Pole piece, pole core, battery and electric equipment

Abstract

According to the pole piece, the pole core, the battery and the electric equipment, a first coating part and a second coating part are arranged on the same surface of the pole piece in a spaced mode, and a first non-coating part is formed in the area, located between the first coating part and the second coating part, in the pole piece. In the application, the first non-coating part forms the empty foil area, on one hand, the arrangement of the first non-coating area part can improve the liquid phase mass transfer efficiency and increase the liquid phase diffusion capability so as to improve the fast charging capability of the battery after the pole piece is applied to the battery; and on the other hand, the first non-coating area part also provides an extension space for rolling of the pole piece, so that the phenomenon of inconsistent rebound caused by non-uniform surface density after rolling of the pole piece is reduced, the consistency of the pole piece is improved, and the performance of the pole piece is ensured.

Description

Technical Field

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

[0002] With the development of science and technology, battery-powered devices are becoming more and more common in life. Existing batteries include lead-acid batteries, lithium batteries and other types. Among them, lithium-ion batteries have been widely used in electric vehicles, mobile terminals, etc. due to their high energy density and environmental friendliness. Lithium-ion batteries include positive electrodes, separators and negative electrodes. The positive and negative electrodes collect the electrons generated by the electrochemical reaction and conduct them to the external circuit, thereby realizing the process of converting chemical energy into electrical energy.

[0003] In the related art, the battery is limited by the electrode structure and its fast charging capability has certain problems. Utility Model Content

[0004] The purpose of this application is to provide a pole piece, a pole core, a battery and an electrical device to solve the problem of poor fast charging capability of the pole piece.

[0005] To achieve the purpose of this application, this application provides the following technical solutions:

[0006] In a first aspect, the present application provides a pole piece, wherein a first coated portion and a second coated portion are spaced apart on the same surface of the pole piece, and an area of ​​the pole piece located between the first coated portion and the second coated portion forms a first non-coated portion.

[0007] In one embodiment, the pole piece includes a first current collector and a first pole lug, the first coating portion and the second coating portion are both arranged on the same surface of the first current collector, the first pole lug is connected to the first current collector, and the first coating portion is closer to the first pole lug than the second coating portion.

[0008] In one embodiment, a size of the first non-coated portion in a first direction ranges from 1 mm to 3 mm, and the first direction is a direction in which the first coated portion and the second coated portion are arranged.

[0009] In one embodiment, the compaction density of the first coating portion is greater than the compaction density of the second coating portion.

[0010] In one embodiment, the ratio of the compaction density of the first coating portion to the compaction density of the second coating portion is K1,1 <K1≤1.5。

[0011] In one embodiment, the electrode is a positive electrode, and the compaction density of the first coating portion is in the range of 1.8 g / mm 3 ~2.8g / mm3 , and / or, the compaction density range of the second coating portion is 1.8 g / mm 3 ~2.8g / mm 3 ;

[0012] Alternatively, the electrode sheet is a negative electrode sheet, and the compaction density of the first coating portion is in the range of 1.1 g / mm 3 ~1.8g / mm 3 , and / or, the compaction density range of the second coating portion is 1.1 g / mm 3 ~1.8g / mm 3 .

[0013] In one embodiment, the surface density of the first coating portion is greater than the surface density of the second coating portion.

[0014] In one embodiment, a third coating portion is further provided on the same surface of the first current collector, and the first coating portion, the second coating portion and the third coating portion are arranged in sequence along a first direction, and the area in the pole piece located between the second coating portion and the third coating portion forms a second non-coating portion, and the first direction is the direction in which the first coating portion and the second coating portion are arranged.

[0015] In one embodiment, the compaction density of the third coating portion is greater than the compaction density of the second coating portion.

[0016] In one embodiment, a size of the second non-coated portion in the first direction ranges from 1 mm to 3 mm.

[0017] In one embodiment, the ratio of the compaction density of the third coating portion to the compaction density of the second coating portion is K2,1 <K2≤1.5。

[0018] In one embodiment, the electrode is a positive electrode, and the compaction density of the second coating portion is in the range of 1.8 g / mm 3 ~2.8g / mm 3 , and / or the compaction density range of the third coating portion is 1.8 g / mm 3 ~2.8g / mm 3 ;

[0019] Alternatively, the electrode sheet is a negative electrode sheet, and the compaction density of the second coating portion is in the range of 1.1 g / mm 3 ~1.8g / mm 3 , and / or, the compaction density range of the third coating portion is 1.1 g / mm 3 ~1.8g / mm 3 .

[0020] In one embodiment, the surface density of the third coating portion is greater than the surface density of the second coating portion.

[0021] In one embodiment, the compaction density of the first coating portion is the same as the compaction density of the third coating portion.

[0022] In one embodiment, the electrode sheet is a positive electrode sheet, and the surface density range of the first coating portion, the second coating portion, and the third coating portion is 200 g / m 2 ~600g / m 2 ;

[0023] Alternatively, the electrode sheet is a negative electrode sheet, and the surface density range of the first coating portion, the second coating portion, and the third coating portion is 150 g / m 2 ~250g / m 2 .

[0024] In one embodiment, the compaction density of the second coating portion gradually increases from the middle of the second coating portion to one end close to the first coating portion and / or the third coating portion in a first direction, and the first direction is the direction in which the first coating portion and the second coating portion are arranged.

[0025] In one embodiment, the electrode sheet is a positive electrode sheet.

[0026] In a second aspect, the present application further provides a pole core, comprising a pole piece according to the first aspect.

[0027] In one embodiment, the electrode sheet is a positive electrode sheet, and the electrode core further includes a negative electrode sheet. The positive electrode sheet and the negative electrode sheet are stacked along a second direction, and the second direction is the thickness direction of the positive electrode sheet or the negative electrode sheet.

[0028] In one embodiment, the electrode sheet is a positive electrode sheet, and the electrode core further includes a negative electrode sheet, and the positive electrode sheet and the negative electrode sheet are wound to form the electrode core.

[0029] In one embodiment, a fourth coating portion and a fifth coating portion are provided on the same surface of the negative electrode sheet, and the compaction density of the fourth coating portion is greater than the compaction density of the fifth coating portion.

[0030] In one embodiment, the first coated portion and at least a portion of the first non-coated portion are located in an orthographic projection of the fourth coated portion on the positive electrode sheet.

[0031] In one embodiment, the positive electrode sheet includes a first current collector and a first electrode tab, the first electrode tab is connected to one end of the first current collector in a first direction, and the first coating portion is provided on a side of the second coating portion close to the first electrode tab along the first direction;

[0032] The negative electrode sheet comprises a second current collector and a second electrode tab, wherein the second electrode tab is connected to one end of the second current collector along the first direction, and the fourth coating portion is disposed on one side of the fifth coating portion close to the second electrode tab along the first direction;

[0033] The first pole tab and the second pole tab are both located at the same end of the pole core in the first direction.

[0034] In one embodiment, the positive electrode sheet includes a first current collector and a first electrode tab, the first electrode tab is connected to one end of the first current collector in a first direction, and the first coating portion is provided on a side of the second coating portion close to the first electrode tab along the first direction;

[0035] The negative electrode sheet comprises a second current collector and a second electrode tab, wherein the second electrode tab is connected to one end of the second current collector along the first direction, and the fourth coating portion is disposed on a side of the fifth coating portion away from the first electrode tab along the first direction;

[0036] The first pole tab and the second pole tab are respectively located at two ends of the pole core in the first direction.

[0037] In one embodiment, the negative electrode sheet further includes a sixth coating portion, the fifth coating portion is located between the fourth coating portion and the sixth coating portion, and the compaction density of the sixth coating portion is greater than the compaction density of the fifth coating portion.

[0038] In a third aspect, the present application also provides a battery, comprising the pole core according to the second aspect.

[0039] In a fourth aspect, the present application further provides an electrical device, comprising the battery according to the third aspect.

[0040] In the present application, a first coating portion and a second coating portion are spaced apart on the same surface of the pole piece, and a first non-coating portion is formed in the area of ​​the pole piece between the first coating portion and the second coating portion to form a hollow foil area. On the one hand, the provision of the first non-coating portion can improve the liquid phase mass transfer efficiency and increase the liquid phase diffusion capacity to improve the fast charging capability of the battery after the pole piece is applied to the battery; on the other hand, the first non-coating portion also provides an extension space for the pole piece rolling, reduces the rebound inconsistency phenomenon caused by uneven surface density after the pole piece is rolled, improves the consistency of the pole piece, and ensures the performance of the pole piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 This is a schematic diagram of the structure of a battery according to one embodiment of the present application;

[0043] Figure 2 This is a schematic structural diagram of a positive electrode sheet according to an embodiment of the present application;

[0044] Figure 3 A schematic diagram of the structure of a positive electrode sheet and a negative electrode sheet according to an embodiment of the present application.

[0045] Description of reference numerals:

[0046] 100, battery; 110, pole piece; 111, first current collector; 112, first pole tab; 120, negative electrode sheet; 121, second current collector; 122, second pole tab; 130, separator; 141, first coating portion; 142, second coating portion; 143, first non-coating portion; 144, third coating portion; 145, second non-coating portion; 151, fourth coating portion; 152, fifth coating portion; 153, sixth coating portion. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0048] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there can be a central component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there can be a central component at the same time.

[0049] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in this application and in the specification are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this application includes any and all combinations of one or more of the related listed items.

[0050] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0051] The present application provides an electric device, which is a device for converting electrical energy into other forms of energy. The electric device includes electric vehicles, energy storage systems, mobile phones and computers. The electric device provides electrical energy through batteries for the operation of the device.

[0052] For electric vehicles, the electric vehicle includes a frame, a battery and a drive motor, and the battery and the drive motor are installed on the frame. The battery is the main energy source of the vehicle and is used to store and release electrical energy. The battery provides electrical energy to the drive motor to drive the vehicle.

[0053] refer to Figure 1 The present application provides a battery 100, which includes a diaphragm 130 and a pole core, the pole core includes a positive electrode sheet and a negative electrode sheet 120, and the diaphragm 130 is arranged between the positive electrode sheet and the negative electrode sheet 120. The battery 100 also includes a shell and an electrolyte, the shell is used to contain the electrolyte, the diaphragm 130 and the pole core, and the electrolyte serves as a medium for transferring ions. The electrons generated by the electrochemical reaction are collected by the positive electrode sheet and the negative electrode sheet 120 and conducted to the external circuit, thereby realizing the process of converting chemical energy into electrical energy.

[0054] In the related art, the battery is limited by the electrode structure and its fast charging capability has certain problems.

[0055] refer to Figure 1 and Figure 2 The present application provides a pole piece 110, on the same surface of the pole piece 110, a first coating portion 141 and a second coating portion 142 are provided at intervals, and the area between the first coating portion 141 and the second coating portion 142 in the pole piece 110 forms a first non-coating portion 143. Specifically, the first coating portion 141 and the second coating portion 142 contain active materials responsible for storing and releasing energy. In the lithium-ion battery 100, the active material on the positive pole piece can be a transition metal oxide, such as lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, etc.; the active material on the negative pole piece 120 can be graphite, silicon or tin, etc. The first non-coating portion 143 is an area on the pole piece 110 that is not coated with active material. The first non-coating portion 143 can be formed by leaving it empty when the active material is coated on the pole piece 110, or by being erased after the active material is coated.

[0056] In the present application, a first coating portion 141 and a second coating portion 142 are spaced apart on the same surface of the pole piece 110, and a first non-coating portion 143 is formed in the area between the first coating portion 141 and the second coating portion 142 in the pole piece 110 to form an empty foil area. On the one hand, the provision of the first non-coating portion 143 can improve the liquid phase mass transfer efficiency and increase the liquid phase diffusion capacity to improve the fast charging capability of the battery 100 after the pole piece 110 is applied to the battery 100; on the other hand, the first non-coating portion 143 also provides an extension space for the rolling of the pole piece 110, reduces the rebound inconsistency caused by the uneven surface density after the pole piece 110 is rolled, improves the consistency of the pole piece 110, and ensures the performance of the pole piece 110.

[0057] In the electrode sheet 110 provided in the present application, in order to reduce the risk of lithium plating of the electrode core during the charge and discharge process, the first non-coated portion 143 is only designed on the positive electrode sheet, that is, the electrode sheet 110 is a positive electrode sheet.

[0058] The pole piece 110 includes a first current collector 111 and a first pole tab 112. The first coating portion 141 and the second coating portion 142 are both disposed on the same surface of the first current collector 111. The first pole tab 112 is connected to the first current collector 111, and the first coating portion 141 is closer to the first pole tab 112 than the second coating portion 142. The compaction density of the first coating portion 141 is greater than the compaction density of the second coating portion 142, and / or the surface density of the first coating portion 141 is greater than the surface density of the second coating portion 142.

[0059] The first pole ear 112 is a bridge connecting the first current collector 111 and the external circuit to transfer the current inside the battery 100 to the external circuit. The current in the first current collector 111 is gathered toward the first pole ear 112, so that the heat generated near the first pole ear 112 on the first current collector 111 is larger. A first coating portion 141 with a higher compaction density / surface density is provided on one end of the first current collector 111 near the first pole ear 112, which increases the electrochemical impedance of the pole piece 110 near the first pole ear 112, so that more current flows to the middle of the pole piece 110, thereby reducing the heat generated near the first pole ear 112 on the pole piece 110 and reducing the temperature difference on the pole piece 110.

[0060] The compaction density refers to the mass of a substance per unit volume, the surface density refers to the mass of a substance per unit area, and the compaction density is equal to the surface density divided by the thickness of the substance. In the lithium-ion battery 100, the thickness of each coating portion in the pole piece 110 is kept as consistent as possible. When the surface density of the first coating portion 141 is different from that of the second coating portion 142, the compaction density of the first coating portion 141 is also different from that of the second coating portion 142.

[0061] Since the compaction density / surface density of the first coating portion 141 and the second coating portion 142 are inconsistent, when the pole piece 110 is rolled, the pole piece 110 will rebound inconsistently after rolling. By setting the first non-coating portion 143 between the first coating portion 141 and the second coating portion 142, the first non-coating area provides an extension space for rolling the pole piece 110, thereby reducing the inconsistent rebound phenomenon caused by the uneven compaction density / surface density after rolling the pole piece 110, improving the consistency of the pole piece 110, and ensuring the performance of the pole piece 110.

[0062] In the embodiment of the present application, the length direction / width direction of the pole piece 110 is taken as the first direction X, and the thickness direction of the pole piece 110 is taken as the second direction Y.

[0063] In the example of the present application, the first coating portion 141 is closer to the first pole tab 112 than the second coating portion 142. Specifically, in one embodiment, the first coating portion 141 is closer to the edge of the first current collector 111 connected to the first pole tab 112 than at least part of the second coating portion 142. For example, the first coating portion 141 and the second coating portion 142 are both rectangular, and the length of the first coating portion 141 in the vertical first direction X is the same as the length of the second coating portion 142 in the vertical first direction X, then the first coating portion 141 is closer to the edge of the first current collector 111 connected to the first pole tab 112 as a whole than the second coating portion 142, wherein the first direction X is the arrangement direction of the first coating portion 141 and the second coating portion 142, for example, the first direction X can be the length direction of the pole piece 110, and the first direction X can also be the width direction of the pole piece 110. In another embodiment, when the minimum distance from a partial edge of the second coating portion 142 to the edge of the first current collector 111 connected to the first pole ear 112 is the same as the minimum distance from the first coating portion 141 to the edge of the first current collector 111 connected to the first pole ear 112, the first coating portion 141 is arranged opposite to the first pole ear 112 in the first direction X, and the second coating portion 142 is in a "concave" shape, and the second coating portion 142 surrounds the outer periphery of the first coating portion 141.

[0064] Optionally, the first coating portion 141 and the second coating portion 142 are arranged along the first direction X, and the size range of the first non-coated portion 143 in the first direction X is 1 mm to 3 mm, for example, it can be 1 mm, 1.1 mm, 1.25 mm, 1.5 mm, 2 mm, 2.6 mm, 2.8 mm, 3 mm, etc., and is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0065] Optionally, the ratio of the compaction density of the first coating portion 141 to the compaction density of the second coating portion 142 is K1, where 1 < K1 ≤ 1.5. For example, K1 can be 1.01, 1.02, 1.04, 1.07, 1.09, 1.12, 1.15, 1.18, 1.2, etc., but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable. Specifically, when the ratio K1 of the compaction density of the first coating portion 141 to the compaction density of the second coating portion 142 is greater than 1.5, it will result in too large a difference in the dressing thickness between the first coating portion 141 and the second coating portion 142, reducing the feasibility of the actual manufacturing process. At the same time, too large a difference will cause too large a stress difference at different positions of the electrode sheet 110, resulting in frequent tape breakage and cracks due to uneven extension and stress distribution during the rolling and die-cutting processes.

[0066] In the electrode sheet 110 provided in the present application, a third coating portion 144 is further provided on the same surface of the first current collector 111. The first coating portion 141, the second coating portion 142, and the third coating portion 144 are sequentially arranged at intervals along the first direction X. The region of the electrode sheet 110 between the second coating portion 142 and the third coating portion 144 forms a second non-coating portion 145. Specifically, the second non-coating portion 145 forms an empty foil area. The compaction density of the third coating portion 144 is greater than the compaction density of the second coating portion 142, or the areal density of the third coating portion 144 is greater than the areal density of the second coating portion 142. The first coating portion 141 and the third coating portion 144 with a higher compaction density are respectively arranged at both ends of the first current collector 111, and the second coating portion 142 with a lower compaction density tends to distribute a higher current, thereby effectively raising the temperature in the middle of the electrode sheet 110 and making the temperature difference of the electrode sheet 110 smaller.

[0067] Optionally, the size range of the second non-coating portion 145 in the first direction X is 1 mm to 3 mm. For example, it can be 1 mm, 1.1 mm, 1.25 mm, 1.5 mm, 2 mm, 2.6 mm, 2.8 mm, 3 mm, etc., and is not limited to the listed values. Other unlisted values within the numerical range are equally applicable. Among them, the size of the second non-coating portion 145 in the first direction X can be the same as the size of the first non-coating portion 143 in the first direction X.

[0068] Optionally, the ratio of the compaction density of the third coating part 144 to the compaction density of the second coating part 142 is K2, where 1 < K2 ≤ 1.5. For example, K2 can be 1.01, 1.02, 1.04, 1.07, 1.09, 1.12, 1.15, 1.18, 1.2, etc., but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable. Specifically, when the ratio K2 of the compaction density of the third coating part 144 to the compaction density of the second coating part 142 is greater than 1.5, it will cause too large a difference in the dressing thickness between the third coating part 144 and the second coating part 142, resulting in a decrease in the feasibility of the actual manufacturing process. At the same time, the large difference will cause too large a stress difference at different positions of the electrode sheet, and frequent tape breakage and cracks will occur due to uneven extension and stress distribution during the rolling and die-cutting processes.

[0069] In the above embodiment, when the electrode sheet 110 is the positive electrode sheet of the electrode core, and when ensuring that the ratio of the compaction density of the first coating part 141 to the compaction density of the second coating part 142 is K1 and the ratio of the compaction density of the third coating part 144 to the compaction density of the second coating part 142 satisfies the ratio K2, the compaction density range of the first coating part 141 is 1.8 g / mm 3 ~2.8 g / mm 3 , for example, it can be 1.8 g / mm 3 , 1.83 g / mm 3 , 1.85 g / mm 3 , 1.9 g / mm 3 , 2.0 g / mm 3 , 2.05 g / mm 3 , 2.1 g / mm 3 , 2.2 g / mm 3 , 2.25 g / mm 3 , 2.3 g / mm 3 , 2.4 g / mm 3 , 2.45 g / mm 3 , 2.5 g / mm 3 , 2.65 g / mm 3 , 2.7 g / mm 3 , 2.8 g / mm 3 etc., but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable; the compaction density range of the second coating part 142 is 1.8 g / mm 3 ~2.8 g / mm 3 , for example, it can be 1.8 g / mm 3 , 1.83 g / mm 3 , 1.85 g / mm 3 , 1.9 g / mm 3 , 2.0 g / mm 3, 2.05g / mm 3 , 2.1g / mm 3 , 2.2g / mm 3 , 2.25g / mm 3、 2.3g / mm 3 , 2.4g / mm 3 , 2.45g / mm 3 , 2.5g / mm 3 , 2.65g / mm 3 , 2.7g / mm 3 , 2.8g / mm 3 etc., but not limited to the listed values, other values ​​not listed in the numerical range are also applicable; the compaction density range of the third coating portion 144 is 1.8g / mm 3 ~2.8g / mm 3 , for example, it can be 1.8g / mm 3 、1.83g / mm 3 , 1.85g / mm 3 , 1.9g / mm 3 , 2.0g / mm 3 , 2.05g / mm 3 , 2.1g / mm 3 , 2.2g / mm 3 , 2.25g / mm 3 , 2.3g / mm 3 , 2.4g / mm 3 , 2.45g / mm 3 , 2.5g / mm 3 , 2.65g / mm 3 , 2.7g / mm 3 , 2.8g / mm 3 The above values ​​are not limited to the above values, and other values ​​not listed in the above values ​​are also applicable. This ensures the mobility of active material ions in the positive electrode sheet while improving the conductivity.

[0070] When the electrode sheet 110 is a negative electrode sheet of the electrode core, and the ratio of the compaction density of the first coating portion 141 to the compaction density of the second coating portion 142 is K1, and the compaction density of the third coating portion 144 to the compaction density of the second coating portion 142 satisfies the ratio K2, the compaction density range of the first coating portion 141 is 1.1 g / mm 3 ~1.8g / mm 3 , for example, it can be 1.1 g / mm 3 , 1.13g / mm 3 , 1.15g / mm 3 , 1.2g / mm 3, 1.25g / mm 3 , 1.3g / mm 3 , 1.35g / mm 3 , 1.4g / mm 3 , 1.45g / mm 3 , 1.5g / mm 3 , 1.65g / mm 3 , 1.7g / mm 3 , 1.8g / mm 3 etc., but not limited to the listed values, other values ​​not listed in the numerical range are also applicable; the compaction density range of the second coating portion 142 is 1.1 g / mm 3 ~1.8g / mm 3 , for example, it can be 1.1 g / mm 3 , 1.13g / mm 3 , 1.15g / mm 3 , 1.2g / mm 3 , 1.25g / mm 3 , 1.3g / mm 3 , 1.35g / mm 3 , 1.4g / mm 3 , 1.45g / mm 3 , 1.5g / mm 3 , 1.65g / mm 3 , 1.7g / mm 3 , 1.8g / mm 3 etc., but not limited to the listed values, other values ​​not listed in the numerical range are also applicable; the compaction density range of the third coating portion 144 is 1.1 g / mm 3 ~1.8g / mm 3 , for example, it can be 1.1 g / mm 3 , 1.13g / mm 3 , 1.15g / mm 3 , 1.2g / mm 3 , 1.25g / mm 3 , 1.3g / mm 3 , 1.35g / mm 3 , 1.4g / mm 3 , 1.45g / mm 3 , 1.5g / mm 3 , 1.65g / mm 3 , 1.7g / mm 3 , 1.8g / mm 3 The above values ​​are not limited to the above values, and other values ​​not listed in the above values ​​are also applicable. This ensures the mobility of the active material ions in the negative electrode sheet and improves the conductivity.

[0071] In a possible embodiment, the compaction density of the first coating portion 141 is the same as the compaction density of the third coating portion 144. During the manufacturing process of the pole piece 110, the first coating portion 141 and the third coating portion 144 can be coated on the first current collector 111 using the same process to reduce manufacturing difficulty.

[0072] When the electrode sheet 110 is a positive electrode sheet of a core, the surface density range of the first coating portion 141, the second coating portion 142 and the third coating portion 144 is 200 g / m 2 ~600g / m 2 , for example, it can be 200g / m 2 , 210g / m 2 , 220g / m 2 , 240g / m 2 , 280g / m 2 , 300g / m 2 , 400g / m 2 , 450g / m 2 , 500g / m 2 , 520g / m 2 , 580g / m 2 , 600g / m 2 etc., but not limited to the listed values, other values ​​not listed in the numerical range are also applicable. This ensures that there is sufficient active material in the positive electrode sheet while allowing lithium ions to be smoothly inserted and removed.

[0073] When the electrode sheet 110 is a negative electrode sheet of a core, the surface density range of the first coating portion 141, the second coating portion 142 and the third coating portion 144 is 150 g / m 2 ~250g / m 2 . For example, it can be 150g / m 2 , 155g / m 2 , 160g / m 2 , 180g / m 2 , 190g / m 2 , 200g / m 2 , 210g / m 2 , 220g / m 2 , 230g / m 2 , 240g / m 2 , 240g / m 2 , 250g / m 2 etc., but not limited to the listed values, other values ​​not listed in the numerical range are also applicable. This ensures that there is sufficient active material in the negative electrode sheet while allowing lithium ions to be smoothly inserted and removed.

[0074] In the pole piece 110 provided in the present application, the compaction density of the second coating portion 142 gradually increases from the middle of the second coating portion 142 to one end close to the first coating portion 141 and / or the third coating portion 144 in the first direction X, so that the compaction density at the junction of the first coating portion 141 and the second coating portion 142 and at the junction of the second coating portion 142 and the third coating portion 144 gradually changes, so that after the pole piece 110 is rolled, the stress distribution of the pole piece 110 is more uniform.

[0075] refer to Figure 2 and Figure 3 In the pole core provided in the present application, the pole sheet 110 is a positive pole sheet, and the positive pole sheet and the negative pole sheet 120 are stacked along the second direction Y. For the rolled core battery 100, the positive pole sheet and the negative pole sheet 120 are wound to form a pole core.

[0076] The fourth coating part 151 and the fifth coating part 152 are provided on the same surface of the negative electrode sheet 120, and the compaction density of the fourth coating part 151 is greater than the compaction density of the fifth coating part 152. Since the compaction density of the fourth coating part 151 is greater than the compaction density of the fifth coating part 152, the electrochemical impedance of the negative electrode sheet 120 near the first pole ear 112 or the second pole ear 122 is increased, so that more current flows to the middle part of the negative electrode sheet 120, thereby reducing the heat generation of the negative electrode sheet 120 near the first pole ear 112 or the second pole ear 122, so that the temperature difference on the negative electrode sheet 120 is small.

[0077] In addition, in one embodiment, the first coating portion 141 and at least a portion of the first non-coating portion 143 are located in the positive projection of the fourth coating portion 151 on the positive electrode sheet, so that the positive electrode sheet and the negative electrode sheet 120 have corresponding compaction densities, and the capacity of the negative electrode sheet 120 in the coating portion always exceeds the lithium ion embedding sites required by the positive electrode sheet, thereby reducing the risk of lithium plating of the battery 100 during the charging and discharging process.

[0078] In one embodiment, the negative electrode sheet 120 includes a second current collector 121 and a second pole tab 122, the second pole tab 122 is connected to one end of the second current collector 121 along the first direction X, the fourth coating portion 151 is disposed on a side of the fifth coating portion 152 close to the second pole tab 122 along the first direction, and the first pole tab 112 and the second pole tab 122 are both located at the same end of the pole core in the first direction X. In another embodiment, the second pole tab 122 is connected to one end of the second current collector 121 along the first direction X, the fourth coating portion 151 is disposed on a side of the fifth coating portion 152 away from the first pole tab 112 along the first direction X, and the first pole tab 112 and the second pole tab 122 are respectively located at both ends of the pole core in the first direction X. By arranging the first coating portion 141 and the fourth coating portion 151 with higher compaction density near the first pole ear 112 and the second pole ear 122, the second coating portion 142 and the fifth coating portion 152 with lower compaction density tend to distribute a higher current, thereby effectively raising the temperature of the middle part of the pole piece 110 and reducing the temperature difference of the pole piece 110.

[0079] Specifically, the surface of the negative electrode sheet 120 also includes a sixth coating portion 153, the fifth coating portion 152 is located between the fourth coating portion 151 and the sixth coating portion 153, the compaction density of the sixth coating portion 153 is greater than the compaction density of the fifth coating portion 152, and the fourth active coating portion, the fifth coating portion 152 and the sixth coating portion 153 are arranged in sequence along the first direction X, so that part of the heat generated at both ends of the negative electrode sheet 120 is shared to the middle area of ​​the negative electrode sheet 120, so that the temperature distribution of the electrode sheet 110 is uniform and the temperature difference is reduced.

[0080] In the description of the embodiments of the present application, it should be noted that the orientation or positional relationship of terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside" and "outside" are based on the orientation or positional relationship described in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0081] What is disclosed above is only a preferred embodiment of the present application, and it certainly cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of implementing the above embodiment and equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A pole piece, characterized in that: A first coating portion and a second coating portion are disposed at intervals on the same surface of the pole piece, and a region of the pole piece located between the first coating portion and the second coating portion forms a first non-coating portion.

2. The pole piece according to claim 1, characterized in that: The pole piece includes a first current collector and a first pole lug, the first coating portion and the second coating portion are both arranged on the same surface of the first current collector, the first pole lug is connected to the first current collector, and the first coating portion is closer to the first pole lug than the second coating portion.

3. The pole piece according to claim 2, characterized in that: The size of the first non-coated portion in the first direction ranges from 1 mm to 3 mm, and the first direction is the direction in which the first coated portion and the second coated portion are arranged.

4. The pole piece according to claim 2, characterized in that: The compaction density of the first coating portion is greater than the compaction density of the second coating portion.

5. The pole piece according to claim 2, characterized in that: The ratio of the compaction density of the first coating portion to the compaction density of the second coating portion is K1,1 <K1≤1.5。 6. The pole piece according to claim 4 or 5, characterized in that: The electrode sheet is a positive electrode sheet, and the compaction density range of the first coating portion is 1.8 g / mm 3 ~2.8g / mm 3 , and / or, the compaction density range of the second coating portion is 1.8 g / mm 3 ~2.8g / mm 3 ; Alternatively, the electrode sheet is a negative electrode sheet, and the compaction density of the first coating portion is in the range of 1.1 g / mm 3 ~1.8g / mm 3 , and / or, the compaction density range of the second coating portion is 1.1 g / mm 3 ~1.8g / mm 3 .

7. The pole piece according to claim 2, characterized in that: The surface density of the first coating part is greater than the surface density of the second coating part.

8. The pole piece according to claim 2, characterized in that: A third coating portion is also provided on the same surface of the first current collector, and the first coating portion, the second coating portion and the third coating portion are arranged in sequence along the first direction, and the area between the second coating portion and the third coating portion in the pole piece forms a second non-coating portion, and the first direction is the direction in which the first coating portion and the second coating portion are arranged.

9. The pole piece according to claim 8, characterized in that: The compaction density of the third coating portion is greater than the compaction density of the second coating portion.

10. The pole piece according to claim 8, characterized in that: A size of the second non-coated portion in the first direction ranges from 1 mm to 3 mm.

11. The pole piece according to claim 9, characterized in that: The ratio of the compaction density of the third coating portion to the compaction density of the second coating portion is K2,1 <K2≤1.5。 12. The pole piece according to claim 9 or 11, characterized in that: The electrode sheet is a positive electrode sheet, and the compaction density range of the second coating portion is 1.8 g / mm 3 ~2.8g / mm 3 , and / or the compaction density range of the third coating portion is 1.8 g / mm 3 ~2.8g / mm 3 ; Alternatively, the electrode sheet is a negative electrode sheet, and the compaction density of the second coating portion is in the range of 1.1 g / mm 3 ~1.8g / mm 3 , and / or, the compaction density range of the third coating portion is 1.1 g / mm 3 ~1.8g / mm 3 .

13. The pole piece according to claim 8, characterized in that: The surface density of the third coating part is greater than the surface density of the second coating part.

14. The pole piece according to claim 8, characterized in that: The compaction density of the first coating portion is the same as the compaction density of the third coating portion.

15. The pole piece according to claim 8, characterized in that: The electrode sheet is a positive electrode sheet, and the surface density range of the first coating part, the second coating part and the third coating part is 200g / m 2 ~600g / m 2 ; Alternatively, the electrode sheet is a negative electrode sheet, and the surface density range of the first coating portion, the second coating portion, and the third coating portion is 150 g / m 2 ~250g / m 2 .

16. The pole piece according to claim 8, characterized in that: The compaction density of the second coating portion gradually increases from the middle of the second coating portion to one end close to the first coating portion and / or the third coating portion in a first direction, and the first direction is the direction in which the first coating portion and the second coating portion are arranged.

17. The pole piece according to claim 2 or 8, characterized in that: The pole piece is a positive pole piece.

18. A pole core, characterized in that: Comprising a pole piece according to any one of claims 1-17.

19. The pole core according to claim 18, characterized in that: The electrode sheet is a positive electrode sheet, and the electrode core also includes a negative electrode sheet. The positive electrode sheet and the negative electrode sheet are stacked along a second direction, and the second direction is the thickness direction of the positive electrode sheet or the negative electrode sheet.

20. The pole core according to claim 18, characterized in that: The electrode sheet is a positive electrode sheet, and the electrode core also includes a negative electrode sheet. The positive electrode sheet and the negative electrode sheet are wound to form the electrode core.

21. The pole core according to claim 19 or 20, characterized in that: A fourth coating portion and a fifth coating portion are provided on the same surface of the negative electrode sheet, and the compaction density of the fourth coating portion is greater than the compaction density of the fifth coating portion.

22. The pole core according to claim 21, characterized in that: The first coating portion and at least a portion of the first non-coating portion are located in an orthographic projection of the fourth coating portion on the positive electrode sheet.

23. The pole core according to claim 22, characterized in that: The positive electrode sheet comprises a first current collector and a first electrode tab, wherein the first electrode tab is connected to one end of the first current collector in a first direction, and the first coating portion is disposed on a side of the second coating portion close to the first electrode tab along the first direction; The negative electrode sheet comprises a second current collector and a second electrode tab, wherein the second electrode tab is connected to one end of the second current collector along the first direction, and the fourth coating portion is disposed on a side of the fifth coating portion close to the second electrode tab along the first direction; The first pole tab and the second pole tab are both located at the same end of the pole core in the first direction.

24. The pole core according to claim 22, characterized in that: The positive electrode sheet comprises a first current collector and a first electrode tab, wherein the first electrode tab is connected to one end of the first current collector in a first direction, and the first coating portion is disposed on a side of the second coating portion close to the first electrode tab along the first direction; The negative electrode sheet comprises a second current collector and a second electrode tab, wherein the second electrode tab is connected to one end of the second current collector along the first direction, and the fourth coating portion is disposed on a side of the fifth coating portion away from the first electrode tab along the first direction; The first pole tab and the second pole tab are respectively located at two ends of the pole core in the first direction.

25. The pole core according to claim 21, characterized in that: The negative electrode sheet further includes a sixth coating portion, the fifth coating portion is located between the fourth coating portion and the sixth coating portion, and a compaction density of the sixth coating portion is greater than a compaction density of the fifth coating portion.

26. A battery, characterized in that: Comprising a pole core according to any one of claims 18-25.

27. An electrical equipment, characterized in that: Comprising a battery according to claim 26.

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