JP2019153384A - Positive electrode grid body for lead acid battery and lead acid battery - Google Patents

Abstract

To improve the life of lead acid battery, by preventing internal short circuit resulting from a positive electrode grid body.SOLUTION: A positive electrode grid body includes: a rectangular frame shape frame bone having first and second horizontal frame bones extending crosswise, and first and second vertical frame bones extending in the vertical direction; an inner bone placed in the frame bone, and having multiple horizontal rails and muntins provided in a lattice while being connected with the frame bone; multiple openings provided as a region surrounded by the frame bone and the multiple horizontal rails and muntins, and a region surrounded by the multiple horizontal rails and muntins; and a positive electrode collector lug. Average area of the multiple openings adjacent to the first and second vertical frame bones is smaller than the average area of the remaining multiple openings excepting the multiple openings, and when comparing on the same perpendicular traversing the first and second horizontal frame bones, the area of the multiple openings decreases gradually from the second horizontal frame bone side toward the first horizontal frame bone side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a positive electrode grid for a lead storage battery and a lead storage battery.

  In order to cope with the recent serious environmental problems and exhaust gas regulations, automobiles equipped with an idling stop function (hereinafter referred to as “ISS cars”) for temporarily stopping the engine when the vehicle is stopped are becoming widespread. The ISS vehicle can suppress fuel consumption due to idling when the vehicle is stopped due to a signal or the like, thereby improving fuel efficiency and reducing the amount of exhaust gas.

  It is known that the lead-acid battery mounted on the ISS vehicle is likely to reach an early life. The reason for this is that in ISS cars, when the engine stops due to a signal, etc., power is supplied to devices such as air conditioners, lights, wipers, car navigation systems, etc. It can be mentioned that a large load is applied to the lead storage battery by repeating discharge for restarting the engine and charging by an alternator or a regenerative brake.

  A lead storage battery is manufactured through a process of pouring dilute sulfuric acid, which is an electrolytic solution, into the battery case after the electrode plate group having a laminated structure is housed in the battery case. In the electrode plate group having a laminated structure, a positive electrode plate and a negative electrode plate, and a separator, which are mainly made of lead or a lead alloy and filled with a paste-like active material, are alternately laminated. As the lattice body, for example, a structure having a frame bone and an inner bone surrounded by the frame bone is known. The frame bone includes the first horizontal frame bone arranged on the upper side and forming the current collecting ear, the second horizontal frame bone arranged on the lower side, and the ends of the first and second horizontal frame bones. And first and second vertical frame bones to be connected. The inner bone has a plurality of horizontal bars and vertical bars. In the lattice body, at least an opening defined as a region surrounded by the frame bone and the inner bone is filled with an active material.

  One of the life factors of such a lead storage battery is the expansion and deformation of the entire positive electrode lattice body accompanying corrosion and expansion of the positive electrode lattice body. Such deformation of the positive electrode lattice is called growth. When the growth occurs, a part of the positive electrode lattice is bent and broken, and the broken end breaks through the separator and comes into contact with the opposing negative electrode plate, or expands upward and comes into contact with a part of the negative electrode such as a negative electrode strap. As a result, an internal short circuit may occur, and the lead-acid battery may reach the end of its life. Further, the growth of the positive electrode lattice causes peeling or dropping of the positive electrode active material, which causes an early capacity decrease. Under these circumstances, it is necessary to take measures against the growth of the positive electrode grid when designing a lead-acid battery.

The mechanism of growth is considered as follows. Corrosion in a lead-acid battery is caused by PbO _x (x: 1 to 2) or PbSO ₄ reacting with sulfate ions contained in the electrolytic solution or the active material, mainly lead or lead alloy that forms a positive electrode grid body by charging and discharging. This results from an oxidation reaction that changes into a corrosion reaction product having a multi-layer structure composed of, and the like. The corrosion proceeds with repeated charge / discharge. At this time, a layer of the corrosion reaction product grows in the vicinity of the surface of the positive electrode lattice body in contact with the electrolytic solution. Since the growth of the corrosion reaction product is accompanied by an increase in the volume of the positive electrode lattice body, when corrosion progresses, a large stress is caused by the difference in the degree of expansion between the corrosion reaction product near the surface of the positive electrode lattice body and the internal positive electrode lattice body itself. Will occur. As a result, the stress becomes a tensile stress that stretches the positive electrode lattice body, and grows due to expansion of the entire positive electrode lattice body.

  The electrode plate group of the lead-acid battery is fixed to the top of the lid or battery case by a pole column or cell connecting member that extends upward from the strap, so when growth occurs, the positive electrode plate is fixed first It stretches against the left and right sides and the lower side. In the initial growth, the extension allowance to the lower side is often smaller than the extension allowance to the left and right sides of the positive electrode plate. This is because, in order to support the electrode plate group, the lower end of the electrode plate group is in contact with the bottom surface of the battery case or the flange provided on the bottom surface. Therefore, when the growth occurs, the downward extension of the positive electrode plate turns to the upward extension, so that the upper end of the positive electrode plate may come into contact with a part of the negative electrode such as the negative electrode strap to cause an internal short circuit.

  As a means for preventing an internal short circuit due to growth on the upper side of the positive electrode grid body, the applicant described in Patent Document 1 and Patent Document 2 that a lead storage battery in which a collar portion of a battery case holding an electrode plate group is formed of a sponge or a foamed resin Has proposed. By forming the ridge part of the battery case with sponge or foamable resin, when the growth occurs in the positive electrode grid body, the heel part is crushed and absorbs the downward extension, so the upward extension of the positive electrode grid body is suppressed. Thus, contact with the negative strap or the like and internal short circuit can be prevented.

  On the other hand, various inventions that suppress the internal short circuit between the positive electrode lattice body and the negative electrode lattice body in a form different from the configurations of Patent Documents 1 and 2 have been proposed. Patent Document 3 discloses a lead storage battery having a structure in which a positive electrode plate is suspended and the lower side of the positive electrode plate is separated from the bottom of the battery case. In this lead storage battery, since the positive electrode plate preferentially extends downward when growth occurs, an internal short circuit due to the upward extension and the contact between the positive electrode plate and the negative electrode plate is suppressed.

  In Patent Documents 4 and 5, as a method for suppressing contact between the positive electrode plate and the negative electrode plate due to growth, a lead storage battery in which a portion having a low mechanical strength such as a notch or a constriction is provided in a predetermined portion of the positive electrode grid. Is disclosed. In this way, by forming a portion having a low mechanical strength in a part of the positive electrode lattice body, when growth occurs, a portion having a low mechanical strength is preferentially broken or deformed, and the entire positive electrode lattice body is Expansion is suppressed.

  In addition to the technique for suppressing the growth of the positive electrode grid due to corrosion, it has been studied to improve the life of the lead-acid battery by preventing deformation due to expansion and contraction of the active material during the charge / discharge cycle.

  Patent Document 6 discloses a lead-acid battery in which the arrangement interval of the horizontal bars and vertical bars constituting the inner bone is reduced from the central part toward the peripheral part in the positive electrode lattice body. In this way, the horizontal and vertical bars are arranged closer to the periphery of the positive grid by reducing the arrangement interval of the horizontal and vertical bars from the center toward the periphery. The mechanical strength is improved. Therefore, especially the deformation | transformation to a horizontal direction of the positive electrode grid body when a positive electrode active material expand | swells to a surface direction by charge is suppressed, and the cycling characteristics of a lead storage battery improve.

JP 2001-351671 A Japanese Utility Model Publication No. 5-45901 JP 2012-079609 A Japanese Patent No. 5103385 JP 2013-16499 A JP-A-2-281563

However, the lead storage batteries described in Patent Documents 1 to 3 are intended for stationary storage power storage batteries that are used in a stationary state. There was a point that should be improved in durability. In the lead-acid batteries described in Patent Documents 1 to 3, since the heavy electrode plate group is supported and held only by the current collecting ear connected to the upper strap, the electrode plate group is formed when intense vibration is applied. There is a risk of breakage at the current collecting ear.
On the other hand, in the lead storage batteries described in Patent Literature 4 and Patent Literature 5, since a notch or a constriction is provided in a part of the positive electrode grid body, the electrical resistance locally increases in the part, and the potential distribution during charging and discharging is increased. There is a possibility that the current collection efficiency is lowered due to non-uniformity and the output characteristics and the like are lowered. In addition, when notches and constricted portions are provided, the shape of the mold used for manufacturing the positive electrode grid is complicated, which may increase manufacturing costs and yield. In particular, in the production of a positive electrode grid body by casting, there is a risk of casting defects such as breakage due to poor hot water of molten lead or lead alloy in the mold.

  As in the positive electrode grid body described in Patent Document 6, when the arrangement interval between the horizontal bars and the vertical bars constituting the inner bone is reduced from the central part toward the peripheral part, openings located in the peripheral part of the positive electrode grid body Is smaller in area than that located at the center of the positive electrode grid, and the area of the opening located at the center of the positive grid is increased. Generally, the current density at the time of charging / discharging in the positive electrode grid body is larger as it is located near the upper positive electrode current collecting ear and smaller as it is located on the lower side. Further, the positive electrode active material expands and contracts with the charge / discharge reaction, and the charge / discharge reaction is proportional to the current density. For this reason, the expansion and contraction of the positive electrode active material are large on the upper side of the positive electrode lattice, and are small on the lower side. As a result, as in Patent Document 6, when the distribution of the area of the opening is made point-symmetric with respect to the central portion of the positive electrode lattice, the expansion and contraction of the positive electrode active material are not necessarily taken into account when the current density distribution is taken into consideration. It was not the most efficient way to prevent it, and there was room for improvement. Moreover, as described in Patent Document 6, increasing the number of horizontal bars and vertical bars leads to an increase in the weight of the lead storage battery itself. Therefore, if the arrangement interval of the horizontal crosspieces and the vertical crosspieces is close to the lower side of the positive electrode grid body which has a small contribution to prevention of expansion and contraction of the positive electrode active material, weight reduction of the lead storage battery is impaired.

  Further, the mechanism found by the inventors and the like to promote growth will be described below. When the positive electrode lattice body is deformed so as to expand due to the growth, the positive electrode active material is peeled off from the frame bone and the inner bone, dropped from the opening, or a gap is generated. When the electrolytic solution enters the gap and comes into contact with the positive electrode grid body, corrosion of the positive electrode grid body accompanying charge / discharge is promoted, so that growth proceeds at an accelerated rate. Hereinafter, the remarkable progress of the growth accompanying the peeling or dropping off of the positive electrode active material in contact with the vertical frame bone of the positive electrode lattice body will be referred to as “accelerated growth”. In general, it is known that the larger the cross-sectional area of the positive electrode lattice body, the greater the degree of growth during corrosion. Therefore, when the vertical frame bone of the positive electrode grid body is bent outward, peeling or dropping from the positive electrode active material causes not only a decrease in battery performance such as discharge capacity and output characteristics, but also acceleration in the vertical direction. Invite a healthy growth.

  In addition, if the positive electrode active material and the positive electrode grid are in close contact with each other, a corrosive layer necessary for bonding is formed between the positive electrode active material and the surface of the positive electrode grid. When the corrosive layer is interposed between the positive electrode active material and the positive electrode grid, the positive electrode active material exerts a force that pulls the positive electrode grid, thereby suppressing the growth of the positive electrode grid. However, in the state where peeling or dropping occurs, the above action does not work, and accelerated growth is promoted.

  In view of the above circumstances, an object of the present invention is to provide a positive electrode lattice body for a lead storage battery and a lead storage battery that can prevent an internal short circuit due to the growth of the positive electrode lattice body and improve the life of the lead storage battery.

  In order to solve the above-described problem, according to one embodiment, a first horizontal frame bone and a second horizontal frame bone extending in a lateral direction, a first vertical frame bone and a second vertical frame extending in a vertical direction are provided. A rectangular frame-shaped frame bone including a frame bone; an inner bone provided with a plurality of horizontal bars and vertical bars arranged in a grid connected to the frame bone; and a frame frame and a plurality of horizontal frames A region surrounded by the crosspiece and the vertical crosspiece, and a plurality of openings defined as a region surrounded by the plurality of horizontal crosspieces and the vertical crosspiece; and a positive electrode current collecting ear connected to the first horizontal frame bone; The average area of the plurality of openings adjacent to the first vertical frame bone and the plurality of openings adjacent to the second vertical frame bone in a plan view is the plane of the remaining plurality of openings excluding the plurality of openings. Compared to the average area seen, the plurality of openings are compared on the same vertical line that cuts the first and second frame bones vertically. If a lead-acid battery positive grid body, wherein a surface area which is stepwise plan view toward the second lateral frame bone side to the first lateral frame bone side is reduced is provided.

  In order to solve the above-described problems, according to another embodiment, a lead storage battery including the above-described positive electrode grid for a lead storage battery is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the internal short circuit resulting from the growth of a positive electrode grid body can be prevented, and the positive electrode grid body and lead acid battery for lead storage batteries which can improve the lifetime of a lead storage battery can be provided.

FIG. 1 is a plan view of the positive electrode grid according to the first embodiment. FIG. 2 is a plan view of the positive electrode grid according to the second embodiment. FIG. 3 is an enlarged plan view showing an opening provided in the positive electrode grid according to the third embodiment. FIG. 4 is an enlarged plan view showing an opening provided in the positive electrode grid according to the fourth embodiment. FIG. 5 is an enlarged plan view showing a part of the positive electrode lattice body according to the fifth embodiment. FIG. 6 is an enlarged plan view showing a part of the positive electrode lattice body according to the sixth embodiment. FIG. 7 is an enlarged plan view showing a part of the positive electrode lattice body according to the seventh embodiment.

<First Embodiment>
FIG. 1: shows the top view of the positive electrode grid 1 for lead acid batteries which concerns on 1st Embodiment.

  The positive electrode lattice body 1 includes a frame bone, an inner bone arranged in the frame bone, and a positive electrode current collecting ear 11A. The frame bone has a rectangular frame shape, and extends in the horizontal direction X. The first horizontal frame bone 13a and the second horizontal frame to which the positive electrode current collecting ear 11A is connected at a position shifted from the middle of the horizontal direction X. A bone 13b, a first vertical frame bone 14a extending in the vertical direction Y, and a second vertical frame bone 14b are provided. In the present specification, as shown in FIG. 1, the direction in which the first horizontal frame bone 13a and the second horizontal frame bone 13b extend is the horizontal direction X, and the first vertical frame bone 14a and the second vertical frame. The direction in which the bone 14b extends is defined as the longitudinal direction Y. Further, the part where the first horizontal frame bone 13a is arranged is the upper side, the part where the second horizontal frame bone 13b is arranged is the lower side, the part where the first vertical frame bone 14a is arranged is the left side, the second The part where the vertical frame bone 14b is arranged is defined as the right side.

  In the frame bone, an inner bone is arranged which is connected to the frame bone and includes a plurality of horizontal bars 15a and vertical bars 15b arranged in a lattice pattern. The plurality of horizontal bars 15a are connected to, for example, the first vertical frame bone 14a and the second vertical frame bone 14b, respectively, and extend in the horizontal direction X. In addition, the plurality of horizontal bars 15a are arranged in parallel and spaced apart from each other in the vertical direction Y, for example. The plurality of vertical bars 15b are connected to the first horizontal frame bone 13a and the second horizontal frame bone 13b, respectively, and extend in the vertical direction Y. Further, the plurality of vertical bars 15b are arranged in parallel and spaced apart from each other in the horizontal direction X, for example. The plurality of horizontal bars 15a and the plurality of vertical bars 15b are arranged so as to intersect at right angles, for example.

  In the positive electrode grid 1, the plurality of openings 16 are defined by a region surrounded by the frame bone and the plurality of horizontal rails 15a and the vertical rails 15b, and a region surrounded by the plurality of horizontal rails 15a and the vertical rails 15b. The The plurality of openings 16 each have a rectangular shape, for example.

  The plurality of vertical bars 15b includes a distance between the vertical bars 15b adjacent to the first and second vertical frame bones 14a and 14b and the first and second vertical frame bones 14a and 14b, and other vertical frames. When comparing the interval between the crosspieces 15b, the interval between the first and second vertical frame bones 14a and 14b and the adjacent vertical crosspieces 15b is narrower than the interval between the other plurality of vertical crosspieces 15b. Is arranged. Therefore, the average area in plan view of the plurality of openings 16 adjacent to the first vertical frame bone 14a and the plurality of openings 16 adjacent to the second vertical frame bone 14b is a plurality of other than that The opening 16 is smaller than the average area in plan view.

  Further, the plurality of horizontal rails 15a are stepwise from, for example, the second horizontal frame bone 13b side (ie, the lower side in FIG. 1) to the first horizontal frame bone 13a side (ie, the upper side in FIG. 1). Are arranged so that the interval is narrow. Therefore, the area of the plurality of openings 16 in a plan view gradually decreases from the second lateral frame bone 13b side toward the first lateral frame bone 13a side. At this time, the area of the plurality of openings 16 in plan view is the area of the opening 16 on the second lateral frame bone 13b side from the second lateral frame bone 13b side to the first lateral frame bone 13a side. However, it is preferable to reduce the size stepwise within a range not exceeding 0.85 times and 0.99 times. For example, in the example shown in FIG. 1, the area ratio of one opening portion 16 located in the y-th row of the same column with respect to the area of the opening portion 16 located in the y + 1-th row counted from the upper side is 0. 85 times, up to 0.99 times.

  11 A of positive electrode current collection ears for connecting the positive grid 1 to the exterior are connected to the 1st horizontal frame bone 13a. The positive electrode current collector ear 11A has, for example, a rectangular plate shape, and is connected so as to extend upward from the right side of the first horizontal frame bone 13a in FIG. When a positive electrode plate and a negative electrode plate are laminated to form an electrode plate group as will be described later, the positive electrode current collector ear 11A and the negative electrode current collector ear 11B are first viewed when viewed in the stacking direction of the electrode plate group. The lateral frame bones 13a are arranged so as to be shifted from each other in the length direction. In the example illustrated in FIG. 1, the positive electrode current collector ear 11 </ b> A and the negative electrode current collector ear 11 </ b> B are disposed at positions symmetrical to each other with respect to the center line in the horizontal direction X of the positive electrode grid 1.

  Next, the operation of the positive electrode grid body 1 according to the first embodiment will be described.

  The average area of the plurality of openings 16 adjacent to the first vertical frame bone 14a and the plurality of openings 16 adjacent to the second vertical frame bone 14b in plan view is the remaining plurality excluding the plurality of openings 16 Smaller than the average area of the openings 16. Thus, the average area of the plurality of openings 16 adjacent to at least the first vertical frame bone 14a and the plurality of openings 16 adjacent to the second vertical frame bone 14b in plan view is determined as the plurality of openings. By making it smaller than the average area of the remaining plurality of openings 16 excluding 16, the ratio of the positive electrode active material filled in the plurality of openings 16 in contact with a certain area of the positive electrode grid 1 is different from that of the other. This is larger than the positive electrode active material filled in the plurality of openings 16. Therefore, the adhesiveness between the positive electrode active material filled in the plurality of openings 16 and the positive electrode grid body 1 is improved as compared with other portions, and separation or dropping of the positive electrode active material can be suppressed. Therefore, it is possible to suppress a decrease in battery performance such as discharge capacity and output characteristics associated with peeling or dropping of the positive electrode active material filled in the plurality of openings 16. At the same time, it is possible to prevent accelerated growth of the first vertical frame bone 14a and the second vertical frame bone 14b of the positive electrode grid body 1.

  In order to reduce the area when the opening 16 of the positive electrode grid 1 is viewed in plan, for example, the width of the frame bone, the horizontal beam 15a or the vertical beam 15b forming the opening 16 is increased, or the same area is formed. A method such as increasing the number of the horizontal bars 15a or the vertical bars 15b in FIG. However, since both have a trade-off relationship with the increase in the weight of the positive electrode grid 1, the reduced area of the average area in plan view of the opening is adjacent to the first vertical frame bone 14a and the second vertical frame bone 14b. It is desirable to limit it to a part.

  The plurality of openings 16 are the first horizontal frame bones from the second horizontal frame bone 13b side when compared on the same vertical line that longitudinally cuts the first horizontal frame bone 13a and the second horizontal frame bone 13b. The area in plan view is reduced stepwise toward the 13a side. As described above, the opening 16 having a small area located on the upper side of the positive electrode grid body 1 has a constant area per area of the positive electrode grid body 1 as compared with the opening 16 having a large area located on the lower side of the positive electrode grid body 1. The ratio of the positive electrode active material in contact with increases. For this reason, the adhesiveness of the positive electrode active material with which the said opening part 16 was filled, and the positive electrode grid body 1 improves, and it becomes possible to prevent the accelerated growth of the positive electrode grid body 1. FIG. Here, the area ratio of the plurality of openings 16 continuous vertically is such that the area of the upper opening 16 is not less than 0.85 times and not more than 0.99 times with respect to the lower opening 16, that is, The area ratio of (upper opening) / (lower opening) = 0.85 to 0.99 times is more desirable in preventing accelerated growth. When the area ratio exceeds 0.99 times, since the area difference between the upper side and the lower side of the positive electrode grid body 1 is small, the effect of selectively enhancing the reinforcement on the upper side of the positive electrode grid body 1 is reduced. Further, when the area ratio is less than 0.85 times, the filling of the positive electrode active material is improved by reducing the upper opening 16 of the positive electrode grid 1, but the area of the lower opening 16 is relatively small. May increase and the output characteristics and the retention of the positive electrode active material may be reduced.

  When the first lateral frame bone 13a and the second lateral frame bone 13b are compared on the same vertical line in the plurality of openings 16 described above, the first lateral frame bone 13b side is compared with the first lateral frame bone 13b side. The operation of suppressing the growth of the positive electrode lattice 1 due to the expansion and contraction of the positive electrode active material by gradually reducing the area in plan view toward the frame bone 13a will be described.

  When the positive electrode active material expands and contracts due to charge and discharge, the expansion and contraction force is propagated from the central portion of the positive electrode lattice body 1 toward the outer peripheral portion. According to research by the inventors, the first and second vertical frame bones 14a and 14b are particularly elongated as a sum of the propagation, and in the openings adjacent to the first and second vertical frame bones 14a and 14b. It has been found that the positive electrode active material tends to be peeled off or detached. Peeling or dropping off can be suppressed to some extent by reducing the area in plan view of the plurality of openings 16 adjacent to the first and second vertical frame bones 14a, 14b. Further, by reducing an area difference (a volume difference when the thickness of the positive electrode grid body 1 is constant) in plan view of the openings 16 continuously arranged in the vertical direction on the same perpendicular line, the openings continuous in the vertical direction. It was found that the interfacial stress generated between the openings 16 can be relaxed by the difference between the expansion force and the contraction force of the positive electrode active materials between the 16 positive electrodes, and the positive electrode active material can be more remarkably suppressed from peeling off or falling off.

  For this reason, the area of the plurality of openings 16 in plan view is reduced as approaching from the lower second lateral frame bone 13b side to the upper first lateral frame bone 13a side on the same vertical line. As a result, accelerated growth is likely to occur, and interface stress generated between the surface of the positive electrode grid 1 and the positive electrode active material between the openings 16 is relaxed on the upper side of the positive electrode grid 1 where the positive electrode active material is significantly expanded and contracted. In addition, peeling or dropping of the positive electrode active material can be prevented.

  Further, in the above configuration, the number of the horizontal bars 15a and the vertical bars 15b that occupy the positive electrode grid body 1 becomes relatively higher as the position is higher on the positive electrode grid body 1, so that the mechanical strength on the upper side of the positive electrode grid body 1 is increased. improves. Therefore, even if growth occurs upward, the horizontal rail 15a located on the upper side of the positive electrode grid body 1 suppresses upward bending, and the upper part of the positive electrode plate and a part of the negative electrode such as the negative electrode plate or the negative electrode strap. Internal short circuit due to contact can be suppressed. In addition, the number of horizontal bars 15a and vertical bars 15b in the positive grid 1 is relatively small on the lower side of the positive grid 1 that is less affected by expansion and contraction of the positive electrode active material. Is not impaired.

  In addition, the frame bone which comprises the positive electrode grid 1, the inner bone provided with the plurality of horizontal bars 15a and the vertical bars 15b, and the positive electrode current collecting ear 11A are made of, for example, lead or a lead alloy, and are added to the lead alloy. Is not limited, and known ones can be used. In particular, when a predetermined amount of Ca, Sn, Al, or Ag is added, the mechanical strength and corrosion resistance of the positive electrode grid 1 can be improved, which is more preferable in suppressing deformation due to growth.

  In the positive electrode grid 1 described above, for example, Ca is 0.02 to 0.08 mass%, Sn is 0.4 to 2.5 mass%, Al is 0.005 to 0.04 mass%, and Ag is 0.001. -0.0049 mass%, and the balance is formed from the lead alloy which consists of Pb and an unavoidable impurity.

  When the component elements of Ca, Sn, Al, and Ag are added within a specific range, it is possible to improve both the corrosion resistance and the mechanical strength of the resulting lead alloy. The addition of Ca improves the mechanical strength of the positive electrode grid body 1. If the amount of Ca is less than 0.02% by mass, the effect is small, and if it exceeds 0.08% by mass, the corrosion resistance may decrease. The addition of Sn improves the flowability of the molten lead alloy and improves the mechanical strength of the positive grid 1. If the amount of Sn is less than 0.4% by mass, the effect is small, and if it exceeds 2.5% by mass, the corrosion resistance may be lowered. The addition of Al prevents Ca loss due to the oxidation of the molten metal, and further improves the mechanical strength of the positive electrode grid 1. If the added amount of Al is less than 0.005% by mass, the effect is small, and if it exceeds 0.04% by mass, Al tends to precipitate as dross. The addition of Ag improves the mechanical strength, and in particular improves the creep resistance at high temperatures. If the addition amount of Ag is less than 0.001% by mass, the effect is small, and if it exceeds 0.0049% by mass, an increase in the effect due to the increase in the addition amount cannot be expected.

  The positive electrode grid body 1 can be produced, for example, by cutting a punched grid body or an expanded grid body of a rolled plate made of lead or a lead alloy, or a rolled plate by a discharge wire cut method or the like. Further, it may be produced as a cast lattice body by a book mold method or the like. In particular, the growth of the positive electrode grid 1 is likely to occur in a grid formed from a rolled plate in which crystal grains containing lead or a lead alloy are oriented. Therefore, the effect of suppressing the growth is a punched grid, an expanded grid, or a discharge. In the case of a lattice produced from a rolled plate by a wire cut method or the like, it is remarkably obtained.

  Hereinafter, the positive electrode grid body 1 according to another embodiment will be described with reference to the drawings. In addition, about the component same as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

<Second Embodiment>
FIG. 2 is a plan view showing the positive electrode grid body 1 according to the second embodiment. In addition to the configuration described in the first embodiment, the positive electrode lattice body 1 has a second vertical frame from the center side of the inner bone toward the first vertical frame bone 14a and from the center side of the inner bone. A plurality of vertical bars 15b are arranged so that the interval is gradually reduced toward the bone 14b side. For this reason, the area of the plurality of openings 16 in plan view is from the center side of the inner bone toward the first longitudinal frame bone 14a and from the center side of the inner bone to the second longitudinal frame bone 14b side. And become smaller step by step.

  The positive electrode grid body 1 according to the second embodiment has the same effects as those of the first embodiment. The stress generated by the expansion and contraction of the positive electrode active material in the positive electrode lattice body 1 is propagated from the center side of the inner bone of the positive electrode lattice body 1 toward the frame bone side. Further, in the lateral direction X of the positive grid 1, the lateral direction of the positive grid 1 is reduced by gradually reducing the area in plan view of the plurality of openings 16 from the central side of the inner bone toward the frame. The mechanical strength at X can be improved. As a result, according to the positive electrode grid body 1 according to the second embodiment, the growth of the positive electrode grid body 1 in the lateral direction X and the peeling or dropping of the positive electrode active material can be more effectively prevented.

<Third Embodiment>
FIGS. 3A and 3B are enlarged plan views showing the openings 16 included in the positive electrode grid body 1 according to the third embodiment. As shown in FIG. 3A, rounded corners R1 are formed at the four corners of the plurality of openings 16 formed in the positive electrode grid body 1 in plan view. The magnitude of the roundness R1 may be defined by, for example, the radius of curvature of the roundness R1.

  In addition, among the plurality of openings 16 adjacent to the frame bone, at least the four corners in plan view of the openings 16 located at the four corners of the frame bone are larger than the openings 16 located outside the four corners of the frame bone. At least one round R is provided. In the opening 16 located at the four corners of the frame bone, the size of the roundness R at the corner closest to the corner of the frame bone in the opening 16 is maximized. FIG. 3B shows an opening 16 disposed in the upper left corner defined by the first horizontal frame bone 13a and the first vertical frame bone 14a in the positive electrode grid body 1. In the opening 16 arranged at the upper left corner of the frame bone, the roundness of the upper left corner closest to the corner of the frame bone is indicated as R2, and the roundness of the other three corners in the opening 16 is indicated as R1. The size of the roundness R1, R2 is defined by, for example, the radius of curvature of the roundness R, and the roundness R2 is larger than the roundness R1.

  The openings 16 arranged at the other three corners of the frame bone are also provided with a large roundness R2 at the corner closest to the corner of the frame bone, as in FIG. Except for the openings 16 arranged at the four corners of the frame bone, small roundness R1 is provided at the four corners in the opening 16 as in FIG.

  As described above, in the positive electrode grid body 1 according to the third embodiment, as shown in FIG. 3A, the round holes R1 are formed at the four corners when the opening 16 is viewed in plan view, whereby the positive electrode to the opening 16 is formed. Since the filling property of the active material is improved and the unfilled region is reduced, the adhesion between the positive electrode grid body 1 and the positive electrode active material can be improved. Further, since the mechanical strength of the four corners in the opening 16 is improved, the positive grid 1 can be prevented from growing, and an internal short circuit caused by contact between the positive electrode plate and a part of the negative electrode such as the negative electrode plate or the negative electrode strap, It is possible to prevent the positive electrode active material from peeling or dropping and the accompanying accelerated growth.

  Further, in the positive electrode grid body 1 shown in FIG. 3B, among the plurality of openings 16, the positive electrode active material is selectively removed at the four corners in the openings 16 arranged at the four corners of the frame bone where the positive electrode active material is easily peeled off or dropped off. A large round R2 is provided. For this reason, peeling of the positive electrode active material from the positive electrode grid body 1 or growth of the positive electrode grid body 1 and growth of the positive electrode grid body 1 can be more effectively prevented without causing an unnecessary increase in the weight of the positive electrode grid body 1.

  Note that the roundness R1 provided in the plurality of openings 16 is not limited to the example shown in FIG. 3A, and the arrangement and size thereof are appropriately selected according to the ease with which the positive electrode active material can be peeled off or dropped off. May be. Further, it has been described that the size of the roundness R1 can be defined by the radius of curvature, but the roundness R is not limited to a circular arc. For example, it may be a polygon close to an arc. The size of the roundness R1 may be defined by, for example, the ratio of the area change due to the roundness R1 as compared to the case where the opening 16 is rectangular.

  The roundness R1, R2 provided in the plurality of openings 16 is not limited to the example shown in FIG. 3B, and the arrangement and size thereof are appropriately selected according to the ease of peeling or dropping off of the positive electrode active material. May be. Further, two or more types of roundness R may be provided at the four corners in the opening 16. For example, among the four corners in the opening 16, the roundness R at one corner and the remaining three corners are made different from each other. Of the four corners in the opening 16, the rounding R at the two corners and the two corners are made different from each other. Among the four corners, the roundness R at all corners is made different from each other, the rounding R at the two corners or three corners among the four corners in the opening 16 is made different from each other, and the rounding R is not provided at the remaining one corner or the two corners. You may make it the form. You may make it the form which arrange | positions the opening part 16 which all four corners do not have the roundness R in a part of inner bone. Although it has been described that the size of the roundness R1 or R2 can be defined by the radius of curvature, the roundness R1 or R2 is not limited to a circular arc. For example, it may be a polygon close to an arc. Furthermore, the size of the roundness R1 or R2 may be defined by a method of how much the area is reduced by the roundness R1 or R2 as compared with the case where the opening 16 is rectangular, for example.

<Fourth Embodiment>
FIGS. 4A and 4B are enlarged plan views showing the openings 16 included in the positive electrode grid body 1 according to the fourth embodiment. The positive electrode grid body 1 according to the fourth embodiment has the same configuration as that of the third embodiment except that the size of the roundness R provided at each of the four corners of the plurality of openings 16 is changed.

  In FIG. 4A, in the opening 16 disposed adjacent to the first lateral frame bone 13a, roundness R3 is provided at two corners adjacent to the first lateral frame bone 13a. Roundness R1 is provided at the two corners.

  FIG. 4B shows the opening 16 disposed in the upper left corner defined by the first horizontal frame bone 13a and the first vertical frame bone 14a in the positive electrode grid body 1. The opening 16 arranged at the upper left corner of the frame bone has a round R2 at the upper left corner closest to the corner of the frame bone, a round R1 at the corner opposite the round R2, and rounds at the other two corners. R3 is provided. The sizes of the roundness R1 to R3 are defined by, for example, the radius of curvature of the roundness R, and increase in the order of R1, R3, and R2.

  The opening 16 not adjacent to the frame bone has the same configuration as that shown in FIG. That is, roundness R1 is provided at four corners not adjacent to the frame bone.

  Although not shown, the openings 16 arranged at the other three corners of the positive electrode grid body 1 also have the same configuration as that shown in FIG. That is, the four openings arranged at the four corners of the positive grid 1 are round R2 at the corner closest to the corner of the frame bone, round R1 at the corner opposite to the round R2, and at the other two corners. A roundness R3 is provided.

  In the positive electrode grid body 1 according to the fourth embodiment, the same effects as those of the third embodiment can be obtained. In the positive electrode grid body 1, the positive electrode active material is easily peeled off or dropped off at a plurality of openings 16 disposed adjacent to the frame bone, particularly at the openings 16 located at the four corners of the frame bone. Therefore, in the positive electrode grid body 1 according to the fourth embodiment, the maximum roundness R2 is provided at the corner closest to the corner of the frame bone in the openings 16 located at the four corners of the frame bone. 4 (a) and 4 (b), a relatively large round R3 is also provided at the corner of the opening 16 adjacent to the frame bone. According to such a configuration, the adhesion of the positive electrode active material to the positive electrode grid body 1 is further improved as compared with the third embodiment, and the positive electrode active material is peeled off or dropped from the positive electrode grid body 1, and the positive electrode grid body. The internal short circuit accompanying the growth of 1 can be more effectively prevented.

<Fifth Embodiment>
FIG. 5 is an enlarged plan view showing a part of the positive electrode grid body 1 according to the fifth embodiment. The positive electrode grid body 1 according to the fifth embodiment includes one opening 16 corresponding to a position immediately below the negative electrode current collector ear 11B among the plurality of openings 16 adjacent to the first horizontal frame bone 13a, that is, the positive electrode plate. And the negative electrode plate are stacked via a separator to form a group of electrode plates, and when the electrode plate group is seen through in the stacking direction, straight lines are respectively suspended from the both ends of the negative electrode current collector ear 11B on the positive electrode grid 1 An auxiliary crosspiece 17 extending in the direction in which the first vertical frame bone 14a and the second vertical frame bone 14b extend, that is, the vertical direction Y is disposed in the opening 16 that overlaps at least partly with the enclosed region, and the opening The configuration is the same as that of the first embodiment except that 16 is divided into two. The area of the opening 16 divided by the auxiliary bar 17 in a plan view is about ½ of the area of the other adjacent opening 16.

  In the positive electrode grid body 1 according to the fifth embodiment, the same effects as those of the positive electrode grid body 1 according to the first embodiment can be obtained. When growth toward the upper side occurs in the positive electrode grid body 1, the first horizontal frame bone 13 a is one of the negative electrode current collector ear 11 </ b> B located on the upper side of the negative electrode grid body facing the positive electrode grid body 1 or the negative electrode such as the negative electrode strap. There is a risk that the lead-acid battery will reach the end of its life due to contact with the part and internal short circuit.

  As shown in FIG. 5, among the plurality of openings 16 adjacent to the first horizontal frame bone 13a, auxiliary bars 17 extending in the vertical direction Y are arranged in the openings 16 corresponding directly below the negative electrode current collector ear 11B. As a result, the area of the opening 16 in this region is reduced, and the number of inner bones in the positive electrode grid body 1 is relatively increased, so that the mechanical strength of the positive electrode grid body 1 at that location increases. As a result, the adhesion between the positive electrode grid 1 and the positive electrode active material is improved in the opening 16 where the auxiliary bars 17 are arranged, and the positive electrode grid 1 is accelerated by peeling or dropping off of the positive electrode active material. Can suppress growth. In addition, since the mechanical strength of the positive electrode grid body 1 increases in the opening 16 where the auxiliary bars 17 are arranged, the growth toward the upper side of the positive electrode grid body 1 can be suppressed, and an internal short circuit due to contact between the positive electrode and the negative electrode can be prevented. It can be effectively suppressed.

  The auxiliary bar 17 is not limited to the one that divides the opening 16 in the vertical direction, and the same effect can be obtained even if the auxiliary bar 17 is divided into a horizontal direction, an oblique direction, a cross, and the like. Further, the auxiliary crosspiece 17 may be one that does not divide the opening 16. For example, the auxiliary crosspiece 17 reduces the area of the opening 16 by partially increasing the cross-sectional area of the frame bone or the inner bone of the part. However, the same effect can be obtained.

<Sixth Embodiment>
FIG. 6 is an enlarged plan view showing a part of the positive electrode grid body 1 according to the sixth embodiment. The positive electrode grid body 1 according to the sixth exemplary embodiment has a first opening in two openings 16 corresponding to a position immediately below the negative electrode current collector ear 11B among the plurality of openings 16 adjacent to the first lateral frame bone 13a. Fifth implementation except that auxiliary bars 17 extending in the direction in which the vertical frame bone 14a and the second vertical frame bone 14b extend, i.e., in the vertical direction Y are respectively arranged, and the two openings 16 are divided into two respectively. It has the same configuration as the form. As shown in FIG. 6, the auxiliary crosspiece 17 has an opening 16 disposed adjacent to the first horizontal frame bone 13 a corresponding to a position immediately below the negative electrode current collecting ear 11 </ b> B according to the necessity of reinforcement of the positive electrode grid 1. A plurality may be arranged. The area in plan view of the opening 16 divided by the auxiliary bar 17 is about ½ of the area of the other adjacent opening 16.

  Also in the positive electrode grid body 1 according to the sixth embodiment, the same effect as in the fifth embodiment can be obtained. As in the sixth embodiment, by appropriately arranging a plurality of auxiliary bars 17 at positions corresponding to directly below the negative electrode current collector ear 11B, growth toward the upper side of the positive electrode grid body 1 can be suppressed, and the positive electrode An internal short circuit due to contact with the negative electrode can be more effectively suppressed.

<Seventh Embodiment>
FIG. 7 is an enlarged plan view showing a part of the positive electrode grid body 1 according to the seventh embodiment. The positive electrode grid body 1 according to the seventh embodiment includes not only the opening 16 corresponding to a position immediately below the negative electrode current collector ear 11B provided on the negative electrode plate of the lead storage battery, but also the negative electrode strap to which the negative electrode current collector ear 11B is connected. Opening 16 corresponding directly below 12B, that is, a positive electrode plate and a negative electrode plate are laminated via a separator to form an electrode plate group, and when the electrode plate group is seen through in the stacking direction, from both ends of the negative electrode strap 12B, respectively. The structure is the same as that of the fifth embodiment, except that an auxiliary bar 17 is disposed in the opening 16 that overlaps at least partly with a region surrounded by a straight line suspended on the positive electrode grid 1. The area of the opening 16 divided by the auxiliary bar 17 is about ½ of the area of the other adjacent openings 16.

  Also in the positive electrode grid body 1 according to the seventh embodiment, the same effect as in the fifth embodiment can be obtained. As in the seventh embodiment, by arranging the plurality of auxiliary bars 17 in the opening 16 corresponding to the position immediately below the negative electrode strap 12B, the growth toward the upper side of the positive electrode lattice body 1 can be suppressed, An internal short circuit due to contact with the negative electrode can be more effectively suppressed.

<Eighth Embodiment>
Hereinafter, the structure of the lead acid battery according to the eighth embodiment will be described. The configuration of the lead storage battery according to the eighth embodiment is not particularly limited except that at least the positive electrode grid plate according to any one of the first to seventh embodiments is used for the positive electrode plate.

  Although not shown in detail, the lead storage battery has a monoblock structure in which electrode plates are housed in cell chambers divided into six by partition walls in a battery case made of a bottomed rectangular tube-shaped resin. In the electrode plate group, a positive electrode plate and a negative electrode plate inserted in a bag-like separator are alternately laminated via a glass fiber retainer mat or the like. As an example, the electrode plate group includes seven positive electrode plates and eight negative electrode plates.

  The positive electrode plate is manufactured by filling the positive electrode active material prepared according to a conventional method into the positive electrode grid body 1 of any of the first to seventh embodiments described above, and aging and drying according to a conventional method. The negative electrode plate is manufactured by filling a negative electrode grid body with a negative electrode active material prepared according to a conventional method, and aging and drying according to a conventional method. The structure of the negative electrode grid body has, for example, a radial shape in which the negative electrode current collector ear 11B is disposed at a position symmetrical to the positive electrode grid body described above. In the electrode plate group, when the positive electrode current collecting ear 11A of the positive electrode plate and the negative electrode current collecting ear 11B of the negative electrode plate are seen through in the stacking direction, the center lines in the longitudinal direction of the first lateral frame bone 13a are mutually connected. They are arranged at symmetrical positions with respect to each other. The electrode plate groups are respectively arranged in the six cell chambers of the battery case with the positive electrode collector ear 11A and the negative electrode collector ear 11B facing upward. The negative electrode current collecting ears 11B of the plurality of negative electrode plates are electrically connected and fixed by a common negative electrode strap 12B for each electrode plate group. Similarly, the positive electrode current collecting ears 11A of the plurality of positive electrode plates are electrically connected and fixed by a common positive electrode strap for each electrode plate group. Furthermore, the positive electrode strap and the negative electrode strap 12B are connected to an inter-cell connection member that penetrates through a partition wall between cells and connects the electrode plate groups in series, or a pole column that extends upward.

  The battery case in which the electrode plate group is accommodated has a lid fitted into the opening 16 thereof. A hollow positive electrode terminal and a negative electrode terminal are provided at predetermined positions of the lid. The positive strap and the negative strap 12B are connected and fixed to the positive terminal and the negative terminal via the positive pole and the negative pole. An electrolyte composed of a sulfuric acid aqueous solution (dilute sulfuric acid) with a specific gravity of 1.240 is injected into the battery case through a column liquid port provided on the lid, and a battery is formed to supply voltage from between the positive electrode terminal and the negative electrode terminal. It becomes possible.

  As described above, the lead storage battery according to the eighth embodiment using the positive electrode grid body according to any of the first to seventh embodiments has an internal short circuit and battery capacity due to the growth of the positive electrode grid body. Decrease is prevented and life is improved.

  In each of the first to eighth embodiments, the lateral frame bones 13a and 13b of the positive electrode grid body and the plurality of horizontal beams 15a are arranged in parallel, and the horizontal frame bones 13a and 13b and the plurality of horizontal beams 15a are arranged. Although the example arrange | positioned at right angle with respect to the vertical frame bones 14a and 14b and the several vertical crosspiece 15b was demonstrated, it is not limited to this. For example, the horizontal frame bones 13a and 13b and the plurality of horizontal bars 15a may not be arranged in parallel to each other, and may be arranged at a desired angle with each other. Similarly, the vertical frame bones 14a and 14b and the plurality of vertical bars 15b may not be arranged in parallel with each other, and may be arranged at a desired angle with each other. Further, the horizontal frame bones 13a and 13b and the vertical frame bones 14a and 14b constituting the frame bone, and the plurality of horizontal beams 15a and the vertical beam 15b constituting the inner bone have been described as an example. However, it is not limited to this, it may be a curved line or a polygonal line, and may have a branch. Further, the example in which the plurality of horizontal bars 15a and the plurality of vertical bars 15b have the same thickness is arranged at a constant interval has been described. May be changed as appropriate. The same applies to the auxiliary bar 17.

  In each embodiment, an example in which the shape of the plurality of openings 16 is a rectangular shape or a rectangular shape with rounded corners R at four corners has been described, but the present invention is not limited to this. The shape of the plurality of openings 16 may be other polygonal shapes or circular shapes, for example.

  In each embodiment, as a method of reducing the area of the opening 16 of the positive electrode grid body, the intervals at which the plurality of horizontal beams 15a and the vertical beams 15b constituting the frame bone and the inner bone defining the opening 16 are arranged. Although what narrowed was demonstrated, it is not limited to this. In order to reduce the area of the opening 16, for example, roundness R may be provided at the four corners of the rectangular opening 16. By appropriately changing the radius of curvature of the roundness R, the area of the opening 16 can be adjusted. Or in order to make the area of the opening part 16 small, you may thicken only the part of the thickness of the several horizontal crosspiece 15a and the vertical crosspiece 15b which comprise the frame bone and inner bone which define the said opening part 16. As shown in FIG. Moreover, you may combine suitably the method of reducing the area of the opening part 16 mentioned above.

  Furthermore, in each embodiment, although the positive electrode current collection ear | edge 11A demonstrated the example which is a rectangular plate shape, it is not limited to this. The shape of the positive electrode current collecting ear 11A may be appropriately changed in consideration of the current collecting performance and strength, and may be, for example, a fan shape, a triangle, or a rectangular shape with rounded corners R. Further, the width of the positive electrode current collecting ear 11A may be appropriately changed. The same applies to the negative electrode current collecting ear 11B.

  In addition, the structure of the positive electrode grid body 1 demonstrated in the 1st-7th embodiment can be combined mutually. The embodiments of the present invention have been specifically described above, but the present invention is not limited to these embodiments and examples, and various modifications based on the technical idea of the present invention are possible. .

  DESCRIPTION OF SYMBOLS 1 ... Positive electrode grid, 13a ... 1st horizontal frame bone, 13b ... 2nd horizontal frame bone, 14a ... 1st vertical frame bone, 14b ... 2nd vertical frame bone, 15a ... Horizontal beam, 15b ... Vertical Crosspiece, 16 ... opening, R1, R2 ... roundness R, 17 ... auxiliary crosspiece, 11A ... positive electrode current collector ear, 11B ... negative electrode current collector ear, 12B ... negative electrode strap

Claims (9)

A positive electrode grid for a lead-acid battery,
A rectangular frame-shaped frame bone comprising a first horizontal frame bone and a second horizontal frame bone extending in the horizontal direction, and a first vertical frame bone and a second vertical frame bone extending in the vertical direction;
An inner bone comprising a plurality of horizontal bars and vertical bars arranged in a lattice connected to the frame bone;
A plurality of openings defined by a region surrounded by the frame bone and the plurality of horizontal beams and the vertical beam, and a region surrounded by the plurality of horizontal beams and the vertical beam; and the second A positive electrode current collecting ear connected to the first horizontal frame bone located on the vertical frame bone side;
With
The average area in plan view of the plurality of openings adjacent to the first vertical frame bone and the second vertical frame bone is the average area in plan view of the remaining openings excluding the plurality of openings. And the area of the plurality of openings in plan view is the same as the second horizontal frame bone when compared on the same vertical line that cuts the first horizontal frame bone and the second horizontal frame bone vertically. A positive electrode grid for a lead storage battery, wherein the positive electrode grid for the lead storage battery decreases in a stepwise manner from the lateral frame bone side toward the first lateral frame bone side.   An area of the plurality of openings in plan view is gradually reduced from the center side of the inner bone toward the first longitudinal frame bone side, and the second longitudinal frame bone from the center side of the inner bone. The positive electrode lattice body for a lead storage battery according to claim 1, wherein the positive electrode lattice body becomes smaller stepwise toward the side.   In a plurality of openings that are vertically continuous from the second lateral frame bone side toward the first lateral frame bone side, the upper opening portion relative to an area obtained by planarly viewing the lower opening portion is viewed in plan view. The positive electrode grid for a lead storage battery according to claim 1 or 2, wherein the ratio of the area is 0.85 times or more and not exceeding 0.99 times.   Of the plurality of openings adjacent to the first lateral frame bone, it corresponds directly below a negative electrode current collection ear provided on a negative electrode plate of a lead storage battery or directly below a negative electrode strap to which the negative electrode current collection ear is connected. The said opening part is divided | segmented by the auxiliary | assistant crosspiece extended in the same direction as the direction where the said 1st vertical frame bone and the said 2nd vertical frame bone are extended. The positive electrode grid for lead-acid batteries described in 1.   4. The positive electrode grid body for a lead storage battery according to claim 1, wherein the four corners of the plurality of openings in plan view have roundness R. 6.   Of the plurality of openings adjacent to the frame bone, at least the four corners in plan view of the openings located at the four corners of the frame bone are larger than the openings located at other than the four corners of the frame bone. At least one roundness R is provided, and the size of the roundness R at the corner closest to the corner of the frame bone in the opening portion is maximized in the opening portions located at the four corners of the frame bone. The positive electrode grid for a lead storage battery according to claim 5.   It is a punching grid body of the rolling plate of lead or a lead alloy, The positive electrode grid body for lead acid batteries of any one of Claims 1-6 characterized by the above-mentioned.   In the lead alloy, Ca is 0.02 to 0.08 mass%, Sn is 0.4 to 2.5 mass%, Al is 0.005 to 0.04 mass%, and Ag is 0.001 to 0.0049. 8. The positive electrode grid for a lead storage battery according to claim 7, wherein the positive electrode lattice body has a composition comprising mass% and the balance of Pb and inevitable impurities.   A lead-acid battery comprising the positive electrode grid for a lead-acid battery according to any one of claims 1 to 8.

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