An electrode sheet preparation method, an electrode sheet and a battery

Abstract

The present invention discloses a method for preparing an electrode sheet, an electrode sheet and a battery, which relate to the technical field of batteries. The method for preparing the electrode sheet includes: respectively preparing a first electrode film and a second electrode film from electrode materials by a dry film forming method, wherein the electrode materials include active substances, conductive agents and binders; performing embossing treatment on the first electrode film to form concave and convex patterns on at least one side of the first electrode film; roll-compounding the second electrode film on the side of the first electrode film with the concave and convex patterns formed thereon to obtain a composite laminate; and roll-compounding the composite laminate on a current collector to obtain an electrode sheet. The method for preparing the electrode sheet provided by the present invention can prepare an electrode sheet that is more conducive to the full infiltration of the electrolyte.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and more particularly, to a method for preparing an electrode sheet, an electrode sheet and a battery. Background Art

[0002] Currently, in the preparation process of multi-layer dry electrode sheets on the market, multi-layer electrode films are usually roll-compounded with current collectors.

[0003] The roll-pressing process presses adjacent electrode films into a whole, often resulting in too high a compaction density between adjacent electrode films, which is not conducive to electrolyte infiltration. Summary of the Invention

[0004] The purpose 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.

[0005] Another purpose of the present invention is to provide an electrode sheet, which has the characteristic of facilitating electrolyte infiltration.

[0006] Still another purpose of the present invention is to provide an electrode sheet, which has the characteristic of better charge and discharge performance.

[0007] An embodiment of the present invention provides a technical solution:

[0008] A method for preparing an electrode sheet, comprising:

[0009] Using a dry film-forming method to separately prepare a first electrode film and a second electrode film from electrode materials, wherein the electrode materials include active substances, conductive agents and binders;

[0010] Performing embossing treatment on the first electrode film to form concave and convex patterns on at least one side of the first electrode film;

[0011] Roll-compounding the second electrode film on the side of the first electrode film where the concave and convex patterns are formed to obtain a composite laminate;

[0012] Roll-compounding the composite laminate on a current collector to obtain an electrode sheet.

[0013] Further, the step of performing embossing treatment on the first electrode film to form concave and convex patterns on at least one side of the first electrode film includes:

[0014] Performing single-sided embossing on the first electrode film to form the concave and convex patterns on one side of the first electrode film.

[0015] Further, the step of performing embossing treatment on the first electrode film to form concave and convex patterns on at least one side of the first electrode film includes:

[0016] The first electrode film is embossed on both sides to form the concave and convex patterns on both sides of the first electrode film.

[0017] Further, the step of roll-compounding the composite laminate on the current collector to obtain the electrode sheet includes:

[0018] Roll-compound the side of the composite laminate corresponding to the side of the first electrode film away from the second electrode film on the current collector to obtain the electrode sheet.

[0019] Further, 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.

[0020] Further, the step of roll-compounding the composite laminate on the current collector to obtain the electrode sheet includes:

[0021] Roll-compound the side of the composite laminate corresponding to the side of the second electrode film away from the first electrode film on the current collector to obtain the electrode sheet.

[0022] Further, the mass ratio of the active material in the first electrode film is less than the mass ratio of the active material in the second electrode film.

[0023] Further, the step of roll-compounding the composite laminate on the current collector to obtain the electrode sheet includes:

[0024] Roll-compound the two composite laminates on both sides of the current collector respectively to obtain the electrode sheet.

[0025] An embodiment of the present invention further provides an electrode sheet, which is prepared according to the electrode sheet preparation method described above. The electrode sheet preparation method includes: using a dry film-forming method to prepare an electrode material into a first electrode film and a second electrode film respectively, wherein the electrode material includes an active material, a conductive agent and an adhesive; performing embossing treatment on the first electrode film to form concave and convex patterns on at least one side of the first electrode film; roll-compounding the second electrode film on the side of the first electrode film where the concave and convex patterns are formed to obtain a composite laminate; roll-compounding the composite laminate on a current collector to obtain the electrode sheet.

[0026] An embodiment of the present invention further provides a battery, including the electrode sheet prepared according to the electrode sheet preparation method, and the electrode sheet preparation method includes: preparing a first electrode film and a second electrode film from electrode materials respectively by a dry film forming method, wherein the electrode materials include active substances, conductive agents and binders; performing embossing treatment on the first electrode film to form concave and convex patterns on at least one side of the first electrode film; roll-compounding the second electrode film on the side of the first electrode film with the concave and convex patterns formed thereon to obtain a composite laminate; and roll-compounding the composite laminate on a current collector to obtain an electrode sheet.

[0027] Compared with the prior art, in the electrode sheet preparation method provided by the present invention, the first electrode film is subjected to embossing treatment. When the second electrode film is roll-compounded on the side of the first electrode film with the concave and convex patterns formed thereon, the relatively convex portions of the concave and convex patterns form supports, thereby reducing the compaction density of other non-convex portions. Under the same roll-compression force, the compaction density of the non-convex portions is smaller, which is more conducive to the electrolyte infiltrating between the first electrode film and the second electrode film, avoiding the generation of black spots, improving the capacity and preventing cycling degradation. Therefore, the beneficial effects of the electrode sheet preparation method provided by the present invention include: being able to prepare an electrode sheet that is more conducive to the full infiltration of the electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 It is a flowchart of the electrode sheet preparation method provided by the embodiment of the present invention;

[0030] Figure 2 It is a structural schematic diagram of the first electrode film after embossing treatment;

[0031] Figure 3 It is a structural schematic diagram of the composite laminate;

[0032] Figure 4 It is a structural schematic diagram of the electrode sheet.

[0033] Reference numerals: 100 - electrode sheet; 110 - composite laminate; 111 - first electrode film; 1111 - concave and convex patterns; 112 - second electrode film; 120 - current collector. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Components of the embodiments of the present invention usually described and illustrated in the drawings herein can be arranged and designed in a variety of different configurations.

[0035] Therefore, the detailed description of the embodiments of the present invention provided in the drawings below is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0036] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0037] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, or the orientation or positional relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0038] In addition, the terms "first", "second", etc. are only used for descriptive distinction and should not be construed as indicating or implying relative importance.

[0039] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, terms such as "arrangement", "connection" should be understood in a broad sense. For example, "connection" can be 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, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] The following will describe in detail the specific implementation manners of the present invention with reference to the accompanying drawings.

[0041] Embodiment

[0042] Please refer to Figure 1 , Figure 1The flowchart of the electrode sheet preparation method provided by this embodiment is shown below. The electrode sheet preparation method may include the following steps:

[0043] Step S101, using the dry film forming method to separately prepare a first electrode film 111 and a second electrode film 112 from the electrode material.

[0044] Both the first electrode film 111 and the second electrode film 112 are composed of the electrode material, and the electrode material includes an active material, a conductive agent, and a binder. In this embodiment, the active material is selected from negative electrode active materials such as graphite or silicon material.

[0045] Further, the electrode sheet preparation method may further include:

[0046] 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.

[0047] After the first electrode film 111 and the second electrode film 112 are prepared, embossing treatment is performed on the first electrode film 111, so that concave-convex patterns 1111 are formed on at least one side of the first electrode film 111.

[0048] Please refer to Figure 2 , Figure 2 The structural schematic diagram of the first electrode film 111 after embossing treatment is shown.

[0049] In this embodiment, double-sided embossing is performed on the first electrode film 111 to form concave-convex patterns 1111 on both sides of the first electrode film 111.

[0050] In other embodiments, according to actual application conditions, single-sided embossing may be performed on the first electrode film 111 to form concave-convex patterns 1111 on one side of the first electrode film 111.

[0051] The embossing treatment may use a pattern roller with an uneven surface, and the cross-section of the protruding part may be a rectangular, triangular or other structures.

[0052] Please continue to refer to Figure 1 , further, the electrode sheet preparation method may further include:

[0053] Step S103, roll-compounding the second electrode film 112 onto the side of the first electrode film 111 where the concave-convex patterns 1111 are formed to obtain a composite laminate 110.

[0054] Please refer to Figure 3 , Figure 3 The structural schematic diagram of the composite laminate 110 is shown.

[0055] In this embodiment, since the uneven patterns 1111 are formed on both sides of the first electrode film 111, the second electrode film 112 can be roll-compounded on either side of the first electrode film 111. In another embodiment, when the uneven patterns 1111 are formed only on one side of the first electrode film 111, the second electrode film 112 needs to be roll-compounded on the side where the uneven patterns 1111 exist on the first electrode film 111.

[0056] It can be understood that during the process of roll-compounding the second electrode film 112 with the first electrode film 111, since the uneven patterns 1111 are formed on the first electrode film 111, the protruding parts of the uneven patterns 1111 are the first to be stressed and play a supporting role, so that the other non-protruding parts on the first electrode film 111 receive a smaller extrusion force, thereby reducing the compaction density of the non-protruding parts.

[0057] Under the same roll pressure, the compaction density of the non-protruding parts is smaller, which is more conducive to the electrolyte infiltrating between the first electrode film 111 and the second electrode film 112, making the electrolyte infiltration more sufficient, avoiding the generation of black spots, improving the capacity and preventing cycle diving.

[0058] Please continue to refer to Figure 1 , further, the method for preparing the electrode sheet may further include:

[0059] Step S104, roll-compounding the composite laminate 110 on the current collector 120 to obtain the electrode sheet 100.

[0060] Please refer to Figure 4 , Figure 4 as shown in the structural schematic diagram of the electrode sheet 100.

[0061] In this embodiment, since the uneven patterns 1111 are formed on both sides of the first electrode film 111, therefore, 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.

[0062] Similarly, since the side of the first electrode film 111 compounded with the current collector 120 has the uneven patterns 1111, when the composite laminate 110 is roll-compounded on the current collector 120, the protruding parts of the uneven patterns 1111 are first subjected to the extrusion action and play a supporting role, so that the other non-protruding parts on the first electrode film 111 receive a smaller extrusion force, thereby reducing the compaction density of the non-protruding parts.

[0063] Under the same roll pressure, the compaction density of the non-protruding parts is smaller, which is more conducive to the electrolyte infiltrating between the first electrode film 111 and the current collector 120, making the electrolyte infiltration faster and more sufficient.

[0064] Moreover, the mass ratio of the active material in the first electrode film 111 is greater than that 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, conductive agent and binder in the first electrode film 111 is 96:1:3, and the mass ratio of silicon material, conductive agent and binder in the second electrode film 112 is 95:1:4.

[0065] In another embodiment, when the first electrode film 111 is formed with concave-convex patterns 1111 only on one side, and the side with the formed concave-convex patterns 1111 is roll-compounded with the second electrode film 112, the composite laminate 110 corresponding to the side of 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.

[0066] It should be noted that in the embodiment where the second electrode film 112 is compounded with the current collector 120, the mass ratio of the active material in the first electrode film 111 is adjusted to be less than that in the second electrode film 112.

[0067] To improve the energy density, in this embodiment, the two composite laminates 110 are respectively roll-compounded on both sides of the current collector 120 to obtain the electrode sheet 100. Moreover, the two first electrode films 111 corresponding to the two composite laminates 110 are respectively pressed against the opposite sides of the current collector 120, and the corresponding two second electrode films 112 are respectively pressed against the sides of the two first electrode films 111 away from the current collector 120.

[0068] In summary, in the method for preparing the electrode sheet provided in this embodiment, the first electrode film 111 is subjected to double-sided embossing treatment. When the second electrode film 112 and the current collector 120 are respectively roll-compounded with both sides of the first electrode film 111, the compaction density of the non-protruding parts of the concave-convex patterns 1111 on both sides of the first electrode film 111 is smaller, which is more conducive to the infiltration of the electrolyte, avoids the generation of black spots, improves the capacity and provides a volume buffer for the rebound of the electrode sheet, preventing cyclic voltage drop.

[0069] This embodiment also provides an electrode sheet 100 as Figure 4 shown. The electrode sheet 100 is prepared by the aforementioned method for preparing the electrode sheet, and concave-convex patterns 1111 are formed on both opposite sides of the first electrode film 111. Therefore, the electrode sheet 100 has the characteristic of being more conducive to electrolyte infiltration, and can improve the charge and discharge performance of the applied battery cell.

[0070] In addition, this embodiment also provides a battery, including the aforementioned electrode sheet 100. Therefore, this battery has the characteristics of better charge and discharge performance.

[0071] The foregoing are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing an electrode sheet, characterized in that, Comprising: The first electrode film and the second electrode film are respectively prepared from the electrode material by a dry film forming method, wherein the electrode material includes an active material, a conductive agent, and a binder; The first electrode film is embossed to form concave and convex patterns on at least one side of the first electrode film; The second electrode film is roll-compounded on the side of the first electrode film with the concave and convex patterns formed thereon to obtain a composite laminate; The composite laminate is roll-compounded on a current collector to obtain an electrode sheet; The step of roll-compounding the composite laminate on 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 roll-compounded on the current collector to obtain the electrode sheet; 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.

2. The method for preparing an electrode sheet according to claim 1, wherein The step of embossing the first electrode film to form concave and convex patterns on at least one side of the first electrode film includes: The first electrode film is unilaterally embossed to form the concave and convex patterns on one side of the first electrode film.

3. The method for preparing an electrode sheet according to claim 1, wherein The step of embossing the first electrode film to form concave and convex patterns on at least one side of the first electrode film includes: The first electrode film is bilaterally embossed to form the concave and convex patterns on both sides of the first electrode film.

4. The method for preparing an electrode sheet according to claim 1, wherein The step of roll-compounding the composite laminate on a current collector to obtain an electrode sheet includes: Two of the composite laminates are respectively roll-compounded on both sides of the current collector to obtain the electrode sheet.

5. An electrode sheet, characterized in that, The electrode sheet is prepared by the electrode sheet preparation method according to any one of claims 1-4.

6. A battery, characterized in that, Comprising the electrode sheet according to claim 5.

Images