A valve regulated lead-acid battery plate curing and drying process

Abstract

This invention discloses a valve-regulated lead-acid battery plate curing and drying process, belonging to the field of lead-acid batteries. The process includes: keeping the plates moist at a temperature of 65±5℃, relative humidity of 98±2%, and pressure of 0.2~0.3 MPa without turning on the circulating air; then keeping them moist at a temperature of 60±5℃ and relative humidity of 90±2%, while simultaneously turning on the circulating air; iterating multiple cycles with a positive pressure stage, a static stage, a negative pressure stage, and internal air circulation as one cycle to achieve oxidation of the plates after high humidity treatment; the positive pressure is 0.2~0.3 MPa, the negative pressure is -0.3~-0.2 MPa, and the air velocity in the internal air circulation is 0.3~0.6 m / s; and then drying the oxidized plates. This invention solves the technical pain points of high local water content and excessive free lead content, significantly improving the consistency of the finished battery.

Description

Technical Field

[0001] This invention belongs to the field of lead-acid batteries, specifically relating to a process for curing and drying the plates of a valve-regulated lead-acid battery. Background Technology

[0002] In the manufacturing process of lead-acid batteries, plate curing and drying is one of the key processes. After the lead paste is applied to the grid, only through a curing and drying process can the lead paste particles connect to form a continuous and solid skeleton and adhere tightly to the grid. The quality of plate curing directly affects the battery's performance indicators and service life. Currently, the prominent problems with plates include poor plate strength and inconsistent plate performance.

[0003] The curing and drying of lead-acid battery plates is divided into three stages: a high-temperature and high-humidity stage, an active material oxidation and water loss stage, and a drying stage. The oxidation process mainly completes: (1) oxidation of free lead, increasing the capacity of the active material; (2) oxidation of lead on the surface of the grid ribs, increasing the bonding force between the grid ribs and the active material; and (3) recrystallization of basic lead sulfate, increasing the strength of the plate. The drying process mainly completes the drying of the plate, enhancing its strength and forming porous electrodes. Therefore, the active material oxidation and water loss stage is particularly important in the curing and drying process.

[0004] There are two main methods for curing lead-acid battery plates: the first is the conventional curing process, which relies on temperature and humidity control during the curing stage to directly drive the internal moisture of the plate outward, and simultaneously complete the dehydration and oxidation reactions; the second is the alternating positive and negative pressure curing process, which achieves the dehydration and oxidation of the plate by alternating positive pressure to compact the plate pores and negative pressure to accelerate the evaporation of moisture. For example, the invention patent with publication number CN108711610A discloses a lead-acid battery plate curing and drying process, which includes two stages: oxidation and drying. The oxidation stage includes the following steps in sequence: (1) reducing the pressure to 0.03~0.05 MPa, maintaining the temperature at 50~55℃, reducing the humidity to 70%~80%, and maintaining for 15-20 min; (2) introducing ozone, increasing the pressure to 0.2~0.3 MPa, increasing the temperature to 80℃~85℃ and the relative humidity to 90%~95%, and maintaining for 3~4 h; (3) reducing the temperature to 60℃~65℃ and the relative humidity to 85%~90%, increasing the pressure to 0.3~0.5 MPa, and maintaining for 3~5 h; (4) reducing the temperature to 55℃~60℃, the relative humidity to 70%~80%, and the pressure to 0.2~0.3 MPa, and maintaining for 4~6 h. However, both of the above curing methods share a common problem of curing dead zones during actual operation. Specifically, this manifests as low dehydration efficiency in localized areas, resulting in high deviations in water content and free lead content in the electrode plates even at the end of the curing process. Subsequent dehydration can only be completed through the drying stage, along with partial oxidation reactions, ultimately leading to significant performance dispersion among electrode plates from the same batch.

[0005] Chinese patent CN112467090A discloses a curing and drying process for the positive electrode plate of a start-stop battery. In the oxidation stage, it employs a pulsed alternating curing process with positive pressure (0.2~0.3 MPa) and negative pressure (-0.1~-0.2 MPa), using negative pressure dehumidification to reduce humidity. Furthermore, in the pulsed curing stages, the wind speed is 0 in the first stage, 0.5~1 m / s in the second stage, 0.5~1 m / s in the third stage, 1~1.5 m / s in the fourth stage, and 1.5~2.5 m / s in the fifth stage. While this process initially solves the problems of uneven curing and dead zones, the internal air circulation accompanying the alternating positive and negative pressure pulsed curing process, and the unidirectional increasing wind speed, easily leads to the rapid formation of a dense layer on the electrode plate surface, preventing the smooth expulsion of internal moisture. This can easily cause internal cracks or peeling of active material during later drying. Moreover, the electrode plate surface is constantly under tension during continuous drying, which can easily cause the electrode plate to crack. Summary of the Invention

[0006] Traditional positive and negative pressure curing or atmospheric pressure curing methods often result in airflow dead zones in the inner layers and corners of the plate stack, preventing timely moisture removal and oxygen penetration. This leads to localized high water content and excessive free lead content in these curing dead zones, as well as significant differences in moisture content and oxidation degree among plates from the same batch, resulting in high dispersion in core indicators such as capacity output after battery assembly. This invention provides a valve-regulated lead-acid battery plate curing and drying process. During the curing and oxidation stage, a coupled positive pressure-negative pressure-internal air circulation process is employed. The alternation sequence of these three processes is clearly defined, and precise control of pressure and internal air circulation wind speed parameters achieves pressure difference-driven airflow circulation and material transfer channels throughout the curing chamber, directly acting on the inner layers and corners of the plate stack—traditional curing dead zones—ensuring uniform curing of the plates in their unformed state. This solves the technical pain points of localized high water content and excessive free lead content, significantly improving the consistency of the finished battery.

[0007] The present invention provides a curing and drying process for valve-regulated lead-acid battery plates, comprising the following steps: (1) High humidity stage: In the first stage, the plates are kept moist at a temperature of 65±5℃, relative humidity of 98±2%, and pressure of 0.2~0.3MPa without turning on the circulating air; In the second stage, the plates that have been moisturized in the first stage are kept moist at a temperature of 60±5℃ and a relative humidity of 90±2%, while the circulating air is turned on simultaneously. (2) Oxidation stage: The positive pressure stage, static stage, negative pressure stage and internal air circulation are performed in sequence as a cycle, and multiple cycles are executed iteratively to achieve oxidation of the plate after high humidity treatment; wherein, the positive pressure is 0.2~0.3 MPa, the negative pressure is -0.3~-0.2 MPa, and the air velocity of the internal air circulation is 0.3~0.6 m / s; (3) Drying stage: Dry the oxidized plates.

[0008] Unlike existing technologies that involve increasing airflow velocity throughout the curing process, the electrode curing and drying process provided by this invention follows a three-dimensional dynamic coupling mechanism in the oxidation stage, employing a specific sequence of positive pressure replenishment, negative pressure suction, and internal airflow circulation. During the positive pressure replenishment stage, oxygen is added while reshaping the pore structure of the electrode, creating channels for subsequent dehydration. During the negative pressure suction stage, a concentration difference is created through pressure differential during dehydration, driving oxygen penetration and moisture migration, thereby removing deep-seated moisture and resulting in tighter contact between lead paste particles. This alternation of positive and negative pressure avoids external dryness and internal moisture, allowing moisture to migrate uniformly from the grid interface to the surface in a gradient, resulting in a more consistent moisture content distribution on the cured electrode. Furthermore, after the positive and negative pressure stages, the internal air circulation is connected. By introducing the coordinated control of pressure timing and airflow field, the temperature and humidity gradient in the curing chamber is eliminated by forced convection, thereby achieving circulation homogenization of the microstructure of the electrode plate, eliminating stress concentration, avoiding electrode plate cracking, and completely solving the curing dead zone.

[0009] Preferably, in step (1), the moisturizing time in the first stage is 3 hours; The second stage of moisturizing lasts for 12 hours.

[0010] Preferably, in step (1), the circulating wind speed in the second stage is 0.1~0.3 m / s.

[0011] Preferably, in step (2), the settling time is 1 to 3 minutes.

[0012] Setting a resting stage between the positive and negative pressure stages is equivalent to giving the electrode a stress buffer window, preventing sudden pressure changes from causing instantaneous tensile and compressive stress inside the electrode, which could lead to electrode cracking. Furthermore, the dynamic process of pressure-relaxation-pressure helps to form a uniform microporous structure, ensuring both electrolyte permeability and the strength of the active material.

[0013] Preferably, step (2) is iterated for 90 to 95 cycles to achieve oxidation of the electrode plate after high humidity treatment.

[0014] Preferably, the temperature of the oxidation stage in step (2) is 65±5℃ and the relative humidity is 25±5%.

[0015] Preferably, in step (2), the positive pressure treatment time is 3~4 min, the negative pressure treatment time is 2~3 min, and the internal air circulation treatment time is 3~4 min.

[0016] Preferably, the drying stage in step (3) includes two stages, with the temperature of the first drying stage being 80±1℃ and the relative humidity being 5%-10%; The temperature for the second drying stage is 40±1℃, and the relative humidity is 5%-10%.

[0017] More preferably, the circulating air volume in the first drying stage is 7~9 m / s.

[0018] Preferably, the drying time for the first drying stage is 14-16 hours, and the drying time for the second drying stage is 1-1.5 hours.

[0019] On the other hand, the present invention also provides a valve-regulated lead-acid battery electrode plate prepared by the aforementioned valve-regulated lead-acid battery electrode plate curing and drying process.

[0020] On the other hand, the present invention also provides the application of valve-regulated lead-acid battery plates in the preparation of valve-regulated lead-acid batteries.

[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) In the critical oxidation period when the electrode lead paste is not fully set, the present invention simultaneously introduces negative pressure dehydration and internal air circulation for uniform humidification, so that the three core functions of dehydration, oxygen replenishment and homogenization are completed efficiently and synergistically in the same stage, avoiding the technical limitations of drying after electrode settling in traditional processes, and the difficulty in improving the curing dead corner.

[0022] (2) Process synergy mechanism: This invention adopts a positive pressure-negative pressure-air internal circulation alternating coupling process in the curing oxidation stage, clarifies the alternation sequence of the three, and combines the precise parameter matching and alternation logic of positive pressure-negative pressure-air internal circulation to clarify the parameter range of positive pressure oxygen supplementation, negative pressure dehydration, and air internal circulation uniform humidification. The pressure difference drives oxygen penetration and moisture migration, while relying on air circulation to eliminate the gradient in the curing chamber area, forming a full-domain material transfer channel driven by pressure and airflow.

[0023] (3) Targeted solution: This invention utilizes the forced airflow of internal wind circulation to cover the blind area, combined with the alternating positive and negative pressure suction-pressure replenishment effect, to directly solve the problem of high local water content and insufficient oxidation of free lead from the root cause, realize the integration of oxidation-dehydration-homogenization, ensure that the electrode plate completes uniform solidification in the unshaped state, and significantly improve the consistency of the finished battery. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and comparative examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] To make the above-mentioned objectives, features and advantages of the present invention clearer and easier to understand, the following detailed description will be provided in conjunction with specific embodiments.

[0026] Example 1 1. Positive electrode plate curing: (1) High humidity stage: The 6-DZF-20 positive electrode plate prepared by coating is placed in the curing chamber, and the temperature is kept at 68℃ and the relative humidity is 99±1%, without turning on the circulating air; Maintain a relative humidity of 99±1% and a pressure of 0.25 MPa for 3 hours; then maintain this pressure and reduce the temperature to 61℃ within 12 hours, controlling the wind speed at 0.2 m / s. After completion, proceed to the oxidation stage.

[0027] (2) Oxidation stage: Set a small cycle frequency, with the positive pressure stage, negative pressure stage and internal air circulation performed in sequence as a small cycle. There is also a static stage between the positive pressure stage and the negative pressure stage. The time of the positive pressure stage is 3.5 min, the time of the static stage is 1 min, the time of the negative pressure stage is 2.5 min, and the time of the internal air circulation is 3.5 min. The curing chamber temperature was reduced to 57.5℃ and maintained within 2 hours, the relative humidity was reduced to 25%, the positive pressure was 0.25 MPa, and the negative pressure was -0.25 MPa. Multiple small cycles were iteratively executed for a total of 16 hours, while the internal circulation wind speed was controlled at 0.45 m / s to complete the oxidation stage.

[0028] (3) Drying stage: Maintain the temperature at 80±1℃, reduce the relative humidity to 7%, run for 15 hours with a circulating air volume of 8 m / s, gradually reduce the drying temperature to 40±1℃ and run for another hour, and restore the plate to normal temperature to complete the positive plate curing and drying process.

[0029] 2. Negative electrode plate curing: (1) High humidity stage: The 6-DZF-20 negative electrode plate prepared by coating is placed in the curing chamber, and the temperature is maintained at 62℃ and the relative humidity is 99±1%, without turning on the circulating air; Maintain a relative humidity of 99±1% and a pressure of 0.25 MPa for 3 hours; then maintain this pressure and reduce the temperature to 57℃ within 12 hours, while controlling the wind speed at 0.2 m / s. After completion, proceed to the oxidation stage.

[0030] (2) Oxidation stage: Set a small cycle frequency, with the positive pressure stage, negative pressure stage and internal air circulation performed in sequence as a small cycle. There is also a static stage between the positive pressure stage and the negative pressure stage. The time of the positive pressure stage is 3.5 min, the time of the static stage is 1 min, the time of the negative pressure stage is 2.5 min, and the time of the internal air circulation is 3.5 min. The curing chamber temperature was reduced to 52.5℃ and maintained within 2 hours, the relative humidity was reduced to 25%, the positive pressure was 0.25 MPa, and the negative pressure was -0.25 MPa. Multiple small cycles were iteratively executed for a total of 16 hours, while the internal circulation wind speed was controlled at 0.45 m / s to complete the oxidation stage.

[0031] (3) Drying stage: Maintain the temperature at 80±1℃, reduce the relative humidity to 7%, run for 15 hours with a circulating air volume of 8 m / s, gradually reduce the drying temperature to 40±1℃ and run for another hour, and restore the plate to normal temperature to complete the negative plate curing and drying process.

[0032] Example 2 1. Positive electrode plate curing: (1) High humidity stage: The 6-DZF-23 positive electrode plate prepared by coating is placed in the curing chamber, and the temperature is maintained at 70℃ and the relative humidity is 99±1%, without turning on the circulating air; Maintain a relative humidity of 99±1% and a pressure of 0.3 MPa for 3 hours; then maintain this pressure and reduce the temperature to 65℃ within 12 hours, while controlling the wind speed at 0.3 m / s. After completion, proceed to the oxidation stage.

[0033] (2) Oxidation stage: Set a small cycle frequency, with the positive pressure stage, negative pressure stage and internal air circulation performed in sequence as a small cycle. There is also a static stage between the positive pressure stage and the negative pressure stage. The time of the positive pressure stage is 3 min, the time of the static stage is 1 min, the time of the negative pressure stage is 2 min, and the time of the internal air circulation is 4 min. The curing chamber temperature was reduced to 60℃ and maintained within 2 hours, the relative humidity was reduced to 27%, the positive pressure was 0.3 MPa, and the negative pressure was -0.3 MPa. Multiple small cycles were iteratively executed for a total of 15 hours, while the internal circulation wind speed was controlled at 0.6 m / s to complete the oxidation stage.

[0034] (3) Drying stage: Maintain the temperature at 80±1℃, reduce the relative humidity to 10%, run for 16 hours with a circulating air volume of 9 m / s, gradually reduce the drying temperature to 40±1℃ and run for another hour, and restore the plate to normal temperature to complete the positive plate curing and drying process.

[0035] 2. Negative electrode plate curing: (1) High humidity stage: The 6-DZF-23 negative electrode plate prepared by coating is placed in the curing chamber, and the temperature is maintained at 60℃ and the relative humidity is 99±1%, without turning on the circulating air; Maintain a relative humidity of 99±1% and a pressure of 0.3 MPa for 3 hours; then maintain this pressure and reduce the temperature to 60℃ within 12 hours, while controlling the wind speed at 0.3 m / s. After completion, proceed to the oxidation stage.

[0036] (2) Oxidation stage: Set a small cycle frequency, with the positive pressure stage, negative pressure stage and internal air circulation performed in sequence as a small cycle. There is also a static stage between the positive pressure stage and the negative pressure stage. The time of the positive pressure stage is 3 min, the time of the static stage is 1 min, the time of the negative pressure stage is 2 min, and the time of the internal air circulation is 4 min. The curing chamber temperature was reduced to 50°C within 2 hours and maintained, the relative humidity was reduced to 27%, the positive pressure was 0.3 MPa, and the negative pressure was -0.3 MPa. Multiple small cycles were iteratively executed for a total of 15 hours, while the internal circulation wind speed was controlled at 0.5 m / s to complete the oxidation stage.

[0037] (3) Drying stage: Maintain the temperature at 80±1℃, reduce the relative humidity to 10%, run for 16 hours with a circulating air volume of 9 m / s, gradually reduce the drying temperature to 40±1℃ and run for another hour, and restore the plate to normal temperature to complete the negative plate curing and drying process.

[0038] Example 3 1. Positive electrode plate curing: (1) High humidity stage: The 6-DZF-21 positive electrode plate prepared by coating is placed in the curing chamber, and the temperature is kept at 65℃ and the relative humidity is 99±1%, without turning on the circulating air; Maintain a relative humidity of 99±1% and a pressure of 0.2 MPa for 3 hours; then maintain this pressure and reduce the temperature to 60℃ within 12 hours, while controlling the wind speed at 0.1 m / s. After completion, proceed to the oxidation stage.

[0039] (2) Oxidation stage: Set a small cycle frequency, with the positive pressure stage, negative pressure stage and internal air circulation performed in sequence as a small cycle. There is also a static stage between the positive pressure stage and the negative pressure stage. The time of the positive pressure stage is 4 min, the time of the static stage is 1 min, the time of the negative pressure stage is 3 min, and the time of the internal air circulation is 3 min. The curing chamber temperature was reduced to 55°C and maintained within 2 hours, the relative humidity was reduced to 30%, the positive pressure was 0.32 MPa, and the negative pressure was -0.32 MPa. Multiple small cycles were iteratively executed for a total of 15.5 hours, while the internal circulation wind speed was controlled at 0.3 m / s to complete the oxidation stage.

[0040] (3) Drying stage: Maintain the temperature at 80±1℃, reduce the relative humidity to 5%, run for 14 hours with a circulating air volume of 7 m / s, gradually reduce the drying temperature to 40±1℃ and run for another hour, and restore the plate to normal temperature to complete the positive plate curing and drying process.

[0041] 2. Negative electrode plate curing: (1) High humidity stage: The 6-DZF-21 negative electrode plate prepared by coating is placed in the curing chamber, and the temperature is maintained at 60℃ and the relative humidity is 99±1%, without turning on the circulating air; Maintain a relative humidity of 99±1% and a pressure of 0.2 MPa for 3 hours; then maintain this pressure and reduce the temperature to 55℃ within 12 hours, while controlling the wind speed at 0.1 m / s. After completion, proceed to the oxidation stage.

[0042] (2) Oxidation stage: Set a small cycle frequency, with the positive pressure stage, negative pressure stage and internal air circulation performed in sequence as a small cycle. There is also a static stage between the positive pressure stage and the negative pressure stage. The time of the positive pressure stage is 4 min, the time of the static stage is 1 min, the time of the negative pressure stage is 3 min, and the time of the internal air circulation is 3 min. The curing chamber temperature was reduced to 50℃ and maintained within 2 hours, the relative humidity was reduced from 99±1% to 30%, the positive pressure was 0.32 MPa, the negative pressure was -0.32 MPa, and multiple small cycles were iteratively executed for a total of 15.5 hours. At the same time, the internal circulation wind speed was controlled at 0.3 m / s to complete the oxidation stage.

[0043] (3) Drying stage: Maintain the temperature at 80±1℃, reduce the relative humidity to 5%, run for 14 hours with a circulating air volume of 7 m / s, gradually reduce the drying temperature to 40±1℃ and run for another hour, and restore the plate to normal temperature to complete the negative plate curing and drying process.

[0044] Comparative Example 1 (No positive pressure, negative pressure, and internal air circulation stages) 1. Positive electrode plate curing: (1) First stage: Place the 6-DZF-20 positive electrode plate prepared by coating into the curing chamber, maintain the temperature at 68℃ and the relative humidity at 99±1%, and do not turn on the circulating air; Maintain a relative humidity of 99±1% for 3 hours; then maintain this pressure and gradually reduce the temperature to 61℃ over 12 hours, while controlling the wind speed at 0.2 m / s. After completion, proceed to the second stage.

[0045] (2) Second stage: Reduce the curing chamber temperature to 57.5°C within 2 hours and maintain it, and reduce the relative humidity to 25% within 16 hours by circulating air and dehumidifying.

[0046] (3) Third stage: Maintain the temperature at 80±1℃, reduce the relative humidity to 7%, run for 15 hours with a circulating air volume of 8 m / s, gradually reduce the drying temperature to 40±1℃ and run for another hour, and restore the plate to normal temperature to complete the positive plate curing and drying process.

[0047] 2. Negative electrode plate curing: (1) First stage: Place the 6-DZF-20 negative electrode plate prepared by coating into the curing chamber, maintain the temperature at 62℃ and the relative humidity at 99±1%, and do not turn on the circulating air; Maintain a relative humidity of 99±1% for 3 hours; then maintain this pressure and gradually reduce the temperature to 57℃ over 12 hours, while controlling the wind speed at 0.2 m / s. After completion, proceed to the second stage.

[0048] (2) Second stage: Reduce the curing chamber temperature to 52.5°C within 2 hours and maintain it, and reduce the relative humidity to 25% within 16 hours by circulating air and dehumidifying.

[0049] (3) Third stage: Maintain the temperature at 80±1℃, reduce the relative humidity to 7%, run for 15 hours with a circulating air volume of 8 m / s, gradually reduce the drying temperature to 40±1℃ and run for another hour, and restore the plate to normal temperature to complete the negative plate curing and drying process.

[0050] Comparative Example 2 (Windless Internal Circulation Phase) 1. Positive electrode plate curing: (1) First stage: Place the 6-DZF-23 positive electrode plate prepared by coating into the curing chamber, maintain the temperature at 70℃ and the relative humidity at 99±1%, and do not turn on the circulating air; Maintain a relative humidity of 99±1% for 3 hours at a pressure of 0.3 MPa; then maintain this pressure and reduce the temperature to 65℃ within 12 hours, while controlling the wind speed at 0.3 m / s. After completion, proceed to the second stage.

[0051] (2) Second stage: Set a small cycle frequency, with the positive pressure stage and the negative pressure stage performed in sequence as a small cycle. There is also a resting stage between the positive pressure stage and the negative pressure stage. The time of the positive pressure stage is 3 min, the time of the resting stage is 1 min, and the time of the negative pressure stage is 2 min. The curing chamber temperature was reduced to 60°C within 2 hours and maintained, the relative humidity was reduced to 27%, the positive pressure was 0.3 MPa, and the negative pressure was -0.3 MPa. Multiple small cycles were iterated and run for a total of 15 hours to complete the second stage.

[0052] (3) Third stage: Maintain the temperature at 80±1℃, reduce the relative humidity to 10%, run for 16 hours with a circulating air volume of 9 m / s, gradually reduce the drying temperature to 40±1℃ and run for another hour, and restore the plate to normal temperature to complete the positive plate curing and drying process.

[0053] 2. Negative electrode plate curing: (1) First stage: Place the 6-DZF-23 negative electrode plate prepared by coating into the curing chamber, maintain the temperature at 60℃ and the relative humidity at 99±1%, and do not turn on the circulating air; Maintain a relative humidity of 99±1% for 3 hours at a pressure of 0.3 MPa; then maintain this pressure and reduce the temperature to 60℃ within 12 hours, while controlling the wind speed at 0.3 m / s. After completion, proceed to the second stage.

[0054] (2) Second stage: Set a small cycle frequency, with the positive pressure stage and the negative pressure stage performed in sequence as a small cycle. There is also a resting stage between the positive pressure stage and the negative pressure stage. The time of the positive pressure stage is 3 min, the time of the resting stage is 1 min, and the time of the negative pressure stage is 2 min. The curing chamber temperature was reduced to 50°C within 2 hours and maintained, the relative humidity was reduced to 27%, the positive pressure was 0.3 MPa, and the negative pressure was -0.3 MPa. Multiple small cycles were iterated and run for a total of 15 hours to complete the second stage.

[0055] (3) Third stage: Maintain the temperature at 80±1℃, reduce the relative humidity to 10%, run for 16 hours with a circulating air volume of 9 m / s, gradually reduce the drying temperature to 40±1℃ and run for another hour, and restore the plate to normal temperature to complete the negative plate curing and drying process.

[0056] Comparative Example 3 (Windless Internal Circulation Phase) 1. Positive electrode plate curing: (1) First stage: Place the 6-DZF-21 positive electrode plate prepared by coating into the curing chamber, maintain the temperature at 65℃ and the relative humidity at 99±1%, and do not turn on the circulating air; Maintain a relative humidity of 99±1% for 3 hours at a pressure of 0.2 MPa; then maintain this pressure and reduce the temperature to 60℃ within 12 hours, while controlling the wind speed at 0.1 m / s. After completion, proceed to the second stage.

[0057] (2) Second stage: Set a small cycle frequency, with the positive pressure stage and the negative pressure stage performed in sequence as a small cycle. There is also a resting stage between the positive pressure stage and the negative pressure stage. The time of the positive pressure stage is 4 min, the time of the resting stage is 1 min, and the time of the negative pressure stage is 3 min. The curing chamber temperature was reduced to 55°C and maintained within 2 hours, the relative humidity was reduced to 85%, the positive pressure was 0.32 MPa, and the negative pressure was -0.32 MPa. Multiple small cycles were executed iteratively for a total of 15.5 hours until the relative humidity was reduced to 25%, thus completing the second stage.

[0058] (3) Third stage: Maintain the temperature at 80±1℃, reduce the relative humidity to 5%, run for 14 hours with a circulating air volume of 7 m / s, gradually reduce the drying temperature to 40±1℃ and run for another hour, and restore the plate to normal temperature to complete the positive plate curing and drying process.

[0059] 2. Negative electrode plate curing: (1) First stage: Place the 6-DZF-21 negative electrode plate prepared by coating into the curing chamber, maintain the temperature at 60℃ and the relative humidity at 99±1%, and do not turn on the circulating air; Maintain a relative humidity of 99±1% and a pressure of 0.2 MPa for 3 hours; then maintain this pressure and reduce the temperature to 55℃ within 12 hours, while controlling the wind speed at 0.1 m / s. After completion, proceed to the oxidation stage.

[0060] (2) Second stage: Set a small cycle frequency, with the positive pressure stage and the negative pressure stage performed in sequence as a small cycle. There is also a resting stage between the positive pressure stage and the negative pressure stage. The time of the positive pressure stage is 4 min, the time of the resting stage is 1 min, and the time of the negative pressure stage is 3 min. The curing chamber temperature was reduced to 50℃ and maintained within 2 hours, the relative humidity was reduced from 99±1% to 80%, the positive pressure was 0.32 MPa, and the negative pressure was -0.32 MPa. Multiple small cycles were executed iteratively for a total of 15.5 hours, reducing the relative humidity to 25%, thus completing the second stage.

[0061] (3) Third stage: Maintain the temperature at 80±1℃, reduce the relative humidity to 5%, run for 14 hours with a circulating air volume of 7 m / s, gradually reduce the drying temperature to 40±1℃ and run for another hour, and restore the plate to normal temperature to complete the negative plate curing and drying process.

[0062] Comparative Example 4 (Positive and Negative Pressure Process with Circulating Air) 1. Positive electrode plate curing: (1) First stage: Place the 6-DZF-20 positive electrode plate prepared by coating into the curing chamber, maintain the temperature at 68℃ and the relative humidity at 99±1%, and do not turn on the circulating air; Maintain a relative humidity of 99±1% and a pressure of 0.25 MPa for 3 hours; then maintain this pressure and reduce the temperature to 61℃ within 12 hours, while controlling the wind speed at 0.2 m / s. After completion, proceed to the second stage.

[0063] (2) Second stage: Set a small cycle frequency, with the positive pressure stage and the negative pressure stage proceeding in sequence as a small cycle. There is also a static stage between the positive pressure stage and the negative pressure stage. The time of the positive pressure stage is 3.5 min, the time of the static stage is 1 min, and the time of the negative pressure stage is 2.5 min. The wind speed during the positive and negative pressure process is 0.45 m / s. The positive and negative pressure stages are continuously supplied with air. The curing chamber temperature was reduced to 57.5℃ and maintained within 2 hours, the relative humidity was reduced to 25%, the positive pressure was 0.25 MPa, and the negative pressure was -0.25 MPa. Multiple small cycles were iterated and run for a total of 16 hours to complete the second stage.

[0064] (3) Third stage: Maintain the temperature at 80±1℃, reduce the relative humidity to 7%, run for 15 hours with a circulating air volume of 8 m / s, gradually reduce the drying temperature to 40±1℃ and run for another hour, and restore the plate to normal temperature to complete the positive plate curing and drying process.

[0065] 2. Negative electrode plate curing: (1) First stage: Place the 6-DZF-20 negative electrode plate prepared by coating into the curing chamber, maintain the temperature at 62℃ and the relative humidity at 99±1%, and do not turn on the circulating air; Maintain a relative humidity of 99±1% for 3 hours at a pressure of 0.25 MPa; then maintain this pressure and reduce the temperature to 57℃ within 12 hours, while controlling the wind speed at 0.2 m / s. After completion, proceed to the second stage.

[0066] (2) Second stage: Set a small cycle frequency, with the positive pressure stage and the negative pressure stage proceeding in sequence as a small cycle. There is also a static stage between the positive pressure stage and the negative pressure stage. The time of the positive pressure stage is 3.5 min, the time of the static stage is 1 min, and the time of the negative pressure stage is 2.5 min. The wind speed during the positive and negative pressure process is 0.45 m / s. The positive and negative pressure stages are continuously supplied with air. The curing chamber temperature was reduced to 52.5℃ and maintained within 2 hours, the relative humidity was reduced to 25%, the positive pressure was 0.25 MPa, and the negative pressure was -0.25 MPa. Multiple small cycles were iterated and run for a total of 16 hours to complete the second stage.

[0067] (3) Third stage: Maintain the temperature at 80±1℃, reduce the relative humidity to 7%, run for 15 hours with a circulating air volume of 8 m / s, gradually reduce the drying temperature to 40±1℃ and run for another hour, and restore the plate to normal temperature to complete the negative plate curing and drying process.

[0068] Five electrodes were randomly selected from five positions (upper left, lower left, upper right, lower right, and center) of the curing chamber according to their positive and negative models, based on Examples 1-3 and Comparative Examples 1-4. The free lead content of the electrodes was tested, and the data are shown in Table 1.

[0069] Table 1

[0070] The positive and negative plates prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were paired and assembled. After charging, 2000 of each battery were counted to determine the pass rate of discharge during the charging process (based on the discharge of 18 batteries in series to the termination voltage of 183 V, the voltage of each individual battery was recorded at this point, and those below 9.9 V and above 10.85 V were judged as unqualified, and the pass rate was calculated). The data are shown in Table 2.

[0071] Table 2

[0072] The data in Tables 1 and 2 illustrate that the free lead content in the electrode paste prepared using this method is 3.16% lower on average than that of the comparative sample, and the curing is more uniform. After assembly and charging, the battery discharge qualification rate is 3.17% higher on average than that of the comparative sample. This demonstrates that the iterative sequence of "positive pressure oxygen retention → normal pressure buffering → negative pressure dehydration → internal air circulation for temperature and humidity equalization" designed in this invention directly solves the problem of high local water content and insufficient oxidation of free lead from the root cause, achieving integrated oxidation-dehydration-homogenization and improving electrode consistency.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A process for curing and drying valve-regulated lead-acid battery plates, characterized in that, Includes the following steps: (1) High humidity stage: In the first stage, the plates are kept moist at a temperature of 65±5℃, relative humidity of 98±2%, and pressure of 0.2~0.3 MPa without turning on the circulating air; In the second stage, the plates that have been moisturized in the first stage are kept moist at a temperature of 60±5℃ and a relative humidity of 90±2%, while the circulating air is turned on simultaneously. (2) Oxidation stage: The positive pressure stage, static stage, negative pressure stage and internal air circulation are performed in sequence as a cycle, and multiple cycles are executed iteratively to achieve oxidation of the plate after high humidity treatment; wherein, the positive pressure is 0.2~0.3 MPa, the negative pressure is -0.3~-0.2 MPa, and the air velocity of the internal air circulation is 0.3~0.6 m / s; (3) Drying stage: Dry the oxidized plates.

2. The valve-regulated lead-acid battery plate curing and drying process according to claim 1, characterized in that, In step (1), the circulating wind speed in the second stage is 0.1~0.3 m / s.

3. The valve-regulated lead-acid battery plate curing and drying process according to claim 1, characterized in that, In step (2), the settling time is 1 to 3 minutes.

4. The valve-regulated lead-acid battery plate curing and drying process according to claim 1, characterized in that, Step (2) is executed iteratively for 90-95 cycles.

5. The valve-regulated lead-acid battery plate curing and drying process according to claim 1, characterized in that, The temperature of the oxidation stage in step (2) is 65±5℃ and the relative humidity is 25±5%.

6. The valve-regulated lead-acid battery plate curing and drying process according to claim 1, characterized in that, The drying stage in step (3) consists of two phases. The temperature of the first drying stage is 80±1℃, and the relative humidity is 5%~10%. The temperature for the second drying stage is 40±1℃, and the relative humidity is 5%~10%.

7. The valve-regulated lead-acid battery plate curing and drying process according to claim 6, characterized in that, The circulating air volume in the first drying stage is 7~9 m / s.

8. The valve-regulated lead-acid battery plate curing and drying process according to claim 6, characterized in that, The drying time for the first drying stage is 14-16 hours, and the drying time for the second drying stage is 1-1.5 hours.

9. A valve-regulated lead-acid battery plate prepared by the curing and drying process of a valve-regulated lead-acid battery plate according to any one of claims 1 to 8.

10. The application of the valve-regulated lead-acid battery plate according to claim 9 in the preparation of valve-regulated lead-acid batteries.

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