Lead-acid batteries, and vent caps for lead-acid batteries.

Abstract

This lead acid battery 1 comprises: a battery case 10; electrode plates 30A, 30B that are housed in the battery case 10; an electrolyte solution U that is housed in the battery case 10; and a liquid plug 70 that is attached to the battery case 10. The liquid plug 70 comprises: a cylindrical plug main body 71; a splash prevention body 90 that is positioned inside the plug main body; and a plurality of catalyst devices 100A, 100B for promoting a reaction for generating water from a gas that is generated by a charge / discharge reaction. The plurality of catalyst devices 100A, 100B each comprise: a cylindrical case 110 which is open in a surface; a catalyst layer 120 which is housed in the case 110; and a permeable membrane 130 which covers the surface of the catalyst layer and is permeable to a gas. The plurality of catalyst devices 100A, 100B are arranged to be vertical or inclined with respect to the plug main body 71 so that the surface on which the permeable membrane 130 is provided has an angle with respect to the horizontal direction. The plurality of catalyst devices 100A, 100B are arranged at the same height as a whole, or arranged at least partially at the same height.

Description

Lead acid battery, lead acid battery liquid plug

[0001] The present invention relates to a liquid plug for use in a lead-acid battery.

[0002] In lead-acid batteries, the electrolyte (water) is electrolyzed during the charging reaction, generating oxygen and hydrogen gases, so the battery is designed with a vent hole in the top of the liquid plug or in the lid to vent these gases.One way to deal with the loss of electrolyte due to electrolysis is to equip the lead-acid battery with a catalyst component that promotes the recombination reaction of oxygen and hydrogen gases (the reaction that turns them back into water).

[0003] In relation to the above technology, paragraph 18 of the following Patent Document 1 describes, "A catalyst component for a lead-acid battery, the catalyst component having a catalyst layer containing a catalyst that promotes a reaction that generates water or water vapor from oxygen and hydrogen, and a configuration in which at least a portion of the water or water vapor generated by the catalytic reaction condenses and circulates back into the lead-acid battery, the catalyst component having gas permeability as a whole." Also, paragraph 46 describes, "More preferably, the baffle plate may be inclined toward the inside of the lead-acid battery. The inclined baffle plate promotes the droplets to slide down toward the inside of the lead-acid battery, further suppressing the loss of electrolyte."

[0004] Furthermore, paragraph 16 of the following Patent Document 2 states, "A container that is one aspect of the present invention is a container that houses a catalytic material in a lead-acid battery, the catalytic material including a catalyst that promotes a reaction that produces water or water vapor from oxygen and hydrogen, and the container has an opening that is covered with a membrane, the membrane communicates the oxygen, hydrogen, and water vapor between the catalytic material and the outside of the container, and is oriented at an angle of 0° to 80° with respect to the direction of gravity."

[0005] Patent No. 6576297 Utility Model Registration No. 3229214

[0006] When a lead-acid battery is charged, oxygen gas and hydrogen gas are generated, causing the electrolyte level to rise. If a catalyst device (catalyst component) is placed inside the electrolyte plug in addition to a splash guard, the overall length of the electrolyte plug will increase, and the distance from the liquid level to the electrolyte plug will become shorter when the liquid level rises.

[0007] In particular, if the catalytic device is positioned vertically or at an angle to the plug body, the water recombined from the gas can easily return to the battery container, but the overall length of the liquid plug increases, which can cause the rising liquid level to reach the liquid plug.If the liquid level reaches the liquid plug, the electrolyte may flow inside the liquid plug and leak out of the exhaust hole.

[0008] An object of the present invention is to prevent leakage of the electrolyte by ensuring a sufficient distance from the liquid surface of the electrolyte to the liquid plug while maintaining the catalytic performance of the catalytic device.

[0009] The lead-acid battery includes a battery case, electrode plates housed in the battery case, an electrolyte housed in the battery case, and an electrolyte plug attached to the battery case.

[0010] The liquid plug includes a cylindrical plug body, a splash guard located inside the plug body, and a plurality of catalytic devices that promote a reaction that produces water from gas generated by a charge / discharge reaction.

[0011] The catalytic devices each have a cylindrical case with an open surface, a catalytic layer housed in the case, and a permeable membrane covering the surface of the catalytic layer and allowing gas to pass through. The catalytic devices are arranged vertically or at an angle relative to the plug body so that the surface of the permeable membrane is at an angle to the horizontal. The catalytic devices are arranged either entirely at the same height in the vertical direction, or at least partially at the same height.

[0012] This technology can also be used in liquid plugs for lead-acid batteries.

[0013] This technology can suppress leakage of electrolyte by ensuring the distance from the electrolyte surface to the liquid plug while maintaining the catalytic performance of the catalytic device.

[0014] Perspective view of a lead-acid battery Perspective view of a battery case Cross-section of a lead-acid battery (cross-section of line A-A in Figure 1) Front view of the liquid stopper Enlarged view of a part of Figure 3 (liquid stopper portion) Perspective view of a catalytic device with a part cut out Perspective view of a catalytic device with a part cut out Figure showing the vertical positional relationship between two catalytic devices Figure showing the vertical positional relationship between two catalytic devices Horizontal cross-section of the liquid stopper Vertical cross-section of the liquid stopper Horizontal cross-section of the liquid stopper Figure showing the catalytic device positioned at an angle Figure showing the arrangement of the catalytic device Figure showing the arrangement of the catalytic device Front view of the liquid stopper

[0015] (Outline of this embodiment) (1) A lead-acid battery according to one embodiment of the present invention includes a battery case, electrode plates housed in the battery case, an electrolyte housed in the battery case, and an electrolyte plug attached to the battery case.

[0016] The liquid plug includes a cylindrical plug body, a splash guard located inside the plug body, and a plurality of catalytic devices that promote a reaction that produces water from gas generated by a charge / discharge reaction.

[0017] The catalytic devices each have a cylindrical case with an open surface, a catalytic layer housed in the case, and a permeable membrane covering the surface of the catalytic layer and allowing gas to pass through. The catalytic devices are arranged vertically or at an angle relative to the plug body so that the surface of the permeable membrane is at an angle to the horizontal. The catalytic devices are arranged either entirely at the same height in the vertical direction, or at least partially at the same height.

[0018] In the lead-acid battery described in (1), the catalytic device is disposed vertically or tilted relative to the plug body, which allows water recombined from the gas in the catalytic device to easily flow along the surface of the permeable membrane and return to the battery case due to the tilt of the catalytic device.

[0019] The recombination capacity required for a catalytic device depends on the amount of catalyst and the surface area of ​​the catalyst. When multiple catalytic devices are used, the amount of catalyst and surface area per catalytic device can be reduced compared to when there is only one. This allows the catalytic device to be made smaller. In this configuration, multiple miniaturized catalytic devices are placed at the same height on the liquid plug, so the overall length of the liquid plug can be shortened (the same applies when some of the catalytic devices are placed at the same height).

[0020] By shortening the overall length of the liquid plug, it is possible to ensure a sufficient distance from the liquid surface to the liquid plug, so that even if the liquid surface rises due to charging, the liquid surface is less likely to reach the liquid plug, which prevents the electrolyte from leaking through the vent hole by running down the inside of the liquid plug.

[0021] (2) In the lead-acid battery described in (1) above, the number of the catalytic devices may be two, and the catalytic devices may be arranged in the plug body with their front or back surfaces facing each other when viewed from above and below.

[0022] According to the lead-acid battery described in (2) above, two catalytic devices can be placed in the central space of the plug body, etc. Furthermore, when used with the surfaces facing each other, the two catalytic devices can be placed a predetermined distance apart. By separating the surfaces of the two catalytic devices by a predetermined distance, gas can flow in and out of the catalytic devices without being obstructed, and catalytic performance can be maintained.

[0023] (3) In the lead-acid battery described in (1) above, the number of the catalytic devices may be three or more, and the catalytic devices may be arranged in a ring shape within the plug body when viewed from above and below. Here, the ring shape refers to a configuration in which three or four catalytic devices are arranged in a polygonal shape such as a triangle or a rectangle.

[0024] According to the lead-acid battery described in (3) above, three or more catalytic devices can be placed in the space along the inner periphery of the plug body. The central space of the plug body can be used to place components for holding the catalytic devices, for example, or as a gas exhaust path.

[0025] <Embodiment 1> Embodiment 1 will be described with reference to the drawings. 1. Structure of Lead-Acid Battery 1 As shown in Figures 1 to 3, the lead-acid battery 1 includes a battery case 10, an electrode plate pack 30 which is a power-generating element, and an electrolyte 35. In the following description, the width direction of the battery case 10 (the direction in which external terminals 53A, 53B are arranged) when the battery case 10 is placed horizontally without tilting relative to a mounting surface is defined as the X direction, the up-down direction (height direction) of the battery case 10 is defined as the Z direction, and the depth direction is defined as the Y direction.

[0026] The battery case 10 includes a battery case 20 and a lid member 50. The battery case 20 is made of, for example, synthetic resin. The battery case 20 has four outer walls 21, a bottom wall 22, and is box-shaped with an open top.

[0027] As shown in Fig. 2, the interior of the battery case 20 is divided into a plurality of cell chambers 25 by partition walls 23. Six cell chambers 25 are provided in the width direction of the battery case 20 (the X direction in Fig. 2), and each cell chamber 25 contains a plate assembly 30 together with an electrolyte 35 made of dilute sulfuric acid.

[0028] 3, the electrode plate assembly 30 is composed of a positive electrode plate 30A, a negative electrode plate 30B, and a separator 30C separating the two electrode plates 30A, 30B. Each of the electrode plates 30A, 30B is composed of a grid filled with an active material.

[0029] The lid member 50 is made of, for example, synthetic resin, and includes a flat plate portion 51 and an outer peripheral wall 52. The flat plate portion 51 is large enough to seal the top surface of the battery case 20. The outer peripheral wall 52 extends downward from the outer periphery of the flat plate portion 51.

[0030] A lid partition (not shown) corresponding to the partition 23 is formed on the back surface of the lid member 50. The lid member 50 is attached so as to overlap the battery case 20 and is heat-welded to the battery case 20. The lid member 50 seals the top surface of the battery case 20.

[0031] The lead-acid battery 1 is provided with a positive external terminal 53A and a negative external terminal 53B. As shown in Fig. 1 , the positive external terminal 53A and the negative external terminal 53B are disposed on both sides of the cover member 50 in the X direction.

[0032] The lead-acid battery 1 further includes a liquid plug 70. The liquid plug 70 is attached to the liquid port 55 of the lid member 50. Six sets of liquid ports 55 and liquid plugs 70 are provided corresponding to the six cell chambers 25. By removing the liquid plug 70, rehydration liquid can be replenished from the liquid port 55 to each cell chamber 25 of the battery case 20.

[0033] 2. Structure of the Liquid Plug 70 As shown in FIGS. 4 and 5, the liquid plug 70 comprises a plug body 71, a packing 77, a filter 80, a splash guard 90, and two catalyst devices 100A and 100B.

[0034] The plug body 71 is made of, for example, synthetic resin, and includes a circular head 73 and an outer peripheral wall 75. The outer peripheral wall 75 extends downward from the head 73 and has a generally cylindrical shape centered on the axis Lc in the Z direction.

[0035] The outer peripheral wall 75 has a threaded portion 76 on its outer periphery. The lid member 50 has an inner wall portion 56 that corresponds to the liquid port 55. The inner surface of the inner wall portion 56 is threaded to match the threaded portion 76. The liquid plug 70 is removably fixed to the lid member 50 by screwing the threaded portion 76 into the inner wall portion 56 around the liquid port of the lid member 50.

[0036] The packing 77 is a ring-shaped member made of, for example, synthetic rubber, etc. The lower surface of the packing 77 is in close contact with the stepped surface 56A of the inner wall portion 56, ensuring airtightness around the liquid port.

[0037] As shown in Figure 5, the liquid plug 70 has an opening 75A on the underside of the outer wall 75 and an exhaust hole 73A in the head 73. The opening 75A is an inlet for introducing gas G generated in the cell chamber 25 into the liquid plug. The exhaust hole 73A is provided for exhausting the gas G to the outside. The gas G is oxygen gas or hydrogen gas generated in the cell chamber 25 by, for example, electrolysis of water due to charging.

[0038] The liquid stopper 70 holds a filter 80, a splash guard 90, and two catalytic devices 100A and 100B inside. Specifically, from top to bottom, the filter 80, the two catalytic devices 100A and 100B, and the splash guard 90 are held in this order.

[0039] 5, the filter 80 is located inside the head portion 73. The filter 80 is a porous body made of a sintered ceramic such as alumina or a sintered resin particle such as polypropylene.

[0040] The filter 80 is an explosion-proof filter that removes electrolyte spray from the gas G and prevents sparks and the like generated outside from penetrating into the battery case 20. The filter 80 may be omitted.

[0041] 6 and 7, the catalytic devices 100A and 100B are composed of a case 110, a catalyst layer 120, and a permeable membrane 130. The case 110 is made of resin and is cylindrical with a bottom.

[0042] The catalyst layer 120 is located inside the case 110. The catalyst layer 120 promotes the recombination reaction of oxygen gas and hydrogen gas (the reaction that converts them back into water).

[0043] The permeable membrane 130 is located on the surface of the case 110 and covers the catalyst layer 120. The permeable membrane 130 is porous and allows oxygen gas, hydrogen gas, and water vapor to pass through. The permeable membrane 130 is preferably made of a material that does not react with the electrolyte solution inside the battery, and one example of such a material is porous PTFE.

[0044] As shown in Figures 8A and 8B, the catalytic device 100 is attached vertically to the plug body 71 so that the surface on which the permeable membrane 130 that allows gas G to pass is provided is at 90 degrees to the horizontal direction (left and right direction in Figure 8).

[0045] In this embodiment, as shown in Figure 8A, the two catalytic devices 100A and 100B are positioned at the same height, with the upper end 101 and lower end 103 positioned at points P1 and P2 in the Z direction (up and down direction), respectively.

[0046] The two catalytic devices 100A, 100B only need to be at least partially at the same height (overlapping) in the Z direction when viewed horizontally (left and right in Figure 8), and the positions of the upper end 101 and the lower end 103 may be offset in the Z direction as shown in Figure 8B. "D" in Figure 8B indicates the height offset.

[0047] 9 is a horizontal cross-sectional view of the liquid plug 70. In this embodiment, two catalytic devices 100A and 100B are arranged at a predetermined distance V apart, with their permeable membranes 130 facing each other. Specifically, they are arranged facing each other in parallel.

[0048] In this embodiment, the two catalytic devices 100A, 100B are held within the plug body by sandwiching the outer peripheries of the catalytic devices 100A, 100B between the outer periphery wall 75 of the plug body 70. Grooves 78 may also be provided to regulate the positions of the catalytic devices 100A, 100B relative to the outer periphery wall 75.

[0049] As shown in Fig. 9, the two catalytic devices 100A and 100B do not overlap each other in horizontal cross section, but are spaced apart. If they overlap, water droplets formed by catalytic reactions may adhere to the surface of the other catalytic device, resulting in a decrease in catalytic performance. In particular, if the positions of the two catalytic devices 100A and 100B are misaligned in the vertical direction (see Fig. 8B), water droplets formed by catalytic reactions in the upper catalytic device 100A may adhere to the surface of the lower catalytic device 100B, resulting in a decrease in catalytic performance (see Fig. 8B). By arranging the two catalytic devices 100A and 100B with the surfaces of the permeable membranes 130 spaced apart, as shown in Fig. 9, the decrease in catalytic performance due to water adhesion can be suppressed.

[0050] The splash guard 90 is made of, for example, resin. As shown in Fig. 5, the splash guard 90 includes a bottom 91, a support 92, a first splash guard plate 93, a second splash guard plate 94, a third splash guard plate 95, and a fourth splash guard plate 96. The number of splash guard plates is not limited to four, and may be, for example, five or six.

[0051] Because the splash guard 90 has the first splash guard plate 93 to the fourth splash guard plate 96, the exhaust path for the gas G inside the plug body 71 is labyrinth-shaped, and the electrolyte 35 easily reaches the exhaust hole 73A and does not leak out to the outside.

[0052] In this embodiment, the upper part of the splash guard 90 abuts against the bottom parts of the two catalytic devices 100A, 100B, and it also functions to support the two catalytic devices 100A, 100B within the plug body.

[0053] The splash guard 90 is not configured to close the internal space of the plug body 71, but has gaps at locations other than the cross section of FIG. 5 that allow the gas G to move.

[0054] 3. Description of Effects In the lead-acid battery 1 described in this embodiment, the two catalytic devices 100A, 100B are attached vertically to the liquid stopper 70. Therefore, the water recombined from the gas G in the catalytic devices 100A, 100B moves downward along the surface of the permeable membrane 130 due to the inclination of the catalytic devices 100A, 100B, and is therefore more likely to return to each cell chamber 25 of the battery casing 20.

[0055] Furthermore, the recombination capacity required for a catalytic device depends on the amount of catalyst and the surface area of ​​the catalyst. When multiple catalytic devices (two, 100A and 100B, in this embodiment) are used, the amount of catalyst and surface area per catalytic device can be reduced (approximately half the amount of catalyst and approximately half the surface area in this embodiment). This allows the catalytic devices 100A and 100B to be made smaller.

[0056] In the lead-acid battery 1, two miniaturized catalytic devices 100A and 100B are housed in the liquid plug 70, and the catalytic devices 100A and 100B are arranged at the same height overall, which allows the length Lz (see FIG. 5 ) of the outer peripheral wall 75 of the liquid plug 70 to be shortened.

[0057] By shortening the length Lz (see Figure 5) of the outer wall 75 of the liquid plug 70, it is possible to ensure the distance W from the liquid level 35A to the liquid plug 70, as shown in Figure 3, so that even if the liquid level 35A rises due to charging, etc., the liquid level 35A is less likely to reach the liquid plug 70.

[0058] By preventing the liquid surface 35A from reaching the liquid level 35, the electrolyte 35 can be prevented from leaking out of the exhaust hole 73A through the inside of the liquid plug 70.

[0059] Furthermore, according to the lead-acid battery 1, the catalytic devices 100A, 100B are arranged at a predetermined distance from each other, so even if two catalytic devices 100A, 100B are arranged in the plug body 70, the gas G ventilation is not impaired, and an increase in internal pressure due to poor gas G ventilation can be suppressed.

[0060] Furthermore, by arranging the surfaces on which the permeable membranes 130 are installed facing each other, the gas G passing through the exhaust path between the two catalytic devices 100A, 100 and heading toward the exhaust hole 73A can be efficiently converted back into water.

[0061] <Embodiment 2> In embodiment 1, the two catalytic devices 100A, 100B are arranged above the liquid stopper 70, and the splash guard 90 is arranged below. In embodiment 2, the up-down arrangement of the catalytic device 100 and the splash guard 90 is reversed, and the splash guard 90 is arranged above the liquid stopper 170, and the two catalytic devices 100A, 100B are arranged below.

[0062] 10, the liquid plug 170 includes a plug body 171, a packing 77, a filter 80, a splash guard 190, and two catalytic devices 100A and 100B. The plug body 171 has a head 173 and a cylindrical outer wall 175 that is open at the bottom.

[0063] The liquid plug 170 holds the filter 80, the splash guard 190, and the two catalytic devices 100A and 100B inside the plug body 171. Specifically, from top to bottom, the filter 80, the splash guard 190, and the two catalytic devices 100A and 100B are held in this order.

[0064] As shown in FIG. 10, the two catalytic devices 100A, 100B are arranged parallel to each other with a predetermined distance V between them, with their back surfaces (bottom surfaces 110A of the cases 110) facing each other.

[0065] In the second embodiment, the two catalytic devices 100A and 100B are held by a rectangular support 195 installed in the center of the outer wall 175 and the liquid plug 170. In this example, the support 195 is integrated with the splash guard 190, but it may be a separate part. The catalytic devices 100A and 100B may be held by a different structure.

[0066] In addition, although embodiment 2 shows a form in which the entire catalytic device 100A, 100B is housed in the liquid plug 170, this is not limited to a form in which the entire catalytic device 100A, 100B is housed, and part of the catalytic device 100A, 100B may protrude from the underside of the liquid plug 170.

[0067] <Other Embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included within the technical scope of the present invention.

[0068] (1) In the first embodiment, the lead-acid battery is used for four-wheeled vehicles and two-wheeled vehicles, but the applications are not limited to the examples of the embodiment. Furthermore, the arrangement of the cell chambers 25 of the lead-acid battery may differ from that disclosed in the first embodiment, for example, a matrix arrangement of three rows in the depth direction and two columns in the width direction. Matrix-arranged lead-acid batteries are sometimes used in large vehicles such as buses. The present invention can also be applied to lead-acid batteries in which the cell chambers 25 are arranged in a matrix.

[0069] (2) In the first embodiment, one form of the liquid plug 70 is shown in which the head 73 protrudes from the top surface of the lid member 50 (the head 73 is attached and detached by turning it with the fingers). The shape of the liquid plug 70 is not limited to the form shown in the first embodiment. For example, the liquid plug 70 may be in a form in which the head 73 does not protrude from the top surface of the lid member 50 (the head 73 is attached and detached by inserting a coin into a groove such as a cross formed in the head 73).

[0070] (3) In the first embodiment, the two catalytic devices 100A, 100B are housed vertically relative to the liquid plug 70. As shown in Fig. 12, the two catalytic devices 100A, 100B may be housed at an angle relative to the liquid plug 70. The angle θ of the surface of the catalytic device 100A, 100B (the surface of the permeable membrane 130) relative to the horizontal line H is greater than 0 degrees and less than 180 degrees (0 < θ < 180).

[0071] (4) In the first embodiment, two catalytic devices 100A and 100B are accommodated in the liquid plug 70. Three or more catalytic devices may be arranged in the liquid plug. For example, as shown in FIGS. 13A and 13B, three catalytic devices 200A, 200B, and 200C may be arranged in the liquid plug 270. In FIG. 13A, reference numeral 271 denotes the plug body of the liquid plug 270, reference numeral 273 denotes the head of the plug body 271, and reference numeral 275 denotes the outer peripheral wall of the plug body 271. The three catalytic devices 200A, 200B, and 200C may be arranged, for example, in the shape of an equilateral triangle. In this embodiment, the three catalytic devices 200A to 200C are held in place by a protrusion 279 formed on the inner periphery of the outer peripheral wall 275 and an equilateral triangular support 275 installed in the center of the liquid plug 270. The catalytic devices 200A to 200C may be held in place by other structures.

[0072] (5) In the second embodiment, as one aspect of the liquid plug 170, two catalytic devices 100A, 100B are arranged with their back surfaces facing each other relative to the plug body 171. When arranging the catalytic devices with their back surfaces facing each other, as shown in the second embodiment, the two catalytic devices may be arranged with their back surfaces spaced apart (see FIG. 10 ), or a holding method other than that shown in FIG. 10 (for example, holding the catalytic devices using the outer peripheral wall 175 of the plug body 171) may be employed to arrange the catalytic devices 100A, 100B with their back surfaces in close contact with each other. Similarly, the two catalytic devices 100A, 100B may be arranged with their front surfaces in close contact with each other relative to the plug body 171.

[0073] (6) In the first embodiment, the gas G generated in the cell chamber 25 is introduced into the interior through the opening 75A on the underside of the liquid plug 70. As shown in Fig. 14, a slit 79 may be provided in the outer peripheral wall 75 of the liquid plug 70, and the gas G may be introduced into the interior through the slit 79 in addition to the opening 75A on the underside of the liquid plug.

[0074] 1 Lead-acid battery 10 Battery case 20 Battery case 50 Lid member 70 Liquid stopper 71 Stopper body 80 Filter 90 Splash guard 100A, 100B Catalytic device 110 Case 120 Catalyst layer 130 Permeable membrane

Claims

DEPCT691. A lead-acid battery comprising: a battery casing; electrode plates housed within the casing; electrolyte solution housed within the casing; and a vent cap attached to the casing, which includes a tubular body, a splash guard positioned within the body, and more than one catalytic device supporting the reaction that generates water from the gas produced by the charge-discharge reaction. Each of the more than one catalytic device includes a cylindrical casing with an open front surface, a catalytic layer housed within the casing, and a permeable membrane covering the front surface of the catalytic layer and allowing gas to flow through. Each of the more than one catalytic device is arranged vertically or tilted relative to the vent cap body so that the front surface provided with the permeable membrane is angled relative to the horizontal, and in the up-down direction.

1. A lead-acid battery, where all or at least some of the more than one catalytic devices are arranged at the same height.

2. A lead-acid battery, according to claim 1, where the number of catalytic devices is two and, when viewed in the up-down direction, the two catalytic devices are arranged with their front or back surfaces facing each other in the vent body.

3. A lead-acid battery, according to claim 1, where the number of catalytic devices is three or more and, when viewed in the up-down direction, the catalytic devices are arranged in a circular pattern in the vent body.

4. A vent for use in lead-acid batteries, comprising: a tubular vent body with an open bottom surface; a splash guard positioned inside the vent body; and more than one catalytic device supporting the gas-water-generating reaction, where each of the more than one catalytic device includes a cylindrical housing with an open front surface, and a catalytic layer contained within the housing.And the permeable membrane, which is positioned on the front surface of the housing and through which the gas flows, each of the more than one catalytic device is arranged vertically or tilted relative to the stopper body so that the front surface of the permeable membrane has an angle relative to the horizontal direction, and in the axial direction of the stopper body, whether all or at least part of the more than one catalytic device is arranged at the same height;