Pole piece and battery
By defining the particle size in the first active material layer of the electrode sheet, the problem of insufficient adhesion between the active material layer and the current collector is solved, and the long-term cycle performance of the battery is improved and the cost reduction is reduced.
Patent Information
- Application Number
- CN202421291410.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-06
- Publication Date
- 2025-06-13
- Estimated Expiration
- 2034-06-06
AI Technical Summary
The bonding strength of the active material layer in existing batteries to the current collector is poor, affecting the long-term circulation performance of the battery, and adding a primer to improve the bonding effect will increase costs and reduce energy density.
By defining the particle size from 3.5 microns to 4.5 microns in the first active material layer of the electrode sheet, it is possible to embed into the current collector during rolling pressure, and the adhesion between the active material layer and the current collector is significantly enhanced, and the use of a primer layer is avoided.
The stability of the pole plate structure and the long-term circulation performance of the battery are significantly improved, while reducing costs and improving energy density.
Smart Images
Figure CN222980514U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of new energy, and particularly provides a pole piece and a battery. Background Art
[0002] With the development of society and the enhancement of environmental awareness, new energy is gradually replacing traditional energy and has been developing rapidly, including batteries.
[0003] Existing batteries generally include a housing and an electric core housed in the housing. The electric core includes multiple pole pieces and a separator located between the pole pieces, and the pole piece includes a current collector and an active material layer provided on the current collector. However, the particle size of the particles in the existing active material layer is usually small, for example, between 1 micron and 2.5 microns, resulting in a low compaction density of the active material layer, poor contact with the current collector after rolling, poor adhesion between the active material layer and the current collector, and affecting the long-term cycle performance of the battery. Therefore, in order to improve the above problems, a bottom coating is usually added between the current collector and the active material layer, but the bottom coating will increase the cost and reduce the energy density of the electric core.
[0004] Therefore, a new technical solution is needed in this field to solve the above problems. Summary of the Utility Model
[0005] The utility model aims to solve the above technical problems, that is, to solve the problem that the adhesion effect between the existing current collector and the active material layer is not ideal.
[0006] In a first aspect, the utility model provides a pole piece, which includes a current collector and a first active material layer. The current collector includes a first surface, and the first active material layer is provided on the first surface. The particle size of the particles in the first active material layer is g 1 , where 3.5 microns ≤ g 1 ≤ 4.5 microns.
[0007] In the case of adopting the above technical solution, by defining the particle size of the particles in the first active material layer as above, when the first active material layer is rolled onto the first surface of the current collector, the particles of the first active material layer can effectively embed into the current collector, thereby significantly increasing the adhesion between the first active material layer and the current collector, ensuring the stability of the pole piece structure and the long-term cycle performance of the battery. At the same time, there is no need to set a bottom coating between the first active material layer and the current collector, thereby significantly reducing the cost and increasing the energy density.
[0008] In a preferred technical solution of the above pole piece, the roughness of the first surface is R 1 , where 0.01 microns ≤ R 1 ≤ 4 microns.
[0009] In the preferred technical solution of the above-mentioned electrode, 0.1 μm ≤ R 1 ≤ 3.5 μm.
[0010] In the preferred technical solution of the above-mentioned electrode, the electrode further includes a second active material layer disposed on the surface of the first active material layer, the first active material layer is disposed between the current collector and the second active material layer, and the particle size of the particles in the second active material layer is g 2 , where 1 μm ≤ g 2 ≤ 2.5 μm.
[0011] In the preferred technical solution of the above-mentioned electrode, the peel strength between the first active material layer and the current collector is σ, where 4 N / m ≤ σ ≤ 80 N / m.
[0012] In the preferred technical solution of the above-mentioned electrode, the depth of embedding of the first active material layer into the current collector is h, where 0.1 μm ≤ h ≤ 5 μm.
[0013] In the preferred technical solution of the above-mentioned electrode, the porosity of the first active material layer is p 1 , where 25% ≤ p 1 ≤ 35%.
[0014] In the preferred technical solution of the above-mentioned electrode, the porosity of the second active material layer is p 2 , where 20% ≤ p 2 ≤ 30%.
[0015] In the preferred technical solution of the above-mentioned electrode, the thickness of the first active material layer is t 1 , where 1 μm ≤ t 1 ≤ 100 μm; and / or, the thickness of the second active material layer is t 2 , where 1 μm ≤ t 2 ≤ 100 μm.
[0016] In a second aspect, the present invention further provides a battery, and the battery includes the above-mentioned electrode. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. In the drawings:
[0018] Figure 1 is a perspective view of the current collector of the present invention;
[0019] Figure 2 is a cross-sectional view of the electrode of the present invention.
[0020] List of reference numerals:
[0021] 1. Current collector; 11. First surface; 12. Second surface; 2. First active material layer; 3. Second active material layer. Specific embodiments
[0022] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present invention and are not intended to limit the protection scope of the present invention.
[0023] It should be noted that in the description of the present invention, the terms "inner", "outer", "upper", "lower", "top", "bottom", "left", "right", "front", "rear", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the drawings. This is only for convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.
[0024] In addition, it should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "arranged", "connected", and "installed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0025] Specifically, first refer to Figure 1 and Figure 2 , Figure 1 is a perspective view of the current collector of the present invention, Figure 2 is a cross-sectional view of the electrode plate of the present invention.
[0026] In one embodiment, as shown in Figure 1 and Figure 2 shown, the electrode plate of the present invention includes a current collector 1 and a first active material layer 2. The current collector 1 includes a first surface 11, and the first active material layer 2 is arranged on the first surface 11.
[0027] Preferably, the current collector 1 can be selected as copper foil, aluminum foil, etc. according to needs. For example, when the electrode plate is a positive electrode plate, the current collector 1 can be aluminum foil; when the electrode plate is a negative electrode plate, the current collector 1 can be copper foil, etc. The material of the current collector 1 can be selected and set according to needs and will not be specifically limited here.
[0028] More preferably, the shape of the current collector 1 can be selected and set according to needs. For example, it can be a cuboid or a polyhedron, etc. In this embodiment, the current collector 1 is a cuboid.
[0029] More preferably, the first surface 11 is one end surface of the current collector 1 in the thickness direction and also the surface with the largest area of the current collector 1.
[0030] Furthermore, the material of the first active material layer 2 can be selected and set as needed. For example, when the electrode is a positive electrode, the first active material layer 2 is preferably a positive electrode active material such as lithium iron phosphate; when the electrode is a negative electrode, the first active material layer 2 is preferably a negative electrode active material such as graphite or silicon, so as to meet different usage requirements and expand the scope of use.
[0031] Even further, the first active material layer 2 is preferably disposed on the first surface 11 of the current collector 1 by a coating process, so as to achieve a firm connection between the first active material layer 2 and the current collector 1.
[0032] Even further, the current collector 1 further includes a second surface 12 opposite to the first surface 11, and two first active material layers 2 can be provided and respectively coated on the first surface 11 and the second surface 12, so as to make full use of the current collector 1.
[0033] In one embodiment, the particle size of the particles in the first active material layer 2 is g 1 , where 3.5 microns ≤ g 1 ≤ 4.5 microns.
[0034] Preferably, the particle size g of the particles in the first active material layer 2 1 can be any value between 3.5 microns and 4.5 microns, such as 3.5 microns, 3.6 microns, 3.7 microns, 3.8 microns, 3.9 microns, 4.0 microns, 4.1 microns, 4.2 microns, 4.3 microns, 4.4 microns, 4.5 microns, etc. The user can select and set according to needs and no specific limitation is made here.
[0035] The particle size g of the particles in the first active material layer 2 1 can be selected to be between 3.5 microns and 4.5 microns, so that when it is coated on the current collector 1, it can adhere better to the current collector 1, significantly increase the adhesion between the first active material layer 2 and the current collector 1, improve the stability of the structure, prevent the first active material layer 2 from detaching from the current collector 1, and at the same time, there is no need to provide a primer layer between the current collector 1 and the first active material layer 2, which can significantly reduce costs and omit process steps.
[0036] In one embodiment, the roughness of the first surface 11 is R 1 , where 0.01 microns ≤ R 1 ≤ 4 microns.
[0037] Preferably, the roughness R of the first surface 11 1It can be any value between 0.01 μm and 4 μm. For example, it can be 0.01 μm, 0.02 μm, 0.03 μm, 0.04 μm, 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.5 μm, 2.0 μm, 2.5 μm, 3.0 μm, 3.5 μm, 4 μm, etc. Users can select and set according to their needs, and no specific limitation is made here.
[0038] By controlling the roughness R of the first surface 11 1 With the above limitations, it can effectively bond with the first active material layer 2 with a particle size range of 3.5 μm to 4.5 μm, further enhancing the adhesion and fixation of the first active material layer 2 to the current collector 1 and preventing the first active material layer 2 from detaching from the current collector 1.
[0039] In one embodiment, 0.1 μm ≤ R 1 ≤ 3.5 μm.
[0040] Preferably, by further controlling the roughness R of the first surface 11 1 The particle size range of the first surface 11 can be further optimized, making the adhesion between the first active material layer 2 and the current collector 1 more stable and the anti-detachment effect more ideal.
[0041] In one embodiment, the electrode sheet further includes a second active material layer 3 disposed on the first active material layer 2. The first active material layer 2 is located between the current collector 1 and the second active material layer 3, and the particle size of the particles in the second active material layer 3 is g 2 where 1 μm ≤ g 2 ≤ 2.5 μm.
[0042] Preferably, the second active material layer 3 is coated on the surface of the first active material layer 2 facing away from the current collector 1 to form a double-layer active material layer structure. Specifically, the particle size g of the particles in the second active material layer 3 2 is smaller than the particle size g of the particles in the first active material layer 2 1 .
[0043] More preferably, the particle size g of the particles in the first active material layer 3 2It can be any value between 1 μm and 2.5 μm, such as 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2.0 μm, 2.1 μm, 2.2 μm, 2.3 μm, 2.4 μm, 2.5 μm, etc. Users can select and set according to their needs, and no specific limitation is made here.
[0044] By respectively making the above limitations on the particle sizes of the particles in the first active material layer 2 and the second active material layer 3, the particles in the first active material layer 2 can be firmly embedded into the first surface 11, enhancing the bonding and fixation between the first active material layer 2 and the current collector 1 and facilitating the diffusion of lithium ions, improving the cycle stability of the battery. At the same time, the surface area of contact between the second active material layer 3 and the electrolyte can be increased, improving the volume capacity and energy density of the electrode sheet.
[0045] In one embodiment, the peel strength between the first active material layer 2 and the current collector 1 is σ, where 4 N / m ≤ σ ≤ 80 N / m.
[0046] By making the above limitation on the particle size of the first active material layer 2, the bonding force between the first active material layer 2 and the current collector 1 can be significantly improved, so that the peel strength σ between the first active material layer 2 and the current collector reaches between 4 N / m and 80 N / m, effectively preventing the first active material layer 2 from detaching from the current collector 1.
[0047] Preferably, σ can be any value between 4 N / m and 80 N / m, such as 4 N / m, 5 N / m, 6 N / m, 7 N / m, 8 N / m, 9 N / m, 10 N / m, 15 N / m, 20 N / m, 25 N / m, 30 N / m, 35 N / m, 40 N / m, 45 N / m, 50 N / m, 55 N / m, 60 N / m, 65 N / m, 70 N / m, 75 N / m, 80 N / m, etc. Users can select and set according to their needs, and no specific limitation is made here.
[0048] In one embodiment, the depth h at which the first active material layer 2 is embedded in the current collector 1 satisfies 0.1 μm ≤ h ≤ 5 μm, as Figure 2 shown.
[0049] Preferably, the depth h of the first active material layer 2 embedded in the current collector 1 can be any value between 0.1 μm and 5 μm, such as 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.5 μm, 2.0 μm, 2.5 μm, 3.0 μm, 3.5 μm, 4.0 μm, 4.5 μm, 5.0 μm, etc. The user can select and set according to needs, and no specific limitation is made here.
[0050] By limiting the particle size of the first active material layer 2 within the above range, the depth h of the first active material layer 2 embedded in the current collector 1 can reach between 0.1 μm and 5 μm, thereby significantly enhancing the adhesion between the first active material layer 2 and the current collector 1 and preventing the first active material layer 2 from detaching from the current collector 1.
[0051] Specifically, the embedding depth h is the maximum depth range in which the first active material layer 2 is recessed inward from the surface of the current collector 1.
[0052] In one embodiment, the porosity of the first active material layer 2 is p 1 , where 25% ≤ p 1 ≤ 35%.
[0053] Preferably, the porosity p of the first active material layer 2 1 can be any value between 25% and 35%, such as 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, etc. The user can select and set according to needs, and no specific limitation is made here.
[0054] By limiting the particle size of the first active material layer 2 within the above range, the porosity of the first active material layer 2 can reach between 25% and 25%, thereby not only enhancing the adhesion between the first active material layer 2 and the current collector 1, but also facilitating the passage of lithium ions and improving the electrical performance.
[0055] In one embodiment, the porosity of the second active material layer 2 is p 2 , where 20% ≤ p 2 ≤ 30%.
[0056] Preferably, the porosity p of the second active material layer 2 2 can be any value between 20% and 30%, such as 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, etc. The user can select and set according to needs, and no specific limitation is made here.
[0057] By limiting the particle size of the second active material layer 2 within the above range, the porosity of the second active material layer 2 can reach 20% to 30%. Thus, not only the contact area with the electrolyte is increased, but also the electrical properties can be improved.
[0058] In one embodiment, the thickness of the first active material layer 2 is t 1 , where 1 μm ≤ t 1 ≤ 100 μm.
[0059] Preferably, the thickness t of the first active material layer 2 1 can be any value between 1 μm and 100 μm, such as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, etc. The user can select and set according to needs, and no specific limitation is made here.
[0060] Limiting the thickness of the first active material layer 2 between 1 μm and 100 μm can, on the one hand, prevent the first active material layer 2 from being too thick, which may affect the lithium-ion penetration performance and internal resistance, and on the other hand, prevent the first active material layer 2 from being too thin, which may increase the process difficulty and affect the energy density of the battery. Therefore, the limitation within the above range can optimize the first active material layer 2 to make it in the most ideal state.
[0061] More preferably, 70 μm ≤ t 1 ≤ 100 μm.
[0062] The limitation within the above range can further optimize the ideal state of the first active material layer 2.
[0063] In one embodiment, the thickness of the second active material layer 3 is t 2 , where 1 μm ≤ t 2 ≤ 100 μm.
[0064] Preferably, the thickness t of the second active material layer 3 2 can be any value between 1 μm and 100 μm, such as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, etc. The user can select and set according to needs, and no specific limitation is made here.
[0065] The thickness of the second active material layer 3 is defined to be between 1 μm and 100 μm. On the one hand, it can prevent the second active material layer 3 from being too thick, which may affect the lithium-ion penetration performance and internal resistance. On the other hand, it can prevent the second active material layer 3 from being too thin, which may increase the process difficulty and affect the energy density of the battery. Therefore, the limitation of the above range can optimize the second active material layer 3 to make it in the most ideal state.
[0066] More preferably, 70 μm ≤ t 2 ≤ 100 μm.
[0067] The limitation of the above range can further optimize the ideal state of the second active material layer 3.
[0068] On the other hand, the present invention also provides a battery, and the battery includes the electrode sheet of any one of the above.
[0069] Those skilled in the art can understand that although some of the embodiments described herein include certain features included in other embodiments rather than other features, the combination of the features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, in the claims of the present application, any one of the claimed embodiments can be used in any combination.
[0070] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present invention.
Claims
1. A pole piece, characterized in that: The pole piece includes a current collector and a first active material layer. The current collector includes a first surface. The first active material layer is arranged on the first surface. The particle size of particles in the first active material layer is g1, wherein 3.5 microns ≤ g1 ≤ 4.5 microns.
2. The pole piece according to claim 1, characterized in that: The roughness of the first surface is R1, wherein 0.01 micrometers ≤ R1 ≤ 4 micrometers.
3. The pole piece according to claim 2, characterized in that: 0.1 micron ≤ R1 ≤ 3.5 micron.
4. The pole piece according to claim 1, characterized in that: The pole piece also includes a second active material layer arranged on the surface of the first active material layer, the first active material layer is arranged between the current collector and the second active material layer, and the particle size of particles in the second active material layer is g2, wherein 1 micron≤g2≤2.5 microns.
5. The pole piece according to claim 1, characterized in that: The peel strength between the first active material layer and the current collector is σ, wherein 4 N / m≤σ≤80 N / m.
6. The pole piece according to claim 1, characterized in that: The first active material layer is embedded in the current collector to a depth of h, wherein 0.1 micrometers ≤ h ≤ 5 micrometers.
7. The pole piece according to claim 1, characterized in that: The porosity of the first active material layer is p1, wherein 25%≤p1≤35%.
8. The pole piece according to claim 4, characterized in that: The porosity of the second active material layer is p2, wherein 20%≤p2≤30%.
9. The pole piece according to claim 4, characterized in that: The thickness of the first active material layer is t1, wherein 1 micrometer ≤ t1 ≤ 100 micrometers; and / or the thickness of the second active material layer is t2, wherein 1 micrometer ≤ t2 ≤ 100 micrometers.
10. A battery, characterized in that: A pole piece comprising any one of claims 1 to 9.