CN108878177A - The high temperature capacitors method for manufacturing thin film of high-energy density and high charge-discharge efficiencies - Google Patents

Abstract

The invention discloses a method for preparing a high-temperature capacitor film with high energy density and high charge-discharge efficiency. First, a high-dielectric constant layer and a high-insulation performance thin layer are successively deposited on the surface of a polymer capacitor film by atmospheric pressure low-temperature plasma deposition technology, and then reused. The high dielectric constant layer has the characteristics of high dielectric constant to increase the equivalent dielectric constant of the film, thereby increasing its energy density, and then use the wide energy bandgap of the high-insulation performance thin layer as a charge blocking layer, thereby effectively Inhibit the leakage current formed by the charge injection at the electrode under the action of high temperature and high electric field, and then improve the charge and discharge efficiency of the polymer capacitor film under the action of high temperature and high electric field, so as to achieve the purpose of increasing its working temperature, and finally realize the effect of high temperature and high electric field High-temperature capacitor films that still have high energy density and high charge-discharge efficiency.

Description

High-temperature capacitor film preparation method with high energy density and high charge-discharge efficiency

technical field

The invention relates to the field of polymer film capacitors, in particular to a rapid and large-scale preparation method for high-temperature capacitor films with high energy density and high charge-discharge efficiency.

Background technique

Dielectric capacitors have extremely fast charge and discharge rates (microseconds) and ultra-high power density (megawatts per kilogram). It plays a key role in high-power energy storage and pulse power systems such as industrial lasers, new energy vehicles, and advanced electromagnetic weapons. Dielectric capacitors can be mainly divided into three types according to the dielectric materials used: polymer dielectric capacitors, inorganic dielectric capacitors, and electrolytic capacitors. Among them, polymer film capacitors, which use polymer as the dielectric material, have the characteristics of light weight, good processing performance, low production cost, high dielectric strength, good self-healing property, simple integrated assembly process, and no liquid medium. At present, it has been widely used in industries such as electric vehicles, wind power, photovoltaics, lighting and railway locomotives. With the rapid development of industries such as smart grid and new energy, the demand for film capacitors is still increasing year by year. Although film capacitors have been widely used, there are still two problems at present. One is that the energy density of polymer capacitor films is low, and the other is that the working temperature of polymer capacitor films is not high.

Although the power density of film capacitors is extremely high (on the order of megawatts per kilogram), its energy density is 1-2 orders of magnitude lower than that of other energy storage technologies, such as electrochemical energy storage. The low energy density of dielectric materials has become a key bottleneck restricting the development of film capacitors. In the power system, if the energy of the capacitor is insufficient, the frequency of charging and discharging needs to be increased, which will lead to an increase in the leakage current of the capacitor, which will lead to an increase in heat generation. At the same time, insufficient energy density will inevitably lead to bulky equipment, making it difficult to solve its heat dissipation problem. These factors will make the internal temperature of the capacitor continue to rise, eventually leading to thermal instability.

At present, the working environment temperature of film capacitors in many application fields is higher than room temperature, and the electric field strength is also high. The maximum service temperature of most polymer dielectric materials is below 125°C. When the temperature gradually increases to close to the maximum service temperature, the dielectric loss of polymer dielectric materials increases sharply. Especially under the action of a high electric field, the increase in temperature will lead to an exponential increase in the internal leakage current (conductivity) of the polymer dielectric, resulting in a sharp drop in charge and discharge efficiency and energy storage density, which cannot meet the application requirements. Under high temperature and strong electric field conditions, the current high temperature polymer dielectric materials cannot meet the application requirements. There are two main problems: First, the conductance loss of polymer dielectric materials increases sharply with the increase of electric field strength under high temperature conditions, resulting in energy storage. Density dropped drastically. The second is that the large amount of conductance loss produced by the polymer dielectric under high temperature and strong electric field conditions will also cause the dielectric material to fail to work continuously and stably even in an environment far below its design temperature, which is caused by the thermal instability of the film capacitor. Effectively suppressing the leakage current of capacitor films under high temperature and high electric field conditions has become a difficult problem in the design and preparation of high-performance capacitor films.

In the field of polymer capacitor films, the main technical means to increase the energy density of capacitor films is to introduce inorganic nanoparticles with high dielectric constant into polymer capacitor films, and increase the energy density of composite materials by increasing the dielectric constant of composite materials. However, this technical method has the following problems: in order to obtain a higher dielectric constant, a higher filling amount of inorganic nanoparticles is often required, and the filling of large-capacity inorganic nanoparticles can easily cause agglomeration and cause defects inside the composite material. The huge difference in permittivity between nanoparticles with high permittivity and polymer capacitor films with low permittivity will lead to distortion of the electric field inside the composite, and the actual maximum electric field strength inside the composite is much higher than the applied electric field. The higher electrical conductivity of the high-k inorganic nanoparticles makes the leakage current of the composite higher than that of the pure polymer. The above factors lead to a decrease in the dielectric strength of the composite material, an increase in energy loss, and a decrease in charge and discharge efficiency. At the same time, the processing process of nanocomposite materials is often more complicated, requiring some special processing equipment, and some chemical reagents that will pollute the environment will also be used in the processing process.

In the field of polymer capacitor films, there are mainly two technical means to increase the working temperature of capacitor films. One is to increase the glass transition temperature of the polymer capacitor film material, thereby increasing its operating temperature. However, this technical method only improves the working temperature of the capacitor film by improving its thermal performance, and does not fundamentally solve the problem of the obvious increase of leakage current due to high temperature and high electric field. However, the increase of the leakage current will inevitably lead to severe heating inside the capacitor, which will cause thermal instability of the capacitor. The second is to introduce two-dimensional nanomaterials with high insulation properties into the capacitor dielectric material, such as nano-boron nitride sheets, and use the high insulation properties of nanoparticles to suppress the leakage current of the composite material under high temperature and high electric field. However, the problem with this technical method is that this ultra-thin two-dimensional nanomaterial must be uniformly dispersed in the polymer matrix by solution blending, and most high-temperature polymer dielectric materials are insoluble or even insoluble materials. At the same time, the compatibility between ultra-thin two-dimensional nanomaterials and most high-temperature polymer dielectric substrates is poor, and they are prone to agglomeration. This kind of ultra-thin two-dimensional nanosheets also has the problems of difficult preparation and high cost. Therefore, to solve this problem Class issues appear to be particularly important.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a method for preparing a high-temperature capacitor film with high energy density and high charge-discharge efficiency. On the basis of the existing capacitor film, a simple film surface treatment method is used to improve the polymerization rate at the same time. The energy density and charge-discharge efficiency of the physical capacitor film are designed to meet the needs of industrial applications with high energy density and high charge-discharge efficiency at high temperatures.

In order to solve the deficiencies of the prior art, the present invention provides a method for preparing a high-temperature capacitor film with high energy density and high charge-discharge efficiency. A high-dielectric constant layer and a high-temperature capacitor film are successively deposited on the surface of a polymer capacitor film by atmospheric pressure low-temperature plasma deposition Thin layer with insulating properties; use the characteristics of high dielectric constant layer with high dielectric constant to increase the equivalent dielectric constant of the film, thereby increasing its energy density; use the wide energy bandgap of the high-insulation thin layer to use it as a charge barrier layer, so as to effectively suppress the leakage current formed by the charge injection at the electrode under the action of high temperature and high electric field, thereby improving the charge and discharge efficiency of the polymer capacitor film under the action of high temperature and high electric field, and finally simultaneously improving the performance of the polymer capacitor film at high temperature. Under the aim of energy density and charge-discharge efficiency.

The further improvement lies in: the generation method of the atmospheric pressure low temperature plasma in the atmospheric pressure low temperature plasma deposition technology is a dielectric barrier discharge method, the precursor is blown into the plasma area through the carrier gas, and is excited by a high voltage power supply to generate Uniform and stable atmospheric pressure low-temperature plasma, under the action of plasma, the precursor undergoes physical and chemical changes to deposit on the surface of the capacitor film.

A further improvement is that: the atmospheric pressure low-temperature plasma deposition technology includes two gases: working gas and carrier gas, and the working gas and carrier gas are inert gas, air or a mixture thereof.

A further improvement is that: the inert gas includes helium, argon, neon, nitrogen.

A further improvement is: the high dielectric constant layer is a material with a high dielectric constant, such as tantalum pentoxide, hafnium dioxide, zirconium dioxide, and the corresponding precursor is selected corresponding to the selected high dielectric constant layer For example, the precursor of tantalum pentoxide is tantalum ethoxide, etc., the precursor of hafnium dioxide is hafnium ethoxide, etc., and the precursor of zirconium dioxide is zirconium ethoxide.

The further improvement is: the thin layer with high insulation performance is a material with a wide energy band gap, such as silicon dioxide and silicon nitride, and the corresponding precursor is selected corresponding to the selected thin layer with high insulation performance, such as silicon dioxide. The precursors are selected from ethyl orthosilicate, hexamethyldioxysilane, and octamethylcyclotetrasiloxane, and the silicon nitride precursors are selected from ammonia and monosilane.

The further improvement is that: the thickness of the thin layer with high insulating performance is 100nm-300nm.

The further improvement lies in: the high-voltage power supply in the atmospheric pressure low-temperature plasma deposition technology is microsecond pulse power supply or nanosecond pulse power supply or high-frequency high-voltage AC power supply, and the power supply parameter adjustment standard is to be able to generate stable and continuous dielectric barrier discharge.

The beneficial effects of the present invention are:

1. The present invention utilizes atmospheric pressure low-temperature plasma deposition technology to successively deposit a high dielectric constant layer and a high-insulation performance thin layer on the surface of an existing polymer capacitor film, by depositing dense and uniform high dielectric constant layers on the surface of a polymer capacitor film The high dielectric constant of the high dielectric constant layer is used to increase the energy density of the film as a whole, and the wide energy bandgap (low electron affinity, high ionization energy) of the high insulating performance thin layer is used. , as a charge blocking layer, thereby effectively suppressing the leakage current formed by charge injection at the electrode under the action of high temperature and high electric field, improving the charge and discharge efficiency of the polymer capacitor film under the action of high temperature and high electric field, and finally achieving high temperature and high The purpose of simultaneously improving the energy density and charge and discharge efficiency of polymer capacitor films under electric field conditions.

2. The atmospheric pressure low-temperature plasma deposition technology adopted in the present invention can be carried out under atmospheric pressure conditions, so it can be beneficial to large-scale production and preparation, and its low temperature characteristics also make it possible to process various polymer capacitor films, especially for Suitable for surface deposition of heat sensitive materials. The atmospheric-pressure low-temperature plasma deposition technology has no special requirements on the performance of capacitor films, and can be adapted to various polymer capacitor films, even inorganic capacitor films. The atmospheric pressure low-temperature plasma deposition technology does not affect the original performance of the capacitor film while realizing the deposition of a high dielectric constant layer and a thin layer with high insulation performance.

3. Compared with the current common technology in the field of capacitor film technology, the high-temperature capacitor film preparation method based on atmospheric pressure low-temperature plasma deposition with high energy density and high charge-discharge efficiency proposed by the present invention has simple conditions, low cost, short time consumption, and high efficiency. , low energy consumption, no pollution, fast deposition speed, and strong universality, it is very suitable for large-scale production applications.

Description of drawings

Fig. 1 is a schematic diagram of atmospheric pressure low-temperature plasma deposition generated by dielectric barrier discharge in the present invention.

Fig. 2 is a schematic structural view of a high-temperature capacitor film with high energy density and high charge-discharge efficiency prepared by the preparation method of the present invention.

Among them: 1-working gas, 2-carrier gas, 3-gas flow meter, 4-bubble bottle, 5-dielectric barrier discharge plasma region, 6-upper electrode, 7-lower electrode, 8-high voltage power supply, 9 - upper barrier dielectric plate, 10 - lower barrier dielectric plate, 11 - capacitor film to be processed.

Detailed ways

In order to deepen the understanding of the present invention, the present invention will be further described below in conjunction with the examples, which are only used to explain the present invention, and do not constitute a limitation to the protection scope of the present invention.

This embodiment provides a method for preparing a high-temperature capacitor film with high energy density and high charge-discharge efficiency. First, a high-dielectric constant layer and a high-insulation thin layer are successively deposited on the surface of a polymer capacitor film by atmospheric pressure low-temperature plasma deposition technology. The high dielectric constant layer has the characteristics of high dielectric constant to increase the equivalent dielectric constant of the film, thereby increasing its energy density; and then use the wide energy bandgap of the high-insulation thin layer as a charge blocking layer to effectively Suppress the leakage current formed by the charge injection at the electrode under the action of high temperature and high electric field, and then improve the charge and discharge efficiency of the polymer capacitor film under the action of high temperature and high electric field, and achieve the purpose of increasing its working temperature.

In the atmospheric pressure low temperature plasma deposition technology, the generation method of the atmospheric pressure low temperature plasma is a dielectric barrier discharge method. The precursor is blown into the plasma area through the carrier gas, and is excited by a high voltage power supply to generate a uniform and stable plasma between the dielectric barrier plates. Atmospheric pressure low-temperature plasma, under the action of plasma, the precursor undergoes physical and chemical changes to deposit on the surface of the capacitor film.

As shown in Figure 1, this embodiment provides a solution for dielectric barrier discharge to generate atmospheric pressure low-temperature plasma deposition, including two inert gases (helium or argon or neon or nitrogen), one of which is working gas 1, One path is the carrier gas 2, and the appropriate gas flow rate is controlled by the gas flow meter 3. The carrier gas is first passed into the bubbling bottle 4 containing the precursor of the layer to be deposited, and after the precursor is taken out, it is fully mixed with the working gas and passed into the plasma region 5 of the dielectric barrier discharge. The plasma region of the dielectric barrier discharge includes two discharge electrodes, namely an upper electrode 6 and a lower electrode 7, wherein the upper electrode is connected to a high voltage power supply 8, and the lower electrode is grounded. Between the upper and lower discharge electrodes are two barrier dielectric plates, respectively an upper barrier dielectric plate 9 and a lower barrier dielectric plate 10, wherein the upper barrier dielectric plate is closely attached to the lower surface of the upper electrode, and the lower barrier dielectric plate is closely attached to the lower electrode. of the upper surface. A discharge area is between the two blocking dielectric plates, and plasma is generated in the discharge area between the two blocking dielectric plates. The capacitor film 11 to be treated is placed in the discharge area between two dielectric barrier plates. Among them, the discharge electrode material can be selected as conductive materials such as aluminum, copper, and stainless steel, and parameters such as the size, thickness, and gap between electrodes can be adjusted as required. The high-voltage power supply can be microsecond pulse power supply, nanosecond pulse power supply, high-frequency high-voltage AC power supply, etc. The power supply parameter adjustment standard is to be able to produce stable and continuous dielectric barrier discharge. The barrier medium plate can be selected from glass, polytetrafluoroethylene, glass and other materials, and the parameters such as the size and thickness of the barrier medium plate can be adjusted according to needs. In this embodiment, the precursor of the high dielectric constant layer is selected as tantalum ethoxide, and the high dielectric constant layer of tantalum pentoxide can be deposited on the surface of the polymer capacitor film through the dielectric barrier discharge atmospheric pressure low-temperature plasma deposition technology. Then replace the precursor with a high-insulation performance thin-layer precursor orthosilicate ethyl ester, and then deposit silicon dioxide on the surface of the above-mentioned film with a high dielectric constant layer deposited by the dielectric barrier discharge atmospheric pressure low-temperature plasma deposition technology. Floor.

The present invention utilizes atmospheric pressure low-temperature plasma deposition technology to successively deposit a high dielectric constant layer and a high insulating performance thin layer on the surface of an existing polymer capacitor film, by depositing a dense, uniform high dielectric constant layer and Thin layer with high insulating performance, using the high dielectric constant of the high dielectric constant layer to increase the energy density of the film as a whole, using the characteristics of wide energy bandgap (low electron affinity, high ionization energy) of the high insulating performance thin layer, the As a charge blocking layer, it can effectively suppress the leakage current formed by the charge injection at the electrode under the action of high temperature and high electric field, improve the charge and discharge efficiency of the polymer capacitor film under the action of high temperature and high electric field, and finally achieve high temperature and high electric field The purpose of improving the energy density and charge and discharge efficiency of the polymer capacitor film at the same time.

The atmospheric pressure low-temperature plasma deposition technology adopted in the present invention can be carried out under atmospheric pressure conditions, so it can be beneficial to large-scale production and preparation, and its low temperature characteristics also make it possible to process various polymer capacitor films, especially suitable for Surface deposition of heat sensitive materials. The atmospheric-pressure low-temperature plasma deposition technology has no special requirements on the performance of capacitor films, and can be adapted to various polymer capacitor films, even inorganic capacitor films. The atmospheric pressure low-temperature plasma deposition technology does not affect the original performance of the capacitor film while realizing the deposition of a high dielectric constant layer and a thin layer with high insulation performance.

Compared with the current common technology in the field of capacitor film technology, the high-temperature capacitor film preparation method based on atmospheric pressure low-temperature plasma deposition with high energy density and high charge-discharge efficiency proposed by the present invention has simple conditions, low cost, short time-consuming, high efficiency, and energy efficiency. The characteristics of low consumption, no pollution, fast deposition speed, and strong universality are very suitable for large-scale production applications.

Claims (9)

1. the high temperature capacitors method for manufacturing thin film of a kind of high-energy density and high charge-discharge efficiencies, it is characterised in that：By big Air pressure low-temperature plasma deposition technique is in the successive deposit high dielectric constant layer of polymer capacitors film surface and high insulating property Thin layer；Has the characteristics that high dielectric constant using high dielectric constant layer to improve the effective dielectric constant of film, to improve it Energy density；Using the wide bandgap of high insulating property thin layer, as electric charge barrier layer, to effectively inhibit the high electricity of high temperature The leakage current formed under field action due to the charge injection at electrode, and then polymer capacitors film is improved in high temperature height Efficiency for charge-discharge under electric field action is finally reached while improving polymer capacitors film energy density and charge and discharge at high temperature The purpose of electrical efficiency.

2. the high temperature capacitors method for manufacturing thin film of high-energy density according to claim 1 and high charge-discharge efficiencies, It is characterized in that：The producing method of atmos low-temperature plasma in the atmos low-temperature plasma deposition technique is medium resistance Discharge mode is kept off, presoma is blown by plasma slab by carrier gas, is motivated through high voltage power supply, is generated between dielectric impedance plate Uniform and stable atmos low-temperature plasma, under action of plasma, physics, chemical change occur for presoma in electricity Container film surface is deposited.

3. the high temperature capacitors method for manufacturing thin film of high-energy density according to claim 2 and high charge-discharge efficiencies, It is characterized in that：It include two-way gas in the atmos low-temperature plasma deposition technique：Working gas and carrier gas, the work gas Body and carrier gas are or mixtures thereof inert gas, air.

4. the high temperature capacitors method for manufacturing thin film of high-energy density according to claim 3 and high charge-discharge efficiencies, It is characterized in that：The inert gas includes helium, argon gas, neon, nitrogen.

5. the high temperature capacitors method for manufacturing thin film of high-energy density according to claim 1 and high charge-discharge efficiencies, It is characterized in that：The high dielectric constant layer is the material with high dielectric constant, such as tantalum pentoxide, hafnium oxide, titanium dioxide Zirconium, and correspond to selected high dielectric constant layer and select corresponding presoma, as the presoma of tantalum pentoxide is selected as second Alcohol tantalum etc., the presoma of hafnium oxide are selected as ethyl alcohol hafnium etc., and the presoma of zirconium dioxide is selected as ethyl alcohol zirconium.

6. the high temperature capacitors method for manufacturing thin film of high-energy density according to claim 5 and high charge-discharge efficiencies, It is characterized in that：The high dielectric constant layer thickness is at 100nm-3 μm.

7. the high temperature capacitors method for manufacturing thin film of high-energy density according to claim 1 and high charge-discharge efficiencies, It is characterized in that：The high insulating property thin layer is the thin layer with wide bandgap, such as silica, silicon nitride, is corresponded to selected The high insulating property thin layer selected selects corresponding presoma, as the presoma of silica is selected as ethyl orthosilicate, hexamethyl Dioxy silane, octamethylcy-clotetrasiloxane, silicon nitride precursor body are selected as ammonia and monosilane.

8. the high temperature capacitors method for manufacturing thin film of high-energy density according to claim 7 and high charge-discharge efficiencies, It is characterized in that：The high insulating property thickness of thin layer is in 100nm-300nm.

9. the high temperature capacitors method for manufacturing thin film of high-energy density according to claim 1 and high charge-discharge efficiencies, It is characterized in that：The atmos low-temperature plasma deposition technique mesohigh power supply be microsecond pulse power supply or nanosecond pulse power supply or High frequency and high voltage power supply, power parameter adjustment criteria are that can generate steady and sustained dielectric barrier discharge.