Current collector, pole piece, battery cell, battery and electric equipment

Abstract

The utility model provides a current collector, a pole piece, a battery cell, a battery and electric equipment, and relates to the technical field of batteries. The current collector comprises a main body part, and the end part of the main body part is connected with a tab part of the pole piece; two opposite sides of the main body part are provided with coating surfaces, each coating surface comprises a plurality of coating areas distributed along the length direction of the current collector, and the coating area on at least one side is used for coating a dressing; and in the length direction of the main body part, the contact area of the coating area close to one side of the tab part and the dressing is larger than the contact area of the coating area far away from one side of the tab part and the dressing. According to the present invention, the contact area between the current collector close to the tab and the dressing can be increased, such that the contact resistance at the tab can be easily reduced, the problem of easy lithium precipitation at the tab of the high-rate rapid charging battery can be alleviated, the lithium precipitation phenomenon can be further avoided, the internal resistance of the battery can be furthest reduced, and the safety performance of the battery can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and particularly to a current collector, a pole piece, a battery cell, a battery, and an electrical device. Background Art

[0002] A current collector is a battery component used to collect current. Its main function is to collect the current generated by the electrode material so as to form a larger current and output the large current externally.

[0003] Among them, the electrode material serves as a carrier, enabling the current to flow between the current collector and the electrode during the operation of the battery. In the related art, generally, the electrode material is directly fixed on the surface of the current collector by coating.

[0004] However, in the coating method of the electrode material in the related art, the phenomenon of lithium deposition is likely to occur, and the battery energy efficiency is reduced. Summary of the Utility Model

[0005] In view of the above problems, the embodiments of the present application provide a current collector, a pole piece, a battery cell, a battery, and an electrical device, which helps to increase the contact area between the current collector near the pole ear and the dressing, thereby helping to reduce the contact resistance at the pole ear, alleviate the problem of easy lithium deposition at the pole ear of a high-rate fast-charging battery, further avoid the occurrence of lithium deposition phenomenon, minimize the internal resistance of the battery, and improve the safety performance of the battery.

[0006] To achieve the above object, the present application provides the following technical solutions:

[0007] In the first aspect of the embodiments of the present application, a current collector is provided. The current collector includes a main body portion, and the end of the main body portion is used to connect with the pole ear portion of the pole piece; opposite sides of the main body portion have coating surfaces, and each coating surface includes a plurality of coating regions distributed along the length direction of the current collector. At least one side of the coating regions is used for coating the dressing; and, along the length direction of the main body portion, the contact area between the coating region on the side close to the pole ear portion and the dressing is larger than the contact area between the coating region on the side far from the pole ear portion and the dressing.

[0008] In an implementable embodiment, the coating region includes a first coating region and two second coating regions. The two second coating regions are located at both ends of the current collector in the length direction, and the first coating region is located between the two second coating regions; the pole ear portion is close to the second coating region, and the contact area between the second coating region and the dressing is larger than the contact area between the first coating region and the dressing.

[0009] In an implementable embodiment, the coating surface on at least one side is provided with the convex portion; along the thickness direction of the main body portion, the contact area between the surface of the convex portion located in the second coating area and the dressing is larger than the contact area between the surface of the convex portion located in the first coating area and the dressing; wherein, the surface of the convex portion is perpendicular to the length direction of the current collector.

[0010] In an implementable embodiment, the ratio of the contact area between the convex portion distributed in the first coating area and the dressing in the thickness direction of the current collector to the projected area of the first coating area in the thickness direction of the current collector is 1.

[0011] In an implementable embodiment, a plurality of convex portions are provided on the coating surface on one side of the current collector, and the plurality of convex portions are arranged at intervals along the length direction of the current collector; a groove is formed between adjacent convex portions; wherein, the distance between the grooves located in the first coating area is L1, and the distance between the grooves located in the second coating area is L2, and L1 > L2.

[0012] In an implementable embodiment, the number of the grooves located in the first coating area is M, and the number of the grooves located in the second coating area is N, wherein, N > M, and N ≥ 2;

[0013] And / or, the number of the convex portions located in the second coating area is larger than the number of the convex portions located in the first coating area.

[0014] In an implementable embodiment, the thickness of the area where the convex portion is not provided on the surface of the current collector is D0, wherein, D0 ≥ 3 μm.

[0015] A second aspect of the embodiments of the present application provides a pole piece, which includes a pole ear portion, a current collector, and a dressing coated on the coating surface of the current collector; the pole ear portion is connected to the end of the current collector or at least part of the end of the current collector forms the pole ear portion.

[0016] In an implementable embodiment, in the length direction of the current collector, the coating amount of the dressing on the side close to the pole ear portion is more than the coating amount of the dressing on the non-pole ear portion side.

[0017] A third aspect of the embodiments of the present application provides an electric core, which includes a pole piece, and the pole piece includes a positive pole piece and a negative pole piece.

[0018] In an implementable embodiment, the thickness dimension of the current collector of the positive pole piece is D1, 3 μm ≤ D1 ≤ 30 μm; and / or, the thickness dimension of the current collector of the negative pole piece is D2, 3 μm ≤ D2 ≤ 25 μm.

[0019] In a fourth aspect of the embodiments of the present application, a battery is provided. The battery includes a housing and an electrode core, and the electrode core is disposed inside the housing.

[0020] In a fifth aspect of the embodiments of the present application, an electrical device is provided. The electrical device includes a battery.

[0021] The embodiments of the present application provide a current collector, a pole piece, an electrode core, a battery, and an electrical device. The current collector includes a main body portion. Along the length direction of the main body portion, the contact area between the coating area closer to the tab side and the dressing is larger than the contact area between the coating area farther from the tab side and the dressing. In this way, it helps to increase the contact area between the current collector near the tab and the dressing, thereby helping to reduce the contact resistance at the tab, alleviating the problem of easy lithium deposition at the tab of the high-rate fast-charging battery, further avoiding the occurrence of lithium deposition phenomenon, minimizing the internal resistance of the battery, and improving the safety performance of the battery. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 It is a top view of the electrode core provided by the embodiments of the present application;

[0024] Figure 2 It is a cross-sectional view of the pole piece provided by the embodiments of the present application;

[0025] Figure 3 It is a top view of the pole piece with a tab provided by the embodiments of the present application;

[0026] Figure 4 It is a schematic structural view of the current collector provided by the embodiments of the present application Figure 1 ;

[0027] Figure 5 It is a schematic structural view of the current collector provided by the embodiments of the present application Figure 2 。

[0028] Description of the Reference Numerals:

[0029] 100 - Current collector;

[0030] 110 - Main body portion; 120 - Protrusion portion; 121 - Convex surface of the protrusion portion

[0031] 130 - Coating area; 131 - First coating area; 132 - Second coating area;

[0032] 140 - Groove; 150 - Tab; 151 - Positive tab;

[0033] 152 - Negative tab;

[0034] 200 - Electrode; 210 - Coating; 300 - Battery cell. Detailed implementation manners

[0035] The current collector is a conductive material with a smooth surface, and the surface of the current collector is coated with electrode material. The electrode material serves as a carrier, enabling current to flow between the current collector and the electrode during the operation of the battery.

[0036] In the related art, the current collector includes multiple coating areas, and the electrode material is coated on the coating areas, and the coating amounts of the electrode material on the multiple coating areas are the same. However, for the current collector in the related art, due to problems such as different electron transport and electrolyte infiltration properties, it will lead to uneven current distribution, easy heat generation in the electrode, reduced battery energy efficiency or lithium plating phenomenon. Especially for large-size or long-size batteries, the impedance is large near the tab during high-rate charge and discharge, resulting in high heat generation and easy lithium plating, which easily leads to problems such as short circuit and cycle performance degradation.

[0037] To address the above technical problems, the embodiments of the present application provide a current collector, an electrode, a battery cell, a battery, and an electrical device. The current collector includes a main body portion. Along the length direction of the main body portion, the contact area between the coating area near the tab and the coating is larger than the contact area between the coating area far from the tab and the coating. In this way, it helps to increase the contact area between the current collector near the tab and the coating, thereby helping to reduce the contact resistance at the tab, alleviate the problem of easy lithium plating at the tab of the high-rate fast-charging battery, further avoid the lithium plating phenomenon, minimize the internal resistance of the battery, and improve the safety performance of the battery.

[0038] It should be noted that lithium plating generally refers to the phenomenon of dissolution, migration, and deposition of lithium metal caused by internal chemical reactions during the use or storage of lithium-ion batteries. For example, during the charge and discharge process of a lithium-ion battery, the lithium ions that should be embedded in the negative electrode do not enter the negative electrode and precipitate on the surface of the negative electrode, and this phenomenon is called lithium plating. This phenomenon may lead to a decline in battery performance and even pose safety problems. The reasons for lithium plating may include high temperature, overcharging, excessive number of cycles, etc. To prevent the occurrence of lithium plating, appropriate measures such as controlling the charging conditions and maintaining an appropriate working temperature need to be taken.

[0039] Among them, the occurrence of lithium plating will lead to a decline in the cycle performance of the battery, that is, after a certain number of charge and discharge cycles, the capacity of the battery will drop significantly, and this phenomenon is called "cycle performance degradation" or "capacity degradation".

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the accompanying drawings in the embodiments of this application. In the drawings, the same or similar reference numerals denote the same or similar components or components with the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of this application. The embodiments described below by referring to the drawings are exemplary and are intended to explain this application and should not be construed as a limitation of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts fall within the scope of protection of this application.

[0041] The embodiments of this application provide an electrical device, which includes a battery. The battery can be used as a power source to supply power to the electrical device. Among them, the type of the electrical device is not limited. Exemplarily, the electrical device can be a vehicle, a mobile phone, a tablet computer, an electric toy, a spacecraft, etc. This embodiment does not make any limitations in this regard.

[0042] In the embodiments of this application, with reference to Figure 1 and Figure 2 as shown, the battery includes a housing, a battery cell 300, and an electrolyte. The housing is used to accommodate the battery cell 300 and the electrolyte. The battery cell 300 includes electrode plates 200 and a separator. The electrode plates 200 include a positive electrode plate and a negative electrode plate. The battery mainly works by the movement of metal ions between the positive electrode plate and the negative electrode plate.

[0043] Among them, the electrode plates 200 include current collectors 100 and coatings 210 coated on the coated surfaces of the current collectors 100. Specifically, the electrode plates 200 include a positive electrode plate and a negative electrode plate. Among them, the positive electrode plate includes a positive current collector and a positive coating, and the positive coating is coated on the coated surface of the positive current collector; the negative electrode plate includes a negative current collector and a negative coating, and the negative coating is coated on the coated surface of the negative current collector.

[0044] Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the positive coating can be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, etc.; the material of the negative current collector can be copper, and the negative coating can be carbon or silicon, etc. This embodiment does not make any limitations in this regard.

[0045] In this embodiment, the materials of the positive current collector and the negative current collector are not limited. Exemplarily, the positive current collector can be aluminum foil; the material of the negative current collector can be copper foil. This embodiment does not make any limitations in this regard.

[0046] In this embodiment, the thickness dimension of the current collector of the positive electrode plate is not limited. Among them, with reference to Figure 4As shown, the thickness dimension D1 of the positive current collector can be between 3 μm and 30 μm. Exemplarily, the thickness D1 of the positive current collector can be set to 3 μm, 10 μm, 20 μm, 30 μm or any value between 3 μm and 30 μm according to actual needs. In this way, the thickness of the positive current collector can be ensured to be within an appropriate range to guarantee the structural strength of the positive current collector; and it helps to ensure the effective transmission of current between the positive and negative electrodes, avoiding uneven current distribution caused by too thin a thickness or an increase in internal resistance caused by too thick a thickness, and improving the safety performance of the battery.

[0047] In this embodiment, the thickness dimension of the current collector of the negative electrode sheet is not limited. Among them, the thickness dimension D2 of the negative current collector can be between 3 μm and 25 μm. Exemplarily, the thickness dimension D2 of the negative current collector can be set to 3 μm, 10 μm, 20 μm, 25 μm or any value between 3 μm and 30 μm according to actual needs. In this way, the thickness of the negative current collector can be ensured to be within an appropriate range to guarantee the structural strength of the negative current collector, and it also helps to improve the flexibility of the negative current collector, making it not easy to break, and can also appropriately increase the areal density of the active material, thereby increasing the energy density, optimizing the performance of the battery, and improving the cycle stability, capacity retention rate and safety of the battery.

[0048] It should be noted that the liquid injection holes of the battery are generally at both ends, and when injecting liquid, it is injected from both ends. For large-sized or long-sized batteries, the electrolyte in the middle part of the battery is insufficient, or if the thickness of the electrode sheet 200 is too thick, the electrolyte in the middle part of the battery is difficult to infiltrate, resulting in uneven distribution of the electrolyte. Insufficient electrolyte in the middle part will cause lithium plating phenomenon.

[0049] In addition, in this embodiment, referring to Figure 1 and Figure 2 As shown, the electrode sheet further includes an electrode tab 150. Exemplarily, the electrode tab 150 can include one, such as a positive electrode tab or a negative electrode tab; or, the electrode tab 150 includes two, such as a positive electrode tab and a negative electrode tab.

[0050] Among them, the electrode tab 150 can be connected to the end of the current collector 100. Or, at least part of the end of the current collector 100 forms the electrode tab 150. This embodiment does not limit this.

[0051] In the embodiments of the present application, the ear part 150 mainly includes a positive electrode ear 151 and a negative electrode ear 152 as an example for illustration. The positive electrode ear 151 and the negative electrode ear 152 are located at both ends of the electrode sheet 200. When the current flows from the positive electrode ear 151 to the negative electrode ear 152, since the width of the ear is smaller than that of the electrode sheet 200, electrons will accumulate around the ear. Some electrons cannot flow smoothly from the positive electrode ear 151 to the negative electrode ear 152, and electrons are prone to blockage. The current density distribution in a local area of the electrode sheet 200 is uneven. Especially in the ear part, there will be a problem of excessive local current density and lithium deposition in the ear part.

[0052] Exemplarily, the ear part 150 can be referred to Figure 1 , Figure 2 and Figure 3 as shown in Region C in

[0053] Therefore, in this embodiment, as shown in Figure 3 , it is defined that the coating amount of the coating material 210 on the side close to the ear part 150 is more than that on the side other than the ear part. In this way, on the one hand, it helps to reduce the amount of the coating material 210 in the middle part of the electrode sheet 200, thereby reducing the infiltration requirement, and thus beneficial to avoiding the problem of lithium precipitation caused by insufficient electrolyte in the middle part; on the other hand, increasing the coating amount of the coating material 210 close to the ear part helps to increase the contact area between the current collector 100 and the coating material 210, effectively reduce the contact internal resistance of the current collector 100, and effectively relieve the problem of lithium precipitation in the ear part caused by the resistance of the ear part being greater than that of other regions; on the third hand, increasing the coating amount of the coating material 210 close to the ear part increases the number of carriers, so that lithium ions from the positive electrode to the negative electrode can have more carriers to form lithium carbide compounds, further ensuring that lithium precipitation will not occur.

[0054] It should be noted that the coating amount of the coating area 130 is not limited, and can be specifically set according to actual needs. This embodiment does not limit this.

[0055] Next, the structure of the current collector provided in the embodiments of the present application will be described in detail.

[0056] Referring to Figure 4 and Figure 5 shown, the current collector 100 includes a main body part 110. The end of the main body part 110 is connected to the ear part 150 or at least part of the main body part 110 forms the ear part 150.

[0057] The opposite sides of the main body part 110 have coating surfaces. The coating surfaces include a plurality of coating areas 130 distributed along the length direction of the current collector 100. At least one side of the coating areas 130 is used for coating the coating material.

[0058] It should be noted that the number of coating areas 130 is not limited and can be specifically set according to actual needs. It can be understood that the number of coating areas 130 includes at least two. Exemplarily, the number of coating areas 130 can be two, three, or more. In this way, it can ensure to avoid the problem of uneven current distribution caused by different electron transport and electrolyte wettability in different coating areas 130, thereby avoiding the phenomenon of lithium deposition, reducing the internal resistance of the battery, and improving the safety performance of the battery.

[0059] In the embodiment of the present application, along the length direction of the main body portion 110, the contact area between the coating area 130 closer to the tab portion 150 and the dressing 210 is larger than the contact area between the coating area 130 farther from the tab portion and the dressing 210.

[0060] It can be understood that in this direction, the contact area between the coating area 130 closer to the tab portion 150 and the dressing 210 is larger, so as to effectively reduce the contact resistance near the tab portion 150, and further effectively alleviate the problem of lithium deposition at the tab portion due to the resistance of the tab portion 150 being greater than that of other parts, minimize the internal resistance of the battery, and improve the safety performance of the battery; at the same time, since the internal resistance of the battery using the above current collector is smaller, it is more conducive to the battery for high-rate charge and discharge.

[0061] In an implementable embodiment, referring to Figure 4 and Figure 5 as shown, the coating area 130 may include a first coating area 131 and two second coating areas 132. The two second coating areas 132 are located at both ends of the length direction of the current collector 100, and the first coating area 131 is located between the two second coating areas 132.

[0062] Exemplarily, the first coating area 131 is located in the middle part of the electrode sheet 200, and the two second coating areas 132 are located at both ends of the electrode sheet 200, that is, the two second coating areas 132 are located at positions close to the tab portion. Exemplarily, the first coating area 131 may refer to the area A shown in Figure 4 and Figure 5 , and the second coating area 132 may refer to the area B shown in Figure 4 and Figure 5 .

[0063] Among them, the tab portion 150 is close to the second coating area 132 at both ends. The contact area between the second coating area 132 and the dressing 210 is larger than the contact area between the first coating area 131 and the dressing 210. In this way, the contact area between the second coating area 132 and the dressing 210 is effectively increased, the contact resistance of the tab portion 150 is reduced, and the problem of lithium deposition at the tab portion due to the resistance of the tab portion 150 being greater than that of other parts is effectively alleviated.

[0064] In an implementable embodiment, the coating surface on at least one side may be provided with a convex portion 120; along the thickness direction of the main body portion 110, the contact area between the convex surface 121 of the convex portion located in the second coating area 132 and the dressing 210 is larger than the contact area between the convex surface 121 of the convex portion in the first coating area 131 and the dressing 210.

[0065] It should be noted that in this embodiment, the convex surface 121 of the convex portion is a surface perpendicular to the length direction of the current collector 100. Exemplarily, the convex surface 121 of the convex portion may refer to Figure 5 as shown.

[0066] In this embodiment, the position of the convex portion 120 is not limited. Exemplarily, the convex portion 120 may be provided only on one coating surface of the main body portion 110; or, the convex portion 120 may be provided only on the other coating surface of the main body portion 110; or, the convex portion 120 may be provided on the coating surfaces on opposite sides of the main body portion 110 at the same time. This embodiment does not make any limitation on this.

[0067] In this embodiment, the shape of the convex portion 120 is not limited. Exemplarily, the convex portion 120 may be a strip structure; or, the convex portion 120 may be a circular structure; or, the convex portion 120 may be other shapes. This embodiment does not make any limitation on this. In addition, the number and size of the convex portions 120 are also not limited, and can be specifically set according to actual needs.

[0068] In this way, by providing the convex portion 120, the bonding strength between the current collector 100 and the electrode material can be effectively improved, the contact area between the current collector 100 and the electrode material can be enhanced, thereby contributing to improving the electron conduction ability between the current collector 100 and the electrode material, and effectively reducing the contact internal resistance of the current collector 100.

[0069] In an implementable embodiment, referring to Figure 5 as shown, the ratio of the contact area between the convex portion 120 distributed in the first coating area 131 and the dressing 210 in the thickness direction of the current collector 100 to the projected area of the first coating area 131 in the thickness direction of the current collector can be 1.

[0070] In this embodiment, referring to Figure 5 as shown, no groove is provided on the first coating area 131. It can be understood that the first coating area 131 is completely covered by the convex portion 120. In this way, it is beneficial to simplify the processing process on the first coating area 131, reduce the processing cost, improve the processing efficiency, and at the same time, it can also meet the requirement of reducing the amount of the dressing 210 on the first coating area 131, thereby ensuring the reduction of the infiltration requirement.

[0071] In an implementable embodiment, referring to Figure 4 andFigure 5 As shown, a plurality of protruding portions 120 may be provided on the coating surface on one side of the current collector 100, and the plurality of protruding portions 120 are arranged at intervals along the length direction of the current collector 100; a groove 140 is formed between adjacent protruding portions 120.

[0072] Among them, with reference to Figure 4 As shown, the spacing of the grooves 140 located in the first coating area 131 is L1, and the spacing of the grooves 140 located in the second coating area 132 is L2, and L1 > L2. Exemplarily, the length of the protruding portion 120 located in the first coating area 131 is a, and the length of the protruding portion 120 located in the second coating area 132 is b.

[0073] In this embodiment, the number of the protruding portions 120 in the first coating area 131 and the second coating area 132 is not limited. Exemplarily, if there are four protruding portions 120 in the first coating area 131, and a groove 140 is formed between adjacent protruding portions 120, that is, there are three grooves 140 in the first coating area 131.

[0074] In this embodiment, the difference between different coating areas 130 is mainly described from the interval distance (density) of the grooves 140. By defining L1 > L2, that is, the distribution of the grooves 140 located in the first coating area 131 is sparser, and the distribution of the grooves 140 located in the second coating area 132 is denser.

[0075] In this way, the number of the protruding portions 120 in different coating areas 130 can be directly observed, saving the judgment time. At the same time, it can also meet the requirement of reducing the amount of the dressing 210 in the first coating area 131, thereby ensuring the reduction of the infiltration requirement. Moreover, it can effectively alleviate the problem of lithium deposition at the current collector ear due to the resistance of the current collector ear being greater than that of other areas.

[0076] In an implementable embodiment, with reference to Figure 4 and Figure 5 As shown, the number of the grooves 140 located in the first coating area 131 may be M, and the number of the grooves 140 located in the second coating area 132 may be N, where N > M and N ≥ 2. Exemplarily, N may be 2, 3, 5 or any value greater than 2, and M may be any value greater than N. It should be noted that N and M cannot be infinitely large, and can be specifically set according to actual needs. In addition, defining N ≥ 2 is beneficial to ensuring the distinction between different coating areas 130.

[0077] In this way, the number of the protruding portions 120 in different coating areas 130 can also be directly observed, saving the judgment time. At the same time, it can also meet the requirement of reducing the amount of the dressing 210 in the first coating area 131, thereby ensuring the reduction of the infiltration requirement. Moreover, it can effectively alleviate the problem of lithium deposition at the current collector ear due to the resistance of the current collector ear being greater than that of other areas.

[0078] Alternatively, the number of the protrusions 120 located on the second coating area 132 is larger than the number of the protrusions 120 located on the first coating area 131. In this way, the protrusions 120 on the second coating area 132 are more dense, which helps to increase the contact area with the dressing 210 on the second coating area 132.

[0079] In an implementable embodiment, referring to Figure 4 As shown, the thickness of the area where no protrusion 120 is provided on the surface of the current collector 100 may be D0, where D0≥3 μm. Exemplarily, D0 may be 3 μm, 5 μm, 7 μm or any value not less than 3 μm. Of course, the thickness of the area where no protrusion 120 is provided cannot be infinitely large and can be specifically set according to actual needs.

[0080] It can be understood that the thickness of the area where no protrusion 120 is provided on the surface of the current collector 100 can also be referred to as the residual thickness of the current collector 100, which helps to ensure the structural strength of the current collector 100 and the current-carrying capacity of the electrode sheet 200.

[0081] In an implementable embodiment, protrusions 120 may be provided on the coating surfaces on both sides of the main body portion 110. Exemplarily, the number of the protrusions 120 on the coating surfaces on both sides of the main body portion 110 may be the same or different, and this embodiment does not limit this; Exemplarily, the arrangement modes of the protrusions 120 on the coating surfaces on both sides of the main body portion 110 may be the same or different, and this embodiment does not limit this; Exemplarily, the protrusions 120 on the coating surfaces on both sides of the main body portion 110 may be symmetrically distributed or staggered, and this embodiment does not limit this. It can be specifically set according to actual needs.

[0082] The embodiment of the present application provides a current collector, an electrode sheet, an electric core, a battery and an electrical device. The current collector includes a main body portion. Along the length direction of the main body portion, the contact area between the coating area close to the tab portion and the dressing is larger than the contact area between the coating area far from the tab portion and the dressing. In this way, it helps to increase the contact area between the current collector near the tab and the dressing, thereby helping to solve the problem that lithium deposition is likely to occur at the tab of a high-rate fast-charging battery, further avoiding the occurrence of lithium deposition phenomenon, minimizing the internal resistance of the battery, and improving the safety performance of the battery.

[0083] In the description of the present application, it should be noted that unless otherwise clearly specified or limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, or indirectly connected through an intermediate medium, and can be the connection inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0084] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application.

[0085] The terms "first", "second", "third", "fourth", etc. (if any) in the description, claims, and drawings of the present application are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here.

[0086] In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A current collector, characterized in that, The current collector includes: A main body portion (110), and the end of the main body portion (110) is used to connect with the tab portion (150) of the electrode plate or at least partially form the tab portion (150); The opposite sides of the main body portion (110) have coating surfaces, and the coating surfaces include a plurality of coating areas (130) distributed along the length direction of the current collector, and at least one side of the coating areas (130) is used for coating the dressing; Moreover, along the length direction of the main body portion (110), the contact area between the coating area (130) on the side close to the tab portion (150) and the dressing (210) is larger than the contact area between the coating area (130) on the side far from the tab portion (150) and the dressing (210).

2. The current collector according to claim 1, characterized in that, The coating area (130) includes a first coating area (131) and two second coating areas (132), the two second coating areas (132) are located at both ends of the current collector in the length direction, the first coating area (131) is located between the two second coating areas (132), and the tab portion (150) is close to the second coating area (132); The contact area between the second coating area (132) and the dressing (210) is larger than the contact area between the first coating area (131) and the dressing (210).

3. The current collector according to claim 2, characterized in that, At least one side of the coating surface is provided with a protrusion (120); Along the thickness direction of the main body portion (110), the contact area between the convex surface (121) of the protrusion located in the second coating area (132) and the dressing (210) is larger than the contact area between the convex surface (121) of the protrusion in the first coating area (131) and the dressing (210); Wherein, the convex surface (121) of the protrusion is a surface perpendicular to the length direction of the current collector.

4. The current collector according to claim 3, wherein The ratio of the contact area between the protrusion (120) distributed in the first coating area (131) and the dressing (210) in the thickness direction of the current collector to the projected area of the first coating area (131) in the thickness direction of the current collector is 1.

5. The current collector according to claim 3, wherein A plurality of protrusions (120) are provided on the coating surface of one side of the current collector, and the plurality of protrusions (120) are arranged at intervals along the length direction of the current collector; grooves are formed between adjacent protrusions (120); Wherein, the distance between the grooves located in the first coating area (131) is L1, the distance between the grooves located in the second coating area (132) is L2, and L1 > L2.

6. The current collector according to claim 5, wherein The number of grooves located in the first coating area (131) is M, the number of grooves located in the second coating area (132) is N, wherein, N > M, N ≥ 2; And / or, the number of protrusions (120) located in the second coating area (132) is more than the number of protrusions (120) located in the first coating area (131).

7. The current collector according to any one of claims 3-6, characterized in that, The thickness of the area where the protrusion (120) is not provided on the surface of the current collector is D0, wherein, D0 ≥ 3 μm.

8. A pole piece, characterized in that, The electrode includes an electrode tab, a current collector as described in any one of claims 1-7, and a dressing coated on the coated surface of the current collector; the electrode tab is connected to the end of the current collector or at least part of the end of the current collector forms the electrode tab.

9. The pole piece according to claim 8, wherein In the length direction of the current collector, the coating amount of the dressing (210) on the side close to the electrode tab (150) is more than that of the dressing (210) on the non-electrode tab side.

10. A battery cell, characterized in that, The battery cell includes an electrode as described in claim 8, and the electrode includes a positive electrode and a negative electrode.

11. The battery cell according to claim 10, wherein, The thickness dimension of the current collector of the positive electrode is D1, 3μm ≤ D1 ≤ 30μm; and / or, the thickness dimension of the current collector of the negative electrode is D2, 3μm ≤ D2 ≤ 25μm.

12. A battery, characterized in that, The battery includes a housing and a battery cell as described in claim 10, and the battery cell is disposed inside the housing.

13. An electrical device, characterized in that, The electrical device includes a battery as described in claim 12.

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