Negative electrode plate and its manufacturing method, battery cell, battery, and electronic device

Abstract

To provide a negative plate and a manufacturing method of the negative plate for obtaining a battery cell, a battery, and an electronic device that improve the capacity and energy density of the battery cell.SOLUTION: A negative plate includes a negative electrode current collector 1, a carbon quantum dot layer 2 formed on the surface of the negative electrode current collector 1, and a negative electrode silicon-containing coating layer 3 formed on the surface of the carbon quantum dot layer 2 away from the negative electrode current collector 1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to the field of terminal technology, and in particular to a negative plate and its manufacturing method, a battery cell, a battery, and an electronic device. [Background technology]

[0002] As the functions of electronic devices become more powerful, the amount of power required to maintain the normal operation of each function per unit time increases. Therefore, how to improve the capacity and energy density of battery cells to solve the durability problem of electronic devices has become a new driving force for research and development of current engineers. Summary of the Invention

[0003] The present disclosure provides a negative plate and a manufacturing method thereof, a battery cell, a battery, and an electronic device to address the deficiencies of the related art.

[0004] According to a first aspect of the embodiment of the present disclosure, A negative electrode current collector; a carbon quantum dot layer formed on a surface of the negative electrode current collector; and a negative electrode silicon-containing coating layer formed on a surface of the carbon quantum dot layer away from the negative electrode current collector.

[0005] Optionally, the negative electrode silicon-containing coating layer includes a silicon-containing coating layer and a graphite coating layer formed on a surface of the silicon-containing coating layer, and the silicon-containing coating layer is located between the graphite coating layer and the carbon quantum dot layer.

[0006] Optionally, the silicon-containing coating layer comprises a composite layer of a silicon material and graphite.

[0007] Optionally, the silicon-containing coating layer includes at least one of the following materials: silicon element, silicon oxide, and silicon carbide.

[0008] Optionally, the negative electrode current collector includes one of a copper current collector, a copper composite current collector, a nickel current collector, a nickel composite current collector, a carbon paper current collector, and a carbon fiber current collector.

[0009] According to a second aspect of the embodiment of the present disclosure, Obtaining a negative electrode current collector; Coating a carbon quantum dot layer on the surface of the negative electrode current collector; and coating a surface of the carbon quantum dot layer away from a negative electrode current collector with a negative electrode silicon-containing coating layer.

[0010] Optionally, the step of coating a carbon quantum dot layer on the surface of the negative electrode current collector includes: Mixing carbon quantum dots, an adhesive and a dispersant to obtain a mixed slurry; and coating the mixed slurry on a surface of the negative electrode current collector to obtain the carbon quantum dot layer.

[0011] Optionally, the step of coating a negative electrode silicon-containing coating layer on the surface of the carbon quantum dot layer includes: forming a silicon-containing coating layer on the surface of the carbon quantum dot layer; and forming a graphite coating layer on the surface of the silicon-containing coating layer.

[0012] Optionally, the step of forming a silicon-containing coating layer on the surface of the carbon quantum dot layer includes: Mixing graphite, a silicon material, and an adhesive to obtain a mixed slurry; and coating the mixed slurry on the surface of the carbon quantum dot layer to obtain the silicon-containing coating layer.

[0013] Optionally, the silicon material includes at least one of elemental silicon, silicon oxide, and silicon carbide.

[0014] Optionally, the step of forming a graphite coating layer on the surface of the silicon-containing coating layer includes: Mixing the graphite and the adhesive to obtain a mixed slurry; and coating the mixed slurry on the surface of the silicon-containing coating layer to obtain the graphite coating layer.

[0015] Optionally, the adhesive comprises at least one of polypropylene, polyethylene, sodium carboxymethylcellulose, polyvinylidene fluoride, and styrene butadiene rubber.

[0016] According to a third aspect of the embodiment of the present disclosure, A positive electrode plate; A negative electrode plate comprising the negative electrode plate according to any one of the above embodiments or the negative electrode plate obtained by the manufacturing method according to any one of the above embodiments; A separator disposed between the positive plate and the negative plate is provided.

[0017] According to a fourth aspect of an embodiment of the present disclosure, there is provided a battery including the battery cell according to any one of the above embodiments.

[0018] According to a fifth aspect of the embodiment of the present disclosure, there is provided an electronic device including the battery according to any one of the above embodiments.

[0019] The technical solutions provided by the embodiments of the present disclosure may include the following beneficial effects. As can be seen from the above examples, the present disclosure utilizes the characteristics that the specific capacity of the silicon material is higher than that of the negative electrode coating material in the prior art of lithium batteries, and the discharge potential is low, so that the energy density of the battery cell equipped with this negative electrode plate can be effectively increased; the carbon quantum dot layer can improve the conductivity of the negative electrode silicon-containing coating layer and reduce the interface impedance between the negative electrode current collector and the negative electrode silicon-containing coating layer; the flexibility of the carbon quantum dot layer provides a large volume change space and flexibility for the expansion of the negative electrode silicon-containing coating layer, improves the mechanical performance of the negative electrode silicon-containing coating layer, and reduces the risk of the negative electrode silicon-containing coating layer expanding and separating from the negative electrode current collector during charging and discharging.

[0020] It should be noted that the above general description and the following detailed description are merely for illustrative purposes and are not intended to limit the present application. [Brief description of the drawings]

[0021] The drawings herein are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention, and together with the specification serve to explain the principles of the invention. [Figure 1] FIG. 2 is a schematic diagram of a negative electrode plate according to an exemplary embodiment. [Diagram 2] FIG. 2 is a schematic diagram of another negative plate according to an exemplary embodiment. [Diagram 3] 4 is a flowchart of a method for manufacturing a negative plate according to an exemplary embodiment. [Figure 4] 4 is a flowchart of another method for manufacturing a negative plate according to an illustrative embodiment. [Diagram 5] 1 is a schematic cross-sectional view of a battery cell according to an exemplary embodiment; [Figure 6] FIG. 1 is a schematic diagram of a battery according to an exemplary embodiment. [Figure 7] 1 is a schematic exploded view of an electronic device according to an exemplary embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Reference will now be made in detail to illustrative embodiments, examples of which are illustrated in the drawings. Where the following description refers to the drawings, identical reference numerals in different drawings refer to the same or similar elements unless otherwise stated. The embodiments described in the following illustrative examples are not intended to represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention as set forth in the claims.

[0023] The terms used in this disclosure are for the purpose of describing particular embodiments only and are not intended to be limiting of the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "the," and "said" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It is also to be understood that the term "and / or" as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0024] In this disclosure, terms such as "first," "second," and "third" may be used to describe various pieces of information, but such information is not limited to these terms. These terms are used only to distinguish the same types of information from one another. For example, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information, without departing from the scope of this disclosure. Depending on the context, the word "if..." as used herein may be interpreted as "when..." or "when..." or "in response to... a decision."

[0025] At present, with the development of science and technology, the configuration function of electronic devices is becoming stronger and stronger. In order to meet the durability requirements of electronic devices, higher requirements are put forward for the battery capacity of electronic devices. Usually, electronic devices may include lithium batteries. In order to improve the battery capacity of lithium batteries, researchers and engineers have considered how to expand the volume of the battery chamber of electronic devices and how to reduce the size of the occupied space of other layer structures of lithium batteries to increase the capacity, but these proposals may conflict with the layout of other electronic components in the electronic device, while their contribution to the qualitative improvement of battery capacity and battery density is relatively small.

[0026] Therefore, in order to be compatible with the increasingly powerful performance and durability requirements of electronic devices, the present disclosure provides a negative electrode plate 100 as shown in FIG. 1, which includes a negative electrode current collector 1, a carbon quantum dot layer 2, and a negative electrode silicon-containing coating layer 3, where the carbon quantum dot layer 2 can be formed on the surface of the negative electrode current collector 1, and the negative electrode silicon-containing coating layer 3 can be formed on the surface of the carbon quantum dot layer 2 away from the negative electrode current collector 1, that is, the carbon quantum dot layer 2 can be formed between the negative electrode silicon-containing coating layer 3 and the negative electrode current collector 1. Here, the size of the carbon quantum dots contained in the carbon quantum dot layer 2 can be relatively small, for example, 10 nm or less. The negative electrode current collector 1 includes one of a copper current collector, a copper composite current collector, a nickel current collector, a nickel composite current collector, a carbon paper current collector, and a carbon fiber current collector, and the present disclosure is not limited thereto.

[0027] As can be seen from the above examples, the specific capacity of the silicon material is higher than that of the negative electrode coating material in the prior art of lithium batteries, and the discharge potential is low, making it possible to effectively increase the energy density of the battery cell equipped with this negative electrode plate 100. In addition, a carbon quantum dot layer 2 is formed between the negative electrode silicon-containing coating layer 3 and the negative electrode current collector 1, and the carbon quantum dot layer 2 can improve the conductivity of the negative electrode silicon-containing coating layer 3 and reduce the interface impedance between the negative electrode current collector 1 and the negative electrode silicon-containing coating layer 3. In addition, since the size of the carbon quantum dots contained in the carbon quantum dot layer 2 is very small, it can provide a large volume change space and flexibility ability for the expansion of the negative electrode silicon-containing coating layer 3 during charging and discharging, improving the mechanical performance of the negative electrode silicon-containing coating layer 3 and reducing the risk of the negative electrode silicon-containing coating layer 3 expanding and separating from the negative electrode current collector 1 during charging and discharging. In addition, by coating the negative electrode current collector 1 with the carbon quantum dot layer 2, the size of the carbon quantum dots in the carbon quantum dot layer 2 is very small, which improves the compression density of the negative electrode plate 100 to a certain extent, and is advantageous for further increasing the energy density of the negative electrode plate 100.

[0028] In addition, when the silicon-containing material is used as the negative electrode coating material of the negative electrode plate 100, a large amount of lithium ions are inserted and extracted into the negative electrode silicon-containing coating layer 3, which causes a volume change of the negative electrode silicon-containing coating layer 3, which is easy to damage the silicon negative electrode active particles in the negative electrode silicon-containing coating layer 3, which leads to poor contact of the silicon negative electrode active particles, and the solid electrolyte interface film formed during the first charge and discharge becomes unstable. Therefore, in order to solve this problem, in the technical solution of the present disclosure, as shown in FIG. 2, the negative electrode silicon-containing coating layer 3 may include a silicon-containing coating layer 31 and a graphite coating layer 32 formed on the surface of the silicon-containing coating layer 31, and the silicon-containing coating layer 31 may be located between the graphite coating layer 32 and the carbon quantum dot layer 2. In this way, the graphite coating layer 32 can avoid the direct contact between the silicon-containing coating layer 31 and the electrolyte and reduce the reaction between the silicon-containing coating layer 31 and the electrolyte. The graphite coating layer 32 can contact and react with the electrolyte to form a solid electrolyte interface film, which is advantageous for improving the cycle life and multiplication characteristics of a battery equipped with the negative electrode plate 100, since the solid electrolyte interface film formed in the present disclosure is more stable than the technical proposal for contacting the electrolyte with the silicon negative electrode to form a solid electrolyte interface film. In addition, since the graphite coating layer 32 is coated on the surface of the silicon-containing coating layer 31, when the thickness of the negative electrode silicon-containing coating layer 3 is the same, the graphite coating layer 32 can alleviate the expansion of the silicon-containing coating layer 31 compared with a single layer of silicon-containing coating. In addition, since the graphite coating layer 32 has a large flexibility, it can buffer the diffusion of lithium ions and promote the uniform desorption of lithium ions, thereby further alleviating the expansion of the silicon-containing coating layer 31. Here, the silicon-containing coating layer 31 can include a composite layer of a silicon material and graphite, where the silicon material may include at least one material selected from the group consisting of silicon simple substance, silicon oxide, and silicon carbide.

[0029] As shown in FIG. 3, the present disclosure further provides a method for manufacturing the negative electrode plate 100, which may include the following steps.

[0030] In step 301, a negative electrode current collector 1 is obtained.

[0031] In this embodiment, the negative electrode current collector 1 may adopt one of a copper current collector, a copper composite current collector, a nickel current collector, a nickel composite current collector, a carbon paper current collector, and a carbon fiber current collector, and the present disclosure is not limited thereto.

[0032] In step 302, a carbon quantum dot layer 2 is coated on the surface of a negative electrode current collector.

[0033] In this embodiment, first, a slurry containing carbon quantum dots is obtained, and then the slurry is coated on the surface of the negative electrode current collector 1 to form a carbon quantum dot layer. Specifically, a mixed slurry is obtained by mixing carbon quantum dots, an adhesive, a dispersant, and an additive, and the mixed slurry is coated on the surface of the negative electrode current collector 1 to form a carbon quantum dot layer. Here, the adhesive may include at least one of polypropylene, polyethylene, sodium carboxymethylcellulose, polyvinylidene fluoride, and styrene butadiene rubber. The dispersant may include at least one of sodium carboxymethylcellulose, triethylhexyl phosphate, sodium lauryl sulfate, methylpentanol, cellulose derivatives, and polyacrylamide. The additive may include at least one of organic additives and inorganic additives.

[0034] In step 303, an anode silicon-containing coating layer is formed on the surface of the carbon quantum dot layer 2 away from the anode current collector 1.

[0035] In this embodiment, first, a silicon-containing coating layer 31 is formed on the surface of the carbon quantum dot layer 2 away from the negative electrode current collector 1, and then a graphite coating layer 32 is formed on the surface of the silicon-containing coating layer 31. The graphite coating layer 32 can reduce the expansion of the silicon-containing coating layer 31, and the graphite coating layer 32 and the electrolyte can form a solid electrolyte interface film, which is more stable than the solid electrolyte interface film formed by the reaction between the membrane layer containing a silicon material and the electrolyte.

[0036] Specifically, a mixed slurry is obtained by mixing graphite, a silicon material, an additive, a dispersant, and an adhesive, and then the mixed slurry is coated on the surface of the carbon quantum dot layer to obtain a silicon-containing coating layer 31; and a mixed slurry is obtained by mixing graphite, an adhesive, a conductive agent, a dispersant, and an additive, and the mixed slurry is coated on the surface of the silicon-containing coating layer 31 to form a graphite coating layer 32. Here, the silicon material includes at least one of silicon element, silicon oxide, and silicon carbide, and the adhesive in the mixed slurry forming the silicon-containing coating layer 31 and the mixed slurry forming the graphite coating layer 32 may include at least one of polypropylene, polyethylene, sodium carboxymethylcellulose, polyvinylidene fluoride, and styrene butadiene rubber. The dispersant may include at least one of sodium carboxymethylcellulose, triethylhexyl phosphate, sodium lauryl sulfate, methylpentanol, cellulose derivatives, and polyacrylamide. The additive may include at least one of organic additives and inorganic additives. Here, the adhesives, additives and dispersants contained in the silicon-containing coating layer 31, the graphite coating layer 32 and the carbon quantum dot layer 2 can be the same or different, and the present disclosure is not limited thereto.

[0037] To describe in detail the technical solution provided by the present disclosure, as shown in FIG. 4, the manufacturing method of the negative electrode plate 100 may include the following steps.

[0038] In step 401, a negative electrode current collector is obtained.

[0039] In step 402, a mixed slurry is obtained by mixing carbon quantum dots, an adhesive, and a dispersant.

[0040] In step 403, the mixed slurry is coated on the surface of the negative electrode current collector to obtain the carbon quantum dot layer.

[0041] In this embodiment, the mass content of the adhesive is 0.1%-5% of the total mass of the mixed slurry, the mass content of the dispersant is 0.1%-5% of the total mass of the mixed slurry, and the percentage relationship between the mass content of the carbon quantum dots and the total mass of the mixed slurry can be determined according to the concentration requirements of the carbon quantum dots. The concentration of the carbon quantum dots is related to the thickness of the carbon quantum dot layer 2, and the thicker the thickness, the higher the concentration of the carbon quantum dots. Therefore, in the actual processing, the mass of the carbon quantum dots can be determined by selecting an appropriate concentration according to the thickness requirements of the carbon quantum dot layer 2. In other embodiments, the mixed slurry may further include an additive, and the mass content of the additive is 0%-50% of the total mass of the mixed slurry.

[0042] In step 404, a mixed slurry is obtained by mixing the graphite, the silicon material and the adhesive.

[0043] In step 405, the mixed slurry is coated on the surface of the carbon quantum dot layer to obtain the silicon-containing coating layer.

[0044] In this embodiment, the mass content of the silicon material is 0.1%-45% of the total mass of the mixed slurry, the mass content of the adhesive is 0.05%-5% of the total mass of the mixed slurry, and the remaining proportion is the graphite material. In another embodiment, the mixed slurry may further include an additive and a dispersant, the mass content of the additive is 0%-25% of the total mass of the mixed slurry, and the mass content of the dispersant is 0%-10% of the total mass of the mixed slurry.

[0045] In step 406, the graphite and the adhesive are mixed to form a mixed slurry.

[0046] In step 407, the mixed slurry is coated on the surface of the silicon-containing coating layer to obtain the graphite coating layer.

[0047] In this embodiment, the mass content of the graphite material is 80%-99.9% of the total mass of the mixed slurry, and the mass content of the adhesive is 0.1%-5% of the total mass of the mixed slurry. In another embodiment, the mixed slurry may further include an additive, a conductive agent, and a dispersant, and the mass content of the conductive agent is 0%-5% of the total mass of the mixed slurry, the mass content of the dispersant is 0-5% of the total mass of the mixed slurry, and the mass content of the additive is 0-20% of the total mass of the mixed slurry.

[0048] Based on the embodiments of the present disclosure, as shown in Fig. 5, the present disclosure further provides a battery cell 200, which may include a positive plate (not shown), a separator (not shown), and a negative plate 100 shown in any one of the above embodiments, and the separator is provided between the negative plate 100 and the positive plate, and the negative plate 100, the separator, and the positive plate can be stacked and then wound to obtain a wound battery cell as shown in Fig. 5. In fact, in other embodiments, the negative plate 100 may be used to form a stacked battery cell, but the present disclosure is not limited thereto.

[0049] Based on the technical solution of the present disclosure, the present disclosure further provides a battery 300 as shown in FIG. 6 , which may include a battery cell 200, a housing 301 and a protection circuit board 302, in which the housing 301 is used to encapsulate and protect the battery cell 200, and the protection circuit board 302 is electrically connected to the positive and negative ears of the battery cell 200 respectively, so as to safely protect the charging and discharging of the battery 300.

[0050] 7, the electronic device 400 may include a battery compartment 401, an adhesive layer 402, and a battery 300, and the battery 300 may be attached in the battery compartment 401 via the adhesive layer 402. The electronic device 400 may include one or more of a mobile phone terminal, a tablet terminal, a wearable device, a smart furniture, and an electronic reader, and the present disclosure is not limited thereto.

[0051] Other implementations of the present disclosure will be readily apparent to those skilled in the art after making the present disclosure by reference to this specification. The present disclosure is intended to include any modification, use, or adaptation of the present disclosure according to the general principles of the present disclosure, and to encompass common knowledge or conventional technical means in the art that are not disclosed in the present disclosure. The specification and embodiments are exemplary only, and the scope and spirit of the present disclosure will be indicated by the appended claims.

[0052] It will be understood that the present disclosure is not limited to the exact construction illustrated in the drawings and described above, and that various modifications and changes can be made to the present disclosure without departing from the scope of the present disclosure, which is limited only by the appended claims.

Claims

1. A negative electrode plate, A negative electrode current collector; a carbon quantum dot layer formed on a surface of the negative electrode current collector; a negative electrode silicon-containing coating layer formed on a surface of the carbon quantum dot layer away from the negative electrode current collector; The carbon quantum dot layer is formed by a mixed slurry containing carbon quantum dots, an adhesive, a dispersant and an additive, the mass content of the adhesive is 0.1% to 5% of the total mass of the mixed slurry, the mass content of the dispersant is 0.1% to 5% of the total mass of the mixed slurry, the carbon quantum dots are made of conductive carbon, and the size of the carbon quantum dots is 10 nm or less; A negative electrode plate characterized by:

2. The negative electrode silicon-containing coating layer includes a silicon-containing coating layer and a graphite coating layer formed on the surface of the silicon-containing coating layer, and the silicon-containing coating layer is located between the graphite coating layer and the carbon quantum dot layer; The negative electrode plate according to claim 1 .

3. The silicon-containing coating layer comprises a composite layer of a silicon material and graphite; The negative electrode plate according to claim 2 .

4. The silicon-containing coating layer contains at least one material selected from the group consisting of silicon element, silicon oxide, and silicon carbide. The negative electrode plate according to claim 2 .

5. The negative electrode current collector comprises one of a copper current collector, a copper composite current collector, a nickel current collector, a nickel composite current collector, a carbon paper current collector, and a carbon fiber current collector; The negative electrode plate according to claim 1 .

6. A method for manufacturing a negative electrode plate, comprising: Obtaining a negative electrode current collector; Coating a carbon quantum dot layer on the surface of the negative electrode current collector; and coating a negative electrode silicon-containing coating layer on a surface of the carbon quantum dot layer away from a negative electrode current collector; The carbon quantum dot layer is formed by a mixed slurry containing carbon quantum dots, an adhesive, a dispersant and an additive, the mass content of the adhesive is 0.1% to 5% of the total mass of the mixed slurry, the mass content of the dispersant is 0.1% to 5% of the total mass of the mixed slurry, the carbon quantum dots are made of conductive carbon, and the size of the carbon quantum dots is 10 nm or less; A method for manufacturing a negative electrode plate comprising the steps of:

7. The step of coating a carbon quantum dot layer on the surface of the negative electrode current collector includes: Mixing carbon quantum dots, an adhesive and a dispersant to obtain a mixed slurry; and coating the mixed slurry on a surface of the negative electrode current collector to obtain the carbon quantum dot layer. The method according to claim 6 .

8. The step of coating a negative electrode silicon-containing coating layer on the surface of the carbon quantum dot layer includes: forming a silicon-containing coating layer on the surface of the carbon quantum dot layer; forming a graphite coating layer on the surface of the silicon-containing coating layer; The method according to claim 6 .

9. The step of forming a silicon-containing coating layer on the surface of the carbon quantum dot layer includes: Mixing graphite, a silicon material, and an adhesive to obtain a mixed slurry; and coating the mixed slurry on the surface of the carbon quantum dot layer to obtain the silicon-containing coating layer. The method according to claim 8 .

10. The silicon material includes at least one material selected from the group consisting of silicon elemental material, silicon oxide, and silicon carbide. The method according to claim 9 .

11. The step of forming a graphite coating layer on the surface of the silicon-containing coating layer includes: Mixing the graphite and the adhesive to obtain a mixed slurry; and coating the mixed slurry on the surface of the silicon-containing coating layer to obtain the graphite coating layer. The method according to claim 8 .

12. the adhesive comprises at least one of polypropylene, polyethylene, sodium carboxymethyl cellulose, polyvinylidene fluoride, and styrene butadiene rubber; The method according to claim 7, 9 or 11.

13. A battery cell, A positive electrode plate; The negative electrode plate according to any one of claims 1 to 5, A separator provided between the positive electrode plate and the negative electrode plate. A battery cell comprising:

14. A battery cell comprising: A battery characterized by:

15. 15. A battery comprising the battery of claim 14.

1. An electronic device comprising:

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