Electrode sheet, battery, and electrode sheet processing method

Abstract

An electrode sheet, a battery, and an electrode sheet processing method. The electrode sheet comprises a current collector, an active layer, and a first insulating layer. The first insulating layer and the active layer are both coated on a first surface of the current collector, and the first insulating layer comprises a first insulating portion and a second insulating portion. The first insulating portion has a first side edge and a second side edge which are oppositely arranged, the first side edge abuts against the active layer, and the second side edge abuts against the second insulating portion. The second insulating portion is used for cutting processing. Since the first insulating portion is arranged between the second insulating portion and the active layer, and a second thickness b of the second insulating portion is greater than a first thickness a of the first insulating portion, the second insulating portion has a larger thickness, and after cutting, the second insulating portion can effectively improve the compatibility of the insulating layer with burrs formed on a cut surface, thereby reducing the risk of the burrs piercing a separator.

Description

Pole piece, battery and pole piece processing method Technical Field

[0001] The present application relates to the field of battery manufacturing technology, and in particular to a pole piece, a battery, and a pole piece processing method. Background Art

[0002] On the zebra-coated pole piece, an insulating layer is coated on both sides of the active layer on the current collector. During the processing, the pole piece coated with the active layer and the insulating layer needs to be rolled. After rolling, the thickness of the active layer and the insulating layer is reduced, which helps to reduce the thickness of the pole piece and increase the energy density of the pole piece. After rolling, the insulating layer generally needs to be cut to make the pole piece meet the use requirements. When cutting the insulating layer, burrs may be generated on some cut surfaces of the insulating layer. In the battery cell, the thinner the insulating coating, the more likely the burrs generated in the thickness direction of the pole piece are to exceed the coating area and pierce the diaphragm, ultimately leading to a safety problem of a short circuit inside the battery cell. In the prior art, in order to facilitate rolling, the insulating layer generally has a uniform thickness. After cutting, the insulating layer has poor compatibility with burrs, the battery cell diaphragm is easily pierced by burrs, and the battery cell is prone to short circuit.

[0003] Summary of the Invention

[0004] The main purpose of this application is to propose a pole piece, a battery and a pole piece processing method, which can solve the technical problem of poor compatibility of pole piece burrs.

[0005] To achieve the above objectives, the present application proposes a pole piece, which includes a current collector, an active layer, and a first insulating layer. The active layer is coated on the first surface of the current collector. The first insulating layer is coated on the first surface of the current collector, and the first insulating layer includes a first insulating portion and a second insulating portion. The first insulating portion has a first side and a second side that are oppositely arranged. The first side abuts the active layer, and the second side abuts the second insulating portion. The second insulating portion is used for cutting processing. Along a direction perpendicular to the first surface, the first insulating portion has a first thickness a, and the second insulating portion has a second thickness b, wherein the first thickness a and the second thickness b satisfy: b>a.

[0006] In some embodiments, the first thickness a and the second thickness b satisfy: 1<b / a≤1.5.

[0007] In some embodiments, the second insulating portion has a third side and a fourth side that are relatively arranged, the third side abuts the second side, and along the arrangement direction of the active layer and the first insulating layer, there is a first minimum distance c between the first side and the second side, and there is a second minimum distance d between the third side and the fourth side, wherein the first minimum distance c and the second minimum distance d satisfy: 0.5≤d / c≤5.

[0008] In some embodiments, the first minimum distance c and the second minimum distance d satisfy: 1≤d / c≤2.

[0009] In some embodiments, the first minimum distance c and the second minimum distance d satisfy: 1 ​​mm ≤ c + d ≤ 20 mm.

[0010] In some embodiments, the pole piece also includes a second insulating layer, which is arranged on the side of the active layer away from the first insulating layer. The second insulating layer includes a third insulating portion and a fourth insulating portion. One side of the third insulating portion abuts the active layer and the other side abuts the fourth insulating portion. The fourth insulating portion is used for cutting processing. Along the direction perpendicular to the first surface, the third insulating portion has a third thickness e and the fourth insulating portion has a fourth thickness f, wherein the third thickness e and the fourth thickness f satisfy: f>e.

[0011] In some embodiments, the third insulating portion has a fifth side and a sixth side arranged relatively to each other, the fifth side abuts the active layer, and the sixth side abuts the fourth insulating portion. Along the arrangement direction of the active layer and the first insulating layer, the sixth side and the second side have a third minimum distance g, and the first side and the fifth side have a fourth minimum distance h. The third minimum distance g and the fourth minimum distance h satisfy: 0.5mm≤gh≤3.5mm.

[0012] In some embodiments, the third minimum distance g satisfies: 50 mm ≤ g ≤ 500 mm.

[0013] In some embodiments, the fourth minimum distance h satisfies: 50 mm ≤ h ≤ 500 mm.

[0014] A second aspect of the present application further provides a battery, which includes the electrode of any one of the above embodiments.

[0015] The second aspect of the present application further provides a pole piece processing method, which comprises:

[0016] Applying the active layer and the first insulating layer to the first surface of the current collector;

[0017] The active layer and at least a portion of the first insulating layer are rolled to form a first insulating portion and a second insulating portion, wherein the first insulating portion has a first thickness a, the second insulating portion has a second thickness b, and the first thickness a and the second thickness b satisfy: b>a;

[0018] The second insulating portion is cut.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] In the technical solution of the present application, both the first insulating layer and the active layer are coated on the first surface of the current collector. The first insulating layer includes a first insulating portion and a second insulating portion. The first insulating portion has a first side and a second side arranged opposite each other. The first side abuts the active layer, and the second side abuts the second insulating portion. In other words, the first insulating portion is disposed between the second insulating portion and the active layer. The second insulating portion is used for cutting. Because the second thickness b of the second insulating portion is greater than the first thickness a of the first insulating portion, after cutting, the second insulating portion can effectively improve the compatibility of the insulating layer with burrs formed on the cut surface, reducing the risk of burrs piercing the diaphragm. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0022] FIG1 is a schematic diagram of the structure of the zebra coating of the electrode in one embodiment of the present application;

[0023] FIG2 is a schematic structural diagram of a pole piece from a first viewing angle in one embodiment of the present application;

[0024] FIG3 is a schematic structural diagram of a pole piece from a second perspective in one embodiment of the present application, wherein the pole piece is coated with a first insulating layer and a second insulating layer;

[0025] FIG4 is a schematic structural diagram of a pole piece from a second viewing angle in one embodiment of the present application, wherein the pole piece is coated with a first insulating layer;

[0026] FIG5 is a schematic diagram of the structure of a pole piece in an embodiment of the present application, wherein the second pole piece is cut at the edge of the second insulating portion;

[0027] FIG6 is a schematic diagram of the structure of a pole piece in an embodiment of the present application, wherein the second pole piece is cut inside the second insulating portion;

[0028] FIG7 is a flow chart of a method for processing a pole piece in one embodiment of the present application.

[0029] Description of Figure Numbers:

[0030] Pole piece 100;

[0031] Current collector 110; first surface 111; second surface 112;

[0032] active layer 120;

[0033] First insulating layer 130; first insulating portion 131; first side 1311; second side 1312; second insulating portion 132; third side 1321; fourth side 1322;

[0034] Second insulating layer 140; third insulating portion 141; fifth side 1411; sixth side 1412; fourth insulating portion 142;

[0035] First direction X;

[0036] The second direction Y.

[0037] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0039] On the zebra-coated pole piece, an insulating layer is coated on both sides of the active layer on the current collector. During the processing, the pole piece coated with the active layer and the insulating layer needs to be rolled. After rolling, the thickness of the active layer and the insulating layer is reduced, which helps to reduce the thickness of the pole piece and increase the energy density of the pole piece. After rolling, the insulating layer generally needs to be cut to make the pole piece meet the use requirements. When cutting the insulating layer, burrs may be generated on some cut surfaces of the insulating layer. In the battery cell, the thinner the insulating coating, the more likely the burrs generated in the thickness direction of the pole piece are to exceed the coating area and pierce the diaphragm, ultimately leading to a safety problem of a short circuit inside the battery cell. In the prior art, in order to facilitate rolling, the insulating layer generally has a uniform thickness. After cutting, the insulating layer has poor compatibility with burrs, the battery cell diaphragm is easily pierced by burrs, and the battery cell is prone to short circuit.

[0040] To solve the above technical problems, as shown in FIG. 1 to FIG. 6 , the present application provides a pole piece 100 , which includes a current collector 110 , an active layer 120 and a first insulating layer 130 .

[0041] As shown in Figures 1 and 4 , the current collector 110 is used to coat the active layer 120 and the insulating layer. Generally, the current collector 110 has a first surface 111 and a second surface 112 arranged opposite each other. Both the first surface 111 and the second surface 112 can be used to coat the active layer 120 and the insulating layer. For ease of description, the example herein uses the first surface 111 of the current collector 110 coated with the active layer 120 and the insulating layer. In some embodiments, the insulating layer can be configured as a ceramic layer.

[0042] As shown in FIG. 2 and FIG. 4 , the active layer 120 and the first insulating layer 130 are both coated on the first surface 111 of the current collector 110 .

[0043] As shown in Figures 3 and 4, the first insulating layer 130 includes a first insulating portion 131 and a second insulating portion 132. The first insulating portion 131 has a first side 1311 and a second side 1312 that are oppositely disposed. The first side 1311 abuts the active layer 120, and the second side 1312 abuts the second insulating portion 132. In other words, the second insulating portion 132, the first insulating portion 131, and the active layer 120 are sequentially coated on the first surface 111. The second insulating portion 132 is used for cutting. In a direction perpendicular to the first surface 111, the first insulating portion 131 has a first thickness a, and the second insulating portion 132 has a second thickness b, wherein the first thickness a and the second thickness b satisfy: b>a. It can be understood that in the present application, the direction perpendicular to the first surface 111 is the first direction X, and the insulating layer and the active layer 120 have a certain thickness in the first direction X. The arrangement direction of the insulating layer and the active layer 120 is the second direction Y, and the insulating layer and the active layer 120 have a certain width in the second direction Y.

[0044] In the technical solution of the present application, the first insulating layer 130 and the active layer 120 are both coated on the first surface 111 of the current collector 110. The first insulating layer 130 includes a first insulating portion 131 and a second insulating portion 132. The first insulating portion 131 has a first side 1311 and a second side 1312 arranged opposite to each other. The first side 1311 abuts the active layer 120, and the second side 1312 abuts the second insulating portion 132. The second insulating portion 132 is used for cutting. Since the first insulating portion 131 is arranged between the second insulating portion 132 and the active layer 120, and the second thickness b of the second insulating portion 132 is greater than the first thickness a of the first insulating portion 131, the second insulating portion 132 has a greater thickness. After cutting, the second insulating portion 132 can effectively improve the compatibility of the insulating layer with burrs formed on the cut surface, thereby reducing the risk of burrs piercing the diaphragm.

[0045] As shown in Figure 3, the thickness of the first insulating part 131 is less than the thickness of the second insulating part 132. Specifically, the ratio of the thickness of the first insulating part 131 to the thickness of the second insulating part 132 in different pole pieces 100 may vary according to different needs. In this embodiment, the first thickness a and the second thickness b satisfy: 1<b / a≤1.5. Preferably, the ratio of the first thickness a to the second thickness b may satisfy: 1.1≤b / a≤1.3. Specifically, the second thickness b may be 1.05 times, 1.1 times, 1.2 times, 1.25 times, 1.3 times, 1.36 times, 1.4 times, 1.45 times, 1.47 times or 1.5 times the first thickness a, etc., and is not limited here.

[0046] Along the arrangement direction of the insulating layer and the active layer 120, the widths of the first insulating portion 131 and the second insulating portion 132 can also be set separately according to different usage requirements. As shown in Figure 4, in this embodiment, the second insulating portion 132 has a third side 1321 and a fourth side 1322 arranged opposite each other. The third side 1321 abuts the second side 1312. Along the arrangement direction of the active layer 120 and the first insulating layer 130, there is a first minimum distance c between the first side 1311 and the second side 1312, and a second minimum distance d between the third side 1321 and the fourth side 1322. The first minimum distance c and the second minimum distance d satisfy the following relationship: 0.5≤d / c≤5. Specifically, when 0.5≤d / c≤1, the first minimum distance c is not less than the second minimum distance d. That is, along the second direction Y, the width of the first insulating portion 131 can be greater than or equal to the width of the second insulating portion 132. Since the thickness of the first insulating portion 131 is also less than the thickness of the second insulating portion 132, according to different usage requirements, reasonable control of the widths of the first insulating portion 131 and the second insulating portion 132 helps control the overall thickness of the battery cell. Specifically, the ratio of the second minimum distance d to the first minimum distance c can be 0.5, 0.7, 0.9, or 1, and is not limited here. When 1<d / c≤5, the first minimum distance c is less than the second minimum distance d. That is, along the second direction Y, the width of the first insulating portion 131 is less than the width of the second insulating portion 132. The second insulating portion 132 is used for cutting to form the tab connection position, etc., and the cutting of the second insulating portion 132 is generally carried out by laser cutting or metal die cutting. The larger width of the second insulating portion 132 helps to improve the convenience of cutting. Specifically, the second minimum distance d may be 1.2 times, 1.3 times, 1.5 times, 2 times, 3 times, or 5 times the first minimum distance c.

[0047] The second insulating portion 132 is used for cutting processing. In order to facilitate the cutting of the second insulating portion 132 and improve the compatibility of the second insulating portion 132 with burrs after cutting, and at the same time reduce the impact of the second insulating portion 132 on the thickness of the battery cell, the first minimum distance c and the second minimum distance d can satisfy: 1≤d / c≤2. As shown in Figure 4, in this embodiment, the first minimum distance c of the first insulating portion 131 and the second minimum distance d of the second insulating portion 132 satisfy: 1≤d / c≤2. Specifically, the ratio of the first minimum distance c to the second minimum distance d can be any suitable value such as 1, 1.2, 1.5 or 2. The width of the second insulating portion 132 is not less than the width of the first insulating portion 131. The larger cutting width can effectively reduce the difficulty of cutting. After cutting, the second insulating portion 132 can still have a larger width, thereby making the second insulating portion 132 have sufficient strength and improving the compatibility of the second insulating portion 132 with burrs in the thickness direction of the electrode 100. Furthermore, the width ratio of the second insulating portion 132 to the first insulating portion 131 is not greater than 2. After the electrode 100 is applied to the battery cell, the influence of the second insulating portion 132 on the thickness of the battery cell can be reduced.

[0048] According to different usage requirements, the total width of the first insulating part 131 and the second insulating part 132 may be different. As shown in Figure 4, in this embodiment, the first minimum distance c and the second minimum distance d satisfy: 1mm≤c+d≤20mm. That is, along the second direction Y, the total width of the first insulating part 131 and the second insulating part 132 can be 1mm, 2mm, 6mm, 10mm, 15mm or 20mm. Specifically, according to the different ratios of the first minimum distance c and the second minimum distance d, the first minimum distance c and the second minimum distance d can both be 0.5mm; the first minimum distance c can be 3mm, and the corresponding second minimum distance d can be 1.5mm; the first minimum distance c can be 3mm, and the corresponding second minimum distance d can be 6mm, and there is no restriction here.

[0049] During zebra coating, both sides of the active layer 120 can be coated with an insulating layer along the second direction Y. To further improve the compatibility of the pole piece 100 with cutting burrs, the insulating layers on both sides of the active layer 120 can be configured as a step structure. As shown in FIG3 , in this embodiment, the pole piece 100 further includes a second insulating layer 140. The second insulating layer 140 is disposed on a side of the active layer 120 away from the first insulating layer 130. The second insulating layer 140 includes a third insulating portion 141 and a fourth insulating portion 142. One side of the third insulating portion 141 abuts the active layer 120 and the other side abuts the fourth insulating portion 142. The fourth insulating portion 142 is used for cutting processing. Along a direction perpendicular to the first surface 111, the third insulating portion 141 has a third thickness e, and the fourth insulating portion 142 has a fourth thickness f. The third thickness e and the fourth thickness f satisfy: f>e. It is understood that during processing, the active layer 120, the first insulating layer 130, and the second insulating layer 140 can be first coated on the entire first surface 111. After coating, the entire coating layer is directly rolled using a pressure roller, which simultaneously rolls at least a portion of the first insulating layer 130 and at least a portion of the second insulating layer 140, thereby forming the first insulating portion 131 and the second insulating portion 132 on the first insulating layer 130, and forming the third insulating portion 141 and the fourth insulating portion 142 on the second insulating layer 140. Before rolling, the coating thickness of the first insulating layer 130 and the second insulating layer 140 can be equal, and during rolling, the pressure of the pressure roller on the first insulating layer 130 and the second insulating layer 140 can also be equal. Therefore, the thickness of the first insulating portion 131 and the third insulating portion 141 obtained by rolling can be equal, and the thickness of the second insulating portion 132 and the fourth insulating portion 142 can be equal. In some embodiments, the thickness of the first insulating layer 130 may be different from the thickness of the second insulating layer 140 , as long as the second insulating portion 132 and the fourth insulating portion 142 can improve the compatibility of the electrode 100 with burrs.

[0050] The first insulating portion 131, the second insulating portion 132, and the active layer 120 can be rolled simultaneously. Since the longer the roller length along the second direction Y, the more difficult it is to control the consistency of the force applied by the roller to the coating, to ensure more balanced pressure on each portion and a more uniform thickness after rolling, the width of the first insulating portion 131 and the second insulating portion 132 can be no more than 3.5 mm. As shown in FIG2 , in this embodiment, the third insulating portion 141 has a fifth side 1411 and a sixth side 1412 arranged opposite each other. The fifth side 1411 abuts the active layer 120, and the sixth side 1412 abuts the fourth insulating portion 142. Along the arrangement direction of the active layer 120 and the first insulating layer 130, the sixth side 1412 and the second side 1312 have a third minimum distance g, and the first side 1311 and the fifth side 1411 have a fourth minimum distance h. The third minimum distance g and the fourth minimum distance h satisfy the following conditions: 0.5 mm ≤ gh ≤ 3.5 mm. The fourth minimum distance h between the first side 1311 and the fifth side 1411 is the width of the active layer 120 along the second direction Y, and the third minimum distance g between the sixth side 1412 and the second side 1312 is the total width of the first insulating portion 131, the second insulating portion 132, and the active layer 120 in the second direction Y. Specifically, the difference between the third minimum distance g and the fourth minimum distance h can be 0.5 mm, 1 mm, 2 mm, 2.5 mm, 3 mm, or 3.5 mm. It should be noted that the difference between the third minimum distance g and the fourth minimum distance h is the sum of the widths of the first insulating portion 131 and the second insulating portion 132. Depending on different usage requirements, the widths of the first insulating portion 131 and the second insulating portion 132 can be equal or different, and this is not limited here.

[0051] To further improve the consistency of rolling, the actual lengths of the third minimum distance g and the fourth minimum distance h may vary depending on the lengths of different rollers. As shown in Figure 2, in this embodiment, the third minimum distance g may satisfy: 50mm≤g≤500mm. Specifically, the third minimum distance g may be any suitable distance such as 50mm, 100m, 350mm, 475mm or 500mm, in which case the fourth minimum distance h is any distance that satisfies 0.5mm≤gh≤3.5mm. The fourth minimum distance h may satisfy: 50mm≤h≤500mm. Specifically, the fourth minimum distance h may be any suitable distance such as 50mm, 100m, 350mm, 475mm or 500mm, in which case the third minimum distance g is any distance that satisfies 0.5mm≤gh≤3.5mm.

[0052] The second aspect of the present application further provides a battery (not shown), which includes the pole piece 100 of any of the above embodiments. Thanks to the improvement of the pole piece 100, the battery of this embodiment has the same technical effects as the pole piece 100, which will not be described in detail here.

[0053] As shown in FIG7 , the third aspect of the present application further provides a method for processing a pole piece 100 , the method comprising:

[0054] S101: coating the active layer 120 and the first insulating layer 130 on the first surface 111 of the current collector 110;

[0055] S102: Rolling the active layer 120 and at least a portion of the first insulating layer 130 to form a first insulating portion 131 and a second insulating portion 132, wherein the first insulating portion 131 has a first thickness a, and the second insulating portion 132 has a second thickness b, and the first thickness a and the second thickness b satisfy: b>a;

[0056] S103 : cutting the second insulating portion 132 .

[0057] In the step S101: applying the active layer 120 and the first insulating layer 130 to the first surface 111 of the current collector 110, the order of applying the active layer 120 and the first insulating layer 130 can be arbitrary and is not limited herein. In some embodiments, the pole piece 100 may also be coated with a second insulating layer 140, with the first insulating layer 130 and the second insulating layer 140 being disposed on opposite sides of the active layer 120.

[0058] In step S102, a roller rolls at least a portion of the insulating layer. To ensure that the second thickness b of the second insulating portion 132 of the first insulating layer 130 after rolling is greater than the first thickness a of the first insulating portion 131, in some embodiments, the roller may roll the first insulating layer 130 only on the portion of the coating layer of the first insulating layer 130 adjacent to the active layer 120, so that the thickness of the rolled portion of the first insulating layer 130 is less than that of the unrolled portion. In other words, the roller rolls the portion of the first insulating layer 130 adjacent to the active layer 120 to form the first insulating portion 131, while the side of the first insulating layer 130 distal to the active layer 120 is not rolled to form the second insulating portion 132. In some embodiments, the roller may also roll the entire first insulating layer 130. To ensure that the second thickness b after rolling is greater than the first thickness a, the roller may apply greater pressure to the side of the first insulating layer 130 adjacent to the active layer 120 than to the side of the first insulating layer 130 distal to the active layer 120. Specifically, the roller can be configured in various shapes. The roller corresponding to the side of the first insulating layer 130 close to the active layer 120 can have a larger diameter, while the roller corresponding to the side of the first insulating layer 130 away from the active layer 120 can have a smaller diameter. This allows the first insulating layer 130 to form a first insulating portion 131 and a second insulating portion 132 when the roller is rolled against the first insulating layer 130. It should be noted that when the roller is rolled against the active layer 120 and at least a portion of the first insulating layer 130, the thickness of the active layer 120 and the thickness of the first insulating portion 131 after rolling can be equal to or different from each other, and this is not a limitation herein. In some embodiments, the pole piece 100 is sequentially covered with a first insulating layer 130, an active layer 120, and a second insulating layer 140. When the pressing roller rolls the active layer 120 and at least a portion of the first insulating layer 130 and at least a portion of the second insulating layer 140 to form a first insulating portion 131 and a third insulating portion 141, along the second direction Y, the width of the pressing roller is the sum of the widths of the first insulating portion 131, the third insulating portion 141, and the active layer 120.

[0059] In step S103: cutting the second insulating portion 132, the second insulating portion 132 can be cut using either laser die-cutting or metal die-cutting. In the prior art, a pressure roller presses the insulating layer. Due to variations in the deflection of the pressure roller, the end of the insulating layer away from the active layer 120 is prone to overpressure. Excessive pressure from the pressure roller, on the one hand, reduces the thickness of the insulating layer, making it less resistant to burrs. On the other hand, it significantly increases the density of the insulating layer. Laser cutting requires a laser with a higher power and a larger pulse width to cut the insulating layer. During cutting, the insulating layer is also more susceptible to problems such as powder shedding and burrs. As shown in Table 1, for the pole piece with an insulating layer thickness of 40um before rolling, the pole piece is cut with a laser power of 50%, and the average burr value of the cut surface is 2.3um. However, after rolling, the insulating layer with a thickness of 40um after rolling increases in density. When it is cut with a laser power of 50%, the average burr value rises to 14.3um. In order to reduce the average burr value, the cutting laser power is increased to 60%, and the average burr value is 8.3um. The average burr value is still higher than the average value of 2.3um before rolling. Similarly, for a pole piece with an insulating layer thickness of 50um before rolling, the pole piece is cut with a laser power of 50%, and the average burr value of the cut surface is 5.2um. However, after rolling, the insulating layer with a thickness of 40um after rolling increases in density. When it is cut with a laser power of 50%, the average burr value rises to 18.2um. In order to reduce the average burr value, the cutting laser power is increased to 60%, and the average burr value is 10.2um. The average burr value is still higher than the average value of 5.2um when not rolled. It can be seen that the increase in the density of the insulating layer caused by excessive rolling will greatly increase the average burr value after cutting. Obviously, excessive rolling will increase the difficulty of cutting while reducing the thickness of the insulating layer, greatly increasing the burr height, and reducing the compatibility of the insulating layer with burrs. I will not go into details here.

[0060] Table 1

[0061] In the technical solution of the present application, the first insulating layer 130 formed by rolling includes a first insulating portion 131 and a second insulating portion 132. On the one hand, the thickness of the second insulating portion 132 is greater than the thickness of the second insulating portion 132, thereby greatly improving the compatibility of the first insulating layer 130 with burrs. On the other hand, the present application can effectively reduce the excessive rolling of the second insulating portion 132 used for cutting, so that the density of the second insulating portion 132 is less than the density of the first insulating portion 131. The risk of powder loss and burr generation when cutting the second insulating portion 132 is greatly reduced, and the compatibility of the insulating layer with burrs is further improved. It should be noted that when cutting, as shown in Figure 5, the second insulating portion 132 can be cut at the junction of the second insulating portion 132 and the first insulating portion 131 to form a tab connection position. As shown in Figure 6, the second insulating portion 132 can also be cut inside the second insulating portion 132 to form a tab connection position. There is no limitation here.

[0062] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications only explain the relative position relationship, movement status, etc. between the components under a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0063] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only for description purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or", "and / or" or "and / or" appear in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0064] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. All equivalent structural transformations made using the contents of the present application description and drawings under the inventive concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A pole piece, comprising: A current collector; An active layer coated on the first surface of the current collector; A first insulating layer coated on the first surface of the current collector, the first insulating layer includes a first insulating portion and a second insulating portion, the first insulating portion has a first side and a second side arranged oppositely, the first side abuts against the active layer, the second side abuts against the second insulating portion, the second insulating portion is for cutting and processing, along a direction perpendicular to the first surface, the first insulating portion has a first thickness a, the second insulating portion has a second thickness b, wherein, the first thickness a and the second thickness b satisfy: b > a.

2. The pole piece according to claim 1, wherein, The first thickness a and the second thickness b satisfy: 1 < b / a ≤ 1.

5.

3. The pole piece according to claim 1, wherein, The second insulating portion has a third side and a fourth side arranged oppositely, the third side abuts against the second side, along the arrangement direction of the active layer and the first insulating layer, there is a first minimum distance c between the first side and the second side, there is a second minimum distance d between the third side and the fourth side, wherein, the first minimum distance c and the second minimum distance d satisfy: 0.5 ≤ d / c ≤ 5.

4. The pole piece according to claim 3, wherein, The first minimum distance c and the second minimum distance d satisfy: 1 ≤ d / c ≤ 2.

5. The pole piece according to claim 3, wherein, The first minimum distance c and the second minimum distance d satisfy: 1 mm ≤ c + d ≤ 20 mm.

6. The pole piece according to claim 1, wherein, The pole piece further includes a second insulating layer, the second insulating layer is disposed on a side of the active layer away from the first insulating layer, the second insulating layer includes a third insulating portion and a fourth insulating portion, one side of the third insulating portion abuts against the active layer and the other side abuts against the fourth insulating portion, the fourth insulating portion is for cutting and processing, along a direction perpendicular to the first surface, the third insulating portion has a third thickness e, the fourth insulating portion has a fourth thickness f, wherein, the third thickness e and the fourth thickness f satisfy: f > e.

7. The pole piece according to claim 6, wherein, The third insulating portion has a fifth side and a sixth side arranged oppositely, the fifth side abuts against the active layer, the sixth side abuts against the fourth insulating portion, along the arrangement direction of the active layer and the first insulating layer, there is a third minimum distance g between the sixth side and the second side, there is a fourth minimum distance h between the first side and the fifth side has a fourth minimum distance h, the third minimum distance g and the fourth minimum distance h satisfy: 0.5 mm ≤ g - h ≤ 3.5 mm.

8. The pole piece according to claim 7, wherein, The third minimum distance g satisfies: 50 mm ≤ g ≤ 500 mm; Or, The fourth minimum distance h satisfies: 50 mm ≤ h ≤ 500 mm.

9. A battery, wherein, Including the pole piece according to any one of claims 1 to 8.

10. A method for processing a pole piece, wherein, coating an active layer and a first insulating layer on a first surface of a current collector; rolling the active layer and at least a part of the first insulating layer to form a first insulating portion and a second insulating portion, wherein the first insulating portion has a first thickness a, the second insulating portion has a second thickness b, and the first thickness a and the second thickness b satisfy: b > a; cutting the second insulating portion.

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