JPH06303704A - Driving device for electric vehicle - Google Patents

Abstract

PURPOSE:To obtain a driving device for an electric vehicle in which the degree of freedoms of designing a collision energy absorption structure is increased by arranging a thickness direction of a cooling board in an attitude of substantially bringing into coincidence with a longitudinal direction of the vehicle in a driver containing chamber. CONSTITUTION:A cooling board 36 has a main section 36a made of a long thick copper plate and a base section 36b for a tube joint. Water supply and drain cooling tubes 40, 41 are passed through a side plate 37a of a case 37, and connected at ends to suction and drain holes provided at the section 36b of the board 36. Output terminals 3U, 3V, 3W protrude from the plate 37a of the case 37 while electrically insulating input terminals 3a, 3, 3c from a side plate 37b. Phase inverters 32-34 are arranged on a main surface of the board 36 at a front side, and a DC/DC converter 35 and a power capacitor 31 are placed in one row longitudinally on a main surface of a rear side. As a result, since a disposition limit of a collision energy absorption structure can be alleviated, the degree of freedoms of designing can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for an electric vehicle.

[0002]

2. Description of the Related Art As a drive system for an electric vehicle, a so-called inverter control system has been adopted in which direct current power from a battery is intermittently controlled by an inverter circuit to supply multi-phase alternating current power to a traveling motor. This inverter circuit has a heat generating electric component such as a semiconductor power switch, and a device for cooling it is required. Then, the actual Kaihei 4-7
As disclosed in Japanese Patent No. 7292, the exothermic electric component is mounted on a cooling board with a cooling fin and made of a block in an electrically insulated manner, and in order to further improve the cooling effect,
An air-cooling system in which forced air is blown to this cooling substrate is applied.

However, the starting current of the running motor of the electric vehicle becomes a large current such as several times or more of the normal running current, and the heat generation of each semiconductor power switch reaches several tens of times (square of current) during normal running. Therefore, in order to prevent the start-up current from temporarily increasing the temperature of the semiconductor power switch and destroying it, the heat capacity of the cooling board as a heat sink is significantly increased as compared with that of a normal power switch cooling board. Therefore, the cooling substrate needs to be large and heavy in order to suppress the temperature rise at the time of startup. However, such a large size and large weight of the cooling substrate has a drawback that it is a very important issue for an electric vehicle, which is contradictory to the improvement of the acceleration by reducing the vehicle weight and the reduction of electric power required for running.

In order to solve this drawback, Japanese Unexamined Patent Publication (Kokai) No. 4-2
As disclosed in Japanese Patent No. 75492, there is proposed a technique of applying a liquid cooling system to improve the cooling performance of a cooling substrate.

[0005]

However, in any of the above-mentioned cooling methods, a large cooling board is required although there is a difference in size between the cooling boards. And, when such a large cooling board is arranged in the drive device storage compartment in the front or rear of the vehicle compartment, the cooling board is less likely to be damaged when a collision occurs depending on the arrangement of the boards,
Since there is a possibility that the collision energy absorbing action due to the breakage of the drive device storage chamber may be obstructed, the layout of other components must be taken into consideration, and the degree of freedom in design is reduced.

Therefore, an object of the present invention is to provide a drive device for an electric vehicle in which the degree of freedom in designing a collision energy absorption structure is expanded.

[0007]

According to a first aspect of the present invention, there is provided a drive device for an electric vehicle, which includes a cooling plate which is made of a thick metal plate and which is disposed in a drive device storage chamber in front of or behind the electric vehicle.
An inverter circuit having a plurality of semiconductor power switches for intermittently controlling a current supplied from a battery to supply power to a traveling motor, and the inverter circuit mounted on the cooling substrate. It is characterized in that it is arranged in the drive device accommodating chamber in a posture that substantially coincides with the direction.

A drive device for an electric vehicle according to a second aspect of the present invention intermittently controls a current supplied from a battery and a cooling substrate which is made of a thick metal plate and is disposed in a drive device storage chamber in the front or rear of the electric vehicle. And a plurality of semiconductor power switches for supplying electric power to the traveling motor, and the inverter circuit mounted on the cooling substrate, wherein the cooling substrate has a hollow structure.

In the first and second inventions, in addition to the inverter circuit, circuit elements such as a power capacitor for smoothing a battery supply current and a DC-DC converter for driving an electric vehicle load are provided on the cooling board. Preferably.

[0010]

According to the first aspect of the present invention, since the cooling substrate is arranged in the drive device accommodating chamber with its plate thickness direction substantially aligned with the vehicle front-rear direction, collision energy is stored in the drive device accommodating space during a collision. When absorbing due to damage in the room,
The cooling board is less of an obstacle. Therefore, it is possible to reduce the restriction on the arrangement of the other components for the collision energy absorption structure due to the arrangement of the cooling substrate in the drive device housing chamber, and it is possible to expand the degree of freedom in design.

According to the second aspect of the invention, since the cooling substrate has a hollow structure, the cooling substrate is likely to be damaged (deformed) along with damage to the drive device housing chamber upon collision. That is, the cooling substrate itself has a collision energy absorbing function. Therefore,
Similar to the first aspect of the invention, it is possible to reduce the arrangement restriction for the collision energy absorbing structure of other components. In addition, in the first and second aspects of the invention, the cooling substrate is provided with each semiconductor power switch of the inverter circuit, the power capacitor for smoothing the battery supply current, and the DC-D for driving the vehicle electric load.
If a C converter etc. is installed, a power capacitor and DC
-These cooling can be satisfactorily performed without adding a cooling device for the DC converter. It is possible to add an air-cooled cooling board as a cooling device for the power condenser and the DC-DC converter, but it is necessary to separately install a cooling fan, a duct, and a cooling board with cooling fins. Will increase, resulting in an increase in weight. Further, although it is possible to add a liquid cooling type cooling board as a cooling device for the power condenser and the DC-DC converter, it is necessary to separately install and connect a pipe and an additional cooling board, and thus a narrow engine. Positioning in the room becomes complicated and the weight increases.

According to this structure, the cooling board as the heat sink of the semiconductor power switch absorbs a large amount of heat generated by the starting current, and therefore has a sufficient margin for the heat generated during normal running. Even if a DC-DC converter and a power capacitor, which do not increase current and heat generation, are additionally provided on the cooling substrate, the heat sink function of the semiconductor power switch during motor startup is hardly deteriorated. That is, when the power capacitor, the DC-DC converter, and the semiconductor power switch are mounted on the same cooling board, the cooling of the semiconductor power switch is hardly impeded.
It is possible to reduce the size and weight of the entire drive current control device and the number of parts.

Further, the both ends of the power capacitor and the DC-DC converter may be connected by extending the copper bar (power wiring) for connecting each semiconductor power switch of the inverter circuit on the cooling substrate, and slightly connecting to DC. Only the low-voltage output terminal of the DC converter needs to be added, and the terminal structure and wiring on the cooling board are not complicated.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, reference numeral 1 is a main battery, and 12 is a controller, which is housed in a passenger compartment C of an electric vehicle EC. Reference numeral 2 is a drive motor (hereinafter referred to as motor), 3 is a power control unit that controls the power supplied to the motor 2, 4 is a pump for circulating cooling water, and 5 is a radiator for radiating cooling water. It is housed in the engine room E.

The pump 4 is driven by a built-in motor (not shown), sucks cooling water from the radiator 5, circulates the electric power control unit 3, the motor 2, and the radiator 5 in this order, and the cooling water cooled by the radiator 5 Cools the power control unit 3 and the motor 2 in order. The pump 4 and the radiator 5 constitute a liquid cooling device according to the present invention together with piping for connecting them. Further, the liquid cooling device and the electric power control unit 3 constitute a drive control device according to the present invention.

Next, the electric circuit of this electric vehicle will be described with reference to FIG. The high level terminal and the ground terminal of the battery 1 are individually connected to the high level DC input terminal 3a and the ground terminal 3b of the power control unit 3 through the high level line HL and the ground line LL, and the pair of DC output terminals 6a of the rectifier 60 are connected. , 6b are individually connected. The rectifying device 6 includes a transformer 61 that boosts commercial AC 100V power input from the commercial power source 60 to a predetermined voltage, an SCR circuit 62 that rectifies the secondary voltage of the transformer 61, and a predetermined value based on the magnitude of the battery voltage. The phase control circuit 63 controls the turn-on period of the SCR circuit 62 so that the level becomes a level. The AC input terminals 6c and 6d of the rectifier 60 are of a plug type that can be connected to and disconnected from the commercial power source 60.

The power control unit 3 in this embodiment has a copper bar (or a thick insulating coated copper cable) 91 having one end connected to the high-level DC input terminal 3a and a copper bar having one end connected to the ground terminal 3b. (Or a thick insulation-coated copper cable may be used) 92, and the U-phase inverter circuit 32, the V-phase inverter circuit 33, and the W-phase inverter circuit 34 in which the high-order output terminal and the ground terminal are individually connected between the copper bars 91 and 92. And a power capacitor 31 for absorbing ripple current connected between the copper bars 91 and 92, and a DC-DC converter 3 having a pair of DC input terminals connected between the copper bars 91 and 92.
5 and a cooling board 36 and a case 37 (see FIG. 3), which will be described later, on which they are mounted.

Each phase inverter circuit 32-34 includes a pair of npn bipolar power transistors (IGBTs).
Etc. may be used), and the three-phase inverter circuit 30 is configured as a whole. The output ends of the inverter circuits 32 to 34 of the respective phases are fed to the motor 2 through the output terminals 3U, 3V and 3W, and the motor 2 drives the left front wheel 8a and the right front wheel 8b through the speed reducer 7.

The DC-DC converter 35 is the battery 1
DC voltage (here, set to 200V) of D
It is a well-known circuit that reduces the voltage to C voltage (here, 12 V), and its output DC voltage is supplied to the low voltage power line ML of the vehicle through the output terminal 3c of the power control unit 3. The DC-DC converter 35 constantly or as needed monitors the voltage value of the low-voltage power supply line ML and has a function of maintaining the voltage value of the low-voltage power supply line ML within a predetermined range.

Between the low-voltage power supply line ML and the ground line LL, an electric load 13 for the vehicle, a low-voltage battery 10 for supplying the electric load to the vehicle, and a controller 12 are connected, and the controller 12 is based on the pedaling amount of the accelerator 11. The inverter circuits 32 to 34 for each phase are intermittently controlled to supply the three-phase AC power according to the accelerator pedal depression amount to the motor 2.
Drives left and right front wheels 8a, 8b (see FIG. 2) through the reduction mechanism 7.

As a result, the vehicle speed can be controlled according to the depression amount of the accelerator 6. A partially omitted perspective view of the power control unit 3 is shown in FIG. FIG. 3 illustrates a state in which the top plate and the front plate of the metal long rectangular box-shaped case 37 are omitted. The cooling board 36 is housed in the case 37. The cooling board 36 is a main portion 36a made of a long thick copper plate.
And a pipe joint base 36b extending from one end in the lengthwise direction at a right angle to the lengthwise direction. A cooling pipe 40 for water supply and a cooling pipe 41 for drainage penetrate through the side plate 37a of the case 37, and the tips of the cooling pipe 40 and the drainage cooling pipe 41 are respectively provided on the base portion 36b of the cooling substrate 36. The suction hole and the drain hole (not shown) are connected by welding or the like.

The output terminals 3U, 3V, 3W project from the side plate 37a of the case 37 while being electrically insulated. Similarly, the output terminal 3U, 3V, 3W protrudes from the side plate 37b of the case 37 to the input terminal 3.
a, 3 and the output terminal 3c (not shown) project while being electrically insulated. The inverter circuits 32 to 34 of each phase are mounted in a line in the lengthwise direction on the front main surface of the cooling board 36, and the DC-DC converter 35 and the power capacitor 35 are mounted on the rear main surface of the cooling board 36. 31 are placed in a line in the lengthwise direction.

FIG. 4 shows a cross-sectional view of the power control unit 3 taken along the line AA. In the cooling substrate 36, four cooling liquid passages 36c, one end of which is connected to the cooling pipe 40, and four cooling liquid passages 36d, one end of which are connected to the cooling pipe 41, are bored in the longitudinal direction. The other ends of the cooling liquid passages 36c and 36d are communicated with each other by a communication hole (not shown). Coolant passage 36
Cooling water is supplied to the c and 36d by the pump 4 when the motor 2 is driven and is cooled.

The V-phase inverter circuit 33 whose cross section is shown in FIG. 4 has a base 33a made of a copper plate.
A ceramic substrate (for example, an alumina substrate) 33b having a good heat transfer property is bonded onto the surface a. Ceramic substrate 33
A high-side transistor (semiconductor power switch in the present invention) 33c and a low-side transistor (semiconductor power switch in the present invention) 33d are provided on the surface b, and the ceramic substrate 33b and the transistor are further provided. 33c and 33d are protected by a metal cover 33e.

Of course, the other inverter circuits 32 and 34 have the same structure. On the other hand, DC- whose cross section is shown in FIG.
The DC converter 35 also has a base 35a made of a copper plate, and a ceramic substrate (for example, an alumina substrate) 35b having good heat conductivity is bonded onto the base 35a. A plurality of transistors (only one is shown here) 35c and a transformer 35 are provided on the ceramic substrate 35b.
d is provided, and further, these ceramic substrates 3
5b, the transistor 35c and the transformer 35d are protected by a metal cover 35e. The copper bar 91,
The illustration of 92 is omitted. The bases 33a and 35a are joined to the cooling substrate 36 with an adhesive or screws.
FIG. 5 shows a cross-sectional view of the power control unit 3 in the portion where the power capacitor 31 is present.

The power control unit 3 of the present embodiment having the above-mentioned structure has the following effects. First, since the cooling substrate 36 is liquid-cooled, the radiation fin for air cooling is not required. Further, the thermal resistance between the cooling substrate 36 and the cooling water in the cooling passages 36c and 36d is the cooling air and the cooling substrate 3 in the air cooling type.
6, the specific heat of water is much smaller than that of the cooling board, and the specific heat of water is much larger than that of the cooling board. Therefore, even if the cooling board 36 is made significantly smaller and lighter, its heat sink function can be maintained.

Further, since the thickness direction of the cooling substrate 36 is arranged in the engine room E so as to be substantially coincident with the vehicle front-rear direction, the collision energy at the time of a collision is kept in the engine room E.
The cooling board 36 does not become an obstacle when absorbing by the crash of the front part of the vehicle body. Further, even if the partition wall between the engine room E and the passenger compartment C is damaged, the cooling board 36 does not jump into the passenger compartment and cause damage to passengers.

Further, in the present embodiment, the DC-DC converter 35 for charging the power capacitor 31 for smoothing the battery supply current and the battery 10 for feeding the vehicle electric load 13 is charged.
However, since it is mounted on the cooling board 36, it is not necessary to separately install a cooling board for liquid cooling of the power capacitor 31 and the DC-DC converter 35, and a cooling pipe is jointed to these additional cooling boards. It is possible to save time and labor and to reduce the weight of the cooling substrate and the piping system.

Since the cooling board 36 having a heat sink function at the time of starting the motor 2 of the inverter circuits 32 to 34 has a sufficient margin for heat generation during normal traveling,
Even if the DC-DC converter 35 for charging, which does not increase current and heat even when the motor 2 is started, is additionally provided on the cooling board 36, there is no problem in cooling the inverter circuits 32 to 34 when the motor is started. . In addition, since the power capacitor 31 does not increase in current or heat even when it is started, there is no problem in cooling the inverter circuits 32 to 34 when the motor is started.

Further, the power capacitor 31 and DC-DC
Each end of the converter 35 has inverter circuits 32-34.
It suffices to extend the copper bars 91, 92 for connecting the cables by a necessary length and connect the copper bars 91, 92 to each other.
There is no need to newly install many terminals. In this way, the power capacitor 31 and the DC-DC converter 3
5 can be satisfactorily cooled, and the life of the transistor of the DC-DC converter 35 and the power capacitor 31 can be extended.

In the above embodiment, both the power capacitor 31 and the DC-DC converter 35 are mounted on the cooling board 36, but it goes without saying that either one may be mounted. Further, a rectifying device (charger) for charging the battery may be mounted on the cooling board 36, and a long thick aluminum plate may be used as the cooling board 36.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an electric vehicle according to the present invention.

FIG. 2 is an electric circuit diagram of the electric vehicle of FIG.

3 is a perspective view of the power control unit of FIG. 1. FIG.

4 is a cross-sectional view taken along the line AA of FIG.

5 is a cross-sectional view of FIG.

[Explanation of symbols]

 1 Battery 2 Traveling Motor 4 Pump (Liquid Cooling Device), 5 Radiator (Liquid Cooling Device) 30 Inverter Circuit 31 Power Capacitor 33c Transistor (Semiconductor Power Switch) 33d Transistor (Semiconductor Power Switch) 35 DC-DC Converter 36 Cooling Substrate 36c Cooling Liquid passage 36d Cooling liquid passage C Car room E Engine room

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Sekimori 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Ryoji Oki 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Kosuke Suzui 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd.

Claims (4)

[Claims] 1. A cooling substrate made of a thick metal plate and arranged in a drive device storage chamber in front of or behind a vehicle compartment of an electric vehicle, and a plurality of semiconductors for intermittently controlling a current supplied from a battery to supply electric power to a traveling motor. An inverter circuit having an electric power switch and mounted on the cooling board, wherein the cooling board is arranged in the drive device accommodating chamber in a posture in which a plate thickness direction thereof substantially coincides with a vehicle front-rear direction. A drive device for an electric vehicle characterized by the above. 2. A cooling board which is made of a thick metal plate and is arranged in a drive device housing chamber in the front or rear of a vehicle compartment of an electric vehicle, and a plurality of semiconductors for intermittently controlling a current supplied from a battery to supply electric power to a traveling motor. An inverter circuit having a power switch and mounted on the cooling substrate, wherein the cooling substrate has a hollow structure. 3. The cooling circuit is provided with at least one of a battery supply current smoothing voltage capacitor and a vehicle electric load driving DC-DC converter together with the inverter circuit, and these are DC input of the inverter circuit. The drive device for an electric vehicle according to claim 1, wherein the drive devices are connected in parallel between the ends. 4. The drive device for an electric vehicle according to claim 1, wherein the cooling substrate has a cooling liquid passage through which a cooling liquid circulates, and the cooling liquid passage has a hollow structure.