, or 2 mm. An appropriate hole spacing ensures that the electrolyte fully wets the electrode surface, resulting in a more complete electrochemical reaction; it also helps optimize the ion transport path, shortens the migration distance of ions in the electrode, and improves the charge and discharge rate of the battery. An excessively large hole spacing reduces the contact area between the electrolyte and the electrode, leading to an incomplete electrochemical reaction.
[0046] In one embodiment of the present invention, the width of the groove 42 is 100μm to 200μm, for example, it can be 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, or 200μm. A groove width of 100μm to 200μm ensures sufficient contact area between the electrode and the electrolyte; it can also form ion channels, shortening the migration distance of ions in the electrode, which helps to improve the charge and discharge rate of the battery, enabling the battery to respond more quickly to changes in external load; it can also alleviate this volume effect, prevent damage to the electrode structure, and thus improve the cycle stability of the battery. If the width of the groove 42 is too large or too deep, it will lead to increased weight loss of the negative electrode active material, a decrease in the NP ratio of the positive and negative electrode active materials, and a reduction in battery capacity. In principle, if the width of the groove 42 is too large or too deep, it will cause the negative electrode active material to accept Li... + The space for ion intercalation is reduced, allowing Li to accept... + The ability of ions decreases, and the capacity is prone to drop and lithium plating in the later stages of cycling.
[0047] In one embodiment of the present invention, the spacing between two adjacent grooves 42 is 0.5mm to 3mm, for example, it can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, or 3mm. An appropriate spacing ensures that the electrolyte fully wets the electrode surface, resulting in a more complete electrochemical reaction, thereby improving the battery's capacity and energy density; it also helps optimize the ion transport path, shortening the migration distance of ions in the electrode and improving the battery's charge and discharge rate.
[0048] In one embodiment of the present invention, the depth of the recessed hole 41 or the groove 42 is 40–190 μm, for example, it can be 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, or 190 μm. Appropriate depth of the recessed hole 41 or the groove 42 can increase the effective reaction area of the electrode and improve the charge and discharge efficiency of the battery. If the markings are too shallow, the reaction area may be insufficient, reducing the charge and discharge efficiency and failing to improve the wettability to the electrolyte.
[0049] In one embodiment of the present invention, the plurality of recessed holes 41 and / or the plurality of grooves 42 provided on the surface of the third coating 4 are formed by laser drilling and / or laser scribing processes.
[0050] In one embodiment of the present invention, the thickness ratio of the first coating 2, the second coating 3 and the third coating 4 is 3-10:200-600:500-2000.
[0051] In one embodiment of the present invention, the thickness of the first coating 2 is 0.3–1 μm, for example, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, or 1 μm; the thickness of the second coating 3 is 20–60 μm, for example, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, or 60 μm; and the thickness of the third coating 4 is 50–200 μm, for example, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, or 200 μm.
[0052] In one embodiment of the present invention, the compaction density of the second coating 3 is 1.6–1.75 g / cm³. 3 For example, it can be 1.6 g / cm³. 3 1.61 g / cm 3 16.2g / cm 3 16.3g / cm 3 16.4g / cm 3 16.5g / cm 3 16.7g / cm 3 16.8g / cm 3 1.69 g / cm 3 1.70g / cm 3 1.71g / cm3 1.72g / cm 3 1.73g / cm 3 1.74 g / cm 3 1.75g / cm 3 The second coating 3 includes a first active material with a specific capacity of 420–600 mAh / g, for example, 420 mAh / g, 430 mAh / g, 440 mAh / g, 450 mAh / g, 460 mAh / g, 470 mAh / g, 480 mAh / g, 490 mAh / g, 500 mAh / g, 510 mAh / g, 520 mAh / g, 530 mAh / g, 540 mAh / g, 550 mAh / g, 560 mAh / g, 570 mAh / g, 580 mAh / g, 590 mAh / g, or 600 mAh / g. The first active material includes one of silicon-carbon, silicon-oxygen, artificial graphite, natural graphite, hard carbon, soft carbon, or carbon microspheres. More preferably, the first active material contains silicon-carbon, silicon-oxygen, or other high-specific-capacity, high-rate-capacity, and high-first-efficiency active materials. The function of the second coating 3 is to improve the battery's first-time efficiency, increase specific capacity, and thus improve the overall energy density of the battery.
[0053] In one embodiment of the present invention, the compaction density of the third coating 4 is 1.65–1.8 g / cm³. 3 For example, it can be 16.7 g / cm³. 3 16.8g / cm 3 1.69 g / cm 3 1.70g / cm 3 1.71g / cm 3 1.72g / cm 3 1.73g / cm 3 1.74 g / cm 3 1.75g / cm 3 1.76 g / cm 3 1.77g / cm 3 1.78g / cm 3 1.79g / cm 3 1.80g / cm 3The third coating 4 includes a second active material with a specific capacity of 340–380 mAh / g, for example, 340 mAh / g, 345 mAh / g, 350 mAh / g, 355 mAh / g, 360 mAh / g, 365 mAh / g, 370 mAh / g, 375 mAh / g, or 380 mAh / g. The second active material includes one of artificial graphite, natural graphite, hard carbon, soft carbon, or carbon microspheres. More preferably, the second active material is high-compact graphite. The main function of the third coating 4 is to improve the overall compaction of the composite negative electrode, reduce the thickness of the composite electrode sheet, and create pores or scribing on its surface. This ensures that the electrode sheet can withstand high compaction while also promoting effective electrolyte wetting and effective ion diffusion and transport channels. 。
[0054] Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments described above, and any obvious improvements, substitutions, or modifications made by those skilled in the art based on this utility model are within the protection scope of this utility model. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this utility model.
Claims
1. A composite pole piece characterized by, The application relates to a current collector, which comprises: a current collector; a first coating layer arranged on at least one surface of the current collector; a second coating layer arranged on the surface of the first coating layer; and a third coating layer arranged on the surface of the second coating layer, wherein the surface of the third coating layer is provided with a plurality of concave holes and / or a plurality of grooves. The diameter of the concave holes is 100-200 mu m. The interval between two adjacent concave holes is 0.5-2 mm. The width of the grooves is 100-200 mu m. The interval between two adjacent grooves is 0.5-3 mm.
2. The composite pole piece of claim 1, wherein, The depth of the concave holes or the grooves is 40-190 mu m.
3. The composite pole piece of claim 1, wherein, The plurality of concave holes and / or the plurality of grooves arranged on the surface of the third coating layer are formed by a laser drilling and / or laser scribing process.
4. The composite pole piece of claim 1, wherein, The thickness ratio of the first coating layer, the second coating layer and the third coating layer is 3-10:200-600:500-2000.
5. The composite pole piece of claim 1, wherein, The thickness of the first coating layer is 0.3-1 mu m, the thickness of the second coating layer is 20-60 mu m, and the thickness of the third coating layer is 50-200 mu m.
6. The composite pole piece of claim 1, wherein, 7. The composite pole piece of claim 1, wherein, 8. The composite pole piece of claim 1, wherein, 9. The composite pole piece of claim 1, wherein, 10. The composite pole piece of claim 1, wherein, The second coating has a compacted density of 1.6 to 1.75 g / cm 3 The third coating has a compacted density of 1.65 to 1.8 g / cm 3 .