JP4358134B2 - Bypass switch - Google Patents

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, and particularly relates to a bypass switch that responds to a current. It is.

  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 for a failure in which one cell is in a high resistance state or an open circuit state, a diode is connected in parallel to each cell, and a bypass switch is provided that short-circuits the failure cell using the heat generated by the diode at the time of failure as a trigger. The bypass switch is preferably lightweight and does not dissipate a large amount of power when the stored current is applied.

  In Patent Document 1, a hole is provided in the movable contact in order to maintain a predetermined gap between the movable contact and the fixed contact as an open circuit, and the hole of the movable contact is pinned to the hole of the fixed portion. A bypass switch is disclosed that closes the switch contact by holding and conducting the heat of the diode from the heat conduction base to the shape memory metal rod in the event of failure, extending the shape memory metal rod and pushing the movable contact to shear the pin ing.

JP-A-7-2013365 (page 3-6, FIGS. 1 to 3)

  In the bypass switch as disclosed in the above-mentioned Patent Document 1, since the contact is pressed by the extension of the shape memory metal rod, the shape is more than the distance necessary for the movable contact to contact the fixed contact. The amount of change (elongation) of the memory metal rod is required, the total length of the shape memory metal rod is increased, and the heat conduction base is also increased. As a result, the heat capacity of the heat conduction base and the shape memory metal rod is increased.

  For this reason, it took time to heat the shape memory metal rod, and there was a problem that a quick closing operation could not be performed.

  In addition, since the hole of the movable contact is held by the pin in the hole of the fixed part to always open the circuit, there is a problem that malfunction is likely to occur when used under conditions where vibration or impact is applied. there were.

  An object of the present invention is to provide a bypass switch that solves the above-described problems and that is quick to perform a closing operation and is less likely to malfunction even under a situation where vibration or impact is applied. .

The bypass switch according to the present invention includes a fixed conductor composed of a pair of fixed conductors, and a pair of the fixed conductors arranged between the pair of fixed conductors with a predetermined gap in a direction perpendicular to the pair of fixed conductors. In a bypass switch including a switch unit having a movable conductor made of a conductor that is driven in a vertical direction to connect between the fixed conductors,
A pressurizing device that pressurizes the movable conductor in a direction perpendicular to the pair of fixed conductors;
A semiconductor element that generates heat when energized and receives a pressure applied to the movable conductor, a first metal plate in contact with the semiconductor element, solder in contact with the first metal plate, and a first sandwiching the solder together with the first metal plate A thermal actuator in which two metal plates are stacked in a direction in which the pressure device pressurizes;
A conductor that electrically connects the switch unit and the thermal actuator in parallel to form a parallel circuit;
The parallel circuit is connected in parallel with each of a plurality of cells connected in series of storage batteries, and the cells are connected in parallel so that the semiconductor element is not energized at all times, and the semiconductor element is energized at the time of abnormality. Then, the solder is melted by the heat generated by the semiconductor element, the thermal actuator is displaced by the pressure applied by the pressurizing device, and the movable conductor is displaced vertically in the direction of the fixed conductor. The pair of fixed conductors are electrically connected by the movable conductor to form a bypass circuit that short-circuits the abnormal cell.

  According to the bypass switch according to the present invention, an abnormal cell bypass operation can be performed quickly when the storage battery cell is abnormal, and an effect is also obtained that malfunction is less likely to occur even when vibration or shock occurs when the contact is kept open. .

Embodiment 1 FIG.
FIG. 1 is a sectional view showing Embodiment 1 of a bypass switch according to the present invention. As shown in FIG. 1, the bypass switch according to the first embodiment includes a case 1 made of an insulating material, fixed conductors 21 and 22 made of a pair of conductors fixed to the case 1, and fixed conductors 21 and 22. The movable conductor 23 is a conductor which is arranged with a predetermined gap in a direction perpendicular to the fixed conductors 21 and 22 and is connected to the fixed conductors 21 and 22 by being driven in a direction perpendicular to the fixed conductors 21 and 22. The switch part which has is provided. In addition, a shaft 51 integral with the movable conductor 23, a thermal actuator 10 described later, and a pressurizing device 11 configured by a coil spring or the like that pressurizes the movable conductor 23 and the shaft 51 in a direction perpendicular to the fixed conductors 21, 22 ing. In addition, a conductor 31 that connects the fixed conductor 21 and one end of the thermal actuator 10, and a conductor 32 that connects the fixed conductor 22 and the other end of the thermal actuator 10, the thermal actuator 10 and the switch unit are arranged in parallel. A connected parallel circuit is formed. Here, a ribbon conductor having a small cross-sectional area and a long conductor length is used for the conductors 31 and 32.

  The thermal actuator 10 is provided with a diode 41 and a diode 42 as semiconductor elements that generate heat when a current flows. The thermal actuator 10 includes a diode 41 and a diode 42, a diode check terminal 33 between the diode 41 and the diode 42, a (first) metal plate 43 connected to the diode 42, a (second) metal plate 44, A solder 45 sandwiched between the metal plates 43 and 44 is provided, and the diode 41, the diode 42, the metal plate 43, the metal plate 44, and the solder 45 are stacked in the pressing direction of the pressing device 11. The thermal actuator 10 is pressurized by a shaft 51 that receives the pressure applied by the pressure device 11.

  FIG. 2 is a circuit diagram in which the bypass switch of the first embodiment is connected in parallel with the storage battery cell. As shown in FIG. 2, a parallel circuit of the thermal actuator 10 and the switch unit is connected in parallel with the cell 100. In FIG. 2, a parallel circuit is connected to one cell 100, but actually a parallel circuit is connected to each of the cells 100 connected in series. Further, the diode check terminal 33 between the diodes 41 and 42 is flexible, and it is confirmed that the diode 41 is functioning normally by measuring the voltage between the fixed conductor 21 and the diode check terminal 33. It is possible to confirm that the diode 42 is functioning normally by measuring the voltage between the fixed conductor 22 and the diode check terminal 33.

  According to the configuration of the circuit diagram shown in FIG. 2, when the cell 100 is in a normal state, a reverse voltage is applied to the diodes 41 and 42 so that no current flows and the bypass switch does not operate. However, when the cell 100 fails and becomes in a high resistance state or an open circuit state, a forward current flows through the diodes 41 and 42 and heat is generated.

  When the diodes 41 and 42 generate heat, the heat is conducted through the metal plate 43 and the solder 45 is heated and melted. When the solder 45 is melted, the metal plate 43, the diodes 41 and 42, the shaft 51, and the movable conductor 23 are pushed by the pressing device 11 and moved downward in the stacking direction, and the movable conductor 23 and the fixed conductors 21 and 22 are moved. The bypass conductor is formed in which the fixed conductor 21 and the fixed conductor 22 are electrically connected to each other by the movable conductor 23 to short-circuit between the abnormal cells 100.

  According to the first embodiment, when the thin solder 45 having a thickness exceeding the gap between the fixed conductors 21 and 22 and the movable conductor 23 is melted, the movable conductor 23 is displaced in the vertical direction, and the fixed conductors 21 and 22 are fixed. And the movable conductor 23 are in contact with each other, and the bypass switch is operated. Therefore, the bypass switch can be operated quickly, and a small and lightweight bypass switch can be obtained.

  Further, by using a ribbon conductor having flexibility as the conductor 31, the conduction state to the thermal actuator 10 is not cut when the thermal actuator 10 is displaced in the vertical direction as the solder 45 melts. It is possible to prevent the diodes 41 and 42 and the metal plate 43 from being displaced in the vertical direction when the solder 45 is melted.

  In addition, since the ribbon conductor is used for the conductors 31 and 32, the cross-sectional area of the ribbon conductor is small. Therefore, the amount of heat generated by the diodes 41 and 42 from the conductors 31 and 32 to the outside of the thermal actuator 10 is extremely small. It is possible to prevent the heating efficiency from being lowered.

  Further, since the case 1 is made of an insulating material having a low thermal conductivity, the amount of heat from the thermal actuator 10 escaping to the outside of the case 1 is extremely small, and the heating efficiency for heating the solder 45 is improved. Well, after the failure of the cell 100, the solder 45 melts quickly and the bypass switch operates quickly.

  For the fixed conductors 21 and 22 and the movable conductor 23, it is preferable to use copper or a copper alloy having good electrical conductivity.

  Further, in the configuration of FIG. 1, the fixed conductors 21 and 22 and the movable conductor 23 are in direct contact with each other, but another copper alloy is used as a contact at the contact portion between the fixed conductors 21 and 22 and the movable conductor 23. By attaching and using it by brazing etc., the usage-amount of an expensive copper alloy can be reduced.

  Moreover, although the example which used the two diodes 41 and 42 was shown, more diodes (3 or more) may be used, and a bypass switch operates more rapidly by increasing the number of diodes. become.

  Further, the thickness of the solder 45 may be larger than the vertical gap dimension between the movable conductor 23 and the fixed conductors 21 and 22. For example, the vertical gap dimension between the movable conductor 23 and the fixed conductors 21 and 22 is set. If the thickness is set to 2 mm, the thickness of the solder 45 may be set to a value exceeding 2 mm, for example, 3 mm.

Embodiment 2. FIG.
FIG. 3 is a sectional view showing Embodiment 2 of the bypass switch according to the present invention. In the first embodiment (FIG. 1), the diodes 41 and 42 of the thermal actuator 10 are arranged on the metal plate 43 side. However, as shown in FIG. 10 diodes 41 and 42 are arranged so as to sandwich the metal plates 43 and 44 from both outsides.

  According to the configuration of the second embodiment, since the solder 45 and the metal plates 43 and 44 are sandwiched between the diodes 41 and 42 which are heat generation sources, heat is generated from both sides of the metal plates 43 and 44. Accordingly, the solder 45 can be melted more rapidly than in the first embodiment.

  In addition, since the solder 45 is sandwiched between the metal plates 43 and 44 heated by the diodes 41 and 42, the solder 45 is sufficiently attached by the heat capacity of the metal plates 43 and 44 even when no current flows through the thermal actuator 10. Can be melted. The size of the metal plates 43 and 44 is the sum of the two, and the heat capacity is equivalent if the metal plates 43 and 44 are the same as the metal plate 43 shown in FIG. 1, so the thickness of the metal plate 44 in the case of FIG. Accordingly, the vertical height of the thermal actuator 10 can be reduced.

  In addition, when the diode check terminal 33 is disposed between the metal plate 44 and the diode 42 as in the configuration of the thermal actuator 10 illustrated in FIG. 3, the diode check terminal 33 needs to have flexibility. Absent.

Embodiment 3 FIG.
In the third embodiment, the heat capacity of the metal plate 43 in contact with the diode 42 in the first embodiment or the metal plates 43 and 44 in contact with the diodes 41 and 42 in the second embodiment is greater than the heat capacity of the solder 45. The volume is also large. At the moment when the thermal actuator 10 is activated and the movable conductor 23 comes into contact with the fixed conductors 21 and 22, the current flowing in the thermal actuator 10 starts to flow from the movable conductor 23 to the fixed conductors 21 and 22. Since 42 does not generate heat, the solder 45 is not sufficiently melted, and the movable conductor 23 may not be sufficiently displaced by the pressure device 11.

  According to the configuration of the third embodiment, even when no current flows through the thermal actuator 10 and the diodes 41 and 42 do not generate heat, the metal plates 43 and 44 have sufficient heat capacity. Even immediately after contact with the fixed conductors 21 and 22, the solder 45 can be melted, and the pressing device 11 can sufficiently displace the movable conductor 23. As a result, the contact resistance between the movable conductor 23 and the fixed conductors 21 and 22 can be reduced, so that power loss in the bypass switch can be minimized.

Embodiment 4 FIG.
In the fourth embodiment, a groove is provided on the surface of the metal plates 43 and 44 of the first and second embodiments that come into contact with the solder 45.

  According to the configuration of the fourth embodiment, since the solder can flow into the groove when the solder 45 is melted, the melted solder 45 does not hinder the displacement of the movable conductor 23, and the movable conductor 23 and the fixed conductor 21 and 22 can come into contact with each other quickly and with a small contact resistance.

  Further, due to the capillary action of the grooves provided in the metal plates 43 and 44, the molten solder flows into the grooves, and a new surface of the unmelted solder 45 comes into contact with the metal plates 43 and 44 one after another. As a result, the effect of faster melting of the solder 45 can be obtained. When both the metal plates 43 and 44 are heated, the same effect can be obtained even if the grooves are provided only on one side instead of both the metal plates 43 and 44.

Embodiment 5 FIG.
In the fifth embodiment, Sn / Ag lead-free solder is used as the solder 45 used in the first to fourth embodiments.

  Since the solder 45 is constantly pressurized by the pressurizing device 11, there is a possibility that the bypass switch malfunctions due to the creep of the solder 45, but according to the fifth embodiment, the solder 45 has a good creep strength. Since Sn / Ag-based lead-free solder is used, a malfunction of the bypass switch due to the creep of the solder 45 does not occur.

  The bypass switch according to the present invention can be effectively used as a small and light bypass switch in a satellite battery or the like.

It is sectional drawing which shows Embodiment 1 of the bypass switch which concerns on this invention. It is the circuit diagram which connected the bypass switch of this Embodiment 1 in parallel with the cell of a storage battery. It is sectional drawing which shows Embodiment 2 of the bypass switch which concerns on this invention.

Explanation of symbols

1 case, 10 thermal actuator, 11 pressurizer, 21, 22 fixed conductor,
23 Movable conductor, 31, 32 Ribbon conductor, 33 Diode check terminal,
41, 42 Diode, 43, 44 Metal plate, 45 Solder,
46,47 Metal plate, 51 shaft, 100 cells.

Claims (8)

A fixed conductor composed of a pair of fixed conductors, and a pair of fixed conductors arranged between the pair of fixed conductors with a predetermined gap in a direction perpendicular to the pair of fixed conductors, and driven in a direction perpendicular to the pair of fixed conductors. In the bypass switch having a switch portion having a movable conductor made of a conductor connecting the fixed conductors,
A pressurizing device that pressurizes the movable conductor in a direction perpendicular to the pair of fixed conductors;
A semiconductor element that generates heat when energized and receives a pressure applied to the movable conductor, a first metal plate in contact with the semiconductor element, solder in contact with the first metal plate, and a first sandwiching the solder together with the first metal plate A thermal actuator in which two metal plates are stacked in a direction in which the pressure device pressurizes,
A conductor that electrically connects the switch unit and the thermal actuator in parallel to form a parallel circuit;
The parallel circuit is connected in parallel to each of a plurality of cells connected in series with a storage battery, and the cells are connected in parallel so that the semiconductor element is not normally energized but is electrically energized to the semiconductor element in an abnormal state. Then, the solder is melted by the heat generated by the semiconductor element, the thermal actuator is displaced by the pressure applied by the pressurizing device, and the movable conductor is displaced vertically in the direction of the fixed conductor. A bypass switch, wherein the pair of fixed conductors are electrically connected by the movable conductor to form a bypass circuit that short-circuits the abnormal cell. The bypass switch according to claim 1, wherein the conductor is a flexible ribbon conductor. 2. The bypass switch according to claim 1, wherein another semiconductor element is provided so as to sandwich the first metal plate, the solder, and the second metal plate together with the semiconductor element. 2. The bypass switch according to claim 1, wherein a heat capacity of the first metal plate is larger than a heat capacity of the solder. 4. The bypass switch according to claim 3, wherein a total heat capacity of the first metal plate and the second metal plate is larger than a heat capacity of the solder. 2. The bypass switch according to claim 1, wherein a groove is formed on a surface of the first metal plate that contacts the solder. 4. The bypass switch according to claim 3, wherein a groove is formed on a surface of at least one of the first metal plate and the second metal plate in contact with the solder. 2. The bypass switch according to claim 1, wherein a tin-silver based lead-free solder is used as the solder.

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