Electrolytic capacitor with both high-temperature durability and low-temperature stability, and manufacturing method therefor

Abstract

The present invention relates to the technical field of electrolytic capacitors, and in particular to an electrolytic capacitor with both high-temperature durability and low-temperature stability, and a manufacturing method therefor. The capacitor comprises a core, wherein the core comprises a positive electrode foil, a negative electrode foil and a separator disposed therebetween. The capacitor further comprises an electrolyte impregnated into the core, wherein the electrolyte satisfies the following exponential relationship curve: η=A×ex, where the value of A is within the range of 1.378×10-5 to 3.461×10-5; x=B÷T, the value of B being within the range of 4,298 to 5,052; η represents the viscosity of the electrolyte, with the unit thereof being mPa·s; T represents a Kelvin temperature, and the value of T is 248.15 to 363.15 K; and e is the base of the natural logarithm. By means of the present invention, an electrolyte which satisfies a specific viscosity-temperature relationship is combined with a sintered foil or a conventional etched foil, such that an electrolytic capacitor with both good high-temperature durability and good low-temperature stability can be obtained.

Description

Electrolytic capacitors that combine high-temperature durability and low-temperature stability and their manufacturing method Technical Field

[0001] This invention relates to the field of electrolytic capacitor technology, specifically to an electrolytic capacitor that combines high-temperature durability with low-temperature stability and its manufacturing method. Background Technology

[0002] In recent years, the market demand for miniaturized electrolytic capacitors has been increasing in sectors such as UPS, vehicle chargers, and server power supplies. Improving the capacitance per unit area of ​​the positive electrode material is one of the key technologies for capacitor miniaturization. Taking aluminum electrolytic capacitors as an example, the positive electrode material is produced by etching high-purity aluminum foil using chemical or electrochemical methods to increase its surface area, creating an etched foil. Then, Al2O3 is generated on the surface of the etched foil through anodic oxidation, making it the positive electrode material containing both the current collector and the dielectric. However, there are theoretical limits to increasing the surface area through etching. In recent years, there have been reports of methods to increase the specific surface area of ​​aluminum foil by sintering metal powder on the current collector surface. Relevant existing technologies include: CN 102017034 B "Electrode Material for Aluminum Electrolytic Capacitors and Method for Manufacturing the Electrode Material," etc.

[0003] Aluminum foil produced by sintering aluminum powder can increase the specific surface area by 20-40% compared to traditional etching processes. However, etched and sintered aluminum foils differ significantly in structure: sintered aluminum powder foil has a sponge-like porous structure, while traditional etched foil forms a tunnel-pore structure by etching and expanding the aluminum foil surface. Therefore, the matching requirements for the physical properties of the electrolyte (such as viscosity, conductivity, and flashover voltage) differ between these two types of aluminum foil. When the electrolyte permeates through the micropores on the aluminum foil surface, the porous structure within the sintered foil is almost completely interconnected, resulting in a faster permeation rate; whereas the micropores of traditionally etched aluminum foil have a tunnel-pore structure, with each pore isolated from the others, leading to a slower permeation rate.

[0004] Electrolytic capacitors have a relatively wide operating temperature range (e.g., -40℃ to +105℃). When operating at different ambient temperatures, the viscosity of the electrolyte inside the capacitor affects its penetration rate through the micropores in the aluminum foil, thus affecting the capacitor's self-healing properties. Therefore, the viscosity of the electrolyte system is crucial for improving the reliability of sintered foil capacitors.

[0005] As is well known, if the viscosity of the electrolyte decreases significantly at high temperatures, the excessively low electrolyte viscosity will accelerate electrolyte loss, which will adversely affect the high-temperature durability of the capacitor and thus reduce its high-temperature reliability. Conversely, if the viscosity of the electrolyte increases significantly at low temperatures, the excessively high electrolyte viscosity will hinder electrolyte flow, which will slow down the repair rate of the electrolyte. When there are defects in the capacitor, it may lead to untimely repair and ultimately cause fatal failure of the capacitor. Summary of the Invention

[0006] To address the technical challenge of balancing high-temperature durability and low-temperature stability in capacitors, this invention proposes an electrolytic capacitor and its manufacturing method that achieve both. By combining an electrolyte with a specific viscosity-temperature relationship with a sintered foil or a conventionally etched foil, this invention yields an electrolytic capacitor with excellent high-temperature durability and low-temperature stability. Furthermore, the combination of an electrolyte with a specific viscosity-temperature relationship and a sintered foil exhibits a higher capacitance compared to the combination with a conventionally etched foil.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] The present invention provides an electrolytic capacitor that combines high-temperature durability and low-temperature stability, comprising a core, wherein the core is made of a positive electrode foil, a negative electrode foil and an insulating member disposed between the two, including but not limited to wound type, stacked type, surface mount type, etc.

[0009] And an electrolyte that permeates the core;

[0010] The electrolyte satisfies the exponential relationship curve of Formula 1 as follows: η=A×e x ······Formula 1;

[0011] Where A is a constant whose value is between 1.378 × 10⁻⁶. -5 ~3.461×10 -5 Within the range; x = B ÷ T, where B is a constant whose value is in the range of 4298 to 5052;

[0012] Where η is the viscosity of the electrolyte, in mPa·s; T is the Kelvin temperature, ranging from 248.15K to 363.15K; and e is the base of the natural logarithm, approximately 2.71828.

[0013] Another aspect of the present invention provides a method for manufacturing an electrolytic capacitor that combines high-temperature durability and low-temperature stability, comprising the following steps: forming a core by stacking a positive electrode foil, a separator, and a negative electrode foil in a stacking order; immersing the core in an electrolyte; placing it inside a housing and sealing it with a sealing element; wherein the core has a lead foil at its end and is connected to a lead end outside the sealing element;

[0014] The electrolyte satisfies the exponential relationship curve of Formula 1 as follows: η=A×e x ······Formula 1;

[0015] Where A is a constant whose value is between 1.378 × 10⁻⁶. -5 ~3.461×10 -5 Within the range; x = B ÷ T, where B is a constant whose value is in the range of 4298 to 5052;

[0016] Where η is the viscosity of the electrolyte, in mPa·s; T is the Kelvin temperature, ranging from 248.15K to 363.15K; and e is the base of the natural logarithm, approximately 2.71828.

[0017] Furthermore, the exponential relationship curve satisfied by the electrolyte falls within the range of the upper limit exponential relationship curve of Formula 2 and the lower limit exponential relationship curve of Formula 3:

[0018] The upper limit exponential relationship curve is η = 1.378 × 10 -5 ×e x ...Formula 2, where x = 5052 ÷ T;

[0019] The lower limit exponential relationship curve is η = 3.461 × 10 -5 ×e x Formula 3, where x = 4298 ÷ ​​T.

[0020] That is, all electrolytes falling within the range of the upper limit exponential relationship curve of Formula 2 and the lower limit exponential relationship curve of Formula 3 can achieve a good balance between high-temperature durability and low-temperature stability, whether combined with sintered foil or conventional etched foil.

[0021] Furthermore, in Formula 1, A is a constant whose value is between 2.25 × 10⁻⁶. -5 ~3.48×10 -5 Within the range; B is a constant whose value is in the range of 4380 to 4680, the curve fitting degree R of Formula 1 is... 2 >0.998.

[0022] More preferably, the electrolyte satisfies an exponential relationship curve of η = 2.2888 × 10⁻⁶. -5 ×e x ...Formula 1-1, where x = 4658.9 ÷ T, R 2 =0.99885;

[0023] Alternatively, the electrolyte may satisfy an exponential relationship curve of η = 2.4938 × 10⁻⁶. -5 ×e x ...Formula 1-2, where x = 4674.9 ÷ T, R 2 =0.99838;

[0024] Alternatively, the electrolyte may satisfy an exponential relationship curve of η = 3.4699 × 10⁻⁶. -5 ×e x ...Formulas 1-3, where x = 4385.8 ÷ T, R 2=0.99949.

[0025] Furthermore, the positive electrode foil is an etched foil or a sintered foil.

[0026] Furthermore, the sintered foil is sintered onto the surface of the current collector by metal powder to achieve surface expansion, and the median diameter of the particles on its surface is less than or equal to 7 μm.

[0027] Furthermore, the electrolyte includes a solute and a solvent;

[0028] The solute is a polybasic acid ammonium salt and / or a polybasic acid amine salt;

[0029] The anions in the polycarboxylic acid ammonium salt and the polycarboxylic acid amine salt are each selected from polycarboxylic acid groups or polyboronic acid groups;

[0030] The cation in the polybasic ammonium acid salt is NH4. + ;

[0031] The cation in the polyacid amine salt is selected from primary amine salt NH3R. + Secondary amine salt NH2R2 + tertiary amine salt NH3R + One of them, where R represents an alkyl group with 1 to 15 carbon atoms.

[0032] Polybasic acid ammonium salts include 1,6-dodecanoic acid ammonium, azelaic acid ammonium, sebacate ammonium, pentaborate ammonium, etc.; polybasic acid amine salts include diethylamine azelaic acid, trimethylamine azelaic acid, etc.

[0033] Furthermore, the electrolyte also includes additives selected from one or more of flash stabilizers, anti-hydration agents, and hydrogen absorbers.

[0034] Beneficial technical effects:

[0035] This invention uses sintered aluminum foil with an increased expansion coefficient or conventional etched foil in combination with an electrolyte that meets specific upper and lower limit exponential relationship curves. While ensuring the miniaturization of the capacitor size, it combines the optimal viscosity and temperature relationship of the electrolyte to obtain an electrolytic capacitor that has good high-temperature durability and low-temperature stability. In addition, taking into full account the pore characteristics of the sintered foil, the combination of the electrolyte with the sintered foil that meets specific viscosity and temperature relationships has a higher capacitance than the combination with conventional etched foil. Attached Figure Description

[0036] Figure 1 is a cross-sectional view of the aluminum electrolytic capacitor manufactured in the embodiment. The decomposed state of the positive electrode foil, negative electrode foil, and the separator winding structure disposed between them, as well as the impregnated electrolyte, are not shown.

[0037] Figure 2 shows the leakage current data of each manufactured capacitor during the low-temperature power-on process;

[0038] Figure 3 shows the relationship between the viscosity η of the electrolyte in Examples 1-3 and the reciprocal of temperature T;

[0039] Figure 4 shows the relationship between the viscosity η of the electrolyte in Comparative Examples 1-2 and the reciprocal of temperature T. Detailed Implementation

[0040] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Unless otherwise specifically stated, the numerical values ​​set forth in these embodiments do not limit the scope of the invention. Techniques and methods known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques and methods should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0042] Experimental methods not specified in the following examples are generally performed according to national standards; if there is no corresponding national standard, they are performed according to general standard requirements or general methods.

[0043] It is important to note the following regarding the description of values: the statement "the value is within the range of..." does not include endpoint values; while the statements "the value is..." or "the value is..." include endpoint values.

[0044] The electrolyte used in the following aluminum electrolytic capacitors includes solvents, solutes, and additives, among which the additives include flash stabilizers, anti-hydration agents, and hydrogen absorbers.

[0045] solvent

[0046] As a solvent, its main function is to dissolve electrolytes and additives. It is preferred to use an organic solvent alone, or a mixture of an organic solvent and water can be used.

[0047] The solvents used in the following examples may be organic solvents used alone, among which polyols and lactones are representative of protic and aprotic solvents. Protic solvents include, but are not limited to, ethylene glycol, diethylene glycol, glycerol, 1,2-propanediol, 1,3-propanediol, butanol or related derivatives; aprotic solvents include, but are not limited to, γ-butyrolactone, sulfolane, methylsulfolane, N,N-dimethylformamide or related derivatives.

[0048] Organic solvents and water can also be mixed. The organic solvent-water mixture can lower the freezing point of the solvent, which can improve the low-temperature characteristics of the electrolyte to some extent.

[0049] The ratio of protic solvent, non-protic solvent, and water in the solvent system has a direct impact on the viscosity-temperature characteristics of the electrolyte.

[0050] solute

[0051] The solutes in the following examples are polybasic acid ammonium salts and / or polybasic acid amine salts, which can be obtained by acid-base neutralization reaction of organic carboxylic acids (preferably polybasic straight-chain or branched carboxylic acids) or inorganic acids and their salts (preferably boric acid complexes and their salts) with organic amines or inorganic ammonia.

[0052] The cation in the polybasic ammonium acid salt is NH4. + The anion is a polycarboxylic acid group or a polyboronic acid group. Examples of such polycarboxylic acid ammonium salts include 1,6-dodecanoic acid ammonium, azelaic acid ammonium, sebacic acid ammonium, pentaborate ammonium, etc.

[0053] The polyacid amine salt cation is a primary amine salt NH3R. + Secondary amine salt NH2R2 + Tertiary amine salt NHR3 + One of the following, wherein R represents an alkyl group with 1 to 15 carbon atoms, and the anion is a polycarboxylic acid group or a polyboronic acid group. The cation of the polycarboxylic acid amine salt can be sourced from methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, ethyldimethylamine, diethylmethylamine, etc. Examples of the polycarboxylic acid amine salt include diethylamine azelaate and trimethylamine azelaate.

[0054] These solutes can be used alone or in combination.

[0055] additive

[0056] The additives in the following examples include flash fire stabilizers, anti-hydration agents, and hydrogen absorbers.

[0057] Flashover stabilizers primarily function to stabilize the flashover voltage of the electrolyte. Examples include, but are not limited to: water-soluble organosilicones, polyacrylic acid or its derivatives, polyethylene glycol or its derivatives, polyvinyl alcohol or its derivatives, polyoxyethylene glycol or its derivatives, polysiloxanes, and nano-silica. They can be used individually or in combination of two or more.

[0058] The main function of anti-hydration agents is to inhibit the hydration reaction between the positive and negative electrode foils and water, reduce hydrogen production, and improve capacitor lifespan. Common anti-hydration agents include phosphates or phosphate esters, sugars, and aluminum silicate compounds.

[0059] Hydrogen absorbers are mainly nitro compounds, used to absorb hydrogen generated during capacitor operation, reduce internal pressure, and extend capacitor life.

[0060] Examples 1-3

[0061] The electrolyte ratios for Examples 1-3 are shown in Table 1.

[0062] Comparative Examples 1-2

[0063] The electrolyte ratios for Comparative Examples 1-2 are shown in Table 1.

[0064] Prepare the electrolyte for each case according to the mass percentage ratio of each material in Table 1 and stir evenly.

[0065] Table 1 shows the mass percentage ratio of each material in the electrolyte for each case.

[0066] Manufacturing example

[0067] The cross-sectional structure of an aluminum electrolytic capacitor is shown in Figure 1. The specific manufacturing method includes the following steps:

[0068] The positive electrode foil, the separator, and the negative electrode foil are wound together in a stacked order to form a core (in some embodiments, the core can be formed by stacking; in this invention, a wound core is used as an example; the separator is conventional electrolytic paper). The positive electrode foil is a sintered foil or a conventional etched foil. The core is then immersed in an electrolyte and placed inside an aluminum metal shell, and then sealed with a sealant. The core has lead foils at its ends, which are connected to lead terminals outside the sealant. After aging, a high-voltage aluminum electrolytic capacitor is obtained.

[0069] The capacitor made using sintered foil has a specification of 450V 1000μF, a diameter of 30mm, and a height of 60mm.

[0070] The sintered foil used was supplied by Dongyangguang. The metal powder sintered on the surface is aluminum powder with a purity greater than 99.99% and a median diameter of ≤6μm. After being energized, the aluminum foil has a withstand voltage of 650VF and a specific volume of 0.78μF / cm³. 2 .

[0071] For comparison, a capacitor with a specification of 450V 820μF was also fabricated using etched foil of the same dimensions (30mm diameter, 60mm height). The etched foil used was supplied by Jianghai, and the aluminum foil had a withstand voltage of 650VF and a specific capacitance of 0.65μF / cm². 2 .

[0072] The separator used is electrolytic paper made of wood fiber, hemp fiber, and other fibrous materials, with a density of 0.55 g / cm³. 3 ~0.85g / cm 3 The thickness is 40μm to 70μm.

[0073] Test case

[0074] 1. High-temperature durability assessment

[0075] To evaluate the impact of the electrolyte in each of the above cases on the high-temperature durability of the capacitors, tests were conducted according to the durability standard requirements of GB / T6346.1-2024 8.5: test temperature Ta = 105℃, operating voltage Vp = 450V, and ripple currents of 2.7A and 3A @ 120Hz were applied to the 450V 820μF and 450V 1000μF capacitors, respectively. The test results are shown in Table 2.

[0076] Table 2 High-Temperature Durability Data for Capacitors

[0077] As shown in Table 2, the electrolyte viscosity, when combined with the sintered or etched foil, has a significant impact on high-temperature durability. After 3000 hours of high-temperature durability testing, the capacity change of the sintered foil combined with the electrolytes of Examples 1-3 was within -5%.

[0078] In Comparative Example 1, the high-temperature durability of the electrolyte combined with the sintered foil remained unaffected. In Comparative Example 2, the capacity of the electrolyte combined with the sintered foil showed a significant decrease (-11.42%) after high-temperature durability testing, with the loss exceeding three times the initial value. In Comparative Example 2, the electrolyte combined with the etched foil also showed a loss exceeding three times the initial value after high-temperature durability testing. Because the electrolyte in Comparative Example 2 had a lower high-temperature viscosity, the changes in parameters during the 3000-hour high-temperature durability test, when combined with either the sintered or etched foil, exceeded the acceptable range, resulting in an unacceptable (NG) outcome.

[0079] Furthermore, as shown in Table 2, compared with conventional etched foil, the capacitance of the capacitor made by combining sintered foil with the electrolyte of the example is increased by at least 20%. Under the same size, the capacitance of the capacitor is increased by at least 20%, realizing the miniaturization of high-capacity products.

[0080] 2. Low-temperature stability assessment

[0081] To evaluate the impact of different electrolytes on the low-temperature stability of capacitors, the following verification experiments were conducted:

[0082] (1) Freeze the capacitor at -40℃ for 1000h;

[0083] (2) Apply a 10A@120Hz ripple current to the capacitor at -40℃.

[0084] (3) Record the changes in capacitor leakage current within 5 minutes of power-on.

[0085] Note: The verification test simulated the operating conditions of capacitors after outdoor storage in cold regions. Examples include outdoor charging stations and electric vehicles parked outdoors, which were directly put into full-load operation after long-term storage at low temperatures.

[0086] The magnitude of leakage current during power-on can be used to reflect the low-temperature stability of a capacitor. The larger the leakage current, the higher the risk of capacitor failure at low temperatures, and the worse its low-temperature stability.

[0087] The experimental results are shown in Table 3 and Figure 2.

[0088] Table 3 Leakage current data of capacitors during low-temperature power-on process.

[0089] As shown in Table 3 and Figure 2, when the sintered foil was used with the electrolytes of Examples 1-3 and Comparative Example 2, and the etched foil was used with the electrolyte of Example 1, after being frozen at -40°C for 1000 hours, a 10A ripple current was applied at -40°C, and the capacitor leakage current could be rapidly reduced to less than 1.5mA within 2 minutes.

[0090] The sintered foil and etched foil, when used with the electrolyte of Comparative Example 1, were subjected to freezing at -40°C for 1000 hours. Then, a 10A ripple current was applied at -40°C. The highest leakage currents were 96mA and 49mA, respectively, and even after 5 minutes of repair, the leakage currents remained as high as 9mA and 4mA, far exceeding the standard specification of 1.5mA. This indicates that the excessively high viscosity of the electrolyte in Comparative Example 1 at low temperatures resulted in slow ion migration, a low repair rate for defects on the positive electrode foil surface, leading to a sharp increase in the final leakage current and an increased risk of capacitor failure.

[0091] To investigate the reasons for the above differences, the viscosity of the electrolytes in each case was tested using a rotational viscometer as a function of temperature. The test method followed GB / T 22235-2008 "Determination of Viscosity of Liquids". Specific test data are shown in Table 4 below. A curve was fitted with the reciprocal of temperature T (1 / T) on the x-axis and viscosity η on the y-axis. The curve fitting equations are shown in Figures 3 and 4.

[0092] In Figures 3 and 4, the solid lines with dots represent the measured data from Table 4, while the dashed lines represent curve fitting based on the measured data for each case. For example, E+00 in Figures 3 and 4 represents 10. 0 Times, E-01 is 10 -1 Times, R 2 The goodness of fit of the curve.

[0093] Table 4. Measured data on electrolyte viscosity as a function of temperature for each case.

[0094] As shown in Table 4 and Figures 3 and 4, the curve fitting results for Examples 1-3 and Comparative Examples 1-2 are exponential relationship curves, as detailed below:

[0095] The curve fitting equation for Example 1 is: η = 2.2888 × 10 -5 ×e x ...Formula 1-1, where x = 4658.9 ÷ T(R) 2 =0.99885);

[0096] The curve fitting equation for Example 2 is: η = 2.4938 × 10 -5 ×e x ...Formula 1-2, where x = 4674.9 ÷ T(R) 2 =0.99838);

[0097] The curve fitting equation for Example 3 is: η = 3.4699 × 10 -5 ×e x ...Formulas 1-3, where x = 4385.8 ÷ T(R) 2 =0.99949);

[0098] The curve fitting equation for Comparative Example 1 is: η = 1.002 × 10 -5 ×e x ...Formula 2-1, where x = 5914 ÷ T(R) 2 =0.9997);

[0099] The curve fitting equation for Comparative Example 2 is: η = 5.690 × 10 -5 ×e x...Formula 3-1, where x = 4808 ÷ T(R) 2 =0.9997);

[0100] Based on the curve fitting results of Examples 1-3 and Comparative Examples 1-2 above, the theoretical upper limit viscosity curve and lower limit viscosity curve (i.e., R) were obtained. 2 Fitted curve for case = 1):

[0101] The equation for fitting the upper limit viscosity curve is: η = 1.378 × 10⁻⁶ -5 ×e x Formula 2, where x = 5052 ÷ T(R) 2 =1);

[0102] The equation for fitting the lower limit viscosity curve is: η = 3.461 × 10⁻⁶ -5 ×e x Formula 3, where x = 4298 ÷ ​​T(R) 2 =1);

[0103] In the curve fitting equation above: η is the viscosity of the electrolyte, in mPa·s; T is the Kelvin temperature, ranging from 248.15K to 363.15K; e is the base of the natural logarithm, approximately 2.71828.

[0104] The data and curves above show that, regardless of whether the electrolytes of Examples 1-3 are used with sintered foil or conventional etched foil, the viscosity of the electrolytes remains within the upper and lower limits of the viscosity curves in the temperature range of 248.15K to 363.15K, resulting in capacitors with good high-temperature durability and low-temperature stability. However, in Comparative Example 1, the viscosity exceeds the upper limit of the viscosity curve range in the temperature range of 248.15K to 323.15K; and in Comparative Example 2, the viscosity is below the lower limit of the viscosity curve range in the temperature range of 283.15K to 363.15K. Therefore, the electrolytes of Comparative Examples 1 and 2, when used with sintered foil, exhibit poor low-temperature stability or high-temperature durability. In Comparative Example 1, the high-temperature durability of the electrolyte combined with the sintered foil was unaffected, but the low-temperature stability was significantly affected. This was because the viscosity exceeded the upper limit of the viscosity curve range in the temperature range of 248.15K–323.15K (1 / T = 0.0031–0.0040). In Comparative Example 2, although the low-temperature stability was acceptable after combining the electrolyte with the sintered foil, the capacity showed a significant decrease (-11.42%) after high-temperature durability testing, with the loss exceeding three times the initial value. This was because the viscosity was below the lower limit of the viscosity curve range in the temperature range of 283.15K–363.15K (1 / T = 0.00275–0.0035). When the electrolyte viscosity is below the lower limit at high temperatures, the electrolyte consumption rate increases, leading to insufficient high-temperature durability of the capacitor.

[0105] Therefore, by combining an electrolyte that satisfies a specific viscosity-temperature relationship (i.e., within the range of the upper and lower viscosity curves defined in this invention) with a sintered foil or a conventional etched foil, an electrolytic capacitor that combines high-temperature durability with excellent low-temperature stability can be obtained according to this invention.

[0106] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

An electrolytic capacitor having both high-temperature durability and low-temperature stability, characterized by The device includes a core comprising a positive electrode foil, a negative electrode foil, and an insulating member disposed between the two. And an electrolyte that permeates the core; The electrolyte satisfies the exponential relationship curve of the following formula 1: η=A×e x ······Formula 1; Where A is a constant whose value is between 1.378 × 10⁻⁶. -5 ~3.461×10 -5 Within the range; x = B ÷ T, where B is a constant whose value is in the range of 4298 to 5052; Where η is the viscosity of the electrolyte, in mPa·s; T is the Kelvin temperature, ranging from 248.15K to 363.15K; and e is the base of the natural logarithm. The high-temperature durable and low-temperature stable electrolytic capacitor according to claim 1, characterized in that, The exponential relationship curve satisfied by the electrolyte falls within the range of the upper limit exponential relationship curve of Formula 2 and the lower limit exponential relationship curve of Formula 3: The upper limit exponential relationship curve is η = 1.378 × 10 -5 ×e x ...Formula 2, where x = 5052 ÷ T; The lower limit exponential relationship curve is η = 3.461 × 10 -5 ×e x ...Formula 3, where x = 4298 ÷ ​​T. The high-temperature durable and low-temperature stable electrolytic capacitor according to claim 1, wherein In Formula 1, A is a constant whose value is between 2.25 × 10⁻⁶. -5 ~3.48×10 -5 Within the range; B is a constant whose value is in the range of 4380 to 4680, the curve fitting degree R of Formula 1 is... 2 >0.

998. The high-temperature durable and low-temperature stable electrolytic capacitor according to claim 3, characterized in that, The electrolyte satisfies the exponential relationship curve η = 2.2888 × 10⁻⁶. -5 ×e x ...Formula 1-1, where x = 4658.9 ÷ T, R 2 =0.99885; Alternatively, the electrolyte may satisfy an exponential relationship curve of η = 2.4938 × 10⁻⁶. -5 ×e x ...Formula 1-2, where x = 4674.9 ÷ T, R 2 =0.99838; Alternatively, the electrolyte may satisfy an exponential relationship curve of η = 3.4699 × 10⁻⁶. -5 ×e x ...Formulas 1-3, where x = 4385.8 ÷ T, R 2 =0.99949. The high-temperature durable and low-temperature stable electrolytic capacitor according to any one of claims 1 to 4, characterized in that, The positive electrode foil is an etched foil or a sintered foil. The high-temperature durable and low-temperature stable electrolytic capacitor according to claim 5, characterized in that, The sintered foil is sintered onto the surface of the current collector by metal powder to achieve surface expansion, and the median diameter of the particles on its surface is less than or equal to 7 μm. The high-temperature durable and low-temperature stable electrolytic capacitor according to any one of claims 1 to 4, characterized in that, The electrolyte includes a solute and a solvent; The solute is a polybasic acid ammonium salt and / or a polybasic acid amine salt; The anions in the polycarboxylic acid ammonium salt and the polycarboxylic acid amine salt are each selected from polycarboxylic acid groups or polyboronic acid groups; The cation in the polybasic ammonium acid salt is NH4. + ; The cation in the polyacid amine salt is selected from primary amine salt NH3R. + Secondary amine salt NH2R2 + tertiary amine salt NH3R + One of them, where R represents an alkyl group with 1 to 15 carbon atoms. A method for manufacturing an electrolytic capacitor having both high-temperature durability and low-temperature stability, characterized by, The process includes the following steps: forming a core by stacking a positive electrode foil, an separator, and a negative electrode foil in a layered sequence; immersing the core in an electrolyte solution; placing it inside a housing and sealing it with a sealant; wherein the core has an outlet foil at its end, which is connected to an outlet end outside the sealant; The electrolyte satisfies the exponential relationship curve of the following formula 1: η=A×e x ······Formula 1; Where A is a constant whose value is between 1.378 × 10⁻⁶. -5 ~3.461×10 -5 Within the range; x = B ÷ T, where B is a constant whose value is in the range of 4298 to 5052; Where η is the viscosity of the electrolyte, in mPa·s; T is the Kelvin temperature, ranging from 248.15K to 363.15K; and e is the base of the natural logarithm. The method for manufacturing an electrolytic capacitor that combines high-temperature durability and low-temperature stability according to claim 8 is characterized in that, The exponential relationship curve satisfied by the electrolyte falls within the range of the upper limit exponential relationship curve of Formula 2 and the lower limit exponential relationship curve of Formula 3: The upper limit exponential relationship curve is η = 1.378 × 10 -5 ×e x ...Formula 2, where x = 5052 ÷ T; The lower limit exponential relationship curve is η = 3.461 × 10 -5 ×e x Formula 3, where x = 4298 ÷ ​​T. The method for manufacturing the electrolytic capacitor with both high-temperature durability and low-temperature stability according to claim 8, characterized in that, In Formula 1, A is a constant whose value is between 2.25 × 10⁻⁶. -5 ~3.48×10 -5 Within the range; B is a constant whose value is in the range of 4380 to 4680, the curve fitting degree R of Formula 1 is... 2 >0.

998. The method for manufacturing an electrolytic capacitor that combines high-temperature durability and low-temperature stability according to claim 10 is characterized in that, The electrolyte satisfies the exponential relationship curve η = 2.2888 × 10⁻⁶. -5 ×e x ...Formula 1-1, where x = 4658.9 ÷ T, R 2 =0.99885; Alternatively, the electrolyte may satisfy an exponential relationship curve of η = 2.4938 × 10⁻⁶. -5 ×e x ...Formula 1-2, where x = 4674.9 ÷ T, R 2 =0.99838; Alternatively, the electrolyte may satisfy an exponential relationship curve of η = 3.4699 × 10⁻⁶. -5 ×e x ...Formulas 1-3, where x = 4385.8 ÷ T, R 2 =0.99949. The method for manufacturing the electrolytic capacitor with both high-temperature durability and low-temperature stability according to any one of claims 8 to 11, characterized by The positive electrode foil is an etched foil or a sintered foil. The method for manufacturing the electrolytic capacitor with both high-temperature durability and low-temperature stability according to claim 12, characterized in that, The sintered foil is sintered onto the surface of the current collector by metal powder to achieve surface expansion, and the median diameter of the particles on its surface is less than or equal to 7 μm.

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