Battery pole piece, battery, battery pack and electric equipment

Abstract

The invention provides a battery pole piece, a battery, a battery pack and electric equipment, and relates to the technical field of batteries, and the battery pole piece comprises a current collector and an active material layer coated on at least one surface of the current collector. A plurality of first micropores and a plurality of second micropores are formed in at least the middle area of the at least one active material layer, the first micropores and the second micropores are arranged at intervals, and the aperture of the second micropores is smaller than that of the first micropores. According to the battery pole piece disclosed by the embodiment of the invention, electrolyte can be quickly diffused into the active material layer through the first micropores and the second micropores during infiltration, so that the performance of the battery is improved on the premise of ensuring the energy density.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery electrode, a battery, a battery pack and an electrical device. Background Art

[0002] As a power source for transportation vehicles, batteries are widely used in new energy vehicles.

[0003] The battery cell inside the battery is composed of multiple positive plates and multiple negative plates stacked on top of each other. With the demand for high energy density and fast charging of batteries, in related technologies, the plates in the battery are developing towards larger size and higher surface density.

[0004] However, due to the slow infiltration of the electrolyte into the electrode and the long diffusion distance, there is a risk of cyclic lithium deposition in the middle of the electrode, which makes it impossible to fully exert the battery performance. Summary of the invention

[0005] Based on this, the present application provides a battery electrode, a battery, a battery pack and an electrical device to solve the problem of slow infiltration of the electrolyte on the electrode in existing batteries.

[0006] In a first aspect, the present application provides a battery pole piece, comprising a current collector and an active material layer coated on at least one surface of the current collector;

[0007] A plurality of first micropores and a plurality of second micropores are provided in at least a middle region of at least one active material layer. The first micropores and the second micropores are arranged at intervals, and the pore diameter of the second micropores is smaller than the pore diameter of the first micropores.

[0008] In a possible implementation, the first micro-holes and the second micro-holes are arranged in a rectangular array.

[0009] In a possible implementation manner, the second microholes and the first microholes are arranged alternately.

[0010] In a possible implementation, the distance between two adjacent first micropores is 30 μm to 2000 μm, and the distance between a second micropore and an adjacent first micropore is 15 μm to 1000 μm.

[0011] In a possible implementation, the first micropores enclose a micropore region, the length of the micropore region is greater than or equal to 1 / 3 of the length of the active material layer, and the width of the micropore region is greater than or equal to 1 / 3 of the width of the active material layer.

[0012] In a possible implementation manner, there is a distance between the side of the active material layer and the adjacent first micropore or second micropore, and the distance is greater than or equal to 10 μm.

[0013] In a possible implementation manner, the pore diameter of the first micropore and / or the second micropore is 1 μm to 200 μm.

[0014] In a possible implementation manner, a depth of the first micropore and / or the second micropore is 5 μm to 200 μm.

[0015] In a possible implementation, the opening of the first microhole and / or the second microhole is larger than or equal to the bottom of the hole.

[0016] In a possible implementation, two opposite surfaces of the current collector are coated with active material layers, and both active material layers are provided with a plurality of first micropores and a plurality of second micropores.

[0017] In a possible implementation, each first micropore and each second micropore on the two active material layers pass through the current collector and are correspondingly connected.

[0018] In a second aspect, the present application further provides a battery, comprising a shell and a battery cell disposed in the shell, wherein the battery cell comprises a plurality of battery pole pieces of any one of the types provided in the first aspect.

[0019] In a third aspect, the present application also provides a battery pack comprising a plurality of batteries of any one type provided in the second aspect.

[0020] In a fourth aspect, the present application further provides an electrical device, comprising a device body, on which the battery provided in the second aspect is disposed;

[0021] Alternatively, the battery pack provided in the third aspect is arranged on the device body.

[0022] The present application provides a battery pole piece, a battery, a battery pack and an electrical device, wherein the battery pole piece includes a current collector, and an active material layer is coated on at least one surface of the current collector to form a working medium for charge and discharge, and a plurality of first micropores and a plurality of second micropores are arranged in at least a middle region of at least one active material layer so that the electrolyte can quickly diffuse into the active material layer through each first micropore and each second micropore during infiltration, and the first micropores and the second micropores are arranged at intervals, and the pore size of the second micropores is smaller than the pore size of the first micropores, so that the performance of the battery is improved while minimizing the reduction of energy density. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application 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 some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 A cross-sectional view of a battery electrode provided in an embodiment of the present application;

[0025] Figure 2 A schematic diagram of the main structure of a battery electrode provided in an embodiment of the present application;

[0026] Figure 3 for Figure 2 A partial enlarged view of point B in the middle;

[0027] Figure 4 for Figure 1 Schematic diagrams of three different cross-sectional shapes of the first micropore;

[0028] Figure 5 for Figure 1 Another cross-sectional view of the battery electrode;

[0029] Figure 6 A schematic diagram of the structure of a battery cell provided in an embodiment of the present application.

[0030] Reference numerals:

[0031] 10: Battery cell;

[0032] 100: current collector;

[0033] 200: active material layer;

[0034] 210: first micropore;

[0035] 220: Second micropore. DETAILED DESCRIPTION

[0036] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of methods and devices consistent with some aspects of the present application as detailed in the appended claims.

[0037] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0038] As mentioned in the background section, the battery is equipped with a cell, which is composed of multiple positive pole pieces and multiple negative pole pieces stacked on each other. At present, with the high energy density and fast charging requirements of batteries, the battery pole pieces are developing in the direction of large size and high surface density. When adding electrolyte or in the process of charging and discharging, the large area of ​​the battery pole piece can easily lead to slow electrolyte infiltration speed on it, and the electrolyte diffusion distance is long. In particular, there is a risk of cyclic lithium precipitation in the middle part. The high tortuosity pole piece makes the lithium ion diffusion ability poor, and it is impossible to effectively give full play to the battery power and dynamic performance, and the consistency is poor.

[0039] In view of the above problems existing in the prior art, the present application provides a battery pole piece, a battery, a battery pack and an electrical device. The battery pole piece provided in the present application includes a current collector, and an active material layer is coated on at least one surface of the current collector to form a working medium for charge and discharge, and a plurality of first micropores and a plurality of second micropores are arranged in at least the middle area of ​​at least one active material layer, so that the electrolyte can quickly diffuse into the active material layer through each first micropore and each second micropore during infiltration, and the first micropore and the second micropore are arranged at intervals, and the aperture of the second micropore is smaller than the aperture of the first micropore, so that the performance of the battery is improved while minimizing the reduction of energy density.

[0040] The technical solution of the present application is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0041] First, refer to Figure 1-Figure 5 As shown, an embodiment of the present application provides a battery electrode, including a current collector 100 and an active material layer 200 coated on at least one surface of the current collector 100 .

[0042] A plurality of first micropores 210 and a plurality of second micropores 220 are disposed in at least a central region of at least one active material layer 200 . The first micropores 210 and the second micropores 220 are arranged at intervals. The pore diameter of the second micropores 220 is smaller than that of the first micropores 210 .

[0043] In this embodiment, the current collector 100 is used to collect the current generated by the active material layer 200 so as to form a larger current for external output. It can be a rectangular sheet structure. In lithium-ion batteries, it is mainly a metal foil, such as copper foil and aluminum foil. For example, the current collector 100 in the positive electrode sheet is usually aluminum foil, and the current collector 100 in the negative electrode sheet is usually copper foil. Of course, the current collector 100 may also include a pole ear located on one side.

[0044] The active material layer 200 may be coated on one surface of the current collector 100, or on both surfaces. For the positive electrode plate, the active material layer 200 thereon may include at least one of the following substances: lithium-containing phosphates with an olivine structure, lithium transition metal oxides and their respective modified compounds. Among them, the lithium-containing phosphates with an olivine structure may include but are not limited to lithium iron phosphate (such as LiFePO4, referred to as LFP), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, lithium iron manganese phosphate and carbon composite material. The active material of the positive electrode plate is not limited to the above.

[0045] For the negative electrode plate, the active material layer 200 thereon may include at least one of artificial graphite, natural graphite, mesophase carbon microspheres, hard carbon, soft carbon, silicon, silicon oxygen, silicon carbon and silicon alloy. Moreover, the electrolyte used in the battery may include an electrolyte salt and a solvent, and the electrolyte salt includes: at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl imide), lithium bis(trifluoromethanesulfonyl imide), lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate and lithium tetrafluorooxalate phosphate, and the electrolyte of the electrolyte is not limited to any of the above.

[0046] Specifically, Figure 2 As shown, at least the middle region (eg Figure 2 As shown in the area A in FIG. 1 , a plurality of first micropores 210 and a plurality of second micropores 220 are provided. The first micropores 210 and the second micropores 220 may be round holes, conical holes, special-shaped holes, etc. The first micropores 210 and the second micropores 220 may be arranged in an array, staggered, etc. in the active material layer 200. The first micropores 210 and the second micropores 220 may or may not penetrate the current collector 100. Of course, the first micropores 210 and the second micropores 220 may also be distributed throughout the active material layer 200, depending on actual needs.

[0047] In this way, when the electrolyte diffuses in the active material layer 200, it can diffuse radially along each first micropore 210 and each second micropore 220, respectively, so as to accelerate the infiltration speed during the electrolyte filling process. At the same time, the presence of micropores also increases the surface area of ​​the active material in the active material layer 200. The micropores have a certain depth, and the straight-through method shortens the diffusion distance of lithium ions, reduces the diffusion impedance of lithium ions, and is conducive to fast charging of the battery. During the charging and discharging process of the battery, the active material swells, causing the volume of the pole piece to expand, which is prone to defects such as active material peeling. The presence of micropores allows the expansion stress to be evenly released, reducing the defects of the pole piece caused by expansion.

[0048] Moreover, the aperture of the second micropore 220 is set smaller than the aperture of the first micropore 210. The electrolyte mainly accelerates the infiltration through the adjacent first micropore 210, and the second micropore 220 compensates the infiltration speed of the area far from the first micropore 210, so that the infiltration speed of each place is basically the same, and the electrolyte diffusion and the solvent distribution during the charge and discharge process are better and evenly diffused, avoiding or reducing the phenomenon of "empty area".

[0049] It is worth noting that, compared with setting all micropores with the same pore size, by controlling the pore size of the second micropore 220 to be smaller than the pore size of the first micropore 210, the material loss of the active material layer 200 can be minimized, thereby improving the performance of the battery while minimizing the reduction of energy density.

[0050] Therefore, the battery electrode provided in the embodiment of the present application includes a current collector 100, and an active material layer 200 is coated on at least one surface of the current collector 100 to form a working medium for charge and discharge, and a plurality of first micropores 210 and a plurality of second micropores 220 are arranged in at least the middle area of ​​at least one active material layer 200, so that the electrolyte can quickly diffuse into the active material layer 200 through each first micropore 210 and each second micropore 220 during infiltration, and the first micropore 210 and the second micropore 220 are arranged at intervals, and the pore size of the second micropore 220 is smaller than the pore size of the first micropore 210, so that the performance of the battery is improved while minimizing the reduction of energy density.

[0051] In a possible design, each of the first micro-holes 210 and each of the second micro-holes 220 are arranged in a rectangular array, and the second micro-holes 220 and the first micro-holes 210 are arranged alternately.

[0052] Specifically, Figure 2As shown, each first micropore 210 and each second micropore 220 are distributed along the length and width direction of the current collector 100, respectively, so as to form a rectangular array. Moreover, each second micropore 220 and each first micropore 210 are staggered with each other. For example, a line connecting every four first micropores 210 can form a minimum rectangle, and the center of the minimum rectangle corresponds to a second micropore 220. In this way, the infiltration and diffusion of the electrolyte are more uniform, and the processing of the micropores is also convenient.

[0053] Furthermore, in this embodiment, the distance between two adjacent first microholes 210 is 30 μm to 2000 μm, and the distance between the second microhole 220 and the adjacent first microhole 210 is 15 μm to 1000 μm.

[0054] Specifically, combined Figure 2 , Figure 3 As shown, the distances a1 and a2 between two adjacent first micropores 210 are 30 μm to 2000 μm, and the distances b1 and b2 between the second micropore 220 and the adjacent first micropore 210 are 15 μm to 1000 μm. The specific values ​​of a1, a2, b1, and b2 can be determined according to actual processing requirements and are not specifically limited in this embodiment.

[0055] Furthermore, in this embodiment, each first micropore 210 encloses a micropore region A, the length of the micropore region A is greater than or equal to 1 / 3 of the length of the active material layer 200 , and the width of the micropore region is greater than or equal to 1 / 3 of the width of the active material layer 200 .

[0056] Specifically, Figure 2 As shown, the length of the active material layer 200 is L1, and the width is L2. Correspondingly, the side length of the micropore region A along the length direction of the active material layer 200 is l1, and the side length along the length direction of the active material layer 200 is l2, l1≥L1 / 3, l2≥L2 / 3, so that the micropores cover the active material layer 200 as much as possible. Among them, the specific values ​​of l1, l2, L1, and L2 can be determined according to actual processing requirements, and are not specifically limited in this embodiment.

[0057] Furthermore, in this embodiment, there is a distance between the side of the active material layer 200 and the adjacent first micropore 210 or second micropore 220 , and the distance is greater than or equal to 10 μm.

[0058] Specifically, Figure 3 As shown, there are spacings c1 and c2 between the side of the active material layer 200 and the center of the adjacent first micropore 210, and c1 and c2 are greater than or equal to 10 μm to avoid micropore processing failure. The specific values ​​of c1 and c2 can be determined according to actual processing requirements and are not specifically limited in this embodiment.

[0059] In order to arrange the micropores reasonably, in this embodiment, the pore diameter of the first micropore 210 and / or the second micropore 220 is 1 μm to 200 μm.

[0060] Specifically, Figure 3 As shown, the aperture of the first micropore 210 is The second micropore 220 has a diameter of 1 μm to 200 μm. is 1 μm to 200 μm. Smaller than the aperture of the first micropore 210 That is, for The specific value of can be determined according to actual processing requirements and is not specifically limited in this embodiment.

[0061] Further, in this embodiment, the depth of the first microhole 210 and / or the second microhole 220 is 5 μm to 200 μm.

[0062] Specifically, Figure 4 As shown, the depth h of the first micropore 210 and / or the second micropore 220 is 5 μm to 200 μm. The depth h of each first micropore 210 and each second micropore 220 can be the same or different. The specific value of the depth h can be determined according to actual processing requirements and is not specifically limited in this embodiment.

[0063] Furthermore, in this embodiment, the opening of the first microhole 210 and / or the second microhole 220 is greater than or equal to the bottom of the hole.

[0064] Specifically, continue as Figure 4 As shown, that is, the first micropore 210 or the second micropore 220 can be a cylindrical hole, an inverted trapezoidal hole, an inverted conical hole, etc. It should be noted that the specific form of the micropore is related to the processing method, which includes but is not limited to laser etching, mechanical mold processing, pore formation, etc.

[0065] In some embodiments, two opposite surfaces of the current collector 100 are coated with active material layers 200 , and a plurality of first micropores 210 and a plurality of second micropores 220 are disposed on the two active material layers 200 .

[0066] Such settings, such as Figure 5 As shown, a faster infiltration speed is obtained in both the upper and lower active material layers 200 to ensure product consistency.

[0067] Furthermore, in this embodiment, each first micropore 210 and each second micropore 220 on the two active material layers 200 passes through the current collector 100 and are correspondingly connected.

[0068] Specifically, continue as Figure 5As shown, the first micropores 210 in the upper active material layer 200 are aligned with the first micropores 210 in the lower active material layer 200, and are connected through the current collector 100. Correspondingly, the second micropores 220 in the upper active material layer 200 are aligned with the second micropores 220 in the lower active material layer 200, not shown in the figure, and are connected through the current collector 100. In this way, the processing of each micropore is facilitated.

[0069] In a second aspect, an embodiment of the present application further provides a battery, including a shell and a battery cell 10 disposed in the shell, wherein the battery cell includes a plurality of battery pole pieces provided by any of the above embodiments.

[0070] Specifically, Figure 6 As shown, the battery cell 10 is formed by stacking or winding a plurality of battery pole pieces, including a positive pole piece and a negative pole piece. It should be noted that a diaphragm is required between two adjacent pole pieces. The number of battery pole pieces can be determined according to actual needs and is not specifically limited in this embodiment.

[0071] The shell is used to encapsulate the battery cell 10, and its shape can be rectangular, cylindrical, etc., with a receiving cavity inside for receiving components such as the battery cell. For a rectangular shell, the battery pole pieces inside are stacked on each other. For a cylindrical shell, the battery pole pieces inside are formed by winding.

[0072] Of course, other necessary components, such as explosion-proof valves, poles, etc., need to be provided on the inside or outside of the battery shell. The specific necessary components, shapes, sizes, etc. of the battery can be determined according to actual needs and are not excessively restricted in this embodiment.

[0073] The battery provided in the embodiment of the present application is configured with a battery pole piece, which includes a current collector 100, and an active material layer 200 is coated on at least one surface of the current collector 100 to form a working medium for charge and discharge, and a plurality of first micropores 210 and a plurality of second micropores 220 are arranged in at least the middle area of ​​at least one active material layer 200, so that the electrolyte can quickly diffuse into the active material layer 200 through each first micropore 210 and each second micropore 220 during infiltration, and the first micropore 210 and the second micropore 220 are arranged at intervals, and the pore size of the second micropore 220 is smaller than the pore size of the first micropore 210, so that the performance of the battery is improved while minimizing the reduction of energy density.

[0074] In a third aspect, an embodiment of the present application further provides a battery pack comprising multiple batteries provided by any of the above embodiments.

[0075] The battery pack provided in the embodiment of the present application is configured with a battery, wherein the battery includes a plurality of battery pole pieces, and the battery pole piece includes a current collector 100. An active material layer 200 is coated on at least one surface of the current collector 100 to form a working medium for charge and discharge. A plurality of first micropores 210 and a plurality of second micropores 220 are arranged in at least a central region of at least one active material layer 200 so that the electrolyte can quickly diffuse into the active material layer 200 through each of the first micropores 210 and each of the second micropores 220 during infiltration, and the first micropores 210 and the second micropores 220 are arranged at intervals, and the pore size of the second micropores 220 is smaller than the pore size of the first micropores 210, so that the performance of the battery is improved while minimizing the reduction of energy density.

[0076] In a fourth aspect, an embodiment of the present application further provides an electrical device, including a device body, on which is disposed a battery or a battery pack provided in any of the above embodiments.

[0077] The vehicle provided in the embodiment of the present application is prepared by the above-mentioned battery or battery pack, the battery includes a plurality of battery pole pieces, the battery pole piece includes a current collector 100, and an active material layer 200 is coated on at least one surface of the current collector 100 to form a working medium for charge and discharge, and a plurality of first micropores 210 and a plurality of second micropores 220 are arranged in at least the middle area of ​​at least one active material layer 200, so that the electrolyte can quickly diffuse into the active material layer 200 through each first micropore 210 and each second micropore 220 during infiltration, and the first micropore 210 and the second micropore 220 are arranged at intervals, and the pore size of the second micropore 220 is smaller than the pore size of the first micropore 210, so that the performance of the battery is improved while minimizing the reduction of energy density.

[0078] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the application disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the claims.

[0079] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A battery pole piece, characterized in that: It comprises a current collector (100) and an active material layer (200) coated on at least one surface of the current collector (100); At least a middle region of at least one of the active material layers (200) is provided with a plurality of first micropores (210) and a plurality of second micropores (220), the first micropores (210) and the second micropores (220) are arranged at intervals, and the pore diameter of the second micropores (220) is smaller than the pore diameter of the first micropores (210).

2. The battery electrode according to claim 1, characterized in that: Each of the first micropores (210) and each of the second micropores (220) are arranged in a rectangular array.

3. The battery pole piece according to claim 2, characterized in that: The second micropores (220) and the first micropores (210) are arranged alternately.

4. The battery pole piece according to claim 3, characterized in that: The distance between two adjacent first micropores (210) is 30 μm to 2000 μm, and the distance between the second micropore (220) and the adjacent first micropore (210) is 15 μm to 1000 μm.

5. The battery pole piece according to claim 2, characterized in that: Each of the first micropores (210) forms a micropore region, the length of the micropore region is greater than or equal to 1 / 3 of the length of the active material layer (200), and the width of the micropore region is greater than or equal to 1 / 3 of the width of the active material layer (200).

6. The battery pole piece according to claim 5, characterized in that: There is a distance between the side of the active material layer (200) and the adjacent first micropore (210) or the second micropore (220), and the distance is greater than or equal to 10 μm.

7. The battery pole piece according to any one of claims 1 to 6, characterized in that: The pore size of the first micropore (210) and / or the second micropore (220) is 1 μm to 200 μm.

8. The battery pole piece according to claim 7, characterized in that: The depth of the first micropore (210) and / or the second micropore (220) is 5 μm to 200 μm.

9. The battery pole piece according to claim 7, characterized in that: The opening of the first micropore (210) and / or the second micropore (220) is larger than or equal to the bottom of the pore.

10. The battery pole piece according to claim 7, characterized in that: The active material layer (200) is coated on two opposite surfaces of the current collector (100), and a plurality of the first micropores (210) and a plurality of the second micropores (220) are provided on both active material layers (200).

11. The battery pole piece according to claim 10, characterized in that: Each of the first micropores (210) and each of the second micropores (220) on the two active material layers (200) passes through the current collector (100) and are connected to each other accordingly.

12. A battery, characterized in that: It comprises a shell and a battery cell (10) arranged in the shell, wherein the battery cell (10) comprises a plurality of battery pole pieces according to any one of claims 1 to 11.

13. A battery pack, characterized in that: Comprising a plurality of batteries as claimed in claim 12.

14. An electrical device, characterized in that: comprising a device body, on which the battery according to claim 12 is arranged; Alternatively, a battery pack as claimed in claim 13 is disposed on the device body.

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