JP4678128B2 - Sealed storage battery - Google Patents

Description

  The present invention relates to an improvement in a sealed storage battery provided with a pressure switch mechanism that cuts off a charging current in accordance with a change in battery internal pressure during charging.

  Secondary batteries used as power sources for portable devices include nickel / cadmium batteries, small sealed lead batteries, and lithium ion batteries. These secondary batteries are charged by a charging method suitable for the charging characteristics of each battery. For example, a nickel-cadmium battery is charged with a constant current, and the charging current is controlled by detecting a battery voltage drop characteristic that occurs at the end of charging. In a small sealed lead battery and a lithium ion battery, after charging at a constant current, the charging current is controlled when a constant voltage is reached.

  In alkaline storage batteries such as nickel-metal hydride storage batteries and nickel-cadmium storage batteries, there has recently been an increasing demand for rapid charging that has not been conventionally performed, for example, charging is completed within 30 minutes. Conventionally, nickel-metal hydride storage batteries perform charge control similar to that of nickel-cadmium batteries. However, if an attempt is made to perform rapid charging that is not conventional, such as the above, heat generation and gas generation occur during charging. As the internal pressure of the battery rises and the gas discharge valve operates to discharge the electrolyte together with the gas, the battery performance may be deteriorated, and it is difficult to realize rapid charging.

  As described above, when a nickel metal hydride storage battery is to be rapidly charged at a constant voltage, it involves an increase in battery temperature and an increase in internal pressure of the battery. In view of this, in particular, a storage battery having a pressure switch mechanism that cuts off a charging current in accordance with a change in pressure inside the battery has been proposed by paying attention to an increase in pressure inside the battery during charging (see, for example, Patent Document 1). ).

  In a nickel metal hydride storage battery equipped with such a pressure switch mechanism, when the battery internal pressure reaches a constant pressure during charging, the charging current is cut off, and when the battery internal pressure falls below a certain pressure, the battery is connected again. Since the pulse charging is performed in conjunction with the change of the battery, an increase in battery temperature during charging is suppressed. The configuration is shown in FIG. 7, for example.

In the example of FIG. 7, reference numeral 21 is a cap (positive electrode terminal), 22 is a lid (second terminal of the pressure switch), 23 is rubber, 25 is a battery case (negative electrode terminal), 26 is a gasket, 27 is a lead member, 28 is a switch plate (first terminal of a pressure switch), 29 is a connection terminal, 30 is an electrode group, and the battery case 25 containing the electrode group 30 is filled with an alkaline solution (not shown). The battery case can 25 is sealed (sealed) by the gasket 26, and the rubber 23 is deformed in accordance with the change in the internal pressure (battery internal pressure), so that the first terminal 28 of the pressure switch becomes the second terminal 22. The charging current is cut off by the contact / separation operation.
US Patent Application Publication No. 2002 / 0119364A1

  In the conventional sealed battery with a built-in pressure switch shown in FIG. 7 and the like, since the resilient member 23 constituting the pressure switch is disposed in the cap 21, the height of the cap 21 is increased, and the height of the cap 21 is increased. As the thickness is increased, the width of the electrode plate 30 is reduced, and the capacity of the storage battery is reduced.

  Further, the battery temperature gradually rises at the time of charging, but the rubber 23 generally softens when the temperature becomes high, and the load characteristic decreases. Therefore, the load characteristic of the rubber 23 particularly in the case of charging under a high environmental temperature. There is a possibility that the change of the charging current is remarkably disturbed and the timing of switching the charging current is disturbed, and the switch function of the pressure switch may be deteriorated.

  Further, when the switch plate (first terminal of the pressure switch) 28 moves up and down in response to the expansion / contraction operation of the rubber 23, the switch plate 28 tilts with respect to the lid (second terminal of the pressure switch) 22, and the pressure switch Since the contact / separation operation between the first terminal 28 and the second terminal 22 may be incomplete, the pressure switch function has a low reliability.

  Further, the cap 21 and the lid 22 are overlapped with each other at the peripheral edge thereof and are held in a state of being locked in a locking groove formed in the gasket 26. For this reason, if the alignment of the joint surfaces of both 21 and 22 becomes poor during assembly, or if foreign matter such as dust or dirt is present on the joint surfaces, a sufficient contact state cannot be obtained and the contact resistance increases. There was a difficulty in reducing the charge acceptance performance. In addition, sealing accuracy (sealing performance) may be deteriorated due to poor alignment during assembly or the presence of foreign matter on the joint surface. When the sealing accuracy is lowered, there is a drawback that a problem such as leakage of gas to the outside or leakage of an alkaline solution easily occurs.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a sealed battery that is always capable of stably obtaining high charge acceptance performance and having high pressure switch function.

This invention solves the said subject by making the structure of the sealed storage battery with a built-in pressure switch into the following structure.
(1) In the sealed storage battery according to the present invention, a battery case that contains an electrode group together with an alkaline solution is sealed by a metal lid, a gasket, and a connection terminal fitted in a through hole of the gasket. In addition, a built-in switch with a cap that doubles as a positive electrode terminal or a negative electrode terminal, and a switch mechanism that includes a resilient member that expands and contracts in response to changes in the internal pressure of the battery is used to cut off the charging current. In secondary batteries,
The resilient member is disposed between the inner surface of the lid and the thin portion of the gasket, the switch plate fixed to the upper portion of the connection terminal and the lid are in contact with each other, and the battery The sealed storage battery is characterized in that when the internal pressure exceeds a certain level, the elastic member contracts and the gasket deforms to separate the switch plate and the lid .

  With this configuration, the elastic member is disposed in the space between the inner surface of the lid and the gasket, so that the height of the cap is kept small compared to a storage battery in which the elastic member is disposed in the cap. Thus, the depth of the battery case can be set to be large and the width of the electrode plate can be increased, so that the battery capacity can be increased by increasing the width of the electrode plate. That is, the capacity can be increased.

(2) The sealed storage battery according to the present invention is the storage battery according to (1), wherein the elastic member is made of a metal material.

  In the configuration described in (1), the position of the elastic member is closer to the electrode plate group than in the case where the elastic member is disposed in the cap. In addition, the temperature of the elastic member is likely to rise. Conventionally applied elastic members made of rubber have the disadvantage that the reliability of the pressure switch decreases because the elastic characteristics deteriorate when the temperature rises. On the other hand, by making the elastic member a metal material, the elastic characteristics are less likely to deteriorate even at high temperatures (compared to rubber), and the battery internal pressure always changes without being affected by environmental changes. Accordingly, the expansion / contraction operation is appropriately performed, the charging current switching timing is normally maintained, and a highly reliable pressure switch function can be obtained.

(3) sealed storage battery according to the present invention, prior Symbol resilient member is a coil spring or Belleville spring conical, Ru is brought into contact with the inner peripheral end to the outer peripheral lower end portion of the holding portion of the gasket It is preferable .

  By making the elastic material a conical coil spring or a disc spring, the thickness of the elastic material can be reduced. Therefore, the battery capacity can be increased by reducing the thickness of the switch mechanism and increasing the height of the electrode plate. Can be improved. In addition, by bringing the inner peripheral side end of the spring into contact with the lower end of the outer periphery of the holding portion of the gasket, the switch plate can be translated in accordance with the expansion and contraction of the elastic member, so that a highly reliable switching function is achieved. It can be set as the battery which has.

(4) In the sealed storage battery according to the present invention, the lid and the cap are preferably joined by welding.

  By welding the lid and the cap, the joined state between the lid and the cap is improved, and it is possible to avoid the occurrence of poor joining between the two members. Thereby, since the electrical resistance in a junction part can be decreased, the charge acceptance characteristic at the time of performing quick charge improves.

  Also, by integrating the lid and battery cap in advance by welding, the efficiency of the assembly work can be significantly improved, the assembly accuracy can be improved stably, and foreign substances such as dust and dirt can be joined. Since it is possible to avoid problems such as intervening on the surface, high sealing accuracy (sealing performance) can be stably maintained. This makes it difficult for gas leaks and liquid leaks to occur.

(5) In the sealed storage battery according to the present invention, only the peripheral edge of the lid is locked to the inside of the opening end of the battery case can via a gasket, and the cap is joined to the lid by the outer surface of the lid. It is preferable that it is fixed to.

  According to the configuration described in (5), since only one plate member (primary lid) is locked in the locking groove of the gasket, the battery case can be deeper than (when locked in two layers). Can be formed. Thereby, a charge capacity (battery capacity) can be increased. Moreover, since high assembly accuracy is obtained, high sealing performance can be ensured, and the sealing performance can be stably maintained.

(6) sealed storage battery according to the present invention, the front opening edge of Kifuta is one terminal of the switch, the outer peripheral edge of the switch plate is the other terminal, for connecting the electrode group and the switch plate A connection terminal is penetrated and held by the gasket, and the switch plate is fixed to a portion of the connection terminal protruding to the battery cap side, and a holding portion of the gasket holding the connection terminal is provided on the lid. Rukoto fitted in sliding contact state with respect to the opening formed is preferable.

  According to this configuration, since the holding portion of the gasket is fitted and inserted into the opening formed in the lid in a slidable state, for example, a sealing property between the holding portion and the opening is ensured. If the outer diameter of the holding portion and the inner diameter of the opening are set as much as possible, gas leakage and liquid leakage can be more effectively prevented.

  Furthermore, since the holding portion of the gasket holding the connection terminal is in sliding contact with the opening of the lid according to the expansion / contraction operation of the elastic member, the opening of the lid is interlocked with the expansion / contraction of the elastic agent. It acts as a guide when moving up and down, and the switch plate moves parallel to the lid without being inclined. Therefore, since the switch plate and the lid are in good contact with each other, a sealed storage battery having a small electrical resistance between them can be obtained. In addition, since the switch plate and the lid are securely connected to each other, a sealed storage battery having a particularly reliable switch function can be obtained in the present invention.

  In addition, using a gasket for sealing the battery case can, for example, if the connection terminal is held at the center, the connection terminal can be displaced according to the change in the battery internal pressure. Therefore, a separate part for supporting the connection terminal is not required, so that the degree of freedom in layout is improved and the switch built-in type secondary battery can be made compact.

  In the sealed storage battery according to the present invention, since the elastic member is disposed between the lid and the thin portion of the gasket, the height of the battery cap can be suppressed, and the depth of the battery case can be increased accordingly. Since it can be set large, the battery capacity can be increased. That is, the capacity can be increased.

  Since the sealed storage battery according to the present invention employs a metal elastic member, a reliable pressure at which the pressure switch operates normally even when the temperature of the elastic member rises due to heat generation during charging. A sealed storage battery having a switch function can be obtained.

  In the sealed storage battery according to the present invention, the inner peripheral side end portion of the elastic member is brought into contact with the outer peripheral lower end portion of the holding portion of the gasket, or the holding portion of the gasket is formed in an opening formed in the lid. On the other hand, by inserting in a sliding contact state, it is possible to obtain a sealed storage battery in which the contact between the switch plate, which is a terminal constituting the pressure switch, and the lid is good and the operation of contacting and separating the two is reliable.

  In the sealed storage battery according to the present invention, since the lid and the battery cap are joined by welding, the joined state is good and the occurrence of poor joining between the two members can be avoided, whereby the electrical resistance at the joint is reduced. As a result, the charging efficiency is improved. Also, by integrating the base lid and the battery cap in advance by welding, the efficiency of the assembly work can be significantly improved, the assembly accuracy can be improved stably, and foreign matter such as dust and dirt can be removed. Since problems such as intervening on the joint surface can be avoided, high sealing accuracy (sealing performance) can be stably maintained without increasing the electrical resistance. As a result, gas leakage or liquid leakage is less likely to occur, and high charging efficiency can be stably maintained.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a pressure switch built-in sealed storage battery according to a preferred embodiment of the present invention will be described in detail with reference to the drawings.

[Embodiment 1]
FIG. 1 is a longitudinal sectional view of a main part for explaining the configuration of a pressure switch built-in type sealed storage battery according to Embodiment 1, and this pressure switch built-in type sealed storage battery includes an electrode group 10 as shown in the figure. A battery case (negative electrode) 5 in which an alkaline solution (not shown) is housed is sealed with a base lid 2, and a battery cap (positive electrode) is provided on the top surface of the base lid 2 for taking out charging current to the outside. 1) are joined by spot welding or the like, for example. Between the lid 2 and the thin portion 6f of the gasket 6, the switch plate 8 constituting the switch mechanism S for switching the charging current according to the change in the battery internal pressure can be brought into contact with and separated from the lid 2. A disc spring (a resilient member of the present invention) 4 for biasing is provided.

  As apparent from FIG. 1, the switch mechanism S operates when the internal pressure of the battery rises and the thin portion 6f of the gasket bends upward in the drawing. In order for the thin portion 6f of the gasket to bend upward in the drawing, it is necessary to provide at least an interval corresponding to the bending allowance between the lid 2 and the thin portion 6f of the gasket. According to the present invention, as shown in FIG. 1, the space generated by providing a space between the lid 2 and the thin portion 6 f of the gasket is utilized as a storage space for the spring member 4, thereby Compared with the conventional battery in which the cap is disposed in the cap, the height of the battery case is increased by reducing the height of the cap 1 and reducing the height of the cap 1 to reduce the width of the electrode plate 10 (see FIG. Then height) can be increased.

  Further, since the lid 2 and the battery cap 1 are joined by welding, the joining state is ensured and the occurrence of poor joining can be avoided, and the electrical resistance at the joining portion (welded portion of the present invention) 3 is small. Charging efficiency is improved. Further, by integrating the base lid 2 and the battery cap 1 by welding in advance, the efficiency of the assembly work can be remarkably improved, and the assembly accuracy can be stably improved, and dust, dust, etc. It is possible to avoid a problem that foreign matter is present on the joint surface. Therefore, high sealing accuracy (sealing performance) can be stably maintained, and problems such as gas leakage and liquid leakage are less likely to occur.

  The whole will be described in detail. On the upper peripheral edge of the battery case can 5, a concave groove part 5a for tightly fitting the peripheral part of the gasket 6 made of an insulating material is formed. A flange portion 1a formed outwardly at the lower portion of the battery cap 1 formed in the above is disposed at a position inside the inner peripheral portion 6a of the gasket 6, and the flange portion 1a is disposed in a disc-shaped base lid. It is possible to weld on 2 with good workability, for example, by spot welding. A degassing hole h is formed in the side wall surface of the battery cap 1 so that the gasket 6 can be deformed without difficulty according to the change in the internal pressure of the battery.

A locking groove 6b is formed in the inner peripheral portion 6a of the gasket 6, and only the peripheral edge portion of the base lid 2 is locked in the locking groove 6b. Thus, since the engaged only one plate member (Motofuta 2) in the locking groove 6b, formed deep, the container can 5 than when engaged with a conventional two-ply shown in FIG. 7 It is possible to increase the charging capacity (battery capacity). Moreover, since the assembly accuracy is stabilized, it becomes easy to ensure high sealing performance and to maintain the sealing performance.

In the through hole 6d of the cylindrical holding portion 6c formed at the center of the gasket 6, for example, a connection terminal 9 formed in a columnar shape is integrally fitted and fixed, and the lower portion thereof is connected via the lead wire 7. Are connected to the electrode group 10. On the other hand, a disc-shaped switch plate (the other terminal) 8 with a hole is fixed to the upper part of the connection terminal 9 protruding from the through hole 6d . Its on the upper surface of the upper and the switch plate 8 of the connecting terminals 9 can be insulated connection terminal 9 and the switch plate 8 and fitted on the insulating member with respect to the battery cap 1. Name your, instead of the disc spring 4, may be used as the coil spring or a plate spring or the like.

  A circular hole (opening of the present invention) 2a is formed in the central portion of the base lid 2 locked in the locking groove 6b of the gasket 6, and the holding portion 6c of the gasket 6 is inserted into the circular hole 2a with a predetermined gap. Thus, the gasket 6 is freely deformed in accordance with the change in the internal pressure of the battery, and the switch plate 8 is allowed to move in the vertical direction together with the gasket 6. The opening 2a of the present invention is not limited to a circular hole, and may be an ellipse or a square (rectangular, square, etc.).

  In addition, on the upper surface of the gasket 6, a notch-shaped safety valve (notch portion of the present invention) 6 e that facilitates cracking is provided to protect the battery case can 5 when the battery internal pressure suddenly increases. When the internal pressure of the battery suddenly increases during charging, the gasket 6 can be cracked from the safety valve 6e, and the gas can be released to the outside from the small hole h of the battery cap 1. Thus, the battery case can 5 can be prevented from being deformed or damaged, and the safety can be improved.

In this embodiment, the switch mechanism S for switching the charging current is provided between the battery cap 1 and the base lid 2, and the switch mechanism S is a flat plate biased by the disc spring 4. Switch plate (first terminal of the present invention) 8 and a flat plate-shaped cover (second terminal of the present invention) 2. More specifically, the switch plate 8 is fixed to an upper portion of a connection terminal 9 that penetrates the central portion of the gasket 6 and is fixedly provided, and the connection terminal 9 is connected via a deformable lead wire 7. positive electrode current collector plate of the electrode assembly 10 is connected to a (not shown), a part of the upper portion and the switch plate 8 of the connection terminals 9, as described above, thus covered with an insulating member, its outer The outer peripheral edge 8b becomes the first terminal. On the other hand, the inner portion of the base lid 2 is cut out in a circular shape from the welded portion 3, and the peripheral edge (opening edge of the present invention) 2b of the circular hole 2a becomes the second terminal.

  With such a configuration, when the internal pressure of the battery is low, as shown in FIG. 1, the outer peripheral edge 8b of the switch plate 8 comes into contact with the peripheral edge 2b of the base lid 2 and the switch mechanism S is turned on. When the battery internal pressure exceeds a certain pressure, as shown in FIG. 2, the gasket 6 is deformed upward in the figure, so that the outer peripheral edge 8b of the switch plate 8 is separated from the peripheral edge 2b of the base lid 2, and the switch mechanism S is The charging current is cut off and the charging current is cut off, and pulse charging is performed in conjunction with the change in the internal pressure of the battery. In this way, since the charging current is controlled according to the change in the battery internal pressure, an increase in battery temperature can be suppressed, high charging efficiency can be obtained, and rapid charging becomes possible.

  As shown in FIG. 1, the elastic member 4 and the electrode plate 10 are close to each other. If heat is generated in the electrode plate 10, heat is easily transmitted to the elastic member 4, but the disc spring 4 as the elastic member is made of metal. By using a material, the elastic characteristics are more stable than when rubber is used, and it is less affected by the temperature rise. The on / off operation of the mechanism S is stabilized and the reliability is improved.

  In the first embodiment, as shown in FIGS. 1 and 2, one end having a small diameter of the disc spring applied as the resilient member 4 is contacted with the lower end portion of the outer periphery of the cylindrical holding portion 6c provided on the gasket. Make contact. With this configuration, even when the pressure switch shown in FIG. 1 is on, or when the pressure switch is off as shown in FIG. 2, the pressing force of the disc spring against the cylindrical holding portion 6c Since the holding portion 6c is urged without tilting with respect to the lid 2, the contact between the switch plate 8 and the lid 2 is good, the electrical resistance between them is small, and the switch plate 8 and the lid 2 are securely contacted and separated. Therefore, a highly reliable pressure switch function can be obtained.

[Embodiment 2]
In the second embodiment, as shown in FIG. 3, instead of the disc springs apply a conical coil spring as the elastic member 4 at the implementation form 1. In the case of the conical coil spring, unlike the cylindrical coil spring, there is an advantage that the height of the spring can be reduced because the wire constituting the spring does not overlap in the vertical direction.

  In the second embodiment, as shown in FIG. 3, one end having a small diameter of the conical coil spring is brought into contact with the lower end portion of the outer periphery of the cylindrical holding portion 6c provided on the gasket. With this configuration, the holding portion 6c is biased with respect to the lid 2 by the pressing force of the coil spring against the cylindrical holding portion 6c, so that the contact between the switch plate 8 and the lid 2 is good, and the electrical Since the resistance is small and the switch plate 8 and the lid 2 are reliably connected and separated, a highly reliable pressure switch function can be obtained.

[Embodiment 3]
In the third embodiment, as shown in FIG. 4, the cylindrical holding portion 6 d formed at the center portion of the gasket 6 is brought into sliding contact with the opening 2 a formed in the base lid 2. The outer peripheral edge 8b of the switch plate 8 can be brought into contact with the peripheral edge 2b of the lid 2 in a parallel state. In addition, the same code | symbol is attached | subjected about the same or equivalent member as Embodiment 1, and the description is abbreviate | omitted.

  For example, if the outer diameter of the holding portion 6d and the inner diameter of the opening 2a are set under a design condition that can ensure the sealing performance between the holding portion 6d and the opening 2a, the sealing performance is improved and gas leakage or liquid leakage is improved. In addition, since the displacement operation in the vertical direction of the holding portion 6d that holds the connection terminal 9 is stabilized, the contact state of the switch plate 8 with respect to the base lid 2 is ensured and high. Charge efficiency can be obtained stably.

  In the third embodiment, the state in which the battery internal pressure is increased is basically the same as the state in FIG. 2 and is not shown. Further, the opening 2a of the present invention is not limited to a circular hole, but may be an ellipse or a square (rectangular, square, etc.), as in the first embodiment.

(Example)
A nickel electrode having a width of 45.5 mm was used as a positive electrode, and a hydrogen storage alloy electrode having a width of 45.5 mm was wound through a separator to constitute an electrode plate group. Applying the polar plate group, the configuration shown in FIG. 1 (caps 1 are joined by welding the lid 2, Motofuta 2 Nomigakakari is sealed to the locking groove 6b of the gasket 6) comprises a operation Ten thousand sealed AA-size sealed nickel-metal hydride storage batteries with a rated capacity of 1800 mAh and a built-in pressure switch (S) having a pressure of 2.4 MPa were produced. The configuration shown in FIG. 1 makes it possible to reduce the height of the cap and the pressure switch and increase the width of the electrode by 2.5 mm compared to the conventional storage battery described as a comparative example described later. The capacity could be increased by about 6% compared to the conventional storage battery.

  All the produced batteries were left in a normal temperature and humidity atmosphere for one week, and then a visual appearance inspection was performed to investigate the presence of liquid leakage and assembly failure. After removing 20 sample batteries from a storage battery that has been judged to be normal by visual inspection (a storage battery that has not been leaked and has been assembled normally) and formed by a predetermined method, Charge for 16 hours at a temperature of 20 ° C. and a charge rate of 0.1 ItA, leave for 1 hour at the same temperature, and then discharge at a discharge rate of 0.2 ItA and a discharge cut voltage of 1.0 V to obtain a discharge capacity equal to the rated capacity. It was confirmed. Next, constant voltage charging was performed for 15 minutes at an ambient temperature of 20 ° C. and a charging voltage of 1.65 V. After standing at the same temperature for 1 hour, constant current discharging was performed at a discharge rate of 0.2 ItA and a discharge cut voltage of 1.0 V. This charge / discharge operation was repeated 5 times, and the ratio of the discharge capacity obtained by the fifth discharge to the rated capacity was used as an index for evaluating the charge acceptance performance in the rapid charge.

(Comparative example)
A nickel electrode having a width of 43 mm was used as a positive electrode, a hydrogen storage alloy electrode having a width of 43 mm was laminated via a separator, and the laminate was wound to form a wound electrode group. Applying the electrode plate group, the structure shown in FIG. 7 (with the elastic member 4 made of rubber inside the cap 21, the cap 21 is not welded to the lid 22, Other than the above, the other configuration is the same as that of the above embodiment, and a built-in AA size pressure switch with a rated capacity of 1700 mAh. 10000 sealed storage batteries were produced. The batteries were allowed to stand at room temperature and humidity for 1 week in the same manner as in the Examples, and the presence / absence of leakage and assembly failure were examined by visual inspection of all the batteries. In addition, 10 batteries determined to be normal in visual appearance inspection were taken out and subjected to the same test as in the example.

即ち、実施例の密閉型ニッケル水素蓄蓄電池においては、漏液のあった電池数、及び、不具合蓋のあった電池数も０であった。これに対して、比較例の密閉型ニッケル水素蓄蓄電池では、漏液のあった電池数は１０個、蓋の組み付けに不具合が認められた電池数は７個存在した。これは、比較例の密閉型ニッケル水素蓄蓄電池では、キャップ２１と蓋２２が溶接されていないため、予め、これらを組み付けることができず、そのために、組付け不良による位置ずれや接合面への異物の介入等が発生し、封口精度にばらつきが発生したためである。 (Visual appearance survey results)
Table 1 shows the results of visual inspection of the examples and comparative examples.

That is, in the sealed nickel-metal hydride storage battery of the example, the number of batteries that had leaked and the number of batteries that had a defective lid were also zero. On the other hand, in the sealed nickel-metal hydride storage battery of the comparative example, there were 10 batteries that had leaked liquid and 7 batteries that had a defect in the assembly of the lid. This is because in the sealed nickel-metal hydride storage battery of the comparative example, since the cap 21 and the lid 22 are not welded, they cannot be assembled in advance. This is because there was a variation in sealing accuracy due to the intervention of foreign substances.

(Quick charge test results)
FIG. 5 shows the result of the quick charge test performed by the above charging. In FIG. 5, the horizontal axis represents the fifth discharge capacity {ratio to the rated capacity (%)}, and the vertical axis represents the number of batteries. As shown in FIG. 5, the sealed storage battery of the comparative example has a considerably lower discharge capacity than the sealed storage battery of the example, and the discharge capacity of 2 cells out of 10 cells is extremely low. It was confirmed that The reason why the discharge capacity of the comparative example battery is generally lower than that of the example battery is that the cap and the lid are not joined, and therefore the contact resistance between them is large and the charge acceptance during rapid charging is low. The reason why the discharge capacity of 2 pieces is extremely low is that the contact resistance between the cap and the lid becomes extremely large because the assembling accuracy of the cap and the lid has a minor problem that cannot be confirmed by visual inspection. It is thought that it was because of.

  FIG. 6 shows an example of the temporal transition of the charging current and the battery temperature when the sealed nickel-metal hydride storage battery according to the embodiment is charged at a constant voltage. As shown in FIG. 6, the pressure switch is operated in the steel plate for charging, and pulse charging is performed while the pressure switch is operating, and further increase in battery temperature is suppressed. In the charging at the ambient temperature of 20 ° C. shown here, the pressure switch operated normally also in the comparative battery. However, for example, when charging at a high temperature such that the ambient temperature exceeds 30 ° C., the battery temperature further increases. For this reason, the elasticity of the rubber deteriorates, the pressure switch does not operate normally, the pressure switch remains on, and the battery temperature may rise abnormally.

It is sectional drawing which shows the structure of the pressure switch built-in type sealed storage battery which concerns on Embodiment 1 of this invention. It is sectional drawing of a pressure switch built-in type sealed storage battery in a state where the internal pressure of the battery is increased. It is sectional drawing which shows the structure of the pressure switch built-in type sealed storage battery which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the structure of the pressure switch built-in type sealed storage battery which concerns on Embodiment 3 of this invention. It is a comparison figure of the discharge capacity of the Example and a comparative example. It is explanatory drawing which shows the charge characteristic of the comparative example of the Example. It is sectional drawing which shows an example of a structure of the conventional pressure switch built-in type sealed storage battery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Battery cap, 1a ... Outward flange, 2 ... Elementary lid, 2b ... Opening edge, 3 ... Welding part, 4 ... Elastic member, 5 ... Battery case can, 6 ... Gasket, 6a ... Inner peripheral part, 6b ... Locking groove, 6c ... holding portion, 6e ... notch portion, 6f ... thin portion, 8 ... switch plate, 8b ... outer peripheral edge, 9 ... connection terminal, 10 ... electrode group, S ... switch mechanism, S1 ... first terminal , S2 ... second terminal, h ... small hole

Claims (2)

The battery case (5) containing the electrode group (10) together with the alkaline solution is a metal lid (2)
The cap (1) serving as a positive electrode terminal or a negative electrode terminal is mounted on the lid (2) by sealing the gasket (6) and the connection terminal (9) fitted in the through hole (6d) of the gasket (6). In the sealed storage battery, the charging member (4), wherein the charging current is cut off by a switch mechanism (S) provided with a resilient member that expands and contracts in response to a change in the internal pressure of the battery. Is disposed between the inner surface of the lid (2) and the thin part (6f) of the gasket (6), the switch plate fixed to the upper part of the connection terminal (9), and the lid (2). Are in contact with each other, and when the internal pressure of the battery exceeds a certain level, the elastic member contracts and the gasket (6) is deformed to separate the switch plate and the lid (2). A sealed storage battery characterized by that .   The sealed storage battery according to claim 1, wherein the elastic member (4) is made of a metal material.

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