CN115240982A

CN115240982A - High-temperature laminated film capacitor and preparation method thereof

Info

Publication number: CN115240982A
Application number: CN202210935717.XA
Authority: CN
Inventors: 沈洋; 任伟斌; 杨敏铮
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2022-08-04
Filing date: 2022-08-04
Publication date: 2022-10-25

Abstract

The invention discloses a high-temperature laminated film capacitor and a preparation method thereof, wherein the capacitor comprises: the packaging structure comprises a substrate, an inner core, a terminal electrode and a packaging layer; the inner core comprises at least three dielectric layers and at least two inner electrode layers, the dielectric layers and the inner electrode layers are alternately stacked, the dielectric layer positioned at the lowest end on the inner core is arranged on the substrate, the dielectric layer is arranged at the uppermost end of the inner core, and the dielectric layer comprises soluble high-temperature polymer; the terminal electrodes comprise a first terminal electrode and a second terminal electrode, the first terminal electrode is arranged on one side of the substrate and is connected with at least one inner electrode layer, and the second terminal electrode is arranged on the other side of the substrate and is connected with the rest inner electrode layers; the encapsulation layer encapsulates the substrate, the inner core, and the terminal electrodes, and ends of the first terminal electrode and the second terminal electrode are not encapsulated. The high-temperature laminated film capacitor has good reliability at a high temperature of not less than 150 ℃.

Description

High-temperature laminated film capacitor and preparation method thereof

Technical Field

The invention belongs to the technical field of capacitors, and particularly relates to a high-temperature laminated film capacitor and a preparation method thereof.

Background

The dielectric film capacitor has intrinsic extremely fast charge-discharge rate and ultrahigh power density, is an extremely important power type energy storage device, and plays a key role in power grid frequency modulation, new energy grid connection, high-power energy storage and pulse power systems of electric vehicles and the like. The organic film capacitor is widely applied to industries such as electric automobiles, wind power, photovoltaics, illumination, railway locomotives and the like by virtue of the advantages of light weight, low cost, easiness in large-area preparation, high dielectric strength, unique self-healing property, no liquid medium, easiness in integration and the like of a polymer dielectric medium. In recent years, the fields of oil gas exploration, electric automobiles and the like have great urgent requirements on high-energy storage density electrostatic capacitors for high temperature (more than or equal to 150 ℃). With the demands, the electrostatic capacitor has a development trend of high temperature, thin layer and high voltage resistance.

The film capacitor has two element structures of a winding type and a laminated type, compared with the traditional winding film capacitor, the laminated polymer film capacitor (MLPC) meets the development requirement of the information industry, and has the advantages of small volume, good size consistency, low inductance and equivalent series resistance, good interlayer consistency (no internal stress), excellent long-term usability, strong anti-interference capability and pulse current resistance capability, suitability for large-scale production and the like. The current lamination process mainly comprises the following steps: (1) Winding (winding the metallized film on a strip-shaped core strip); (2) spraying gold; (3) heat setting; (4) slicing (cutting the laminated element from the core strip); (5) welding a terminal electrode and a lead; (6) packaging; and (7) testing and checking. The preparation process is used for all the high-temperature (125 ℃) polyester laminated capacitors at present. Recently SABIC company reported that polyetherimide (ULTEM) is based ^TM PEI (UTF-120)), however, at present, MLPC (multi-layer printed circuit board) for high temperature (not less than 150 ℃) is rarely reported, and a novel preparation process needs to be developed.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. To this end, an object of the present invention is to provide a high-temperature stacked thin film capacitor and a method for manufacturing the same. The high-temperature laminated film capacitor has good reliability at a high temperature of not less than 150 ℃.

In one aspect of the invention, a high temperature laminated thin film capacitor is provided. According to an embodiment of the present invention, the high temperature laminated thin film capacitor includes:

a substrate;

an inner core, wherein the inner core comprises at least three dielectric layers and at least two inner electrode layers, the dielectric layers and the inner electrode layers are alternately stacked, the dielectric layers positioned at the lowermost end are arranged on the substrate, the uppermost end of the inner core is the dielectric layers, and the dielectric layers comprise soluble high-temperature polymers;

the terminal electrode comprises a first terminal electrode and a second terminal electrode, the first terminal electrode is arranged on one side of the substrate and is connected with the at least one inner electrode layer, and the second terminal electrode is arranged on the other side of the substrate and is connected with the rest of the inner electrode layers;

an encapsulation layer encapsulating the substrate, core, and terminal electrodes, and ends of the first and second terminal electrodes are not encapsulated.

According to the high-temperature laminated film capacitor of the embodiment of the invention, the inner core comprising at least three dielectric layers and at least two inner electrode layers is arranged on the substrate, the dielectric layers and the inner electrode layers are alternately stacked, the dielectric layer positioned at the lowest end on the inner core is arranged on the substrate, the uppermost end of the inner core is the dielectric layer, the first end electrode and the second end electrode are respectively arranged at two sides of the substrate, the first end electrode is connected with at least one inner electrode layer, the second end electrode is connected with the rest inner electrode layers, the packaging layer is finally formed on the substrate, the inner core and the end electrodes, and the end parts of the first end electrode and the second end electrode are not packaged, wherein the dielectric layer comprises a soluble high-temperature polymer which has high glass transition temperature and wide band gap, so that the capacitor has larger application potential in the field of high-temperature energy storage, and the breakdown field intensity of a dielectric system can be greatly improved. Thus, the capacitor of the present application has good reliability at a high temperature of not less than 150 ℃.

In addition, the high-temperature stacked film capacitor according to the above embodiment of the present invention may further have the following additional technical features:

in some embodiments of the invention, the substrate has a thickness of no less than 5 μm.

In some embodiments of the invention, the inner electrode layer is a metal foil layer or a metalized electrode.

In some embodiments of the present invention, a thickness of a single layer of the dielectric layer is 1 to 10 μm.

In some embodiments of the invention, the glass transition temperature of the soluble high temperature polymer is not less than 150 ℃.

In some embodiments of the present invention, the inner core comprises at least three inner electrode layers, the first end electrode is connected to the spaced apart inner electrode layers with one of the inner electrode layers therebetween, and the second end electrode is connected to the remaining inner electrode layers. This can increase the capacitance of the capacitor.

In some embodiments of the present invention, one of the two adjacent internal electrode layers extends beyond the edge of the dielectric layer in a first direction, and the other extends beyond the edge of the dielectric layer in an opposite direction. Therefore, the connection of the internal electrode layer and the terminal electrode is facilitated.

In still another aspect of the present invention, the present invention provides a method of manufacturing the above-described high-temperature stacked thin film capacitor. According to an embodiment of the invention, the method comprises:

(1) Mixing a soluble high-temperature polymer with a solvent to obtain a spraying liquid, spraying the spraying liquid on a substrate after ultrasonic atomization, and then carrying out heat treatment to form a dielectric layer on the substrate;

(2) Forming an internal electrode layer on the dielectric layer;

(3) After the ultrasonic atomization of the spraying liquid, spraying the spraying liquid on the inner electrode layer, and then carrying out heat treatment;

(4) Repeating the steps (2) and (3) so as to alternately form at least three dielectric layers and at least two inner electrode layers on the substrate, wherein the dielectric layers are arranged at the uppermost end of the inner core, and then performing hot-press forming;

(5) Arranging a first terminal electrode at one side of the substrate and connecting the first terminal electrode with the at least one inner electrode layer, and arranging a second terminal electrode at the other side of the substrate and connecting the second terminal electrode with the rest of the inner electrode layers;

(6) And (5) packaging the device obtained in the step (5) so as to obtain the high-temperature laminated film capacitor.

According to the method of the embodiment of the invention, the ultrasonic spraying process is adopted to spray the spraying liquid obtained by mixing the soluble high-temperature polymer and the solvent on the substrate, and then the heat treatment is carried out to form the dielectric layer, so that the ultrasonic spraying process not only ensures that the spraying liquid has good spreadability on the substrate and the obtained dielectric layer has uniform thickness distribution, but also can prepare the ultrathin dielectric layer. Meanwhile, the dielectric layer with the corresponding size can be obtained by simply adjusting the template according to the corresponding size by adopting an ultrasonic spraying process, and compared with the method that the post-treatment is carried out on the obtained film layer after the film is formed by the processes of casting, melt extrusion and the like, the post-treatment operation is not needed. Then, an inner electrode layer is formed on the dielectric layer, and the ultrasonic atomization spraying liquid is continuously sprayed on the inner electrode layer, and then the dielectric layer is formed through heat treatment. Repeating the steps, preparing an inner core comprising at least three dielectric layers and at least two inner electrode layers on the substrate, alternately stacking the dielectric layers and the inner electrode layers in the inner core, performing hot-press molding, arranging the first end electrode on one side of the substrate and connecting the first end electrode with at least one inner electrode layer, arranging the second end electrode on the other side of the substrate and connecting the second end electrode with the rest of the inner electrode layers, and finally packaging the device to obtain the capacitor with good reliability at the high temperature of not less than 150 ℃.

In addition, the method of manufacturing a high-temperature stacked thin film capacitor according to the above embodiment of the present invention may further have the following additional technical features:

in some embodiments of the invention, the soluble high temperature polymer has a band gap energy of not less than 3eV. This can improve the reliability of the capacitor.

In some embodiments of the present invention, the spray coating fluid is prepared by mixing a soluble high temperature polymer, an organic semiconductor, and a solvent.

In some embodiments of the present invention, the trap energy of the soluble high temperature polymer and the charge trap constructed by the organic semiconductor is not less than 1.5eV.

In some embodiments of the invention, the organic semiconductor comprises

At least one of (a).

In some embodiments of the invention, in the step (2), the inner electrode layer is a metal foil layer, and the metal foil layer is placed on the dielectric layer for cold pressing, wherein the cold pressing is performed at 30-60 ℃ and at 10-20t in a vacuum air compressor, and the vacuum negative pressure is not higher than 80Pa; or the inner electrode layer is a metallized electrode which is obtained by high vacuum thermal resistance evaporation.

In some embodiments of the invention, in the step (4), the temperature of the hot press forming is not lower than 150 ℃, the time is not lower than 1h, the pressure is 1-15 t, and the hot press forming is performed in a vacuum press, and the vacuum negative pressure is not higher than 80Pa. Therefore, the structure of the capacitor inner core can be more stable and compact.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a structural diagram of a high-temperature laminated thin film capacitor according to an embodiment of the present invention;

FIG. 2 is a schematic flow chart of a method for fabricating a high temperature stacked film capacitor according to an embodiment of the present invention;

FIG. 3 is a schematic flow chart of a process for fabricating a high temperature stacked thin film capacitor according to an embodiment of the present invention;

FIG. 4 a shows a fluorine-containing polyimide in example 1

A physical diagram of a foil-type laminated film capacitor (f-MLPC) with an active layer surface constructed by using a film as a dielectric layer and an aluminum foil as an internal electrode layer being about 5cm multiplied by 5 cm; FIG. 4, panel b and FIG. 4, panel c are f-MLPC soft-encapsulated with cross-linked polydimethylsiloxane and f-MLPC hard-encapsulated with cross-linked epoxy resin, respectively; FIG. 4 d is an SEM photograph showing the internal cross-sectional structure of f-MLPC obtained in example 1; FIG. 4, panel e, is an EDS plot of F used in the F-MLPC obtained from example 1 to represent the distribution of dielectric layers; FIG. 4 is a graph of f-MLPC obtained in example 1 showing the distribution of aluminum foil in the inner electrode layer by EDS using Al;

FIG. 5 is a graph of capacitance and loss factor frequency changes at 25 deg.C, 50 deg.C, 100 deg.C and 150 deg.C for the capacitor of example 1;

FIG. 6 is a graph of capacitance and dissipation factor measurements for capacitors of example 1 at room temperature at various degrees of bending;

figure 7 a is a schematic diagram of a metallized laminated film capacitor with three dielectric active layers of example 2;

FIG. 7 b is a schematic sectional view of the capacitor obtained in example 2; FIG. 7 c is a fluorine-containing polyimide

A physical diagram of a metallized laminated film capacitor (m-MLPC) with an active layer plane constructed with a film as a dielectric layer and aluminum metallization as an internal electrode layer of about 2cm × 2 cm; FIG. 7d is a cross-sectional view of m-MLPC prepared in example 2;

FIG. 8 is a graph showing the measurement results of the capacitance and the dissipation factor at 150 ℃ of the capacitor of example 2.

Detailed Description

The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In one aspect of the invention, a high temperature laminated thin film capacitor is provided. According to an embodiment of the present invention, referring to fig. 1, the high temperature stacked thin film capacitor includes: substrate 100, core 200, terminal electrodes 300, and encapsulation layer 400.

It should be noted that the substrate 100 is a conventional material in the art, and the substrate 100 can be selected by those skilled in the art according to the actual application, such as but not limited to aluminum foil, copper foil, glass plate or polymer film with a glass transition temperature of not lower than 150 ℃. Further, the thickness of the substrate 100 is not less than 5 μm, for example, 10 to 20 μm.

According to the capacitor of the above embodiment of the present invention, the inner core 200 includes at least three dielectric layers 201 and at least two inner electrode layers 202, the dielectric layers 201 and the inner electrode layers 202 are alternately stacked, and the dielectric layer 201 at the lowermost end of the inner core 200 is disposed on the substrate 100, the dielectric layer 201 at the uppermost end of the inner core 200 is the dielectric layer 201, the dielectric layer 201 at the uppermost end of the inner core 200 can protect the inner electrode layer 202 adjacent thereto, and the dielectric layer 201 includes a soluble high temperature polymer. The soluble high-temperature polymer has high glass transition temperature and wide band gap, so that the capacitor has great application potential in the field of high-temperature energy storage, and the breakdown field intensity of a dielectric system can be greatly improved. Thus, the capacitor of the present application can maintain good reliability at high temperatures of not less than 150 ℃. It should be noted that the skilled person can select the specific type of the soluble high temperature polymer according to the actual needs, for example, the soluble polymer with a glass transition temperature of not less than 150 ℃ and a band gap of not less than 3eV is used.

According to an embodiment of the present invention, the single dielectric layer 201 has a thickness of 1 to 10 μm. It will be understood by those skilled in the art that the thickness of the dielectric layer 201 can be controllably adjusted according to the change of the spraying process and the spraying solution, and those skilled in the art can select the thickness of the dielectric layer 201 according to the actual application, such as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm. Further, the type of the inner electrode layer 202 can be determined according to the type of the capacitor, for example, for a foil type capacitor, the inner electrode layer 202 adopts a metal foil layer, and the metal foil is attached to the dielectric layer 201 through cold pressing, wherein the temperature of the cold pressing is 30-60 ℃, the pressure is 10-20t, the cold pressing is performed in a vacuum air compressor, and the vacuum negative pressure is not higher than 80Pa; for the metallized film capacitor, the internal electrode layer 202 employs a metallized electrode obtained by high vacuum thermal resistance evaporation.

According to an embodiment of the present invention, the terminal electrode 300 includes a first terminal electrode 301 and a second terminal electrode 302, the first terminal electrode 301 is disposed on one side of the substrate 100 and connected to at least one of the inner electrode layers 202, and the second terminal electrode 302 is disposed on the other side of the substrate 100 and connected to the remaining inner electrode layers 202.

According to some embodiments of the present invention, the inner core 200 includes at least three inner electrode layers 202, a first terminal electrode 301 connected to the spaced inner electrode layers 202, and one inner electrode layer 202 between the spaced inner electrode layers 202, and a second terminal electrode 302 connected to the remaining inner electrode layers 202. It should be noted that "the inner electrode layers 202 arranged at intervals" may be understood as an arrangement of intervals between the inner electrode layers 202, for example, including a first inner electrode layer, a second inner electrode layer, and a third inner electrode layer in this order, where the positional relationship between the first inner electrode layer and the third inner electrode layer is an arrangement of intervals. Therefore, the capacitors can be connected in parallel by forming the capacitors between the inner electrode layers, and the capacity of the capacitor is improved.

According to some embodiments of the present invention, one of the two adjacent inner electrode layers 202 extends out of the edge of the dielectric layer 201 along a first direction, and the other extends out of the edge of the dielectric layer 201 along the opposite direction, so that adhesion of the two adjacent inner electrode layers 202 can be avoided, and the two spaced inner electrode layers 202 both extend along the same side of the dielectric layer 201, thereby facilitating connection of the terminal electrode 300 and the spaced inner electrode layers 202. Specifically, if the substrate 100 is made of a conductive material such as aluminum foil or copper foil, when the inner electrode layers 202 extending along the same direction are connected by hot pressing during the hot press molding process, the inner electrode layers 202 extending along the same direction and the inner electrode layers 202 extending along the opposite direction should be prevented from contacting the substrate 100 at the same time, so that the internal conduction of the device can be avoided, which can be achieved by widening the size of the dielectric layer 201 located at the lowermost end of the inner core 200.

It should be noted that the terminal electrode 300 may be a metal thin wire, such as a copper wire, which is adhered to both ends of the inner core 200 by a high temperature resistant conductive adhesive, such as a conductive silver paste.

According to an embodiment of the present invention, the encapsulation layer 400 encapsulates the substrate 100, the core 200, and the terminal electrode 300, and the ends of the first terminal electrode 301 and the second terminal electrode 302 are not encapsulated. According to an embodiment of the present invention, the encapsulation layer 400 may include a flexible cross-linked material, such as a flexible cross-linked material that uses cross-linked polydimethylsiloxane to achieve soft encapsulation, or a thermosetting material that uses cross-linked epoxy to achieve hard encapsulation.

In still another aspect of the present invention, the present invention provides a method of manufacturing the above-described high-temperature stacked thin film capacitor. Referring to fig. 2 and 3, according to an embodiment of the present invention, the method includes:

s100: mixing soluble high-temperature polymer and solvent to obtain spray coating liquid, ultrasonic atomizing, spraying on substrate, and heat treating

Adding a soluble high-temperature polymer into a solvent, fully stirring to uniformly disperse the soluble high-temperature polymer in the solvent to obtain a spraying liquid, then spraying the spraying liquid on a substrate after ultrasonic atomization in a spraying device, and carrying out heat treatment to form a dielectric layer on the substrate. Meanwhile, the dielectric layer with the corresponding size can be obtained by simply adjusting the template according to the corresponding size by adopting an ultrasonic spraying process, and compared with the method that the post-treatment is carried out on the obtained film layer after the film is formed by the processes of casting, melt extrusion and the like, the post-treatment operation is not needed. The soluble high-temperature polymer has high glass transition temperature and wide band gap, the high glass transition temperature improves the application potential of the soluble high-temperature polymer in the field of high-temperature energy storage, and the wide band gap can greatly improve the breakdown field intensity of a dielectric system. For example, the band gap energy of the soluble high-temperature polymer adopted by the application is not less than 3eV, so that the breakdown field strength of a dielectric system can be greatly improved. The adopted ultrasonic spraying method has simple process and low equipment cost, can efficiently prepare the high-quality ultrathin polymer-based dielectric layer in a large area, and solves the problem of high cost of preparing the high-quality ultrathin polymer-based dielectric layer by adopting melt extrusion and biaxial stretching.

According to an embodiment of the present invention, the glass transition temperature of the above soluble high temperature polymer is not lower than 150 ℃, for example, the soluble high temperature polymer of the present application includes, but is not limited to, at least one of fluorine-containing polyimide, polyimide and polyetherimide, wherein the fluorine-containing polyimide has a structure of

I.e. R is one of the following structures:

namely, the introduction of-CF in the polyimide structure ₃ The group can increase the intermolecular chain spacing, thereby weakening conjugation, improving the intrinsic band gap width of polyimide and further improving the breakdown field strength of F-PI.

Preferably, the fluorine-containing polyimide (F-PI) has a structural formula

And has a glass transition temperature of 340 ℃ and a chain pitch

And the band gap energy thereof is 3.53eV.

According to the embodiment of the invention, in order to further improve the breakdown field strength of the dielectric system, an organic semiconductor can be added in the process of preparing the spray coating liquid, namely, the spray coating liquid is prepared by mixing the soluble high-temperature polymer, the organic semiconductor and the solvent and then performing ultrasonic dispersion. By adding the organic semiconductor into the spraying liquid, the soluble high-temperature polymer and the organic semiconductor are compounded in trace amount to construct a deep trap, so that the movement of a current carrier can be greatly inhibited, and the breakdown field intensity of a dielectric system is greatly improved.

According to the embodiment of the invention, the trap energy of the charge trap constructed by the soluble high-temperature polymer and the organic semiconductor is not lower than 1.5eV. In order to make the trap energy of the charge trap constructed by the soluble high temperature polymer and the organic semiconductor larger, the organic semiconductor is selected to have a melting point of not less than 150 ℃, for example, the organic semiconductor includes but is not limited to

(PC61BM)、

(PC71BM)、

(DPDI)、

(ITIC). Specifically, the structural formula is

The trap energy of the F-PI and the charge trap constructed by the organic semiconductor (PC 61 BM) of (1) is 2eV.

It should be noted that the above-mentioned solvents include a main solvent and an auxiliary solvent, the main solvent is a conventional agent in the art as long as the main solvent is volatile and does not react with the soluble high-temperature polymer and the organic semiconductor, and the auxiliary solvent is a solvent which is volatile and helps to reduce the surface tension of the main solvent, so as to improve the spreadability of the solution on the substrate, and the specific type of the solvent can be selected by those skilled in the art according to the actual circumstances, for example, the main solvent includes but is not limited to at least one of N, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone, m-cresol, and dimethylsulfoxide, and the auxiliary solvent includes but is not limited to at least one of acetone and ethanol. Preferably, the solvent comprises N, N-dimethylformamide and acetone, and the volume ratio of the N, N-dimethylformamide to the acetone is 6:1-8:1, the spray liquid can be substantially completely spread on the substrate. Specifically, when the solvent is a mixed solution of N, N-dimethylformamide and acetone, in the process of preparing the spraying liquid, the soluble high-temperature polymer powder is firstly added into DMF (dimethyl formamide) to be dissolved to obtain a transparent solution, then the organic semiconductor is added into the solution to be subjected to ultrasonic dispersion, then the acetone is added into the dispersion liquid to be fully stirred to obtain the spraying liquid, and the ultrasonic dispersion power is 160-320W, and the frequency is 20kHz.

According to the embodiment of the invention, in the spraying liquid, the concentration of the soluble high-temperature polymer is 0.01-0.05 g/mL, and the volume concentration of the organic semiconductor is 0.1-1%. The inventors found that if the concentration of the soluble high-temperature polymer is too low, the amount of the solvent consumed becomes large and the film quality becomes poor; if the concentration of the soluble high-temperature polymer is too high, the spray head can be blocked by the spraying liquid; if the volume concentration of the organic semiconductor is too large, the energy storage performance of the film is seriously deteriorated; if the volume concentration of the organic semiconductor is too small, the performance of the film is improved a little. Therefore, the reliability of the dielectric layer can be improved by adopting the spraying liquid which comprises the soluble high-temperature polymer with the concentration of 0.01-0.05 g/mL and the organic semiconductor with the volume concentration of 0.1% -1%.

According to the embodiment of the invention, the ultrasonic atomization and the spraying meet at least one of the following conditions: the ultrasonic atomization power is 0.8-1.2W; the spraying height is 30-70 mm; the spraying working speed is 10-50 mm/s; the flow rate of the spraying liquid is 0.5-2 ml/min; the air guide pressure is 0.003-0.01MPa. In order to further improve the uniformity of the atomized spray film on the substrate, it is preferable that the above conditions are all satisfied.

According to an embodiment of the present invention, the above heat treatment may be performed by the following steps: firstly, heating a substrate of a wet film to 40-90 ℃ for 30-60min to obtain a quasi-dry film; then the quasi-dry film is placed in a blast oven at 40-90 ℃, heated to 150-250 ℃ along with the blast oven and kept for 2-10 h, and then the film is placed in a vacuum oven at more than 150 ℃ for treatment for 5-12 h. Thus, the residual solvent in the film can be completely removed by the heat treatment process.

S200: forming an internal electrode layer on the dielectric layer

In this step, an inner electrode layer 202 is formed on the dielectric layer obtained in S100, the type of the inner electrode layer 202 may be determined according to the type of the capacitor, for example, for a foil-type capacitor, the inner electrode layer 202 is a metal foil layer, the metal foil is attached to the dielectric layer by cold pressing, the temperature of the cold pressing is 30-60 ℃, the pressure is 10-20 tons, and the cold pressing is performed in a vacuum air compressor, and the vacuum negative pressure is not higher than 80Pa; for the metallized film capacitor, the internal electrode layer 202 is a metallized electrode obtained by high vacuum thermal resistance evaporation, and the size of the metallized electrode can be adjusted by a specific template, so that the matching of the internal electrode layer 202 is improved.

S300: spraying the spray liquid on the inner electrode layer after ultrasonic atomization, and then carrying out heat treatment

In this step, the spraying liquid in S100 is ultrasonically atomized, sprayed on the inner electrode layer 202, and then heat-treated to form the dielectric layer 201 on the inner electrode layer, wherein the conditions of the spraying liquid composition, the ultrasonic atomization, the spraying and the heat treatment are the same as those in S100.

S400: repeating steps S200 and S300

In this step, steps S200 and S300 are repeated to alternately stack at least three dielectric layers 201 and at least two internal electrode layers 202 on the substrate 100 with the dielectric layers 201 being the uppermost ends of the internal cores 200, and then, hot press molding is performed. It will be understood by those skilled in the art that the number of the dielectric layers 201 and the inner electrode layers 202 may be selected by those skilled in the art according to the actual requirement, as long as the dielectric layers 201 and the inner electrode layers 202 are alternately stacked and the dielectric layers 201 are located at the lowermost end and the uppermost end of the inner core 200. Furthermore, the hot-press shaping temperature is not lower than 150 ℃, the time is not lower than 1h, the pressure is 1-15 t, the process is carried out in a vacuum machine, the vacuum negative pressure is not higher than 80Pa, and the structure of the capacitor inner core can be more stable and compact under the hot-press shaping condition.

S500: adding a terminal electrode

In this step, a first terminal electrode 301 is disposed on one side of the substrate 100 and connected to at least one of the inner electrode layers 202, and a second terminal electrode 302 is disposed on the other side of the substrate 100 and connected to the remaining inner electrode layers 202, for example, the inner core 200 includes at least three inner electrode layers 202, the first terminal electrode 301 is connected to the inner electrode layers 202 spaced apart from each other, one inner electrode layer 202 is disposed between the inner electrode layers 202 spaced apart from each other, and the second terminal electrode 302 is connected to the remaining inner electrode layers 202. Therefore, the parallel connection of the capacitors formed between the inner electrode layers can be realized, and the capacity of the capacitor can be improved.

S600: packaging a device

In this step, the device is encapsulated, for example, the substrate 100, the core 200, and the terminal electrode 300 are encapsulated, and the ends of the first terminal electrode 301 and the second terminal electrode 302 are not encapsulated, resulting in a high-temperature stacked thin film capacitor. The encapsulation method is conventional in the art, and can be selected by those skilled in the art according to the actual application, for example, the encapsulation material can include a flexible cross-linked material or a thermosetting material, for example, the flexible cross-linked material uses cross-linked polydimethylsiloxane to realize soft encapsulation, and the thermosetting material uses cross-linked epoxy resin to realize hard encapsulation.

Therefore, the method has simple equipment and low capacitor preparation cost, can prepare a large-area capacitor, and can prepare the capacitor with good reliability at high temperature. It should be noted that the features and advantages of the high-temperature stacked thin film capacitor described above are also applicable to this method, and will not be described herein.

The invention will now be described with reference to specific examples, which are intended to be illustrative only and not to be limiting in any way.

The preparation method of the capacitor obtained in the embodiment 1 and the embodiment 2 comprises the following steps:

(1) Firstly F-PI powder (structural formula is shown in the specification)

) Adding into DMF, dissolving to obtain transparent solution, and adding acetone into the transparent solutionObtaining a spraying liquid from the liquid, spraying the spraying liquid on a substrate (aluminum foil) after ultrasonic atomization, heating the substrate to 40-70 ℃ after the spraying is finished, keeping the temperature for 0.5-1h for drying, then moving the substrate to a blast oven at 40 ℃, heating to 250 ℃ and keeping the temperature for 2h, then placing the substrate in a vacuum oven at 200 ℃ for treatment for 10h, completely removing the solvent in the film, and finally forming a dielectric layer on the substrate. Wherein the concentration of F-PI in the spraying liquid is 0.0139g/ml, and the volume ratio of DMF to acetone is 8:1; the ultrasonic atomization spraying conditions are as follows: the ultrasonic atomization power is 1W, the flow rate of the spraying liquid is 0.5ml/min, the spraying width is 1.5mm, the spraying height is 60mm, the working speed of spraying is 20mm/s, and the air guide pressure is 0.005MPa.

(2) And (2) placing an aluminum foil on the dielectric layer obtained in the step (1) and performing cold pressing, wherein the temperature of the cold pressing is 50 ℃, and the pressure is 15 tons.

(3) And (3) spraying the spraying liquid obtained in the step (1) on the inner electrode layer obtained in the step (2) after ultrasonic atomization, and then removing the solvent through heat treatment in the same way as the step (1).

(4) And (3) repeating the steps (2) and (3), namely preparing inner cores of the dielectric layers and the inner electrode layers with required quantity according to actual preparation, wherein one of the two adjacent inner electrode layers extends out of the edge of the substrate along the first direction, and the other inner electrode layer extends out of the edge of the substrate along the opposite direction, and then carrying out hot-press shaping.

(5) At least one inner electrode layer on one side of the substrate is connected with a first end electrode, the other side of the substrate is connected with the residual inner electrode layer to form a second end electrode, the inner electrode layers connected with the first end electrode are mutually spaced, an inner electrode layer is arranged between the inner electrode layers arranged at intervals, the first end electrode and the second end electrode are all thin copper wires, and the first end electrode and the second end electrode are adhered to two ends of the device through high-temperature conductive silver paste.

(6) And (5) packaging the device obtained in the step (5), and performing soft packaging by using cross-linked polydimethylsiloxane or performing hard packaging by using cross-linked epoxy resin.

FIG. 4A is a view showing a fluorine-containing polyimide in example 1

A physical diagram of a foil-type laminated film capacitor (f-MLPC) with an active layer surface constructed by using a film as a dielectric layer and an aluminum foil as an internal electrode layer being about 5cm multiplied by 5 cm; the b diagram in FIG. 4 and the c diagram in FIG. 4 are f-MLPC soft-packaged by using cross-linked polydimethylsiloxane and f-MLPC hard-packaged by using cross-linked epoxy resin, respectively. The internal cross-sectional structure of f-MLPC was characterized by scanning electron microscopy (SEM, d in FIG. 4) and Energy Dispersive Spectroscopy (EDS). EDS diagram of F (e diagram in FIG. 4) is used to represent the distribution of the dielectric layer; EDS diagram (f diagram in FIG. 4) of Al is used to represent the distribution of aluminum foil in the inner electrode layer. It is clear from the EDS diagram that the F-PI dielectric layers and the Al foil electrode layers are alternately arranged, the number of active layers of the dielectric layers is 6, the thickness of the dielectric layers is 6 micrometers, and the thickness of the electrode layers is 6 micrometers.

The capacitance and dissipation factor of the capacitor of example 1 were measured at 25 ℃, 50 ℃, 100 ℃ and 150 ℃.

The capacitance and the loss factor frequency changes at 25 ℃, 50 ℃, 100 ℃ and 150 ℃ of the capacitor of example 1 are shown in fig. 5. As is clear from FIG. 5, in the frequency range of 1kHz-10kHz, the change of capacitance and loss tangent with temperature is not large, the capacitance at each temperature at 1kHz is 85nF, and the loss tangent is changed from 0.014 at 25 ℃ to 0.032 at 150 ℃.

The capacitance and dissipation factor at different degrees of bending of the capacitor of example 1 were measured at room temperature.

The capacitance and dissipation factor measurements at different degrees of bending for the capacitor of example 1 at room temperature are shown in fig. 6. As can be seen from fig. 6, the capacitance and the loss factor of the capacitor at different curvatures do not change greatly at room temperature, which indicates that the flexibly packaged capacitor exhibits excellent flexible dielectric property stability.

Fig. 7 a is a schematic diagram of a metallized stacked film capacitor with three dielectric active layers according to example 2, and a schematic diagram of an internal cross section thereof is shown in fig. 7 b. FIG. 7 c is a fluorine-containing polyimide

Physical representation of a metallized laminated film capacitor (m-MLPC) with a thin film as a dielectric layer and an active layer surface constructed with metallized aluminum as an inner electrode layer of about 2cm × 2 cm; the edge is kept at 2mm, the number of dielectric layers of the device is 3, the outer end electrode is a thin copper wire, and the thin copper wire is adhered to the two ends of the device through high-temperature conductive silver paste. FIG. 7d is a cross-sectional view of the m-MLPC prepared in example 2, from which it can be seen that the thickness of the single dielectric layer is 3.4 μm. The capacitance and dissipation factor at 150 ℃ of the capacitor of example 2 were measured and the results are shown in FIG. 8. As can be seen from FIG. 8, the capacitance at 1kHz at 150 ℃ is 1.87nF, and the loss factor is 0.023.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Moreover, various embodiments or examples and features of various embodiments or examples described in this specification can be combined and combined by one skilled in the art without being mutually inconsistent.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A high temperature laminated film capacitor, comprising:

a substrate;

an inner core, wherein the inner core comprises at least three dielectric layers and at least two inner electrode layers, the dielectric layers and the inner electrode layers are alternately stacked, the dielectric layer positioned at the lowest end on the inner core is arranged on the substrate, the dielectric layer is arranged at the uppermost end of the inner core, and the dielectric layer comprises a soluble high-temperature polymer;

2. A high temperature laminated film capacitor according to claim 1, wherein said substrate has a thickness of not less than 5 μm.

3. A high temperature laminated film capacitor as claimed in claim 1, wherein said inner electrode layer is a metal foil layer or a metallized electrode;

optionally, the thickness of a single dielectric layer is 1-10 μm;

optionally, the glass transition temperature of the soluble high temperature polymer is not less than 150 ℃.

4. A high temperature laminated thin film capacitor as claimed in claim 1, wherein said inner core comprises at least three inner electrode layers, said first terminal electrode being connected to spaced apart said inner electrode layers with one of said inner electrode layers therebetween, said second terminal electrode being connected to the remaining said inner electrode layers.

5. A high temperature laminated thin film capacitor as claimed in claim 1 or 4, wherein one of adjacent two of said inner electrode layers protrudes in a first direction beyond an edge of said dielectric layer and the other protrudes in an opposite direction beyond an edge of said dielectric layer.

6. A method of making a high temperature laminated thin film capacitor of any one of claims 1-5, comprising:

(2) Forming an internal electrode layer on the dielectric layer;

(6) And (6) packaging the device obtained in the step (5) so as to obtain the high-temperature laminated film capacitor.

7. The method of claim 6, wherein the soluble high temperature polymer has a band gap energy of not less than 3eV.

8. The method according to claim 6, wherein the spray coating liquid is prepared by mixing a soluble high temperature polymer, an organic semiconductor and a solvent and then ultrasonically dispersing;

optionally, the trap energy of the soluble high-temperature polymer and the charge trap constructed by the organic semiconductor is not lower than 1.5eV;

optionally, the organic semiconductor comprises

At least one of (a).

9. The method according to claim 6, wherein in the step (2), the inner electrode layer is a metal foil layer, the metal foil layer is placed on the dielectric layer for cold pressing, wherein the temperature of the cold pressing is 30-60 ℃, the pressure is 10-20t, and the cold pressing is carried out in a vacuum air compressor, and the vacuum negative pressure is not higher than 80Pa; or

The inner electrode layer is a metallized electrode which is obtained by adopting high vacuum thermal resistance evaporation.

10. The method as claimed in claim 6, wherein in the step (4), the temperature of the hot press forming is not lower than 150 ℃, the time is not lower than 1h, the pressure is 1-15 t, and the hot press forming is carried out in a vacuum press, and the vacuum negative pressure is not higher than 80Pa.