Battery pole piece, battery, battery pack and electric device

Abstract

The application provides a battery pole piece, a battery, a battery pack and an electric equipment, and relates to the technical field of batteries. The battery pole piece comprises a current collector and an active material layer coated on at least one surface of the current collector. At least the middle region of at least one active material layer is provided with a plurality of first micropores and a plurality of second micropores. The first micropores and the second micropores are arranged at intervals, and the pore diameter of the second micropores is smaller than that of the first micropores. According to the battery pole piece provided in the application, when the electrolyte is infiltrated, the electrolyte can quickly spread into the active material layer through the first micropores and the second micropores, and 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 technical field of batteries, in particular to a battery pole piece, a battery, a battery pack and a power consumption device. BACKGROUND

[0002] As a power source for providing power for transportation tools, a battery is widely used in new energy vehicle models.

[0003] The battery cell inside the battery is formed by the mutual superposition of a plurality of positive pole pieces and a plurality of negative pole pieces. With the demand for high energy density and fast charging of the battery, the pole piece in the battery develops in the direction of large size and high surface density in the related art.

[0004] However, due to slow infiltration of the electrolyte on the pole piece and long diffusion distance, there is a risk of cyclic lithium precipitation at the middle position of the pole piece, so that the performance of the battery cannot be fully utilized. SUMMARY

[0005] Therefore, the present application provides a battery pole piece, a battery, a battery pack and a power consumption device to solve the problem of slow infiltration of electrolyte on the pole piece in the existing battery.

[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] At least the middle region of the at least one active material layer is provided with a plurality of first micropores and a plurality of second micropores, 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, each first micropore and each second micropore is arranged in a rectangular array.

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

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

[0011] In a possible implementation, each first micropore surrounds 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, there is a spacing between the side edge of the active material layer and the adjacent first micropore or second micropore, and the spacing is greater than or equal to 10 μm.

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

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

[0015] In a possible implementation, the first micropore and / or the second micropore has a pore opening larger than or equal to a pore bottom.

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

[0017] In a possible implementation, each of the first micropores and each of the second micropores on the two active material layers penetrates through the current collector and corresponds to a communication.

[0018] In a second aspect, the application further provides a battery, comprising a shell and an electric core arranged in the shell, the electric core comprising a plurality of any one of the battery pole pieces provided in the first aspect.

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

[0020] In a fourth aspect, the application further provides an electric device, comprising a device body, the device body being provided with the battery provided in the second aspect.

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

[0022] The application provides a battery pole piece, a battery, a battery pack and an electric device. The battery pole piece comprises a current collector. An active material layer is coated on at least one surface of the current collector to form a working medium for charging and discharging. A plurality of first micropores and a plurality of second micropores are arranged in at least a middle region of the at least one active material layer, so that the electrolyte can quickly diffuse into the active material layer through the first micropores and the second micropores when the electrolyte is infiltrated. The first micropores and the second micropores are arranged at intervals, and the second micropores have a smaller pore diameter than the first micropores. The performance of the battery is improved without reducing the energy density as much as possible. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, hereinafter, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without any creative labor.

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

[0025] Figure 2 A front view structural schematic diagram of a battery pole piece provided for an embodiment of the present application;

[0026] Figure 3 A Figure 2 A local enlarged view at B;

[0027] Figure 4 A Figure 1 A schematic diagram of three different cross-sectional shapes of the first micropore;

[0028] Figure 5 A Figure 1 Another cross-sectional view of a battery pole piece;

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

[0030] Reference Signs:

[0031] 10: battery cell;

[0032] 100: current collector;

[0033] 200: active material layer;

[0034] 210: first micropore;

[0035] 220: second micropore. DETAILED DESCRIPTION

[0036] The exemplary embodiments will be described in detail herein with reference to the attached drawings. In the following description, the same numbers are used to indicate the same elements throughout the drawings. The following exemplary embodiments are not representative of all embodiments consistent with the present application. Rather, they are merely examples of methods and apparatuses consistent with some aspects of the present application, as detailed in the appended claims.

[0037] The terms "first", "second", "third", "fourth" and the like in the description and in the claims of the present application, and above-mentioned drawings, if any, are used to distinguish similar objects and are not necessarily used to describe a particular sequential or chronological order. It should be understood that the data thus used can be interchanged, where appropriate, so that the embodiments of the present application described herein can be carried out in other than the order shown or described herein. Furthermore, the terms "comprise" and "have", and any variations thereof, are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or apparatus that comprises a list of steps or units does not necessarily limit those steps or units to the clearly stated ones, but can include other steps or units that are not clearly listed or inherent to such processes, methods, products, or apparatuses.

[0038] As mentioned in the background section, the battery is internally provided with an electrode core, which is formed by mutually superimposing a plurality of positive electrode sheets and a plurality of negative electrode sheets. At present, with the demand for high energy density and fast charging of the battery, the battery electrode sheet is developing in the direction of large size and high surface density. During the injection of electrolyte or the charging and discharging process, the large area of the battery electrode sheet easily leads to slow infiltration of the electrolyte thereon, long diffusion distance of the electrolyte, and especially, there is a risk of cyclic lithium precipitation in the middle position part. The high tortuosity of the electrode sheet makes the lithium ion diffusion ability poor, and the battery power and kinetic performance cannot be effectively and fully utilized, and the consistency is poor.

[0039] In view of the above problems existing in the prior art, the present application provides a battery electrode sheet, a battery, a battery pack and an electrical equipment. The battery electrode sheet provided by the present application comprises a current collector. An active material layer is coated on at least one surface of the current collector to form a working medium for charging and discharging. A plurality of first micropores and a plurality of second micropores are arranged in at least the middle region of the at least one active material layer, so that the electrolyte can quickly diffuse into the active material layer through the first micropores and the second micropores when infiltrating, and the first micropores and the second micropores are arranged at intervals, and the pore diameter of the second micropores is smaller than that of the first micropores. On the premise of trying to avoid reducing the energy density, the performance of the battery is improved.

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

[0041] In a first aspect, referring to Figures 1-5 The battery electrode sheet provided by the embodiments of the present application comprises a current collector 100 and an active material layer 200 coated on at least one surface of the current collector 100.

[0042] The at least middle region of the at least one active material layer 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.

[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 output to the outside, which can be a rectangular sheet structure, and in lithium ion batteries, it is mainly a metal foil, such as a copper foil or an aluminum foil. For example, the current collector 100 in the positive electrode plate is usually an aluminum foil, and the current collector 100 in the negative electrode plate is usually a copper foil. Of course, the current collector 100 can also include a tab on one side.

[0044] The active material layer 200 can be coated on one surface of the current collector 100, or can be coated on both surfaces. For the positive electrode plate, the active material layer 200 thereon can include at least one of lithium-containing olivine phosphate, lithium transition metal oxide, and their respective modified compounds. Among them, the lithium-containing olivine phosphate can include, but is not limited to, at least one of lithium iron phosphate (such as LiFePO4, abbreviated 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 manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. 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 can include at least one of artificial graphite, natural graphite, mesocarbon microbeads, hard carbon, soft carbon, silicon, silicon-oxygen, silicon-carbon, and silicon alloy. Moreover, the electrolyte used in the battery can include an electrolyte salt and a solvent, the electrolyte salt includes at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoroboric oxalate, lithium difluoroboric oxalate, lithium difluorophosphoric oxalate, and lithium tetrafluorophosphoric oxalate. The electrolyte of the electrolyte is not limited to any one of the above.

[0046] Specifically, as shown in FIG. 1A, the at least middle region of the at least one active material layer 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 can be circular holes, conical holes, special-shaped holes, etc., the first micropores 210 and the second micropores 220 can be arranged in an array, staggered, etc. in the active material layer 200, and the first micropores 210 and the second micropores 220 can or can not penetrate the current collector 100. Of course, the first micropores 210 and the second micropores 220 can also be filled in the entire active material layer 200, which can be determined according to actual needs. Figure 2 Figure 2 The at least middle region of the at least one active material layer 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 can be circular holes, conical holes, special-shaped holes, etc., the first micropores 210 and the second micropores 220 can be arranged in an array, staggered, etc. in the active material layer 200, and the first micropores 210 and the second micropores 220 can or can not penetrate the current collector 100. Of course, the first micropores 210 and the second micropores 220 can also be filled in the entire active material layer 200, which can be determined according to actual needs.​

[0047] In this way, when the electrolyte diffuses in the active material layer 200, it can diffuse along the radial direction of each first micropore 210 and each second micropore 220, respectively, so that the infiltration speed during electrolyte filling can be accelerated. 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 manner shortens the diffusion distance of lithium ions and reduces the diffusion impedance of lithium ions, which is beneficial to the fast charging of the battery. During the charging and discharging process of the battery, the active material swells, causing the volume of the electrode sheet to expand, which can easily produce defects such as active material peeling. The presence of micropores allows the swelling stress to be evenly released, reducing the defects caused by the expansion of the electrode sheet.

[0048] Moreover, the second micropores 220 have a smaller pore size than the first micropores 210. The electrolyte mainly accelerates the infiltration through the adjacent first micropores 210, and the second micropores 220 compensate for the infiltration speed in the area far from the first micropores 210, so that the infiltration speed is basically uniform everywhere, achieving better distribution of the solvent during the electrolyte diffusion and the charging and discharging process, uniform diffusion, and 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 micropores 220 to be smaller than that of the first micropores 210, the material loss of the active material layer 200 can be minimized, and the performance of the battery can be improved without reducing the energy density.

[0050] Therefore, the battery electrode sheet provided in the embodiments of the present application 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 charging and discharging, a plurality of first micropores 210 and a plurality of second micropores 220 are arranged in at least the middle region of the 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 when infiltrating, 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 that of the first micropores 210, so that the performance of the battery can be improved without reducing the energy density.

[0051] In one possible design, each first micropore 210 and each second micropore 220 is arranged in a rectangular array, and the second micropores 220 and the first micropores 210 are arranged alternately.

[0052] Specifically, as shown in FIG. 1, the first micropores 210 and the second micropores 220 are arranged in a rectangular array, and the second micropores 220 and the first micropores 210 are arranged alternately. Figure 2As shown, each first micropore 210 and each second micropore 220 is distributed along the length and width direction of the current collector 100, thereby forming a rectangular array. Moreover, each second micropore 220 and each first micropore 210 are staggered with each other. For example, every four first micropores 210 can form a minimum rectangle, and the center of the minimum rectangle corresponds to one second micropore 220. In this way, the infiltration, diffusion, etc. of the electrolyte is more uniform, and the micropore processing is facilitated, etc.

[0053] Further, in the embodiment, the distance between two adjacent first micropores 210 is 30 μm-2000 μm, and the distance between the second micropore 220 and the adjacent first micropore 210 is 15 μm-1000 μm.

[0054] Specifically, as shown in Figure 2 , Figure 3 , the distance a1, a2 between two adjacent first micropores 210 is 30 μm-2000 μm, and the distance b1, b2 between the second micropore 220 and the adjacent first micropore 210 is 15 μm-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 the embodiment.

[0055] Further, in the embodiment, each first micropore 210 encloses a micropore region A, and 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, as shown in Figure 2 , 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 as to cover the active material layer 200 with the micropores as much as possible. The specific values of l1, l2, L1, and L2 can be determined according to actual processing requirements, and are not specifically limited in the embodiment.

[0057] Further, in the embodiment, the side of the active material layer 200 and the adjacent first micropore 210 or second micropore 220 has a spacing, and the spacing is greater than or equal to 10 μm.

[0058] Specifically, as shown in Figure 3 , the side of the active material layer 200 and the center of the adjacent first micropore 210 has a spacing c1, c2, and c1, c2 is greater than or equal to 10 μm, so as 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 the embodiment.

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

[0060] Specifically, such as Figure 3 As shown, the pore size of the first micropore 210 The size ranges from 1μm to 200μm, with the second micropore being 220. The micrometer size ranges from 1 μm to 200 μm. Among them, those satisfying the second micropore size of 220... Aperture smaller than the first micropore 210 That's all, for The specific values ​​can be determined according to actual processing requirements, and are not specifically limited in this embodiment.

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

[0062] Specifically, such as 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 the actual processing requirements, and is not specifically limited in this embodiment.

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

[0064] Specifically, continue as Figure 4 As shown, the first microvia 210 or the second microvia 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 microvia is related to the processing method, which includes, but is not limited to, laser etching for hole formation, mechanical mold processing for hole formation, and etching with a hole-forming agent for hole formation.

[0065] In some embodiments, the two opposing surfaces of the current collector 100 are coated with an active material layer 200, and each of the two active material layers 200 is provided with a plurality of first micropores 210 and a plurality of second micropores 220.

[0066] This setting, such as Figure 5 As shown, this allows for a faster wetting rate in both the upper and lower active material layers 200, ensuring product consistency.

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

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

[0069] In a second aspect, the embodiments of the present application further provide a battery, comprising a shell and an electric core 10 arranged in the shell, the electric core comprising a plurality of battery pole pieces provided by any of the above embodiments.

[0070] Specifically, as shown, Figure 6 The electric core 10 is stacked or wound by a plurality of battery pole pieces, including positive pole pieces and negative pole pieces, and it should be noted that a separator is arranged between adjacent pole pieces. The number of battery pole pieces can be determined according to actual needs, and is not specifically limited in the embodiments.

[0071] The shell is used to package the electric core 10, and the shape thereof can be a cuboid, a cylinder, etc., and the inside thereof has a receiving cavity for receiving the electric core and other components. For a cuboid shell, the battery pole pieces inside are stacked with each other. For a cylindrical shell, the battery pole pieces inside are wound.

[0072] Of course, other necessary components, such as explosion-proof valves and pole columns, are arranged on the inside or outside of the shell of the above battery, and the specific necessary components, shape, size, etc. of the battery can be determined according to actual needs, and are not excessively limited in the embodiments.

[0073] The battery provided by the embodiments of the present application is configured by a battery pole piece, the battery pole piece comprises 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 charging and discharging, a plurality of first micropores 210 and a plurality of second micropores 220 are arranged on at least the middle region of the at least one active material layer 200, so that the electrolyte can quickly diffuse into the active material layer 200 through the first micropores 210 and the second micropores 220 when it is soaked, and 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 that of the first micropores 210, so that the performance of the battery is improved while the energy density is reduced as much as possible.

[0074] In a third aspect, the embodiments of the present application further provide a battery pack, comprising a plurality of batteries provided by any of the above embodiments.

[0075] The battery pack provided by the embodiments of the present application is configured by a battery, the battery includes a plurality of battery pole pieces, 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 charging and discharging, a plurality of first micropores 210 and a plurality of second micropores 220 are arranged in at least a middle region of the 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 when the electrolyte is infiltrated, and 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, so that the performance of the battery is improved without reducing the energy density as much as possible.

[0076] In a fourth aspect, the embodiments of the present application also provide a power utilization device, which includes a device body, and the device body is provided with the battery or the battery pack provided by any of the above embodiments.

[0077] The vehicle provided by the embodiments of the present application is configured by the above battery or battery pack, the battery includes a plurality of battery pole pieces, 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 charging and discharging, a plurality of first micropores 210 and a plurality of second micropores 220 are arranged in at least a middle region of the 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 when the electrolyte is infiltrated, and 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, so that the performance of the battery is improved without reducing the energy density as much as possible.

[0078] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0079] It should be understood that the application is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application is limited only by the appended claims.

Claims

1. A battery electrode, characterized in that, It includes a current collector (100) and an active material layer (200) coated on at least one surface of the current collector (100). At least one of the active material layers (200) has at least a plurality of first micropores (210) and a plurality of second micropores (220) in its central region. The first micropores (210) and the second micropores (220) are spaced apart from each other and staggered. The pore size of the second micropores (220) is smaller than that of the first micropores (210). 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). The side of the active material layer (200) has a gap between it and the adjacent first micropore (210) or second micropore (220), the gap being greater than or equal to 10 μm.

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 electrode according to claim 2, characterized in that, The distance between two adjacent first micropores (210) is 30μm~2000μm, and the distance between the second micropore (220) and the adjacent first micropore (210) is 15μm~1000μm.

4. The battery electrode according to any one of claims 1 to 3, characterized in that, The pore size of the first micropore (210) and / or the second micropore (220) is 1μm~200μm.

5. The battery electrode according to claim 4, characterized in that, The depth of the first micropore (210) and / or the second micropore (220) is 5 μm to 200 μm.

6. The battery electrode according to claim 4, characterized in that, The opening of the first micropore (210) and / or the second micropore (220) is greater than or equal to the bottom of the pore.

7. The battery electrode according to claim 4, characterized in that, The current collector (100) has two opposing surfaces coated with the active material layer (200), and each of the two active material layers (200) is provided with a plurality of first micropores (210) and a plurality of second micropores (220).

8. The battery electrode according to claim 7, characterized in that, The first micropore (210) and the second micropore (220) on the two active material layers (200) pass through the current collector (100) and are correspondingly connected.

9. A battery, characterized in that, It includes a housing and a battery cell (10) disposed within the housing, the battery cell (10) including a plurality of battery electrodes as described in any one of claims 1 to 8.

10. A battery pack, characterized in that, It includes multiple batteries as described in claim 9.

11. An electrical appliance, characterized in that, Includes a device body, on which a battery as described in claim 9 is disposed; Alternatively, the device body may be provided with a battery pack as described in claim 10.

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