JP2019153387A - Positive electrode lattice 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 growth of positive electrode lattice body.SOLUTION: A positive electrode lattice body for lead acid battery includes: rectangular frame shape frame bones having first and second crosswise frame bones, and first and second vertical frame bones extending in the lengthwise direction; inner bones arranged in the bone frames, and having multiple horizontal rails and muntins provided in lattice while being connected with the frame bones; multiple openings provided as a region surrounded by the frame bones and the multiple horizontal rails and muntins, and a region surrounded by the multiple horizontal rails and the muntins; and a positive electrode collector lug. Out of the multiple openings, multiple openings adjacent to the second crosswise frame bones are a first opening group, some of the multiple muntins providing the first opening group are placed while being deviated crosswise for the muntins providing the multiple openings adjacent to the first opening group in the lengthwise direction, and the area of the multiple openings, excepting the first opening group, decreases gradually from the horizontal rail side toward the first horizontal rail side, when comparing on the same perpendicular traversing the first and second crosswise frame bones.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. Since the ISS vehicle can suppress fuel consumption due to idling when the vehicle is stopped due to a signal or the like, the fuel efficiency can be improved and the amount of exhaust gas can be reduced.

  It is known that the lead storage battery mounted on the ISS vehicle as described above 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., the lead storage battery is used in a deeply discharged state in order to supply power 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-acid battery due to repeated discharges for restarting the engine at the time of start-up 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 due to corrosion of the positive electrode lattice body. Such deformation of the positive electrode lattice is called growth. When 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. Moreover, the growth of the positive electrode lattice causes peeling or dropping of the positive electrode active material, which causes an early capacity decrease. Due to the circumstances described above, 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 lead-acid batteries is caused by PbO _x (x: 1 to 2) or PbSO reacting with sulfate ions contained mainly in the electrolyte or active material by charge / discharge of lead or lead alloy forming the positive electrode grid. _This results from an oxidation reaction that changes to a corrosion reaction product having a multilayer structure composed of ₄ etc. 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 plate.

  The electrode plate group of the lead-acid battery is fixed to the upper side of the lid or battery case by a pole column provided to extend upward from the strap and the connection member between the cells, so when the 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 positive electrode lattice body grows, the heel part is crushed and absorbed when the growth occurs in the positive electrode lattice body, so the upward extension of the positive electrode lattice 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-acid battery having a structure in which the positive electrode plate is suspended and the lower side of the positive electrode plate does not contact 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 Document 4 and Patent Document 5, as a method for suppressing contact between the positive electrode plate and the negative electrode plate due to growth, lead having a portion with low mechanical strength such as a notch or a constricted portion in a predetermined portion of the positive electrode grid body A storage battery is disclosed. In this way, by forming a portion with low mechanical strength in a part of the positive electrode lattice, when growth occurs, the portion with low mechanical strength is preferentially broken or deformed, 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, in a positive electrode lattice body, 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 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 to 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 also 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 center of the positive electrode grid, the expansion and contraction of the positive electrode active material is not necessarily maximized when the current density distribution is considered. It could not be said to be an efficient prevention method, 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.

  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 problems, according to one embodiment, a first horizontal frame bone and a second horizontal frame bone extending in the lateral direction, and a first vertical frame bone and a second vertical frame extending in the vertical direction are provided. A rectangular frame-shaped frame bone including a frame bone; an inner bone including a plurality of horizontal bars and vertical bars arranged in a lattice and connected to the frame bone; and a frame frame and a plurality of horizontal frames A region surrounded by the crosspieces and the vertical crosspieces, and a plurality of openings defined as a region surrounded by the plurality of horizontal crosspieces and the vertical crosspieces; and a first horizontal frame bone located on the second vertical frame bone side A plurality of openings adjacent to the second lateral frame bone are defined as a first opening group, and the first opening group is defined. At least a portion of the plurality of vertical bars that are lateral to the vertical bars that define the plurality of openings adjacent to the first opening group in the vertical direction. The areas of the plurality of openings excluding the first opening group, as viewed in plan, are arranged in the same direction to cut the first horizontal frame bone and the second horizontal frame bone vertically. When compared on a line, there is provided a positive electrode lattice body for a lead storage battery, characterized in that it gradually decreases from the second lateral frame bone side toward the first lateral frame bone side.

  According to another embodiment, there is provided a lead storage battery comprising the positive electrode grid for a lead storage battery described above.

  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 for lead acid batteries and a lead acid battery which can improve the lifetime of a lead acid battery can be provided.

It is a top view of the positive electrode grid concerning a 1st embodiment. It is a perspective view which shows the lead acid battery which concerns on 2nd Embodiment.

<First Embodiment>
FIG. 1 is a plan view of a positive electrode grid body 1 for a lead storage battery according to the first 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.

  The first horizontal frame bone 13a located on the second vertical frame bone 14b side is connected to a positive electrode current collecting ear 11A for connecting the positive electrode grid body 1 to the outside. 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 horizontal frame bones 13a are arranged so as to be shifted from each other in the length direction, and are arranged so that only the current collecting ears of the same polarity overlap each other. In particular, in the example shown in FIG. 1, the positive electrode current collector ear 11 </ b> A and the negative electrode current collector ear 11 </ b> B are arranged at positions symmetrical to each other with respect to the center line in the horizontal direction X of the positive electrode grid 1.

  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. 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. The plurality of horizontal rails 15a are separated from each other in, for example, the longitudinal direction Y and have their respective axes parallel to each other from the second horizontal frame bone 13b (that is, the lower side in FIG. 1) to the first horizontal frame bone 13a (that is, , The intervals are narrowed stepwise (upper side in FIG. 1). The plurality of vertical rails 15b are spaced apart from each other in the horizontal direction X, for example, and their axes are arranged in parallel. The plurality of vertical bars 15b and the plurality of horizontal bars 15a are arranged, for example, with their axes intersecting each other at right angles.

  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 beams 15a and vertical beams 15b, and a region surrounded by the plurality of horizontal beams 15a and vertical beams 15b. The In particular, among the plurality of openings 16, a plurality of openings 16 adjacent to the second lateral frame bone 13 b are defined as a first opening group 17. The area in plan view of the plurality of openings 16 excluding the first opening group 17 is arranged so that the intervals between the plurality of horizontal bars 15a become narrower from the lower side toward the upper side as described above. When the first horizontal frame bone 13a and the second horizontal frame bone 13b are compared on the same vertical line, the step is directed from the second horizontal frame bone 13b side to the first horizontal frame bone 13a side. Become smaller. That is, in the example shown in FIG. 1, the area of one opening 16 located on the same perpendicular from the upper side is smaller than the area of the opening 16 located on the same perpendicular to the y + 1th. Become. Here, the area of the plurality of openings 16 continuously arranged in the vertical direction on the same vertical line is the second horizontal frame bone from the second horizontal frame bone 13b side toward the first horizontal frame bone 13a side. It is preferable to reduce the size stepwise within a range not exceeding 0.85 times and 0.99 times the area of the opening 16 on the 13b side. In addition, the average area of the plurality of openings 16 adjacent to the first vertical frame bone 14 a and the second vertical frame bone 14 b in plan view is the average of the remaining plurality of openings 16 excluding the plurality of openings 16. It is preferable to make it smaller than the average area.

  In addition, at least a part of the plurality of vertical bars 15b ′ defining the first opening group 17 of the positive electrode grid body 1 defines the plurality of opening parts 16 adjacent to the first opening group 17 in the vertical direction Y. The plurality of vertical bars 15b are shifted in the horizontal direction X. That is, in this configuration, the vertical beam 15b is connected to the horizontal beam 15a defining the upper side of the first opening group 17 at least partially in an inverted T shape.

  Each of the plurality of openings 16 in plan view has a quadrangle, for example, a rectangular shape or a trapezoidal shape. In addition, the shape of the plurality of openings 16 in plan view is not limited to the above. For example, when an oblique reinforcing bar is inserted, the shape is rounded at other corners such as a rectangle or a triangle, a circle, or four corners of the rectangle. It may be formed in the shape provided with.

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

  As explained in the background art, the electrode plate group including the positive electrode plate of the lead-acid battery has a lid or a battery case on the upper side via the positive electrode current collecting ear 11A connected to the right side of the first lateral frame bone 13a. It is fixed at the top. On the other hand, on the lower side, the electrode plate group is in contact with the bottom surface of the battery case supporting the electrode plate group or a flange provided on the bottom surface. Therefore, the positive electrode grid body 1 is less likely to grow on the upper right side fixed by the positive electrode current collector ear 11A and the lower side in contact with the battery case because expansion in the direction is limited.

  However, in the positive electrode grid body 1, growth is likely to occur at the left upper side that is not fixed by the positive electrode current collecting ear 11 </ b> A and the portions that are not in contact with the left and right battery cases. In particular, there is a possibility that the upper end of the positive electrode plate contacts a part of a negative electrode such as a negative electrode strap 12B (described later) due to the growth of the positive electrode grid 1 in the upper left direction, thereby causing an internal short circuit.

  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 the positive electrode grid body 1 according to the first embodiment, the areas of the plurality of openings 16 excluding the first opening group 17 in plan view are the first horizontal frame bone 13a and the second horizontal frame bone 13b. Are compared with each other on the same vertical line that cuts vertically, and gradually decreases from the second lateral frame bone 13b side toward the first lateral frame bone 13a side. In other words, in the positive electrode grid body 1 according to the first embodiment, an opening having a smaller area is arranged on the first lateral frame bone 13a side (upper side).

  As described above, in the openings 16 having a small area on the upper side of the positive electrode grid body 1, 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 body 1 It increases compared with the opening 16 having a large area located on the lower side. 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 said 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 is more desirable in preventing the above accelerated growth. When the area ratio exceeds 0.99 times, the area difference between the upper side and the lower side of the positive electrode grid body 1 is small, so that the effect of selectively increasing the reinforcement on the upper side of the positive electrode grid body 1 is reduced. . When the area ratio is less than 0.85 times, filling of the positive electrode active material is improved by reducing the opening 16 on the upper side of the positive electrode grid 1, but the lower opening 16 is relatively large. As a result, the output characteristics and the retention of the positive electrode active material may be reduced.

  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 remainder excluding the plurality of openings 16 It is preferable to make it smaller than the average area of the plurality of 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 positive electrode active material filled in the plurality of openings 16 has a ratio of being in contact with a certain area of the positive electrode grid 1 to the other plurality. This is larger than the positive electrode active material filled in the opening 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.

  Furthermore, in the positive electrode grid body 1 according to the first embodiment, at least a part of the plurality of vertical bars 15b ′ defining the first opening group 17 is adjacent to the first opening group 17 in the vertical direction Y. The plurality of vertical bars 15b defining the plurality of openings 16 are arranged so as to be shifted in the lateral direction X.

  Since the positive electrode grid body 1 according to the first embodiment has such a configuration, even when growth occurs and the plurality of vertical bars 15b extend downward, the vertical bars 15b and the first At the intersection where the horizontal beam 15a defining the upper side of the opening group 17 is connected in an inverted T shape, the horizontal beam 15a is bent downward with the adjacent vertical beam 15b 'as a fulcrum and absorbs displacement due to the extension. it can. As a result, since the downward extension of the plurality of vertical bars 15b is absorbed by the inner bones including the horizontal bars 15a and the vertical bars 15b, the growth toward the lower side of the entire positive electrode grid body 1 can be suppressed. As described in the background art, since the growth generated downward by the bottom surface of the battery case supporting the electrode plate group or the flange provided on the bottom surface turns upward, the upper end of the positive electrode plate is the negative electrode strap 12B or the like. There is a risk of causing an internal short circuit by contacting a part. According to this configuration, the upward growth can be prevented by absorbing the downward growth by the inner bone including the horizontal rail 15a and the vertical rail 15b, and the upper end of the positive electrode plate and a part of the negative electrode such as the negative strap. Can prevent internal short circuit due to contact with.

  In the example shown in FIG. 1, all of the plurality of vertical bars 15 b ′ that define the first opening group 17 define a plurality of openings 16 adjacent to the first opening group 17 in the vertical direction Y. Although the example which has shifted | deviated and arrange | positioned in the horizontal direction X with respect to the vertical bar 15b to perform is demonstrated, it is not limited to this.

  In addition, “at least a part of the plurality of vertical bars 15b ′ defining the first opening group 17” includes a plurality of vertical bars 15b ′ positioned immediately below the positive electrode current collector ear 11A, and in the horizontal direction X. 50% or more, preferably 70% or more, of the plurality of vertical bars 15b ′ arranged.

  Furthermore, it is preferable to form the four corners in a plan view of the plurality of openings 16 formed in the positive electrode grid body 1 in a shape having roundness R. By doing in this way, the filling property of the positive electrode active material to the said opening part 16 can be improved. Moreover, in order to improve the mechanical strength of the four corners in the opening 16, it is possible to prevent the positive grid 1 from growing, and an internal short circuit due to 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.

  Therefore, according to 1st Embodiment, the internal short circuit resulting from the growth of the positive electrode grid 1 can be prevented, and the positive electrode grid for lead acid batteries and a lead acid battery which can improve the lifetime of a lead acid battery can be provided.

  Further, the frame bone constituting the positive grid 1, the inner bone including 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 integrally formed. The metal element added to the lead alloy is not limited, and a known element 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. 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. For this reason, the effect of suppressing the growth is remarkably obtained when applied to a punched lattice body, an expanded lattice body, or a lattice body manufactured from a rolled plate by a discharge wire cutting method or the like.

  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.

  In the example shown in FIG. 1, the horizontal frame bones 13 a and 13 b and the plurality of horizontal bars 15 a of the positive grid 1 are arranged in parallel, and the horizontal frame bones 13 a and 13 b and the plurality of horizontal bars 15 a are the vertical frame bones. Although the example arrange | positioned at right angle with respect to 14a, 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 an angle to 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. In addition, the horizontal frame bones 13a and 13b and the vertical frame bones 14a and 14b and the plurality of crosspieces constituting the frame bone have been described as being linear, but the present invention is not limited thereto, and is not limited to a curved shape or a broken line shape. It may also 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, but the present invention is not limited thereto, and the thickness and the arrangement interval are not limited thereto. May be changed as appropriate.

  Further, the opening 16 is not limited to the vertical direction, and the same applies to the auxiliary bars that divide into the horizontal direction, the diagonal direction, the cross, and the like.

  In the example shown in FIG. 1, as a method of reducing the area of the opening of the positive electrode grid body 1, the intervals at which the plurality of horizontal beams 15 a and the vertical beams 15 b 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.

  Moreover, although the example in which the positive electrode current collecting ear 11A has a rectangular plate shape has been described, the present invention is not limited thereto. 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. In the illustrated example, the positive electrode current collector ear 11A having the same width as the interval between the plurality of vertical bars 15b has been described. However, the present invention is not limited to this, and the width thereof may be changed as appropriate. The same applies to the negative electrode current collecting ear 11B.

<Second Embodiment>
FIG. 2 is a perspective view showing an electrode plate group 10 constituting a lead storage battery (not shown) according to the second embodiment. The lead acid battery according to the second embodiment includes an electrode plate group 10 including the positive electrode grid body 1 according to the first embodiment. The configuration of the lead storage battery according to the second embodiment is not particularly limited, except that at least the positive electrode grid body 1 according to the first embodiment is used for the positive electrode plate. As shown in FIG. 2, the lead acid battery is a lead acid battery having an electromotive force of 2 V composed of a single cell. The positive electrode plate P, the negative electrode plate N, dilute sulfuric acid as an electrolyte, separator S (glass fiber retainer mat, etc.) ), A battery case (not shown), a lid (not shown) and the like. For example, while the separator S is interposed between the positive electrode plate P and the negative electrode plate N, the positive electrode plates P and the negative electrode plates N are alternately stacked one by one, and the positive electrode current collector ears 11A and the negative electrode current collector ears 11B are stacked. These are connected with each other by a positive electrode strap 12A and a negative electrode strap 12B to constitute an electrode plate group 10. A positive electrode pole column 18A and a negative electrode column 18B extending upward are connected to the positive electrode strap 12A and the negative electrode strap 12B. The electrode plate group 10 is put into the battery case from the opening of the battery case, and a lid is fitted to the hollow positive electrode terminal (not shown) and negative electrode terminal (not shown) provided on the cover. Then, each positive electrode pole 18A and negative electrode pole 18B are inserted and welded. After injecting dilute sulfuric acid, which is an electrolytic solution, from a liquid injection port provided on the lid, chemical conversion is performed to complete a lead storage battery with an electromotive force of 2V.

  As described above in detail, according to the positive electrode grid body 1 and the lead storage battery according to the first and second embodiments, the positive electrode plate P and the negative electrode plate N or the negative electrode strap 12B caused by the growth of the positive electrode grid body 1 An internal short circuit due to contact with a part of the negative electrode can be prevented, the durability of the lead storage battery can be improved, and a longer life can be realized.

  In addition, although liquid type lead acid battery was illustrated as lead acid battery in 2nd Embodiment, control type lead acid battery may be sufficient.

  As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to these embodiment and Example, Various change based on the technical idea of this invention is possible. .

  DESCRIPTION OF SYMBOLS 1 ... Positive electrode grid body, 11A ... Positive electrode current collection ear, 11B ... Negative electrode current collection ear, 12A ... Positive electrode strap, 12B ... Negative electrode strap, 13a ... 1st horizontal frame bone, 13b ... 2nd horizontal frame bone, 14a ... 1st vertical frame bone, 14b ... 2nd vertical frame bone, 15a ... Horizontal beam, 15b, 15b '... Vertical beam, 16 ... Opening, 17 ... 1st opening group, 18A ... Positive electrode pole column, 18B ... Negative electrode pole, P ... Positive electrode plate, N ... Negative electrode plate, S ... Separator, 10 ... Pole plate group

Claims (7)

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 provided with a plurality of horizontal bars and vertical bars arranged in a lattice and connected to the frame bone;
A plurality of openings defined as 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 vertical A positive electrode current collecting ear connected to the first lateral frame bone located on the frame bone side;
With
Among the plurality of openings, the plurality of openings adjacent to the second lateral frame bone are set as a first opening group,
At least a part of the plurality of vertical bars defining the first opening group is in a lateral direction with respect to the vertical bars defining the plurality of openings adjacent to the first opening group in the vertical direction. Shifted,
The area in plan view of the plurality of openings excluding the first opening group is compared on the same vertical line that vertically cuts the first lateral frame bone and the second lateral frame bone, A positive electrode grid for a lead storage battery, wherein the positive electrode grid for a lead-acid battery decreases in a stepwise manner from the second lateral frame bone side toward the first lateral frame bone side.   When the first horizontal frame bone and the second horizontal frame bone are compared on the same vertical line, the first horizontal frame bone with respect to the area of the opening on the second horizontal frame bone side in plan view. 2. The positive electrode grid for a lead-acid battery according to claim 1, wherein the ratio of the area of the opening on the frame bone side in plan view is in a range not less than 0.85 times and not more than 0.99 times.   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. The positive electrode lattice body for a lead storage battery according to claim 1 or 2, wherein the positive electrode lattice body is smaller than the positive electrode lattice body.   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. 5.   5. The positive electrode grid for a lead storage battery according to claim 1, wherein the grid is a punched grid of a rolled plate of lead or a lead alloy.   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. The positive electrode lattice body for a lead storage battery according to claim 5, wherein the positive electrode lattice body has a composition comprising mass% and the balance being Pb and inevitable impurities.   A lead storage battery comprising the positive electrode grid for a lead storage battery according to any one of claims 1 to 6.

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