Electrode plate and battery

Abstract

The invention discloses an electrode plate and a battery, and relates to the technical field of batteries. The electrode plate comprises a composite laminated layer and a current collector, the composite laminated layer comprises a first electrode film and a second electrode film, at least one side of the first electrode film is provided with concave-convex lines, and the second electrode film is compounded on the side, provided with the concave-convex lines, of the first electrode film; and one side, corresponding to the first electrode film and far away from the second electrode film, of the composite laminated layer is compounded on the current collector. The electrode plate provided by the invention has the characteristic of convenience in electrolyte infiltration.

Description

[0001] This application is a divisional application of the invention patent application filed on November 2, 2022, with the invention name “A method for preparing an electrode sheet, an electrode sheet and a battery” and application number 202211360477.1. Technical Field

[0002] The present invention relates to the technical field of batteries, and in particular to an electrode sheet and a battery. Background Art

[0003] At present, in the preparation process of multi-layer dry-process electrode sheets on the market, the multi-layer electrode film and the current collector are usually rolled together.

[0004] The rolling process compresses adjacent electrode membranes into a whole, which often leads to excessive compaction density between adjacent electrode membranes, which is not conducive to electrolyte infiltration. Summary of the Invention

[0005] The object of the present invention is to provide a method for preparing an electrode sheet, which can prepare an electrode sheet that is more conducive to electrolyte infiltration.

[0006] Another object of the present invention is to provide an electrode sheet that is easy to be wetted by electrolyte.

[0007] Another object of the present invention is to provide an electrode sheet having better charge and discharge performance.

[0008] The embodiment of the present invention provides a technical solution: A method for preparing an electrode sheet, comprising: The electrode materials are respectively prepared into a first electrode film and a second electrode film by a dry film forming method, wherein the electrode materials include an active material, a conductive agent and a binder; performing embossing on the first electrode film to form concave-convex patterns on at least one side of the first electrode film; Roll-pressing the second electrode film onto the side of the first electrode film on which the concave-convex pattern is formed, to obtain a composite laminate; The composite laminate is rolled and laminated on a current collector to obtain an electrode sheet.

[0009] Furthermore, the step of embossing the first electrode film to form concave-convex patterns on at least one side of the first electrode film includes: The first electrode film is subjected to single-side embossing to form the concave-convex pattern on one side of the first electrode film.

[0010] Furthermore, the step of embossing the first electrode film to form concave-convex patterns on at least one side of the first electrode film includes: The first electrode film is embossed on both sides to form the concave-convex patterns on both sides of the first electrode film.

[0011] Furthermore, the step of rolling the composite laminate onto a current collector to obtain an electrode sheet includes: The side of the composite laminate corresponding to the first electrode film away from the second electrode film is rolled and laminated on the current collector to obtain the electrode sheet.

[0012] Furthermore, the mass ratio of the active material in the first electrode film is greater than the mass ratio of the active material in the second electrode film.

[0013] Furthermore, the step of rolling the composite laminate onto a current collector to obtain an electrode sheet includes: The side of the composite laminate corresponding to the second electrode film away from the first electrode film is rolled and laminated on the current collector to obtain the electrode sheet.

[0014] Furthermore, the mass ratio of the active material in the first electrode film is smaller than the mass ratio of the active material in the second electrode film.

[0015] Furthermore, the step of rolling the composite laminate onto a current collector to obtain an electrode sheet includes: The two composite laminates are respectively rolled and laminated on both sides of the current collector to obtain the electrode sheet.

[0016] An embodiment of the present invention also provides an electrode sheet, which is prepared according to the electrode sheet preparation method, and the electrode sheet preparation method includes: using a dry film forming method to prepare the electrode material into a first electrode film and a second electrode film respectively, wherein the electrode material includes an active substance, a conductive agent and an adhesive; embossing the first electrode film to form concave and convex patterns on at least one side of the first electrode film; roll-combining the second electrode film on the side of the first electrode film on which the concave and convex patterns are formed to obtain a composite laminate; roll-combining the composite laminate on a current collector to obtain an electrode sheet.

[0017] An embodiment of the present invention also provides a battery, comprising the electrode sheet, which is prepared according to the electrode sheet preparation method, and the electrode sheet preparation method comprises: using a dry film forming method to prepare the electrode material into a first electrode film and a second electrode film respectively, wherein the electrode material includes an active substance, a conductive agent and an adhesive; embossing the first electrode film to form concave and convex patterns on at least one side of the first electrode film; rolling and compounding the second electrode film on the side of the first electrode film on which the concave and convex patterns are formed to obtain a composite laminate; rolling and compounding the composite laminate on a current collector to obtain an electrode sheet.

[0018] Compared to the prior art, the electrode sheet preparation method provided by the present invention embosses the first electrode film. When the second electrode film is roll-pressed and laminated onto the side of the first electrode film with the concave-convex pattern, the relatively raised portions of the concave-convex pattern provide support, thereby reducing the compaction density of the other non-raised portions. Under the same rolling force, the compaction density of the non-raised portions is lower, which is more conducive to the penetration of electrolyte between the first and second electrode films, avoiding the formation of black spots, increasing capacity, and preventing cycle drop. Therefore, the beneficial effects of the electrode sheet preparation method provided by the present invention include: being able to produce an electrode sheet that is more conducive to sufficient electrolyte infiltration. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly describes the drawings required for use in the embodiments. It should be understood that the following drawings illustrate only certain embodiments of the present invention and should not be construed as limiting the scope of the present invention. Those skilled in the art can, without inventive effort, derive other relevant drawings from these drawings.

[0020] Figure 1 A flowchart of a method for preparing an electrode sheet according to an embodiment of the present invention; Figure 2 is a schematic structural diagram of the first electrode film after embossing; Figure 3 is a schematic diagram of the structure of the composite laminate; Figure 4 Schematic diagram of the electrode structure.

[0021] Icon: 100 - electrode sheet; 110 - composite laminate; 111 - first electrode film; 1111 - concave-convex pattern; 112 - second electrode film; 120 - current collector. DETAILED DESCRIPTION

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the embodiments of the present invention. It should be understood that the described embodiments are only a portion of the embodiments of the present invention, not all of them. Generally, the components of the embodiments of the present invention described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0024] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0025] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. These are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0026] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0027] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, terms such as "disposed" and "connected" should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can also mean internal communication between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0028] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0029] Example See also Figure 1 , Figure 1The figure shows a flow chart of the electrode sheet preparation method provided in this embodiment. The electrode sheet preparation method may include the following steps: In step S101 , electrode materials are respectively prepared into a first electrode film 111 and a second electrode film 112 by using a dry film forming method.

[0030] The first electrode film 111 and the second electrode film 112 are both made of electrode materials, which include active materials, conductive agents, and adhesives. In this embodiment, the active materials are negative electrode active materials such as graphite or silicon.

[0031] Furthermore, the electrode sheet preparation method may further include: Step S102 : performing embossing treatment on the first electrode film 111 to form concave-convex patterns 1111 on at least one side of the first electrode film 111 .

[0032] After the first electrode film 111 and the second electrode film 112 are prepared, the first electrode film 111 is embossed so that a concave-convex pattern 1111 is formed on at least one side of the first electrode film 111 .

[0033] Please refer to Figure 2 , Figure 2 FIG. 1 is a schematic structural diagram of the first electrode film 111 after embossing.

[0034] In this embodiment, the first electrode film 111 is embossed on both sides, so that concave-convex patterns 1111 are formed on both sides of the first electrode film 111 .

[0035] In other embodiments, the first electrode film 111 may be embossed on one side according to actual application conditions, so as to form concave-convex patterns 1111 on one side of the first electrode film 111 .

[0036] The embossing process can use a pattern roller with an uneven surface, and the cross section of the raised part can be a rectangular, triangular or other structure.

[0037] Please continue reading Figure 1 Furthermore, the electrode sheet preparation method may further include: In step S103 , the second electrode film 112 is rolled and laminated onto the side of the first electrode film 111 where the concave-convex pattern 1111 is formed, to obtain a composite laminate 110 .

[0038] Please refer to Figure 3 , Figure 3 FIG. 1 is a schematic structural diagram of a composite laminate 110 .

[0039] In this embodiment, since the concavo-convex patterns 1111 are formed on both sides of the first electrode film 111, the second electrode film 112 can be roll-laminated onto either side of the first electrode film 111. In another embodiment, when the concavo-convex patterns 1111 are formed on only one side of the first electrode film 111, the second electrode film 112 needs to be roll-laminated onto the side of the first electrode film 111 where the concavo-convex patterns 1111 exist.

[0040] It can be understood that in the process of roll-combining the second electrode film 112 and the first electrode film 111, since the first electrode film 111 is formed with concave-convex patterns 1111, the raised portions of the concave-convex patterns 1111 are first subjected to force and play a supporting role, so that other non-raised portions on the first electrode film 111 obtain smaller extrusion pressure, thereby reducing the compaction density of the non-raised portions.

[0041] Under the same rolling force, the compaction density of the non-raised part is smaller, which is more conducive to the electrolyte penetrating between the first electrode film 111 and the second electrode film 112, making the electrolyte infiltration more sufficient, avoiding the generation of black spots, increasing capacity and preventing cycle diving.

[0042] Please continue reading Figure 1 Furthermore, the electrode sheet preparation method may further include: Step S104 , rolling the composite laminate 110 onto the current collector 120 to obtain the electrode sheet 100 .

[0043] Please refer to Figure 4 , Figure 4 FIG. 1 is a schematic structural diagram of the electrode sheet 100 .

[0044] In this embodiment, since both sides of the first electrode film 111 are formed with concave and convex patterns 1111, in order to further improve the electrolyte infiltration speed and sufficiency, the side of the first electrode film 111 away from the second electrode film 112 is roll-compounded on the current collector 120 to obtain the electrode sheet 100.

[0045] Similarly, since the side where the first electrode film 111 and the current collector 120 are composited has a concave-convex pattern 1111, when the composite laminate 110 is rolled and composited on the current collector 120, the raised portion of the concave-convex pattern 1111 is first squeezed and plays a supporting role, so that the other non-raised portions on the first electrode film 111 obtain a smaller squeezing force, thereby reducing the compaction density of the non-raised portions.

[0046] Under the same rolling force, the compaction density of the non-raised portion is smaller, which is more conducive to the electrolyte penetrating between the first electrode film 111 and the current collector 120, making the electrolyte infiltration faster and more sufficient.

[0047] Furthermore, the mass ratio of the active material in the first electrode film 111 is greater than the mass ratio of the active material in the second electrode film 112. In this embodiment, the active material in the first electrode film 111 is graphite, and the active material in the second electrode film 112 is silicon material. That is, the first electrode film 111 is a low-capacity film, and the second electrode film 112 is a high-capacity film. The mass ratio of graphite to conductive agent and binder in the first electrode film 111 is 96:1:3, and the mass ratio of silicon material to conductive agent and binder in the second electrode film 112 is 95:1:4.

[0048] In another embodiment, when the first electrode film 111 is formed with a concave-convex pattern 1111 on only one side, and one side of the formed concave-convex pattern 1111 is roll-compounded with the second electrode film 112, the side of the composite stack 110 corresponding to the second electrode film 112 away from the first electrode film 111 can be roll-compounded on the current collector 120, or the side of the first electrode film 111 away from the second electrode film 112 can be roll-compounded on the current collector 120.

[0049] It should be noted that in the embodiment where the second electrode film 112 and the current collector 120 are combined together, the mass ratio of the active material in the first electrode film 111 is adjusted to be smaller than the mass ratio of the active material in the second electrode film 112 .

[0050] To improve energy density, in this embodiment, two composite laminates 110 are roll-laminated on both sides of a current collector 120 to form an electrode sheet 100. Furthermore, the two first electrode films 111 corresponding to the two composite laminates 110 are closely attached to opposite sides of the current collector 120, and the two corresponding second electrode films 112 are closely attached to the sides of the two first electrode films 111 facing away from the current collector 120.

[0051] In summary, the electrode sheet preparation method provided in this embodiment performs double-sided embossing treatment on the first electrode film 111. When the second electrode film 112 and the current collector 120 are respectively roll-compounded with the two sides of the first electrode film 111, the compaction density of the non-raised parts of the concave-convex patterns 1111 on both sides of the first electrode film 111 is smaller, which is more conducive to the immersion of electrolyte, avoids the generation of black spots, increases the capacity and provides a volume buffer for the electrode rebound to prevent cycle diving.

[0052] This embodiment also provides a Figure 4 The electrode sheet 100 shown is prepared by the aforementioned electrode sheet preparation method, and the first electrode film 111 is formed with concave and convex patterns 1111 on opposite sides. Therefore, the electrode sheet 100 has the characteristic of being more conducive to electrolyte infiltration, which can improve the charge and discharge performance of the battery cell used.

[0053] In addition, this embodiment further provides a battery, comprising the aforementioned electrode sheet 100. Therefore, the battery has the characteristic of better charge and discharge performance.

[0054] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. An electrode sheet, characterized in that: include: Composite laminates and current collectors; The composite laminate includes a first electrode film and a second electrode film, wherein at least one side of the first electrode film has concavo-convex lines, and the second electrode film is composited on the side of the first electrode film having the concavo-convex lines; The side of the composite stack corresponding to the first electrode film away from the second electrode film is composited on the current collector.

2. The electrode sheet according to claim 1, characterized in that The first electrode film is a low-capacity film, and the second electrode film is a high-capacity film.

3. The electrode sheet according to claim 1 or 2, characterized in that: The mass ratio of the active material in the first electrode film is greater than the mass ratio of the active material in the second electrode film. 4 . The electrode sheet according to claim 3 , wherein the active material in the first electrode film is graphite, and the active material in the second electrode film is silicon material.

5. The electrode sheet according to claim 1, characterized in that The first electrode film and the second electrode film are both composed of electrode materials, and the electrode materials include active materials, conductive agents and adhesives.

6. The electrode sheet according to claim 1, characterized in that The cross section of the raised portion of the concave-convex pattern is a rectangular or triangular structure.

7. A battery, characterized in that: The invention comprises an electrode sheet as described in any one of claims 1 to 6.

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