Current collector, pole piece and battery

Abstract

The utility model discloses a current collector, a pole piece and a battery. The current collector comprises a main body part, a tab part and a lug part, the tab part is connected to the main body part, and the thickness of the tab part is greater than that of the main body part; the protruding part is arranged on at least one face, in the thickness direction of the protruding part, of the main body part and protrudes relative to the main body part. According to the current collector, the pole piece and the battery disclosed by the utility model, the possibility that the piece body for preparing the current collector is damaged in a rolling process can be reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field especially relates to current collector, pole piece and battery. BACKGROUND

[0002] The pole piece of prior art includes current collector and active material layer coated on the current collector, the area of the current collector not coated as tab. The tab is directly welded to the cover plate or the tab is welded to the cover plate through the connecting sheet, and the tab is used as the current path between the electrode and the cover plate. If the overcurrent capacity of the tab is to be improved, the thickness of the current collector needs to be increased, and the battery cell is stacked or wound by the negative pole piece - diaphragm - positive pole piece structure. The increase of the thickness of the current collector leads to the increase of the thickness of the pole piece, thereby reducing the energy density of the battery cell and increasing the cost.

[0003] The technical scheme provides a kind of pole piece, including current collector, current collector includes tab area and coating active material layer's coating area, wherein the thickness of tab area is greater than the thickness of coating active material layer's coating area, to increase the overcurrent capacity of tab area, while the thickness size of pole piece will not increase, so as to guarantee the energy density of battery cell. However, it is found that the sheet body of the above-mentioned current collector is easy to be damaged during winding in the processing process. SUMMARY

[0004] The utility model aims at at least one of the technical problems existing in prior art. To this end, the utility model provides a kind of current collector, pole piece and battery, which can reduce the possibility of damage of the sheet body of the prepared current collector during winding.

[0005] The utility model provides a kind of current collector, including main part, tab part and protruding part;

[0006] The tab part is connected to the main part, and the thickness of the tab part is greater than the thickness of the main part;

[0007] The protruding part is arranged on at least one side of the main part along the thickness direction of the main part and protrudes relative to the main part.

[0008] In some embodiments, along the thickness direction of the main part, the height difference between the end surface of the protruding part away from the main part and the end surface of the tab part on the same side is H, and the height difference H satisfies 0

[0009] In some embodiments, the protruding part extends along a first direction, and the first direction intersects the width direction of the main part.

[0010] In some embodiments, the first direction is perpendicular to the width direction of the main part.

[0011] In some embodiments, multiple protrusions are provided, and the multiple protrusions are spaced apart along the width direction of the main body.

[0012] In some embodiments, multiple protrusions are provided, and the multiple protrusions are spaced apart along the length direction of the main body.

[0013] In some embodiments, along the thickness direction of the main body, both end faces of the main body are lower than the corresponding end faces of the tabs; or,

[0014] Along the thickness direction of the main body, one end face of the main body is lower than one end face of the electrode tab, and the other end face of the main body is at the same height as the other end face of the electrode tab.

[0015] In some embodiments, the thickness of the tab portion is at least 1 μm greater than the thickness of the main body portion.

[0016] In some embodiments, the thickness of the main body is 4μm-8μm, and the thickness of the tab is 5μm-20μm.

[0017] In some embodiments, the width of the protrusion is 0.1mm-1mm.

[0018] In some embodiments, the interval between adjacent protrusions along the width direction of the main body is 1mm-10mm.

[0019] This utility model also proposes an electrode sheet, comprising:

[0020] The current collector described in the above embodiments;

[0021] An active material layer is provided, wherein the main body and the protrusion constitute a carrier, and the active material layer covers the two opposite surfaces of the carrier along its own thickness direction.

[0022] This invention also proposes a battery, including the electrode sheets described in the above embodiments.

[0023] The current collector, electrode, and battery according to embodiments of this utility model have at least the following beneficial effects: By making the thickness of the main body relatively thin and the thickness of the tab relatively thick, the current-carrying capacity of the tab can be improved without increasing the overall thickness of the electrode, thereby helping to increase the energy density of the battery. By providing a protrusion protruding from the main body, the contact area between the active material layer and the current collector can be increased, thereby improving the peeling force between the active material layer and the current collector. This ensures the stability and reliability of the battery during assembly, operation, and use. By providing the protrusion on at least one side of the main body along its own thickness direction and protruding relatively, the protrusion can support the main body of adjacent layers during the winding process of the current collector sheet, thereby largely avoiding misalignment problems during the winding process and also preventing deformation and damage of the main body along the thickness direction.

[0024] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0026] Figure 1 This is a schematic diagram of the first structure of the current collector according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the second structure of the current collector according to an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the electrode structure according to an embodiment of the present invention.

[0029] Figure label:

[0030] 10. Main body; 20. Electrode; 30. Protrusion; 100. Current collector; 200. Active material layer. Detailed Implementation

[0031] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0032] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0033] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0034] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0035] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0036] In related technologies, the electrode includes a current collector and an active material layer coated on the current collector. The current collector includes a tab and a main body covering the current collector. The electrode core is formed by winding or stacking the electrode in a negative electrode-separator-positive electrode structure. The negative and positive tabs are welded to a cover plate, the electrode core is placed in the battery casing, and electrolyte is injected to form a battery cell. The active material layer releases and receives ions, and electrons are output to the outside of the battery cell through the active material layer-main body-tab-cover plate, or electrons from the outside of the battery cell are input to the inside of the battery cell through the cover plate-tab-main body-active material layer, forming the charging and discharging process. During the charging and discharging process, the current converges at the tab, and the large current passing through the tab generates a large amount of heat, raising the temperature of the tab and the coating near the tab.

[0037] To improve the current carrying capacity of the tabs, the thickness of the current collector needs to be increased. However, the battery cell is formed by stacking or winding a negative electrode, separator, and positive electrode structure. Increasing the current collector thickness leads to increasing the electrode thickness, which in turn reduces the energy density of the battery cell and increases the cost.

[0038] One technical solution provides an electrode sheet including a tab region and a coating region coated with an active material layer. The thickness of the tab region is greater than that of the coating region, thereby increasing the current carrying capacity of the tab region while maintaining the electrode sheet's overall thickness, thus ensuring the cell's energy density. However, due to the inconsistent thickness of the tab region and the coating region, during winding, the winding diameter of the relatively thicker tab region increases at a faster rate. Once the winding diameter reaches a certain point, misalignment along the width direction can easily occur between adjacent layers. This misalignment can cause the coating region in the middle to be compressed and deformed. Furthermore, the inconsistent thickness of the tab region and the coating region also means that the tab region, with its faster winding diameter increase, bears greater tension, making it more prone to breakage.

[0039] Please refer to the following for details. Figure 1 and Figure 2 The present application provides a current collector, including a main body 10, an electrode tab 20, and a protrusion 30.

[0040] The main body 10 is used for conducting electricity and collecting current.

[0041] The tab 20 can conduct current from the electrode assembly. For example, the tab 20 can be directly soldered to the cover plate or soldered to the cover plate via a connecting tab, thereby serving as a current path between the electrode assembly and the cover plate.

[0042] The tab 20 is connected to the main body 10. The specific connection position is not limited. In some embodiments, along the width direction of the main body 10, the tab 20 may be distributed at one end of the main body 10 or at opposite ends of the main body 10.

[0043] The thickness of the tab portion 20 is greater than the thickness of the main body portion 10. It is understandable that by making the main body portion 10 relatively thin and the tab portion 20 relatively thick, the current carrying capacity of the tab portion 20 can be improved without increasing the overall thickness of the electrode, thereby helping to increase the energy density of the battery.

[0044] The protrusion 30 is provided on at least one side of the main body 10 along its own thickness direction and protrudes relative to the main body 10. That is, the protrusion 30 can be provided on one side or two opposite sides of the main body 10 along its own thickness direction. The protrusion 30 can work with the main body 10 to achieve the functions of conducting electricity and collecting current. During the winding process of the current collector 100 layer by layer, the protruding protrusion 30 can support the main body 10 of the adjacent layers.

[0045] It should be noted that the main body portion 10 and the convex portion 30 are directly formed on the sheet. The current collector is obtained by dividing the sheet into pieces along the length direction and then cutting the tab portions, resulting in a current collector having the main body portion 10, the tab portions 20, and the convex portion 30.

[0046] It can be understood that, please refer to Figure 3 , the active material layer 200 covers the main body portion 10 and the convex portion 30 of the current collector 100. By providing the convex portion 30 protruding from the main body portion 10, the contact area between the active material layer 200 and the current collector 100 can be increased, thereby improving the peeling force between the active material layer 200 and the current collector 100. Ensure the stability and reliability of the battery during assembly, operation, and use.

[0047] In the above embodiment, by providing the convex portion 30 protruding from the main body portion 10, the contact area between the active material layer 200 and the current collector 100 can be increased, thereby improving the peeling force between the active material layer 200 and the current collector 100. Ensure the stability and reliability of the battery during assembly, operation, and use. By providing a relatively protruding convex portion on at least one side of the main body portion along its thickness direction. During the winding process of the current collector 100 layer by layer, the convex portion 30 can support the main body portion 10 of the adjacent layer, thereby largely avoiding the misalignment problem during the winding process, and also preventing the deformation of the main body portion 10 along the thickness direction.

[0048] In some embodiments, along the thickness direction of the main body portion, the height difference between the end face of the convex portion facing away from the main body portion and the end face of the tab portion on the same side is H, and the height difference H satisfies 0 < H ≤ 1 μm. This further reduces the possibility of misalignment problems occurring during the winding process of the current collector.

[0049] Furthermore, in some embodiments, along the thickness direction of the main body portion 10, the end face of the convex portion 30 facing away from the main body portion 10 is flush with the end face of the tab portion 20 on the same side. In this way, during the winding process of the current collector 100 layer by layer, the convex portion 30 can support the main body portion 10 of the adjacent layer, making the layer thickness of the current collector 100 as a whole the same along the width direction of the main body portion 10.

[0050] It can be understood that multiple convex portions 30 can be provided, and the multiple convex portions 30 extend along the width direction of the main body portion 10.

[0051] In order to improve the anti-fracture performance. In some embodiments, the extending direction of the convex portion 30 intersects with the width direction of the main body portion 10. It can be understood that the winding direction is the length direction of the current collector 100. During winding, the convex portion 30 and the main body portion 10 jointly bear the tension, reducing the stress borne by the main body portion 10 during the winding process, thereby greatly reducing the possibility of the current collector 100 breaking during winding.

[0052] In some embodiments, the extension direction of the protrusion is perpendicular to the width direction of the main body 10. That is, the extension direction of the protrusion is parallel to the length direction of the current collector 100. Thus, during winding, the direction of tension is the same as the extension direction of the protrusion 30, which allows the protrusion 30 to better share the stress with the main body 10 under tension.

[0053] It is understood that the number of protrusions 30 is not limited and can be adaptively adjusted according to the mechanical and electrical properties of the current collector 100 material. In some embodiments, multiple protrusions 30 are provided, and the multiple protrusions 30 are spaced apart along the width direction of the main body 10. The multiple spaced protrusions 30 can better distribute the winding tension along the width direction of the main body 10 and reduce stress concentration. In other embodiments, the multiple protrusions are spaced apart along the length direction of the main body.

[0054] In some embodiments, the spacing between the plurality of protrusions 30 is equal. The spacing between the first protrusion 30 in the width direction of the main body 10 and the adjacent tab 20 is equal to the spacing between the first protrusion 30 and the second protrusion 30. The spacing between the last protrusion 30 in the width direction of the main body 10 and the adjacent tab 20 is equal to the spacing between the last protrusion 30 and the penultimate protrusion 30. This further reduces the problem of stress concentration.

[0055] It is understandable that the relative positions of the main body 10 and the tab 20 along the thickness direction of the main body 10 are not limited.

[0056] In some embodiments, along the thickness direction of the main body 10, one end face of the main body 10 is lower than one end face of the tab 20, and the other end face of the main body 10 is at the same height as the other end face of the tab 20. The protrusions 30 may be distributed on the end face of the main body 10 that is lower than the corresponding tab 20.

[0057] In some embodiments, along the thickness direction of the main body 10, both end faces of the main body 10 are lower than the corresponding end faces of the tabs 20. That is, the end face of one end of the main body 10 along the thickness direction is lower than the end face of one end of the tab 20, and the end face of the other end of the main body 10 along the thickness direction is lower than the end face of the other end of the tab 20. Protrusions 30 are provided on both end faces of the main body 10 along its own thickness direction. This results in a more uniform force distribution along the thickness direction, which helps reduce the occurrence of damage caused by uneven force distribution along the thickness direction.

[0058] Furthermore, in some embodiments, both end faces of the main body 10 are lower than the corresponding end faces of the tab 20, and the difference between the two end faces of the main body 10 and the corresponding end faces of the tab 20 is equal.

[0059] The specific value by which the thickness of the tab 20 is greater than the thickness of the main body 10 is not limited, and can be adaptively adjusted according to the mechanical and electrical properties of the current collector 100 material. In some embodiments, the thickness of the tab 20 is at least 1 μm greater than the thickness of the main body 10.

[0060] In some embodiments, the thickness of the main body 10 is 4μm-8μm, and the thickness of the tab 20 is 5μm-20μm. It is understood that the thickness of the main body 10 is 4μm, 5μm, 6μm, 7μm or 8μm, and the thickness of the tab 20 is 5μm, 10μm, 15μm or 20μm.

[0061] It is understood that the specific shape of the protrusion 30 is not limited. In some embodiments, the protrusion 30 is one of a straight line, a wavy line, a broken line, or a curve.

[0062] It is understood that the width of the protrusion 30 is not limited and can be adaptively adjusted according to the mechanical and electrical properties of the material. In some embodiments, the width of the protrusion 30 is 0.1mm-1mm. It is understood that when the protrusion 30 is a straight line, its width dimension is the same as the width dimension of the main body 10. When the protrusion 30 is a wavy line or a curve, its width dimension is the width dimension of the cross-section of the wavy line.

[0063] Similarly, the spacing between adjacent protrusions 30 is not limited. In some embodiments, the spacing between adjacent protrusions 30 along the width direction of the main body 10 is 1mm-10mm.

[0064] In some embodiments, the current collector 100 is a metal foil. The material of the current collector 100 includes, but is not limited to, aluminum, copper, nickel, titanium, silver, nickel-copper alloy, aluminum-zirconium alloy, etc.

[0065] Please refer to Figure 3 This application also provides an electrode sheet, which includes a current collector 100 and an active material layer 200.

[0066] The active material layer 200 is used for electrochemical reactions, and the specific materials in the active material layer 200, such as active materials, binders, conductive agents and solvents, can be adapted according to the type of electrode and the type of battery in which the electrode will be applied, without any particular limitation.

[0067] For example, when the electrode of this application is applied to a lithium battery, and the electrode is a positive electrode, the active material in the active material layer 200 can be a nickel-cobalt-manganese compound or lithium iron phosphate, etc.; while when the electrode is a negative electrode, the active material layer 200 can be graphite, etc. Furthermore, when the electrode of this application is applied to an aqueous battery, and the electrode is an aqueous positive electrode, the active material layer 200 contains lithium iron phosphate positive electrode active material, an aqueous binder, and water as a solvent.

[0068] The main body 10 and the protrusion 30 constitute a carrier, and the active material layer 200 covers the two opposite surfaces of the carrier along its own thickness direction.

[0069] In some embodiments, the thickness of the single-sided active material layer 200 is 20μm-200μm.

[0070] This application provides embodiments and comparative examples:

[0071] Example:

[0072] One current collector is made of aluminum foil, with a single active material layer thickness of 12μm, a tab thickness of 20μm, and a combined thickness of 8μm for the protrusions on both sides. Another current collector is made of copper foil, with a single active material layer thickness of 6μm, a tab thickness of 15μm, and a combined thickness of 9μm for the protrusions on both sides. Lithium iron phosphate positive electrode slurry is coated on the aluminum foil, with a total coating thickness of 150μm. Graphite negative electrode slurry is coated on the copper foil, with a coating thickness of 107μm. The electrodes are stacked in a negative electrode-separator-positive electrode structure to form the core. The core is placed in an aluminum shell, which is then welded to a cover plate. Electrolyte is injected into the aluminum shell to form the battery cell. This battery cell has a thickness of 16mm, a length of 510mm, and a width of 120mm. Its capacity is 130Ah.

[0073] Example for comparison:

[0074] One current collector is a uniformly thick aluminum foil, 12 μm thick. Another current collector is a uniformly thick copper foil, 6 μm thick. Lithium iron phosphate positive electrode slurry is coated onto the aluminum foil, with a total coating thickness of 150 μm. Graphite negative electrode slurry is coated onto the copper foil, with a coating thickness of 107 μm. The electrodes are stacked in a negative electrode-separator-positive electrode structure to form the electrode core. The electrode core is placed in an aluminum shell, which is then welded to a cover plate. Electrolyte is injected into the aluminum shell to form the battery cell. This battery cell has a thickness of 16 mm, a length of 510 mm, and a width of 120 mm. Its capacity is 130 Ah.

[0075] In both the example and control examples, the battery cells were charged with a 520A current for 10 minutes starting from 10% SOC at 25°C, and the highest temperature at different locations of the battery cells was measured.

[0076]

[0077] In the example, the electrode temperature and the coating temperature near the electrode were significantly lower than those in the control example.

[0078] This application also provides a battery, including electrode sheets. This application does not limit the specific type of battery, which can be a lithium-ion battery, sodium-ion battery, potassium-ion battery, or air battery, etc. To achieve environmentally friendly, pollution-free, and low-cost effects, the battery can be an aqueous battery. Here, "battery" refers to a battery assembly, battery module, or battery pack.

[0079] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A current collector, characterized in that, The current collector includes a main body, an electrode tab, and a protrusion. The electrode tab is connected to the main body, and the thickness of the electrode tab is greater than the thickness of the main body; The protrusion is located on at least one side of the main body along its own thickness direction and protrudes relative to the main body.

2. The current collector according to claim 1, characterized in that, Along the thickness direction of the main body, the height difference H between the end face of the protrusion away from the main body and the end face of the electrode tab on the same side is 0. The height difference H satisfies 0. <H≤1μm。 3. The current collector according to claim 1, characterized in that, The extension direction of the protrusion intersects the width direction of the main body.

4. The current collector according to claim 3, characterized in that, The extension direction of the protrusion is perpendicular to the width direction of the main body.

5. The current collector according to claim 3, characterized in that, The protrusions are provided in multiple portions, and the multiple protrusions are spaced apart along the width direction of the main body; and / or; The protrusions are provided in multiple portions, and the multiple protrusions are spaced apart along the length direction of the main body.

6. The current collector according to claim 1, characterized in that, Along the thickness direction of the main body, both end faces of the main body are lower than the corresponding end faces of the tabs; or, Along the thickness direction of the main body, one end face of the main body is lower than one end face of the electrode tab, and the other end face of the main body is at the same height as the other end face of the electrode tab.

7. The current collector according to any one of claims 1-4, characterized in that, The thickness of the tab portion is at least 1 μm greater than the thickness of the main body portion; and / or, The thickness of the main body is 4μm-8μm, and the thickness of the tab is 5μm-20μm.

8. The current collector according to any one of claims 1-4, characterized in that, The width of the protrusion is 0.1mm-1mm; and / or, The interval between adjacent protrusions along the width direction of the main body is 1mm-10mm.

9. An electrode sheet, characterized in that, include: The current collector according to any one of claims 1-8; An active material layer is provided, wherein the main body and the protrusion constitute a carrier, and the active material layer covers the two opposite surfaces of the carrier along its own thickness direction.

10. A battery, characterized in that, Includes the electrode sheet as described in claim 9.

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