JP2005276741A - Lead storage battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a maintenance free lead storage battery, especially used as the battery for starting, having simple structure, restrained from a decrease of electrolytic solution. <P>SOLUTION: The lead storage battery, using Pb-Ca group alloy for the latticed body of a cathode and an anode, has an exhaust plug mounted on a liquid port formed on the case of the battery, a sheet covering an exhaust port of an exhaust plug, and a gas exhaust passage formed on the sheet or the part between the sheet and the case, guiding the exhaust gas exhausted from the exhaust port to a part distant from the exhaust port. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lead-acid battery.

  Lead-acid batteries are used for various purposes such as vehicle engine starting and backup power supply. Among them, the start lead-acid battery supplies power to various electric and electronic devices mounted on the vehicle as well as power to the engine start cell motor. After the engine is started, the battery is charged by the alternator. Here, the output voltage and output current of the alternator are set so that charging and discharging of the battery are balanced and the SOC (charged state) of the battery is maintained at almost 100%. Such a lead acid battery for starting is different from a lead acid battery for cycle service, and is used at a relatively high SOC.

  In most cases, the starting lead-acid battery is installed in the engine room. Therefore, the operating temperature of the lead storage battery is frequently 40 ° C. or higher, and more often 80 ° C. On the other hand, as described above, the lead acid battery for start-up (hereinafter referred to as “storage battery”) is continuously or intermittently charged by the alternator during vehicle operation, and thus is frequently overcharged in a high temperature atmosphere.

  When the storage battery is overcharged, the water in the electrolytic solution is decomposed into oxygen gas and hydrogen gas and discharged outside the battery, so that the water in the electrolytic solution is reduced. As a result, the concentration of dilute sulfuric acid in the electrolytic solution increases, and the capacity decreases due to corrosion deterioration of the positive electrode plate. In addition, when the electrolytic solution surface is lowered and the electrode plate is exposed from the electrolytic solution, problems such as a rapid decrease in discharge capacity and corrosion of the connection between the negative electrode plate and the terminal occur.

  As described above, particularly in a starting storage battery, suppression of moisture reduction (hereinafter referred to as “liquid reduction”) in the electrolyte is a serious problem. For the purpose of suppressing the liquid reduction of the storage battery, a storage battery using a Pb—Ca alloy has been put into practical use for both the positive grid and the negative grid.

  On the other hand, there are two causes of the storage battery depletion: gas generation due to water electrolysis as described above, and one that occurs when the water in the electrolyte simply evaporates and this water vapor is released outside the storage battery. . By using the Pb—Ca alloy for the positive electrode / negative electrode lattice, the former liquid reduction due to electrolysis of water can be suppressed, but the liquid reduction due to water evaporation is not particularly effective.

  It is known that such liquid reduction due to water evaporation can be suppressed to some extent by taking an appropriate method for preventing water vapor from escaping outside the storage battery. For example, in Patent Document 1, a filter that suppresses the permeation of water vapor is disposed in the liquid stopper of the storage battery, or as shown in Patent Document 2, the gas discharge path provided in the storage battery lid has a maze structure, and the water vapor is discharged. A method is known in which dew condensation occurs while passing through a route, and this dew condensation water is returned to the storage battery.

  In the former filter arrangement, it is effective to reduce the pore size of the filter in order to obtain the effect of suppressing water vapor permeation. However, the moisture condensed in the filter clogs the pores of the filter, thereby causing clogging and causing a problem that the internal pressure of the storage battery is abnormally increased. On the other hand, when the pore size of the filter was made larger, the occurrence of clogging could be suppressed, but a sufficient moisture evaporation suppression effect could not be obtained.

Further, in the case where the latter gas discharge path has a labyrinth structure, the labyrinth structure needs to be disposed in the upper part of the battery case, and the size of the storage battery must be increased. Normally, the external dimensions of the lead acid battery for starting are standardized, so when providing the maze structure with the same model, it is necessary to lower the height of the battery case, resulting in a decrease in the amount of electrolyte, Measures such as reducing the electrode plate size are required. All of these measures are undesirable in terms of the capacity and life of the storage battery.
Japanese Patent Laid-Open No. 7-220707 JP-A-8-22815

  The present invention is to provide a storage battery that is easy to suppress the amount of liquid reduction and has excellent maintenance-free performance by suppressing moisture evaporation from the electrolyte inside the storage battery as described above.

  In order to solve the above-described problem, the invention according to claim 1 of the present invention is a lead storage battery using a Pb—Ca-based alloy for the positive electrode grid body and the negative electrode grid body, and is provided on the exterior of the lead storage battery. A gas having an exhaust plug attached to the liquid port, a sheet covering the exhaust port of the exhaust plug, and guiding the exhaust gas from the exhaust port to a discharge position spaced from the exhaust port between the sheet or the sheet and the exterior The lead storage battery characterized by providing the discharge path is shown.

  Furthermore, the invention according to claim 2 of the present invention is the lead storage battery of claim 1, wherein the sheet is bonded to the exterior via a bonding layer made of an adhesive or a pressure-sensitive adhesive, The lead storage battery is characterized in that a non-joining portion having no joining layer is provided on the surface of the sheet facing the exterior from the periphery of the exhaust port to the discharge position.

  And the invention which concerns on Claim 3 of this invention is a lead acid battery of Claim 1 or Claim 2, WHEREIN: The porous filter was arrange | positioned on the gas exhaust path from the said exterior to the said exhaust port, It is characterized by the above-mentioned. It shows a lead storage battery.

  According to the configuration of the present invention described above, liquid reduction due to moisture evaporation inside the lead storage battery can be remarkably suppressed. And with this liquid reduction suppression effect, since the structure of this invention can be obtained comparatively simply, it is very useful industrially.

  Embodiments of the present invention will be described below. FIG. 1 shows an outline of an example of the lead storage battery of the present invention.

  The lead acid battery 1 according to the present invention has a positive grid (not shown) and a negative grid (not shown) made of a Pb—Ca alloy. These lattice bodies are filled with an active material, and a positive electrode plate 2 and a negative electrode plate 3 are formed, respectively. The positive electrode plate 2 and the negative electrode plate 3 and the separator 4 are combined, and the current collecting ear portions 5 and 5 ′ of the same polarity electrode plate are joined to form an electrode plate group. The required number of these electrode plate groups is housed in the battery case 6 that is a part of the battery case, and the lid 7 that is also a part of the battery case covers the opening of the battery case 6.

  The lid 7 serving as the battery exterior is provided with a liquid injection port 8 for injecting an electrolyte into the battery, and an exhaust plug 9 is attached to the liquid injection port 8. The exhaust plug 9 is provided with an exhaust port 10 for discharging gas inside the battery to the outside of the battery.

  The lead storage battery 1 of the present invention includes a sheet 11 that covers the exhaust port 10 of the exhaust plug 9. As shown in FIG. 2, a gas discharge path 12 is provided between the sheet 11 and the lid 7. The gas discharge path 12 is provided over a gas discharge position 13 provided at a position separated from the exhaust port 10. The gas discharged from the exhaust port is finally discharged out of the battery via the gas discharge path 12 at the gas discharge position 13.

  The structure of the gas discharge path 12 is shown in FIG. A sheet 11 covering the exhaust port 10 is bonded to a lid 7 as a storage battery exterior by a bonding layer 14 made of an adhesive or an adhesive. And the part which opposes the exhaust port 10 circumference | surroundings of the sheet | seat 11 has the non-joining part 15 which does not provide the joining layer 14. FIG. As shown in FIG. 2, the non-joint portion 15 is provided with the gas discharged from the exhaust port 10 over the discharge position 13. As a result, the gas is finally discharged out of the battery at the discharge position 13 via the non-joint portion 15. With such a configuration, a gas discharge path can be formed on the surface facing the lid 7 as the exterior of the sheet 11.

  Although FIG. 2 shows an example in which the non-joining portion 15 is formed in a strip shape, the non-joining portion 15 can also be formed as shown in FIG. As shown in FIG. 4, a discharge port 16 may be provided at a position away from the exhaust port 10 of the sheet 11, and this discharge port may be used as the discharge position 13. In addition, as long as the discharge path 12 can be secured, the non-joint portion 15 may be formed in any pattern.

  Here, considering the contact with the electrolyte as the sheet, a sheet having a certain degree of acid resistance is preferable. For example, a PET resin sheet or synthetic paper can be used. Further, a thin sheet having a thickness of 0.2 to 0.05 mm can be used.

  As an example of the adhesive or pressure-sensitive adhesive used as the bonding layer 14, it can be appropriately selected according to the required affixing strength, but an acrylic solvent type can be used as an example. Moreover, what is necessary is just to set the layer thickness by several micrometers-several hundred micrometers, for example. By applying the bonding layer 14 to the sheet 11 in advance, the sheet 11 can be smoothly arranged on the lid 7 in the process.

  It is also possible to apply the adhesive to the lid 7, place the bonding layer 14 in advance, and place the sheet 11 on the bonding layer 14. Of course, it is also possible to print on the sheet 11 a sentence describing the storage battery product number and precautions for handling, so that the sheet 11 has a function as a label.

  According to such a configuration of the present invention, the gas discharge path 12 formed by the non-joint portion 15 becomes a space having a water vapor pressure equivalent to that inside the storage battery due to the water vapor discharged from the exhaust port. Further, the opening height at the discharge position 13 which is the end of the gas discharge path 12 is about the thickness of the bonding layer 14, and the gas discharge is caused by the flow of airflow outside the battery from the discharge position 13 into the gas discharge path 12. The frequency at which the water vapor pressure in the passage 12 space is affected by the external airflow is extremely low.

  Thereby, the water vapor pressure in the space of the gas discharge path 12 is maintained substantially equal to the inside of the battery. Therefore, the space between the inside of the battery and the gas discharge path is close to an equilibrium state in water vapor diffusion, and the release of water vapor from the battery is suppressed. Even if the water vapor pressure in the gas discharge path decreases, the exhaust port 10 is covered with the sheet 11 through the narrow gap of the bonding layer 14, and the sheet 11 Because it is arranged to impinge on the flow, water vapor is not easily released from within the battery. As a result, the decrease of the electrolyte due to the discharge of water vapor from the inside of the storage battery is suppressed.

  Furthermore, as a preferred embodiment of the present invention, as shown in FIG. 3, by disposing a porous filter 17 on the gas discharge path from the inside of the battery to the exhaust port 10 provided in the exhaust plug 9, the liquid reduction amount Can be suppressed synergistically.

  The configuration of the present invention as described above does not have a complicated structure as shown in Patent Document 2, and can be manufactured relatively easily without any modification to the conventional battery case lid. It is. Further, a space like the structure for refluxing the electrolytic solution disclosed in Patent Document 2 is not necessary, and it is effective in that the electrode plate dimensions can be secured accordingly.

  The effects of the present invention will be described below with reference to examples.

  In the battery of the present invention example in which the gas discharge passages 12 shown in FIG. 2 are arranged in a band shape, the battery (battery A of the present invention example) provided with the porous filter 17 as shown in FIG. A battery not provided (battery B of the present invention example) was prepared. The battery type was a 55D23 battery specified in JIS D5301.

  In addition, in the conventional battery not having the sheet 11 in FIG. 2, a battery having a porous filter in the exhaust plug (battery C of the conventional example) and a battery not provided with this porous filter (battery D of the conventional example) )created.

  Each of these test batteries was measured for the amount of liquid reduction by a test under the following conditions.

Test conditions:
1) Test temperature: 40 ° C in gas phase atmosphere 2) Test battery is overcharged for 14.8V constant voltage for 20 days 3) During constant voltage overcharge of 2), the test battery is vibrated up and down at an acceleration of 1G and 30Hz State.

  4) During the constant voltage overcharge of 2), an air flow with a wind speed of 1.0 m / sec is continuously flowed horizontally on the upper surface of the test battery.

  5) Measure the battery weight loss before and after the constant voltage overcharge in 1), and use this as the liquid reduction amount.

  In the above test, the test battery is vibrated in the vertical direction to simulate vibrations in the vehicle running state, thereby intentionally generating electrolyte surface fluctuations, thereby replacing the gas in the battery and water vapor. The dissipation of water was promoted, that is, the conditions were severe for liquid reduction. Further, the horizontal airflow on the upper surface of the battery is intended to simulate a radiator fan generated around the battery in the engine operating state and a traveling wind that is taken into the engine room from the outside of the vehicle as the vehicle travels.

  The results of measuring the amount of liquid reduction by the above test method are shown in Table 1 as an index with the amount of liquid reduction in the battery D of the conventional example taken as 100.

  From the results shown in Table 1, it can be seen that the battery A and the battery B of the present invention can greatly reduce the amount of liquid reduction compared to the batteries C and D of the conventional example. The effect of the present invention is that the exhaust port 10 of the exhaust plug 9 is disposed so as to be covered with the sheet 11, so that the gas discharge path 12 between the exhaust port 10 and the sheet 11 is a narrow space, and the water vapor pressure of this space is set inside the battery. In addition, the gas discharge path 12 communicates with the outside of the battery only through a slight gap corresponding to the bonding layer 14, and as a result, the water vapor pressure in the gas discharge path 12 is influenced by the external airflow. It is thought that it was obtained because it was able to maintain almost the same as the inside of the battery.

  Further, when compared with the presence or absence of a porous filter, the liquid reduction suppression effect by the porous filter in the present invention example is more remarkable than that in the conventional example, and by using this porous filter, the liquid reduction suppression effect is synergistic. It can be seen that can be obtained. Although the mechanism of this synergistic effect is not clear, it can be assumed that the time required for the gas exhaust path 12 and the water vapor pressure in the battery to reach an equilibrium state is longer due to the ventilation resistance of the porous filter.

  Since the present invention remarkably suppresses the liquid reduction in the lead storage battery, it is extremely effective as a maintenance-free type lead storage battery for starting.

Cross-sectional view showing a lead storage battery of the present invention The top view which shows the lead acid battery of this invention The figure which shows the principal part of the lead acid battery of this invention The figure which shows the other lead acid battery of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lead acid battery 2 Positive electrode plate 3 Negative electrode plate 4 Separator 5,5 'Current collection ear 6 Battery case 7 Lid 8 Injection port 9 Exhaust plug
DESCRIPTION OF SYMBOLS 10 Exhaust port 11 Sheet | seat 12 Gas discharge path 13 Discharge position 14 Joining layer 15 Non-joining part 16 Exhaust port 17 Porous filter

Claims (3)

A lead-acid battery using a Pb—Ca-based alloy for a positive electrode grid and a negative-electrode grid, and includes an exhaust plug mounted on a liquid port provided on the exterior of the lead storage battery, and covering the exhaust port of the exhaust plug A lead storage battery comprising a gas discharge path for guiding exhaust gas from the exhaust port to a discharge position spaced from the exhaust port between the sheet or the sheet and the exterior. The sheet is bonded to the exterior via a bonding layer made of an adhesive or a pressure-sensitive adhesive, and is bonded as a gas discharge path from the periphery of the exhaust port to the discharge position on the surface facing the exterior of the sheet. The lead-acid battery according to claim 1, wherein a non-joining portion having no layer is provided. The lead acid battery according to claim 1 or 2, wherein a porous filter is disposed on a gas discharge path from the interior of the exterior to the exhaust port.

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