Solid-state battery current collector and manufacturing method, solid-state battery and manufacturing method

Abstract

The application provides a solid battery current collector and a manufacturing method, a solid battery and a manufacturing method, and relates to the technical field of solid batteries, wherein the solid battery current collector comprises a mixed powder layer and an electrode active material layer, the mixed powder layer comprises metal particles and binder particles, the metal particles are bridged with each other in the mixed powder layer to form a continuous metal particle layer, the mixed powder layer is connected to the electrode active material layer through dry one-time forming, and the electrode active material layer is a positive electrode active material layer or a negative electrode active material layer. The technical scheme solves the technical problems that the interface processing mode of the solid battery in the prior art is complex and short circuit is prone to occur between the current collector layers.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid-state batteries, in particular to a solid-state battery current collector and manufacturing method, a solid-state battery and manufacturing method. BACKGROUND

[0002] A solid-state battery is a kind of secondary battery based on solid-state electrolyte and both the positive and negative electrodes are solid materials. The solid-state electrolyte plays a role in conducting ions and isolating electrons. During charging, ions migrate from the positive electrode material lattice to the negative electrode, and electrons are transmitted to the negative electrode through the external circuit, and combine with the ions at the negative electrode to form atoms, or are embedded in the negative electrode material. The solid-state electrolyte is used to build an ion conduction path and prevent direct contact between electrodes to cause short circuit. The existing solid-state battery preparation technology is similar to that of liquid electrolyte or semi-solid electrolyte lithium battery, which is prepared by bonding the positive and negative active materials on the surface of a copper foil or aluminum foil current collector through an adhesive layer, and then laminating with a solid-state electrolyte. This method can easily mass-produce regular-shaped solid-state lithium batteries, such as cylindrical wound batteries, square wound batteries, and square stacked batteries.

[0003] The positive electrode of a solid-state battery is composed of a positive active material and a positive current collector, and the negative electrode is composed of a negative active material and a negative current collector. The function of the current collector is mainly to collect and output the current generated by the battery active material or input the current to the active material. The positive and negative current collectors should have sufficient contact with the positive and negative active materials to form good interface properties and have good electrical conductivity. The electrical conductivity and bonding ability between the positive and negative materials and the current collector affect the performance and service life of the solid-state battery.

[0004] In the process of implementing the technical solutions of the present application, it is found that the prior art has the following defects:

[0005] 1. When using copper foil or aluminum foil as the current collector, the surface thereof needs to be specially treated to achieve a certain roughness to avoid the smooth surface of the copper foil or aluminum foil being unfavorable for the adhesive to bond the positive and negative active materials. For example, the commonly used negative copper foil has single-sided hair, double-sided hair, and surface roughening to improve the bonding performance of the negative active material and the negative current collector.

[0006] 2. Copper foil or aluminum foil is a continuous metal film with uniform thickness. When the battery is punctured, impacted, or extruded, the sharp edges generated by the local damage of the copper foil or aluminum foil can easily penetrate the electrolyte layer, and then cause short circuits between the active material layers, the current collector layers, or the active material layers and the current collector layers, forming a large short-circuit current and causing a rapid temperature rise in the local area, and even causing thermal runaway. SUMMARY

[0007] The present invention aims to provide a solid-state battery current collector and manufacturing method, as well as a solid-state battery and manufacturing method, to address the technical issues of complex interface processing methods and the susceptibility to short circuits between current collector layers in existing solid-state batteries. The various technical effects achieved by the preferred technical solutions provided by the present invention are detailed below.

[0008] To achieve the above-mentioned objectives, on the one hand, the present invention provides a solid battery current collector, comprising a mixed powder layer and an electrode active material layer, wherein the mixed powder layer comprises metal particles and binder particles, and the metal particles are bridged with each other in the mixed powder layer to form a continuous metal particle layer, and the mixed powder layer is connected to the electrode active material layer by dry one-time molding, and the electrode active material layer is a positive electrode active material layer or a negative electrode active material layer.

[0009] In another aspect, the present invention provides a method for manufacturing a solid battery current collector, which is used to manufacture the solid battery current collector as described above, comprising the following steps:

[0010] mixing metal particles and binder particles in a dry powder state to form a mixed powder;

[0011] forming a mixed powder layer on the electrode active material layer by coating, spraying or doctor blade coating the mixed powder;

[0012] A specific pressure and a specific current are applied between the mixed powder layer and the electrode active material layer, and the solid battery current collector is obtained after treatment for a specific time.

[0013] On the other hand, the present invention provides a solid battery, comprising the solid battery current collector as described above, wherein the solid battery current collector comprises a positive electrode current collector I and a negative electrode current collector I, and the solid battery further comprises a solid electrolyte layer I, wherein the positive electrode current collector I, the solid electrolyte layer and the negative electrode current collector I are arranged in sequence.

[0014] In another aspect, the present invention provides a method for manufacturing a solid battery, for manufacturing the solid battery as described above, comprising the following steps:

[0015] mixing metal particles and binder particles in a dry powder state to form a mixed powder;

[0016] forming a mixed powder layer I on the negative electrode active material layer I by coating, spraying or doctor blade coating the mixed powder;

[0017] Applying a specific pressure and a specific current for a specific time between the mixed powder layer I and the negative electrode active material layer I to form a negative electrode current collector I;

[0018] The solid electrolyte layer I and the positive active material layer I are sequentially stacked on the negative active material layer I side, and then the mixed powder layer II is formed on the positive active material layer I by coating, spraying or doctor blading;

[0019] A specific pressure and a specific current are applied to the mixed powder layer II for a specific time to form a solid battery with a positive current collector I and a negative current collector I.

[0020] The technical solution of the present application can include the following beneficial effects:

[0021] The battery current collector of the present application is connected to the electrode active material layer by dry one-step forming of the mixed powder, avoiding complex processing of the interface surface roughness of the current collector, and forming a continuous metal particle layer bridged by metal particles in the mixed particle layer. The strength of the particle bridging position is lower than that of the metal particles. Once the battery is punctured, impacted or extruded, the metal particle bridging position with lower strength will break first, avoiding the formation of sharp structures that can pierce the electrolyte layer, and preventing interlayer short circuit or thermal runaway. Therefore, the technical solution solves the technical problems of complex interface processing of the solid battery and easy short circuit between the current collector layers in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0023] Figure 1 is a structural schematic diagram of a solid battery current collector according to an embodiment of the present application;

[0024] Figure 2 is a structural schematic diagram of a solid battery current collector during manufacturing according to an embodiment of the present application;

[0025] Figure 3 is a structural schematic diagram of a solid battery according to an embodiment of the present application.

[0026] In the figure: 1, negative current collector I; 11, mixed powder layer I; 111, metal particles; 112, binder particles; 12, negative active material layer I; 2, solid electrolyte layer I; 3, positive current collector I; 31, positive active material layer I; 32, mixed powder layer II; 4, positive active material layer II; 5, solid electrolyte layer II; 6, negative current collector II; 61, negative active material layer II; 62, mixed powder layer III; 7, negative active material layer III; 8, solid electrolyte layer III; 9, positive current collector II; 91, positive active material layer III; 92, mixed powder layer IV. DETAILED DESCRIPTION

[0027] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions of the present application will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0028] Figure 1 is a structural schematic diagram of a solid battery current collector according to an embodiment of the present application, as shown in Figure 1

[0029] The present application provides a solid battery current collector, comprising a mixed powder layer 11 and an electrode active material layer 12, the mixed powder layer 11 comprises metal particles 111 and binder particles 112, the metal particles 111 are bridged to each other in the mixed powder layer 11 to form a continuous metal particle layer, the mixed powder layer 11 is connected to the electrode active material layer 12 by dry one-time forming, and the electrode active material layer 12 is a positive active material layer or a negative active material layer.

[0030] Specifically, the battery current collector is connected to the electrode active material layer by dry one-time forming of the mixed powder, avoiding complex processing of the interface surface roughness of the current collector, and the metal particles in the mixed particle layer form a continuous metal particle layer bridged between the metal particles, the strength of the bridged position of the metal particles is lower than the strength of the metal particles, and once the battery is punctured, impacted, or extruded, the bridged position of the metal particles with lower strength will break first, avoiding the formation of a sharp structure that can puncture the electrolyte layer, and further preventing interlayer short circuit or thermal runaway.

[0031] As an optional embodiment, the metal particles 111 are one kind of particles or a mixture of multiple kinds of particles selected from copper, aluminum, nickel, and stainless steel particles.

[0032] ​Specifically, all metal materials known in the art that can be used for the current collector, metal particles that are electrically conductive and do not chemically react with battery materials, such as copper particles, aluminum particles, nickel particles, or stainless steel particles, or mixed particles of two or more of them, can be used as the metal particles of the current collector in the present technical solution.

[0033] As an optional embodiment, the binder particles 112 are hydrophobic adhesive particles and / or hydrophilic adhesive particles.

[0034] Specifically, the binder particles 112 can be particles of all adhesives known in the art that can be used for solid-state batteries, such as hydrophobic adhesive particles, including polyvinylidene fluoride, polytetrafluoroethylene, butadiene styrene rubber, or mixtures thereof; hydrophilic adhesive particles, including, for example, hydroxypropyl methylcellulose, sodium carboxymethylcellulose, hydroxyethyl cellulose, vinyl alcohol, or mixtures thereof; and mixtures of two or three of hydrophobic and hydrophilic adhesives.

[0035] As an optional embodiment, the mass ratio of the metal particles 111 to the binder particles 112 is 15 wt.% to 90 wt.%.

[0036] In another aspect, the present application provides a method for manufacturing a solid-state battery current collector, for manufacturing the solid-state battery current collector as described above, comprising the following steps:

[0037] Mixing the metal particles and the binder particles in a dry powder state to form a mixed powder;

[0038] Forming a mixed powder layer 11 on the electrode active material layer by applying, spraying, or doctor-blading the mixed powder;

[0039] Applying a specific pressure and a specific current between the mixed powder layer 11 and the electrode active material layer 12, and processing for a specific duration to obtain the solid-state battery current collector.

[0040] As an optional embodiment, the specific pressure is 0.1 MPa to 50 MPa, the specific current is 0.5 A to 150 A, and the specific duration is 0.1 s to 30 s.

[0041] Specifically, by the method of the present solution, as shown in Figure 2 the mixed powder is formed into a mixed powder layer 11 on the electrode active material layer by applying, spraying, or doctor-blading, and then the mixed powder layer is dry-formed once on the surface of the electrode active material layer, so that a continuous metal particle layer that functions as a current collector is achieved by bridging between the metal particles in the solid-state battery current collector.

[0042] In another aspect, the present application provides a solid-state battery including the solid-state battery current collector as described above, the solid-state battery current collector including a positive electrode current collector I3 and a negative electrode current collector I1, and further including a solid electrolyte layer I2, the positive electrode current collector I3, the solid electrolyte layer I2 and the negative electrode current collector I1 being sequentially arranged.

[0043] As an optional embodiment, a positive electrode active material layer I4, a solid electrolyte layer I5, a negative electrode current collector I6, a negative electrode active material layer I7, a solid electrolyte layer I8 and a positive electrode current collector I9 are sequentially arranged on the positive electrode current collector I3 side in a set number of repetitions.

[0044] Specifically, the solid-state battery includes a positive electrode current collector layer, a solid electrolyte layer and a negative electrode current collector layer; the solid electrolyte layer can be inorganic electrolyte powder, polymer electrolyte powder or composite inorganic-polymer electrolyte powder; Figure 3 is a diagram showing the general structure of the solid-state battery using the current collector according to the present embodiment, and specifically, the solid-state battery has 1 to n+1 solid-state battery units according to the number of repetitions 0 to n. The first solid-state battery unit includes a positive electrode layer, a negative electrode layer and a solid electrolyte layer between the positive electrode and the negative electrode, all in powder form. Except for the positive electrode layer and the negative electrode layer on the outermost layer, the positive electrode includes a positive electrode current collector layer and a positive electrode active material powder layer; the negative electrode includes a negative electrode current collector layer and a negative electrode active material powder layer. The solid electrolyte layer in each unit of the solid-state battery can completely separate the positive electrode layer and the negative electrode layer.

[0045] The solid-state battery of the present embodiment as a whole can have a customized shape, which can be a combination of shapes formed by different numbers of solid-state battery units.

[0046] The solid-state battery can be pressurized or heated or pressurized and heated as needed to promote more intimate bonding between the layers, and even thermoplastic deformation of the polymer layer in the solid-state battery.

[0047] In another aspect, the present application provides a manufacturing method of a solid-state battery for manufacturing the solid-state battery as described above, including the following steps:

[0048] Mixing the metal particles and the binder particles in a dry powder state to form a mixed powder;

[0049] Forming a mixed powder layer I11 on the negative electrode active material layer I12 by coating, spraying or doctor-blading the mixed powder;

[0050] Applying a specific pressure and a specific current for a specific time between the mixed powder layer I11 and the negative electrode active material layer I12 to form a negative electrode current collector I1;

[0051] A solid electrolyte layer 12 is stacked on the negative active material layer 11, and a positive active material layer 31 is stacked on the solid electrolyte layer 12, and then a mixed powder layer 32 is formed on the positive active material layer 31 by coating, spraying or doctor blading;

[0052] A specific pressure and a specific current are applied to the mixed powder layer 32 for a specific time to form a solid battery with a positive current collector 13 and a negative current collector 11.

[0053] As an optional embodiment, the following steps are further included:

[0054] A positive active material layer 14 is stacked on the mixed powder layer 32, a solid electrolyte layer 15 is stacked on the positive active material layer 14, and a negative active material layer 161 is stacked on the solid electrolyte layer 15, and then a mixed powder layer 162 is formed on the negative active material layer 161 by coating, spraying or doctor blading;

[0055] A specific pressure and a specific current are applied to the mixed powder layer 162 for a specific time to form a negative current collector 16.

[0056] A negative active material layer 17 is stacked on the mixed powder layer 162, a solid electrolyte layer 18 is stacked on the negative active material layer 17, and a positive active material layer 191 is stacked on the solid electrolyte layer 18, and then a mixed powder layer 192 is formed on the positive active material layer 191 by coating, spraying or doctor blading;

[0057] A specific pressure and a specific current are applied to the mixed powder layer 192 for a specific time to form a positive current collector 19.

[0058] The above steps are repeated according to the set number of times.

[0059] Specifically, the current collector layer is directly formed on the surface of the positive and negative active material layers by dry one-time molding, and the positive and negative active material layers are tightly combined with the current collector layer.

[0060] By applying a pressure of 0.1MPa-50MPa and a current of 0.5A-150A for 0.1s-30s, the layers of the solid battery are more tightly combined, and even the polymer layer in the solid battery is thermoplastically deformed.

[0061] The application provides a solid battery current collector, which is formed by a continuous metal particle layer formed by bridging of metal particles, and provides a current collecting function of the current collector in the solid battery; the continuous metal particle layer is formed by mixing metal particles and polymer binder particles in a dry powder state, and then applying, spraying or doctor-blading the mixed powder layer to a certain thickness and required shape, and then treating the mixed powder layer under a pressure of 0.1 MPa-50 MPa and a current of 0.5 A-150 A for 0.1 s-30 s to obtain a dry one-step forming solid battery current collector, wherein the binder particles are filled between the continuous metal particle layer and the electrode active material to bond the two layers.

[0062] The continuous metal particle layer for the current collecting function of the solid battery current collector provided by the application is achieved by bridging of the metal particles. The bridging position of the particles has a lower strength than the metal particles, and once the battery is punctured, impacted or extruded, the bridging position of the metal particles with lower strength will first break, avoiding formation of a sharp structure that can puncture the electrolyte layer, and further preventing interlayer short circuit or thermal runaway.

[0063] In the description of the present application, it should be pointed out that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for description purposes and cannot be understood as indicating or implying relative importance.

[0064] In the description of the present application, it should be pointed out that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, and can be internal communication of two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0065] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A solid battery current collector, characterized in that: It includes a mixed powder layer and an electrode active material layer, the mixed powder layer includes metal particles and binder particles, the metal particles are bridged with each other in the mixed powder layer to form a continuous metal particle layer, the mixed powder layer is connected to the electrode active material layer by dry one-time molding, the dry one-time molding is performed by applying a specific pressure and a specific current between the mixed powder layer and the electrode active material layer, and molding after a specific length of time, the electrode active material layer is a positive electrode active material layer or a negative electrode active material layer; the specific pressure is 0.1 MPa~50 Mpa, the specific current is 0.5 A~150 A, and the specific time is 0.1 s~30 s.

2. The solid battery current collector according to claim 1, wherein: The metal particles are one kind of particles or a mixture of multiple kinds of particles selected from the group consisting of copper, aluminum, nickel and stainless steel particles.

3. The solid battery current collector according to claim 2, wherein: The binder particles are hydrophobic binder particles and / or hydrophilic binder particles.

4. The solid battery current collector according to claim 3, wherein The mass ratio of the metal particles to the binder particles is 15 wt.% to 90 wt.%.

5. A method for manufacturing a solid battery current collector, characterized in that: The method for manufacturing the solid battery current collector according to any one of claims 1 to 4 comprises the following steps: mixing metal particles and binder particles in a dry powder state to form a mixed powder; forming a mixed powder layer on the electrode active material layer by coating, spraying or doctor blade coating the mixed powder; A specific pressure and a specific current are applied between the mixed powder layer and the electrode active material layer, and the solid battery current collector is obtained after treatment for a specific time.

6. A solid battery, characterized in that: It comprises a solid battery current collector as described in any one of claims 1 to 4, wherein the solid battery current collector comprises a positive electrode current collector I and a negative electrode current collector I, and the solid battery further comprises a solid electrolyte layer I, wherein the positive electrode current collector I, the solid electrolyte layer and the negative electrode current collector I are arranged in sequence.

7. The solid state battery according to claim 6, wherein On one side of the positive electrode current collector I, a positive electrode active material layer II, a solid electrolyte layer II, a negative electrode current collector II, a negative electrode active material layer II, a solid electrolyte layer III and a positive electrode current collector II are repeatedly arranged in sequence according to a set number of repetitions.

8. A method for manufacturing a solid battery, characterized in that: The method for manufacturing the solid state battery according to claim 6 or 7 comprises the following steps: mixing metal particles and binder particles in a dry powder state to form a mixed powder; forming a mixed powder layer I on the negative electrode active material layer I by coating, spraying or doctor blade coating the mixed powder; Applying a specific pressure and a specific current for a specific time between the mixed powder layer I and the negative electrode active material layer I to form a negative electrode current collector I; On one side of the negative electrode active material layer I, a solid electrolyte layer I and a positive electrode active material layer I are sequentially stacked, and then a mixed powder layer II is formed on the positive electrode active material layer I by coating, spraying or doctoring; A specific pressure and a specific current are applied to the mixed powder layer II for a specific period of time to form a solid battery with a positive electrode current collector I and a negative electrode current collector I.

9. The method for manufacturing a solid battery according to claim 8, wherein: The following steps are also included: On one side of the mixed powder layer II, a positive electrode active material layer II, a solid electrolyte layer II and a negative electrode active material layer II are sequentially stacked, and then a mixed powder layer III is formed on the negative electrode active material layer II by coating, spraying or doctoring; Applying a specific pressure and a specific current for a specific time on the mixed powder layer III to form a negative electrode current collector II; On one side of the mixed powder layer III, a negative electrode active material layer III, a solid electrolyte layer III and a positive electrode active material layer III are sequentially stacked, and then a mixed powder layer IV is formed on the positive electrode active material layer III by coating, spraying or doctoring; Applying a specific pressure and a specific current for a specific time to the mixed powder layer IV to form a positive electrode current collector II; The above steps are repeated cyclically according to the set number of repetitions.

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