JP2013218984A - Temperature control system, and drive system of hybrid construction machine provided with temperature control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature control system capable of improving the lifetime of a power storage device and a rotary electric machine, and a drive system of a hybrid construction machine provided with a temperature control system.SOLUTION: The temperature control system includes a circulation circuit 200 for circulating circulation liquid, a rotary electric machine 1 provided in the circulation circuit 200 to perform rotary driving, a radiator 205 provided in the circulation circuit 200 to radiate the heat of the circulation liquid heated by heat emitted from the rotary electric machine 1 to the outside, and a power storage device 4 provided in a branch path 215 branched from the circulation circuit 200 to store power by rotary driving of the rotary power machine 1 or feed the power to the rotary electric machine 1, supplies the circulation liquid radiated by the radiator 205 to the rotary electric machine 1 through the circulation circuit 200, and supplies the circulation liquid heated by the rotary electric machine 1 to the power storage device 4 through the branch path 215.

Description

  The present invention relates to a system for controlling the temperature of a power storage device such as a battery, and a drive system for a hybrid construction machine including the system.

  Patent Document 1 discloses a control system for a so-called hybrid construction machine that converts hydraulic energy of hydraulic oil (working fluid) discharged from an actuator into electric energy or kinetic energy.

JP 2002-275945 A

  Such a control system for a hybrid construction machine includes a rotating electrical machine and a power storage device (battery) connected to the rotating electrical machine, drives the rotating electrical machine with hydraulic energy of hydraulic oil, and charges the power storage device. The rotating electrical machine is driven by the electrical energy of the power storage device to convert it into hydraulic energy of hydraulic oil.

  The power storage device is a stack of a plurality of secondary battery cells, such as a lithium ion battery or a nickel metal hydride battery. Such a power storage device is desirably used in a predetermined temperature range. If the power storage device is used when the temperature of the power storage device is low and falls below a predetermined temperature range, the life of the power storage device may be shortened.

  The present invention has been made paying attention to such problems, and provides a temperature control system capable of improving the life of the power storage device and the rotating electrical machine, and a drive system for a hybrid construction machine including the temperature control system. For the purpose.

  The temperature control system according to the present invention includes a circulation circuit through which a circulating fluid circulates, a rotating electrical machine provided in the circulation circuit and rotationally driven, and provided in the circulation circuit and heated by heat generated from the rotating electrical machine. A radiator that dissipates the heat of the circulating fluid to the outside, and a power storage device that is provided in a branch path that branches from the circulation circuit, and that stores electricity by rotational driving of the rotating electrical machine, or supplies electric power to the rotating electrical machine. The circulating fluid radiated by the radiator is supplied to the rotating electrical machine via the circulating circuit, and the circulating fluid heated by the rotating electrical machine is supplied to the power storage device via the branch path. And

  According to the present invention, the circulating fluid radiated by the radiator is supplied to the rotating electrical machine via the circulating circuit, and the circulating fluid heated by the rotating electrical machine is supplied to the power storage device via the branch circuit. As a result, the rotating electrical machine is cooled by the circulating fluid, and the power storage device is heated by the circulating fluid. As a result, the power storage device and the rotating electrical machine can be used within a predetermined temperature range, and the lifespan of the power storage device and the rotating electrical machine can be improved.

It is a schematic block diagram of the fluid pressure control apparatus of the hybrid construction machine by embodiment of this invention. It is a schematic block diagram of the assist regeneration mechanism connected to the fluid pressure control apparatus by embodiment of this invention. It is a schematic block diagram of the temperature control system of the hybrid construction machine by embodiment of this invention. It is a flowchart explaining the control content of the temperature control unit by embodiment of this invention.

  Hereinafter, a hybrid construction machine according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a fluid pressure control device of a hybrid construction machine. The fluid pressure control device controls the operation of a hydraulic working machine such as a hydraulic excavator. This embodiment demonstrates the case where the expansion-contraction operation | movement of the boom cylinder 104 which drives the boom 101 (load) of the excavation attachment of a hydraulic shovel is controlled.

  The fluid pressure control system 120 discharges hydraulic oil to drive a boom cylinder 104 as an actuator, a pilot pump 109, a main control valve 110, a main passage 111, a first passage 112, a first passage, 2 passages 113 and a controller 114 are provided.

  The interior of the boom cylinder 104 is partitioned into a rod side pressure chamber 104a and a bottom side pressure chamber 104b by a piston rod 107 that slidably moves within the boom cylinder 104. The piston rod 107 is connected to the boom 101, and the boom 101 is driven when the piston rod 107 moves in the boom cylinder 104.

  The main pump 108 and the pilot pump 109, which are hydraulic sources, are driven by an engine (not shown) mounted on the hybrid construction machine, and discharge hydraulic oil (working fluid). The main pump 108 and the pilot pump 109 are variable displacement hydraulic pumps capable of adjusting the discharge amount of hydraulic oil by controlling the inclination angle of the swash plate. The engine is operated at a predetermined rotational speed and load with good operating efficiency.

  The hydraulic oil discharged from the main pump 108 is supplied to a main control valve 110 that switches between supplying and discharging hydraulic oil to and from the boom cylinder 104. The main pump 108 and the main control valve 110 are connected by a main passage 111. In addition to the hydraulic oil discharged from the main pump 108, hydraulic oil discharged from the assist pump 3 of the assist regeneration mechanism 10 (see FIG. 2) described later is guided to the main passage 111 through the sub passage 31.

  The main control valve 110 and the rod side pressure chamber 104a of the boom cylinder 104 are connected by a first passage 112, and the main control valve 110 and the bottom side pressure chamber 104b of the boom cylinder 104 are connected by a second passage 113. Connected to the second passage 113 is a return passage 21 through which hydraulic oil that is discharged from the bottom pressure chamber 104b of the boom cylinder 104 and that drives a regenerative motor 2 of an assist regenerative mechanism 10 (see FIG. 2) described later flows. The

  The main control valve 110 is operated by hydraulic pressure (pilot pressure) of hydraulic oil supplied from the pilot pump 109 to the pilot chambers 110a and 110b. Control of the pilot pressure supplied to the pilot chambers 110a and 110b is performed by the controller 114 controlling the pilot solenoid valve 115 based on a lever operation by the crew of the excavator.

  When pilot pressure is supplied to the pilot chamber 110a, the main control valve 110 is switched to the position a, and hydraulic oil is supplied from the main pump 108 to the rod side pressure chamber 104a via the first passage 112, and The hydraulic oil in the bottom side pressure chamber 104 b is discharged to the tank T through the second passage 113. Thereby, the piston rod 107 in the boom cylinder 104 moves downward in FIG. 1, that is, the boom cylinder 104 contracts and the boom 101 descends.

  When pilot pressure is supplied to the pilot chamber 110b, the main control valve 110 is switched to the position b, and hydraulic oil is supplied from the main pump 108 to the bottom pressure chamber 104b via the second passage 113, and The hydraulic oil in the rod side pressure chamber 104 a is discharged to the tank T through the first passage 112. As a result, the piston rod 107 in the boom cylinder 104 moves upward in FIG. 1, that is, the boom cylinder 104 extends and the boom 101 rises.

  On the other hand, when the pilot pressure is not supplied to the pilot chambers 110a and 110b, the main control valve 110 is switched to the position c, the supply and discharge of the hydraulic oil to the boom cylinder 104 is shut off, and the boom 101 is kept stopped.

  Thus, the main control valve 110 has three switching positions: a contracted position a for contracting the boom cylinder 104, an extended position b for extending the boom cylinder 104, and a blocking position c for holding the load of the boom cylinder 104. .

  The fluid pressure control device 120 according to the present embodiment includes a regenerative control that collects hydraulic energy of hydraulic oil discharged from the bottom-side pressure chamber 104b as electric energy as necessary when the boom cylinder 104 is contracted, and a boom. An assist regeneration mechanism 10 is provided that can execute assist control for applying an assisting force as necessary when the cylinder 104 is extended.

  FIG. 2 is a schematic configuration diagram of the assist regeneration mechanism 10 connected to the fluid pressure control device 120. The assist regeneration mechanism 10 includes a motor generator 1, a regeneration motor 2, an assist pump 3 that assists the driving of the boom cylinder 104 by the main pump 108, a battery 4, an inverter 5, a return passage 21, and a sub passage 31. .

  The motor generator 1 is a rotating electrical machine having a function as an electric motor that is driven by a battery 4 that is a power storage device to drive the assist pump 3 and a function as a generator that is driven by the regenerative motor 2 to generate electric power. The rotation shafts of the motor generator 1, the regenerative motor 2 and the assist pump 3 are arranged coaxially. When the rotation shaft of the motor generator 1 rotates, the rotation shafts of the regenerative motor 2 and the assist pump 3 rotate together. Similarly, when the rotating shaft of the regenerative motor 2 rotates, the rotating shafts of the motor generator 1 and the assist pump 3 rotate together.

  The regenerative motor 2 is a variable displacement hydraulic motor that can control the output torque by controlling the inclination angle of the swash plate. The regenerative motor 2 is driven by the hydraulic oil discharged from the bottom pressure chamber 104b of the boom cylinder 104 and flowing through the return passage 21. The inclination angle of the swash plate of the regenerative motor 2 is controlled by the inclination angle controller 24. The tilt angle controller 24 is controlled by the controller 114. By controlling the inclination angle of the swash plate of the regenerative motor 2, the capacity of the regenerative motor 2 changes, and the maximum value of the torque that can be generated by the regenerative motor 2 changes.

  The return passage 21 is provided with a return control valve 22 that switches between supply and discharge of hydraulic fluid to the regenerative motor 2. The return control valve 22 has a communication position d for supplying hydraulic oil to the regenerative motor 2 according to the pilot pressure supplied from the pilot pump 109 to the pilot chamber 22a, and a shut-off for stopping the supply of hydraulic oil to the regenerative motor 2. Switch to position e. Control of the pilot pressure supplied to the pilot chamber 22a is performed by the controller 114 controlling the pilot solenoid valve 23 based on a lever operation by the crew of the excavator.

  The assist pump 3 is a variable displacement hydraulic pump capable of controlling the discharge amount by controlling the inclination angle of the swash plate. The assist pump 3 is driven by the motor generator 1 and supplies hydraulic oil to the main passage 111 via the sub passage 31. The inclination angle of the swash plate of the assist pump 3 is controlled by the inclination angle controller 34. The tilt angle controller 34 is controlled by the controller 114. By controlling the inclination angle of the swash plate of the assist pump 3, the capacity of the assist pump 3 changes, and the maximum value of the flow rate of hydraulic oil that can be discharged by the assist pump 3 changes.

  The sub passage 31 is provided with a sub control valve 32 that switches supply and discharge of hydraulic oil to and from the main passage 111. The sub control valve 32 has a communication position f for supplying hydraulic oil to the main passage 111 according to the pilot pressure supplied from the pilot pump 109 to the pilot chamber 32a, and a cutoff for stopping the supply of hydraulic oil to the main passage 111. Switch to position g. Control of the pilot pressure supplied to the pilot chamber 32a is performed by the controller 114 controlling the pilot solenoid valve 33 based on a lever operation by the crew of the excavator.

  The motor generator 1 is connected to a battery 4 serving as a power source via an inverter 5. The battery 4 is configured by connecting a plurality of secondary battery cells such as chargeable / dischargeable lithium ion batteries in series. The power line 41 of the battery 4 and the inverter 5 is provided with a relay 42 for cutting off the electrical connection. The relay 42 is turned on and off by the controller 114.

  The inverter 5 is controlled by the controller 114 and converts direct current into alternating current or alternating current into direct current. Specifically, when the motor generator 1 is caused to function as an electric motor, the direct current from the battery 4 is converted into a three-phase alternating current having an arbitrary frequency and supplied to the motor generator 1. On the other hand, when the motor generator 1 functions as a generator, the three-phase alternating current from the motor generator 1 is converted into direct current and supplied to the battery 4.

  The operation of the fluid pressure control device 120 will be described with reference to FIGS. 1 and 2.

  First, regeneration by the assist regeneration mechanism 10 performed as necessary when the boom 101 (load) is lowered will be described. When a lever operation for contracting the boom cylinder 104 is performed by the crew of the hydraulic excavator, the main control valve 110 is switched to the contracted position a, and hydraulic oil is supplied to the rod side pressure chamber 104a and from the bottom side pressure chamber 104b. Hydraulic oil is discharged.

  At this time, when it is necessary to charge the battery 4, the return control valve 22 is switched to the communication position d, and a part of the hydraulic oil discharged from the bottom side pressure chamber 104 b is regenerated through the return passage 21. 2 is supplied. At the same time, the inclination angle of the swash plate of the assist pump 3 is controlled so that the capacity of the assist pump 3 is minimized.

  Thereby, since the rotating shaft of the motor generator 1 rotates in synchronization with the rotating shaft of the regenerative motor 2, the motor generator 1 can generate electric power, and the battery 4 can be charged. That is, hydraulic energy of the hydraulic oil discharged from the boom cylinder 104 can be converted into electric energy.

  On the other hand, when it is not necessary to charge the battery 4, the return control valve 22 is switched to the cutoff position e, and all the hydraulic oil discharged from the bottom side pressure chamber 104 b goes to the tank T through the second passage 113. Discharged.

  Next, the assist by the assist regeneration mechanism performed as necessary when the boom 101 (load) is raised will be described. When a lever operation for extending the boom cylinder 104 is performed by a crew member of the hydraulic excavator, the main control valve 110 is switched to the extended position b, the working oil is supplied to the bottom side pressure chamber 104b, and the rod side pressure chamber 104a The hydraulic oil is discharged to the tank T through the first passage 112.

  Here, the engine is operating at a predetermined rotational speed and load with good operating efficiency. Therefore, when it is desired to quickly extend the boom cylinder 104, the flow rate of hydraulic oil supplied to the bottom pressure chamber 104b may be insufficient with only the discharge amount by the driving force of the engine. In such a case, the assist regeneration mechanism 10 assists.

  Specifically, the battery generator 4 drives the motor generator 1 as an electric motor to drive the assist pump 3. Thereby, hydraulic fluid is discharged from the assist pump 3. As a result, the hydraulic oil discharged from the assist pump 3 can be joined to the main passage 111 via the sub passage 31 and an auxiliary force can be applied when the boom cylinder 104 is extended.

  The fluid pressure control device 120 having such an assist regeneration mechanism 10 includes a circulation circuit 200 through which a circulating fluid that can cool the motor generator 1 circulates, and the battery 4 using the circulating fluid warmed by the motor generator 1. It is configured to warm up. As described above, the hybrid construction machine includes the temperature control system that controls the temperature of the battery 4.

  FIG. 3 is a diagram showing a circulation circuit 200 through which the circulating fluid flows. The motor generator 1 and the inverter 5 shown in FIG. 3 are electric devices that are weak against heat and need to be cooled, and thus are cooled by the circulating fluid flowing through the circulation circuit 200. The motor generator 1 has a flow path 201 that circulates the circulating fluid around the heat generating portion, and a circulation circuit 200 is connected to the flow path 201. The inverter 5 also has a flow path 202 for circulating the circulating fluid around the heat generating portion, and the circulation circuit 200 is connected to the flow path 202.

  The circulation circuit 200 is provided with a pump 203, a tank 204 for storing the circulating fluid, and a radiator 205 as a radiator that radiates the heat of the circulating fluid to the outside. The circulation circuit 200 circulates the circulating fluid in the tank 204 through the flow path 202 of the inverter 5 and the flow path 201 of the motor generator 1 by driving the pump 203 to cool the inverter 5 and the motor generator 1, The heated circulating fluid is sent to the radiator 205 to dissipate heat and returned to the tank 204. An electric pump is used as the pump 203, and the pump 203 is driven by a power source different from the battery 4.

  If the battery 4 is used when the temperature falls below a predetermined temperature range, there is a risk that the life and efficiency will be reduced. Therefore, in the present embodiment, a temperature control unit 210 that controls the temperature of the battery 4 to a predetermined temperature range set in advance by using the heat of the circulating fluid that has been cooled and warmed by the motor generator 1 and the inverter 5 is provided. .

  The temperature control unit 210 includes a flow path 211 for warming the battery 4, a first connection path 212 that guides the circulating fluid in the circulation circuit 200 to the flow path 211 of the battery 4, and the circulating fluid that has passed through the flow path 211 of the battery 4. Are connected to the circulation circuit 200 from the flow path 211 of the battery 4, and a switching valve 214 provided between the motor generator 1 and the battery 4. Note that the flow path 211, the first connection path 212, and the second connection path 213 constitute a branch path 215 that branches from the circulation circuit 200. The circulating fluid heated by the motor generator 1 is supplied to the battery 4 via the branch path 215.

  The flow path 211 of the battery 4 is formed so as to surround the secondary battery cells constituting the battery 4.

  The first connection path 212 connects the flow path 211 of the battery 4 and the upstream circulation circuit 200 between the motor generator 1 and the radiator 205. The first connection path 212 is provided on the upstream side of the battery 4, connects the battery 4 and the switching valve 214, and supplies the circulating fluid heated by the motor generator 1 to the battery 4 via the switching valve 214. The second connection path 213 connects the flow path 211 of the battery 4 and the downstream circulation circuit 200 between the motor generator 1 and the radiator 205. The second connection path 213 is provided on the downstream side of the battery 4, connects the battery 4 and the radiator 205, and supplies the circulating fluid via the battery 4 to the radiator 205.

  The switching valve 214 has a valve opening position that allows the circulating fluid to flow from the upstream circulation circuit 200 between the motor generator 1 and the radiator 205 to the flow path 211 of the battery 4 through the first connection path 212, and the upstream side. A closed position where the circulating fluid is prevented from flowing from the circulation circuit 200 to the flow path 211 of the battery 4 through the first connection path 212. The switching valve 214 is disposed at a connection portion between the first connection path 212 and the circulation circuit 200, and constitutes a passage switching valve that selectively opens and closes the first connection path 212 side and the circulation circuit 200 side. The switching valve 214 switches the supply destination of the circulating fluid heated by the motor generator 1 to the circulation circuit 200 or the branch path 215.

  When the switching valve 214 is in the open state, the first connection path 212 side is opened and the circulation circuit 200 side is shut off. Thus, the circulating fluid that has been cooled by heating the motor generator 1 and the inverter 5 is supplied from the first connection path 212 to the flow path 211 of the battery 4 before being supplied to the radiator 205. When the switching valve 214 is in a closed state, the first connection path 212 side is blocked and the circulation circuit 200 side is opened. As a result, the circulating fluid that has been cooled by heating the motor generator 1 and the inverter 5 is supplied to the radiator 205 without flowing to the first connection path 212.

  As shown in FIG. 3, a battery temperature sensor 216 that detects battery temperature is installed in the battery 4, and a circulating fluid temperature sensor 217 that detects circulating fluid temperature is installed in the circulation circuit 200. Circulating fluid temperature sensor 217 is arranged in circulating circuit 200 downstream of motor generator 1 and between motor generator 1 and switching valve 214, and cools and warms circulating fluid that has been cooled by motor generator 1 and inverter 5. Detect temperature.

  The controller 114 (see FIG. 2) controls opening and closing of the switching valve 214 so as to maintain the battery temperature within a predetermined temperature range set in advance based on detection signals from the battery temperature sensor 216 and the circulating fluid temperature sensor 217.

  FIG. 4 is a flowchart for explaining the control contents of the controller 114 for the switching valve 214. This control is executed when the ignition key is turned on by the crew of the excavator.

  In step S1, the controller 114 reads detection signals from the battery temperature sensor 216 and the circulating fluid temperature sensor 217, and determines whether the battery temperature (reading temperature) is equal to or lower than the circulating fluid temperature (reading temperature).

  When the determination in step S1 is NO (battery temperature> circulating fluid temperature), the controller 114 closes the switching valve 214 in step S5. This prevents the battery 4 from being cooled by the circulating fluid having a temperature lower than the battery temperature.

  When the determination in step S1 is YES (battery temperature ≦ circulating fluid temperature), the controller 114 determines whether or not the battery temperature is equal to or lower than the lower limit temperature of the predetermined temperature range in step S2. When the determination in step S2 is YES (battery temperature ≦ the lower limit temperature of the predetermined temperature range), the controller 114 opens the switching valve 214 in step S3. As a result, the battery 4 is warmed by the circulating fluid at a temperature higher than the battery temperature, and the battery temperature rises above the lower limit temperature of the predetermined temperature range at an early stage.

  When the determination in step S2 is NO, the controller 114 determines whether or not the battery temperature is higher than the upper limit temperature in the predetermined temperature range in step S4. When the determination in step S4 is YES (battery temperature> the upper limit temperature in the predetermined temperature range), the controller 114 closes the switching valve 214 in step S5. This prevents the battery temperature from rising excessively.

  When the determination in step S4 is NO, the controller 114 opens the switching valve 214 in step S3. Thereby, the battery 4 is warmed by the circulating fluid having a temperature higher than the battery temperature.

  In the present embodiment described above, the circulating fluid radiated by the radiator 205 is supplied to the motor generator 1 via the circulation circuit 200, and the circulating fluid heated by the motor generator 1 is supplied to the battery 4 via the branch circuit 215. Supply. Thereby, motor generator 1 is cooled by the circulating fluid, and battery 4 is heated by the circulating fluid. As a result, the battery 4 and the motor generator 1 can be used within a predetermined temperature range, and the lifetime of the battery 4 and the motor generator 1 can be improved.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The temperature control system according to the present embodiment is configured to warm the battery 4 with the circulating fluid warmed by the motor generator 1 of the hybrid construction machine. However, the temperature control system is applied to an electric vehicle, an electric motorcycle, etc. You may comprise so that the battery of the said vehicle may be warmed with a circulating fluid.

  The switching valve 214 is a passage switching valve disposed at a connection portion between the first connection path 212 and the circulation circuit 200, but may be an on-off valve disposed in the middle of the first connection path 212.

  The second connection path 213 connects the flow path 211 for heating the battery 4 and the downstream circulation circuit 200 between the motor generator 1 and the radiator 205, but the flow path 211 of the battery 4, the radiator 205, and The tanks 204 may be connected to each other. Thereby, when the switching valve 214 is opened, the circulating fluid flows around the radiator 205, so that the temperature rise of the circulating fluid can be accelerated.

  In FIG. 3, the motor generator 1 and the inverter 5 are arranged in the circulating circuit 200 for circulating fluid. However, the present invention is not limited to this, and if there is another electric device that needs to be cooled, it may be added to the circulating circuit 200. Good.

  In the present embodiment, the assist regeneration mechanism 10 is applied to the fluid pressure control device 120 that drives the boom cylinder 104. However, the assist regeneration mechanism 10 drives the arm cylinder or bucket that drives the arm of the excavation attachment of the hydraulic excavator. The present invention may also be applied to a fluid pressure control device that drives a plurality of actuators such as a bucket cylinder that performs a traveling motor and a turning motor.

1 Motor generator
2 Regenerative motor 3 Assist pump (sub fluid pressure pump)
4 Battery 5 Inverter 108 Main pump (Main fluid pressure pump)
104 Boom cylinder (actuator)
114 controller 200 circulation circuit 201 flow path 202 flow path 203 pump 204 tank 205 radiator (radiator)
210 Temperature control unit 211 Flow path 212 First connection path 213 Second connection path 214 Switching valve 215 Branch path 216 Battery temperature sensor (power storage device temperature sensor)
217 Circulating fluid temperature sensor

Claims (6)

A circulation circuit through which the circulating fluid circulates;
A rotating electric machine provided in the circulation circuit and driven to rotate;
A radiator that is provided in the circulation circuit and radiates heat of the circulating fluid heated by heat generated from the rotating electrical machine to the outside;
A power storage device that is provided in a branch path that branches from the circulation circuit, stores electricity by rotational driving of the rotating electrical machine, or supplies electric power to the rotating electrical machine,
The circulating fluid radiated by the radiator is supplied to the rotating electrical machine via the circulating circuit, and the circulating fluid heated by the rotating electrical machine is supplied to the power storage device via the branch path. Temperature control system.   The switching valve which is provided between the rotating electrical machine and the power storage device and switches the supply destination of the circulating fluid heated by the rotating electrical machine to the circulation circuit or the branch path is provided. Temperature control system. The branch path is
A first connection path that is provided upstream of the power storage device, connects the power storage device and the switching valve, and supplies the circulating fluid heated by the rotating electrical machine to the power storage device via the switching valve; ,
A second connection path that is provided on the downstream side of the power storage device, connects the power storage device and the radiator, and supplies the circulating fluid that has passed through the power storage device to the radiator. The temperature control system according to claim 2. A power storage device temperature sensor that is provided in the power storage device and detects a temperature of the power storage device;
A circulating fluid temperature sensor that is provided on the downstream side of the rotating electrical machine and between the rotating electrical machine and the switching valve, and detects the temperature of the circulating fluid circulating in the circulation circuit;
The controller according to claim 2, further comprising: a controller that controls the switching valve to switch to the circulation circuit or the branch path based on detection results of the power storage device temperature sensor and the circulating fluid temperature sensor. 4. The temperature control system according to 3.   The controller controls the switching valve to switch to the branch path when the temperature of the power storage device is equal to or lower than the temperature of the circulating fluid and is outside a predetermined temperature range set in advance. The temperature control system according to claim 4. The temperature control system according to any one of claims 1 to 5,
A main fluid pressure pump that discharges the working fluid and drives the actuator;
A drive system for a hybrid construction machine, comprising: a sub fluid pressure pump coupled to the rotating electrical machine and assisting the drive of the actuator by the main fluid pressure pump.

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