Pole piece and battery

Abstract

The utility model discloses a pole piece which comprises a current collector, an active material layer arranged on the surface of the current collector and a through hole penetrating through the current collector and the active material layer. Therefore, the pole piece is provided with the through hole penetrating through the current collector and the active material layer arranged on the surface of the current collector, and when electrolyte is injected into the battery, the through hole can retain part of the electrolyte, so that the electrolyte retention capacity can be improved; and moreover, the through holes are formed, so that the overall contact area between the pole piece and electrolyte can be increased, the electrolyte can absorb the pole piece more easily, and the wettability can be improved. In addition, the through holes are formed to improve the liquid retention capacity, so that ion transmission in the battery can be improved, and the cycle life of the lithium battery can be prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a pole piece and a battery provided with the pole piece. Background Art

[0002] In order to improve the energy density of lithium-ion batteries, the battery pole pieces are gradually developing towards high compaction and thick electrodes. In the prior art, the energy density of the battery is improved by highly coated pole pieces. However, since the highly coated pole pieces are thicker, the electrolyte is not easy to penetrate, and the amount of liquid in the pole pieces is insufficient, which leads to an increase in the diffusion distance of lithium ions, making it impossible for the electrolyte to contact some active materials inside the pole pieces, thus seriously affecting the capacity and cycle life of the battery. At the same time, the wetting problem has always been an important issue affecting the performance of lithium-ion batteries, which will affect the battery's rate, storage, cycle and other performance. Utility Model Content

[0003] In view of this, the purpose of the utility model is to provide a pole piece and a battery. By providing a through hole penetrating the current collector and the active material layer provided on the surface of the current collector, when the electrolyte is injected into the battery, the through hole can retain a part of the electrolyte, thereby increasing the amount of electrolyte retained.

[0004] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0005] A pole piece comprises a current collector, an active material layer arranged on the surface of the current collector, and a through hole penetrating the current collector and the active material layer.

[0006] Optionally, in the above-mentioned pole piece, a hole area is provided with a plurality of the through holes and a non-hole area is provided with no through holes; the distance between the boundary of the hole area and the boundary of the active coating close to it is 0.2 mm to 15 mm;

[0007] Wherein, the non-hole area is arranged at both ends of the pole piece along the first direction;

[0008] Alternatively, the non-hole area is arranged on at least one side of the pole piece along a second direction, and the second direction is perpendicular to the first direction.

[0009] Optionally, in the above-mentioned pole piece, a heat-affected zone is formed around the through hole, and the diameter of the heat-affected zone is 1 to 6 times the aperture of the through hole.

[0010] Optionally, in the above-mentioned pole piece, along the first direction, the center distance L1 between the adjacent through holes is 0.2 mm to 2 mm;

[0011] and / or, along the second direction, the center distance L2 between adjacent through holes is 0.2 mm to 2 mm;

[0012] And / or, along the first direction, a center distance W1 between two adjacent rows of through holes is 0-2 mm.

[0013] Optionally, in the above-mentioned pole piece, the through holes in the hole area are divided into a plurality of units, the through holes in each unit are evenly arranged along a circular trajectory, and there are common through holes between adjacent units; the radius R of the circular trajectory is 0.1 mm to 1 mm.

[0014] Optionally, in the above-mentioned pole piece, each of the units includes 3 to 10 through holes.

[0015] Optionally, in the above-mentioned electrode sheet, the weight loss rate of the current collector and the active material layer in the hole area compared with the weight loss rate of the current collector and the active material layer in the non-hole area per unit area is It is 0.5% to 1.5%.

[0016] A battery, comprising a first pole piece and a second pole piece:

[0017] The first pole piece is the pole piece mentioned above;

[0018] The second pole piece is the pole piece mentioned above.

[0019] Optionally, in the above battery, the aperture of the through hole in the first pole piece is 40 μm≤a≤120 μm;

[0020] And / or, the aperture of the through hole in the second pole piece is 15 μm≤a≤100 μm.

[0021] Optionally, in the above battery, the aperture of the first pole piece is larger than the aperture of the second pole piece;

[0022] And / or, the sum of the orthographic projection areas of the through holes in the first pole piece is greater than the sum of the orthographic projection areas of the through holes in the second pole piece.

[0023] Optionally, in the above-mentioned battery, the weight loss rate of the current collector and the active material layer in the pore area per unit area of ​​the second pole piece compared to the current collector and the active material layer in the non-pore area is smaller than the weight loss rate of the current collector and the active material layer in the pore area per unit area of ​​the first pole piece compared to the current collector and the active material layer in the non-pore area.

[0024] Optionally, in the above battery,

[0025] The contact angle θ2 of the hole area of ​​the first pole piece is reduced by 0 to 25° compared with the contact angle θ1 of the non-hole area of ​​the first pole piece;

[0026] And / or, the contact angle θ2 of the hole area of ​​the second pole piece is reduced by 0 to 15° compared with the contact angle θ1 of the non-hole area of ​​the second pole piece.

[0027] Optionally, in the above battery, the residual liquid amount in the hole area of ​​the first pole piece is greater than the residual liquid amount in the hole area of ​​the second pole piece.

[0028] Optionally, in the above battery, the ratio of the contact angle θ2 of the hole area to the contact angle θ1 of the non-hole area of ​​the same electrode is γ;

[0029]

[0030] Optionally, in the above-mentioned battery, the first pole piece and the second pole piece each include a first surface and a second surface relative to each other, the through hole passes through the first surface and the second surface, the first surface is the front side of the through hole, the second surface is the back side of the through hole, and the contact angle of the first surface is greater than the contact angle of the second surface.

[0031] Optionally, in the above battery, the difference between the contact angle of the first surface and the contact angle of the second surface in the first pole piece is 0 to 20°;

[0032] And / or, a difference between a contact angle of the first surface and a contact angle of the second surface of the second pole piece is 0-10°.

[0033] Optionally, in the above battery, in the first pole piece, the lattice vibration peak intensity ratio between the first surface and the second surface is 1.01;

[0034] The ratio of the peak intensities of the controlled lithium cobalt oxide lattice vibrations of the first surface and the second surface is in the range of 1 to 1.2.

[0035] Optionally, in the above battery, the graphite of the second pole piece has a -1 The peak intensity of the Raman peaks on the left and right is IG; at 1360cm -1 The peak intensity of the left and right Raman peaks is ID;

[0036] Wherein, ID / IG of the graphite at the through hole on the first surface of the second pole piece is β1=1.2, and β1 is between 0.5 and 1.5;

[0037] and / or, ID / IG of the graphite at the through hole on the second surface of the second pole piece is β2=0.15, and β2 is between 0.1 and 1;

[0038] Among them, β=β1 / β2, 1≤β≤15.

[0039] It can be seen from the above technical scheme that the pole piece provided by the utility model can retain a part of the electrolyte when the electrolyte is injected into the battery by setting a through hole that penetrates the current collector and the active material layer set on the surface of the current collector, thereby increasing the amount of liquid retained; and the opening of the through hole can increase the contact area between the pole piece and the electrolyte as a whole, making it easier for the electrolyte to be absorbed, so it can also improve the wettability. In addition, the part of the electrolyte retained in the through hole can make the electrolyte relatively more, and the ion impedance is relatively small. After multiple charge and discharge cycles of the battery, there is a certain loss of electrolyte. Since more electrolyte is stored in the through hole, the cycle life of the battery can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 The structure of the pole piece provided in the embodiment of the utility model is shown in FIG. Figure 1 ;

[0042] Figure 2 The structure of the pole piece provided in the embodiment of the utility model is shown in FIG. Figure 2 ;

[0043] Figure 3 Schematic diagram of the arrangement of through holes in the hole area provided by the embodiment of the utility model Figure 1 ;

[0044] Figure 4 Schematic diagram of the arrangement of through holes in the hole area provided in the embodiment of the utility model Figure 2 ;

[0045] Figure 5 Schematic diagram of the arrangement of through holes in the hole area provided by the embodiment of the utility model Figure 3 ;

[0046] Figure 6 A schematic diagram of the contact angle of the non-porous area of ​​the positive electrode provided in an embodiment of the utility model;

[0047] Figure 7 A schematic diagram of the contact angle of the positive electrode perforated area provided in an embodiment of the utility model;

[0048] Figure 8 A schematic diagram of the contact angle of the non-porous area of ​​the negative electrode provided in an embodiment of the utility model;

[0049] Fig. 9A schematic diagram of the contact angle of the negative electrode perforated area provided in an embodiment of the utility model;

[0050] Fig.10 A Raman image of the first surface of the positive electrode provided by an embodiment of the utility model;

[0051] Fig.11 A Raman image of the second surface of the positive electrode provided by an embodiment of the utility model;

[0052] Fig.12 A Raman image of the first surface of the negative electrode provided in an embodiment of the utility model;

[0053] Fig.13 This is a Raman image of the second surface of the negative electrode provided in an embodiment of the present utility model.

[0054] in:

[0055] 1-current collector, 2-active material layer, 3-through hole, 41-pore area, 42-non-pore area. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0057] In the description of the utility model, it should be noted that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the utility model product is usually placed when in use, and are only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0058] like Figures 1 to 13 As shown, an embodiment of the utility model provides a pole piece.

[0059] Firstly, the pole piece comprises a current collector 1 , an active material layer 2 arranged on the surface of the current collector 1 , and a through hole 3 penetrating the current collector 1 and the active material layer 2 .

[0060] It can be seen that the pole piece provided by the embodiment of the utility model, by setting the through hole 3 penetrating the current collector 1 and the active material layer 2 set on the surface of the current collector 1, when the electrolyte is injected into the battery, the through hole 3 can retain a part of the electrolyte, thereby increasing the amount of liquid retention; and the opening of the through hole 3 can increase the contact area between the pole piece and the electrolyte as a whole, making it easier for the electrolyte to be absorbed, so the wettability can also be improved. In addition, the part of the electrolyte retained in the through hole 3 can make the electrolyte relatively more, the ion impedance is relatively small, and the battery has a certain loss of electrolyte after multiple charge and discharge cycles. Since part of the electrolyte is stored in the through hole 3, the cycle life of the battery can be improved.

[0061] In specific implementation, it includes a hole area 41 with multiple through holes 3 and a non-hole area 42 without through holes 3; the distance between the boundary of the hole area 41 and the boundary of the active coating close to it is 0.2mm-15mm. Leaving a certain distance from the boundary can avoid the formation of a gap at the edge of the foil by the through hole 3, resulting in stress concentration and breaking of the foil, and there is a thinning area at the edge of the hole area 41 within a certain distance from the boundary of the active coating close to it. The thickness of the active coating in this area is relatively thin and the wettability is better. Among them, see Figure 2 , the non-hole area 42 is arranged at both ends of the pole piece along the first direction, which is suitable for conventional pole ears or CPT structures; or, see Figure 1 The non-hole area 42 is arranged on at least one side of the pole piece along the second direction (that is, the non-hole area 41 can be arranged on one side along the second direction, or on both sides), which is suitable for a multi-electrode structure or a laminated structure, and the second direction is perpendicular to the first direction. It should be noted that the first direction is the length direction of the pole piece, see Figure 1 The second direction is the direction of the arrow in the figure, and the second direction is the width direction of the pole piece.

[0062] In specific implementation, a heat-affected zone is formed around the through hole 3, and the diameter of the heat-affected zone is 1 to 6 times the diameter of the through hole 3. The heat-affected zone can maintain the stability of the active coating and reduce the risk of powdering of the active coating around the through hole 3.

[0063] In a specific implementation, along the first direction, the center distance L1 between adjacent through holes 3 is 0.2 mm to 2 mm; along the second direction, the center distance L2 between adjacent through holes 3 is 0.2 mm to 2 mm. Figure 3 , the through holes 3 in the hole area 41 can be arranged in a rectangular matrix structure.

[0064] For specific implementation, see Figure 4 , along the first direction, the center distance W1 between two adjacent rows of through holes 3 is 0-2 mm. On the basis of the rectangular matrix, the through holes 3 in two adjacent rows are staggered with each other.

[0065] For specific implementation, see Figure 5, the through holes 3 in the hole area 41 are divided into multiple units, the through holes 3 in each unit are evenly arranged along a circular trajectory, and there are shared through holes 3 between adjacent units; the radius R of the circular trajectory is 0.1mm to 1mm. A plum blossom array is formed. However, it is not limited to this. The specific arrangement of the through holes 3 in the hole area 41 can be specifically designed by those skilled in the art according to actual needs. In addition, adjacent units may not share the through holes 3, forming other forms of arrangement.

[0066] In a specific implementation, each unit includes 3 to 10 through holes 3, but is not limited thereto. The specific number of through holes 3 in each unit can be specifically designed by those skilled in the art according to actual needs.

[0067] In a specific implementation, the weight loss rate of the current collector 1 and the active material layer 2 in the pore area 41 compared with the weight loss rate of the current collector 1 and the active material layer 2 in the non-pore area 42 per unit area is The weight loss rate is 0.5% to 1.5%, which can avoid the weight loss rate being too large to affect the performance of the battery, and at the same time avoid the weight loss rate being too small to achieve the effect of increasing the liquid retention and wettability of the electrode.

[0068] An embodiment of the utility model provides a battery, comprising a first pole piece and a second pole piece, wherein the first pole piece is the above-mentioned pole piece, and the second pole piece is the above-mentioned pole piece.

[0069] It can be seen that the pole piece in the battery provided by the embodiment of the utility model, by setting the through hole 3 penetrating the current collector 1 and the active material layer 2 set on the surface of the current collector 1, when the electrolyte is injected into the battery, the through hole 3 can retain a part of the electrolyte, thereby increasing the amount of liquid retention; and the opening of the through hole 3 can increase the contact area between the pole piece and the electrolyte as a whole, making it easier for the electrolyte to be absorbed, so it can also improve the wettability. In addition, the part of the electrolyte retained in the through hole 3 can make the electrolyte relatively more, and the ion impedance is relatively small. After multiple charge and discharge cycles of the battery, there is a certain loss of electrolyte. Since part of the electrolyte is stored in the through hole 3, the cycle life of the battery can be improved.

[0070] In a specific implementation, the aperture of the through hole 3 in the first pole piece is 40 μm≤a≤120 μm; and / or the aperture of the through hole 3 in the second pole piece is 15 μm≤a≤100 μm.

[0071] In specific implementation, the aperture of the first pole piece is larger than the aperture of the second pole piece. The first pole piece can increase the coverage of the positive and negative electrodes and effectively reduce the risk of lithium precipitation; and / or, the sum of the orthographic projection areas of the through holes 3 in the first pole piece is larger than the sum of the orthographic projection areas of the through holes 3 in the second pole piece. While improving the wetting of the electrolyte, the amount of residual liquid is increased to prevent uneven distribution of the electrochemical reaction and drying up of the electrolyte, thereby extending the cycle life of the battery. In addition, the weight of the battery can be reduced. And the positive electrode pore area is larger than the negative electrode pore area, which is also conducive to reducing the risk of lithium precipitation.

[0072] In specific implementation, the weight loss rate of the current collector 1 and the active material layer 2 in the hole area 41 of the second pole piece per unit area compared with the current collector 1 and the active material layer 2 in the non-hole area 42 is less than the weight loss rate of the current collector 1 and the active material layer 2 in the hole area 41 of the first pole piece per unit area compared with the current collector 1 and the active material layer 2 in the non-hole area 42. This ensures that the wettability and residual liquid amount of the pole piece are effectively increased without losing too much pole piece weight, thereby improving the battery cycle performance.

[0073] In a specific implementation, the contact angle θ2 of the hole area 41 of the first pole piece is reduced by 0 to 25° compared with the contact angle θ1 of the non-hole area 42 of the first pole piece; and / or the contact angle θ2 of the hole area 41 of the second pole piece is reduced by 0 to 15° compared with the contact angle θ1 of the non-hole area 42 of the second pole piece.

[0074] In a specific implementation, the residual liquid amount in the hole area 41 of the first pole piece is greater than the residual liquid amount in the hole area 41 of the second pole piece.

[0075] In a specific implementation, the ratio of the contact angle θ2 of the hole area 41 to the contact angle θ1 of the non-hole area 42 of the same pole piece is γ, that is, γ=θ2 / θ1;

[0076]

[0077] A small contact angle can speed up the wetting of the electrolyte on the electrode surface, increase the effective reaction area on the electrode surface, facilitate the rapid diffusion of ion transport in the electrolyte, reduce the internal resistance of the battery, and improve the power performance of the battery.

[0078] In a specific implementation, the first pole piece and the second pole piece each include a first surface and a second surface relative to each other, the through hole 3 passes through the first surface and the second surface, the first surface is the front side of the through hole 3, the second surface is the back side of the through hole 3, and the contact angle of the first surface is greater than the contact angle of the second surface.

[0079] In a specific implementation, the difference between the contact angle of the first surface and the contact angle of the second surface in the first pole piece is 0-20°; and / or the difference between the contact angle of the first surface and the contact angle of the second surface in the second pole piece is 0-10°.

[0080] In a specific implementation, in the first pole piece, the lattice vibration peak intensity ratio between the first surface and the second surface is 1.01, wherein the controlled lithium cobalt oxide lattice vibration peak intensity ratio between the first surface and the second surface is 1 to 1.2, which can ensure that the lithium cobalt oxide lattice is basically not destroyed.

[0081] In specific implementation, the graphite of the second pole piece is at 1585cm -1 The peak intensity of the Raman peaks on the left and right is IG; at 1360cm -1 The peak intensity of the Raman peaks on the left and right is ID; wherein, the ID / IG of the graphite at the through hole 3 on the first surface of the second pole piece is β1=1.2, and β1 is between 0.5 and 1.5; and / or, the ID / IG of the graphite at the through hole 3 on the second surface of the second pole piece is β2=0.15, and β2 is between 0.1 and 1; wherein, β=β1 / β2, 1≤β≤15. The disorder degree of the first surface where the through hole 3 is opened in the hole region 41 is greater than that of the second surface. The increase in the disorder degree of the part is conducive to the formation of pores, channels and other structures in different orientations in the material structure, thereby increasing the ability of lithium ion extraction and insertion.

[0082] In specific implementation, after the positive and negative pole pieces are rolled, slit, and die-cut, a certain number of through holes 3 are punched on the pole piece surface by a pulsed laser, and the aperture of the hole punched on the first surface is greater than or equal to the aperture of the hole on the second surface, and the large hole in the first pole piece is larger than the large hole in the second pole piece, and the small hole in the first pole piece is larger than the small hole in the second pole piece. Punching holes on the pole piece surface is not limited to laser hole forming, and the hole forming form can be specifically designed by those skilled in the art according to actual needs.

[0083] In a specific implementation, the punched electrode is further processed into sheets, and then the sheets are wound or stacked to form a winding core or a stacked core.

[0084] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0085] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0086] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A pole piece, characterized in that: It comprises a current collector (1), an active material layer (2) arranged on the surface of the current collector (1), and a through hole (3) penetrating the current collector (1) and the active material layer (2).

2. The pole piece according to claim 1, characterized in that: It comprises a hole area (41) provided with a plurality of the through holes (3) and a non-hole area (42) without the through holes (3); the distance between the boundary of the hole area (41) and the boundary of the active material layer adjacent to it is 0.2 mm to 15 mm; Wherein, the non-hole area (42) is arranged at both ends of the pole piece along the first direction; Alternatively, the non-hole area (42) is arranged on at least one side of the pole piece along a second direction, and the second direction is perpendicular to the first direction.

3. The pole piece according to claim 1, characterized in that: A heat-affected zone is formed around the through hole (3), and the diameter of the heat-affected zone is 1 to 6 times the diameter of the through hole (3).

4. The pole piece according to claim 1, characterized in that: Along the first direction, the center distance L1 between adjacent through holes (3) is 0.2 mm to 2 mm; and / or, along the second direction, the center distance L2 between adjacent through holes (3) is 0.2 mm to 2 mm; And / or, the center distance W1 between two adjacent rows of through holes (3) is 0 to 2 mm.

5. The pole piece according to claim 2, characterized in that: The through holes (3) in the hole area (41) are divided into a plurality of units, the through holes (3) in each unit are evenly arranged along a circular trajectory, and adjacent units share the through holes (3); the radius R of the circular trajectory is 0.1 mm to 1 mm.

6. The pole piece according to claim 5, characterized in that: Each of the units comprises 3 to 10 through holes (3).

7. The pole piece according to claim 2, characterized in that: The weight loss rate of the current collector (1) and the active material layer (2) in the pore area (41) compared with the weight loss rate of the current collector (1) and the active material layer (2) in the non-pore area (42) per unit area It is 0.5% to 1.5%.

8. A battery, characterized in that: It includes a first pole piece and a second pole piece: The first pole piece is the pole piece according to any one of claims 1 to 7; The second pole piece is the pole piece described in any one of claims 1-7.

9. The battery according to claim 8, characterized in that The aperture of the through hole (3) in the first pole piece is 40 μm≤a≤120 μm; And / or, the aperture of the through hole (3) in the second pole piece is 15 μm≤a≤100 μm.

10. The battery according to claim 8, characterized in that The aperture of the first pole piece is larger than the aperture of the second pole piece; And / or, the sum of the orthographic projection areas of the through holes (3) in the first pole piece is greater than the sum of the orthographic projection areas of the through holes (3) in the second pole piece.

11. The battery according to claim 8, characterized in that The weight loss rate of the current collector (1) and the active material layer (2) in the hole area (41) of the second pole piece compared to the weight loss rate of the current collector (1) and the active material layer (2) in the non-hole area (42) per unit area is smaller than the weight loss rate of the current collector (1) and the active material layer (2) in the hole area (41) compared to the weight loss rate of the current collector (1) and the active material layer (2) in the non-hole area (42) per unit area of ​​the first pole piece.

12. The battery according to claim 8, characterized in that The contact angle θ2 of the hole region (41) of the first pole piece is reduced by 0 to 25° compared with the contact angle θ1 of the non-hole region (42) of the first pole piece; And / or, the contact angle θ2 of the hole region (41) of the second pole piece is reduced by 0 to 15° compared with the contact angle θ1 of the non-hole region (42) of the second pole piece.

13. The battery according to claim 8, characterized in that The residual liquid volume in the hole area of ​​the first pole piece is greater than the residual liquid volume in the hole area of ​​the second pole piece.

14. The battery according to claim 12, characterized in that The ratio of the contact angle θ2 of the hole area (41) to the contact angle θ1 of the non-hole area (42) of the same pole piece is γ; 15. The battery according to claim 8, characterized in that The first pole piece and the second pole piece each comprise a first surface and a second surface opposite to each other, the through hole (3) passes through the first surface and the second surface, the first surface is the front side of the through hole (3), the second surface is the back side of the through hole (3), and the contact angle of the first surface is greater than the contact angle of the second surface.

16. The battery according to claim 15, characterized in that The difference between the contact angle of the first surface and the contact angle of the second surface of the first pole piece is 0-20°; And / or, a difference between a contact angle of the first surface and a contact angle of the second surface of the second pole piece is 0-10°.

17. The battery according to claim 15, characterized in that In the first pole piece, the lattice vibration peak intensity ratio between the first surface and the second surface is 1.01; The ratio of the peak intensities of the controlled lithium cobalt oxide lattice vibrations of the first surface and the second surface is in the range of 1 to 1.

2.

18. The battery according to claim 15, characterized in that The graphite of the second pole piece has a -1 The peak intensity of the Raman peaks on the left and right is IG; at 1360cm -1 The peak intensity of the left and right Raman peaks is ID; Wherein, the ID / IG of the graphite at the through hole (3) on the first surface of the second pole piece is β1=1.2, and β1 is between 0.5 and 1.5; and / or, the ID / IG of the graphite at the through hole (3) on the second surface of the second pole piece is β2=0.15, and β2 is between 0.1 and 1; Among them, β=β1 / β2, 1≤β≤15.

Images