JP6957413B2 - EV relay container - Google Patents

Description

The present disclosure relates to a container for an EV relay.

Demand for environmentally friendly vehicles such as EVs (Electric Vehicles) is increasing against the backdrop of growing awareness of environmental issues such as global warming. And, such an environment-friendly vehicle is equipped with an EV relay so that the secondary battery and the motor / inverter can be safely turned on and off.

Here, the EV relay has an upper wall that is rectangular in front view, and a side wall having four corners following the upper wall, and the portion surrounded by the edge of the side wall is open. It is equipped with a relay container. Further, there is a through hole in the upper wall of the EV relay container, and the EV relay has a fixed terminal located in the through hole and a movable terminal located in the EV relay container facing the fixed terminal. , A metal member located on the edge side of the side wall of the EV relay container, and an elastic body such as a spring connecting the movable terminal and the metal member. When the EV relay is on, the movable terminal is in contact with the fixed terminal, and when the EV relay changes from on to off, the movable terminal is separated from the fixed terminal.

Further, ceramics are widely used for EV relay containers from the viewpoint of insulation and heat resistance (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2012-89489

When the EV relay changes from on to off, when the movable terminal separates from the fixed terminal, an arc (arc-shaped discharge spark) is generated between the fixed terminal and the movable terminal. This arc is extinguished by extending the arc with a magnetic field.

In recent years, secondary batteries used in environmentally friendly vehicles have been replaced by nickel-metal hydride batteries and lithium-ion batteries. Here, when a lithium ion battery is used, the current flowing when the EV relay is on becomes a high voltage and a large current, so that the discharge voltage of the arc generated when the EV relay changes from on to off becomes large.

As described above, when the discharge voltage of the arc becomes large, when the arc is stretched by the magnetic field, the reason is not clear, but the portion of the EV relay container near the edge of the corner is liable to be damaged.

The present disclosure has been devised in view of such circumstances, and an object of the present disclosure is to provide a container for an EV relay in which a portion near the edge of a corner portion is not easily damaged.

The EV relay container of the present disclosure includes an upper wall that is rectangular in front view, and a side wall having four corners following the upper wall. Further, the upper wall and the side wall are made of ceramics. In addition, the portion surrounded by the edge of the side wall is open. The average value of the distance between the centers of gravity of the pores in the first portion of the corner portion near the edge is larger than the average value of the distance between the centers of gravity of the pores in the other portions of the side wall other than the first portion.

In the EV relay container of the present disclosure, the portion near the edge of the corner is not easily damaged.

It is a perspective view which shows an example of the container for EV relay of this disclosure. It is sectional drawing in the ii-ii line of FIG. It is a vertical cross-sectional view which shows an example of the EV relay provided with the container for EV relay of this disclosure.

The EV relay container of the present disclosure will be described in detail below with reference to the drawings.

As shown in FIGS. 1 and 2, the EV relay container 10 of the present disclosure includes an upper wall 1 which is rectangular in front view, and a side wall 2 having four corners 2a following the upper wall 1. Be prepared.

Here, the square shape is not limited to the rectangle as shown in FIG. 1, and may be a square shape. Further, the four corner portions 2a are specifically portions on the side wall 2 that satisfy the following definitions. First, the side wall 2 has four outer surfaces and four inner surfaces corresponding to the outer surfaces. Then, on the side wall 2, the boundary between adjacent outer surfaces is set as the outer ridge line. Specifically, in FIG. 1, when the outer surface of the side wall 2 on the front side shown in the drawing is A and the outer surface of the side wall 2 on the right side shown in the drawing is B, the boundary between the outer surface A and the outer surface B is the outer ridge line, and in FIG. It is the part C shown by the thick line. Similarly, the boundary between adjacent inner surfaces is set as the inner ridge line.

Then, when the surface connecting the outer ridge line and the inner ridge line is regarded as a virtual surface, each corner portion 2a is defined as a portion of the side wall 2 within a range of up to twice the average thickness of the side wall 2 from the virtual surface. .. Here, the average thickness of the side wall 2 is obtained after cutting the EV relay container 10 in the thickness direction of the side wall 2 so as to divide the EV relay container 10 into three equal parts and measuring the thickness of at least three or more side walls 2 on each cut surface. , It may be obtained by calculating the average value of this. If there is a local protrusion on the outer or inner surface of the side wall 2, this protrusion is not measured when calculating the average thickness of the side wall 2 described above.

If the outer ridgeline is not clearly defined because the boundary between adjacent outer surfaces is a curved surface, the virtual plane passing through the plane portion on one outer surface and the plane on the other outer surface on the adjacent outer surfaces. The line that intersects the virtual plane that passes through the location may be regarded as the outer ridgeline. On the other hand, when the inner ridge line is not clearly defined because the boundary between adjacent inner surfaces is a curved surface, the virtual plane passing through the plane portion on one inner surface and the plane on the other inner surface on the adjacent inner surfaces. The line that intersects the virtual plane that passes through the location may be regarded as the inner ridgeline.

Further, the upper wall 1 and the side wall 2 of the EV relay container 10 of the present disclosure are made of ceramics. Here, as the ceramics constituting the upper wall 1 and the side wall 2, aluminum oxide ceramics, silicon nitride ceramics, aluminum nitride ceramics, silicon carbide ceramics and the like can be used. If the upper wall 1 and the side wall 2 are made of aluminum oxide ceramics among the ceramics, there is a low possibility of contaminating the natural environment when the EV relay container 10 is discarded.

Here, the aluminum oxide ceramics contain 70% by mass or more of aluminum oxide in 100% by mass of all the components constituting the ceramics. The same applies to other ceramics.

The materials of the upper wall 1 and the side wall 2 can be confirmed by the following method. First, the upper wall 1 and the side wall 2 are measured using an X-ray diffractometer (XRD), and the obtained values of 2θ (2θ is a diffraction angle) are collated with the JCPDS card. Here, a case where the presence of aluminum oxide is confirmed on the upper wall 1 and the side wall 2 by XRD will be described as an example. Next, quantitative analysis of aluminum (Al) is performed using an ICP emission spectroscopic analyzer (ICP) or a fluorescent X-ray analyzer (XRF). If the content converted from the Al content measured by ICP or XRF into aluminum oxide (Al ₂ O ₃ ) is 70% by mass or more, the upper wall 1 and the side wall 2 are made of aluminum oxide ceramics. There is.

In the EV relay container 10 of the present disclosure, the portion surrounded by the edge of the side wall 2 is open, and the average value of the distance between the centers of gravity of the pores in the first portion 2c near the edge of the corner portion 2 is the side wall. It is larger than the average value of the distance between the centers of gravity of the pores in other parts (hereinafter, may be simply referred to as other parts) other than the first part 2c of 2.

Here, the first portion 2c near the edge of the corner portion 2a is a quarter portion of the edge side of the corner portion 2a when the corner portion 2a is divided into four equal parts in the height direction. That is.

By satisfying such a configuration, even if a crack is generated from the pores by the arc in the first portion 2c, the crack does not easily propagate from the cracked pore to another pore. Therefore, in the EV relay container 10 of the present disclosure, the first portion 2c is not easily damaged.

The average value of the distance between the centers of gravity of the pores in the first site 2c may be 3 μm or more larger than the average value of the distance between the centers of gravity of the pores in the other sites.

Further, in the EV relay container 10 of the present disclosure, the average value of the distance between the centers of gravity of the pores in the first portion 2c may be 20 μm or more and 34 μm or less. If such a configuration is satisfied, the first portion 2c in the EV relay container 10 of the present disclosure is less likely to be damaged.

The average value of the distance between the centers of gravity of the pores in other parts may be, for example, 16 μm or more and 26 μm or less.

Here, the average value of the distance between the centers of gravity of the pores in the first portion 2c may be calculated by the following method. First, as shown in FIG. 2, the EV relay container 10 is cut in the thickness direction of the upper wall 1 so as to pass through the first portion 2c, and the cross section obtained by polishing this cut surface with a cross section polisher (CP) is observed. Make it a face. Next, the first portion 2c on this observation surface is photographed with a metallurgical microscope at a magnification of 300 times or more and 600 times or less. Then, for the range of the photographed photograph, for example, the area is 200,000 μm ² or more and 800,000 μm ² or less, the image analysis software “A image-kun” (registered trademark, manufactured by Asahi Kasei Engineering Co., Ltd., and later image analysis software). When "A image-kun" is written, it means image analysis software manufactured by Asahi Kasei Engineering Co., Ltd.) By applying the method of dispersion measurement to perform image analysis, the pores in the first part 2c The average value of the distance between the centers of gravity can be calculated. Here, as the analysis conditions of the image analysis software "A image-kun", for example, the brightness of the particles is "dark", the binarization method is "automatic", the small figure removal area is 0.1 μm, and the noise removal filter is used. “Yes”, the binarized image correction may be “straight line separation”, and the display method may be “superimposition”.

On the other hand, the average value of the distance between the centers of gravity of the pores in other parts may be calculated by the following method. First, the EV relay container 10 is cut in the thickness direction of the upper wall 1, and the cross section obtained by polishing the cut surface with CP is referred to as an observation surface A. Further, the EV relay container 10 is cut in a direction orthogonal to the thickness direction of the upper wall 1, and the cross section obtained by polishing the cut surface with CP is referred to as an observation surface B. Next, on the observation surfaces A and B, five or more parts other than the first part 2c of the side wall 2 are arbitrarily selected, and images are taken with a metallurgical microscope at a magnification of 300 times or more and 600 times or less. Next, in each photograph taken, for example, an image analysis is performed by applying a technique called dispersion measurement of the image analysis software "A image-kun" to a range in which ^{the area is 200,000 μm 2} or more and 800,000 μm ^{2 or less.} Then, by averaging the distances between the centers of gravity of the pores calculated from a total of five or more points on the observation surfaces A and B, the average value of the distances between the centers of gravity of the pores at other parts can be calculated.

Further, in the EV relay container 10 of the present disclosure, the porosity at the first portion 2c may be smaller than the porosity at the other portions other than the first portion 2c of the side wall 2. If such a configuration is satisfied, cracks originating from pores are less likely to occur in the first portion 2c due to the arc, so that the first portion 2c in the EV relay container 10 of the present disclosure is more damaged. It becomes difficult.

The porosity at the first site 2c may be 2% or more smaller than the porosity at the other sites.

Further, in the EV relay container 10 of the present disclosure, the porosity at the first portion 2c may be 2% or more and 6% or less. If such a configuration is satisfied, the first portion 2c in the EV relay container 10 of the present disclosure is less likely to be damaged.

The porosity at other sites may be, for example, 4% or more and 8% or less.

Here, the porosity at the first site 2c is not the dispersion measurement of "A image-kun" but the dispersion degree measurement of "A image-kun" in the method for measuring the average value of the distance between the centers of gravity of the pores at the first site 2c described above. It can be calculated by analyzing with a technique called particle analysis. On the other hand, the porosity in other parts is referred to as particle analysis of "A image-kun" instead of measuring the dispersion degree of "A image-kun" in the above-mentioned method for measuring the average value of the distance between the centers of gravity of pores in other parts. It can be calculated by analyzing with the method.

Further, in the EV relay container 10 of the present disclosure, the average value of the equivalent circle diameters of the pores in the first portion 2c may be 3 μm or more and 7 μm or less. If such a configuration is satisfied, the first portion 2c in the EV relay container 10 of the present disclosure is less likely to be damaged.

Here, the average value of the equivalent circle diameters of the pores in the first site 2c can be calculated by the same measuring method as the method for measuring the porosity of the pores in the first site 2c described above.

Next, the EV relay 20 including the EV relay container 10 of the present disclosure will be described. First, in the EV relay 20 shown in FIG. 3, two through holes 3 are formed in the upper wall 1 of the EV relay container 10, and the fixed terminal 4 is located in the through holes 3. Specifically, the fixed terminal 4a is located in the through hole 3a, and the fixed terminal 4b is located in the through hole 3b. Although FIG. 3 shows an example in which there is a gap between the fixed terminal 4 and the through hole 3, the fixed terminal 4 and the through hole 3 may be sealed by brazing or the like.

Further, in the EV relay 20, a metal member 7 is attached to the edge of the side wall 2 of the EV relay container 10 so as to close the opening formed by the end of the side wall 2. Further, there is a movable terminal 5 at a position facing the fixed terminal 4 in the EV relay container 10, and the movable terminal 5 and the metal member 7 are joined by an elastic body 6 such as a spring.

Here, the movable terminal 5 has a structure that moves up and down due to a magnetic action by a magnetic material (not shown) or the like. Then, when the movable terminal 5 rises and the movable terminal 5 and the fixed terminal 4 come into contact with each other, a current supplied by a power source (not shown) flows from one of the fixed terminal 4a and the solid terminal 4b to the other via the movable terminal 5. .. On the other hand, when the movable terminal 5 is lowered and the movable terminal 5 is separated from the fixed terminal 4, the current is cut off. At this time, an arc is generated between the fixed terminal 4 and the movable terminal 5. Then, the generated arc is stretched and extinguished by the magnetic action of a magnet or the like (not shown). Here, in the case of the EV relay container 10 of the present disclosure, as described above, the first portion 2c is less likely to be damaged.

Next, a method for manufacturing the EV relay container 10 of the present disclosure will be described below. Here, a case where the upper wall 1 and the side wall 2 of the EV relay container 10 are made of aluminum oxide ceramics will be described as an example.

First, aluminum oxide (Al ₂ O ₃ ) powder is prepared as a main raw material. Further, as a sintering aid, silicon oxide (SiO ₂ ) powder, calcium carbonate (CaCO ₃ ) powder and magnesium carbonate (MgCO ₃ ) powder are prepared.

Next, each powder (main raw material and firing aid) is weighed and mixed so that the content of aluminum oxide becomes 70% by mass or more after firing, and a ball mill using a known method, for example, ion-exchanged water is used. A primary slurry is prepared by performing wet pulverization with. Next, an organic binder, a dispersant and a mold release agent are added to the primary slurry and further mixed to prepare a secondary slurry. Next, the secondary slurry is spray-dried by a known method to prepare granules.

Here, two types of granules having different average particle sizes are prepared. Hereinafter, granules having a large average particle size will be referred to as first granules, and granules having a small average particle size will be referred to as second granules.

Next, a mold in the shape of the EV relay container 10 is prepared. Then, the first granules are filled in the portion of the EV relay container 10 that becomes the first portion 1c in the mold. Next, the rest of the mold is filled with the second granules. Then, by performing press molding, a molded body in the shape of the EV relay container 10 is produced. By producing the molded body in this way, after firing by a known firing method, the average value of the distance between the centers of gravity of the pores in the first portion 2c is larger than the average value of the distance between the centers of gravity of the pores in the other portions. Obtain a large EV relay container 10 of the present disclosure.

Further, in order to make the average value of the distance between the centers of gravity of the pores in the first site 2c 20 μm or more and 34 μm or less, the first granules having an average particle size of 120 μm or more and 180 μm or less may be used. In order to make the average value of the distance between the centers of gravity of the pores at other sites 16 μm or more and 26 μm or less, the second granule having an average particle size of 40 μm or more and 90 μm or less may be used.

Further, in order to make the porosity at the first site 2c smaller than the porosity at the other sites, prepressurization may be performed after the mold is filled with the first granules and before the second granules are filled. ..

Further, in order to make the porosity in the first portion 1c 2% or more and 6% or less, the pressure of the above-mentioned preliminary pressurization may be 10 MPa or more and 30 MPa or less.

Further, in order to make the average value of the equivalent circle diameters of the pores in the first portion 1c 3 μm or more and 7 μm or less, in the wet pulverization when producing the first granules, ion-exchanged water is added to each powder (main raw material and firing aid). The agent) may be added so as to be 80 parts by mass or more and 120 parts by mass or less with respect to 100 parts by mass in total.

1: Upper wall 2: Side wall 3, 3a, 3b: Through hole 4, 4a, 4b: Fixed terminal 5: Movable terminal 6: Elastic body 7: Metal member 10: EV relay container 20: EV relay

Claims (6)

The upper wall, which is square in front view,
Following the upper wall, a side wall having four corners is provided.
The upper wall and the side wall are made of ceramics.
The portion surrounded by the edge of the side wall is open.
The average value of the distance between center of gravity of the pores in the first region of the cross section closer to the edge of the corner is greater than the average value of the distance between center of gravity of the pores in other areas of the cross-section except for the first portion of the side wall EV relay container. The EV relay container according to claim 1, wherein the average value of the distance between the centers of gravity of the pores in the first portion is 20 μm or more and 34 μm or less. The EV relay container according to claim 1 or 2, wherein the porosity at the first portion is smaller than the porosity at other portions of the side wall other than the first portion. The EV relay container according to any one of claims 1 to 3, wherein the porosity at the first portion is 2% or more and 6% or less. The EV relay container according to any one of claims 1 to 4, wherein the average value of the equivalent circle diameters of the pores in the cross section of the first portion is 3 μm or more and 7 μm or less. The EV relay container according to any one of claims 1 to 5, wherein the ceramic is an aluminum oxide ceramic.

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