Lead storage battery

Abstract

Provided is a lead-acid battery in which a difference in formation efficiency between a positive electrode plate and a negative electrode plate is reduced by increasing the formation efficiency of the positive electrode plate, thereby reducing the formation charge required for formation to proceed sufficiently. The lead-acid battery comprises an electrode plate group and an electrolyte solution. The electrode plate group has a laminate comprising a plurality of positive electrode plates (10) and negative electrode plates (20) arranged alternately, and separators (30) arranged between the positive electrode plates and the negative electrode plates. The positive electrode plate (10) has a positive electrode current collector plate (101) and a positive electrode mixture (102) held in a lattice-shaped part (101a) of the positive electrode current collector plate (101). The negative electrode plate (20) has a negative electrode current collector plate (201) and a negative electrode mixture (202) held in a lattice-shaped part (201a) of the negative electrode current collector plate (201). The thickness of the positive electrode current collector plate (101) is smaller than the thickness of the negative electrode current collector plate (201).

Description

lead acid battery

[0001] This invention relates to a lead-acid battery.

[0002] A typical lead-acid battery, a liquid lead-acid battery, comprises a battery case with cell chambers, a group of electrode plates housed in the cell chambers, and an electrolyte injected into the cell chambers. The group of electrode plates has a laminate comprising a plurality of alternatingly arranged positive and negative electrode plates, and a separator placed between the positive and negative electrode plates. The positive electrode plate has a positive electrode current collector plate including a grid-like portion, positive electrode tabs protruding upward in the vertical direction from the battery case of the grid-like portion, and a positive electrode mixture (a mixture containing positive electrode active material) held in the grid-like portion. The negative electrode plate has a negative electrode current collector plate including a grid-like portion, negative electrode tabs protruding upward in the vertical direction from the battery case of the grid-like portion, and a negative electrode mixture held in the grid-like portion.

[0003] The positive electrode lugs are positioned offset to one side from the center in the width direction of the grid (a direction perpendicular to both the vertical direction of the battery case and the stacking direction of the laminate), and the negative electrode lugs are positioned offset to the other side from the center in the width direction of the grid. The electrode group further has positive electrode straps and negative electrode straps that connect the lugs of multiple positive and negative electrode plates, respectively. Dilute sulfuric acid is used as the electrolyte. Such liquid lead-acid batteries are widely used as automobile batteries and the like.

[0004] In the manufacture of liquid lead-acid batteries, a group of electrode plates, including a laminate made using a positive electrode packing plate (positive electrode plate before chemical formation) and a negative electrode packing plate (negative electrode plate before chemical formation), is placed in a cell chamber and subjected to a chemical formation process in which electricity is passed through it in dilute sulfuric acid. Through this chemical formation process, the positive electrode packing plate and negative electrode packing plate are converted into positive and negative electrode plates. Regarding the chemical formation process, in recent years, from the perspective of rising electricity costs and the environmental impact of carbon dioxide emissions, there has been a demand for reducing the amount of electricity used during chemical formation, i.e., improving the chemical formation efficiency. Furthermore, regarding the thickness of the positive electrode current collector plate and negative electrode current collector plate in conventional lead-acid batteries, as described in the example in Patent Document 1, the thickness of the positive electrode current collector plate is greater than the thickness of the negative electrode current collector plate.

[0005] Japanese Patent Publication No. 2001-068117

[0006] In typical lead-acid batteries, the positive electrode plate has a lower chemical conversion efficiency than the negative electrode plate. Furthermore, as mentioned above, in conventional lead-acid batteries, the positive electrode current collector plate is made thicker than the negative electrode current collector plate. In lead-acid batteries with such a configuration, the difference in chemical conversion efficiency between the positive and negative electrode plates becomes even larger, requiring a larger amount of electricity to sufficiently convert the positive electrode plate. The object of the present invention is to provide a lead-acid battery in which the difference in chemical conversion efficiency between the positive and negative electrode plates is reduced by increasing the chemical conversion efficiency of the positive electrode plate, thereby reducing the amount of electricity required for sufficient conversion.

[0007] A first aspect of the present invention for solving the above problems is a lead-acid battery having the following configurations (1) to (3): (1) A group of electrode plates and an electrolyte, the group of electrode plates having a laminate consisting of alternately arranged negative electrode plates and positive electrode plates, and a separator disposed between the negative electrode plate and the positive electrode plate. (2) The positive electrode plate has a positive electrode current collector plate and a positive electrode mixture held in a grid-like portion of the positive electrode current collector plate. The negative electrode plate has a negative electrode current collector plate and a negative electrode mixture held in a grid-like portion of the negative electrode current collector plate. (3) The thickness of the positive electrode current collector plate is smaller than the thickness of the negative electrode current collector plate.

[0008] A second aspect of the present invention is a lead-acid battery having the above configurations (1) and (2) and the following configurations (4) and (5). (4) The grid-like portion of the positive electrode current collector plate is formed by an outer frame and a plurality of parallel horizontal ribs and a plurality of vertical ribs intersecting the horizontal ribs arranged within the outer frame, and has a rectangular opening formed by two adjacent horizontal ribs and two adjacent vertical ribs. (5) The positive electrode packing plate, which is the positive electrode plate before chemical formation, has the unformed positive electrode mixture filled in the opening, and a layer made of the unformed positive electrode mixture is formed on at least one end face in the thickness direction of the grid-like portion, continuously with the filled unformed material, and is located inside the rectangle in a plan view, and the radius A (mm) of the largest circle that is tangent to two or more of the four sides constituting the rectangle and the thickness B (mm) of the layer of the positive electrode packing plate satisfy the following equation (1). √(A 2 +B ２ )≦5.1(mm)…(1)

[0009] In the second embodiment of the lead-acid battery, for example, the electrode plate group is housed together with the electrolyte in the cell chamber of the battery case, and the positive electrode filling plate is converted into the positive electrode plate by battery case formation, and the negative electrode filling plate, which is the negative electrode plate before formation, is converted into the negative electrode plate.

[0010] According to the present invention, by increasing the chemical conversion efficiency of the positive electrode plate, the difference in chemical conversion efficiency between the positive electrode plate and the negative electrode plate is reduced, and it is expected that a lead-acid battery will be provided in which the amount of chemical conversion electricity required to sufficiently advance the chemical conversion is reduced.

[0011] This diagram illustrates the liquid lead-acid batteries of the first and second embodiments, showing the battery case with the lid removed as viewed from above. This is a partial cross-sectional view of the liquid lead-acid batteries of the first and second embodiments, including the inter-cell connection portion, as viewed from the front (long side). This is a cross-sectional view showing a set of positive electrode plates, separators, and negative electrode plates constituting the laminate of the liquid lead-acid battery of the first embodiment. This is a front view of the laminate constituting the liquid lead-acid battery of the first embodiment, showing the arrangement of the grid-like portion of the positive electrode current collector plate and the grid-like portion of the negative electrode current collector plate within the laminate. This is a cross-sectional view showing a set of positive electrode plates, separators, and negative electrode plates constituting the laminate of the liquid lead-acid battery of the second embodiment. This is a front view of the laminate constituting the liquid lead-acid battery of the second embodiment, showing the arrangement of the grid-like portion of the positive electrode current collector plate and the grid-like portion of the negative electrode current collector plate within the laminate. This is a front view of the positive electrode current collector plate constituting the liquid lead-acid battery of the third embodiment. This is a cross-sectional view of the positive electrode plate constituting the liquid lead-acid battery of the third embodiment, where the positive electrode current collector plate corresponds to the cross-sectional view a-a in Figure 7. This figure illustrates the maximum circle when the square opening of the positive electrode current collector plate constituting the liquid lead-acid battery of the third embodiment is rectangular. This figure illustrates the range in which the radius A of the maximum circle and the thickness B of the layer made of the positive electrode mixture satisfy equation (1) for the positive electrode plate constituting the liquid lead-acid battery of the third embodiment. This figure illustrates the maximum circle when the square opening of the positive electrode current collector plate constituting the liquid lead-acid battery of the third embodiment is trapezoidal. This figure illustrates the maximum circle when the square opening of the positive electrode current collector plate constituting the liquid lead-acid battery of the third embodiment is trapezoidal.

[0012] The embodiments of the present invention will be described below, but the present invention is not limited to the embodiments shown below. In the embodiments shown below, technically preferred limitations are made for carrying out the present invention, but these limitations are not essential requirements of the present invention. In addition, although an electrolyte lead-acid battery is used as the lead-acid battery in the embodiments shown below, a valve-regulated lead-acid battery is also included in the lead-acid battery of the present invention.

[0013] <First Embodiment> [Overall Battery Configuration] The liquid lead-acid battery of the first embodiment has a monoblock type battery case 1 and six electrode plate groups 3 housed in each cell chamber 4, as shown in Figure 1. The battery case 1 is rectangular in shape and has a pair of first walls 11 formed on a pair of long sides of the rectangle that forms the bottom surface, and a pair of second walls 12 formed on a pair of short sides. The inside of the battery case 1 is divided into six cell chambers 4 by five partition walls 13 parallel to the second walls 12. Each of the six cell chambers 4 houses one electrode plate group 3 and is filled with electrolyte. The electrolyte is dilute sulfuric acid containing aluminum ions at a concentration of 0.02 mol / L or more and 0.2 mol / L or less. As shown in Figure 1, the arrangement direction of the cell chambers 4 is the X direction (long side of the battery case 1), and the direction perpendicular to this is the Y direction (short side of the battery case 1).

[0014] As shown in Figure 2, each electrode plate group 3 has a laminate 6. The laminate 6 is composed of a plurality of alternatingly arranged positive electrode plates 10 and negative electrode plates 20, and a separator 30 placed between the positive electrode plates 10 and the negative electrode plates 20. The number of negative electrode plates 20 constituting the laminate 6 is one more than the number of positive electrode plates 10. As shown in Figure 3, the positive electrode plate 10 is composed of a positive electrode current collector plate 101 and a positive electrode mixture (a mixture containing positive electrode active material) 102. The positive electrode current collector plate 101 has a rectangular grid-like portion 101a and an ear portion 101b protruding from one side of the rectangle forming the grid-like portion 101a.

[0015] The positive electrode mixture 102 is held in the grid-like portion 101a. The positive electrode mixture 102 is filled into the openings of the grid-like portion 101a and also exists in layers on both plate surfaces (both end faces in the thickness direction) of the grid-like portion 101a. The layered positive electrode mixture 102 is formed continuously with the unformed material filled into the openings of the grid-like portion 101a. In Figure 3, only the layered positive electrode mixture 102 is shown. In Figure 2, the grid-like portion 101a in which the positive electrode mixture 102 is held is indicated by reference numeral 111.

[0016] The lugs 101b of the positive electrode plate 10 are positioned offset to one side from the center in the width direction (the direction perpendicular to the plane of the paper in Figures 2 and 3) of the grid-like portion 101a. The negative electrode plate 20 is composed of a negative electrode current collector plate 201 and a negative electrode mixture (a mixture containing a negative electrode active material) 202. The negative electrode current collector plate 201 has a rectangular grid-like portion 201a, lugs 201b protruding from one side (upper frame bone) of the rectangle forming the grid-like portion 201a, and feet 201c protruding downward from the lower frame bone.

[0017] The negative electrode mixture 202 is held in the grid-like portion 201a. The negative electrode mixture 202 is filled into the openings of the grid-like portion 201a and also exists in layers on both plate surfaces (both end faces in the thickness direction) of the grid-like portion 201a. The layered negative electrode mixture 202 is formed continuously with the unformed material filled into the openings of the grid-like portion 201a. In Figure 3, only the layered negative electrode mixture 202 is shown. In Figure 2, the grid-like portion 201a in which the negative electrode mixture 202 is held is indicated by reference numeral 211. The tabs 201b of the negative electrode plate 20 are positioned offset from the center in the width direction of the grid-like portion (the direction perpendicular to the plane of the paper in Figures 2 and 3). The separator 30 is made of porous polyethylene, and as shown in Figure 3, the positive electrode plate 10 is housed in the bag-shaped separator 301.

[0018] As shown in Figures 1 and 2, each electrode plate group 3 further includes a positive electrode strap 71 and a negative electrode strap 72 connecting electrode plates of the same polarity, and in those housed in cells at both ends, a positive electrode intermediate pole 71a and a negative electrode intermediate pole 72a rising from the positive electrode strap 71 and the negative electrode strap 72, respectively. The positive electrode strap 71 and the negative electrode strap 72 connect the tabs 101b of the multiple positive electrode plates 10 and the tabs 201b of the negative electrode plates 20 that constitute the laminate 6 at different positions in the width direction of the positive electrode plates 10 and the negative electrode plates 20 (the direction that becomes the Y direction when housed in the cell chamber 4).

[0019] The electrode plate groups 3 housed in the cell chambers 4 located at both ends in the cell arrangement direction each have a positive terminal pole 8 and a negative terminal pole 9, which serve as external terminals. The positive terminal pole 8 and the negative terminal pole 9 are formed on the positive strap 71 and the negative strap 72 via small pieces 71b and 72b, respectively. Each electrode plate group 3 is housed in the cell chamber 4 with the stacking direction of the laminate 6 aligned with the X direction, and the plate surfaces of the positive electrode plate 10 and the negative electrode plate 20 aligned with the vertical direction of the cell chamber 4. The positive intermediate pole 71a and the negative intermediate pole 72a of adjacent cell chambers 4 are resistance welded, electrically connecting adjacent cells in series. Furthermore, the tops of all cell chambers 4 are sealed by fixing a lid (not shown) to the battery case 1. The positive terminal pole 8 and the negative terminal pole 9 penetrate the lid and are exposed to the outside.

[0020] [Regarding the positive and negative electrode plates] Further explanation of the positive and negative electrode plates follows. The positive electrode current collector plate 101, which constitutes the positive electrode plate 10, is a stamped product made from a rolled sheet of lead alloy. The thickness of the positive electrode current collector plate 101 is 0.8 mm or more and 1.2 mm or less. The grid-like portion 101a of the positive electrode current collector plate 101 is rectangular. The negative electrode current collector plate 201, which constitutes the negative electrode plate 20, is a cast product made of lead alloy. The grid-like portion 201a of the negative electrode current collector plate 201 is rectangular. The thickness of the positive electrode current collector plate 101 is smaller than the thickness of the negative electrode current collector plate 201. The ratio of the thickness of the positive electrode current collector plate 101 to the thickness of the negative electrode current collector plate 201 is, for example, 0.8 or more and less than 1.0.

[0021] As shown in Figure 4, when the positive electrode current collector plate 101 and the negative electrode current collector plate 201 are stacked on top of each other, the grid-like portion 101a of the positive electrode current collector plate 101 is located outside the outer periphery of the grid-like portion 201a of the negative electrode current collector plate 201. In other words, the apparent flat area of ​​the grid-like portion 101a of the positive electrode current collector plate 101 (the product of the dimension in the direction in which the tabs 101b of the grid-like portion 101a extend (height) and the dimension in the direction perpendicular thereto (width)) is larger than the apparent flat area of ​​the grid-like portion 201a of the negative electrode current collector plate 201 (the product of the dimension in the direction in which the tabs 201b of the grid-like portion 201a extend (height) and the dimension in the direction perpendicular thereto (width)). For the manufacturing method of the liquid lead-acid battery of the first embodiment, conventionally known methods can be employed. In conventionally known methods, an electrode plate group assembled using a positive electrode packing plate and a negative electrode packing plate is placed in an electrolytic cell, and electrolytic cell formation is performed to convert the unformed positive electrode mixture into a positive electrode mixture and the unformed negative electrode mixture into a negative electrode mixture, thereby converting the positive electrode packing plate and the negative electrode packing plate into a positive electrode plate and a negative electrode plate.

[0022] [Function and Effects] In the lead-acid battery of the first embodiment, the thickness of the positive electrode current collector plate is 0.8 mm or more and 1.2 mm or less, and less than or equal to the thickness of the negative electrode current collector plate, and the ratio of the thickness of the positive electrode current collector plate to the thickness of the negative electrode current collector plate is 0.8 or more and less than 1.0. First, because the thickness of the positive electrode current collector plate is less than or equal to the thickness of the negative electrode current collector plate, the difference in chemical conversion efficiency between the positive electrode plate and the negative electrode plate is reduced compared to the case where the thickness of the positive electrode current collector plate is greater than the thickness of the negative electrode current collector plate. Therefore, the amount of chemical conversion electricity required to sufficiently advance the chemical conversion can be reduced. In addition, because the ratio of the thickness of the positive electrode current collector plate to the thickness of the negative electrode current collector plate is 0.8 or more and less than 1.0, the chemical conversion efficiency of the positive electrode plate is further improved compared to the case where this ratio falls outside this range. Furthermore, because the thickness of the positive electrode current collector plate is 0.8 mm or more and 1.2 mm or less, the current collection efficiency of the positive electrode plate in the chemical conversion process is particularly high, and the chemical conversion efficiency of the positive electrode plate is particularly improved.

[0023] Furthermore, in the lead-acid battery of the first embodiment, dilute sulfuric acid containing aluminum ions at a concentration of 0.02 mol / L or more and 0.2 mol / L or less is used as the electrolyte. Compared to the case where dilute sulfuric acid not containing aluminum ions within the above concentration range is used, the crystals of lead sulfate in the electrode plates produced in the conversion process are made non-uniform, and the reaction from lead sulfate to lead oxide is promoted, thereby improving the conversion efficiency. In addition, in the lead-acid battery of the first embodiment, the number of negative electrode plates in the electrode plate group is one more than the number of positive electrode plates. Compared to the case where the number of both is the same, the number of surfaces of the positive electrode plate facing the negative electrode plate is increased, thereby improving the conversion efficiency of the positive electrode plate.

[0024] <Second Embodiment> The liquid lead-acid battery of the second embodiment is the same as the liquid lead-acid battery of the first embodiment, except for the following points. As shown in Figure 5, unlike the first embodiment, the negative electrode plate 20 does not have feet 201c. The negative electrode current collector plate 201 that constitutes the negative electrode plate 20 is a stamped product made from a rolled sheet of lead alloy. Also, the grid-like portion 201a of the negative electrode current collector plate 201 is rectangular. As shown in Figure 6, when the positive electrode current collector plate 101 and the negative electrode current collector plate 201 are stacked on top of each other, the grid-like portion 201a of the negative electrode current collector plate 201 is located outside the outer periphery of the grid-like portion 101a of the positive electrode current collector plate 101. In other words, the apparent flat area of ​​the grid-like portion 101a of the positive electrode current collector plate 101 is smaller than the apparent flat area of ​​the grid-like portion 201a of the negative electrode current collector plate 201.

[0025] [Function and Effects] In the lead-acid battery of the second embodiment, the assumed flat area of ​​the grid-like portion of the negative electrode current collector plate is larger than the assumed flat area of ​​the grid-like portion of the positive electrode current collector plate. Compared to the case where the assumed flat areas of both are the same size, the number of surfaces of the positive electrode plate facing the negative electrode plate increases, thereby improving the chemical conversion efficiency of the positive electrode plate.

[0026] <Third Embodiment> The liquid lead-acid battery of the third embodiment is the same as the liquid lead-acid battery of the first embodiment, except for the following points. [Regarding the positive electrode plate and negative electrode plate] The positive electrode current collector plate 101 constituting the positive electrode plate 10 is a punched product made from a rolled sheet of lead alloy. The thickness of the positive electrode current collector plate 101 is 0.8 mm or more and 1.2 mm or less. Also, as shown in Figure 7, the grid-like portion 101a of the positive electrode current collector plate 101 is rectangular. The grid-like portion 101a of the positive electrode current collector plate 101 is formed by an outer frame 151 and a plurality of parallel horizontal bones 152 and a plurality of vertical bones 153 that intersect with the horizontal bones 152, and has a rectangular opening 155 formed by two adjacent horizontal bones 152 and two adjacent vertical bones 153.

[0027] As shown in Figure 8, in the positive electrode packing plate 105, which is formed into a positive electrode plate by chemical conversion, the opening 155 is filled with unconverted positive electrode mixture material 115, and a layer (hereinafter referred to as the "unconverted material layer") 116 made of unconverted positive electrode mixture material is formed on both plate surfaces (both end faces in the thickness direction) 156, 157 of the lattice-shaped portion 101a. The unconverted material layer 116 is formed continuously with the unconverted material filled in the opening 155 of the lattice-shaped portion 101a. Furthermore, the dimension A (mm) of the rectangular opening 155 and the thickness B (mm) of the unconverted material layer 116 of the positive electrode packing plate are given by √(A 2 +B ２ ) ≤ 5.1 (mm) ... (1) is satisfied. Here, in this embodiment, since the unformed material layer 116 is formed on both plate surfaces (both end faces in the thickness direction) 156, 157 of the lattice-shaped portion 101a, the larger of the unformed material layer 116 formed on end face 156 and the unformed material layer 116 formed on end face 157 is defined as "B". As will be explained below, A is the radius of the largest circle that is located inside the rectangle (quadrilateral) forming the opening 155 in a plan view and is tangent to two or more of the four sides constituting the rectangle.

[0028] As shown in Figure 9, in this example, there are two circles that are tangent to three sides, defined as "circles that exist inside the rectangle forming the opening 155 in plan view and are tangent to two or more of the four sides constituting the rectangle." These are the first circles 161, which are tangent to the two horizontal bars 152 that are the longer sides and the one vertical bar 153 that is the shorter side. In addition, there are infinitely many second circles 162 that are tangent to two sides, such as the two horizontal bars 152. Since all these circles are the same size, all of them are the largest circles, and their radius is defined as dimension A. In Figures 9(a) and 9(b), the centers of the two first circles 161 are P1 and P2, respectively. In Figure 9(a), the second circle 162 is also shown, and its center is P3.

[0029] Furthermore, the point on the straight line L connecting the centers P1 and P2 of the two first circles 161 is the point in the quadrilateral forming the opening where the distance to the nearest lattice bone (vertical or horizontal bone; in this figure, horizontal bone 152) is maximized (in this figure, the perpendicular to the horizontal bone 152), and this distance corresponds to A. Since the chemical conversion efficiency deteriorates as the distance from the lattice bone in the opening increases, good chemical conversion efficiency can be obtained by setting A to a value below a certain value, using it as one of the parameters. Here, equation (1) is adopted, in which the thickness B of the positive electrode mixture layer on the positive electrode packing plate is also a parameter.

[0030] Figure 10 is a diagram corresponding to the b-b cross-section of Figure 9(a), and only the upper side of the unformed material layer 116 of the positive electrode packing plate is shown. And √(A 2 +B ２ The dimensions A (mm) and the thickness B (mm) of the unformed material layer 116 on the upper side of the positive electrode packing plate are set so as to satisfy ) ≤ 5.1 (mm) ... (1). Circle C is centered on point O at the inner corner of the cross section of the horizontal bone 152 and has a radius of √(A 2 +B ２ ) is a circle. Point P is a point on the line L in Figure 9(a), and is the point on the plate surface of the lattice part that is furthest from the two horizontal bones 152. Point Q is the point where the circles C of the two horizontal bones 152 that constitute the opening 155 intersect. The positive electrode mixture at point Q is located at the position furthest in three dimensions from the four lattice bones (two horizontal bones 152 and two vertical bones 153) that constitute the opening 155.

[0031] The example shown in FIG. 11 is an example in which the quadrilateral forming the opening 155 is a trapezoid. The opening 155 is constituted by four sides: a first transverse rib 152a and a second transverse rib 152b that are parallel to each other, and a first vertical rib 153a and a second vertical rib 153b that are not parallel to each other. In the example of FIG. 11, among the circles that exist inside the trapezoid forming the opening 155 in plan view and are in contact with two or more sides of the trapezoid, the circles in contact with three sides include a circle 171 shown in FIG. 11(a) and a circle 172 shown in FIG. 11(b). The center of each circle is point P. As shown in FIG. 11(a), the circle 171 is in contact with the longer transverse rib 152b, the first vertical rib 153a, and the second vertical rib 153b. As shown in FIG. 11(b), the circle 172 is in contact with the shorter transverse rib 152a, the first vertical rib 153a, and the second vertical rib 153b.

[0032] As circles in contact with two sides of the trapezoid, a circle 173 and a circle 174 which are part of them are shown in FIG. 11(b). Among these circles, the circle 171 shown in FIG. 11(a) is the largest circle (maximum circle) among the circles in contact with two or more sides of the trapezoid. The radius of this circle 171 is dimension A. Note that, as shown in FIG. 11, the dimension A is also the radius of the smallest circle among the circles inscribed in three sides in plan view in a plurality of configurations selected such that the total value of the angles formed by each two of the three sides constituting the quadrilateral that is the opening 155 in plan view is 180° or less. The sum of the formed angles for the circle 171 is 180° or less, and the sum of the formed angles for the circle 172 exceeds 180°.

[0033] Further, a circle 181 in FIG. 12 has the sum of the formed angles of 180° or less, and is a circle larger than the circle 171 shown in FIG. 11(a). Therefore, the circle 171 shown in FIG. 11(a) corresponds to "the smallest circle among the circles inscribed in three sides in plan view in a plurality of configurations selected such that the total value of the angles formed by each two of the three sides constituting the quadrilateral that is the opening 155 in plan view is 180° or less", and the radius of the circle 171 is A. Note that the circle 181 does not correspond to a circle existing inside the quadrilateral forming the opening 155 in plan view.

[0034] The point P, which is the center of the circle 171 shown in FIG. 11(a), is the point farthest from the four grid bones (the first transverse bone 152a, the second transverse bone 152b, the first longitudinal bone 153a, and the second longitudinal bone 153b) constituting the opening 155 on the plate surface of the grid portion. Also for the liquid lead-acid battery of the third embodiment, an electrode plate group assembled using the positive electrode filling plate 105 and the negative electrode filling plate is placed in a battery case, and container formation is performed, whereby the unformed material of the positive electrode mixture becomes part of the positive electrode mixture, and the unformed material of the negative electrode mixture becomes part of the negative electrode mixture.

[0035] [Operation and Effects] In the liquid lead-acid battery of the third embodiment, in addition to the operations and effects obtained by the liquid lead-acid battery of the first embodiment, the following operations and effects can be obtained. The dimension A (mm) related to the quadrangular opening 155 of the grid portion 101a and the thickness B (mm) of the unformed material layer 116 of the positive electrode filling plate 105 satisfy Formula (1), so that the unformed material of the positive electrode mixture is present within the opening and within a range of 5.1 mm from the surface corner (point C) of the grid portion, and is not present at positions more than 5.1 mm away. By achieving this state, electrical conductivity during formation is improved, formation efficiency is enhanced, and predetermined criteria can be satisfied.

[0036] If the dimension A is too small, the opening of the grid portion becomes too narrow, and when filling the opening with the unformed material of the positive electrode mixture, a required amount of the unformed material may not be filled. To prevent this, the dimension A is preferably 2.0 mm or more. In addition, the preferable upper limit of the dimension A is 5.0 mm for the reason that the unformed material easily falls off from the plate surface of the grid portion. The preferable range of the thickness B is 0.2 mm or more and 1.0 mm or less. When the thickness B is less than 0.2 mm, the amount of the unformed material on the plate surface of the grid portion is insufficient, and when the thickness B exceeds 1.0 mm, the unformed material easily falls off from the plate surface of the grid portion.

[0037] [Preparation of Test Batteries] Samples No. 1 to No. 30 were prepared as liquid lead-acid batteries with the same structure as the liquid lead-acid batteries of the first to third embodiments, with the configurations shown below. Samples No. 1 to No. 23 are B24 size liquid lead-acid batteries with a nominal voltage of 12V, and all configurations are the same except for changes in the thickness of the positive electrode current collector plate, the thickness of the negative electrode current collector plate, the aluminum ion content of the electrolyte, and the ratio of the total compound charge to the theoretical capacity of the positive electrode. In liquid lead-acid batteries No. 1 to No. 23, the relationship between the arrangement of the grid portion 101a of the positive electrode current collector plate 101 and the grid portion 201a of the negative electrode current collector plate 201 within the laminate is as shown in Figure 4.

[0038] Samples No. 24 and No. 25 are liquid lead-acid batteries of size B24 with a nominal voltage of 12V. They all have the same configuration except for variations in the number of negative electrodes and the assumed flat area of ​​the grid-like portion of the negative electrode. The relationship between the arrangement of the grid-like portion 101a of the positive electrode current collector plate 101 and the grid-like portion 201a of the negative electrode current collector plate 201 within the laminate in liquid lead-acid batteries No. 24 and No. 25 is as shown in Figure 6.

[0039] Samples No. 26 to No. 30 are liquid lead-acid batteries of size B24, with a nominal voltage of 12V. The thickness of the positive electrode current collector plate is 0.8 mm, the thickness of the negative electrode current collector plate is 1.0 mm, the aluminum ion content of the electrolyte is 0.1 mol / L, and the total chemical charge is 170%. The dimensions of the rectangles forming the openings of the grid-like portion, dimension A, and the thickness B of the un-chemical layer 116 were changed. In liquid lead-acid batteries No. 26 to No. 30, the relationship between the arrangement of the grid-like portion 101a of the positive electrode current collector plate 101 and the grid-like portion 201a of the negative electrode current collector plate 201 within the laminate is as shown in Figure 4.

[0040] 〔No.1〕 <Production of Positive Electrode Plate Prior to Formation> A positive electrode current collector plate was produced by sequentially performing a slab casting step, a rolling step, and a punching step. First, the slab casting step was performed by the following method. A lead alloy block consisting of 0.06 mass% Ca, 1.6 mass% Sn, 0.02 mass% Al, and the balance being lead and unavoidable impurities was prepared and melted by heating to obtain a molten metal. This molten metal was poured between two opposing metal rolls, and the molten metal was cooled by the metal rolls to obtain a lead alloy slab.

[0041] Next, the obtained lead alloy slab was passed between a pair of upper and lower rolling rolls to perform a rolling step at a reduction ratio of 90%, thereby obtaining a rolled sheet with a width of 320 mm and a thickness of 1.2 mm. Next, the obtained rolled sheet was subjected to a press molding machine and punched in the thickness direction to obtain a positive electrode current collector plate 101 having a shape in which an ear portion 101b extends upward from the upper frame bone of a grid portion 101a.

[0042] Regarding the dimensions of the grid portion 101a, the dimension (height) in the direction in which the ear portion 101b extends is 113.0 mm, the dimension (width) in the direction perpendicular thereto is 105.0 mm, and the thickness is 1.2 mm. The apparent planar area of the grid portion 101a is 113.0 × 105.0 = 11865 mm 2 . Regarding the dimensions of the ear portion 101b, the width is 10 mm and the height is 15 mm. The ear portion 101b extends from between the center in the width direction of the grid portion 101a and one end portion (the right end portion in Fig. 4). After the grid portion 101a of the obtained positive electrode current collector plate was filled with a positive electrode paste produced by a conventional method, aging and drying were performed by a conventional method to obtain a positive electrode plate (positive electrode filled plate) 10 prior to formation.

[0043] <Manufacturing of the negative electrode plate before chemical conversion> Using a lead alloy consisting of 0.09 mass% Ca, 0.4 mass% Sn, 0.02 mass% Al, and the remainder being lead and unavoidable impurities, a negative electrode current collector plate 201 was obtained by continuous casting, as shown in Figure 4, with ear portions 201b extending upward from the upper frame bone of the lattice portion 201a and foot portions 201c extending downward from the lower frame bone. The dimensions of the lattice portion 201a are 108.5 mm in the direction in which the ear portions 201b extend (height), 102.0 mm in the direction perpendicular to this (width), and 1.0 mm in thickness. The estimated flat area of ​​the lattice portion 201a is 108.5 × 102.0 = 11067 mm² 2 That is the case.

[0044] The dimensions of the ear portion 201b are 10 mm in width and 15 mm in height. The ear portion 201b extends from between the widthwise center and the other end (left end in Figure 4) of the grid-like portion 201a. After filling the grid-like portion 201a of the obtained negative electrode current collector plate with negative electrode paste prepared by the following method, the plate was matured and dried using a normal method to obtain a negative electrode plate (negative electrode filled plate) 20 before chemical formation. The negative electrode paste was prepared by adding necessary additives such as conductive carbon to lead powder, mixing them by dry mixing, then adding water and kneading, and finally adding dilute sulfuric acid to the resulting water mixture and kneading.

[0045] <Preparation of electrode plate groups before chemical formation> As separator 30, a porous polyethylene separator with vertical ribs was used, and a bag-shaped separator 301 was obtained by making it into a bag shape with the vertical rib side facing inward. Specifically, separator 30 with a total thickness of 0.7 mm was prepared. One positive electrode packed plate for each sample was placed in each of these bag-shaped separators. Six laminates were prepared by alternately stacking six bag-shaped separators containing positive electrode packed plates and seven negative electrode packed plates. Next, using a COS (cast-on-strap) casting apparatus, straps and intermediate electrode pillars (straps and terminal electrode pillars in cells located at both ends) were formed on the positive electrode packed plates and negative electrode packed plates of the six obtained laminates, respectively, to obtain six electrode plate groups.

[0046] <Battery Assembly> Next, the six electrode plates obtained were placed in the six cell chambers of a polypropylene monoblock type battery case. Then, resistance welding of the intermediate electrode poles between adjacent cell chambers and heat welding of the battery case and lid were performed using the usual method. Next, dilute sulfuric acid with a specific gravity of 1.240 (at 20°C) was injected into each cell chamber through the respective filling ports on the lid as the electrolyte. Finally, the filling ports were sealed with vent plugs to assemble the unformed liquid lead-acid battery.

[0047] <Formation Process> Subsequently, the battery case was reformed using a standard method until the total charge (Ah) reached 200% of the theoretical capacity of the positive electrode. This transformed the positive electrode and negative electrode filler plates into positive and negative electrode plates, completing the No. 1 liquid lead-acid battery. The amount of electricity required for this battery case reformation, i.e., the amount of electricity used for reformation (Ah), was recorded.

[0048] [No.2] Dilute sulfuric acid with an aluminum ion concentration of 0.1 mol / L and a specific gravity of 1.240 (at 20°C) was obtained by adding aluminum sulfate to dilute sulfuric acid, and this was used as the electrolyte. Except for this, liquid lead-acid battery No.2 was completed in the same manner as No.1. [No.3] Liquid lead-acid battery No.3 was completed in the same manner as No.2, except that the battery case was reformed until the total charge capacity (Ah) reached 170% of the theoretical capacity of the positive electrode.

[0049] [No. 4 to No. 7] Except for using negative electrode current collectors with thicknesses of 1.2 mm, 1.3 mm, 1.5 mm, and 1.7 mm, while keeping the amount of negative electrode mixture per negative electrode plate unchanged, liquid lead-acid batteries No. 4 to No. 7 were completed in the same manner as No. 3. [No. 8 to No. 12] Except for using positive electrode current collectors with a thickness of 1.0 mm and negative electrode current collectors with thicknesses of 0.8 mm, 1.0 mm, 1.1 mm, 1.3 mm, and 1.4 mm, liquid lead-acid batteries No. 8 to No. 12 were completed in the same manner as No. 3, while keeping the amount of positive electrode mixture per positive electrode plate and the amount of negative electrode mixture per negative electrode plate unchanged, positive electrode current collectors with a thickness of 1.0 mm and negative electrode current collectors with thicknesses of 0.8 mm, 1.0 mm, 1.1 mm, 1.3 mm, and 1.4 mm. [No. 13 to No. 17] Except for keeping the amount of positive electrode compound per positive electrode plate and the amount of negative electrode compound per negative electrode plate unchanged, and using a positive electrode current collector plate with a thickness of 0.8 mm and negative electrode current collector plates with thicknesses of 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, and 1.1 mm, liquid lead-acid batteries No. 13 to No. 17 were completed in the same manner as No. 3.

[0050] [No. 18-19] Except for keeping the amount of positive electrode mixture per positive electrode plate and the amount of negative electrode mixture per negative electrode plate unchanged, and using positive electrode current collector plates with thicknesses of 0.7 mm and 1.3 mm, and negative electrode current collector plates with thicknesses of 0.8 mm and 1.6 mm, liquid lead-acid batteries No. 18-19 were completed in the same manner as No. 3. [No. 20-23] Except for keeping the amount of positive electrode mixture per positive electrode plate and the amount of negative electrode mixture per negative electrode plate unchanged, and using positive electrode current collector plates with a thickness of 0.8 mm and negative electrode current collector plates with a thickness of 1.0 mm, the concentration of aluminum ions contained in the electrolyte was changed, and liquid lead-acid batteries No. 20-23 were completed in the same manner as No. 3.

[0051] [No. 24] The negative electrode current collector plate was manufactured using the same method as the positive electrode current collector plate, rather than by casting. That is, the negative electrode current collector plate 201 has the shape shown in Figure 6, and the dimensions of the grid-like portion 201a are 113.5 mm in the direction in which the tabs 201b extend (height), 105.5 mm in the direction perpendicular to this (width), and 1.0 mm in thickness. The dimensions of the tabs 201b are 10 mm in width and 15 mm in height. The estimated flat area of ​​the grid-like portion 201a is 113.5 × 105.5 = 11974 mm²2 The ear portion 201b extends from between the widthwise center of the grid portion 201a and the other end (the left end in Figure 6). The grid portion 101a of the positive electrode current collector plate 101 and the grid portion 201a of the negative electrode current collector plate 201 are arranged in the relationship shown in Figure 6. That is, the apparent flat area of ​​the grid portion is larger at the negative electrode than at the positive electrode. Except for this, the liquid lead-acid battery No. 24 was completed using the same method as No. 16. The amount of negative electrode mixture per negative electrode plate was also the same as in No. 16. [No. 25] The liquid lead-acid battery No. 25 was completed using the same method as No. 24, except that the total amount of negative electrode mixture per laminate was not changed and the number of negative electrode plates constituting the laminate was the same as the positive electrode plates, six.

[0052] [No. 26] Except for the following points, the liquid lead-acid battery of No. 26 was completed in the same way as No. 3. As the positive electrode current collector plate, a rectangular piece with dimensions of 11 mm x 11 mm forming the openings of the grid-like section was used, making dimension A 5.5 mm, and the thickness B of the unformed material layer 116 1.0 mm. √(A 2 +B ２ The value of ) is 5.6 mm. [No. 27] Except for the following points, the liquid lead-acid battery of No. 27 was completed in the same way as No. 3. As the positive electrode current collector plate, a square with dimensions of 10 mm x 10 mm for the rectangular openings in the grid-like section was used, so that dimension A was 5.0 mm and the thickness B of the unformed material layer 116 was 1.0 mm. √(A 2 +B ２ The value of ) is 5.1 mm. [No. 28] Except for the following points, the liquid lead-acid battery of No. 28 was completed in the same way as No. 3. As the positive electrode current collector plate, a rectangular piece with dimensions of 10 mm x 10 mm for the openings in the grid-like section was used, so that dimension A was 5.0 mm and the thickness B of the unformed material layer 116 was 1.4 mm. √(A 2 +B ２ The value of ) is 5.2 mm.

[0053] [No. 29] Except for the following points, the liquid lead-acid battery of No. 29 was completed in the same way as No. 3. By using a rectangular plate with dimensions of 10 mm x 9 mm for the openings in the grid-like section as the positive electrode current collector plate, dimension A was set to 4.5 mm, and the thickness B of the unformed material layer 116 was set to 1.0 mm. √(A 2 +B ２ The value of ) is 4.6 mm. [No. 30] Except for the following points, the liquid lead-acid battery of No. 30 was completed in the same way as No. 3. As the positive electrode current collector plate, a square with dimensions of 7 mm x 7 mm for the rectangular openings in the grid-like section was used, making dimension A 3.5 mm and the thickness B of the unformed material layer 116 1.0 mm. √(A 2 +B ２ The value of ) is 3.6 mm.

[0054] [Evaluation Test] [No. 1 to No. 23] For liquid lead-acid batteries No. 1 to No. 23, the amount of lead sulfate contained in the positive electrode plate was measured. In addition, the rated cold cranking current (CCA) and 20-hour rate capacity were measured, and the average value of both was calculated as the discharge performance value. Then, relative values ​​[%] were calculated for the recorded amount of chemical charge, the value obtained by dividing the measured amount of lead sulfate in the positive electrode plate by the amount of positive electrode mixture (lead sulfate content of the positive electrode plate), and the calculated discharge performance value, with the value of liquid lead-acid battery No. 1 set to 100%.

[0055] Furthermore, the relative values ​​of the amount of generated electricity, the lead sulfate content of the positive electrode plate, and the discharge performance value were judged as follows. Since a higher value of the amount of generated electricity increases manufacturing costs, a lower value of the amount of generated electricity is preferable. Specifically, if the relative value of the amount of generated electricity to No. 1 is more than 100%, it is judged as "×" because manufacturing costs will increase; if it is between 95% and 100%, it is judged as "△" because manufacturing costs will be the same or slightly reduced; if it is between 90% and less than 95%, it is judged as "〇" because manufacturing costs will be reduced; and if it is less than 90%, it is judged as "◎" because manufacturing costs will be significantly reduced.

[0056] A lower lead sulfate content in the positive electrode plate indicates less residual un-chemical material and that the positive electrode plate is sufficiently chemically processed. In other words, a lower lead sulfate content in the positive electrode plate is preferable because it indicates that there is room to further reduce the amount of chemically generated electricity. Specifically, if the relative value of the lead sulfate content of the positive electrode plate to No. 1 is more than 100%, the amount of chemically generated electricity cannot be reduced, so it is judged as "×"; if it is between 80% and 100%, the amount of chemically generated electricity can be reduced slightly, so it is judged as "△"; if it is between 60% and less than 80%, the amount of chemically generated electricity can be reduced to some extent, so it is judged as "〇"; and if it is less than 60%, the amount of chemically generated electricity can be reduced significantly, so it is judged as "◎".

[0057] A higher discharge performance value indicates better battery performance and that the positive electrode is sufficiently charged. In other words, a higher discharge performance value is preferable because it indicates that there is room to further reduce the amount of generated electricity. Specifically, if the relative value of the discharge performance value to No. 1 is less than 100%, it is judged as "×", if it is between 100% and 105%, it is judged as "△", if it is between 105% and 110%, it is judged as "〇", and if it is above 110%, it is judged as "◎".

[0058] Furthermore, the overall evaluation was performed as follows: In the "determination of chemical charge," "determination of lead sulfate content of the positive electrode plate," and "determination of discharge performance value," "◎" was assigned 3 points, "○" 2 points, "△" 1 point, and "×" 0 points. A total score was calculated, and if the value was 9 or higher, it was judged as "◎," if it was 7 or 8, it was judged as "○," if it was between 2 and 6, it was judged as "△," and if it was 1 or lower, it was judged as "×." The composition of each sample, the test results and their judgments, and the overall evaluation are summarized in Table 1.

[0059]

[0060] The results in Table 1 show the following: In the comparison between No. 1 and No. 2, although the positive electrode current collector is thicker than the negative electrode current collector, the inclusion of aluminum ions in the electrolyte improves the lead sulfate content and discharge performance of the positive electrode. In the comparison between No. 2 and No. 3, when the positive electrode current collector is thicker than the negative electrode current collector, reducing the total charge amount during battery cell formation from 200% to 170% of the theoretical capacity ratio of the positive electrode worsens the lead sulfate content and discharge performance of the positive electrode. In the comparison between No. 3 to No. 7, when the positive electrode current collector is 1.2 mm thick, the overall evaluation changes depending on the thickness of the negative electrode current collector, and the overall evaluation is particularly high when the ratio of the thickness of the positive electrode current collector to the thickness of the negative electrode current collector is 0.8 or 0.9. In the comparison of No. 8 to No. 12, when the positive electrode current collector plate is 1.0 mm thick, the overall rating changes depending on the thickness of the negative electrode current collector plate, and the overall rating is particularly high when the ratio of the thickness of the positive electrode current collector plate to the thickness of the negative electrode current collector plate is 0.8 or 0.9.

[0061] In the comparison of No. 13 to No. 17, when the positive electrode current collector plate is 0.8 mm thick, the overall rating changes depending on the thickness of the negative electrode current collector plate, and the overall rating is particularly high when the ratio of the thickness of the positive electrode current collector plate to the thickness of the negative electrode current collector plate is 0.8 or 0.9. In the comparison of No. 6, No. 11, No. 16, No. 18, and No. 19, when the ratio of the thickness of the positive electrode current collector plate to the thickness of the negative electrode current collector plate is 0.8 or 0.9, and the thickness of the positive electrode current collector plate is 0.8 mm, 1.0 mm, or 1.2 mm, the overall rating is higher than when the thickness of the positive electrode current collector plate is 0.7 mm or 1.3 mm. In a comparison of No. 16 and No. 20-23, when the thickness of the positive electrode current collector plate is 0.8 mm and the thickness of the negative electrode current collector plate is 1.0 mm, using dilute sulfuric acid containing aluminum ions at a concentration of 0.02 mol / L to 0.2 mol / L as the electrolyte results in a particularly high overall rating.

[0062] [No. 24-25] For liquid lead-acid batteries No. 24 and No. 25, the amount of lead sulfate contained in the positive electrode plate was measured. Then, the relative value [%] of the recorded amount of chemically generated electricity and the value obtained by dividing the measured amount of lead sulfate in the positive electrode plate by the amount of positive electrode mixture (lead sulfate content of the positive electrode plate) was calculated, with the value of liquid lead-acid battery No. 1 set to 100%. Furthermore, the relative value of the chemically generated electricity was judged in the same way as for No. 1-23, and for the relative value of the lead sulfate content of the positive electrode plate, it was judged as "×" if it was more than 100%, "△" if it was between 80% and 100%, "〇" if it was between 55% and less than 80%, and "◎" if it was less than 55%.

[0063] Furthermore, the overall evaluation was performed as follows: For "Determination of the amount of chemically generated electricity" and "Determination of the lead sulfate content of the positive electrode plate," "◎" was assigned 3 points, "○" 2 points, "△" 1 point, and "×" 0 points. The total score was calculated, and if the value was 6 or higher, it was marked "◎," if it was 4 or 5, it was marked "○," if it was 2 or 3, it was marked "△," and if it was 1 or lower, it was marked "×." The composition of each sample, the test results and their evaluations, and the overall evaluation are summarized in Table 2. Note that battery No. 16 has the same composition as battery No. 24 except that it does not satisfy the condition "the assumed flat area of ​​the grid-like part of the positive electrode current collector plate is smaller than the assumed flat area of ​​the grid-like part of the negative electrode current collector plate," so it was included in Table 2 for comparison.

[0064]

[0065] The results in Table 2 show the following: In liquid lead-acid batteries No. 16, No. 24, and No. 25, which have a positive electrode current collector thickness of 0.8 mm and a negative electrode current collector thickness of 1.0 mm, and are laminated with six positive electrode plates, the liquid lead-acid battery No. 24, which satisfies both conditions of "having one more negative electrode plate than positive electrode plates" and "the assumed flat area of ​​the grid-like portion of the positive electrode current collector plate being smaller than the assumed flat area of ​​the grid-like portion of the negative electrode current collector plate", received a higher overall rating than the liquid lead-acid batteries No. 16 and No. 25, which did not satisfy either of these conditions.

[0066] [No. 26 to No. 30] For liquid lead-acid batteries No. 26 to No. 30, the lead sulfate content of the positive electrode plate was measured using the same method as above. The value obtained by dividing the amount of lead sulfate contained in the measured positive electrode plate by the amount of positive electrode mixture (lead sulfate content of the positive electrode plate) was then calculated as a relative value [%] with the value of liquid lead-acid battery No. 1 set to 100%, and this relative value was judged as follows: A lower lead sulfate content in the positive electrode plate indicates that there is less residual unprocessed material and that the positive electrode plate is sufficiently processed. In other words, a lower lead sulfate content in the positive electrode plate is preferable because it indicates that there is room to further reduce the amount of generated electricity.

[0067] Specifically, if the relative value of the lead sulfate content of the positive electrode plate to No. 1 was more than 100%, the amount of chemical electricity could not be reduced, so it was judged as "Poor: ×"; if it was between 80% and 100%, the amount of chemical electricity could be reduced somewhat, so it was judged as "Not bad, but insufficient: △"; if it was between 60% and less than 80%, the amount of chemical electricity could be reduced to some extent, so it was judged as "Good: ○"; if it was between 40% and less than 60%, the amount of chemical electricity could be reduced significantly, so it was judged as "Especially good: ◎"; and if it was less than 40%, the amount of chemical electricity could be reduced remarkably, so it was judged as "Outstandingly good: ☆". The composition of each sample, the test results, and their judgments are summarized in Table 3.

[0068]

[0069] The results in Table 3 show the following: In liquid lead-acid batteries No. 26 to No. 30, where the positive electrode current collector plate is 0.8 mm thick, the negative electrode current collector plate is 1.0 mm thick, contains 0.1 mol / L of aluminum ions, and the total chemical charge is 170% of the theoretical capacity of the positive electrode, liquid lead-acid batteries No. 27, No. 29, and No. 30, whose positive electrode filling plates satisfy equation (1), have a lower lead sulfate content in the positive electrode plate, better electrical conductivity during chemical conversion of the positive electrode plate, higher chemical conversion efficiency, and a significant reduction in the amount of chemically converted electricity compared to liquid lead-acid batteries No. 26 and No. 28, which do not satisfy equation (1). In particular, √(A 2 +B ２ In the No. 30 liquid lead-acid battery, where the diameter is 3.6 mm (4.0 mm or less), the chemical conversion efficiency of the positive electrode plate is significantly increased, and the amount of electricity converted can be significantly reduced.

[0070] 1. Battery case 4. Cell chamber 3. Electrode plate group 6. Laminate 71. Positive electrode strap 8. Positive electrode terminal pole 72. Negative electrode strap 9. Negative electrode terminal pole 10. Positive electrode plate (positive electrode filling plate) 101. Positive electrode current collector plate 101a. Grid-like portion of positive electrode current collector plate 101b. Ear portion of positive electrode current collector plate 102. Positive electrode mixture 105. Positive electrode filling plate 111. Grid-like portion holding the positive electrode mixture 115. Unformed material of positive electrode mixture 116. Unformed material layer (layer consisting of unformed material of positive electrode mixture) 151. Outer frame 152. Horizontal ribs 153. Vertical ribs 155. Opening 156. Plate surface of grid-like portion (end face in the thickness direction) 157. Plate surface of grid-like portion (end face in the thickness direction) 20. Negative electrode plate (negative electrode filling plate) 211 Grid-like portion holding the negative electrode mixture 201 Negative electrode current collector plate 201a Grid-like portion of the negative electrode current collector plate 201b Ear portion of the negative electrode current collector plate 201c Foot portion of the negative electrode current collector plate 202 Negative electrode mixture 30 Separator 301 Bag-shaped separator

Claims

1. A lead-acid battery comprising an electrode plate group and an electrolyte, wherein the electrode plate group has a laminate consisting of alternately arranged negative electrode plates and positive electrode plates, and a separator disposed between the negative electrode plate and the positive electrode plate, the positive electrode plate having a positive electrode current collector plate and a positive electrode mixture held in a grid-like portion of the positive electrode current collector plate, the negative electrode plate having a negative electrode current collector plate and a negative electrode mixture held in a grid-like portion of the negative electrode current collector plate, and the thickness of the positive electrode current collector plate being smaller than the thickness of the negative electrode current collector plate.

2. The lead-acid battery according to claim 1, wherein the electrolyte is dilute sulfuric acid containing aluminum ions at a concentration of 0.02 mol / L or more and 0.2 mol / L or less.

3. The lead-acid battery according to claim 1, wherein the thickness of the positive electrode current collector plate is 0.8 mm or more and 1.2 mm or less.

4. The lead-acid battery according to claim 1, wherein the ratio of the thickness of the positive electrode current collector plate to the thickness of the negative electrode current collector plate is 0.8 or more and less than 1.

0.

5. The lead-acid battery according to claim 1, wherein the assumed flat area of ​​the grid-like portion of the positive electrode current collector plate is smaller than the assumed flat area of ​​the grid-like portion of the negative electrode current collector plate, and the laminate has one more negative electrode plate than positive electrode plates.

6. The lead-acid battery according to claim 1, wherein the grid-like portion of the positive electrode current collector plate is formed by an outer frame, a plurality of parallel horizontal ribs and a plurality of vertical ribs intersecting the horizontal ribs arranged within the outer frame, and has a rectangular opening formed by two adjacent horizontal ribs and two adjacent vertical ribs, the positive electrode packing plate which is the positive electrode plate before chemical formation, has the unformed positive electrode mixture material filled in the opening, and a layer made of the unformed positive electrode mixture material is formed on at least one end face in the thickness direction of the grid-like portion, continuously with the filled unformed material, and the radius A (mm) of the largest circle that is located inside the rectangle in a plan view and touches two or more of the four sides constituting the rectangle, and the thickness B (mm) of the layer of the positive electrode packing plate satisfy the following equation (1). 2 +B ２ )≦5.1(mm)…(1) 7. The electrode plate group comprises an electrode plate group and an electrolyte, the electrode plate group having a laminate consisting of alternatingly arranged negative electrode plates and positive electrode plates, and a separator disposed between the negative electrode plate and the positive electrode plate, the positive electrode plate having a positive electrode current collector plate and a positive electrode mixture held in a grid-like portion of the positive electrode current collector plate, the negative electrode plate having a negative electrode current collector plate and a negative electrode mixture held in a grid-like portion of the negative electrode current collector plate, the grid-like portion of the positive electrode current collector plate being formed by an outer frame, a plurality of parallel horizontal ribs and a plurality of vertical ribs intersecting the horizontal ribs arranged within the outer frame, and having a rectangular opening formed by two adjacent horizontal ribs and two adjacent vertical ribs, the positive electrode packing plate, which is the positive electrode plate before chemical formation, has the unformed positive electrode mixture filled in the opening, A lead-acid battery wherein a layer made of the unformed positive electrode mixture is formed on at least one end face in the thickness direction of the grid-like portion, continuously with the filled unformed material, and the radius A (mm) of the largest circle that is located inside the rectangle in a plan view and touches two or more of the four sides constituting the rectangle, and the thickness B (mm) of the layer of the positive electrode filling plate satisfy the following equation (1): √(A 2 +B ２ )≦5.1(mm)…(1)

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