Liquid lead-acid battery

Abstract

The present application provides a new liquid lead storage battery with good potential distribution of positive grid body and stable performance in high current extraction applications. The grid-shaped substrate (51) of the positive current collector (5) has a frame skeleton forming the four sides of a rectangle, and a plurality of middle skeletons connected with the frame skeleton and present at the inner side than the frame skeleton. At least a part of the plurality of longitudinal middle skeletons in the range between the center of the pair of longitudinal frame skeletons (513, 514) and the longitudinal frame skeleton on the side without the tab (11), i.e. the first longitudinal frame skeleton (513), directly reaches the upper frame skeleton (511) by expanding and extending obliquely from the lower frame skeleton side to the upper frame skeleton side. The longitudinal middle skeletons expanding and extending obliquely from the lower frame skeleton side to the upper frame skeleton side all directly reach the upper frame skeleton. The angle between the first longitudinal middle skeleton and the upper frame skeleton on the first longitudinal frame skeleton side is less than 90°, and the connecting point of the first longitudinal middle skeleton with the upper frame skeleton only exists in the above range.

Description

TECHNICAL FIELD

[0001] The present application relates to a liquid lead storage battery. BACKGROUND

[0002] A general liquid lead storage battery has a stack of a plurality of positive electrode plates and a plurality of negative electrode plates, and separators disposed between the positive electrode plates and the negative electrode plates. The positive electrode plate has a positive electrode current collector and a positive electrode mixture including a positive electrode active material containing lead dioxide. The positive electrode current collector has a rectangular grid-shaped base plate and a tab continuous with the grid-shaped base plate, and the positive electrode mixture is held on the grid-shaped base plate. The tabs of the positive electrode current collectors of the plurality of positive electrode plates are connected by a positive electrode connecting plate.

[0003] The negative electrode plate has a negative electrode current collector and a negative electrode mixture including a negative electrode active material containing metallic lead. The negative electrode current collector has a rectangular grid-shaped base plate and a tab continuous with the grid-shaped base plate, and the negative electrode mixture is held on the grid-shaped base plate. The tabs of the negative electrode current collectors of the plurality of negative electrode plates are connected by a negative electrode connecting plate. The positive electrode current collector and the negative electrode current collector are mainly composed of lead or a lead alloy, and the positive electrode mixture and the negative electrode mixture are filled in the opening portions of the grid-shaped base plates.

[0004] As an example of the grid-shaped base plate, a structure having a frame skeleton forming four sides of a rectangle, and a plurality of middle skeletons connected to the frame skeleton and present on an inner side than the frame skeleton can be cited. The frame skeleton has an upper frame skeleton present on an upper side of the grid-shaped base plate and extending in a lateral direction, a lower frame skeleton present on a lower side of the grid-shaped base plate and extending in the lateral direction, and a pair of longitudinal frame skeletons extending in a longitudinal direction. The tab protrudes upward from a position of the upper frame skeleton deviated from a center in a long side direction toward a side close to either of the pair of longitudinal frame skeletons.

[0005] The plurality of middle skeletons have a plurality of longitudinal middle skeletons extending from the upper frame skeleton toward the lower frame skeleton side, and a plurality of lateral middle skeletons connecting the pair of longitudinal frame skeletons. The opening portion in which the positive electrode mixture and the negative electrode mixture are filled is formed only by the middle skeletons, or by the middle skeletons and the frame skeleton. Note that there are also lateral middle skeletons in the lateral middle skeletons that extend only from one of the pair of longitudinal frame skeletons toward the other side or from the other of the pair of longitudinal frame skeletons toward the one side without connecting the pair of longitudinal frame skeletons.

[0006] In recent years, with respect to a liquid lead storage battery for an automobile, the use conditions have become more severe due to an increase in electrical equipment of the automobile and an improvement in fuel efficiency. Therefore, the liquid lead storage battery for an automobile is required to have a performance that can withstand severe use. In particular, idle start-stop vehicles (ISS vehicles) are rapidly spreading, and there is a tendency for the number of starts of the automobile to increase.

[0007] Therefore, in particular, there is a demand for greatly improving the durability of the positive plate compared to the existing product. In order to improve the durability of the positive plate, a paste containing lead powder used in one process of a method of manufacturing the positive plate before formation is improved, and a positive grid body (a grid substrate of a positive current collector) is improved.

[0008] The existing general positive grid body has a simple grid shape in which all of the longitudinal middle frames are orthogonal to the horizontal middle frames. In the case of such a simple grid shape, a portion far from the tab of the positive plate (a portion near the corner portion of the longitudinal frame and the lower frame on the side where the tab is not present: a corner area) has a long path of current compared to other portions, and thus the resistance becomes large. That is, the positive grid body having the simple grid shape has a technical problem in which the potential distribution in the plane is not uniform. Along with this, since the use state of the positive grid body in the plane becomes non-uniform, a state in which delamination, only the portion near the tab is deteriorated (softened), and the life performance is reduced occurs.

[0009] In view of this, in the liquid lead storage battery described in Patent Literature 1, the positive grid body is formed in a shape in which all of the longitudinal middle frames expand in the left and right directions as they are away from the tab. If this shape, the path of current from the corner area to the tab is shorter, and the resistance is smaller compared to the simple grid shape, and thus the potential distribution in the plane becomes good. However, in the case of this shape, the area of the opening portion is larger as it is farther from the tab, and thus, in the case where vibration, impact, and the like are applied in vehicle-mounted use, the active material easily falls off, and the discharge capacity corresponding to the fallen active material is reduced, and thus the life easily decreases.

[0010] In Patent Literature 2, as a grid substrate constituting a current collector of a liquid lead storage battery, a grid body having a shape in which the longitudinal middle frames near the tab side extend perpendicularly with respect to the upper frame and the lower frame, and the longitudinal middle frames other than this extend obliquely in a radial manner from the corner area is described. In addition, in the grid body described in Patent Literature 2, the longitudinal middle frames other than the three longitudinal middle frames near the tab side are connected to the upper frame and the lower frame via the vertically extending longitudinal middle frames. Figure 1 In the grid body described in Patent Literature 2, there are seven longitudinal middle frames that extend in a radial manner, of which three are not in direct contact with the upper frame, but are directly connected to the vertically extending longitudinal middle frames.

[0011] In the liquid lead storage battery having the grid body having such a shape, when a large current is to be taken out in a use such as engine start, according to Kirchhoff's first law, a large current is concentrated in the vertically extending longitudinal middle frames. As a result, in the vertically extending longitudinal middle frames, corrosion rapidly progresses and the resistance increases, and if the corrosion further progresses, there is a possibility that breakage and cracking occur. Along with this, since the current taken out from the longitudinal middle frames that extend in a radial manner is less, there is a possibility that the performance of the battery drastically decreases.

[0012] Prior Art Documents

[0013] Patent Literature

[0014] Patent Literature 1: Japanese Patent Application Laid-Open No. 2019-67522

[0015] Patent Literature 2: Japanese Patent Application Laid-Open No. 2002-42821 SUMMARY

[0016] PROBLEMS TO BE SOLVED BY THE INVENTION

[0017] The technical problem of the present application is to provide a new liquid lead storage battery in which the potential distribution of the positive electrode grid is good and stable performance can be obtained even in applications in which the current taken out is high.

[0018] SOLUTION TO THE PROBLEM

[0019] To solve the above-described technical problem, one embodiment of the present application provides a liquid lead storage battery having the following configurations (1) to (3).

[0020] (1) A liquid lead storage battery including a positive electrode plate having a positive electrode current collector and a positive electrode mixture, in which the positive electrode current collector has a grid-shaped base plate in a rectangular shape, and a tab continuous with the grid-shaped base plate. The positive electrode mixture is held on the grid-shaped base plate. The grid-shaped base plate has a frame skeleton forming four sides of the above-described rectangular shape, and a plurality of middle skeletons connected to the frame skeleton and present on an inner side than the frame skeleton.

[0021] (2) The frame skeleton has an upper frame skeleton present on an upper side of the grid-shaped base plate and extending in a lateral direction, a lower frame skeleton present on a lower side of the grid-shaped base plate and extending in the lateral direction, and a pair of longitudinal frame skeletons extending in a longitudinal direction. The tab protrudes upward from a position deviated from a center in a long side direction of the upper frame skeleton toward one side of either of the pair of longitudinal frame skeletons. The plurality of middle skeletons has a plurality of longitudinal middle skeletons extending from the upper frame skeleton toward the lower frame skeleton side or from the lower frame skeleton toward the upper frame skeleton side, and a plurality of lateral middle skeletons extending from one of the pair of longitudinal frame skeletons toward the other side or from the other of the pair of longitudinal frame skeletons toward the one side.

[0022] (3) At least a part of the plurality of longitudinal middle skeletons present in a range between a center between the pair of longitudinal frame skeletons and a first longitudinal frame skeleton that is a longitudinal frame skeleton on a side on which the tab is not present is a first longitudinal middle skeleton that extends obliquely from the lower frame skeleton side toward the upper frame skeleton side and directly reaches the upper frame skeleton. The longitudinal middle skeletons that extend obliquely from the lower frame skeleton side toward the upper frame skeleton side all directly reach the upper frame skeleton. On the first longitudinal frame skeleton side, an angle formed by the first longitudinal middle skeleton and the upper frame skeleton is less than 90°. The connection point of the first longitudinal middle skeleton with the upper frame skeleton is present only in the above-described range.

[0023] Effects of the Invention

[0024] According to the present application, there is provided a new liquid lead storage battery having a good potential distribution of the positive electrode grid and capable of obtaining stable performance even in applications where a high current is taken out. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a partial cross-sectional view illustrating the structure of a liquid lead storage battery according to an embodiment of the present application.

[0026] Figure 2 is a front view illustrating a positive electrode current collector possessed by a liquid lead storage battery according to a first embodiment of the present application.

[0027] Figure 3 is a view showing the convergence points of lines extending the first longitudinal middle frame in the positive electrode current collector of the first embodiment downward of the lower frame, and the convergence points of lines extending the second longitudinal middle frame upward of the upper frame.

[0028] Figure 4 is a front view illustrating a positive electrode current collector possessed by a liquid lead storage battery according to a second embodiment of the present application.

[0029] Figure 5 is a view showing the convergence points of lines extending the first longitudinal middle frame in the positive electrode current collector of the second embodiment downward of the lower frame, and the convergence points of lines extending the second longitudinal middle frame upward of the upper frame.

[0030] Figure 6 is a front view illustrating a positive electrode current collector possessed by a liquid lead storage battery according to a third embodiment of the present application.

[0031] Figure 7 is a view showing the convergence points of lines extending the first longitudinal middle frame in the positive electrode current collector of the third embodiment downward of the lower frame, and the convergence points of lines extending the second longitudinal middle frame upward of the upper frame.

[0032] Figure 8 is a front view illustrating a positive electrode current collector possessed by a liquid lead storage battery according to a fourth embodiment of the present application.

[0033] Figure 9 is a view showing the convergence points of lines extending the first longitudinal middle frame in the positive electrode current collector of the fourth embodiment downward of the lower frame, and the convergence points of lines extending the second longitudinal middle frame upward of the upper frame.

[0034] Figure 10 is a front view illustrating a positive electrode current collector possessed by a liquid lead storage battery according to a fifth embodiment of the present application.

[0035] Figure 11 This is a diagram showing the convergence point of the line extending from the first vertical frame of the positive current collector in the fifth embodiment to the lower frame, and the convergence point of the line extending from the second vertical frame to the upper frame.

[0036] Figure 12 This is a front view showing the positive current collector of Comparative Example 1.

[0037] Figure 13 This is a front view showing the positive current collector of Comparative Example 2.

[0038] Figure 14 This is a front view showing the positive current collector of Comparative Example 3. Detailed Implementation

[0039] The embodiments of the present invention will now be described; however, the present invention is not limited to the embodiments shown below. The embodiments shown below contain technically preferred limitations for carrying out the present invention; however, these limitations are not essential requirements of the present invention.

[0040] like Figure 1 As shown, the liquid lead-acid battery according to this embodiment includes an electrode assembly 1 consisting of multiple alternating layers of positive electrode plates 10 and negative electrode plates 20 separated by ribbed separators 30. The electrode assembly 1, with its stacking direction along the horizontal direction (i.e., the surfaces of the positive electrode plates 10 and negative electrode plates 20 along the vertical direction), is housed together with an electrolyte (not shown) in a cell chamber of a battery cell 41, and is immersed in the electrolyte within the cell chamber of the battery cell 41. In other words, the liquid lead-acid battery according to this embodiment includes an electrode assembly 1 and a battery cell 41 with cell chambers that house the electrode assembly 1 and the electrolyte. One electrode assembly 1 is housed in one cell chamber, and the number of positive electrode plates 10 constituting the electrode assembly 1 is less than or equal to the number of negative electrode plates 20. It should be noted that the number of positive electrode plates 10 may be the same as or greater than the number of negative electrode plates 20.

[0041] The positive electrode plate 10 has a positive current collector and a positive electrode mixture containing a positive active material, which contains lead dioxide. The positive current collector has a rectangular grid-like substrate and tabs 11 continuous with the grid-like substrate, on which the positive electrode mixture is held. The negative electrode plate 20 has a negative current collector and a negative electrode mixture containing a negative active material, which contains metallic lead. The negative current collector has a rectangular grid-like substrate and tabs 21 continuous with the grid-like substrate, on which the negative electrode mixture is held.

[0042] The positive electrode agent and the negative electrode agent are filled in the openings of each grid-shaped substrate and exist as active material layers on both sides of the grid-shaped substrate.

[0043] The positive current collector will be described in detail later.

[0044] The negative current collector constituting the negative electrode plate 20 is formed by continuous casting. Other manufacturing methods besides continuous casting for the negative current collector include casting with lead alloys, punching for lead alloy rolled sheets, and wire drawing using lead alloy rolled sheets. The separator 30 is, for example, a porous membrane made of resin, glass, etc., having a flat base surface and pleated ribs protruding in a direction orthogonal to the surface direction of the base surface, as needed.

[0045] The tabs 11 of multiple positive plates 10 are connected by positive connecting piece 13, and the tabs 21 of multiple negative plates 20 are connected by negative connecting piece 23. In addition, the positive connecting piece 13 is connected to one end of the positive terminal 15, and the negative connecting piece 23 is connected to one end of the negative terminal 25. The other ends of the positive terminal 15 and the other ends of the negative terminal 25 pass through the cover 43 that blocks the opening of the battery cell 41 and are exposed outside the casing of the liquid lead-acid battery formed by the battery cell 41 and the cover 43.

[0046] Regarding the positive current collector

[0047] First Implementation Method

[0048] Figure 2 A first embodiment of the positive current collector constituting the positive plate 10 is shown. For example... Figure 2 As shown, the positive current collector 5 of the first embodiment has a horizontally elongated rectangular grid-like substrate 51 and electrode tabs 11 continuous with the grid-like substrate, on which a positive electrode binder is held. The grid-like substrate 51 has a frame skeleton forming four sides of a rectangle, and multiple middle frames connected to the frame skeleton and located further inward than the frame skeleton. Furthermore, in the rectangle forming the frame skeleton, the horizontal sides are longer than the vertical sides.

[0049] The frame skeleton has: an upper frame skeleton 511 located on the upper side of the grid-shaped substrate and extending laterally; a lower frame skeleton 512 located on the lower side of the grid-shaped substrate and extending laterally; a left frame skeleton 513 located on the left side of the grid-shaped substrate and extending longitudinally; and a right frame skeleton 514 located on the right side of the grid-shaped substrate and extending longitudinally.

[0050] The tab 11 protrudes upward from a position of the upper frame 511 deviated to the right frame 514 side from the center in the long direction. The plurality of middle frames are constituted by the first longitudinal middle frames 61 to 65 which expand and extend obliquely from the lower frame 512 side toward the upper frame 511 side and directly reach the upper frame 511, the second longitudinal middle frames 71 to 80 which expand and extend obliquely from the upper frame 511 toward the lower frame 512 side, the longitudinal middle frame 516 which extends in parallel with the left frame 513 and the right frame 514 and connects the upper frame 511 and the lower frame 512, and 17 lateral middle frames 517 which connect the left frame 513 and the right frame 514. The lateral middle frames 517 extend in parallel with the upper frame 511 and the lower frame 512.

[0051] The cross-sectional area of the upper frame 511, the left frame 513, and the right frame 514 is larger than the cross-sectional area of the first longitudinal middle frames 61 to 65, the second longitudinal middle frames 71 to 80, the longitudinal middle frame 516, and the lateral middle frames 517.

[0052] Further, the longitudinal middle frames which expand and extend obliquely from the lower frame 512 side toward the upper frame 511 side are only the first longitudinal middle frames 61 to 65, and all directly reach the upper frame 511.

[0053] In Table 1, the distance Ln of the first longitudinal middle frames 61 to 65, the second longitudinal middle frames 71 to 80, and the longitudinal middle frame 516 from the first reference line (a line indicating the position of the center in the width direction of the left frame 513) S1, the ratio Ln / Ls of each distance Ln to the distance (a pair of longitudinal frame distance) Ls of the first reference line S1 to the second reference line (a line indicating the position of the center in the width direction of the right frame 514) S2, and the angle θn of the first longitudinal middle frames 61 to 65, the second longitudinal middle frames 71 to 80, and the longitudinal middle frame 516 with the upper frame 511 on the left frame 513 side are shown. Note that the distance Ls is 135 mm.

[0054] Table 1

[0055]

[0056] The starting points (connection points with the upper frame) of the first longitudinal middle frames 61 to 65 are present all between the center (center line C) between a pair of longitudinal frames (the left frame 513 and the right frame 514) and the left frame (the longitudinal frame on the side where the tab is not present, that is, the first longitudinal frame) 513, and are not present between the center line C and the right frame 514. Further, the range in which the starting points of the first longitudinal middle frames 61 to 65 are present is only between the position from the left frame 513 to 7 / 20 of the pair of longitudinal frame distance Ls (that is, the range to the line C1 which is 0.35 Ls from the first reference line S1).

[0057] On the left frame skeleton 513 side, the angles θ1 to θ5 formed by the first longitudinal middle frames 61-65 and the upper frame skeleton 511 are less than 90°. On the left frame skeleton 513 side, the angles θ6 to θ10 formed by the second longitudinal middle frames 71-75 and the upper frame skeleton 511 are less than 90°, and the angles θ12 to θ16 formed by the second longitudinal middle frames 76-80 and the upper frame skeleton 511 are greater than 90°. The angle θ11 formed by the longitudinal middle frame 516 and the upper frame skeleton 511 is 90°.

[0058] Furthermore, the starting point of the second longitudinal frame 71-80 (the connection point with the upper frame frame) exists only in the range from the right frame frame 514 to the position of 13 / 20 of the distance Ls between the pair of longitudinal frames (that is, the range to the line C1 which is 0.65Ls away from the second baseline S2).

[0059] The first longitudinal central frames 62-65 connect the upper frame frame 511 and the lower frame frame 512 (the first longitudinal central frame 62 extends from the upper frame frame 511 to the corner of the lower frame frame 512 and the left frame frame 513). However, the first longitudinal central frame 61 does not reach the lower frame frame 512 and connects the upper frame frame 511 and the horizontal central frame 517. The second longitudinal central frames 71-78 connect the upper frame frame 511 and the lower frame frame 512. However, the second longitudinal central frames 79 and 80 do not reach the lower frame frame 512 and connect the upper frame frame 511 and the right frame frame 514.

[0060] like Figure 3 As shown, the lines extending downwards from the first vertical frame 61-65, which are further downwards than the lower frame 512, converge to a single point. This convergence point P1 is located further outwards than the extension line L513 of the left frame 513. Furthermore, the lines extending upwards from the second vertical frame 71-80 and the vertical frame 516, which are further upwards than the upper frame 511, converge to a single point. This convergence point P2 is located further inwards than the extension line L514 of the right frame 514 and directly above the vertical frame 516.

[0061] The positive current collector 5 in the first embodiment is formed by punching a rolled sheet made of lead alloy. It should be noted that, in addition to the punching method, other manufacturing methods for the positive current collector include casting of lead alloy and stretching of lead alloy rolled sheet.

[0062] Second Implementation Method

[0063] Figure 4 A second embodiment of the positive current collector constituting the positive electrode plate 10 is shown. The positive current collector of the second embodiment differs from the positive current collector of the first embodiment in the design of the longitudinal frame, but otherwise they are the same.

[0064] like Figure 4As shown, in the positive electrode current collector 5 of the second embodiment, the plurality of middle frames are composed of the first longitudinal middle frames 61 to 66 which expand and extend obliquely from the lower frame 512 side toward the upper frame 511 side and directly reach the upper frame 511, the second longitudinal middle frames 71 to 80 which expand and extend obliquely from the upper frame 511 toward the lower frame 512 side, and the 17 lateral middle frames 517 which connect the left frame 513 and the right frame 514. The lateral middle frames 517 extend in parallel with the upper frame 511 and the lower frame 512.

[0065] The cross-sectional area of the upper frame 511, the left frame 513, and the right frame 514 is larger than that of the first longitudinal middle frames 61 to 66, the second longitudinal middle frames 71 to 80, and the lateral middle frames 517.

[0066] Further, the longitudinal middle frames which expand and extend obliquely from the lower frame 512 side toward the upper frame 511 side are only the first longitudinal middle frames 61 to 66, and all of them directly reach the upper frame 511.

[0067] Table 2 shows the distance Ln of the first longitudinal middle frames 61 to 66 and the second longitudinal middle frames 71 to 80 from the first reference line (a line indicating the width direction center position of the left frame 513) S1, the ratio Ln / Ls of each distance Ln to the distance (a pair of longitudinal frame distance) Ls of the first reference line S1 to the second reference line (a line indicating the width direction center position of the right frame 514) S2, and the angle θn of the first longitudinal middle frames 61 to 66 and the second longitudinal middle frames 71 to 80 on the left frame 513 side from the upper frame 511. Note that the distance Ls is 135 mm.

[0068] Table 2

[0069]

[0070] The starting points (connection points with the upper frame) of the first longitudinal middle frames 61 to 66 are present all between the center (center line C) between a pair of longitudinal frames (the left frame 513 and the right frame 514) and the left frame 513 (the longitudinal frame on the side where the tab is not present, i.e., the first longitudinal frame), and are not present between the center line C and the right frame 514. Further, the range in which the starting points of the first longitudinal middle frames 61 to 66 are present is only from the left frame 513 to a position 9 / 20 of the pair of longitudinal frame distance Ls (that is, to the range of a line C1 which is 0.45 Ls from the first reference line S1).

[0071] On the left frame frame 513 side, the angles θ1 to θ6 formed by the first longitudinal middle frames 61 to 66 and the upper frame frame 511 are less than 90°. On the left frame frame 513 side, the angles θ7 to θ12 formed by the second longitudinal middle frames 71 to 76 and the upper frame frame 511 are less than 90°, and the angles θ13 to θ16 formed by the second longitudinal middle frames 77 to 80 and the upper frame frame 511 are greater than 90°.

[0072] Furthermore, the starting point of the second longitudinal frame 71-80 (the connection point with the upper frame frame) exists only in the range from the right frame frame 514 to the position of 11 / 20 of the distance Ls between the pair of longitudinal frames (that is, the range to the line C1 which is 0.55Ls away from the second baseline S2).

[0073] The first longitudinal central frames 63-66 connect the upper frame frame 511 and the lower frame frame 512. However, the first longitudinal central frames 61 and 62 do not reach the lower frame frame 512, but connect the upper frame frame 511 and the horizontal central frame 517. The second longitudinal central frames 71-78 connect the upper frame frame 511 and the lower frame frame 512. However, the second longitudinal central frames 79 and 80 do not reach the lower frame frame 512, but connect the upper frame frame 511 and the horizontal central frame 517.

[0074] like Figure 5 As shown, the lines extending downwards from the first vertical frame 61-66 compared to the lower frame 512 converge to a single point. This convergence point P1 is located further outwards than the extension line L513 of the left frame 513. Furthermore, the lines extending upwards from the second vertical frame 71-80 compared to the upper frame 511 converge to a single point. This convergence point P2 is located further inwards than the extension line L514 of the right frame 514.

[0075] Third Implementation Method

[0076] Figure 6 A third embodiment of the positive current collector constituting the positive electrode plate 10 is shown. The positive current collector of the third embodiment differs from the positive current collector of the first embodiment in the design of the longitudinal frame, but otherwise they are the same.

[0077] like Figure 6 As shown, in the positive current collector 5 of the third embodiment, the multiple central frames consist of a first longitudinal central frame 61-66 that extends obliquely from the lower frame 512 side toward the upper frame 511 side and directly reaches the upper frame 511; a second longitudinal central frame 71-77 that extends obliquely from the upper frame 511 toward the lower frame 512 side; a reinforcing frame 91; and 17 transverse central frames 517 connecting the left frame 513 and the right frame 514. The transverse central frames 517 extend parallel to the upper frame 511 and the lower frame 512.

[0078] The cross-sectional area of the upper frame skeleton 511, the left frame skeleton 513, and the right frame skeleton 514 is larger than that of the first longitudinal middle skeletons 61 to 66, the second longitudinal middle skeletons 71 to 77, the lateral middle skeleton 517, and the reinforcing skeleton 91.

[0079] Further, the longitudinal middle skeletons that expand and extend obliquely from the lower frame skeleton 512 side toward the upper frame skeleton 511 side are only the first longitudinal middle skeletons 61 to 66, and all of them directly reach the upper frame skeleton 511.

[0080] Table 3 shows the distance Ln of the first longitudinal middle skeletons 61 to 66 and the second longitudinal middle skeletons 71 to 77 from the first reference line (a line indicating the width direction center position of the left frame skeleton 513) S1, the ratio Ln / Ls of each distance Ln to the distance (a pair of longitudinal frame skeletons distance) Ls of the first reference line S1 and the second reference line (a line indicating the width direction center position of the right frame skeleton 514) S2, and the angle θn of the first longitudinal middle skeletons 61 to 66 and the second longitudinal middle skeletons 71 to 77 from the upper frame skeleton 511 on the left frame skeleton 513 side. Note that the distance Ls is 135 mm.

[0081] Table 3

[0082]

[0083] The start points (connection points with the upper frame skeleton) of the first longitudinal middle skeletons 61 to 66 are present all between the center (center line C) between a pair of longitudinal frame skeletons (the left frame skeleton 513 and the right frame skeleton 514) and the left frame skeleton (a longitudinal frame skeleton on which no tab is present, that is, the first longitudinal frame skeleton) 513, and are not present between the center line C and the right frame skeleton 514. Further, the range in which the start points of the first longitudinal middle skeletons 61 to 66 are present is only from the left frame skeleton 513 to a position 9 / 20 of the pair of longitudinal frame skeletons distance Ls (that is, to the range of a line C1 at a distance of 0.45 Ls from the reference line S1).

[0084] On the left frame skeleton 513 side, the angles θ1 to θ6 of the first longitudinal middle skeletons 61 to 66 from the upper frame skeleton 511 are smaller than 90°. On the left frame skeleton 513 side, the angles θ7 to θ13 of the second longitudinal middle skeletons 71 to 77 from the upper frame skeleton 511 are smaller than 90°. On the left frame skeleton 513 side, the angle θ91 of the reinforcing skeleton 91 from the lateral middle skeleton 517 is larger than θ13 and smaller than 90°.

[0085] Further, the range in which the start points of the second longitudinal middle skeletons 71 to 77 are present is only from the right frame skeleton 514 to a position 11 / 20 of the pair of longitudinal frame skeletons distance Ls (that is, to the range of a line C1 at a distance of 0.55 Ls from the second reference line S2).

[0086] The first longitudinal central frame 61-66 are all connected to the upper frame frame 511 and the lower frame frame 512. The second longitudinal central frame 71-77 are all connected to the upper frame frame 511 and the lower frame frame 512. The reinforcing frame 91 connects the lower frame frame 512 and the horizontal central frame 517.

[0087] like Figure 7 As shown, the lines extending downwards from the first longitudinal frame 61-66 compared to the lower frame 512 converge to a single point. This convergence point P1 is located further inwards than the extension line L513 of the left frame 513. Furthermore, the lines extending upwards from the second longitudinal frame 71-77 and the reinforcing frame 91 compared to the upper frame 511 converge to a single point. This convergence point P2 is located further outwards than the extension line L514 of the right frame 514.

[0088] Fourth Implementation Method

[0089] Figure 8 A fourth embodiment of the positive current collector constituting the positive electrode plate 10 is shown. The positive current collector of the fourth embodiment differs from the positive current collector of the first embodiment in the design of its longitudinal frame, but otherwise they are identical.

[0090] like Figure 8 As shown, in the positive current collector 5 of the fourth embodiment, the multiple central frames consist of a first longitudinal central frame 61-66 that extends obliquely from the lower frame frame 512 towards the upper frame frame 511 and directly reaches the upper frame frame 511; a second longitudinal central frame 71-77 that extends obliquely from the upper frame frame 511 towards the lower frame frame 512; a reinforcing frame 91; and 17 transverse central frames 517 connecting the left frame frame 513 and the right frame frame 514. The transverse central frames 517 extend parallel to the upper frame frame 511 and the lower frame frame 512.

[0091] The cross-sectional areas of the upper frame skeleton 511, the left frame skeleton 513, and the right frame skeleton 514 are greater than the cross-sectional areas of the first longitudinal central skeleton 61-66, the second longitudinal central skeleton 71-77, the horizontal central skeleton 517, and the reinforcing skeleton 91.

[0092] Furthermore, the longitudinal central skeletons that extend obliquely from the lower frame skeleton 512 side toward the upper frame skeleton 511 side are only the first longitudinal central skeletons 61 to 66, and all of them directly reach the upper frame skeleton 511.

[0093] Table 4 shows the distance Ln of the first longitudinal middle frames 61 to 66 and the second longitudinal middle frames 71 to 77 from the first reference line (a line indicating the width direction center position of the left frame 513) S1, the ratio Ln / Ls of each distance Ln to the distance (a pair of longitudinal frame distance) Ls of the first reference line S1 and the second reference line (a line indicating the width direction center position of the right frame 514) S2, and the angle θn of the first longitudinal middle frames 61 to 66 and the second longitudinal middle frames 71 to 77 with the upper frame 511 on the left frame 513 side. Note that the distance Ls is 135 mm.

[0094] Table 4

[0095]

[0096] The starting points (connection points with the upper frame) of the first longitudinal middle frames 61 to 66 are present all between the center (center line C) between a pair of longitudinal frames (the left frame 513 and the right frame 514) and the left frame 513 (a longitudinal frame on the side where the tab is not present, i.e., the first longitudinal frame), and are not present between the center line C and the right frame 514. Furthermore, the range in which the starting points of the first longitudinal middle frames 61 to 66 are present is only between the left frame 513 and a position 9 / 20 of the pair of longitudinal frame distance Ls (i.e., the range to the line C1 at a distance of 0.45 Ls from the reference line S1).

[0097] Furthermore, on the left frame 513 side, the angles θ1 to θ6 of the first longitudinal middle frames 61 to 66 with the upper frame 511 are 90° or less. On the left frame 513 side, the angle θ91 of the reinforcing frame 91 with the horizontal middle frame 517 is larger than θ13 and smaller than 90°.

[0098] Furthermore, the range in which the starting points of the second longitudinal middle frames 71 to 77 are present is only between the right frame 514 and a position 11 / 20 of the pair of longitudinal frame distance Ls (i.e., the range to the line C1 at a distance of 0.55 Ls from the second reference line S2).

[0099] The first longitudinal middle frames 61 to 66 are all connected to the upper frame 511 and the lower frame 512. The second longitudinal middle frames 71 to 77 are connected to the upper frame 511 and the lower frame 512. The reinforcing frame 91 is connected to the lower frame 512 and the horizontal middle frame 517.

[0100] As Figure 9As shown, lines that make the first longitudinal middle frames 61 to 66 extend more downward than the lower frame 512 converge at one point. The convergence point Pl is located more outward than the extension line L513 of the left frame 513. Further, lines that make the second longitudinal middle frames 71 to 77 and the reinforcing frame 91 extend more upward than the upper frame 511 converge at one point. The convergence point P2 is located more outward than the extension line L514 of the right frame 514.

[0101] Fifth Embodiment

[0102] Figure 10 A fifth embodiment of a positive electrode current collector that constitutes the positive electrode plate 10 is shown. The positive electrode current collector of the fifth embodiment differs from the positive electrode current collector of the first embodiment in the design of the longitudinal middle frames, but is otherwise the same.

[0103] As Figure 10 shown, in the positive electrode current collector 5 of the fifth embodiment, the plurality of middle frames are constituted by the first longitudinal middle frames 61 to 66 that expand obliquely from the lower frame 512 side toward the upper frame 511 side and extend directly to the upper frame 511, the second longitudinal middle frames 71 to 80 that expand obliquely from the upper frame 511 toward the lower frame 512 side and extend, and the 17 lateral middle frames 517 that connect the left frame 513 and the right frame 514. The lateral middle frames 517 extend in parallel with the upper frame 511 and the lower frame 512.

[0104] The cross-sectional areas of the upper frame 511, the left frame 513, and the right frame 514 are larger than those of the first longitudinal middle frames 61 to 66, the second longitudinal middle frames 71 to 80, and the lateral middle frames 517.

[0105] Further, the longitudinal middle frames that expand obliquely from the lower frame 512 side toward the upper frame 511 side are only the first longitudinal middle frames 61 to 66, and all of them directly reach the upper frame 511.

[0106] Table 5 shows the distances Ln of the first longitudinal middle frames 61 to 66 and the second longitudinal middle frames 71 to 80 from a first reference line (a line that indicates the widthwise center position of the left frame 513) SI, the ratios Ln / Ls of each distance Ln to the distance (a pair of longitudinal frame distance) Ls of the first reference line SI to a second reference line (a line that indicates the widthwise center position of the right frame 514) S2, and the angles θn that the first longitudinal middle frames 61 to 66 and the second longitudinal middle frames 71 to 80 on the left frame 513 side make with the upper frame 511. Note that the distance Ls is 135 mm.

[0107] Table 5

[0108]

[0109] The starting points of the first longitudinal frames 61-66 (the connection points with the upper frame frame) are all located between the center line C between the pair of longitudinal frames (left frame frame 513 and right frame frame 514) and the left frame frame (the longitudinal frame frame without the tabs, i.e., the first longitudinal frame frame) 513, and not between the center line C and the right frame frame 514. Furthermore, the starting points of the first longitudinal frames 61-66 exist only within the range from the left frame frame 513 to 9 / 20 of the distance Ls between the pair of longitudinal frames (that is, the range to line C1, which is 0.45Ls away from the baseline S1).

[0110] Furthermore, on the left frame frame 513 side, the angles θ1 to θ6 formed by the first longitudinal middle frame 61 to 66 and the upper frame frame 511 are less than 90°.

[0111] Furthermore, the starting point of the second longitudinal frame 71-80 exists only in the range from the right frame frame 514 to the position of 11 / 20 of the distance Ls between a pair of longitudinal frames (that is, the range to the line C1 which is 0.55Ls away from the second baseline S2).

[0112] The first longitudinal central skeleton 61-66 are all connected to the upper frame skeleton 511 and the lower frame skeleton 512. The second longitudinal central skeleton 71-78 are connected to the upper frame skeleton 511 and the lower frame skeleton 512. However, the second longitudinal central skeleton 79 and 80 do not reach the lower frame skeleton 512, but are connected to the upper frame skeleton 511 and the horizontal central skeleton 517.

[0113] like Figure 11 As shown, the lines extending downwards from the first vertical frame 61-66 compared to the lower frame 512 converge to a single point. This convergence point P1 is located further inside than the extension line L513 of the left frame 513. Furthermore, the lines extending upwards from the second vertical frame 71-80 compared to the upper frame 511 converge to a single point. This convergence point P2 is located further inside than the extension line L514 of the right frame 514.

[0114] Comparative Example 1

[0115] exist Figure 12In the positive electrode current collector 50 of Comparative Example 1 shown, the plurality of middle frames are composed of 16 longitudinal middle frames 516 connecting the upper frame 511 and the lower frame 512, and 17 transverse middle frames 517 connecting the left frame 513 and the right frame 514. The longitudinal middle frames 516 extend in parallel with the left frame 513 and the right frame 514. That is, in this example, there is no first longitudinal middle frame which expands obliquely from the lower frame 512 side toward the upper frame 511 side and extends directly to the upper frame 511, and there is no second longitudinal middle frame which expands obliquely from the upper frame 511 toward the lower frame 512 side. The transverse middle frames 517 extend in parallel with the upper frame 511 and the lower frame 512.

[0116] The cross-sectional area of the upper frame 511, the left frame 513, and the right frame 514 is larger than the cross-sectional area of the longitudinal middle frames 516 and the transverse middle frames 517.

[0117] Table 6 shows the distance Ln of the 16 longitudinal middle frames 516 from a first reference line (a line indicating the width direction center position of the left frame 513) S1, the ratio Ln / Ls of each distance Ln to the distance (a pair of longitudinal frame distance) Ls of the first reference line S1 to a second reference line (a line indicating the width direction center position of the right frame 514) S2, and the angle θn (all 90°) of the longitudinal middle frame 516 on the left frame 513 side to the upper frame 511. Note that the distance Ls is 135 mm.

[0118] Table 6

[0119]

[0120] Comparative Example 2

[0121] In Figure 13 In the positive electrode current collector 50A of Comparative Example 2 shown, the plurality of middle frames are composed of the second longitudinal middle frames 71 to 85 which expand obliquely from the upper frame 511 toward the lower frame 512 side and extend, the longitudinal middle frames 516 which extend in parallel with the left frame 513 and the right frame 514 and connect the upper frame 511 and the lower frame 512, and the 17 transverse middle frames 517 which connect the left frame 513 and the right frame 514. That is, in this example, there is no first longitudinal middle frame which expands obliquely from the lower frame 512 side toward the upper frame 511 side and extends directly to the upper frame 511. The transverse middle frames 517 extend in parallel with the upper frame 511 and the lower frame 512.

[0122] The cross-sectional area of the upper frame 511, the left frame 513, and the right frame 514 is larger than the cross-sectional area of the longitudinal middle frames 516, the second longitudinal middle frames 71 to 85, and the transverse middle frames 517.

[0123] Table 7 shows the distance Ln of the second middle longitudinal frames 71 to 85 from the first reference line (a line indicating the widthwise center position of the left frame 513) SI, the ratio Ln / Ls of each distance Ln to the distance (a pair of longitudinal frame interval distance) Ls of the first reference line SI from the second reference line (a line indicating the widthwise center position of the right frame 514) S2, and the angle θn of the second middle longitudinal frames 71 to 85 with the upper frame 511 on the left frame 513 side. Note that the distance Ls is 135 mm.

[0124] Table 7

[0125]

[0126] The starting points (connection points with the upper frame) of the second middle longitudinal frames 71 to 85 are also present in a range further outward from the right frame 514 to a position of 11 / 20 of the pair of longitudinal frame interval distance Ls (that is, a line CI at a distance of 0.55 Ls from the second reference line S2).

[0127] Further, on the left frame 513 side, the angles θ1 to θ11, θ13 to θ16 of the second middle longitudinal frames 71 to 85 with the upper frame 511 are less than 90°.

[0128] The second middle longitudinal frames 74 to 84 connect the upper frame 511 and the lower frame 512, the second middle longitudinal frames 71 to 73 connect the upper frame 511 and the left frame 513, and the second middle longitudinal frame 85 connects the upper frame 511 and the right frame 514.

[0129] The lines that extend the second middle longitudinal frames 71 to 85 and the middle longitudinal frame 516 upward more than the upper frame 511 converge at a point on the extension line of the middle longitudinal frame 516. That is, the converging point is located between the extension line of the left frame 513 and the extension line of the right frame 514 (directly above the tab 11).

[0130] Comparative Example 3

[0131] In Figure 14In the positive electrode current collector 50B shown, the plurality of middle frames are composed of the first longitudinal middle frames 61 to 64 which expand obliquely from the lower frame 512 side toward the upper frame 511 side and extend directly to the upper frame 511, the 9 longitudinal middle frames 516 which extend parallel to the left frame 513 and the right frame 514 and connect the upper frame 511 and the lower frame 512, the reinforcing frames 92 to 94 which expand obliquely from the lower frame 512 side toward the upper frame 511 side and extend to the longitudinal middle frames 516A closest to the left frame 513, and the 17 transverse middle frames 517 which connect the left frame 513 and the right frame 514. The transverse middle frames 517 extend parallel to the upper frame 511 and the lower frame 512.

[0132] That is, in this example, there are no second longitudinal middle frames which expand obliquely from the upper frame 511 side toward the lower frame 512 side and extend. Further, as longitudinal middle frames which expand obliquely from the lower frame 512 side toward the upper frame 511 side, in addition to the first longitudinal middle frames 61 to 64 which extend directly to the upper frame 511, there are the reinforcing frames 92 to 94 which do not extend directly to the upper frame 511 but to the longitudinal middle frames 516A.

[0133] The cross-sectional area of the upper frame 511, the left frame 513, and the right frame 514 is larger than that of the 9 longitudinal middle frames 516, the first longitudinal middle frames 61 to 64, the reinforcing frames 92 to 94, and the transverse middle frames 517.

[0134] Table 8 shows the distance Ln of the first longitudinal middle frames 61 to 64 and the longitudinal middle frames 516 from a first reference line (a line indicating the widthwise center position of the left frame 513) S1, the ratio Ln / Ls of each distance Ln to the distance (a pair of longitudinal frame distance) Ls of the first reference line S1 to a second reference line (a line indicating the widthwise center position of the right frame 514) S2, and the angle θn of the first longitudinal middle frames 61 to 64 and the longitudinal middle frames 516 on the left frame 513 side to the upper frame 511 (the angle of the longitudinal middle frames 516 to the upper frame 511 is all 90°). Note that the distance Ls is 135 mm.

[0135] Table 8

[0136]

[0137] The starting points (connection points with the upper frame) of the first longitudinal middle frames 61 to 64 are present in the range from the left frame 513 to a position 9 / 20 of the distance Ls between the pair of longitudinal frames (that is, in the range of the line C1 which is 0.45Ls from the first reference line S1) and are not present in the range from the center line C to the right frame 514. In addition, the starting points of the first longitudinal middle frames 61 to 64 are present in the range from the left frame 513 to a position 9 / 20 of the distance Ls between the pair of longitudinal frames (that is, in the range of the line C1 which is 0.45Ls from the first reference line S1).

[0138] On the left frame 513 side, the angles θ1 to θ4 formed by the first longitudinal middle frames 61 to 64 and the upper frame 511 are less than 90°. On the left frame 513 side, the angles θ92 to θ94 formed by the reinforcing frames 92 to 94 and the horizontal middle frame 517 are less than 90° and are less than θ4.

[0139] Effects of the liquid lead storage battery according to the embodiment

[0140] The positive current collector according to the first to fifth embodiments satisfies all of the following (a) to (d).

[0141] (a) At least a part of the plurality of longitudinal middle frames present in the range between the center between the pair of longitudinal frames and the longitudinal frame on the side on which the tab is not present, that is, the first longitudinal frame, is a first longitudinal middle frame which expands and extends obliquely from the lower frame side toward the upper frame side and directly reaches the upper frame.

[0142] (b) The longitudinal middle frames which expand and extend obliquely from the lower frame side toward the upper frame side all directly reach the upper frame.

[0143] (c) On the first longitudinal frame side, the angle formed by the first longitudinal middle frame and the upper frame is less than 90°. That is, the first longitudinal middle frame expands toward the direction close to the tab.

[0144] (d) The connection points of the first longitudinal middle frame with the upper frame are present only in the range between the center between the pair of longitudinal frames and the longitudinal frame on the side on which the tab is not present, that is, the first longitudinal frame.

[0145] The positive current collector of Comparative Example 1 does not satisfy all of (a) to (d) above. The positive current collector of Comparative Example 2 does not satisfy all of (a) to (d) above. Comparative Example 2 is a liquid lead-acid battery described in Patent Document 1, wherein the positive grid is formed in a shape in which the spacing of the entire longitudinal frame expands in the left and right directions as it moves away from the tab. Compared with the positive current collector of Comparative Example 1, the positive current collector of Comparative Example 2 has a better in-plane potential distribution; however, the area of ​​the opening increases further away from the tab. Therefore, under conditions of vibration and impact, such as during vehicle use, the discharge capacity corresponding to the amount of active material shed decreases, and thus the lifespan is easily reduced.

[0146] The positive current collector of Comparative Example 3 does not satisfy the above (b). The positive current collector of Comparative Example 3 is the grid body described in Patent Document 2. In a liquid lead-acid battery with this grid body, if a large current is to be drawn in applications such as engine starting, as described above, the large current is concentrated in the longitudinal frame 516A, which leads to corrosion and may cause a sharp decrease in battery performance.

[0147] In view of this, the positive current collectors of the first to fifth embodiments satisfy all of the above (a) to (d), thereby making the potential distribution of the positive grid body good and achieving stable performance even in applications with high extraction current.

[0148] In cases where (c) above is not met (e.g., in relation to...) Figure 7 In the case where the convergence point P1 is significantly closer to the right side than the convergence point P1, the first longitudinal frame extends away from the tab 11, thus making it difficult to improve the potential distribution. On the first longitudinal frame side, it is preferable that the angle between the first longitudinal frame and the upper frame is 45° or more and less than 90°, more preferably 70° or more and less than 90°.

[0149] Furthermore, the starting point of the first longitudinal frame exists only within a range from the left frame 513 to 9 / 20 of the distance Ls between the pair of longitudinal frames (that is, satisfying the above (d)), and the starting point of the second longitudinal frame (the connection point with the upper frame) exists only within a range from the right frame 514 to 11 / 20 of the distance Ls between the pair of longitudinal frames. Therefore, in a typical configuration density, the opening formed by the longitudinal frame, frame, and transverse frame on the side extending from the first and second longitudinal frames is of a suitable size, thus avoiding adverse conditions such as the need for reinforcing frames. If the opening becomes larger, reinforcing frames are required, which complicates the manufacturing process and increases the weight of the positive current collector.

[0150] Preferably, the starting point of the first vertical frame exists in the range between 1 / 5 and 1 / 2 of the distance Ls between the left frame frame 513 and the pair of vertical frames.

[0151] Further, since there are convergence points PI, P2, that is, since the line that extends the first longitudinal middle skeleton more downward than the lower frame skeleton 512 converges at a point, and the line that extends the second longitudinal middle skeleton more upward than the upper frame skeleton 511 converges at a point, the potential distribution becomes good compared to the case where there is no convergence. Further, since the design change becomes easy, it is also possible to easily cope with the expansion of the product to a plurality of types.

[0152] Moreover, in the case where the oblong shape of the frame skeleton that forms the positive electrode current collector is "longer in the lateral direction than in the longitudinal direction", the growth of the grid-shaped substrate of the positive electrode current collector in the lateral direction tends to be large. In addition, if the growth in the lateral direction progresses, the frame skeletons on the left and right of the expanded positive electrode plate stretch the separators in contact, and sometimes tear them. Even if it does not reach the extent of tearing the separators, a part of the positive electrode grid that is damaged due to corrosion sometimes pierces the separators. As a result, the positive electrode and the negative electrode that are stacked on each other through the separators come into contact and short-circuit, and sometimes reach the life span prematurely.

[0153] In the positive electrode current collectors of the first to fifth embodiments, the grid-shaped substrate of the positive electrode current collector is in a long shape, but all of (a) to (d) described above are satisfied, so that a significant potential distribution improvement effect can be obtained, and it is possible to prevent the life span from being reached prematurely.

[0154] In comparison with Comparative Example 3, in the skeleton that expands and extends obliquely from the lower frame skeleton toward the upper frame skeleton, the number of the first longitudinal middle skeletons directly connected to the upper frame skeleton is larger in the positive electrode current collector 5 of the first to fifth embodiments than in the positive electrode current collector 50B of Comparative Example 3, and therefore, the amount of current collection toward the upper frame skeleton having a large cross-sectional area is larger, and thus, corrosion is less likely to occur in the longitudinal middle skeletons.

[0155] Note that the first longitudinal middle skeletons 61 that constitute the positive electrode current collector of the first embodiment, and the first longitudinal middle skeletons 61, 62 that constitute the positive electrode current collectors of the second and fourth embodiments do not reach the lower frame skeleton 512, but it is preferable that the first longitudinal middle skeletons all reach the lower frame skeleton 512, or even in the case where they do not reach the lower frame skeleton 512, they reach a position that is 0.90 times or more the distance from the upper frame skeleton 511 and the lower frame skeleton 512. Thereby, the effect of improving the potential distribution is improved throughout the surface of the positive electrode current collector.

[0156] Further, the differences in the effects and the like due to the designs of the longitudinal middle skeletons in the positive electrode current collectors of the first to fifth embodiments are as described below.

[0157] In the lead storage battery using the positive electrode current collector of the first embodiment and the second embodiment, the second longitudinal middle frames are concentrated toward the upper side of the tab, and thus, as compared with the third embodiment and the fourth embodiment, excellent current collecting properties and cycle life properties can be obtained.

[0158] In the comparison between the first embodiment and the second embodiment, the range in which the starting point of the first longitudinal middle frame exists is smaller in the first embodiment than in the second embodiment, between the left frame 513 and a position 7 / 20 of the distance Ls between the pair of longitudinal frames, and the range in which the starting point of the second longitudinal middle frame exists is larger in the first embodiment than in the second embodiment, between the right frame 514 and a position 13 / 20 of the distance Ls between the pair of longitudinal frames. Thus, in the normal arrangement density, the opening portion composed of the longitudinal middle frame, the frame, and the horizontal middle frame formed on the extension side of the first longitudinal middle frame and the second longitudinal middle frame is of a more moderate size in the first embodiment than in the second embodiment, and thus, the first embodiment is more advantageous in that no adverse situation caused by the arrangement of the reinforcing frame or the like occurs.

[0159] In the lead storage battery using the positive electrode current collector of the third embodiment, the average opening area of the opening portion formed by the first longitudinal middle frame is smaller than that of the other embodiments, and thus, peeling and falling of the positive electrode mixture held in the opening portion are easily prevented, but the average opening area of the opening portion in the vicinity of the tab becomes larger than that of the first embodiment and the second embodiment, and thus, the current collecting properties and the cycle life properties are slightly worse than those of the first embodiment and the second embodiment.

[0160] The lead storage battery using the positive electrode current collector of the fourth embodiment has a smaller variation in the opening area of the opening portion than the first to third embodiments, and thus, peeling and falling of the positive electrode mixture in a local portion are easily prevented, but the cycle life properties for the idle start and stop vehicle are slightly worse than those of the first to third embodiments.

[0161] The lead storage battery using the positive electrode current collector of the fifth embodiment has the second longitudinal middle frames concentrated toward the upper side of the tab like the first embodiment and the second embodiment, and thus, excellent current collecting properties and cycle life properties can be obtained as compared with the third embodiment and the fourth embodiment. Further, the lead storage battery using the positive electrode current collector of the fifth embodiment has the average opening area of the opening portion formed by the first longitudinal middle frame smaller than that of the other embodiments like the third embodiment, and thus, peeling and falling of the positive electrode mixture held in the opening portion are easily prevented.

[0162] Preferred Mode 1

[0163] Preferably, in the positive electrode current collector of the first to fifth embodiments, the cross-sectional area of the upper frame 511 is 235% to 300% relative to the average cross-sectional area of the lateral middle frames 517, and the respective opening areas of the plurality of opening portions that are connected to the upper frame 511, when viewed from above, are 50% to 75% relative to the average opening area of all the opening portions of the grid-shaped substrate 51.

[0164] Preferred Mode 2

[0165] Preferably, in the positive electrode current collector of the first to fifth embodiments, in the case where the positive electrode mixture is porous, the average diameter of the fine pores of the positive electrode mixture is 0.15 μm or more and 0.40 μm or less, and the porosity of the positive electrode mixture is 30% or more and 50% or less.

[0166] If the diameter of the fine pores of the positive electrode mixture is less than 0.15 μm, there is a possibility that the utilization rate of the positive electrode active material decreases. On the other hand, if the average diameter of the fine pores of the positive electrode mixture is more than 0.40 μm, there is a possibility that the internal resistance of the lead storage battery increases. Furthermore, there is a possibility that softening of the positive electrode mixture easily occurs. The method of measuring the average diameter of the fine pores of the positive electrode mixture is not particularly limited, but, for example, the mercury porosimetry can be used.

[0167] If the porosity of the positive electrode mixture is less than 30%, it is difficult for sulfuric acid to penetrate into the mixture, and there is a possibility that the utilization rate of the active material decreases. On the other hand, if the porosity of the positive electrode mixture is more than 50%, the density of the mixture decreases, and thus there is a possibility that the cycle life decreases.

[0168] Preferred Mode 3

[0169] Preferably, in the positive electrode current collector of the first embodiment, the cross-sectional area of the second lateral middle frames 74 to 76 and the lateral middle frame 516 that are connected to the lower portion of the tab 11 is 1.26 times or more and 1.50 times or less relative to the average cross-sectional area of all the lateral middle frames.

[0170] Example

[0171] With respect to the preferred modes 1 to 3, the following examples and comparative examples are shown to make a more specific description.

[0172] Comparative Test with Respect to Preferred Mode 1

[0173] The lead storage batteries (sample Nos. 1 to 25) of a battery size of Q-85 were produced by the following method. As shown in Table 1, the lead storage batteries of sample Nos. 1 to 25 were different from each other in the configuration of the upper frame of the positive electrode current collector and the opening portion connected to the upper frame, but were the same in other points. When the utilization of the active material was measured by the following method, the utilization of the active material was measured by the following method. Figure 2In the description, for samples No. 1 to No. 25, the width (lateral dimension) and height (vertical dimension) of the grid-shaped substrate 51 in the positive electrode current collector 5 are 135 mm and 114.5 mm, respectively. These dimensions refer to the spacing between the center lines of the frame skeleton. The cross-sectional area of ​​the left frame skeleton 513, right frame skeleton 514, and lower frame skeleton 512 is 1.80 mm². 2 .

[0174] First, current collectors (grid-shaped substrate + tabs) for positive and negative electrodes were fabricated from rolled sheets made of Pb-Ca-Sn alloy by a punching method. In the cross-section obtained by cutting the current collector in the thickness direction, a rolled microstructure with an average interlayer distance of 20 μm was observed.

[0175] Each positive current collector weighs 40.0g. When various changes were made to the thickness ratio of the upper frame 511, the thickness of the frame was also changed simultaneously to make the weight of the positive current collector the same across all samples.

[0176] The positive electrode current collector of samples No.1 to No.5 of the liquid lead-acid batteries is in Figure 2 In the positive current collector 5, all the transverse frame 517 have the same thickness. In the positive current collectors of samples No.1 to No.5, the average cross-sectional area of ​​all the transverse frame 517 is 1.00 mm². 2 The average cross-sectional area of ​​the upper frame skeleton 511 is 2.00 mm². 2 The opening areas when viewed from above, specifically those connecting to the upper frame 511, are 45%, 50%, 65%, 75%, and 80% of the average opening area when all openings are viewed from above. The average opening area of ​​the openings connecting to the upper frame 511 is adjusted by changing the separation distance between the horizontal mid-frames 517. At this point, the separation distance between the horizontal mid-frames 517 is adjusted to be equal for each other.

[0177] In the positive electrode current collector 5 of the liquid lead-acid batteries in samples No. 6 to No. 10, the cross-sectional area of ​​the upper frame skeleton 511 constituting the grid-shaped substrate 51 is 2.23 mm². 2 The cross-sectional area of ​​the entire horizontal frame 517 is 0.95 mm². 2 That is, the thickness ratio of the upper frame skeleton 511 to the horizontal center skeleton 517 is 235%. The average opening area when viewed from above at the openings connected to the upper frame skeleton 511 is 45%, 50%, 65%, 75%, and 80% of the average opening area when viewed from above at all openings, respectively. The average opening area of ​​the openings connected to the upper frame skeleton 511 is adjusted by changing the separation distance between the horizontal center skeletons 517. At this time, the separation distance between the horizontal center skeletons 517 is adjusted to be equal for each other.

[0178] In the positive electrode current collector 5 of the liquid lead storage battery of Sample Nos. 11 to 15, the upper frame skeleton 511 constituting the lattice-shaped substrate 51 has a cross-sectional area of 2.43 mm 2 , and all the cross-sectional areas of the lateral middle skeletons 517 are 0.90 mm 2 . That is, the thickness ratio of the upper frame skeleton 511 to the lateral middle skeletons 517 is 270%. The average opening area of the opening portion in contact with the upper frame skeleton 511 when viewed from the top is 45%, 50%, 65%, 75%, and 80%, respectively, with respect to the average opening area of all the opening portions when viewed from the top. The average opening area of the opening portion in contact with the upper frame skeleton 511 is adjusted by changing the separation distance of the lateral middle skeletons 517 from each other. At this time, the separation distance of the lateral middle skeletons 517 from each other is adjusted to be equal, respectively.

[0179] In the positive electrode current collector 5 of the liquid lead storage battery of Sample Nos. 16 to 20, the upper frame skeleton 511 constituting the lattice-shaped substrate 51 has a cross-sectional area of 2.55 mm 2 , and all the cross-sectional areas of the lateral middle skeletons 517 are 0.85 mm 2 . That is, the thickness ratio of the upper frame skeleton 511 to the lateral middle skeletons 517 is 300%. The average opening area of the opening portion in contact with the upper frame skeleton 511 when viewed from the top is 45%, 50%, 65%, 75%, and 80%, respectively, with respect to the average opening area of all the opening portions when viewed from the top. The average opening area of the opening portion in contact with the upper frame skeleton 511 is adjusted by changing the separation distance of the lateral middle skeletons 517 from each other. At this time, the separation distance of the lateral middle skeletons 517 from each other is adjusted to be equal, respectively.

[0180] In the positive electrode current collector 5 of the liquid lead storage battery of Sample Nos. 21 to 25, the upper frame skeleton 511 constituting the lattice-shaped substrate 51 has a cross-sectional area of 2.56 mm 2 , and all the cross-sectional areas of the lateral middle skeletons 517 are 0.80 mm 2 . That is, the thickness ratio of the upper frame skeleton 511 to the lateral middle skeletons 517 is 320%. The average opening area of the opening portion in contact with the upper frame skeleton 511 when viewed from the top is 45%, 50%, 65%, 75%, and 80%, respectively, with respect to the average opening area of all the opening portions when viewed from the top. The average opening area of the opening portion in contact with the upper frame skeleton 511 is adjusted by changing the separation distance of the lateral middle skeletons 517 from each other. At this time, the separation distance of the lateral middle skeletons 517 from each other is adjusted to be equal, respectively.

[0181] In the positive electrode current collector 5 of Sample Nos. 1 to 25, the constitution of the plurality of middle skeletons constituting the lattice-shaped substrate 51 isFigure 2 The positive electrode current collector 5 of the first embodiment shown is the same.

[0182] As the negative electrode current collector of Sample Nos. 1 to 25, a negative electrode current collector having the same shape and the same cross-sectional area as the positive electrode current collector 5 of Sample No. 1 was used.

[0183] Then, a paste for positive electrode mixture was prepared by mixing and kneading a lead powder mainly composed of lead monoxide with water and dilute sulfuric acid, and mixing and kneading an additive as necessary. The ratio α / (α+β) of the mass α of α-lead dioxide to the mass β of β-lead dioxide contained in the positive electrode active material after formation was 20%. Further, a paste for negative electrode mixture was prepared by mixing and kneading a lead powder mainly composed of lead monoxide with water and dilute sulfuric acid, and mixing and kneading an additive as necessary.

[0184] In addition, after the paste for positive electrode mixture was filled in the grid-shaped substrate of the positive electrode current collector, aging and drying were performed, and a positive electrode plate before formation was prepared. Similarly, after the paste for negative electrode mixture was filled in the grid-shaped substrate of the negative electrode current collector, aging and drying were performed, and a negative electrode plate before formation was prepared.

[0185] The density of the positive electrode mixture of the positive electrode plate was 4.2 g / cm 3 , and the density of the negative electrode mixture of the negative electrode plate was 4.0 g / cm 3 . The average pore diameter of the positive electrode mixture was 0.20 μm, and the porosity was 40%.

[0186] Further, as the separator, a ribbed separator composed of a porous synthetic resin and having a flat base surface and a corrugated rib projecting in a direction orthogonal to the surface direction of the base surface was prepared. The total thickness of the ribbed separator was 0.90 mm, the rib height was 0.65 mm, and the thickness of the base surface was 0.25 mm.

[0187] The positive electrode plate and the negative electrode plate before formation prepared were alternately laminated in multiple pieces with the ribbed separator interposed therebetween, and thus a plate group was prepared. The number of pieces of the positive electrode plate was 7, and the number of pieces of the negative electrode plate was 8.

[0188] The plate group was housed in an electrolytic tank, and the tabs of the positive electrode current collectors of the respective positive electrode plates were connected by a positive electrode connecting piece, and the tabs of the negative electrode current collectors of the respective negative electrode plates were connected by a negative electrode connecting piece. In addition, one end of the positive electrode connecting piece was connected to a positive electrode terminal, and one end of the negative electrode connecting piece was connected to a negative electrode terminal. Note that the electrolytic tank had a plurality of unit chambers in which the plate group was housed, but the volume of the portion below the upper horizontal line (the highest liquid surface line) of each unit chamber was 570 cm 3 . Further, the plate group was loaded with a prescribed group pressure.

[0189] ​Moreover, the opening of the cell is blocked by the cover. The positive and negative terminal posts are respectively inserted into the sleeves of the cover by insert molding, and are welded in a state in which the other ends of the positive and negative terminal posts are exposed to the outside of the liquid lead storage battery, thereby forming the positive and negative terminals. The electrolyte composed of dilute sulfuric acid having a specific gravity of 1.23 and containing aluminum sulfate at a concentration of 0.1 mol / L is injected from the liquid injection port formed in the cover up to the upper level of the cell, the liquid injection port is sealed by a plug, and the cell is subjected to formation, thereby obtaining the liquid lead storage battery.

[0190] The time from the injection of the electrolyte to the start of the power supply for the formation (i.e., the immersion time) was 30 minutes, the electric quantity for the formation was 230%, and the temperature of the electrolyte at the time of the formation was 45°C. At this time, the amount of the injected electrolyte was 375 cm 3 for each cell chamber. Note that the specific gravity of the electrolyte after the formation was 1.28.

[0191] Note that, for the subsequent disassembly investigation, a plurality of liquid lead storage batteries of each batch were prepared, and if the liquid lead storage batteries were of the same batch, they were considered to have the same structure and battery characteristics.

[0192] Each of the liquid lead storage batteries of Sample Nos. 1 to 25 thus obtained was subjected to a life test at 75°C, and the number of cycles until the life was investigated.

[0193] The conditions of the life test were as follows. First, at 75°C, a 300A discharge for 2 seconds, a CCCV charge (14.5V, maximum charge current 50A) for 60 minutes, a 25A discharge for 5 minutes, and a CCCV charge (14.5V, maximum charge current 50A) for 30 minutes were repeatedly performed in this order in a plurality of cycles, and when the voltage at the time of each discharge decreased to 7.2V, it was determined that the life was reached, and the number of cycles performed until then was set as the life.

[0194] Based on the results of the life test, comprehensive evaluation was performed based on the following criteria. If the number of cycles was 360 or more and less than 370, it was set as “O”, and if it was 370 or more, it was determined to be particularly excellent, and was set as “◎”.

[0195] Further, as reference data, at the time point at which the life test was performed for 300 cycles, the growth rate R Y of the positive grid in the up-and-down direction was confirmed. Y .

[0196] First, with respect to the positive grid before the life test, the distance Y1 from the top surface of the cover to the upper frame was measured in advance. This measurement can be performed via the liquid injection port formed in the cover, or a communication hole can be formed at an appropriate position, and the measurement can be performed via the communication hole.

[0197] Then, at the time point when the life test has passed 300 cycles, the test is temporarily stopped, and the distance Y2 from the top surface of the lid to the upper frame skeleton is measured.

[0198] Then, the difference between Yl and Y2 is found, and the growth rate R in the up-and-down direction of the positive electrode grid is calculated based on the height (the dimension in the longitudinal direction) of the grid-shaped substrate 51, 114.5 mm, and the following equation (1). Y (%).

[0199] Mathematical equation 1

[0200]

[0201] Table 9 summarizes the results above.

[0202] Table 9

[0203]

[0204] From the test results of the sample Nos. 7 to 9, 12 to 14, and 17 to 19 according to Table 9, it is known that if the sectional area of the upper frame skeleton 511 is 235% to 300% with respect to the average sectional area of the lateral middle skeletons 517, and the respective opening areas of the plurality of opening portions which are in contact with the upper frame skeleton 511 are 50% to 75% with respect to the average opening area of the entire opening portions of the grid-shaped substrate 51 when viewed in plan, there is a tendency that a liquid lead storage battery having particularly excellent life cycles can be obtained.

[0205] If the sectional area of the upper frame skeleton 511 is 235% or more with respect to the average sectional area of the lateral middle skeletons 517, there is a tendency that the growth rate R in the up-and-down direction is suppressed Y and the cycle life is improved. However, if the ratio of the sectional area with respect to the lateral middle skeletons of the upper frame skeleton is greater than 300%, it is known that even if the growth rate R in the up-and-down direction is further suppressed Y , there is no tendency that the cycle life is improved.

[0206] The disassembly investigation of each sample after the life test revealed that in No. 21 to No. 25, the lower part of the left and right frame skeletons of the positive electrode grid body was largely deformed toward the outside, and the positive electrode mixture of the peripheral opening portion was peeled off. From this, the relationship between the sectional area ratio of the upper frame skeleton and the cycle life performance can be considered as follows. First, the larger the sectional area ratio of the upper frame skeleton becomes, the larger the mechanical strength of the upper frame skeleton becomes, and therefore, the growth in the upward direction is suppressed. On the other hand, increasing the sectional area of the upper frame skeleton while keeping the weight of the positive electrode current collector constant causes the sectional area of the other middle skeletons to relatively decrease. That is, it is presumed that in the samples No. 21 to No. 25, the mechanical strength of the middle skeleton of the positive electrode current collector is small, and the deformation of the lower part of the positive electrode current collector cannot be completely prevented, which causes the peeling and peeling of the positive electrode mixture, resulting in the decrease in the capacity of the liquid lead storage battery.

[0207] Comparative test on preferred mode 2

[0208] Liquid lead storage batteries (samples No. 26 to No. 49) of a battery size of Q-85 were produced by the following method.

[0209] As shown in Table 10, in the liquid lead storage batteries of samples No. 26 to No. 49, the pore diameter (μm) and the porosity (%) of the positive electrode mixture were different, but the points other than these were the same as those of sample No. 8. When using the Figure 2 When explained, in the liquid lead storage batteries of samples No. 26 to No. 49, in the positive electrode current collector 5 thereof, the width (lateral dimension) of the grid-shaped substrate 51 was 135 mm, and the height (longitudinal dimension) was 114.5 mm. These dimensions were the intervals of the center lines of the frame skeletons from each other. The sectional area of the left frame skeleton 513, the right frame skeleton 514, and the lower frame skeleton 512 was 1.80 mm 2 .

[0210] First, the current collectors (grid-shaped substrates + tabs) for the positive electrode plate and the negative electrode plate were produced from the rolled sheet of Pb-Ca-Sn alloy by the blanking method. In the cross section obtained by cutting the current collector in the thickness direction, a rolled structure having an average interlayer distance of 20 μm was observed.

[0211] The weight of each piece of positive electrode current collector was 40.0 g. When the thickness ratio of the upper frame skeleton 511 was changed, the thickness of the middle skeleton was also changed, and the weight of the positive electrode current collector was made the same among all the samples.

[0212] In the positive current collector 5 of the liquid lead storage battery of Sample Nos. 26 to 30, the grid-shaped substrate 51 was formed in the same manner as in Sample No. 8, and the positive electrode mixture held by the grid-shaped substrate 51 had a pore diameter of 0.10 μm and a porosity of 20%, 30%, 40%, 50%, and 60%, respectively.

[0213] In the positive current collector 5 of the liquid lead storage battery of Sample Nos. 31 to 35, the grid-shaped substrate 51 was formed in the same manner as in Sample No. 8, and the positive electrode mixture held by the grid-shaped substrate 51 had a pore diameter of 0.15 μm and a porosity of 20%, 30%, 40%, 50%, and 60%, respectively.

[0214] In the positive current collector 5 of the liquid lead storage battery of Sample Nos. 36 to 39, the grid-shaped substrate 51 was formed in the same manner as in Sample No. 8, and the positive electrode mixture held by the grid-shaped substrate 51 had a pore diameter of 0.20 μm and a porosity of 20%, 30%, 50%, and 60%, respectively. In addition, in the positive current collector 5 of the liquid lead storage battery of Sample No. 8, the pore diameter was 0.20 μm and the porosity was 40%.

[0215] In the positive current collector 5 of the liquid lead storage battery of Sample Nos. 40 to 44, the grid-shaped substrate 51 was formed in the same manner as in Sample No. 8, and the positive electrode mixture held by the grid-shaped substrate 51 had a pore diameter of 0.40 μm and a porosity of 20%, 30%, 50%, and 60%, respectively.

[0216] In the positive current collector 5 of the liquid lead storage battery of Sample Nos. 45 to 49, the grid-shaped substrate 51 was formed in the same manner as in Sample No. 8, and the positive electrode mixture held by the grid-shaped substrate 51 had a pore diameter of 0.45 μm and a porosity of 20%, 30%, 50%, and 60%, respectively.

[0217] As the negative current collector of Sample Nos. 26 to 49, a negative current collector having the same shape and the same cross-sectional area as the positive current collector 5 of Sample No. 8 was used.

[0218] Then, a paste for the positive electrode mixture was prepared by mixing and kneading a lead powder mainly composed of lead monoxide with water and dilute sulfuric acid, and mixing and kneading additives as necessary. The ratio α / (α+β) of the mass α of α-lead dioxide to the mass β of β-lead dioxide contained in the positive electrode active material after formation was 20%. In addition, a paste for the negative electrode mixture was prepared by mixing and kneading a lead powder mainly composed of lead monoxide with water and dilute sulfuric acid, and mixing and kneading additives as necessary.

[0219] In addition, after filling the positive electrode paste into the grid-shaped substrate of the positive electrode current collector, maturing and drying were performed, and the positive electrode plate before formation was produced. Similarly, after filling the negative electrode paste into the grid-shaped substrate of the negative electrode current collector, maturing and drying were performed, and the negative electrode plate before formation was produced.

[0220] The density of the positive electrode paste of the positive electrode plate was 4.2 g / cm 3 The density of the negative electrode paste of the negative electrode plate was 4.0 g / cm 3 .

[0221] In addition, as the separator, a ribbed separator composed of a porous synthetic resin and having a flat base surface and a corrugated rib projecting in a direction orthogonal to the surface direction of the base surface was prepared. The total thickness of the ribbed separator was 0.90 mm, the rib height was 0.65 mm, and the thickness of the base surface was 0.25 mm.

[0222] The positive electrode plate and the negative electrode plate before formation produced by alternately laminating a plurality of pieces of the positive electrode plate and the negative electrode plate across the ribbed separator were produced, and a plate group was produced. The number of pieces of the positive electrode plate was 7, and the number of pieces of the negative electrode plate was 8.

[0223] The plate group was housed in the cell tank, the tabs of the positive electrode current collectors of the respective positive electrode plates were connected by the positive electrode connecting piece, and the tabs of the negative electrode current collectors of the respective negative electrode plates were connected by the negative electrode connecting piece. In addition, one end of the positive electrode connecting piece was connected to the positive electrode terminal, and one end of the negative electrode connecting piece was connected to the negative electrode terminal. Note that the cell tank had a plurality of unit chambers that housed the plate group, but the volume of the portion below the upper horizontal line (the highest liquid surface line) of each unit chamber was 570 cm 3 In addition, the plate group was loaded with a prescribed group pressure.

[0224] Furthermore, the opening portion of the cell tank was plugged with the lid. The positive electrode post and the negative electrode post respectively penetrated the sleeves that were insert-molded in the lid, and were welded in a state in which the other ends of the positive electrode post and the negative electrode post were exposed to the outside of the liquid lead storage battery, and the positive electrode terminal and the negative electrode terminal were formed. The electrolyte composed of dilute sulfuric acid having a specific gravity of 1.23 and containing aluminum sulfate at a concentration of 0.1 mol / L was injected from the liquid injection port formed in the lid until the upper horizontal line of the cell tank, and the liquid injection port was sealed with a plug, and the cell tank was formed, and thus the liquid lead storage battery was obtained.

[0225] The time from the injection of the electrolyte to the start of the power supply for formation (i.e., the immersion time) was 30 minutes, the amount of electricity for formation was 230%, and the temperature of the electrolyte at the time of formation was 45°C. At this time, the amount of the injected electrolyte was 375 cm 3 for each unit chamber. Note that the specific gravity of the electrolyte after formation was 1.28.

[0226] Note that, for the purpose of subsequent disassembly investigation, a plurality of batches of the liquid lead storage batteries were produced, and if the liquid lead storage batteries are of the same batch, they can be regarded as having the same structure and battery characteristics.

[0227] For each of the liquid lead storage batteries of the thus obtained Sample Nos. 26 to 49, a life test at 75°C was performed, and the number of cycles until the life was investigated.

[0228] The conditions of the life test were as follows. First, at 75°C, a 2-second 300A discharge, a 60-minute CCCV charge (14.5V, maximum charge current 50A), a 5-minute 25A discharge, and a 30-minute CCCV charge (14.5V, maximum charge current 50A) were repeatedly performed in this order in a cycle, and when the voltage at each discharge decreased to 7.2V, it was determined that the life was reached, and the number of cycles until then was set as the life.

[0229] Based on the results of the life test, evaluation was performed in accordance with the following criteria. If the number of cycles was 360 or more and less than 370, it was set as "O", and if it was 370 or more, it was judged to be particularly excellent, and set as "X".

[0230] As for the utilization rate of the active material, it was calculated by measuring the discharge capacity after the 5-hour discharge rate test was performed. In the case where the measured value of the discharge capacity was the rated capacity of the liquid lead storage battery of Q-85 size, i.e., 32 Ah or more, it was judged to be significantly excellent in the utilization rate and set as "X", and in the case where the measured value of the discharge capacity was 30 Ah or more and less than 32 Ah, it was judged to be sufficiently excellent but not significantly excellent in the utilization rate, and set as "O".

[0231] As for the comprehensive judgment, in the judgment in the life test and the 5-hour discharge rate test, it was set as "X = 2", "O = 1", respectively, and if the total points were 2 to 3 points, it was "O", and if the total points were 4 points, it was "X".

[0232] Table 10 shows the above results.

[0233] Table 10

[0234]

[0235] From the test results of Table 10, it was found that if the pore diameter of the positive electrode mixture was 0.15 μm to 0.40 μm and the porosity of the positive electrode mixture was 30% to 50%, there was a tendency that a liquid lead storage battery having particularly excellent life cycles and discharge capacity could be obtained.

[0236] Comparative Test on Preferred Mode 3

[0237] The liquid-type lead storage batteries of Q-85 size (Sample Nos. 50 to 56) were produced by the following method. In the liquid-type lead storage batteries of Sample Nos. 50 to 56, the cross-sectional area of the longitudinal middle frame having a connection point with the lower portion of the tab was different, as shown in Table 11, but the points other than this were the same as those of Sample No. 8. When the performance was evaluated using the Figure 2 In the liquid-type lead storage batteries of Sample Nos. 50 to 56, the width (lateral dimension) of the grid-shaped substrate 51 was 135 mm and the height (longitudinal dimension) was 114.5 mm in the positive current collector 5 thereof. These dimensions were the intervals of the center lines of the frame frames from each other. The cross-sectional area of each of the left frame frame 513, the right frame frame 514, and the lower frame frame 512 was 1.80 mm 2 Further, the cross-sectional area of the upper frame frame 511 constituting the grid-shaped substrate 51 was 2.23 mm 2 The cross-sectional area of each of the all lateral middle frames 517 was 0.95 mm 2 That is, the thickness ratio of the upper frame frame 511 to the lateral middle frame 517 was 235%. The average opening area when the opening portion connected to the upper frame frame 511 was observed from the top was 65% to the average opening area when all the opening portions were observed from the top.

[0238] First, the current collectors (grid-shaped substrate + tab) for the positive electrode plate and the negative electrode plate were produced from the rolled sheet of Pb-Ca-Sn alloy by the blanking method. In the cross section obtained by cutting the current collector in the thickness direction, the rolled structure having an average interlayer distance of 20 μm was observed.

[0239] The weight of each of the positive electrode current collectors was 40.0 g. When the thickness ratio of the upper frame frame 511 was changed, the thickness of the middle frame was also changed, and the weight of the positive electrode current collector was made the same among all the samples.

[0240] The range in which the starting point (connection point with the upper frame frame) of the second longitudinal middle frame 74 to 76 exists is between the position at a distance of 80 to 105 from the first reference line SI (i.e., the range located in the lower portion of the tab).

[0241] The first longitudinal middle frames 63 to 66 connect the upper frame frame 511 and the lower frame frame 512, but the first longitudinal middle frames 61, 62 do not reach the lower frame frame 512 and connect the upper frame frame 511 and the lateral middle frame 517. The second longitudinal middle frames 71 to 78 connect the upper frame frame 511 and the lower frame frame 512, but the second longitudinal middle frames 79, 80 do not reach the lower frame frame 512 and connect the upper frame frame 511 and the lateral middle frame 517. As Figure 3The lines shown, which make the first longitudinal intermediate frames 61 to 66 extend more downward than the lower frame 512, converge at a point. This convergence point Pl is located more outward than the extension line L513 of the left frame 513. Further, the lines shown, which make the second longitudinal intermediate frames 71 to 80 extend more upward than the upper frame 511, converge at a point. This convergence point P2 is located more inward than the extension line L514 of the right frame 514.

[0242] In the lead storage battery of Sample No. 50, the second longitudinal intermediate frames 74 to 76 connected to the lower portion of the tab 11 and the longitudinal intermediate frame 516 had a cross-sectional area that was 1.20 times the average cross-sectional area of all the longitudinal intermediate frames in the positive current collector 5.

[0243] In the lead storage battery of Sample No. 51, the second longitudinal intermediate frames 74 to 76 connected to the lower portion of the tab 11 and the longitudinal intermediate frame 516 had a cross-sectional area that was 1.26 times the average cross-sectional area of all the longitudinal intermediate frames in the positive current collector 5.

[0244] In the lead storage battery of Sample No. 52, the second longitudinal intermediate frames 74 to 76 connected to the lower portion of the tab 11 and the longitudinal intermediate frame 516 had a cross-sectional area that was 1.30 times the average cross-sectional area of all the longitudinal intermediate frames in the positive current collector 5.

[0245] In the lead storage battery of Sample No. 53, the second longitudinal intermediate frames 74 to 76 connected to the lower portion of the tab 11 and the longitudinal intermediate frame 516 had a cross-sectional area that was 1.35 times the average cross-sectional area of all the longitudinal intermediate frames in the positive current collector 5.

[0246] In the lead storage battery of Sample No. 54, the second longitudinal intermediate frames 74 to 76 connected to the lower portion of the tab 11 and the longitudinal intermediate frame 516 had a cross-sectional area that was 1.40 times the average cross-sectional area of all the longitudinal intermediate frames in the positive current collector 5.

[0247] In the lead storage battery of Sample No. 55, the second longitudinal intermediate frames 74 to 76 connected to the lower portion of the tab 11 and the longitudinal intermediate frame 516 had a cross-sectional area that was 1.50 times the average cross-sectional area of all the longitudinal intermediate frames in the positive current collector 5.

[0248] In the lead storage battery of Sample No. 56, the second longitudinal intermediate frames 74 to 76 connected to the lower portion of the tab 11 and the longitudinal intermediate frame 516 had a cross-sectional area that was 1.60 times the average cross-sectional area of all the longitudinal intermediate frames in the positive current collector 5.

[0249] As the negative current collector of Samples No. 50 to No. 56, a negative current collector having the same shape and the same cross-sectional area as the positive current collector 5 of Sample No. 8 was used.

[0250] Then, the lead powder mainly composed of lead monoxide was mixed with water and dilute sulfuric acid, and an additive was mixed and kneaded as necessary to produce a paste for positive electrode mixture. The ratio α / (α+β) of the mass α of α-lead dioxide to the mass β of β-lead dioxide contained in the positive electrode active material after formation was 20%. Further, the lead powder mainly composed of lead monoxide was mixed with water and dilute sulfuric acid, and an additive was mixed and kneaded as necessary to produce a paste for negative electrode mixture.

[0251] In addition, after the paste for positive electrode mixture was filled in the grid-shaped substrate of the positive electrode current collector, ripening and drying were performed to produce a positive electrode plate before formation. Similarly, after the paste for negative electrode mixture was filled in the grid-shaped substrate of the negative electrode current collector, ripening and drying were performed to produce a negative electrode plate before formation.

[0252] The density of the positive electrode mixture possessed by the positive electrode plate was 4.2 g / cm 3 The density of the negative electrode mixture possessed by the negative electrode plate was 4.0 g / cm 3 .

[0253] Further, as the separator, a ribbed separator composed of a porous synthetic resin and having a flat base surface and a corrugated rib projecting in a direction orthogonal to the surface direction of the base surface was prepared. The total thickness of the ribbed separator was 0.90 mm, the rib height was 0.65 mm, and the thickness of the base surface was 0.25 mm.

[0254] The positive electrode plate and the negative electrode plate before formation produced by alternately laminating a plurality of pieces of the positive electrode plate and the negative electrode plate across the ribbed separator were produced to produce a plate group. The number of pieces of the positive electrode plate was 7, and the number of pieces of the negative electrode plate was 8.

[0255] The plate group was housed in an electrolytic tank, and the tabs of the positive electrode current collectors of the respective positive electrode plates were connected by a positive electrode connecting piece, and the tabs of the negative electrode current collectors of the respective negative electrode plates were connected by a negative electrode connecting piece. In addition, one end of the positive electrode connecting piece was connected to a positive electrode terminal, and one end of the negative electrode connecting piece was connected to a negative electrode terminal. Note that the electrolytic tank had a plurality of unit chambers that housed the plate group, but the volume of the portion below the upper horizontal line (the highest liquid surface line) of each unit chamber was 570 cm 3 Further, the plate group was loaded with a prescribed group pressure.

[0256] Moreover, the opening of the cell is blocked by the lid. The positive and negative terminal posts are respectively inserted into the sleeves of the lid by insert molding, and are welded in a state in which the other ends of the positive and negative terminal posts are exposed to the outside of the liquid lead storage battery, thereby forming the positive and negative terminals. The electrolyte composed of dilute sulfuric acid having a specific gravity of 1.23 and containing aluminum sulfate at a concentration of 0.1 mol / L is injected from the liquid injection port formed in the lid up to the upper level of the cell, the liquid injection port is sealed by the plug, and the cell is subjected to formation, thereby obtaining the liquid lead storage battery.

[0257] The time from the injection of the electrolyte to the start of the power supply for formation (i.e., the immersion time) was 30 minutes, the amount of electricity for formation was 230%, and the temperature of the electrolyte at the time of formation was 45°C. At this time, the amount of the injected electrolyte was 375 cm 3 for each cell chamber. Note that the specific gravity of the electrolyte after formation was 1.28.

[0258] Note that, for the purpose of subsequent disassembly investigation, a plurality of liquid lead storage batteries of each batch were produced, and if the liquid lead storage batteries were of the same batch, they were considered to have the same structure and battery characteristics.

[0259] Each of the liquid lead storage batteries of Sample Nos. 50 to 56 thus obtained was subjected to a life test at 75°C, and the number of cycles until the life was investigated.

[0260] The conditions of the life test were as follows. First, at 75°C, a 300A discharge for 2 seconds, a CCCV charge (14.5V, maximum charge current 50A) for 60 minutes, a 25A discharge for 5 minutes, and a CCCV charge (14.5V, maximum charge current 50A) for 30 minutes were repeatedly performed in this order in a cycle, and when the voltage at the time of each discharge decreased to 7.2V, it was determined that the life was reached, and the number of cycles until then was set as the life.

[0261] Based on the results of the life test, the evaluation was performed in accordance with the following criteria. If the number of cycles was 360 or more and less than 370, it was set as “O”, and if it was 370 or more, it was determined to be particularly excellent, and was set as “◎”.

[0262] As for the utilization rate of the active material, it was calculated by measuring the discharge capacity after the 5-hour discharge rate test was performed. In the case where the measured value of the discharge capacity was the rated capacity of the liquid lead storage battery of Q-85 size, i.e., 32 Ah or more, it was determined that the utilization rate was significantly excellent and was set as “◎”, and in the case where the measured value of the discharge capacity was 30 Ah or more and less than 32 Ah, it was determined that the utilization rate was sufficiently excellent but could not be said to be significantly excellent, and was set as “O”.

[0263] As for the comprehensive judgment, in the judgment of the life test and the 5-hour discharge rate test, "◎=2", "O=l" are respectively set, if the total points are 2 to 3 points, it is "O", and if the total points are 4 points, it is "◎".

[0264] Table 11 summarizes the above results.

[0265] Table 11

[0266]

[0267] From the test results of Table 11, it is known that if the cross-sectional area of the longitudinal backbone connected to the lower part of the tab of the positive grid body is 1.26 times or more with respect to the average cross-sectional area of the entire longitudinal backbone, there is a tendency that a liquid lead storage battery having particularly excellent life cycle and discharge capacity can be obtained.

[0268] However, if the cross-sectional area of the longitudinal backbone connected to the lower part of the tab of the positive grid body is greater than 1.50 times, a tendency that the cycle life is reduced can be seen. Although the reason is not certain, it can be presumed that by locally making the longitudinal backbone thick, the direct current resistance of the lower part of the tab becomes small, the transfer of electrons of the positive active material is frequently performed, thereby locally promoting corrosion, and the deterioration of the positive grid body of the lower part of the tab is acceleratedly developed. In fact, in the liquid lead storage battery of Sample No. 56 after disassembly, corrosion of the longitudinal backbone, softening of the positive mixture can be significantly seen at the lower part of the tab of the positive grid body.

[0269] That is, by making the cross-sectional area of the longitudinal backbone connected to the lower part of the tab of the positive grid body 1.26 times or more and 1.50 times or less with respect to the average cross-sectional area of the entire longitudinal backbone, a liquid lead storage battery having particularly excellent life cycle and discharge capacity can be obtained.

[0270] Explanation of Reference Numerals

[0271] 1 Group of plates

[0272] 10 Positive plate

[0273] 11 Tab continuous with the grid-shaped substrate

[0274] 20 Negative plate

[0275] 30 Separator

[0276] 41 Cell

[0277] 5 Positive current collector

[0278] 51 Grid-shaped substrate

[0279] 50 Positive current collector

[0280] 510 lattice-shaped substrate

[0281] 511 upper frame skeleton

[0282] 512 lower frame skeleton

[0283] 513 left frame skeleton

[0284] 514 right frame skeleton

[0285] 516 longitudinal middle skeleton

[0286] 517 transverse middle skeleton

[0287] 61-66 first longitudinal middle skeleton

[0288] 71-85 second longitudinal middle skeleton

[0289] 91 reinforcing skeleton

[0290] 92-94 reinforcing skeleton

Claims

1. A liquid lead-acid battery comprising a positive electrode plate having a positive current collector and a positive flux, wherein in the liquid lead-acid battery, The positive current collector has a rectangular grid-shaped substrate and a tab continuous with the grid-shaped substrate. The positive electrode agent is retained on the grid-shaped substrate. The grid-shaped substrate has a frame skeleton forming the four sides of the rectangle, and multiple middle skeletons connected to the frame skeleton and located further inward than the frame skeleton. The frame skeleton has an upper frame skeleton located on the upper side of the grid-shaped substrate and extending laterally, a lower frame skeleton located on the lower side of the grid-shaped substrate and extending laterally, and a pair of longitudinal frame skeletons extending in the longitudinal direction. The tab protrudes upward from a position offset from the center of the long side of the upper frame towards one side of either of the pair of longitudinal frames. The plurality of central frame members include a plurality of longitudinal central frame members extending from the upper frame member toward the lower frame member or from the lower frame member toward the upper frame member, and a plurality of transverse central frame members extending from one side of the pair of longitudinal frame members toward the other side or from the other side of the pair of longitudinal frame members toward one side. At least a portion of the plurality of longitudinal central skeletons, existing in the range between the center between the pair of longitudinal skeletons and the first longitudinal skeleton of the longitudinal skeleton on the side where the tabs are absent, extend obliquely from the lower frame skeleton side toward the upper frame skeleton side and directly reach the first longitudinal central skeleton of the upper frame skeleton. The longitudinal central frame, extending obliquely from one side of the lower frame towards the other side of the upper frame, all directly reaches the upper frame. On one side of the first vertical frame, the angle between the first vertical middle frame and the upper frame is less than 90°. The connection points between the first vertical frame skeleton and the upper frame skeleton exist only within the specified range. The cross-sectional area of ​​the upper frame skeleton is 235% to 300% of the average cross-sectional area of ​​the horizontal frame skeleton, and the opening area of ​​each of the multiple openings connected to the upper frame skeleton when viewed from above is 50% to 75% of the average opening area of ​​all openings of the grid-like substrate. The lines extending from the first vertical frame towards the lower frame converge to a single point, and the lines extending from the second vertical frame towards the upper frame converge to a single point.

2. The liquid lead-acid battery according to claim 1, wherein, The connection point between the first vertical frame and the upper frame exists only within the range of 2 / 5 of the distance between the first vertical frame and the pair of vertical frames.

3. The liquid lead-acid battery according to claim 1 or 2, wherein, At least a portion of the multiple longitudinal central skeletons existing between the center of the pair of longitudinal frame skeletons and the second longitudinal frame skeleton, which is the longitudinal frame skeleton on the side where the pole lugs are located, are second longitudinal central skeletons that extend obliquely from the upper frame skeleton toward the lower frame skeleton.

4. The liquid lead-acid battery according to claim 2, wherein, At least a portion of the plurality of longitudinal central skeletons existing in the range between the center between the pair of longitudinal frame skeletons and the second longitudinal frame skeleton, which is the side of the longitudinal frame skeleton where the pole lugs are located, are second longitudinal central skeletons that extend obliquely from the upper frame skeleton toward the lower frame skeleton. The connection point between the second longitudinal frame and the upper frame exists only within the range of 3 / 5 of the distance between the second longitudinal frame and the pair of longitudinal frames.

5. The liquid lead-acid battery according to claim 1 or 2, wherein, In the rectangle forming the frame, the horizontal sides are longer than the vertical sides.

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