Electrode sheet, core, battery and electric device

Abstract

An electrode sheet, a core, a battery and an electric device. The battery comprises the core, wherein the core is provided with the electrode sheet, a first coating portion and a second coating portion being spaced apart on the same surface of the electrode sheet, and the area of the electrode sheet located between the first coating portion and the second coating portion forming a first non-coating portion.

Description

Electrode sheets, electrode cores, batteries and electrical equipment

[0001] This application claims priority to Chinese Patent Application No. 202420878777.7, filed on April 24, 2024, entitled "Electrode, Electrode Core, Battery and Electrical Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to the field of battery technology, specifically to an electrode sheet, an electrode core, a battery, and an electrical device. Background Technology

[0003] With the development of science and technology, battery-powered devices are becoming increasingly common in daily life. Existing batteries include various types such as lead-acid batteries and lithium batteries. Among them, lithium-ion batteries are widely used in electric vehicles and mobile terminals due to their advantages such as high energy density and environmental friendliness. A lithium-ion battery consists of a positive electrode, a separator, and a negative electrode. The positive and negative electrodes collect electrons generated by the electrochemical reaction and guide them to an external circuit, thus realizing the conversion of chemical energy into electrical energy.

[0004] In related technologies, batteries are limited by their electrode structure, which limits their fast charging capabilities. Summary of the Invention

[0005] The purpose of this disclosure is to provide an electrode, electrode core, battery, and electrical device to solve the problem of poor fast charging capability of the electrode.

[0006] To achieve the objectives of this disclosure, the following technical solutions are provided:

[0007] In a first aspect, this disclosure provides an electrode sheet, wherein a first coated portion and a second coated portion are provided at intervals on the same surface of the electrode sheet, and a first uncoated portion is formed in the region between the first coated portion and the second coated portion of the electrode sheet.

[0008] In one embodiment, the electrode includes a first current collector and a first tab, the first coating portion and the second coating portion are both disposed on the same surface of the first current collector, the first tab is connected to the first current collector, and the first coating portion is closer to the first tab than the second coating portion.

[0009] In one embodiment, the size of the first uncoated portion in a 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.

[0010] In one embodiment, the compaction density of the first coating portion is greater than the compaction density of the second coating portion.

[0011] 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。

[0012] In one embodiment, the electrode is a positive electrode, and the compaction density of the first coated portion is in the range of 1.8 g / mm². 3 ~2.8g / mm 3 And / or, the compaction density of the second coating portion is in the range of 1.8 g / mm². 3 ~2.8g / mm 3 ;

[0013] Alternatively, the electrode may be a negative electrode, and the compaction density of the first coated portion may be in the range of 1.1 g / mm². 3 ~1.8g / mm 3 And / or, the compaction density of the second coating portion is in the range of 1.1 g / mm². 3 ~1.8g / mm 3 .

[0014] In one embodiment, the areal density of the first coating portion is greater than the areal density of the second coating portion.

[0015] In one embodiment, a third coating portion is further provided on the same surface of the first current collector. The first coating portion, the second coating portion, and the third coating portion are arranged sequentially at intervals along a first direction. The region in the electrode sheet located between the second coating portion and the third coating portion forms a second uncoated portion. The first direction is the direction in which the first coating portion and the second coating portion are arranged.

[0016] In one embodiment, the compaction density of the third coating portion is greater than the compaction density of the second coating portion.

[0017] In one embodiment, the size of the second uncoated portion in the first direction ranges from 1 mm to 3 mm.

[0018] 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。

[0019] 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 / mm². 3 ~2.8g / mm 3 And / or the compaction density of the third coating portion is in the range of 1.8 g / mm². 3 ~2.8g / mm 3 ;

[0020] Alternatively, the electrode may be a negative electrode, and the compaction density of the second coating portion may be in the range of 1.1 g / mm². 3 ~1.8g / mm 3 And / or, the compaction density of the third coating portion is in the range of 1.1 g / mm². 3 ~1.8g / mm 3 .

[0021] In one embodiment, the areal density of the third coating portion is greater than the areal density of the second coating portion.

[0022] In one embodiment, the compaction density of the first coating portion is the same as the compaction density of the third coating portion.

[0023] In one embodiment, the electrode is a positive electrode, and the areal density of the first coating portion, the second coating portion, and the third coating portion are all in the range of 200 g / m². 2 ~600g / m 2 ;

[0024] Alternatively, the electrode is a negative electrode, and the areal density of the first coating portion, the second coating portion, and the third coating portion are all in the range of 150 g / m². 2 ~250g / m 2 .

[0025] In one embodiment, the compaction density of the second coating portion gradually increases from the middle of the second coating portion toward one end near the first coating portion and / or the third coating portion in a first direction, wherein the first direction is the direction in which the first coating portion and the second coating portion are arranged.

[0026] In one embodiment, the electrode is a positive electrode.

[0027] Secondly, this disclosure also provides an electrode core, including the electrode sheet described in the first aspect.

[0028] 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 together along a second direction, which is the thickness direction of the positive electrode sheet or the negative electrode sheet.

[0029] In one embodiment, the electrode sheet is a positive electrode sheet, and the electrode core further includes a negative electrode sheet, wherein the positive electrode sheet and the negative electrode sheet are wound together to form the electrode core.

[0030] In one embodiment, the same surface of the negative electrode sheet is provided with a fourth coating portion and a fifth coating portion, wherein the compaction density of the fourth coating portion is greater than the compaction density of the fifth coating portion.

[0031] In one embodiment, the first coated portion and at least a portion of the first uncoated portion are located in the orthographic projection of the fourth coated portion onto the positive electrode sheet.

[0032] In one embodiment, the positive electrode includes a first current collector and a first tab, the first tab being connected to one end of the first current collector in a first direction, and the first coating portion being disposed on the side of the second coating portion close to the first tab along the first direction;

[0033] The negative electrode includes a second current collector and a second tab, the second tab being connected to one end of the second current collector along the first direction, and the fourth coating portion being disposed on the side of the fifth coating portion along the first direction close to the second tab;

[0034] The first tab and the second tab are both located at the same end of the electrode core in the first direction.

[0035] In one embodiment, the positive electrode includes a first current collector and a first tab, the first tab being connected to one end of the first current collector in a first direction, and the first coating portion being disposed on the side of the second coating portion close to the first tab along the first direction;

[0036] The negative electrode includes a second current collector and a second tab, the second tab being connected to one end of the second current collector along the first direction, and the fourth coating portion being disposed on the side of the fifth coating portion away from the first tab along the first direction;

[0037] The first tab and the second tab are located at opposite ends of the electrode core in the first direction.

[0038] In one embodiment, the negative electrode further includes a sixth coating portion, the fifth coating portion being located between the fourth coating portion and the sixth coating portion, and the compaction density of the sixth coating portion being greater than the compaction density of the fifth coating portion.

[0039] Thirdly, this disclosure also provides a battery including the electrode core as described in the second aspect.

[0040] Fourthly, this disclosure also provides an electrical device including the battery described in the third aspect.

[0041] In this disclosure, by providing a first coating portion and a second coating portion at intervals on the same surface of the electrode, a first uncoated portion is formed in the region between the first coating portion and the second coating portion of the electrode to form an empty foil area. On the one hand, the provision of the first uncoated portion can improve the liquid phase mass transfer efficiency and increase the liquid phase diffusion capability to improve the fast charging capability of the battery after the electrode is applied to the battery. On the other hand, the first uncoated portion also provides extension space for the electrode rolling, reducing the rebound inconsistency caused by uneven surface density after the electrode rolling, improving the consistency of the electrode, and ensuring the performance of the electrode. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 is a schematic diagram of the structure of a battery according to an embodiment of the present disclosure;

[0044] Figure 2 is a schematic diagram of the structure of a positive electrode sheet according to an embodiment of the present disclosure;

[0045] Figure 3 is a schematic diagram of the structure of the positive electrode and the negative electrode according to one embodiment of the present disclosure;

[0046] Figure 4 is a schematic diagram of the structure of an electrical device according to one embodiment of the present disclosure.

[0047] Explanation of reference numerals in the attached drawings: 100, battery; 110, electrode; 111, first current collector; 112, first tab; 120, negative electrode; 121, second current collector; 122, second tab; 130, separator; 141, first coating section; 142, second coating section; 143, first uncoated section; 144, third coating section; 145, second uncoated section; 151, fourth coating section; 152, fifth coating section; 153, sixth coating section; 200, electrical equipment. Detailed Implementation

[0048] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0049] 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 it can be in a middle component. When a component is said to be "connected" to another component, it can be directly connected to the other component or it may be in a middle component.

[0050] Unless otherwise defined, all technical and scientific terms used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used in the specification of this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The term "and / or" as used in this disclosure includes any and all combinations of one or more of the associated listed items.

[0051] The following detailed description of some embodiments of this disclosure is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0052] Referring to Figure 4, this disclosure provides an electrical device 200, which is a device for converting electrical energy into other forms of energy. The electrical device 200 includes electric vehicles, energy storage systems, mobile phones, and computers. The electrical device 200 is powered by a battery 100 to operate the device.

[0053] For electric vehicles, the components include a frame, a battery, and a drive motor, with the battery and drive motor mounted on the frame. The battery, as the vehicle's primary energy source, stores and releases electrical energy. The battery provides power to the drive motor, propelling the vehicle.

[0054] Referring to Figure 1, this disclosure provides a battery 100, which includes a separator 130 and an electrode core. The electrode core includes a positive electrode and a negative electrode 120, and the separator 130 is disposed between the positive electrode and the negative electrode 120. The battery 100 also includes a casing and an electrolyte. The casing is used to contain the electrolyte, the separator 130, and the electrode core, and the electrolyte serves as a medium for ion transfer. Electrons generated by the electrochemical reaction are collected by the positive and negative electrode 120 and conducted to an external circuit, thereby realizing the conversion of chemical energy into electrical energy.

[0055] In related technologies, batteries are limited by their electrode structure, which limits their fast charging capabilities.

[0056] Referring to Figures 1 and 2, this disclosure provides an electrode 110. A first coating portion 141 and a second coating portion 142 are spaced apart on the same surface of the electrode 110. A first uncoated portion 143 is formed in the area between the first coating portion 141 and the second coating portion 142 of the electrode 110. Specifically, the first coating portion 141 and the second coating portion 142 contain active material responsible for storing and releasing energy. In the lithium-ion battery 100, the active material on the positive electrode can be a transition metal oxide, such as lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, etc.; the active material on the negative electrode 120 can be graphite, silicon, or tin, etc. The first uncoated portion 143 is the area on the electrode 110 where no active material is coated. The first uncoated portion 143 can be formed by leaving space during the coating of the active material on the electrode 110, or by erasing after the active material is coated.

[0057] In this disclosure, by providing a first coating portion 141 and a second coating portion 142 at intervals on the same surface of the electrode 110, a first uncoated portion 143 is formed in the region of the electrode 110 located between the first coating portion 141 and the second coating portion 142 to form an empty foil area. On the one hand, the provision of the first uncoated portion 143 can improve the liquid phase mass transfer efficiency and increase the liquid phase diffusion capability to improve the fast charging capability of the battery 100 after the electrode 110 is applied; on the other hand, the first uncoated portion 143 also provides extension space for the rolling of the electrode 110, reduces the inconsistent rebound phenomenon caused by uneven surface density after the electrode 110 is rolled, improves the consistency of the electrode 110, and ensures the performance of the electrode 110.

[0058] In the electrode 110 provided in this disclosure, in order to reduce the risk of lithium plating in the electrode core during the charging and discharging process, the first uncoated portion 143 is designed only on the positive electrode, that is, the electrode 110 is a positive electrode.

[0059] The electrode 110 includes a first current collector 111 and a first tab 112. A first coating portion 141 and a second coating portion 142 are both disposed on the same surface of the first current collector 111. The first tab 112 is connected to the first current collector 111, and the first coating portion 141 is closer to the first 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 areal density of the first coating portion 141 is greater than the areal density of the second coating portion 142.

[0060] The first tab 112 serves as a bridge connecting the first current collector 111 and the external circuit, transferring the current inside the battery 100 to the external circuit. The current in the first current collector 111 converges towards the first tab 112, resulting in greater heat generation on the first current collector 111 near the first tab 112. A first coating portion 141 with a high compaction density / area density is provided on the end of the first current collector 111 near the first tab 112, increasing the electrochemical resistance of the electrode 110 near the first tab 112, allowing more current to flow to the middle of the electrode 110, thereby reducing the heat generation on the electrode 110 near the first tab 112 and making the temperature difference on the electrode 110 smaller.

[0061] Here, compaction density refers to the mass of a substance per unit volume, and areal density refers to the mass of a substance per unit area. Compaction density equals areal density divided by the thickness of the substance. In the lithium-ion battery 100, the thickness of each coating portion in the electrode 110 is kept as consistent as possible. When the areal densities of the first coating portion 141 and the second coating portion 142 are different, the compaction densities of the first coating portion 141 and the second coating portion 142 are also different.

[0062] Because the compaction density / area density of the first coating section 141 and the second coating section 142 are inconsistent, the electrode 110 will exhibit inconsistent rebound after rolling. By providing a first uncoated section 143 between the first coating section 141 and the second coating section 142, the first uncoated area provides extension space for the electrode 110 during rolling, reducing the inconsistent rebound caused by the uneven compaction density / area density after rolling, improving the consistency of the electrode 110, and ensuring the performance of the electrode 110.

[0063] In this embodiment of the disclosure, the length / width direction of the electrode 110 is taken as the first direction X, and the thickness direction of the electrode 110 is taken as the second direction Y.

[0064] In the disclosed example, the first coating part 141 is closer to the first tab 112 than the second coating part 142. Specifically, in one implementation, at least a part of the first coating part 141 is closer to the edge of the first current collector 111 where the first tab 112 is connected than the second coating part 142. For example, both the first coating part 141 and the second coating part 142 are rectangular, and the length of the first coating part 141 in the direction perpendicular to the first direction X is the same as the length of the second coating part 142 in the direction perpendicular to the first direction X. Then, the first coating part 141 as a whole is closer to the edge of the first current collector 111 where the first tab 112 is connected than the second coating part 142. Here, the first direction X is the arrangement direction of the first coating part 141 and the second coating part 142. For example, the first direction X can be the length direction of the electrode sheet 110, or the first direction X can also be the width direction of the electrode sheet 110. In another implementation, when the minimum distance from a part of the edge of the second coating part 142 to the edge of the first current collector 111 where the first tab 112 is connected is the same as the minimum distance from the first coating part 141 to the edge of the first current collector 111 where the first tab 112 is connected, the first coating part 141 is disposed opposite to the first tab 112 in the first direction X, and the second coating part 142 is in a "concave" shape and surrounds the outer periphery of the first coating part 141.

[0065] Optionally, the first coating part 141 and the second coating part 142 are arranged along the first direction X, and the size range of the first non - coating part 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. It is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0066] Optionally, 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 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 it is not limited to the listed values, and other unlisted values within the numerical range are also applicable. Specifically, when the ratio K1 of the compaction density of the first coating part 141 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 first coating part 141 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 110, and frequent tape breakage and cracks will occur due to uneven extension and stress distribution during the rolling and die - cutting processes.

[0067] In the electrode sheet 110 provided by the present disclosure, 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. An area between the second coating portion 142 and the third coating portion 144 in the electrode sheet 110 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 that of the second coating portion 142, or the areal density of the third coating portion 144 is greater than that of the second coating portion 142. The first coating portion 141 and the third coating portion 144 with higher compaction densities 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.

[0068] 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.

[0069] Optionally, the ratio of the compaction density of the third coating portion 144 to the compaction density of the second coating portion 142 is K2, and 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. Other unlisted values within the numerical range are equally applicable. Specifically, when the ratio K2 of the compaction density of the third coating portion 144 to the compaction density of the second coating portion 142 is greater than 1.5, it will cause too large a difference in the dressing thickness between the third coating portion 144 and the second coating portion 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, resulting in frequent tape breakage and cracks due to uneven extension and stress distribution during the rolling and die - cutting processes.

[0070] In the above - mentioned 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 portion 141 to the compaction density of the second coating portion 142 is K1 and the ratio of the compaction density of the third coating portion 144 to the compaction density of the second coating portion 142 satisfies the ratio K, the compaction density range of the first coating portion 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 31.85g / 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 And, but not limited to, the listed values, other unlisted values ​​within the range also apply; the compaction density of the second coating section 142 is 1.8 g / mm². 3 ~2.8g / mm 3 For example, it could 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 And, but not limited to, the listed values, other unlisted values ​​within the range also apply; the compaction density of the third coating section 144 is 1.8 g / mm². 3 ~2.8g / mm 3 For example, it could 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 32.25g / 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 And so on, but not limited to the values ​​listed; other unlisted values ​​within the range also apply. This is to improve conductivity while ensuring the migration speed between active material ions in the positive electrode.

[0071] When the electrode 110 is the negative electrode with the electrode core, and ensuring that 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 ratio of the compaction density of the third coating portion 144 to the compaction density of the second coating portion 142 is K2, the compaction density range of the first coating portion 141 is 1.1 g / mm². 3 ~1.8g / mm 3 For example, it could 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 And, but not limited to, the listed values, other unlisted values ​​within the range also apply; the compaction density of the second coating section 142 is 1.1 g / mm². 3 ~1.8g / mm 3 For example, it could 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 31.65g / mm 3 1.7g / mm 3 1.8g / mm 3 And, but not limited to, the listed values, other unlisted values ​​within the range also apply; the compaction density of the third coating section 144 is 1.1 g / mm². 3 ~1.8g / mm 3 For example, it could 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 And so on, but not limited to the values ​​listed; other unlisted values ​​within the range also apply. This is to improve conductivity while ensuring the migration speed between ions of the active material in the negative electrode.

[0072] In one possible implementation, the compaction density of the first coating portion 141 is the same as that of the third coating portion 144. During the manufacturing process of the electrode 110, the same process can be used to coat the first coating portion 141 and the third coating portion 144 on the first current collector 111 to reduce the manufacturing difficulty.

[0073] When the electrode 110 is the positive electrode core, the areal density range of the first coating part 141, the second coating part 142, and the third coating part 144 is all 200 g / m². 2 ~600g / m 2 For example, it could 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 2And so on, but not limited to the values ​​listed; other unlisted values ​​within the range also apply. This ensures that there is sufficient active material in the positive electrode while allowing lithium ions to intercalate and deintercalate smoothly.

[0074] When the electrode 110 is the negative electrode core, the areal density range of the first coating part 141, the second coating part 142, and the third coating part 144 is all 150 g / m². 2 ~250g / m 2 For example, it could be 150g / m³. 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 And so on, but not limited to the values ​​listed; other unlisted values ​​within the range also apply. This ensures that there is sufficient active material in the negative electrode while allowing lithium ions to intercalate and deintercalate smoothly.

[0075] In the electrode 110 provided in this disclosure, the compaction density of the second coating portion 142 gradually increases from the middle of the second coating portion 142 toward one end near 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, thereby making the stress distribution of the electrode 110 more uniform after the electrode 110 is rolled.

[0076] Referring to Figures 2 and 3, in the electrode core provided in this disclosure, electrode 110 is a positive electrode, and the positive electrode and negative electrode 120 are stacked along the second direction Y. For the wound cell 100, the positive electrode and negative electrode 120 are wound to form the electrode core.

[0077] The negative electrode 120 has a fourth coating portion 151 and a fifth coating portion 152 on the same surface. The compaction density of the fourth coating portion 151 is greater than that of the fifth coating portion 152. By increasing the compaction density of the fourth coating portion 151, the electrochemical resistance of the negative electrode 120 near the first tab 112 or the second tab 122 is increased, allowing more current to flow to the middle of the negative electrode 120. This reduces the heat generation near the first tab 112 or the second tab 122, resulting in a smaller temperature difference on the negative electrode 120.

[0078] Furthermore, in one embodiment, the first coated portion 141 and at least a portion of the first uncoated portion 143 are located in the orthogonal projection of the fourth coated portion 151 onto the positive electrode, thereby ensuring that the capacity of the negative electrode 120 within the corresponding compaction density coated portion of the positive and negative electrode 120 always exceeds the lithium-ion insertion sites required by the positive electrode, reducing the risk of lithium plating during the charging and discharging process of the battery 100.

[0079] In one embodiment, the negative electrode 120 includes a second current collector 121 and a second tab 122. The second tab 122 is connected to one end of the second current collector 121 along a first direction X. A fourth coating portion 151 is disposed on the side of the fifth coating portion 152 along the first direction near the second tab 122. The first tab 112 and the second tab 122 are both located at the same end of the electrode core in the first direction X. In another embodiment, the second 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 the side of the fifth coating portion 152 along the first direction X away from the first tab 112. The first tab 112 and the second tab 122 are respectively located at opposite ends of the electrode core in the first direction X. By providing a first coating portion 141 and a fourth coating portion 151 with higher compaction density near the first tab 112 and the second tab 122, the second coating portion 142 and the fifth coating portion 152 with lower compaction density tend to distribute higher current, thereby effectively raising the temperature of the middle part of the electrode 110 and reducing the temperature difference of the electrode 110.

[0080] Specifically, the surface of the negative electrode 120 also includes a sixth coating portion 153, and a 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 that of the fifth coating portion 152. The fourth coating portion, the fifth coating portion 152 and the sixth coating portion 153 are arranged sequentially along the first direction X, so that part of the heat generated at both ends of the negative electrode 120 is distributed to the middle area of ​​the negative electrode 120, thereby making the temperature distribution of the electrode 110 uniform and the temperature difference smaller.

[0081] In the description of the embodiments of this disclosure, it should be noted that the orientation or positional relationship of the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and other indicators are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0082] The above-disclosed embodiments are merely preferred embodiments of this disclosure and should not be construed as limiting the scope of this disclosure. Those skilled in the art will understand that all or part of the processes for implementing the above embodiments, and equivalent variations made in accordance with the claims of this disclosure, still fall within the scope of this disclosure.

Claims

1. An electrode sheet, comprising a first coating portion (141) and a second coating portion (142) spaced apart on the same surface of the electrode sheet (110), wherein a first uncoated portion (143) is formed in the region between the first coating portion (141) and the second coating portion (142) of the electrode sheet (110).

2. The electrode according to claim 1, comprising: the electrode (110) including a first current collector (111) and a first tab (112), the first coating portion (141) and the second coating portion (142) being disposed on the same surface of the first current collector (111), the first tab (112) being connected to the first current collector (111), and the first coating portion (141) being closer to the first tab (112) than the second coating portion (142).

3. The electrode sheet according to claim 1 or 2, comprising, wherein the size of the first uncoated portion (143) in a first direction is in the range of 1 mm to 3 mm, and the first direction is the direction in which the first coated portion (141) and the second coated portion (142) are arranged.

4. The electrode according to any one of claims 1-3, wherein the compaction density of the first coating portion (141) is greater than the compaction density of the second coating portion (142).

5. The electrode sheet according to any one of claims 1-4, wherein the ratio of the compaction density of the first coating portion (141) to the compaction density of the second coating portion (142) is K1,1 <K1≤1.5。 6. The electrode according to claim 4 or 5, wherein the electrode (110) is a positive electrode, and the compaction density of the first coating portion (141) is in the range of 1.8 g / mm². 3 ~2.8g / mm 3 And / or, the compaction density of the second coating portion (142) is in the range of 1.8 g / mm². 3 ~2.8g / mm 3 ; Alternatively, the electrode (110) may be a negative electrode (120), and the compaction density of the first coating portion (141) may be in the range of 1.1 g / mm². 3 ~1.8g / mm 3 And / or, the compaction density of the second coating portion (142) is in the range of 1.1 g / mm². 3 ~1.8g / mm 3 .

7. The electrode according to any one of claims 1-3, wherein the areal density of the first coating portion (141) is greater than the areal density of the second coating portion (142).

8. The electrode according to any one of claims 2-7, comprising: a third coating portion (144) 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) being arranged sequentially at intervals along a first direction; a second uncoated portion (145) being formed in the region between the second coating portion (142) and the third coating portion (144) in the electrode (110); the first direction being the direction in which the first coating portion (141) and the second coating portion (142) are arranged.

9. The electrode according to claim 8, wherein the compaction density of the third coating portion (144) is greater than the compaction density of the second coating portion (142).

10. The electrode according to claim 8 or 9, wherein the second uncoated portion (145) has a size ranging from 1 mm to 3 mm in the first direction.

11. The electrode according to any one of claims 8-10, wherein the ratio of the compaction density of the third coating portion (144) to the compaction density of the second coating portion (142) is K2. <K2≤1.5。 12. The electrode according to claim 9 or 11, wherein the electrode (110) is a positive electrode, and the compaction density of the second coating portion (142) is in the range of 1.8 g / mm². 3 ~2.8g / mm 3 And / or the compaction density of the third coating portion (144) is in the range of 1.8 g / mm². 3 ~2.8g / mm 3 ; Alternatively, the electrode (110) may be a negative electrode (120), and the compaction density of the second coating portion (142) may be in the range of 1.1 g / mm². 3 ~1.8g / mm 3 And / or, the compaction density of the third coating portion (144) is in the range of 1.1 g / mm². 3 ~1.8g / mm 3 .

13. The electrode according to any one of claims 8-12, wherein the areal density of the third coating portion (144) is greater than the areal density of the second coating portion (142).

14. The electrode according to any one of claims 8-13, wherein the compaction density of the first coating portion (141) is the same as the compaction density of the third coating portion (144).

15. The electrode according to any one of claims 8-14, comprising: the electrode (110) being a positive electrode; and the areal density of the first coating portion (141), the second coating portion (142), and the third coating portion (144) all being in the range of 200 g / m³. 2 ~600g / m 2 ; Alternatively, the electrode (110) may be a negative electrode (120), and the areal density of the first coating portion (141), the second coating portion (142), and the third coating portion (144) may all be in the range of 150 g / m². 2 ~250g / m 2 .

16. The electrode according to any one of claims 8-15, comprising, wherein the compaction density of the second coating portion (142) gradually increases in a first direction from the middle of the second coating portion (142) toward one end near the first coating portion (141) and / or the third coating portion (144), the first direction being the direction in which the first coating portion (141) and the second coating portion (142) are arranged.

17. The electrode according to any one of claims 1-16, wherein the electrode (110) is a positive electrode.

18. An electrode core comprising an electrode sheet (110) according to any one of claims 1-17.

19. The electrode core according to claim 18, wherein the electrode sheet (110) is a positive electrode sheet, the electrode core further includes a negative electrode sheet (120), the positive electrode sheet and the negative electrode sheet (120) are stacked along a second direction, the second direction being the thickness direction of the positive electrode sheet or the negative electrode sheet (120).

20. The electrode core according to claim 18, wherein the electrode sheet (110) is a positive electrode sheet, and the electrode core further includes a negative electrode sheet (120), wherein the positive electrode sheet and the negative electrode sheet (120) are wound together to form the electrode core.

21. The electrode core according to claim 19 or 20, comprising a fourth coating portion (151) and a fifth coating portion (152) on the same surface of the negative electrode sheet (120), wherein the compaction density of the fourth coating portion (151) is greater than the compaction density of the fifth coating portion (152).

22. The electrode core according to claim 21, comprising the first coated portion (141) and at least a portion of the first uncoated portion (143) located in the orthographic projection of the fourth coated portion (151) onto the positive electrode sheet.

23. The electrode core according to claim 21 or 22, comprising, wherein the positive electrode sheet includes a first current collector (111) and a first tab (112), the first tab (112) being connected to one end of the first current collector (111) in a first direction, and the first coating portion (141) being disposed on the side of the second coating portion (142) along the first direction close to the first tab (112); The negative electrode (120) includes a second current collector (121) and a second tab (122), the second tab (122) being connected to one end of the second current collector (121) along the first direction, and the fourth coating portion (151) being disposed on the side of the fifth coating portion (152) along the first direction close to the second tab (122); The first tab (112) and the second tab (122) are both located at the same end of the pole core in the first direction.

24. The electrode core according to claim 21 or 22, comprising, wherein the positive electrode sheet comprises a first current collector (111) and a first tab (112), the first tab (112) being connected to one end of the first current collector (111) in a first direction, and the first coating portion (141) being disposed on the side of the second coating portion (142) along the first direction close to the first tab (112); The negative electrode (120) includes a second current collector (121) and a second tab (122), the second tab (122) being connected to one end of the second current collector (121) along the first direction, and the fourth coating portion (151) being disposed on the side of the fifth coating portion (152) away from the first tab (112) along the first direction; The first tab (112) and the second tab (122) are located at the two ends of the electrode core in the first direction, respectively.

25. The electrode core according to claim 21 or 22, comprising, wherein the negative electrode sheet (120) further comprises a sixth coating portion (153), the fifth coating portion (152) being located between the fourth coating portion (151) and the sixth coating portion (153), wherein the compaction density of the sixth coating portion (153) is greater than the compaction density of the fifth coating portion (152).

26. A battery comprising an electrode core according to any one of claims 18-25.

27. An electrical appliance comprising the battery (100) according to claim 26.

Images