Lead-acid storage batteries

Abstract

This invention provides a lead-acid storage battery with a medium or greater capacity. However, it allows only a very small current to flow into lead-acid storage batteries, which have a structure that enables this. Prevents the fracture of the positive electrode strip from stretching of the positive electrode plate which occurs in... For effective long-term operation, this invention is a lead-acid battery. It consists of a group of electrode plates in which the positive and negative electrode plates are connected. Laminates are alternately layered over protruding segmented plates to connect the strip couplers of polarized electrode plates. Similarly, in the group of electrode plates and electrode holders, which connect the strips and electrode terminals, there are... A characteristic feature is the distance from the two edges of the joint between the electrode placement areas on the top side. The positive electrode and the positive electrode bar reach the end of the positive electrode bar in the longitudinal direction, which Appearing on the same side as each edge section, the width of the positive electrode strip is 0 to 20 millimeters. 10 to 25 millimeters, and the thickness of the positive electrode strip is 5 to 15 millimeters, and in addition... The height of the positive electrode plate, excluding the protruding part and the lower base, is 180 millimeters. more than

Description

lead acid battery

[0001] The present invention relates to a lead-acid battery, and more specifically to the dimensions of a positive electrode strap and the joining position between the positive electrode strap and a positive electrode post seat (hereinafter sometimes referred to as a "positive electrode post seat") that connects the positive electrode strap to a positive electrode post in a lead-acid battery that has a medium or larger capacity but passes only a relatively small current.

[0002] A widely known lead-acid battery includes a plate assembly formed by alternately stacking a plurality of positive plates, each formed by filling a substrate primarily composed of lead or a lead alloy with a positive active material paste, and a plurality of negative plates, each formed by filling a substrate primarily composed of lead or a lead alloy with a negative active material paste, with glass fiber separators interposed between them, and the plate assembly is housed in a battery case. The plate lugs of plates of the same polarity in the plate assembly are connected by straps, and poles are attached to the pole seats connected to the straps. In recent years, there has been an increasing demand for longer life for such lead-acid batteries, and some industrial lead-acid batteries are required to have a life of 15 years or more, e.g., 20 years.

[0003] To extend the life of lead-acid batteries, for example, a lead-acid battery has been proposed, which has a plate group in which the lugs of a plurality of plates are connected by straps made of lead or lead alloy, and in which the cross-sectional area of ​​the strap parallel to the plate surface direction of each lug gradually decreases with increasing distance from the electrode posts (Patent Document 1). This invention relates to a large-capacity, high-current lead-acid battery, and proposes a strap shape that prevents strap melting due to temperature rise during high-current discharge and minimizes waste of lead or lead alloy. Also proposed is a valve-regulated lead-acid battery made of a specified material, characterized in that, when the length of the connection between the positive pole and the positive strap is M1 (mm) and the length of the positive strap is M2 (mm), M1 / M2 ≥ 0.4. This invention provides a valve-regulated lead-acid battery with improved corrosion resistance and excellent life performance by changing the shape of the connection between the positive pole and the positive strap in order to prevent the progression of corrosion from gaps, such as cracks, that exist at the connection between the positive pole and the positive strap.

[0004] JP 2000-173579 A JP 2003-323881 A

[0005] The present invention provides a lead-acid battery having a structure that can effectively prevent breakage of the positive electrode strap caused by elongation of the positive electrode plate that occurs during long-term operation, in a lead-acid battery that has a medium or larger capacity but passes only a relatively small current.

[0006] The invention described in the above Patent Document 1 relates to a lead-acid battery with a large capacity and a large current, and provides a structure to prevent the strap from melting due to heat generated when a large current flows. For example, in the embodiment, in a 2V-1,000Ah lead-acid battery, １０ The strap temperature is measured when the battery is discharged at a large current of 3,000 A, and the strap is evaluated by observing whether it has melted or not. １０In a lead-acid battery that only passes a small current of less than 1 A, the discharge current does not cause a temperature rise that would cause the strap to melt.

[0007] However, even with lead-acid batteries that only carry such small currents, reports have been emerging of straps breaking and breaking after a long period of use, such as 15 to 20 years. The inventors investigated the cause of this and discovered that with long periods of use, corrosion occurs in the positive plate due to floating charge or charge / discharge cycles, causing the positive plate itself to stretch and the positive strap to bend upward from below. This causes stress to concentrate, particularly at the edge of the joint between the positive post seat and the positive strap, causing cracks and accelerating corrosion in the cracked area. In particular, the inventors discovered that the risk of positive strap breakage is extremely high when the positive plate is tall, for example, when the height of the positive plate excluding the lug and foot is 180 mm or more, or even 200 mm or more.

[0008] To prevent the breakage of the positive strap, the positive strap could be made stronger. However, this would significantly increase manufacturing costs due to the increased amount of materials used and the overall weight of the lead-acid battery. Furthermore, even if the positive strap is made slightly stronger, the force of corrosion-induced elongation of the electrode plate is too strong to prevent the strap from bending and the resulting breakage. Therefore, the inventors conducted extensive research to determine how to prevent the breakage of the positive strap without increasing costs. As a result, they found that the above-mentioned problem can be effectively solved by setting the distances (a-1, a-1') from the two edges of the joint between the positive post seat and the positive strap to the longitudinal ends of the positive strap on the same side of each edge, the width (b-1) of the positive strap, and the thickness (c-1) of the positive strap to the specified dimensions below. Furthermore, they also found that the length (e-1) of the joint between the positive post seat and the positive post can be significantly shortened.

[0009] That is, the present invention provides: (1) a lead-acid battery comprising: an electrode plate group in which positive and negative electrode plates are alternately stacked with separators interposed therebetween; straps connecting lugs of electrode plates of the electrode plate group having the same polarity; and electrode post seats connecting the straps to electrode posts, wherein the distances (a-1, a-1') from two edge portions of a joint between the electrode post seat on the positive electrode side and the positive strap to longitudinal ends of the positive straps on the same side of each edge portion are 0 to 20 mm; the width (b-1) of the positive strap is 10 to 25 mm; and the thickness (c-1) of the positive strap is 5 to 15 mm; and the height (d-1) of the positive electrode plate, excluding the lugs and feet, is 180 mm or greater.

[0010] As preferred embodiments, (2) the lead-acid battery according to (1) above, in which the length (e-1) of the joint between the seat of the positive electrode post on the positive electrode side and the positive electrode post is 60% or less of the circumferential length of the cross section of the positive electrode post in a cross section perpendicular to the longitudinal direction of the positive electrode post; (3) the lead-acid battery according to (1) above, in which the length (e-1) of the joint between the seat of the positive electrode post on the positive electrode side and the positive electrode post is 30 to 60% of the circumferential length of the cross section of the positive electrode post in a cross section perpendicular to the longitudinal direction of the positive electrode post; (4) the lead-acid battery according to any one of (1) to (3) above, in which the distances (a-1, a-1') from two edge portions of the joint between the seat of the positive electrode post on the positive electrode side and the positive electrode strap to the longitudinal ends of the positive electrode strap on the same side of each edge portion are 10 to 20 mm; (5) The lead-acid battery according to any one of (1) to (4) above, wherein the width (b-1) of the positive electrode strap is 10 to 20 mm; (6) The lead-acid battery according to any one of (1) to (5) above, wherein the thickness (c-1) of the positive electrode strap is 5 to 10 mm; (7) The lead-acid battery according to any one of (1) to (6) above, wherein the height (d-1) of the positive electrode plate excluding the lug and foot portions is 200 mm or more; (8) The lead-acid battery according to any one of (1) to (7) above, wherein the rated capacity is 100 Ah to 2,000 Ah; (9) The lead-acid battery according to any one of (1) to (7) above, wherein the rated capacity is 100 Ah to 1,000 Ah; (10) The lead-acid battery according to any one of (1) to (7) above, wherein the rated capacity is 500 Ah to 1,000 Ah; (11) The maximum current during operation is 0.6C. １０ (12) The lead-acid battery according to any one of (1) to (10), wherein the maximum current during operation is 0.1 to 0.3 C. １０ (13) The lead-acid battery according to any one of (1) to (12) above, in which the length (total length) of the positive electrode strap is 250 to 300 mm; (14) The lead-acid battery according to any one of (1) to (12) above, in which the length (total length) of the positive electrode strap is 260 to 290 mm.

[0011] The lead-acid battery of the present invention can effectively prevent breakage of the positive electrode strap due to elongation caused by corrosion of the positive electrode plate, which occurs during long-term operation of a lead-acid battery that has a medium or larger capacity but passes only a relatively small current, and can also reduce manufacturing costs.

[0012] Fig. 1 is an external view showing one embodiment of the lead acid battery of the present invention; Fig. 2 is a front view showing one embodiment of an electrode plate group housed in the lead acid battery of the present invention; Fig. 3 is a plan view of the lead acid battery of the present invention with the lid removed; Fig. 4 is a schematic view showing a positive electrode strap, a seat for a positive electrode post, and a positive electrode post of the lead acid battery of the present invention; Fig. 5 is a schematic view showing the height (d) of the electrode plate;

[0013] The lead-acid battery of the present invention includes a plate assembly in which positive plates (e.g., positive plates formed by filling a substrate primarily made of lead or a lead alloy with a positive active material paste) and negative plates (e.g., negative plates formed by filling a substrate primarily made of lead or a lead alloy with a negative active material paste) are alternately stacked with separators (e.g., a retainer mat primarily made of glass fiber) interposed therebetween; a strap connecting the lugs of plates of the plate assembly with the same polarity; and a pole seat connecting the strap to a pole. Here, the strap and the pole seat are preferably primarily made of lead or a lead alloy. The lead-acid battery can be manufactured by a conventional method.

[0014] The lead-acid battery of the present invention will be described below with reference to the drawings. FIG. 1 is an external view showing one embodiment of a lead-acid battery (A) of the present invention, with the upper view being a plan view and the lower view being a front view. FIG. 2 is a front view showing one embodiment of an electrode plate group (10) housed in the lead-acid battery of the present invention shown in FIG. 1. The left view shows the positive electrode side (10-1), and the right view shows the negative electrode side (10-2). FIG. 3 is a plan view of the lead-acid battery (A) of the present invention shown in FIG. 1 with the lid (2) removed. The lead-acid battery (A) includes a hollow, approximately rectangular parallelepiped battery case (1) having an opening on its top surface, and a lid (2) joined to the peripheral edge (1-1) of the opening of the battery case (1) by thermal fusion or the like. Here, the battery case (1) and the lid (2) are formed of a synthetic resin, such as polypropylene or ABS resin. The lid (2) has terminal insertion holes through which the poles (4), i.e., the positive pole (4-1) and the negative pole (4-2), are inserted. Lead alloy bushings are inserted into these terminal insertion holes and molded into the synthetic resin material of the lid (2). The positive pole (4-1) and the negative pole (4-2) are integrally welded to the bushings, and their tips protrude above the lid (2) to form the positive and negative terminals, respectively. Epoxy resin is injected onto the bushings and the welded portions between the bushings and the poles, and then hardened to form the terminal sealing portion (5). An electrolyte solution consisting of dilute sulfuric acid of a predetermined concentration is injected into the battery case (1) through a filling port provided on the top surface of the lid (2). A rubber valve is placed over the filling port, and a vent plug (3) is attached over the rubber valve to seal the lead-acid battery (A).

[0015] The battery case (1) contains an electrode plate group (10) as shown in FIG. 2 . The electrode plate group (10) includes a plurality of positive electrode plates (11-1) and a plurality of negative electrode plates (11-2). The positive electrode plates (11-1) and negative electrode plates (11-2) are alternately stacked with separators (not shown), such as mat-like separators mainly made of fine glass fibers, interposed therebetween. The positive electrode plate (11-1) includes a positive electrode lug (12-1) protruding upward, which are integrally connected by a positive electrode strap (16-1) extending in the stacking direction of the electrode plate group (10-1). Similarly, the negative electrode plate (11-2) includes a negative electrode lug (12-2) protruding upward, which are integrally connected by a negative electrode strap (16-2) extending in the stacking direction of the electrode plate group (10-2). As shown in FIG. 3, the positive electrode strap (16-1) and the negative electrode strap (16-2) are both connected to the positive electrode pole (4-1) serving as the positive terminal and the negative electrode pole (4-2) serving as the negative terminal, respectively, via the pole seat (15) [positive electrode side (15-1) and negative electrode side (15-2)].

[0016] As shown in Figure 3, the electrode plate current collecting part (13) is composed of a pole seat (15) and a strap (16). Here, the strap (16) is formed in a substantially rectangular shape in plan facing the stacking direction of the electrode plate group (10). The pole seat (15) is formed in a substantially triangular shape in plan. The pole seat (15) is formed integrally with the pole (4) whose main components are brass and lead or a lead alloy. The electrode plate current collecting part (13) is integrally formed by welding the pole seat (15), which is integrally provided on the pole (4), to the strap (16).

[0017] 4 is a schematic diagram showing only the positive electrode strap (16-1), the positive electrode post seat (15-1), and the positive electrode post (4-1) of the lead-acid battery (A) of the present invention, with the upper diagram being a plan view and the lower diagram being a front view. In the present invention, the distances (a-1, a-1') from two edge portions (20-1a, 20-1a') of the joint between the positive electrode post seat (15-1) and the positive electrode strap (16-1) to the longitudinal ends (16-1a, 16-1a') of the positive electrode strap (16-1) on the same side of each edge portion (20-1a, 20-1a') are 0 to 20 mm, preferably 10 to 20 mm. Here, the distances (a-1, a-1') may be the same or different. The width (b-1) of the positive electrode strap (16-1) is 10 to 25 mm, preferably 10 to 20 mm. The thickness (c-1) of the positive electrode strap (16-1) is 5 to 15 mm, preferably 5 to 10 mm. By setting the distance (a-1, a-1') from the edge portion (20-1a, 20-1a') to the positive electrode strap end portion (16-1a, 16-1a'), the width (b-1) of the positive electrode strap (16-1), and the thickness (c-1) of the positive electrode strap (16-1) within the above ranges, breakage of the positive electrode strap (16-1) due to elongation caused by corrosion of the positive electrode plate (11-1) can be effectively prevented over a long period of time. Furthermore, even if the width (b-1) and thickness (c-1) of the positive electrode strap (16-1) exceed the above upper limits, no significant improvement in breakage prevention effect is observed, and the use of unnecessary materials not only leads to increased costs but also increases the mass of the battery itself. Furthermore, in the lead-acid battery of the present invention, the height (d) of the electrode plate (11), particularly the height (d-1) of the positive electrode plate (11-1), must be 180 mm or more, preferably 200 mm or more, with a maximum of approximately 500 mm. Below the above lower limit, the positive electrode plate itself undergoes small elongation due to corrosion, and the positive electrode strap (16-1) is not subjected to stress sufficient to break it. Here, the height (d) of the electrode plate (11) refers to the height of the electrode plate excluding the lug portion (12) and foot portion (17), as shown in FIG. 5 .Additionally, in the lead-acid battery (A) of the present invention, the length (e-1) of the joint between the positive electrode post seat (15-1) and the positive electrode post (4-1) is preferably 60% or less of the circumferential length of the cross section of the positive electrode post (4-1) in a cross section perpendicular to the longitudinal direction of the positive electrode post (4-1), and more preferably 30 to 60% of the circumferential length of the cross section of the positive electrode post (4-1). Here, the positive electrode post seat (15-1) is typically a flat plate having a substantially uniform thickness, preferably 5 to 15 mm, more preferably 8 to 10 mm. The length (total length) of the positive electrode strap (16-1) is not particularly limited, but is preferably 250 to 300 mm, more preferably 260 to 290 mm. Here, the strap (16) is mainly composed of lead or a lead alloy, and is relatively soft with low hardness. Therefore, the distances (a-1, a-1') are almost independent of the length of the positive electrode strap (16-1), and the effects of the present invention can be achieved as long as they are within the above range. On the other hand, since the negative electrode plate (11-2) does not elongate due to corrosion on the negative electrode side, the distances (a-2, a-2') from two edge portions (20-2a, 20-2a') of the joint portion between the negative electrode side pole seat (hereinafter sometimes referred to as the "negative electrode pole seat") (15-2) and the negative electrode strap (16-2) to the longitudinal end portions (16-2a, 16-2a') of the negative electrode strap (16-2) present on the same side of the respective edge portions (20-2a, 20-2a'), the width (b-2) and thickness (c-2) of the negative electrode strap (16-2), and the length (e-2) of the joint portion between the negative electrode pole seat (15-2) and the negative electrode pole (4-2) are all arbitrary. However, if the above dimensions are made too small, problems such as localized heat generation and melting of the negative electrode plate current collector (13-2) may occur during operation of the lead-acid battery, even if only a small current flows. Therefore, it is usually sufficient to set the width (b-2) and thickness (c-2) of the negative electrode strap (16-2) to 10 mm or more and 5 mm or more, respectively, and to set the length (e-2) of the joint portion between the negative electrode post seat (15-2) and the negative electrode post (4-2) to 30% or more of the perimeter of the cross section of the negative electrode post in a cross section perpendicular to the longitudinal direction of the negative electrode post, and to set the thickness of the negative electrode post seat (15-2) to 5 mm or more.The dimensions of the negative electrode plate (11-2) are approximately the same as those of the positive electrode plate. For example, the height (d-2) of the negative electrode plate (11-2) is usually the same as the height (d-1) of the positive electrode plate.

[0018] The present invention is applied to lead-acid batteries having a medium or larger capacity but which pass only a relatively small current, and the maximum current during operation is preferably 0.6 C. １０ Ampere (A) or less, more preferably 0.1 to 0.3C １０ This applies to lead-acid batteries with a capacity of 0.6C. １０ Repeated charging and discharging at a current exceeding 100 amperes (A) significantly affects the battery's internal temperature. This temperature increase accelerates corrosion, significantly elongating the electrode plates, potentially causing premature strap breakage and shortening the battery's lifespan. Here, a lead-acid battery with a medium or higher capacity typically refers to a lead-acid battery with a rated capacity of approximately 100 Ah to 2,000 Ah, preferably approximately 100 Ah to 1,000 Ah, and more preferably approximately 500 Ah to 1,000 Ah.

[0019] The present invention will be described in more detail in the following examples, but the present invention is not limited to these examples.

[0020] (Manufacturing of Lead Acid Battery) The lead acid batteries used in Examples 1 to 8 and 11 to 15 and Comparative Examples 1 to 18 were manufactured as follows: 22 unformed positive electrode plates (11-1) and 23 unformed negative electrode plates (11-2) manufactured by a known method were alternately stacked and combined with a mat-like separator mainly made of fine glass fiber sandwiched between them, and then the lugs (12-1, 12-2) of the electrode plates of the same polarity were welded to the electrode post seats (15-1, 15-2) previously joined to the electrode posts while melting the lead to form straps (16-1, 16-2). At this time, for the positive electrode side, the distances (a-1, a-1') from the two edge portions (20-1a, 20-1a') of the joint between the electrode post seat (15-1) and the strap (16-1) to the longitudinal ends (16-1a, 16-1a') of the strap (16-1) on the same side of each edge portion, the width (b-1) of the strap, the thickness (c-1) of the strap, as well as the length (L-1) of the strap and the length (e-1) of the joint between the electrode post seat (15-1) and the electrode post (4-1) were adjusted to the predetermined dimensions shown in Table 1. On the negative electrode side, the distances (a-2, a-2') from the two edge portions (20-2a, 20-2a') of the joint between the electrode post seat (15-2) and the strap (16-2) to the longitudinal ends (16-2a, 16-2a') of the strap (16-2) on the same side of each edge portion were 30 mm, the strap width (b-2) was 20 mm, the strap thickness (c-2) was 10 mm, and the strap length (L-2) was the positive electrode strap length (L-1) plus 10 mm. Furthermore, the length (e-2) of the joint between the electrode post seat (15-2) and the electrode post (4-2) was 55% of the perimeter of the cross section of the electrode post (4-2) perpendicular to the longitudinal direction of the electrode post (4-2). Here, the electrode post seats (15-1, 15-2) were all flat plates, and their thicknesses were all 10 mm. When the pole seat (15-1, 15-2) and the lead add-on were welded together while melting the lead add-on to form the straps (16-1, 16-2), in the case of a battery in which the strap was thicker than the pole seat, the strap was shielded with a jig to prevent the melted lead add-on from flowing into the upper part of the pole seat. The cross-sectional shape perpendicular to the longitudinal direction of the positive pole (4-1) and the negative pole (4-2) was both approximately circular, and their diameters were both 40 mm.The heights (d-1, d-2) of the plates (both positive and negative) were 400 mm. The plate assembly (10) thus integrated was inserted into a polypropylene battery case (1), and the lid (2) was heat-sealed to produce an unformed lead-acid battery. An electrolyte solution with a specific gravity of 1.23 was then poured into the battery case so that the volume was 100% of the theoretical space volume of the plate assembly. Next, the battery case was formed by applying electricity for 72 hours with an amount of electricity approximately 10 times the rated capacity. After the formation of the battery case, the electrolyte was replenished, and then a supplementary charge was performed to produce a 2V-1,000Ah lead-acid battery. In Examples 9 and 10 and Comparative Examples 19 to 22, 2V-450Ah lead-acid batteries were produced using the same procedure as above, except that the heights (d-1, d-2) of the plates (both positive and negative) were 180 mm. In Reference Example 1, a 2V-375Ah lead-acid battery was manufactured using the same procedure as above, except that the heights (d-1, d-2) of the plates (both positive and negative plates) were 150 mm. In Examples 11 and 13, the strap length (L-1) was 300 mm compared to Examples 1 and 5, respectively. In Examples 12 and 14, the strap length (L-1) was 250 mm compared to Examples 1 and 5, respectively. In the former, the separator thickness was increased to increase the spacing between the plates, thereby lengthening the strap length. In the latter, the separator thickness was reduced to decrease the spacing between the plates, thereby shortening the strap length. Inserting electrode plate assemblies with positive electrode straps of different lengths into battery cases of the same size can result in problems such as extra space being created between the electrode plate assembly and the battery case, or the inability to insert the electrode plate assembly. Therefore, in this Example, this Comparative Example, and Reference Example 1, battery cases of optimal dimensions for inserting electrode plate assemblies with positive electrode straps of the maximum length of 300 mm were used, and for electrode plate assemblies with strap lengths of less than 300 mm, spacers of different thicknesses were inserted on both sides of the electrode plate assembly as appropriate to prevent excess space from being generated. Here, in each of the above Examples, Comparative Examples, and Reference Example 1, the amount of lead in the grid of the positive electrode plate, excluding the lugs and feet, per battery capacity was almost the same.

[0021] (High-Temperature Accelerated Float Charge Test and Capacity Test) In the examples and comparative examples, a high-temperature accelerated float charge test and a capacity test were performed as follows. The lead-acid batteries manufactured as described above were placed in a thermostatic chamber at 60°C and subjected to a high-temperature accelerated float charge test at a float charge voltage of 2.23 V / cell. After the start of the float charge test, one year (32 days at 60°C) was passed in terms of years converted to 25°C, and the lead-acid batteries were removed from the thermostatic chamber at 60°C and a capacity test was performed in an environment at 25°C. Here, the capacity test conditions were a discharge current of 0.1 C. １０ The discharge end voltage was 1.8 V / cell. This operation was repeated, and the point at which the lead-acid battery fell below 80% of its rated capacity was defined as the end of its life. In this test, all batteries that fell below 80% of their rated capacity in a period of less than 20 years converted to 25°C were due to strap rupture. When the battery reached 20 years converted to 25°C, the high-temperature accelerated float charge test and capacity test were terminated, and a disassembly investigation was conducted to check for rupture of the positive electrode strap (16-1).

[0022] (Examples 1 to 15, Comparative Examples 1 to 22, and Reference Example 1) The high-temperature accelerated floating charge test and capacity test were carried out on each of the lead-acid batteries manufactured as described above to check whether or not the positive electrode strap (16-1) had broken. The results are shown in Table 1.

[0023]

[0024] In Examples 1 to 4, the distances (a-1, a-1') from the two edge portions (20-1a, 20-1a') of the joint between the positive electrode post seat (15-1) and the positive electrode strap (16-1) to the longitudinal ends (16-1a, 16-1a') of the positive electrode strap on the same side of each edge portion were set to 0 mm. That is, the width of the positive electrode post seat (15-1) was maximized. Here, in Example 1, the width (b-1) and thickness (c-1) of the positive electrode strap were both minimized within the range of the present invention. No breakage of the positive electrode strap (16-1) occurred. In Examples 2 to 4, the width (b-1) and thickness (c-1) of the positive electrode strap were changed within the range of the present invention compared to Example 1. In all cases, no breakage of the positive electrode strap (16-1) was observed, and the results were cost-effective.

[0025] On the other hand, in Comparative Examples 1 to 8, the distances (a-1, a-1') were set to 0 mm, similar to Examples 1 to 4. In Comparative Examples 1 and 2, the width (b-1) of the positive electrode strap was set to less than the range of the present invention, compared to Example 2. Breakage occurred in all of the positive electrode straps (16-1). Thus, even if the width of the positive electrode post seat (15-1) and the thickness (c-1) of the positive electrode strap were maximized within the range of the present invention, breaking occurred in the positive electrode strap (16-1) when the width (b-1) of the positive electrode strap was set to less than the range of the present invention, i.e., less than 10 mm. In Comparative Examples 3 and 4, the thickness (c-1) of the positive electrode strap was set to less than and more than the range of the present invention, respectively, compared to Examples 1 and 2. In Comparative Example 3, where the thickness (c-1) of the positive electrode strap was set to less than the range of the present invention, i.e., 4 mm, breaking occurred in the positive electrode strap (16-1). On the other hand, in Comparative Example 4, in which the thickness (c-1) of the positive electrode strap was set to exceed the range of the present invention, no breakage occurred in the positive electrode strap (16-1), but the thickness (c-1) was excessive and not cost-effective. In Comparative Examples 5 and 6, the thickness (c-1) of the positive electrode strap was set to be less than the range of the present invention and greater than the range of the present invention, respectively, compared to Examples 3 and 4. In Comparative Example 5, the width of the positive electrode post seat (15-1) and the thickness (b-1) of the positive electrode strap were maximized within the range of the present invention, but it was found that when the thickness (c-1) of the positive electrode strap was less than the range of the present invention, i.e., 4 mm, breakage occurred in the positive electrode strap (16-1). Furthermore, in Comparative Example 6, no breakage occurred in the positive electrode strap (16-1), but similarly to the above, it was not cost-effective. In Comparative Examples 7 and 8, the width (b-1) of the positive electrode strap exceeded the range of the present invention, and the thickness (c-1) of the positive electrode strap was less than the range of the present invention and exceeded the range of the present invention, respectively. As is clear from Comparative Example 7, even when the width of the positive electrode post seat (15-1) was maximized and the width (b-1) of the positive electrode strap was excessively increased to exceed the range of the present invention, when the thickness of the positive electrode strap was less than the range of the present invention, i.e., 4 mm, fracture occurred in the positive electrode strap (16-1).In Comparative Example 8, the positive electrode strap (16-1) did not break, but it was not at all cost-effective.

[0026] Examples 5 to 8 had the same width (b-1) and thickness (c-1) of the positive electrode strap as Examples 1 to 4, respectively, except that the distance (a-1, a-1') was 20 mm. That is, the width of the positive electrode post seat (15-1) was minimized within the scope of the present invention. In all cases, no breakage of the positive electrode strap (16-1) was observed, and the cost was even more reasonable. Furthermore, compared to Examples 1 to 4, the cost was better.

[0027] On the other hand, in Comparative Examples 9 to 16, the distances (a-1, a-1') were set to 20 mm, similar to Examples 5 to 8. In Comparative Examples 9 and 10, the width (b-1) of the positive electrode strap was set to less than the range of the present invention compared to Example 6. Breakage occurred in all of the positive electrode straps (16-1). In Comparative Examples 11 and 12, the thickness (c-1) of the positive electrode strap was set to less than the range of the present invention and greater than the range of the present invention compared to Examples 5 and 6, respectively. In Comparative Example 11, in which the thickness (c-1) of the positive electrode strap was set to less than the range of the present invention, i.e., 4 mm, breakage occurred in the positive electrode strap (16-1). On the other hand, in Comparative Example 12, in which the thickness (c-1) of the positive electrode strap was set to greater than the range of the present invention, breakage did not occur in the positive electrode strap (16-1), but it could not be said to be cost-effective. In Comparative Examples 13 and 14, the thickness (c-1) of the positive electrode strap was set to be less than the range of the present invention and greater than the range of the present invention, respectively, compared to Examples 7 and 8. In Comparative Example 13, fracture occurred in the positive electrode strap (16-1). On the other hand, in Comparative Example 14, fracture of the positive electrode strap (16-1) did not occur, but the cost was not justified. In Comparative Examples 15 and 16, the width (b-1) of the positive electrode strap was set to be greater than the range of the present invention, and the thickness (c-1) of the positive electrode strap was set to be less than the range of the present invention and greater than the range of the present invention, respectively. As can be seen from Comparative Example 15, even when the width (b-1) of the positive electrode strap was set to be greater than the range of the present invention, fracture occurred in the positive electrode strap (16-1) when the thickness (c-1) of the positive electrode strap was less than the range of the present invention. In Comparative Example 16, fracture of the positive electrode strap (16-1) did not occur, but the cost was not justified at all. Furthermore, in Comparative Examples 17 and 18, the distance (a-1, a-1') exceeded the range of the present invention. As is clear from Comparative Example 17, when the distance (a-1, a-1') exceeded the range of the present invention even slightly, the positive electrode strap (16-1) broke. Furthermore, even when the width (b-1) and thickness (c-1) of the positive electrode strap were significantly increased beyond the range of the present invention, as in Comparative Example 18, when the distance (a-1, a-1') exceeded the range of the present invention, the strap (16-1) broke.

[0028] Example 9 is the same as Example 1, except that the distance (a-1, a-1') was 0 mm, the width (b-1) of the positive electrode strap was 10 mm, and the thickness (c-1) of the positive electrode strap was 5 mm, but the height (d-1) of the positive electrode plate was 180 mm. Example 10 is the same as Example 5, except that the distance (a-1, a-1') was 20 mm, the width (b-1) of the positive electrode strap was 10 mm, and the thickness (c-1) of the positive electrode strap was 5 mm, but the height (d-1) of the positive electrode plate was 180 mm. In both cases, no breakage of the positive electrode strap (16-1) occurred. Meanwhile, Comparative Examples 19 and 20, like Example 9, were the same as Example 9, except that the distance (a-1, a-1') was 0 mm, but the height (d-1) of the positive electrode plate was 180 mm, and the width (b-1) and thickness (c-1) of the positive electrode strap were outside the range of the present invention. In addition, in Comparative Examples 21 and 22, similar to Example 10, the distance (a-1, a-1') was 20 mm, the height (d-1) of the positive electrode plate was 180 mm, and the width (b-1) and thickness (c-1) of the positive electrode strap were outside the range of the present invention. In all of Comparative Examples 19 to 22, breakage was observed in the positive electrode strap (16-1). From the above, it was found that even when the height (d-1) of the positive electrode plate (d-1) was 180 mm, breakage of the positive electrode strap (16-1) could be prevented by setting the distance (a-1, a-1'), the width (b-1) and the thickness (c-1) of the positive electrode strap within the range of the present invention, as in the case when the height (d-1) of the positive electrode plate (d-1) was 400 mm. Note that in Reference Example 1, the presence or absence of breakage of the positive electrode strap (16-1) was investigated under the same conditions as Comparative Examples 1 and 20, except that the height (d-1) of the positive electrode plate was 150 mm. In Comparative Examples 1 and 20, i.e., when the height (d-1) of the positive electrode plate was 400 mm and 180 mm, respectively, breakage of the positive electrode strap (16-1) was observed, but in Reference Example 1, in which the height (d-1) of the positive electrode plate was 150 mm, breakage of the positive electrode strap (16-1) was not observed. This is thought to be because the height (d-1) of the positive electrode plate was small, so that the elongation due to corrosion of the electrode plate itself was small, and therefore, no stress that would cause breakage of the positive electrode strap (16-1) was generated in the first place.Furthermore, the thickness (c-1) of the positive electrode strap is 18 mm in all of Comparative Examples 4, 6, 8, 12, 14, 16, and 18. In this way, when the thickness (c-1) of the positive electrode strap exceeds 15 mm, the difference with the thickness of the seat of the positive electrode post becomes too large, and therefore, when forming the positive electrode strap (16-1), the repetitive work of melting the lead and pouring the melted lead increases, which leads to an increase in costs and is undesirable.

[0029] In all of Examples 11 to 14, the length (L-1) of the positive electrode strap was changed. In all cases, no breakage of the positive electrode strap (16-1) was observed. In Example 15, the length (e-1) of the joint between the positive electrode pole seat (15-1) and the positive electrode pole (4-1) was 30% of the perimeter of the cross section of the positive electrode pole (4-1) perpendicular to the longitudinal direction of the positive electrode pole (4-1). Similarly, no breakage of the positive electrode strap (16-1) was observed.

[0030] The lead-acid battery of the present invention is a lead-acid battery that has a medium or larger capacity but passes only a relatively small current, and is not only capable of effectively preventing strap breakage over a long period of time, but also has relatively low manufacturing costs, etc., and is therefore expected to be widely used in the future as an industrial lead-acid battery that requires a long life.

[0031] A Lead-acid battery 1 Battery case 1-1 Periphery of opening of battery case 2 Lid 3 Exhaust plug 4 Electrode pole 4-1 Positive electrode pole 4-2 Negative electrode pole 5 Terminal sealing part 10 Electrode plate group 10-1 Positive electrode plate group 10-2 Negative electrode plate group 11 Electrode plate 11-1 Positive electrode plate 11-2 Negative electrode plate 12 Ear part 12-1 Positive electrode ear part 12-2 Negative electrode ear part 13 Electrode plate current collector part 13-1 Positive electrode plate current collector part 13-2 Negative electrode plate current collector part 15 Electrode pole seat 15-1 Positive electrode side electrode pole seat 15-2 Negative electrode side electrode pole seat 16 Strap 16-1 Positive electrode strap 16-2 Negative electrode strap 17 Feet 16a, 16a' Both ends of the strap in the longitudinal direction 16a-1, 16a-1' Both ends of the positive electrode strap in the longitudinal direction 16a-2, 16a-2' Both ends of the negative electrode strap in the longitudinal direction 20a, 20a' Two edge portions of the joint between the electrode post seat and the strap 20-1a, 20-1a' Two edge portions of the joint between the positive electrode post seat and the positive electrode strap 20-2a, 20-2a' Two edge portions of the joint between the negative electrode post seat and the negative electrode strap a, a' Distance from the two edge portions of the joint between the electrode post seat and the strap to the end of the strap in the longitudinal direction that is on the same side of each edge portion a-1, a-1' Distance from the two edge portions of the joint between the positive electrode post seat and the positive electrode strap to the end of the positive electrode strap in the longitudinal direction that is on the same side of each edge portion a-2, a-2' Distance from the two edges of the joint between the negative electrode post seat and the negative electrode strap to the longitudinal end of the negative electrode strap on the same side of each edge b Width of strap b-1 Width of positive electrode strap b-2 Width of negative electrode strap c Thickness of strap c-1 Thickness of positive electrode strap c-2 Thickness of negative electrode strap d Height of electrode plate d-1 Height of positive electrode plate d-2 Height of negative electrode plate e Length of joint between electrode post seat and electrode post e-1 Length of joint between positive electrode post seat and positive electrode post e-2 Length of joint between negative electrode post seat and negative electrode post L Length of strap L-1 Length of positive electrode strap L-2 Length of negative electrode strap

Claims

1. A lead-acid storage battery consists of a group of electrode plates in which the positive and negative electrode plates are alternately laminated by protruding segments that connect pairs of electrode plates with the same polarity as in the group of electrode plates and electrode shoulders that connect the electrode strips and electrodes, which are characterized by the distance (a-1,a-1') from the two edges of the connection between the electrode shoulder on the positive electrode side and the positive electrode strip to the end of the positive electrode strip in the length direction which appears on the same side as each segment.

2. Lead-acid storage batteries under claim 1, where the length (e-1) of the interconnected section between the positive electrode strip and the positive electrode section is 30 to 60% of the perimeter length of the positive electrode section perpendicular to the longitudinal direction of the positive electrode section.Lead-acid storage batteries under claim 1 or 2 where the rated capacity is 100Ah to 2000Ah, and the maximum operating current is 0.6C10 Amperes (A) or less;