METHOD FOR MANUFACTURING A GRID ALLOY OF A LEAD-ACID BATTERY

Abstract

Method for producing a grid alloy for a lead-acid battery, wherein the components of the grid alloy of the lead-acid battery are the following: Tin 1.0 - 2.0 wt.%, Calcium 0.05 - 0.10 wt.%, Lanthanum 0.02 - 0.05 wt.%, Cerium 0.02 - 0.05 wt.%, Sodium 0.02 - 0.05 wt.% and Aluminium 0.01 - 0.04 wt.%, the remainder being lead; the manufacturing process comprises the following steps: (1) Producing an aluminium-lanthanum-cerium rare earth parent alloy by using a molten salt electrolysis process, wherein the process for producing the aluminium-lanthanum-cerium rare earth parent alloy by using the molten salt electrolysis process comprises the following steps: (a) Adding a mixture of lanthanum oxide, cerium oxide and aluminium oxide to an electrolyte system, wherein the mass ratio of the mixture to the electrolyte system is 1:50 - 1:10; (b) Carrying out a molten salt electrolysis eutectoid reaction to obtain the aluminium-lanthanum-cerium rare earth parent alloy, (2) Melting the aluminium-lanthanum-cerium rare earth parent alloy with sodium and partially lead and uniform stirring of the same to produce an intermediate alloy, the intermediate alloy being produced by using a vacuum melting process: • Place lead in a vacuum melting furnace, melt it, and then heat it to 950 - 1000 °C, • Addition of an aluminum-lanthanum-cerium rare earth parent alloy and sodium while stirring, • Stir for another 20-40 minutes and then • Cooling and pouring into an ingot at a temperature of 550 - 650 °C, (3) Melting the intermediate alloy with calcium, tin and remaining lead and stirring it uniformly to produce the lattice alloy of the lead-acid battery, wherein step (3) comprises: • Providing the lead in a lead smelting furnace, • Melting, and • subsequent heating to 620 - 670 °C, • Add the intermediate alloy while stirring and stirring for a further 10-15 minutes for even mixing; • Add calcium while stirring and continue stirring for another 10-15 minutes after the calcium has melted; • Add tin while stirring, stir for another 10-15 minutes after the tin has melted, and then • Cooling and pouring an ingot at a temperature of 550 - 600 ºC.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of lead-acid battery production and, for example, to a process for producing a grid alloy of a lead-acid battery. BACKGROUND

[0002] Lead-acid batteries are reversible direct current (DC) power supplies. A lead-acid battery can convert chemical energy into electrical energy and can also convert electrical energy into chemical energy. A lead-acid battery is mainly composed of an electrolyte, a battery can, and a plate assembly. The electrolyte in a lead-acid battery is sulfuric acid solution. The plate assembly is mainly composed of a positive plate, a negative plate, and a separator plate. The separator plate is primarily used to store the electrolyte and serves as a gas channel for oxygen recombination to prevent the active substances from falling off and causing a short circuit between the positive and negative electrodes.

[0003] In the manufacturing and processing of a storage battery, a grid serves as a carrier and conductor for the lead paste. The lead paste can only become a polar plate after it is filled and coated on the grid, cured, and dried. The polar plate is the core of the lead battery because the grid acts like a frame and directly affects the strength and service life of the entire polar plate. The grid of the lead battery has a shunt effect on the polar plate, so that the current is evenly distributed among the active substances and plays the role of a current collector, current convergence, and current transfer on a current conductor. Therefore, the grid of the lead battery is key to determining the battery's performance.

[0004] Patent publication number CN 1 01 656 312 B discloses an alloy material for a high-energy storage grid and a manufacturing method thereof. The alloy material is made from the following chemical compositions in weight percent: 0.06–0.14 percent Ca, 0.1–2.0 percent Sn, 0.01–0.06 percent Al, 0.01–0.1 percent Zn, 0.001–2.0 percent rare earth, and the balance Pb. The rare earth is one or two of Er and Yb, or a mixture of Ho, Er, Tm, and Yb.The manufacturing process includes the following steps: adding Ca, Al, and rare earth elements to a crucible furnace according to the compounding ratio; vacuuming, introducing nitrogen gas for protection, and melting the mixture at a temperature of 600-900°C; adding Pb, Sn, and Zn according to the compounding ratio, melting at a temperature of 550-650°C and mixing the mixture evenly; allowing to stand and then sampling (adjusting alloy compositions according to the sample compositions), then fishing out sediment, keeping the mixture at the above-mentioned temperature for 0.5-3 hours, and then cooling; regulating the cooling rate to 102-105 K / s.

[0005] Chinese Patent Publication No. CN 1 03 762 369 A discloses a rare earth lead alloy for a positive grid of a lead-acid storage battery. The rare earth lead alloy is characterized by being produced by melting the following component materials in weight percentage: 0.01 to 0.12 percent calcium, 1.2 to 2.0 percent tin, 0.02 to 0.05 percent aluminum, 0.01 to 0.12 percent lanthanum, 0.01 to 0.12 percent yttrium, 0.02 to 0.15 percent cerium, and the balance lead.

[0006] Patent Publication No. CN 1 02 329 982 B discloses a lead-antimony-rare earth anode grid alloy and a manufacturing method thereof. The lead-antimony-rare earth anode grid alloy consists of the following metal elements in weight percent: 0.5 to 1 percent antimony, 0.005 to 0.1 percent lanthanum, 0.005 to 0.1 percent samarium, and the remainder is lead. In the manufacturing process, lead-lanthanum and lead-samarium alloys were prepared as mother alloys; pure antimony was added to the molten lead solution and stirred until completely melted; and then lead-lanthanum and lead-samarium mother alloys were added, mixed, and melted to obtain the lead-antimony-rare earth anode grid alloy.

[0007] Rare earth metals have high melting points, typically around 1000°C or even higher. The existing process for producing a lead-rare earth alloy at such high temperatures results in high energy consumption and combustion losses. The recovery rate of rare earth metals is generally less than 80%, and the rare earth element content is difficult to control. Furthermore, rare earths can contain high levels of impurities. Direct production requires simple rare earth metal substances. However, rare earths exist naturally in the form of oxides. The production and purification of simple rare earth substances is energy-intensive and expensive. The produced alloy can also contain high levels of impurities.

[0008] CN 1 01 245 425 A relates to a lead-containing alloy, an application and a manufacturing process therefor.

[0009] CN 1 02 660 697A concerns a lead-acid battery grid alloy for electricity.

[0010] CN 1 556 252 A relates to the process for the direct production of an aluminium-cerium intermediate alloy using the molten salt electrolysis method. SUMMARY

[0011] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0012] The present application provides a method for producing a grid alloy of a lead-acid battery, which overcomes the problems of high energy consumption, large combustion loss, high impurity content, low utilization rate of rare earth metal, etc., in the related art in producing a rare earth alloy.

[0013] A method is provided for the production of a lead-acid battery grid alloy, wherein components of the lead-acid battery grid alloy are the following: Tin 1.0 - 2.0 wt%, calcium 0.05 - 0.10 wt%, lanthanum 0.02 - 0.05 wt%, cerium 0.02 - 0.05 wt%, sodium 0.02 - 0.05 wt% and aluminum 0.01 - 0.04 wt%, the remainder being lead; the manufacturing process comprising the following steps: (1) Producing an aluminum-lanthanum-cerium-rare earth mother alloy by using a molten salt electrolysis process, wherein the process for producing the aluminum-lanthanum-cerium-rare earth mother alloy using the molten salt electrolysis process comprises the following steps: (a) adding a mixture of lanthanum oxide, cerium oxide and aluminum oxide into an electrolyte system, wherein the mass ratio of the mixture to the electrolyte system is 1:50 - 1:10; (b) Carrying out a molten salt electrolysis eutectoid reaction to obtain the aluminum-lanthanum-cerium-rare earth mother alloy (2) Melting the aluminum-lanthanum-cerium-rare earth mother alloy with sodium and partially lead and stirring it uniformly to produce an intermediate alloy, wherein the intermediate alloy is produced by using a vacuum melting process: • Prepare lead in a vacuum melting furnace, melt and then heat to 950 - 1000 °C, • Addition of the aluminum-lanthanum-cerium-rare earth mother alloy and sodium while stirring, • Stir for another 20 - 40 minutes and then • Cooling and casting into an ingot at a temperature of 550 - 650 °C, (3) Melting the intermediate alloy with calcium, tin and the remaining lead and stirring it evenly to produce the grid alloy of the lead battery, wherein step (3) comprises: • Providing the lead in a lead melting furnace, • Melting, and • subsequent heating to 620 - 670 °C, • Add the intermediate alloy while stirring and stirring for another 10 - 15 minutes for even mixing; • Add calcium while stirring and stir for another 10 - 15 minutes after the calcium has melted;• Add tin while stirring, stir for another 10 - 15 minutes after the tin has melted, and then • Cooling and casting of an ingot at a temperature of 550 - 600 ºC.

[0014] Molten salt electrolysis is a metallurgical process in which electrical energy is used for heating and converted into chemical energy. Salts of certain metals are melted and used as electrolytes for electrolysis to extract and purify metals. When the molten electrolyte comes into contact with the metal, a certain potential difference, or electrode potential, is created between the two. Two electrodes are inserted into the same molten salt, and a direct current with an applied voltage is applied. When the voltage reaches a certain value, certain components in the molten salt are decomposed.

[0015] Optional components of the electrolyte system are: lanthanum fluoride 30-40 wt%, cerium fluoride 30-40 wt%, lithium fluoride 10-20 wt%, and barium fluoride 10-20 wt%. The fluoride electrolysis process can be applied to the production of rare earth metals with a low melting point.

[0016] Optionally, the amount of each component in the mixture of lanthanum oxide, cerium oxide, and aluminum oxide is 10-40 wt% lanthanum oxide, 10-40 wt% cerium oxide, and 30-80 wt% aluminum oxide. Since the ratio of a metal element to an oxygen element is different in each oxide, the mass ratio in each oxide mixture is different from that in the final lattice alloy.

[0017] Optionally, an electrolytic bath used for molten salt electrolysis is a graphite crucible with a graphite layer as an anode and a molybdenum rod as a cathode, and a molybdenum crucible is used as an alloy receiver; molten salt electrolysis is carried out at an anode current density of 1.0 - 1.5 A / cm 2 , a cathode current density of 15 - 20 A / cm 2 and an electrolysis temperature of 850–950 °C. Each parameter of molten salt electrolysis represents a range of conditions, with better results summarized based on a large number of experiments.

[0018] Optional components of the aluminum-lanthanum-cerium-rare earth mother alloy are: aluminum 10 - 50 wt%, lanthanum 25 - 50 wt% and cerium 25 - 50 wt%.

[0019] Optional components of the intermediate alloy are: aluminum 1 - 4 wt%, lanthanum 2 - 5 wt%, cerium 2 - 5 wt% and sodium 2 - 5 wt%, with the remainder being lead.

[0020] Optionally, the intermediate alloy is produced using a vacuum melting process. This process involves placing lead in a vacuum melting furnace, melting it, and then heating it to 950–1000°C. The aluminum-lanthanum-cerium-rare earth mother alloy and sodium are added while stirring. Stir for another 20–40 minutes, then cool and cast an ingot at a temperature of 550–650°C. The vacuum melting process is a special melting technology for melting metal and alloy under vacuum. One of the main disadvantages of atmospheric melting and casting is that alloy components (mainly some relatively active elements) are difficult to precisely control due to combustion loss.In contrast, vacuum melting is not contaminated by the surrounding atmosphere, and the metal liquid is separated from contact with oxygen and nitrogen in the atmosphere, allowing the content of active elements in the alloy to be tightly controlled. The alloy components are controlled within a narrow range, ensuring the performance, quality, and stability of the alloy.

[0021] Each parameter of the vacuum melting process is a range of conditions, with better results summarized based on a large number of experiments.

[0022] Optionally, the lead is electrolytic lead with a lead content ≥ 99.994%.

[0023] Compared with the process in which a simple substance of a rare earth element is prepared from an oxide and then a rare earth mother alloy is directly produced using the simple substance, the rare earth mother alloy produced using the molten salt electrolysis process in the present application has stable components, a lower impurity content, and a higher raw material utilization rate. Rare earth oxide is used directly as the raw material, making the raw material easier to obtain, and the rare earth element utilization rate reaches more than 90%. An intermediate alloy is prepared to produce the working alloy, so the components are more uniform and the process has high controllability.

[0024] Other aspects can be understood after reading and familiarizing with the detailed description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS The Fig. 1 is a flowchart of a method for manufacturing a lead-acid battery grid alloy according to a specific embodiment of the present application. The Fig. Figure 2 is a graph showing results of metallographic examination of a lattice alloy prepared in Comparative Example 1. The Fig. 3 is a graph showing results of metallographic examination of a lattice alloy prepared in Comparative Example 2. The Fig. Figure 4 is a diagram showing results of metallographic examination of a lattice alloy prepared in Example 7. The Fig. 5 is a graph showing results of metallographic examination of a grid prepared using the grid alloy prepared in Comparative Example 1. The Fig.6 is a graph showing results of metallographic examination of a grid prepared using the grid alloy prepared in Comparative Example 2. The Fig. Figure 7 is a graph showing results of metallographic examination of a grid prepared using the grid alloy prepared in Example 7. The Fig. Figure 8 is a graph showing cycle life test results of a battery in Example 14. DETAILED DESCRIPTION

[0025] The technical solutions of the present application are further described below through specific examples. Those skilled in the art should understand that the examples described herein are used merely to better understand the present application and should not be construed as specific limitations of the present application.

[0026] The Fig. 1 is a flow diagram of a method for producing a lead-acid battery grid alloy according to a specific embodiment of the present application. As shown in Fig. As shown in Figure 1, an aluminum-lanthanum-cerium-rare earth mother alloy was prepared, then an intermediate alloy was prepared using the aluminum-lanthanum-cerium-rare earth mother alloy, sodium, and partial lead, and finally the lead battery grid alloy was prepared using the intermediate alloy, calcium, tin, and residual lead. Example 1

[0027] An aluminum-lanthanum-cerium-rare earth mother alloy was prepared using a molten salt electrolysis process.

[0028] The mass ratio of components in the electrolyte system was LaF3:CeF3:LiF:BaF2 = 40:40:10:10. The mass ratio of added raw materials was La2O3:CeO2:Al2O3 = 25:25:50. Molten salt electrolysis was carried out at a current of 2800 A and an anode current density of 1.0–1.2 A / cm 2 , a cathode current density of 15 - 18 A / cm 2 and an electrolysis temperature of 880-910 °C. The electrolyte mass in the electrolytic furnace was 100 kg. 5 kg of raw materials were added, and 2.6 kg of alloy was produced. The alloy contained 39.2% lanthanum and 37.1% cerium. The metal lanthanum recovery rate was 95.9%, and the metal cerium recovery rate was 95.1%. The components of the produced aluminum-lanthanum-cerium-rare earth mother alloy are shown in Table 1, where Fe, Si, C, Cu, Ag, and Sb are impurities, which is the same as in the examples described below. Table 1 Aluminium-lanthanum-cerium-rare earth mother alloy component - analytical results (in wt%) La Ce Al Fe Si C Cu Ag Sb 39,2 37,1 22,3 0,08 0,02 0,01 0,002 0,0004 0,001 Example 2

[0029] An aluminum-lanthanum-cerium-rare earth mother alloy was prepared using the molten salt electrolysis process.

[0030] The mass ratio of components in an electrolyte system was LaF3:CeF3:LiF:BaF2 = 30:30:20:20. The mass ratio of added raw materials was La2O3:CeO2:Al2O3 = 40:30:30. The molten salt electrolysis was carried out at a current of 2700 A and an anode current density of 1.2–1.4 A / cm 2 , a cathode current density of 18 - 20 A / cm 2and an electrolysis temperature of 920–950 °C. The electrolyte mass in the electrolytic furnace was 250 kg. 5 kg of raw materials were added, and 3.2 kg of alloy was produced. The alloy contained 49.8% lanthanum and 36.2% cerium. The metal recovery rate of lanthanum was 92.2%, and the metal recovery rate of cerium was 93.6%. The components of the produced aluminum-lanthanum-cerium-rare earth mother alloy are shown in Table 2. Table 2 Aluminium-lanthanum-cerium-rare earth mother alloy component - analytical results in wt.%) La Ce Al Fe Si C Cu Ag Sb 49,8 36,2 12,5 0,06 0,02 0,02 0,001 0,0003 0,001 Example 3

[0031] An aluminum-lanthanum-cerium-rare earth mother alloy was prepared using the molten salt electrolysis process.

[0032] The mass ratio of components in an electrolyte system was LaF3:CeF3:LiF:BaF2 = 40:40:10:10. The mass ratio of added raw materials was La2O3:CeO2:Al2O3 = 15:15:70. The molten salt electrolysis was carried out at a current of 2600 A and an anode current density of 1.3–1.5 A / cm 2 , a cathode current density of 17 - 20 A / cm 2 and an electrolysis temperature of 850-880 °C. The electrolyte mass in the electrolytic furnace was 50 kg. 5 kg of raw materials were added, and 2.1 kg of alloy was produced. The alloy contained 28.4% lanthanum and 27.3% cerium. The metal recovery rate of lanthanum was 90.1%, and the metal recovery rate of cerium was 92.5%. The components of the produced aluminum-lanthanum-cerium-rare earth mother alloy are shown in Table 3. Table 3 Aluminium-lanthanum-cerium-rare earth mother alloy component - analytical results (in wt%) La Ce Al Fe Si C Cu Ag Sb 28,1 27,3 43,1 0,07 0,01 0,02 0,002 0,0005 0,001 Example 4

[0033] An intermediate alloy was prepared using the aluminum-lanthanum-cerium-rare earth mother alloy prepared in Example 1.

[0034] 25 kg of pure lead was placed in a vacuum melting furnace. The lead was melted and then heated to 980 °C. 2.5 kg of the rare earth mother alloy prepared in Example 1 and 1.0 kg of sodium metal were added with stirring, stirred for another 30 minutes, and then cooled. After the sediment was removed, ingot casting was performed at 600 °C to obtain 28.2 kg of alloy. The alloy contained 3.38% lanthanum, 3.29% cerium, 1.76% aluminum, and 3.44% sodium. The components of the prepared intermediate alloy are shown in Table 4. Table 4 Intermediate alloy component - analysis results (in wt%) La Ce Al N / a Fe Si C 3,38 3,29 1,76 3,44 0,008 0,002 0,001 Cu Ag Bi Zn Sb Pb - 0,0002 0,0003 0,003 0,0003 0,0008 rest - Example 5

[0035] An intermediate alloy was prepared using the aluminum-lanthanum-cerium-rare earth mother alloy prepared in Example 2.

[0036] 25 kg of pure lead was placed in a vacuum melting furnace. The lead was melted and then heated to 1000 °C. 3.0 kg of the rare earth mother alloy prepared in Example 2 and 1.5 kg of metallic sodium were added with stirring, stirred for another 30 minutes, and then cooled. After the sediment was removed, ingot casting was performed at 600 °C to obtain 29.2 kg of alloy. The alloy contained 4.96% lanthanum, 3.68% cerium, 1.23% aluminum, and 4.88% sodium. The components of the prepared intermediate alloy are shown in Table 5. Table 5 Intermediate alloy component - analysis results (in wt%) La Ce Al N / a Fe Si C 4,96 3,68 1,23 4,88 0,006 0,002 0,002 Cu Ag Bi Zn Sb Pb - 0,0003 0,0004 0,002 0,0003 0,0007 rest - Example 6

[0037] An intermediate alloy was prepared using the aluminum-lanthanum-cerium-rare earth mother alloy prepared in Example 3.

[0038] 20 kg of pure lead was placed in a vacuum melting furnace. The lead was melted and then heated to 950 °C. 2.0 kg of the rare earth mother alloy prepared in Example 3 and 0.5 kg of sodium metal were added with stirring, stirred for another 30 minutes, and then cooled. After the sediment was removed, ingot casting was performed at 600 °C to obtain 22.3 kg of alloy. In the alloy, the lanthanum content was 2.42%, the cerium content was 2.38%, the aluminum content was 3.66%, and the sodium content was 2.12%. The components of the prepared intermediate alloy are shown in Table 6. Table 6 Intermediate alloy component - analysis results (in wt%) La Ce Al N / a Fe Si C 2,42 2,38 3,66 2,12 0,007 0,001 0,002 Cu Ag Bi Zn Sb Pb 0,0004 0,0005 0,002 0,0004 0,0007 rest Example 7

[0039] A final product (working alloy) was prepared using the intermediate alloy prepared in Example 4.

[0040] 1000 kg of lead was placed in a lead melting furnace, melted by heating, and then heated to 630–660 °C. 10 kg of the intermediate alloy prepared in Example 4 was added with stirring and stirred for another 15 minutes for uniform mixing. 0.6 kg of calcium was added with stirring. Stirring continued for 15 minutes after the calcium melted. 20 kg of tin was added with stirring. Stirring continued for 15 minutes after the tin melted. The temperature was reduced. After the sediment was fished out, ingot casting was performed at 550 °C to obtain a working alloy. The components of the prepared working alloy are shown in Table 7. Table 7 Working alloy component - analysis results (in wt%) Sn Ca La Ce Al N / a Bi Cu 1,92 0,055 0,032 0,032 0,015 0,033 0,005 0,001 Ace Ag Zn Ni Sb Fe CD Pb 0,001 0,005 0,0005 0,0002 0,001 0,0005 0,0002 rest Example 8

[0041] A final product (working alloy) was prepared using the intermediate alloy prepared in Example 5.

[0042] 1000 kg of lead was placed in a lead melting furnace, melted by heating, and then heated to 650-670 °C. 10 kg of the intermediate alloy prepared in Example 5 was added with stirring and stirred for another 15 minutes for uniform mixing. 0.8 kg of calcium was added with stirring. Stirring continued for 15 minutes after the calcium melted. 16 kg of tin was added with stirring. Stirring continued for 15 minutes after the tin melted. The temperature was reduced. After the sediment was fished out, ingot casting was performed at 550 °C to obtain a working alloy. The components of the prepared working alloy are shown in Table 8. Table 8 Working alloy component - analysis results (in wt%) Sn Ca La Ce Al N / a Bi Cu 1,53 0,073 0,048 0,036 0,011 0,046 0,005 0,001 Ace Ag Zn Ni Sb Fe CD Pb 0,001 0,005 0,0005 0,0002 0,001 0,0005 0,0002 rest Example 9

[0043] A final product (working alloy) was produced using the intermediate alloy prepared in Example 6.

[0044] 1000 kg of lead was placed in a lead melting furnace, melted by heating, and then heated to 620-650 °C. 10 kg of the intermediate alloy prepared in Example 6 was added with stirring and stirred for another 15 minutes for uniform mixing. 1.0 kg of calcium was added with stirring. Stirring continued for 15 minutes after the calcium melted. 12 kg of tin was added with stirring. Stirring continued for 15 minutes after the tin melted. The temperature was reduced. After the sediment was fished out, ingot casting was performed at a temperature of 550 °C to obtain a working alloy. The components of the prepared working alloy are shown in Table 9. Table 9 Working alloy component - analysis results (in wt%) Sn Ca La Ce Al N / a Bi Cu 1,13 0,092 0,022 0,021 0,036 0,021 0,005 0,001 Ace Ag Zn Ni Sb Fe CD Pb 0,001 0,005 0,0005 0,0002 0,001 0,0005 0,0002 rest Comparative Example 1Process for the production of a common lead-calcium-tin alloy

[0045] A certain amount of pure lead was placed in a lead melting furnace. The lead was melted and then heated to 580–600°C. After the sediment was removed, the molten lead was stirred at high speed. A calcium-aluminum mother alloy (Ca / Al: 75:25 by weight), corresponding to 0.13% of the pure lead, was added and stirred for another 15 minutes. Pure tin, corresponding to 1.5% of the pure lead, was added and stirred continuously for 15 minutes. Then, the temperature was reduced. After the sediment was removed, ingot casting was carried out at a temperature of 550°C to obtain a lead-calcium-tin alloy. The alloy components are shown in Table 10. Table 10 Common lead-calcium-tin alloy components - analysis results (in wt%) Sn Ca Al Bi Cu Ace Ag Zn Ni Sb Fe CD Pb 1,216 0,074 0,022 0,003 0,001 0,001 0,005 0,0005 0,0002 0,001 0,0005 0,0002 rest Comparison example 2

[0046] Process for the production of a lead-rare earth alloy by direct addition of rare earth elements

[0047] A certain amount of pure lead was placed in a lead melting furnace. The lead was melted and then heated to 880–900°C. After the sediment was fished out, the molten lead was stirred at high speed. Pure lanthanum, corresponding to 0.04% of pure lead by weight, and pure cerium, corresponding to 0.04% of pure lead by weight, were added and stirred at high speed for 10 minutes. Stirring continued, and the temperature was reduced to 560–580°C. Metallic sodium, corresponding to 0.06% of pure lead by weight, was added and stirred at high speed for 10 minutes. A calcium-aluminum mother alloy (Ca / Al: 75:25 by weight), corresponding to 0.13% of pure lead by weight, was added and stirred for another 15 minutes. Pure tin, whose weight corresponded to 1.5% of pure lead, was added and stirred for another 15 minutes.The temperature was then reduced. After the sediment was removed, ingot casting was performed at a temperature of 550 °C to obtain a lead-rare earth alloy. The alloy components are shown in Table 11. Table 11 Component - Analysis results of the lead-rare earth alloy produced by direct addition of rare earth elements (in wt%) Sn Ca La Ce Al N / a Bi Cu 1,223 0,076 0,026 0,027 0,025 0,032 0,004 0,001 Ace Ag Zn Ni Sb Fe CD Pb 0,001 0,005 0,0005 0,0002 0,001 0,0005 0,0002 rest Example 10Metallographic examination:

[0048] The lead alloy was prepared into a sample with a diameter of 10 mm and a length of 20 mm. The sample was ground using a metallographic grinder. During the grinding process, the rotation speed of the grinding wheel was regulated to 800 rpm, and water was used as a lubricant and cooling fluid. 300# and 600# metallographic abrasive papers were used for rough grinding, followed by 1500# and 2000# abrasive papers for fine grinding. The ground sample was polished using a polymer synthetic cloth. After polishing, the sample was washed with water for a second cleaning, corroded using a mixed solution of analytically pure acetic acid and hydrogen peroxide (the volume ratio was 1:3), soaked and washed in absolute ethyl alcohol, and blown dry using an electric blower.The texture structure of the surface of the alloy was examined under a metallographic microscope.

[0049] The alloys produced in Comparative Example 1, Comparative Example 2 and Example 7 were determined. The test results are shown in the Fig. 2, Fig. 3 and Fig. 4. It can be seen that the common lead-calcium alloy (prepared in Comparative Example 1) had coarse crystal grains of more than 200 μm and clear segregation; the common lead-rare earth alloy (prepared in Comparative Example 2) had slightly fine crystal grains but irregular crystal boundaries, and also had black-spotted or butterfly-shaped impurities or segregation points; the lead-rare earth alloy prepared in Example 7 had finer crystal grains of about 10 μm, regular grain boundaries, and less segregation. Example 11

[0050] The lattice alloys prepared in Comparative Example 1, Comparative Example 2, and Example 7 were each cast into lattices. The metallographic structures of these lattices were verified. The verification results are shown in the Fig. 5, Fig. 6 and Fig.7. It can be seen from the metallography of the grids that the grid cast by the common lead-calcium-tin alloy (prepared in Comparative Example 1) had large crystal grains, irregular crystal boundaries, and multiple intermetallic compounds were precipitated; the grid cast by the common lead-rare earth alloy (prepared in Comparative Example 2) had fine crystal grains, but very uneven sizes and irregular crystal boundaries, and a certain amount of intermetallic compounds were precipitated; the lead-rare earth alloy prepared in Example 7 had fine and evenly distributed crystal grains, regular grain boundaries, and fewer impurities. Example 12

[0051] The alloys prepared in Example 7, Comparative Example 1, and Comparative Example 2 were each cast into grids. A constant current corrosion test was conducted by introducing a 50 mA current into a 1.28 g / mL sulfuric acid solution. In the test procedure, the corrosion area was 5 cm 2 and the corrosion duration was 20 days. The weight loss data of the sample after corrosion were examined to calculate the average corrosion weight loss per day to measure the corrosion resistance of the alloy sample. The lower the average corrosion weight loss per day, the stronger the corrosion resistance of the alloy. The results are shown in Table 12. It can be seen that the grid alloy produced by the production method of the present application has better corrosion resistance. Table 12 Corrosion resistance - Test results alloy Before corrosion / g After corrosion / g Weight loss / mg Corrosion rate mg / d Comparison example 1 48,6565 48,0138 642,70 30,60 Comparison example 2 48,0112 47,4646 546,60 26,03 Example 7 47,9411 47,6292 311,90 14,85 Example 13

[0052] The alloys prepared in Example 7, Comparative Example 1, and Comparative Example 2 were each cast into grids. The grids were each formed into a polar plate, and a battery was assembled for cycling. A charge / discharge cycle with 100% depth of discharge (100% DoD) was performed. The battery was disassembled after 200 cycles were completed. The size change of the grid was measured to evaluate the creep resistance of the alloy. The smaller the size change, the greater the creep resistance. The results are shown in Table 13. It can be seen that the grid alloy prepared by the manufacturing method of the present application has better creep resistance. Table 13 Creep resistance - verification results alloy Initial height / mm Height after cycles / mm Height increase / mm Altitude change rate Comparison example 1 136,12 137,58 1,46 1,07% Comparison example 2 136,15 137,46 1,31 0,96% Example 7 136,13 136,76 0,63 0,46% Example 14

[0053] The alloys prepared in Example 7, Comparative Example 1, and Comparative Example 2 were each cast into grids. The grids were each formed into a polar plate, and a battery was assembled to conduct a cycle test. A charge / discharge cycle with 100% DoD was performed. The test was terminated when the discharge capacity of the battery was lower than 96 minutes for three consecutive times, and the battery was deemed to be useless. The number of completed cycles before the battery was deemed to be useless was counted and recorded as the battery life. The results are shown in the Fig.8. The life cycle of the battery manufactured by the grid alloy (manufactured in Example 7) by the manufacturing method of the present application reached 491 times, the life cycle of the battery manufactured by the common alloy manufactured in Comparative Example 1 was 292 times, and the life cycle of the battery manufactured by the common lead-rare earth alloy manufactured in Comparative Example 2 was 368 times, which indicates that the life cycle of the battery can be significantly extended by the grid alloy manufactured by the manufacturing method of the present application.

Claims

[1] A method for producing a lead-acid battery grid alloy, wherein the components of the lead-acid battery grid alloy are the following: Tin 1.0 - 2.0 wt%, calcium 0.05 - 0.10 wt%, lanthanum 0.02 - 0.05 wt%, cerium 0.02 - 0.05 wt%, sodium 0.02 - 0.05 wt% and aluminum 0.01 - 0.04 wt%, the remainder being lead; the manufacturing process comprising the following steps: (1) Producing an aluminum-lanthanum-cerium-rare earth mother alloy by using a molten salt electrolysis process, wherein the process for producing the aluminum-lanthanum-cerium-rare earth mother alloy by using the molten salt electrolysis process comprises the following steps: (a) adding a mixture of lanthanum oxide, cerium oxide and aluminum oxide to an electrolyte system, wherein the mass ratio of the mixture to the electrolyte system is 1:50 - 1:10; (b) Carrying out a molten salt electrolysis - eutectoid reaction to obtain the aluminium-lanthanum-cerium-rare earth mother alloy, (2) Melting the aluminum-lanthanum-cerium-rare earth mother alloy with sodium and partially lead and stirring it uniformly to produce an intermediate alloy, wherein the intermediate alloy is produced by using a vacuum melting process: • Providing lead in a vacuum melting furnace, melting, and then heating to 950 - 1000 ºC, • Addition of an aluminum-lanthanum-cerium-rare earth mother alloy and sodium while stirring, • Stir for another 20 - 40 minutes and then • Cooling and casting into an ingot at a temperature of 550 - 650 ºC, (3) Melting the intermediate alloy with calcium, tin and remaining lead and stirring it evenly to produce the grid alloy of the lead battery, wherein step (3) comprises: • Providing the lead in a lead melting furnace, • Melting, and • subsequent heating to 620 - 670 ºC, • Add the intermediate alloy while stirring and stirring for another 10 - 15 minutes for even mixing; • Add calcium while stirring and stir for another 10 - 15 minutes after the calcium has melted; • Add tin while stirring, stir for another 10 - 15 minutes after the tin has melted, and then • Cooling and casting of an ingot at a temperature of 550 - 600 ºC. [2] A manufacturing method according to claim 1, wherein components of the electrolyte system are: lanthanum fluoride 30-40 wt%, cerium fluoride 30-40 wt%, lithium fluoride 10-20 wt% and barium fluoride 10-20 wt%. [3] The manufacturing method according to claim 1 or 2, wherein the amount of each component in the mixture of lanthanum oxide, cerium oxide and alumina is: lanthanum oxide 10 - 40 wt%, cerium oxide 10 - 40 wt% and alumina 30 - 80 wt%. [4] A manufacturing method according to any one of claims 1 to 3, wherein an electrolytic bath used for the molten salt electrolysis is a graphite crucible having a graphite layer as an anode, a molybdenum rod as a cathode, and a molybdenum crucible as an alloy receiver; the molten salt electrolysis is carried out at an anode current density of 1.0 - 1.5 A / cm 2 , a cathode current density of 15 - 20 A / cm 2 and an electrolysis temperature of 850 - 950 ºC. [5] A manufacturing method according to any one of claims 1 to 4, wherein components of the aluminum-lanthanum-cerium-rare earth mother alloy are: aluminum 10-50 wt%, lanthanum 25-50 wt% and cerium 25-50 wt%. [6] A manufacturing method according to any one of claims 1 to 5, wherein components of the intermediate alloy are: aluminum 1-4 wt%, lanthanum 2-5 wt%, cerium 2-5 wt% and sodium 2-5 wt%, the remainder being lead. [7] A manufacturing method according to any one of claims 1 to 6, wherein the lead is electrolytic lead having a lead content of ≥ 99.994%.

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