JP2022108299A - Power module device - Google Patents

Abstract

To suppress increase in size of the whole device.SOLUTION: A power module device comprises a power module with a power element enclosed therein, a coolant case having a passage formed to flow a coolant therein, a lid member that seals the passage in the coolant case, the power module being placed on the opposite side of the coolant case, and a water leakage sensor that is mounted on the lid member and detects water leakage, the lid member having a screw hole formed as a blind hole opening to the opposite side of the coolant case, the water leakage sensor being mounted on the opposite side of the lid member by a screw screwed in the screw hole, at least a part of a partition member that separates the screw hole of the lid member from the passage is formed thinner than a part excluding the partition, of the lid member contacting the passage.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a power module device, and more particularly to a power module device that includes a power module, a refrigerant case, a lid member, and a water leakage sensor.

Conventionally, this type of power module device has been proposed to include a power module (component), a coolant case (second structure), and a lid member (base plate) (for example, Patent Document 1 reference). The coolant case forms a channel through which water flows. The lid member seals the passage of the refrigerant case, and the power module is mounted on the opposite side of the refrigerant case. In this device, first and second conductor wires are provided at the junction between the coolant case and the cover member. The second conductor line is in contact with the first conductor line through the insulating layer. A sign of water leakage is detected by detecting continuity between the first and second conductor wires.

JP 2019-179807 A

However, the above-described power module device cannot predict the water leakage occurrence position. Therefore, in order to improve the detection accuracy of signs of water leakage, it is necessary to arrange a configuration for detecting water leakage between the first and second conductor wires and the insulating layer over the entire joint between the refrigerant case and the cover member. , the configuration for detecting water leakage becomes large.

A main object of the power module device of the present invention is to suppress an increase in the size of the entire device.

The power module device of the present invention employs the following means in order to achieve the above main object.

The power module device of the present invention is
a power module containing a power element;
a coolant case in which a flow path for coolant is formed;
a lid member that seals the flow path of the coolant case and mounts the power module on the side opposite to the coolant case;
a water leakage sensor attached to the lid member for detecting water leakage;
A power module device comprising
The lid member is formed with a screw hole as a blind hole that opens on the side opposite to the refrigerant case,
The water leakage sensor is attached to the opposite side of the lid member by a screw that is screwed into the screw hole,
At least a portion of the partition section that partitions the screw hole and the flow path of the lid member is formed thinner than a portion of the lid member contacting the flow path, excluding the partition section. This is the gist of it.

In the power module device of the present invention, the lid member is formed with screw holes as blind holes that open on the side opposite to the refrigerant case. A water leak sensor is attached to the opposite side of the lid member by a screw that threads into the threaded hole. At least a portion of the partition separating the screw hole of the lid member from the flow path is formed thinner than the portion of the lid member contacting the flow path excluding the partition. Therefore, the partitioning portion is likely to cause water leakage due to corrosion or the like earlier than the portion of the lid member other than the partitioning portion, which is in contact with the flow path. When a water leak occurs in the partition, water enters the screw hole and travels along the screw to reach the water leak sensor, which detects the water leak. As a result, water leakage can be detected with a simpler configuration without arranging a configuration for detecting water leakage over the entire joint portion between the refrigerant case and the lid member. As a result, an increase in size of the entire device can be suppressed.

In such a power module device of the present invention, the coolant case is made of metal, the cover member is made of a different kind of metal from the coolant case, and the lid member is formed in the vicinity of a portion that contacts the coolant case. A threaded hole may be formed. Since the coolant case and the lid member are made of different kinds of metals, that is, metals with different ionization tendencies, if water enters the contact portion between the coolant case and the lid member, it is likely to corrode. By forming a screw hole in the vicinity of the portion of the cover member that contacts the refrigerant case, which is a portion that is likely to corrode, and attaching the water leakage sensor with a screw that is screwed into the screw hole, water leakage can be detected more accurately.

Further, in the power module device of the present invention, the lid member may have a recess formed on the side opposite to the refrigerant case, and the screw hole may be formed at the bottom of the recess. In this way, water that has entered the screw hole due to water leakage accumulates at the bottom of the recess, so that the water leakage sensor can detect water leakage with higher accuracy.

Further, in the power module device of the present invention, the water leakage sensor includes a thermistor resistor attached to the power module side of the lid member with the screw through the mounting terminal, and one end thereof is connected to one end of the thermistor resistor. a second wiring having one end connected to the other end of the thermistor resistor; a third wiring having one end connected to the end of the first wiring on the thermistor resistor side; a fourth wiring connected to the end of the two wirings on the thermistor resistor side and having the other end spaced apart from the other end of the third wiring by a predetermined distance, between the power source and the first wiring; and a detection circuit that detects voltages between the first wiring and the second wiring. By doing so, it is possible to determine whether or not water leakage occurs based on the voltages of the first wiring and the second wiring.

1 is a configuration diagram showing a schematic configuration of a power module device 20 as an embodiment of the present invention; FIG. 2 is an enlarged configuration diagram showing an outline of a main part of the power module device 20; FIG. FIG. 3 is a schematic diagram showing an outline when the water leakage sensor 28 is viewed from above in FIG. 2; 4 is a graph showing an example of the relationship between the temperature and resistance value of a thermistor resistor 280; 3 is an explanatory diagram showing an example of an equivalent circuit of a water leakage detection system including a water leakage sensor 28, a resistor R, and a detection circuit 310; FIG. FIG. 4 is an explanatory diagram showing an example of a change over time of a voltage V12 between a line L1 and a line L2; It is a block diagram which shows an example of the power module apparatus 120 of a modification.

Next, a mode for carrying out the present invention will be described using examples.

FIG. 1 is a configuration diagram showing an outline of the configuration of a power module device 20 as one embodiment of the present invention. FIG. 2 is an enlarged configuration diagram showing an outline of a main part of the power module device 20. As shown in FIG. The power module device 20 of the embodiment is mounted, for example, on an electric vehicle or a hybrid vehicle that can be driven by power from a motor. (hereinafter referred to as “ECU”) 30 .

The power module 22 has a power element enclosed therein. Examples of power elements include diodes and IGBTs that constitute boost converters, inverters, and the like, which are driven by relatively large currents and generate relatively large amounts of heat.

The coolant case 24 is made of, for example, the ADC 21 with high thermal conductivity. The coolant case 24 is configured as a case that opens upward in FIG. 1 and forms a water channel 240 (channel) through which coolant (cooling water or the like) flows. Although not shown, the coolant case 24 is formed with an introduction hole for introducing cooling water and a discharge hole for discharging the coolant.

The lid member 26 is made of A1100 having high thermal conductivity, for example, and seals the opening of the coolant case 24 to seal the water channel 240 of the coolant case 24 . The power module 22 is mounted on the opposite side of the cover member 26 from the refrigerant case 24 via an insulating substrate 23 with high thermal conductivity. A plurality of fins are formed on the refrigerant case 24 side of the lid member 26 to promote heat exchange between the refrigerant and the power module 22 via the lid member 26 and the insulating substrate 23 having relatively high thermal conductivity. there is A screw hole 260 is formed as a blind hole opening on the side opposite to the refrigerant case 24 near the portion of the cover member 26 that contacts the refrigerant case 24 . In the screw hole 260, the thickness Th1 of the partition portion 262 between the screw hole 260 of the lid member 26 and the water channel 240 is thinner than the portion 264 of the portion of the lid member 26 in contact with the water channel 240 excluding the partition portion 262. (For example, the thickness Th1 of the partition portion 262 is 1 mm, 2 mm, 3 mm, etc., and the thickness of the portion 264 is 4 mm, 5 mm, 6 mm, etc.).

FIG. 3 is a schematic diagram showing the outline when the water leakage sensor 28 is viewed from above in FIG. FIG. 4 is a graph showing an example of the relationship between the temperature of the thermistor resistor 280 and the resistance value. The water leakage sensor 28 includes a thermistor resistor 280 and wires L1 to L4.

The thermistor resistor 280 is attached to one surface of the lid member 26 on the power module 22 side with a screw 40 that is screwed into the screw hole 260 via the attachment terminal T. As shown in FIG. As shown in FIG. 4, the resistance value of the thermistor resistor 280 is lower when the temperature is high than when the temperature is low. The thermistor resistor 280 is adjusted so that the resistance value is sufficiently high within the temperature range in which the power module device 20 normally operates.

The wires L1 and L2 are made of a conductor having good electrical conductivity (for example, aluminum), and are arranged above the lid member 26 so as to be substantially parallel to each other. One end of the wiring L1 is connected to one end of the thermistor resistor 280, and the other end is connected to a power supply (power supply voltage Vh. For example, 3.5V, 5V, etc.) via a resistor R, which will be described later. The wiring L2 has one end connected to the other end of the thermistor resistor 280 and the other end connected to the ground (reference potential, for example, 0 V). The wirings L3 and L4 are made of a conductor having good electrical conductivity (for example, aluminum), and one ends thereof are connected to the ends of the wirings L1 and L2 on the thermistor resistor 280 side. The lengths of the other ends of the wirings L3 and L4 are adjusted so as to maintain a sufficient distance L (for example, 4 mm, 5 mm, 6 mm, etc.) that they are not in contact with each other while facing each other. One ends of the wirings L3 and L4 are connected to the ends of the wirings L1 and L2 on the thermistor resistance 280 side at positions sufficiently close to the thermistor resistance 280 and the screw hole 260 so that water entering the screw hole 260 is splashed. there is

FIG. 5 is an explanatory diagram showing an example of an equivalent circuit of a water leakage detection system including the water leakage sensor 28, the resistor R, and the detection circuit 310. As shown in FIG. FIG. 6 is an explanatory diagram showing an example of temporal change of the voltage V12 between the wiring L1 and the wiring L2. The ECU 30 is configured as a microprocessor centered on a CPU 300. In addition to the CPU 300, the ECU 30 includes a ROM that stores processing programs, a RAM that temporarily stores data, an input/output port, a communication port, a resistor R, and a detection circuit. 310.

Detection circuit 310 outputs voltage V12 between line L1 and line L2 to CPU 300 . When there is no water adhering across the thermistor resistor 280, the resistance value of the thermistor resistor 280 is sufficiently high within the temperature range in which the power module device 20 normally operates. becomes. When water adheres so as to short-circuit both ends of the thermistor resistor 280, the water short-circuits the wiring L3 and the wiring L4, and the voltage V12 becomes zero. Further, when there is no adhesion of water to the space S between the wiring L3 and the wiring L4 to short-circuit the wiring L3 and the wiring L4, the voltage V12 is pulled up by the resistor R to the power supply voltage Vh. The voltage V12 becomes zero when water adheres to the space S between the wiring L3 and the wiring L4 so as to short-circuit the wiring L3 and the wiring L4. Therefore, when the voltage V12 from the detection circuit 310 is in the vicinity of the power supply voltage Vh, the CPU 300 detects that the thermistor resistor 280 and the gap S between the wiring L3 and the wiring L4 is free of water. When the voltage V12 from the power supply voltage Vh is 0, it can be detected that water is attached to at least one of the thermistor resistor 280 and the space S between the wiring L3 and the wiring L4.

In the power module device 20 of the embodiment configured in this manner, the partition portion 262 is thinner than the other portion 264, so cracks due to corrosion or the like are likely to occur early. In addition, since the refrigerant case 24 and the cover member 26 are made of different metals and have different ionization tendencies, if water enters the contact area between the refrigerant case 24 and the cover member 26, cracks due to corrosion will occur. Likely to happen. As described above, the partition portion 262 is more susceptible to cracking due to corrosion than the other portion 264 , and the coolant flowing through the water passage 240 is more likely to leak.

When water leakage occurs in the partition portion 262 , water enters the screw hole 260 and travels along the screw 40 to reach the water leakage sensor 28 . When the water reaching the water leakage sensor 28 is applied to the thermistor resistor 280 and short-circuits both ends of the thermistor resistor 280, the resistance value of the thermistor resistor 280 decreases. Become. Further, when the water reaching the water leakage sensor 28 is caught between the ends of the wiring L3 and the wiring L4 of the water leakage sensor 28 so as to fill the space between the wiring L3 and the wiring L4, the wiring L3 and the wiring L4 are short-circuited, and the wiring L1 and the wiring L2 are connected. The voltage V12 between them has a value of 0. Therefore, when the voltage V12 detected by the detection circuit 310 is 0, the CPU 300 of the ECU 30 determines that there is water that short-circuits the wiring L3 and the wiring L4, that is, water leakage occurs in the partition portion 262. can be detected. As a result, water leakage can be detected with a simpler configuration without arranging a configuration for detecting water leakage over the entire joint portion between the refrigerant case 24 and the lid member 26 . Therefore, it is possible to suppress an increase in the size of the entire device.

According to the power module device 20 of the embodiment described above, the lid member 26 is formed with the screw hole 260 as a blind hole that opens on the side opposite to the refrigerant case 24, and the water leakage sensor 28 is screwed into the screw hole 260. A partition portion 262 that separates a screw hole 260 of the lid member 26 and a water channel 240 (channel) is attached to the opposite side of the lid member 26 by a screw 40 that contacts the water channel 240 (channel). By forming the portion thinner than the portion 264 excluding the partition portion 262, water leakage can be detected with a simpler configuration.

In the power module device 20 of the embodiment, the thermistor resistor 280 is attached to one surface of the lid member 26 on the power module 22 side with the screw 40 screwed into the screw hole 260 via the attachment terminal T. As shown in FIG. However, as illustrated in the power module device 120 of the modified example of FIG. In 266 , screws 40 may be attached over cover member 26 . In this way, water that has entered the screw hole 260 accumulates in the concave portion 266, so that water leakage can be detected more accurately.

In the power module device 20 of the embodiment, the partition portion 262 is formed thinner than the portion 264 of the portion of the cover member 26 that contacts the water channel 240 (channel), excluding the partition portion 262 . However, a portion of the partition portion 262 may be formed thinner than a portion 264 of the portion of the cover member 26 in contact with the water channel 240 (flow path) excluding the partition portion 262 .

In the power module device 20 of the embodiment, the refrigerant case 24 and the lid member 26 are made of dissimilar metals. However, the refrigerant case 24 and the lid member 26 may be made of the same kind of metal.

In the power module device 20 of the embodiment, the refrigerant case 24 is made of, for example, the ADC 21 with high thermal conductivity. However, since the coolant case 24 may be made of a metal with high thermoelectricity, it may be made of a metal such as aluminum that is different from the ADC 21 .

In the power module device 20 of the embodiment, the lid member 26 is made of A1100, which has high thermal conductivity, for example. However, since the cover member 26 may be made of a metal with high thermoelectricity, it may be made of a metal different from A1100, such as aluminum.

In the power module device 20 of the embodiment, the water leakage sensor 28 includes a thermistor resistor 280 and wires L3 and L4. However, the water leakage sensor 28 may include the thermistor resistor 280 without the wirings L3 and L4, or may include the wirings L3 and L4 without the thermistor resistor 280. FIG.

The correspondence relationship between the main elements of the embodiments and the main elements of the invention described in the column of Means for Solving the Problems will be described. In the embodiment, the power module 22 corresponds to the "power module", the refrigerant case 24 corresponds to the "refrigerant case", the cover member 26 corresponds to the "cover member", and the water leakage sensor 28 corresponds to the "water leakage sensor". do.

Note that the correspondence relationship between the main elements of the examples and the main elements of the invention described in the column of Means for Solving the Problems is the Since it is an example for specifically explaining the mode for solving the problem, it does not limit the elements of the invention described in the column of the means for solving the problem. In other words, the interpretation of the invention described in the column of Means to Solve the Problem should be made based on the description in that column, and the Examples should be based on the description of the invention described in the column of Means to Solve the Problem. This is only a specific example.

Although the embodiments for carrying out the present invention have been described above, the present invention is not limited to such embodiments at all, and can be modified in various forms without departing from the scope of the present invention. Of course, it can be implemented.

INDUSTRIAL APPLICABILITY The present invention is applicable to the manufacturing industry of power module devices.

20 power module device, 22 power module, 24 refrigerant case, 26 lid member, 28 water leakage sensor, 30 electronic control unit (ECU), 40 screw, 240 water channel, 260 screw hole, 262 partition, 264 portion, 280 thermistor resistance, 300 CPU, 310 detection circuit, L1 to L4 wiring, R resistor, S air gap, T mounting terminal.

Claims (1)

a power module containing a power element;
a coolant case in which a flow path for coolant is formed;
a lid member that seals the flow path of the coolant case and mounts the power module on the side opposite to the coolant case;
a water leakage sensor attached to the lid member for detecting water leakage;
A power module device comprising
The lid member is formed with a screw hole as a blind hole that opens on the side opposite to the refrigerant case,
The water leakage sensor is attached to the opposite side of the lid member by a screw that is screwed into the screw hole,
At least a portion of a partition section that partitions the screw hole of the lid member from the flow path is formed thinner than a portion of the lid member that is in contact with the flow path, excluding the partition section. .

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