Solid-state battery rubber frame and preparation method and application thereof

Abstract

The invention provides a solid-state battery rubber frame and a preparation method and application thereof, and relates to the technical field of solid-state batteries. Specifically, the solid-state battery rubber frame is arranged in an overhang area of a positive electrode or a negative electrode of a solid-state battery; the solid-state battery rubber frame comprises a polymer colloid and a surface functionalization modified sheet-shaped insulating filler. The invention provides the all-solid-state battery insulation rubber frame for introducing the flaky filler under the control of the magnetic field, and the all-solid-state battery insulation rubber frame can have a relatively high elastic modulus in the direction parallel to the pole piece and a relatively low elastic modulus in the direction perpendicular to the pole piece, so that deformation in the length and width directions of a battery cell in a densification process is inhibited, and the compactness of the battery cell is improved. And the thickness change of the pole pieces in the densification process is adapted to enable the pole pieces to be in close contact, and a continuous and stable supporting effect is provided for the battery cell structure in the circulation process.

Description

Technical Field

[0001] This invention relates to the field of solid-state battery technology, and more specifically, to a solid-state battery frame, its preparation method, and its application. Background Technology

[0002] Solid-state batteries have become a key research focus and a future development trend due to their high safety and high energy density. In the manufacturing of solid-state batteries, the positive electrode, solid electrolyte, and negative electrode are stacked using a lamination process, and interface contact is ensured through isostatic pressing. However, high voltage can easily cause the electrode edges to collapse or misalign, leading to a short circuit risk between the positive and negative electrodes. Therefore, it is necessary to insulate and encapsulate the electrodes, adding a protective frame for isolation.

[0003] Furthermore, due to the extremely high density of solid-state batteries and the presence of overhang regions between the positive and negative electrodes, the industry generally requires the addition of insulating frames in these regions to prevent the electrodes from cracking under high pressure. Based on the characteristics of solid-state batteries, the insulating frames must meet the following requirements: (1) have a high elastic modulus in the direction parallel to the electrode to suppress deformation in this direction during cell densification; (2) have a low elastic modulus in the direction perpendicular to the electrode to accommodate the volume changes of the silicon / silicon-carbon negative electrode during cell cycling. However, existing frames are generally made of uniform material with the same elastic modulus in the x, y, and z axes, which can only satisfy the requirement of a higher elastic modulus in the x and y directions (i.e., the direction parallel to the electrode) or a lower elastic modulus in the z direction (i.e., the direction perpendicular to the electrode), and cannot take into account the different requirements of different elastic moduli in each direction.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The primary objective of this invention is to provide a solid-state battery insulating frame. This invention improves the composition of the insulating frame of an all-solid-state battery by introducing sheet-like fillers under magnetic field control. The frame of this invention has a high elastic modulus in the direction parallel to the electrode and a low elastic modulus in the direction perpendicular to the electrode, thereby suppressing the deformation of the cell in the length and width directions during densification and adapting to the thickness changes of the positive electrode during densification, so that they are in close contact and provide continuous and stable support for the cell structure during cycling.

[0006] A second objective of this invention is to provide a method for preparing the solid-state battery frame described above.

[0007] A third objective of this invention is to provide an all-solid-state battery.

[0008] The fourth objective of this invention is to provide an electrical device.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: A solid-state battery adhesive frame is disposed on the overhang region of the positive or negative electrode of a solid-state battery. The solid-state battery frame comprises a polymer colloid and a surface-functionalized sheet-like insulating filler.

[0010] Preferably, the polymer colloid comprises at least one of organosilicon, acrylic acid, or epoxy resin; the sheet-like insulating filler comprises at least one of hexagonal boron nitride nanosheets, aluminum nitride nanosheets, and silicon carbide nanosheets.

[0011] Preferably, the mass ratio of the polymer colloid to the surface-functionalized sheet insulating filler is 60%~90%:10%~40%.

[0012] Preferably, the particle size of the sheet-like insulating filler is 1μm~10μm and the thickness is 50nm~200nm.

[0013] Preferably, the surface functionalization modification includes: A reaction solution containing the sheet-like insulating filler and silane coupling agent was prepared and refluxed at 60℃~80℃ for 4h~6h. After centrifugation, washing and drying, the surface-functionalized sheet-like insulating filler was obtained.

[0014] Preferably, the solid-state battery frame corresponds exactly to the overhang region; the thickness of the solid-state battery frame is the same as the thickness of the positive or negative electrode sheet.

[0015] A method for preparing the solid-state battery adhesive frame includes the following steps: A composite adhesive is obtained by dispersing surface-functionalized sheet-like insulating fillers in an uncured polymer colloid. The composite adhesive is applied to the overhang area of ​​the positive or negative electrode to obtain the adhesive frame precursor; The solid battery frame is obtained by simultaneously applying curing and magnetic field treatment to the frame precursor.

[0016] Preferably, the intensity of the magnetic field treatment is 1.0T~2.0T, and the direction of the magnetic field treatment is perpendicular to the plane of the electrode.

[0017] An all-solid-state battery, including the solid-state battery housing.

[0018] An electrical device includes the aforementioned solid-state battery housing.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The all-solid battery insulating frame of the present invention has a low elastic modulus in the direction perpendicular to the electrode sheet, and the support structure is stable in the vertical direction. The low elastic modulus in the vertical direction enables it to maintain the same thickness as the densified positive electrode and keep its interior in close contact.

[0020] (2) The all-solid battery insulating frame of the present invention has a high elastic modulus in the direction parallel to the electrode sheet, and is not prone to deformation in the direction parallel to the electrode sheet during the densification process of the cell, thereby effectively suppressing the changes in the length and width of the cell during the densification process. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 A side view of the solid-state battery adhesive frame of the present invention is provided; Figure 2 A top view of the solid-state battery frame of the present invention is provided. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0024] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] The first aspect of the present invention is to provide a solid battery frame that can satisfy: firstly, provide structural stability in the vertical direction, and the low elastic modulus in the vertical direction allows it to maintain consistency with the thickness after densification of the positive electrode, thus always maintaining close contact within it; secondly, suppress dimensional changes of the battery cell after densification, and the high elastic modulus in the horizontal direction can stabilize the deformation of the electrode sheet, reducing or even avoiding the probability of breakage in the fragile overhang area of ​​the battery cell due to huge deformation (5%~10%).

[0026] The solid-state battery frame of the present invention comprises the following components: a polymer colloid and a surface-functionalized sheet-like insulating filler.

[0027] In a preferred embodiment, the polymer colloid comprises at least one of silicone, acrylic acid, or epoxy resin. It is noteworthy that those skilled in the art can select the polymer colloid to match solid electrolytes of different compositions (such as oxide solid electrolytes or sulfide solid electrolytes) to achieve good chemical compatibility, curability, and high elasticity.

[0028] In a preferred embodiment, the sheet-like insulating filler includes at least one of hexagonal boron nitride (h-BN) nanosheets, aluminum nitride (AlN) nanosheets, and silicon carbide (SiC) nanosheets, which have good thermal conductivity and electrical insulation properties, and more preferably boron nitride nanosheets.

[0029] In a preferred embodiment, the particle size of the sheet-like insulating filler is 1μm to 10μm, including but not limited to any one or any two of the values ​​1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 (μm), and the thickness of the sheet-like insulating filler is 50nm to 200nm, including but not limited to any one or any two of the values ​​50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, and 200 (nm).

[0030] As a preferred embodiment, the surface functionalization modification includes the following steps: preparing a reaction solution containing the sheet-like insulating filler and the silane coupling agent, refluxing the reaction at 60℃~80℃ for 4h~6h, and then centrifuging, washing, and drying to obtain the surface-modified insulating filler.

[0031] In a more preferred embodiment, the solvent of the reaction solution includes anhydrous ethanol and deionized water, with a volume ratio of (90~98):(2~10), and the mass percentage of the solvent in the reaction solution is 92%~99%.

[0032] In a more preferred embodiment, the silane coupling agent includes, but is not limited to, KH-550, KH-560, etc., and the mass ratio of the silane coupling agent to the sheet-like insulating filler raw material is 1% to 5%.

[0033] It is understood that this invention achieves surface functionalization modification of sheet-like insulating fillers. Specifically, after hydrolysis, the silane coupling agent generates silanol groups, which undergo dehydration condensation with hydroxyl groups at defects on the filler surface to form stable Si-OB covalent bonds. This solves the interfacial compatibility problem between nanosheets and colloids, achieving uniform dispersion. At the same time, the silane coupling agent significantly improves the macroscopic mechanical strength, modulus, and toughness of the composite frame by connecting the two phases through strong covalent bonds.

[0034] In a preferred embodiment, the mass ratio of the polymer colloid to the surface-functionalized sheet insulating filler is 60%~90%:10%~40%.

[0035] In this invention, the solid-state battery frame is disposed in the overhang region of the positive or negative electrode of the solid-state battery. It is understood that the overhang region conforms to the conventional definition in the art. Overhang refers to the portion in which the length and width of one electrode (such as the negative electrode) exceeds the design of the other electrode (such as the positive electrode) when the positive and negative electrode sheets are stacked or wound. Intuitively, the active material of one electrode completely covers the active material of the other electrode in the planar projection, and the extra part is the overhang region.

[0036] Furthermore, in this invention, the area of ​​the solid-state battery adhesive frame completely coincides with the overhang area, and the thickness of the solid-state battery adhesive frame is the same as the thickness of the positive or negative electrode sheet. For example... Figure 1 The diagram shows a side view of the positive and negative electrode plates and the adhesive frame. It can be clearly seen that the thickness of the adhesive frame and the positive electrode are the same. Figure 1 (This will be illustrated using the example of an overhang region at the negative electrode). Figure 2 The diagram provided is a top-down view, with the black area representing the overhang.

[0037] In a preferred embodiment, the thickness of the solid-state battery adhesive frame is the same as the thickness of the positive or negative electrode sheet; when the negative electrode has an overhang region, the thickness of the solid-state battery adhesive frame is the same as the thickness of the positive electrode sheet, and when the positive electrode has an overhang region, the thickness of the solid-state battery adhesive frame is the same as the thickness of the negative electrode sheet.

[0038] A second aspect of the present invention is to provide a method for preparing a solid-state battery frame as described in the first aspect, which mainly includes the following steps: A surface-functionalized sheet-like insulating filler is dispersed in an uncured polymer colloid to obtain a composite adhesive; the composite adhesive is coated onto the overhang region of the positive or negative electrode to obtain a frame precursor; the frame precursor is simultaneously subjected to curing and magnetic field treatment to obtain a solid-state battery frame.

[0039] In a preferred embodiment, the dispersion can be achieved by one or more of the following methods: high-speed shearing, ball milling, or ultrasonic treatment, to ensure that the filler is uniformly dispersed without significant agglomeration.

[0040] In a preferred embodiment, the coating is performed by dispensing or 3D printing.

[0041] In a preferred embodiment, the curing process includes at least one of heat treatment or ultraviolet treatment, depending on the type of polymer colloid used. Different polymer colloids have different curing methods, and those skilled in the art can adaptably select the heating curing temperature or the UV light source wavelength.

[0042] In a preferred embodiment, the intensity of the magnetic field treatment is 1.0T to 2.0T, and the direction of the magnetic field is perpendicular to the plane of the pole pieces. In some embodiments, the strong static magnetic field of the magnetic field treatment of the present invention is generated by an electromagnet or permanent magnet device, and under the action of the magnetic field, all sheet-like insulating fillers will be uniformly arranged horizontally.

[0043] In a preferred embodiment, the duration of the magnetic field treatment is 2 min to 30 min.

[0044] A third aspect of the present invention is to provide an all-solid-state battery, comprising the solid-state battery housing as described in the first aspect. It is understood that, excluding the solid-state battery housing, the all-solid-state battery should include positive and negative electrodes, an electrolyte, and other necessary or non-essential functional components or packaging assemblies, which can be arbitrarily selected and combined by those skilled in the art; the inclusion of the solid-state battery housing as described in the present invention in the all-solid-state battery constitutes an embodiment of the present invention.

[0045] A fourth objective of this invention is to provide an electrical device comprising a solid-state battery housing as described in the first aspect. It is understood that the electrical device can be any device or apparatus that relies on electrical energy for operation, including but not limited to new energy vehicles, building electrical equipment, industrial electrical appliances, household and agricultural electrical appliances, etc.; when the solid-state battery housing is included, any electrical device equipped with the solid-state battery housing can be considered an embodiment of this invention.

[0046] The following are embodiments and comparative examples of the present invention; all embodiments and comparative examples are assembled into pouch cells using the following baseline process: using a silicon-carbon negative electrode sheet with an overhang of 2 mm and a negative electrode size of 10 cm × 15 cm, a 2 mm wide and 10 μm thick adhesive frame with the same thickness as the high-nickel ternary positive electrode sheet (100 μm) is constructed in the edge region of the negative electrode sheet; 10 cells are prepared for each embodiment or comparative example, and each cell is assembled with 20 positive electrodes and 20 negative electrodes to obtain a bare cell, and the assembly process is as follows: S1. Surface functionalized filler: h-BN nanosheets were dispersed in a composite solvent of anhydrous ethanol and deionized water in a ratio of 95:5. Silane coupling agent KH-550, accounting for 3% of the mass of the nanosheets, was added. The mixture was refluxed at 70°C for 5 hours. After centrifugation, washing, and drying, the surface-modified h-BN filler was obtained.

[0047] S2. Preparation of composite adhesive: The surface-modified h-BN filler is mixed and dispersed in the uncured polymer colloid, and a uniform and stable composite adhesive is obtained by high-speed shearing.

[0048] S3. Frame Forming: The composite adhesive is applied to the negative electrode overhang area using dispensing or 3D printing to form an uncured frame.

[0049] S4. Magnetic field orientation controlled curing: A magnetic field perpendicular to the plane of the electrode is applied to the uncured frame, and the frame is cured by heating or ultraviolet light irradiation to obtain an insulating frame integrally formed with the electrode that has efficient buffering of cyclic stress in the vertical direction of the electrode and constrains the deformation of the electrode in the in-plane direction.

[0050] Furthermore, the specific implementation details of the embodiments and comparative examples of the present invention are as follows: Example 1 In this embodiment, epoxy resin is used as the polymer colloidal matrix in S2, and the mass ratio of the colloidal resin to the h-BN filler is 90%:10%; dispensing is used in S3; and curing is carried out in S4 by heating at 80°C with a magnetic field strength of 1.0T.

[0051] Example 2 It is basically the same as Example 1, except that: in S2, the epoxy resin is replaced with acrylic glue; and in S4, 360nm ultraviolet light is used for UV curing.

[0052] Example 3 It is basically the same as Example 1, except that: in S2, the epoxy resin is replaced with silicone water; and in S4, 360nm ultraviolet light is used for UV curing.

[0053] Example 4 It is basically the same as Example 3, except that the magnetic field strength in S4 is 2.0T.

[0054] Comparative Example 1 It is basically the same as Example 3, except that no surface-modified h-BN filler was added in S2.

[0055] Comparative Example 2 It is basically the same as Example 3, except that no magnetic field is applied in S4.

[0056] Test case Ten cells prepared for each embodiment or comparative example were densified and subjected to isostatic pressing at 500 MPa for 5 min. The deformation of the ten cells in the width and length directions was recorded, and the average value of the deformation in the two directions was calculated and recorded in Table 1.

[0057] The deformation is calculated as follows: the ratio of the difference in side length in the width / length direction before and after densification to the side length in the width / length direction before densification.

[0058] The densified cells in each example were subjected to 100 cycle tests at a 0.1C rate. The average value of the cycle capacity retention of the 10 cells was calculated and recorded in Table 1.

[0059] Table 1

[0060] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A solid-state battery grommet, characterized by, The solid-state battery glue frame is arranged in an overhang area of a positive electrode or a negative electrode of the solid-state battery. The solid-state battery glue frame comprises a polymer glue and a surface-functionalized modified sheet-shaped insulating filler.

2. The solid-state battery gasket of claim 1, wherein, The polymer glue comprises at least one of silicone, acrylic or epoxy resin. And / or, the sheet-shaped insulating filler comprises at least one of hexagonal boron nitride nanosheet, aluminum nitride nanosheet or silicon carbide nanosheet.

3. The solid-state battery gasket of claim 1, wherein, The mass ratio of the polymer glue to the surface-functionalized modified sheet-shaped insulating filler is 60%-90%:10%-40%.

4. The solid-state battery gasket of claim 1, wherein, The particle size of the sheet-shaped insulating filler is 1-10 microns, and the thickness is 50-200 nanometers.

5. The solid-state battery gasket of claim 1, wherein, The surface-functionalized modification comprises: A reaction solution comprising the sheet-shaped insulating filler and a silane coupling agent is prepared, and refluxed at 60-80°C for 4-6 hours, and then the surface-functionalized modified sheet-shaped insulating filler is obtained after centrifugation, washing and drying.

6. The solid-state battery gasket of claim 1, wherein, The solid-state battery glue frame completely corresponds to the overhang area, and the thickness of the solid-state battery glue frame is the same as the thickness of the electrode sheet of the positive electrode or the negative electrode.

7. The method of claim 1 to 6, wherein The method comprises the following steps: The surface-functionalized modified sheet-shaped insulating filler is dispersed in the uncured polymer glue to obtain a composite glue; The composite glue is coated on the overhang area of the positive electrode or the negative electrode to obtain a glue frame precursor; The glue frame precursor is subjected to simultaneous solidification treatment and magnetic field treatment to obtain the solid-state battery glue frame.

8. The preparation method according to claim 7, characterized in that, The strength of the magnetic field treatment is 1.0-2.0T, and the magnetic field direction of the magnetic field treatment is perpendicular to the direction of the electrode sheet plane. Preferably, the duration of the magnetic field treatment is 2-30 minutes.

9. An all-solid battery, characterized by, The method comprises the solid-state battery glue frame according to any one of claims 1-6.

10. An electric device, characterized by The method comprises the solid-state battery glue frame according to any one of claims 1-6.

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