JP2010257625A - Bypass switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bypass switch capable of activating a closed circuit operation promptly even at the time of battery cell over discharge. <P>SOLUTION: A bypass switch is equipped with a first and a second fixed electrodes as a pair of electrodes connected in parallel to cells of the battery, a shaft which can be displaced in a perpendicular direction to the fixed electrodes, a movable electrode which short-circuits the cell through direct electrical connection to the fixed electrodes by being pressed in a perpendicular direction when the shaft is displaced, and a thermally actuating device, energized by the shaft, and provided with a heat-generating semiconductor element sandwiched by heat insulating members, and solder. The heat actuating device is connected to the fixed electrodes. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a bypass switch having a function of short-circuiting a cell that is in a high resistance state or an open circuit state due to a failure in a storage battery to which a plurality of cells are connected.

  In a storage battery in which a plurality of cells are connected in series, in the case of a failure in which one cell is in a high resistance state or an open circuit state, the entire storage battery becomes unusable.

  As a countermeasure in the case of a failure such as a high resistance state or an open circuit state, a thermal switch is connected in parallel to each cell, and a bypass switch is provided that short-circuits the failed cell using heat generated by the thermal switch in the event of a failure. The bypass switch is preferably lightweight and does not dissipate a large amount of power when the stored current is applied.

  2. Description of the Related Art Conventionally, there has been known a bypass switch including a movable electrode that is displaced in a vertical direction with respect to a pair of fixed electrodes by a pressing force of a pressurizing device, and a thermal actuator that receives the pressing force applied to the movable electrode through a shaft. It has been. In this bypass switch, a parallel circuit is formed of a switch portion including a pair of fixed electrodes and a movable electrode, and a thermal actuator having a diode and solder. When the cell malfunctions, the solder melts due to the heat generated by the forward current in the diode, and the thermal actuator is displaced by the applied pressure of the pressurizing device, and the fixed electrode of the switch unit is electrically connected by the movable electrode. By doing so, the abnormal cell is short-circuited and bypassed (for example, see Patent Document 1).

Japanese Patent Laying-Open No. 2006-252804 (pages 4-5, FIG. 1)

  The diode which is a component of the thermal actuator of Patent Document 1 has a configuration in which two diodes are arranged in series, that is, have a redundant configuration, so that even if one of them has a short-circuit fault, a short-circuit current does not flow through the cell. .

  In a storage battery, it is desired that the bypass switch operates even when the cell polarity is reversed at the time of cell overdischarge and the cell falls into a semi-failure state. However, in the configuration of the thermal operation device as disclosed in Patent Document 1, since the voltage drop of the diode is large, no current flows to the diode side, and the bypass switch does not operate.

  Even if a current flows through the diode, the discharge current value at the time of overdischarge is small, the amount of heat generated by the diode is small, and it is assumed that the solder does not reach the melting point.

  In such a case, when the cell is overdischarged, the overdischarge state continues without operating the bypass switch, and the cell that is in a semi-failure state changes to a resistor, maintaining a high heat generation state. There was a problem of deterioration.

  The present invention solves the above-described problems, and an object of the present invention is to provide a bypass switch that can quickly perform a closing operation even during overdischarge.

  The bypass switch according to the present invention includes a pair of first and second fixed electrodes connected in parallel to each of the battery cells connected in series and arranged with a gap therebetween, and the pair of first electrodes A shaft displaceable in a vertical direction with respect to the first and second fixed electrodes, and a predetermined gap in the vertical direction with respect to each of the pair of first and second fixed electrodes, and the shaft is displaced A movable electrode that is pressurized in the vertical direction by a pressure device and electrically connected to the fixed electrode to short-circuit the cell, a first heat insulating member biased by the shaft, and a second A first connection for connecting the heat-insulating member, one exothermic semiconductor element and solder sandwiched between the first and second heat-insulating members, and the first fixed conductor and one end side of the semiconductor element. Other than the conductor, the second fixed conductor, and the semiconductor element And a second connecting conductor connecting the side, a, is obtained and a thermally actuated device to displace the shaft in the vertical direction by the heat generation of the semiconductor element.

  According to the bypass switch of the present invention, even when a battery cell is overdischarged and a half-failure state occurs, it is possible to provide a bypass path that operates the bypass switch and bypasses the half-failure cell. is there. Further, when a short circuit failure occurs in the diode, the fuse function of the bypass switch works, and the failed bypass switch can be disconnected from the storage battery cell.

It is a block diagram which shows the cross section of the bypass switch which concerns on Embodiment 1 of this invention. It is a figure which shows the circuit structure when the bypass switch which concerns on Embodiment 1 of this invention is connected in parallel with the cell 9 of the storage battery. It is a figure which shows the structure of the thermal actuator which concerns on Embodiment 1 of this invention.

Embodiment 1 FIG.
1 is a cross-sectional view showing a configuration of a bypass switch according to Embodiment 1 of the present invention. 1, the bypass switch according to the first embodiment includes a chassis 1 made of an insulating material and provided with a housing space, a pair of fixed electrodes 2 and 3 constituting first and second fixed electrodes, and a movable electrode. 4, a shaft 5 made of an insulating material, a pressurizing device 6 provided at the uppermost part in the housing space of the chassis 1, and a thermal operation device 7 provided at the lower part in the housing space of the chassis 1. Composed.

  The fixed electrodes 2 and 3 are made of a pair of conductors fixed so as to protrude into the housing space of the chassis 1 with a gap therebetween. The fixed electrodes 2 and 3 are arranged so that the inclined end faces face each other, so that both end faces form a V-shaped groove. The movable electrode 4 is located between the opposed inclined end faces of the fixed electrodes 2 and 3, and is arranged with a predetermined gap from the fixed electrodes 2 and 3 in the upper part in the housing space of the chassis 1. The movable electrode 4 has an inclined surface arranged in a V shape in which two opposing surfaces form an acute angle. The movable electrode 4 is movable downward with respect to the fixed electrodes 2 and 3 in the vertical direction of FIG. That is, in normal times, the inclined surfaces facing the movable electrode 4 and the inclined end surfaces facing the fixed electrodes 2 and 3 face each other with a predetermined gap in the vertical direction. At the time of movement, each inclined surface of the movable electrode 4 moves to a position in contact with each inclined end surface of the fixed electrodes 2, 3, and the inclined surface of the movable electrode 4 is formed by the inclined end surfaces of the fixed electrodes 2, 3. To fit. Thereby, the fixed electrodes 2 and 3 and the movable electrode 4 constitute a switch part of the bypass switch. The movable electrode 4 has a U-shaped groove positioned between two inclined surfaces at the lower end, and the upper end portion of the shaft 5 forming an arc is fitted into the U-shaped groove. Yes. The lower end portion of the shaft 5 is connected to the upper end portion of the thermal actuator 7. The shaft 5 passes through a groove that communicates between an upper portion and a lower portion of the housing space of the chassis 1.

  The pressurizing device 6 is constituted by an elastic member such as a coil spring. The pressurizing device 6 biases the movable electrode 4 and the shaft 5 by elastic force, and pressurizes the movable electrode 4 and the shaft 5 downward in the vertical direction in FIG. In normal times, the pressurizing device 6 presses the shaft 5 against the thermal actuator 7. When the thermal actuator 7 is actuated and the upper end position of the thermal actuator 7 is lowered due to the contraction, the shaft 5 is moved downward in FIG. By making line contact with the fixed electrodes 2 and 3, the fixed electrodes 2 and 3 are conducted through the movable electrode 4, and the switch unit is activated.

  FIG. 2 is a diagram showing the configuration of the thermal actuator 7. The thermal actuator 7 includes a laminated body in which a first heat insulating spacer 8 made of a heat insulating member, a diode 9, a metal plate 10, a solder 11, and a second heat insulating spacer 12 made of a heat insulating member are stacked. Is done. A first connecting conductor 13 is sandwiched between the first heat insulating spacer 8 and the diode 9. A second connection conductor 14, which is a high resistance connection conductor, is sandwiched between the solder 11 and the second heat insulating spacer 12. The diode 9 constitutes a semiconductor element that generates heat when a current flows. In addition, the stacked body of the diode 9, the metal plate 10, and the solder 11 is disposed between one end of the first heat insulating spacer 8 and one end of the second heat insulating spacer 12. The metal plate 10 is made of a conductive metal having high thermal conductivity, and adjusts the overall height of the thermal actuator 7 (the height in the vertical direction in FIG. 2). The other end of the first heat insulating spacer 8 is in contact with the lower end of the shaft 5. The other end of the second heat insulating spacer 12 is fixed in contact with the chassis 1.

  The first connection conductor 13 electrically connects the fixed electrode 2 and the diode 9, and the second connection conductor 14 electrically connects the solder 11 and the fixed electrode 3. The thermal actuator 7 is pressurized by the pressurizing device 6 via the movable conductor 4 and the shaft 5, so that electrical continuity between the fixed electrode 2 and the fixed electrode 3 is maintained. .

  In the first embodiment, the first connection conductor 13 and the second connection conductor 14 are ribbon conductors having a small cross-sectional area, a long conductor length, and flexibility. Further, only the second connection conductor 14 is made of a metal having a large internal thermal resistance. For this reason, since heat dissipation from the first connecting conductor 13 and the second connecting conductor 14 can be reduced, most of the heat generated from the diode 9 is between the first heat insulating spacer 8 and the second heat insulating spacer 12. Conducted to the solder 11 sandwiched between the two.

  FIG. 3 is a circuit diagram showing a configuration in which the bypass switch of Embodiment 1 is connected in parallel to the storage battery cell. In FIG. 3, a parallel circuit is configured from the heat operating device 7 and the switch unit configured by the fixed electrodes 2 and 3 and the movable conductor 4, and the parallel circuit is connected in parallel to each storage battery cell 100. A bypass switch is configured. This parallel circuit has a fuse function. In FIG. 3, one bypass switch is connected to one storage battery cell 100, but actually, a bypass switch is connected to each of the storage battery cells 100 connected in series.

Next, the operation of the bypass switch according to the first embodiment will be described.
According to the configuration of the circuit diagram shown in FIG. 3, when the cell 100 is in a normal state, a reverse voltage is applied to the diode 9 so that no current flows and the bypass switch does not operate. However, if the cell 9 fails and becomes in a high resistance state or an open circuit state, a forward current flows through the diode 8 and heat is generated.

  When the diode 8 generates heat, this heat is transmitted to the solder 11 through the metal plate 10 in the thermal actuator 7 and melts the solder 11. When the solder 11 is melted, the shaft 5 can be moved downward. At this time, the pressurizing device 6 pressurizes the movable electrode 4 to push the shaft 5 downward in FIG. 1 so that the movable electrode 4 moves toward the fixed electrodes 2 and 3 as the shaft 5 moves downward. Move to. Thereby, the movable electrode 4 and the fixed electrodes 2 and 3 come into contact with each other, the fixed electrodes 2 and 3 are electrically connected by the movable electrode 4, and a bypass circuit for short-circuiting between the abnormal cells 100 is formed.

  Next, when the cell is over-discharged, the cell polarity is reversed and a semi-failure state occurs. However, when the plurality of diodes 9 presented in Patent Document 1 are arranged in series, the voltage drop due to the diode 8 becomes large, and no current flows to the diode side, so the bypass switch does not operate. On the other hand, in the bypass switch of the first embodiment, the diode 9 is arranged by one, the voltage drop of the diode is reduced, the discharge current flows through the diode at the time of cell polarity inversion, the thermal operation device is activated, A bypass circuit is formed.

  In addition, by using one diode 9, the amount of heat generated by the diode 9 is smaller than when a plurality of diodes 9 disclosed in Patent Document 1 are arranged. Therefore, in the bypass switch according to the first embodiment, the first heat insulating spacer 8 is disposed between the diode 9 and the shaft 5, and the second heat insulating spacer 12 is disposed between the solder 11 and the chassis 1. By providing the first heat insulating spacer 8 and the second heat insulating spacer 12, the amount of heat generated by the diode 9 in the direction of the shaft 5 and the chassis 1 can be reduced. As a result, the bypass switch according to the first embodiment can transmit heat generated by the diode 9 to the solder 11 more efficiently than the arrangement disclosed in Patent Document 1, and is necessary and sufficient to reach the solder 11 to the melting point. It is possible to give a large amount of heat. That is, by disposing the heat insulating spacer in the heat transfer path portion other than the heat transfer path between the diode 9 and the solder 11, the heat generated by the diode 9 can be efficiently contributed to the melting of the solder.

  Furthermore, if the arrangement is such that one diode 9 is connected in parallel to the cell, when the diode 9 is short-circuited, the cell to which the diode is connected in parallel also causes a short-circuit event, resulting in a cell failure. In this embodiment, by using a high-resistance connection conductor in which the cross-sectional area of the second connection conductor 14 is adjusted to a predetermined size or less, the second connection conductor 14 has a fuse function, and the diode 9 At the time of a short-circuit failure, the second connecting conductor 14 is broken by a short-circuit current, thereby preventing a cell short-circuit event due to a short-circuit failure of the diode 9.

  Instead of the second connection conductor 14, a high resistance connection conductor whose cross-sectional area is adjusted to a predetermined size or less may be used for the first connection conductor 13. That is, by providing a fuse function to the energization path in the bypass switch, it is possible to disconnect the bypass switch from the cell by cutting the fuse when a diode short-circuit failure occurs.

  As described above, the bypass switch according to Embodiment 1 is connected in parallel to each of the battery cells connected in series in the bypass switch connected in parallel to each of the battery cells connected in series. A pair of first and second fixed electrodes that are connected and arranged with a gap therebetween, a shaft that is vertically displaceable with respect to the pair of first and second fixed electrodes, and the pair of The first and second fixed electrodes are arranged with a predetermined gap in the vertical direction, and when the shaft is displaced, the pressure is applied in the vertical direction by a pressurizing device. A movable electrode that is electrically connected and short-circuits the cell, a first heat insulating member that is biased with one end abutting against the shaft, and a first fixed member that is in contact with the other end of the first heat insulating member A first connecting conductor connected to the conductor; , One semiconductor element in which one terminal is in contact with the first connecting conductor, solder disposed on the other terminal side of the semiconductor element and melted by heat generation of the semiconductor element, and the other terminal side of the semiconductor element And a second heat insulating member disposed in contact with the high resistance connection conductor, and the shaft is displaced in the vertical direction by melting the solder. And a heat operating device.

  As a result, a bypass switch can be obtained in which the closing operation is performed quickly even when the battery cell is over-discharged. Therefore, the satellite battery, the mobile battery, etc. are highly reliable for cell failure, and are small and lightweight. Can be effectively used as a bypass switch. In addition, even when a storage battery cell is overdischarged and a semi-failure state occurs, a bypass switch can be activated to provide a bypass path that bypasses the semi-failure state cell. Further, when a short circuit failure occurs in the diode, the fuse function of the bypass switch works, and the failed bypass switch can be disconnected from the storage battery cell.

  DESCRIPTION OF SYMBOLS 1 Chassis, 2 (1st) fixed electrode, 3 (2nd) fixed electrode, 4 Movable electrode, 5 Shaft, 6 Pressurization apparatus, 7 Thermal actuator, 8 1st heat insulation spacer, 9 Diode (semiconductor element) ) 10 metal plate, 11 solder, 12 second heat insulating spacer, 13 first connecting conductor, 14 second connecting conductor, 100 cells.

Claims (2)

A pair of first and second fixed electrodes connected in parallel to each of the cells of the battery connected in series and arranged with a gap between each other;
A shaft displaceable in a direction perpendicular to the pair of first and second fixed electrodes;
The fixed electrode is disposed in the vertical direction with a predetermined gap with respect to each of the pair of first and second fixed electrodes, and is pressurized in the vertical direction by a pressure device when the shaft is displaced. A movable electrode that is electrically connected to and short-circuits the cell;
A first heat insulating member biased by the shaft; a second heat insulating member; one exothermic semiconductor element and solder sandwiched between the first and second heat insulating members; and the first fixing. A first connection conductor that connects a conductor and one end side of the semiconductor element; and a second connection conductor that connects the second fixed conductor and the other end side of the semiconductor element; A thermal actuator for displacing the shaft in the vertical direction by heat generation of
Bypass switch with   The bypass switch according to claim 1, wherein the first or second connection conductor is broken by a short-circuit current.

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