Pretreatment method of unformed plate for container formation

Abstract

The invention provides a pretreatment method of an unformed plate for container formation, which comprises the following steps: treating a cured dry unformed plate into a wet unformed plate, and wrapping the wet unformed plate. The invention further provides a manufacturing method of the lead-acid storage battery. According to the pretreatment method of the unformed plate for internal formation, the corrosion layer of the plate can form a skeleton structure during formation of the lead-acid storage battery, so that the service life of the battery is ensured.

Description

Technical Field

[0001] The invention relates to the field of lead-acid battery manufacturing, in particular to a pretreatment method for green plates used for internal formation. Background Art

[0002] At present, the manufacturing of internally formed lead-acid batteries includes the following steps: mixing paste, coating plates, curing, plate wrapping, slotting, welding, sealing, and forming. In order to ensure the binding force of the active material, i.e., the lead paste, the water content of the plate after curing is usually less than 0.2%, which leads to the formation of considerable pores in the plate, including pores formed in the lead paste and pores formed in the corrosion layer generated at the contact part between the lead paste and the grid. At present, the plate wrapped in the slot is all cured dry plate. Since the cured dry plate will generate a corrosion layer at the contact part between the grid and the active material, the corrosion layer is usually composed of lead oxide. , 3BS. After the dry plate is packed into the slot, during the formation, sulfuric acid will enter the pores of the corrosion layer due to the addition of acid. Sulfuric acid will quickly react with the lead oxide and 3BS in the corrosion layer to generate lead sulfate in the corrosion layer. When it is electrified, the lead sulfate generated in the corrosion layer through the electrochemical reaction is difficult to transform. Even if it is transformed, it can only be partially transformed into β-PbO2. On the one hand, the electrical conductivity of the corrosion layer will decrease due to the large resistance of lead sulfate. On the other hand, due to the poor strength of the generated β-PbO2, it is difficult to play the role of a skeleton connecting the grid and the active material, thus limiting the battery life. The corrosion layer of the negative plate will generate sponge lead, which has poor strength and is difficult to play the role of a skeleton connecting the grid and the active material, thus limiting the battery life. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a pretreatment method for green plates for internalization, comprising: treating the solidified dry green plates into wet green plates, and wrapping the wet green plates.

[0004] Furthermore, the method of treating the cured dry green plates to become wet green plates is to treat the cured dry green plates with water.

[0005] Furthermore, the method of treating the solidified dry green plates to become wet green plates is to treat the solidified dry green plates with an aqueous solution.

[0006] Furthermore, the aqueous solution is a sulfuric acid aqueous solution or an alkali aqueous solution.

[0007] Furthermore, the density of the aqueous sulfuric acid solution is between 1.00 g / mL and 1.20 g / mL (25° C.).

[0008] Furthermore, the aqueous solution is a sulfate aqueous solution.

[0009] Furthermore, the sulfate aqueous solution is a stannous sulfate aqueous solution.

[0010] Furthermore, the stannous sulfate aqueous solution is a stannous sulfate aqueous solution formed by dissolving tin in a dilute sulfuric acid aqueous solution.

[0011] Furthermore, the aqueous solution is a mixed aqueous solution of sulfate and a low-density sulfuric acid aqueous solution.

[0012] Furthermore, the mixed aqueous solution is a mixed aqueous solution of bismuth sulfate and a low-density sulfuric acid aqueous solution or a mixed aqueous solution of antimony sulfate and a low-density sulfuric acid aqueous solution.

[0013] Furthermore, the treatment method is soaking or pouring.

[0014] Furthermore, the soaking or pouring time is until no bubbles emerge from the surface of the electrode plate.

[0015] Furthermore, before the wet-grown plates are wrapped, a step of drying the wet-grown plates is also included.

[0016] The present invention also protects a method for manufacturing a lead-acid battery, which includes putting the wet green plates obtained by the pretreatment method of the green plates for internalization into a battery tank and adding acid for oxidation.

[0017] Furthermore, during the acidification, the density of the sulfuric acid aqueous solution added is higher than the density of the sulfuric acid aqueous solution when the cured dry green plates are immersed or poured.

[0018] Furthermore, the density of the aqueous sulfuric acid solution when the cured dry green plates are immersed or poured is between 1.04 g / mL and 1.08 g / mL (25° C.), and the density of the aqueous sulfuric acid solution added during the acidification is between 1.23 and 1.27 g / mL (25° C.).

[0019] The method for pretreating the green plate for internal formation of the present invention can form a skeleton structure on the corrosion layer of the plate during formation to ensure the battery life. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with specific embodiments.

[0021] The present invention discloses a pretreatment method for green plates for internalization, comprising: treating the solidified dry green plates into wet green plates, and wrapping the wet green plates. The solidified dry green plates can be treated with water or with an aqueous solution. The treatment method is preferably soaking or pouring. The aqueous solution can be a sulfuric acid aqueous solution. A high-density sulfuric acid aqueous solution will inevitably cause sulfuric acid to enter the pores of the corrosion layer, thereby producing an adverse effect. The density of the sulfuric acid aqueous solution is preferably between 1.00 g / mL and 1.20 g / mL (25°C), preferably between 1.04 g / mL and 1.08 g / mL (25°C). The density of the sulfuric acid aqueous solution reaches 1.20 g / mL (25°C) or more, which will cause damage to the corrosion layer. A low-density sulfuric acid aqueous solution with a density lower than 1.20 g / mL (25°C) is selected for soaking or pouring. , which can better achieve the goal of completely consuming sulfuric acid to generate lead sulfate through chemical reaction on the surface of the active material as much as possible, thereby ensuring that sulfuric acid does not enter the pores of the corrosion layer as much as possible, thereby avoiding the generation of lead sulfate in the corrosion layer, thereby achieving the purpose of only allowing water to enter the pores of the corrosion layer as much as possible. In addition, the chemical reaction on the surface of the active material generates lead sulfate, and the volume increases, resulting in the smaller pores inside the active material, which can slow down the speed at which the acid added to the relatively high-density sulfuric acid aqueous solution enters the active material during formation, thereby ensuring that water reaches the bottom of the active material faster, that is, the part close to the grid. During formation, an electrochemical reaction first generates a skeleton structure to ensure the support of the bottom of the active material. α-PbO2 can be generated at the bottom of the active material of the positive plate, and skeleton lead can be generated at the bottom of the active material of the negative plate;In addition, since the lead sulfate generated by the chemical reaction on the surface of the active material by immersion or pouring is relatively uniform, the uniformity of the acid added to the relatively high-density sulfuric acid aqueous solution entering the interior of the active material during the formation can be improved. Again, since part of the lead sulfate is pre-generated on the surface of the active material through treatment, the heat generated during the formation is reduced, and the skeleton structure generated by the electrochemical reaction of the corrosion layer and the skeleton structure generated by the electrochemical reaction at the bottom of the active material are both endothermic reactions, which can reduce the difficulty of temperature control during the formation and greatly improve the formation efficiency. In addition to the low-density sulfuric acid aqueous solution, the aqueous solution of the present invention can also be a sulfate aqueous solution, such as: stannous sulfate aqueous solution, the stannous sulfate aqueous solution can be a stannous sulfate aqueous solution formed by stannous sulfate dissolved in water, the stannous sulfate aqueous solution can also be a stannous sulfate aqueous solution formed by stannous sulfate dissolved in dilute sulfuric acid, preferably a stannous sulfate aqueous solution formed by tin dissolved in dilute sulfuric acid aqueous solution, so that In order to reduce the production cost, due to the presence of divalent tin, the divalent tin will enter the corrosion layer. During the battery charging and discharging process, the conductivity of the corrosion layer is improved, and the thickening of the corrosion layer can be prevented. In addition, tin will also enter the active material, improving the conductivity of the active material. In addition, due to immersion or spraying, the uniform distribution of tin in the active material can be better achieved, further improving the conductivity. That is, the metal cations of the sulfate aqueous solution can enter the active material in the form of ions in the form of sulfate aqueous solution through immersion or spraying and can be evenly distributed in the active material. On the one hand, it can avoid the uneven problem of adding in the form of metal oxides when mixing the paste, and also avoid the influence on the battery performance caused by the addition of metal oxides when mixing the paste, which requires a long time of charging and discharging to be converted into metal cations and enter the active material, such as: metal cations in the active material: bismuth ions, antimony ions, etc. In addition, in order to adjust the solubility of sulfate as needed, the aqueous solution of the present invention can also be a mixed aqueous solution of sulfate and low-density sulfuric acid aqueous solution, such as a mixed aqueous solution of bismuth sulfate and low-density sulfuric acid aqueous solution or a mixed aqueous solution of antimony sulfate and low-density sulfuric acid aqueous solution, etc., which can achieve the technical effects of water or dilute sulfuric acid aqueous solution, and can also achieve uniform distribution of metal cations in the active material and avoid the effect on battery performance caused by adding metal oxides during paste, which requires long-term charging and discharging to convert into metal cations and enter the active material. ;

[0022] In order to process the solidified dry-green plate into a wet-green plate and achieve a good effect, that is, water can enter the pores of the corrosion layer well, the positive plate is treated as follows: the present invention soaks or pours the solidified dry-green plate in water at a temperature of 5°C to 50°C for 5 to 80 minutes, preferably until no bubbles emerge on the surface of the plate, so that the water can completely fill the pores of the corrosion layer, and after the soaking or pouring, the wet-green plate is obtained, and the wet-green plate is wrapped. Alternatively, the present invention soaks or pours the solidified dry-green plate in dilute sulfuric acid, the density of which is preferably less than 1.20g / mL, between 1.04g / mL-1.08g / mL, at a temperature of 5°C to 50°C for 5 to 80 minutes, preferably until no bubbles emerge on the surface of the plate, and after the soaking or pouring, the wet-green plate is obtained, and the wet-green plate is wrapped. Alternatively, in a similar manner, the present invention soaks or pours the solidified dry green plates through sulfate, such as stannous sulfate; or in a similar manner, the present invention soaks or pours the solidified dry green plates through a mixed aqueous solution, such as a mixed aqueous solution of bismuth sulfate and a low-density sulfuric acid aqueous solution or a mixed aqueous solution of antimony sulfate and a low-density sulfuric acid aqueous solution, etc. The density of dilute sulfuric acid in the present invention refers to the density at room temperature 25°C.

[0023] The aqueous solution used to process the solidified dry green plates into wet green green plates in the present invention can be a neutral, weakly acidic or weakly alkaline aqueous solution with a pH value, and the technical effects of the present invention can be achieved.

[0024] The negative electrode plate can also be selectively processed in a similar process to the positive electrode plate as needed.

[0025] The present invention processes the solidified dry-green plates into wet-green plates, that is, after the lead paste bonding force is formed after solidification, the dry-green plates with the lead paste bonding force are processed into wet-green plates, so that the lead paste bonding force of the wet-green plates can be guaranteed at this time, and the purpose of water entering the corrosion layer can be achieved at the same time, thereby achieving the technical effect of the present invention.

[0026] The present invention also protects a method for manufacturing a lead-acid battery, comprising placing the wet green plates obtained by the pretreatment method of the green plates for internal formation of the present invention into a battery slot for formation. That is, the solidified dry green plates are processed into wet green plates, the wet green plates are packaged, the packaged wet green plates are placed into a battery slot, and acid is added for formation. The treatment method is preferably soaking or pouring. In order to ensure that the open circuit voltage requirement of the lead-acid battery is met, the density of the sulfuric acid aqueous solution added during formation should use a high-density acid, that is, it should be higher than the density of the sulfuric acid aqueous solution during soaking or pouring, and preferably between 1.23-1.27g / mL, such as: 1.25g / mL. In addition, before the solidified dry green plates are processed into wet green plates, the process may also include mixing paste, coating plates, and curing.

[0027] After the wet plate is wrapped into the tank, when acid is added for formation, since water or water in the aqueous solution enters the pores of the corrosion layer in advance, when sulfuric acid aqueous solution is added for formation, sulfuric acid will hardly enter the corrosion layer. When electrification is applied, since the corrosion layer is in a neutral or alkaline environment, the corrosion layer will first generate α-PbO2 in the corrosion layer of the positive plate through electrochemical reaction. α-PbO2 has high strength and is relatively stable, which ensures the skeleton effect of the grid and the active material, thereby improving the life of the battery, and also avoids the problem of decreased conductivity caused by the generation of lead sulfate in the corrosion layer. Similarly, the corrosion layer of the negative plate will generate strong skeleton lead, which ensures the skeleton effect of the grid and the active material, thereby improving the life of the battery, and also avoids the problem of decreased conductivity caused by the generation of lead sulfate in the corrosion layer. In addition, the skeleton structure generated by the electrochemical reaction of the corrosion layer and the skeleton structure generated by the electrochemical reaction at the bottom of the active material are both endothermic reactions, which can reduce the difficulty of temperature control during formation and help improve the formation efficiency.

[0028] In addition, the curing of the present invention at least includes a drying process, and further may include a recrystallization process and a free lead oxidation process. The cured dry green plate of the present invention refers to the green plate obtained after the paste grid is dried. The wet green plate of the present invention refers to the water-containing plate obtained after the cured dry green plate is treated, that is, the water content of the wet green plate at this time is higher than the water content of the cured dry green plate, and it can be a water-containing plate after immersion or pouring treatment. The water content of the wet green plate can exceed 3%, preferably more than 5%. In addition, the lead paste bonding force of the wet green plate at this time is higher than the lead paste bonding force of the green plate before curing after the coating. In addition, before the wet green plate of the present invention is wrapped, while ensuring the water content, it is best to dry the wet green plate, that is, to ensure that the surface of the wet green plate is preferably not wrapped in a dripping state, so as to reduce the risk of short circuit that may be caused after the wrapped plate is put into the slot.

[0029] The present invention is preferably carried out in a vacuum environment to process the solidified dry-green plates into wet-green plates. In this way, when a plurality of solidified dry-green plates are processed simultaneously, the problem of inconsistent water content of different plates due to plate placement, temperature differences, etc. can be avoided, thereby ensuring the consistency of the plates and further ensuring the battery life.

[0030] Taking a 48V20AH lead-acid battery as an example, except for the different treatment methods of the cured dry green plates, other conditions are exactly the same.

[0031] The lead-acid battery prepared by packaging the solidified dry green plates, putting them into slots and forming them was subjected to a cycle life test, and the results were as follows: 481 times.

[0032] The cured dry green plates were soaked in water, wrapped, put into slots, and formed into a lead-acid battery, and the cycle life test was carried out. The result was as follows: 813 times.

[0033] The cured dry green plates were immersed in dilute sulfuric acid solution, packaged, put into the tank, and formed into a lead-acid battery. The cycle life test was carried out and the results were as follows: 890 times.

[0034] The cured dry green plates were immersed in stannous sulfate solution, then wrapped, put into a tank, and chemically formed to prepare a lead-acid battery, which was tested for cycle life. The results were as follows: 910 times.

[0035] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A method for pretreating green plates for internalization, characterized in that: include: The cured dry green plates are processed into wet green plates, and the wet green plates are packaged.

2. A method for pretreating green plates for internal formation as claimed in claim 1, characterized in that: The method of treating the cured dry green plates to become wet green plates is to treat the cured dry green plates with water.

3. A method for pretreating green plates for internal formation as claimed in claim 1, characterized in that: The method of treating the cured dry green plate to become a wet green plate is to treat the cured dry green plate with an aqueous solution.

4. A method for pretreating green plates for internal formation as claimed in claim 3, characterized in that: The aqueous solution is a sulfuric acid aqueous solution or an alkali aqueous solution.

5. A method for pretreating green plates for internal formation as claimed in claim 4, characterized in that: The density of the aqueous sulfuric acid solution is between 1.00 g / mL and 1.20 g / mL.

6. A method for pretreating green plates for internal formation as claimed in claim 3, characterized in that: The aqueous solution is a sulfate aqueous solution.

7. A method for pretreating green plates for internal formation as claimed in claim 6, characterized in that: The sulfate aqueous solution is a stannous sulfate aqueous solution.

8. A method for pretreating green plates for internal formation as claimed in claim 7, characterized in that: The stannous sulfate aqueous solution is a stannous sulfate aqueous solution formed by dissolving tin in a dilute sulfuric acid aqueous solution.

9. A method for pretreating green plates for internal formation as claimed in claim 3, characterized in that: The aqueous solution is a mixed aqueous solution of sulfate and a low-density sulfuric acid aqueous solution.

10. A method for pretreating green plates for internal formation as claimed in claim 9, characterized in that: The mixed aqueous solution is a mixed aqueous solution of bismuth sulfate and a low-density sulfuric acid aqueous solution or a mixed aqueous solution of antimony sulfate and a low-density sulfuric acid aqueous solution.

11. A method for pretreating green plates for internal formation as claimed in any one of claims 1 to 10, characterized in that: The treatment method is soaking or pouring.

12. A method for pretreating green plates for internal formation as claimed in any one of claims 1 to 10, characterized in that: The treatment is carried out in a vacuum environment.

13. A method for pretreating green plates for internal formation as claimed in any one of claims 1 to 10, characterized in that: Before the wet-grown plates are packaged, the method further includes a step of drying the wet-grown plates.

14. A method for manufacturing a lead-acid battery, characterized in that: The wet green plates obtained by the pretreatment method of green plates for internalization as claimed in any one of claims 1 to 10 are placed in a battery tank and acidified.

15. A method for manufacturing a lead-acid battery as claimed in claim 14, characterized in that: During the acidification, the density of the added sulfuric acid aqueous solution is higher than the density of the sulfuric acid aqueous solution when the solidified dry green plates are immersed or poured.

16. A method for manufacturing a lead-acid battery as claimed in claim 15, characterized in that: The density of the aqueous sulfuric acid solution when the cured dry green plates are immersed or poured is between 1.04 g / mL and 1.08 g / mL. During the acidification, the density of the aqueous sulfuric acid solution added is between 1.23 and 1.27 g / mL.