A lead calcium alloy flux

Abstract

The present application relates to a kind of lead calcium alloy flux, for lead alloy plate lug casting welding process.It includes the following mass percentage of raw materials: glycolic acid: 35-40%;Ethanol: 8-12%;Surfactant: 1-2%;Hydrogenated rosin: 0.5-1%;Deionized water: 45-50%.Compared with prior art, the beneficial effects of the present application are: the acidity of the flux of the present application is moderate, can react with PbO while not corroding lead calcium alloy to cause plate lug thinning, after using the flux of the present application instead of phosphorous acid flux, the battery failure caused by plate lug break in annual external battery failure analysis is reduced from 10% to 2%;It has the advantages of low toxicity, will not cause corrosion to related metal equipment;Casting welding area is controllable;It has the advantages of low toxicity, will not cause corrosion to related metal equipment;Casting welding area is controllable;Casting welding temperature is low;Plate lug surface is clean, casting welding effect is good, without air hole, without black smoke and the like.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a flux used in the casting and welding process of lead alloy plates. Background Technology

[0002] Currently, in battery production, multiple plates need to be welded onto the busbar. Before the casting and welding process, a layer of flux is brushed onto the lead alloy plates to dissolve or remove the oxide film on the surface of the plates, thus improving the quality of the casting and welding. At present, most factories use two types of flux:

[0003] The shortcomings of oil-based flux are: 1. The spreading speed of oil-based flux on lead alloy plates is too slow, and it cannot cover the welding area within the production cycle time, resulting in incomplete welding, increased battery resistance, and affected battery performance. 2. Oil-based flux reacts slowly with oxides on lead alloy plates, and oxide residues remain suspended on the alloy surface, making them difficult to remove.

[0004] Water-based flux: The main component is phosphorous acid. The main active ingredient in phosphorous acid flux is inorganic acid, which can quickly remove the PbO oxide film on the surface of the plate ear. However, it also has the following disadvantages: 1. Phosphorous acid has good wettability on the plate ear surface, spreads quickly, and easily spreads to non-soldering areas. Figure 1 1. (Above the positive crescent) Phosphorous acid causes corrosion and thinning of the alloy in the non-welded area, thus affecting the subsequent discharge performance and lifespan of the battery. 2. During normal use, phosphorous acid can cause irreversible corrosion to related metal equipment, reducing its lifespan and increasing production costs. 3. Phosphorous acid itself is irritating to the respiratory tract and can cause burns and permanent damage to the eyes upon contact. It is also harmful to the environment and water systems. 4. Phosphorous acid has a decomposition temperature of 180℃ and a boiling point of 200℃. During the casting and welding process, the pouring temperature reaches as high as 470-490℃, causing environmental pollution after the decomposition and volatilization of phosphorous acid. After casting and welding, most of the unreacted phosphorous acid remains on the surface of the lugs, causing an increase in resistance at the connection between the cast / welded part and the lugs, affecting the battery discharge current. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings of the prior art and provide a lead-calcium alloy flux that has low toxicity, does not corrode related metal equipment, has controllable casting and welding area, low casting and welding temperature (lead liquid temperature), clean plate and ear surface, good casting and welding effect, no porosity, and no black smoke.

[0006] The lead-calcium alloy flux of the present invention comprises the following raw materials in weight percentages:

[0007] Glycolic acid: 35-40%; Ethanol: 8-12%; Surfactant: 1-2%; Hydrogenated rosin: 0.5-1%;

[0008] Deionized water: 45-50%.

[0009] The optimal formulation of this invention is as follows: glycolic acid: 38%; ethanol: 10%; surfactant: 2%; hydrogenated rosin: 1%; deionized water: 49%.

[0010] The surfactant of the present invention is trimethylbutenediol, dibromobutenediol or 1-ethoxyperfluorobutane.

[0011] The surfactant used in this invention is preferably 1-ethoxyperfluorobutane.

[0012] The molecular formula of the hydrogenated rosin is:

[0013]

[0014] The manufacturing method of the lead-calcium alloy flux of the present invention is as follows: Ethanol is added to a stainless steel reactor with stirring at room temperature. Stirring is started and the temperature is controlled at 20-30°C. Rosin is added and stirred for 0.5-1 hour until the hydrogenated rosin is completely dissolved. Then, surfactant, glycolic acid and deionized water are added in sequence. After the addition is completed, stirring is continued for 0.5-1 hour.

[0015] In the above technical solution, glycolic acid reacts with the PbO oxide film to generate organic salts, which are then dissolved in the flux and removed, effectively pickling the surface of the plate. The addition of 1-ethoxyperfluorobutane adjusts the flux spreading speed on the lead-calcium alloy surface, ensuring it spreads evenly across the welding area within the production cycle, reducing surface tension and allowing for better flux spreading on the alloy surface. Hydrogenated rosin decomposes at high temperatures to generate organic acids, accelerating the dissolution of the PbO oxide film. Simultaneously, the reaction products float on the flux surface, facilitating removal.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] 1. The flux of the present invention has moderate acidity, which can react with PbO without corroding the lead-calcium alloy and causing the plate lugs to thin. After using the flux of the present invention to replace the phosphorous acid flux, the proportion of battery failures caused by plate lug breakage in the annual external battery failure analysis decreased from 10% to 2%.

[0018] 2. During normal use, the flux of this invention will not cause corrosion to the relevant metal equipment;

[0019] 3. The flux of this invention is odorless and has low toxicity.

[0020] 4. During casting and welding, organic substances such as glycolic acid are directly vaporized, which does not affect the battery discharge current.

[0021] 5. Before welding, the plate ear undergoes flux application (2 seconds) (before casting and welding, relevant equipment will first apply flux to the designated position on the plate ear surface, this process lasts for 2 seconds) and surface cleaning (2 seconds). The welding time is controlled between 2 and 4 seconds. According to the production process requirements, after applying flux for 2 seconds, the flux spreading distance is best at 3 mm. The flux of this invention can complete the neutralization reaction with the oxide film on the lead alloy surface within 2 seconds after application, and the flux spreading distance after 2 seconds is about 3 mm, which is just enough to cover the welding area.

[0022] 6. The flux of this invention has a low boiling point and vaporizes rapidly during welding, preventing the formation of pores inside the weldment and ensuring welding quality. Simultaneously, the casting temperature is relatively low, around 410 degrees Celsius, saving energy in the welding process. Differences in flux composition lead to differences in casting temperature requirements. Different compositions result in different polarities and intermolecular forces, leading to different boiling points. The flux of this invention has low polarity and a low boiling point, ensuring complete vaporization at a lower casting temperature. No pores remain in the cast weld manifold. Attached Figure Description

[0023] Figure 1 This is a diagram showing the spreading state of phosphorous acid on the surface of the plate ear in existing phosphorous acid flux.

[0024] In the diagram, busbar 1; lug 2; positive meniscus 3 is the non-welded area; negative meniscus 4 is the welded area.

[0025] Phosphorous acid has good wettability on the surface of the lug 2 and spreads quickly. It can easily spread to the position above the positive meniscus 3 in the non-welded area, causing alloy corrosion and thinning in the non-welded area, which in turn affects the discharge performance and service life of the subsequent battery. Detailed Implementation

[0026] Example 1

[0027] Glycolic acid: 38%; Ethanol: 10%; 1-Ethoxyperfluorobutane: 2%; Hydrogenated rosin: 1%;

[0028] Deionized water: 49%.

[0029] The manufacturing method of the lead-calcium alloy flux of the present invention is as follows: ethanol is added to a stainless steel reactor with stirring at room temperature, stirring is turned on and the temperature is controlled to 25°C, solid rosin is added, and stirring is carried out for 0.5 h until the rosin is completely dissolved. Then, 1-ethoxyperfluorobutane, glycolic acid and deionized water are added in sequence. After the addition is completed, stirring is continued for 0.5 h to obtain the lead-calcium alloy flux of the present invention.

[0030] Example 2

[0031] Glycolic acid: 40%; Ethanol: 9%; 1-Ethoxyperfluorobutane: 1.5%; Hydrogenated rosin: 1%;

[0032] Deionized water: 48.5%.

[0033] The manufacturing method of the lead-calcium alloy flux of the present invention is as follows: ethanol is added to a stainless steel reaction vessel with stirring at room temperature, stirring is turned on and the temperature is controlled to 28°C, solid rosin is added, and stirring is carried out for 1 hour until the rosin is completely dissolved. Then, 1-ethoxyperfluorobutane, glycolic acid and deionized water are added in sequence. After the addition is completed, stirring is continued for 0.5 hours to obtain the lead-calcium alloy flux of the present invention.

[0034] Example 3

[0035] Glycolic acid: 37%; Ethanol: 11%; 1-Ethoxyperfluorobutane: 2%; Hydrogenated rosin: 0.8%; Deionized water: 49.2%.

[0036] The manufacturing method is as follows: Ethanol is added to a stainless steel reactor with stirring at room temperature. When stirring is turned on and the temperature is controlled to 20°C, solid rosin is added. After stirring for 0.5 hours until the hydrogenated rosin is completely dissolved, 1-ethoxyperfluorobutane, glycolic acid and deionized water are added in sequence. After the feeding is completed, stirring is continued for 0.5 hours to obtain the lead-calcium alloy flux of the present invention.

[0037] Example 4

[0038] Glycolic acid: 37%; Ethanol: 11%; Dibromobutenediol: 2%; Hydrogenated rosin: 0.8%; Deionized water: 49.2%.

[0039] The manufacturing method is the same as in Example 1.

[0040] Example 5

[0041] Glycolic acid: 37%; Ethanol: 11%; Trimethylbutenediol: 2%; Hydrogenated rosin: 0.8%; Deionized water: 49.2%.

[0042] The manufacturing method is the same as in Example 1.

[0043] Comparative Example 1

[0044] Organic acid activator (succinic acid): 4%; Surfactant (triethanolamine): 3%; Film-forming agent 1% (polyacrylamide); Corrosion inhibitor: 0.07%; Carrier solvent balance (ethanol).

[0045] Add the raw materials to the reactor at room temperature, and continue stirring for 1-2 hours after the materials have been added.

[0046] Comparative Example 2

[0047] Glycolic acid: 70%; Ethanol: 10%;

[0048] Dibromobutenediol: 2%; Deionized water: 18%.

[0049] Add the raw materials to the reactor at room temperature, and continue stirring for 1-2 hours after the materials have been added.

[0050] Comparative Example 3

[0051] Phosphorous acid 35%, deionized water 55%, triethyl phosphate 10%.

[0052] Add the raw materials to the reactor at room temperature, and continue stirring for 1-2 hours after the materials have been added.

[0053] Verification test data: (L2400 small-sized flooded battery, structure LESN5+\KESN6-, 6+ / 5-, single-factor test, comparing the effects of two fluxes on battery discharge performance), Table 1 shows the verification test data of the embodiment of the present invention; Table 2 shows the verification test data of the comparative example.

[0054] Table 1

[0055]

[0056] Table 2

[0057]

[0058] The above termination voltage is for 880A high-current discharge. The CCA and termination voltage of batteries in Examples 1, 2, and 3 are significantly better than those in other examples and comparative examples.

[0059] Table 3

[0060]

[0061] In the above embodiments and comparative examples, the 2S spreading distance (on the lead-calcium alloy surface) of Example 1 is 3mm, which meets the production cycle requirements.

[0062] Table 4 shows a comparison of the comparative examples and the fault data of the present invention.

[0063] Table 4

[0064]

Claims

1. A lead-calcium alloy flux, characterized in that: Including the following percentages by weight of raw materials: Glycolic acid: 35-40%; Ethanol: 8-12%; Surfactant: 1-2%; Hydrogenated rosin: 0.5-1%; Deionized water: 45-50%; The surfactant is trimethylbutenediol, dibromobutenediol, or 1-ethoxyperfluorobutane.

2. The lead-calcium alloy flux according to claim 1, characterized in that: The optimal ratio is: glycolic acid: 38%; ethanol: 10%; surfactant: 2%; hydrogenated rosin: 1%; deionized water: 49%.

3. A method for manufacturing the lead-calcium alloy flux according to claim 1, characterized in that: Add ethanol to a stainless steel reactor with a stirrer at room temperature. Turn on the stirrer and control the temperature to 20-30℃. Add hydrogenated rosin and stir for 0.5-1 hour until the hydrogenated rosin is completely dissolved. Then add the surfactant, glycolic acid and deionized water in sequence. After the addition is complete, continue stirring for 0.5-1 hour.

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