Preparation method of special aluminum electrolytic capacitor for low-temperature-resistant detonator initiator

Abstract

The application provides a preparation method of a low-temperature-resistant detonator igniter special aluminum electrolytic capacitor, and the preparation method comprises the following steps: riveting positive foil and negative foil after cutting, and riveting positive guide needle and negative guide needle; winding the electrolytic paper into a core package between the riveted positive foil and negative foil, injecting electrolyte into the core package, sealing the core package in an aluminum shell by using glue particles, and obtaining a semi-finished product capacitor; cleaning the semi-finished product capacitor, sleeving a sleeve, and sequentially performing primary aging selection, secondary aging selection, appearance observation and inspection, thereby obtaining the final product. The preparation method of the low-temperature-resistant detonator igniter special aluminum electrolytic capacitor has simple production process, common materials and low price, and the prepared aluminum electrolytic capacitor has excellent electrical performance, wide working temperature range and small size.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aluminum electrolytic capacitors, and particularly relates to a preparation method of a special aluminum electrolytic capacitor for low-temperature-resistant detonator igniters. BACKGROUND

[0002] At present, the continuous development and improvement of electronic detonator technology has posed a technical threat to electric and non-electric detonators. Electronic detonators realize high-precision initiation timing control, and provide new technical support for accurate blasting design, blasting effect control, blasting mechanism and process simulation research. The technical superiority of electronic detonators has been increasingly recognized in the global blasting industry. In particular, with the continuous decrease in the production cost of new-type electronic detonators, the production and application of electronic detonators have been expanded from the early rare and precious mineral mining field to ordinary mines and quarries, fixed-point blasting of high-speed rail and highway routes.

[0003] The safety problem is still generally concerned by users of electronic detonators. The safety of electronic detonators is mainly determined by the ignition delay circuit thereof. The charging transistor and the discharging transistor constitute the main ignition circuit of the system, and the electrolytic capacitor discharges under the control of the microcontroller through the ignition transistor to ignite the ignition head.

[0004] At present, tantalum electrolytic capacitors are used. The tantalum electrolytic capacitor has the characteristics of small size, long service life, high and low temperature resistance, and excellent filtering performance. In addition, the melting point of tantalum is high, and the parameter performance of tantalum is not easily affected by external temperature. However, the tantalum capacitor will explode and catch fire when the ripple current exceeds the rated value, and the tantalum capacitor has poor overcurrent resistance and is very easy to catch fire. Tantalum metal is a non-renewable mineral resource, and the global tantalum ore content is very limited. In addition, because tantalum is resistant to high temperature and corrosion, the processing cost is high, and the price of tantalum capacitors is high.

[0005] Therefore, it is necessary to develop a special aluminum electrolytic capacitor for low-temperature-resistant detonator igniters. The aluminum electrolytic capacitor has excellent electrical performance, a wide working temperature range, and a small size, and can be applied to detonator igniters to replace tantalum capacitors. SUMMARY

[0006] The application aims to provide a preparation method of a special aluminum electrolytic capacitor for low-temperature-resistant detonator igniters. The electrical performance and working temperature range of the capacitor are improved by optimizing the structure of the capacitor and the preparation process of each component, and the capacitor has a small size and low cost.

[0007] The application discloses a preparation method of a special aluminum electrolytic capacitor for low-temperature-resistant detonator igniters.

[0008] The preparation method of the positive foil comprises the following steps: taking high-purity aluminum foil, pre-treating the aluminum foil, performing hole and expansion processing, and drying to obtain the positive foil.

[0009] The specific pre-treatment steps are as follows: the high-purity aluminum foil is immersed in the immersion solution for 10-20 s and then taken out and dried.

[0010] Preferably, the immersion solution is an acrylic resin aqueous solution.

[0011] Preferably, the mass fraction of the acrylic resin in the acrylic resin aqueous solution is 0.5%-2%.

[0012] Preferably, the solid content of the acrylic resin is 39%-41wt%, and the viscosity is less than 200 cps.

[0013] In some preferred schemes, the water-based acrylic resin is purchased from Guangdong Xindong New Material Technology.

[0014] The specific hole forming step is as follows: the immersed aluminum foil is taken as an anode, graphite is taken as a cathode, the aluminum foil is placed into a hole forming solution, and hole forming processing is performed at a temperature of 80-90 DEG C and a current density of 0.1-0.2 A / cm 2 for 2-3 min; after the processing, the aluminum foil is rinsed with deionized water and dried.

[0015] Preferably, the hole forming solution is a mixed acid and a metal ion aqueous solution.

[0016] Preferably, the concentration of the mixed acid in the hole forming solution is 5-7 mol / L.

[0017] Preferably, the mixed acid is sulfuric acid and hydrochloric acid, and the molar ratio is (3-5):1.

[0018] Preferably, the content of the metal ion in the hole forming solution is 50-150 ppm.

[0019] Preferably, the metal ion comprises one or more of iron ions, ferrous ions, copper ions and zinc ions.

[0020] The specific step of the hole expansion is: taking the aluminum foil after the hole forming as an anode, taking graphite as a cathode, and putting into a hole expansion solution, and carrying out the hole expansion treatment under the conditions of temperature of 80-90 DEG C, current density of 0.1-0.2 A / cm 2 After the end, the aluminum foil is rinsed with deionized water and air dried.

[0021] Preferably, the hole expansion solution is hydrochloric acid aqueous solution.

[0022] Preferably, the concentration of hydrochloric acid in the hydrochloric acid aqueous solution is 0.8-1.2 mol / L.

[0023] The inventor finds that the specific method is used to treat the high-purity aluminum foil to obtain the positive electrode foil, which can improve the specific capacity of the positive electrode foil, thereby improving the capacitance of the capacitor, and reducing the leakage current. This may be because the specific hole forming and hole expansion process, on the one hand, the mixed acid system of sulfuric acid and hydrochloric acid in the hole forming solution and the metal ions of specific concentration jointly act on the surface of the aluminum foil to form the initial corrosion hole, the hydrogen ion provided by the sulfuric acid promotes the corrosion, the chloride ion in the hydrochloric acid has the de-passivation effect to accelerate the formation of the pitting corrosion, the addition of the metal ions can occupy the corrosion site of Cl- to a certain extent, reduce the useless corrosion of Cl-, improve the corrosion morphology of the aluminum foil, and further refine the corrosion hole structure, and help the discharge of Al3+ in the tunnel hole to make the tunnel hole continue to grow and improve the uniformity of the hole distribution. On the other hand, the hole expansion treatment makes the initial corrosion hole further expand and connect with each other to form a more complex tunnel hole structure, which greatly increases the specific surface area of the aluminum foil, provides more charge storage space for the capacitor, thereby improving the capacitance of the capacitor, and the corrosion hole with uniform distribution and moderate depth helps to reduce the generation of the leakage current.

[0024] Preferably, the negative electrode foil is high-purity copper foil.

[0025] The positive electrode foil prepared by the application is compounded with the high-purity negative electrode foil, which can comprehensively improve the composite specific capacity, thereby making the device with the same energy density smaller, and being suitable for application in electronic detonator igniter.

[0026] The positive guide needle and the negative guide needle are tin-plated copper-clad steel wire (CP wire).

[0027] The number of layers of the electrolytic paper is 1 layer.

[0028] The conditions of the first aging selection are: using the constant current and constant voltage mode, applying the constant current of 60-70 mu A, waiting for the voltage to reach 440-460 V, and then constant voltage aging for 2-6 h. After the first aging, the leakage current is tested, and the leakage current of less than or equal to 40 mu A is qualified to enter the next step.

[0029] The secondary aging selection condition is: using pulse and constant voltage mode, charging 120s, discharging 10s as a pulse, aging 1-2h under 440-460V voltage, testing the leakage current after secondary aging, ≤40μA is qualified, entering the next step.

[0030] The inventors found that selecting two different aging selection steps can ensure that the finally screened capacitors have high stability, small leakage current and reliable quality. This may be because on the one hand, the first selection uses constant current and constant voltage aging, which can not only initially screen out capacitors with potential leakage or short circuit problems, or capacitors that cannot withstand high voltage, but also help to activate the self-repairing mechanism inside the capacitor and reduce the leakage phenomenon; on the other hand, the second selection uses pulse and constant voltage aging, which not only tests the charge and discharge performance of the capacitor, but also accelerates the aging process inside the capacitor to some extent, thereby more quickly exposing potential performance problems. At the same time, it is also helpful to further activate the self-repairing mechanism inside the capacitor and reduce the leakage phenomenon. The combination of the two aging methods can repair and solidify the damaged aluminum oxide in the manufacturing process and improve its parameters, insulation properties, etc.; at the same time, test and remove abnormal quality products.

[0031] The preparation method of the electrolytic paper comprises the following steps: taking bleached kraft softwood pulp, soaking in deionized water, beating to a beating degree of 85-90°SR, diluting with first deionized water to obtain liquid one; taking modified cellulose fibers, dispersing in second deionized water, adding to liquid one, homogenizing for 2-4h, making wet paper, drying the wet paper by pressing, and calendering to obtain the electrolytic paper.

[0032] Preferably, the average fiber length of the bleached kraft softwood pulp is 2.8-3.2mm, the average fiber roughness is 18-20mg / 100g, the average fiber content is (2.8-3.0)×10 6 g, and the viscosity is 18-22CP; further preferably, the average fiber length of the bleached kraft softwood pulp is 3.1mm, the average fiber roughness is 20mg / 100g, the average fiber content is 2.9×10 6 g, and the viscosity is 20CP.

[0033] In some preferred embodiments, the bleached kraft softwood pulp is purchased from Goodstone 100 in Canada.

[0034] The inventors found that the electrolytic paper prepared by using specific bleached sulfate softwood pulp as raw material can reduce the internal resistance of the capacitor and improve the low-temperature resistance. This may be because the specific bleached sulfate softwood pulp with longer fibers and lower average fiber content is used as the raw material of the electrolytic paper, and the specific pressing pressure is used to prepare the electrolytic paper with low density and developed pores. The electrolytic paper not only helps the flow of electrolyte and the transmission of ions, thereby reducing the internal resistance of the capacitor, but also helps to maintain the flowability of the electrolyte when the flowability of the electrolyte decreases at low temperature, thereby improving the low-temperature resistance of the capacitor. In addition, by controlling the thickness of the electrolytic paper, the ion transmission can be achieved while avoiding affecting the insulation and thus affecting the leakage current. However, the structure of the electrolytic paper is not very stable at extreme temperatures, which affects the performance of the capacitor.

[0035] Preferably, the mass concentration of the liquid in the absolute dry pulp is 1.5-2.5 g / L.

[0036] Preferably, the addition amount of the modified cellulose fiber is 1%-3% of the mass of the absolute dry pulp.

[0037] Preferably, the mass ratio of the modified cellulose fiber to the second deionized water is 1:(100-200); further preferably, 1:150.

[0038] The preparation method of the modified cellulose fiber comprises the following steps: uniformly dispersing the cellulose fiber in the third deionized water, adding a modifier, adjusting the pH of the system to be stable at 10-10.5, reacting for 3-5 h, washing the product to be neutral with deionized water, and drying to obtain the product.

[0039] Preferably, the cellulose fiber comprises a first cellulose fiber and a second cellulose fiber.

[0040] Preferably, the length of the first cellulose fiber is 0.1-1 nm, and the diameter is 100-1000 nm.

[0041] Preferably, the length of the second cellulose fiber is 1-20 μm, and the diameter is 20-80 nm.

[0042] In some preferred embodiments, the first cellulose fiber and the second cellulose fiber are both purchased from MFC and CNF-H1 produced by Zhejiang Jingjiahao Green Nanometer Material Co., Ltd.

[0043] Preferably, the mass ratio of the first cellulose fiber to the second cellulose fiber is (2-4):1; further preferably, 3:1.

[0044] Preferably, the mass ratio of the cellulose fiber to the third deionized water is 1:(150-250); further preferably, 1:200.

[0045] Preferably, the modifier is 2,2,6,6-tetramethylpiperidine oxide, sodium bromide and sodium hypochlorite.

[0046] Preferably, the mass ratio of the 2,2,6,6-tetramethylpiperidine oxide, sodium bromide and sodium hypochlorite is 1:(4-6):(290-310); further preferably, 1:10:300.

[0047] Preferably, the addition amount of the modifier is 5-8 times of the mass of the cellulose fibers.

[0048] Preferably, the basis weight of the wet paper is 24-28 g / m 2 .

[0049] Preferably, the calendering treatment condition is: temperature 62-66℃, pressure 0.15-0.2 kgf / cm 2 .

[0050] Preferably, the thickness of the electrolytic paper is 35-45 μm.

[0051] The inventors found that adding two different cellulose fibers to the bleached kraft softwood pulp and modifying them can reduce the internal resistance of the capacitor while improving the stability of the capacitor at high and low temperatures. This may be because the introduction of two cellulose fibers with different aspect ratios to the bleached kraft softwood pulp can increase the complexity and diversity of the internal fiber structure of the electrolytic paper. Long fibers can provide good conductive channels and promote the rapid transmission of electric charges within the electrolytic paper; short fibers can fill the gaps between long fibers and form a more compact fiber network, improving the density and strength of the electrolytic paper. The synergistic effect of long and short fibers enables the electrolytic paper to maintain high capacity while also having good stability and durability. During the mixing process, the fibers of the bleached kraft softwood pulp interact with the two cellulose fibers with different aspect ratios, which helps to enhance the bonding force between the fibers, so that the electrolytic paper is not easily deformed or broken when subjected to temperature changes, thereby maintaining stable capacitance performance. By modifying the cellulose fibers, not only can the dispersibility of the cellulose fibers in the bleached kraft softwood pulp be improved, thereby further improving the stability of the electrolytic paper, but also the absorption and retention capacity of the electrolytic paper for the electrolyte can be improved, further enhancing the capacitance performance.

[0052] In some preferred schemes, the combination of high-conductivity CP wire needle and low-density electrolytic paper can reduce the equivalent series resistance of the capacitor. This is because the combination has a synergistic effect, the high-conductivity CP wire needle is responsible for efficient current transmission, reducing resistance heat effect and energy loss; while the low-density electrolytic paper provides good insulation performance, protects the circuit from external interference and damage, and the two work together to improve the overall performance of the capacitor. At the same time, because the high-conductivity CP wire needle reduces the resistance in the current transmission process, and the low-density electrolytic paper reduces the dielectric loss and insulation resistance heat effect of the capacitor, the combined effect of the two can significantly reduce the ESR value of the capacitor, thereby improving the stability of the capacitor.

[0053] Preferably, the electrolyte comprises lithium bis(trifluoromethanesulfonyl)imide and an organic solvent.

[0054] Preferably, the concentration of lithium bis(trifluoromethanesulfonyl)imide in the electrolyte is 0.5-1.5 mol / L.

[0055] Preferably, the organic solvent is γ-butyrolactone, ethylene carbonate, propylene carbonate, or methyl acetate.

[0056] Preferably, the volume fraction of γ-butyrolactone in the organic solvent is 50%-60%.

[0057] Preferably, the volume ratio of ethylene carbonate, propylene carbonate, and methyl acetate is 1:(1-3):(0.5-2); further preferably, 1:2:1.

[0058] The inventors have found that the use of specific organic solvents and lithium salts to prepare electrolytes can improve the high-temperature and low-temperature resistance of capacitors, widen the operating temperature range, and also increase the capacitance. γ-butyrolactone solution has high stability and stable chemical structure at high and low temperatures, but its conductivity is low. However, through the synergistic effect of the four organic solvents, on the one hand, ethylene carbonate and propylene carbonate have good mutual solubility and synergistic effect, the addition of ethylene carbonate can reduce the melting point of propylene carbonate and improve the low-temperature performance of the electrolyte, and the mixture of the two can form a stable solvation structure, which is conducive to ion transmission and storage; on the other hand, methyl acetate can greatly improve the low conductivity problem of pure γ-butyrolactone in the γ-butyrolactone solvent system, reduce the internal resistance of the capacitor, and also retain the advantages of good stability and high voltage resistance of γ-butyrolactone, reduce the decomposition of the electrolyte and the corrosion of the electrode, thereby reducing the leakage current. However, because methyl acetate has relatively poor high-temperature and low-temperature resistance, its addition amount needs to be controlled.

[0059] Compared with the prior art, the advantages and beneficial effects of the present application are:

[0060] 1. The application provides a preparation method of a low-temperature-resistant detonator igniter special aluminum electrolytic capacitor, which has simple production process, common material and low price, and has excellent electrical performance, wide working temperature range and small volume.

[0061] 2. The application selects a specific method to treat high-purity aluminum foil to obtain a positive foil, which can improve the specific capacity of the positive foil, thereby improving the capacitance of the capacitor and reducing the leakage current; meanwhile, the positive foil prepared by the application is compounded with a high-purity negative foil, which can comprehensively improve the composite specific capacity, so that devices with the same energy density can be made smaller, and are suitable for application in electronic detonator igniters.

[0062] 3. The application selects two different aging selection steps, which can ensure that the finally screened capacitor has high stability, small leakage current and reliable quality.

[0063] 4. The application uses high-conductivity CP wire guide pins and low-density electrolytic paper to reduce the ESR value of the product.

[0064] 5. The application selects specific organic solvents and lithium salts to prepare electrolyte, which can improve the high-temperature and low-temperature resistance of the capacitor, widen the working temperature range, and also improve the capacitance.

[0065] 6. The application uses high-purity guide pins and aluminum stems to pressurize and form, which ensures the stability of the product parameter performance. DETAILED DESCRIPTION

[0066] The technical solutions in the embodiments of the application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0067] The raw materials used in the application are commercially available, specifically:

[0068] The solid content of the acrylic resin is 39-41wt%, and the viscosity is <200cps, which is purchased from Guangdong Xindong New Material Technology.

[0069] The average length of the bleached sulfate needle leaf pulp fibers is 3.1mm, the average roughness of the fibers is 20mg / 100g, and the average content of the fibers is 2.9x10 6 Root / g, and the viscosity is 20CP, which is purchased from Canada Haosheng 100.

[0070] The first cellulose fiber has a length of 0.1-1 nm and a diameter of 100-1000 nm; the second cellulose fiber has a length of 1-20 μm and a diameter of 20-80 nm; both are purchased from Zhejiang Jinjiahao Green Nanometer Material Co., Ltd., MFC, CNF-H1.

[0071] Example 1

[0072] The embodiment provides a preparation method of a low-temperature-resistant detonator igniter special aluminum electrolytic capacitor, and steps are as follows: riveting positive foil and negative foil after cutting; winding 1 layer of electrolytic paper between the riveted positive foil and negative foil to form a core package, injecting electrolyte into the core package, sealing the core package in an aluminum shell by using colloidal particles to seal the opening, and obtaining a semi-finished product capacitor; sleeving the semi-finished product capacitor after cleaning, and sequentially performing primary aging selection, secondary aging selection, appearance observation and inspection, so that the low-temperature-resistant detonator igniter special aluminum electrolytic capacitor is obtained.

[0073] The preparation method of the positive foil comprises the following steps: pretreating high-purity aluminum foil, performing hole forming and hole expanding treatment, and air-drying to obtain the positive foil.

[0074] The specific steps of the pretreatment are as follows: immersing the high-purity aluminum foil in an immersion solution for 15 s, and air-drying.

[0075] The immersion solution is an acrylic resin aqueous solution, and the mass fraction of the acrylic resin is 1%.

[0076] The specific steps of the hole forming are as follows: taking the immersed aluminum foil as an anode, taking graphite as a cathode, placing the aluminum foil in a hole forming solution, and performing hole forming treatment under the conditions that the temperature is 85 ℃ and the current density is 0.15 A / cm 2 for 2.5 min; and then rinsing the aluminum foil with deionized water and air-drying.

[0077] The hole forming solution is a mixed acid and a metal ion aqueous solution, wherein the concentration of the mixed acid is 6 mol / L, and the content of the metal ion is 100 ppm.

[0078] The mixed acid is sulfuric acid and hydrochloric acid, and the molar ratio is 4:1.

[0079] The metal ion in the hole forming solution is an iron ion.

[0080] The specific steps of the hole expanding are as follows: taking the aluminum foil after the hole forming as an anode, taking graphite as a cathode, placing the aluminum foil in a hole expanding solution, and performing hole expanding treatment under the conditions that the temperature is 85 ℃ and the current density is 0.15 A / cm 2 for 6 min; and then rinsing the aluminum foil with deionized water and air-drying.

[0081] The hole expanding solution is a hydrochloric acid aqueous solution, and the concentration of the hydrochloric acid is 1 mol / L.

[0082] The negative electrode foil is a high-purity copper foil.

[0083] The first aging selection condition is that constant current and constant voltage are adopted, a constant current of 65 μA is applied, and after the voltage reaches 450 V, constant voltage aging is performed for 4 h. After the first aging, the leakage current is tested, and if it is less than or equal to 40 μA, it is qualified and enters the next step.

[0084] The second aging selection condition is that pulse and constant voltage are adopted, 120 s of charging and 10 s of discharging are a pulse, and aging is performed for 1.5 h under a voltage of 450 V. After the second aging, the leakage current is tested, and if it is less than or equal to 40 μA, it is qualified and enters the next step.

[0085] The preparation method of the electrolytic paper comprises the following steps: bleached kraft softwood pulp is soaked in deionized water, and then beaten to a beating degree of 88°SR. After being diluted with first deionized water, liquid one is obtained. Modified cellulose fibers are dispersed in second deionized water, and then added to liquid one. After homogenization for 3 h, wet paper is made, and then the wet paper is pressed, dried, and calendered to obtain electrolytic paper.

[0086] The mass concentration of the absolutely dry pulp in the liquid one is 2 g / L.

[0087] The addition amount of the modified cellulose fibers is 2% of the mass of the absolutely dry pulp.

[0088] The mass ratio of the modified cellulose fibers to the second deionized water is 1:150.

[0089] The preparation method of the modified cellulose fibers comprises the following steps: cellulose fibers are uniformly dispersed in third deionized water, a modifier is added, the pH of the system is adjusted to about 10.3, and reaction is performed for 4 h. Then, the product is washed with deionized water until it is neutral, and then dried to obtain the modified cellulose fibers.

[0090] The cellulose fibers are first cellulose fibers and second cellulose fibers, and the mass ratio is 3:1.

[0091] The mass ratio of the cellulose fibers to the third deionized water is 1:200.

[0092] The modifier is 2,2,6,6-tetramethylpiperidine oxide, sodium bromide, and sodium hypochlorite, and the mass ratio is 1:10:300.

[0093] The addition amount of the modifier is 6 times the mass of the cellulose fibers.

[0094] The wet paper is made with a basis weight of 25 g / m 2 .

[0095] The calendering treatment condition is that the temperature is 64°C, and the pressure is 0.18 kgf / cm 2 .

[0096] The thickness of the electrolytic paper is 40 μm.

[0097] The electrolyte comprises lithium bis-trifluoromethanesulfonimide, an organic solvent.

[0098] The concentration of the lithium bis-trifluoromethanesulfonimide in the electrolyte is 1 mol / L.

[0099] The organic solvent is γ-butyrolactone, ethylene carbonate, propylene carbonate, methyl acetate.

[0100] The volume fraction of the γ-butyrolactone in the organic solvent is 55%.

[0101] The volume ratio of the ethylene carbonate, propylene carbonate, methyl acetate is 1:2:1.

[0102] Example 2

[0103] The difference between this example and Example 1 is that the conditions for the first aging selection are as follows: the constant current and constant voltage mode is used, the constant current is 65 μA, and after the voltage reaches 450 V, the constant voltage aging is performed for 3 h, the leakage current is tested after the first aging, and ≤40 μA is qualified to enter the next step.

[0104] The conditions for the second aging selection are as follows: the pulse and constant voltage mode is used, the charging is 120 s and the discharging is 10 s as one pulse, the aging is performed for 1.5 h under the voltage of 450 V, the leakage current is tested after the second aging, and ≤40 μA is qualified to enter the next step.

[0105] Example 3

[0106] The difference between this example and Example 1 is that the metal ion is ferrous ion.

[0107] Comparative Example 1

[0108] The difference between this comparative example and Example 1 is that the pore-forming solution is a mixed acid aqueous solution, and the concentration of the mixed acid is 6 mol / L.

[0109] Comparative Example 2

[0110] The difference between this comparative example and Example 1 is that the mixed acid is replaced by sulfuric acid, and the concentration in the pore-forming solution is 6 mol / L.

[0111] Comparative Example 3

[0112] The difference between this comparative example and Example 1 is that the bleached sulfate softwood pulp has an average fiber length of 2.9 mm, an average fiber roughness of 17 mg / 100 g, and an average fiber content of 3.9 x 10 6 g, which is purchased from GoodSound400, Canada.

[0113] Comparative Example 4

[0114] The difference between the present comparative example and Example 1 is that the cellulose fiber is the first cellulose fiber.

[0115] Comparative Example 5

[0116] The difference between the present comparative example and Example 1 is that the modifier is sodium bromide and sodium hypochlorite; and the mass ratio of the sodium bromide and the sodium hypochlorite is 1:30.

[0117] Comparative Example 6

[0118] The difference between the present comparative example and Example 1 is that the preparation method of the low-temperature-resistant detonator igniter special aluminum electrolytic capacitor is as follows: the positive foil and the negative foil are cut and riveted with the CP wire, respectively; 1 layer of electrolytic paper is placed between the riveted positive foil and negative foil to form a core package, electrolyte is injected into the core package, and the core package is sealed in an aluminum shell by using a colloidal particle to seal the opening to obtain a semi-finished capacitor; the semi-finished capacitor is cleaned and sleeved with a sleeve, and then is subjected to primary aging selection, appearance observation, and inspection, and then is obtained.

[0119] Comparative Example 7

[0120] The difference between the present comparative example and Example 1 is that the secondary aging selection conditions are consistent with the primary aging selection conditions.

[0121] Comparative Example 8

[0122] The difference between the present comparative example and Example 1 is that the electrolyte is bis-trifluoromethanesulfonylimide lithium and high-purity water.

[0123] Comparative Example 9

[0124] The difference between the present comparative example and Example 1 is that the organic solvent is ethylene carbonate, propylene carbonate, and methyl acetate.

[0125] Comparative Example 10

[0126] The difference between the present comparative example and Example 1 is that the volume ratio of the ethylene carbonate, propylene carbonate, and methyl acetate is 1:2:5.

[0127] Performance test

[0128] The capacitance, internal resistance, and 4s leakage current of the low-temperature-resistant detonator igniter special aluminum electrolytic capacitor are tested according to the method in GB / T 6346.1-2024 “Fixed Capacitors for Electronic Equipment Part 1: General Specification”.

[0129] High-temperature resistance test: The capacitor is stored at 85°C for 10,000 hours. After returning to room temperature for 1-2 hours, the capacitance of the aluminum electrolytic capacitor used for low-temperature detonator detonators is measured and the capacitance loss rate is calculated. The capacitance loss rate is (initial capacitance - capacitance after test) / initial capacitance × 100%.

[0130] Low-temperature resistance test: The capacitors were stored at -40°C for 10,000 hours. After returning to room temperature for 1-2 hours, the capacitance of the aluminum electrolytic capacitors used in this method for preparing low-temperature-resistant detonator detonators was measured, and the capacitance loss rate was calculated. The results are shown in Table 1.

[0131] Table 1 Measurement results

[0132]

[0133] According to statistics, the low-temperature resistant detonator detonator aluminum electrolytic capacitors prepared in Examples 1 to 3 of the present invention have excellent electrical properties, a wide operating temperature range, low internal resistance, and low leakage current. Comparative Example 1 does not add metal ions, Comparative Example 2 does not add hydrochloric acid, Comparative Example 3 has an excessively high average content of bleached sulfate softwood pulp fibers, Comparative Example 4 does not add a second cellulose fiber, Comparative Example 5 does not add 2,2,6,6-tetramethylpiperidinoxide, Comparative Example 6 does not undergo secondary aging screening, Comparative Example 7 has the same secondary aging screening conditions as the primary aging screening, Comparative Example 8 has water as the electrolyte, Comparative Example 9 does not contain γ-butyrolactone in the organic solvent, and Comparative Example 10 has an excessive amount of methyl acetate added. The prepared low-temperature resistant detonator detonator aluminum electrolytic capacitors each have defects. Therefore, the low-temperature resistant detonator detonator aluminum electrolytic capacitors prepared using the raw materials and methods described in this application have excellent electrical properties, a wide operating temperature range, low internal resistance, and low leakage current.

[0134] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a low-temperature resistant aluminum electrolytic capacitor for a detonator detonator, characterized in that: The following steps are involved: The positive electrode foil and the negative electrode foil are cut and riveted with the positive guide pin and the negative guide pin; the electrolytic paper is placed between the riveted positive electrode foil and the negative electrode foil and rolled to form a core package; the electrolyte is injected into the core package and the core package is sealed in an aluminum shell with colloid particles to obtain a semi-finished capacitor; the semi-finished capacitor is cleaned and then sleeved, and subjected to primary aging selection, secondary aging selection, appearance observation, and inspection in sequence to obtain the capacitor; The preparation method of the positive electrode foil is as follows: taking high-purity aluminum foil, performing pore-forming and pore-expanding treatment, and air-drying to obtain the positive electrode foil; The specific steps of pore formation are as follows: the impregnated aluminum foil is used as the anode and the graphite is used as the cathode, and the impregnated aluminum foil is placed in the pore formation solution at a temperature of 80-90°C and a current density of 0.1-0.2A / cm 2 The pore treatment was carried out for 2-3 minutes under the conditions of , and the aluminum foil was rinsed with deionized water and air-dried; The preparation method of electrolytic paper comprises: soaking bleached softwood sulfate pulp in deionized water, beating the pulp to a beating degree of 85-90°SR, and diluting the pulp with first deionized water to obtain a first liquid; dispersing modified cellulose fiber in a second deionized water, adding the dispersed fiber to the first liquid, homogenizing the fiber for 2-4 hours, making wet paper, pressing and drying the wet paper, and calendering the wet paper to obtain the electrolytic paper; The pore-forming solution is a mixed acid and metal ion aqueous solution; the content of metal ions in the pore-forming solution is 50-150 ppm; the metal ions include one or more of ferric ions, ferrous ions, cupric ions, and zinc ions; The average fiber length of bleached kraft softwood pulp is 2.8-3.2 mm, the average fiber roughness is 18-20 mg / 100 g, and the average fiber content is (2.8-3.0) × 10 6 roots / g, viscosity is 18-22CP; The cellulose fibers include first cellulose fibers and second cellulose fibers; the first cellulose fibers have a length of 0.1-1 nm and a diameter of 100-1000 nm; the second cellulose fibers have a length of 1-20 μm and a diameter of 20-80 nm; The preparation method of the modified cellulose fiber comprises: uniformly dispersing the cellulose fiber in a third deionized water, adding a modifier, adjusting the pH of the system to be stable between 10 and 10.5, reacting for 3 to 5 hours, washing the product with deionized water until it is neutral, and drying the product; the modifier is 2,2,6,6-tetramethylpiperidinyl oxide, sodium bromide, and sodium hypochlorite in a mass ratio of 1:(4-6):(290-310); The conditions for primary aging selection are: constant current and constant voltage are used, a constant current of 60-70μA is applied, and after the voltage reaches 440-460V, constant voltage aging is performed for 2-6 hours. After primary aging, the leakage current is tested, and if it is ≤40μA, it is qualified and enters the next step; The conditions for secondary aging selection are: using pulse and constant voltage methods, charging for 120s and discharging for 10s as one pulse, aging for 1-2h at a voltage of 440-460V, and testing the leakage current after secondary aging. If ≤40μA, it is qualified and proceeds to the next step.

2. A low-temperature resistant aluminum electrolytic capacitor specially used for detonator detonators prepared according to the preparation method of claim 1.

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