Electrode assembly, battery and electrical device

Abstract

The electrode assembly, battery, and electrical device include a first pole piece, a separator film, and a second pole piece arranged in this order. The electrode assembly further includes a pole tab, a first insulating layer, and a second insulating layer. The first pole piece includes a first current collector and a first active material layer applied in a first direction to both sides of the first current collector. The first active material layer has a pole tab groove, and the pole tab groove is provided with a pole tab. At least one surface of the first active material layer has a thinned region communicating with the pole tab groove. The thinned region includes a first recess spaced from the pole tab groove in the first direction and a second recess between the first recess and the pole tab groove. The first insulating layer is provided in the second recess. The second insulating layer is connected to the side of the second pole piece facing the first recess, and the projection of the second insulating layer in the first direction is located in the first recess. The electrode assembly can improve the energy density at a point and reduce the risk of lithium precipitation.

Description

[Technical Field]

[0001] The present application relates to the field of energy storage technology, and in particular to electrode assemblies, batteries and electrical devices. [Background technology]

[0002] In conventional battery structures, both the electrode tabs and electrode pieces have protruding glue paper. When the glue paper overlaps after winding, it affects the flatness of the battery. At the location where the electrode piece glue paper and the active material are transferred, lithium deposition is likely to occur during the charge / discharge process, affecting battery cycling. At the same time, the protruding glue paper affects the battery's energy density. Summary of the Invention

[0003] In view of the above circumstances, it is necessary to provide an electrode assembly that can solve the above problems.

[0004] One aspect of the present application provides an electrode assembly including a first pole piece, a separator film, and a second pole piece arranged in this order. The electrode assembly further includes a pole tab, a first insulating layer, and a second insulating layer. The first pole piece includes a first current collector and a first active material layer applied to both sides of the first current collector in a first direction, the first direction being the thickness direction of the first current collector. The first active material layer has a pole tab groove that exposes the first current collector, and the pole tab groove has a pole tab connected to the first current collector. At least one surface of the first active material layer has a thinned region that communicates with the pole tab groove, and the thinned region includes a first recess spaced from the pole tab groove in the first direction and a second recess between the first recess and the pole tab groove. The second direction is defined as the width direction of the first current collector. When viewed along the second direction, the bottom wall of the second recess is partitioned by the pole lug groove to form two spaced-apart first step surfaces, and the bottom wall of the first recess is partitioned by the second recess to form two spaced-apart second step surfaces. A first insulating layer is provided in the second recess, and both ends of the first insulating layer are located on the two first step surfaces. A second insulating layer is connected to the side of the second pole piece facing the first recess, and a projection of the second insulating layer in the first direction is located in the first recess. Along the first direction, the relationships among the depth T1 of the first recess, the depth T2 of the second recess, the thickness L1 of the first insulating layer, and the thickness L2 of the second insulating layer satisfy the following relationships: T1≦L2, T2≧L1, T1≦5 μm, and 5 μm≦L2≦20 μm.

[0005] In the electrode assembly, the second recess accommodates the first insulating layer, and the first recess accommodates at least a portion of the second insulating layer, thereby improving the flatness of the electrode assembly and thereby improving the energy density of a battery equipped with the electrode assembly. The difference in thickness between the first active material layers located at both ends of the second insulating layer and the corresponding active material layers on the second electrode piece is limited to a depth T1 of the first recess of 5 μm or less, thereby reducing the risk of lithium precipitation.

[0006] In some embodiments of the present application, by satisfying the condition 1 μm≦T1≦3 μm, the difference in thickness between the first active material layers located at both ends of the second insulating layer and the corresponding active material layers on the second pole piece can be further limited, thereby reducing the risk of lithium deposition.

[0007] One aspect of the present application provides an electrode assembly including a first pole piece, a separator film, and a second pole piece arranged in this order. The electrode assembly further includes a pole tab, a first insulating layer, and a second insulating layer. The first pole piece includes a first current collector and a first active material layer applied to both sides of the first current collector in a first direction, the first direction being the thickness direction of the first current collector. The first active material layer has a pole tab groove that exposes the first current collector, and the pole tab groove has a pole tab connected to the first current collector. At least one surface of the first active material layer has a thinned region that communicates with the pole tab groove, and the thinned region includes a first recess spaced from the pole tab groove in the first direction and a second recess between the first recess and the pole tab groove. The second direction is defined as the width direction of the first current collector. When viewed along the second direction, the bottom wall of the second recess is separated by the pole lug groove to form two first step surfaces spaced apart, and the bottom wall of the first recess is separated by the second recess to form two second step surfaces spaced apart. A first insulating layer is provided in the second recess, and both ends of the first insulating layer are located on the two first step surfaces. The second insulating layer is connected to the side of the second pole piece facing the first recess, and a projection of the second insulating layer in the first direction is located in the first recess. When viewed along the second direction, the first active material layer further includes flat-coated regions located on both sides of the shaved region, and the electrode assembly further includes two third insulating layers connected to both ends of the second insulating layer, and a projection of each of the third insulating layers in the first direction extends from the first recess to the flat-coated region.

[0008] In the above electrode assembly, the second recess accommodates the first insulating layer, and the first recess accommodates at least a portion of the second insulating layer, thereby improving the flatness of the electrode assembly and thereby improving the energy density of a battery equipped with the electrode assembly. The third insulating layer increases the cathode impedance, thereby reducing the risk of lithium deposition due to a large difference in thickness between the first active material layers on both ends of the second insulating layer and the corresponding active material layers on the second electrode piece.

[0009] In some embodiments of the present application, the relationships among the depth T1 of the first recess, the depth T2 of the second recess, the thickness L1 of the first insulating layer, and the thickness L2 of the second insulating layer along the first direction satisfy T1≧L2, T2≧L1, and T1>5m, so that the second insulating layer is completely fitted into the first recess and the first insulating layer is completely accommodated in the second recess, thereby reducing the impact of the second insulating layer and the first insulating layer on the flatness of the electrode assembly.

[0010] In some embodiments of the present application, the third insulating layer is formed by coating polyvinyl alcohol, polyacrylic acid, or a mixture of both onto the second pole piece.

[0011] In some embodiments of the present application, the thickness L3 of the third insulating layer along the first direction satisfies 2 μm≦L3≦5 μm, thereby reducing the impact of the third insulating layer on the flatness of the electrode assembly while maintaining stable insulating performance.

[0012] In some embodiments of the present application, the third direction is defined as the longitudinal direction of the first current collector, and along the third direction, the length D3 of the third insulating layer satisfies 4 mm≦D3≦8 mm, and the projection of the third insulating layer in the first direction extends from the first recess to the flat-coated area.

[0013] In some embodiments of the present application, the relationship between the length W1 of the first recess, the length W2 of the second recess, the length D1 of the first insulating layer, and the length D2 of the second insulating layer along the third direction satisfies W1≧D2, W2≧D1, W1>W2, and D2>D1, such that the second recess accommodates the first insulating layer in the third direction and the first recess accommodates the second insulating layer in the third direction.

[0014] In some embodiments of the present application, the first active material layer includes a first surface and a second surface facing each other in a first direction. The shaving region includes a first shaving region provided on the first surface and a second shaving region provided on the second surface. Along the first direction, a projection of the first recess in the first shaving region overlaps with a projection of the first recess in the second shaving region, and a projection of the second recess in the first shaving region overlaps with a projection of the second recess in the second shaving region. The first shaving region and the second shaving region cooperate to reduce the effect of the first insulating layer and the second insulating layer on the flatness of the electrode assembly and reduce the risk of lithium precipitation.

[0015] In some embodiments of the present application, the first current collector located in the pole lug groove is provided with a third recess recessed along the first direction, and the pole lug is accommodated in the third recess. The third recess is intended to reduce the effect of the pole piece on the thickness of the first pole piece 10 in the first direction.

[0016] In some embodiments of the present application, the first active material layer includes a first surface and a second surface facing each other in a first direction. The first active material layer includes a thinning region, the thinning region being provided on one of the first surface and the second surface. The electrode assembly includes a fourth insulating layer connected to the other of the first surface and the second surface and covering one end of the pole lug groove away from the thinning region, and a fifth insulating layer connected to the side of the second pole piece facing the fourth insulating layer. Along the first direction, a projection of the first insulating layer overlaps with a projection of the fourth insulating layer, and a projection of the second insulating layer overlaps with a projection of the fifth insulating layer.

[0017] In some embodiments of the present application, the relationships among the depth T1 of the first recess, the depth T2 of the second recess, the thickness L1 of the first insulating layer, the thickness L2 of the second insulating layer, the thickness L4 of the fourth insulating layer, and the thickness L5 of the fifth insulating layer along the first direction satisfy L1 + L4 ≦ T2 and L2 + L5 ≦ T1. The first recess eliminates the influence of the second insulating layer and the fifth insulating layer on the flatness of the electrode assembly, and the second recess eliminates the influence of the first insulating layer and the fourth insulating layer on the flatness of the electrode assembly, and can further reduce the risk of lithium precipitation.

[0018] The present invention provides a battery having the electrode assembly according to any of the above embodiments.

[0019] An embodiment of the present invention provides an electrical device having the battery of any of the above embodiments.

[0020] In the battery and electrical device of the present application, the second recess accommodates the first insulating layer, and the first recess accommodates at least a portion of the second insulating layer, thereby improving the flatness of the electrode assembly and ultimately improving the energy density of the battery provided with the electrode assembly. In a first aspect, the difference in thickness between the first active material layer located at both ends of the second insulating layer and the active material layer on the corresponding second electrode piece is limited to a depth T1 of the first recess of 5 μm or less, thereby reducing the risk of lithium deposition. In a second aspect, the third insulating layer increases the cathode impedance, thereby reducing the risk of lithium deposition due to a large difference in thickness between the first active material layer located at both ends of the second insulating layer and the active material layer on the corresponding second electrode piece. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram of a first configuration of an electrode assembly in one embodiment of the present application. [Figure 2] FIG. 2 is a schematic diagram showing the dimensions of an electrode assembly in one embodiment of the present application. [Figure 3] FIG. 3 is a schematic diagram of a second configuration of an electrode assembly in one embodiment of the present application. [Figure 4] FIG. 4 is a comparison diagram of cycle thickness expansion data for a battery in one embodiment of the present application. [Figure 5] FIG. 5 is a schematic diagram of a third configuration of an electrode assembly in one embodiment of the present application. [Figure 6] FIG. 6 is a diagram showing the configuration of a battery and an electrical device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, technical aspects of the embodiments of the present application will be described in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application and are not limited to all the embodiments.

[0023] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to the other element, or there may be a centrally located component present. When an element is considered to be "mounted" to another element, it may be directly mounted to the other element, or there may be a centrally located component present.

[0024] Unless otherwise defined, technical and scientific terms used in the specification of this application have the same meaning as commonly understood by those skilled in the art of this application. The terms used in the specification of this application are only for describing particular embodiments and are not intended to limit the application. The term "and / or" used in the specification of this application includes any and all combinations of one or more associated listed items.

[0025] In addition, taking into consideration the actual processing tolerance factors, in the technical solution of the present application, when two elements are installed parallel / perpendicularly, they are installed in the same direction, and there can be a certain angle between the two elements, and a tolerance of 0 to ±10% is allowed between the two elements, and the two elements can be greater than, equal to, or smaller than the allowed tolerance of 0 to ±10%.

[0026] The embodiments of the present application will be further explained with reference to the drawings.

[0027] 1, an embodiment of the present application provides an electrode assembly 100 including a first pole piece 10, a separator film 20, and a second pole piece 30 arranged in that order. Alternatively, the first pole piece 10, the separator film 20, and the second pole piece 30 are arranged to be wound or stacked.

[0028] The electrode assembly 100 further includes a pole tab 40, a first insulating layer 51, and a second insulating layer 52. The first pole piece 10 includes a first current collector 11 and a first active material layer 12 applied to both sides of the first current collector 11 in a first direction Z, which is the thickness direction of the first current collector 11. The first active material layer 12 is provided with a pole tab groove 13 exposing the first current collector 11, and the pole tab groove 13 is provided with a pole tab 40 connected to the first current collector 11. The first active material layer 12 can enable the desorption and implantation of lithium ions. The first current collector 11 conducts current generated by an electrochemical reaction to an external circuit via the pole tab 40, thereby converting chemical energy into electrical energy.

[0029] The second direction X is defined as the width direction of the first current collector 11, and the third direction Y is defined as the longitudinal direction of the first current collector 11. The longitudinal direction and width direction of the first current collector 11 each refer to two dimensions on the surface of the first current collector 11. Here, the longitudinal direction refers to the main dimension (i.e., the direction in which the dimension is larger), and the width direction refers to the second dimension (i.e., the direction in which the dimension is smaller). Typically, the longitudinal direction coincides with the coating direction of each material layer (e.g., the first active material layer 12) in the processing step of the first pole piece 10, and also coincides with the winding direction of the first pole piece 10, separator film 20, and second pole piece 30. The width direction is perpendicular to the longitudinal direction.

[0030] At least one surface of the first active material layer 12 is provided with a thinning region 12a that communicates with the pole lug groove 13, and the thinning region 12a has a first recess 121 that is spaced apart from the pole lug groove 13 in the first direction Z, and a second recess 122 that is provided between the first recess 121 and the pole lug groove 13. When viewed along the second direction X, the bottom wall of the second recess 122 is separated by the pole lug groove 13 and forms two first step surfaces 122a that are spaced apart, and the bottom wall of the first recess 121 is separated by the second recess 122 and forms two second step surfaces 121a that are spaced apart.

[0031] The first insulating layer 51 is provided in the second recess 122, and both ends of the first insulating layer 51 are located on the two first step surfaces 122a, respectively, and the first insulating layer 51 separates the pole tab 40 and the second pole piece 30.

[0032] The second insulating layer 52 is connected to one side of the second pole piece 30 facing the first recess 121, and the projection of the second insulating layer 52 in the first direction Z is located in the first recess 121, further separating the pole tab 40 from the second pole piece 30. Specifically, the separator film 20 includes a first portion 21 adjacent to the second insulating layer 52, and the projection of the second insulating layer 52 and the projection of the first portion 21 overlap along the first direction Z. In the first direction Z, at least a portion of the second insulating layer 52 is fitted into the first recess 121, and the first portion 21 is fitted into the first recess 121 by driving the second insulating layer 52, and both ends of the projection of the second insulating layer 52 in the first direction Z are respectively located on the two second step surfaces 121a.

[0033] By accommodating the first insulating layer 51 in the second recess 122, the first recess 121 accommodates at least a portion of the second insulating layer 52, improving the flatness of the electrode assembly 100 and ultimately improving the energy density of the battery in which the electrode assembly 100 is provided.

[0034] Referring also to Figure 2, along the third direction Y, the relationship between the length W1 of the first recess, the length W2 of the second recess, the length D1 of the first insulating layer, and the length D2 of the second insulating layer satisfies W1≧D2, W2≧D1, W1>W2, and D2>D1, making it easy for the second recess 122 to accommodate the first insulating layer 51 in the third direction Y and for the first recess 121 to accommodate the second insulating layer 52 in the third direction Y.

[0035] Referring to FIGS. 1 and 2 together, in some embodiments, along the first direction Z, the relationship between the depth T1 of the first recess 121, the depth T2 of the second recess 122, the thickness L1 of the first insulating layer 51, and the thickness L2 of the second insulating layer 52 satisfies T1≤L2, T2≥L1, T1≤5 μm, and 5 μm≤L2≤20 μm. Specifically, in the second direction Z, at least a part of the second insulating layer 52 is embedded in the first recess 121 so as to eliminate the influence of the second insulating layer 52 on the flatness of the electrode assembly 100. Alternatively, when T1 = L2, the second insulating layer 52 is completely embedded in the first recess 121, and when T1 < L2, a part of the second insulating layer 52 is embedded in the first recess 121. The first insulating layer 51 is completely fitted into the second recess 122 so as to eliminate the influence of the first insulating layer 51 on the flatness of the electrode assembly 100. By setting T1≤5 μm, the difference in thickness between the first active material layer 12 located at both ends of the second insulating layer 52 and the active material layer on the corresponding second electrode tab 30 is restricted, reducing the risk of lithium precipitation.

[0036] Note that the second electrode tab 30 includes a second current collector 31 and second active material layers 32 coated on both sides of the second current collector 31. Along the first direction Z, it is understood that the thickness of the second active material layer 32 is the same as the thickness of the portion where the thinning region 12a of the first active material layer 12 is not provided.

[0037] Alternatively, T1 may be one of 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, or any other numerical value within the range of T1≤5 μm.

[0038] Furthermore, by setting 1 μm≤T1≤3 μm, the difference in thickness between the first active material layer 12 located at both ends of the second insulating layer 52 and the active material layer on the corresponding second electrode tab 30 is further restricted, reducing the risk of lithium precipitation.

[0039] Furthermore, by setting T1 to 1 μm, the difference in thickness between the first active material layer 12 located at both ends of the second insulating layer 52 and the active material layer on the corresponding second electrode tab 30 is further restricted, reducing the risk of lithium precipitation.

[0040] Alternatively, L2 may be one of 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, and any other value in the range 5 μm≦L2≦20 μm.

[0041] 3 , in some embodiments, the relationships among the depth T1 of the first recess 121, the depth T2 of the second recess 122, the thickness L1 of the first insulating layer 51, and the thickness L2 of the second insulating layer 52 along the first direction Z satisfy T1≧L2, T2≧L1, and T1>5 μm. Specifically, the second insulating layer 52 is completely fitted into the first recess 121 so as to eliminate the effect of the second insulating layer 52 on the flatness of the electrode assembly 100 in the second direction Z. The first insulating layer 51 is completely accommodated in the second recess 122 so as to eliminate the effect of the first insulating layer 51 on the flatness of the electrode assembly 100.

[0042] The first active material layer 12 further includes flat-coated regions 12b located on both sides of the thinned region 12a when viewed along the second direction X. The electrode assembly 100 further includes two third insulating layers 53 connected to both ends of the second insulating layer 52. The projection of each third insulating layer 53 in the first direction Z extends from the first recess 121 to the flat-coated region 12b. Specifically, each third insulating layer 53 extends from the end of the second insulating layer 52 to the outside of the first recess 121. The third insulating layer 53 separates the first active material layers 12 located at both ends of the second insulating layer 52 from the corresponding active material layers on the second pole pieces 30. This reduces the risk of lithium deposition due to a large difference in thickness between the first active material layers 12 located at both ends of the second insulating layer 52 and the corresponding active material layers on the second pole pieces 30.

[0043] It is understood that when T1≦5 μm, by providing two third insulating layers 53 on both ends of the second insulating layer 52, the risk of lithium deposition can be further reduced.

[0044] Referring to FIG. 4, the third insulating layer 53 can be formed by applying polyvinyl alcohol (PVA), polyacrylic acid (PAA), or a mixture of the two to the second pole piece 30, which can increase the cathode impedance at the applied position after application, reduce the amount of lithium ion escape at the corresponding position, and reduce the risk of lithium deposition at the applied position.

[0045] In some embodiments, the thickness L3 of the third insulating layer 53 along the first direction Z satisfies 2 μm≦L3≦5 μm, thereby reducing the impact of the third insulating layer 53 on the flatness of the electrode assembly 100 while maintaining insulating performance.

[0046] Alternatively, L3 may be one of 2 μm, 3 μm, 4 μm, 5 μm, and any other value in the range 2 μm≦L3≦5 μm.

[0047] In some embodiments, along the third direction Y, the length D3 of the third insulating layer 53 satisfies 4 mm≦D3≦8 mm to facilitate the projection of the third insulating layer 53 in the first direction Z extending from the first recess 121 to the flat coating area 12b.

[0048] Alternatively, L3 may be one of 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, or any other value in the range 4 mm≦D3≦8 mm.

[0049] In some embodiments, first active material layer 12 has first surface 123 and second surface 124 arranged opposite each other in first direction Z, with first surface 123 and second surface 124 located on opposite sides of first current collector 11. Scraping region 12a includes first scraping region 12c provided on first surface 123 and second scraping region 12d provided on second surface 124.

[0050] The first and second shaving regions 12c and 12d are provided with a first recess 121 and a second recess 122, respectively. Along the first direction Z, the projection of the first recess 121 in the first shaving region 12c overlaps with the projection of the first recess 121 in the second shaving region 12d, and the projection of the second recess 122 in the first shaving region 12c overlaps with the projection of the second recess 122 in the second shaving region 12d. Correspondingly, the first and second shaving regions 12c and 12d are provided with a first insulating layer 51 and a second insulating layer 52, respectively. The first and second shaving regions 12c and 12d are blended to reduce the impact of the first and second insulating layers 51 and 52 on the flatness of the electrode assembly 100 and further reduce the risk of lithium precipitation.

[0051] It is understood that the third insulating layer 53 can be selectively provided in the first thinning region 12c and the second thinning region 12d depending on the depth T1 of the respective first recesses 121. Specifically, when the depth T1 of the first recesses 121 in both the first thinning region 12c and the second thinning region 12d is ≦ 5 μm, the third insulating layer 53 is not provided in either the first thinning region 12c or the second thinning region 12d. When the depth T1 of the first recesses 121 in both the first thinning region 12c and the second thinning region 12d is > 5 μm, the first thinning region 12c and the second thinning region 12d are each provided with a third insulating layer 53, and the projections of the two third insulating layers 53 located on the pole ear 40 side in the third direction Y in the first direction Z overlap. When the depth T1 of the first recess 121 in the first shaving region 12c is ≦ 5 μm and the depth T1 of the first recess 121 in the second shaving region 12d is > 5 μm, the first shaving region 12c is not provided with the third insulating layer 53 and the second shaving region 12d is provided with the third insulating layer 53. When the depth T1 of the first recess 121 in the first shaving region 12c is > 5 μm and the depth T1 of the first recess 121 in the second shaving region 12d is ≦ 5 μm, the first shaving region 12c is provided with the third insulating layer 53 and the second shaving region 12d is not provided with the third insulating layer 53.

[0052] 5, in some embodiments, the first active material layer 12 is provided with one shaving region 12a, and the shaving region 12a is provided on either the first surface 123 or the second surface 124. The electrode assembly 100 further includes a fourth insulating layer 54 connected to the other of the first surface 123 and the second surface 124 and covering one end of the pole lug groove 13 away from the shaving region 12a, and a fifth insulating layer 55 connected to the side of the second pole piece 30 facing the fourth insulating layer 54. The fourth insulating layer 54 and the fifth insulating layer 55 are intended to separate the pole lug 40 and the second pole piece 30 on the side away from the shaving region 12a.

[0053] Along the first direction Z, the projection of the first insulating layer 51 overlaps the projection of the fourth insulating layer 54, and the projection of the second insulating layer 52 overlaps the projection of the fifth insulating layer 55 so that the insulating area on both sides of the pole ear 40 is approximately the same and the stability of the insulation is improved.

[0054] Along the first direction Z, the relationship between the depth T1 of the first recess 121, the depth T2 of the second recess 122, the thickness L1 of the first insulating layer 51, the thickness L2 of the second insulating layer 52, the thickness L4 of the fourth insulating layer 54, and the thickness L5 of the fifth insulating layer 55 is L1+L4≦T2, L2+L5≦T1. Specifically, in the first direction Z, the second insulating layer 52 is completely fitted into the first recess 121, and the first insulating layer 51 is completely fitted into the second recess 122. The first recess 121 can eliminate the influence of the second insulating layer 52 and the fifth insulating layer 55 on the flatness of the electrode assembly 100, and the second recess 122 can eliminate the influence of the first insulating layer 51 and the fourth insulating layer 54 on the flatness of the electrode assembly 100, further reducing the risk of lithium precipitation.

[0055] In some embodiments, the first current collector 11 located in the electrode ear groove 13 has a third recess 111 recessed along the first direction Z, and the third recess 111 is intended to reduce the effect of the electrode ear 40 on the thickness of the first electrode sheet 10 in the first direction Z.

[0056] Referring to FIG. 6, an embodiment of the present application provides a battery 200 including the electrode assembly 100 of any of the above-described embodiments.

[0057] Referring to FIG. 6, an embodiment of the present application provides an electric device 300 including the battery 200 of any of the above-described embodiments, and the electric device 300 may be an electronic device such as a mobile phone, a polaroid, or a mobile device such as a drone, an electric vehicle, or the like.

[0058] As a result, in the electrode assembly 100, battery 200, and electrical device 300, the second recess 122 accommodates the first insulating layer 51, and the first recess 121 accommodates at least a portion of the second insulating layer 52, improving the flatness of the electrode assembly 100 and ultimately improving the energy density of the battery in which the electrode assembly 100 is provided. First, the depth T1 of the first recess 121, which is 5 μm or less, limits the difference in thickness between the first active material layer 12 located at both ends of the second insulating layer 52 and the corresponding active material layer on the second pole piece 30, thereby reducing the risk of lithium deposition. Second, the third insulating layer 53 increases the cathode impedance, thereby reducing the risk of lithium deposition due to a large difference in thickness between the first active material layer 12 at both ends of the second insulating layer 52 and the corresponding active material layer on the second pole piece 30.

[0059] Examples 1 to 3 of the present application will be described in more detail below with reference to the drawings.

[0060] Example 1 Referring to FIG. 1, in the electrode assembly 100a according to Example 1 of the present application, the shaved region 12a includes a first shaved region 12c provided on the first surface 123 and a second shaved region 12d provided on the second surface 124. The first shaved region 12c and the second shaved region 12d are provided with a first recess 121 and a second recess 122, respectively. Along the first direction Z, a projection of the first recess 121 on the first shaved region 12c overlaps with a projection of the first recess 121 on the second shaved region 12d, and a projection of the second recess 122 on the first shaved region 12c overlaps with a projection of the second recess 122 on the second shaved region 12d. Correspondingly, a first insulating layer 51 and a second insulating layer 52 are provided in the first shaved region 12c and the second shaved region 12d, respectively. The depth T1 of the first recess 121 in both the first thinning region 12c and the second thinning region 12d is 5 μm or less, and the third insulating layer 53 is not provided in either the first thinning region 12c or the second thinning region 12d. Along the third direction Y, the length of the pole lug groove 13 is 9 mm, and the width of the pole lug 40 is 6 mm.

[0061] In the first thinning region 12c, the length D1 of the first insulating layer 51 is 11 mm, the thickness L1 of the first insulating layer 51 is 16 μm, the length W2 of the second recess 122 is 13 mm, the depth T2 of the second recess 122 is 18 μm, the length D2 of the second insulating layer 52 is 20 mm, the thickness L2 of the second insulating layer 52 is 10 μm, the length W1 of the first recess 121 is 26 mm, and the depth T1 of the first recess 121 is 5 μm.

[0062] In the second thinning region 12d, the length D1 of the first insulating layer 51 is 11 mm, the thickness L1 of the first insulating layer 51 is 16 μm, the length W2 of the second recess 122 is 13 mm, the depth T2 of the second recess 122 is 18 μm, the length D2 of the second insulating layer 52 is 20 mm, the thickness L2 of the second insulating layer 52 is 10 μm, the length W1 of the first recess 121 is 26 mm, and the depth T1 of the first recess 121 is 5 μm.

[0063] In the electrode assembly 100a, the second insulating layer 52 is fitted into the first recess 121 from outside the first recess 121 in the first direction Z so as to eliminate the effect of a portion of the second insulating layer 52 on the flatness of the electrode assembly 100. The first insulating layer 51 is completely contained in the second recess 122 so as to eliminate the effect of the first insulating layer 51 on the flatness of the electrode assembly 100. By setting T1≦5 μm, the difference in thickness between the first active material layer 12 located at both ends of the second insulating layer 52 and the corresponding active material layer on the second pole piece 30 is limited, thereby reducing the risk of lithium deposition.

[0064] Example 2 Referring to FIG. 4, in the electrode assembly 100b according to Example 1 of the present application, the shaved region 12a includes a first shaved region 12c provided on the first surface 123 and a second shaved region 12d provided on the second surface 124. The first shaved region 12c and the second shaved region 12d are provided with a first recess 121 and a second recess 122, respectively. Along the first direction Z, the projection of the first recess 121 on the first shaved region 12c overlaps with the projection of the first recess 121 on the second shaved region 12d, and the projection of the second recess 122 on the first shaved region 12c overlaps with the projection of the second recess 122 on the second shaved region 12d. Correspondingly, the first shaved region 12c and the second shaved region 12d are provided with a first insulating layer 51 and a second insulating layer 52, respectively. The depth T1 of the first recess 121 in both the first thin-cut region 12c and the second thin-cut region 12d is greater than 5 μm, and the third insulating layer 53 is provided in both the first thin-cut region 12c and the second thin-cut region 12d.

[0065] Along the third direction Y, the length of the pole lug groove 13 is 9 mm and the width of the pole lug 40 is 6 mm.

[0066] In the first thinning region 12c, the length D1 of the first insulating layer 51 is 11 mm, the thickness L1 of the first insulating layer 51 is 16 μm, the length W2 of the second recess 122 is 13 mm, the depth T2 of the second recess 122 is 18 μm, the length D2 of the second insulating layer 52 is 20 mm, the thickness L2 of the second insulating layer 52 is 10 μm, the length W1 of the first recess 121 is 26 mm, and the depth T1 of the first recess 121 is 12 μm.

[0067] In the second thinning region 12d, the length D1 of the first insulating layer 51 is 11 mm, the thickness L1 of the first insulating layer 51 is 16 μm, the length W2 of the second recess 122 is 13 mm, the depth T2 of the second recess 122 is 18 μm, the length D2 of the second insulating layer 52 is 20 mm, the thickness L2 of the second insulating layer 52 is 10 μm, the length W1 of the first recess 121 is 26 mm, and the depth T1 of the first recess 121 is 12 μm.

[0068] The thickness L3 of the third insulating layer 53 satisfies 2 μm≦L3≦5 μm, and the length D3 of the third insulating layer 53 satisfies 4 mm≦D3≦8 mm.

[0069] In the electrode assembly 100b, the second insulating layer 52 is completely fitted into the first recess 121 so as to eliminate the effect of the second insulating layer 52 on the flatness of the electrode assembly 100 in the first direction Z. The first insulating layer 51 is completely accommodated in the second recess 122 so as to eliminate the effect of the first insulating layer 51 on the flatness of the electrode assembly 100. The increase in cathode impedance due to the third insulating layer 53 can reduce the risk of lithium deposition due to a large difference in thickness between the first active material layer 12 on both ends of the second insulating layer 52 and the corresponding active material layer on the second pole piece 30.

[0070] Example 3 5, in the electrode assembly 100c according to Example 1 of the present application, the first active material layer 12 has one shaved region 12a on the first surface 123. The first shaved region 12c has a first recess 121 and a second recess 122. Correspondingly, the first shaved region 12c and the second shaved region 12d are provided with a first insulating layer 51 and a second insulating layer 52, respectively. The electrode assembly 100 further includes a fourth insulating layer 54 connected to the second surface 124 and covering one end of the pole lug 13 remote from the shaved region 12a, and a fifth insulating layer 55 connected to the side of the second pole piece facing the fourth insulating layer 54.

[0071] Along the third direction Y, the length of the pole lug groove 13 is 9 mm and the width of the pole lug 40 is 6 mm.

[0072] In the thinning region 12a, the length D1 of the first insulating layer 51 is 11 mm, the thickness L1 of the first insulating layer 51 is 16 μm, the length W2 of the second recess 122 is 13 mm, the depth T2 of the second recess 122 is 36 μm, the length D2 of the second insulating layer 52 is 20 mm, the thickness L2 of the second insulating layer 52 is 10 μm, the length W1 of the first recess 121 is 26 mm, and the depth T1 of the first recess 121 is 24 μm.

[0073] Along the third direction Y, the length of the fourth insulating layer 54 is 11 mm and the length of the fifth insulating layer 55 is 20 mm, and along the first direction Z, the thickness L4 of the fourth insulating layer 54 is 16 mm and the thickness L5 of the fifth insulating layer 55 is 10 mm.

[0074] In the electrode assembly 100b, in the first direction Z, the second insulating layer 52 is completely fitted into the first recess 121, the first insulating layer 51 is completely accommodated in the second recess 122, the fourth insulating layer 54 and the fifth insulating layer 55 can be pushed toward the thinning region 12a, the first recess 121 can eliminate the influence of the second insulating layer 52 and the fifth insulating layer 55 on the flatness of the electrode assembly 100, and the second recess 122 can eliminate the influence of the first insulating layer 51 and the fourth insulating layer 54 on the flatness of the electrode assembly 100. The third insulating layer 53 increases the cathode impedance, thereby reducing the risk of lithium deposition due to a large difference in thickness between the first active material layer 12 at both ends of the second insulating layer 52 and the corresponding active material layer on the second pole piece 30.

[0075] It should be noted that a person skilled in the art may make other modifications within the spirit of the present application, and it goes without saying that these modifications based on the spirit of the present application will fall within the scope of the disclosure of the present application. [Explanation of symbols]

[0076] 100, 100a, 100b, 100c electrode assembly 200 batteries 300 Electrical Equipment 10 First pole piece 11 First current collector 111 Third recess 12 First active material layer 12a Thinning area 121 First recess 121a 2nd stage surface 122 Second recess 122a 1st stage surface 123 Page 1 124 Side 2 12b Flat area 12c 1st thinning area 12d 2nd thinning area 13 Polar sulcus 20 Separator membrane 21 Part 1 30 Second pole piece 31 Second current collector 32 Second active material layer 40 polar ears 51 First insulating layer 52 Second insulating layer 53 Third insulating layer 54 Fourth insulating layer 55 5th insulating layer Z 1st direction X 2nd direction Y Third direction

Claims

1. a first pole piece, a separator membrane, and a second pole piece, which are arranged in this order; The electrode further includes a terminal, a first insulating layer, and a second insulating layer, the first pole piece includes a first current collector and a first active material layer coated on both sides of the first current collector in a first direction, the first direction being a thickness direction of the first current collector; an electrode assembly, wherein the first active material layer is provided with an electrode lug groove exposing the first current collector, and the electrode lug groove is provided with an electrode lug connected to the first current collector, a thinning region communicating with the electrode lug groove is provided on at least one surface of the first active material layer, the thinning region including a first recess provided away from the electrode lug groove in the first direction and a second recess provided between the first recess and the electrode lug groove, the second direction being defined as the width direction of the first current collector; When viewed along the second direction, a bottom wall of the second recess is partitioned by the pole lug groove and forms two first step surfaces spaced apart, and a bottom wall of the first recess is partitioned by the second recess and forms two second step surfaces spaced apart, the first insulating layer is provided in the second recess, and both ends of the first insulating layer are located on the two first step surfaces, respectively; the second insulating layer is connected to a side of the second pole piece facing the first recess, and a projection of the second insulating layer in the first direction is located in the first recess; The electrode assembly according to claim 1, wherein the relationships among the depth T1 of the first recess, the depth T2 of the second recess, the thickness L1 of the first insulating layer, and the thickness L2 of the second insulating layer along the first direction satisfy T1≦L2, T2≧L1, T1≦5 μm, and 5 μm≦L2≦20 μm.

2. 2. The electrode assembly according to claim 1, wherein T1 satisfies the condition 1 μm≦T1≦3 μm.

3. a first pole piece, a separator membrane, and a second pole piece, which are arranged in this order; The electrode further includes a terminal, a first insulating layer, and a second insulating layer, the first pole piece includes a first current collector and a first active material layer coated on both sides of the first current collector in a first direction, the first direction being a thickness direction of the first current collector; an electrode assembly, wherein the first active material layer is provided with an electrode lug groove exposing the first current collector, and the electrode lug groove is provided with an electrode lug connected to the first current collector, a thinning region communicating with the electrode lug groove is provided on at least one surface of the first active material layer, the thinning region including a first recess provided away from the electrode lug groove in the first direction and a second recess provided between the first recess and the electrode lug groove, the second direction being defined as the width direction of the first current collector; When viewed along the second direction, a bottom wall of the second recess is partitioned by the pole lug groove and forms two first step surfaces spaced apart, and a bottom wall of the first recess is partitioned by the second recess and forms two second step surfaces spaced apart, the first insulating layer is provided in the second recess, and both ends of the first insulating layer are located on the two first step surfaces, respectively; the second insulating layer is connected to a side of the second pole piece facing the first recess, and a projection of the second insulating layer in the first direction is located in the first recess, along the first direction; When viewed along the second direction, the first active material layer further includes flat-coated regions provided on both sides of the thinning region, The electrode assembly is characterized in that it further includes two third insulating layers connected to both ends of the second insulating layer, and the projection of each of the third insulating layers in the first direction extends from the first recess to the flat coating area.

4. 4. The electrode assembly of claim 3, wherein a depth T1 of the first recess, a depth T2 of the second recess, a thickness L1 of the first insulating layer, and a thickness L2 of the second insulating layer along the first direction satisfy relationships of T1 ≥ L2, T2 ≥ L1, and T1 > 5 m.

5. 4. The electrode assembly of claim 3, wherein the third insulating layer is formed by coating the second pole piece with polyvinyl alcohol, polyacrylic acid, or a mixture of both.

6. The electrode assembly of claim 3, wherein the thickness L3 of the third insulating layer in the first direction satisfies 2 μm≦L3≦5 μm.

7. 4. The electrode assembly of claim 3, wherein a third direction is defined as a longitudinal direction of the first current collector, and a length D3 of the third insulating layer along the third direction satisfies 4 mm≦D3≦8 mm.

8. 4. The electrode assembly of claim 1, wherein a third direction is defined as a longitudinal direction of the first current collector, and a length W1 of the first recess, a length W2 of the second recess, a length D1 of the first insulating layer, and a length D2 of the second insulating layer along the third direction satisfy relationships W1 ≧ D2, W2 ≧ D1, W1 > W2, and D2 > D1.

9. the first active material layer includes a first surface and a second surface that are provided opposite to each other in the first direction, The thinning area includes a first thinning area provided on the first surface and a second thinning area provided on the second surface, An electrode assembly as described in claim 1 or 3, characterized in that along the first direction, the projection of the first recess in the first thinning region overlaps with the projection of the first recess in the second thinning region, and the projection of the second recess in the first thinning region overlaps with the projection of the second recess in the second thinning region.

10. The electrode assembly according to claim 1 or 3, characterized in that the first current collector located in the electrode lug groove has a third recess recessed along the first direction, and the electrode lug is accommodated in the third recess.

11. the first active material layer includes a first surface and a second surface that are provided opposite to each other in the first direction, The first active material layer is provided with one of the shaved regions, and the shaved region is provided on one of the first surface and the second surface; The electrode assembly includes a fourth insulating layer connected to the other of the first surface and the second surface and covering one end of the pole lug away from the thinning region, and a fifth insulating layer connected to the side of the second pole piece facing the fourth insulating layer, 4. The electrode assembly of claim 1, wherein a projection of the first insulating layer overlaps a projection of the fourth insulating layer, and a projection of the second insulating layer overlaps a projection of the fifth insulating layer along the first direction.

12. 12. The electrode assembly of claim 11, wherein a depth T1 of the first recess, a depth T2 of the second recess, a thickness L1 of the first insulating layer, a thickness L2 of the second insulating layer, a thickness L4 of the fourth insulating layer, and a thickness L5 of the fifth insulating layer in the first direction satisfy relationships L1 + L4 ≦ T2 and L2 + L5 ≦ T1.

13. A battery comprising the electrode assembly according to any one of claims 1 to 12.

14. An electrical device further comprising the battery of claim 13.

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