WO2001020699A1

WO2001020699A1 - A method of producing a lead-base plate for a storage battery

Info

Publication number: WO2001020699A1
Application number: PCT/CN1999/000146
Authority: WO
Inventors: Yuerong Liu; Yuesheng Feng; Yifeng Feng; Rong Sun
Original assignee: Yuerong Liu; Yuesheng Feng; Yifeng Feng; Rong Sun
Priority date: 1999-09-13
Filing date: 1999-09-13
Publication date: 2001-03-22
Also published as: AU5725799A

Abstract

The invention relates to a storage-battery plate, and more particularly, to a method of producing a lead-base plate for a storage battery. The method includes three main steps: hot-casting a plate grid into final shape, coating and solidifying active materials on the plate grid, and forming the solidified electrode plate. The method is characterized by that cold extrusion is applied to the plate grid after hot-casting the plate grid into final shape, or a hydrated silicate is added into the active materials to be coated and solidified on the plate grid, or forming the electrode plate with the active materials solidified by charge method using cyclic pulse current. The resultant plate has prolonged use life, enhanced electric conductivity, and increased specific energy of the storage battery, large current discharge capacity and low-temperature discharge characteristic, at the same time eliminating environment pollution during producting the storage-battery plate.

Description

Method for manufacturing lead base electrode plate of battery

The invention belongs to the field of battery electrode plates, and particularly relates to a method for manufacturing a lead plate for a battery.

Background technique

At present, the battery we have seen is manufactured by a more mature traditional process, and its electrode plate process includes grid formation, filling and curing of active materials (lead paste), and formation of three main processes. The shaped grid is called the electrode plate after being filled with the solidified lead paste, and the electrode plate is called the cooked electrode plate after being processed (formed) by the electrification process.

In storage batteries, the active materials lead and lead dioxide that participate in the battery flow reaction are loose porous bodies that need to be fixed on a carrier, which is called a grid or lattice (framework). The role of the grid is to support activity The material also transmits current, and the grid with good conductivity and reasonable structure can make the current be evenly distributed on the active material along the ribs, thereby improving the utilization rate of the active material.

The grid is usually made of a lead-based alloy, and there are also pure lead or lead-plated copper mesh (for the negative electrode). The molding process usually uses casting, and a few use the method of drawing a mesh. Lead-based alloys are mainly lead, usually accounting for about 95% or more. The metals added are antimony, arsenic, cadmium, tin, calcium, silver, aluminum, strontium, etc., or combinations thereof.

Lead-based alloy grids formed by the hot casting method may not only form characteristic solid solution bodies, but also may form mesophases with different crystal structures, most of which are compounds between metals or between metals and metalloids. Studies have shown that this compound is dominated by metal bonds and often does not follow the valence law, which has an effect on the conduction capacity of the alloy. Since the industrial control conditions of the hot-cast lead substrate grid are not absolutely the same, even if the grids manufactured by the same hot-casting machine have the same number of internal bubbles and alloy lattices, there are certain differences. There have been many literature reports on the aging hardening of metal dissolution for a long time. The lead-based alloy grid is also only improved from the shape of the grid, such as GB2127614, April 11, 1984, by Sonnenschein A company application discloses an electrode grid having a honeycomb structure, and the shape of the electrode grid is substantially similar to an oblique quadrangle or a regular hexagon.

The electrode plate of a lead storage battery is made of lead paste filled on a grid. The formula of the lead paste, the method of the paste, and the curing conditions have an important effect on the phase composition of the electrode plate. In recent decades, various countries have matured and mastered the formulation and curing conditions of lead paste, and have seen it in a large number of literature reports, such as EP0348702, which was applied by Sonnenschein Company on January 3, 1990. A method for coating an electrode grid. The grid is made of lead and is performed by dipping a solution of a coating material.

The energization process of the electrode plates is called formation, and the electrode plates are called cooked plates after being formed. In the traditional battery production process, the electrolytic plate is usually formed by using an electrolytic cell. After the formation, the electrode is washed and dried. Dry, and then battery assembly. Because the chemical conversion tank uses dilute sulfuric acid as the electrolyte, acid mist and environmental pollution generated during the chemical conversion process have always been difficult problems for the battery industry.

In recent years, some manufacturers in various countries have begun to use a battery or battery pack formation method. That is, the electrode plate is first assembled into a battery or battery pack, and the electrolyte is added to form the battery. This method can effectively improve the assembly efficiency and suppress the generation of acid mist. But matter into a cell or battery using the acid injection method or a two injection acid method, the pastel is necessary to add Pb ₃ 04, studies suggest that the above-mentioned chemical conversion methods are employed there is a long charging time, a large power loss, pollution of the environment Disadvantages such as public pollution caused by traditional electrolytic cell formation methods have always been the focus of governance of the battery industry.

Disclosure of invention

The purpose of the present invention is to provide a method for manufacturing a lead plate for a storage battery, that is, to utilize the inherent characteristics of the metal, change the formula of the lead paste and the formation of the electrode plate, so as to prolong the service life of the manufactured plate and enhance the conductivity. And the battery can reduce environmental pollution.

The manufacturing method of the present invention includes three main steps: hot-casting grids, filling and curing active materials on the grids, and transforming the electrode plates with the cured active materials, which are characterized by: Cold extrusion is applied to the rear grid; or hydrated silicate is added to the grid to fill and solidify the active material and paste formulation; or pulsed current is used to form the solidified electrode plate.

Any two or three of the above three methods can be used in combination. The cold extrusion applied to the grid is applied pressure from the outside to the inside, and the pressure is 100-800Kg / _C m ^{2. The} cold extrusion may be applied to the grid more than once. The hydrated silicate added to the lead paste formula can be added to the positive lead paste, or to the negative lead paste, or to both the positive and negative lead paste formulations. The hydrated silicate is montmorillonite, wherein montmorillonite composite molecular structure _{_{(Na, Ca) 0. 33}} (AL, Mg) 2 (Si 4 O 10) (ΟΗ) 2 · ηΗ 2 0, η = positive integer. The proportion of hydrated silicate added to the lead paste formula is 0.1 to 3% by weight in the lead paste formula. The hydrated silicate added in the lead paste formulation is subjected to an industrial acid dipping treatment in advance. The electrode plate formation can be performed either before the battery or battery pack is assembled, or after the green plate is assembled into a battery or a battery pack. After the green board is assembled into a battery or a battery pack, it is charged and formed, and its lead paste formulation does not need to be added with Pb ₃ 0 ₄ . The pulsating current used in the formation is a periodic pulsating current, and the frequency is an arbitrary value. The waveform of the current is a square wave, a sawtooth wave, a negative pulse wave, a sine half wave, a full sine wave, or any combination thereof. The current intensity of the pulsating current is greater than 0.2C, and the average charging voltage is 1-2 times the rated voltage of the battery or battery pack.

Because there are many micropores on the surface of the lead substrate grid manufactured by only the hot casting method (the reason for this is caused by the residual and escape of air molecules piled up in the lead-based alloy during the hot casting process), the air bubbles inside can easily cause the plate to conduct Heating, meanwhile, the shape of the metal lattice is irregular and the arrangement and combination are loose, these factors directly affect the conductivity of the grid. The lattice arrangement of lead-based alloys is easily deformed by force. After the hot-cast lead substrate grid is formed, a cold extrusion process is added. That is, a conventional punch (for example, 100-800K _g / cm ² pressure) or a hydraulic press is used to form the lead substrate. Barrier Performing the cold extrusion processing once or more can greatly improve the grid performance, and most of the micropores can be removed. Through cold extrusion, the lead-based alloy crystal lattice undergoes significant lattice set deformation due to external pressure on the grid, which makes the metal lattice arrangement and combination become closer. After the bubbles are discharged during the dissolution process, In the remaining lattice vacancies, the alloy's conduction band capacity is enhanced, and at the same time, the grid's pull force to fill and solidify the active material is enhanced, and the internal resistance becomes smaller when conducting electricity. The cold-extruded grid can be used for both positive and negative electrodes.

At present, the more standard lead battery lead plate lead paste formula is:

1) Formula of positive lead paste: It is made by mixing H ₂ S0 ₄ , H ₂ 0 and Pb powder with proper proportion, and the apparent density is controlled at

4.0 ± 0.1 (g / cm ³ );

2) Negative lead paste formula: On the basis of 1), organic swelling agents such as barium sulfate and humic acid, 0-hydroxy-naphthoic acid, sodium lignosulfonate, acetylene black, and synthetic tanning agent are selected to be added. You can choose one or several kinds to mix according to a certain proportion.

The hydrated silicates according to the present invention are, for example, Montmorillorite, and the weight percentage of the montmorillonite additive in the lead paste formulation is 0.1 to 3%.

According to modern electrochemical theory, the chemical activity of the positive electrode Pb is mainly determined by the hydrogen content, while the hydrogen contained in the positive electrode Pb (¾ exists mainly on the surface of the crystal of Pb in the form of adsorbed water. According to gels with proton and electron transport functions From the perspective of a crystal system, the smallest unit of the structure of the positive electrode active material is PbC ^ particles, not Pb02 crystals. Such Pb (¾ particles are composed of hydrated Pbft-PbO (0H) 2, a few! ^ The particles contact to form a microporous structure Aggregates and aggregate skeletons with macroporous structures. Electrochemical reactions occur on microporous aggregates, which transfer ions and form PbSO on the macroporous aggregates.

Montmorillonite is a hydrated silicate with extremely strong water absorption capacity. After absorbing water, its volume expansion can increase several times to ten times. It has strong adsorption and cation exchange performance. The proper addition of montmorillonite to the positive lead paste can first improve the chemical activity of Pbi ^ due to the water-absorbing dependence of montmorillonite. On the other hand, since PbCfe is converted to PbSO ^ and PbSC ^ is larger than PbOj when the battery is discharged, the volume of the entire positive electrode substance is increased. Therefore, an appropriate amount of montmorillonite is added to the positive lead paste, and its volume expands after absorbing water Physical properties can effectively alleviate the softening and loosening of the active material caused by the volume change during the charge and discharge process, and prolong the service life of the positive electrode plate.

Adding an appropriate amount of montmorillonite to the negative lead paste is mainly used to inhibit the passivation of the negative electrode at different temperatures at low temperatures (below -15 ° C) and high rate discharge (above 1 hour rate), that is, the potential of the negative electrode is obvious. Moving forward, the reaction speed will obviously decrease. It is generally believed that the negative charge capacity of the negative electrode at -4 ° C is only 10% at 25 ° C and the low-temperature discharge capacity is also limited by the negative electrode. The proper addition of montmorillonite in the negative electrode lead paste can greatly improve the negative electrode material. Surface activity, improving the high rate discharge capacity of the anode, especially effectively suppressing the surface area shrinkage of the anode under low temperature conditions, at the same time, it can effectively block hydrogen evolution and lead charge Oxidation during storage after polarization. Therefore, adding an appropriate amount of montmorillonite to the negative electrode lead paste formula can reduce the self-discharge of the negative electrode plate of the battery, especially the low temperature characteristics.

The energization process of the electrode plates is called formation, and the electrode plates are called cooked plates after being formed. The traditional electrochemical theory has fully recognized the charge formation. The electrode materials prepared by chemical methods lack electrochemical activity and are not suitable for use as plates in batteries. Only by electrochemical processing can the chemical activity of the plate materials be fully activated. So that the battery has a useful value of capacity. The method of using the charging method to activate the activity of the plate material is called chemical conversion. According to the viewpoint of the hydrogen (proton) activity model and industrial experiments, Pb prepared by electrochemical methods contains far more hydrogen than that prepared by chemical methods. the content of hydrogen in the form of dependency determines the degree of chemical activity of Pb0 _2.

At present, the formation conditions of the plate grooves of most manufacturers are similar. Table 1 lists the general formation methods of non-dry-charge plate. For dry-charge electrode plates, in order to ensure the first discharge capacity after adding acid, a "two charge and one discharge" formation method is sometimes used. In addition to the electrode plate formation method, there are also a few products that use green plates (unformed electrode plates) to form batteries or battery packs and then charge and form them. The battery or battery pack formation method is divided into two acid injection methods and one The acid injection method, Pb ₃ 04 must be added to the lead paste used to make the electrode plate, and the comparison process and the advantages and disadvantages of the acidification with one and two injections are shown in Table 2. Table 1

The charging current of the above-mentioned existing electrode formation methods adopts continuous DC power (constant current or phased DC). Advantages and disadvantages of the formation process

Acid injection method

Two injections of acid 1. The relative density of the first injection of acid is 1. The formation period is shorter

1.065-1.180 2. Pb ₃ 0 ₄ needs to be added to the lead paste. The battery has

2. High-current charging 24h j, good initial performance of current charging

121g, 36h 3. Require acid pouring equipment

3. Pour out the electrolyte and inject the relative density

1.290-1.40 acid

4. Charge with a small current 61 ^ Final acid concentration

To control at the desired concentration

One injection of acid 1. After estimating the density of the acid to be injected and 1. The lead paste needs to be added with Pb ₃ 0 ₄ , otherwise the amount is generally above 1.200 and the initial capacity is less than the two injections

2. Power on time is at least 72h 2. Long formation time

3. No acid pouring equipment required

Battery manufacturing process of traditional electrolytic cell forming electrode plate:

One grid, one paste, one assembly, one charge, one package

Manufacturing process of battery or battery:

One grid, one paste, one assembly (charging and forming), one package

The method for forming a pulsating current according to the present invention belongs to the formation of a battery or a battery pack. The difference from the existing methods is that:

1) Charging using a pulsating current different from constant voltage or constant current:

2) Lead paste does not need to be added with Pb ₃ 0 ₄ , the formation time does not need to be as long as 36-72 hours, and the battery or battery pack charging time is only 10-18 hours to achieve the purpose of electrode formation and full charge.

Experiments show that when a battery or battery formation method is used, combined with the use of non-constant voltage or non-constant current pulsating current charging, the effect of activating the active material of the electrode plate in a short period of time is better. This formed current is characterized by the use of periodic pulsating current, such as square wave, sawtooth wave, negative pulse wave, sine half wave, sine full wave, etc., as shown in Figure 1-5. The frequency of the pulsating current can be the mains frequency, and it can be formed by one-time charging.

When the plates are formed, the current intensity of the pulsating current is generally greater than 0.2C, but smaller than the withstand capacity of the plates. By changing the current waveform (for example, the sawtooth wave in Figure 2 is changed to reverse sawtooth, the front and back symmetrical sawtooth is centered; or the double sawtooth sawtooth is used, etc.), the pulse depth is changed (for example, the negative pulse depth is changed to 1 / 2 peak, square wave low voltage changed to 1/5 peak, 1/3 peak, etc.), the frequency is taken to be any periodic current (frequency conversion) different from the n multiple of the city power (n = 50), and the charging method is changed to two rushes, one discharge, Three chargers, two amplifiers, etc. To the purpose of charge formation.

The above-mentioned methods of cold-pressing the grid, adding montmorillonite to the formulation of lead paste, or charging the battery or battery pack with a periodic pulsating current can be applied to the plates of lead-acid batteries, as well as The embodiment described above is only a preferred embodiment of the principle of the present invention to a battery plate of a silicon sol (salt) as an electrolyte. The grid can be cold extruded more than once. For example, if the grid is extruded twice (front and back), the montmorillonite is treated by acid dipping before the paste. The montmorillonite is added to the lead paste formula. Prior to the industrial acid (such as sulfuric acid) impregnation treatment, it is beneficial to fully mix with the paste.

The electrode plate manufactured by the cold extrusion method of the present invention increases the bonding strength between the metal lattices and increases the external tensile force. Therefore, in a grid with an appearance structure of equal weight, it can withstand more lead powder adhesion. In other words, with the same amount of lead powder adhered, the grid's ability to resist stress deformation is enhanced. Therefore, after the cold extrusion method is adopted, the amount of lead used can be reduced to achieve the same grid effect, thereby reducing the weight of the battery and increasing the specific energy of the battery.

Studies have shown that the irregular shape of the metal lattice and micropores are one of the sources of high-temperature charging of lead-based batteries. The battery produced by cold extrusion of the grid can withstand greater charging current when other manufacturing methods are the same. , Or the temperature rise is significantly reduced at the same charging current.

In the present invention, by adding montmorillonite to the lead battery lead plate lead paste formula, the utilization rate of active materials can be effectively improved, and the life of the plate and the charging and discharging characteristics can be improved.

The present invention uses a periodic pulsating current formation method to enable the plate material to more effectively activate the chemical activity of the plate material under the action of the pulsating current, while reducing the time required for the plate to form.

BRIEF DESCRIPTION OF THE DRAWINGS

The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

Figure 1. Schematic diagram of square waveform current used for charging;

Figures 2. (a), (b), and (c) are schematic diagrams of the sawtooth wave current used for charging formation;

Figure 3. Schematic diagram of negative pulse waveform current used for charge formation;

Figure 4. Schematic diagram of sine half-wave pulsating current used for charging formation;

Figure 5. Schematic diagram of sinusoidal full-wave pulsating current used for charge formation.

Examples of wooden inventions

Example 1.

The lead substrate grid hot-formed by a conventional method is placed in a grid mold designed for the same, and a 500 Kg / cm ² pressure punch is used to perform a cold extrusion process on the hot-formed lead substrate grid. The paste is transformed into an assembly and a charge, and a 12V100AH battery is finally prepared. Compared with a battery that is not subjected to cold extrusion and other processes, the internal resistance becomes smaller and the charge and discharge capacity is increased.

Example 2. The lead substrate grid hot-formed by a conventional method is placed in a grid mold designed for the same, and a 300 kg / cm ² pressure punch is used to cold-press the front and back sides of the lead substrate grid after hot-casting. After processing, the tensile force of the grid after cold extrusion is significantly increased, so the amount of lead-based materials in each grid can be appropriately reduced, and the paste is transformed into an assembly and charged, and a 4V8AH battery is finally prepared. Compared with batteries that do not reduce the amount of grid lead-based materials, their specific energy is greater. Example 3

Except for a press using a pressure of 10OKg / cm ² , the other steps and effects are the same as in Example 1. Example 4

Except for a press using a pressure of 800 Kg / n ² , the other steps and effects are the same as in Example 1. Example 5

Comparing the battery manufactured in Example 1 with the battery formed by only the hot-casting method using 0.3C constant current charging, it was determined by conventional methods that the temperature of the battery plate of the battery formed by only the hot-cast method quickly increased. To 45-50, or even higher, and the battery plate temperature of the cold extrusion method to treat the grid is only between 37-45'C. Example 6.

100 kg of 80% oxidized lead powder, 0.6 kg of montmorillonite, 8 L of ion-exchanged water, and 12 L of sulfuric acid with a specific gravity of 1.35-1.38, the above raw materials are mixed in accordance with a conventional method to prepare a lead paste, and fill the positive electrode of a lead storage battery. On the grid, the battery prepared by assembling and charging according to conventional methods is used to test and compare the number of charge and discharge cycles. long. Example 7.

150 kg of 80% oxidized lead powder, 0.6 kg of 250 mesh barium sulfate, 0.8 kg of montmorillonite, 6 L of ion-exchanged water, 12 L of sulfuric acid with a specific gravity of 1.30-1.35, and the above raw materials are mixed to prepare a lead paste according to a conventional method, and Filled and coated on the negative electrode grid of lead battery, and converted into a battery prepared by assembling and charging according to conventional methods. Comparing the high temperature current discharge and low temperature discharge experiments at normal temperature can prove that adding montmorillonite to the negative electrode lead paste can be effective. It can improve the utilization rate of the negative electrode active material, suppress the passivation, and make the battery discharge capacity at high current (> 1 hour rate) and low temperature (-5 (TC ~ 0'C)) significantly enhanced.

zExample 8. Before adding the montmorillonite to the lead paste, the battery was first impregnated with industrial sulfuric acid with a specific gravity of 1.25 for 24 hours, and other steps and effects were the same as in Example 7. Example 9.

Charge the assembled battery or battery pack. Use a negative pulse wave with a frequency of 1000 Hz (the negative pulse depth is 80% of the peak voltage), and the peak voltage is 1.5 times the rated voltage. First, charge the battery or battery pack with a negative pulse current of 0.6C for 7-10 hours. Or after the battery pack is completely discharged, continue to charge for 3-5 hours to achieve the purpose of forming the electrode plate and fully charging the battery. Example 10.

Charge the assembled battery or battery pack. Using a sinusoidal full-wave current with a frequency of 50 Hz, the charging current intensity is 0.8C, and the average voltage is 1.3 times the rated voltage. The battery or battery pack is continuously charged for 10 to 18 hours, which can achieve the formation of a battery and a fully charged battery. purpose. Example 11.

Charge the assembled battery or battery pack. The charging current intensity is 1C, the average voltage is 1.35 times the rated voltage, the characteristic waveform is a square wave, and the frequency is modulated to n times (n = 2, 3, 4 ~) the frequency of the mains frequency using a frequency conversion technology. This characteristic charging current is used Continuously charging the battery or battery pack for 10-15 hours can achieve the purpose of forming the electrode plate and fully charging the battery. Example 12.

The lead substrate grid manufactured in Example 1 was filled with the lead paste of Example 6 on the positive grid of a lead-acid battery, and was formed-assembled according to a conventional method. After a charge-discharge index and cycle number comparison test, this method was used to manufacture The resulting lead-acid battery has not only enhanced charge and discharge capabilities, reduced internal resistance, but also extended service life. Example 13.

The lead-based electrode plate manufactured in Example 7 is used to assemble a battery or battery pack, and the battery or battery pack is charged using the charging method of Example 9. The purpose of forming the electrode plate and fully charging the battery can be achieved. The low-temperature discharge experiments were compared. The lead-acid battery produced by the combined method not only enhanced the high-current discharge capacity, reduced the internal resistance, and especially improved the low-temperature discharge performance.

Claims

Gall

A method for manufacturing a lead plate for a storage battery, comprising three main steps: a hot-cast grid, filling and curing an active material on the grid, and forming a solidified electrode plate, characterized in that: : Applying cold extrusion to the grid after hot-casting; or adding a hydrated silicate to a lead paste formula that fills and cures the active material on the grid; or performs curing on the electrode plate with the active material During the formation, a pulsating current is used.

The method for manufacturing a lead base plate for a battery according to claim 1, wherein any two or three of the above three methods are used in combination.

The method for manufacturing a lead base plate for a battery according to claim 1, characterized in that the cold extrusion of the grid is to apply pressure from the outside to the inside.

The method for manufacturing a lead base plate for a battery according to claim 1, characterized in that the cold extrusion is applied to the grid once or more than once.

The method for manufacturing a lead base plate for a battery according to claim 1 or 3, wherein the pressure is 100-800 Kg / cm ² .

6. The method for manufacturing a lead base electrode plate for a battery according to claim 1, characterized in that the hydration silicate added to the formulation of the lead paste can be added to the positive lead paste, or the negative lead paste, Or added to the positive and negative lead paste formula at the same time.

7. The manufacturing method of claim 16 or the base plate of a lead storage battery as claimed in claim, wherein the hydrated silicate is montmorillonite, wherein montmorillonite composite molecular structure (Na, Ca) ₀ 33 (AL, Mg) ₂ (Si ₄ O ₁₀ ) (ΟΗ) ₂ · ηΗ ₂ 0,. = Positive integer.

The method for manufacturing a lead base plate for a battery according to claim 1 or 6, wherein the proportion of the hydrated silicate added to the lead paste formula is 0.1 to 3 weight percent of the lead paste formula. %.

The method for manufacturing a lead base electrode plate for a battery according to claim 1 or 6, wherein the hydrated silicate added to the lead paste formulation is subjected to an industrial acid impregnation treatment in advance.

10. The method for manufacturing a lead base electrode plate for a battery according to claim 1, wherein the electrode plate formation can be performed either before the battery or battery pack is assembled, or the green plate can be assembled into a battery or The battery pack becomes charged after charging.

The method for manufacturing a lead base electrode plate for a battery according to claim 10, wherein Pb ₃ 0 ₄ is not required to be added to the lead paste formulation after the green plate is assembled into a battery or a battery pack.

12. The method for manufacturing a lead base plate for a battery according to claim 1, wherein the pulsating current used in the formation is a periodic pulsating current, and the frequency is an arbitrary value.

13. The method for manufacturing a lead plate for a storage battery according to claim 1 or 12, wherein the waveform of the pulsating current is a square wave, a sawtooth wave, a negative pulse wave, a sine half wave, a sine full wave, or these Any combination of superimposed waves.

14. The method for manufacturing a lead base plate for a battery according to claim 1 or 12, characterized in that the current intensity of the pulsating current is greater than 0.2C, and the average charging voltage is 1-2 times the rated voltage of the battery or battery pack .