JP2016119196A - Warming-up device for vehicular molten salt battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a warming-up device for a vehicular molten salt battery that efficiently raises the temperature of the molten salt battery without adding any heat source such as a heater, and also maintaining the temperature of the molten salt battery itself within an operational temperature range.SOLUTION: A warming-up device for a vehicular molten salt battery has: a main circulation passage (18) in which a working fluid circulates; a first heat exchanger (13) which heats the working fluid with a waste heat medium of an engine (2) of a vehicle (1); an expander (14) which expands the working fluid heated by the first heat exchanger to generate turning driving force; a second heat exchanger (15) which exchanges heat with the working fluid discharged from the expander; a condenser (16) which cools the working fluid discharged from the second heat exchanger; a pump (17) which sends the working fluid having been cooled by the condenser to the first heat exchanger; and the molten salt battery (40) which exchanges heat with the second heat exchanger to be warmed up to the operational temperature range.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a warming-up device for a molten salt battery for a vehicle, and more particularly to a technique for maintaining the operating temperature of a molten salt battery for a vehicle.

  In recent years, taking into consideration environmental problems and the like, development of hybrid electric vehicles using an engine and a motor as drive sources has been progressing. Such a hybrid vehicle is equipped with a large-capacity battery. However, if the battery is not within an appropriate temperature range, the charge / discharge efficiency is significantly reduced, and the life of the battery itself is shortened. In addition, the range of use of the hybrid system is limited, and the fuel efficiency improvement effect cannot be obtained.

  Therefore, for example, in a usage environment that is below freezing, such as in winter, it is necessary to warm up the battery temperature to a usable temperature range. For example, in Patent Document 1, a circulation path through which refrigerant circulates is formed in the vicinity of the engine and in the vicinity of the battery, and the battery is warmed up together with the warming up of the engine immediately after starting the vehicle.

  By the way, as a secondary battery used for a power source for driving a hybrid vehicle, a lithium ion battery, a nickel metal hydride battery, and the like have been conventionally known. However, in recent years, a high energy density and large capacity molten salt battery is used. Is being studied and researched and developed. For example, Patent Document 2 discloses mounting a molten salt battery on a vehicle.

JP 2006-151091 A JP 2012-174526 A

  However, such a molten salt battery has an operating temperature range that is relatively higher than that of a lithium ion battery, a nickel metal hydride battery, or the like. Therefore, although the cooling system can be simplified, the molten salt battery itself is at least within the operating temperature range. It is important to efficiently raise the temperature to the lower limit and maintain the temperature of the molten salt battery itself within the operating temperature range.

  The present invention has been made to solve such problems. The object of the present invention is to efficiently raise the temperature of the molten salt battery without adding a heat source such as a heater, and to improve the temperature of the molten salt battery itself. An object of the present invention is to provide a warm-up device for a molten salt battery for a vehicle that can maintain the temperature within an operating temperature range.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

  According to a first aspect of the present invention, there is provided a warm-up device for a molten salt battery for a vehicle mounted on a vehicle having an engine as a drive source, a main circulation passage through which a working fluid circulates, A first heat exchanger that heats the working fluid with a waste heat medium; an expander that expands the working fluid heated by the first heat exchanger to generate a rotational driving force; and a discharge from the expander. A second heat exchanger that exchanges heat with the working fluid; a condenser that cools the working fluid discharged from the second heat exchanger; and the working fluid cooled by the condenser is the first heat exchanger. A pump for sending to the heat exchanger; and a molten salt battery that exchanges heat with the second heat exchanger and is warmed up to an operating temperature range.

  In a second aspect, in the first aspect, a temperature detection unit that detects a temperature for detecting the temperature of the molten salt battery, and a secondary circulation that circulates the working fluid directly from the expander to the condenser And a warm-up control means for circulating the working fluid through the auxiliary circulation channel when the temperature of the molten salt battery is within an operating temperature range.

  According to a third aspect, in the first or second aspect, the warm-up control means does not pass through the second heat exchanger when the temperature of the molten salt battery is within an operating temperature range. The working fluid is circulated only through the auxiliary circulation channel.

  According to a fourth aspect, in the first or second aspect, the warm-up control means is on the main circulation flow path, between the expander and the second heat exchanger, and the second A flow control valve is provided between the heat exchanger and the condenser.

  According to the present invention using the above means, the temperature of the molten salt battery can be increased efficiently without adding a heat source such as a heater, and the temperature of the molten salt battery itself can be maintained within the operating temperature range.

It is a schematic structure figure of a hybrid vehicle carrying a warming-up device concerning one embodiment of the present invention. It is a schematic block diagram of the molten salt battery which comprises the warming-up apparatus which concerns on one Embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a hybrid vehicle equipped with a warm-up device according to an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of a molten salt battery configuring the warm-up device of the present invention. The present embodiment will be described with reference to the drawings.

  The hybrid vehicle 1 is composed of a so-called parallel type hybrid system, and is also simply referred to as a vehicle 1 in the following description.

  A vehicle 1 is equipped with a diesel engine (hereinafter referred to as an engine) 2 as a driving power source and a motor 3 (electric motor) that can also operate as a generator. A clutch 4 is connected to the output shaft of the engine 2, and an input side of the transmission 5 is connected to the clutch 4 via a rotating shaft of the motor 3. A differential device 7 is connected to the output side of the transmission 5 via a propeller shaft 6, and left and right drive wheels 9 are connected to the differential device 7 via a drive shaft 8.

  The engine 2 is provided with an exhaust gas pipe 11 for exhausting exhaust gas generated by combustion. The exhaust gas pipe 11 is provided with a waste heat recovery circuit 12 for recovering waste heat using the exhaust gas as a waste heat medium.

  As a specific configuration of the waste heat recovery circuit 12, the working fluid is expanded by the first heat exchanger 13 and the first heat exchanger 13 for heating the working fluid by the exhaust gas that is the waste heat medium of the engine 2. An expander 14 that generates a rotational driving force, a second heat exchanger 15 that exchanges heat with the working fluid discharged from the expander 14, a condenser 16 that cools the working fluid discharged from the second heat exchanger 15, A pump 17 is provided to send the working fluid cooled by the condenser 16 to the first heat exchanger. Here, the 1st heat exchanger 13 may be arrange | positioned so that the exhaust gas pipe 11 extended from the engine 2 may be adjoined, and may be arrange | positioned so that the outer peripheral part of the exhaust gas pipe 11 may be enclosed.

  Further, the waste heat recovery circuit 12 includes a main circulation channel 18 for circulating the working fluid in the order of the first heat exchanger 13, the expander 14, the second heat exchanger 15, the condenser 16, and the pump 17, expansion A sub-circulation passage 19 that circulates the working fluid directly from the condenser 14 to the condenser 16 without passing through the second heat exchanger 15 is provided. Further, a flow rate adjusting valve 20 is disposed in the main circulation channel 18 between the first heat exchanger 13 and the expander 14, and the main circulation channel between the expander 14 and the second heat exchanger 15. A bypass valve 21 is disposed at a branch portion between the second heat exchanger 15 and the auxiliary circulation channel 19, and a bypass valve 22 is disposed in the main circulation channel 18 between the second heat exchanger 15 and the condenser 16. .

  In the waste heat recovery circuit 12 in this embodiment, for example, alcohol can be used as the working fluid, but other optimal working fluid is used depending on the required waste heat recovery efficiency of the waste heat recovery circuit 12 or the like. be able to.

  Specifically, the motor 3 is a synchronous generator motor including a rotor on which a permanent magnet is attached and a stator on which a three-phase coil is wound. That is, the motor 3 can transmit the driving force to the transmission 5 instead of the engine 2, and further generates electric power by driving the engine 2 or reverse driving from the driving wheel side. Further, the motor 3 is connected to the power conversion device 31 via the wiring 30.

  The power conversion device 31 includes a general inverter and converter, and is connected to a battery 33 via a wiring 32 and further connected to a generator 35 via a wiring 34. That is, the power conversion device 31 is electrically connected to the motor 3, the battery 33, and the generator 35. Here, the generator 35 is connected to the expander 14 via the wiring 36, and generates power using the rotational driving force generated by the expander 14. Therefore, the power conversion device 31 can convert the DC power supplied from the battery 33 into AC power and supply it to the motor 3, and rectifies the AC power supplied from the motor 3 and the generator 35 to rectify the battery 33. Can be supplied.

  The battery 33 includes a molten salt battery 40, a temperature sensor (temperature detection unit) 41 that detects the temperature of the molten salt battery 40, and the second heat exchanger 15 disposed in the main circulation flow path 18 of the waste heat recovery circuit 12. have. In the present embodiment, in order to enable efficient supply of heat from the second heat exchanger 15 to the molten salt battery 40, the second heat exchanger 15 and the molten salt battery 40 are disposed adjacent to each other. . Here, the quantity of the molten salt battery 40 is not limited to one, and the quantity of the molten salt battery 40 can be changed as appropriate according to the amount of power required for the battery 33. For example, the battery 33 may include a series circuit in which a plurality of molten salt batteries 40 are connected, or one molten salt battery module including the plurality of molten salt batteries 40 and the second heat exchanger 15. Or you may provide two or more. The second heat exchanger 15 may be arranged outside the battery 33 instead of being built in the battery 33 as long as the molten salt battery 40 can be heated.

  Further, in order to allow the battery 33 to supply power to other devices (not shown) mounted on the vehicle 1, the battery 33 is connected to the other devices and the power conversion device 11 or the DC / DC converter. Electrical connection (not shown) is provided.

  As shown in FIG. 2, one molten salt battery 40 constituting the battery 33 accommodates a positive electrode 43, a negative electrode 44, and a separate 45 interposed between the positive electrode 43 and the negative electrode 44 inside a battery container 42. It consists of a structure that

The positive electrode 43 includes a positive electrode current collector 43a and a positive electrode active material layer 43b disposed inside the positive electrode current collector 43a (that is, between the positive electrode current collector 43a and the separate 45). The positive electrode current collector 43a is made of, for example, a porous body of an aluminum alloy, and the positive electrode active material layer 43b contains, for example, sodium chromite (NaCrO ₂ ) as the positive electrode active material.

  The negative electrode 44 includes a negative electrode current collector 44a and a negative electrode active material layer 44b disposed inside the negative electrode current collector 44a (that is, between the negative electrode current collector 44a and the separate 45). The negative electrode current collector 44a is made of, for example, aluminum foil, and the negative electrode active material layer 44b contains, for example, tin (Sn) as the negative electrode active material.

  The separate 45 is composed of a porous film of a fluororesin having resistance to molten salt at a temperature at which the molten salt battery 40 operates. Further, the separate 45 is immersed in a molten salt (not shown) filled in the battery container 42.

  In such a molten salt battery 40, the operating temperature range is, for example, 20 degrees to 90 degrees, a relatively high energy density is realized, and excellent safety can be ensured. Then, by heating the molten salt battery 40 to the operating temperature range, the molten salt is melted and can be charged and discharged.

  The vehicle 1 configured as described above travels by transmitting the driving force generated by the engine 2 or the motor 3 by the transmission 5 and then transmitting it to the driving wheels 9. For example, when the vehicle 1 decelerates or travels on a downhill road, the motor 3 operates as a generator by reverse driving from the drive wheel 9 side. The negative driving force generated by the motor 3 is transmitted to the driving wheel 9 side as a braking force, and the AC power generated by the motor 3 is converted into DC power by the power converter 31 and charged to the battery 33. .

  Further, in the vehicle 1 configured as described above, since the waste heat recovery circuit 12 is provided, the waste heat of the engine 2 is used to generate power by the generator 35, and the battery 33 stores electricity or other equipment. Can be powered. Here, in the waste heat recovery circuit 12 of the present embodiment, the high-temperature working fluid after being expanded by the expander 14 can be supplied to the condenser 16 via the second heat exchanger 15. The second heat exchanger 15 can exchange heat with the high-temperature working fluid, and the molten salt battery 40 adjacent to the second heat exchanger 15 can be heated (warmed up). In this way, by performing heat exchange for cooling the working fluid by the second heat exchanger 15, the temperature difference between the working fluid in the expander 14 and the condenser 16 can be further increased, and the waste heat recovery circuit 12 is recovered. As a result, the condensation efficiency can be improved.

  Furthermore, in the vehicle 1 configured as described above, the first heat exchanger 13, the flow rate adjusting valve 20, the expander 14, the bypass valve 21, the auxiliary circulation channel 19, the condenser 16, and the pump 17 are operated in this order. Since the waste heat recovery circuit 12 of this embodiment can be realized by adding the second heat exchanger 15 and the bypass valve 22 while applying the existing waste heat recovery circuit that circulates the fluid, the molten salt battery 40 is heated. Therefore, it is not necessary to provide the vehicle 1 with a dedicated additional facility. In other words, according to the configuration of the present embodiment, since the molten salt battery 40 can be heated by the second heat exchanger 15, it is not necessary to provide a new dedicated heat source for the molten salt battery 40. The cost of the vehicle 1 itself can be reduced. That is, in this embodiment, in order to improve the condensation efficiency of the waste heat recovery circuit 12, the heat radiated from the second heat exchanger 15 is effectively used to efficiently warm up the molten salt battery 40. Can do.

  When the battery 33 (that is, the molten salt battery 40) is in a low temperature state, such as when the vehicle 1 travels in a cold region or immediately after the vehicle 1 is started, the vehicle 1 performs warm-up for efficient warm-up control of the molten salt battery 40. A machine control unit 50 is provided. The warm-up control unit 50 includes one or a plurality of ECUs (electronic control units) mounted on the vehicle 1, and includes a motor 3, a pump 17, a flow rate adjustment valve 20, bypass valves 21 and 22, and a power conversion device 31. Control is possible.

  And the temperature sensor 41 provided in the molten salt battery 40 is connected to the warm-up control part 50, and the temperature signal of the molten salt battery 40 (namely, battery 33) is supplied.

  With such a configuration, the warm-up control unit 50 can control the open / close states of the flow rate adjustment valve 20 and the bypass valves 21 and 22 according to the temperature of the molten salt battery 40, and the second heat exchanger 15. The flow rate of the working fluid supplied to can be adjusted. That is, the warm-up control unit 50 uses the second heat exchanger 15 to bring the molten salt battery 40 within the operating temperature range when the temperature of the molten salt battery 40 is equal to or lower than the lower limit value (20 degrees) of the operating temperature range. It can be warmed up to fit in. Further, when the temperature of the molten salt battery 40 exceeds the upper limit value (90 degrees) of the operating temperature range, the warm-up control unit 50 stops supplying the working fluid to the second heat exchanger 15 and melts it. The warm-up of the salt battery 40 can be stopped.

  A warm-up control unit is configured by the warm-up control unit 50 and the bypass valves 21 and 22 from such a warm-up mechanism of the molten salt battery 40. And in this embodiment, the 1st heat exchanger 13, the expander 14, the 2nd heat exchanger 15, the condenser 16, the pump 17, the main circulation flow path 18, the auxiliary circulation flow path 19, the bypass valve 21, 22, the molten salt battery 40, the temperature sensor 41, and the warm-up control unit 50 constitute a vehicle molten salt battery warm-up device 60.

  Hereinafter, the warm-up control of the molten salt battery 40 performed by the warm-up control unit 50 will be described in detail.

  First, when the temperature of the molten salt battery 40 is higher than the lower limit value of the operating temperature range (that is, 20 degrees), the warm-up control unit 50 does not supply the working fluid to the second heat exchanger 15 and expands. The working fluid is circulated directly from the condenser 14 to the condenser 16. Specifically, the warm-up control unit 50 determines whether or not the temperature of the molten salt battery 40 is within the operating temperature range based on the temperature signal supplied from the temperature sensor 41. Thereafter, the warm-up control unit 50 determines that the temperature of the molten salt battery 40 is within the above operating temperature range and does not require the warm-up of the molten salt battery 40, and bypasses the working fluid so that the working fluid does not circulate to the battery 33. The open / close state of the valves 21 and 22 is controlled. When the control of the open / close state of the bypass valves 21 and 22 is completed, the warm-up control unit 50 drives the pump 17, and the first heat exchanger 13, the flow rate adjustment valve 20, the expander 14, the bypass valve 21, the condenser 16, The working fluid is circulated through the flow path in the order of the pumps 17.

  By such a circulation of the working fluid, it is possible to generate power by the generator 35 using the waste heat of the engine 2 and to perform good waste heat recovery.

  Next, when the temperature of the molten salt battery 40 is lower than the lower limit value of the operating temperature range, the warm-up control unit 50 controls the open / close state of the bypass valves 21 and 22 so as to warm up the molten salt battery 40. To do.

  Specifically, the warm-up control unit 50 controls the open / close state of the bypass valves 21 and 22 so that the working fluid flows through the battery 33 without flowing the working fluid through the auxiliary circulation channel 19. Depending on the open / closed state of the bypass valves 21 and 22, the first heat exchanger 13, the flow rate adjustment valve 20, the expander 14, the bypass valve 21, the second heat exchanger 15, the condenser 16, and the pump 17 are arranged in this order. A flow path is formed.

  When the working fluid is circulated through such a flow path, the working fluid that has driven the generator 35 by the expander 14 passes through the second heat exchanger 15. In a known Rankine cycle for vehicles generally used, the temperature of the working fluid downstream of the expander 14 is sufficiently higher than the lower limit of the operating temperature of the molten salt battery 40 (for example, 70 ° C. or higher). The molten salt battery 40 can be satisfactorily warmed up so that the temperature of the molten salt battery 40 falls within the operating temperature range by heat exchange in the second heat exchanger 15. Further, the exchange efficiency of the second heat exchanger 15 and the efficiency of the waste heat recovery circuit may be appropriately adjusted so that the molten salt battery 40 is warmed up to a desired temperature range.

  In addition, the cooling effect of the working fluid by the second heat exchanger 15 can increase the temperature difference between the working fluid in the expander 14 and the condenser 16, thereby improving the condensation efficiency of the waste heat recovery circuit 12. Can do. That is, the molten salt battery 40 can be warmed up by the second heat exchanger 15 while efficiently generating power by the generator 35 using the waste heat of the engine 2.

  After that, when the warm-up control unit 50 determines that the warm-up of the molten salt battery 40 has been completed based on the temperature signal supplied from the temperature sensor 41 (that is, warmed up to a desired temperature such as 20 degrees or higher), The machine control unit 50 controls the open / closed state of the bypass valves 21, 22, stops the supply of the working fluid to the battery 33, and circulates the working fluid via the auxiliary circulation channel 19.

  Then, after the molten salt battery 40 is warmed up, when the temperature of the molten salt battery 40 becomes less than 20 degrees again, the molten salt battery 40 is similarly warmed up by the above control. By controlling in this way, the temperature of the molten salt battery 40 can be maintained within the operating temperature range.

  In addition, after the warming-up of the molten salt battery 40 is completed, in order to maintain the temperature of the molten salt battery 40 above the lower limit temperature of the operating temperature range such as 20 degrees or more, the working fluid to the second heat exchanger 15 The supply amount of the working fluid may be adjusted within a range where the temperature of the molten salt battery 40 does not exceed the upper limit (that is, 90 degrees) of the operating temperature range without decreasing the supply. Also by such control, the temperature of the molten salt battery 40 can be maintained within the operating temperature range.

  Although the description about the embodiment of the warming-up device for a vehicle battery according to the present invention is finished above, the embodiment of the present invention is not limited to the above-described embodiment.

  In the above embodiment, the warm-up device is configured in the hybrid vehicle 1 in which the motor 3 is disposed between the clutch 4 and the transmission 5. However, the arrangement of the motor 3 is changed (for example, between the engine 2 and the clutch 4 or the speed change). It may be behind the machine 5). Further, different hybrid system configurations such as a configuration in which a plurality of motors 3 are mounted in the system, a so-called series hybrid system, or a series / parallel hybrid system may be used. Alternatively, the warm-up device may be configured in a vehicle in which only the engine (for example, a gasoline engine or a diesel engine) is used as a drive source by causing the motor 3 to function only as a generator.

  In the above embodiment, the first heat exchanger 13 directly exchanges heat with the exhaust gas of the engine 2. However, the exhaust gas of the engine 2 and the engine cooling water of the engine 2 are separated by another heat exchanger. The first heat exchanger 13 may be configured to perform heat exchange with the engine cooling water heated by the exhaust gas and then the first heat exchanger 13 (that is, heat exchange with the engine cooling water interposed). Furthermore, the battery 33 (that is, the second heat exchanger 15, the molten salt battery 40, and the temperature) of the present embodiment is added to the existing waste heat recovery circuit that does not use the exhaust gas of the engine 2 and uses the cooling water of the engine 2 as a heat source. The warming-up device 60 may be configured by combining the sensor 41).

1 Hybrid vehicle (vehicle)
2 Engine 3 Motor (electric motor)
DESCRIPTION OF SYMBOLS 11 Exhaust pipe 12 Waste heat recovery circuit 13 1st heat exchanger 14 Expander 15 2nd heat exchanger 16 Condenser 17 Pump 18 Main circulation flow path 19 Subcirculation flow path 20 Flow control valve 21 Bypass valve 22 Bypass valve 40 Melting Salt battery 41 Temperature sensor (temperature detector)
50 Warm-up control unit 60 Warm-up device

Claims (4)

A warm-up device for a molten salt battery for a vehicle mounted on a vehicle having an engine as a drive source,
A main circulation channel through which the working fluid circulates;
A first heat exchanger for heating the working fluid by a waste heat medium of the vehicle engine;
An expander that expands the working fluid heated by the first heat exchanger to generate a rotational driving force;
A second heat exchanger that exchanges heat with the working fluid discharged from the expander;
A condenser for cooling the working fluid discharged from the second heat exchanger;
A pump for sending the working fluid cooled by the condenser to the first heat exchanger;
A warming-up device for a molten salt battery for a vehicle, comprising: a molten salt battery that exchanges heat with the second heat exchanger and is warmed up to an operating temperature range. A temperature detection unit for detecting a temperature for detecting the temperature of the molten salt battery;
A secondary circulation flow path for directly circulating the working fluid from the expander to the condenser;
The vehicle molten salt battery according to claim 1, further comprising: a warm-up control unit that circulates the working fluid through the auxiliary circulation channel when the temperature of the molten salt battery is within an operating temperature range. Warm-up device.   When the temperature of the molten salt battery is within an operating temperature range, the warm-up control means circulates the working fluid only through the sub-circulation flow path without passing through the second heat exchanger. The warming-up device of the molten salt battery for vehicles according to claim 2 to be made.   The warm-up control means includes a flow rate adjustment valve on the main circulation channel, between the expander and the second heat exchanger, and between the second heat exchanger and the condenser. The warming-up device for the molten salt battery for a vehicle according to claim 2 or 3.

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