CN117855593A - Solid-state battery, method for producing same, and power consumption device - Google Patents

Abstract

The present disclosure provides a solid-state battery, a method of manufacturing the same, and an electric device. The solid-state battery includes: a composite pole piece, a negative pole piece and electrolyte; the composite pole piece comprises a positive pole piece and a solid electrolyte membrane, and the solid electrolyte membrane is arranged on at least one side of the positive pole piece; the negative pole piece is arranged at one side of the solid electrolyte membrane far away from the positive pole piece, and the electrolyte is mainly arranged at the side of the composite pole piece. The solid-state battery has better electrochemical performance and safety performance.

Description

Solid-state battery, preparation method thereof and power-using device

Technical Field

The present disclosure relates to the field of battery manufacturing, and in particular to a solid-state battery and an electrical device.

Background technique

Due to the demand for energy conservation and emission reduction, batteries are being used more and more widely. Batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of battery application areas, its market demand is also constantly expanding.

Lithium batteries are now more and more widely used due to their high energy density, long charging life, low self-discharge, etc. How to effectively improve the safety of batteries is a technical problem that needs to be solved urgently in this field.

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 solid-state battery to improve the safety performance of the battery.

According to one aspect of the present disclosure, a solid-state battery is provided, comprising: a composite electrode sheet, a negative electrode sheet and an electrolyte, wherein the composite electrode sheet comprises a positive electrode sheet and a solid electrolyte membrane, wherein the solid electrolyte membrane is arranged on at least one side of the positive electrode sheet; the negative electrode sheet is arranged on a side of the solid electrolyte membrane away from the positive electrode sheet, and the electrolyte is mainly arranged on the composite electrode sheet side.

According to another aspect of the present disclosure, a method for preparing a solid-state battery is provided, the method comprising: providing a composite electrode sheet comprising a positive electrode sheet and a solid electrolyte membrane; providing an electrolyte in the composite electrode sheet to prepare a liquid-immersed electrode sheet; and stacking the liquid-immersed electrode sheet and the negative electrode sheet to obtain a solid-state battery.

According to another aspect of the present disclosure, there is provided an electrical device, which includes the above-mentioned solid-state battery or the solid-state battery prepared by the above-mentioned preparation method.

The beneficial technical effect of the present disclosure is that the solid-state battery reduces the probability of contact between the electrolyte and the negative electrode plate by mainly arranging the electrolyte on the composite electrode plate side, reduces the possibility of side reactions, and can effectively improve the electrochemical performance and safety of the battery.

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

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 schematic diagram of a structure of a solid-state battery according to an exemplary embodiment;

FIG. 2 is a flow chart of a method of manufacturing a solid-state battery according to an exemplary embodiment.

Detailed ways

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.

A solid-state battery refers to a battery that uses solid-state electrolytes to completely or partially replace the electrolyte. The use of solid-state electrolytes allows high-capacity, high-activity negative electrode materials such as lithium metal to be used in secondary batteries. Therefore, solid-state batteries often have high energy density and safety performance. However, the overall conductivity of solid-state electrolytes is relatively low, which makes the internal resistance of solid-state batteries relatively large and the overall rate performance is relatively low. In order to compensate for this defect, a certain amount of liquid electrolyte is often retained in solid-state batteries. However, the contact between the liquid electrolyte and the negative electrode often produces more side reactions, reducing the electrochemical performance and safety performance of the battery.

In view of this, embodiments of the present disclosure provide a solid-state battery, a method for manufacturing the same, and an electrical device.

FIG. 1 is a structural diagram of a solid-state battery 100 according to an exemplary embodiment.

As shown in Figure 1, the solid-state battery 100 includes: a composite electrode sheet 110, a negative electrode sheet 120 and an electrolyte (not shown), the composite electrode sheet 110 includes a positive electrode sheet 111 and a solid electrolyte membrane 112, the solid electrolyte membrane 112 is arranged on at least one side of the positive electrode sheet 111, the negative electrode sheet 120 is arranged on the side of the solid electrolyte membrane 112 away from the positive electrode sheet 111, and the electrolyte, the electrolyte is mainly arranged on the side of the composite electrode sheet 110.

In some embodiments, the solid electrolyte membrane 112 plays the role of active ion transmission and electrochemical reaction connecting the positive electrode plate 111 and the negative electrode plate 120 , and also plays the role of a battery separator to prevent direct contact between the positive electrode plate 111 and the negative electrode plate 120 .

In some embodiments, the electrolyte is mainly disposed on the composite electrode sheet 110 side, which means that the solvent in the electrolyte is mainly concentrated in the positive electrode sheet 111 or in the solid electrolyte membrane 112 or between the two.

This solid-state battery reduces the probability of contact between the electrolyte and the negative electrode plate by mainly placing the electrolyte on the composite electrode side, reduces the possibility of side reactions, and can effectively improve the electrochemical performance and safety of the battery.

In some embodiments, as shown in FIG1 , in the solid-state battery 110, the distance between any edge of the solid-state electrolyte membrane 112 and the central axis A of the solid-state battery is L1, the distance between any edge of the positive electrode plate 111 and the central axis A of the solid-state battery is L2, and the distance between any edge of the negative electrode plate 120 and the central axis A of the solid-state battery is L3, and L1>L3>L2.

The above settings can further improve the safety of solid-state batteries.

In some embodiments, the negative electrode plate includes lithium metal and its alloys.

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 metal 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 batteries. In addition, lithium metal has a low electrochemical potential and can be used with a wider range of positive electrode materials (for example, the positive electrode material can contain lithium or not).

In some embodiments, the solid electrolyte membrane includes a base membrane and a first bonding portion disposed on the negative electrode sheet side of the base membrane.

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

The first bonding portion can not only bond the solid electrolyte membrane and the negative electrode plate, but also block the solvent in the electrolyte from infiltrating the negative electrode plate, so that the solid electrolyte membrane has a higher density and can reduce the diffusion of the solvent in the electrolyte to the negative electrode plate.

In some embodiments, the solid electrolyte membrane further includes a second bonding portion disposed on the positive electrode tab side of the base membrane.

In some embodiments, the second bonding portion includes a bonding agent. In some embodiments, the second bonding portion includes a bonding agent and a solid electrolyte. In some embodiments, the second bonding portion is dispersedly arranged on the positive electrode sheet side of the base film in a dot or strip shape. The second bonding portion can realize a simple composite of the positive electrode sheet and the solid electrolyte membrane, thereby improving the preparation efficiency of the composite electrode sheet.

In some embodiments, the second bonding portion is disposed at the side edge of the base film. The above arrangement achieves a packaging effect on the electrolyte and reduces the overflow of the electrolyte.

The second bonding part can not only bond the solid electrolyte membrane and the positive electrode sheet, but also effectively reduce the weight of the battery through reasonable design.

In some embodiments, the area coverage of the first bonding portion on the base film is greater than the area coverage of the second bonding portion on the base film.

In some embodiments, based on the total area of the base film, the area coverage of the first bonding portion on the base film is 70%-90%. In some embodiments, based on the total area of the base film, the area coverage of the first bonding portion on the base film can be 70%, 75%, 80%, 85%, 90% or any range therebetween.

In some embodiments, based on the total area of the base film, the area coverage of the second bonding portion on the base film is 20%-30%. In some embodiments, based on the total area of the base film, the area coverage of the first bonding portion on the base film can be 20%, 25%, 30% or any range therebetween.

The area coverage of the first bonding portion on the base film is a ratio of the projected area of the first bonding portion on the base film divided by the area of the base film.

In some embodiments, in the solid-state battery, the unit mass of the electrolyte is 0.1-2.5 g/Ah.

In some embodiments, in a solid-state battery, the unit mass of the electrolyte can be selected to be 0.1 g/Ah, 0.5 g/Ah, 1 g/Ah, 1.5 g/Ah, 2 g/Ah, 2.5 g/Ah, or any range of values therebetween.

In some embodiments, based on the total mass of the solid-state battery, the mass content of the electrolyte in the solid-state battery is less than or equal to 20%, optionally less than or equal to 10%, and optionally less than or equal to 5%.

In some embodiments, based on the total mass of the solid-state battery, the mass content of the electrolyte in the solid-state battery can be selected to be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% or any numerical range therebetween.

The solid-state battery contains a small amount of electrolyte, which can effectively reduce the infiltration of the solvent in the electrolyte into the negative electrode plate, so that the electrolyte is mainly concentrated on the composite electrode side, reducing the side reaction between the electrolyte and the negative electrode plate, and improving the electrochemical performance and safety of the battery.

In some embodiments, the solid electrolyte membrane includes a solid electrolyte including one or more of a polymer electrolyte, an oxide electrolyte, a sulfide electrolyte, and a halide electrolyte.

Polymer electrolytes include all-solid polymer electrolytes and gel polymer electrolytes. All-solid polymer electrolytes are obtained by dissolving lithium salts in high molecular polymer matrix materials. They are a type of complex formed by coordination between lithium salts and high molecular polymers. With the movement of organic polymer segments in the amorphous region of the polymer matrix in the polymer electrolyte, lithium ions and electron-donating groups on the polymer matrix units continuously undergo "coordination-decoordination", thereby achieving the migration of lithium ions. Gel polymer electrolytes are mainly composed of polymer matrix, plasticizer and lithium salt, which form a polymer network with a suitable microstructure through mutual dissolution.

In some embodiments, the polymer in the polymer electrolyte includes polyethylene oxide, polymethyl methacrylate, polyacrylonitrile, polyvinylidene fluoride-hexafluoropropylene copolymer, polypropylene oxide. In some embodiments, the lithium salt in the polymer electrolyte includes one or more of LiClO ₄ , LiPF ₆ , LiCF ₃ SO ₃ , LiN(CF ₃ SO ₂ ) ₂ .

In some embodiments, the sulfide electrolyte includes lithium sulfide. The sulfide electrolyte includes, but is not limited to, Li ₂ S—SiS ₂ , Li ₂ SB ₂ S ₃ , Li ₂ SP ₂ S ₅ , and the like.

In some embodiments, the oxide electrolyte includes lithium oxide. The oxide electrolyte includes, but is not limited to, Li ₂ OB ₂ O ₃ —P ₂ O ₅ , Li ₂ O-SEO ₂ —B ₂ O ₃ , Li ₂ OB ₂ O _{3 —SiO 2} and the like.

In some embodiments, the positive electrode sheet includes a positive electrode active material, and the positive electrode active material includes one or more of a lithium-containing phosphate and a lithium transition metal oxide.

In some embodiments, the lithium transition metal oxide includes lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide and their respective doping modified materials or coating modified materials. The lithium-containing phosphate includes lithium iron phosphate, lithium manganese phosphate, lithium manganese iron phosphate and their respective doping modified materials or coating modified materials.

FIG. 2 is a schematic diagram of a method of manufacturing a solid-state battery according to an exemplary embodiment.

As shown in FIG2 , a method 200 for manufacturing a solid-state battery includes: step S210, providing a composite electrode including a positive electrode and a solid electrolyte membrane; step S220, providing an electrolyte in the composite electrode to prepare a liquid-immersed electrode; step S230, stacking the liquid-immersed electrode and the negative electrode to obtain a solid-state battery.

First, an electrolyte is provided in a composite electrode sheet including a positive electrode sheet and a solid electrolyte membrane, and then the composite electrode sheet is laminated with a negative electrode sheet, so that the electrolyte is concentrated in the positive electrode sheet and the solid electrolyte membrane, and a large external force is required to make the solvent in the electrolyte pass through the solid electrolyte membrane and achieve direct contact with the negative electrode sheet. The above preparation method can reduce the probability of direct contact between the solvent in the electrolyte and the negative electrode sheet, and improve the electrochemical performance and safety performance of the battery.

In some embodiments, step S210 specifically includes hot pressing the positive electrode sheet and the solid electrolyte membrane to prepare a composite electrode sheet.

In some embodiments, before step S230, at least one of a tool and a laser is used to cut the lithium metal material to obtain the negative electrode sheet.

It is understood that the cutter can be in any form, such as an alloy cutter, a contoured cutter die, etc. In the example, the cutter is disposed at the edge of the die to punch out a negative electrode sheet of a specified size and shape.

In some embodiments, the surface of the cutter comprises ceramic or polymer.

It is understandable that the ceramic or polymer can be provided on the surface of the tool in the form of a coating, or it can be directly integrally formed. The surface of the tool includes ceramic or polymer, and in particular, the above materials are provided on the surface of the blade, so that lithium metal materials can be smoothly cut, the tool is not prone to sticking, and the cut section is smoother, and the burrs on the cutting surface can be controlled at the micron level. In addition, since ceramic or polymer has good wear resistance, the service life of the cutting tool can be extended. In the example, the blade surface of the tool includes ceramic or polymer. In the example, the tool includes a metal blade body and a ceramic or polymer blade.

In some embodiments, the ceramic is selected from the group consisting of zirconium oxide, zinc oxide, titanium oxide, mica, magnesium oxide, silicon nitride, boron nitride, aluminum nitride, titanium nitride, and glass ceramics.

In some embodiments, the polymer comprises polytetrafluoroethylene.

In some embodiments, laser cutting of the lithium metal negative electrode sheet is performed.

Since the single substance corresponding to lithium metal is a silvery-white soft metal with the lowest density, contact cutting methods such as knives are prone to physical problems such as lithium metal sticking to the knife and cutting adhesion. Laser cutting can effectively solve this problem. It uses a high-power density laser beam to irradiate lithium metal materials, so that lithium metal is quickly heated to the vaporization temperature and evaporates to form holes. As the laser source moves relative to the lithium metal material, the holes are continuously formed with a very narrow width, such as a slit of about 0.1mm, completing high-quality cutting of lithium metal materials.

In some embodiments, the laser can be selected as a red laser, a violet laser, or a green laser.

In some embodiments, the speed of laser cutting is 5 m/min-100 m/min.

In some embodiments, the speed of laser cutting can be selected as 5m/min, 10m/min, 20m/min, 30m/min, 40m/min, 50m/min, 60m/min, 70m/min, 80m/min, 90m/min, 100m/min or any range therebetween.

The laser cutting speed within the above range can not only reduce cutting burrs, but also reduce the probability of lithium metal materials generating molten beads and deteriorating electrical performance during the heating and cooling process, thereby improving the molding quality of the negative electrode sheet.

In some embodiments, the preparation environment of the solid-state battery is an inert atmosphere or air with a dew point of -45°C to -90°C.

The inert atmosphere can be selected from one or more of nitrogen, argon, helium, and neon.

Dew point refers to the temperature that needs to be lowered to saturate the gaseous water contained in the air and condense into liquid water under a fixed air pressure. In some embodiments, the dew point can be selected as -45°C, -50°C, -60°C, -70°C, -80°C, -90°C, or any range of values therebetween. It is understandable that the preparation of solid-state batteries can be carried out in a separate inert atmosphere or low dew point air environment, or in a mixed environment of inert atmosphere and low dew point air. Injecting electrolyte and subsequent assembly in a low dew point environment or inert atmosphere can reduce the volatilization of solvents in the electrolyte and improve the stability of the battery's electrochemical performance.

A third aspect of the present application provides an electrical device, comprising a solid-state battery of any embodiment or a solid-state battery prepared by a preparation method 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 (11)

1. A solid-state battery, characterized in that the solid-state battery comprises:

the composite pole piece comprises a positive pole piece and a solid electrolyte membrane, the solid electrolyte membrane is arranged on at least one side of the positive pole piece,

a negative electrode plate arranged on one side of the solid electrolyte membrane far away from the positive electrode plate, and

and the electrolyte is mainly arranged on the side of the composite pole piece.

2. The solid state battery of claim 1, wherein the negative electrode tab comprises lithium metal and alloys thereof.

3. The solid state battery according to claim 1, wherein the solid state electrolyte membrane includes a base membrane and a first adhesive portion provided on a negative electrode tab side of the base membrane.

4. The solid state battery according to claim 3, wherein the solid state electrolyte membrane further comprises a second adhesive portion provided on the positive electrode sheet side of the base film.

5. The solid state battery of claim 4, wherein an area coverage of the first bond on the base film is greater than an area coverage of the second bond on the base film.

6. The solid-state battery according to claim 1, wherein in the solid-state battery, the electrolyte has a unit mass of 0.1 to 2.5g/Ah.

7. The solid state battery of claim 1, wherein the solid state electrolyte membrane comprises a solid state electrolyte comprising one or more of a polymer electrolyte, an oxide electrolyte, a sulfide electrolyte, a halide electrolyte.

8. The solid state battery of claim 1, wherein the positive electrode sheet comprises a positive electrode active material comprising one or more of a lithium-containing phosphate, a lithium transition metal oxide.

9. A method of manufacturing a solid-state battery, the method comprising:

providing a composite pole piece comprising a positive pole piece and a solid electrolyte membrane;

providing electrolyte in the composite pole piece to prepare an immersion pole piece;

and laminating the immersion pole piece and the negative pole piece to obtain the solid-state battery.

10. The manufacturing method according to claim 9, wherein the manufacturing environment of the solid-state battery is an inert atmosphere or air having a dew point of-45 ℃ to-90 ℃.

11. An electric device, characterized in that the electric device comprises the solid-state battery according to any one of claims 1 to 8 or the solid-state battery produced by the production method according to claim 9 or 10.