JP2011171039A - Vent plug for lead-acid battery and lead-acid battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lead-acid battery having high reliability in which clogging of a porous filter arranged as a flame arrestor is suppressed and a pressure release valve arranged in parallel to the porous filter is stably operated, in the lead-acid battery; and to provide a vent plug of the lead-acid battery. <P>SOLUTION: The inside of the vent plug fit to a liquid opening of the lead-acid battery is divided into four or more exhaust hoods communicating with each other by gaps, two opening parts are formed in the exhaust hood arranged beyond one or more exhaust hoods from the exhaust hood communicating with the battery, the porous filter is arranged to cover one opening part, an exhaust cylinder is formed in the other opening part, and a cap-like valve is fit to the tip of the exhaust cylinder. The opening area S of the opening part on the side facing the porous filter is limited to less than the bottom area D of the porous filter, and the opening area of the opening part corresponding to the exhaust cylinder is limited to the area smaller than an internal circumference area. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust plug for a lead storage battery and a lead storage battery equipped with the exhaust plug.

  When the lead storage battery is charged, water in the electrolytic solution is electrolyzed, and hydrogen gas and oxygen gas are generated therein. Therefore, these oxygen gases are absorbed by the negative electrode to suppress the generation of hydrogen gas at the negative electrode, or the catalyst is used to recombine hydrogen and oxygen to return them to water. Furthermore, these gases are released into the atmosphere. An exhaust path is provided in the battery.

  In liquid lead-acid batteries, a configuration in which an exhaust plug with a built-in exhaust path is attached to the lid is widely adopted, but if there is a fire point such as an electric spark or cigarette near the exhaust plug, it is included in the gas There is a possibility that the hydrogen gas is ignited and this flame is drawn into the battery through the exhaust path, and the hydrogen gas staying inside the battery is ignited to damage the battery exterior parts such as the battery case and the lid.

  Therefore, in order to prevent the flame from being drawn into the battery from the outside, it is common to install a porous filter as a flame arrester on the gas exhaust path inside the exhaust plug. As the porous filter, those obtained by sintering ceramic particles such as alumina and rigid resin particles such as polypropylene resin are mainly used. The porous filter has fine voids that are refracted inside, and the gas inside the battery can be exhausted through the voids, and the flame generated outside propagates through the voids of the porous filter. By absorbing or dissipating the heat energy of the flame, the propagation of the flame into the battery can be suppressed.

  On the other hand, since there is an electrolyte solution (dilute sulfuric acid) inside the battery, the gas inside the battery contains moisture, and electrolysis occurs when the battery is charged with gassing from the electrode plate or when vibration is applied to the battery. There is a problem that liquid droplets are condensed inside the porous filter and clog the porous filter. When the porous filter is clogged (excessive increase in pressure loss), the internal pressure of the battery increases excessively, which may deform the battery case or the lid, or damage the battery.

  In order to suppress the deformation or breakage of the battery due to such clogging of the porous filter, Patent Document 1 discloses that an explosion-proof filter made of a porous material such as ceramic and a safety valve are arranged in parallel in the exhaust path in the exhaust plug. An intervening lead acid battery is shown. With the configuration of Patent Document 1, even if the explosion-proof filter is clogged, the gas is discharged out of the battery through the safety valve, so that deformation and breakage of the battery can be suppressed.

Japanese Utility Model Publication No. 63-109441

  However, in the configuration shown in Patent Document 1, since the lower part of the explosion-proof filter and the safety valve in the exhaust path faces the electrolyte, the splash of the electrolyte easily adheres to the explosion-proof filter and the safety valve. In addition to sulfuric acid, the electrolyte contains non-volatile components such as oil eluted from the separator, so these substances clog the explosion-proof filter, or the safety valve, which is a rubber body, is altered, and the valve opening pressure of the safety valve is unstable. There was a problem.

  The present invention solves the above-described problem, and suppresses clogging of a porous filter having a function as a frame arrester, and the opening pressure of a pressure release valve arranged in parallel with the porous filter is reduced. A stabilized exhaust plug for a lead storage battery and a lead storage battery are provided.

  In order to solve the above-mentioned problem, the invention of claim 1 of the present invention is an exhaust plug for a lead storage battery that is attached to a liquid port of a lead storage battery and has an exhaust structure therein. A first exhaust pipe that hangs down toward the electrolyte surface in a state attached to the liquid port, a bottom wall disposed at one end of the first exhaust pipe in the battery inner direction, and a first exhaust pipe A middle wall disposed at one end in the battery outer direction, a shaft hanging from the central region of the middle wall toward the bottom wall, and radially disposed from the shaft toward the inner wall of the first exhaust stack; The first exhaust cylinder includes n partition walls that divide the interior of the first exhaust cylinder into at least n (n ≧ 4) exhaust chambers, and the bottom wall has an inclination angle θ (0 ° <θ with respect to the electrolyte surface). <90 °) and the adjacent exhaust chambers communicate with each other via a gap disposed between the partition wall and the bottom wall The first exhaust cylinder corresponding to the exhaust chamber closest to the electrolyte surface among the plurality of exhaust chambers has a first opening, and corresponds to the first opening of the inner wall A second opening and a third opening penetrating through the middle wall at a portion corresponding to the exhaust chamber disposed at a position separating at least one other exhaust chamber from the exhaust chamber, and the middle wall A porous filter arranged to face the bottom surface in the battery outer direction and to cover the second opening, and to communicate with the third opening and to protrude from the inner wall toward the battery outer side An opening on the side of the second opening facing the porous filter, the pressure relief valve comprising a second exhaust cylinder and a cap-like valve body attached to the second exhaust cylinder The area S is limited to be less than the bottom area D of the porous filter, and the third opening The opening area of the portion 2f is limited to be smaller than the inner peripheral area of the second exhaust pipe 6, and includes an upper cover having a large number of the cap-shaped valve body and the porous filter and a fourth opening for gas discharge. The exhaust plug for lead acid batteries provided with this is shown.

  Further, the invention according to claim 2 of the present invention is the exhaust plug for the lead storage battery according to claim 1, wherein the valve opening pressure of the pressure release valve is set higher than the initial value of the pressure loss of the porous filter. It is characterized by that.

  According to a third aspect of the present invention, in the lead-acid battery exhaust plug according to the first or second aspect, the opening area S is limited to 20% or less of the bottom area D. .

  The invention of claim 4 of the present invention shows a lead-acid battery provided with an exhaust plug having the configuration of claim 1, 2 or 3.

  Further, the invention of claim 5 of the present invention is the lead storage battery of claim 4, wherein either one of the positive electrode and the negative electrode lattice is made of a lead alloy containing antimony.

  According to the present invention, the clogging of the porous filter built in the exhaust plug attached to the lead storage battery is suppressed, and the operation of the pressure release valve that operates when the clogging of the porous filter occurs is stabilized. By this, there exists a remarkable effect that the exhaust plug for lead acid batteries excellent in reliability and a lead acid battery provided with the same can be provided.

The figure which shows the exhaust plug for lead acid batteries of this invention The figure which shows the cross section of the exhaust plug for lead acid batteries of this invention The figure which shows the other cross section of the exhaust plug for lead acid batteries of this invention The figure which shows the lead acid battery of this invention The figure which shows the cross section of the exhaust plug for lead acid batteries of a comparative example

(First embodiment of the present invention)
Hereinafter, the structure of the exhaust plug for a lead storage battery according to the first embodiment of the present invention will be described. The exhaust plug 1 of the present invention is attached to the liquid port 12 of the lead storage battery 11 shown in FIG. 4 and has an exhaust structure inside. FIG. 1 is a view showing the appearance of the exhaust plug 1, and has a mounting structure on the outer periphery of the lead storage battery with the liquid port 12 shown in FIG. 4. Although FIG. 1 shows an example in which the screw portion 1a that is screwed into the liquid port 12 is arranged as the mounting structure, other mounting structures may be used.

  The exhaust plug 1 of the present invention has a first exhaust pipe 2 that hangs down toward the electrolyte surface (the phantom line A shown in FIG. 1) by being attached to the liquid port. FIG. 2 is a view showing a cross section of the exhaust plug 1 for the lead storage battery of the present invention. FIG. 3 is a view showing a cross section when the exhaust plug 1 is cut along the line BB ′ in FIG. 2.

  As shown in FIG. 2, an inclination angle θ (0 ° <θ <90 °) with respect to the electrolyte surface at one end of the first exhaust stack 2 in the battery inner direction, that is, at an end protruding in the electrolyte surface direction. ) Is disposed. Further, the other end of the first exhaust pipe 2 is provided with a middle wall 4. The selection of θ may be an angle that is sufficient for the droplets condensed in the exhaust chamber 2b to spontaneously fall due to gravity and be guided to the first opening 2d. It can be in the range of °.

  4 has a shaft 5 that hangs down from the central region of the middle wall 4 toward the bottom wall 3, and is arranged radially from the shaft 5 toward the inner wall 2a of the first exhaust pipe 2, as shown in FIG. A single partition wall 5a is provided. Therefore, the internal space of the exhaust tube 2 is partitioned into four exhaust chambers 2b-1, 2b-2, and 2b-3 by the four partition walls 5a. In FIG. 3, one exhaust chamber 2 b-1, two exhaust chambers 2 b-2, and one exhaust chamber 2 b-3 are collectively referred to as an exhaust chamber 2 b.

  In FIG. 3, the number n of the partition walls 5a is four, but n may be four or more, and more preferably an even number of four or more. Therefore, the internal space of the exhaust tube 2 is partitioned into n exhaust chambers 2b by partition walls 5a of n (n ≧ 4) or more. By setting the number of exhaust chambers 2b to 4 or more, the gas to be discharged from the battery collides with at least two partition walls 5a, so that the electrolytic droplets contained in the gas can be efficiently removed. . When the number of the exhaust chambers 2b is 2, the partition wall 5a on the gas path is one, which is not sufficient for removing electrolytic droplets. Although the number of exhaust chambers 2b may be five or more, the number of exhaust chambers 2b is substantially appropriate because the structure is complicated.

  The adjacent exhaust chambers 2b communicate with each other through a gap 2c disposed between the partition wall 5a and the bottom wall 3. In the exhaust chamber 2b-1 that is closest to the electrolyte surface in the exhaust chamber 2b, that is, including the lowermost portion of the inclined bottom wall 3, the exhaust chamber 2b-1 and the exhaust gas are exhausted to the first exhaust cylinder 2. There is a first opening 2d that opens into the space on the battery side of the plug 1.

  On the other hand, a portion of the middle wall 4 corresponding to the exhaust chamber 2b-3 disposed at a position separating the at least one other exhaust chamber 2b-2 from the exhaust chamber 2b-1 in which the first opening 2d is formed. In addition, a second opening 2e and a third opening 2f penetrating the inner wall 4 are provided.

  The exhaust plug 1 of the present invention includes a porous filter 10 disposed so as to face the bottom surface 4a of the inner wall 4 in the battery outer side direction and cover the second opening 2e. Further, a second exhaust pipe 6 formed so as to protrude from the middle wall 4 around the third opening 2f in the battery outer side direction, that is, in the direction opposite to the protruding direction of the first exhaust pipe 2 is provided. Have.

  A cap-shaped valve body 7 is attached to the tip of the second exhaust cylinder 6, and the second exhaust cylinder 6 and the cap-shaped valve body 7 constitute a pressure release valve 8 that is opened when the battery internal pressure rises. . The pressure release valve 8 has an upper lid 9 for preventing the pressure release valve 8 from dropping from the second exhaust pipe 6. The upper lid 9 has a fourth opening 9a for discharging gas. As shown in FIG. 2, the upper lid 9 is configured to cover the upper surface of the porous filter 10 together with the cap-shaped valve body 7. However, these are provided individually, that is, the upper lid 9 and the porous cover covering the cap-shaped valve body 7. Another upper lid (not shown) that covers the upper surface of the quality filter 10 may be provided. At that time, an opening for discharging gas is provided in another upper cover that covers the upper surface of the porous filter 10.

  The gas exhaust path of the exhaust plug 1 of the present invention will be described. The gas containing the electrolyte droplet generated inside the battery enters the exhaust chamber 2b-1 through the first opening 2d that opens in the first exhaust cylinder 2. Thereafter, gas passes through the gap 2c and is introduced into the adjacent exhaust chamber 2b-2. At this time, since the gas flow collides with the partition wall 5a, a part of the electrolyte droplet is condensed on the surface of the partition wall 5a. The condensed electrolyte film grows with time, becomes electrolytic droplets, travels along the bottom wall 3 inclined from the partition wall 5a, is guided to the first opening 2d, and then from the first exhaust pipe 2. Drop and return to bulk electrolyte. The first opening 2d is formed so as to include the lowermost part of the exhaust chamber 2b-1 so that the electrolyte does not stay in the exhaust chamber 2b-1.

  The gas that has passed through the gap 2c and moved from the exhaust chamber 2b-1 to the exhaust chamber 2b-2 further moves to the exhaust chamber 2b-3 adjacent to the exhaust chamber 2b-2 via the gap 2c. At that time, the gas collides with the partition wall 5a between the exhaust chamber 2b-2 and the exhaust chamber 2b-3, and at that time, most of the electrolyte droplet remaining in the gas is condensed on the surface of the partition wall 5a. Thus, the electrolyte splash in the gas is removed.

  The electrolytic solution condensed on the surface of the partition wall 5a falls by gravity through the partition wall 5a, and travels from the gap 2c provided in the region including the lower portion of the partition wall 5a to the exhaust chamber 2b-1 through the bottom wall 3. It moves and falls to the electrolyte surface from the first opening 2d. It should be noted that the condensed electrolytic droplets do not stay in the exhaust chamber 2b-2 and the exhaust chamber 2b-3 but fall to the bulk electrolyte so that the lowermost portions of the exhaust chamber 2b-2 and the exhaust chamber 2b-3 The gap 2c is formed at the position including it.

  At the time of transition from the exhaust chamber 2b-2 to the exhaust chamber 2b-3, the gas in the exhaust chamber 2b-3 has most of the droplets of the electrolyte removed, but in the exhaust chamber 2b-3, the partition walls 5a and By coming into contact with the inner wall 2a, splashes of the electrolyte are further removed. Thereafter, the gas passes through the porous filter 10 through the second opening 2e, and is finally discharged out of the battery through the fourth opening 9a. A gap 4 b is disposed between the porous filter 10 and the inner wall 4. The surface of the intermediate wall 4 facing the gap 4b is unilaterally inclined downward toward the second opening 2e. Note that the second opening 2 e is disposed at a position close to the outer periphery of the porous filter 10.

  In the exhaust plug 1 of the present invention, most of the porous filter 10 is isolated from the exhaust chamber 2 b-3 by the inner wall 4. The porous filter 10 and the exhaust chamber 2b-3 communicate with each other through a second opening 2e whose opening area is limited to be smaller than the bottom area D of the porous filter 10. More preferably, the opening area S on the side facing the porous filter 10 of the second opening 2 e is limited to 20% or less of the bottom area D of the porous filter 10. According to such a configuration, most of the porous filter 10 does not directly face the second opening 2e. Therefore, even when a small amount of electrolytic droplets remain in the gas, the electrolytic droplets collide with a portion facing the second opening 2e of the porous filter 10, and the electrolytic droplets are formed at this portion. Condensation. The gas from which the electrolytic droplets have been removed diffuses in the gap 4b, and most of the gas passes through the porous filter 10 at portions other than the aforementioned portions and is released outside the battery.

  Therefore, the clogging of the porous filter 10 is intentionally caused to proceed on the surface facing the second opening 2e. Therefore, the clogging of the porous filter 10 as a whole is prevented because the clogging of the other portions hardly progresses. Clogging can be avoided.

  Note that the opening area S on the side facing the porous filter 10 of the second opening 2e is preferably limited to 20% or less of the bottom area D of the porous filter 10 as described above. If the ratio of D / S exceeds 20%, the progress of clogging of the porous filter 10 is made more uniform, which is not preferable because the life of the porous filter 10 is reduced.

On the other hand, the lower limit of the D / S ratio is determined by the relationship between the absolute value of the diameter of the second opening 2e and the ventilation rate. If the diameter of the second opening 2e is excessively small with respect to the gas generation speed during charging, the battery internal pressure increases, which is not preferable. Therefore, an opening area that does not cause an excessive increase in the battery internal pressure is ensured. There is a need. Examples of common starter lead storage battery per 50 Ah, may be secured to the opening area of 1.0mm ² ~2.0mm ^2.

  The exhaust plug 1 of the present invention further has a third opening 2f in the middle wall 4 and a second exhaust cylinder 6 provided corresponding to the third opening 2f and a cap-like valve body 7 attached thereto. When clogging of the porous filter 10 described above progresses and the battery internal pressure rises, the cap-shaped valve body 7 moves upward and is formed between the cap-shaped valve body 7 and the second exhaust cylinder 6. Gas is discharged through the gap, and the battery internal pressure rise is alleviated.

  In the present invention, the middle wall 4 protrudes from the bottom of the second exhaust pipe 6, and the opening area of the third opening 2 f is limited to be smaller than the area of the inner periphery of the second exhaust pipe 6. Therefore, even if a small amount of electrolytic droplets are present in the gas inside the exhaust chamber 2b-3, the inner wall 4 becomes a collision wall, and the diffusion of the electrolytic droplets into the second exhaust cylinder 6 is suppressed. Is done. Therefore, since the adhesion of electrolytic droplets to the cap-shaped valve body 7 and the second exhaust cylinder 6 is suppressed, the on-off valve pressure of the pressure release valve 8 is stabilized, and the clogging of the porous filter 10 proceeds. In addition, an excessive increase in the battery internal pressure that opens the valve at an appropriate battery internal pressure and causes deformation or breakage of the battery is suppressed.

  Note that the valve opening pressure of the pressure release valve 8 in the present invention is preferably set higher than the initial value of the pressure loss of the porous filter 10. According to such a configuration, in the initial state where the porous filter 10 is not clogged, the pressure release valve 8 is not opened, and thus gas discharge without passing through the porous filter 10 is suppressed. The pressure release valve 8 is opened when the clogging of the porous filter 10 has progressed and the battery internal pressure has increased to such an extent that unacceptable battery deformation or battery damage can occur.

(Second embodiment of the present invention)
FIG. 4 is a broken view showing a lead storage battery 11 according to the second embodiment of the present invention. The above-described exhaust plug 1 of the present invention is attached to the liquid port 12. ADVANTAGE OF THE INVENTION According to this invention, while having explosion-proof performance, even when the porous filter 10 is clogged, the malfunction by the internal pressure rise of a battery can be suppressed, and the lead storage battery excellent in reliability can be provided.

  Further, it is more preferable to apply the present invention to a lead storage battery in which either one of the positive electrode and the negative electrode lattice body is made of a lead alloy containing antimony. In the lead storage battery containing antimony in the lattice body, antimony eluted in the electrolytic solution easily causes clogging of the porous filter 10 together with the electrolytic droplets. In the present invention, even when antimony is included in the lattice, the clogging of the porous filter 10 is suppressed for a long time, and when clogged, the pressure release valve 8 operates to suppress problems due to an increase in battery internal pressure. .

  Hereinafter, the effects of the present invention will be described with reference to examples.

  The lead storage battery according to the present invention and the comparative example (80D26 type start lead storage battery in JIS D5301) was manufactured, and the degree of clogging of the porous filter 10 when charged in a high temperature environment while applying vibration to each lead storage battery and The degree of functional deterioration of the pressure release valve 8 was evaluated.

  The positive and negative bipolar plates were obtained by preparing lead-calcium alloy lattices and filling these lattices with an active material paste composed of lead powder, water, sulfuric acid, and the like.

  The separator used was a microporous membrane in which silica and mineral oil were added to polyethylene resin, and this was made into a bag shape to enclose the negative electrode plate.

The battery A of the present invention example is the exhaust plug 1 having the structure described in the first embodiment. As the porous filter 10, when air is flowed into the cell chamber at a flow rate of 500 cm ³ / min with the exhaust plug 1 attached to the battery A, the pressure inside the battery becomes +1 kPa with respect to atmospheric pressure, that is, A pressure loss of 1 kPa was prepared. The porous filter 10 is obtained by sintering polypropylene particles, and has a cylindrical shape with a diameter of 18 mm and a thickness of 5 mm.

In the cell of the battery A, the valve opening pressure of the pressure release valve 8 when air having a flow rate of 500 cm ³ / min is passed through the cell chamber is 20 kPa, which is higher than the pressure loss of the porous filter 10 described above. high. Further, when the inflow of air into the cell chamber is stopped, the battery internal pressure decreases with time, but when the battery internal pressure decreases to 5 kPa, the pressure release valve 8 is closed, and then the porous filter 10 is vented. Thus, the battery internal pressure is restored to atmospheric pressure. The cap-shaped valve body 7 is made of chloropyrene rubber whose inner diameter is 4% shorter than the outer diameter of the second exhaust cylinder 6.

  The battery B of the comparative example uses the exhaust plug 13 whose cross section is shown in FIG. 6, and has a configuration in which the inner wall 4 between the porous filter 10 and the exhaust chamber 2b-1 is removed. Further, the entire inner periphery of the second exhaust pipe 6 corresponds to the third opening 2f. Other configurations are the same as the battery A.

  In addition, the internal pressure which leads to the failure | damage of the battery case of each battery used by the present Example is 150 kP in a 20 degree environment. Generally, the internal pressure at the time of breakage of the battery case and lid of the lead storage battery is approximately 100 kPa to 200 kPa, although it varies depending on the battery size.

A vibration test was performed on the battery A of the present invention and the battery B of the comparative example. The vibration test was performed under the temperature atmosphere of 75 ° C., while the battery was continuously charged with a charging voltage of 13.8 V (maximum charging current 25 A) for 2000 hours, the battery was vibrated in the vertical direction with an acceleration of 2 G and a frequency of 15 to 33 Hz. For 1 hour. Thereafter, the ventilation resistance (pressure loss value at an air flow rate of 500 cm ³ / min) of the porous filter 10 of each battery, the valve opening pressure and the valve closing pressure of the pressure release valve 8 were measured. The results are shown in Table 1.

  In the battery A of the example of the present invention, the ventilation resistance of the porous filter 10 increased from the initial value, but in the battery B of the comparative example, measurement of the ventilation resistance was impossible due to clogging of the porous filter 10. . Further, in the battery A of the present invention example, both the valve opening pressure and the valve closing pressure of the pressure release valve 8 were slightly reduced. On the other hand, in the battery B of the comparative example, both the valve opening pressure and the valve closing pressure were 0 kPa, and the pressure release valve 8 was open regardless of the battery internal pressure.

  The clogging of the porous filter 10 of the battery B of the comparative example occurred 1800 hours after the start of charging, and the air permeability was completely lost due to the droplets of the fallen active material and the electrolytic solution containing the oil remaining in the separator. It was. Therefore, due to gas generation inside the battery, the pressure release valve 8 is always open during the charging time. Since the gas discharged from the pressure release valve 8 contains splashes of the electrolyte, the rubber deteriorates due to the oil, active material, or sulfuric acid contained in the splashes, and the function as the pressure release valve 8 is lost. It was.

  Obviously, if the pressure release valve 8 is always open, the gas is released outside the battery without passing through the porous filter 10 as a flame arrester, and may cause ignition.

  On the other hand, in the battery A of the present invention example, a slight increase in the ventilation resistance of the porous filter 10 and a slight decrease in the valve opening pressure and the valve closing pressure were observed, but the changes were compared with the battery B of the comparative example. Was insignificant and maintained almost the initial state.

  Next, when the battery A and the battery B described above were overcharged under the same vibration as described above using a positive electrode lattice body and a negative electrode lattice body containing 2.5% by mass of antimony, With respect to the battery A ′ corresponding to the battery A of the example of the present invention, the same result as that of the battery A shown in Table 2 was obtained. On the other hand, with respect to the battery B ′ corresponding to the battery B of the comparative example, the pressure release valve 8 was always opened due to clogging of the porous filter 10 after 750 hours of continuous charging.

  This also shows that the configuration of the present invention is particularly effective when the lattice contains antimony.

  An explosion-proof property test (explosion-proof property test defined in Section 8.3.15 of Battery Industry Association Standard SBA S1003) after each of the above vibration tests was performed for each charging current. In this test, a spark is forcibly generated on the exhaust hole (corresponding to the fourth opening 9a in FIGS. 2 and 5) of the exhaust plug 1 and the exhaust plug 13 while charging the battery, and the internal ignition to the battery is performed. It is to confirm the presence or absence of. The charging current started from 5A and increased every 5A if there was no ignition, and the maximum was 30A. The test was terminated when ignition occurred. The test results are shown in Table 2.

  From the results shown in Table 2, the battery A and the battery A ′ of the example of the present invention have the ventilation resistance (pressure loss) of the porous filter 10 lower than the valve opening pressure and the valve closing pressure of the pressure release valve 8, so The gas generated in is exhausted through the porous filter 10. Therefore, the drawing of fire into the battery can be blocked by the porous filter 10. On the other hand, the batteries B and B ′ of the comparative example lose their breathability due to clogging of the porous filter 10, so that the gas is discharged through the pressure release valve 8. As described above, since the airtightness of the pressure release valve 8 was impaired in the battery B and the battery B ′, the battery B and the battery B ′ ignited from the fire point outside the battery even inside the battery.

  As described above, as can be seen from the examples, according to the configuration of the example of the present invention, the clogging of the porous filter 10 is suppressed, and the pressure release valve arranged in parallel with the porous filter 10 is stabilized. Since it operates, there is a remarkable effect that it is possible to provide an exhaust plug for a lead storage battery excellent in reliability and a lead storage battery including the exhaust plug.

  INDUSTRIAL APPLICABILITY The present invention is suitable for a lead storage battery of a type having a free electrolytic solution inside the battery and mounting an exhaust plug on the liquid port.

DESCRIPTION OF SYMBOLS 1 Exhaust plug 1a Screw part 2 1st exhaust pipe 2a Inner wall 2b, 2b-1, 2b-2, 2b-3 Exhaust chamber 2c Gap 2d 1st opening part 2e 2nd opening part 2f 3rd opening part 3 Bottom wall 4 Middle wall 4a Bottom surface 4b Gap 5 Axis 5a Partition wall 6 Second exhaust cylinder 7 Cap-shaped valve body 8 Pressure release valve 9 Upper lid 9a Fourth opening 10 Porous filter 11 Lead storage battery 12 Liquid port 13 Exhaust plug

Claims (5)

An exhaust plug for a lead storage battery that is attached to the liquid port of the lead storage battery and has an exhaust structure inside,
The exhaust plug is
A first exhaust pipe that hangs down toward the electrolyte surface in a state of being attached to the liquid port;
A bottom wall disposed at one end of the first exhaust stack in the battery inner direction;
An inner wall disposed at one end of the first exhaust stack in the battery outer direction;
An axis depending from the central region of the middle wall toward the bottom wall;
N partition walls arranged radially from the shaft toward the inner wall of the first exhaust pipe and dividing the inside of the first exhaust pipe into at least n (n ≧ 4) exhaust chambers;
The bottom wall has an inclination angle θ (0 ° <θ <90 °) with respect to the electrolyte surface,
The adjacent exhaust chambers communicate with each other via a gap disposed between the partition wall and the bottom wall,
The first exhaust tube corresponding to the exhaust chamber closest to the electrolyte surface among the plurality of exhaust chambers has a first opening;
A second opening that penetrates the middle wall in a portion corresponding to the exhaust chamber disposed at a position separating at least one other exhaust chamber from the exhaust chamber corresponding to the first opening of the middle wall. And a third opening,
A porous filter arranged to face the bottom surface of the inner wall in the battery outer side direction and cover the second opening;
A second exhaust pipe that communicates with the third opening and is formed to protrude from the inner wall toward the battery outer side;
A pressure release valve comprising a cap-like valve body mounted on the second exhaust pipe;
The opening area S on the side facing the porous filter of the second opening is limited to less than the bottom area D of the porous filter,
The opening area of the third opening 2f is limited to be smaller than the inner peripheral area of the second exhaust pipe 6,
An exhaust plug for a lead storage battery comprising an upper lid having a large number of the cap-shaped valve body and the porous filter and having a fourth opening for discharging gas. The exhaust plug for a lead storage battery according to claim 1, wherein the valve opening pressure of the pressure release valve is set higher than the initial value of the pressure loss of the porous filter. 3. The lead-acid battery exhaust plug according to claim 1, wherein the opening area S is limited to 20% or less of the bottom area D. 4. A lead acid battery comprising the exhaust plug for the lead acid battery according to claim 1, 2 or 3. The lead acid battery according to claim 4, wherein either one of the positive electrode and the negative electrode lattice body is made of a lead alloy containing antimony.

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