JP7411150B2 - power supply connector - Google Patents

Description

The present invention relates to a power supply connector.

Typical conventional power transmission connectors include household plugs and power supply plugs for electric vehicles (Chademo, etc.). These plugs have an inherent contact resistance (R).
Therefore, when the amount of current (I) to flow increases, a loss of RI2 occurs. Since heat generation occurs as the square of the current flowing through it, low contact resistance is extremely important in high current applications.
From this point of view, conventional contacts have a large resistance and generate heat when used in large current applications.
If a large current is applied in such a state, the contact portion will generate heat, which will melt the electrodes and cause them to become stuck together, and oxidation will be promoted.

On the other hand, in order to improve the troublesomeness of using contacts, magnetic field coupling non-contact power supply technology and electric field coupling non-contact power supply technology have been studied (for example, see Patent Document 1).
These methods increase the scale of equipment, do not improve power transmission efficiency, increase power transmission costs, and have limits on the amount of power that can be transmitted. Furthermore, electromagnetic waves are emitted to the outside, which may determine the limits of transmitted power.

Unexamined Japanese Patent Publication No. 2021-16206

However, the conventional technology including the invention of Patent Document 1 requires increasing the equipment scale, resulting in high costs. There is also a limit to the amount of power that can be transmitted. Furthermore, although there are some differences depending on the power supply technology, electromagnetic waves may be radiated to the outside, which may affect the limit of the power that can be transmitted. In addition, magnetic field coupling contactless power supply technology uses copper coils and ferrite magnetic materials, which increases the weight and generates heat. Furthermore, with the advent of all-solid-state batteries in recent years, there is a need to establish power supply technology that allows rapid charging.

The present invention was made in view of this situation, and aims to review the conventional contact-type power supply technology and provide a technology that allows rapid charging by flowing a large current using the contact method. do.

In order to achieve the above object, the power supply connector according to the present invention includes:
a first metal electrode;
a conductive layer having viscoelasticity and having conductivity disposed on the surface of the first metal;
a second metal electrode that is brought into contact across the conductive layer by being moved when power is being supplied, and is separated by being moved when not being supplied with power;
Equipped with
Furthermore, a low melting point metal is provided on opposing surfaces of the conductive layer and the second metal electrode, each with conductivity and fixing means.

According to the present invention, it is possible to review the conventional contact type power supply technology and provide a technology that allows rapid charging by flowing a large current using the contact type.

FIG. 3 is a diagram showing a contact interface between general rigid electrodes. FIG. 3 is a diagram showing a state in which a rubber-lined thin plate electrode placed on a rigid electrode on a power transmission side is brought into contact with a rigid electrode on a power reception side. It is a figure which shows the pressing state when pressing force is applied in the arrow direction from the state of FIG. 2A. FIG. 3 is a diagram showing a state in which a large current BI is passed from the rigid electrode on the power transmission side to the rigid electrode on the power reception side in the pressed state of FIG. 2B. FIG. 3 is a diagram (graph) showing changes in contact resistance due to pressure and current application. It is a cross section showing a contact type power supply connector (an example of a split type electrode structure) of a second embodiment. FIG. 4A is a perspective view of FIG. 4A viewed from the bottom side. 4A is a diagram showing a state in which the rigid electrode on the power transmission side is pressed in the direction of the arrow to sandwich the conductive layer from the state in FIG. 4A. FIG. FIG. 2 is a cross-sectional view showing an example in which a thin plate electrode and a rigid electrode on the power receiving side are each coated with a low melting point metal. 6A is a sectional view showing a pressed state when a pressing force is applied in the direction of the arrow from the state shown in FIG. 6A. FIG. 6B is a cross-sectional view showing a state in which a large current is passed from the rigid electrode on the power transmission side to the rigid electrode on the power reception side in the pressed state of FIG. 6B. FIG. FIG. 3 is a diagram showing a state in which metal fibers are impregnated with a low melting point metal and attached to the surface of an electrode. FIG. 7A is a cross-sectional view of FIG. 7A; FIG. 3 is a diagram showing how a rigid electrode and a metal fiber are made of the same material and fixed by resistance welding. FIG. 3 is a diagram showing a state in which the sintered metal fibers impregnated with a low melting point metal are separated from each other in an electrode structure in which sintered metal fibers impregnated with a low melting point metal are arranged in rigid electrodes for power transmission and power reception. 8A is a diagram showing a state in which melting point metal-impregnated sintered metal fibers are brought into contact with each other from the separated state in FIG. 8A. FIG. It is a diagram showing a structure in which a rubber-impregnated sintered metal fiber and a low-melting point metal-impregnated sintered metal are laminated on one electrode, and a low-melting-point metal-impregnated sintered metal fiber is laminated on the other electrode. FIG. 4 is a diagram showing an example in which a rubber-impregnated sintered metal fiber 51 and a low-melting point metal layer 62 are arranged on one electrode 31, and a low-melting point metal-impregnated sintered metal fiber 52 is arranged on the other electrode 32. FIG. 3 is a diagram showing a state in which rubber-impregnated sintered metal fibers are separated from one rigid electrode in an electrode structure for floor power transmission. FIG. 3 is a diagram showing a state in which rubber-impregnated sintered metal fibers are pressed by upper and lower rigid electrodes.

Embodiments of the present invention will be described below with reference to the drawings.
First, a general contact interface between rigid electrodes will be explained with reference to FIG. FIG. 1 is a diagram showing a contact interface between general rigid electrodes.

As shown in FIG. 1, a general contact type power supply connector has a rigid electrode 1 on the power transmitting side and a rigid electrode 2 on the power receiving side facing each other, and applies a pressing force in the direction of arrow BF to the rigid electrode 1. This is a general electrode structure in which the electrode 1 and the rigid electrode 2 are brought into contact with each other. The rigid electrode 1 and the rigid electrode 2 are each made of metal as a main material.

In a contact type power supply connector having such a configuration, when the rigid electrode 1 and the power receiving side rigid electrode 2 are brought into contact by applying a pressing force to the rigid electrode 1 as shown by the arrow BF, the contact surfaces of each other are metal surfaces. Although they appear flat, when you zoom in on them, there are many unevenness on each surface.
Since the electrodes having such irregularities are rigid bodies, they come into partial contact at the irregularities, and generate heat when a large current is passed between the electrodes.

The cause of the heat generation is the contact point where the rigid electrodes 1 and 2 are brought into contact, and although it appears to have a large contact area (although the apparent contact area is large), when you zoom in on the contact area, it turns out that there are multiple contact areas. This is due to the fact that the true contact area is small because it is made up of contact points.
Further, since the electrodes are used in air, an oxide film SM is naturally formed on the contact interface SK between the electrodes. Furthermore, the more the current is continued, the more the oxide film SM increases due to heating, increasing the resistance. Furthermore, dirt such as dust may get into the gaps between the uneven surfaces.
In addition, in the case of such an electrode structure, even if a pressing force is further applied in the direction of arrow BF and the electrode is pushed in, the area of the contact point PS only increases slightly because the electrode itself is a rigid body.

Hereinafter, with reference to FIG. 2, a contact type power supply connector according to a first embodiment that solves the above-mentioned problem of high contact resistance due to heat generation will be described.
FIG. 2A is a diagram showing a state in which a rubber-backed thin plate electrode placed on a rigid electrode on the power transmission side is brought into contact with a rigid electrode on the power reception side. FIG. 2B is a diagram showing a pressing state when a pressing force is applied in the direction of arrow BF from the state of FIG. 2A. FIG. 2C is a diagram showing a state in which a large current BI is passed from the rigid electrode on the power transmission side to the rigid electrode on the power reception side in the pressed state of FIG. 2B.
2A to 2C are enlarged views of the surface of the rigid electrode 2 and the uneven portion of the thin plate electrode 5 on the power receiving side. Note that although the rigid electrode 1 on the power transmission side also has unevenness, it is shown as a plane in FIGS. 2A to 2C to make the explanation easier to understand.

As shown in FIG. 2A, the contact type power supply connector of the first embodiment includes a rigid electrode 1 on the power transmission side, a rigid electrode 2 on the power reception side, and a conductive layer 6 including a thin plate electrode 5 lined with rubber 4. Be prepared.
The rigid electrode 2 on the power receiving side is fixed.
The rigid electrode 1 on the power transmission side is moved so as to be pressed against the rigid electrode 2 by a pressing force applied in the direction of the arrow BF shown in FIG. 2B.
The rigid electrode 1 on the power transmission side is disposed to face the rigid electrode 2 on the power reception side with a predetermined interval in the non-power feeding state.

As shown in FIG. 2A, when the rigid electrode 1 on the transmitting side and the rigid electrode 2 on the receiving side are in contact with each other, since both the rigid electrode 2 on the receiving side and the thin plate electrode 5 have unevenness, there are multiple dot-like contact points. I am in contact with.

When the thin plate electrode 5 provided on the rigid electrode 1 on the power transmitting side is pressed against the rigid electrode 2 on the power receiving side as shown in FIG. 2B, it deforms according to the unevenness of the surface of the rigid electrode 2, and the contact point The area increases.
At this time, since the low melting point metal 6a is also soft, it adapts to the irregularities of the rigid electrode 2 on the power receiving side. As the pressing force in the direction of arrow BF is increased, the conductive layer 6 including the thin plate electrode 5 is crushed, the contact area of the contact point increases, and the contact resistance decreases.

By applying the above-mentioned pressing force during power supply, the distance between the rigid electrode 1 on the power transmission side and the rigid electrode 2 on the power reception side is narrowed. Furthermore, when power is not being supplied, the rigid electrode 1 on the power transmitting side is moved in the opposite direction to the direction of the arrow BF, thereby increasing the distance from the rigid electrode 2 on the power receiving side.

The conductive layer 6 consists of an elastic member such as rubber or rubber, and a thin plate electrode (thin plate electrode 5 bent in a U-shaped cross section in FIG. 4A) made of a thin flexible metal material so as to surround the elastic body. have
The conductive layer 6 is disposed between the rigid electrodes 1 and 2, is sandwiched between the rigid electrodes 1 and 2 by movement during power supply, and is sandwiched between the rigid electrodes 1 and 2 by movement during non-power supply. separated.

In the example of FIG. 2A, the conductive layer 6 is a thin plate electrode 5 lined with rubber 4. Therefore, as shown in FIG. 2B, it has elasticity (collapses and returns to its original state) in the direction of arrow BF to which pressing force is applied and in the opposite direction. That is, the conductive layer 6 has viscoelasticity. Viscoelasticity includes at least one of elasticity and viscosity.

The conductive layer 6 is sandwiched between the rigid electrodes 1 and 2 due to the movement of the rigid electrode 1 on the power transmission side during power supply. When power is not being supplied, the rigid electrode 1 on the power transmission side is moved in the opposite direction to the direction of the arrow BF, thereby separating it from either one of the rigid electrodes 1 and 2.

In this example, since the conductive layer 6 is fixed to the rigid electrode 1 side, the conductive layer 6 is separated from the rigid electrode 2.
Specifically, the conductive layer 6 includes a rubber 4 fixed to the bottom surface of the rigid electrode 1 on the power transmission side with an elastic adhesive layer 3, a thin plate electrode 5 fixed to the bottom surface of the rubber 4 with an elastic adhesive layer 3, and a thin plate electrode 5 and a low melting point metal 6a coated on the surface thereof. Note that a liquid metal may be applied instead of the low melting point metal 6a.

Here, the low melting point metal 6a and the liquid metal will be explained.
The low melting point metal 6a is solid at room temperature, but begins to melt at a temperature slightly higher than room temperature (for example). There are many types of low melting point metals with different melting points, such as wood metals. Since many of the low melting point metals 6a are soft metals, it is expected that the contact area will increase somewhat due to the pressure between the electrodes. In this case, when a large current is applied, the current flows through the contacts and melts them, increasing the contact area. As a result, resistance can be reduced. In addition, in the case of the low melting point metal 6a, it may contain harmful substances such as cadmium, so it is necessary to use it in a place where humans cannot come into contact with it.

As the liquid metal, a eutectic alloy of GaInSn (Galinstan) or the like is used. The melting point of the eutectic alloy of GaInSn (Galinstan) is -19°C, and it liquefies at higher temperatures, such as room temperature. The liquid metal in the liquefied state is rubbed against the thin plate electrode 5 until it becomes wettable, so it is not peeled off.
Further, since the thin plate electrode 5 coated with liquid metal is usually covered with an oxide film, it does not oxidize. When the rigid electrode 1 on the power transmitting side is pressed, a portion of the liquid metal is also transferred to the opposing rigid electrode 2 on the power receiving side, but no problem occurs even if the contacting electrodes are inserted incorrectly. Therefore, when the rigid electrode 1 is pressed, the liquid metal enters the gap between the electrodes, thereby achieving low contact resistance.

In the contact type power supply connector having the electrode structure shown in FIG. 2A, when power is supplied from the rigid electrode 1 on the power transmission side to the rigid electrode 2 on the power reception side, as shown in FIG. When a pressing force is applied in the direction of BF, the conductive layer 6 consisting of the rubber 4, the elastic adhesive layer 3, the thin plate electrode 5, etc. changes its shape to match the uneven shape of the rigid electrode 2 on the power receiving side and comes into contact with the rigid electrode 2. Therefore, the gap 7 formed between the rigid electrode 2 and the rigid electrode 2 is narrowed, and the contact resistance is reduced.
The thin plate electrode 5 included in the conductive layer 6 is thin, for example, 50 μm or more and 150 μm or less, so it can be connected to the lower rigid electrode 2 on the power receiving side as a small intermediary electrode interposed between the rigid electrodes 1 and 2 with low resistance. be done.

When a large current BI is passed from the rigid electrode 1 on the power transmission side to the rigid electrode 2 on the power reception side in the pressed state of FIG. 2B as shown in FIG. 2C, the contact point is heated and the melting point (melting point) of the low melting point metal 6a is temperature), the low melting point metal 6a melts and becomes a liquid metal, which flows into the gap 7 as shown in the area 9 in FIG. Therefore, contact can be made with a wider contact area.

Such a low melting point metal 6a is solid at normal temperatures, but becomes a liquid metal 6b as the temperature increases. In either state, the oxide film SM prevents the low melting point metal or liquid metal itself from being oxidized.

If the conductive layer 6 and the rigid electrode 2 on the power receiving side are brought into contact and separated many times, the oxide film SM will be diffused into the low melting point metal 6a or the liquid metal, and the conductive performance will deteriorate. For this reason, it is desirable to replace the low melting point metal 6a on the surface of the rigid electrode 1 at regular intervals.
When separated, the low melting point metal 6a may remain on the surface of the rigid electrode 2 on the power receiving side, but this can be considered as unevenness on the surface of the rigid electrode 2 on the power receiving side. Alternatively, the surface of the rigid electrode 2 may be removed by polishing.

Here, with reference to FIG. 3, the results of an experiment using the rubber-lined thin plate electrode 5 and the low melting point metal 6b will be explained.
FIG. 3 is a diagram (graph) showing changes in contact resistance due to pressure and current application.
First, as an initial condition, seven samples of 1 square centimeter copper plates (thin plate electrodes 5) whose surfaces were coated with liquid metal 6b or low melting point metal 6a were prepared and left for about two weeks.

In the graph of FIG. 3, as the pressing force is increased to 1.1 kg, 3.0 kg, 4.9 kg, and 6.8 kg for these seven samples, the contact resistance decreases in accordance with the pressing force. It can be seen that the resistance value decreases significantly when a current of 10 A is applied.
From the above experimental results, it can be said that the hypothesis that contact resistance can be reduced with the electrode structure shown in FIG. 2 is correct.

According to the contact type power supply connector of the first embodiment, the rigid electrode 1 on the power transmission side and the conductive layer 6 including the thin plate electrode 5 lined with rubber 4 are disposed on the rigid electrode 1, and the power supply At this time, by pressing the rigid electrode 1 on the power transmission side and pressing the rigid electrode 1, the conductive layer 6, and the rigid electrode 2, the conductive layer 6 comes into close contact with the rigid electrode 2 due to the elasticity of the conductive layer 6. Electrical resistance decreases, allowing large currents to flow. By passing a large current, the contact area is heated and the low melting point metal is liquefied and blended in, making it possible to further lower the resistance. As a result, it is possible to provide an electrode structure that can support rapid charging.

Next, a contact type power supply connector according to a second embodiment will be described with reference to FIGS. 4A, 4B, and 5.
FIG. 4A is a cross section showing a contact type power supply connector (an example of a split electrode structure) according to the second embodiment. FIG. 4B is a perspective view of FIG. 4A viewed from the bottom side. FIG. 5 is a diagram showing a state in which the rigid electrode on the power transmission side is pressed in the direction of arrow BF from the state shown in FIG. 4A to sandwich the conductive layer 6.
As shown in FIGS. 4A and 4B, the contact type power supply connector of the second embodiment has an electrode structure including the rigid electrode 1 shown in FIG. 2A and a conductive layer 6 having a thin plate electrode 5 lined with rubber 4. The groups are arranged in an array.

The thin plate electrode 5 itself is thin and has high resistance in the planar direction. For this reason, a plurality of conductive layers 6 are arranged for one rigid electrode 1, and the width of each conductive layer 6 is about 10 mm. Further, in order to reduce the resistance, the thin plate electrode 5 of each conductive layer 6 is bent upward at both ends and connected to the side surface of the rigid electrode 1, thereby reducing the resistance of the electrode as a whole. As an example, as shown in FIG. 11, it is fixed by soldering.

An elastic insulating material 12 is arranged between each conductive layer 6 . The elastic insulating material 12 allows each conductive layer 6 to twist or shift in the lateral direction when a pressing force is applied, and prevents dust from remaining.
The rubber 4 is, for example, a plate-shaped rubber having a thickness of 0.5 mm or more and 2 mm or less and a side length of 5 mm or more and 20 mm or less. Rubber 4 is sandwiched between rigid electrode 1 and thin plate electrode 5.

Reference numeral 5 included in the conductive layer 6 is an electrode having a thickness of, for example, 50 μm or more and 150 μm or less. The thin plate electrode 5 is fixed to the rigid electrode 1 on the power transmitting side with an elastic adhesive layer 3 and a plate-shaped rubber 4, and the pressing force in the direction of arrow BF is transmitted to the rigid electrode 2 on the power receiving side via these.

Specifically, the thin plate electrode 5 includes the rubber 4 using the elastic adhesive layer 3 so as to obtain conductivity with the rigid body electrode 1 and not to prevent elastic deformation of the rubber 4 in the thickness direction. The required number of electrodes are arranged in units that include the rubber 4 so that the necessary contact area with the electrode 2 can be obtained, and when the rigid electrode 1 is pressed against the rigid electrode 2, the rubber 4 and the thin plate electrode Reference numeral 5 denotes an electrode having elasticity that deforms together to improve adhesion to the rigid electrode 2.

If heat is dissipated properly even at contacts with such an electrode structure, if silicone rubber or the like is used as the rubber 4, a large current of about 50 A per square centimeter can be generated within the practical temperature range (e.g. 200°C). BI power transmission is possible.
Furthermore, the thickness of the thin plate electrode 5 is suitably, for example, 50 μm or more and 150 μm or less.
As described above, if the area is increased, even larger current BI power transmission is possible. However, the pressing force in the direction of arrow BF must be increased according to the area.

The electrode structure shown in FIG. 4A can cope with minute irregularities on the surface of the counter electrode, but as shown in FIG. , the conductive layer 6 deforms to correspond to the shape of the undulations.
Even larger undulations can be dealt with by providing spring properties to the bases of the rigid electrode 1 on the power transmitting side and the rigid electrode 2 on the power receiving side.

Here, improvement of the electrode structure will be explained.
In the electrode structures of FIGS. 2, 4, and 5 described above, only one of the rigid electrodes 1 of the rigid electrode 1 on the power transmission side and the rigid electrode 2 on the power reception side is provided with a low melting point metal 6a (depending on the temperature, it becomes a liquid metal). , a contact interface SK exists on the surface of the other rigid electrode 2. For this reason, a sufficiently low contact resistance cannot be obtained on the power receiving side, and at the same time, high contact pressure and a combination of the thin plate electrode 5 and the rubber 4 are required to compensate for this.

Therefore, by disposing a low melting point metal 6a on the rigid electrode 2 on the power receiving side that faces the rigid electrode 1, the point contact part is melted by flowing a large current BI after contact, and the low melting point metal 6a is liquefied and mixed. Therefore, the contact resistance can be further reduced, and the pressing force BF can also be reduced.

The contact type power supply connector of the third embodiment will be described below with reference to FIGS. 6A, 6B, and 6C. FIG. 6A is a cross-sectional view showing an example in which a thin plate electrode and a rigid electrode on the power receiving side are each coated with a low melting point metal. FIG. 6B is a cross-sectional view showing a pressed state when a pressing force is applied in the direction of arrow BF from the state shown in FIG. 6A. FIG. 6C is a cross-sectional view showing a state in which a large current BI is passed from the rigid electrode on the power transmission side to the rigid electrode on the power reception side in the pressed state of FIG. 6B.
6A to 6C show an enlarged view of the surface of the rigid electrode 2 and the uneven portion of the thin plate electrode 5 on the power receiving side. Although the rigid electrode 1 on the power transmission side also has irregularities, in order to make the explanation easier to understand, the surface of the rigid electrode 1 on the power transmission side is shown as a plane in FIGS. 6A to 6C.

In this third embodiment, as shown in FIGS. 6A to 6C, not only the low melting point metal 6a of the rigid electrode 1 on the power transmission side but also the low melting point metal 6b is arranged on the rigid electrode 2 on the power receiving side.
The manufacturing process up to FIGS. 6A and 6B is the same as that shown in FIGS. 2A and 2B, but in the region 10 of FIG. 6C, the low melting point metals 6a and 6b melt and fuse together, forming the contact interface SK (see FIG. 1). We have been able to achieve contact without any problems.

Initially, an oxide film SM is formed on the low melting point metal 6a to prevent further oxidation. After melting, the oxide film SM is mixed with the fused low melting point metals 6a and 6b, resulting in a bond without a contact interface SK. This makes it possible to achieve low contact resistance without increasing contact pressure too much.

According to the third embodiment, contact resistance can be further reduced compared to the example of FIG. 2 by applying a low melting point metal to each of the thin plate electrode and the rigid electrode on the power receiving side.

Here, the contact type power supply connector of the fourth embodiment will be described with reference to FIGS. 7A, 7B, and 7C.
FIG. 7A is a diagram showing a metal fiber impregnated with a low melting point metal and attached to the electrode surface. FIG. 7A is a plan view showing a plain weave metal fiber formed by weaving metal wires in the vertical and horizontal directions (the weaving method is not limited to plain weave). FIG. 7B is a cross-sectional view of FIG. 7A (with two fibrous layers, but is not limited thereto). FIG. 7C is a diagram showing how the rigid electrode and the metal fiber are made of the same material and melted and fixed by resistance welding or laser welding, but brazing, soldering, etc. may also be used.

In this fourth embodiment, a description will be given of how the low melting point metal 6a can be localized on the surface of the thin plate electrode 5 or the surface of the rigid electrode 1 on the power transmission side.
A simple method for fixing the low melting point metal 6a to the rigid electrode 31 is to melt the low melting point metal into liquid metal and impregnate it into the metal fibers 21.

Another possible method is to pre-deposit a highly adhesive metal (for example, gold) (interface metal layer 61). When copper is used for the thin plate electrode 5 or the rigid electrode 31 on the power transmission side, the adhesion between copper and gold is high, and the wettability (affinity) between gold and low melting point metal is also high, so the interface metal layer 61 is interposed. This makes it difficult for the low melting point metal 6a and the copper electrode to separate, and the conductivity is also improved.

In a contact type power supply connector, when the electrode is repeatedly connected and separated, it is conceivable that a specific portion (convex portion) of the same electrode may be hit many times. As a result, it is possible that the low melting point metal in the specific region is transferred to the other electrode. Considering that the power transmitting side and the power receiving side are switched and different electrodes are always brought into contact with and separated from each other, the probability that the convex part will hit is high, although this point will change.

It is necessary to increase the amount of the low melting point metal 6a on the assumption that the low melting point metal 6a is transferred to other parts. For this purpose, the following first method and second method can be considered.
The first method is to provide an interface metal layer 61 on the electrode surface and provide a low melting point metal thereon.
The second method is to attach a metal fabric to the electrode surface and impregnate the low melting point metal 6a therein.

Here, the second method will be explained.
In this case, by weaving the metal wires in the vertical and horizontal directions, a plain weave metal fiber 21 is formed as shown in FIG. 7A. Then, the plain weave metal fiber 21 is impregnated with the low melting point metal 6a to form a low melting point metal impregnated metal fiber.
Finally, as shown in FIG. 7B, the formed metal fiber impregnated with a low melting point metal is fixed to the surface of the electrode 31.

A method of fixing the low melting point metal 6a to the surface of the electrode 31 is, for example, as shown in FIG. The impregnated metal fibers 21 are fixed by spot welding. Spot welding is one type of resistance welding.
In this example, resistance welding was used, but other welding methods may be used, such as soldering, brazing, arc discharge welding, laser welding, or even a method in which metal fibers are sandwiched between metal plates and fixed with screws. good. However, when fixing with screws, make sure that the screw heads do not protrude from the contact surface.

Next, a contact type power supply connector according to a fifth embodiment will be described with reference to FIGS. 8A and 8B.
FIG. 8A is a diagram showing a state in which the sintered metal fibers impregnated with a low melting point metal are separated from each other in an electrode structure in which sintered metal fibers impregnated with a low melting point metal are arranged in rigid electrodes for power transmission and power reception.
FIG. 8B is a diagram showing a state in which the melting point metal-impregnated sintered metal fibers are brought into contact with each other from the separated state in FIG. 8A.

As shown in FIG. 8A, sintered metal fibers 41 impregnated with a low melting point metal are arranged on the rigid electrode 31 on the power transmission side and the rigid electrode 32 on the power reception side without using rubber 4 or the like.
The low melting point metal impregnated sintered metal fiber 41 is a sintered metal fiber impregnated with a low melting point metal 6a. As the metal fiber, either woven fabric or non-woven fabric is selected and used. The metal fibers are fused and fixed to the rigid electrodes 31 and 32.

When impregnating the metal fiber with the low melting point metal 6a, since the low melting point metal 6a is solid below the melting point, it is liquefied at a temperature above the melting point and then impregnated into the metal fiber, and then cooled to below the melting point. solidify and integrate.
When using copper, for example, as the metal fiber, the resistance between the thread and the low melting point metal 6a can be reduced by plating the metal wire (thread) from which the fiber is woven with a metal such as gold. can be done. A method of plating the surfaces of the rigid electrodes 31 and 32 with metal such as gold may also be adopted.

Since the low melting point metal 6a is solid at a temperature below its melting point, it has no fluidity within the solid and the surface oxide film SM prevents internal oxidation. Therefore, it can be left unused for a long period of time. If the maximum temperature of the environment in which the low melting point metal 6a is used is set below the melting point of the low melting point metal 6a, it will not become liquid before use.

When the low melting point metal impregnated sintered metal fibers 41 of the respective rigid electrodes 1 and 2 come into contact with and separate from each other many times and the oxide film SM on the surface of the low melting point metal 6a is taken into the inside, the melted low melting point metal 6b Metals can be replaced and regenerated by soaking them in water.

When a metal such as gallium (hereinafter referred to as "Ga") is used as the low melting point metal 6a, its melting point is about 30.degree. C. and becomes a liquid metal in summer.
Even if the low-melting point metal 6a becomes a liquid metal, the low-melting point metal-impregnated sintered metal fiber 41 has a holding power against the liquid metal, and the surface oxide film SM prevents further oxidation, so that it does not turn into a liquid metal. Even if it does, problems such as deterioration and leakage will not occur.

As shown in FIG. 8B, when a pressing force in the direction of arrow BF is applied to the rigid electrode 1, the rigid electrode 1 approaches the rigid electrode 2, and the low melting point metal impregnated sintered metal fibers 41 come into close contact with each other. In addition, since the low melting point metal 6a contained in the low melting point metal impregnated sintered metal fiber 41 is a soft solid, the low melting point metal impregnated sintered metal fiber 41 is not crushed.
However, in the region 42 where the low melting point metal-impregnated sintered metal fibers 41 are in contact with each other through the rigid electrodes 1 and 2, the low melting point metals 6a are in contact with each other. In such a situation, if a large current is applied and the temperature rises, the Ga will liquefy and there will be no contact interface, creating a good contact.

Even in the state where the low melting point metal 6a is liquefied, the threads constituting the low melting point metal impregnated sintered metal fibers 41 are subjected to pressure in the sandwiched state shown in FIG. 8B, but a gap corresponding to the thickness of the threads is maintained.
When the gap is reduced due to pressure, the liquefied low melting point metal 6a (liquid metal) contained in the low melting point metal impregnated sintered metal fibers 41 seeps out, and the low melting point metal impregnated sintered metal fibers 41 of each other ooze out. The metal fibers are in even better contact with each other so that there are no boundaries between the metal fibers.

Here, a case will be considered in which the respective low melting point metal impregnated sintered metal fibers 41 are separated from each other as shown in FIG. 8A from a state in which they are in contact as shown in FIG. 8B.
When Ga is a liquid, when the respective low melting point metal impregnated sintered metal fibers 41 are separated, they are easily separated.

On the other hand, when Ga is solidified as a low-melting point metal 6a, its Young's modulus is 9.8 GPa and its Mohs hardness is 1.5, which means that its mechanical strength is extremely weak. It can be divided into
At this time, since the low melting point metal impregnated sintered metal fibers 41 are fixed on the power transmission side and the power receiving side, the low melting point metal impregnated sintered metal fibers 41 do not peel off from the rigid electrodes 31 and 32 when they are separated. Instead, stress concentrates only on the part where the two Ga parts are in contact with each other, and the two parts are separated at this part.
Ga has the advantage of being relatively inexpensive as a resource and being harmless.

Next, a contact type power supply connector according to a sixth embodiment will be described with reference to FIG.
FIG. 9 is a diagram showing a structure in which a rubber-impregnated sintered metal fiber 51 and a low-melting point metal-impregnated sintered metal fiber 52 are laminated on one electrode, and a low-melting point metal-impregnated sintered metal fiber 52 is laminated on the other electrode. It is.
Although the electrode structures in FIGS. 8A and 8B are simple, there is no correspondence between the concavities and convexities of opposing rigid electrodes.
Therefore, in the sixth embodiment, the low melting point metal-impregnated sintered metal fiber 52 is still used, but the electrode structure is made to have flexibility as illustrated in FIGS. 4A to 4C.

In the case of this sixth embodiment, as shown in FIG. 9, sintered metal fibers are welded to electrodes 31 in advance, immersed in liquid rubber 4 (silicon rubber, etc.), and the air inside the sintered metal fibers is heated in a vacuum. By drawing out the liquid rubber 4, the sintered metal fiber is impregnated with the liquid rubber 4, thereby forming a rubber-impregnated sintered metal fiber 51. The liquid rubber 4 contains a curing agent that hardens after a certain period of time, and is cured after sufficient air has been removed.

After the rubber 4 is cured, excess rubber is removed from the rubber-impregnated sintered metal fiber 51, and the metal surface of the sintered metal fiber is exposed. Then, metal is deposited on the exposed portion to form an interface metal layer 61. This interface metal layer 61 is a layer that is wetted after the low melting point metal impregnated sintered metal fiber 52, which is a sintered metal fiber impregnated with a low melting point metal, is attached.

Thereafter, the sintered metal fibers 52 impregnated with a low melting point metal are arranged and fixed on the bottom surface of the interface metal layer 61. At that time, the low melting point metal is once liquefied to wet the interface metal layer.
Note that on the side of the electrode 32, an interface metal layer 62 is formed in the same manner as the electrode 31, and a low melting point metal impregnated sintered metal fiber 52 is arranged and fixed on the upper surface of the interface metal layer 62.
As a method for fixing the low melting point metal impregnated sintered metal fiber 52, welding is performed by providing a welding point 34 as shown in FIG. 7C at a position that does not inhibit the elastic behavior of the respective surfaces of the electrodes 31 and 32. .

Sintered metal fibers alone will dent (plastic deformation) when a pressing force is applied from the outside in the direction of arrow BF, but by using rubber-impregnated sintered metal fibers 51 impregnated with liquid rubber, elasticity is ensured. It adapts to the unevenness of the facing surface and can be used many times.
Furthermore, compared to the electrode structures shown in FIGS. 4A, 4B, and 4C, this structure has the advantage of being easier to manufacture because only sintered metal fibers are interposed between the electrodes 31 and 32.

Next, a contact type power supply connector according to a seventh embodiment will be described with reference to FIG.
In FIG. 10, a rubber-impregnated sintered metal fiber 51 and an interface metal layer 62 are arranged on one electrode 31, and a low melting point metal is wetted. FIG. 3 is a diagram showing an example in which a low melting point metal impregnated sintered metal fiber 52 is arranged on the other electrode 32.
That is, the example shown in FIG. 10 is an application example in which the electrode structure shown in FIG. 9 is further simplified, and the same components as those in FIG. 9 are given the same reference numerals, and the explanation thereof will be omitted.

In the manufacturing method of the seventh embodiment, as in the example of FIG. expose. Then, a metal different from that in the example of FIG. 9 is deposited on the exposed portion to form an interface metal layer 61. As this metal, a metal material that is compatible with the sintered metal fiber and has good wettability with a low melting point metal is used.
After forming the interface metal layer 61, a low melting point metal is liquefied and applied to the surface of the interface metal layer 61 to form a low melting point metal layer 63.

As an example of a combination of a sintered metal fiber, a low melting point metal, and a metal to be vapor-deposited, if copper wire is used as the sintered metal fiber, and Ga or the like is used as the low melting point metal, the adhesion and conductivity to copper will be high. For example, gold is used as a metal that can be obtained. Gold also has good wettability with liquid Ga. By forming the interface metal layer 61 using such a metal, it becomes possible to form an intermediary layer (conductive layer 6) between electrodes that has both adhesion and conductivity.

Next, a contact type power supply connector according to the eighth embodiment will be described with reference to FIGS. 11A and 11B. FIG. 11A is a diagram showing a state in which rubber-impregnated sintered metal fibers are separated from one rigid electrode in an electrode structure for floor power transmission. FIG. 11B is a diagram showing the rubber-impregnated sintered metal fiber in contact with the upper and lower rigid electrodes.

The examples shown in FIGS. 11A and 11B are examples in which the rubber-impregnated sintered metal fiber 81 itself becomes the electrode, and specifically, the electrode 72 (SUS or nickel-plated electrode, etc.) placed on the floor on the power supply equipment side A case is assumed in which an electrode 71 disposed on a moving object such as a robot or an AGV (Automated Guided Vehicle) receives power transmitted from a robot.

As shown in FIGS. 11A and 11B, the contact type power supply connector of the eighth embodiment is constructed by disposing rubber-impregnated sintered metal fibers 81 between electrodes 71 and 72.
Specifically, a rubber-impregnated sintered metal fiber 81 is fixed to the bottom surface of the electrode 71, and when the electrode 71 is moved downward during power supply, the rubber-impregnated metal fiber 81 is formed between the electrode 71 and the electrode 72. The eroded sintered metal fiber 81 is sandwiched and pressed by the electrode 71 and comes into contact with the electrode 72 .
As a result, the electrodes 71 and 72 are electrically connected through the rubber-impregnated sintered metal fiber 81 in a low-resistance state, making it possible to supply power with little heat generation when a large current is passed between the electrodes 71 and 72. Become.

The electrode 71 is a power receiving side electrode placed on the moving object. The electrode 72 is a power transmission side electrode provided integrally with the floor. A protruding stud 82 is provided on the surface of the electrode 72. The electrode 72 has strength, abrasion resistance, acid resistance, alkali resistance, and design properties as a floor material, and can also be used as an anti-slip stud or Braille block.

An electrode 71 placed on a moving body such as a robot or an AGV that has moved for power supply is placed above the electrode 72 and facing the electrode 72 . That is, when the moving body stops, the electrode 71 is pressed from above and moves downward, becomes electrically conductive with the electrode 72 through the rubber-impregnated sintered metal fiber 81, and becomes capable of receiving electricity. The protruding studs 82 prevent it from slipping sideways.

A rubber-impregnated sintered metal fiber 81 is fixed to the bottom surface of the electrode 71.
The rubber-impregnated sintered metal fiber 81 functions as a conductive layer. The rubber-impregnated sintered metal fiber 81 is an electrode in which rubber 4 is impregnated into a sintered metal of a woven or nonwoven fabric to expose the metal fibers on the front and back sides of the sintered metal, and is fixed to the rigid electrode 1. ing.

The rubber-impregnated sintered metal fiber 81 is an electrode having viscoelasticity so that when the electrode 71 is pressed against the electrode 72, it is elastically deformed and improves adhesion to the electrode 72.
The rubber-impregnated sintered metal fiber 81 is made of, for example, a metal fiber woven with SUS, chrome-plated copper wire, nickel-plated copper wire, or the like.

In a contact type power supply connector with such an electrode structure, after lowering the electrode 71 and bringing the electrodes 71 and 72 into contact with each other so as to press the electrode 72 with the rubber-impregnated sintered metal fiber 81, the electrode 72 is connected from the floor side electrode 72. By supplying power to the electrode 71, the robot or AGV receives power through the electrode 71.

In this eighth embodiment, when the protruding rivet 82 sticks into the rubber-impregnated sintered metal fiber 81, the metal wire constituting the rubber-impregnated sintered metal fiber 81 is pushed away, and the pushed away metal wire becomes the protruding rivet. Good contact is obtained by licking the surface of 82.

In this example, the rubber-impregnated sintered metal fiber 81 is used, and the aforementioned low-melting point metal 6a (see FIGS. 2 and 7A) is not used, so that the floor surface is not contaminated.

Furthermore, when the rubber-impregnated sintered metal fibers 81 are placed on the soles of the robot's feet, the rubber comes into contact with the floor surface when pressed, so that it can also serve as an anti-slip function. The metal fibers 21 made of sintered metal also bite into the floor etc. and function as a slip prevention means. This electrode is not used for rapid charging, but for sequential power supply.

As described above, according to the eighth embodiment described above, an all-solid-state battery is introduced, and rapid charging can be performed safely and routinely. If this happens, power can be supplied extremely quickly not only to robots and AGVs, but also to electric devices such as EV cars, drones, electric agricultural machinery, and power tools, thereby improving the usability of the devices.

If the charging speed is faster, the amount of activity of the mobile object will also increase. For this purpose, contact electrodes that do not generate heat during large current transmission are required.
Furthermore, it is also necessary to consider a method of sequentially supplying power to the mobile body. Rubber-impregnated sintered metal fiber 81 is effective for such uses. It is assumed that the social need for such electrodes is extremely large.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within the range that can achieve the purpose of the present invention are included in the present invention. It is.

For example, in the first embodiment described above, the rigid electrode 2 on the power receiving side is set at a fixed position and the rigid electrode 1 on the power transmitting side is moved. However, these relationships may be reversed, and the rigid electrode 1, 2 can both be on the power transmitting side or the power receiving side.

Furthermore, the change between low melting point metal and liquid metal is determined by the environmental temperature, but by providing a heater, heat exchanger, and Peltier element in the electrode part, it is possible to intentionally change the state into a liquid phase or a solid phase. is also possible. Particularly in extremely cold regions, it is difficult to achieve contact between liquid metals, but using a heater can easily bring the metals into a liquid phase or near-liquid phase state. Although not shown in each figure, such a function is assumed to be provided.

In other words, the power supply connector to which the present invention is applied only needs to have the following configuration, and can take various embodiments.

That is, the power supply connector to which the present invention is applied (for example, the contact type power supply connector shown in FIG. 2),
A first metal electrode that can be on the power transmission side or the power reception side (for example, the rigid electrode 2 on the power reception side in FIG. 2),
The first metal electrode (e.g., rigid electrode 2 in FIG. 2) is arranged opposite to the first metal electrode (e.g., rigid electrode 2 in FIG. 2) with a predetermined distance therebetween, and the distance between the first metal electrode (e.g., rigid electrode 2 in FIG. 2) narrows during power supply. a second metal electrode (for example, the rigid electrode 1 on the power transmission side in FIG. 2), which is moved in the direction in which the distance is increased when the power is not supplied;
disposed between the first metal electrode and the second metal electrode, sandwiched between the first metal electrode and the second metal electrode by the movement during the power supply, and the movement during the non-power supply; a conductive layer having viscoelasticity (for example, the conductive layer 6 in FIG. 2) separated from either the first metal electrode or the second metal electrode by;
Equipped with
The advent of all-solid-state batteries has the potential to significantly change the world, but for this to happen, it is necessary to develop a power supply connector that can rapidly charge all-solid-state batteries.
In this way, by providing a contact structure that allows a large current to flow for rapid charging, rapid charging can be made possible.

The power supply connector to which the present invention is applied (for example, the contact type power supply connectors shown in FIGS. 4A, 4B, and 5) is as follows:
In a contact type power supply connector that supplies power between a power transmission electrode made of a rigid electrode (for example, rigid electrode 1 on the power transmission side in FIG. 5) and a power receiving electrode (for example, rigid electrode 2 on the power reception side in FIG. 5). ,
The power transmission electrode is
A first layer made of a rigid electrode (for example, the rigid electrode 1 on the power transmission side in FIG. 5, etc.), a second layer made of an elastic member (for example, the rubber 4 in FIG. 5, etc.), and a thin plate electrode having flexibility (for example, A third layer (such as the thin plate electrode 5 in FIG. 5) is laminated in that order, and a flexible adhesive layer (such as the elastic adhesive layer 3 in FIG. ) are glued together by
The third layer (for example, the thin plate electrode 5 in FIG. 5) is
It is formed by arranging the thin plate electrodes 5 divided into predetermined sizes in an array,
Each end of the thin plate electrode 5 divided into the predetermined sizes and the first layer are connected by a conductor (thin metal plate) that can be deformed by pressing,
By contacting the power receiving electrode (for example, the rigid electrode 2 on the power receiving side in FIG. 5) by pressing, the power from the power transmitting electrode (for example, the rigid electrode 1 in FIG. 5) is transferred to the conductor (thin metal plate). Power is transmitted to the power receiving electrode (for example, the rigid electrode 2 on the power receiving side in FIG. 5) through the power receiving electrode.

In a power transmission connector that quickly charges DC current from a power source,
There is a rigid electrode (for example, rigid electrode 1 in FIG. 5) and a thin plate metal electrode (for example, thin plate electrode 5 in FIG. 5) having a thickness of 50 μm or more and 150 μm or less, which is bonded via flexible rubber and adhesive. A flexible elastic member and a thin metal electrode are divided into rectangles of 5 mm or more and 20 mm or less, and the thin metal electrode stands up at the divided boundary and is connected to a rigid electrode (for example, rigid electrode 1 in FIG. 5). , has a small electrode (for example, a conductive layer, etc.) having a bent part whose rising part is elastically deformed,
A large number of the small electrodes (for example, the conductive layer 6, etc.) are arranged in an array to form a flexible contact electrode (for example, the thin plate electrode 5, etc.),
In the flexible contact electrode (for example, the thin plate electrode 5), the surface of the thin plate electrode 5 is coated with a low melting point metal 6a or a liquid metal.
According to such a configuration, when the flexible contact electrode (for example, the thin plate electrode 5, etc.) is held between the opposing rigid electrodes (for example, the rigid electrode 2 in FIG. 5), the flexible contact electrode (for example, the thin plate electrode 5, etc.) Since it deforms according to the uneven shape of the rigid electrode (for example, rigid electrode 2 in FIG. 5) and makes contact flexibly, the contact area between the flexible contact electrode (for example, thin plate electrode 5, etc.) and the rigid electrode 2 is expanded, resulting in low contact resistance. can be realized.
At this time, the low melting point metal 6a on the surface of the thin plate electrode 5 is also deformed by the pressure, increasing the contact area and lowering the contact resistance, but the point contact state is maintained.
Furthermore, due to the act of transmitting large amounts of power under pressure, the point contact part generates heat, and the low melting point metal changes to liquid metal, which spreads between the thin plate electrode 5 and the rigid electrode 2, expanding the electrical contact area and lowering the contact point. resistance can be achieved.
Originally, when the low melting point metal on the surface of the thin plate electrode 5 is liquefied, when the contact area between the rigid electrode and the flexible contact electrode expands, the liquid metal spreads to fill the gap, resulting in low contact resistance. realizable.

DESCRIPTION OF SYMBOLS 1... Rigid electrode on the power transmission side, 2... Rigid electrode on the power receiving side, 3... Elastic adhesive layer, 4... Rubber, 5, 32... Thin plate electrode, 6a, 6b... Low melting point Metal, 11... Soldering part, 12... Elastic insulator, 31... Rigid electrode, 33... Welding crimp electrode, 41, 51... Low melting point metal impregnated sintered metal fiber, 51 , 81... Rubber impregnated sintered metal fiber, 52... Low melting point metal impregnated sintered metal fiber, 61... Interface metal layer, 62... Low melting point metal coating layer, 71... Moving body side Power receiving electrode, 72...Power transmitting electrode on the floor side, 82...Protruding stud, PS...Contact point, BF...Arrow (direction of pressing force), SK...Contact interface, SM...・Oxide film, BI... large current

Claims (3)

a first metal electrode;
a second metal electrode that is spaced apart from and faces the first metal electrode;
Equipped with
A low melting point metal that can maintain a softened or liquefied state at the operating temperature is fixed to the opposing surface of at least one of the first metal electrode and the second metal electrode,
A pressing force is applied between the first metal electrode and the second metal electrode so that the first metal electrode and the second metal electrode come into contact with each other, thereby enabling electricity to flow;
When the pressure between the first metal electrode and the second metal electrode is released, the first metal electrode and the second metal electrode are separated and become non-conductive.
connector. A woven metal fiber or a sintered metal nonwoven fabric fixed to at least one surface of the first metal electrode and the second metal electrode by welding or soldering;
a layer in which the woven metal fiber or the sintered metal nonwoven fabric is impregnated with the low melting point metal and fixed;
The connector according to claim 1, comprising:. a metal layer fixed to at least one surface of the first metal electrode and the second metal electrode by vapor deposition or plating, and having wettability with respect to the low melting point metal;
a layer in which the metal layer is wetted with a low melting point metal;
The connector according to claim 1, comprising:.

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