JP5233795B2 - Control device for hybrid system - Google Patents

Description

  The present invention relates to a control device for controlling a hybrid system using, for example, a motor and an engine as drive sources.

  As is well known, this type of hybrid system includes an engine, a vehicle drive motor, and a power storage device (hereinafter also simply referred to as “battery”) for supplying power to the vehicle drive motor. All of these are hindered in operation when the temperature rises, and are cooled by an appropriate method. On the other hand, when the temperature of the battery is lower than a predetermined temperature, the operation efficiency of the battery is deteriorated. That is, it can be said that the battery has a unique driving temperature band that can be appropriately used.

  In order to cope with such a problem, that is, to ensure a suitable operation even at a low temperature, a technique for heating the battery at a low temperature or a technique for using a power source other than the battery at a low temperature has been proposed. . For example, techniques disclosed in the following Patent Documents 1 to 3 have been proposed.

  Patent Document 1 proposes heating the battery by conducting heat of the refrigerant to the battery via a waterproof sheet. Patent Document 2 proposes that heat harmful to the function of the device generated by a device such as a drive motor or a brake for driving an automobile is used as a heat source for heating the battery. Patent Document 3 proposes switching between thermal connection / disconnection between the battery and the engine in accordance with the temperatures of a plurality of terminals in the battery.

  In addition, Patent Documents 4 and 5 propose techniques related to the present invention. Patent Document 4 proposes a technology that utilizes exhaust heat (waste heat) of a travel motor in a hybrid vehicle for heating a heat engine. Patent Document 5 proposes a technique for quickly increasing the temperature of a lubricating medium used in a transmission.

JP 2008-290636 A Japanese Patent Laid-Open No. 7-329581 JP 2008-279878 A JP 2006-321389 A JP 2006-288141 A

  However, the above-described Patent Documents 1 to 5 do not describe efficient use of exhaust heat of the engine and the motor to efficiently heat and retain the battery in the hybrid system.

  The present invention has been made to solve the above-described problems, and is a controller for a hybrid system that can efficiently heat and retain a battery by appropriately using exhaust heat of an engine and a motor. The purpose is to provide.

  In one aspect of the present invention, a control device of a hybrid system includes: a first connection means that thermally connects a battery that transfers power to and from the motor; and the engine; and the battery and the motor. A second connection means for thermal connection; a first switching means for switching thermal connection / disconnection between the battery and the engine by the first connection means; and the battery by the second connection means. Second switching means for switching between thermal connection / disconnection with the motor, temperature detection means for detecting the temperature of one or more terminals provided in the battery, temperature detected by the temperature detection means, and Switching control means for controlling switching of the first switching means and the second switching means in accordance with a travel mode in the hybrid system , Comprising a.

  The above hybrid system control device is preferably applied to a hybrid system using a motor and an engine as drive sources. The first connecting means thermally connects the battery and the engine, and the second connecting means thermally connects the battery and the motor. The first switching means switches thermal connection / disconnection between the battery and the engine by the first connection means, and the second switching means switches thermal connection / non-connection between the battery and the motor by the second connection means. Switch connection. The temperature detection means detects the temperature of one or more terminals provided in the battery. The switching control unit performs switching control for the first switching unit and the second switching unit according to the temperature detected by the temperature detection unit and the travel mode in the hybrid system. This makes it possible to efficiently heat and keep the battery warm.

It is a schematic diagram which shows the basic composition of the hybrid system which concerns on embodiment of this invention, and the hybrid system which is the control object. It is a schematic diagram which shows the temperature adjustment mechanism of the hybrid system which concerns on embodiment. It is a schematic diagram which shows the specific example of the selective heat conduction mechanism of the hybrid system which concerns on embodiment. It is a flowchart which shows operation | movement of the control apparatus of the hybrid system which concerns on embodiment.

Preferred embodiments of the present invention will be described below with reference to the drawings.
[Device configuration]
First, the configuration of the control device of the hybrid system according to the present embodiment will be described with reference to FIGS. 1 to 3.

  With reference to the block diagram of FIG. 1, a hybrid system control device according to an embodiment of the present invention and a hybrid system that is a control target thereof will be described.

  In FIG. 1, the hybrid system 10 includes an ECU (Electronic Control Unit) 100, an engine 200, a motor MG1, a motor MG2, a power split mechanism 300, an inverter 400, a battery 500, and a battery sensor 501, via the transmission mechanism 21. This is a system for driving the wheels 22 of the hybrid vehicle 20.

  The ECU 100 is a specific example of a part of the “switching control unit” according to the present invention, and is configured to function as an electronic control unit that controls the entire operation of the hybrid system 10. Specifically, the ECU 100 is configured as a logical operation circuit centered on a read-only memory (Read Only Memory: ROM) storing a control program and an occasional write-read memory (Random Access Memory: RAM) storing various data. Has been. And it is electrically connected to the input port which receives an input signal from various sensors, and the output port which sends a control signal to various actuators with which engine 200, inverter 400, motor MG1, MG2, etc. are equipped.

  The engine 200 is an internal combustion engine that outputs motive power by combustion of fuel such as gasoline. Operation control such as fuel injection control, ignition control, intake air amount adjustment control, etc. is performed by the ECU 100 that receives signals from various sensors that detect operating conditions. Is receiving.

  Motor MG1 and motor MG2 are configured as well-known synchronous generator motors that operate under the control of ECU 100, and exchange power with battery 500 via inverter 400. The power line connecting inverter 400 and battery 500 is configured as a positive bus and a negative bus shared by inverter 400, and consumes power generated by at least one of motor MG1 and motor MG2. It is possible. Therefore, the battery 500 is charged and discharged by the electric power generated from the motor MG1 and the motor MG2 or insufficient electric power.

  Hereinafter, when referring to both the motor MG1 and the motor MG2, and when the motor MG1 and the motor MG2 are used without being distinguished from each other, they are referred to as “motor MG”.

  The power split mechanism 300 employs, for example, a planetary gear. The rotating shaft of the planetary carrier in the gear mechanism is connected to the engine 200 and transmits power to the outer ring gear and the inner sun gear through the pinion gear. The ring gear rotation shaft is directly connected to motor MG2 and transmits driving force to hybrid vehicle 20, and the sun gear rotation shaft is connected to motor MG1.

  The transmission mechanism 21 is connected to the rotating shaft of the ring gear of the power split mechanism 300 and is configured to be able to transmit driving force to the wheels 22.

  Inverter 400 is configured to perform AC-DC conversion of electric power, and mediates transfer of electric power between battery 500 and motor generator MG1 and motor MG2.

  Battery 500 is a rechargeable storage battery configured to be able to drive motor generator MG1 and motor MG2 when driven.

  The battery sensor 501 calculates the remaining capacity (State Of Charge: SOC) based on the integrated value of the charge / discharge current detected by the current sensor in order to manage the battery 500. In addition, the battery 500 is provided with various sensors (see FIG. 2), and outputs data related to the state of the battery 500 to the ECU 100 by communication as necessary.

  Next, a temperature adjustment mechanism of the hybrid system 10 according to the embodiment will be described with reference to the schematic diagram of FIG. FIG. 2 is a diagram for explaining in detail the battery 500 and the engine 200 in the hybrid system 10 shown in FIG. In FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

  As shown in FIG. 2, the temperature adjustment mechanism of the hybrid system 10 according to the embodiment includes a battery 500, an engine 200, a motor MG, heating media 730 and 735, and temperature detection units 610, 615, 620, and 630. The selective heat conduction mechanism and the ECU 100 are included.

  The battery 500 includes an electrode body 540 accommodated in the battery case 530, and a positive electrode connection terminal 510 and a negative electrode connection terminal 520 that are joined to the electrode body 540 and extend inside and outside the battery case 530. .

  The electrode body 540 has a specific temperature band (in other words, “driving temperature band”) in which the operation efficiency can be maintained at a certain level or higher. The electrode body 540 is not particularly limited as long as it is a power storage element capable of storing and releasing predetermined power, but the shape and size of the electrode body are not particularly limited, and can be configured in a desired form and size. Typical examples include well-known all-solid-state batteries, various forms of primary batteries (eg, lithium primary batteries, manganese batteries), secondary batteries (eg, lithium secondary batteries, nickel metal hydride batteries), or capacitors (eg, electric double layers). Capacitor). Among them, the all-solid-state battery using the solid electrolyte has good thermal conductivity, good output characteristics in the high temperature range, good deterioration resistance in the high temperature range, etc. Particularly preferred.

  The battery case 530 has a rectangular parallelepiped flat box structure made of, for example, a polypropylene resin, which is a thermoplastic resin, and has a housing portion for the electrode body 540 therein. Thereby, the electrode body 540 is physically protected, and deformation or breakage due to stress from the outside can be prevented. Polypropylene resin is preferably applied to this type of battery because it is excellent in adhesion to a laminate film used for sealing the battery and has rigidity. In addition, polystyrene resin, polyethylene resin, and the like can also be used.

  The positive electrode connection terminal 510 is a thin long plate member made of, for example, aluminum. The negative electrode connection terminal 520 is, for example, a thin long plate member made of copper. The bipolar connection terminals are fixed to the battery case 530 by insert molding when the battery case 530 is injection molded.

  The heat medium 730 is, for example, cooling water, and is thermally connected to the engine 200. For example, the heat medium 730 circulates inside the engine 200 that has become high temperature during combustion, thereby cooling the engine 200. The heat medium 730 heated by the engine 200 is supplied to a radiator (not shown) and cooled, and the cooled heat medium 730 is sent to the engine 200 again.

  The heat medium 735 is, for example, cooling water and is thermally connected to the motor MG. Then, for example, the motor MG is cooled by circulating the heat medium 735 through the motor MG that has become hot due to operation. Note that the heat medium 735 is thermally connected to one of the motor MG1 and the motor MG2, or both the motor MG1 and the motor MG2.

  The temperature detection units 610, 615, 620, and 630 are specific examples of the “temperature detection unit” according to the present invention, and are, for example, a platinum resistance thermometer, a thermistor, or a thermocouple type temperature sensor. The temperature detection unit 610 is the temperature T3 of the heat medium 730, the temperature detection unit 615 is the temperature T4 of the heat medium 735, the temperature detection unit 620 is the temperature T2 of the positive electrode connection terminal 510, and the temperature detection unit 630 is the temperature of the negative electrode connection terminal 520. The temperature T1 is detected, and the result is transmitted to the ECU 100.

  The heat medium 730 and the battery 500 can selectively exchange heat with each other by a selective heat conduction mechanism. The selective heat transfer mechanism includes a heat conductor 720 which is a specific example of the “first connection unit” according to the present invention and a switch 710 which is a specific example of a part of the “first switching unit” according to the present invention. And comprising. The heat conductor 720 is made of, for example, a heat conductive material such as metal, and is configured such that one end is in contact with the heat medium 730 and the other end is in selective contact with the positive electrode connection terminal 510 (or the negative electrode connection terminal 520). As shown by an arrow A1 in FIG. 2, the thermal connection state of the two can be adjusted by turning on (connected) / off (not connected) a switch 710. Switch 710 is controlled by ECU 100.

  The heat medium 735 and the battery 500 can selectively exchange heat with each other by a selective heat conduction mechanism. The selective heat conduction mechanism includes a heat conductor 725 which is a specific example of the “second connection unit” according to the present invention and a switch 715 which is a specific example of a part of the “second switching unit” according to the present invention. And comprising. The heat conductor 725 is made of, for example, a heat conductive material such as metal, and is configured such that one end is in contact with the heat medium 735 and the other end is selectively in contact with the positive electrode connection terminal 510 (or the negative electrode connection terminal 520). As indicated by an arrow A2 in FIG. 2, the thermal connection state between the two can be adjusted by turning on (connected) / off (not connected) a switch 715. Switch 715 is controlled by ECU 100.

  Here, a specific example of the selective heat conduction mechanism will be described with reference to FIG. FIG. 3 shows only a selective heat conduction mechanism that transfers heat between the heat medium 730 and the battery 500 for convenience of explanation. Note that the configuration shown in FIG. 3 is naturally applicable to a selective heat conduction mechanism that transfers heat between the heat medium 735 and the battery 500.

In the specific example of the selective heat conduction mechanism shown in FIG. 3, a piezoelectric element 721 is used as the heat conductor 720. The piezoelectric element 721 includes a metal plate 7211 fixed to the heat medium 730 at one end and a metal plate 7212 at the other end. A lead wire 7213 electrically connected to both ends of the piezoelectric element 721 is further connected to the switch 710. When the switch 710 is turned on and the piezoelectric element 721 to which a voltage is applied extends a predetermined amount, the heat medium 730 and the positive electrode connection terminal 510 (or the negative electrode connection terminal 520) are thermally connected. On the other hand, when the switch 710 is turned off and the piezoelectric element 721 contracts by a predetermined amount, the heat medium 730 and the positive electrode connection terminal 510 (or the negative electrode connection terminal 520) are thermally disconnected, that is, thermally disconnected. Is done. In addition, in the specific example of the selective heat conduction mechanism shown in FIG. 3, the battery case 530 is accommodated by the heat insulating material 550. Thereby, useless heat dissipation from the electrode body 540 is suppressed, and thermal deterioration of an external member can be prevented together with a heat retaining effect.
[Operation method]
Next, a specific operation of the control device of the hybrid system 10 according to the present embodiment configured as described above will be described.

  In the present embodiment, the ECU 100 uses the exhaust heat of the engine 200 in accordance with the temperatures T1 to T4 described above and the travel modes (engine travel mode, HV travel mode, EV travel mode) in the hybrid system 10. And heating of the battery 500 using the exhaust heat of the motor MG are switched. Specifically, the ECU 100 turns on / off the switch 710 and the switch 715 based on the temperature T3 of the heat medium 730, the temperature T4 of the heat medium 735, the temperature T2 of the positive electrode connection terminal 510, and the temperature T1 of the negative electrode connection terminal 520. By controlling OFF, heating by the heat medium 730 via the heat conductor 720 and heating by the heat medium 735 via the heat conductor 725 are switched. By doing so, it is possible to efficiently heat and keep the battery 500 warm.

  In the following description, the switch 710 is referred to as “switch 1”, and the switch 715 is referred to as “switch 2”.

  FIG. 4 is a flowchart illustrating an operation example of the control device of the hybrid system 10 according to the embodiment. In the flowchart, basically, processing is performed to maintain the temperature of the battery 500 at a temperature between the lower limit value Ta of the driving temperature band of the battery 500 and the upper limit value Tb of the driving temperature band.

  In FIG. 4, when starting the hybrid system 10, the engine 200 is turned on (step S100). Then, the ECU 100 turns on the switch 1 (step S101). Thereby, the heat medium 730 and the positive electrode connection terminal 510 are thermally connected via the heat conductor 720. Subsequently, the temperature detection unit 630 detects the temperature T1 of the negative electrode connection terminal 520 that is considered to be lower in temperature than the positive electrode connection terminal 510 because it is far from the heat conductor 720. In response to the result, ECU 100 determines whether or not “T1 <Ta” (step S102). When it is determined that “T1 <Ta” (step S102: Yes), that is, when the entire battery 500 has not yet reached the driving temperature band, the traveling mode of the hybrid system 10 is set to heat the battery 500. The “engine running mode” is set (step S103). Thereby, the temperature of engine 200 is increased by combustion, and electrode body 540 of battery 500 is heated via heat conductor 720.

  On the other hand, when it is determined that “T1 <Ta” is not satisfied, or when the electrode body 540 is heated until it is determined that “T1 ≧ Ta” as a result of heating as described above (step S102: No). ) Since the entire battery 500 has reached the drive temperature band, the travel mode of the hybrid system 10 is set to the “HV travel mode” (step S104). That is, the wheels 22 of the hybrid vehicle 20 are driven by the engine 200 and the motor MG2. Subsequently, whether or not the vehicle is traveling at a high load is determined by detecting the intake air amount of the engine 200, for example (step S105). Here, when it is not determined that the vehicle is traveling at a high load (step S105: No), that is, when the vehicle is traveling at a low load, the traveling mode of the hybrid system 10 is set to “EV traveling mode” using only the motor MG2 (step S106). ). Accordingly, engine 200 is turned off (step S107).

  Thereafter, the temperature detection unit 610 detects the temperature T3 of the flow path of the heat medium 730, and the temperature detection unit 620 detects the temperature T2 of the positive electrode connection terminal 510, respectively. In response to the result, the ECU 100 determines whether or not “T3 ≦ T2” is satisfied (step S109). When it is not determined that “T3 ≦ T2” is satisfied (step S109: No), heat is not released from the heated electrode body 540 to the heat medium 730 on the high temperature side. It is determined again whether or not the vehicle is loaded (step S105). On the other hand, when it is determined that “T3 ≦ T2” is satisfied (step S109: Yes), heat is radiated from the heated electrode body 540 to the heat medium 730 on the low temperature side. Therefore, the ECU 100 turns off the switch 1 to cut off the thermal connection (step S110).

  Subsequently, the temperature detection unit 615 detects the temperature T4 of the flow path of the heat medium 735, and the temperature detection unit 620 detects the temperature T2 of the positive electrode connection terminal 510, respectively. In response to the result, the ECU 100 determines whether or not “T4 ≦ T2” is satisfied (step S111). When it is determined that “T4 ≦ T2” is satisfied (step S111: Yes), the ECU 100 determines whether “T1 ≦ Ta or T2 ≦ Ta” is satisfied (step S112). In other words, it is determined whether or not the battery 500 has cooled below the driving temperature band. When it is determined that “T1 ≦ Ta or T2 ≦ Ta” (step S112: Yes), since the temperature of the battery 500 has cooled below the driving temperature band, the “EV traveling mode” is not preferable. Therefore, returning to the first step (return), the engine 200 is turned on (step S100). On the other hand, when it is not determined that “T1 ≦ Ta or T2 ≦ Ta” (step S112: No), it is considered that the temperature of the battery 500 is within the driving temperature band, so whether or not the vehicle is traveling at a high load. It is determined again (step S105).

  On the other hand, when it is not determined that “T4 ≦ T2” is satisfied (step S111: No), the ECU 100 turns on the switch 2 to heat the battery 500 by the motor MG (step S120). As a result, the heat medium 735 and the positive electrode connection terminal 510 are thermally connected via the heat conductor 725. Subsequently, the temperature detection unit 620 detects the temperature T2 of the positive electrode connection terminal 510. In response to the result, ECU 100 determines whether or not “T2 ≧ Tb” is satisfied (step S121). When it is not determined that “T2 ≧ Tb” is satisfied (step S121: No), it is considered that the temperature of the battery 500 does not reach or is within the driving temperature band. Therefore, while maintaining the thermal connection, “HV The “travel mode” is set (step S104).

  On the other hand, when it is determined that “T2 ≧ Tb” is satisfied (step S121: Yes), it is considered that the temperature of the battery 500 exceeds the driving temperature band, so that further heating causes the battery 500 to be thermally deteriorated. End up. Therefore, the ECU 100 turns off the switch 2 to cut off the thermal connection (step S122). Subsequently, the ECU 100 determines whether or not “T1 ≦ Ta or T2 ≦ Ta” is satisfied (step S123). In other words, it is determined whether or not the battery 500 has cooled below the driving temperature band. When it is determined that “T1 ≦ Ta or T2 ≦ Ta” (step S123: Yes), the temperature of the battery 500 has cooled down from the driving temperature band, so the process returns to the first step (return), and the engine 200 is turned on (step S100). On the other hand, if it is not determined that “T1 ≦ Ta or T2 ≦ Ta” (step S123: No), it is considered that the temperature of the battery 500 is within the driving temperature band, and therefore, the “HV traveling mode” is set. (Step S104).

  On the other hand, when it is determined that the vehicle is traveling at a high load (step S105: Yes), the “HV traveling mode” using not only the motor MG2 but also the engine 200 is maintained or switched to the “HV traveling mode”. (Step S130). Therefore, if engine 200 is off, it is turned on. Further, the temperature detection unit 620 detects the temperature T2 of the positive electrode connection terminal 510. In response to the result, ECU 100 determines whether or not “T2 ≧ Tb” is satisfied (step S133). Here, when it is not determined that “T2 ≧ Tb” is satisfied (step S133: No), it is considered that the temperature of the battery 500 does not reach or is within the driving temperature band, so that the thermal connection is maintained. Then, it is determined again whether or not the vehicle is traveling at a high load (step S105).

  On the other hand, when it is determined that “T2 ≧ Tb” is satisfied (step S133: Yes), it is considered that the temperature of the battery 500 exceeds the driving temperature band. End up. Therefore, the ECU 100 turns off the switch 1 to cut off the thermal connection (step S134). Subsequently, it is determined whether or not the vehicle is traveling at a high load (step S135). If it is determined that the vehicle is traveling at a high load (step S135: Yes), the “HV traveling mode” is maintained (step S136). Then, the ECU 100 determines whether or not “T1 ≦ Ta” (step S137). If it is not determined that “T1 ≦ Ta” (step S137: No), it is considered that the temperature of the battery 500 is within the driving temperature band, so whether the “HV traveling mode” is continuously maintained and the vehicle is traveling at a high load. It is determined again whether or not (step S135).

  On the other hand, when it is determined that “T1 ≦ Ta” is satisfied (step S137: Yes), the temperature of the battery 500 has cooled below the driving temperature band, so that the switch 1 is turned on and the battery is driven by the engine 200. 500 is heated (step S138), and then it is determined again whether the vehicle is traveling under a high load (step S105). On the other hand, when it is not determined that the vehicle is traveling at a high load (step S135: No), that is, when the vehicle is traveling at a low load, the traveling mode of the hybrid system 10 is switched to the “EV traveling mode” using only the motor MG2 (step S140). . Accordingly, engine 200 is turned off (step S141). Thereafter, the processing after step S112 described above is performed.

  As described above, according to the control device of the hybrid system 10 according to the present embodiment, the battery 500 is suitably heated until it reaches the driving temperature band, and the heated heat can now be suitably maintained. In addition, the temperature of the electrode body 540 is increased by heating the positive electrode connection terminal 510 having high heat conductivity (that is, the temperature of the electrode body 540 is increased via the positive electrode connection terminal 510 in contact with the electrode body 540). The heating effect of the electrode body 540 becomes higher than when the surface of the battery 500 is heated. In addition, since the surface temperature of the battery 500 is difficult to rise, thermal deterioration of surrounding members can be avoided.

  Furthermore, according to this embodiment, since the heating by the two types of heat mediums 730 and 735 is switched using the switches 710 and 715, the hybrid system 10 in this embodiment has a long EV travel distance (that is, the engine is operated). Even when applied to a plug-in hybrid vehicle or the like (which has a short time), the temperature of the battery 500 can be efficiently increased without being lowered.

10 Hybrid system 100 ECU
200 Engine 500 Battery 510 Positive electrode connection terminal 520 Negative electrode connection terminal 540 Electrode body 610, 615, 620, 630 Temperature detection unit 710, 715 Switch 721 Piezoelectric element 720, 725 Heat conductor 730, 735 Heat medium MG1, MG2 Motor

Claims (1)

A control device for controlling a hybrid system using a motor and an engine as drive sources,
A first connection means for thermally connecting a battery that exchanges power with the motor and the engine;
Second connection means for thermally connecting the battery and the motor;
First switching means for switching thermal connection / disconnection between the battery and the engine by the first connection means;
Second switching means for switching thermal connection / disconnection between the battery and the motor by the second connection means;
Temperature detecting means for detecting the temperature of one or more terminals provided in the battery;
Switching control means for controlling switching of the first switching means and the second switching means in accordance with the temperature detected by the temperature detection means and the travel mode in the hybrid system. Control device for hybrid system.

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