Pole piece and battery

Abstract

The utility model relates to the technical field of new energy, particularly provides a pole piece and a battery, and aims to solve the problems of high cost and low energy density of a battery cell caused by the conventional pole piece. Therefore, the pole piece comprises a current collector and a first active material layer, the current collector comprises a first surface, the first active material layer is attached to the first surface, the roughness of the first surface is R1, and R1 is larger than or equal to 0.1 micrometer and smaller than or equal to 3.5 micrometers. According to the utility model, the current collector can be stably bonded with the active material layers, so that the long-term cycling stability and high-rate performance of the battery are ensured, and meanwhile, a bottom coating layer is not required to be arranged between the current collector and the first active material layer, so that the cost can be remarkably reduced, and the energy density of the battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy, and specifically provides a pole piece and a battery. Background Art

[0002] With the improvement of people's living standards and the strengthening of environmental awareness, new energy vehicles have gradually entered the homes of ordinary people, and lithium batteries, as the core components of new energy vehicles, have also developed rapidly.

[0003] The pole piece is an important component of lithium batteries. The existing pole piece includes a current collector and an active material layer attached to the current collector. The current collector is usually a smooth foil. However, the particle size of the particles in the active material layer is usually 1 micron to 2.5 microns. The particle size distribution range is narrow and the compaction density is low. After the active material is rolled on the current collector, it has poor contact with the current collector, resulting in poor adhesion between the active material layer and the current collector, and a large contact resistance between the active material layer and the current collector, which affects the long-term cycle stability and high-rate performance of the lithium battery. Therefore, in order to improve the above problems, a primer layer is usually added between the smooth foil and the active material layer. However, the primer layer will increase the cost and reduce the energy density of the battery cell, affecting the market competitiveness of the product.

[0004] Therefore, this field needs a new technical solution to solve the above problems. Utility Model Content

[0005] The utility model aims to solve the above technical problem, that is, to solve the problem that the existing pole piece contains a bottom coating, which leads to high cost and low energy density of the battery cell.

[0006] In a first aspect, the utility model provides a pole piece, including a current collector and a first active material layer, the current collector includes a first surface, the first active material layer is attached to the first surface, the roughness of the first surface is R1, wherein 0.1 micron ≤ R1 ≤ 3.5 microns.

[0007] When the above technical solution is adopted, by limiting the roughness range of the first surface of the current collector, the active material layer and the current collector can be more firmly bonded, the stability of the structure is enhanced, and the long-term cycle stability and high-rate performance of the battery are ensured. At the same time, there is no need to set a primer layer between the current collector and the first active material layer, which can significantly reduce costs and improve the energy density of the battery.

[0008] In the preferred technical solution of the above-mentioned pole piece, the particle size of the first active material layer is g, wherein 1 micron≤g≤10 microns.

[0009] In the preferred technical solution of the above-mentioned pole piece, the peel strength between the first active material layer and the current collector is σ, wherein 4N / m≤σ≤80N / m.

[0010] In the preferred technical solution of the above-mentioned pole piece, the thickness of the current collector is t1, wherein 4.5 microns ≤ t1 ≤ 20 microns.

[0011] In the preferred technical solution of the above-mentioned pole piece, the thickness of the first active material layer is t2, wherein 70 microns ≤ t2 ≤ 100 microns.

[0012] In the preferred technical solution of the above-mentioned pole piece, the width of the first active material layer that has been removed is w, wherein 10 micrometers ≤ w ≤ 200 micrometers.

[0013] In the preferred technical solution of the above-mentioned pole piece, the area of ​​the first active material layer in contact with the first surface is S1, and the area of ​​the first surface is S2, wherein 80%≤S1 / S2≤99%.

[0014] In a preferred technical solution of the above-mentioned pole piece, the current collector further includes a second surface, and the pole piece further includes a second active material layer, and the second active material layer is attached to the second surface.

[0015] In the preferred technical solution of the above-mentioned pole piece, the roughness of the second surface is R2, wherein 0.1 micrometer ≤ R2 ≤ 3.5 micrometers.

[0016] In a second aspect, the utility model further provides a battery, comprising the above-mentioned pole piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings, in which:

[0018] Figure 1 It is a three-dimensional diagram of the current collector of the utility model;

[0019] Figure 2 It is a cross-sectional view of the pole piece of the utility model.

[0020] List of reference numerals:

[0021] 1. Current collector; 11. First surface; 12. Second surface; 2. First active material layer. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles 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 "inside", "outside", "upper", "lower", "top", "bottom", "left", "right", "front", "back" and other terms indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0024] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "set", "connect", and "install" 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, see first Figure 1 and Figure 2 , Figure 1 It is a three-dimensional diagram of the current collector of the utility model. Figure 2 It is a cross-sectional view of the pole piece of the utility model.

[0026] like Figure 1 and Figure 2 As shown, the pole piece of the utility model comprises a current collector 1 and a first active material layer 2 arranged on one side of the current collector 1 .

[0027] In one embodiment, the current collector 1 can be aluminum foil or copper foil, for example, when the electrode is a positive electrode, the current collector 1 is aluminum foil; when the electrode is a negative electrode, the current collector 1 is copper foil. The user can set it as needed and no specific limitation is made here.

[0028] Furthermore, the current collector 1 may be a rectangular parallelepiped or a polygon. In the present embodiment, the current collector 1 is a rectangular parallelepiped.

[0029] Furthermore, the current collector 1 includes a first surface 11, which is an end surface in the thickness direction of the current collector 1, that is, the first surface 11 is a surface with the largest area of ​​the current collector 1. The first active material layer 2 is coated on the first surface 11, so that the first active material layer 2 and the current collector 1 can be bonded and fixed.

[0030] In one embodiment, in order to achieve stable adhesion between the current collector 1 and the first active material layer 2 , the roughness of the first surface 11 is R1, wherein 0.1 micrometers ≤ R1 ≤ 3.5 micrometers.

[0031] Specifically, the roughness R1 of the first surface 11 is any value between 0.1 microns and 3.5 microns. For example, the roughness R1 of the first surface 11 is 0.1 microns, 0.2 microns, 0.3 microns, 0.4 microns, 0.5 microns, 1 micron, 1.5 microns, 2 microns, 2.5 microns, 3 microns, 3.5 microns, etc. The user can choose the setting as needed.

[0032] By limiting the roughness R1 of the first surface as described above, it is helpful to increase the contact area between the first active material layer 2 and the first surface 11 of the current collector 1, which not only makes the bonding force between the first active material layer 2 and the current collector 1 stronger, but also makes the first active material layer 2 less likely to fall off from the fluid 1, and reduces the internal resistance of the electrode, thereby improving the cycle stability and rate performance of the battery.

[0033] Furthermore, 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 2 such as graphite and silicon, thereby meeting different usage requirements and expanding the scope of use.

[0034] Furthermore, the first active material layer 2 may be a cuboid or a polygon, etc. Preferably, the shape of the first active material layer 2 matches the shape of the current collector 1. Therefore, the shape of the first active material layer 2 may be selected and set as required, and is not specifically limited here.

[0035] In one embodiment, the first active material layer 2 is coated on a partial area of ​​the first surface 11 .

[0036] Specifically, the area of ​​the first active material layer 2 in contact with the first surface 11 is S1, and the area of ​​the first surface 11 is S2, wherein 80%≤S1 / S2≤99%.

[0037] Specifically, the above S1 / S2 can be any value between 80% and 99%, for example, S1 / S2 is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, etc. Users can choose the setting as needed, and no specific limitation is made here.

[0038] By limiting the above range, on the one hand, it is possible to prevent the contact area between the first active material layer 2 and the current collector 1 from being too small to affect the stability of the bonding and the electrical performance of the battery, and on the other hand, it is possible to prevent the first active material layer 2 from being too large to affect the stability of the battery. Therefore, by limiting the above range, it is possible to optimize the bonding and fixing of the first active material layer 2 and the current collector 1.

[0039] In one embodiment, the peel strength between the first active material layer 2 and the current collector 1 is σ, wherein 4 N / m≤σ≤80 N / m.

[0040] Specifically, the peel strength σ between the first active material layer 2 and the current collector 1 can be any value between 4 N / m and 80 N / m. For example, σ is 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. The user can choose the setting as needed, and no specific limitation is made here.

[0041] Specifically, by limiting the roughness R1 of the first surface 11, the peel strength between the first active material layer 2 and the current collector 1 can be improved so that the peel strength is within the above range, thereby improving the structural stability between the first active material layer 2 and the current collector 1, effectively preventing the first active material layer 2 from detaching from the current collector 1, and making the bonding force between the first active material layer 2 and the current collector 1 more stable.

[0042] More specifically, the limitation of the above-mentioned peel strength range can optimize the bonding stability between the first active material layer 2 and the current collector 1, on the one hand, preventing the peel strength from being too small to cause peeling of the first active material layer 2 and the current collector 1, and on the other hand, preventing the peel strength from being too large to cause deformation of the current collector 1 or increase the process difficulty.

[0043] In one embodiment, the thickness of the current collector 1 is t1, wherein 4.5 micrometers ≤ t1 ≤ 20 micrometers.

[0044] Specifically, the thickness t1 of the current collector 1 can be any value between 4.5 microns and 20 microns, for example, t1 is 4.5 microns, 4.6 microns, 4.7 microns, 4.8 microns, 4.9 microns, 5.0 microns, 6.0 microns, 7.0 microns, 8.0 microns, 9.0 microns, 10 microns, 11 microns, 12 microns, 13 microns, 14 microns, 15 microns, 16 microns, 17 microns, 18 microns, 19 microns, 20 microns, etc. Users can choose settings as needed, and no specific limitation is made here.

[0045] More specifically, by limiting the thickness t1 of the current collector 1 to the above-mentioned range, on the one hand, it can prevent the thickness of the current collector 1 from being too small so that the roughness of the first surface 11 does not reach the range of 0.1 microns to 3.5 microns. On the other hand, it can prevent the thickness of the current collector 1 from being too large, resulting in occupying too much volume, thereby affecting the energy density of the battery, etc. Therefore, the limitation in the above-mentioned range can optimally improve the space utilization and energy density on the basis of achieving a roughness of 0.1 microns to 3.5 microns on the first surface 11, thereby optimizing the overall performance of the battery.

[0046] In one embodiment, the thickness of the first active material layer 2 is t2, wherein 70 micrometers ≤ t2 ≤ 100 micrometers.

[0047] Specifically, the thickness of the first active material layer 2 can be any value between 70 microns and 100 microns. For example, the thickness of the first active material layer 2 can be 70 microns, 75 microns, 80 microns, 85 microns, 90 microns, 95 microns, 100 microns, etc. The user can choose to set it according to needs, and no specific limitation is made here.

[0048] More specifically, the thickness of the first active material layer 2 is limited to between 70 microns and 100 microns, so that on the one hand, the first active material layer 2 can be prevented from being too thick, which will affect the lithium ion penetration performance and internal resistance, and on the other hand, the first active material layer 2 can be prevented from being too thin, which will increase the process difficulty and affect the energy density of the battery. Therefore, the limitation of the above range can optimize the first active material layer 2 and put it in the most ideal state.

[0049] In one embodiment, the width of the first active material layer 2 is w, wherein 10 micrometers ≤ w ≤ 200 micrometers.

[0050] Specifically, the drop width w can be any value between 10 microns and 200 microns, for example, 10 microns, 20 microns, 30 microns, 40 microns, 50 microns, 60 microns, 70 microns, 80 microns, 90 microns, 100 microns, 110 microns, 120 microns, 130 microns, 140 microns, 150 microns, 160 microns, 170 microns, 180 microns, 190 microns, 200 microns, etc. Users can choose the setting as needed, and no specific limitation is made here.

[0051] More specifically, by limiting the range of the roughness of the first surface 11 of the current collector 1, the adhesion between the first active material layer 2 and the current collector 1 is made more stable, thereby reducing the shedding width of the first active material layer 2, so that the shedding width w is within the above range, thereby reducing the shedding of the first active material layer 2 and improving the energy density of the battery.

[0052] In one embodiment, the particle size of the first active material layer 2 is g, wherein 1 micron≤g≤10 microns.

[0053] Specifically, the particle size g of the first active material layer 2 can be any value between 1 micron and 10 microns, for example, 1 micron, 2 microns, 3 microns, 4 microns, 5 microns, 6 microns, 7 microns, 8 microns, 9 microns, 10 microns, etc. The user can choose and set it according to needs, and no specific limitation is made here.

[0054] More specifically, the particle size of the first active material layer 2 is limited to between 1 micron and 10 microns, so that it can be better adhered to the first surface 11 with a roughness between 0.1 microns and 3.5 microns, thereby significantly increasing the adhesion between the first active material layer 2 and the current collector 1, improving the stability of the structure, and preventing the first active material layer 2 from detaching from the current collector 1.

[0055] Preferably, 1 micron ≤ g ≤ 5 microns.

[0056] More preferably, 3.5 microns ≤ g ≤ 4.5 microns.

[0057] By further optimizing the g range as described above, the bonding force between the first active material layer 2 and the current collector 1 can be further optimized, the structural stability of the first active material layer 2 and the current collector 1 can be further enhanced, and the electrical performance of the battery can be improved.

[0058] In one embodiment, the current collector 1 further includes a second surface 12 , and the pole piece further includes a second active material layer (not shown), and the second active material layer is attached to the second surface 12 .

[0059] Specifically, the second surface 12 is preferably disposed opposite to the first surface 11 , that is, the first surface 11 and the second surface 12 are two end surfaces in the thickness direction of the current collector 1 , and are also the two surfaces with the largest area of ​​the current collector 1 .

[0060] More specifically, the second active material layer is coated on the second surface 12 , so that the second active material layer is attached to the second surface 12 , thereby achieving a stable connection between the second active material layer 2 and the current collector 1 .

[0061] Preferably, the second active material layer 2 may be a cuboid or a polygon, etc. The shape of the second active material layer 2 is preferably compatible with the shape of the current collector 1 so as to maximize the space utilization and improve the energy density of the battery.

[0062] More specifically, when the electrode is a positive electrode, the material of the second active material layer 2 is a positive electrode active material such as lithium iron phosphate; when the electrode is a negative electrode, the material of the second active material layer 2 is a negative electrode active material such as graphite and silicon. Users can choose and set it according to their needs, and no specific limitation is made here.

[0063] In one embodiment, the roughness of the second surface 12 is R2, wherein 0.1 micrometers ≤ R2 ≤ 3.5 micrometers.

[0064] Specifically, the roughness R2 of the second surface 12 is any value between 0.1 microns and 3.5 microns, for example, it can be 0.1 microns, 0.2 microns, 0.3 microns, 0.4 microns, 0.5 microns, 0.6 microns, 0.7 microns, 0.8 microns, 0.9 microns, 1 micron, 1.5 microns, 2 microns, 2.5 microns, 3 microns, 3.5 microns, etc. Users can choose the setting as needed, and no specific limitation is made here.

[0065] More specifically, by limiting the roughness range of the second surface 12 , the adhesion between the current collector 1 and the second active material layer 2 can be increased to ensure the stability of the structure and prevent the two from being separated.

[0066] In other embodiments, the second surface 12 may also be a conventional smooth surface, etc. The user may select and set it according to needs, and no specific limitation is made here.

[0067] In other embodiments, the second active material layer may be a conventional active material layer, and may also have the same parameter range limitations as the first active material layer 2 . The user may select and set the parameters as required, and no specific limitations are made herein.

[0068] On the other hand, the utility model further provides a battery, which includes the above-mentioned electrode sheet.

[0069] Those skilled in the art will appreciate that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims of the present application, any one of the claimed embodiments may 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 accompanying 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 fall within the protection scope of the present invention.

Claims

1. A pole piece, characterized in that: It includes a current collector and a first active material layer. The current collector includes a first surface. The first active material layer is attached to the first surface. The roughness of the first surface is R1, wherein 0.1 micrometers ≤ R1 ≤ 3.5 micrometers.

2. The pole piece according to claim 1, characterized in that: The particle size of the first active material layer is g, wherein 1 micron≤g≤10 microns.

3. 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.

4. The pole piece according to claim 1, characterized in that: The thickness of the current collector is t1, wherein 4.5 micrometers ≤ t1 ≤ 20 micrometers.

5. The pole piece according to claim 1, characterized in that: The thickness of the first active material layer is t2, wherein 70 micrometers ≤ t2 ≤ 100 micrometers.

6. The pole piece according to claim 1, characterized in that: The first active material layer has a drop width of w, wherein 10 micrometers ≤ w ≤ 200 micrometers.

7. The pole piece according to claim 1, characterized in that: An area of ​​the first active material layer in contact with the first surface is S1, and an area of ​​the first surface is S2, wherein 80%≤S1 / S2≤99%.

8. The pole piece according to claim 1, characterized in that: The current collector further includes a second surface, and the pole piece further includes a second active material layer, and the second active material layer is attached to the second surface.

9. The pole piece according to claim 8, characterized in that: The roughness of the second surface is R2, wherein 0.1 micrometers ≤ R2 ≤ 3.5 micrometers.

10. A battery, characterized in that: A pole piece comprising any one of claims 1 to 9.

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