JP6337496B2 - Lead acid battery - Google Patents

Description

  The present invention relates to a technique for suppressing cracks in a lid member.

  For example, a lead storage battery used for automobiles and the like includes a synthetic resin battery case and a synthetic resin lid member that seals the battery case. And the terminal part is formed with respect to the cover member. The terminal portion is constituted by a cylindrical bushing made of lead alloy integrated with the lid member by insert molding, and a pole column inserted into the bushing.

  It is known that the bushing and the pole column are corroded and expanded by the electrolytic solution in the battery case. Since the expansion of the bushing and the pole column causes cracking of the lid member, in Patent Document 1 below, the expansion of the bushing is absorbed by the expansion absorber provided between the cylindrical portion formed on the lid member and the bushing. By doing so, the crack of the lid member is suppressed.

Utility Model Registration No. 3005437

However, in the above structure, it is necessary to provide the expansion absorbing member exclusively, and there is a problem that the number of parts increases.
This invention is completed based on the above situations, Comprising: It aims at suppressing the crack of a cover member, without adding a new component.

  The lead storage battery disclosed by this specification has a power generation element, a battery case that houses the power generation element, a base part that seals the battery case, and a mounting part that extends from the base part toward the inside of the battery case. A lid member, a cylindrical bushing provided in the mounting portion, and a pole column connected to the power generation element and inserted into the bushing cylinder, wherein the mounting portion is the battery case of the bushing An inner corner formed by the lower end surface and the inner peripheral surface of the bushing, the outer corner portion of the bushing having a covering portion that covers the outer corner portion formed by the lower end surface and the outer peripheral surface facing inward; Unlike the part, it has a chamfered shape.

  The “chamfered shape” means that the target corner portion is made into a “shape with no corners” as a curved surface or a slope.

  According to the present invention, it is possible to suppress cracking of the lid member without adding new parts.

The perspective view of the lead acid battery which concerns on Embodiment 1 of this invention. AA line sectional view in FIG. Bushing perspective view The figure which expanded the B section of FIG. The figure which shows the comparative example which made the lower surface outside corner part non-chamfered shape in order to explain the crack of a mounting part (equivalent to B part of Drawing 2) The figure which shows the comparative example which made the lower surface outside corner part non-chamfered shape in order to explain the crack of a mounting part (equivalent to B part of Drawing 2) Cross section of bushing The figure which expanded the C section in FIG. Sectional drawing of the metal mold | die which shape | molds a cover member (The molding part of a mounting part is shown) Sectional drawing of the bushing which concerns on Embodiment 2 of this invention The figure which expanded the C section of FIG. Sectional drawing of the bushing which concerns on Embodiment 3 of this invention (a lower surface outer corner part is shown) Sectional drawing of the bushing which concerns on other embodiment (a lower surface outer corner part is shown) Cross-sectional view of a bushing according to another embodiment

(Outline of this embodiment)
First, an outline of the lead storage battery of the present embodiment will be described. The lead storage battery includes a power generation element, a battery case that houses the power generation element, a base member that seals the battery case, and a lid member that has a mounting part that extends from the base part toward the inside of the battery case. A cylindrical bushing provided in a portion, and a pole column connected to the power generation element and inserted into the bushing tube, wherein the mounting portion is a lower end surface facing the inside of the battery case of the bushing The outer corner portion of the bushing is chamfered unlike the inner corner portion formed by the lower end surface and the inner peripheral surface of the bushing. It is.

  In this configuration, the outer corner portion of the bushing is chamfered, so that the stress applied to the covering portion covering the outer corner portion is dispersed and the stress is locally concentrated due to the expansion caused by the corrosion of the outer corner portion. Can be suppressed. And it can suppress that a mounting part cracks and a crack reaches the outer surface of a mounting part. As a result, if the crack reaches the outer surface of the mounting portion, it is possible to prevent the electrolyte from entering from the crack and to prevent the gap between the bushing and the mounting portion from being easily expanded. Thus, it is possible to delay the expansion of the electrolyte due to corrosion of the bushing by delaying the creeping of the electrolyte. Furthermore, since the inner corner portion is not chamfered, the entry point of the electrolyte into the gap between the bushing and the pole column can be narrowed to make it difficult for the electrolyte to enter. Therefore, it becomes possible to slow the expansion accompanying the corrosion of the bushing and the pole column, and the crack of the lid member can be suppressed. Moreover, in this configuration, since the cracking of the lid member is suppressed by changing the shape of the bushing, there are no newly added parts, and the number of parts does not increase.

  In the lead storage battery, the outer corner portion of the bushing has a curved surface connecting the lower end surface and the outer peripheral surface. Thereby, the stress concerning the coating | coated part which covers an outer side corner part can be disperse | distributed more uniformly, and it can suppress further that a stress concentrates locally.

  In the lead storage battery, the bushing protrudes from the outer peripheral surface, has an annular shape, and has a plurality of protrusions arranged at intervals in the extending direction of the cylinder, and the mounting of the corner portion of the protrusion is performed. The length of the creeping distance facing the portion is longer than the length of the creeping distance facing the mounting portion of the outer corner portion. Thereby, the creeping distance along the outer peripheral surface of the bushing is lengthened, and the cracking of the lid member is suppressed while suppressing the electrolyte from seeping out from the gap between the mounting portion and the bushing to the surface side of the lid member. be able to.

  In the lead storage battery, the lowermost protrusion of the plurality of protrusions is disposed on the lower end surface. According to this, it is possible to increase the distance to the portion that tends to be the starting point of the crack of the covering portion, and it is possible to further delay the expansion accompanying the corrosion of the bushing.

  In this lead storage battery, the lower end surface of the bushing is a flat surface. If a flat surface is provided, it is difficult for the resin to enter the shaft hole side of the bushing when the lid member is integrally formed by pouring the resin into the mold in which the bushing is inserted. Therefore, it can suppress that a burr | flash generate | occur | produces at the front-end | tip of a coating | coated part.

  In the present specification, the “chamfered shape” means that a target corner portion is a “shape having no corners” as a curved surface or a slope. On the other hand, the “non-chamfered shape” means that the target corner portion is “an angular shape having a corner or a shape substantially equal to the angular shape”. The shape substantially equal to the square shape is, for example, a case where the length or radius of one side of the slope is sufficiently small, such as “0.1 mm or less”, even when the corner portion is sloped or arcuate and the corner is eliminated. .

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS.
1. Lead Acid Battery Structure The lead acid battery 10 includes a battery case 20, an electrode plate group 30 that is a power generation element, a lid member 50, and terminal portions 60N and 60P as shown in FIGS. In the following description, the width direction of the battery case 20 (the arrangement direction of the terminal portions 60N and 60P) is the X direction, the height direction is the Y direction, and the depth direction of the battery case 20 is the Z direction.

  The battery case 20 is made of a synthetic resin and has a box shape having four outer walls 21 and a bottom wall 22 and an open top surface. The inside of the battery case 20 is partitioned into a plurality of cell chambers 23 by partition walls (not shown). Each cell chamber 23 is provided side by side in the width direction (X direction in FIG. 1) of the battery case 20, and the electrode plate group 30 is accommodated in each cell chamber 23 together with the electrolyte U made of dilute sulfuric acid. .

  The electrode plate group 30 includes a positive electrode plate 30P, a negative electrode plate 30N, and a separator 30C that partitions both the electrode plates 30P and 30N. Each of the electrode plates 30P and 30N is configured by filling a lattice with an active material, and ears 31P and 31N are provided at the upper part. The ears 31 </ b> P and 31 </ b> N are provided to connect the electrode plates 30 </ b> P and 30 </ b> N having the same polarity through the strap 32 in each cell chamber 23.

  The lid member 50 is made of synthetic resin, and as shown in FIG. 1, a base portion 51 that seals the upper surface of the battery case 20, a pair of mounting portions 55 that are integrally formed on both sides of the base portion 51 in the X direction, And an outer peripheral wall 53 formed along the outer peripheral edge. The outer peripheral wall 53 extends downward from the outer peripheral edge of the base portion 51, and has a structure that surrounds the upper end portion of the outer wall 21 constituting the battery case 20. After assembling the lid member 50 to the battery case 20, the entire periphery is welded to the battery case 20 by heat welding or the like.

  As shown in FIG. 1, a positive terminal portion 60P and a negative terminal portion 60N are provided on both sides of the lid member 50 in the X direction.

  As shown in FIG. 2, the negative terminal portion 60N includes a bushing 70N and a pole 90N. The bushing 70N is made of a metal such as a lead alloy, and has a hollow cylindrical shape having an axial hole through which the pole column 90N passes in the center. As shown in FIGS. 3 and 7, the bushing 70 </ b> N includes a terminal connection portion 73 and a main body portion 75. The terminal connection portion 73 and the main body portion 75 are formed vertically, and a flange portion 74 is formed at the boundary between both the portions 73 and 75. On the outer peripheral surface 76 of the main body 75, annular projections 77A to 77D having an annular shape are formed. The annular protrusions 77A to 77D are provided at a plurality of stages (four stages in this example) at equal intervals in the axial direction (Y direction) of the bushing 70N. The annular protrusions 77A to 77D are formed on the entire circumference of the bushing 70N in the circumferential direction. Of the annular protrusions 77 </ b> A to 77 </ b> D, the annular protrusion 77 </ b> D positioned at the lowermost position is disposed on the lower end surface 78 of the bushing 70, and the lower surface of the annular protrusion 77 </ b> D is connected to the lower end surface 78 as shown in FIGS. Match. Moreover, the collar part 74 protrudes outward from the outer peripheral surface 76 of the bushing 70N, and has an annular shape.

  As shown in FIG. 2, the bushing 70 </ b> N penetrates the base 51 of the lid member 50 in the Y direction, and the terminal connection portion 73 protrudes from the upper surface of the base of the lid member 50 and is exposed. An external connection terminal (not shown) such as a harness terminal is assembled to the terminal connection portion 73. The main body 75 is located inside the mounting portion 55 formed on the base 51 of the lid member 50.

  As shown in FIG. 2, the mounting portion 55 extends from the back surface of the base portion 51 to the inside of the battery case, that is, downward. The mounting portion 55 has a cylindrical shape and penetrates the base portion 51 of the lid member 50 vertically. Since the lid member 50 is manufactured by pouring resin into a die having the bushing 70N inserted therein and integrally molding the resin, the resin covers the outer peripheral surface of the bushing 70N and is buried between the annular protrusions 77 of each step without any gap. Therefore, the inner peripheral surface of the mounting portion 55 is unevenly fitted with the annular protrusion 77.

  A covering portion 57 is formed at the lower end of the mounting portion 55 over the entire circumference. As shown in FIG. 4, the covering portion 57 covers the lower end surface 78 while covering the outer surface of the lower outer corner portion 83 of the annular protrusion 77 </ b> D positioned at the lowermost position. The front end 57 </ b> A of the covering portion 57 reaches the hole edge of the inner peripheral surface (shaft hole) 71. The covering portion 57 suppresses the electrolyte U from entering the gap between the mounting portion 55 and the annular protrusion 77.

  The pole column 90N is made of a metal such as a lead alloy and has a generally cylindrical shape. The pole 90N is located in the cylinder of the bushing 70N. Of the pole 90N, the upper end 91 is joined to the terminal connection 73 of the bushing 70N by welding, and the base end 93 is joined to the strap 32N of the electrode plate group 30. The outer peripheral surface of the pole column 90N and the inner peripheral surface 71 of the bushing 70N are tapered toward the upper side to improve the insertion property of the polar column with respect to the inner peripheral surface 71 of the bushing 70. .

  Similarly to the negative terminal portion 60N, the positive terminal portion 60P includes a bushing 70P and a pole 90P. Since the basic structure of the positive terminal portion 60P is the same as that of the negative terminal portion 60N, description thereof is omitted.

2. Measures against cracking of the lid member 50 Since there is a gap between the bushing 70 (generic name for 70P and 70N) and the pole 90 (generic name for 90P and 90N), the electrolyte U in the battery case 20 crawls the gap. It rises and adheres to the inner surface of the bushing 70 and the outer surface of the pole column 90. Further, the electrolytic solution also enters between the lower end surface 78 of the bushing 70 and the covering portion 57 formed on the mounting portion 55, and the electrolytic solution adheres to the lower end surface 78 of the bushing 70.

  The bushing 70 and the pole 90 are known to expand due to corrosion by the electrolytic solution U. As shown in FIG. 5, if the lower outer corner portion 83 of the lowermost annular projection 77D has a non-chamfered shape, The expanded bushing 170 pushes the mounting portion 155 outward and downward. That is, as indicated by an arrow F shown in FIG. 5, a force is applied obliquely downward from the inside. Therefore, when the limit is exceeded, a crack K1 enters the attachment portion 155 obliquely from the lower end portion of the bushing 170. 5 and 6 are diagrams showing a comparative example in which the lower outer corner portion 83 of the lowermost annular projection 77D has a non-chamfered shape in order to explain cracks in the mounting portion 155. FIG.

  Since the crack K1 that has entered the mounting portion 155 advances outward due to the expansion of the bushing 170, when the tip of the crack K1 reaches the outer surface of the mounting portion 155, the electrolyte U enters from there. Then, the electrolyte U easily enters the gap between the bushing 170 and the mounting portion 155. As a result, as shown in FIG. 6, the electrolyte U easily rises through the gap between the mounting portion 155 and the annular projection 77. Therefore, corrosion of the bushing 170 proceeds and the bushing 170 expands even at a position close to the base 51. As the bushing 170 expands, an excessive force is applied to the terminal portion 60 (a general term for 60P and 60N), and as a result, the lid member 50 is cracked.

  Therefore, in the lead storage battery 10, as shown in the cross-sectional views of FIGS. 7 and 8, the lower inner corner portion 81 formed by the lower end surface 78 and the inner peripheral surface 71 of the bushing 70 does not chamfer. “Non-chamfered shape”. By setting the lower surface inner corner portion 81 to the “non-chamfered shape”, it is possible to narrow the entry point of the electrolyte solution U into the gap between the bushing 70 and the pole column 90 and make it difficult for the electrolyte solution U to enter. Therefore, it becomes possible to slow the expansion accompanying the corrosion of the bushing 70 and the pole 90, and the crack of the lid member 50 can be suppressed. Further, the vibration of the pole 90 due to vibration can be suppressed, and cracks, breakage, etc. at the welded portion between the bushing 70 and the pole 90 can be prevented.

  On the other hand, unlike the lower surface inner corner portion 81, the lower surface outer corner portion 83 formed by the outer peripheral surface 79 and the lower end surface 78 of the annular projection 77D positioned at the lowermost portion of the bushing 70 has a “chamfered shape”. . Specifically, the lower outer corner portion 83 has a curved surface shape with an arc surface, and both surfaces 78 and 79 are connected by an arc surface having a radius of “2 mm”.

  If the lower surface outer corner portion 83 has a “chamfered shape”, it is possible to disperse stress applied to the covering portion 57 due to expansion of the lower surface outer corner portion 83 due to corrosion. It is possible to suppress the stress from being concentrated on the corners of the corners). And since it can control that crack K1 enters into attachment part 55, attachment part 55 is cracked temporarily, a crack reaches the outer surface of attachment part 55, and a crack occurs in a peripheral part of terminal part 60. Can be suppressed.

  In addition, since the lower outer corner portion 83 is a curved surface (specifically, a circular arc surface), the stress applied to the covering portion 57 covering the lower outer corner portion 83 can be more evenly distributed. Therefore, the concentration of stress can be further suppressed.

  In addition, the lowermost annular projection 77D is disposed on the lower end surface 78 of the bushing 70N. Therefore, the distance from the tip 57A of the covering portion 57 to the portion where the covering portion 57 is likely to start cracking is longer than when the lower end surface 78 has no annular protrusion 77. Therefore, it is possible to delay the electrolyte U entering from the front end 57A of the covering portion 57 from reaching the lower outer corner portion 83 corresponding to the starting point of cracking, and to delay the expansion of the lower outer corner portion 83 due to corrosion. It becomes possible. Therefore, it is possible to further suppress the crack K1 from entering the mounting portion 155.

  Further, by making the lower surface outer corner portion 83 “chamfered”, as shown in FIG. 4, the distance L1 from the lower surface outer corner portion 83 to the outer surface of the mounting portion 55 is larger than the distance L2 in FIG. It becomes longer and the thickness of the portion of the mounting portion 55 where the crack K1 enters increases. Therefore, the covering portion 57 is difficult to break.

  Further, in the bushing 70N, other corner portions excluding the lower surface outer corner portion 83 of the annular projection 77D positioned at the lowermost position, for example, the upper surface outer corner portion 84 of the annular projection 77D, and the upper surface corner portion 85 of the terminal connection portion 73. In addition, the corner portion 87 of the flange portion 74 and the corner portion 89 of the annular protrusions 77A to 77C have a non-chamfered shape that is not chamfered.

  The bushing 70 includes a positive bushing 70P and a negative bushing 70N. In the lead storage battery 1, the lower inner corner portion 81 has a “non-chamfered shape” in both the bushings 70 </ b> P and 70 </ b> N. On the other hand, the lower outer corner portion 83 has a “chamfered shape” only for the negative electrode bushing 70N, and the positive electrode bushing 70P has a “non-chamfered shape”.

  The lower end surface 78 of the bushing 70 is a flat surface. Specifically, a plane from point (a) to point (b) shown in FIG. 8 corresponding to the edge of the inner peripheral surface (shaft hole) 71 is a flat surface.

  By doing in this way, it can suppress that a burr | flash generate | occur | produces in the front-end | tip part 57A of the coating | coated part 57. FIG. More specifically, FIG. 9 shows a part of a mold for molding the lid member 50. The mold 100 includes a mold 110 having a molding surface 111 for molding the mounting portion 55, and a molding. At this time, a core pin 120 inserted into the inner peripheral surface (shaft hole) 71 of the bushing 70 is provided.

  If the lower end surface 78 of the bushing 70 is a flat surface, when the lid 100 is injection molded by filling the mold 100 with resin, the resin filled in the mold 100 passes through the path indicated by the broken line arrow shown in FIG. It becomes difficult to go around the gap between the peripheral surface (shaft hole) 71 and the core pin 120. Therefore, it is possible to suppress the occurrence of burrs at the tip portion 57 </ b> A of the covering portion 57.

2. Description of Effect According to the lead storage battery 10, since the crack of the lid member 50 is suppressed by changing the shape of the lower outer corner portion 83, there is no newly added component and the number of components is not increased.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIGS.
In the first embodiment, the lower inner corner portion 81 of the bushing 70N on the negative electrode side has a “non-chamfered shape”, and the lower outer corner portion 83 has a “chamfered shape by an arc surface”. In the second embodiment, as shown in FIGS. 10 and 11, the lower surface inner corner portion 81 of the bushing 270N on the negative electrode side has a “non-chamfered shape”, and the lower surface outer corner portion 83 has a “chamfered shape by an inclined surface”. . Specifically, the lower outer corner portion 83 has a slope shape of 45 ° with a side length Lc of “2 mm”.

  Even when the lower surface outer corner portion 83 has a “chamfered shape by an inclined surface”, the stress applied to the covering portion 57 that covers the lower surface outer corner portion 83 due to the expansion caused by the corrosion of the lower surface outer corner portion 83 is the same as in the first embodiment. It is possible to suppress the concentration of stress locally by dispersing. Since the crack K1 can be prevented from entering the mounting portion 55, the mounting portion 55 is broken down and the crack reaches the outer surface of the mounting portion 55, or a crack occurs in the peripheral portion of the terminal portion 60. This can be suppressed.

<Embodiment 3>
Next, Embodiment 3 of the present invention will be described with reference to FIG.
In the first embodiment, an example in which the lower outer corner portion 83 of the lowermost annular projection 77D is chamfered with an arc surface having a radius of “2 mm” is shown. In the third embodiment, the lower outer corner portion 83 of the lowermost annular projection 77D is chamfered with an arc surface having a radius of “1 mm”.

  As in the third embodiment, even when the lower outer corner portion 83 is chamfered with an arc surface having a radius of “1 mm”, the lower outer corner portion 83 is expanded due to the corrosion of the lower outer corner portion 83 as in the first embodiment. It is possible to disperse the stress applied to the covering portion 57 that covers the surface to suppress local concentration of the stress. The chamfering depth (arc radius) is preferably at least R = 0.5 mm.

  Further, the creepage distance of the corner portion facing the mounting portion 55 becomes shorter as the chamfer becomes deeper and becomes longer if the chamfer becomes deeper.

  The bushing 370N of the third embodiment is provided with annular projections 77A to 77D on the outer peripheral surface 76 as in the first embodiment, and the other annular projections 77A to 77C except the annular projection 77D positioned at the lowermost portion are corners. The part 89 is not chamfered. Therefore, when the creeping distance of the corner portion facing the mounting portion 55 is compared between the annular protrusions 77A to 77C and the annular protrusion 77D, the annular protrusions 77A to 77C that are not chamfered have a longer creepage distance. Become.

  For example, the creeping distance of the lower outer corner portion 83 of the annular protrusion 77D is “Lce” in FIG. On the other hand, if the size of the corner portion is the same (Lcd = Lfg, Lde = Lgh), the creepage distance of the corner portion 89 on the lower surface side of the annular protrusion 77C is “Lfg” + “Lgh” in FIG. Therefore, the corner portion 89 of the annular protrusion 77C has a longer creepage distance.

  By increasing the creepage distance, the effect of suppressing the electrolyte U from seeping out to the surface side of the lid member 50 from the gap between the mounting portion 55 and the bushing 370N is enhanced, and thus cracking of the lid member 50 is suppressed. be able to.

  Note that “Lcd” is the length from point (c) to point (d) in FIG. 12, “Lde” is the length from point (d) to point (e) in FIG. 12, and “Lce” is This is the length from point (c) to point (e) in FIG. “Lfg” is the length from point (f) to point (g) in FIG. 12, and “Lgh” is the length from point (g) to point (h) in FIG.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  (1) In the first embodiment, the lower surface outer corner portion 83 of the positive electrode bushing 70P has a “non-chamfered shape”, but the positive electrode bushing 70P is also formed on the lower surface outer corner portion in the same manner as the negative electrode bushing 70N. 83 may be a “chamfered shape”. That is, in both of the bushings 70P and 70N, the lower surface inner corner portion 81 may have a “non-chamfered shape”, and the lower surface outer corner portion 83 may have a “chamfered shape”. The “chamfered shape” may be a shape without corners, and may be either the chamfered shape by the curved surface (arc surface) shown in the first embodiment or the chamfered shape by the inclined surface shown in the second embodiment.

  (2) In the first embodiment, the upper surface outer corner portion 84 of the annular protrusion 77D is shown as “non-chamfered shape”, but the lower surface outer corner portion 83 only needs to be chamfered. Like the bushing 470N shown, in addition to the lower surface outer corner portion 83, the upper surface outer corner portion 84 of the annular protrusion 77D may be further chamfered.

  (3) In the first embodiment, the example in which the plurality of annular protrusions 77A to 77D are formed on the outer peripheral surface of the bushing 70N has been described. However, the annular protrusions 77A to 77D are abolished like the bushing 570N illustrated in FIG. Also good. In the bushing 570N shown in FIG. 14, the lower inner corner portion 81 formed by the inner peripheral surface 71 and the lower end surface 78 of the bushing has a “non-chamfered shape”, and the outer peripheral surface 76 and the lower end surface 78 of the bushing 70 are The lower surface outer corner portion 83 formed has a “chamfered shape”. For this reason, as in the first embodiment, the stress applied to the covering portion 57 covering the lower surface outer corner portion 83 due to the expansion caused by the corrosion of the lower surface outer corner portion 83 is dispersed to suppress local concentration of stress. Can do.

  (4) In Embodiment 1, the example which made the lower surface outside corner part 83 into the curved-surface shape was shown. Specifically, an example of an arc surface has been shown, but an ellipse surface or the like may be used.

DESCRIPTION OF SYMBOLS 10 ... Lead storage battery 20 ... Battery case 30 ... Electrode plate group (an example of "power generation element" of the present invention)
50 ... Lid member 51 ... Base 55 ... Mounting part 57 ... Covering part 60P, 60N ... Terminal part 70P, 70N ... Bushing 81 ... Bottom inner corner part (of the present invention Example of “inner corner”)
83 ... lower outer corner portion (an example of "outer corner portion" of the present invention)
77 ... annular protrusion (an example of the "protrusion" of the present invention)
78 ... Lower end face 80 ... Polar pole

Claims (4)

Power generation elements,
A battery case containing the power generation element;
A lid member having a base for sealing the battery case and a mounting part extending from the base toward the battery case;
A cylindrical bushing provided in the mounting portion;
A pole pole connected to the power generation element and inserted into the bushing cylinder;
The mounting portion has a covering portion that covers an outer corner portion formed by a lower end surface facing the inside of the battery case and an outer peripheral surface of the bushing,
The outer corner portion of the bushing is chamfered, unlike the inner corner portion formed by the lower end surface and the inner peripheral surface of the bushing ,
The outer corner portion of the bushing has a curved surface connecting the lower end surface and the outer peripheral surface,
The lead-acid battery , wherein the curved surface is an arc surface having a radius of 0.5 mm or more . The lead acid battery according to claim 1 ,
The bushing protrudes from the outer peripheral surface, is formed in an annular shape, and has a plurality of protrusions arranged at intervals in the extending direction of the cylinder,
The length of the creeping distance of the corner portion of the protrusion facing the mounting portion is longer than the length of the creeping distance of the outer corner portion facing the mounting portion. The lead acid battery according to claim 2 ,
The lowermost protrusion among the plurality of protrusions is a lead-acid battery disposed on the lower end surface. The lead-acid battery according to any one of claims 1 to 3 ,
The lower end surface of the bushing is a lead storage battery that is a flat surface.

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