CN112582585B

CN112582585B - Method for improving connectivity of punched grid and lead plaster and battery prepared by method

Info

Publication number: CN112582585B
Application number: CN202011027089.2A
Authority: CN
Inventors: 刘长来; 夏诗忠; 李建华; 徐建刚; 余国林; 邓国强
Original assignee: Camel Group Xiangyang Storage Battery Co Ltd
Current assignee: Camel Group Xiangyang Storage Battery Co Ltd
Priority date: 2020-09-25
Filing date: 2020-09-25
Publication date: 2023-04-25
Anticipated expiration: 2040-09-25
Also published as: CN112582585A

Abstract

A method for improving the combination property of a punched grid and lead plaster and a prepared battery comprise the following steps: placing the grid into a space with the temperature of 50-80 ℃ and the humidity of 70-98%; oxygen etching of the grid and lead plaster interface: the lead plaster is coated and filled on the grid to form a polar plate, and the polar plate is placed in a space with forced circulation wind and periodically replaced with the circulation wind to perform temperature and humidity step control; and (3) formation and reverse charging: and assembling the polar plates into a battery, adding acid in the formation procedure, reversely charging, and reducing an oxygen corrosion network formed at the interface of the lead plaster and the grid into a conductive lead network. The invention increases the binding force of the lead plaster by carrying out the oxygen etching on the surface of the grid through a chemical and electrochemical method, does not hurt the grid main body, ensures the conductivity during the whole service life of the grid, and ensures that the charges of the active substances rapidly pass through the interface between the grid and the active substances, thereby realizing the use requirement that the battery is suitable for various different climatic environments, different discharge depths and even transitional discharge.

Description

Method for improving connectivity of punched grid and lead plaster and battery prepared by method

Technical Field

The invention relates to a method for improving the combination of a punched grid and lead plaster, and belongs to the technical field of lead-acid storage batteries.

Background

Currently, the number of vehicle-mounted electric appliances of an automobile is increased, and the automation and the comfort are improved increasingly. The trip regions of people are also wider and wider, and the automobile battery is required to be more suitable for various different climatic environments, different discharge depths and even abused and transitional discharge use requirements. At present, the main grid used for the start-up type lead-acid storage battery and the start-stop storage battery mostly adopts an efficient and environment-friendly continuous punching grid process, but the surface of the punching grid is smooth and clean and has poor binding force with lead plaster, thereby affecting the charge and discharge performance of the battery and reducing the performance of the battery.

The basic flow of the production of the lead-acid storage battery is as follows: the molten liquid lead alloy is continuously cast (a molten casting blank) to form a lead blank with a large grain structure, and then the lead blank is subjected to 3-6 times of roller (cold rolling) to form a lead belt, the lead belt is mechanically punched, grains are rolled more densely, the punched grid surface is smooth and clean, the specific surface area of the punched grid is reduced by 50% compared with that of a traditional gravity casting grid, therefore, the binding force between wet plate lead paste prepared by adopting a traditional production process for surface pretreatment and a lead paste coating process and the grid is obviously reduced, the wet plate is solidified and dried to form a green plate, and the green plate is assembled into a non-liquid battery and is acidified to form a wet charge battery. The binding force between the lead plaster and the grid is obviously reduced, so that the conductivity of the battery is affected. The surface state and the crystal grain structure diagram of the traditional gravity casting grid are shown in 1-2, the edges of ribs of the casting grid are uneven, the surface of the casting grid is uneven, and crystal grains are obvious; the grain structure and the surface state of the punching grid are shown in figures 3-4, and the edges of the ribs of the punching grid are neat and smooth; the surface of the punching grid is horizontal and the grains are not obvious.

The patents ZL 2014 2 0461631.9 and ZL 2014 2 0461733.0 provide physical methods for improving the surface roughness of the punched grid, wherein a shaping procedure is added after the punched grid is formed, the equipment is required to be accurately controlled, otherwise, the grid is deformed or the grid grain structure is distorted, and the grid strength is reduced.

Disclosure of Invention

The invention aims to provide a method for improving the combination property of a punched grid and lead plaster, which increases the combination force of the grid and the lead plaster, increases the conductivity of the interface of the grid and the lead plaster, ensures the conductivity of the whole service life of the grid, and ensures that the charges of active substances rapidly pass through the interface of the active substances of the grid, thereby realizing the use requirements of the battery for adapting to various different climatic environments and different discharge depths.

The invention also aims to provide a battery prepared by the method for improving the combination property of the punched grid and the lead plaster.

The technical scheme of the invention comprises the following working procedures of polar plate production and battery formation:

step 1) oxygen etching on the surface of a grid: after the grid is punched, placing the grid into a space with circulating air at the temperature of 50-80 ℃ and the humidity of 70-98% for 4-10 hours, and forming weak oxidation points on the surface of the grid through oxygen etching;

step 2) oxygen etching of the grid and lead plaster interface: the lead plaster is coated on a grid to form a polar plate, the polar plate coated with the lead plaster is placed in a space with forced circulation wind and periodical replacement of the circulation wind, temperature and humidity are controlled stepwise, the temperature of 80-50 ℃ is kept, the humidity of the space is regulated to 98-15% in stages, an oxygen etching network (PbOn) for forming the interface between the lead plaster and the grid is enlarged on the basis of the oxygen etching point of the step 1), and the physical and chemical binding force between the lead plaster and the grid is enhanced; by forming a porous water-soluble interface, the design of an oxygen channel is enhanced, so that the oxygen corrosion of the grid and lead plaster interface is promoted;

and 3) formation and reverse charging: the polar plates in the step 2) are assembled into a battery, after acid is added in the formation procedure, the battery is kept stand for 0.5 to 1 hour, and then reverse charging is carried out for 1 to 4mA/cm2 1 to 2 hours, so that an oxygen corrosion network (PbOn) formed at the interface of the lead plaster and the grid is reduced into a conductive lead (Pb) network, thereby not only increasing the binding force of the grid and the lead plaster, but also increasing the conductivity of the interface of the grid and the lead plaster.

The temperature and humidity stepwise control performed in the step 2) is as follows: the polar plate is stored in a space with circulating air at 50-70 ℃ for 48-72 h, the change of the ambient humidity is 8+/-1% lower, 3+/-1% return, 8+/-1% return and 3+/-1% return, and fresh air with the volume of 20-80 m < 3 >/min is required to be injected into the space every 3-5 min, so that the grid interface oxygen etching reaction is carried out while the basic network structure of the lead plaster is enhanced.

The temperature and humidity stepwise control performed in the step 2) is as follows: the polar plate is stored in the space with circulating air at 50-70 ℃ for 48-72 h, wherein the humidity is 98% -90% -93% -85% -88% -80% -83% -75% -78% -70% -73% -65% -68% -60% -63% -55% -58% -50% -53% -45% -48% -35% -38% -30% -33% -25% -28% -20% -23% -15%. Every 3 to 5 minutes, fresh air needs to be injected into the space.

The step 3) of the invention is reverse charging: after the cells are connected in series in the formation cell, current is introduced from the negative electrode terminal and flows out from the positive electrode terminal.

The invention step 3) is to stand the battery for 0.1 to 0.5 hours after reverse charging, and then turn to enter the formation charging procedure.

In the invention, after the active substance network is completed in the step 2), rich oxygen ions are dissolved in liquid water in a network gap, the environment humidity is designed to be dynamically reduced, so that the moisture in the active substance network gap and the moisture in the environment form a dynamic diffusion and reduction process, namely, the moisture in the active substance network is reduced along with the change of the environment humidity, the process of rising, falling again and rising again, the process is favorable for the diffusion of oxygen into the active substance and the grid interface, the moisture in the active substance gradually diffuses and reduces to the environment, the solubility of oxygen reaches the maximum between 80% and 90%, the grid interface rapidly expands to the whole grid surface on the basis of an oxygen point formed in the step 1), the PbOn grows and is combined with 3BS and 4BS in the active substance to form a complex, and the simple physical combination of the lead plaster and the grid in the initial stage of polar plate coating is broken. The reaction process needs about 20-40 hours until the ambient humidity is reduced to 15%, the moisture in the lead plaster and the ambient humidity reach balance, and the catalysis of the water on the surface of the plate grid by oxygen corrosion disappears.

In the invention, a reverse formation process is executed in the initial stage of battery formation in the step 3), and the active substances on the polar plates and the grids are subjected to electrochemical linking. In the step 2), the oxide layer PbOn formed on the surface of the lead plaster and the grid increases the bonding strength of the lead plaster and the grid, but the conductivity of the PbOn is poor, which affects the charge and discharge performance of the storage battery. In the step of chemical acid addition and reverse charging, the positive electrode of the storage battery is subjected to a reduction reaction, the reaction firstly occurs from the interface of the grid and the lead plaster, and semiconductive PbOn is reduced into metallic lead, because the PbOn is a bonding network between the grid and the interface of the active substance, the reduced metallic lead is different from the grain structure in the grid, and continuously bears the bonding network function between the grid and the interface of the active substance and has excellent conductivity.

The invention is realized by three steps: forming a preliminary oxygen etching point (PbOn) on the surface of a grid by carrying out grid pretreatment before lead plaster coating; after the lead plaster is coated and filled into the punching grid, controlling the curing and drying process of the lead plaster, expanding an oxygen etching network (PbOn) for forming the interface of the lead plaster and the grid on the basis of the preliminary oxygen etching point, and enhancing the physical and chemical binding force between the lead plaster and the grid; in the formation process, an oxygen corrosion network (PbOn) formed at the interface of the lead plaster and the lead plaster is reduced into a conductive lead (Pb) network through a reverse charging process, so that the binding force of the lead plaster and the lead plaster is increased, and the conductivity of the interface of the lead plaster and the lead plaster is also increased. The three steps are the indistinct parts of the invention, and the use requirements of the battery for adapting to various charge and discharge deep cycles, tolerating abuse and being discharged in a transitional way are finally improved.

The battery produced by the process of the invention has obviously improved high and low temperature performance, and takes an AGM70Ah battery as an example, according to the test of BMS 95001-4 standard, the 50% deep cycle life can be improved from 300 times to 500 times, the MHT shallow cycle life can be improved from 8000 times to 12000 times, and the 17.5% life can be improved from 18 units to 30 times.

In the production and battery formation processes of the polar plate of the storage battery, the invention performs oxygen etching on the surface of the grid to increase the binding force of lead plaster, and simultaneously does not hurt the grid main body, thereby ensuring the conductivity of the grid during the whole service life, ensuring that the charges of active substances rapidly pass through the interface between the grid and the active substances, thereby realizing the use requirements of the battery for adapting to various different climatic environments, adapting to various different discharge depths, and even being abused and transited to discharge.

Drawings

FIG. 1 is a surface state diagram of a prior art gravity cast grid;

FIG. 2 is a grain structure diagram of a prior art gravity cast grid;

FIG. 3 is a surface state diagram of a punched grid;

FIG. 4 is a grain structure diagram of a punched grid;

FIG. 5 is one of the surface views of the punched grid of the present invention after step 1);

FIG. 6 is a view of the green sheet grid surface of the punched grid of the present invention after removal of the lead paste;

fig. 7 is a diagram of the formation of a bond network at the grid and lead paste interface after the plate paste of the present invention is applied.

Detailed Description

In the drawings, fig. 1 shows the surface state of a prior art gravity casting grid.

Fig. 2 shows the grain structure of a prior art gravity cast grid.

Fig. 3 is a surface state of a punched grid.

Fig. 4 is a grain structure of a punched grid.

Fig. 5 shows the surface state of the punched grid of the present invention after step 1), the initial oxygen etch point of the punched grid.

Fig. 6 shows the green plate grid surface after removal of the lead paste according to the present invention.

Fig. 7 shows the formation of a bond network at the grid and lead paste interface after the plate paste of the present invention: and combining the lead plaster of the finished wet-charged battery with the grid to form a sectional view.

The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention and the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments, and all other embodiments obtained by those skilled in the art without making any inventive effort based on the embodiments of the present invention are within the scope of protection of the present invention.

Example 1

Firstly, after grid punching is completed, placing the grid into a space with circulating air at the temperature of 75 ℃ and the humidity of 98% for 2 hours. As shown in fig. 5, preliminary oxygen etching spots were formed on the surface of the smooth punched grid.

In the second step, the second step is carried out,

a. and (3) placing the pole plate coated with the lead paste into a space with circulating air at the temperature of 75 ℃ and the humidity of 98% for 4 hours.

b. Setting multi-stage humidity control and polar plate drying:

after the polar plate is solidified and dried, the lead plaster is removed, and the microscopic result of the surface of the grid is observed, as shown in fig. 6.

Third step

After the batteries are assembled and acid is added, the batteries are connected in series into a circuit. The power is supplied according to the following process:

step (a)	System and method	Time h	Current mA/cm2
				1	Adding acid and standing	1	0
2	Reverse charging	1	3
				3	Standing steering	0.4	0
4	Formation charging	Enter the prior art formation charging stage	……

And (5) dissecting the finished wet-charged battery, taking out the polar plate, and observing the sectional states of the lead plaster and the polar plate, wherein the sectional states of the polar plate are shown in fig. 7. Lead plaster is already organically combined with the surface of the grid.

Example 2

Firstly, after grid punching is completed, placing the grid into a space with circulating air at the temperature of 70 ℃ and the humidity of 95% for 3 hours.

In the second step, the second step is carried out,

c. and (3) placing the pole plate coated with the lead paste into a space with circulating air at the temperature of 50 ℃ and the humidity of 98% for 4 hours.

d. Setting multi-stage humidity control and polar plate drying:

third step

example 3

Firstly, after grid punching is completed, placing the grid into a space with circulating air at 50 ℃ and humidity of 95% for 4 hours.

In the second step, the second step is carried out,

e. and (3) placing the pole plate coated with the lead paste into a space with circulating air at the temperature of 60 ℃ and the humidity of 98% for 4 hours.

f. Setting multi-stage humidity control and polar plate drying:

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third step

step (a)	System and method	Time h	Current mA/cm2
				1	Adding acid and standing	1	0
2	Reverse charging	2	2
				3	Standing steering	0.2	0
4	Formation charging	Enter the prior art formation charging stage	……

Experimental analysis:

the lead-acid storage battery processed in the embodiment 1, the embodiment 2 and the embodiment 3 has better charge and discharge performance, longer service life of different depth of discharge and better repeated overdischarge service life (abused and overdischarged).

In examples 1, 2 and 3, the grid pretreatment was performed before the lead paste was applied, and the temperatures of 75℃and 98% humidity, 70℃and 95% humidity, and 50℃and 95% humidity were used in example 1 and 2, respectively; after the lead plaster is coated and filled into the punching grid, the temperature of the lead plaster is controlled to be 50-80 ℃ and the humidity of the lead plaster is controlled to be gradually reduced from 98% to 15%; and a formation procedure, wherein the reverse charging process is adopted for example 1 (3 mA/cm < 2 >) for one hour, example 2 (2 mA/cm < 2 >) for one hour and example 3 (2 mA/cm < 2 >) for two hours, and the electrochemical combination action of three stages forms a good physical and chemical combined lead (Pb) network at the interface between the lead plaster and the lead plaster, so that the bonding force between the lead plaster and the lead plaster is increased, and the conductivity between the lead plaster and the lead plaster interface is increased.

The three examples show a significant increase in battery life, with the maximum increase in deep discharge life (50% life) for example 3 and the maximum increase in low shallow cycle life for example 1.

Claims

1. A method for improving the combination of a punched grid and lead plaster, which is characterized in that: the invention is realized by three steps: pre-treating the grid before the lead plaster is coated and filled to form a preliminary oxygen etching point on the surface of the grid; after the lead plaster is coated and filled into the punching grid, controlling the curing and drying process of the lead plaster, expanding an oxygen etching network forming the interface of the lead plaster and the grid on the basis of the preliminary oxygen etching point, and enhancing the physical and chemical binding force between the lead plaster and the grid; in the formation procedure, an oxygen etching network formed at the interface of the lead plaster and the grid is reduced into a conductive lead network through a reverse charging process, so that the binding force of the grid and the lead plaster is increased, and the conductivity of the interface of the grid and the lead plaster is also increased; the method specifically comprises the following steps:

step 1) oxygen etching on the surface of a grid: after the grid is punched, placing the grid into a space with circulating air at the temperature of 50-80 ℃ and the relative humidity of 70-98% for 4-10 hours, and forming oxidation points on the surface of the grid through oxygen etching;

step 2) oxygen etching of the grid and lead plaster interface: the lead plaster is coated on a grid to form a polar plate, the polar plate coated with the lead plaster is placed in a space with forced circulation wind and periodical replacement of the circulation wind, temperature and humidity are controlled stepwise, the temperature of 80-50 ℃ is kept, the humidity of the space is regulated to 98-15% in stages, an oxygen etching network of an interface between the lead plaster and the grid is formed on the basis of oxygen etching points of the step 1), and physical and chemical binding force between the lead plaster and the grid is enhanced;

step 2) performing temperature and humidity stepwise control as follows: the polar plate is continuously stored in a space with circulating air at 50-70 ℃ for 48-72 h, the change of the ambient humidity is 8+/-1 percent of decrease, 3+/-1 percent of return, 8+/-1 percent of return, and 3+/-1 percent of return, and fresh air of 20-80 m < 3 >/min is required to be injected into the space every 3-5 min, so that the grid interface oxygen etching reaction is carried out while the basic network structure of the lead plaster is enhanced; in the period that the humidity is higher than 45%, the change of the ambient humidity is 8+/-1% lower, the temperature is kept for 0.5 hour, the temperature is raised for 3+/-1% lower, the temperature is kept for 3-8 hours, the temperature is lowered for 8+/-1% lower, the temperature is kept for 0.5 hour, the temperature is raised for 3+/-1% lower, and the temperature is kept for 3-8 hours;

and 3) formation and reverse charging: assembling the polar plates in the step 2) into a battery, adding acid in the formation process, standing for 0.5-1 h, and then feeding 1-4 mA/cm ² And (3) reversely charging for 1-2 hours, and reducing an oxygen corrosion network formed at the interface of the lead plaster and the grid into a conductive lead network.

2. The method for improving the combination property of a punched grid and lead plaster according to claim 1, wherein the temperature and humidity step control performed in the step 2) is as follows: the plate continues to store 48-72 h in the space with circulating air at 50-70 ℃, wherein the humidity is 98% -90% -93% -85% -88% -80% -83% -75% -78% -70% -73% -65% -68% -60% -63% -55% -58% -50% -53% -45% -48% -35% -38% -30% -33% -25% -28% -20% -23% -15%. Every 3-5 minutes, fresh air needs to be injected into the space.

3. The method for improving the connectivity of a punched grid with a lead plaster according to claim 1, wherein step 3) of reverse charging is: after the cells are connected in series in the formation cell, current is introduced from the negative electrode terminal and flows out from the positive electrode terminal.

4. The method for improving the bonding property of a punched grid and lead plaster according to claim 1, wherein the step 3) is characterized in that after reverse charging, the battery is kept stand for 0.1-0.5 hour and then is turned to enter a formation charging process.

5. A battery made by the method of improving the connectivity of a punched grid with a lead plaster of any one of claims 1-4.