JP2014063713A - Energy management system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow for effective reuse of refrigerant used for cooling a secondary battery.SOLUTION: An energy management system includes a fuel cell for supplying power to a load, and a secondary battery for storing surplus power at least of the fuel cell and supplying the power thus stored to a load. Furthermore, the energy management system includes a heat recovery apparatus in which a refrigerant pipe is arranged to recover the heat generated in the fuel cell and the heat generated in the secondary battery. More specifically, in a co-generation system for recovering and reusing heat generated by power generation of fuel cell, the heat generated by charge/discharge of the secondary battery is also recovered. Consequently, the heat generated by the secondary battery is cooled by heat recovery, and the refrigerant is utilized in the co-generation system as the refrigerant.

Description

  The present invention relates to an energy management system.

Secondary batteries such as lithium ion batteries generate heat during charging and discharging. Such heat generation promotes the deterioration of the secondary battery itself, thereby leading to a reduction in the life of the secondary battery, a reduction in capacity, and a reduction in output.
Thus, a technique is known in which a cooling jacket is attached around the secondary battery in order to cool the secondary battery (see, for example, Patent Document 1). The cooling jacket includes a water tank and a pump, and operates the pump to supply water to cool the secondary battery by a water cooling method.

JP 2000-173664 A

  When the secondary battery is cooled with a coolant such as water as described above, if the coolant used for cooling is reused, resources are effectively used, which is preferable in terms of economy. However, in patent document 1, there is no description regarding the reuse of the water (refrigerant) supplied to the cooling jacket for cooling the secondary battery.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to effectively reuse the refrigerant used for cooling the secondary battery.

  In order to solve the above-described problems, an energy management system as one aspect of the present invention includes a fuel cell that supplies power to a load, stores at least surplus power of the fuel cell, and supplies the stored power to the load. And a heat recovery device arranged to recover heat generated in the fuel cell and heat generated in the secondary battery with respect to the refrigerant pipe through which the refrigerant flows.

  Further, in the energy management system of the present invention, the secondary battery piping section that recovers the heat generated in the secondary battery in the refrigerant pipe is disposed so as to recover the heat generated in the fuel cell. You may arrange | position so that it may become upstream with respect to a part.

  Further, in the energy management system of the present invention, the refrigerant pipe is arranged in parallel with the secondary battery piping part for recovering the heat generated in the secondary battery so as not to recover the heat generated in the secondary battery. A secondary battery bypass piping section, a temperature state determination section for determining a temperature state of the secondary battery, and a refrigerant in the refrigerant pipe based on the temperature state determined by the temperature state determination section. You may further provide the path | route control part which switches between the path | route which flows through a piping part, and the path | route which a refrigerant | coolant flows through the said secondary battery bypass piping part.

  As described above, according to the present invention, it is possible to effectively reuse the refrigerant used for cooling the secondary battery.

It is a figure which shows the structural example about the electric power grid | system in the energy management system which concerns on 1st Embodiment. It is a figure which shows the structural example about the cogeneration system system | strain in the energy management system which concerns on 1st Embodiment. It is a figure which shows typically the structural example of the secondary battery piping part which concerns on 2nd Embodiment. It is a figure which shows the structural example about the cogeneration system system | strain in the energy management system which concerns on 2nd Embodiment. It is a flowchart which shows the example of a process sequence which the electric power control part which concerns on 2nd Embodiment performs.

[First Embodiment]
FIG. 1 shows a configuration example of a power system in an energy management system 1 according to the present embodiment. The energy management system 1 of this embodiment manages the energy used in facilities, such as a house, for example.

  The energy management system 1 according to the present embodiment shown in FIG. 1 includes a fuel cell 10, a secondary battery 20, an inverter 30, a distribution board 40, a power control unit 50, a load 60, and a hot water storage unit 70.

The fuel cell 10 supplies power to the load 60. The fuel cell 10 is a power generator that continuously discharges by reacting a replenishable negative electrode active material (for example, hydrogen) and a positive electrode active material (oxygen in the air, etc.). Further, the fuel cell 10 can be permanently discharged by continuously replenishing the negative electrode active material and the positive electrode active material.
The power output from the fuel cell 10 is direct current. Therefore, the inverter 30 converts the DC power output from the fuel cell 10 into AC and supplies it to the load 60 via the distribution board 40.

  The secondary battery 20 is supplied with surplus power that is not consumed by the load 60 among the power supplied by the fuel cell 10. The secondary battery 20 stores this surplus power. The secondary battery 20 supplies the accumulated power to the load 60. The power output from the secondary battery 20 is direct current. For this reason, when supplying the electric power accumulated in the secondary battery 20 to the load 60, the inverter 30 converts the DC power output from the secondary battery 20 into an alternating current, and the load 60 via the distribution board 40. To supply.

Note that the power of the commercial power source 2 may be stored in the secondary battery 20. For this purpose, for example, the inverter 30 is configured as a bidirectional inverter, and then, as shown by the broken arrow in FIG. 1, the alternating current of the commercial power supply 2 is converted into direct current by the inverter 30 to charge the secondary battery 20. Can be supplied as Alternatively, in addition to the inverter 30, a converter that converts the alternating current of the commercial power source 2 into direct current by the inverter 30 may be provided.
In this way, by allowing the secondary battery 20 to also store the power of the commercial power supply 2, for example, it is possible to charge the secondary battery 20 with midnight power with an inexpensive electricity bill.

As described above, the inverter 30 converts the DC power output from the fuel cell 10 or the secondary battery 20 into AC and supplies it to the load 60 via the distribution board 40.
If the inverter 30 is configured as a bidirectional inverter, as described above, the secondary battery 20 can be charged with the power of the commercial power source 2 without adding a converter.

The distribution board 40 is configured to supply power to the load 60 that is output from the inverter 30 (power obtained by converting the discharge power of the fuel cell 10 or the secondary battery 20 into alternating current) under the control of the power control unit 50. Then, switching is performed between a path for supplying power from the commercial power source 2 to the load 60.
Further, when the inverter 30 is a bidirectional inverter, the distribution board 40 also switches to a path for charging the secondary battery 20 with the power of the commercial power source 2 in accordance with the control of the power control unit 50.

  The power control unit 50 executes control for energy management in the energy management system. The power control unit 50 corresponds to, for example, a home energy management system called HEMS (Home Energy Management System). For this purpose, the power control unit 50 controls, for example, the power generation operation of the fuel cell 10, the charge / discharge operation of the secondary battery 20, the power conversion operation of the inverter 30, the power path switching in the distribution board 40, and the like. The power control unit 50 can also control water supply to the hot water storage unit 70, hot water supply from the hot water storage unit 70, and the like.

  The load 60 is a home electric appliance or the like in the house 3, and is a device or a circuit that consumes power for its own operation.

  The hot water storage unit 70 increases the temperature of the cold water supplied from the water supply pipe 71 to convert it into hot water (hot water), and stores this hot water. The hot water stored in the hot water storage unit 70 is supplied to the house 3 via the hot water supply pipe 72. In the house 3, the hot water supplied from the hot water storage unit 70 is used as hot water in, for example, a bath, a kitchen and a washroom, or used for floor heating or the like.

Moreover, in the energy management system 1 of this embodiment, the cold water supplied to the hot water storage unit 70 is converted into hot water by raising the temperature of the cold water using heat generated when the fuel cell 10 generates power. That is, the energy management system of the present embodiment has a configuration as a cogeneration system that recovers heat generated by the power generation of the fuel cell 10 and converts cold water into hot water by the recovered heat.
In addition, the cogeneration system in the energy management system 1 of the present embodiment is configured by further incorporating the secondary battery 20. That is, the cogeneration system of the present embodiment has a configuration in which cold water is converted into hot water by collecting heat generated during charging / discharging of the secondary battery 20 in addition to heat generated by power generation of the fuel cell 10.

  FIG. 2 shows a configuration example of the cogeneration system system in the energy management system 1 of the first embodiment. In FIG. 2, the same parts as those in FIG. In FIG. 2, the illustration of the inverter 30, the distribution board 40, the power control unit 50, and the load 60 shown in FIG. 1 is omitted for convenience of illustration.

As shown in FIG. 2, in the cogeneration system system of the present embodiment, a refrigerant pipe 80 is provided for the fuel cell 10, the secondary battery 20, and the hot water storage unit 70.
The refrigerant pipe 80 functions as a heat recovery apparatus in the present embodiment, and is a pipe through which water as a refrigerant flows. The cold water supplied from the water supply pipe 71 to the hot water storage unit 70 is supplied to the refrigerant pipe 80.

The refrigerant pipe 80 has a fuel cell piping part 81 and a secondary battery piping part 82 in its piping.
The fuel cell piping section 81 is arranged so as to recover the heat generated in the fuel cell 10. The structure of the piping as the fuel cell piping section 81 is not particularly limited, but it is preferable that the piping is connected to the fuel cell 10 so that heat can be efficiently recovered from the fuel cell 10.
Moreover, the secondary battery piping part 82 is arrange | positioned so that the heat | fever which generate | occur | produces in the secondary battery 20 may be collect | recovered. The structure of the piping of the secondary battery piping section 82 is not particularly limited, but it is preferable that the piping is connected to the secondary battery 20 so that heat can be efficiently recovered from the secondary battery 20.

The cold water supplied to the refrigerant pipe 80 first passes through the secondary battery piping section 82. Thereby, heat is recovered from the secondary battery 20, and the cold water is warmed by the recovered heat, and the temperature rises. Next, the water that has passed through the secondary battery piping part 82 passes through the fuel cell piping part 81, so that the temperature further rises to become hot water. The hot water thus produced passes through the downstream refrigerant pipe 80 from the fuel cell piping section 81 and is supplied again to the hot water storage unit 70. The hot water storage unit 70 stores the hot water supplied in this way and supplies it to the house 3 from the hot water supply pipe 72 as necessary.
With such a configuration, in the energy management system of the present embodiment, the heat generated in the fuel cell 10 and the secondary battery 20 can be reused to create hot water.

Here, when the calorific values of the fuel cell 10 and the secondary battery 20 are compared, since the fuel cell 10 is larger, the contribution rate of the fuel cell 10 than that of the secondary battery 20 is greater in producing hot water. high.
However, the secondary battery 20 has a property that deterioration is accelerated by heat generated during charging and discharging. Therefore, if the heat recovery is also performed from the secondary battery 20 in the cogeneration system system as in this embodiment, the secondary battery 20 is cooled by the heat recovery. It is possible to effectively suppress deterioration of the material.

  Moreover, although the calorific value is smaller than that of the fuel cell 10, hot water can be efficiently produced by using the heat recovered from the secondary battery 20. For example, since the power required by the load 60 is small, the power output from the fuel cell 10 is also small, and the heat recovered from the secondary battery 20 is also used even when the amount of heat generated by the fuel cell 10 is small. By doing so, it becomes easy to produce hot water of a necessary temperature.

  As described above, in the present embodiment, when viewed from the viewpoint of cooling the secondary battery 20, the refrigerant for cooling the secondary battery 20 is effectively reused as the refrigerant in the cogeneration system.

In addition, in the present embodiment, in the refrigerant pipe 80, the secondary battery piping portion 82 is disposed upstream of the fuel cell piping portion 81. As a result, low-temperature cold water before being heated by the heat recovered from the fuel cell 10 flows through the secondary battery piping unit 82, so that the secondary battery piping unit 82 is located downstream of the fuel cell piping unit 81. Compared with the case where it arrange | positions to, the cooling effect of the secondary battery 20 can be heightened.
Further, since the secondary battery piping unit 82 is disposed upstream of the fuel cell piping unit 81, the water supplied to the fuel cell piping unit 81 is already in the secondary battery piping unit 82. It has already been warmed to some extent by the heat recovered from it. Thereby, in the fuel cell piping part 81, since it can begin to warm a refrigerant | coolant from an already warm state, it is possible to raise the temperature of a refrigerant | coolant efficiently.

<Second Embodiment>
For example, the secondary battery piping section 82 is arranged so that the contact area with the secondary battery 20 is as large as possible so that the secondary battery 20 can be efficiently cooled. As an example, as schematically shown in FIG. 3, the secondary battery piping section 82 is arranged with respect to the secondary battery 20 by a piping shape bent in a meander line shape, for example.
The secondary battery piping part 82 has a considerable length due to the shape as described above, for example. As described above, the piping of the secondary battery piping section 82 becomes longer, so that the pressure for flowing the refrigerant through the refrigerant pipe 80 is reduced. In a state where the pressure in the refrigerant pipe 80 is reduced, for example, the amount of hot water discharged from the refrigerant pipe 80 to the hot water storage unit is reduced, and there is a problem that the amount of hot water required in the house 3 cannot be secured immediately. there is a possibility.
For example, if a pump for flowing the refrigerant is provided in the refrigerant pipe 80, pressure can be applied by the pump, so that the problem that the necessary amount of hot water cannot be secured as described above can be avoided. In this case, however, extra power is required to drive the pump in order to compensate for the pressure drop due to the long piping.
Further, the secondary battery 20 generates less heat than, for example, the fuel cell 10. For example, depending on the operation at that time, cooling is not particularly necessary, and the secondary battery 20 can contribute to an increase in the temperature of the refrigerant. In some cases, the temperature does not rise.

Therefore, in the cogeneration system system of the second embodiment, switching between a state in which the secondary battery 20 is cooled and a state in which the secondary battery 20 is not cooled is performed according to the temperature state of the secondary battery 20 as described below. Like that.
FIG. 4 shows a configuration example of the cogeneration system system in the energy management system 1 of the second embodiment. In FIG. 4, the same parts as those in FIG.

In the cogeneration system system shown in FIG. 4, a secondary battery bypass piping part 83 is arranged in parallel to the secondary battery piping part 82.
The secondary battery bypass piping part 83 is arranged so as not to recover the heat generated in the secondary battery 20. Further, the secondary battery bypass pipe portion 83 does not have a meander-line bent shape like the secondary battery pipe portion 82 in FIG. 3, for example, other than a portion that needs to be bent for piping. Is a stretched shape.

Both ends of the secondary battery piping section 82 and the secondary battery bypass piping section 83 are connected to the path switchers 91 and 92.
The path switchers 91 and 92 include a path through which the refrigerant flows through the secondary battery piping section 82 and a path through which the refrigerant flows through the secondary battery bypass piping section 83 according to the control of the path control section 52 in the power control section 50. Switch.

Corresponding to the second embodiment, the power control unit 50 includes, for example, a temperature state determination unit 51 and a path control unit 52 as illustrated.
The temperature state determination unit 51 determines the temperature state of the secondary battery 20. Specifically, the temperature state determination unit 51 determines whether or not the temperature of the secondary battery 20 may become a certain level or higher (hereinafter also referred to as a high temperature state) based on the operation of the secondary battery 20. Judge about.

  The path control unit 52 includes a path through which the refrigerant flows through the secondary battery piping unit 82 and a path through which the refrigerant flows through the secondary battery bypass piping unit 83 in the refrigerant pipe 80 based on the temperature state determined by the temperature state determination unit 51. Switch between.

  Specifically, when the temperature state determination unit 51 determines that the temperature state of the secondary battery 20 is a high temperature state, the path control unit 52 switches the path so that the refrigerant flows through the secondary battery piping unit 82. The devices 91 and 92 are controlled. Thereby, in the refrigerant pipe 80, the refrigerant flows into the secondary battery piping portion 82, whereby the secondary battery 20 in a high temperature state can be cooled and heat can be recovered from the secondary battery 20.

On the other hand, when the temperature state determination unit 51 determines that the temperature state of the secondary battery 20 is not a high temperature state, that is, the temperature of the secondary battery 20 is less than a certain level, the path control unit 52 The path switches 91 and 92 are controlled so that the refrigerant flows through the bypass pipe portion 83.
In this case, since the refrigerant does not flow through the secondary battery piping section 82, the secondary battery 20 cannot be cooled to recover heat. However, since the temperature of the secondary battery 20 at this time is less than a certain value, there is no particular need for cooling, and the contribution to the rise in the temperature of the refrigerant due to heat recovery is considerably small. That is, when the secondary battery 20 is at a low temperature, it is not necessary to cool the secondary battery 20 and perform heat recovery. Therefore, even if the refrigerant does not flow into the secondary battery piping section 82, no particular problem occurs.
In addition, since the secondary battery bypass piping portion 83 is not in a shape having a large number of bent portions, for example, like the secondary battery piping portion 82, the length thereof is equivalent to that of the secondary battery piping portion 82, for example. Short. For this reason, by flowing the refrigerant through the secondary battery bypass pipe portion 83, for example, the pressure for flowing the refrigerant becomes higher than when the refrigerant is flowing through the secondary battery pipe portion 82.

As described above, in the second embodiment, when the temperature of the secondary battery 20 is high, the coolant is caused to flow through the secondary battery piping portion 82 to cool the secondary battery 20 and recover heat from the secondary battery 20. On the other hand, when the temperature of the secondary battery 20 is low, the refrigerant is allowed to flow through the secondary battery bypass pipe 83 having a short pipe length without flowing the refrigerant through the secondary battery pipe 82, thereby increasing the pressure for flowing the refrigerant. To do.
As a result, in the second embodiment, when the secondary battery 20 is at a low temperature and does not require cooling and heat recovery, it is possible to maintain a high pressure for flowing the refrigerant. It is possible to reduce the possibility of inconveniences that cannot be ensured.
Further, when a pump is used to flow the refrigerant through the refrigerant pipe 80, when the refrigerant is flowing through the secondary battery bypass pipe 83, the pressure loss due to the length of the pipe is reduced. The driving force of the pump can be set low, and the power consumption can be reduced.

  The flowchart in FIG. 5 illustrates an example of a processing procedure executed by the temperature state determination unit 51 and the path control unit 52 of the power control unit 50 according to the second embodiment. In the flowchart of FIG. 5, a specific example of the operation state of the secondary battery 20 used when the temperature state determination unit 51 determines the temperature state is shown. Further, the process shown in FIG. 5 is executed, for example, at regular intervals.

  The temperature state determination unit 51 inputs the operation mode, voltage value, and current value information from the secondary battery 20 (step S101). The operation mode is information indicating, for example, whether the current operation of the secondary battery 20 is charging, discharging, or stopped.

Next, the temperature state determination unit 51 determines whether or not the secondary battery 20 is being charged based on the operation mode input in step S101 (step S102). The secondary battery 20 has a property that the temperature rises in a charged state.
Therefore, when the secondary battery 20 is being charged (step S102—YES), the temperature state determination unit 51 determines that it is in a high temperature state. In response to this determination, the path control unit 52 executes control for path switching so that the refrigerant flows through the secondary battery piping unit 82 (step S107).

When the secondary battery 20 is not being charged (step S102—NO), the temperature state determination unit 51 further determines that the voltage value is equal to or less than a predetermined value based on the operation mode and voltage value input in step S101. It is determined whether or not the battery 20 is being discharged (step S103). In a state where the voltage value is below a certain level and the secondary battery 20 is being discharged, the secondary battery 20 is likely to be in a high temperature state. Such a state is likely to occur at the end of discharge in which discharge is performed in a state where the electric power stored in the secondary battery 20 is reduced below a certain level.
Therefore, when the voltage value is equal to or lower than the predetermined value and the secondary battery 20 is in a discharging state (step S103—YES), the temperature state determination unit 51 determines that the temperature state is high. In response to this determination, the path control unit 52 executes control for path switching so that the refrigerant flows through the secondary battery piping unit 82 (step S107).

When the voltage value is not more than a certain value and the secondary battery 20 is not in a discharging state (step S103-NO), the temperature state determination unit 51 further, based on the operation mode and current value input in step S101, It is determined whether or not the current value is equal to or greater than a certain value and the secondary battery 20 is in a discharging state (step S104). In a state where the amount of current is large when the secondary battery 20 is discharged, there is a high possibility that the secondary battery 20 will be at a high temperature.
Therefore, when the current value is equal to or greater than a certain value and the secondary battery 20 is in a discharging state (step S104—YES), the temperature state determination unit 51 determines that the temperature is high. In response to this determination, the path control unit 52 executes control for path switching so that the refrigerant flows through the secondary battery piping unit 82 (step S107).

When the current value is equal to or greater than a certain value and the secondary battery 20 is not in a discharging state (step S104—NO), the temperature state determination unit 51 further, based on the operation mode and voltage value input in step S101, It is determined whether or not the voltage value is greater than or equal to a certain value when the secondary battery 20 is stopped (step S105). There is a high possibility that the secondary battery 20 will be in a high temperature state when the voltage value is above a certain level even during the stop.
Therefore, when the voltage value is equal to or higher than a certain value while the secondary battery 20 is stopped (step S105—YES), the temperature state determination unit 51 determines that the temperature is high. In response to this determination, the path control unit 52 executes control for path switching so that the refrigerant flows through the secondary battery piping unit 82 (step S107).

On the other hand, when the voltage value is less than a certain value while the secondary battery 20 is stopped (step S105—NO), the secondary battery 20 is in a low temperature state. Therefore, the temperature state determination unit 51 in this case determines that the temperature is not high. In response to this determination, the path control unit 52 performs control for path switching so that the refrigerant flows through the secondary battery bypass pipe unit 83 (step S106).
In addition, the temperature state determination part 51 may provide a temperature sensor etc. in the secondary battery 20, for example, and may determine a temperature state based on the temperature which a temperature sensor shows. In this case, the temperature state determination unit 51 may omit the determinations of steps S102 to S106 in FIG. 5, and may determine the temperature indicated by the temperature sensor and the determination of at least one of steps S102 to S106. In combination, the temperature state may be finally determined.

Moreover, although the cogeneration system in the description so far uses the water supplied to the hot water storage unit 70 as a refrigerant, the refrigerant is not limited to this. For example, the refrigerant may be a liquid mainly composed of ethylene glycol. Such a liquid is used, for example, as an antifreeze liquid. By warming the antifreeze liquid with a cogeneration system, the performance of the antifreeze liquid can be sufficiently and stably exhibited. Moreover, a chemical heat pipe can also be applied as the heat recovery apparatus of this embodiment. The chemical heat pipe converts heat energy into chemical energy by a decomposition reaction using recovered heat. Also, other than the hot water storage unit 70, a heat reuse device that reuses the heat recovered by the heat recovery device according to the type of the refrigerant or the like may be applied.
Moreover, although the structural example of the energy management system shown in FIG.1 and FIG.2 respond | corresponds to HEMS, it is applicable also to the energy management system corresponding to BEMS (Building and Energy Management System) etc., for example.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Energy management system 2 Commercial power supply 3 House 10 Fuel cell 20 Secondary battery 30 Inverter 40 Distribution board 50 Power control part 60 Load 70 Hot water storage unit 71 Water supply pipe 72 Hot water supply pipe 80 Refrigerant pipe 81 Fuel cell piping part 82 Secondary battery piping 83 Secondary battery bypass piping

Claims (3)

A fuel cell for supplying power to the load;
A secondary battery that accumulates at least surplus power of the fuel cell and supplies the accumulated power to the load;
An energy management system comprising: a heat recovery device arranged to recover heat generated in the fuel cell and heat generated in the secondary battery with respect to a refrigerant pipe through which the refrigerant flows. The secondary battery piping section that recovers the heat generated in the secondary battery in the refrigerant pipe is disposed upstream from the fuel cell piping section that is disposed so as to recover the heat generated in the fuel cell. The energy management system according to claim 1. A secondary battery bypass piping portion arranged so as not to recover the heat generated in the secondary battery in parallel with the secondary battery piping portion recovering the heat generated in the secondary battery in the refrigerant tube;
A temperature state determination unit for determining a temperature state of the secondary battery;
Based on the temperature state determined by the temperature state determination unit, the refrigerant pipe switches between a path through which the refrigerant flows through the secondary battery pipe section and a path through which the refrigerant flows through the secondary battery bypass pipe section. The energy management system according to claim 1, further comprising: a path control unit.

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