Battery

Abstract

To provide a battery generating voltage without applying external force.SOLUTION: In a battery having an electrode A, an electrode B, and a dielectric body between the electrode A and the electrode B, a difference between work functions of the electrode A and the electrode B is equal to or more than 0.1 eV, and the dielectric body is a sheet consisting of a polyvinyl chloride and a plasticizer. Preferably, both of the electrode A and the electrode B are metals with a purity of 98% or above, the plasticizer includes dibutyl adipate, and content of the plasticizer in the dielectric body is equal to or more than 35 wt%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a battery, and more particularly to a battery using a dielectric. [Background technology]

[0002] As a battery using a dielectric, Patent Document 1 describes a capacitance-varying power generating element that includes a composite layer in which a plurality of ferroelectric particles are dispersed in a dielectric elastomer, and a pair of electrodes arranged above and below the composite layer, the pair of electrodes expanding and contracting in accordance with the expansion and contraction of the composite layer, in which the ferroelectric particles have crystalline orientation, are oriented and dispersed in the dielectric elastomer so that the polarization axes of the plurality of ferroelectric particles are aligned, and are polarized in the layer thickness direction of the composite layer.

[0003] Patent document 2 describes a power generation device comprising a plate-shaped first electrode, a plate-shaped second electrode arranged opposite the first electrode, and a dielectric placed on the surface of the second electrode at a distance from the first electrode so as to face the first electrode.

[0004] In the power generation device, the dielectric is placed on the surface of the second electrode with a gap between it and the first electrode, and the first electrode can repeatedly come into contact with the dielectric. Every time an external force is applied as mechanical energy, contact and separation between the dielectric and the first electrode is repeated, causing frictional charging, resulting in a potential difference between the first electrode and the second electrode, and generating electricity. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-164917 [Patent Document 2] Patent Publication No. 2021-177691 Summary of the Invention [Problem to be solved by the invention]

[0006] Patent Documents 1 and 2 describe a device that generates electricity by applying an external force to the device.

[0007] An object of the present invention is to provide a battery that generates voltage without the application of an external force. [Means for solving the problem]

[0008] The present invention has the following aspects.

[0009] [1] A battery having an electrode A, an electrode B, and a dielectric between the electrode A and the electrode B, the difference in work function between the electrode A and the electrode B is 0.1 eV or more; The battery wherein the dielectric is a sheet made of polyvinyl chloride and a plasticizer.

[0010] [2] The battery according to [1], wherein both the electrode A and the electrode B are made of metal with a purity of 98% or more.

[0011] [3] The battery according to [1] or [2], wherein the plasticizer contains dibutyl adipate.

[0012] [4] The battery according to any one of [1] to [3], wherein the content of the plasticizer in the dielectric is 35% by weight or more. [Effects of the Invention]

[0013] The battery of the present invention generates a voltage in the absence of an external force. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view of a battery according to an embodiment. [Figure 2] 1 is a graph showing measurement results in an example. [Figure 3] 1 is a graph showing measurement results in an example. [Figure 4]1 is a graph showing measurement results in an example. [Figure 5A] 1 is a graph showing measurement results in an example. [Figure 5B] 1 is a graph showing measurement results in an example. [Figure 6] 1 is a graph showing measurement results in an example. [Figure 7] 1 is a graph showing measurement results in an example. [Figure 8] 1 is a graph showing measurement results in an example. [Figure 9] 1 is a graph showing measurement results in an example. [Figure 10] 1 is a graph showing measurement results in an example. [Figure 11] 1 is a graph showing measurement results in an example. DETAILED DESCRIPTION OF THE INVENTION

[0015] As shown in Fig. 1, the battery of the present invention has an electrode A, an electrode B, and a dielectric C between the electrodes A and B. The battery of the present invention preferably has a structure in which a sheet-like dielectric C is sandwiched between the electrodes A and B.

[0016] In the battery of the present invention, a potential difference occurs between electrode A and electrode B when no external force is applied.

[0017] <Work functions of electrodes A, B, and metal> In the present invention, the difference in work function between electrode A and electrode B is 0.1 eV or more, preferably 0.12 eV or more, and particularly preferably 0.13 eV or more. The upper limit of the difference in work function between electrode A and electrode B is not particularly limited, but is, for example, 2.0 eV or less.

[0018] The work function is the minimum energy required to extract one electron from the surface of an electrode. The work function can be determined by, for example, the photoelectron method, thermionic emission method, field emission method, contact potential difference method, etc. In the present invention, when the electrode is made of pure metal (purity of 98% or more), the numerical value listed in the scientific chronology or the like can be used.

[0019] The material that can be used for electrode A and electrode B may be any conductor, but is preferably a metal. The metal may be a pure metal consisting of a single metal element, or an alloy consisting of multiple metal elements or a metal element and a non-metal element, but more preferably at least one of them is a pure metal. In this specification, pure metal refers to a metal whose main metal element content is 98% by weight or more (purity of 98% or more).

[0020] Examples of pure metals include platinum, gold, silver, aluminum, chromium, nickel, copper, tin, titanium, magnesium, calcium, barium, and sodium.

[0021] The alloys include stainless steel, brass, and the like.

[0022] It is preferable that the combination of the metal of electrode A and the metal of electrode B, which results in a difference in work function of 0.1 eV or more, contains different metal elements.

[0023] For example, a combination in which both electrode A and electrode B are pure metals, or a combination in which one electrode is a pure metal and the other electrode is an alloy, etc. can be mentioned, but it is preferable that both electrode A and electrode B are pure metals.

[0024] Examples of combinations of metals for one electrode and the other electrode include gold and aluminum, gold and zinc, gold and chromium, chromium and aluminum, titanium and aluminum, tin and aluminum, and gold and brass.

[0025] The electrode may be in the form of a plate, a thin film, a mesh, or the like. In the case of a plate or thin film, holes or slits may be provided through the electrode in the thickness direction. In the case of a thin film electrode, the electrode may be formed on a film or sheet of synthetic resin or the like. The thickness of the electrode is preferably 1 nm or more, particularly 10 nm or more, and 1000 nm or less, particularly 500 nm or less.

[0026] <Dielectric> In the present invention, the dielectric is made of polyvinyl chloride and a plasticizer. In this specification, "made of polyvinyl chloride and a plasticizer" means that 80% by weight or more of the dielectric is made of polyvinyl chloride and a plasticizer.

[0027] The dielectric is preferably a gel of a polymer material made of polyvinyl chloride and a plasticizer, and the thickness of the dielectric is preferably 0.01 mm or more, particularly 0.1 mm or more, and 5 mm or less, particularly 2 mm or less.

[0028] The polyvinyl chloride preferably has a number average molecular weight (Mn) of 70,000 or more and 200,000 or less in terms of polystyrene as measured by gel permeation chromatography (GPC).

[0029] The content of polyvinyl chloride in the dielectric is usually 5% by weight or more, preferably 8% by weight or more, more preferably 10% by weight or more, even more preferably 12% by weight or more, particularly preferably 15% by weight or more, and preferably 65% ​​by weight or less, more preferably 50% by weight or less, even more preferably 45% by weight or less, particularly preferably 40% by weight or less.

[0030] The content of the plasticizer in the dielectric is preferably 95% by weight or less, particularly 90% by weight or less, and 50% by weight or more, particularly 60% by weight or more.

[0031] As the plasticizer, an ester-based plasticizer is preferred, and although either an aromatic or aliphatic ester-based plasticizer can be used, an aliphatic ester-based plasticizer is preferred because it tends to increase the amount of power generation. Dibutyl adipate or diethylhexyl adipate is particularly preferred, with dibutyl adipate being particularly preferred.

[0032] Plasticizers other than ester-based plasticizers may be used in combination. In this case, the content of the plasticizer other than the ester-based plasticizer in the total amount of polyvinyl chloride and plasticizer is preferably 30% by weight or less, and particularly 20% by weight or less. Examples of plasticizers other than ester-based plasticizers include 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, dimethylacetamide (DMA), and diethanolamine (DEA).

[0033] In the present invention, the dielectric may contain a charge trapping agent, a heat stabilizer, etc. in addition to the plasticizer.

[0034] Examples of the charge trapping agent include tetracyanoquinodimethane, 2,4,7-trinitrofluoren-9-one, etc. The content of the charge trapping agent in the total amount of polyvinyl chloride and plasticizer is preferably 10% by weight or less, particularly preferably 5% by weight or less.

[0035] Examples of the heat stabilizer include phosphorus-based heat stabilizers, phenol-based heat stabilizers, amine-based heat stabilizers, sulfur-based heat stabilizers, and inorganic compounds of Mg, Ba, Zn, Sn, etc. The content of the heat stabilizer is preferably 5% by weight or less, and particularly preferably 3% by weight or less.

[0036] In the present invention, the dielectric is preferably a gel sheet, and both surfaces of this gel sheet are preferably flat.

[0037] <Manufacturing method of gel sheets> The double-sided flat gel sheet can be produced by the following first and second steps.

[0038] First step: A composition containing a dielectric polymer material is gelled by heating to obtain a gel.

[0039] Second step: The gel is placed in a mold and heated and pressed to obtain a gel sheet.

[0040] In the first step (gelling step), a composition containing a dielectric polymer material is mixed and heated to gel the composition and obtain a gel.

[0041] The following describes conditions suitable for producing a gel sheet using polyvinyl chloride and an ester-based plasticizer. When using these materials, the drying shrinkage of the material is very small, making it easy to obtain a desired shape.

[0042] By heating, the ester-based plasticizer is impregnated into the polyvinyl chloride and integrated. The heating temperature varies depending on the type of ester-based plasticizer, but is generally in the range of 80°C to 200°C. If the temperature is lower than 80°C, the ester-based plasticizer is less likely to impregnate the polyvinyl chloride. Also, if the heating temperature is higher than 200°C, the polyvinyl chloride is more likely to thermally decompose, which is undesirable. The heating temperature is more preferably 90°C or higher, and even more preferably 100°C or higher. Also, the heating temperature is more preferably 190°C or lower, and even more preferably 180°C or lower.

[0043] The mixing time is preferably 1 minute or more and 5 hours or less. By setting the mixing time to 1 minute or more, the impregnation of the ester-based plasticizer is sufficiently carried out, and the possibility of the ester-based plasticizer seeping out in the subsequent process is reduced. By setting the mixing time to 5 hours or less, thermal decomposition of the polyvinyl chloride is suppressed, which is preferable.

[0044] In the first step, polyvinyl chloride and an ester-based plasticizer may be charged into a batch-type container and heated while being mixed, or polyvinyl chloride and an ester-based plasticizer may be added quantitatively to a continuous kneader or the like and heated and kneaded.

[0045] In the second step (sheet forming step), the polymer gel obtained in the first step is charged into a mold and heated and pressurized to obtain a polymer gel sheet. The heating temperature varies depending on the type of ester-based plasticizer, but is generally in the range of 130°C to 200°C. By setting the temperature to 130°C or higher, the polymer gel is sufficiently plasticized and it becomes easy to form it into a sheet shape. Also, by setting the temperature to 200°C or lower, the thermal decomposition of polyvinyl chloride is suppressed.

[0046] The pressure varies depending on the type of ester-based plasticizer, but a general pressure range is acceptable. For example, it is 0.1 MPa or higher and 20 MPa or lower.

[0047] Also, during molding, it is possible to use spacers or the like to process it into an appropriate size and thickness. After forming it into an appropriate sheet by heating and pressurizing, it is gelled again by cooling.

Examples

[0048] Hereinafter, the present invention will be described with reference to examples and comparative examples.

[0049] <Overview of Examples and Comparative Examples> As in Examples 1 to 12 and Comparative Examples 1 to 3 described later, electrode A was arranged on the lower surface of the gel sheet dielectric created, and electrode B was arranged on the upper surface to fabricate a battery (hereinafter sometimes referred to as a module), and the following measurements were performed.

[0050] <I-V Measurement> I-V measurement is a method of evaluating and analyzing the power generation state by measuring the changes in the current value and voltage value while the module is in an operating state.

[0051] For each module, the amount of current when a voltage was applied from 0 volts to 1.0 volts was measured using a 2602 system source meter manufactured by Keithley Instruments, and the power generation state was evaluated.

[0052] The evaluation was based on the following three points: the amount of current (open circuit current) when the voltage is 0 volts (hereinafter referred to as Jsc), the amount of voltage (open circuit voltage) when the current is 0 amperes (hereinafter referred to as Voc), and the maximum value of the product of the current value and the voltage value (hereinafter referred to as Pmax).

[0053] <Voltage recovery measurement> Each module was connected to a multi-input data collection system NR-600 (Keyence Corporation) and a high-voltage measurement unit NR-HV04 (Keyence Corporation), and the voltage was measured.

[0054] The measurement was performed by connecting a 100Ω resistor to short-circuit for the first 5 minutes, and then measuring the voltage every minute for 20 minutes. Evaluation was based on the voltage value before short-circuiting, the voltage value 20 minutes after short-circuiting, and the ratio of these values.

[0055] <Source of metal work function> For the work function of pure metals (Au, Cr, Ti, Sn, Al), the values ​​used were from the Electrostatic Handbook (Electrostatic Association, Ohmsha, 1998). For the work function of SUS304, the value used was from the Journal of the Institute of Electrostatic Engineers, 31, 1, (2007), p. 14-19. For the work function of brass, the value used was from the Nanocoat TS Co., Ltd. website (https: / / www.nanocoat-ts.com / node / 290).

[0056] Example 1 20 parts by weight of polyvinyl chloride (1700ZI manufactured by Shin-Dai-ichi Vinyl Corporation) and 80 parts by weight of dibutyl adipate (manufactured by Daihachi Chemical Industry Co., Ltd.) were weighed into a separable flask. A stirring blade was attached to this separable flask, and the mixture was heated in an oil bath at 120°C for 30 minutes while stirring at 90 rpm, to obtain a polymer gel.

[0057] After cooling, the polymer gel was removed, and 10 g of the polymer gel was placed in a 100 mm square x 0.7 mm thick spacer using a hydraulic heating press manufactured by Toyo Seiki Seisakusho, and pressurized at 150°C with a spacer pressure of 5 MPa, followed by cooling to obtain a polymer gel sheet with a thickness of 0.63 mm.

[0058] The gel sheet-like dielectric produced as described above was cut into a piece with a diameter of 22.2 mm.

[0059] For the film with electrode A, we used a film with an electrode of 20 mm diameter and 100 nm thickness, on which gold was vapor-deposited onto a 50 μm thick polyethylene naphthalate film a (Figure 1). For the film with electrode B, we used a film with an electrode of 20 mm diameter and 100 nm thickness, on which aluminum was vapor-deposited onto a 50 μm thick polyethylene naphthalate film b (Figure 1). The film with electrode A was positioned so that electrode A was on the top side, and the film with electrode B was positioned so that electrode B was on the bottom side.

[0060] The module consisting of this dielectric and electrodes A and B was connected to the above-mentioned IV measurement device or voltage recovery measurement device, and measurements were performed. The results are shown in Table 1 and Figure 2. The voltage recovery measurement results are also shown in Figure 8.

[0061] <Example 2> Except for using diethylhexyl adipate (manufactured by Tokyo Chemical Industry Co., Ltd.) instead of dibutyl adipate, the fabrication and evaluation were carried out in the same manner as in Example 1. The results are shown in Table 1. The results of voltage recovery measurements are shown in FIG.

[0062] Example 3 The film with electrode A was an electrode film formed by vapor-depositing titanium to a diameter of 20 mm and a thickness of 100 nm on a 50 μm thick polyethylene naphthalate film. The film with electrode B was an electrode film formed by vapor-depositing aluminum to a diameter of 20 mm and a thickness of 100 nm on a 50 μm thick polyethylene naphthalate film. The fabrication and evaluation were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0063] Example 4 Except for using a polymer gel sheet with a thickness of 0.4 mm, the fabrication and evaluation were carried out in the same manner as in Example 1. The results are shown in Table 1. The results of measuring the voltage recovery are shown in FIG.

[0064] <Example 5> Except for using a polymer gel sheet with a thickness of 0.15 mm, the fabrication and evaluation were carried out in the same manner as in Example 1. The results are shown in Table 1. The results of measuring the voltage recovery are shown in FIG.

[0065] Example 6 The polymer gel sheet was prepared and evaluated in the same manner as in Example 1, except that 25 parts by weight of polyvinyl chloride and 75 parts by weight of dibutyl adipate were used. The results are shown in Table 1. The IV measurement results are shown in Figure 3. The voltage recovery measurement results are shown in Figure 11.

[0066] Example 7 The polymer gel sheet was prepared and evaluated in the same manner as in Example 1, except that 33 parts by weight of polyvinyl chloride and 67 parts by weight of dibutyl adipate were used. The results are shown in Table 1. The IV measurement results are shown in Figure 4. The voltage recovery measurement results are shown in Figure 11.

[0067] Example 8 Polyvinyl chloride and dibutyl adipate were added to tetrahydrofuran at concentrations of 2 wt % and 2 wt % and stirred at 60°C for 3 hours. The mixture was spread in a petri dish and left at room temperature until the tetrahydrofuran evaporated, resulting in a gel sheet with a thickness of 0.63 mm. This was cut into a piece with a diameter of 22.2 mm, combined with an electrode in the same manner as in Example 1, and evaluated. The results are shown in Table 1 and Figure 5A.

[0068] Example 9 A separable flask was charged with 18 parts by weight of polyvinyl chloride (1700ZI manufactured by Shin-Dai-ichi Vinyl Corporation), 71 parts by weight of dibutyl adipate (manufactured by Daihachi Chemical Industry Co., Ltd.), and 11 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide. A stirring blade was attached to the separable flask, and the mixture was heated in a 120°C oil bath for 30 minutes while stirring at 90 rpm to obtain a polymer gel. The electrode was then combined with the sample and evaluated in the same manner as in Example 1. The results are shown in Table 1 and Figure 5B. The voltage recovery measurement results are shown in Figure 8.

[0069] <Comparative Example 1 (no plasticizer added)> Polyvinyl chloride was added to tetrahydrofuran at a concentration of 4% by weight and stirred at 60°C for 3 hours. This was spread in a petri dish and left at room temperature until the tetrahydrofuran evaporated, resulting in a sheet with a thickness of 0.63 mm. This was cut into a piece with a diameter of 22.2 mm, and attached to an electrode in the same manner as in Example 1, and evaluation was carried out. The results are shown in Table 2 and FIG. 6.

[0070] <Comparative Example 2> A urethane sheet was obtained from Duranate TSS-100 (a trimer of hexamethylene diisocyanate, manufactured by Asahi Kasei Corporation), isophorone diisocyanate (weight ratio 8:2), and P-1000 (polypropylene glycol molecular weight 1000, manufactured by ADEKA Corporation). The film thickness was 0.9 mm. Except for using this urethane sheet instead of the polymer gel, the electrode was combined with the sheet and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0071] Comparative Example 3 (Difference in Work Function=0 eV) Evaluation was carried out in the same manner as in Example 1, except that an electrode-attached film in which aluminum was vapor-deposited was used for both electrode A and electrode B. The results are shown in Table 2.

[0072] Example 10 The electrode was produced and evaluated in the same manner as in Example 1, except that a SUS304 foil (not a pure metal as defined in this specification) with a diameter of 20 mm and a thickness of 0.1 mm was used as electrode B. The results are shown in Table 2.

[0073] Example 11 The fabrication and evaluation were carried out in the same manner as in Example 1, except that diisononyl phthalate (aromatic ester manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of dibutyl adipate (aliphatic ester). The results are shown in Table 2. The voltage recovery measurement results are shown in FIG.

[0074] Example 12 The polymer gel sheet was prepared and evaluated in the same manner as in Example 1, except that 67 parts by weight of polyvinyl chloride and 33 parts by weight of dibutyl adipate (a relatively small amount of plasticizer) were used. The results are shown in Table 2 and FIG. 7.

[0075] Tables 1 and 2 show the work functions of the metals and the differences in the work functions.

[0076] [Table 1]

[0077] [Table 2]

[0078] [Consideration] In Examples 1 to 12, a high voltage is generated without applying an external force to the module. In particular, Examples 1 to 9 also show excellent results in the voltage recovery test. [Explanation of symbols]

[0079] A, B electrodes C Dielectric

Claims

1. A battery having an electrode A, an electrode B, and a dielectric between the electrodes A and B, the difference in work function between the electrode A and the electrode B is 0.1 eV or more; The battery wherein the dielectric is a sheet made of polyvinyl chloride and a plasticizer.

2. 2. The battery according to claim 1, wherein both said electrode A and said electrode B are made of metal with a purity of 98% or more.

3. 10. The battery of claim 1, wherein the plasticizer comprises dibutyl adipate.

4. 4. The battery according to claim 1, wherein the content of the plasticizer in the dielectric is 35% by weight or more.

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