Lead-acid battery

Abstract

To prevent variation in electrolyte level among cell chambers and reduction of electrolyte in each of the cell chambers.SOLUTION: A lead-acid battery 1 has a plurality of cell chambers 13 each housing electrodes (a positive electrode plate 19a and a negative electrode plate 19b) and an electrolyte 50. The lead-acid battery 1 comprises: a mutual passage part 26 which forms a mutual passage 26a for discharging, from a mutual exhaust port 35b to the outside, gas generated in each of the cell chambers 13; an individual passage part, provided in each of the cell chambers 13, which forms an individual passage 27a for individually bringing each of the cell chambers 13 into communication with the mutual passage 26a; a first filter 36b which is disposed at a position, in the mutual passage 26a, where the gas generated in each of the cell chambers 13 mutually passes through; an on-off valve (a valve body 36c and a valve seat 36h) which is disposed at a position, in the mutual passage 26a, where the gas generated in each of the cell chambers 13 mutually passes through, and which is opened by the pressure of the gas; and a second filter 37 which is disposed in the individual passage 27a.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a lead-acid battery. [Background technology]

[0002] Generally, a lead-acid battery has multiple cell chambers that house electrodes and electrolyte, and gas generated in each cell chamber (e.g., water evaporated from the electrolyte) is exhausted to the outside from an exhaust port. When the gas generated in each cell chamber is exhausted to the outside, the electrolyte decreases. Therefore, when the electrolyte decreases to a certain level, it is necessary to replenish each cell chamber with purified water. To reduce the frequency of this operation, it is preferable to suppress the decrease in electrolyte.

[0003] For this reason, in a conventional lead-acid battery having a common passage for exhausting gas generated in each cell chamber to the outside from a common exhaust port and a filter disposed in the common passage, an on-off valve is disposed in the common passage, and the on-off valve increases the exhaust resistance of the common passage to suppress the decrease in electrolyte (see, for example, Patent Document 1). Specifically, the lead-acid battery described in Patent Document 1 has a battery case with an open top, an inner lid that closes the opening of the battery case, and an upper lid that is disposed on the inner lid. In this lead-acid battery, a common passage and individual passages that individually communicate each cell chamber with the common passage are formed between the inner lid and the upper lid, and a filter and a passage on-off valve are disposed in the common passage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-17460 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the lead-acid battery described in Patent Document 1 has room for improvement in terms of suppressing variations in the electrolyte level between cell chambers and reduction of the electrolyte in each cell chamber. This specification discloses a technique for suppressing the variation in electrolyte level between cell chambers and the reduction in electrolyte in each cell chamber. [Means for solving the problem]

[0006] a common passage portion forming a common passage for exhausting gas generated in each of the cell chambers to the outside from a common exhaust port; an individual passage portion provided for each of the cell chambers and forming an individual passage individually connecting the cell chamber with the common passage; a first filter disposed in the common passage at a position through which the gas generated in each of the cell chambers passes in common; an on-off valve disposed in the common passage at a position through which the gas generated in each of the cell chambers passes in common, the on-off valve being opened by the pressure of the gas; and a second filter disposed in each of the individual passages. Effect of the Invention

[0007] This makes it possible to suppress variations in the electrolyte level between the cell chambers and reduction in the electrolyte in each cell chamber. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a lead-acid battery according to a first embodiment; [Diagram 2] Perspective view of the battery case [Diagram 3] A perspective view of the cover member from below. [Figure 4] Cross-section of a lead-acid battery [Diagram 5] Cross-section of a lead-acid battery [Figure 6] Cross-section of a lead-acid battery [Figure 7] Cross-sectional view of line AA shown in Figure 4 [Figure 8] Perspective view of module components [Figure 9] Cross-section of module components [Figure 10] Perspective view of module components [Figure 11] Exploded perspective view of a valve-equipped filter [Figure 12] Perspective view of the vent plug [Figure 13] Cross-section of the liquid outlet plug [Figure 14] Perspective view of splash guard DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (Outline of this embodiment) (1) According to one aspect of the present invention, a lead-acid battery having a plurality of cell chambers containing electrodes and an electrolyte includes: a common passage portion forming a common passage for exhausting gas generated in each of the cell chambers to the outside from a common exhaust port; individual passage portions provided for each of the cell chambers and forming individual passages individually connecting the cell chambers to the common passage; a first filter disposed in the common passage at a position through which the gas generated in each of the cell chambers passes in common; an on-off valve disposed in the common passage at a position through which the gas generated in each of the cell chambers passes in common, the on-off valve being opened by pressure of the gas; and a second filter disposed in each of the individual passages.

[0010] The above phrase "exhausting to the outside from a common exhaust port" means that gas generated in each cell chamber is exhausted to the outside from the same exhaust port. The lead-acid battery described in the above-mentioned Patent Document 1 does not have filters in the individual passages, so the distance from each cell chamber to the filter (the filter arranged in the common passage) varies depending on the cell chamber. The inventors of the present application found that if the distance from each cell chamber to the filter varies depending on the cell chamber, the liquid level of the electrolyte is likely to vary between the cell chambers. Specifically, in a cell chamber with a short distance to the filter, gas is more likely to reach the filter than in a cell chamber with a long distance to the filter, so the electrolyte is more likely to be reduced. For this reason, the liquid level of the electrolyte is likely to vary between the cell chambers. In the case of lead-acid batteries installed in automobiles, the cell chambers at the ends are easily affected by engine heat, so the fluid loss in the cell chambers at the ends is likely to progress. For this reason, the fluid level between the cell chambers can vary due to the influence of engine heat.

[0011] In the above-mentioned lead-acid battery, not only the first filter is disposed in the common passage, but also the second filter is disposed in the individual passage. When the second filter is disposed in the individual passage, the distance from each cell chamber to the second filter becomes uniform, so that the reduction of the electrolyte tends to become uniform. Therefore, the variation in the electrolyte level can be suppressed compared to the lead-acid battery described in Patent Document 1. Even if the electrolyte level varies due to the influence of heat, the second filter makes it difficult for gas to pass through, so that the variation in the electrolyte level can be suppressed.

[0012] Furthermore, the inventors of the present application found that the lead-acid battery described in the above-mentioned Patent Document 1 is prone to electrolyte loss even if an on-off valve is provided in the common passage because filters are not provided in the individual passages. Specifically, if filters are not provided in the individual passages, the pressure in each cell chamber is unlikely to increase even if an on-off valve is provided in the common passage. For this reason, it takes time for the pressure in the cell chamber to reach saturated vapor pressure (pressure at which gas returns to liquid). If it takes time to reach saturated vapor pressure, the amount of gas passing through the filter (filter provided in the common passage) increases during that time, and electrolyte is likely to be lost.

[0013] In the above lead-acid battery, in addition to the first filter and the on-off valve being disposed in the common passage, the second filter is also disposed in the individual passage, so that the exhaust resistance is larger than that of the lead-acid battery described in Patent Document 1. Therefore, the pressure in the cell chamber rises to the saturated vapor pressure in a shorter time than that of the lead-acid battery described in Patent Document 1, and the electrolyte is less likely to decrease. Therefore, compared to the lead-acid battery described in Patent Document 1, the above-mentioned lead-acid battery can suppress variations in the electrolyte level between the cell chambers and reduction in the electrolyte in each cell chamber.

[0014] (2) According to one aspect of the present invention, the lead-acid battery may include a battery case whose interior is divided into a plurality of cell chambers and which is open on the upper side, and a cover member that covers the opening, the cover member having the common passage portion integrally formed therewith.

[0015] The lead-acid battery described in the above-mentioned Patent Document 1 includes an inner lid and an outer lid, and a common passage is provided between the inner lid and the outer lid. That is, the lead-acid battery described in Patent Document 1 has a double-layered lid. Therefore, the number of parts increases compared to when the lid has a single-layered lid. According to the above-mentioned lead-acid battery, the common passage portion is integrated into the lid member, so the lid member does not need to have a double-layered structure. Therefore, the number of parts can be reduced.

[0016] (3) According to one aspect of the present invention, the cover member has a liquid inlet provided above each of the cell chambers and a liquid inlet plug for plugging the liquid inlet, the common passage portion has a first cylindrical portion provided for each of the liquid inlets, the first cylindrical portion surrounding the liquid inlet and extending cylindrically downward from a lower surface of the cover member, and a communicating passage portion forming a communicating passage connecting adjacent first cylindrical portions, the individual passage portion is provided integrally with the liquid inlet plug, and is a second cylindrical portion extending cylindrically downward from a lower surface of the liquid inlet plug, the second filter is housed therein, and the second cylindrical portion has an opening formed on an outer peripheral surface, a portion of the second cylindrical portion below the opening is in close contact with an inner peripheral surface of the first cylindrical portion, and gas flowing into the interior of the second cylindrical portion may pass through the second filter and flow from the opening into the common passage.

[0017] In the lead-acid battery described above, since the second filter is disposed in the individual passage, the distance from each cell chamber to the second filter is uniform, which makes it easier for the electrolyte to be reduced in a uniform manner and suppresses the variation in the electrolyte level. Furthermore, in the lead-acid battery, since the second filter is also provided in the individual passage, the exhaust resistance is larger than when the second filter is not provided in the individual passage, and therefore the electrolyte is less likely to decrease.

[0018] (4) According to one aspect of the present invention, the first filter and the on-off valve are modularized as a single component, and the component may include a blocking member that blocks an opening of the common passage and in which the exhaust port is formed, and the component may be attached to the inside of the common passage from the outside.

[0019] The lead-acid battery described in the above-mentioned Patent Document 1 has a double-structure lid. When the lid has a double structure, the inside of the common passage can be easily accessed by removing the top lid before the inner lid and the top lid are joined by thermal welding or the like. This makes it easy to arrange a first filter and an on-off valve in the common passage. In contrast, the above-mentioned lead-acid battery has a cover member with a single structure. When the cover member has a single structure, it is difficult to access the inside of the common passage, and therefore it is difficult to dispose the first filter and the on-off valve inside the common passage. In the above-described lead-acid battery, the first filter and the on-off valve are modularized as a single component, and thus by arranging the component in the common passage from the outside, the task of arranging the first filter and the on-off valve in the common passage becomes easy.

[0020] (5) According to one aspect of the present invention, the part may include a bottomed, cylindrical third cylindrical portion surrounding the exhaust port and extending from the blocking member to the inside of the lead-acid battery, the tip side of the third cylindrical portion being blocked; a bottomed, cylindrical fourth cylindrical portion formed integrally below the third cylindrical portion and opening downward, the fourth cylindrical portion having an opening formed in a ceiling wall of the fourth cylindrical portion that communicates between an internal space of the third cylindrical portion and an internal space of the fourth cylindrical portion; a cylindrical filter case housed inside the fourth cylindrical portion, the first filter being housed inside the filter case and a plate-shaped valve body being housed below the first filter; and a valve seat formed integrally at a lower end of the filter case, on which the valve body is seated in a horizontal position, and the on-off valve may be opened when the valve body is lifted upward by gas that has flowed into the common passage from the cell chamber.

[0021] In the above-described lead-acid battery, the first filter and the on-off valve are modularized as a single component, and thus by arranging the component in the common passage from the outside, the task of arranging the first filter and the on-off valve in the common passage becomes easy.

[0022] <Embodiment 1> The first embodiment will be described with reference to Figures 1 to 14. In the following description, the front-rear direction, left-right direction, and up-down direction are based on the front-rear direction, left-right direction, and up-down direction shown in Figure 1. In the following description, the reference numerals in the drawings may be omitted for the same components, with some exceptions.

[0023] (1) Structure of lead-acid batteries A lead-acid battery 1 according to the first embodiment will be described with reference to Fig. 1. The lead-acid battery 1 is mounted on an automobile and supplies power to an engine starting device (starter motor) and auxiliary devices (electric power steering, electric brakes, headlights, air conditioner, etc.). The lead-acid battery 1 is a flooded lead-acid battery, and includes a synthetic resin battery case 10 that opens on the top, and a synthetic resin lid member 11 that closes the opening of the battery case 10.

[0024] 2, the battery case 10 has a rectangular shape when viewed from above, and has five partition walls 12 formed therein at equal intervals in the left-right direction. The partition walls 12 divide the inside of the battery case 10 into six cell chambers 13.

[0025] As shown in Fig. 1, the cover member 11 has a frame 14 extending downward from four sides. A protruding portion 15 that protrudes upward in a T-shape is formed on the cover member 11. A positive electrode external terminal 16 is fixed to one of two corners on the top surface of the cover member 11 where the protruding portion 15 is not formed, and a negative electrode external terminal 17 is fixed to the other corner.

[0026] 3, the protruding portion 15 of the cover member 11 is formed as a recess that is recessed upward in a T-shape when viewed from below. Five partition walls 18 are formed on the back surface of the cover member 11 in correspondence with the partition walls 12 formed on the battery case 10. 4, the lower end surface of the partition wall 18 formed on the back surface of the cover member 11 is connected to the upper end surface of the partition wall 12 formed on the battery case 10 by thermal welding or the like. This separates the cell chambers 13.

[0027] Each cell chamber 13 contains an electrode plate group 19 and an electrolyte solution 50 made of dilute sulfuric acid. The electrode plate group 19 is made up of positive electrode plates 19a and negative electrode plates 19b that are alternately stacked in the horizontal direction with a separator 19c sandwiched between them. Each of the electrode plates 19a, 19b is made up of a grid filled with an active material. The positive electrode plates 19a and negative electrode plates 19b are examples of electrodes.

[0028] As shown in Fig. 5, the upper end of each of the electrode plates 19a, 19b is provided with a lug 20. As shown in Fig. 4, the electrode plates 19a, 19b of the same polarity in one cell chamber 13 are connected at the lug 20 by a strap 21. The strap 21 is, for example, a plate that is long in the left-right direction, and one set of straps 21 is provided for each cell chamber 13, one for the positive electrode and one for the negative electrode. As shown in Fig. 2, an opening 22 is formed in the partition wall 12. As shown in Fig. 4, the positive and negative straps 21 of adjacent cell chambers 13 are connected by welding or the like through the opening 22. This connects the electrode plate groups 19 of each cell chamber 13 in series.

[0029] The positive electrode external terminal 16 and the negative electrode external terminal 17 will be described with reference to FIG. 5. The positive electrode external terminal 16 and the negative electrode external terminal 17 have substantially the same structure, so the negative electrode external terminal 17 will be described here as an example. The negative electrode external terminal 17 includes a bushing 17a and a pole 17b. The bushing 17a is made of a metal such as a lead alloy and is formed in a cylindrical shape. The upper part of the bushing 17a protrudes upward from the upper surface of the cover member 11. The pole 17b is made of a metal such as a lead alloy and is formed in a cylindrical shape. The pole 17b is inserted inside the bushing 17a, and the lower part protrudes downward from the bushing 17a. The lower end of the pole 17b is connected to a negative electrode strap 21 housed in the leftmost cell chamber 13 by welding or the like.

[0030] 1, the T-shaped protruding portion 15 of the cover member 11 is provided with a liquid filling port 23 at a position above each cell chamber 13. The liquid filling port 23 is an opening for filling each cell chamber 13 with electrolyte 50, and is also an opening for replenishing the electrolyte 50 in the cell chamber 13 with rehydration liquid when the electrolyte 50 in the cell chamber 13 decreases. 6, the liquid inlet 23 has a circular recess 23a and an opening 23b formed in the bottom wall of the recess 23a. The liquid inlet 23 is closed by a liquid inlet plug 25. The liquid inlet plug 25 will be described later.

[0031] As shown in Fig. 3, a common passage portion 26 that forms a common passage 26a (see Fig. 7) for exhausting gas generated in each cell chamber 13 to the outside is provided on the underside of the cover member 11. As will be described in detail later, the lead-acid battery 1 also includes individual passage portions that form individual passages 27a (see Fig. 13) that individually connect each cell chamber 13 to the common passage 26a.

[0032] The vent plugs 25, the common passage 26a, and the individual passages 27a will be described in detail below. First, the common passage 26a will be described, and then the vent plugs 25 and the individual passages 27a will be described.

[0033] (1-1) Common passage 3, the common passage portion 26 has a first cylindrical portion 30 provided for each liquid injection port 23, and a communicating passage portion 31 provided between adjacent first cylindrical portions 30. The communicating passage portion 31 is also provided on the left side of the leftmost first cylindrical portion 30 and on the right side of the rightmost first cylindrical portion 30. As shown in Figure 7, the common passage 26a has an arc-shaped passage between the inner surface of the first tubular portion 30 and the outer surface of the second tubular portion 25b (described later) of the liquid outlet plug 25, and a linear communicating passage formed by the communicating passage portion 31.

[0034] As shown in Fig. 6, the first tubular portion 30 surrounds the opening 23b of the liquid pouring port 23 and extends cylindrically downward from the lower surface 11a (see Fig. 3) of the cover member 11. A screw thread 32 that projects out in a spiral shape is formed on the inner peripheral surface of the first tubular portion 30. The screw thread 32 has a length that does not complete one revolution around the inner peripheral surface of the first tubular portion 30. 3 and 6, the first cylindrical portion 30 has slits 33 formed on both the front and rear sides thereof, the slits 33 extending upward from the lower end of the first cylindrical portion 30. As shown in FIG. 4, the slits 33 are formed so that gas generated in the cell chamber 13 can flow into the inside of the first cylindrical portion 30 even if the liquid level of the electrolyte 50 is above the lower end of the first cylindrical portion 30.

[0035] As shown in Figures 6 and 7, a recess 34 is formed in the left side surface of the cover member 11, recessed in a substantially rectangular shape toward the right side. The opening of the leftmost communicating passage is formed in the wall at the back side of the recess 34 when viewed from the left side. Similarly, a recess 34 is formed in the right side surface of the cover member 11, recessed in a rectangular shape toward the left side. The opening of the rightmost communicating passage is formed in the wall at the back side of the right recess 34 when viewed from the right side. The recess 34 is part of the common passage 26a. The part of the cover member 11 that forms the recess 34 constitutes part of the common passage section 26. The position of the recess 34 is an example of a position through which gas generated in each cell chamber 13 passes in common.

[0036] A module component 35 is attached to the left recess 34. The module component 35 is a modular component consisting of a first filter 36b (see FIG. 9) described later and an on-off valve described later. The module component 35 is fixed to the cover member 11 by thermal welding or the like while being housed in the left recess 34. A synthetic resin cap 39 that closes the opening of the right recess 34 is fixed to the right recess 34 by thermal welding or the like. The cap 39 may be attached to the left recess 34, and the module component 35 may be attached to the right recess 34.

[0037] As shown in Fig. 8, the module component 35 has a plate-shaped closing member 35a that closes the opening of the left recess 34. A circular exhaust port 35b is formed in the closing member 35a. As shown in Fig. 9, a third tube portion 35c is formed on the right surface of the closing member 35a, surrounding the periphery of the exhaust port 35b and extending to the right. The third tube portion 35c is formed in a bottomed tube shape with the right side closed.

[0038] As shown in Fig. 10, the tip of the third cylindrical portion 35c is recessed such that the front and rear portions are cut out, leaving only the center portion of the upper portion, forming a front recess 35j and a rear recess 35j. An annular rib 35d is formed on the right end face of the third cylindrical portion 35c, extending from a position slightly inside the outer periphery of the third cylindrical portion 35c toward the right side. A fitting portion 35m that protrudes toward the right side is formed on a roughly arc-shaped portion of the end face of the annular rib 35d facing toward the right. The fitting portion 35m is fitted and inserted into the leftmost communication passage.

[0039] As shown in Fig. 9, a fourth cylindrical portion 35e having a bottom and opening downward is integrally formed on the lower side of the third cylindrical portion 35c. A portion of the fourth cylindrical portion 35e is also integral with the blocking member 35a. The lower end of the fourth cylindrical portion 35e is located above the lower end of the blocking member 35a. Therefore, as shown in Fig. 6, when the module component 35 is attached to the recess 34, a gap is generated between the lower end of the fourth cylindrical portion 35e and the bottom surface of the recess 34.

[0040] As shown in Fig. 9, an opening 35f is formed in the ceiling wall 35k of the fourth cylindrical portion 35e, which communicates the internal space of the third cylindrical portion 35c with the internal space of the fourth cylindrical portion 35e. Although only a portion of the opening 35f is visible in Fig. 9, four downwardly protruding protrusions 35g are formed at equal intervals in the circumferential direction of the fourth cylindrical portion 35e on the lower surface of the ceiling wall 35k of the fourth cylindrical portion 35e. A valve filter 36 is press-fitted from below into the fourth cylindrical portion 35e. The valve filter 36 includes a filter case 36a, a first filter 36b housed inside the filter case 36a, and a disk-shaped valve body 36c disposed below the first filter 36b inside the filter case 36a.

[0041] The valve function-equipped filter 36 will be described in more detail with reference to Fig. 11. The filter case 36a is made of synthetic resin and formed in a cylindrical shape. The lower part of the filter case 36a has smaller outer and inner diameters than the upper part, and a valve seat 36h on which the valve body 36c sits in a horizontal position is integrally formed at the lower end of the lower part. The valve seat 36h is formed so as to protrude inward in an annular shape from the inner circumferential surface of the lower end of the lower part of the filter case 36a. The valve body 36c and the valve seat 36h are an example of an on-off valve.

[0042] Although only a portion of the grooves 36i are visible in Fig. 11, the upper surface of the valve seat 36h is provided with three downwardly recessed grooves 36i at equal intervals in the circumferential direction. These grooves 36i are formed to extend radially outward from the center of the filter case 36a. The valve seat 36h may be provided with a protrusion that protrudes upward instead of the grooves 36i. The first filter 36b is attached for the purpose of explosion-proofing to block flames from the outside, and is formed in a disk shape having a certain thickness. Specifically, the first filter 36b is, for example, a porous body having continuous pores. Specifically, the porous body is, for example, a ceramic such as alumina or a sintered body of resin particles such as polypropylene. The average pore size of the first filter 36b is, for example, several tens to several hundreds of μm. The first filter 36b also plays a role of increasing the exhaust resistance of the gas generated in the cell chamber 13 in cooperation with the second filter 37 arranged in the individual passage 27a described later.

[0043] The valve body 36c is made of synthetic resin and is formed in a disk shape. The diameter of the valve body 36c is smaller than the inner diameter of the lower part of the filter case 36a and larger than the diameter of the opening of the valve seat 36h. When the pressure in the cell chamber 13 is low, the valve body 36c sits horizontally on the valve seat 36h due to its own weight. Since the groove 36i is formed on the upper surface of the valve seat 36h, even if the valve body 36c is seated on the valve seat 36h, a gap exists between the valve body 36c and the valve seat 36h. Due to the presence of this gap, the pressure inside the cell chamber 13 does not become lower than atmospheric pressure. For example, if the valve body 36c is in complete contact with the upper surface of the valve seat 36h, the air cannot pass through the valve body 36c when the temperature of the lead-acid battery 1 drops, and the internal pressure of the cell chamber 13 drops to become lower than atmospheric pressure. When this happens, the outer wall of the battery case 10 curves inward, and the level of the electrolyte 50 inside the battery case 10 rises, making it easier for overflow to occur. In contrast, if a gap is provided, the drop in the internal pressure of the battery case 10 when the temperature of the lead-acid battery 1 drops is suppressed, and overflow of the electrolyte 50 is suppressed.

[0044] (1-2) Liquid outlet plugs and individual passages 12, the liquid port plug 25 has a disk-shaped plug member 25a that covers the liquid inlet 23, a second cylindrical portion 25b that extends cylindrically downward from the lower surface h of the plug member 25a, and a packing 25c attached to the outer periphery of the upper end portion of the second cylindrical portion 25b. The inside of the second cylindrical portion 25b is an example of an individual passage. The second cylindrical portion 25b is an example of an individual passage portion that forms the individual passage 27a.

[0045] As shown in FIG. 1, a cross-shaped groove is formed on the top surface of the vent plug 25 for screwing the vent plug 25 into the inside of the first cylindrical portion 30 with a coin or the like. As shown in Fig. 12, the second cylindrical portion 25b is made up of an upper portion 41, a middle portion 42, and a lower portion 43. A screw thread 25d is formed on the outer circumferential surface of the middle portion 42. As shown in Fig. 6, the liquid port plug 25 inserted from the liquid filling port 23 is fixed to the cover member 11 by screwing the screw thread 25d into the screw thread 32 of the first cylindrical portion 30.

[0046] As shown in FIG. 6, the outer diameter of the upper portion 41 of the second cylindrical portion 25b is smaller than the inner diameter of the first cylindrical portion 30. Therefore, a gap is generated between the inner peripheral surface of the first cylindrical portion 30 and the outer peripheral surface of the upper portion 41 of the second cylindrical portion 25b. The outer diameter of the lower portion 43 of the second cylindrical portion 25b is also smaller than the inner diameter of the first cylindrical portion 30. Therefore, a gap is also generated between the inner peripheral surface of the first cylindrical portion 30 and the outer peripheral surface of the lower portion 43. In contrast, the middle portion 42 is in close contact with the first cylindrical portion 30.

[0047] 12, slits 25e extending upward from the lower end of the second cylindrical portion 25b are formed on both the front and rear sides of the lower portion 43. The slits 25e serve as entrances through which gas generated in the cell chamber 13 enters the interior of the second cylindrical portion 25b. The upper end of the slits 25e reaches the lower end of the thread 25d formed in the middle portion 42, and the lower end of the thread 25d is cut out at a position that overlaps with the upper end of the slits 25e.

[0048] As shown in FIG. 13, a second filter 37 is housed inside the upper portion 41 of the second cylindrical portion 25b. The second filter 37 cooperates with the first filter 36b to increase the gas exhaust resistance, and is formed in a disk shape having a certain thickness. Specifically, the second filter 37 is, for example, a porous body having continuous pores. Specifically, the porous body is, for example, a sintered body of ceramics such as alumina or resin particles such as polypropylene. The average pore size of the filter is, for example, several tens to several hundreds of μm.

[0049] 12 and 13, circular openings 25f are formed on both the front and rear sides of the upper part 41 of the second cylindrical portion 25b at positions corresponding to the outer circumferential surface of the second filter 37. The openings 25f are an example of an opening that communicates between the inside and outside of the second cylindrical portion 25b. 13, a splash guard 38 is accommodated inside the second cylindrical portion 25b below the second filter 37. The splash guard 38 is intended to allow gas generated in the cell chamber 13 to pass through, while preventing mist of the electrolyte 50 in the cell chamber 13 from reaching the second filter 37.

[0050] The splash guard 38 will be described in detail with reference to Fig. 14. The splash guard 38 is made of synthetic resin and includes a disk-shaped bottom 38a, a support 38b, and multiple splash guard plates 38c. The bottom 38a closes the lower opening of the second tubular portion 25b. The multiple splash guard plates 38c are intended to form a labyrinth-like passage inside the second tubular portion 25b (i.e., the individual passage 27a). Since the inside of the second tubular portion 25b is labyrinth-like, it becomes difficult for the mist of the electrolyte 50 generated in the cell chamber 13 to reach the second filter 37.

[0051] 12 and 13, a restricting portion 25g that restricts the vertical position of the packing 25c is integrally provided on the outer circumferential surface of the upper portion 41 of the second cylindrical portion 25b. The restricting portion 25g goes around the second cylindrical portion 25b except for the portion where the circular opening 25f of the second cylindrical portion 25b is formed.

[0052] Packing 25c is formed into a ring shape and made of synthetic rubber, etc. As shown in Fig. 6, when spout plug 25 is inserted into spout 23, the gap between the upper surface of recess 23a of spout 23 and the lower surface of disc-shaped plug member 25a is air-tightly sealed by packing 25c.

[0053] (2) Gas exhaust flow For convenience, the leftmost cell chamber 13 of the six cell chambers 13 shown in FIG. 6 will be referred to as the first cell chamber 131, and the remaining chambers will be referred to as the second cell chamber 132 to the sixth cell chamber 136 in order moving to the right. For example, taking the fourth cell chamber 134 as an example, gas generated in the fourth cell chamber 134 flows into the space between the first cylindrical portion 30 and the lower portion 43 of the second cylindrical portion 25b through the lower opening of the first cylindrical portion 30 or the slit 33 of the first cylindrical portion 30. The gas that has flowed between the first cylindrical portion 30 and the lower portion 43 of the second cylindrical portion 25b flows into the inside of the second cylindrical portion 25b (i.e., the individual passage 27a) through the slit 25e of the second cylindrical portion 25b. The gas that has flowed into the inside of the second cylindrical portion 25b passes through the labyrinth-like passage formed by the splash guard 38. The gas that has passed through the labyrinth-like passage passes through the second filter 37 and flows into the common passage 26a through the opening 25f of the second cylindrical portion 25b.

[0054] The flow of gas in the common passage 26a will be described with reference to Fig. 7. Taking the fourth cell chamber 134 as an example, gas flowing from the individual passage 27a of the fourth cell chamber 134 into the common passage 26a flows to the left in the common passage 26a. Gas generated in the cell chambers 13 to the right of the fourth cell chamber 134 (the fifth cell chamber 135 and the sixth cell chamber 136) flows to the left through the arc-shaped passage between the first cylindrical portion 30 and the second cylindrical portion 25b of the fourth cell chamber 134. For this reason, gas generated in the fifth cell chamber 135 or the sixth cell chamber 136 flows to the left without passing through the second filter 37 provided in the liquid vent plug 25 of the fourth cell chamber 134.

[0055] As shown in Figures 6 and 10, part of the gas flowing through the common passage 26a flows from the recessed portion 35j of the third cylindrical portion 35c of the module component 35 into the gap between the recessed portion 34 and the module component 35. The remaining part hits the right end face of the third cylindrical portion 35c, turns back, and flows from the recessed portion 35j of the third cylindrical portion 35c into the gap between the recessed portion 34 and the module component 35. As shown in Figure 6, there is a gap between the lower end of the fourth cylindrical portion 35e of the module component 35 and the bottom surface of the recessed portion 34, so the gas that has flowed into the gap between the recessed portion 34 and the module component 35 flows around to the underside of the plate-shaped valve body 36c. When the pressure of the gas rises to a certain value or more in this state, the valve body 36c is lifted upward by the gas, and the module component 35 opens.

[0056] When the module component 35 is opened, the gas flows upward and passes through the first filter 36b. As described above, a gap is formed between the ceiling wall 35k of the fourth cylindrical portion 35e and the first filter 36b by the protruding portion 35g, so that the gas that passes through the first filter 36b flows into the gap and flows into the third cylindrical portion 35c through the opening 35f formed in the ceiling wall 35k of the fourth cylindrical portion 35e. The gas that flows into the third cylindrical portion 35c is exhausted to the outside from the exhaust port 35b formed in the blocking member 35a.

[0057] As described above, the groove 36i is formed on the upper surface of the valve seat 36h, so that a gap is always generated between the valve seat 36h and the valve body 36c. Therefore, even if the gas pressure does not rise above a certain value, a part of the gas flows in through the gap between the valve seat 36h and the valve body 36c, passes through the first filter 36b, and is exhausted to the outside.

[0058] (3) Effects of the embodiment In the lead-acid battery 1 according to the first embodiment, not only the first filter 36b is disposed in the common passage 26a, but also the second filter 37 is disposed in the individual passage 27a. By disposing the second filter 37 in the individual passage 27a, the distance from each cell chamber 13 to the second filter 37 becomes uniform, so that the reduction of the electrolyte 50 tends to become uniform. Therefore, the variation in the liquid level of the electrolyte 50 can be suppressed compared to the lead-acid battery described in Patent Document 1. Furthermore, in the lead-acid battery 1, the first filter 36b and the on-off valve (the valve body 36c and the valve seat 36h) are disposed in the common passage 26a, and in addition, the second filter 37 is disposed in the individual passage 27a, so that the exhaust resistance is larger than that of the lead-acid battery described in Patent Document 1. Therefore, the pressure in the cell chamber 13 rises to the saturated vapor pressure in a shorter time than that of the lead-acid battery described in Patent Document 1, and the electrolyte 50 is less likely to decrease. Therefore, compared to the lead-acid battery described in Patent Document 1, the lead-acid battery 1 can suppress variations in the liquid level of the electrolyte 50 between the cell chambers 13 and reduction in the amount of the electrolyte 50 in each cell chamber 13.

[0059] According to the lead-acid battery 1, since the common passage portion 26 is integrated with the cover member 11, it is not necessary to make the cover member 11 have a double structure, and therefore the number of parts can be reduced.

[0060] In the lead-acid battery 1, the first filter 36b and the on-off valve (the valve body 36c and the valve seat 36h) are modularized as a single component, and thus, by arranging the component in the common passage 26a from the outside, the work of arranging the first filter 36b and the on-off valve in the common passage 26a becomes easy.

[0061] <Other embodiments> The technology disclosed in this specification is not limited to the embodiments described above and in the drawings, and for example, the following embodiments are also included in the technical scope disclosed in this specification.

[0062] (1) In the above embodiment, the lid member 11 has a single structure, but the lid member 11 may have a double structure consisting of an inner lid and an upper lid, similar to the invention described in Patent Document 1. In addition, a common passage and an individual passage may be formed between the inner lid and the upper lid, similar to the invention described in Patent Document 1.

[0063] (2) In the above embodiment, an example was described in which the first filter 36b is located closer to the exhaust port 35b than the on-off valve (valve body 36c and valve seat 36h). However, the on-off valve may be located closer to the exhaust port 35b than the first filter.

[0064] (3) In the above embodiment, the first filter 36b and the on-off valve are modularized as a single component. However, the first filter and the on-off valve do not have to be modularized.

[0065] (4) In the above embodiment, the valve body 36c is seated on the valve seat 36h in a horizontal position and opens due to gas pressure. However, the valve body may be configured to be seated on the valve seat with the plate surface facing horizontally. The valve body may be biased toward the valve seat by a coil spring or the like, and when the gas pressure increases, the valve body may move away from the valve seat against the biasing force of the coil spring. [Explanation of symbols]

[0066] 1...Lead acid battery 10...Battery container 11...Cover member 13. Cell room 19a...Positive electrode plate (an example of an electrode) 19b...Negative electrode plate (an example of an electrode) 23…Filling port 25…Vent plug 25b... second cylindrical portion (an example of an individual passage portion) 25f...Opening (an example of an opening that communicates the inside and outside of the second cylindrical portion) 26…Common passage section 26a…Common passage 27a…Individual aisle 30…First cylinder section 31...Communication passage section 35...Module parts (examples of parts) 35a...Blocking member 35b…Exhaust port 35c…Third barrel section 35e…fourth barrel section 35f...Opening (an example of an opening that communicates the internal space of the third cylindrical portion with the internal space of the fourth cylindrical portion) 35k…Ceiling wall 36a…Filter case 36b…First filter 36c…Valve body (an example of an on-off valve) 36h…Valve seat (an example of an on-off valve) 37…Second filter 41...Upper part 42...middle part 43…lower part 50...Electrolyte

Claims

1. A lead-acid battery having a plurality of cell chambers each containing an electrode and an electrolyte, a common passage portion that forms a common passage for exhausting gas generated in each of the cell chambers to the outside through a common exhaust port; an individual passage portion provided for each of the cell chambers and forming an individual passage that individually connects the cell chamber and the common passage; a first filter disposed in the common passage at a position through which gas generated in each of the cell chambers passes in common; an on-off valve that is disposed in the common passage at a position where the gas generated in each of the cell chambers passes through in common and that opens or closes due to pressure of the gas; a second filter disposed in each of the individual passages; A battery container having an interior divided into a plurality of cell chambers and an opening on an upper side; a cover member that closes the opening, the cover member having the common passage portion integrally formed therewith; Equipped with the cover member has a liquid inlet provided on each of the cell chambers and a liquid inlet plug for plugging the liquid inlet, the common passage portion includes a first cylindrical portion provided for each of the liquid inlets, the first cylindrical portion surrounding the liquid inlet and extending downward from the lower surface of the lid member in a cylindrical shape, and a communication passage portion forming a communication passage that communicates between adjacent first cylindrical portions, the individual passage portion is provided integrally with the vent plug, and is a second tubular portion extending cylindrically downward from a lower surface of the vent plug, the second filter is accommodated therein, and an opening is formed on an outer circumferential surface of the second tubular portion; a portion of the second cylindrical portion below the opening is in close contact with an inner circumferential surface of the first cylindrical portion, a lead-acid battery, wherein the gas that has flowed into the second cylindrical portion passes through the second filter and flows into the common passage from the opening.

2. A lead-acid battery having a plurality of cell chambers each containing an electrode and an electrolyte, a common passage portion that forms a common passage for exhausting gas generated in each of the cell chambers to the outside through a common exhaust port; an individual passage portion provided for each of the cell chambers and forming an individual passage that individually connects the cell chamber and the common passage; a first filter disposed in the common passage at a position through which gas generated in each of the cell chambers passes in common; an on-off valve that is disposed in the common passage at a position where the gas generated in each of the cell chambers passes through in common and that opens or closes due to pressure of the gas; a second filter disposed in each of the individual passages; A battery container having an interior divided into a plurality of cell chambers and an opening on an upper side; a cover member that closes the opening, the cover member having the common passage portion integrally formed therewith; Equipped with the first filter and the on-off valve are modularized as one component, The part is a blocking member that blocks an opening of the common passage, the blocking member having the exhaust port formed therein, and the part is attached to the inside of the common passage from the outside.

3. A lead-acid battery as claimed in claim 2, The part comprises: a third cylindrical portion having a bottom and a closed end, the third cylindrical portion surrounding the exhaust port and extending from the closing member to an inside of the lead-acid battery, the third cylindrical portion having a closed end at a tip side; a fourth cylindrical portion that is integrally formed below the third cylindrical portion and has a bottom and a cylindrical shape that opens downward, and an opening is formed in a ceiling wall of the fourth cylindrical portion, which connects an internal space of the third cylindrical portion with an internal space of the fourth cylindrical portion; a cylindrical filter case accommodated inside the fourth cylindrical portion, the first filter being accommodated inside the filter case, and a plate-shaped valve body being accommodated below the first filter; a valve seat formed integrally with a lower end portion of the filter case, on which the valve body is seated in a horizontal position; Equipped with the valve body is lifted upward by gas flowing from the cell chamber into the common passage, thereby opening the on-off valve.

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