JP2006032026A - Manufacturing method of expanded grid for lead acid storage battery, grid by this, and lead acid storage battery using this grid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that in the manufacturing method of an expanded type grid for the lead acid storage battery, a complicated processing and equipment are required in the processing before working of the rolled sheet and that it was difficult to obtain a vertically elongated grid. <P>SOLUTION: The sheet obtained by rolling lead alloy is made into a state of overaging and then, by performing an expanding processing, a grid is made. It is desirable that the state of overaging is made by storing the sheet for 1.5-72 hours under 120°C or more and 160°C or less, and that the tensile strength of the sheet is made 6.0 kgf/mm<SP>2</SP>or less. Therefore, a vertically elongated grid of can be made and using the grid obtained and by assembling the electrode plate group under a pressurized state, a lead acid storage battery of high performance is obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing an expanded lattice for a lead storage battery, a lattice body thereby, and an improvement in a lead storage battery using the lattice.

  In the conventional process of expanding the grid of a lead storage battery, the sheet is processed after being heated to about 75 ° C. and about 90 ° C. at the maximum temperature (see, for example, Patent Document 1).

JP-A-5-258752 (columns 2-4)

  Moreover, although there exists what stores a sheet | seat at high temperature and stores it at low temperature after that, the storage at high temperature is 40 degreeC. (For example, refer to Patent Document 2).

JP-A-5-290855 (pages 3 to 4, [0017], FIG. 1)

  Lead-acid batteries have excellent cost performance and high reliability, and are used in a wide range of fields such as automobiles, communication equipment, uninterruptible power supplies. In particular, since the control valve type lead-acid battery can simplify the maintenance, it is also used in recent years for large power sources. In most cases, the lattice used for the electrode plate of this control valve type lead-acid battery is made of a lead-tin-calcium alloy. As a method for manufacturing the lattice body, there are a method in which an alloy is cast using a mold, or a method in which a sheet obtained by rolling an alloy slab is expanded. Since the expand method is excellent in productivity, it was originally applied to automobiles and the casting method was often applied to other uses. Recently, however, the expanded type has been adopted for lead-acid batteries for other purposes.

  In the expanding system, fine cuts are made in a sheet obtained by rolling a lead alloy, and the sheet is expanded in the direction of opening the cuts to obtain a rhombus cell having a required shape. At that time, the mesh may break depending on the properties of the alloy and the degree of expansion. For this reason, it is very difficult to obtain a lattice with a large rise angle of small bones (wires) forming a mesh, particularly a lattice with a longitudinal diagonal length longer than that of a horizontal diagonal. It was difficult. Here, the rising angle is formed so as to include a diagonal line in the horizontal direction among the angles formed by the small bones (wires) of the grid by opening the cut vertically in one grid of the expanded lattice. The angle is formed by a straight line connecting the apexes of the mesh (or the midpoint if the apex has a width) because the small bone (wire) may be curved. To do. As a countermeasure against this, there is a method in which a rolled sheet is subjected to an expanding process before being subjected to age hardening. For that purpose, in order to delay the progress of age hardening, means such as storing the sheet at a low temperature is necessary. Moreover, although the proposal which heats a sheet | seat is seen by said patent document 1 and 2, neither is for obtaining the softness | flexibility of a sheet | seat, but for adjusting the hardness of the sheet | seat before age hardening The heating temperature is low.

  In order to solve the above-mentioned problems, the present invention provides, in claim 1, characterized in that a sheet obtained by rolling a lead alloy is subjected to an expanding process after being overaged to obtain a lattice body. It is a manufacturing method of the expanded lattice body for lead acid batteries.

  In Claim 2, the overaging state is a state after the sheet is stored in an atmosphere of 120 ° C. or higher and 160 ° C. or lower for 1.5 hours to 72 hours, and the expanded lattice body for a lead storage battery according to claim 1. It is a manufacturing method.

In claim 3, the overaging state is a method for producing an expanded lattice body for a lead storage battery according to claim 2, wherein the tensile strength of the sheet at the time of expanding is 6.0 kgf / mm ² or less. .

  The grid body according to claim 4, wherein the expanded lattice has at least one or more rows where the rising angle of the wire forming the grid of the lattice body is 90 degrees or more and 120 degrees or less. It is a manufacturing method of the expanded grid | lattice body for lead storage batteries as described in a crab.

  In Claim 5, it is the grid for lead acid batteries obtained by the manufacturing method of Claim 1.

  According to a sixth aspect of the present invention, there is provided a lead-acid battery grid obtained by the manufacturing method of the second aspect.

  In Claim 7, it is the grid for lead acid batteries obtained by the manufacturing method of Claim 3.

  In Claim 8, it is the grid for lead acid batteries obtained by the manufacturing method of Claim 4.

  In Claim 9, the grid body according to any one of Claims 5 to 8 is used for at least one of a positive electrode and a negative electrode, and the electrode plate is assembled into a group of electrodes together with a compressible separator, on the surface of the electrode plate. It is a lead-acid battery inserted into the battery case with pressure applied vertically.

  According to claim 1, there is no need for a facility for delaying age hardening by storing a sheet obtained by rolling lead or a lead alloy at a low temperature, or a precise heating treatment facility directly connected to an expanding machine. Regardless of the storage conditions and period of the sheet, it is possible to stably produce an expanded lattice for a lead storage battery free from defects such as fracture of the mesh.

  According to the second and third aspects, specific conditions for reliably obtaining the effect of the first aspect are provided, and an expanded lattice body for a lead storage battery having no defects can be manufactured in a short time.

  According to the fourth aspect, in addition to the effects of the first to third aspects, it is possible to efficiently produce an expanded lattice for a lead storage battery that is particularly excellent in performance of large current density discharge. In other words, since this grid can be made vertically long even if sheets of the same width and thickness are used, it contributes to the weight reduction and conductivity improvement of the grid and is useful for the production of lead storage batteries with excellent output characteristics. It is.

  According to the fifth, sixth, seventh and eighth aspects, it is possible to provide a lattice body having an effect by the manufacturing method according to the first, second, third and fourth aspects, respectively.

  According to the ninth aspect, it is possible to provide a lead-acid battery having a sufficient practical life while exhibiting the effect of any one of the fifth to eighth aspects. In particular, when the grid body according to claim 8 is provided, it is possible to provide a lead-acid battery useful for engine start-up and an uninterruptible power supply for a short time (capable of large current discharge).

  The sheet used for the production of the grid of the present invention is generally produced by rolling a bar-shaped slab having a square cross section obtained by casting a lead alloy into a mold in succession with a multistage roll. You may supply this to a multistage roll, casting a slab from the melted lead alloy using the continuous casting machine which consists of a grooved drum and a belt.

  Lead alloys are generally ternary alloys of lead (Pb), calcium (Ca), and tin (Sn), and contain 0.02 to 0.11% by weight of Ca and 0.3 to 2.5% by weight of Sn. In general, the remainder is made of Pb. In order to improve performance, silver (Ag) or the like may be added thereto.

(Evaluation Test 1)
A lead alloy of Pb-0.07% Ca-1.5% Sn was melted in an electric furnace and cast into a mold at 550 ° C. to produce a slab having a width of 100 mm and a thickness of 10 mm. These slabs are rolled using a two-roll type rolling roll having a diameter of 450 mm at various rolling rates and rolling times (methods A to C) as shown in Table 1, and a sheet having a thickness of 0.9 mm is obtained. Produced. The rolling speed is 412 mm / sec. These sheets exhibited a tensile strength of 4.4 to 4.7 kgf / mm ² immediately after rolling, regardless of the rolling method.

  Next, Table 2 shows the tensile strength of the sheet after the sheet rolled by the methods A to C is stored in an atmosphere of 150 ° C. for 1.5 hours, 5 hours, and 11 hours to be in an overaged state. Tensile strength was obtained by taking 10 pieces of dumbbell-shaped samples from the obtained sheet in the rolling direction, measuring at a pulling speed of 30 mm / min, and excluding those showing the maximum and minimum values. Average values were taken.

FIG. 1 shows the transition of the tensile strength when a sheet that has been overaged under each of the above conditions is left in an atmosphere at 25 ° C. for 87 days. It can be seen that the overaged condition under any condition is stable in the range of ± 0.5 kgf / mm ² with respect to the tensile strength immediately after the overaged condition. Moreover, it turns out that there is almost no difference also by the rolling rate at the time of rolling a slab, and the frequency | count of rolling.

  Next, the sheet that has been stored in the above-described atmosphere at 150 ° C. for 1.5 hours, 5 hours, and 11 hours to be over-aged is subjected to re-propulsion type expansion processing machine. Although it was expanded so that the rising angles were 60 degrees, 90 degrees, and 120 degrees, none of the meshes broke.

From this, it can be seen that, under an atmosphere of 150 ° C., an overaged state having a tensile strength of 6.0 kgf / mm ² or less can be obtained by storing for 1.5 hours or longer. As a result, it is possible to obtain a grid body that does not break the grid even if the rising angle of the wire forming the grid of the grid body is expanded to 120 degrees.

(Evaluation test 2)
Next, the sheet rolled by the method A is stored in each atmosphere of 100 ° C., 120 ° C., 140 ° C. and 160 ° C., and the situation from age hardening to overaging is stored in the atmosphere of 100 ° C. and 120 ° C. The tensile strength was measured every 24 hours and stored at 140 ° C. and 160 ° C. every 30 minutes, and the tensile strength was in the range of 4.0 to 6.0 kgf / mm ^2. The time until the aging state is reached (over-aging treatment time) is measured, and the result is shown in FIG. The reason why the tensile strength is in the range of 4.0 to 6.0 kgf / mm ² is that, in Evaluation Test 1, even when the rising angle of the wire is 120 degrees, the mesh does not break. And the sheet | seat of the grid | lattice body is formed with the reciprocating type expansion processing machine by storing in each said atmosphere, and the sheet | seat in which the tensile strength became the range of 4.0-6.0kgf / mm < ² >. The wire was expanded so that the rising angle was 60 degrees, 90 degrees, and 120 degrees, but none of the breaks occurred in the mesh.

From FIG. 2, the overaging treatment time is about 1.5 hours, preferably about 1-2 hours if the temperature is 160 ° C., and about 9.5 hours if the temperature is 140 ° C., preferably Storage for about 9 to 10 hours, about 60 hours if the temperature is 120 ° C, preferably about 48 to 72 hours, about 240 hours if the temperature is 100 ° C, preferably about 1 to 2 weeks It is good to do. In addition, it is considered that the reason why the storage period is thus widened is that the tensile strength is in the range of 4.0 to 6.0 kgf / mm ² from the relationship between the passage of the storage period at each ambient temperature and the tensile strength. Estimated period.

  On the other hand, since the sheet is in an overaged state after its tensile strength has passed the peak, the sheet is left at room temperature (25 ° C.) after the storage in the atmosphere described above. However, the tensile strength does not change greatly, and the value is stable in a range suitable for expanding over a long period of time, as can be seen from FIG. 1, so that it is used for expanding without considering the inventory period. This is industrially advantageous.

  In the above-described evaluation test 1, as shown in the methods A to C, the slab having a thickness of 10 mm was changed to a sheet having a thickness of 0.9 mm by changing the rolling conditions. The rolling rate of each round was 23% to 55%, and the number of rolling was changed. The results were the same in any of the methods A to C. Therefore, in the evaluation test 2 described above, the rolling rate of each slab was about 33% and the number of rollings was 6 times, but what kind of rolling conditions were selected depends on the number of rolling roll sets, What is necessary is just to determine suitably according to the thickness of the slab which can be produced, and the thickness of a sheet | seat.

(Evaluation Test 3)
Next, for lead alloys of Pb—Ca—Sn, lead alloys having Sn weight percentages of 1.5% and Ca weight percentages of 0.02%, 0.04%, and 0.07% were evaluated. As in Test 1, it was melted in an electric furnace, cast into a mold at 550 ° C., and a slab having a width of 100 mm and a thickness of 10 mm was prepared. These slabs are rolled using a two-roll type rolling roll having a diameter of 450 mm at various rolling rates and the number of rolling operations (methods A to C) as shown in Table 1 to produce a sheet having a thickness of 0.9 mm. did. The rolling speed is 412 mm / sec. About these sheets, when the tensile strength immediately after rolling was measured by the same method as that measured in Evaluation Test 1, it was 4.4 to 4.8 kgf / mm ² in any of the methods A to C. .

  Next, each of the above-described sheets is left as it is in an atmosphere of 25 ° C., and the transition of the tensile strength in the process from the age hardening to the overaging state is investigated, and the results are shown in FIG.

From FIG. 3, it can be seen that the peak value of the tensile strength increases as the weight percentage of Ca increases, and the time to reach the peak value is shorter. In addition, the peak value was 6.0 kgf / mm ² or less when overaged as in Evaluation Test 1, whereas the component ratio was as follows when overaged from age hardening as described above. It turns out that it is about 8.0 kgf / mm < ² > in the same thing used for the evaluation test 1. FIG. Moreover, it turns out that the value of the tensile strength is substantially maintained after going from an age hardening to an overaging state in this way.

(Evaluation Test 4)
Next, regarding the lead alloy of Pb—Ca—Sn, the Ca wt% is set to 0.07%, and the Sn wt% is set to 0%, 0.3%, 0.5%, 0.7%, and 1. The lead alloys with 0% and 1.5% were melted in an electric furnace in the same manner as in the evaluation test 1 and cast into a mold at 550 ° C. to produce a slab having a width of 100 mm and a thickness of 10 mm. These slabs are rolled using a two-roll type rolling roll having a diameter of 450 mm at various rolling rates and the number of rolling operations (methods A to C) as shown in Table 1 to produce a sheet having a thickness of 0.9 mm. did. The rolling speed is 412 mm / sec. About these sheets, when the tensile strength immediately after rolling was measured by the same method as that measured in Evaluation Test 1, it was 4.3 to 4.9 kgf / mm ² in any of the methods A to C. .

  Next, the transition of the tensile strength when each of the above-mentioned sheets is left as it is in an atmosphere of 25 ° C. is investigated, and the results are shown in FIG.

FIG. 4 shows that the peak value of the tensile strength increases as the weight percentage of Sn increases, and the time to reach the peak value is shorter. In addition, the peak value was 6.0 kgf / mm ² or less when overaged as in Evaluation Test 1, whereas the component ratio was as follows when overaged from age hardening as described above. It turns out that it is about 8.0 kgf / mm < ² > in the same thing used for the evaluation test 1. FIG. Moreover, it turns out that the value of the tensile strength is substantially maintained after going from an age hardening to an overaging state in this way.

  Next, a sheet made of a lead alloy of Pb-0.07% Ca-1.5% Sn prepared in the above-described evaluation tests 3 and 4 and allowed to stand for 10 days in an atmosphere at 25 ° C. is used as a reciprocating type expander. When the rising angle of the wire forming the grid of the lattice body is expanded by the processing machine so that it is 60 degrees, 90 degrees and 120 degrees, when the rising angle becomes 90 degrees, some breaks occur, It was found that when the angle was 120 degrees, the cuts and the meshes were broken to such an extent that continuous expansion could not be performed.

  From this, according to the manufacturing method of the expanded lattice body of the present invention, when a sheet made of a lead alloy of Pb-0.07% Ca-1.5% Sn is expanded, the rising angle of the wire is 120 degrees. A lattice body that does not cause breakage of the mesh even when it is expanded to a maximum is obtained. Here, the expansion angle of the wire to 120 degrees may be applied to all the grids of the lattice, or one or more such horizontal rows may be provided. In particular, among the horizontal rows, the rows close to the upper and lower master bones are expanded so that the rising angle of the wires is smaller than 120 degrees, and the rising angles of the wires in the remaining rows are expanded so as to be 120 degrees. If opened, it is possible to obtain an electrode plate having a uniform thickness according to the rising angle of the wires in the rows close to the upper and lower master bones.

  That is, from the results of the above-described evaluation tests 3 and 4, even if the weight percent of Ca and the weight percent of Sn are changed, they are once stored at the above temperature, for example, at 150 ° C. for 1.5 hours or more, If the sheet is in an over-aged state after the peak tensile strength has passed the peak value, the tensile strength will be maintained over a long period of time even if there is a difference in the length of the subsequent standing period or the standing temperature at that time. Since it is stable in a range suitable for expanding, it can be used for expanding without considering the inventory period, which is industrially advantageous.

  From the results of the above evaluation tests 1 to 4, the tensile strength of the lattice body obtained by the expanding process and the conditions of the sheet produced by rolling the lattice body from what slab were determined. It can be seen that the level of strength is determined. That is, if the alloy composition of the lattice body obtained by disassembling the lead storage battery is known, it is a lattice body obtained by expanding a flexible sheet immediately after rolling, or the sheet is, for example, 1 in an atmosphere at 150 ° C. A grid obtained by expanding after storage for 5 hours or more, or a grid obtained by expanding the sheet after leaving it at room temperature (25 ° C.) for a long period of time. It can be determined from the level of tensile strength.

  In each of the above evaluation tests, a reciprocating type expand processing machine was used, but even when using a rotary type, if a sheet having an appropriate tensile strength according to the present invention is used, the shape of the mesh is stable, A lattice body without defects can be manufactured.

  The lattice body according to the present invention is used as a lead-acid battery, and has a feature of exhibiting effects equivalent to or higher than those of conventional products with little partial corrosion and elongation. This is presumably because the tensile strength of the sheet is small and it is subjected to the expanding process in a flexible state, so that the internal stress due to deformation accompanying the process is small.

Next, after the sheet produced by Method A in the above Evaluation Test 1 is expanded, the paste as an active material is filled by a conventional method, thin paper is attached to both sides, and after drying, punching, and cutting Then, lay out in units of several tens of sheets and age them to make unformed electrode plates. When the positive and negative electrode plates thus obtained are stacked together with a glass mat and a separator plate to form an electrode plate group (five positive electrode plates, six negative electrode plates, and five micro-hole separator plates), the electrode plates are horizontal. A stacker that handles in a state close to this can be preferably used. Moreover, the electrode plate is reinforced by the thin paper on the surface and the cement effect of the aging paste, and other stacking machines can be used. The electrode plate group thus obtained is fixed and attached with a strap for collecting current and necessary terminals to form a pole group, and the electrode group is pressed in a direction perpendicular to the surface of the electrode plate to obtain a predetermined current. Store in the tank. The unformed lead-acid battery thus obtained is injected with an electrolyte and energized to carry out formation, and if necessary, an exhaust valve is attached to obtain a finished lead-acid battery. The lead storage battery of the present invention thus obtained has a lattice body having a tensile strength of 4.0 to 6.0 kgf / mm ² and a lattice body obtained by expanding a sheet after being stored at a low temperature. Although it is lower than the tensile strength (7.0 kgf / mm ² ) of the grid of the lead storage battery, a fine glass fiber mat is used for the separator of the pole group, and a pressure of ²⁰ to 60 kgf / dm ² is applied to the pole plate, It is suitable for a control valve type lead storage battery in which the amount of electrolyte is limited and absorbed by a fine glass fiber mat. In this case, even if the thickness of the sheet after rolling is as thin as about 1 mm (0.9 mm) as described above, the active material is sufficiently held in the lattice, and the durability of the battery is expected to be improved. be able to. Of course, it can also be used for a lead-acid battery that uses a sufficient amount of electrolyte using a normal glass fiber mat and a microporous separator. Moreover, the well-known fixing method of the pole group for improving vibration resistance and impact resistance can be used in combination.

  According to the present invention, a sheet obtained by rolling a lead alloy is made into an over-aged state and then subjected to expansion processing to form a lattice body, whereby a vertically long lattice body can be produced and obtained. If a grid body is used and the pole group is assembled in a compressed state, a high-performance lead-acid battery can be obtained, so the industrial applicability is great.

The figure which shows the influence of the days to leave on the tensile strength after the overaging process of a Pb-0.07% Ca-1.5% Sn alloy sheet. The figure which shows an example of the relationship between the tensile strength and storage temperature of a Pb-0.07% Ca-1.5% Sn alloy sheet. The figure which shows the condition of the age hardening of the Pb-Ca-Sn alloy sheet at the time of changing the composition of Ca. The figure which shows the condition of age hardening of the Pb-Ca-Sn alloy sheet at the time of changing the composition of Sn.

Claims (9)

A method for producing an expanded lattice for a lead storage battery, wherein a sheet obtained by rolling a lead alloy is made into an over-aged state and then subjected to expansion processing to form a lattice. The method for producing an expanded lattice for a lead-acid battery according to claim 1, wherein the overaging state is a state after the sheet is stored in an atmosphere of 120 ° C or higher and 160 ° C or lower for 1.5 hours to 72 hours. The method for producing an expanded lattice body for a lead-acid battery according to claim 2, wherein the overaging state is a state in which the tensile strength of the sheet when performing the expanding process is 6.0 kgf / mm ² or less. The lead-acid battery according to any one of claims 1 to 3, wherein the expanded lattice has one or more rows in which the rising angles of the wires forming the grid of the lattice are not less than 90 degrees and not more than 120 degrees. For producing an expanded lattice for use. The grid for lead acid batteries obtained by the manufacturing method of Claim 1. The grid for lead-acid batteries obtained by the manufacturing method according to claim 2. The grid for lead acid batteries obtained by the manufacturing method of Claim 3. The grid for lead acid batteries obtained by the manufacturing method of Claim 4. The grid body according to any one of claims 5 to 8 is used for at least one of a positive electrode plate and a negative electrode plate, the electrode plate is assembled into a group of electrodes together with a compressible separator, and pressure is applied perpendicularly to the electrode plate surface. Lead-acid battery inserted into the battery case in a live state.

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