JPH09120845A - Sealed secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the gas pressure in a secondary battery accurately at all times by furnishing a pressure sensor which is equipped with a draft hole leading to the inside of battery, and attaching a fixing threaded part of this pressure sensor through a ring-shaped packing to a lid plate of a battery jar in such a way as protruding into the battery. SOLUTION: A draft hole 15 leading to the inside of a battery is provide on a fixing treaded part 17 of a pressure sensor vessel 13 in which a diaphragm 20 is installed. If this threaded part 17 is attached to a lid plate 3a of a battery jar 1 through a ring-shaped packing 18, the part 17 protrudes into the jar 1 and the gas pressure in the battery 1 can be measured accurately at all times. Because the pressure sensor can certainly be mounted in a narrow space, a sealed secondary battery is accomplished, which can be embodied small and ensures the stability in the air-tightness for a long period of time.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a sealed secondary battery,
In particular, it relates to a sealed secondary battery provided with a pressure sensor for constantly measuring the gas pressure in the battery.

[0002]

2. Description of the Related Art Sealed secondary batteries of various shapes and sizes in various battery systems have been developed and put into practical use in many fields because of the advantage of reducing or eliminating complicated maintenance.

As a backup emergency power source for a large computer or the like and a mobile body driving power source for an electric vehicle or the like, an assembled battery in which several tens of cells of a relatively large capacity secondary battery of at least several tens Ah are connected in series is used. Is used. Especially,
Power sources for electric vehicles are not only conventional lead-acid type and nickel-cadmium type, but recently, due to the demand for higher energy density, a new nickel-metal hydride type (usually normal type) hydrogen storage alloy is used for the negative electrode. , Nickel-hydrogen system) has been developed and is being adopted.

Since such a sealed secondary battery for an electric vehicle is required to have an ability to accept quick charge, it is of course necessary to impart overcharge resistance in designing the battery. The control method is adopted in which the change in the charging current is measured to detect the overcharged state to reduce or cut off the charging current. Because of the functional nature of electric vehicles, they are used seasonally and in a wide range of areas, so the sealed rechargeable batteries that power them are not only charged at a wide range of environmental temperatures, but are also discharged, stored, stored, and even vibrated. It is necessary to predict that it will be used under conditions such as shock, acceleration, etc.

Further, since it is important to have a long life from the viewpoint of economy, the reliability of quick charging is improved and
There is a strong demand for continuous measurement of the gas pressure in the battery in order to clarify the long-term behavior of the battery.

Here, the pressure control method and the pressure detection method will be exemplified. In the quick charger, calculate the output of the pressure detector that is placed on the outer surface of the battery pack of the nickel-cadmium battery or inside the battery, and stop the charging when the pressure exceeds a predetermined value, or change the charging voltage. It is used in combination with a detection means for control, and there has been proposed a strain gauge fixed as a pressure detector on the outer frame surface of the assembled battery (see, for example, Japanese Patent Laid-Open No. 4-79732).

Further, a pressure sensor is inserted between the inner wall of the battery pack case accommodating a plurality of cells and the cells in contact with it, or a rigid beam is installed on the outer wall at one end of the block type battery case of the sealed lead acid battery. However, between the beam and the outer wall of the battery case, a pressure detection device that detects the expansion and contraction of the battery case and has a contact point that closes when the pressure exceeds a certain level is inserted. A method of detecting swelling as a pressure change (see, for example, JP-A-62-190667, JP-A-5-326027, and JP-A-6-5123) has been proposed.

An example thereof will be described with reference to FIG. FIG.
42 is a rechargeable battery in a rectangular battery case, and 5 cells are composed of two fixing plates 43, a fixing rod 44, and a tightening nut 45.
The assembled battery 41 is sandwiched by A flat plate strain gauge type pressure sensor 46 is inserted between the cell outer wall at the right end and the inner side of the fixed plate 43, and the pressure is detected by the expansion and contraction of the battery case. Reference numeral 47 is an input / output line. As a similar one, there is a sealed type storage battery in which a flat plate-shaped pressure sensor is inserted between the inner wall of the battery case and the electrode plate group in contact therewith (for example, Japanese Laid-Open Patent Publication No. 62-168351, Japanese Utility Model Publication No. Hei Kaihei). JP-A-5-84149, JP-A-5-1211
03, etc.).

Further, a thin pressure-sensitive portion on the battery cover and a pressure switch which is turned on / off when a constant pressure is produced due to the change.
Alternatively, a device provided with a switch mechanism for outputting a battery voltage (for example, Japanese Utility Model Laid-Open No. 6-5121 and Japanese Utility Model Laid-Open No. 6-512).
No. 5, etc.), or a pressure switch provided on the lid as a pressure detecting means, and actuating an alarm display means when a predetermined pressure is reached (see, for example, Japanese Utility Model Laid-Open No. 6-17117), or liquid of lead acid battery. A structure in which a pressure switch function that operates with the gas pressure inside the battery is added to the mouth plug and the exhaust plug together with a safety valve and the like to prevent overcharging (for example, JP-A-6-283209 and JP-A-6-5124). It has been proposed to incorporate a switch function, which operates when the pressure reaches a certain value, into a battery.

[0010]

An emergency power source such as a computer power source and a driving power source for a mobile body such as an electric vehicle are connected in series with a relatively large secondary battery of several tens Ah or more and several tens of cells or more. It is used. Recently, new high-capacity sealed secondary batteries such as alkaline secondary batteries such as sealed nickel-cadmium storage batteries and nickel-hydrogen storage batteries have been developed in response to requests for improved handleability and higher energy density. It is being adopted.

In many cases, these sealed secondary batteries are rapidly charged as described above, and in addition to the conventional pressure detection and pressure switch means, in addition to charge control by the transition of battery voltage and temperature during charging. It is becoming more and more controlled. However, in mobile applications, especially for mobile applications mainly for electric vehicles, in addition to rapid charging, large current discharge, various usage conditions under a wide range of environmental temperatures, etc.
To ensure stable performance during long-term cycles, the various characteristics of the battery are constantly measured during charging / discharging, resting, and leaving.
It is desirable to control the gas pressure in the battery, and it is required to always accurately grasp the pressure transition.

For this purpose, however, the above-mentioned conventional means for detecting the pressure inside the battery is insufficient or unsuitable for continuously and accurately measuring the transition of the gas pressure inside the battery. It was

That is, the gas pressure generated in the battery is
As the expansion pressure of the flat wall of the battery case, the outer frame of the assembled battery,
When detecting with a pressure sensor such as a flat plate strain gauge inserted between the beam, fixed plate, etc. and the wall surface of the battery case, continuous pressure change can be measured, but it can be installed in a relatively small size. Since the electrode plate group in the battery case swells due to repeated charging and discharging and acts as a pressing force to the inner wall of the battery container, the pressure detected by the pressure sensor of this method is the pressure generated by the gas generated in the battery and the electrode plate swelling. It was a combined force with the pressing force due to, and it was not possible to accurately detect only the gas pressure inside the battery.

Furthermore, the coefficient of expansion of the electrode plate group (which may temporarily contract depending on the conditions) varies depending on the charging / discharging conditions, the environmental temperature, etc. and also varies depending on the configuration of each unit cell. It was not easy to correct the value, and it was an inaccurate method for measuring the gas pressure in the battery.

Further, the method of inserting the pressure sensor between the inner wall of the battery case and the electrode plate group is also inaccurate, and when the pressure sensor is inserted, it is necessary to separately design the electrode plate group structure, which is complicated. I could not escape it.

Further, the lid of the battery is provided with a pressure switch function for turning on / off the contact when the gas pressure inside the battery reaches a predetermined value (the above-mentioned actual flat opening 6-5121 and actual flat opening 6-51).
No. 24, Japanese Utility Model Laid-Open No. 6-17117) can be made relatively small (especially small in the height direction), but the information obtained is only a fixed value, and this fixed value is arbitrary depending on the usage conditions. It was not easy to change to, and it was not suitable for continuous measurement of gas pressure in the battery.

For the above-mentioned reasons, when it is necessary to continuously measure the gas pressure in the battery, the smallest pressure sensor used for management measurement of pneumatic equipment or hydraulic equipment should be selected. It is actually used.

FIG. 8 is a side view showing an example of the small-sized pressure sensor. In FIG. 8, the pressure sensor 51 is a container 52 containing a pressure-sensitive function in which a thin film strain gauge or the like is arranged inside a pressure-sensitive diaphragm. And a screw portion 54 for fixing to a device. The screw portion 54 is provided with a vent hole 55 communicating with the pressure receiving portion of the pressure sensitive function and a screw thread 56 on the outer periphery, and is screwed and fixed to the device via an O-ring 57. Reference numeral 53 is a sealing tightening nut, and 58 is an input / output cord. The diameter φ3 of the screw thread 56 is small and 10 to 15
mm.

On the other hand, 50 to 50 applied to the electric vehicle, etc.
Many 120Ah class sealed secondary batteries are generally prismatic, the positive and negative pole terminal and safety valve are arranged on the lid, and the lid plate thickness of the lid is 3mm. It is about 1 mm in the front and rear, and in the case of metal. The pressure sensor 51 is provided with a screw hole at an empty position on the upper surface of the cover plate,
When the screws are directly fixed by screwing, the cover plate is thinner than the screw diameter of the sensor and the gas pressure in the battery is 3 to 10 kgf.
The fixing strength and airtightness corresponding to / cm ² or more could not be maintained.

Therefore, as an improvement measure, a joint use of a tightening nut plate for reinforcement was examined on the inner surface side of the lid plate, but a nut plate (size of about 20 to 25 mm square) corresponding to a thread diameter of 10 to 15 mm was examined. It was difficult to secure a space to fit the inner surface of the cover plate and tighten it, and it could not be put to practical use.

As can be seen from Japanese Patent Laid-Open No. 57-196481, there is a method in which a pressure sensor is brought into contact with a hole provided in a cover plate by using a rubber attachment for a liquid port plug, but the above gas pressure is used. It was unsuitable from the point of view of reliability to endure for a long time and hermetically fix.

For this reason, the sealed secondary battery is
As a method of fixing the pressure sensor in an airtight manner, there has been a conventional method using a sensor mounting adapter 60 as shown in FIG. FIG. 9 is a side view of a main part in which the short side of the lid is cut away. The adapter 60 is made of, for example, stainless steel, a sensor screw hole 61 corresponding to the screw part 54 of the pressure sensor 51 is provided above, and a valve is provided below. A valve seat screw hole 63 and a gas space 62 that fit the screw portion 65a of the seat 65 are provided. The valve seat 65 is formed by removing the valve body and the valve cover in the safety valve fixed on the valve opening 67 of the lid body 66 of the battery. The valve seat 65 is provided with a screw thread for screwing the adapter at the rising portion of the valve seat 65.
5a. Reference numeral 68 is a safety valve newly provided to ensure safety during the test. As shown in FIG.
Through the O-ring 56 into the sensor screw hole 61 of the adapter 60 attached to the valve seat 65 fixed to the lid 66, the screw portion 5
The pressure sensor 51 is airtightly fixed by screwing 4 on. In addition, 68 is a pole terminal flange part which protrudes in a battery. In the case of the assembled battery 41 as shown in FIG.
As shown in 0, the pressure sensor 51 may be fixed to the side surface of the adapter 60.

When measuring the internal gas pressure of a small number of cells in a laboratory, the height of the battery at the pressure sensor mounting portion is shown in FIG.
Also, there was no particular problem even if the size increased as shown in FIG. However, in the above-mentioned electric vehicle, 100 to 20
It is necessary to use 0 or more batteries connected in series, and measure the internal gas pressure of the cells in a distributed form for at least several tens of cells, and the space for accommodating the batteries is rather strictly limited. Therefore, FIG. 9 and FIG.
The pressure sensor mounting method shown in FIG. 0 has a problem that it is difficult to accommodate the battery as an assembled battery.

Further, since the mass of this portion is large, it is easily affected by vibrations and impacts in an electric vehicle and the like, which causes a problem in terms of ensuring airtightness, and thus it is unsuitable for long-term use.

The present invention is to provide a sealed secondary battery which can be miniaturized by reliably mounting a pressure sensor in a narrow space and can continuously and continuously measure the gas pressure inside the battery for a long period of time. This is an issue.

[0026]

Means for Solving the Problems In order to solve the above-mentioned problems, according to the means for fixing the pressure sensor to the battery lid, a fixing screw portion having a thin tubular shape is projected at the center of the abutting mounting surface. A pressure sensor that has a pressure-sensitive sensor function is formed in a sensor container that has a vent hole communicating with the inside.
Through the annular packing arranged on the mounting surface of the sensor container, in the fixing screw hole provided on the lid plate side of the sealed secondary battery,
The pressure sensor is airtightly fixed on the cover plate by tightening the fixing screw portion.

Further, in order to improve airtightness, an annular groove for accommodating an annular packing is provided on the mounting surface at the periphery of the fixing screw portion, or a portion where the annular packing is in contact with the mounting surface of the sensor container and the battery cover plate. Further, it is effective to provide an adhesive sealant film layer made of asphalt pitch or electrolytic solution resistant grease or the like.

Further, when the cover plate is made of synthetic resin,
A fixing screw plate having a fixing screw hole may be provided on the battery plate inner surface side of the lid plate to reinforce the fixing strength.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention can be used as a power source for driving an electric vehicle, and the invention according to claim 1 is that a sensor container has a small-diameter thin tubular fixing screw portion formed in the central portion of the mounting surface. The cover plate surface is fixed by screws. As a result, the occupied area and height of the portion where the pressure sensor is mounted and fixed can be reduced,
It becomes easy to mount the pressure sensor on the cover plate surface of the battery, and the size of the whole single battery or assembled battery can be reduced.

Further, since the mounting surface and the annular packing are subjected to an equal tensile force by tightening the small-diameter, small-pitch fixing screw portions projecting to the central portion of the mounting surface, they are tightened on the lid plate surface. The pressure sensor can be fixed to the lid plate in a highly airtight and stable state.

In the invention according to claim 2, the annular packing is housed and tightened in the annular groove provided on the mounting surface of the sensor container, whereby the compression rate of the annular packing is regulated and the mounting surface is fixed. Since the upper surface of the cover plate is evenly contacted, the airtightness of the fixed portion can be improved.

In the invention according to claim 3, the sealant film layers are provided on the upper and lower surfaces of the annular packing, whereby the airtightness and liquid leakage resistance of this portion can be improved.

Further, in the invention according to claim 4, since it is fixed to the lid with the small-diameter fixing screw portion formed in the center of the mounting surface of the sensor container, the area of the fixed portion occupying the inner surface of the lid plate can be reduced. Yes, if you use a synthetic resin lid plate,
It is possible to install a fixing screw plate that is fixed to the lid plate, and it is possible to fasten the pressure sensor on the lid plate with stable airtightness and fixing strength.

(Embodiment 1) As Embodiment 1 of the present invention, a case of a prismatic 50-120 Ah class alkaline sealed secondary battery will be described with reference to FIGS. 1 to 6.

1 and 4 show a first embodiment using a lid made of synthetic resin, and FIGS. 2 and 3 show an example of a pressure sensor used therefor.

FIG. 1 (A) is an external perspective view of a prismatic sealed secondary battery, and FIG. 1 (B) is a top view of its lid portion. In FIGS. 1 (A) and 1 (B), polypropylene or the like is used. In the battery case 1 made of synthetic resin, for example, a plurality of positive and negative electrode plates mainly filled with a nickel active material and a hydrogen storage alloy are alternately stacked with a separator interposed therebetween and impregnated with a predetermined alkaline electrolyte. The electrode plate group 2 (see FIG. 4) thus configured is housed.

The lid 3 has positive and negative pole post terminals 4 and a safety valve 5 mounted at predetermined positions on the lid 3a made of synthetic resin,
A pressure sensor 6 is attached to one end of the lid body 3 by tightening and fastening a lid plate 3a and a fixing screw plate 7 provided on the inner surface thereof. After connecting the electrode plate leads derived from the electrode plate group 2 to the electrode pole terminals 4 of the lid body 3 (see FIG. 4), the peripheral edge of the lid plate 3a is sealed to the open end of the battery case 1 by welding or the like. Dressing part 8
And sealed to form an alkaline sealed secondary battery 9. Reference numeral 10 is a mounting boss, 11 is a mounting hole, and 12 is an input / output cord.

FIG. 2 is a side view of the pressure sensor 6 with a main portion cut away. Reference numeral 13 is a sensor container made of metal such as stainless steel for accommodating the pressure-sensitive function portion, which is attached to the battery cover plate 3a at one end. A circular mounting surface 14 is provided, and a ventilation hole 15 for introducing a measurement gas is provided in the center of the mounting surface 14.
A thin tubular fixing screw portion 17 provided with a screw thread 16 on the outer peripheral surface is formed to project. The sensor container 13, the mounting surface 14, and the fixing screw portion 17 may be individually manufactured and airtightly integrated by welding or the like, but in FIG. 2, in order to omit an inspection process such as airtightness and welding strength. The one that was manufactured integrally without being divided was used. Regarding the materials used,
A corrosion-resistant metal that resists splashing of the electrolytic solution contained in the measurement gas is used, and for example, alkali-resistant stainless steel or a steel material plated with nickel is used. Mounting surface 14
Regarding the dimensional relationship of the fixing screw portion 17, the outer diameter of the sensor container 13 of the downsized pressure sensor 6 is 12 to 15 mm.
On the other hand, the outer diameter of the mounting surface 14 is 10 to 12 mm, the thread diameter of the screw thread 16 of the fixing screw portion 17 protruding in the central portion is 3 to 4 mm, and the vent hole for introducing the measurement gas is in the central portion. A through hole of about 1 mm is provided as 15.

If the diameter of the annular packing 18 made of synthetic rubber or the like, which is interposed between the mounting surface 14 and the cover plate 3a and is hermetically sealed, is made smaller, it is more uniformly compressed and stable airtightness is easily obtained. The withstand pressure can also be increased.

Further, the annular packing 18 is pressed to 10K.
The mechanical strength withstanding a gas pressure of gf / cm ² or more can be secured if the screw diameter of the fixing screw portion 17 is around 3 mm. Based on these two experimental findings, the screw diameter of the fixing screw portion 17 is 3 in consideration of the outer diameter of the sensor container 13 and the shape of the lid.
It may be selected from the range of up to 5 mm.

The length of the fixing screw portion 17 is 1 to 2 mm depending on the depth of the screw hole portion of the lid plate 3a and the thickness of the annular packing 18.
It is preferable that the dimension has a margin of 5 to 10 mm.

The mounting surface 14 of the pressure sensor 6 and the cover plate 3a
As described above, the annular packing 18 such as a rubber O-ring is interposed therebetween, and the fixing screw portion 17 is screwed and fixed to the fixing screw provided on the cover plate 3a. In this screw tightening work, in order to uniformly regulate the compression rate of the annular packing 18 to a constant size, it is desirable to tighten the screw while checking the size with a torque wrench. In order to facilitate this work and stabilize the hermeticity, the annular packing 1 is attached to the mounting surface 14.
It is desirable to provide the annular groove 19 having a depth corresponding to a predetermined compression height of 8 (for example, a depth of 80% of the annular packing height). This makes the mounting surface 14 hit and stop,
The screw tightening work can be easily performed.

Next, the pressure-sensitive functional portion housed in the sensor container 13 will be described. A diaphragm 20 made of a thin metal plate serving as a gas pressure receiving surface is airtightly fixed to the inner surface of the mounting surface 14 via an annular ring 22 forming a pressure receiving chamber 21 for evenly receiving the gas pressure. On the back surface of the diaphragm 20, a pressure sensitive portion 23 is formed by fixing a silicon semiconductor resistance strain sensor or a metal foil resistance strain gauge such as nichrome or advance alloy. A semiconductor resistance strain sensor is used in a bridge connection for high sensitivity.

These sensors detect a change in resistance value due to pressure as a change in voltage, amplify and output the change, and at the same time, a measurement processing circuit in which an electric circuit such as a DC power source for giving a predetermined constant current and a constant voltage is blocked. 24 and the input / output cord 12 for outputting the power input and the detected value to the outside are connected and housed as shown in the drawing, and the open end of the upper surface of the sensor container 13 is sealed with a resin casting, a metal lid or the like to apply pressure. The sensor 6 is configured.

FIG. 3 is a block circuit diagram showing an example of the above-mentioned pressure-sensitive function portion. The measurement processing circuit 24 detects and amplifies a minute voltage output of the silicon semiconductor resistance strain sensor 25 and outputs it to the input / output code 12. The integrated circuit includes a circuit, a circuit that corrects the influence of the environmental temperature, and a circuit that controls and corrects the power supply voltage and current applied to the resistance strain sensor 25, if necessary. When the sensor container 13 has a cylindrical outer shape, a notch for screw tightening is provided on the side surface of the sensor container 13 or the side surface of the mounting surface 14 in order to facilitate the screw tightening of the fixing screw portion 17. Is desirable.

FIG. 4A is a partially cutaway side view of the short side of the battery according to the first embodiment shown in FIG. 1 in which the above-mentioned pressure sensor 6 is mounted, and a method for fixing the pressure sensor 6 to the lid body 3. It shows an example of.

The cover plate 3a made of an alkali-resistant synthetic resin such as polypropylene resin has a fixing hole 25 into which the fixing screw portion 17 of the pressure sensor 6 is inserted and a fixing screw as shown in FIG. 4 (B). A mounting boss 10 is provided for inserting the plate 7 into the mounting hole 11 and crushing and fixing the head with a heat press or the like. The fixing screw plate 7 may be fixed to the cover plate 3a by a hot melt adhesive or the like.

The fixing screw plate 7 is made of a stainless steel plate or the like and is provided with a screw hole 26 having a screw diameter that engages with the screw thread of the fixing screw portion 17 of the pressure sensor. As described above, since the screw diameter of the fixing screw portion 17 is in the range of 3 to 5 mm, the width of the fixing screw plate 7 is as small as about 6 to 9 mm in consideration of the screw tightening fixing strength. It can be installed in a small space where the safety valve 5, the pole pillar flange 27 below the pole terminal 4, the pole group 2, and the pole current collector 28 to which the pole leads 7 are welded are arranged. Becomes

As a result, even when a synthetic resin lid plate is used, the fixing screw portion 17 is strongly screwed, and the mounting surface 14 of the pressure sensor 6 into which the annular packing 18 is inserted is hermetically sealed on the surface of the lid plate 3a. Can be firmly fixed. In addition, in a battery system using an electrolytic solution such as an alkaline electrolytic solution which is susceptible to leakage due to creeping under the influence of temperature and humidity, as shown in FIG. 4 (A) and FIG.
The mounting surface 14 that contacts the upper and lower surfaces of the annular packing 18 and the upper peripheral portion of the fixing hole 25 of the lid plate 3a are coated with a sticky sealing agent such as a paint mainly containing asphalt pitch or a fluorinated grease to seal. After forming the material film layer 29, it is effective to fix the fixing screw portion 17 by screwing. As a result, it is possible to prevent liquid leakage from the peripheral edge of the fixed portion for a long period of time, and it is possible to reliably prevent minute gas leakage that tends to occur when the gas pressure inside the battery is high in an environment where the temperature changes greatly.

Further, when the cover plate 3a made of synthetic resin is used and the pressure sensor 6 is attached only to some or arbitrary batteries, the position corresponding to the fixing hole 25 of the cover plate 3a is shown in FIG. The recessed portion 30 and the cutout portion 31 are provided so that the annular thin portion 3
When the pressure sensor 6 is mounted by molding so as to form 2, the accurate fixing hole 25 can be easily provided at a predetermined position by punching or the like, which is convenient.

Next, as shown in FIG. 6, when the cover plate is a metal plate.
As will be described with reference to (A) and (B), the lid plate in this case is a nickel-plated steel plate having a thickness of about 0.8 to 1.5 mm, a nickel-based alloy plate, etc. It is formed by press molding using a metal plate. In FIG. 6 (A), a rising portion 34 is provided at a predetermined position of the metallic lid plate 33, and the fixing screw portion 1 of the pressure sensor 6 is provided.
A screw hole 36 is formed by tapping a screw thread 35 that engages with the screw 7.

In FIG. 6B, the reinforcing screw plate 3 is used.
7 (thickness of 2 to 3 mm or more) is fixed to a predetermined position of a metal cover plate 38 by a method such as welding and pressure bonding, and a screw hole 36 in which a screw thread 35 is formed by tapping as described above.
Is provided.

As described above, the metal lid plates 33, 38 having the screw holes 36 are used, and the metal lid plates 33, 38 are provided at the open ends of the metal battery case containing a predetermined electrode plate group. After the ribs 39, 40 are hermetically sealed by welding or the like, the fixing screw portion 17 of the pressure sensor 6 is screwed into the screw hole 36 via the annular packing, so that the pressure sensor 6 can be tightly fastened. Also in the second embodiment, as described above, if a sealing agent film layer such as asphalt pitch is provided on the peripheral portion of the upper surface of the screw holes 36 of the metal lid plates 33 and 38, the sealing is similarly performed. The long-term leakage resistance of the part can be improved.

As can be seen from the above description, the pressure sensor 6 is a synthetic resin lid or a metal lid without lowering workability either when the lid is assembled or after the battery is assembled and sealed. It can be securely mounted in a narrow space of the body in an airtight state. In particular, in the case of a synthetic resin lid, gas leakage and mounting strength were insufficient even with a gas pressure of 1 to ² Kgf / cm ² in the screw hole of the resin alone, but the fixing screw plate 7 for reinforcement is dimensionally By enabling the combined use, even if the gas pressure inside the battery is ^{3 to} 10 Kgf / cm ² or more, it is possible to prevent the gas from leaking from the portion where the pressure sensor 6 is mounted and the electrolyte from leaking out.

In the above description, the case where the synthetic resin lid or the metal lid is used in the prismatic sealed nickel-hydrogen-based alkaline secondary battery has been described, but other sealed secondary batteries of the same form are described. Further, the present invention can be applied to a cylindrical secondary battery of several tens of Ah class or more.

[0056]

As described above, according to the present invention, a fixing screw portion having a thin tubular ventilation hole is provided at the center of the mounting surface of a pressure sensor, and a battery is provided through an annular packing surrounding the periphery of the screw portion. Since it is screwed into the screw hole provided in the cover plate, it can be easily fixed even in a narrow space of the cover, and the battery can be downsized.

Further, the mounting surface and the annular packing can be tightened on the cover plate surface by a uniform pulling force by tightening the small-diameter, small-pitch fixing screws. It is possible to provide a sealed secondary battery capable of continuously and stably measuring the gas pressure inside the battery in a wide range of environments.

[Brief description of the drawings]

FIG. 1A is a perspective view of a sealed secondary battery according to an embodiment of the present invention, and FIG. 1B is a top view of the sealed secondary battery.

FIG. 2 is a side view of the main part of the pressure sensor in the sealed secondary battery with a partial cutaway.

FIG. 3 is a block circuit diagram of the pressure sensor.

FIG. 4A is a partially cutaway side view of the pressure sensor mounting portion of the sealed secondary battery, and FIG. 4B is a top view of the pressure sensor mounting portion.

FIG. 5 is a cross-sectional view of a main part of a lid plate in the sealed secondary battery.

6 (A) and 6 (B) are cross-sectional views each showing a modified example of a main part of a lid in the sealed secondary battery.

FIG. 7 is a side view of a conventional battery pack.

FIG. 8 is a side view of a pressure sensor in the battery pack.

FIG. 9 is a partially cutaway side view of a pressure sensor mounting portion of the battery pack.

FIG. 10 is a side view showing another example of a conventional assembled battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery case 2 Electrode plate group 3a, 33, 38 Cover plate 6 Pressure sensor 7 Fixing screw plate 13 Sensor container 15 Vent hole 17 Fixing screw part 18 Annular packing 19 Annular groove 29 Sealing material film layer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Munehisa Ikoma 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A sensor container having a thin tubular fixing screw portion having a vent hole communicating with the inside of the battery and projecting in the central portion of the mounting surface is provided with a pressure sensor having a pressure-sensitive function portion, and the pressure sensor is fixed. A sealed secondary battery in which a screw portion is screwed to a lid of a battery case accommodating an electrode plate group through an annular packing. 2. The sealed secondary battery according to claim 1, wherein an annular groove for accommodating an annular packing is provided at the periphery of the protruding portion of the fixing screw portion in the sensor container. 3. The sealed secondary battery according to claim 1, wherein an adhesive sealing material film layer is provided on the lid plate and the sensor container which are in contact with the annular packing. 4. The sealed secondary battery according to claim 1, wherein a fixing screw plate is provided on the inner surface of the lid plate.