JP2008147121A - Fuel cell evaluation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control temperature of cooling liquid accurately at the time of adjusting of a cooling liquid volume of a cooling liquid circulating system in a fuel cell evaluation device managing temperature of a fuel cell by the cooling liquid circulating system and evaluating performance of the fuel cell. <P>SOLUTION: The fuel cell evaluation device 10 includes a cooling liquid circulating system 12 and a control part 60 for controlling the latter 12. The control part 60 reduces thermal dose by a heater 26 for fine tuning when the control part controls to reduce cooling liquid volume flowing in the fuel cell, and also, it controls to increase radiation heat volume of a heat radiation part 28 provided between the heater 26 for fine tuning and a fuel cell 14. With this, temperature of the cooling liquid sent to the fuel cell 14 does not increase, thus, the temperature of the cooling liquid can be accurately controlled. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell evaluation apparatus that evaluates the performance of a fuel cell, and more particularly to a coolant circulation system that manages the temperature of the fuel cell.

  2. Description of the Related Art A fuel cell is a cell that generates electricity by electrochemically reacting a fuel gas and an oxidizing gas, and a fuel cell evaluation device that evaluates the performance of the fuel cell by setting various environmental conditions is known. In this fuel cell evaluation apparatus, there is an example having a coolant circulation system for circulating a coolant through the fuel cell in order to manage the temperature of the fuel cell.

  The coolant circulation system usually includes a pump that circulates the coolant and a heat exchanger that cools the coolant. By the operation of the pump, the coolant cooled by the heat exchanger flows through the fuel cell, where the reaction heat is removed, and the temperature of the fuel cell is controlled. In order to set various environmental conditions, there is an example in which a heater that adjustably heats the coolant is provided between the heat exchanger and the fuel cell. The heater adds a necessary heating amount to the coolant based on the temperature of the fuel cell, for example, the temperature of the coolant flowing out of the fuel cell. Thereby, various environmental conditions, for example, environmental conditions such as operation of the fuel cell at high temperature can be set, and the performance of the fuel cell can be evaluated.

  Patent Document 1 listed below describes a fuel cell evaluation device that evaluates the performance of a fuel cell by setting the fuel cell to an actual operating temperature with temperature-controlled cooling water.

JP 2003-203667 A

  There is an example in which the flow rate of the coolant flowing through the fuel cell is adjusted so that various environmental conditions can be set in the coolant circulation system provided with the heater. In this coolant circulation system, when the flow rate of the coolant flowing through the fuel cell is decreased, control is performed to decrease the heating amount of the heater in accordance with the decrease in the flow rate. However, a delay time occurs until the heating amount of the heater decreases to the set value. As a result, there is a problem that during the delay time, an excessive amount of heating is applied to the coolant and the temperature of the coolant rises.

  An object of the present invention is to provide a fuel cell evaluation and test apparatus that can control the temperature of the coolant more accurately when adjusting the amount of coolant in the coolant circulation system that manages the temperature of the fuel cell. .

  The present invention is a fuel cell evaluation apparatus that manages the temperature of a fuel cell by a coolant circulation system and evaluates the performance of the fuel cell, and the coolant circulation system adjusts the flow rate of the coolant flowing through the fuel cell. A flow rate adjusting means; a heating means for heating the cooling liquid in an adjustable manner; and a heat radiating means provided between the heating means and the fuel cell for radiating the heat of the cooling liquid in an adjustable manner. When the flow rate of the cooling liquid is controlled to be reduced by the means, the controller has a control unit that reduces the amount of heating by the heating means and increases the heat radiation amount of the heat radiating means.

  The heat dissipating means includes a first flow path in which a coolant flows from the heating means to the fuel cell, a second flow path in which the coolant flows around at least a part of the first flow path, and the second flow path. An adjustment valve that adjusts the flow rate of the coolant flowing through the second flow path, and the heat release amount of the second flow path can be made larger than the heat release amount of the first flow path corresponding to the second flow path.

  The fuel cell evaluation apparatus of the present invention can control the temperature of the coolant more accurately when adjusting the amount of coolant in the coolant circulation system that manages the temperature of the fuel cell.

  Hereinafter, the fuel cell evaluation apparatus 10 of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a coolant circulation system 12 of a fuel cell evaluation device 10 according to the present embodiment.

  The fuel cell evaluation device 10 is a device that sets various environmental conditions and evaluates the performance of the fuel cell 14. In the present embodiment, as an example, a polymer electrolyte fuel cell having excellent in-vehicle properties is cited, and a fuel cell evaluation device 10 that evaluates the performance of the fuel cell evaluation device 10 will be described.

  The fuel cell evaluation apparatus 10 includes a coolant circulation system 12 that manages the temperature of the fuel cell 14, a gas supply system (not shown) that manages fuel gas and oxidant gas supplied to the fuel cell 14, and fuel generated by power generation. It has a discharge system (not shown) for managing the power discharged from the battery 14 and a control unit 60 for measuring and controlling these systems. The control unit 60 performs control based on the measured values of each system so as to satisfy the set environmental conditions, and the power generated by the fuel cell 14 by the discharge system is measured, and the performance of the fuel cell 14 is evaluated. .

  The fuel cell 14 is a device that generates electricity by causing an electrochemical reaction between a fuel gas and an oxidizing gas. Generally, a fuel cell has a plurality of cells in which a membrane-electrode assembly (MEA) composed of an electrolyte membrane sandwiched between a fuel electrode and an air electrode is further sandwiched between two separators. And a stack formed by stacking these. It should be noted that the present invention can also be applied to a state in which the fuel cell 14 to be evaluated is stacked or before the fuel cell 14 is stacked, for example, a state of a single MEA.

The electrochemical reaction in the fuel cell 14 will be described. Fuel gas (hydrogen gas) is supplied to the fuel electrode of the cell, and oxidizing gas (air) is supplied to the air electrode. At the fuel electrode, the fuel gas is dissociated into hydrogen ions and electrons, and the dissociated hydrogen ions permeate the electrolyte membrane and move to the air electrode. Further, the dissociated electrons move to the air electrode through the discharge system. On the other hand, at the air electrode, hydrogen ions that have permeated through the electrolyte membrane and electrons supplied through the discharge system react with oxygen contained in the air, and water is generated by this reaction.
Fuel electrode side: H ₂ → 2H ⁺ + 2e ⁻
Air electrode side: 2H ⁺ + 2e ⁻ + (1/2) O ₂ → H ₂ O

  This series of electrochemical reactions generates electricity in the cell. In the case where the fuel cell 14 is a stack composed of a plurality of cells, each cell is electrically connected directly. Therefore, the voltage obtained by adding the voltage of the power generated by each cell is the total voltage of the fuel cell 14. It becomes. Further, this series of electrochemical reactions generates heat in the cell. The heat generated in the cell is removed by the coolant in the coolant circulation system 12.

  The coolant circulation system 12 includes a heat exchanger 18 that cools the coolant, a tank 22 that stores the coolant, a pump 20 that circulates the coolant, a fine adjustment heater 26 that heats the coolant, and a coolant. A heat radiating portion 28 for radiating heat is provided. Further, these devices and the fuel cell 14 are connected in order, and a circulation channel 16 through which the coolant circulates is provided. By the operation of the pump 20, the coolant circulating through the circulation flow path 16 is adjusted to a set temperature by the heat exchanger 18, the fine adjustment heater 26 and the heat radiating unit 28. The coolant adjusted to the set temperature is sent to the fuel cell 14, where heat generated therein is removed, and the temperature of the fuel cell 14 is controlled.

  The circulation channel 16 is provided with a heat insulating member on the outer periphery of the tube, and has a heat insulation structure that blocks heat transfer between the coolant flowing through the circulation channel 16 and the outside of the circulation channel 16. The heat insulating member is made of a material having a low thermal conductivity, and is a heat insulating material such as hard urethane home or glass wool. With the heat insulating structure provided with such a heat insulating material, the heat loss of the coolant can be reduced, and the temperature of the coolant sent to the fuel cell 14 can be accurately managed.

  The cooling circulation system 12 has a bypass flow path 40 that bypasses the fuel cell 14. Both ends of the bypass flow path 40 are connected to the circulation flow path 16 between the pump 20 and the fine adjustment heater 26 and the circulation flow path 16 between the fuel cell 14 and the heat exchanger 18, respectively. A portion where one end of the bypass passage 40 is connected to the circulation passage 16 between the pump 20 and the fine adjustment heater 26 is a portion where the coolant flowing through the fuel cell 14 and the coolant bypassing the fuel cell 14 are separated. This is hereinafter referred to as a flow dividing portion 16a. On the other hand, the portion where the other end of the bypass flow path 40 is connected to the circulation flow path 16 between the fuel cell 14 and the heat exchanger 18 includes a coolant that flows through the fuel cell 14 and a coolant that bypasses the fuel cell 14. Is a portion that merges, and is hereinafter referred to as a merge portion 16b. The bypass channel 40 has the same heat insulating structure as the circulation channel 16.

  A bypass channel two-way valve 44 is disposed in the bypass channel 40. In addition, a circulation flow path two-way valve 42 is disposed in the flow path 16 between the branch portion 16 a and the fine adjustment heater 26. The bypass channel two-way valve 44 and the circulation channel two-way valve 42 adjust the flow rate of the coolant flowing through the fuel cell 14 by the controller 60 instructing and adjusting the opening degree thereof. When the flow rate of the coolant flowing through the fuel cell 14 is increased, the control unit 60 controls the control signal so that the opening degree of the circulation flow path two-way valve 42 increases and the opening degree of the bypass flow path two-way valve 44 decreases. Send. On the other hand, when the flow rate of the coolant flowing through the fuel cell 14 is decreased, the control unit 60 is configured so that the opening degree of the circulation flow path two-way valve 42 is decreased and the opening degree of the bypass flow path two-way valve 44 is increased. Send a control signal. The flow rate of the coolant flowing through the fuel cell 14 is detected by a flow rate sensor 46 disposed in the circulation channel 16 between the circulation channel two-way valve 42 and the fine adjustment heater 26, and a detection signal is sent to the control unit 60. Is output.

  The heat exchanger 18 flows through the fuel cell 14 and cools the coolant heated by the reaction heat by heat exchange with the liquid refrigerant. The heat exchanger 18 adjusts the cooling amount by adjusting the flow rate or temperature of the liquid refrigerant.

  The tank 22 is a container for storing a coolant, and the container is provided with a coarse adjustment heater 24 for heating the stored coolant.

  As described above, the coolant circulation system 12 is provided with two heaters, the coarse adjustment heater 24 and the fine adjustment heater 26. The heating amounts of the heaters 24 and 26 can be adjusted according to the set temperature according to the instruction from the control unit 60. The coarse adjustment heater 24 roughly adjusts the temperature of the coolant, whereas the fine adjustment heater 26 finely adjusts the temperature of the coolant. The coolant heated by the coarse adjustment heater 24 and roughly adjusted in temperature is sent to the fine adjustment heater 26 and finely adjusted so that the temperature of the coolant becomes the set temperature. Then, the coolant that has reached the set temperature is sent to the fuel cell 14, and the temperature of the fuel cell 14 is managed with high accuracy. The temperature of the fuel cell 14 is detected by a fuel cell outlet temperature sensor 48 disposed in the circulation flow path 16 between the fuel cell 14 and the merging portion 16 b, and a detection signal is output to the control unit 60.

  The heat radiating section 28 is provided between the fine adjustment heater 26 and the fuel cell 14. The heat radiating section 28 includes a heat radiating section main flow path 30 through which the coolant flows from the fine adjustment heater 26 to the fuel cell 14, and a heat radiating section bypass flow path 32 through which at least a part of the heat radiating section flows. Both ends of the heat radiating part bypass flow path 32 are connected to the heat radiating part main flow path 30. That is, one end of the three-way valve 34 disposed in the heat radiating part main flow path 30 and the other end of the three-way valve 34 are connected to the heat radiating part main flow path 30 on the fuel cell 14 side. The section of the heat radiating section main flow path 30 connecting both ends of the heat radiating section bypass flow path 32 is a section in which the heat radiating section main flow path 30 is bypassed by the heat radiating section bypass flow path 32, and is hereinafter referred to as a bypassed section 30a. I write.

  The heat radiating portion main flow path 30 has a heat insulating structure like the circulation flow path 16. On the other hand, at least a part of the heat radiating unit bypass flow path 32 does not have a heat insulating structure. That is, a heat insulating member is not provided on the outer periphery of at least a part of the bypass flow path 32. Thereby, more heat of the coolant is radiated in the heat dissipating unit bypass flow path 32 than in the bypassed section 30a corresponding thereto. That is, the heat dissipation amount of the heat dissipating unit bypass flow path 32 is larger than the heat dissipation amount of the bypassed section 30a.

  The three-way valve 34 adjusts the flow rate of the coolant flowing through the heat radiating unit bypass flow path 32 by the controller 60 instructing and adjusting the opening degree. When increasing the heat dissipation amount of the coolant, the control unit 60 sends a control signal so that the opening degree of the three-way valve 34 on the side of the heat dissipating unit bypass channel 32 is increased. On the other hand, when decreasing the heat dissipation amount of the coolant, the control unit 60 sends a control signal so that the opening degree of the three-way valve 34 on the side of the heat dissipating unit bypass flow path 32 becomes small.

  The control unit 60 recognizes the current state of the coolant circulation system 12, for example, the temperature and flow rate of the coolant, from detection signals detected by various sensors arranged in the circulation channel 16. And the control part 60 sends a control signal to each heater 24,26, each two-way valve 42,44, and the three-way valve 34 so that it may become the temperature and flow volume of the coolant calculated based on the set environmental condition. . The various sensors include a flow rate sensor 46, a fuel cell outlet temperature sensor 48, and a fine adjustment heater outlet temperature sensor 50 disposed in the circulation channel 16 between the fine adjustment heater 26 and the heat radiating portion 28.

  Next, the operation of the control unit 60 will be described. In the present embodiment, temperature control of the coolant when the flow rate of the coolant flowing through the fuel cell 14 is controlled to decrease will be described as an example.

  First, environmental conditions for evaluating the performance of the fuel cell 14 are set in the control unit 60. When the coolant flow rate calculated based on the set environmental conditions is smaller than the current value, the control unit 60 sends a control signal to the circulation flow path two-way valve 42 and the bypass flow path two-way valve 44. In response to a control signal from the control unit 60, the circulation flow path two-way valve 42 operates to reduce its opening, and the bypass flow path two-way valve 44 operates to decrease its opening. By the operation of these two-way valves 42 and 44, a larger amount of the coolant sent from the pump 20 flows through the bypass flow path 40, and the flow rate of the coolant flowing through the fuel cell 14 decreases.

  When the flow rate of the coolant flowing through the fuel cell 14 decreases, the flow rate of the coolant flowing through the fine adjustment heater 26 also decreases. Therefore, the controller 60 controls the amount of heating of the fine adjustment heater 26 in accordance with the decrease control of the flow rate of the coolant. Decrease. Generally, in order to reduce the heating amount of the heater, the temperature of the heating element of the heater is lowered. However, since this lowering takes time, the time from the start of control to the predetermined amount of heat, that is, the delay time Will occur. In the present embodiment, the heating element is cooled by the coolant, and the temperature thereof is lowered. When the flow rate of the coolant is decreased, the amount of heat received from the heating element per unit flow rate increases during the delay time. As a result, an excessive amount of heating is added to the coolant from the fine adjustment heater 26, and the temperature of the coolant flowing through the fuel cell 14 may rise (overshoot). However, the control unit 60 controls to decrease the heating amount of the fine adjustment heater 26 and increase the heat radiation amount of the heat radiation unit 28 so that the temperature of the coolant flowing through the fuel cell 14 does not increase. That is, the control unit 60 adjusts the opening degree of the three-way valve 34 so as to increase the flow rate of the coolant flowing through the heat radiating unit bypass flow path 32.

  The controller 60 adjusts the opening of the three-way valve 34 based on the detected temperature from the fine adjustment heater outlet temperature sensor 50. When the detected temperature from the fine adjustment heater outlet temperature sensor 50 is higher than the set temperature, the opening degree of the three-way valve 34 is adjusted so that the coolant flows through the heat radiating unit bypass flow path 32. Then, as the delay time elapses and the detected temperature approaches the set temperature, the opening degree of the three-way valve 34 is adjusted so as to decrease the flow rate of the coolant flowing through the heat radiating unit bypass flow path 32.

  According to the fuel cell evaluation device 10 according to the present embodiment, when the flow rate of the coolant in the coolant circulation system 12 is controlled to decrease, the heat of the coolant that has flowed through the fine adjustment heater 26 is controlled to be radiated. The temperature rise of the coolant sent to the fuel cell 14 can be prevented, and the temperature of the coolant can be controlled with higher accuracy.

  In the said embodiment, it is set as the structure where the heat insulation member is not provided in at least one part of the thermal radiation part bypass flow path 32, and about the case where the thermal radiation amount of the thermal radiation part bypass flow path 32 becomes larger than the thermal radiation amount of the to-be-passed area 30a. Although described, the present invention is not limited to this configuration. The surface area of the outer periphery of the heat radiating unit bypass flow path 32 is widened so that the heat of the coolant can be easily radiated, for example, a structure in which metal fins are provided on the outer periphery of the heat radiating unit bypass flow path 32 You may make it the thermal radiation amount of the flow path 32 become large.

  In the above embodiment, the case where the opening degrees of the circulation flow path two-way valve 42 and the bypass flow path two-way valve 44 are adjusted to adjust the flow rate of the coolant flowing through the fuel cell 14 has been described. It is not limited. A three-way valve may be arranged at the branch point 16a or the junction point 16b, the opening degree of the three-way valve may be adjusted, and the flow rate of the coolant flowing through the fuel cell 14 may be adjusted. Further, the flow rate of the coolant flowing through the fuel cell 14 may be adjusted by adjusting the rotational speed of the pump 20 without adjusting the opening of the valve.

  In the above embodiment, the case where the three-way valve 34 is used to adjust the flow rate of the coolant flowing through the heat dissipating unit bypass flow path 32 has been described, but the present invention is not limited to this configuration. Even if a two-way valve is arranged in each of the bypassed section 30a and the heat radiating part bypass flow path 32, the opening degree of these two-way valves is adjusted, and the flow rate of the coolant flowing through the heat radiating part bypass flow path 32 is adjusted. Good.

It is a figure which shows schematic structure of the cooling fluid circulation system of the fuel cell evaluation apparatus which concerns on this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Fuel cell evaluation apparatus, 12 Coolant circulation system, 14 Fuel cell, 16 Circulation flow path, 18 Heat exchanger, 20 Pump, 22 Tank, 24 Rough adjustment heater, 26 Fine adjustment heater, 28 Radiation part, 30 Radiation part main Flow path, 32 Heat radiation part bypass flow path, 34 Three-way valve, 40 Bypass flow path, 42 Circulation flow path two-way valve, 44 Bypass flow path two-way valve, 46 Flow rate sensor, 48 Fuel cell outlet temperature sensor, 50 Fine adjustment heater Outlet temperature sensor, 60 controller.

Claims (2)

A fuel cell evaluation device for managing the temperature of a fuel cell with a coolant circulation system and evaluating the performance of the fuel cell,
The coolant circulation system is
Flow rate adjusting means for adjusting the flow rate of the coolant flowing through the fuel cell;
Heating means for heating the coolant in an adjustable manner;
A heat dissipating means provided between the heating means and the fuel cell for dissipating heat of the coolant in an adjustable manner;
Have
When the flow rate of the coolant is controlled to be decreased by the flow rate adjusting unit, the controller has a controller that decreases the amount of heat generated by the heating unit and increases the amount of heat released by the heat radiating unit.
A fuel cell evaluation apparatus. The fuel cell evaluation apparatus according to claim 1,
The heat dissipation means is
A first flow path through which a coolant flows from the heating means to the fuel cell;
A second flow path in which the coolant flows bypassing at least a part of the first flow path;
An adjustment valve for adjusting the flow rate of the coolant flowing through the second flow path;
Have
The heat dissipation amount of the second flow path is greater than the heat dissipation amount of the first flow path corresponding to the second flow path.
A fuel cell evaluation apparatus.

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