Positive grid and preparation method therefor, positive electrode plate and lead-acid battery

Abstract

The present invention relates to the technical field of lead-acid batteries, and provides a positive grid and a preparation method therefor, a positive electrode plate and a lead-acid battery. The positive grid is prepared from the following components: Ca; Al; Sn; Re; Mg; and lead: the balance. The preparation method for a positive grid comprises: S1, lead melting; S2, a first instance of slagging; S3, a second instance of slagging; S4, the addition of metal components; S5, cooling; and S6, sampling and testing. Also provided are a positive electrode plate and a lead-acid battery.

Description

Positive electrode grid, preparation method, positive electrode plate and lead-acid battery Technical Field

[0001] This application relates to the field of lead-acid battery technology, specifically to positive electrode grids, preparation methods, positive electrode plates, and lead-acid batteries. Background Technology

[0002] The grid is the most important inactive material in lead-acid batteries. Since the invention of lead-acid batteries, Pb-Sb alloy has been the primary material used for grids. With the advent of maintenance-free lead-acid batteries, Pb-Sb alloy can no longer meet the performance requirements of maintenance-free batteries and has been gradually replaced by other alloys. Studies have found that Pb-Ca alloy has excellent maintenance-free performance, but its intergranular corrosion is severe, and the calcium content is difficult to control. In particular, the high-resistivity passivation film formed on the surface of the battery grid severely hinders the charging and discharging process, exacerbating early capacity loss (PCL) and thus greatly shortening the cycle life of lead-acid batteries.

[0003] Cycle life is an important indicator of lead-acid batteries, affecting their application in many fields. Therefore, improving the cycle life of lead-acid batteries is a technical problem that needs to be solved. Summary of the Invention

[0004] In order to solve at least one of the above-mentioned technical problems, and to develop a positive electrode grid that improves the cycle life of a battery, this application provides a positive electrode grid, a preparation method, a positive electrode plate, and a lead-acid battery.

[0005] On the one hand, the positive electrode grid provided in this application is prepared from the following components,

[0006] Ca: 0.050wt%~0.070wt%;

[0007] Al: 0.020wt%~0.040wt%;

[0008] Sn: 1.000wt%~1.500wt%;

[0009] Re: 0.010wt%~0.030wt%;

[0010] Mg: 0.010wt%~0.020wt%;

[0011] Lead: Balance.

[0012] Optionally, in the positive electrode grid of this application, the weight ratio of Re to Mg is 1:1.

[0013] Optionally, the following impurities are present in the positive electrode grid of this application:

[0014] Fe: ≤0.0003wt%;

[0015] Sb: ≤0.0001wt%;

[0016] Ni: ≤0.0005wt%;

[0017] Cd: ≤0.0004wt%;

[0018] Bi: ≤0.0002wt%.

[0019] Secondly, this application provides a method for preparing the above-mentioned positive electrode grid, including the following steps:

[0020] S1, molten lead

[0021] First, add a portion of the prescribed amount of lead and heat it to melt the lead.

[0022] S2, Step 1: Slag Removal

[0023] Heat the mixture, add sodium nitrate and sodium hydroxide at once, and stir for 10 to 15 minutes. The lead slag will turn into yellow granules. Remove the slag.

[0024] S3, Second Step: Slag Removal

[0025] Keep the temperature constant, add sodium nitrate and sodium hydroxide again, stir for 10 to 15 minutes, remove the slag, then add lead slag reducing agent, stir for 5 to 10 minutes, stop the machine, and remove the slag.

[0026] S4, Adding metal components

[0027] Increase the temperature again, and slowly add the prescribed amounts of aluminum, magnesium, rhenium, calcium, and tin while stirring, stirring for 5 to 15 minutes;

[0028] S5, Cooling

[0029] Add the remaining lead according to the formula, cool down, and stir for 5 to 15 minutes;

[0030] S6. Sampling and Testing

[0031] After the sample passes the test, the temperature is raised, the liquid is released, and the positive electrode grid is prepared.

[0032] Optionally, in S1, the amount of lead added is 85wt% to 95wt% of the formulation amount.

[0033] Optionally, in step S2, the amount of sodium nitrate added is 0.2 wt% to 0.4 wt% of the lead formulation amount;

[0034] And / or, the amount of sodium hydroxide added is 0.2wt% to 0.4wt% of the lead formulation amount.

[0035] Optionally, in step S3, the amount of sodium nitrate added is 0.2 wt% to 0.4 wt% of the lead formulation amount;

[0036] And / or, the amount of sodium hydroxide added is 0.2 wt% to 0.4 wt% of the lead formulation amount;

[0037] And / or, the amount of lead slag reducing agent added is 0.5wt% to 1wt% of the lead formulation amount.

[0038] Optionally, in step S2, the temperature is raised to 640℃±10℃;

[0039] And / or, in S4, the temperature is raised to 690℃±10℃;

[0040] And / or, in S5, the temperature is reduced to 550℃±10℃;

[0041] And / or, in S6, the temperature is raised to 600℃~630℃.

[0042] Thirdly, this application provides a positive electrode plate, including the aforementioned positive electrode plate grid.

[0043] Fourthly, this application provides a lead-acid battery, including the aforementioned positive electrode plate.

[0044] In summary, the rhenium in this application's technical solution can improve the mechanical strength and corrosion resistance of the grid, providing excellent structural support and thus improving cycle life. Magnesium slowly precipitates during battery charging, forming magnesium sulfate together with magnesium oxide in the lead paste formulation within the deep pores of the positive electrode active material. This increases the liquid phase conductivity within the deep pores of the positive electrode, reduces liquid phase ohmic polarization, and increases the utilization rate of the positive electrode active material. The addition of rhenium can alter the surface state of the electrode plates, reducing side reactions and improving both the utilization rate of the active material and the cycle life of the battery. Furthermore, rhenium can also affect the interface layer between the electrode plates and the electrolyte, optimizing interface resistance and promoting ion transport efficiency, thereby reducing battery losses during use and improving cycle life. Detailed Implementation

[0045] The embodiments of this application are described in detail below. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in the art or in accordance with the product manual.

[0046] Example 1

[0047] In this embodiment, a positive electrode grid is prepared from the following components: Ca: 0.050 wt%; Al: 0.020 wt%; Sn: 1.000 wt%; Re: 0.010 wt%; Mg: 0.010 wt%; Lead: balance.

[0048] First, add 90 wt% of lead according to the formula, and heat it to melt the lead;

[0049] S2, Step 1: Slag Removal

[0050] The temperature was raised to 640℃, and 0.2wt% sodium nitrate and 0.2wt% sodium hydroxide of the lead formula were added at once. After stirring for 10 minutes, the lead slag turned into yellow granules. The slag was then removed.

[0051] S3, Second Step: Slag Removal

[0052] Keep the temperature constant at 640℃, add 0.2wt% sodium nitrate and 0.2wt% sodium hydroxide of the lead formula, stir for 10 minutes, remove the slag, then add 0.5wt% lead slag reducing agent of the lead formula, stir for 5 minutes, stop the machine, and remove the slag.

[0053] S4, Adding metal components

[0054] Raise the temperature again to 690℃, and slowly add the prescribed amounts of aluminum, magnesium, rhenium, calcium, and tin while stirring, and stir for 10 minutes;

[0055] S5, Cooling

[0056] Add 10 wt% lead according to the formula, cool to 550℃, and stir for 10 min;

[0057] S6. Sampling and Testing

[0058] After the sample passes the test, the temperature is raised to 600℃ and the liquid is released.

[0059] Example 2

[0060] This embodiment prepares a positive electrode grid, which differs from Embodiment 1 in that the positive electrode grid in this embodiment is prepared from the following components: Ca: 0.060 wt%; Al: 0.030 wt%; Sn: 1.000 wt%; Re: 0.010 wt%; Mg: 0.020 wt%; Lead: balance.

[0061] Example 3

[0062] This embodiment prepares a positive electrode grid, which differs from Embodiment 1 in that the positive electrode grid in this embodiment is prepared from the following components: Ca: 0.070 wt%; Al: 0.040 wt%; Sn: 1.000 wt%; Re: 0.020 wt%; Mg: 0.010 wt%; Lead: balance.

[0063] Example 4

[0064] This embodiment prepares a positive electrode grid, which differs from Embodiment 1 in that the positive electrode grid in this embodiment is prepared from the following components: Ca: 0.050wt%; Al: 0.040wt%; Sn: 1.500wt%; Re: 0.020wt%; Mg: 0.020wt%; Lead: balance.

[0065] Example 5

[0066] This embodiment prepares a positive electrode grid, which differs from Embodiment 1 in that the positive electrode grid in this embodiment is prepared from the following components: Ca: 0.060 wt%; Al: 0.030 wt%; Sn: 1.500 wt%; Re: 0.030 wt%; Mg: 0.010 wt%; Lead: balance.

[0067] Example 6

[0068] This embodiment prepares a positive electrode grid, which differs from Embodiment 1 in that the positive electrode grid in this embodiment is prepared from the following components: Ca: 0.070wt%; Al: 0.020wt%; Sn: 1.500wt%; Re: 0.030wt%; Mg: 0.020wt%; Lead: balance.

[0069] Comparative Example 1

[0070] This comparative example prepares a positive electrode grid, which differs from Example 1 in that the positive electrode grid of this comparative example is prepared from the following components: Ca: 0.050 wt%; Al: 0.020 wt%; Sn: 1.000 wt%; Re: 0.010 wt%; Mg: 0.010 wt%; Lead: balance.

[0071] Comparative Example 2

[0072] This comparative example prepares a positive electrode grid, which differs from Example 3 in that the positive electrode grid of this comparative example is prepared from the following components: Ca: 0.070 wt%; Al: 0.040 wt%; Sn: 1.000 wt%; Re: 0.020 wt%; Mg: 0.010 wt%; Lead: balance.

[0073] Comparative Example 3

[0074] This comparative example prepares a positive electrode grid, which differs from Example 5 in that the positive electrode grid of this comparative example is prepared from the following components: Ca: 0.060 wt%; Al: 0.030 wt%; Sn: 1.500 wt%; Re: 0.030 wt%; Mg: 0.010 wt%; Lead: balance.

[0075] The positive electrode grid used the positive electrode grids prepared in Examples 1 to 6 and Comparative Examples 1 to 3 above, and the negative electrode grid used a lead-calcium alloy negative electrode grid. The same preparation method was used to prepare the LDC6-400A (voltage 6V, capacity 400Ah) battery.

[0076] The electrode formula used for the positive and negative plates is: 1000kg lead powder, 110kg water, and 100kg sulfuric acid (1.4g / cm³). 3 It is prepared by adding 9kg to 11kg (positive electrode auxiliary material) / 30kg (negative electrode auxiliary material) and paste coating plate.

[0077] Lead paste additives: graphene, stannous sulfate, antimony trioxide, phosphoric acid, indium oxide, magnesium oxide, zinc oxide, and short fibers with a length of 3mm.

[0078] Negative electrode lead paste additives: lignin, barium sulfate, carbon black, and short fibers with a length of 3mm.

[0079] Except for short fibers, the positive and negative electrode additives are ground into powder by ball milling and mixed evenly. The emulsion is prepared by mixing the additives and water in a ratio of 1:4.

[0080] Mixing: Add one ton of lead powder and short fibers to the mixing machine. Add the auxiliary material emulsion to the micro stirring funnel and slowly add it to the mixing machine through the nozzle at the bottom of the funnel. Dry mix for 5 minutes, then add water quickly for ≤2 minutes. Wet mix for 5 minutes, then add acid slowly for about 13 minutes. After adding acid, the temperature rises. The temperature of the positive electrode mixture rises to 72℃ and then cools down. The peak temperature of the negative electrode mixture is <65℃. After adding acid, stir for 10 to 15 minutes to finish mixing.

[0081] The above-mentioned batteries were subjected to a 100% DOD discharge cycle test (25°C).

[0082] The testing method is as follows:

[0083] 1. Let stand for 1 hour;

[0084] 2. Discharge at 68.4A until 1.75V / cell is reached;

[0085] 3. Charge at a constant voltage of 2.43V / cell with a current limit of 68.4A for 10 hours;

[0086] 4. Repeat steps 1-3 until the battery discharge capacity is below 0.5C, then terminate the test.

[0087] The test results are shown in Table 1.

[0088] Table 1

[0089] As can be seen from Examples 1 to 6, Comparative Examples 1 to 3, and Table 1 above, the battery using the positive grid prepared in this application has a cycle life increased by more than 44% compared to the battery prepared using Comparative Examples 1 to 3. This indicates that the addition of rhenium to the positive grid and the limiting of the weight ratios of elements such as calcium, aluminum, tin, rhenium, magnesium, and lead in this application can significantly improve the cycle life of the battery.

[0090] Further analysis of Table 1 shows that the cycle number of the batteries corresponding to Examples 1 and 4 is significantly higher than that of other examples. In order to verify whether it is related to the rhenium / magnesium weight ratio, the inventors made the following Examples 7 to 10, as detailed below.

[0091] Example 7

[0092] This embodiment is used to prepare a positive electrode grid. The difference from Embodiment 2 is that the positive electrode grid in this embodiment is prepared from the following components: Ca: 0.060 wt%; Al: 0.030 wt%; Sn: 1.000 wt%; Re: 0.010 wt%; Mg: 0.010 wt%; Lead: balance.

[0093] Example 8

[0094] This embodiment is used to prepare a positive electrode grid. The difference from Embodiment 3 is that the positive electrode grid in this embodiment is prepared from the following components: Ca: 0.070wt%; Al: 0.040wt%; Sn: 1.000wt%; Re: 0.020wt%; Mg: 0.020wt%; Lead: balance.

[0095] Example 9

[0096] This embodiment is used to prepare a positive electrode grid. The difference from Embodiment 5 is that the positive electrode grid in this embodiment is prepared from the following components: Ca: 0.060wt%; Al: 0.030wt%; Sn: 1.500wt%; Re: 0.030wt%; Mg: 0.030wt%; Lead: balance.

[0097] Example 10

[0098] This embodiment is used to prepare a positive electrode grid. The difference from Embodiment 6 is that the positive electrode grid in this embodiment is prepared from the following components: Ca: 0.070wt%; Al: 0.020wt%; Sn: 1.500wt%; Re: 0.030wt%; Mg: 0.030wt%; Lead: balance.

[0099] The positive electrode grid was prepared using the positive electrode grids prepared in Examples 7 to 10 above, and an LDC6-400A (6V 400Ah) battery was prepared according to the above method. The above battery was subjected to a 100% DOD discharge cycle test (25°C); the test results are shown in Table 2.

[0100] Table 2

[0101] Examples 7 to 10, based on Examples 2 / 3 / 5 / 6, adjusted the rhenium / magnesium addition amount to achieve a rhenium / magnesium weight ratio of 1:1. The resulting positive electrode grids were assembled into batteries. These batteries achieved over 700 cycle times in testing, representing an improvement of approximately 55% compared to Comparative Examples 1 to 3, and approximately 7% compared to Examples 2 / 3 / 5 / 6. Therefore, it can be seen that adjusting the rhenium / magnesium weight ratio to 1:1 in the technical solution of this application can significantly improve the cycle life of the battery.

[0102] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A positive electrode grid, wherein, It is prepared from the following components. Ca: 0.050wt%~0.070wt%; Al: 0.020wt%~0.040wt%; Sn: 1.000wt%~1.500wt%; Re: 0.010wt%~0.030wt%; Mg: 0.010wt%~0.020wt%; Lead: Balance.

2. The positive electrode grid according to claim 1, wherein, The weight ratio of Re to Mg is 1:

1.

3. The positive electrode grid according to claim 1, wherein, The following impurity contents are: Fe: ≤0.0003wt%; Sb: ≤0.0001wt%; Ni: ≤0.0005wt%; Cd: ≤0.0004wt%; Bi: ≤0.0002wt%.

4. A method for preparing the positive electrode grid according to claim 1, wherein, Includes the following steps: S1, molten lead First, add a portion of the prescribed amount of lead and heat it to melt the lead. S2, Step 1: Slag Removal Heat the mixture, add sodium nitrate and sodium hydroxide at once, and stir for 10 to 15 minutes. The lead slag will turn into yellow granules. Remove the slag. S3, Second Step: Slag Removal Keep the temperature constant, add sodium nitrate and sodium hydroxide again, stir for 10 to 15 minutes, remove the slag, then add lead slag reducing agent, stir for 5 to 10 minutes, stop the machine, and remove the slag. S4, Adding metal components Increase the temperature again, and slowly add the prescribed amounts of aluminum, magnesium, rhenium, calcium, and tin while stirring, stirring for 5 to 15 minutes; S5, Cooling Add the remaining lead according to the formula, cool down, and stir for 5 to 15 minutes; S6. Sampling and Testing After the sample passes the test, the temperature is raised, the liquid is released, and the positive electrode grid is prepared.

5. The method for preparing the positive electrode grid according to claim 4, wherein, In S1, the amount of lead added is 85wt% to 95wt% of the formula amount.

6. The method for preparing the positive electrode grid according to claim 4, wherein, In step S2, the amount of sodium nitrate added is 0.2 wt% to 0.4 wt% of the lead formulation amount; And / or, the amount of sodium hydroxide added is 0.2wt% to 0.4wt% of the lead formulation amount.

7. The method for preparing the positive electrode grid according to claim 4, wherein, In step S3, the amount of sodium nitrate added is 0.2 wt% to 0.4 wt% of the lead formulation amount; And / or, the amount of sodium hydroxide added is 0.2 wt% to 0.4 wt% of the lead formulation amount; And / or, the amount of lead slag reducing agent added is 0.5wt% to 1wt% of the lead formulation amount.

8. The method for preparing the positive electrode grid according to claim 4, wherein, In step S2, the temperature is raised to 640℃±10℃; And / or, in S4, the temperature is raised to 690℃±10℃; And / or, in S5, the temperature is reduced to 550℃±10℃; And / or, in S6, the temperature is raised to 600℃~630℃.

9. A positive electrode plate, wherein, Includes the positive electrode grid as described in claim 1.

10. A lead-acid battery, wherein, Includes the positive electrode plate as described in claim 9.

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