A dry-process battery electrode sheet, a method of manufacturing the same, and a battery including the same

Abstract

The application provides a dry-process battery pole piece, a preparation method thereof and a battery. The preparation method comprises the following steps: a non-destructive mixing step, a centrifugal stirring step and a hot-pressing compounding step. The non-destructive mixing step comprises: non-destructively mixing an active material, a conductive agent and a fiberizable binder to obtain a first mixture. The centrifugal stirring step comprises: centrifugally fiberizing the first mixture without a centrifugal medium to obtain a second mixture. The hot-pressing compounding step comprises: sequentially performing hot pressing and calendering on the second mixture to obtain a calendered film, and then performing hot-pressing compounding on the calendered film and a foil to obtain the dry-process battery pole piece. The fiberization process of the material in the preparation method can avoid the damage to the particle structure of the active material, and thus the storage, high-temperature and cycle performances of the battery can be improved.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, specifically to a dry-process battery electrode, a method for preparing the same, and a battery including the electrode. Background Technology

[0002] Lithium-ion batteries are widely used in 3C products, energy storage, electric vehicles, and other fields due to their numerous advantages. Lithium-ion battery electrodes are typically manufactured using a wet process, which involves solvent evaporation during production, causing environmental pollution and increasing manufacturing costs.

[0003] Dry electrode manufacturing processes avoid the aforementioned problems by not adding solvents during battery electrode manufacturing. Currently, dry electrode processes typically involve mixing binders, conductive agents, and active materials before fiberization. Fiberization methods usually include shearing and stirring, mechanical grinding, and gas pulverization. For existing active materials, especially polycrystalline ternary materials, fiberization using these methods can easily damage the surface coating of particles and destroy the secondary particle agglomeration structure, affecting the material's storage, high-temperature performance, and cycle performance.

[0004] Therefore, how to fiberize the hybrid material without damaging the morphology and surface structure of the active particles is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] This invention provides a method for preparing dry-process battery electrodes, wherein the fiberization process of the material in this method can avoid damaging the particle structure of the active material.

[0006] According to the first aspect, one embodiment provides a method for preparing a dry-process battery electrode, comprising the following steps:

[0007] Non-destructive mixing step: The active material, conductive agent and fiber-forming binder are non-destructively mixed to obtain a first mixture;

[0008] Centrifugation step: The first mixture is centrifuged and fiberized without the use of a centrifugation medium to obtain a second mixture;

[0009] Hot-pressing composite step: The second mixture is hot-pressed and calendered in sequence to obtain a calendered film. Then, the calendered film is hot-pressed and laminated with the foil to obtain a dry-process battery electrode.

[0010] Furthermore, in the centrifugation step, the centrifugation speed is 1500-5000 RPM, the temperature inside the centrifuge container is 15-100℃, and the centrifugation time is 3-30 min.

[0011] Furthermore, the centrifugal rotation speed is 2000-3000 RPM.

[0012] According to the second aspect, one embodiment provides a battery electrode sheet prepared using the preparation method of the first aspect.

[0013] According to a third aspect, one embodiment provides a battery whose battery electrodes are prepared using the preparation method of the first aspect.

[0014] This invention provides a method for preparing dry-process battery electrodes. In this method, the process of fiberizing the binder is centrifugation. Since there is no centrifugal medium in the centrifuge container, the fiberization of the binder can be achieved during the centrifugation process of the binder, conductive agent and active material, while avoiding damage to the agglomeration structure and surface coating of the active material during the stirring process. This can improve the storage, high temperature and cycle performance of the battery. Attached Figure Description

[0015] Figure 1 This is a process flow diagram of the dry-process battery electrode fabrication process in one embodiment. Detailed Implementation

[0016] The present invention will be further described in detail below through specific embodiments. In the following embodiments, many details are described to facilitate a better understanding of this application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other materials or methods. In some cases, certain operations related to this application are not shown or described in the specification. This is to avoid obscuring the core parts of this application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0017] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification are only for clearly describing a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0018] To further illustrate this application, the following detailed description of a dry-process battery electrode, its preparation method, and the battery provided in this application is provided in conjunction with embodiments. However, it should be understood that these embodiments are implemented based on the technical solution of this application, and detailed implementation methods and specific operating procedures are given only to further illustrate the features and advantages of this application, and are not intended to limit the scope of protection of the claims of this application. The scope of protection of this application is not limited to the following embodiments.

[0019] Non-destructive mixing: In this application, for example, when the binder, active material and conductive agent are mixed, the mixing method does not damage the surface coating layer of the active material and the secondary particle agglomeration structure.

[0020] The principle of the present invention for fiberizing the binder by centrifugation is as follows: a first mixture including the binder to be fiberized is thrown onto the wall of a centrifuge tank under the action of centrifugal force. When the centrifugal force overcomes the inter-fiber force of the binder to be fiberized, the binder is stretched into fibers.

[0021] This invention provides a method for preparing dry-process battery electrodes, the flowchart of which is shown below. Figure 1 As shown, it includes the following steps:

[0022] Non-destructive mixing step: The active material, conductive agent and fiber-forming binder are non-destructively mixed to obtain a first mixture.

[0023] Centrifugation step: The first mixture is centrifuged and fiberized without the use of a centrifugation medium to obtain a second mixture.

[0024] Hot-pressing composite step: The second mixture is hot-pressed and calendered in sequence to obtain a calendered film. Then, the calendered film is hot-pressed and laminated with the foil to obtain a dry-process battery electrode.

[0025] In an embodiment of the present invention, a centrifuge container without centrifugal medium is used to centrifuge a first mixture including binder, conductive agent and active material. This can fiberize the binder while avoiding damage to the agglomeration structure and surface coating of the active material during stirring.

[0026] In one embodiment, during the centrifugation step, the centrifugal rotation speed is 1500-5000 RPM, preferably 2000-3000 RPM, the temperature inside the centrifuge container is 15-100℃, and the centrifugation time is 3-30 minutes. Controlling the centrifugal rotation speed, the temperature of the centrifuge container, and the centrifugation time during the centrifugation step ensures the effective fiberization of the adhesive while effectively avoiding damage to the agglomeration structure and surface coating of the active material.

[0027] In embodiments of the present invention, the non-destructive mixing step includes one of planetary mixing, three-dimensional mixing, or double-cone stirring.

[0028] In embodiments of the present invention, the dry-process battery electrode includes a positive electrode or a negative electrode.

[0029] The binder includes at least one of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), or sodium carboxymethyl cellulose (CMC). The active material includes either a positive or negative electrode active material; the positive electrode active material includes at least one of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium manganese oxide, lithium iron phosphate, or lithium iron manganese phosphate; the negative electrode active material includes at least one of graphite, silicon oxide, or silicon carbon. The conductive agent includes at least one of acetylene black, graphite, graphene, or carbon nanotubes.

[0030] In the hot-pressing lamination step, the hot-pressing temperature is 100-200℃, the calendering temperature is 100-200℃, and the temperature for hot-pressing the calendered film and foil together is 100-200℃.

[0031] An embodiment of the present invention also provides a battery electrode sheet, which is prepared by the aforementioned preparation method.

[0032] An embodiment of the present invention also provides a battery in which the electrode sheets are prepared using the aforementioned preparation method.

[0033] Example 1

[0034] This embodiment provides a method for preparing a positive dry electrode sheet, including the following steps:

[0035] Non-destructive mixing step: PTFE, acetylene black conductive agent SP, and lithium nickel cobalt manganese oxide (Ni:Co:Mn=5:2:3) were added to a planetary mixer at a mass ratio of 2.5:2:95.5 for non-destructive mixing to obtain the first mixture. The planetary mixer's revolution speed was 1500 RPM.

[0036] Centrifugation step: The first mixture is added to a centrifuge tank and centrifuged to obtain a second mixture. The centrifugation speed is 2500 RPM, the temperature inside the centrifuge tank is 45℃, and the centrifugation time is 15 min.

[0037] Hot-pressing lamination step: The second mixture is hot-pressed on a hot press to obtain a self-supporting film. The self-supporting film is then further hot-pressed and calendered to a thickness of 133 μm to obtain a calendered film. The calendered film and aluminum foil are then hot-pressed and laminated on a hot press to obtain a dry-process battery electrode. The hot-pressing temperature is 160℃, the hot-calendering temperature is 160℃, and the hot-pressing lamination temperature is 130℃.

[0038] The positive electrode sheet prepared in this embodiment can be used in lithium-ion batteries.

[0039] Example 2

[0040] This embodiment provides a method for preparing a dry negative electrode sheet, including the following steps:

[0041] Non-destructive mixing step: PTFE, acetylene black conductive agent SP, and active material graphite are added to a planetary mixer at a mass ratio of 3:2:95 for non-destructive mixing to obtain the first mixture. The planetary mixer's revolution speed is 2000 RPM.

[0042] Centrifugation step: The first mixture is added to a centrifuge tank and centrifuged to obtain a second mixture. The centrifugation speed is 2600 RPM, the temperature inside the centrifuge tank is 60℃, and the centrifugation time is 20 min.

[0043] Hot-pressing lamination step: The second mixture is hot-pressed on a hot press to obtain a self-supporting film. The self-supporting film is then further hot-pressed and calendered to a thickness of 128 μm to obtain a calendered film. The calendered film and copper foil are then hot-pressed and laminated on a hot press to obtain the negative electrode dry-process battery electrode sheet. The hot-pressing temperature is 150℃, the hot-calendering temperature is 150℃, and the hot-pressing lamination temperature is 120℃.

[0044] The negative electrode sheet prepared in this embodiment can be used in lithium-ion batteries.

[0045] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A method for preparing a dry-process battery electrode, characterized in that, Includes the following steps: Non-destructive mixing step: The active material, conductive agent and fiber-forming binder are non-destructively mixed to obtain a first mixture; Centrifugation step: Without using a centrifugal medium, the first mixture is centrifuged and fiberized, that is, the first mixture, including active material, conductive agent and binder to be fiberized, is thrown against the wall of the centrifuge tank under the action of centrifugal force. When the centrifugal force overcomes the inter-fiber force of the binder to be fiberized, the binder is stretched into fibers to obtain the second mixture; Hot pressing and lamination step: The second mixture is hot pressed and calendered in sequence to obtain a calendered film. Then, the calendered film is hot-pressed and laminated with foil to obtain a dry battery electrode.

2. The preparation method according to claim 1, characterized in that, In the centrifugation step, the centrifugal rotation speed is 1500-5000 RPM, the temperature inside the centrifuge container is 15-100℃, and the centrifugation time is 3-30 min.

3. The preparation method according to claim 2, characterized in that, The centrifugal rotation speed is 2000-3000 RPM.

4. The preparation method according to claim 1, characterized in that, The non-destructive mixing step includes one of planetary mixing, three-dimensional mixing, or double-cone stirring.

5. The preparation method according to any one of claims 1 to 4, characterized in that, The dry-process battery electrode includes a positive electrode or a negative electrode.

6. The preparation method according to claim 5, characterized in that, The adhesive includes at least one of polytetrafluoroethylene, polyvinylidene fluoride, polyethylene oxide, or sodium carboxymethyl cellulose. The active material includes a positive electrode active material or a negative electrode active material; The conductive agent includes at least one of acetylene black, graphite, graphene, or carbon nanotubes.

7. The preparation method according to claim 6, characterized in that, The positive electrode active material includes at least one of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium manganese oxide, lithium iron phosphate, or lithium iron manganese phosphate. The negative electrode active material includes at least one of graphite, silicon oxide, or silicon carbon.

8. The preparation method according to claim 1, characterized in that, In the hot-pressing composite step, the hot-pressing temperature is 100-200℃; the calendering temperature is 100-200℃; and the temperature for hot-pressing the calendered film and foil together is 100-200℃.

9. The battery electrode sheet prepared by any one of claims 1-8.

10. A battery, characterized in that, The battery comprises battery electrodes prepared by any one of claims 1-8.

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