Negative electrode sheet and manufacturing method thereof, battery cell, battery and electronic device

Abstract

The present disclosure relates to a negative electrode plate and a manufacturing method thereof, a battery cell, a battery and an electronic device. The negative electrode plate comprises: a negative electrode current collector; a carbon quantum dot layer, the carbon quantum dot layer is formed on the surface of the negative electrode current collector; and a negative electrode silicon-containing coating layer, the negative electrode silicon-containing coating layer is formed on the surface of the carbon quantum dot layer away from the negative electrode current collector.

Description

Technical Field

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

[0002] As the functions of electronic devices become increasingly powerful, the amount of power required to maintain the normal operation of each function per unit time increases. Therefore, in order to solve the problem of battery life of electronic devices, how to improve the capacity and energy density of battery cells has become a new driving force for current technical personnel's research and development. Summary of the invention

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

[0004] According to a first aspect of an embodiment of the present disclosure, there is provided a negative electrode plate, comprising:

[0005] Anode current collector;

[0006] A carbon quantum dot layer, wherein the carbon quantum dot layer is formed on the surface of the negative electrode current collector;

[0007] The negative electrode silicon-containing coating layer is formed on the surface of the carbon quantum dot layer away from the negative electrode current collector.

[0008] Optionally, 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.

[0009] Optionally, the silicon-containing coating layer includes a composite layer of silicon material and graphite.

[0010] Optionally, the silicon-containing coating layer includes at least one of silicon element, silicon oxide and silicon carbide.

[0011] Optionally, the negative electrode current collector includes one of the following: 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.

[0012] According to a second aspect of an embodiment of the present disclosure, a method for manufacturing a negative electrode sheet is provided, comprising:

[0013] obtaining a negative electrode current collector;

[0014] Coating a carbon quantum dot layer on the surface of the negative electrode current collector;

[0015] A negative electrode silicon-containing coating layer is coated on the surface of the carbon quantum dot layer facing away from the negative electrode current collector.

[0016] Optionally, the coating of a carbon quantum dot layer on the surface of the negative electrode current collector comprises:

[0017] Obtaining a mixed slurry formed by mixing carbon quantum dots, an adhesive and a dispersant;

[0018] The mixed slurry is coated on the surface of the negative electrode current collector to obtain the carbon quantum dot layer.

[0019] Optionally, coating a negative electrode silicon-containing coating layer on the surface of the carbon quantum dot layer comprises:

[0020] forming a silicon-containing coating layer on the surface of the carbon quantum dot layer;

[0021] A graphite coating layer is formed on the surface of the silicon-containing coating layer.

[0022] Optionally, forming a silicon-containing coating layer on the surface of the carbon quantum dot layer comprises:

[0023] Obtaining a mixed slurry formed by mixing graphite, silicon material and adhesive;

[0024] The mixed slurry is coated on the surface of the carbon quantum dot layer to obtain the silicon-containing coating layer.

[0025] Optionally, the silicon material includes at least one of silicon element, silicon oxide and silicon carbide.

[0026] Optionally, forming a graphite coating layer on the surface of the silicon-containing coating layer comprises:

[0027] Obtaining a mixed slurry formed by mixing graphite and an adhesive;

[0028] The mixed slurry is coated on the surface of the silicon-containing coating layer to obtain the graphite coating layer.

[0029] Optionally, the adhesive includes at least one of polypropylene, polyethylene, sodium carboxymethyl cellulose, polyvinylidene fluoride and styrene-butadiene rubber.

[0030] According to a third aspect of an embodiment of the present disclosure, there is provided a battery cell, including:

[0031] Positive electrode;

[0032] A negative electrode sheet, wherein the negative electrode sheet comprises the negative electrode sheet as described in any one of the above embodiments, or the negative electrode sheet comprises the negative electrode sheet obtained by the manufacturing method as described in any one of the above embodiments;

[0033] A separator is disposed between the positive electrode sheet and the negative electrode sheet.

[0034] According to a fourth aspect of the embodiments of the present disclosure, a battery is provided, comprising a battery cell as described in any one of the embodiments above.

[0035] According to a fifth aspect of the embodiments of the present disclosure, there is provided an electronic device, comprising a battery as described in any one of the above embodiments.

[0036] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects:

[0037] It can be seen from the above embodiments that the present disclosure can utilize the characteristics of silicon materials having a higher specific capacity and a lower discharge potential than the negative electrode coating materials in traditional lithium battery technology, and can effectively improve the energy density of the battery cell equipped with the negative electrode plate. 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 can provide a larger volume change space and flexibility for the expansion of the negative electrode silicon-containing coating layer, thereby improving the mechanical properties of the negative electrode silicon-containing coating layer and reducing the risk of the negative electrode silicon-containing coating layer separating from the negative electrode current collector due to expansion during charging and discharging.

[0038] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0040] Figure 1 It is a schematic structural diagram of a negative electrode plate according to an exemplary embodiment.

[0041] Figure 2 It is a schematic structural diagram of another negative electrode plate according to an exemplary embodiment.

[0042] Figure 3 The figure is a flow chart of a method for manufacturing a negative electrode sheet according to an exemplary embodiment.

[0043] Figure 4 The figure is a flow chart of another method for manufacturing a negative electrode sheet according to an exemplary embodiment.

[0044] Figure 5 is a schematic cross-sectional view of a battery cell according to an exemplary embodiment.

[0045] Figure 6 is a schematic structural diagram of a battery according to an exemplary embodiment.

[0046] Figure 7The figure is an exploded schematic diagram of an electronic device according to an exemplary embodiment. DETAILED DESCRIPTION

[0047] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0048] The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. The singular forms of "a", "said" and "the" used in this disclosure and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0049] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present disclosure, 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. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0050] At present, with the continuous development of science and technology, the configuration functions of electronic devices are becoming increasingly powerful, and in order to meet the endurance requirements of electronic devices, higher requirements are placed on the battery capacity of electronic devices. Generally, electronic devices may include lithium batteries, and in order to increase the battery capacity of lithium batteries, R&D personnel continue to consider how to increase the capacity from aspects such as how to expand the volume of the battery compartment of the electronic device and how to reduce the space occupied by other layer structures of the lithium battery. However, these considerations may conflict with the layout of other electronic components inside the electronic device on the one hand, and on the other hand, they contribute little to the qualitative improvement of battery capacity and battery density.

[0051] Therefore, in order to be compatible with the increasingly powerful performance and endurance requirements of electronic devices, the present disclosure provides a Figure 1The negative electrode plate 100 shown may include a negative electrode current collector 1, a carbon quantum dot layer 2 and a negative electrode silicon-containing coating layer 3. The carbon quantum dot layer 2 may be formed on the surface of the negative electrode current collector 1, and the negative electrode silicon-containing coating layer 3 may 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 may be formed between the negative electrode silicon-containing coating layer 3 and the negative electrode current collector 1. Among them, the size of the carbon quantum dots included in the carbon quantum dot layer 2 may be relatively small, for example, it may be controlled to be below 10 nm. The negative electrode current collector 1 includes one of the following: 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 to this.

[0052] It can be seen from the above embodiments that the specific capacity of silicon materials is higher than that of negative electrode coating materials in traditional lithium battery technology, and the discharge potential is lower, so that the energy density of the battery cell configured with the negative electrode plate 100 can be effectively improved; 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 conductivity of the negative electrode silicon-containing coating layer 3 can be improved through the carbon quantum dot layer 2, and the interface impedance between the negative electrode current collector 1 and the negative electrode silicon-containing coating layer 3 can be reduced. Moreover, since the size of the carbon quantum dots included in the carbon quantum dot layer 2 is extremely small, a larger volume change space and flexibility performance can be provided for the expansion of the negative electrode silicon-containing coating layer 3 during the charge and discharge process, and the mechanical properties of the negative electrode silicon-containing coating layer 3 are improved, and the risk of the negative electrode silicon-containing coating layer 3 being separated from the negative electrode current collector 1 due to expansion during the charge and discharge process is reduced. Moreover, by coating the carbon quantum dot layer 2 on the negative electrode current collector 1, since the size of the carbon quantum dots in the carbon quantum dot layer 2 is extremely small, the compaction density of the negative electrode plate 100 is improved to a certain extent, which is conducive to further improving the energy density of the negative electrode plate 100.

[0053] In addition, if a silicon-containing material is used as the negative electrode coating material of the negative electrode plate 100, a large amount of lithium ions are embedded in and extracted from the negative electrode silicon-containing coating layer 3, which will cause the volume of the negative electrode silicon-containing coating layer 3 to change, and easily lead to the destruction of the silicon negative electrode active particles in the negative electrode silicon-containing coating layer 3, and the contact of the silicon negative electrode active particles becomes poor, resulting in the instability of the solid electrolyte interface film formed during the first charge and discharge. Therefore, in order to solve this problem, in the technical solution of the present disclosure, as shown in FIG. Figure 2As shown, 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 direct contact between the silicon-containing coating layer 31 and the electrolyte can be avoided by the graphite coating layer 32, reducing the reaction between the silicon-containing coating layer 31 and the electrolyte, and the graphite coating layer 32 can react with the electrolyte to form a solid electrolyte interface film. Compared with the technical solution of forming a solid electrolyte interface film by contacting the electrolyte with the silicon negative electrode, the solid electrolyte interface film formed in the present disclosure is more stable, which is conducive to improving the cycle life and rate performance of the battery configured with the negative electrode plate 100. 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 expansion of the silicon-containing coating layer 31 can be alleviated by the graphite coating layer 32 compared to the solution of using a single layer of silicon-containing coating, and since the graphite coating layer 32 has relatively large flexibility, it can play a buffering role in the diffusion of lithium ions and promote the uniform deintercalation of lithium ions, so as to further alleviate the expansion of the silicon-containing coating layer 31. Among them, the silicon-containing coating layer 31 can include a composite layer of silicon material and graphite, wherein the silicon material can include at least one material of silicon element, silicon oxide and silicon carbide.

[0054] like Figure 3 As shown, the present disclosure also provides a method for manufacturing a negative electrode sheet 100, which may include the following steps:

[0055] In step 301 , a negative electrode current collector 1 is obtained.

[0056] In this embodiment, the negative electrode current collector 1 can be 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 does not limit this.

[0057] In step 302, a carbon quantum dot layer 2 is coated on the surface of the negative electrode current collector.

[0058] In this embodiment, a slurry containing carbon quantum dots can be first obtained, and then the slurry is coated on the surface of the negative electrode current collector 1. Specifically, a mixed slurry formed by mixing carbon quantum dots with a binder, a dispersant and an additive can be obtained, and then the mixed slurry is coated on the surface of the negative electrode current collector 1 to form a carbon quantum dot layer. Among them, the binder can include at least one of polypropylene, polyethylene, sodium carboxymethyl cellulose, polyvinylidene fluoride and styrene-butadiene rubber; the dispersant can include at least one of sodium carboxymethyl cellulose, triethylhexyl phosphoric acid, sodium dodecyl sulfate, methyl amyl alcohol, cellulose derivatives and polyacrylamide. The additive can include at least one of an organic additive and an inorganic additive.

[0059] In step 303 , a negative electrode silicon-containing coating layer is formed on the surface of the carbon quantum dot layer 2 facing away from the negative electrode current collector 1 .

[0060] In this embodiment, a silicon-containing coating layer 31 can first be formed on the surface of the carbon quantum dot layer 2 facing away from the negative electrode current collector 1, and then a graphite coating layer 32 can be formed on the surface of the silicon-containing coating layer 31. The graphite coating layer 32 can alleviate the expansion of the silicon-containing coating layer 31. At the same time, a solid electrolyte interface film can be formed by the graphite coating layer 32 and the electrolyte, which is more stable than the solid electrolyte interface film formed by the reaction of the film layer of the silicon-containing material and the electrolyte.

[0061] Specifically, a mixed slurry formed by mixing graphite, silicon material, additives, dispersants and adhesives can be obtained, and then the mixed slurry is applied to the surface of the carbon quantum dot layer to obtain a silicon-containing coating layer 31, and then a mixed slurry formed by mixing graphite, adhesives, conductive agents, dispersants and additives is obtained, and the mixed slurry is applied to the surface of the silicon-containing coating layer 31 to form a graphite coating layer 32. Among them, the silicon material may include 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 carboxymethyl cellulose, polyvinylidene fluoride and styrene-butadiene rubber; the dispersant may include at least one of sodium carboxymethyl cellulose, triethylhexyl phosphoric acid, sodium dodecyl sulfate, methyl amyl alcohol, cellulose derivatives and polyacrylamide. The additive may include at least one of an organic additive and an inorganic additive. Among them, the adhesive, additive and dispersant included in the silicon-containing coating layer 31, the graphite coating layer 32 and the carbon quantum dot layer 2 may be the same or different, and the present disclosure does not limit this.

[0062] In order to elaborate on the technical solution provided by the present disclosure, Figure 4 As shown, the method for manufacturing the negative electrode plate 100 may include the following steps:

[0063] In step 401, a negative electrode current collector is obtained.

[0064] In step 402, a mixed slurry formed by mixing carbon quantum dots, a binder and a dispersant is obtained.

[0065] In step 403, the mixed slurry is coated on the surface of the negative electrode current collector to obtain the carbon quantum dot layer.

[0066] In this embodiment, the mass content of the binder 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, and the concentration of the carbon quantum dots is related to the thickness of the carbon quantum dot layer 2. The greater the thickness, the higher the concentration of the carbon quantum dots. Therefore, in actual processing, the appropriate concentration can be selected according to the thickness requirements of the carbon quantum dot layer 2, thereby determining the mass of the carbon quantum dots. In other embodiments, the mixed slurry may also include additives, and the mass content of the additives is 0%-50% of the total mass of the mixed slurry.

[0067] In step 404, a mixed slurry formed by mixing graphite, silicon material and adhesive is obtained.

[0068] In step 405, the mixed slurry is coated on the surface of the carbon quantum dot layer to obtain the silicon-containing coating layer.

[0069] 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 binder is 0.05%-5% of the total mass of the mixed slurry, and the rest is graphite material. In other embodiments, the mixed slurry may also include additives and dispersants, the mass content of the additives 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.

[0070] In step 406, a mixed slurry formed by mixing graphite and an adhesive is obtained.

[0071] In step 407, the mixed slurry is coated on the surface of the silicon-containing coating layer to obtain the graphite coating layer.

[0072] 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 binder is 0.1%-5% of the total mass of the mixed slurry. In other embodiments, the mixed slurry may also include additives, conductive agents and dispersants, 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.

[0073] Based on the embodiments of the present disclosure, Figure 5 As shown, the present disclosure also provides a battery cell 200, which may include a positive electrode sheet (not shown), a separator (not shown) and the negative electrode sheet 100 shown in any of the above embodiments, the separator is arranged between the negative electrode sheet 100 and the positive electrode sheet, and after the negative electrode sheet 100, the separator and the positive electrode sheet are stacked, they are wound to obtain Figure 5In fact, in other embodiments, the negative electrode sheet 100 can also be used to form a laminated battery cell, which is not limited in the present disclosure.

[0074] Based on the technical solution of the present disclosure, the present disclosure also provides a Figure 6 The battery 300 shown may include a battery cell 200, a shell 301 and a protection circuit board 302. The shell 301 may be used to encapsulate the battery cell 200 to protect the battery cell 200. The protection circuit board 302 may be electrically connected to the positive and negative poles of the battery cell 200, respectively, to provide safety protection for the charging and discharging of the battery 300.

[0075] Furthermore, the present disclosure provides a Figure 7 The electronic device 400 shown may include a battery compartment 401, an adhesive layer 402, and a battery 300, and the battery 300 may be adhered to the battery compartment 401 through 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 does not limit this.

[0076] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the disclosure disclosed herein. The present disclosure is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are to be considered exemplary only, and the true scope and spirit of the present disclosure are indicated by the following claims.

[0077] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A negative electrode plate, characterized in that: include: Anode current collector; A carbon quantum dot layer, wherein the carbon quantum dot layer is formed on the surface of the negative electrode current collector; A negative electrode silicon-containing coating layer, wherein the negative electrode silicon-containing coating layer is formed on a surface of the carbon quantum dot layer away from the negative electrode current collector; The carbon quantum dot layer comprises carbon quantum dots, an adhesive and a dispersant, and the thickness of the carbon quantum dot layer is positively correlated with the concentration of the carbon quantum dots; 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.

2. The negative electrode sheet according to claim 1, characterized in that: The silicon-containing coating layer includes a composite layer of silicon material and graphite.

3. The negative electrode sheet according to claim 1, characterized in that: The silicon-containing coating layer includes at least one material selected from the group consisting of silicon, silicon oxide and silicon carbide.

4. The negative electrode sheet according to claim 1, characterized in that: The negative electrode current collector includes one of the following: 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.

5. A method for manufacturing a negative electrode sheet, characterized in that: include: obtaining a negative electrode current collector; Coating a carbon quantum dot layer on the surface of the negative electrode current collector; Coating a negative electrode silicon-containing coating layer on the surface of the carbon quantum dot layer facing away from the negative electrode current collector; The step of coating a carbon quantum dot layer on the surface of the negative electrode current collector comprises: Obtaining a mixed slurry formed by mixing carbon quantum dots, an adhesive and a dispersant; Applying the mixed slurry on the surface of the negative electrode current collector to obtain the carbon quantum dot layer; The thickness of the carbon quantum dot layer is positively correlated with the concentration of the carbon quantum dots; The step of coating the negative electrode silicon-containing coating layer on the surface of the carbon quantum dot layer comprises: forming a silicon-containing coating layer on the surface of the carbon quantum dot layer; A graphite coating layer is formed on the surface of the silicon-containing coating layer.

6. The method according to claim 5, characterized in that: The step of forming a silicon-containing coating layer on the surface of the carbon quantum dot layer comprises: Obtaining a mixed slurry formed by mixing graphite, silicon material and adhesive; The mixed slurry is coated on the surface of the carbon quantum dot layer to obtain the silicon-containing coating layer.

7. The manufacturing method according to claim 6, characterized in that: The silicon material includes at least one of silicon element, silicon oxide and silicon carbide.

8. The manufacturing method according to claim 5, characterized in that: The step of forming a graphite coating layer on the surface of the silicon-containing coating layer comprises: Obtaining a mixed slurry formed by mixing graphite and an adhesive; The mixed slurry is coated on the surface of the silicon-containing coating layer to obtain the graphite coating layer.

9. The method according to claim 5, 6 or 8, characterized in that: The adhesive includes at least one of polypropylene, polyethylene, sodium carboxymethyl cellulose, polyvinylidene fluoride and styrene-butadiene rubber.

10. A battery cell, characterized in that: include: Positive electrode; A negative electrode sheet, wherein the negative electrode sheet comprises the negative electrode sheet as claimed in any one of claims 1 to 4, or the negative electrode sheet comprises the negative electrode sheet obtained by the manufacturing method as claimed in any one of claims 5 to 9; A separator is disposed between the positive electrode sheet and the negative electrode sheet.

11. A battery, characterized in that: Comprising the battery cell as claimed in claim 10.

12. An electronic device, characterized in that: Comprising the battery of claim 11.

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