JP2012015006A - Lead storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly safe lead storage battery that does not cause failure inside a vehicle room even under unexpected on-vehicle conditions.SOLUTION: A lead storage battery includes: a battery case with an inside partitioned into a plurality of cell chambers, each cell chamber being provided with a valve body for discharging gas when an internal pressure becomes a predetermined value or larger; a middle lid having a groove-shaped recess part that communicates with each cell chamber through the valve body; and a airtight sheet for covering an opening surface of the recess part so that the recess part functions as a gas discharge pathway. In the lead storage battery, the airtight sheet is composed of a base material and a label material filled with adhesive paste, and the label material has an adhesion after 24 hours from pasting based on JIS Z 0237 of 18.0 N/25 mm or larger, and has a ball tack number based on J-DOW method of JIS Z 0237 equal to 11 or larger.

Description

  The present invention relates to a control valve type lead storage battery, and more particularly to a path for exhausting gas inside the battery.

  In a lead-acid battery for in-vehicle use, a technology for reducing maintenance opportunities such as water replenishment has been widely demanded. In order to reduce maintenance opportunities, it is necessary to prevent the electrolyte from decreasing. Specifically, it is necessary to efficiently recirculate the electrolyte solution that is about to be released to the outside as the gas inside the battery is exhausted.

  In recent years, in lead-acid batteries for in-vehicle use, a top flat shape in which the upper surface of the case is flat is becoming mainstream. In order to establish this top flat shape, as in Patent Document 1, a technique has been devised to cover the inner lid with a labyrinth structure that can recirculate electrolyte droplets while selectively exhausting only gas, with the upper lid. ing. On the other hand, as disclosed in Patent Documents 2 to 3, the liquid port stopper provided with a structural device for refluxing the electrolyte droplets is arranged in substantially the same plane as the lid, and this liquid port is secured while ensuring a gas exhaust path. A technique for sticking a resin sheet so as to cover the stopper has been devised.

  In particular, in recent years, hybrid cars that take fuel efficiency and the environment into consideration have been spreading. In the case of this hybrid car, the lead storage battery is often mounted in the rear part of the luggage space in consideration of the positional relationship with other electric devices mounted on the vehicle. Along with this, since a high maintenance-free characteristic is required for the lead storage battery, a control valve type lead storage battery that absorbs internal gas at the cathode is adopted. However, it is necessary to assume an abnormality in which a charging current exceeding the gas absorption capacity of the cathode is supplied to the control valve type lead-acid battery and the gas inside the battery is exhausted. Therefore, in order to prevent the gas from leaking into the vehicle interior and being filled, an exhaust hose for guiding the exhausted gas to the outside of the vehicle at once is connected to the control valve type lead storage battery. It is a simple and effective means to attach a resin sheet as shown in Patent Document 4 as an airtight sheet to this control valve type lead storage battery and collect the gas exhausted from a plurality of cells in one place. It is thought that.

Japanese Patent Laid-Open No. 08-022815 JP-A-2005-276741 JP 2009-2108030 A JP 2003-045394 A

  However, even if the technology of Patent Document 4 is applied to a control valve type lead-acid battery, when it is continuously used under unexpected usage conditions, the hermetic sheet may lose its utility and cause a malfunction in the vehicle interior. I found out.

  The present invention solves this problem, and an object of the present invention is to provide a highly safe lead-acid battery that does not cause a problem in the passenger compartment even under unexpected usage conditions in a vehicle.

  In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention includes a battery case that is internally partitioned into a plurality of cell chambers, and a valve that exhausts gas when the internal pressure exceeds a predetermined value. A body is provided for each cell chamber, and an inner lid having a groove-like recess communicating with each cell chamber via these valve bodies, and an airtight covering the open surface of the recess so that the recess serves as a gas exhaust path A lead storage battery comprising a sheet, wherein the airtight sheet is composed of a base material and a label material filled with a paste material, and the label material has an adhesive strength of 18.0 N / 25 mm or more after 24 hours of application according to JIS Z 0237 method. And a ball tack number based on the J-DOW method of JIS Z 0237 method is 11 or more.

  Furthermore, the invention according to claim 2 of the present invention is the lead storage battery of claim 1, wherein the open surface of the recess is covered with an upper lid having substantially the same linear expansion coefficient as the base material of the hermetic sheet, and the upper lid is further sealed with the hermetic sheet. It is characterized by being covered with.

  The lead storage battery according to claim 2 is characterized in that a part of the upper lid is joined to the outer peripheral edge of the recess.

  According to a fourth aspect of the present invention, in the lead storage battery of the third aspect, the joining means is fitted, mechanically welded, or chemically bonded.

  Further, the invention according to claim 5 of the present invention is characterized in that, in the lead storage battery of claim 2, the outer periphery of the airtight sheet is increased by 5 mm or more with respect to the upper lid.

  As a result of intensive studies by the present inventors, the present inventors have found the true cause of the problems that the control valve type lead storage battery suffers when the hybrid car using the control valve type lead storage battery is exposed to unexpected usage conditions, and arrived at the present invention. It came to do. The mechanism discovered by the present inventors and the logic that led to the present invention will be described in detail below.

  Even if the hybrid car is not operated for a long period of time, the vehicle consumes standby power although it is minute. In particular, since the control valve type lead storage battery adopts a configuration in which the cathode plate absorbs the gas, the electrode plate group is completely deteriorated when it is over-discharged beyond its own dischargeable capacity by the minimal current generated at this time. Specifically, in the mat type separator having a very large pore diameter, lead ions dissolved in the electrolytic solution due to overdischarge are accumulated to form dendrites, thereby inducing a short circuit. Even if recovery charging is performed from this state, the performance of the control valve type lead storage battery will not be restored.

  However, when this phenomenon also occurs on the hybrid car side, ECU control failure due to insufficient voltage of the lead storage battery occurs. In the vehicle instruction manual or the like, there is a description that the lead storage battery should be replaced when this phenomenon occurs, and therefore, lead storage batteries having defects are usually excluded in accordance with this suggestion.

  However, users who are not interested in the above-mentioned suggestion start up with a booster cable in accordance with the conventional emergency procedure for “battery rising”, and do not notice that the lead acid battery is in an unusable state. May continue to be used. In this case, the vehicle side tries to continue charging the lead storage battery with a large current of 100 A at the maximum with respect to the lead storage battery in which the voltage continues to decrease. As a result, it was finally found that the heat of electrolysis of the electrolytic solution combined with the temperature exceeded 100 ° C., and the lead storage battery itself went out of control.

  Furthermore, the present inventors have found that this thermal runaway causes the hermetic sheet to deteriorate partially before the base material itself, causing partial peeling. In such a state, it has been found that the exhaust path of the gas leading from the lead storage battery to the exhaust hose is cut off, and the off-flavor gas with sulfur odor fills the vehicle interior.

  The present invention utilizes the above-described knowledge, and in the evaluation based on the JIS Z 0237 method, the adhesive strength after 24 hours as an index of heat resistance is 18.0 N / 25 mm or more, and the adhesive strength is By using a material with a ball tack number of 11 or more based on the J-DOW method as a label material, a lead-acid battery that does not peel off an airtight sheet even when a thermal runaway occurs due to a short-circuit and does not cause problems such as a strange odor is provided. It is.

  ADVANTAGE OF THE INVENTION According to this invention, the highly safe lead acid battery provided with durability also at the time of thermal runaway can be provided by employ | adopting the label material which can endure the conditions environment at the time of unexpected abnormal handling.

The perspective view which shows an example of embodiment of the lead acid battery of this invention The longitudinal cross-sectional view of the principal part of the lead acid battery of this invention (A) The figure which shows durability of the conventional lead acid battery, (b) The figure which put together the durability of this invention and the conventional lead acid battery The figure which shows the relationship of the durable time with respect to the outer periphery dimension difference of an upper cover and an airtight sheet | seat

  Embodiments of the present invention will be described below.

  FIG. 1 is an external perspective view showing an example of an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of an essential part thereof. Here, it will be described in detail using a cathode gas absorption control valve type lead storage battery having a high maintenance-free characteristic on the assumption that it is mounted in the rear part of the luggage space.

  The battery case 1 made of polypropylene resin (PP) or the like is internally partitioned into a plurality of cell chambers by partition walls 12, and an electrode plate group (not shown, via a separator) that is a power generation element in the cell chamber. The positive electrode and the negative electrode are respectively stored in a pair and connected in series.

  In the inner lid 2 made of PP or the like, a plurality of ribs 21 opposed to the partition wall 12 of the battery case 1 protrude perpendicularly from the upper surface portion 22, and the rib 21 has a substantially central portion in the width direction of the upper surface portion 22. A concave portion 23 extends along the direction orthogonal to each other. The concave portion 23 has a length along the longitudinal direction of the inner lid 2 so as to be located in an upper region of all the spaces defined by the ribs 21 of the inner lid 2. The bottom surface 23a of the recess 23 is provided with a cylindrical valve hole portion 25 that protrudes toward the above-described section of the inner lid 2, and the valve hole section 25 allows each section of the inner lid 2 and the recess to be recessed. 23 communicates with each other.

  Then, by covering and joining the open upper surface of the battery case body 1 with the inner lid 2 so that the partition wall 12 of the battery case 1 and the rib 21 of the inner lid 2 are attached to each other, each cell chamber is separated. Airtightly closed.

  An exhaust chamber 26 in an airtight state is provided in one end portion of the inner lid 2 in the longitudinal direction. The exhaust chamber 26 communicates with the recess 23 through a vent 27 provided at an end of the bottom surface 23 a of the recess 23. Further, the exhaust chamber 26 communicates with the outside through a cylindrical exhaust hole 28 provided so as to penetrate the short side wall surface of the inner lid 2. An exhaust hose is connected to the exhaust hole portion 28, and when the control valve type lead-acid battery is mounted on an automobile, the gas in the exhaust chamber 26 is exhausted to the outside by the exhaust hose. The

  In the concave portion 23 formed in the upper surface portion 22 of the inner lid 2, a rubber plate valve body 4 which is a plate-like valve body is laid so as to be in contact with the bottom surface 23a, and a pressing mat 5 is laid thereon. Further, a flat upper lid 3 is laid on the upper lid 3, and the concave portion 23 is closed by the upper lid 3. Here, the material of the upper lid 3 is preferably the same as that of the inner lid 2. The upper surface of the upper lid 3 is provided on substantially the same plane so as not to protrude from the upper surface portion 22 of the inner lid 2.

  Further, an airtight sheet 8 is attached so as to hang on the upper surface portion 22 of the inner lid 2 so as to cover the upper lid 3. The hermetic sheet 8 is composed of a film-like base material and a label material filled with a paste material. The label material is arranged on the surface in contact with the upper surface portion 22 of the upper lid 3 and the inner lid 2, and the outer edge portion of the upper lid 3. By sealing the gap between the inner lid 2 and the side wall of the recess 23, the outer peripheral edge of the upper lid 3 is completely airtight.

  During overcharge, oxygen gas and hydrogen gas are generated in the internal space of the cell chamber that is kept airtight. When the internal pressure of the cell chamber becomes equal to or higher than the set value due to accumulation of these gases, the rubber plate valve body 4 portion that closes the valve hole portion 25 corresponding to the cell chamber presses against the pressing force of the pressing mat 5. As a result, the valve hole 25 is opened. The gas in the cell chamber flows out from the opened valve hole portion 25. These gases flow into the presser mat 5, flow through the presser mat 5, pass through the exhaust port 27, and flow into the exhaust chamber 26 provided at the end of the inner lid 2. The gas flowing into the exhaust chamber 26 is discharged to the outside of the battery case 1 through an exhaust hole 28 that communicates the exhaust chamber 26 with the outside. In the state of being mounted on the vehicle, these gases are discharged out of the passenger compartment of the automobile through the exhaust hose connected to the exhaust hole portion 28.

  In the present invention, a label material having an adhesive strength after 24 hours of application based on JIS Z 0237 method of 18.0 N / 25 mm or more and a ball tack number of 11 or more based on J-DOW method of JIS Z 0237 method is used. There is a need. The configuration of the airtight sheet 8 is important in order to allow the above-described gas to flow into the exhaust chamber 26 without leaking even under unexpected usage conditions in the vehicle.

  Since the charging system on the vehicle side includes a circuit for charging with constant voltage control of about 13.5 to 14 V, it corresponds to overcharging after the vehicle charging system in a discharged state is activated. Even when the current is applied, when the battery voltage increases with the recovery of the state of charge (SOC) and reaches the vicinity of the control voltage, the current corresponding to overcharging decreases to 1 A or less, and oxygen or hydrogen The gas generation rate also decreases to a level that can be absorbed by the cathode plate. In this way, the time at which gas is generated at a rate (large current) that cannot be absorbed by the cathode plate (current corresponding to overcharge flows) is at most several minutes, and overcharge directly leads to deterioration of the lead-acid battery. It is not usually assumed to do. Therefore, there is no difficulty in selecting the airtight sheet 8 including the label material.

  However, if the control valve type lead-acid battery, which has reached the end of its life due to a specific deterioration (dendritic short), starts up instead of being replaced by a booster cable without the user recognizing it as a life product, the charging current from the vehicle side In contrast, the lead-acid battery voltage does not recover and rise, so energization (overcharge) to the lead-acid battery continues at a relatively high current value, and finally the lead-acid battery itself, coupled with the electrolysis heat of the electrolyte. Goes out of control. As described above with reference to FIG. 5, in an experiment assuming an actual vehicle, it has been found that the overcharge current value is as extremely high as 70 to 100 A, and the temperature in the vicinity of the hermetic sheet 8 also rises to 100 to 120 ° C. The airtight sheet 8 first deteriorates the adhesive material prior to the base material itself and causes partial peeling. Therefore, the gas exhaust path leading from the lead storage battery to the exhaust hose is cut off, and a strange odor gas with a sulfur odor is generated. Resulting in.

  In the present invention, the label material of the airtight sheet 8 is avoided in order to avoid a problem in which a bad odor gas with a sulfur odor is generated even when the user falls under unexpected usage conditions as described above due to insufficient recognition of the user. (Specifically glue material) The heat resistance and adhesive strength of the adhesive material are improved, and in the evaluation based on the JIS Z 0237 method, the adhesive strength after 24 hours as an index of heat resistance is 18.0 N / 25 mm or more. And the material whose adhesive strength is 11 or more by the ball tack number based on J-DOW method is used as a label material.

  Examples of the label material that satisfies the above-described target physical properties include a combination of a PP material for the base material and an acrylic adhesive material or a silicone adhesive material for the paste material.

  Here, it is preferable to join a part of the upper lid 3 to the outer peripheral edge of the recess 23 because the position of the upper lid 3 is fixed and the positional relationship with the airtight sheet 8 is stabilized. Examples of the joining means include fitting, mechanical welding (such as ultrasonic welding), or chemical bonding. By the way, while a projection called a director is often partially arranged on the surface facing the upper lid 3 of the inner lid 2, for example, in ultrasonic welding, the welding itself between the inner lid 2 and the upper lid 3 also passes through the director. As a result, a complete seal is not possible. Here, it is not practical to arrange the directors over the entire surface and perform sealing by ultrasonic welding in consideration of investment for making the ultrasonic welding machine have a high output specification. On the other hand, in the case of the present invention, since the airtight sheet 8 is simply configured using an appropriate label material, the manufacturing process of the conventional airtight sheet 8 can be diverted, so that it is inexpensive. From the above, as a configuration of the present invention, as shown in FIGS. 1 and 2, a part of the upper lid 3 is ultrasonically welded to the outer peripheral edge portion of the concave portion 23 of the inner lid 2 through a director. It is essential to cover the part with the airtight sheet 8. This is the same when this part is joined by another method. On the other hand, even if the upper lid 3 is omitted and the concave portion 23 of the inner lid 2 is covered with the airtight sheet 8, the effect of the category required by the present invention occurs.

  In the case of the embodiment of FIGS. 1 and 2 in which the open surface of the recess 23 is covered with the upper lid 3 and the upper lid 3 is further covered with the airtight sheet 8, the upper lid 3 is made of a material having substantially the same linear expansion coefficient as the base material of the airtight sheet 8. Must be used. For example, when the upper lid 3 is made of PP and the base material of the airtight sheet 8 is made of polyethylene terephthalate resin (PET), a difference in the expansion amount occurs at high temperatures due to the difference in the linear expansion coefficient between PP and PET, and the degree of sealing. Decreases.

  Furthermore, by making the outer periphery of the airtight sheet 8 larger than the upper lid 3 by 5 mm or more, it is possible to keep the sealing performance even if there is a slight difference in the amount of elongation between the upper lid 3 and the base material of the airtight sheet 8. It is preferable because it is possible.

Example 1
A lead storage battery (rated voltage: 12 V, rated capacity: 48 Ah) similar to that shown in FIGS. 1 and 2 is constructed (upper cover 3 is made of PP), and the gas generation rate when overcharged at 100 A is based on Faraday's law Calculated. Next, after performing piping processing on each cell chamber, in the evaluation based on the JIS Z 0237 method, the adhesive strength after 24 hours of application is 12.5 N / 25 mm, and the ball tack number based on the J-DOW method is 9. An airtight sheet 8 having a label material was attached. This lead storage battery is referred to as a battery A. On the other hand, in the evaluation based on the JIS Z 0237 method, an airtight sheet 8 having a labeling material whose adhesive strength after 24 hours is 18.0 N / 25 mm and whose ball tack number is 11 based on the J-DOW method is applied. Let the lead acid battery be battery B. In each of the batteries A and B, the outer periphery of the airtight sheet 8 was 5 mm larger than the upper lid 3.

  Four of each of these lead storage batteries were prepared and placed in a thermostatic bath at 100 ° C., and air having the same flow rate as that calculated above was forcibly injected into each cell chamber. And the sealing state of the airtight sheet | seat 8 was continuously measured via the internal pressure gauge, and the durable time (time required until seal | sticker leak, but cut off in 60 minutes) was calculated | required. An example of the durability of the battery A is shown in FIG. 3A, and a summary of the durability of the batteries A and B is shown in FIG.

  Whereas the battery A using the airtight sheet 8 having the conventional physical properties causes seal leakage with the peeling of the airtight sheet 8 in about 8 to 15 minutes, the battery B using the airtight sheet 8 of the present invention is In either case, it was confirmed that no seal leakage occurred for 60 minutes. In the case of continuous overcharge with a large current of 100A in the actual on-vehicle state, even if all of the non-fixed (free) electrolyte is electrolyzed into gas, theoretically it will last only about 30-40 minutes at most. Considering it, it can be seen that the safety of the battery B which does not cause seal leakage after 60 minutes is very high.

  In addition, although the airtight sheet | seat 8 which has various physical properties was prepared and the same evaluation was performed, the test result was the same as that of the battery B. In all cases, in the evaluation based on the JIS Z 0237 method, the adhesion was 24 hours after application. Only those having a label material having a force of 18.0 N / 25 mm or more and a ball tack number of 11 or more based on the J-DOW method.

(Example 2)
A lead storage battery was constructed in the same manner as the battery B except that the outer periphery of the airtight sheet 8 was made larger by 1 to 11 mm with respect to the upper lid 3 with respect to the battery B described above, and the same evaluation as in Example 1 was performed. Went. FIG. 4 shows the relationship of the endurance time (time required until seal leakage, but cut off in 60 minutes) with respect to the outer peripheral dimension difference (one side) between the upper lid 3 and the airtight sheet 8.

  When this difference is 4 mm on one side, the endurance time is about 30 minutes (almost the same as the endurance time required in the market). On the other hand, if the difference is 5 mm or more on one side, the endurance time of 60 minutes or more can be secured. Recognize.

  As described above, according to the configuration of the present invention, it is understood that the sealing performance is sufficiently maintained even in an unexpected situation in which a lead storage battery that has caused a dendrite short or the like is misused.

  The present invention provides a lead-acid battery that exhibits high safety even when it reaches the end of its life, and not only has high industrial applicability, but also has great utility.

DESCRIPTION OF SYMBOLS 1 Battery case 2 Middle cover 3 Top cover 4 Rubber plate valve body 5 Pressing mat 8 Airtight sheet 9 Terminal 12 Partition 21 Rib 22 Upper surface part 23 Recessed part 23a Bottom face 25 Valve hole part 26 Exhaust chamber 27 Exhaust port 28 Exhaust hole part

Claims (5)

A battery case that is internally partitioned into a plurality of cell chambers, and a valve body that exhausts gas when the internal pressure reaches a predetermined value or more are provided for each cell chamber. A lead-acid battery comprising an inner lid having a groove-shaped recess communicating with the air-tight sheet covering the open surface of the recess so that the recess becomes a gas exhaust path,
The airtight sheet consists of a base material and a label material filled with a paste material,
The label material should have an adhesive strength of 18.0 N / 25 mm or more after 24 hours of application based on JIS Z 0237 method and a ball tack number of 11 or more based on J-DOW method of JIS Z 0237 method. Lead acid battery characterized by. The lead storage battery according to claim 1, wherein the open surface of the recess is covered with an upper lid having substantially the same linear expansion coefficient as that of the base material of the hermetic sheet, and the upper lid is further covered with the hermetic sheet. The lead storage battery according to claim 2, wherein a part of the upper lid is joined to an outer peripheral edge of the recess. The lead-acid battery according to claim 3, wherein the joining means is fitted, mechanically welded, or chemically bonded. The lead acid battery according to claim 2, wherein an outer periphery of the airtight sheet is increased by 4 mm or more with respect to the upper lid.

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