JP2008311023A - Bypass switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem, wherein the contact resistance becomes unstable since a movable electrode cannot add sufficient load to one contact face of a fixed electrode, when the center line of the movable electrode is decentered from symmetry due to the manufacturing tolerance, or the like, of the movable electrode and the fixed electrode, in a bypass switch in which a cell put into in a high resistance state or into an opened circuit state is short-circuited, by bringing the movable electrode into contact with the fixed electrode. <P>SOLUTION: In the center part of the movable electrode, a U-shaped groove is formed, and a shaft connected to the U-shaped groove is arranged so that the radius of curvature is smaller than that of the U-shaped groove of the movable electrode, as well as, the width is formed into a small arc shape. According to this, the movable electrode is arranged at the center of one set of the fixed electrodes, and the load is made to be uniformly added to the contact faces of two fixed electrodes. Moreover, by forming the shape of the movable electrode in contact with the fixed electrodes into a curved shape, the contact resistance of the fixed electrode and the movable electrode is further stabilized. <P>COPYRIGHT: (C)2009,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 against a failure in which one cell is in a high resistance state or an open circuit state, a bypass switch that connects a thermal actuator to each cell in parallel and short-circuits the faulty cell triggered by the heat generated by the thermal actuator at the time of failure Is provided. 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, for example, a movable electrode that is displaced in a direction perpendicular to a pair of fixed electrodes by a pressure applied by a pressure device, and a thermal actuator that receives a pressure applied to the movable electrode via a shaft are provided.

  Then, a parallel circuit of a switch unit composed of a pair of fixed electrodes and movable electrodes and a thermal actuator is formed, and when the cell is abnormal, the thermal actuator is displaced by the pressure of the pressurizer, and the fixed electrode is moved by the movable electrode. A bypass switch that is electrically connected to short-circuit an abnormal cell is disclosed (for example, see Patent Document 1).

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

  In the case of such a configuration, normally, the contact shape of the fixed electrode and the movable electrode is designed to be symmetric, but if the center line of the movable electrode is decentered from the symmetric due to manufacturing tolerances of the fixed electrode and the movable electrode, etc. Since the movable electrode is fixed to the pressurizing device and there is no escape of force, a sufficient load is not applied to one contact surface.

  Accordingly, the force applied to the contact point of the fixed electrode becomes non-uniform, and the contact resistance becomes unstable. Therefore, there exists a subject that the electricity supply performance at the time of a cell short circuit cannot fully be satisfied.

  The eccentricity referred to here is a state in which the stress at the contact point between the fixed electrode and the movable electrode is not symmetrical and is biased to either the left or right electrode of the movable electrode.

  The present invention has been made to solve such problems, and an object of the present invention is to stabilize the contact resistance by devising the shape of the movable electrode with respect to the fixed electrode.

The bypass switch according to the present invention is
Bypass switch connected in parallel to each battery cell connected in series,
A fixed electrode comprising a pair of fixed electrodes;
When the cell is in a high resistance state or an open circuit state, a shaft that can be displaced in a vertical direction with respect to the fixed electrode composed of the fixed pair of electrodes;
A predetermined gap in the vertical direction is arranged with respect to the gap between the fixed electrodes composed of the fixed pair of electrodes, and when the shaft is displaced, the pressure is applied in the vertical direction by a pressure device, A movable electrode that is electrically connected to a fixed electrode to short-circuit the cell;
With
A U-shaped groove is formed in the movable electrode,
The shaft in contact with the U-shaped groove has an arc shape smaller than the radius of curvature of the U-shaped groove, and the width of the shaft is smaller than the width of the U-shaped groove.

  According to the present invention, even when there is a manufacturing tolerance or the like in the movable electrode, the movable electrode and the shaft always come into contact with each other, and the movable electrode can be arranged at the center of a set of fixed electrodes. As a result, a load can be applied uniformly to the contact surfaces of the two fixed electrodes and the movable electrode, and non-uniform contact resistance is eliminated, so that contact resistance can be stabilized.

Embodiment 1 FIG.
1 is a cross-sectional view of a bypass switch according to Embodiment 1 of 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, a fixed electrode 2, 3 made of a pair of electrodes fixed to the case 1, and a fixed electrode 2, 3. A switch unit having a movable electrode 4 which is disposed between the fixed electrodes 2 and 3 with a predetermined gap and is connected to the fixed electrodes 2 and 3 by being driven in a direction perpendicular to the fixed electrodes 2 and 3. It has.

  Note that the “predetermined gap” is a gap between the fixed electrodes 2 and 3 and the movable electrode 4 before the thermal actuator 7 described later operates (see FIG. 3).

  The bypass switch includes a pressurizing device 6 composed of a coil spring or the like that pressurizes the movable electrode 4 and the shaft 5 in a direction perpendicular to the fixed electrodes 2 and 3. When the thermal operation device 7 is operated, the shaft 5 is moved downward by the pressurization of the pressurization device 6, and the switch is operated by the movable electrode 4 being in line contact with the fixed electrodes 2 and 3 in conjunction therewith. .

  FIG. 2 is a circuit diagram when the bypass switch according to Embodiment 1 of the present invention is connected in parallel with a battery cell. As shown in FIGS. 1 and 2, for example, a diode 8 is provided inside the thermal actuator 7.

  According to the configuration of the circuit diagram shown in FIG. 2, when the cell 11 is in a normal state, a reverse voltage is applied to the diode 8 so that no current flows and the bypass switch does not operate. However, if the cell 11 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 conducted through the metal plate 9 inside the thermal actuator 7 shown in FIG. 1, and the solder 10 is heated and melted. When the solder 10 is melted, the metal plate 9, the diode 8, the shaft 5, and the movable electrode 4 are pushed by the pressure device 6 and can be moved downward in the stacking direction of the metal plate 9, the diode 8, and the like. 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 11 is formed.

  FIG. 3 is a detailed view of the movable electrode 4 according to Embodiment 1 of the present invention. A U-shaped groove is formed at the center of the movable electrode 4. As shown in FIG. 3, the shaft 5 connected to the U-shaped groove has an arc shape having a smaller radius of curvature and a smaller width than the U-shaped groove of the movable electrode 4.

  By adopting such a shape, even when there is a manufacturing tolerance of the movable electrode 4, the center of the radius of curvature of the movable electrode 4 and the center of the radius of curvature of the shaft 5 are always in contact with each other. It can be arranged in the center of a set of fixed electrodes 2 and 3. As a result, the load is uniformly applied to the contact surfaces of the two fixed electrodes 2 and 3 and the movable electrode 4, so that the contact resistance becomes non-uniform and the contact resistance of the contact surface can be stabilized.

  In order to stabilize the surface state relative to the surrounding environment and reduce the contact resistance, for example, the fixed electrodes 2 and 3 and the movable electrode 4 are subjected to soft gold plating. Furthermore, in order to reduce the contact resistance, for example, the material of the fixed electrodes 2 and 3 and the movable electrode 4 is made of copper or copper alloy having high conductivity and low hardness.

Embodiment 2. FIG.
FIG. 4 is a detailed view of a contact portion between the fixed electrode 2 and the movable electrode 4 according to Embodiment 2 of the present invention. 4A shows a conventional contact portion between the fixed electrode 2 and the movable electrode 4, and FIG. 4B shows a contact portion between the fixed electrode 2 and the movable electrode 4 in the shape of the movable electrode 4 according to the present invention. .

  Since the shape of the contact surface of the conventional movable electrode 4 is a hard edge as shown in FIG. 4A, the contact surface with the fixed electrodes 2 and 3 is a line contact. On the other hand, the shape of the movable electrode 4 according to the present invention increases the contact area between the fixed electrodes 2 and 3 and the movable electrode 4 by making the shape of the contact portion a curved shape. Therefore, the contact resistance can be reduced.

  Accordingly, the contact resistance is further stabilized by making the shape of the movable electrode 4 a curved shape rather than making the movable electrode 4 a hard edge as in the prior art.

  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 of the bypass switch which concerns on Embodiment 1 of this invention. It is a circuit diagram when the bypass switch which concerns on Embodiment 1 of this invention is connected in parallel with the cell 11 of the storage battery. It is detail drawing of the movable electrode 4 which concerns on Embodiment 1 of this invention. It is detail drawing of the contact part of the fixed electrode 2 and the movable electrode 4 which concerns on Embodiment 2 of this invention.

Explanation of symbols

1. Case 2. Fixed electrode 3. Fixed electrode 4. 4. movable electrode Shaft 6. Pressurizing device 7. Thermal actuator 8. Diode 9. Metal plate 10. 10. Solder cell

Claims (2)

In the bypass switch connected in parallel to each of the cells of the battery connected in series,
A fixed electrode comprising a pair of fixed electrodes;
When the cell is in a high resistance state or an open circuit state, a shaft that can be displaced in a vertical direction with respect to the fixed electrode composed of the fixed pair of electrodes;
A predetermined gap in the vertical direction is arranged with respect to the gap between the fixed electrodes composed of the fixed pair of electrodes, and when the shaft is displaced, the pressure is applied in the vertical direction by a pressure device, A movable electrode that is electrically connected to a fixed electrode to short-circuit the cell;
With
A U-shaped groove is formed in the movable electrode,
The bypass shaft, which is in contact with the U-shaped groove, has an arc shape smaller than a radius of curvature of the U-shaped groove, and the width of the shaft is smaller than the width of the U-shaped groove. switch.   The bypass switch according to claim 1, wherein a contact surface of the movable electrode that contacts the fixed electrode has a curved shape.

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