JP2009231180A - Lead-acid battery - Google Patents

Abstract

In a lead-acid battery having a liquid spout, each part constituting the liquid spigot is prepared in advance, and then the parts are assembled, resulting in high costs and a porous body disposed in the liquid spigot. Even if it did, the problem of the fall of the gas discharge | release function resulting from clogging etc. by the exhaust hole which exists in the upper part, and the liquid leakage in actual use remained.
In a lead-acid battery in which a liquid spigot is provided on a lid, the liquid spigot is formed of a porous body made of a thermoplastic resin, thereby having a wide surface area for exhausting gas generated in a cell chamber. It is released through the porous body to suppress clogging and liquid leakage characteristics during actual use.
[Selection] Figure 2

Description

  The present invention relates to a lead-acid battery.

  Lead acid batteries are widely used as inexpensive and stable secondary batteries. Lead-acid batteries for start-up installed in many automobiles have a positive electrode plate and negative electrode plate immersed in a free electrolyte, and a liquid stopper is attached to the liquid port provided on the lid that connects the inside and outside of the battery. Is done.

  The lead acid battery in which this free electrolyte solution exists needs to efficiently release oxygen and hydrogen gas generated by electrolysis of the electrolyte solution during charging to the outside of the cell chamber. If the generated gas cannot be discharged to the outside, the internal pressure of the cell chamber increases, and eventually the battery may burst. A general liquid spout is provided with an exhaust hole for gas discharge, and the pressure inside the cell chamber is kept stable by discharging the generated gas to the outside of the cell chamber and introducing the atmosphere.

  On the other hand, if the generated gas is discharged from the exhaust hole and the conditions for generating sparks in the vicinity of the liquid stopper overlap, the gas inside the cell chamber may be ignited through the exhaust hole. In general, the main body of the liquid lead plug of the lead-acid battery for start-up is composed of a combination of synthetic resin parts. However, in order to avoid the above-mentioned ignition, the porous body (filter) is exhausted inside the liquid spout. There are many methods that are arranged in the middle of the route to suppress external ignition.

  The porous body is prepared in advance as an in-mold sintered molded product using a thermoplastic resin powder, and is mounted in an exhaust passage existing inside the liquid spout exterior part. A gas exhaust hole in the plug body is provided separately. As the vehicle travels, mud and dust accumulate in this exhaust hole and the space between the exhaust hole and the porous body and solidify by drying, resulting in clogging in the exhaust hole part, increasing the internal pressure of the cell and contributing to battery rupture. It was.

  On the other hand, the electrolyte may leak from the exhaust hole of the liquid port plug due to vehicle vibration, etc., but the leakage control can be suppressed by placing a splash-proof body inside the liquid port plug that returns the splash component of the electrolyte to the cell chamber. The structure is taken. The splash-proof body is composed of a horizontal plate in which the interior of the liquid stopper is divided into a plurality of stages by a splash-proof plate and a vertical plate that supports the plate. It has a structure to do. Furthermore, during overcharge due to vehicle vibration with a very large amplitude or a very large current, even if the inside of the liquid spigot has a complex splash-proof structure and a porous body is present, electrolyte droplets and gas components are separated. There was no separation, and electrolyte leakage occurred from the exhaust hole of the liquid stopper.

  Further, in order to attach and fix the liquid spigot to the lid of the storage battery, a screw portion at the lower part of the liquid spigot, which is previously provided with a rubber packing for fastening and fixing, is screwed into the lid. As described above, since a general liquid spout is assembled by a plurality of parts, the number of man-hours for assembling each part is required in addition to the cost of the material of the part itself, and the ratio of the man-hour to the part cost cannot be ignored.

  For these configurations, as shown in Patent Document 1 and Patent Document 2, the contents of cost reduction are shown by the simplified configuration.

  Patent Document 1 proposes a configuration in which a porous sheet is attached to an upper surface of an exhaust port where a lid of a storage battery exists without mounting a liquid port plug part or the like.

  However, this method is excellent in cost, but it is assumed that the porous sheet and the lid are joined by an adhesive, ultrasonic welding, or the like. For this reason, in extremely thin porous sheets, strength against tearing, gas ventilation resistance, airtight and liquid-tight reliability due to adhesives or ultrasonic welding, etc., anti-leakage property due to vibration leak resistance test during overcharge and It has been difficult to satisfy each quality item that should be considered in the current market usage, such as storage battery swelling caused by setting the ventilation resistance high.

  In Patent Document 2, the tube tip of the liquid spout main body has an inclined structure, and a gas permeable membrane is attached to the inclined tip of the tube. This is a configuration that does not require a separate splash-proof structure that can be selectively discharged to the outside of the cell chamber.

However, there is no mention about the attachment of the porous body inside the liquid stopper, and it cannot be said that the gas permeability when used for a long period of time and the measures against leakage from the liquid stopper are sufficient. If an expensive member of the permeable membrane must be prepared as a separate part, this must be attached to the liquid stopper in a separate process, and the porous body must be attached as before, from a cost standpoint. Practical application was difficult.
Japanese Utility Model Publication No. 61-60462 JP 11-345605 A

  In the lead-acid battery having the liquid plug as described above, the liquid plug becomes expensive by assembling the parts prepared in advance, and the porous body that prevents external ignition and leakage is used as the liquid plug. Even if it is arranged inside, there is still a problem that the release of the generated gas is hindered due to clogging of the exhaust hole in the upper part and that the electrolyte leaks during actual use. .

  In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention is a lead-acid battery in which a liquid stopper is provided on a lid, wherein the liquid stopper is formed of a porous body molded of a thermoplastic resin. The lead acid battery is shown.

  The invention according to claim 2 of the present invention shows the lead-acid battery according to claim 1, wherein the surface of the porous body of the liquid spout has a portion that does not have air permeability.

  The invention according to claim 3 of the present invention shows the lead storage battery according to claim 1 in which a splash-proof component is mounted inside the liquid spout.

  The invention according to claim 4 of the present invention is the lead storage battery according to claim 1, wherein the ventilation resistance value of the liquid plug is a pressure in the cell chamber of 1.0 kPa to 20 kPa when the gas flow rate is 5 l / min. It is.

  According to the present invention, the liquid plug of the lead storage battery provided with a liquid plug on the lid has a form in which a porous body having a function as an explosion-proof filter is mounted inside the liquid plug in a normal use. In addition to reducing the number of splash-proof body parts and controlling the ventilation resistance of the porous body, it is possible to efficiently recirculate electrolyte droplets and selectively release gas components. Furthermore, a problem such as clogging of the porous body does not occur, and it is possible to obtain a remarkable effect that it is possible to provide a lead storage battery including a liquid port plug having low cost and excellent reliability.

  Embodiments of the present invention will be described below.

(First embodiment)
FIG. 1 is a view showing an appearance of a lead storage battery according to an embodiment of the present invention. The liquid spigot 1 according to the present invention is attached to the upper part of the lid 2, and there is no difference in appearance from the state in which the conventional liquid spigot is attached. FIG. 2 shows a cross-sectional view of the liquid stopper in the AA ′ cross section in FIG. 1 in the detailed description of the present invention.

  The liquid spigot 1 of the present invention shown in FIGS. 1 and 2 is made of a material mainly composed of polypropylene resin and polyethylene resin. The liquid spigot 1 is provided with a screw part 3 for attaching to the lid 2 at the lower part, and a rubber packing 4 for attaching and fixing to the lid securely attached to the screw part 3. A groove portion 5 used for tightening when the stopper 1 is screwed onto the lid 2 is provided on the surface of the liquid stopper.

  The porous body forming the liquid spigot 1 uses particles having a diameter of about 0.5 mm in the polypropylene resin and polyethylene resin, is filled in a mold having the shape of a liquid spigot, and is sintered at a temperature of 160 ° C. Can be molded.

  As another construction method for creating a porous body, it can be created in the same manner as ordinary resin material injection molding, and it has open cells by injection molding by adding an additive that becomes a foam material to the resin material. A porous body can be formed. The selection of the construction method should be selected from the viewpoint of production quantity, mold cost and raw materials, and the conditions can be appropriately set according to the storage battery used in terms of air permeability and physical strength.

  The liquid spigot 1 produced as described above has gas permeability from the entire surface because the entire surface of the liquid spigot has air permeability due to its porous characteristics. With this configuration, the gas generated in the cell can be released using not only the conventional exhaust holes having a small gas release area but also the entire porous body exposed on the surface of the lid 2. .

(Second Embodiment)
FIG. 3 is a cross-sectional view of the liquid spigot according to the second embodiment of the present invention in the AA ′ cross section in FIG. 1, and the liquid spigot 1 made of a porous material is the same as that of the first embodiment. Although it is a liquid stopper structure, it exists in specifying the site | part which can let gas pass through the surface of the liquid stopper 1 of a porous body. The liquid spigot 1 is configured by specifying a range through which the gas is released into the atmosphere as a gas passing surface range 6 and a range through which the gas in the cell chamber passes through the porous body as a gas passing back surface range 7.

  Here, the gas passage surface range 6 exists in a circular shape in the upper surface central portion 8 of the liquid stopper 1, and the gas passage rear surface range 7 exists on the bottom portion 9, the inner side surface 10, and the back side top surface 11 of the liquid stopper. By setting the gas to pass therethrough, the gas passes through the inside of the porous body and passes through the surface center portion 8 to be released. A portion corresponding to the surface edge portion 13, the outer side surface 14, and the screw portion 3 of the liquid spigot 1 has a skin layer 12 partially formed on the surface of the porous body that does not require a gas passage function. Make the configuration without function.

  The skin layer 12 that identifies a portion that does not have a gas passage function is a region other than the gas-passable range (the gas passage surface range 6 and the gas passage back surface range 7) when the porous body of the liquid spigot 1 is molded. It can be obtained by crushing the pores of the porous body existing on the surface by melting the porous surface by setting the resin temperature of the surface portion to 220 ° C.

  As another method for obtaining the skin layer 12, the temperature of the mold is set high, and a skin layer having no air permeability is formed on the entire surface of the liquid spout 1 of the porous body during injection molding. There is also a method of providing a gas passage range by partially removing the skin layer later by machining.

  As described above, it is also possible to limit the portion through which gas passes to the surface, and this design requirement is based on the physical property requirements on the surface of the porous body, the gas exhaust capacity required for the storage battery, and the interior of the cell It is set according to the request for the upper limit set value of the pressure.

  As described in the first and second embodiments, the liquid spout itself is formed of a porous body, and the surface area for releasing the gas can be widened, so there is no need to prepare explosion-proof filter parts. Both have the function of suppressing external ignition.

  Furthermore, since the liquid spout of the present invention does not need to be provided with a separate gas exhaust hole, it is not necessary to mount a splash-proof plate structure component for preventing the electrolyte droplet from leaking from the gas exhaust hole. As described above, according to the embodiment of the present invention, various parts can be reduced, and the assembly cost can be reduced.

(Third embodiment)
However, in consideration of the condition in which a vehicle with a lead-acid battery is subjected to greater vibrations and the case where overcharging occurs at the same time, the porosity of the porous body is lowered to suppress leakage while maintaining the air permeability. There is a need. This can be dealt with to some extent by controlling the molding conditions, the size of the raw material powder, the amount of the foaming additive, the foaming conditions, and the like. However, there is a phenomenon in which gas release is hindered by lowering the porosity, and the electrolytic solution component adhering to the pressure increase in the cell passes through the porous body.

  FIG. 4 is a cross-sectional view of a liquid spigot according to a third embodiment of the present invention, in which a structure capable of mounting the splash-proof plate structural component 15 is provided inside the main body of the liquid spigot 1 made of a porous body. If necessary, the splash-proof plate structural component 15 is selectively mounted so as not to leak.

  A gas exhausting / refluxing slit 16 is provided at the bottom of the porous liquid spout 1 and has a function of returning the liquid recirculated by the splash-proof plate structural component 15 into the cell chamber. Further, since it is necessary to surely introduce the released gas from the gas exhaust / reflux slit 16, the skin layer 12 is provided on the surface of the slit portion of the corresponding liquid spout 1.

  With this configuration, the generated electrolyte splashes reduce the amount of the porous material that reaches the back side of the porous body. By providing the plug 1 inside, it is possible to obtain a larger effect of suppressing leakage and to maintain air permeability without lowering the porosity.

  The optimum characteristic evaluation test in the present invention was carried out using 80D26 defined in JIS D5301 “lead battery for starting” as a test battery. In the evaluation test, the porous liquid port plug described in the second embodiment was used, and the diameter of the gas passage surface range 6 of the upper surface central portion 8 of the liquid port plug 1 was set to 14 mm. The porous body is prepared by introducing a mixed powder of polypropylene resin and polyethylene resin into a mold and sintering, and the airflow resistance is 0.8 kPa, 1 depending on the powder size and mixing ratio of these resin materials. Six types of 0.0 kPa, 5.0 kPa, 10.0 kPa, 20.0 kPa, and 25.0 kPa were formed as sample products. For comparison, a liquid spigot in which a porous body is mounted inside a liquid spigot described in Patent Document 2 as a general liquid spout plug component, and a gas permeable membrane shown in Patent Document 1 Two types with large and small ventilation resistance were selected and evaluated for each type.

  As the first evaluation item, the ventilation resistance of each sample was measured. The measurement method is that air is forced to flow at a flow rate of 5 l / min from an air inlet port that has been pre-processed into a cell constituting the lead storage battery after being attached to the lead storage battery. The pressure value inside the cell chamber when being released more was measured.

  The second evaluation item is to install a lead-acid battery with each sample product individually attached to a taxi that will be accelerated in terms of mileage in order to check durability in a general usage environment by mounting it on an actual vehicle. Two units were installed, and a running test of about 60,000 km was carried out at a running distance for 6 months to check for leakage and other abnormal phenomena.

  The third evaluation item was to check the gas leakage resistance performance by generating a charging condition and running vibration, assuming gas exhaust under bad conditions that could occur in the market. As charging conditions at this time, the current value 60A, which is assumed to occur at the maximum when the regulator fails, was overcharged by a constant current, and was vibrated for 2 hours under the vibration conditions defined in JIS D5301 "Leading start battery". Since the storage battery at the end of this test could be a defect in appearance, the swelling in the long side direction was also measured.

  As a fourth evaluation item, a spark was generated at a position 50 mm above the liquid stopper when each sample product was charged, and the explosion-proof performance by external ignition was evaluated.

  These evaluation results are summarized in Table 1.

  In contrast to the results shown in Table 1, the liquid mouth plugs of the current general products were satisfactory for all evaluation items. However, as described above, the cost increases because a plurality of parts constitute the liquid spigot.

  On the other hand, the two types of prototypes based on Patent Document 1 have different tendencies depending on the type of gas permeable membrane. The parts used for A were low ventilation resistance and high porosity among porous membranes, but liquid leakage was observed in the combined test of overcharge and vibration, and the explosion-proof test results could maintain the explosion-proof function. There wasn't. The part used for B uses a membrane with a very high ventilation resistance and a low porosity, but because of the use of a film with a high porosity, there is no problem seen with the A part, but the storage battery is affected by the effect of the ventilation resistance. It became clear that the swelling of was large. From the above results, it can be seen that it is difficult for the configuration of Patent Document 1 to design a balance between the characteristics of the storage battery based on the gas film selection and the required performance.

  In contrast to these results, only the test battery having a ventilation resistance of 0.8 kPa in the liquid stopper of the present invention resulted in unfavorable results in two items, a test combining overcharge and vibration, and an explosion-proof test. In the test batteries other than the above, all the test batteries having a ventilation resistance of 1.0 kPa or more had no problem with respect to basic physical properties. However, the test batteries with a ventilation resistance of up to 20.0 kPa were not significantly swollen at 10 mm or less, but when the ventilation resistance was 25.0 kPa, a significant swelling reaching 23 mm at the maximum was observed. Therefore, when considering from the allowable range of appearance defects in the general market, the practical range is up to 20.0 kPa.

  From the above results, in the embodiment of Patent Document 1, when adverse conditions in the market overlap, there are many problems in design adjustment for the practical application of the corresponding liquid spout, so these must be dealt with. When the porous material is attached to Document 2, the cost increases, but with the liquid spout according to the present invention, the ventilation resistance of the porous material can be set widely in production and practical use, and it is widely used in the market. A lead storage battery that can withstand the conditions can be provided.

  As described above, according to the present invention, the liquid spout main body does not require a separate part and does not require an exhaust hole, can reduce the assembly of a plurality of parts, and can maintain leakage resistance and explosion-proof performance. Because it is possible, its industrial value is high.

External view of the lead storage battery of the present invention Sectional view of the liquid spigot of the present invention (AA ′ sectional view of FIG. 1) Cross-sectional view of a liquid spigot according to a second embodiment of the present invention A cross-sectional view of the liquid spigot of the third embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid stopper 2 Cover 3 Screw part 4 Rubber packing 5 Groove part 6 Gas passage surface range 7 Gas passage back surface range 8 Upper surface center part 9 Bottom part 10 Inner side surface 11 Back side top surface 12 Skin layer 13 Surface edge part 14 Outer side surface 15 Prevention Splash plate structural parts 16 Gas exhaust and reflux slit

Claims (4)

A lead acid battery in which a lid is provided with a liquid stopper, wherein the liquid stopper is formed of a porous body molded of a thermoplastic resin. The lead acid battery according to claim 1, wherein a portion having no air permeability exists on a surface of the porous body of the liquid stopper. The lead-acid battery according to claim 1, wherein a splash-proof component is mounted inside the liquid spout. The lead storage battery according to claim 1, wherein the ventilation resistance value of the liquid plug is a pressure in the cell chamber of 1.0 kPa to 20 kPa when the gas flow rate is 5 l / min.

Images