Pole piece, battery cell and current collector assembly

Abstract

The utility model discloses a pole piece, a battery cell and a current collector assembly. The pole piece comprises a first substrate, a first active material layer and a first insulating layer. The first substrate is provided with a first wall surface and a first active material layer, the first wall surface is coated with the first active material layer, the first active material layer comprises a core part and an edge part arranged around the core part, the first substrate or the first active material layer is coated with the first insulating layer, and the first insulating layer covers at least part of the edge part in the thickness direction perpendicular to the first wall surface. According to the technical scheme, the first substrate or the first active material layer is coated with the first insulating layer, and the first insulating layer covers at least part of the edge portion in the thickness direction perpendicular to the first wall face. The impedance of the first insulating layer is greater than that of the first active material layer, so that the first insulating layer increases the impedance of the edge of the pole piece, limits excessive accumulation of lithium ions in the edge area, reduces the lithium removal speed of cathode lithium ions, and reduces lithium precipitation at the edge of the pole piece.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a pole piece, an electric core and a current collector assembly. Background Art

[0002] While lithium-ion batteries are widely used, they are also subject to increasingly high requirements from consumers, such as high energy density, high charging speed, high endurance, etc. The stacking technology has the advantages of high energy density and high safety due to its high volume utilization rate and more stable internal structure, so it is considered to be one of the most promising technologies in the field of lithium-ion batteries. During the use of lithium-ion batteries, as the number of charge-discharge cycles increases, the single-sided sheets of the positive electrode and the negative electrode will continuously expand and thicken, resulting in the expansion and thickening of the entire battery body; due to the expansion and thickening of the lithium-ion battery core, the lithium-ion battery will squeeze other electronic components during actual use, causing displacement, deformation or even damage to other electronic components, and ultimately making the entire electronic device unable to work properly or even causing safety problems. In the prior art, due to the non-uniform distribution of the current density at the edge of the pole piece, lithium ions concentrate at the edge of the pole piece. Compared with the internal area of the pole piece, lithium ions at the edge are prone to excessive lithium deposition and expansion, affecting the long-term use of the battery core. Summary of the Utility Model

[0003] The main purpose of the utility model is to propose a pole piece, an electric core and a current collector assembly, which can reduce lithium deposition at the edge of the pole piece.

[0004] To achieve the above object, the utility model provides a pole piece, which includes a first substrate, a first active material layer and a first insulating layer. The first substrate has a first wall surface. The first active material layer is coated on the first wall surface, and the first active material layer includes a core part and a side part surrounding the core part. The first insulating layer is coated on the first substrate or the first active material layer, and in the thickness direction perpendicular to the first wall surface, the first insulating layer covers at least part of the side part.

[0005] In some embodiments, the side part includes a first side part and a second side part oppositely arranged along the length direction of the pole piece, and the first insulating layer is coated on the first side part and the second side part.

[0006] In some embodiments, the side part includes a third side part and a fourth side part oppositely arranged along the width direction of the pole piece, and the first insulating layer is coated on the third side part and the fourth side part.

[0007] In some embodiments, the first substrate includes a base and a tab connected to the first substrate, the first active material layer is coated on the first substrate, the direction in which the tab points to the first substrate is the length direction, and the width direction is perpendicular to the length direction and the thickness direction; the first insulating layer has a first coating area and a second coating area arranged opposite to each other along the length direction, and a third coating area and a fourth coating area arranged opposite to each other along the width direction, along the length direction, the first coating area has a first length a, the second coating area has a second length b, along the width direction, the third coating area has a first width c, and the fourth coating area has a second width d; wherein; the first length a is not less than any one of the second length b, the first width c and the second width d.

[0008] In some embodiments, along the length direction, the substrate has a third length e, and along the width direction, the pole piece has a third width f; wherein, the first length a, the second length b, the first width c, the second width d, the third length e and the third width f satisfy: 2.5%≤a / e≤20%; and / or, 1.3%≤b / e≤15%; and / or, 1.7%≤c / e≤30%; and / or, 1.7%≤c / f≤30%; and / or, c=d.

[0009] In some embodiments, the first coating area extends from the edge to the ear, and along the length direction, the overlapping area of ​​the first coating area and the first active material layer has a fourth length g, and the first length a, the second length b, the fourth length g and the third length e satisfy: 1.3%≤g / e≤15%; a≥g; and / or, 2mm≤g≤7mm; and / or, 2mm≤a≤15mm; and / or g=b.

[0010] In some embodiments, along the thickness direction, a first thickness h of the first insulating layer and a second thickness i of the first active material layer satisfy: 0.02≤h / i≤0.6; and / or, 0.5 μm≤h≤5 μm.

[0011] In some embodiments, along the thickness direction, the coating thickness of the first insulating layer is uniform everywhere.

[0012] In some embodiments, the first insulating layer is coated on a side of the first active material layer close to the first substrate; or, the first insulating layer is coated on a side of the first active material layer away from the first substrate; or, the first active material layer includes a first layer and a second layer, the first layer is coated on the first substrate, the first insulating layer is coated on a side of the first layer away from the first substrate, and the second layer is coated on a side of the first insulating layer away from the first layer.

[0013] A second aspect of the present application further provides a battery cell, which includes a pole piece according to any one of the above embodiments.

[0014] The third aspect of the present application further provides a current collector assembly, which is used to cut and form the pole piece of any of the above embodiments. The current collector assembly includes a second substrate, a second active material layer, and a second insulating layer. The second substrate has a second wall surface, the second active material layer is coated on the second wall surface, and the second insulating layer is coated on the second substrate or the second active material layer; wherein the current collector assembly is configured to be able to form at least two pole pieces by die-cutting and dividing the second insulating layer.

[0015] Compared with the prior art, the beneficial effects of the utility model are:

[0016] In the technical solution of the present application, the first insulating layer is coated on the first substrate or the first active material layer, and the first insulating layer covers at least part of the edge along the thickness direction perpendicular to the first wall. Since the impedance of the first insulating layer is greater than the impedance of the first active material layer, the first insulating layer increases the impedance of the edge of the pole piece, limits the excessive accumulation of lithium ions in the edge area, reduces the lithium desorption rate of the cathode lithium ions, and reduces lithium deposition at the edge of the pole piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the structure of a pole piece in an embodiment of the utility model, wherein the first insulating layer is not coated to the pole ear;

[0019] Figure 2 It is a schematic diagram of the structure of a pole piece in an embodiment of the utility model, wherein the first insulating layer is coated to the pole ear;

[0020] Figure 3 It is a schematic diagram of the structure of a pole piece in an embodiment of the utility model, wherein a first insulating layer is coated on a first wall surface;

[0021] Figure 4 This is a schematic diagram of the structure of a pole piece in an embodiment of the utility model, wherein the first insulating layer is coated on a side of the first active material layer away from the first wall surface;

[0022] Figure 5 It is a schematic diagram of the structure of a pole piece in an embodiment of the utility model, wherein the first insulating layer is coated on the first wall surface and extends to the pole ear;

[0023] Figure 6The figure is a schematic structural diagram of a pole piece in an embodiment of the present utility model. Among them, the first insulating layer is coated on the side of the first active material layer facing away from the first wall surface and extends to the tab;

[0024] Figure 7 The figure is a schematic structural diagram of a pole piece in an embodiment of the present utility model. Among them, the first insulating layer is coated between the first layer and the second layer of the first active material layer;

[0025] Figure 8 The figure is a schematic structural diagram of a current collector assembly in an embodiment of the present utility model.

[0026] Explanation of the reference numerals in the drawings:

[0027] Pole piece 100;

[0028] First substrate 110; First wall surface 111; Substrate 112; Tab 113;

[0029] First active material layer 120; Core part 121; Edge part 122; First side part 1221; Second side part 1222; Third side part 1223; Fourth side part 1224; First layer 123; Second layer 124;

[0030] First insulating layer 130; First coating area 131; Second coating area 132; Third coating area 133; Fourth coating area 134;

[0031] Current collector assembly 200;

[0032] Second substrate 210; Second wall surface 211;

[0033] Second active material layer 220;

[0034] Second insulating layer 230;

[0035] Length direction X;

[0036] Width direction Y;

[0037] Thickness direction Z.

[0038] The realization of the purpose, functional characteristics and advantages of the present utility model will be further described with reference to the embodiments and the accompanying drawings. Specific embodiments

[0039] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

[0040] While being widely used, lithium-ion batteries are also subject to increasingly high requirements from consumers, such as high energy density, high charging speed, high endurance, etc. The stacking technology has the advantages of high energy density and high safety due to its high volume utilization rate and more stable internal structure, so it is considered to be one of the most promising technologies in the field of lithium-ion batteries. During the use of lithium-ion batteries, as the number of charge-discharge cycles increases, the single-sided sheets of the positive electrode and the negative electrode will continuously expand and thicken, resulting in the thickening of the entire battery body; due to the expansion and thickening of the lithium-ion battery core, the lithium-ion battery will squeeze other electronic components during actual use, causing displacement, deformation or even damage to other electronic components, and ultimately making the entire electronic device unable to work properly or even leading to safety problems. In the prior art, due to the uneven distribution of the current density at the edge of the electrode sheet, lithium ions are concentrated at the edge of the electrode sheet. Compared with the internal area of the electrode sheet, lithium ions at the edge are prone to excessive lithium deposition and expansion, affecting the long-term use of the battery core.

[0041] To solve the above technical problems, as Figures 1 to 7 shown, the present application proposes an electrode sheet 100, which includes a first substrate 110, a first active material layer 120, and a first insulating layer 130.

[0042] As Figure 1 and Figure 3 shown, the first substrate 110 has a first wall surface 111, and the first substrate 110 is used to carry the active material and transfer electrons. In a lithium-ion battery, the selection of the material of the first substrate 110 has an important impact on both the performance and cost of the battery. Preferably, the electrode sheet 100 is configured as a single-sided negative electrode sheet. The commonly used material for the first substrate 110 of the single-sided negative electrode sheet is copper foil. Copper foil has high conductivity and good mechanical properties, and relatively low cost. If higher energy density is required, the first substrate 110 can also be configured as nickel foil.

[0043] As Figure 2 , Figure 3 and Figure 5 shown, the first active material layer 120 is coated on the first wall surface 111, and the first active material layer 120 includes a core part 121 and a side part 122 surrounding the core part 121. The side part 122 and the core part 121 can be integrally formed. In the technical solution of the present application, the side part 122 refers to the part of the first active material layer 120 that is stacked with the first insulating layer 130 in the thickness direction Z. Specifically, the area coated by the first insulating layer 130 on the first active material layer 120 can be a regular rectangular area, a rectangular area, or any other suitable area.

[0044] In a lithium-ion battery, the electrodes composed of the positive and negative electrode sheets are regarded as a collection of several small capacitors. In a capacitor, the electric field in the middle of the electrode is relatively uniform, and the electric field lines are almost parallel straight lines. However, at the edge of the electrode, due to the influence of the shape, the electric field lines extend from the region between the plates to the external space, changing from parallel lines to an open shape. This non-uniformity of the electric field distribution is mainly concentrated at the edge of the electrode plate, which is the main manifestation of the edge effect of the electrode. Similarly, this edge effect leads to the non-uniformity of the current density distribution at the edge of the lithium-ion battery electrode plate, causing lithium ions to concentrate at the edge of the electrode plate. Compared with the internal region of the electrode plate, lithium ions at the edge are more likely to undergo excessive lithium deposition and swelling. The charge transfer impedance refers to the resistance to the back-and-forth movement of lithium ions between the material and the electrolyte. The magnitude of the charge transfer impedance directly affects the rate of lithium deposition. The technical solution of this application mainly increases the impedance of the cathode edge material by adding an insulating layer at the cathode edge, thereby reducing the lithium ion solubility at the edge while reducing the lithium ion extraction speed, achieving the purpose of improving lithium deposition at the edge. When the impedance at the edge of the electrode plate 100 increases, the resistance of lithium ions to embed in the negative electrode in the edge region also increases, thereby limiting the excessive accumulation of lithium ions in the edge region and reducing the possibility of lithium deposition. In the technical solution of this application, the first insulating layer 130 is coated on the first substrate 110 or the first active material layer 120. Along the thickness direction Z perpendicular to the first wall surface 111, the first insulating layer 130 covers at least part of the edge portion 122. Since the impedance of the first insulating layer 130 is greater than that of the first active material layer 120, the first insulating layer 130 increases the impedance of the edge of the electrode plate 100, limits the excessive accumulation of lithium ions in the edge region, reduces the lithium ion deintercalation speed of the cathode, and reduces lithium deposition.

[0045] In lithium-ion batteries, especially in stacked lithium-ion batteries, due to the presence of a single-sided cathode sheet, with the active material coated on one side of the single-sided cathode sheet, the stress on both sides of the stacked single-sided sheets is uneven. During the charge and discharge process, the problem of lithium deposition and swelling around the electrode plate 100, especially around the periphery of the electrode plate 100, is more prominent. To further solve the problem of aggravated lithium deposition caused by uneven stress around the electrode plate 100, as Figure 1 and Figure 2 shown, in some embodiments, insulating layers are provided around the periphery of the electrode plate 100. Specifically, the edge portion 122 includes a first side portion 1221 and a second side portion 1222 oppositely arranged along the length direction X of the electrode plate 100, and the first insulating layer 130 is coated on the first side portion 1221 and the second side portion 1222; and / or, the edge portion 122 includes a third side portion 1223 and a fourth side portion 1224 oppositely arranged along the width direction Y of the electrode plate 100, and the first insulating layer 130 is coated on the third side portion 1223 and the fourth side portion 1224. The setting of the first insulating layer 130 can increase the impedance of the corresponding region of the edge portion 122 of the electrode plate 100, while improving the stress distribution uniformity around the periphery of the electrode plate 100 and reducing lithium deposition at the edge portion 122 of the electrode plate 100.

[0046] As Figure 1 and Figure 2 shown, further, the first substrate 110 includes a substrate 112 and a tab 113. The tab 113 is connected to the first substrate 110. The first active material layer 120 is coated on the first substrate 110. The direction in which the tab 113 points to the first substrate 110 is the length direction X. The first insulating layer 130 has a first coating area 131 and a second coating area 132 oppositely arranged along the length direction X, and a third coating area 133 and a fourth coating area 134 oppositely arranged along the width direction Y. Along the length direction X, the first coating area 131 has a first length a, and the second coating area 132 has a second length b. Along the width direction Y, the third coating area 133 has a first width c, and the fourth coating area 134 has a second width d. Among them, the first length a is not less than any span of the second length b, the first width c, and the second width d. It should be noted that the first coating area 131 can be a regular shape, such as a rectangular coating area, or an irregularly shaped coating area. The first length a refers to the longest distance between the side of the first coating area 131 close to the tab 113 and the side away from the tab 113 on the straight line perpendicular to the width direction Y along the length direction X. The second length b refers to the longest distance between the side of the second coating area 132 close to the tab 113 and the side away from the tab 113 along the length direction X. The first width c refers to the longest distance of the third coating area 133 along the width direction Y, and the second width d refers to the longest distance of the third coating area 133 along the width direction Y, which will not be elaborated here. Since lithium deposition is more likely to occur on one side of the tab 113 of the electrode 100, the first length a not being less than any span of the second length b, the first width c, and the second width d helps to further reduce lithium deposition at the tab 113 end of the electrode 100.

[0047] As Figure 2As shown, along the length direction X, the substrate 112 has a third length e, and along the width direction Y, the electrode tab 100 has a third width f. The third width f is the total width of the electrode tab 100. The sum of the length of the tab 113 along the length direction X and the third length is the total length of the electrode tab 100. Preferably, the third length e is not less than the third width f. Further, the first length a, the second length b, the first width c, the second width d, the third length e, and the third width f satisfy: 2.5% ≤ a / e ≤ 20%; and / or, 1.3% ≤ b / e ≤ 15%; and / or, 1.7% ≤ c / e ≤ 30%; and / or, 1.7% ≤ c / f ≤ 30%; and / or, c = d. Specifically, a / e can be any suitable ratio such as 2.5%, 3.5%, 5.6%, 7.8%, 9.9%, 10%, 15%, 18%, 20%, etc. b / e can be any suitable ratio such as 1.3%, 1.8%, 2.6%, 3.5%, 9%, 14.2%, or 15%, etc. c / e can be any suitable ratio such as 1.7%, 2.3%, 6.9%, 9.8%, 16.3%, 18.4%, 20%, 25%, 28%, or 30%, etc. c / f can also be any suitable ratio such as 1.7%, 2.3%, 6.9%, 9.8%, 16.3%, 18.4%, 20%, 25%, 28%, or 30%, etc. Preferably, in some embodiments, the first width c and the second width d can be equal, that is to say, the ratio of the second width d to the third length e can be equal to the ratio of the first width c to the third length e. The ratio of the second width d to the third width f can be equal to the ratio of the first width c to the third width f to further improve the stress distribution uniformity at the edge of the electrode tab 100 while increasing the edge impedance of the electrode tab 100.

[0048] As Figure 1 , Figure 3 and Figure 4 shown, the first insulating layer 130 can only cover the substrate 112. As Figure 2 , Figure 5 and Figure 6 shown, the first insulating layer 130 can also extend from the edge 122 on the substrate 112 to the tab 113 to improve the tab strength and reduce tab cutting burrs, etc. As Figure 1 shown, when the first insulating layer 130 only covers the substrate 112, the first length a is equal to the fourth length g. Along the thickness direction Z, the projection of the insulating layer on the first wall surface 111 can be located within the projection of the active material layer on the first wall surface 111, or can extend out of the projection of the active material layer. Preferably, as Figure 2As shown, the projection of the insulating layer extends beyond the projection of the active material layer, that is, the first coating area 131 extends from the edge 122 to the tab 113. Specifically, along the length direction X, the overlapping area of the first coating area 131 and the first active material layer 120 has a fourth length g, and the first length a is the sum of the span of the first coating area 131 on the tab 113 and the fourth length g along the length direction X. Preferably, the first length a, the second length b, the fourth length g, and the third length e satisfy: 1.3% ≤ g / e ≤ 15%; a ≥ g; and / or, 2 mm ≤ g ≤ 7 mm; and / or, 2 mm ≤ a ≤ 15 mm; and / or g = b. Specifically, the value of g / e can be any suitable ratio such as 1.3%, 1.8%, 2.6%, 3.5%, 9%, 14.2%, or 15%. More specifically, the fourth length g can be any suitable value such as 2 mm, 3 mm, 5.5 mm, 6.8 mm, or 7 mm. The first length a can be any suitable value such as 2 mm, 5 mm, 10 mm, 12 mm, or 15 mm. To further improve the stress uniformity of the electrode 100, the fourth length g can also be equal to the second length b.

[0049] Along the thickness direction Z, the first thickness h of the first insulating layer 130 and the second thickness i of the first active material layer 120 satisfy: 0.02 ≤ h / i ≤ 0.6; and / or, 0.5 μm ≤ h ≤ 5 μm. Preferably, the ratio of the first thickness h to the second thickness i can be any suitable value such as 0.02, 0.03, 0.5, 0.1, 0.2, 0.3, 0.5, or 0.6. Preferably, the first thickness h can be any suitable value such as 0.5 μm, 1 μm, 2 μm, 3 μm, 3.5 μm, or 5 μm.

[0050] As Figure 5 shown, to improve the stress uniformity of the electrode 100, the coating thickness of the first insulating layer 130 can be equal everywhere. Specifically, whether the electrode 100 is a single-sided sheet with a single-sided coating of the active material layer or a double-sided sheet with a double-sided coating of the active material layer, the uniform coating thickness of the first insulating layer 130 around the electrode 100 can effectively improve the stress distribution uniformity of the electrode 100.

[0051] According to different coating requirements, as Figure 3 and Figure 5 shown, in some embodiments, the first insulating layer 130 can be coated on the side of the first active material layer 120 close to the first substrate 110. As Figure 4 and Figure 6 shown, in some embodiments, the first insulating layer 130 is coated on the side of the first active material layer 120 facing away from the first substrate 110. As Figure 7As shown, in some embodiments, the first active material layer 120 includes a first layer 123 and a second layer 124. The first layer 123 is coated on the first substrate 110, the first insulating layer 130 is coated on the side of the first layer 123 facing away from the first substrate 110, and the second layer 124 is coated on the side of the first insulating layer 130 facing away from the first layer 123. That is, along the thickness direction Z, the first insulating layer 130 can be single-layer or multi-layer.

[0052] In the technical solution of the present application, the first insulating layer 130 can be selected from non-metallic substances such as boehmite and alumina or polymer substances such as resin. During manufacturing, a high-resistance material such as ceramic or polymer material can be made into a slurry and coated on the first substrate 110 or the side of the first active material layer 120 facing away from the substrate using a gravure roll.

[0053] The first insulating layer 130 being coated on the lower layer means coating the first insulating layer 130 on the first wall surface 111. Correspondingly, the first active material layer 120 is provided on the side of the first insulating layer 130 facing away from the first wall surface 111. The first insulating layer 130 being coated on the upper layer means coating the first insulating layer 130 on the side of the first active material layer 120 facing away from the first wall surface 111. As shown in Table 1, compared with Comparative Example 1 and Comparative Example 2 without the first insulating layer 130, the electrode sheets 100 in Example 1, Example 2, and Example 3 in the present application do not lithium metal deposition, and the solution retention rate is greater than that of the comparative examples, and the swelling rate of the battery cell is also significantly less than that of the comparative examples. Table 1

[0054]

[0055] The second aspect of the present application also provides a battery cell (not shown in the figure). The battery cell includes the electrode sheet 100 of any of the above embodiments. Benefiting from the improvement of the above electrode sheet 100, the battery cell of this embodiment has the same technical effects as the above electrode sheet 100, which will not be elaborated here. Preferably, the battery cell can be prepared by the following method:

[0056] First step, make cathode materials such as lithium cobaltate and ternary materials into a uniform slurry and coat it on the first wall surface 111 provided with the first insulating layer 130; or, coat the slurry uniformly on the first wall surface 111 without the first insulating layer, and then coat a layer of high-resistance material on it; after drying, rolling, and slitting, a cathode single-sided sheet is obtained.

[0057] Second step, coat the first active material layer 120 and the insulating layer again on the side of the first substrate 110 opposite to the first wall surface 111, and after drying, rolling, and slitting again, a cathode double-sided sheet is obtained;

[0058] In the third step, anode materials such as graphite and silicon carbide are made into a uniform slurry, which is coated on the anode current collector. After drying, rolling, and slitting, the anode sheet 100 is obtained.

[0059] In the fourth step, a separator film made of any suitable material such as a polyethylene porous polymer film is selected.

[0060] In the fifth step, a lithium salt and a non-aqueous organic solvent are formulated into a solution as the electrolyte of the lithium battery.

[0061] In the sixth step, each electrode sheet 100 and the separator film are stacked together to make a bare battery cell, and then it is encapsulated and injected with the electrolyte to make a finished lithium-ion battery.

[0062] As Figure 8 shown, in the third aspect of the present application, a current collector assembly 200 is further provided. The current collector assembly 200 is used for cutting to form the electrode sheet 100 of any one of the above embodiments. The current collector assembly 200 includes a second substrate 210, a second active material layer 220, and a second insulating layer 230. The second substrate 210 has a second wall surface 211. The second active material layer 220 is coated on the second wall surface 211, and the second insulating layer 230 is coated on the second substrate 210 or the second active material layer 220. Among them, the current collector assembly 200 is configured to be able to form at least two electrode sheets 100 by die-cutting and dividing the second insulating layer 230. It can be understood that after cutting, the second substrate 210 forms the first substrate 110 and the tab 113, the second active material layer 220 forms the first active material layer 120, and the second insulating layer 230 forms the first insulating layer 130. To improve the convenience of cutting and processing, preferably, the second active material layer 220 can be integrally coated on the second substrate 210. The second insulating layer 230 includes insulating strips extending along the coating direction and in a direction perpendicular to the coating direction and parallel to the second wall surface 211. Cutting the insulating strips can form the electrode sheet 100. It can be understood that in order to leave a cutting margin, the width of the insulating strip is the sum of the widths or lengths of the corresponding sides of the first insulating layer 130 to be formed and the width of the cutting waste, which will not be elaborated here.

[0063] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0064] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present utility model, the descriptions of "first", "second", etc. are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, if "and / or", "or / and", or "and / or" appear throughout the text, their meanings include three parallel scenarios. Taking "A and / or B" as an example, it includes Scenario A, or Scenario B, or the scenario where both A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0065] The above are only the preferred embodiments of the present utility model, and do not limit the patent scope of the present utility model. Any equivalent structural transformation made by using the description of the specification and drawings of the present utility model under the inventive concept of the present utility model, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present utility model.

Claims

1. The pole piece, characterized in that, Comprising: A first substrate having a first wall surface; A first active material layer coated on the first wall surface, the first active material layer including a core portion and a side portion disposed around the core portion; A first insulating layer coated on the first substrate or the first active material layer, and covering at least a part of the side portion in a thickness direction perpendicular to the first wall surface.

2. The electrode tab according to claim 1, wherein The side portion includes a first side portion and a second side portion oppositely disposed along the length direction of the electrode tab, and the first insulating layer is coated on the first side portion and the second side portion; And / or, the side portion includes a third side portion and a fourth side portion oppositely disposed along the width direction of the electrode tab, and the first insulating layer is coated on the third side portion and the fourth side portion.

3. The electrode tab according to claim 1, wherein The first substrate includes a substrate body and a tab connected to the first substrate, the first active material layer is coated on the first substrate, the direction in which the tab points to the first substrate is the length direction, the width direction is perpendicular to the length direction and the thickness direction; the first insulating layer has a first coating area and a second coating area oppositely disposed along the length direction, and a third coating area and a fourth coating area oppositely disposed along the width direction. Along the length direction, the first coating area has a first length a, the second coating area has a second length b, along the width direction, the third coating area has a first width c, and the fourth coating area has a second width d; Wherein; The first length a is not less than any one of the second length b, the first width c, and the second width d.

4. The electrode tab according to claim 3, wherein Along the length direction, the substrate body has a third length e, and along the width direction, the electrode tab has a third width f; wherein, the first length a, the second length b, the first width c, the second width d, the third length e, and the third width f satisfy: 2.5% ≤ a / e ≤ 20%; and / or, 1.3% ≤ b / e ≤ 15%; and / or, 1.7% ≤ c / e ≤ 30%; and / or, 1.7% ≤ c / f ≤ 30%; and / or, c = d.

5. The electrode tab according to claim 4, wherein The first coating area extends from the side portion to the tab, and along the length direction, the overlapping area of the first coating area and the first active material layer has a fourth length g. The first length a, the second length b, the fourth length g, and the third length e satisfy: 1.3% ≤ g / e ≤ 15%; a ≥ g; and / or, 2 mm ≤ g ≤ 7 mm; and / or, 2 mm ≤ a ≤ 15 mm; and / or g = b.

6. The electrode tab according to claim 1, wherein Along the thickness direction, the first thickness h of the first insulating layer and the second thickness i of the first active material layer satisfy: 0.02 ≤ h / i ≤ 0.6; and / or, 0.5 μm ≤ h ≤ 5 μm.

7. The pole piece according to claim 1, wherein along the thickness direction, the coating thickness of the first insulating layer is equal everywhere.

8. The pole piece according to claim 1, wherein the first insulating layer is coated on the side of the first active material layer close to the first substrate; or, the first insulating layer is coated on the side of the first active material layer facing away from the first substrate; or, the first active material layer includes a first layer and a second layer, the first layer is coated on the first substrate, the first insulating layer is coated on the side of the first layer facing away from the first substrate, and the second layer is coated on the side of the first insulating layer facing away from the first layer.

9. The battery cell is characterized in that, Comprising the pole piece according to any one of claims 1 to 8.

10. A current collector assembly for cutting to form the electrode sheet according to any one of claims 1 to 8, characterized in that, The current collector assembly includes: a second substrate having a second wall surface; a second active material layer coated on the second wall surface; a second insulating layer coated on the second substrate or the second active material layer; wherein, the current collector assembly is configured to be able to form at least two of the pole pieces by die-cutting and dividing the second insulating layer.

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