CN118507854A - Preparation method of button cell, button cell and power utilization device - Google Patents

Abstract

A preparation method of a button cell, the button cell and an electric device. The preparation method of the button cell comprises the following steps: the method comprises the steps of obtaining a film layer and a first pole piece with a first pole lug, compounding the film layer on two sides of the first pole piece, and preparing a compound pole piece, wherein the film layer comprises at least one of a diaphragm and a solid electrolyte membrane; obtaining a second pole piece with a second pole lug, and alternately laminating the composite pole piece and the second pole piece to obtain a laminated battery cell; and obtaining a shell, and arranging the laminated battery core in the shell to obtain the button cell. The preparation method of the button cell can reduce the position offset between the lamination process and each lamination layer in the subsequent process, is beneficial to reducing the phenomenon of lithium precipitation, improves the cycle stability of the cell, improves the electrochemical performance and the safety performance of the button cell, and further meets the application requirements.

Description

Method for preparing button battery, button battery and power-using device

Technical Field

The present disclosure relates to the field of battery manufacturing, and in particular to a method for preparing a button-type battery, a button-type battery, and an electrical device.

Background Art

Consumer electronics are the most important downstream terminal application field of the consumer secondary battery industry. With the advancement of electronic product technology, product types and functions are becoming increasingly diversified, and the demand structure of consumer electronic products is also changing. In recent years, in particular, the demand for emerging consumer electronic products such as wireless headphones and wearable devices has gradually increased, providing new growth momentum for the consumer secondary battery industry, and the market demand for rechargeable button batteries has gradually increased.

Button batteries are important basic components of consumer electronics, and their quality and stability are crucial to the production and sales of downstream customers' products.

The methods described in this section are not necessarily methods that have been previously conceived or employed. Unless otherwise indicated, it should not be assumed that any method described in this section is considered to be prior art simply because it is included in this section. Similarly, unless otherwise indicated, the issues mentioned in this section should not be considered to have been recognized in any prior art.

Summary of the invention

The present disclosure provides a method for preparing a button-type battery, a button-type battery and an electric device.

According to the first aspect of the present disclosure, a method for preparing a button battery is provided. The preparation method comprises: obtaining a film layer and a first pole piece having a first pole ear, and compounding the film layer on both sides of the first pole piece to prepare a composite pole piece, wherein the film layer comprises at least one of a diaphragm and a solid electrolyte membrane; obtaining a second pole piece having a second pole ear, and alternately laminating the composite pole piece and the second pole piece to obtain a laminated battery core; obtaining a shell, and placing the laminated battery core in the shell to obtain a button battery.

According to another aspect of the present disclosure, a button battery is provided, which is prepared according to the preparation method of the first aspect.

According to yet another aspect of the present disclosure, an electric device is provided, comprising the button battery of the other aspect.

These and other aspects of the disclosure will be apparent from and elucidated with reference to the embodiments described hereinafter.

The preparation method of the button battery provided in the embodiment of the present application can reduce the position deviation between each layer in the stacking process and subsequent processes, which is beneficial to reduce lithium plating, improve the cycle stability of the battery, improve the electrochemical performance and safety performance of the button battery, and further meet application requirements.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details, features and advantages of the present disclosure are disclosed in the following description of exemplary embodiments in conjunction with the accompanying drawings, in which:

FIG. 1 is a flow chart illustrating a method for preparing a button cell according to an exemplary embodiment;

FIG. 2 is a schematic diagram illustrating a first pole piece according to an exemplary embodiment;

FIG3 is a schematic diagram illustrating a second pole piece according to an exemplary embodiment;

FIG4 is a schematic diagram illustrating a composite pole piece according to an exemplary embodiment;

FIG5 is a flow chart illustrating a method for preparing a button cell according to another exemplary embodiment;

FIG6 is a schematic diagram illustrating a laminated battery cell according to an exemplary embodiment, (A) is a top view, and (B) is a side view;

7 is a flow chart illustrating a method for preparing a button cell according to an exemplary embodiment;

FIG. 8 is a schematic diagram illustrating a battery cell to be assembled according to an exemplary embodiment.

DETAILED DESCRIPTION

The following embodiments of the technical solution of the present application will be described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of the present application, the term "and/or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and/or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character "/" in this article generally indicates that the associated objects before and after are in an "or" relationship.

In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

It should be understood that in this specification, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships or dimensions that are based on the orientations or positional relationships or dimensions shown in the accompanying drawings, and these terms are used only for the convenience of description and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present application.

In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it 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 internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

In the prior art, button batteries are mainly composed of a positive electrode shell, a negative electrode shell, a positive electrode sheet, a negative electrode sheet, an electrolyte, etc. During the assembly process, the positive electrode sheet, the negative electrode sheet, and the diaphragm are first punched into small discs and then stacked. In order to improve the safety of the battery, the outer diameters of the positive electrode sheet, the negative electrode sheet, and the diaphragm are generally different, but this can easily cause relative position offsets between the layers during the stacking process. Even if there are fixtures to assist in positioning during the stacking process, the next process after stacking is prone to offset. As the use time increases, lithium deposition will occur at the offset position, resulting in a decrease in battery performance or safety issues.

In view of this, an embodiment of the present disclosure provides a method for preparing a button-type battery. The exemplary embodiments of the present disclosure are described in detail below in conjunction with the accompanying drawings.

Fig. 1 is a schematic diagram illustrating a method 100 for preparing a button cell according to an exemplary embodiment. As shown in Fig. 1, the method 100 for preparing a button cell includes: step S110, obtaining a film layer and a first pole piece having a first pole ear, and compounding the film layer on both sides of the first pole piece to prepare a compound pole piece, wherein the film layer includes at least one of a diaphragm and a solid electrolyte membrane; step S120, obtaining a second pole piece having a second pole ear, and alternately laminating the compound pole piece and the second pole piece to obtain a laminated battery cell; step S130, obtaining a shell, and placing the laminated battery cell in the shell to obtain a button cell.

2-3 respectively illustrate schematic diagrams of a first pole piece and a second pole piece according to exemplary embodiments. In some embodiments, as shown in FIG2 , the first pole piece 200 includes a first active material layer 210 and a first pole tab 220. In some embodiments, as shown in FIG3 , the second pole piece 300 includes a second active material layer 310 and a second pole tab 320.

FIG4 illustrates a schematic diagram of a composite pole piece according to an exemplary embodiment. In some embodiments, as shown in FIG4 , the composite pole piece 400 includes a first pole piece 200 and a film layer 410 disposed on both sides of a first active material layer 210 of the first pole piece 200, the film layer 410 includes at least one of a diaphragm and a solid electrolyte membrane, and the projection of the first active material layer 210 in the direction of the film layer 410 falls within the area range of the film layer 410.

In some embodiments, the separator includes a polymer film or a composite film with a polymer disposed on a surface.

In some embodiments, the separator includes a polymer film, such as a polyethylene (PE) separator, a polypropylene (PP) separator, and a PE and PP composite multilayer microporous membrane. In some embodiments, the separator includes a composite membrane, and a polymer such as polyvinylidene fluoride PVDF is disposed on the surface of the composite membrane.

With the help of the polymer in the diaphragm, the diaphragm can form a composite pole piece with the first pole piece under the action of temperature and/or pressure.

In some embodiments, a solid electrolyte membrane includes a base membrane and a bonding portion disposed on at least one side of the base membrane.

In some embodiments, the base film includes a solid electrolyte. In some embodiments, the bonding portion includes a binder. In some embodiments, the bonding portion includes a binder and a solid electrolyte. In some embodiments, the binder includes polyvinylidene fluoride, an acrylic polymer.

The bonding portion can not only play the role of bonding the solid electrolyte membrane and the first pole piece, but also play the role of a diaphragm.

The preparation method 100 can reduce the positional deviation between the layers in the lamination process and subsequent processes, and improve the electrochemical performance and safety performance of the button battery.

In some embodiments, the first pole tab 220 and/or the second pole tab 320 are shaped pole tabs. In some embodiments, as shown in FIG2 , the first pole tab 220 is a shaped pole tab. A shaped pole tab refers to a pole tab with an irregular shape, and a shaped pole tab is usually a polygonal pole tab, including a non-regular polygon or a regular polygon with at least five sides.

The special-shaped tabs help to improve the accuracy of the position of each layer during stacking, reduce the position offset between each layer, and further improve the electrochemical performance and safety performance of the battery.

In some embodiments, the first pole piece is a positive pole piece, and the second pole piece is a negative pole piece, which can be lithium metal or its alloy.

In an example, the positive electrode sheet may include a positive electrode current collector and a positive electrode material disposed on the positive electrode current collector. The positive electrode current collector may be an aluminum foil. The positive electrode material may include active materials such as lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, sulfide, or a ternary (nickel, cobalt, manganese) polymer. In addition, the positive electrode material may also include a conductive agent and a binder, the binder may include polyvinylidene fluoride, for example, and the conductive agent may include nano carbon black, for example. The positive electrode sheet may be produced by stirring a slurry of the positive electrode material, coating it on the positive electrode current collector, and drying it.

Lithium metal negative electrode sheets are different from negative electrode sheets made of other materials (such as graphite, nitride, titanium-based materials, etc.). They have the advantages of low density (lithium density is relatively low, only 0.534g/cm3) and high capacity (the gram capacity of metallic lithium is as high as 3860mA·h/g, which is ten times that of graphite negative electrode). Therefore, using lithium metal and its alloys as negative electrode materials can significantly improve the energy density of the battery. In addition, the electrochemical potential of lithium metal is relatively low, and it can be matched with a wider range of positive electrode materials (for example, the positive electrode material can contain lithium or not).

FIG5 is a flow chart illustrating a method 500 for preparing a button cell according to an exemplary embodiment. As shown in FIG5 , the method 500 includes steps S510 to S540. Step S510 is similar to step S110 described with respect to FIG1 , and step S540 is similar to step S130 described with respect to FIG1 , and for the sake of brevity, they are not described again.

According to some embodiments, as shown in FIG. 5 , step S120 described in FIG. 1 may further include: step S520, stacking the composite pole piece and the second pole piece alternately in a manner such that the first pole ear and the second pole ear extend in opposite directions from the side of the diaphragm and then hot-pressing them; step S530, shaping the diaphragm to obtain a stacked battery cell.

In some embodiments, the stacked battery cell 600 is as shown in FIG6 , wherein the projection of the first active material layer 210 in the direction of the membrane layer 410 falls within the area of the second active material layer 310 , the projection of the second active material layer 310 in the direction of the membrane layer 410 falls within the area of the membrane layer 410 , and the first pole ear 220 and the second pole ear 320 extend in opposite directions from the side of the diaphragm 410 .

In some embodiments, step S530 of shaping the diaphragm includes: using laser thermal cutting or resistance wire thermal cutting to cut off the periphery of the diaphragm so that the area of the diaphragm is slightly larger than the area of the second active material layer 310, thereby meeting safety requirements and reducing weight.

The above method has high cutting efficiency and accurate cutting, which can improve product accuracy and production efficiency.

FIG7 is a flow chart illustrating a method 700 for preparing a button cell according to an exemplary embodiment. As shown in FIG7 , the method 700 includes steps S710 to S750. Step S710 is similar to step S110 described with respect to FIG1 , and step S720 is similar to step S120 described with respect to FIG1 , and for the sake of brevity, they are not described again.

According to some embodiments, as shown in FIG. 7 , step S130 described in FIG. 1 may further include: step S730, gathering a plurality of first pole tabs in the stacked battery cell at a first end face adjacent to the stacked battery cell, and welding them into a first pole tab group; gathering a plurality of second pole tabs in the stacked battery cell at a second end face side adjacent to the first end face opposite to the stacked battery cell, and welding them into a second pole tab group, to obtain a battery cell to be assembled; step S740, shaping the first pole tab group and/or the second pole tab group and respectively connecting them to opposite sides of the shell; step S750, encapsulating the battery cell to be assembled in the shell, and obtaining a button battery.

The above-mentioned assembly method helps to reduce the internal resistance of the button battery and improve its electrochemical performance.

In some embodiments, the tabs are formed into tab groups by ultrasonic welding.

In some embodiments, the structure of the battery cell 800 to be assembled is shown in FIG8 , and the first tab group 810 and the second tab group 820 are respectively disposed on the first end surface and the second end surface of the battery cell to be assembled 800. It can be understood that the first end surface can be the top surface or the bottom surface, and correspondingly, the second end surface can be the bottom surface or the top surface.

In some embodiments, step S740 of shaping the first pole lug group and/or the second pole lug group and connecting them to opposite sides of the shell includes: after cutting and shaping the first pole lug group and/or the second pole lug group, welding the first pole lug group and/or the second pole lug group to opposite sides of the shell through connecting plates, optionally, the connecting plates include nickel-plated copper plates or nickel plates, the thickness of the connecting plates is 0.1-0.5 mm, the shell includes a steel shell, and the welding includes resistance welding or laser welding.

In some embodiments, cutting and shaping the first electrode tab group and/or the second electrode tab group includes shaping special-shaped electrode tabs to achieve weight reduction.

The use of steel shell can improve the energy density of the battery and reduce the expansion rate of the battery. Nickel-plated copper sheet or nickel sheet as a connecting sheet can improve the stability of welding with the steel shell and improve the service life of the button battery.

In some embodiments, the housing includes a first housing portion and a second housing portion, which can accommodate the battery cell to be assembled after being assembled together. In some embodiments, the first tab group is welded to the first housing portion, and the second tab group is welded to the second housing portion.

In some embodiments, step S750B of encapsulating the battery cell to be assembled in the shell to obtain a button battery includes: placing the battery cell to be assembled in the shell, injecting electrolyte, and pressing and encapsulating the shell to obtain a button battery.

For button batteries using solid electrolytes, the electrolyte content is trace or trace, which can reduce the probability of leakage and further improve the safety of the button batteries.

In some embodiments, the injecting of the electrolyte is performed in a low dew point environment, and the dew point range is optionally -40°C to 80°C.

Dew point refers to the temperature at which the gaseous water contained in the environment reaches saturation and condenses into liquid water under a fixed air pressure. In some embodiments, the dew point can be selected to be -45°C, -50°C, -60°C, -70°C, -80°C, or any range of values therebetween. Injecting electrolyte in a low dew point environment can reduce the volatilization of solvents in the electrolyte and improve the stability of the electrochemical performance of the battery.

A second aspect of the present application provides a button-type battery prepared according to the preparation method of any embodiment.

A third aspect of the present application provides an electrical device, comprising a button battery of any embodiment.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims (10)

1. A method for preparing a button battery, characterized in that the preparation method comprises: Obtaining a film layer and a first pole piece having a first pole ear, and compounding the film layer on both sides of the first pole piece to prepare a compound pole piece, wherein the film layer includes at least one of a diaphragm and a solid electrolyte membrane; Obtaining a second pole piece having a second pole ear, and alternately stacking the composite pole piece and the second pole piece to obtain a stacked battery cell; Obtain a shell, set the laminated battery core in the shell, and obtain a button battery. 2. The preparation method according to claim 1, characterized in that the composite pole piece and the second pole piece are alternately stacked to obtain a stacked battery cell comprising: The composite pole piece and the second pole piece are alternately laminated and hot-pressed in a manner that the first pole ear and the second pole ear extend in opposite directions from the side of the diaphragm; The diaphragm is shaped to obtain a laminated battery cell. 3. The preparation method according to claim 2, characterized in that the shaping of the diaphragm comprises: Use laser thermal cutting or resistance wire thermal cutting to cut off the periphery of the diaphragm. 4. The preparation method according to claim 1, characterized in that the step of arranging the laminated battery cell in the housing to obtain a button-type battery comprises: Gathering a plurality of first pole tabs in the laminated battery core at a first end face adjacent to the laminated battery core and welding them into a first pole tab group; gathering a plurality of second pole tabs in the laminated battery core at a second end face side adjacent to the first end face opposite to the laminated battery core and welding them into a second pole tab group to obtain a battery core to be assembled; After shaping, the first electrode tab group and/or the second electrode tab group are respectively connected to opposite sides of the housing; The battery cell to be assembled is encapsulated in the housing to obtain a button battery. 5. The preparation method according to claim 4, characterized in that the first electrode tab group and/or the second electrode tab group are shaped and connected to opposite sides of the housing respectively, comprising: After cutting and shaping the first pole lug group and/or the second pole lug group, they are respectively welded to the opposite sides of the shell through connecting plates. Optionally, the connecting plates include nickel-plated copper plates or nickel plates, the thickness of the connecting plates is 0.1-0.5 mm, the shell includes a steel shell, and the welding includes resistance welding or laser welding. 6. The preparation method according to claim 5, characterized in that the step of encapsulating the battery cell to be assembled in the housing to obtain a button-type battery comprises: The battery cell to be assembled is placed in the shell, and then an electrolyte is injected. The shell is pressed and sealed to obtain a button battery. 7. The preparation method according to claim 1, characterized in that: The first pole tab and/or the second pole tab are/is a special-shaped pole tab. 8. The preparation method according to claim 1, characterized in that: The first pole piece is a positive pole piece, and the second pole piece is a negative pole piece, which can be made of lithium metal or its alloy. 9. A button battery, characterized in that it is prepared by the preparation method according to any one of claims 1 to 8. 10. An electrical device, characterized in that it comprises the button battery according to claim 9.