Fuel cell system

Abstract

The present invention provides a fuel cell system capable of accurately determining the replacement timing of an ion exchanger. The fuel cell system includes: a first ion exchanger; a first fuel cell stack and a second fuel cell stack; a first temperature acquisition unit and a second temperature acquisition unit; a first power generation time acquisition unit and a second power generation time acquisition unit; a supply path; an ion concentration estimation unit that estimates the ion concentration of the refrigerant based on at least one of the temperature of the refrigerant and the power generation time; a determination unit that determines the replacement timing of the first ion exchanger based on the ion concentration estimated by the ion concentration estimation unit; and a control unit, wherein the first refrigerant flow path and the second refrigerant flow path are arranged in series or in parallel.

Description

Technical Field

[0001] The present invention relates to a fuel cell system. Background Art

[0002] Conventionally, a metal separator has been used in a stacked cell. If metal ions elute from the metal separator and the metal ions accumulate in the stacked cell, there is a problem such as a short circuit in the stacked cell. To solve such a problem, a cooling device is known, which includes: an ion exchange resin that can remove metal ions from the cooling water of the stacked cell; a resin water passage that encloses the ion exchange resin and allows the cooling water to pass through the ion exchange resin; a bypass passage that branches from the resin water passage and bypasses the ion exchange resin; and an opening / closing portion that closes the bypass passage according to the conductive state of the cooling water (for example, refer to International Publication No. 2014 / 174982). Summary of the Invention

[0003] In order to effectively remove metal ions, it is necessary to provide one ion exchanger for each cell. However, if a plurality of ion exchangers are used, the replacement timing is different for each ion exchanger, and thus it is difficult to accurately determine the replacement timing of all the ion exchangers.

[0004] The solution of the present invention has been completed in consideration of such a situation, and one of the purposes is to provide a fuel cell system capable of accurately determining the replacement timing of an ion exchanger.

[0005] In order to solve the above problems and achieve the above object, the present invention adopts the following solution.

[0006] (1) A fuel cell system according to an aspect of the present invention includes: a plurality of fuel cell stacks; a first ion exchanger that reduces the ion concentration in a refrigerant; a temperature acquisition unit that acquires the temperature of the refrigerant in the plurality of refrigerant flow paths on the downstream side of the plurality of fuel cell stacks in the plurality of refrigerant flow paths that supply the refrigerant to the plurality of fuel cell stacks respectively; a power generation time acquisition unit that acquires the power generation time of the plurality of fuel cell stacks; a supply path that supplies the refrigerant discharged from the plurality of fuel cell stacks to the first ion exchanger; an ion concentration estimation unit that estimates the ion concentration of the refrigerant based on at least one of the temperature of the refrigerant acquired by the temperature acquisition unit and the power generation time of the plurality of fuel cell stacks acquired by the power generation time acquisition unit; a determination unit that determines the replacement timing of the first ion exchanger based on the ion concentration estimated by the ion concentration estimation unit; and a control unit that controls the plurality of fuel cell stacks, the temperature acquisition unit, the power generation time acquisition unit, the ion concentration estimation unit, and the determination unit, and the plurality of refrigerant flow paths are arranged in series or in parallel.

[0007] (2)On the basis of the solution in (1) above, it may also be that the ion concentration estimation unit estimates that the higher the temperature of the refrigerant of the fuel cell stack obtained by the temperature acquisition unit, the more the amount of ions dissolved from the refrigerant, and the determination unit determines the replacement timing of the first ion exchanger according to the cumulative value of the ion concentration estimated from the temperature of the refrigerant obtained by the temperature acquisition unit.

[0008] (3)On the basis of the solution in (1) or (2) above, it may also be that the fuel cell system includes: a pressure feeding unit that supplies the refrigerant according to the required output of the plurality of fuel cell stacks; a stop time acquisition unit that acquires the stop time of the plurality of fuel cell stacks; and an external gas temperature information acquisition unit that acquires the external gas temperature information during the stop of the fuel cell stack, and the control unit determines the starting discharge amount of the refrigerant pumped by the pressure feeding unit at the start of the plurality of fuel cell stacks based on at least one of the stop time and the external gas temperature information, and the pressure feeding unit performs control based on the starting discharge amount prior to the pressure feeding control corresponding to the required output at the start of the plurality of fuel cell stacks.

[0009] (4)On the basis of the solution in (3) above, it may also be that the plurality of fuel cell stacks are arranged in parallel, and the fuel cell system includes: a branch flow path that selectively branches the refrigerant in the supply path and returns the refrigerant to the refrigerant flow path on the upstream side of the plurality of fuel cell stacks; and a second ion exchanger that is provided in the branch flow path, and the control unit controls the flow time of the refrigerant flowing through the branch flow path at least based on the stop time at the start of the plurality of fuel cell stacks.

[0010] (5)On the basis of the solution in (3) above, it may also be that the plurality of fuel cell stacks are arranged in parallel, and the fuel cell system includes: a branch flow path that selectively branches the refrigerant in the supply path and returns the refrigerant to the refrigerant flow path on the upstream side of the plurality of fuel cell stacks; and a second ion exchanger that is provided in the branch flow path, and the control unit controls the flow time of the refrigerant flowing through the branch flow path at least based on the power generation time at the stop of the plurality of fuel cell stacks.

[0011] (6)On the basis of the solution in (4) above, it may also be that the multiple fuel cell stacks include a first fuel cell stack and a second fuel cell stack, and when there is a difference of a specified value or more between the power generation time of the first fuel cell stack at startup obtained by the power generation time acquisition unit and the power generation time of the second fuel cell stack at startup obtained by the power generation time acquisition unit, the control unit circulates the refrigerant between the first fuel cell stack and the second fuel cell stack.

[0012] (7)On the basis of the solution in (5) above, it may also be that the multiple fuel cell stacks include a first fuel cell stack and a second fuel cell stack, and when there is a difference of a specified value or more between the stop time of the first fuel cell stack obtained by the stop time acquisition unit and the stop time of the second fuel cell stack obtained by the stop time acquisition unit, the control unit circulates the refrigerant between the first fuel cell stack and the second fuel cell stack.

[0013] According to (1) above, the ion concentration estimation unit estimates the ion concentration of the refrigerant based on at least one of the temperature of the refrigerant obtained by the temperature acquisition unit and the power generation time of the multiple fuel cell stacks obtained by the power generation time acquisition unit, and the determination unit determines the replacement timing of the first ion exchanger based on the ion concentration estimated by the ion concentration estimation unit, thereby enabling the replacement timing of the ion exchanger to be determined with high accuracy.

[0014] In the case of (2) above, the ion concentration estimation unit estimates that the higher the temperature of the refrigerant obtained by the temperature acquisition unit, the more the ion dissolution amount from the refrigerant, and the determination unit determines the replacement timing of the first ion exchanger according to the cumulative value of the ion concentration estimated from the temperature of the refrigerant obtained by the temperature acquisition unit. Thus, the replacement timing of the ion exchanger can be determined with high accuracy.

[0015] In the case of (3) above, based on at least one of the stop time and the external gas temperature information, the start-up discharge amount of the refrigerant pumped by the pumping unit at the start-up of the multiple fuel cell stacks is determined, and the pumping unit performs control based on the start-up discharge amount prior to the pumping control corresponding to the required output at the start-up of the multiple fuel cell stacks, thereby enabling the deviation of the ion concentration contained in the refrigerant to be reduced in the multiple fuel cell stacks. Thus, the replacement timing of the ion exchanger can be determined with high accuracy.

[0016] In the case of (4) above, at the start-up of the fuel cell stack, the circulation time for the refrigerant to flow through the branch flow path is controlled based on at least the stop time, thereby enabling the replacement timing of the ion exchanger to be determined with high accuracy.

[0017] In the case of (5) above, when the fuel cell stack is stopped, the circulation time for allowing the refrigerant to flow through the branch flow path is controlled based at least on the power generation time, whereby the replacement timing of the ion exchanger can be determined with high accuracy.

[0018] In the case of (6) above, when there is a difference equal to or greater than a specified value between the power generation time of the first fuel cell stack at startup obtained by the power generation time acquisition unit and the power generation time of the second fuel cell stack at startup obtained by the power generation time acquisition unit, the refrigerant is circulated between the first fuel cell stack and the second fuel cell stack, whereby the deviation in the concentration of ions contained in the refrigerant can be reduced in the first fuel cell stack and the second fuel cell stack. Thereby, the replacement timing of the ion exchanger can be determined with high accuracy.

[0019] In the case of (7) above, when there is a difference equal to or greater than a specified value between the stop time of the first fuel cell stack obtained by the stop time acquisition unit and the stop time of the second fuel cell stack obtained by the stop time acquisition unit, the refrigerant is circulated between the first fuel cell stack and the second fuel cell stack, whereby the deviation in the concentration of ions contained in the refrigerant can be reduced in the first fuel cell stack and the second fuel cell stack. Thereby, the replacement timing of the ion exchanger can be determined with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 FIG. is a schematic diagram showing a fuel cell system according to an embodiment of the present invention.

[0021] Figure 2 FIG. is an example of a system flow showing a method of operating a fuel cell system according to an embodiment of the present invention.

[0022] Figure 3 FIG. is an example of a system flow showing a method of operating a fuel cell system according to an embodiment of the present invention.

[0023] Figure 4 FIG. is a schematic diagram showing a fuel cell system according to an embodiment of the present invention.

[0024] Figure 5 FIG. is an example of a system flow showing a method of operating a fuel cell system according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0026] Figure 1It is a schematic diagram showing the fuel cell system 10 in the embodiment. The fuel cell system 10 can be mounted on a vehicle, for example. In addition to the fuel cell system 10, the vehicle may include devices such as a power storage device, an electric motor, a radiator, and a refrigerant tank, for example. The vehicle may also include the fuel cell system 10 and a control device 100 that controls other devices. The control device 100 of the vehicle may also communicate signals with the control unit (control device (FC control device)) 30 of the fuel cell system 10.

[0027] The fuel cell system 10 includes a first fuel cell (FC) stack 11, a second fuel cell (FC) stack 12, a first ion exchanger 13, a first temperature acquisition unit 14, a second temperature acquisition unit 15, a first power generation time acquisition unit 16, a second power generation time acquisition unit 17, an ion concentration estimation unit 18, a determination unit 19, a refrigerant tank 20, a supply path 21, and an FC control device 30 as an example of a control unit. The FC control device 30 is connected to each component of the fuel cell system 10 via signal lines. The fuel cell system 10 includes a fuel tank and a gas pump (not shown). In the fuel cell system 10, a cooling system circuit including the first fuel cell stack 11, the second fuel cell stack 12, the first ion exchanger 13, the first temperature acquisition unit 14, the second temperature acquisition unit 15, the first power generation time acquisition unit 16, the second power generation time acquisition unit 17, the ion concentration estimation unit 18, the determination unit 19, and the supply path 21 is formed. The fuel cell system 10 may also include a first pumping unit 22, a first valve mechanism 23, a first stop time acquisition unit 24, a second stop time acquisition unit 25, and an external gas temperature information acquisition unit 26.

[0028] The first fuel cell stack 11 and the second fuel cell stack 12 are, for example, polymer electrolyte fuel cells. The polymer electrolyte fuel cell includes, for example, a plurality of stacked fuel cell monomers and a pair of end plates sandwiching the stack of the plurality of fuel cell monomers. The fuel cell monomer includes an electrolyte electrode structure and a pair of separators sandwiching the electrolyte electrode structure. The electrolyte electrode structure includes a polymer electrolyte membrane and a fuel electrode and an oxygen electrode sandwiching the polymer electrolyte membrane. The polymer electrolyte membrane includes a cation exchange membrane or the like. The fuel electrode (anode) includes an anode catalyst and a gas diffusion layer or the like. The oxygen electrode (cathode) includes a cathode catalyst and a gas diffusion layer or the like.

[0029] In the first fuel cell stack 11 and the second fuel cell stack 12, power generation is performed through a catalytic reaction between the fuel gas supplied from the fuel tank to the anode and the oxidant gas such as air containing oxygen supplied from the air pump to the cathode. The remaining gas components and the like that are supplied to the fuel cell stack and not used are discharged through a prescribed flow path. The first fuel cell stack 11 and the second fuel cell stack 12 are arranged in parallel. In the case where the fuel cell system 10 is mounted on a vehicle, for example, the output of the second fuel cell stack 12 is adjusted by throttle operation.

[0030] The first ion exchanger 13 is connected to the first fuel cell stack 11 and the second fuel cell stack 12 via the supply path 21. The first ion exchanger 13 includes an ion exchange resin capable of removing impurity ions in the refrigerant. The first ion exchanger 13 removes the impurity ions in the refrigerant flowing in the fuel cell system 10 to reduce the ion concentration of the refrigerant. Specifically, the impurity ions in the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 and introduced via the supply path 21 are removed.

[0031] The first temperature acquisition unit 14 and the second temperature acquisition unit 15 are temperature detectors such as thermometers. The first temperature acquisition unit 14 is provided on the downstream side of the first fuel cell stack 11 in the first refrigerant flow path 27 that supplies the refrigerant to the first fuel cell stack 11, and acquires the temperature of the refrigerant at that position. The second temperature acquisition unit 15 is provided on the downstream side of the second fuel cell stack 12 in the second refrigerant flow path 28 that supplies the refrigerant to the second fuel cell stack 12, and acquires the temperature of the refrigerant at that position. The first refrigerant flow path 27 and the second refrigerant flow path 28 are arranged in parallel. The first refrigerant flow path 27 and the second refrigerant flow path 28 may also be arranged in series.

[0032] The first power generation time acquisition unit 16 is connected to the first fuel cell stack 11 and acquires the power generation time of the first fuel cell stack 11. The second power generation time acquisition unit 17 is connected to the second fuel cell stack 12 and acquires the power generation time of the second fuel cell stack 12.

[0033] The ion concentration estimation unit 18 is, for example, an ion concentration sensor. The ion concentration estimation unit 18 estimates the ion concentration of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 based on at least one of the temperature of the refrigerant acquired by the first temperature acquisition unit 14, the temperature of the refrigerant acquired by the second temperature acquisition unit 15, the power generation time of the first fuel cell stack 11 acquired by the first power generation time acquisition unit 16, and the power generation time of the second fuel cell stack 12 acquired by the second power generation time acquisition unit 17. The ion concentration of the refrigerant is estimated based on the conductivity of the refrigerant.

[0034] The determination unit 19 determines the replacement timing of the first ion exchanger 13 based on the ion concentration of the refrigerant estimated by the ion concentration estimation unit 18.

[0035] The refrigerant tank 20 is filled with a refrigerant for cooling the fuel cell system 10. The refrigerant tank 20 supplies the refrigerant into the cooling system circuit of the fuel cell system 10.

[0036] The supply path 21 is connected to the first fuel cell stack 11 and the second fuel cell stack 12, and supplies the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 to the first ion exchanger 13.

[0037] The first pumping unit 22 is, for example, an air pump. The first pumping unit 22 is connected to the refrigerant tank 20 and the first valve mechanism 23. The first pumping unit 22 supplies the refrigerant in the refrigerant tank 20 into the cooling system circuit according to the required output of the first fuel cell stack 11 and the second fuel cell stack 12.

[0038] The first valve mechanism 23 is connected to the refrigerant tank 20, the first fuel cell stack 11, and the second fuel cell stack 12. The first valve mechanism 23 includes, for example, a control valve that switches the flow rate Q, pressure P, etc. of the refrigerant through the control of the FC control device 30 between the refrigerant tank 20 and the first fuel cell stack 11 and the second fuel cell stack 12, and a check valve that prohibits the flow of the refrigerant from the first fuel cell stack 11 and the second fuel cell stack 12 side to the refrigerant tank 20.

[0039] The first stop time acquisition unit 24 is connected to the first fuel cell stack 11. The first stop time acquisition unit 24 acquires the stop time of the first fuel cell stack 11. The second stop time acquisition unit 25 is connected to the second fuel cell stack 12. The second stop time acquisition unit 25 acquires the stop time of the second fuel cell stack 12.

[0040] The external gas temperature information acquisition unit 26 is a temperature measuring device such as a thermometer. The external gas temperature information acquisition unit 26 acquires the external gas temperature information (outside air temperature) during the stop of the first fuel cell stack 11 and the second fuel cell stack 12.

[0041] The FC control device 30 comprehensively controls the operations of the first fuel cell stack 11, the second fuel cell stack 12, the first temperature acquisition unit 14, the second temperature acquisition unit 15, the first power generation time acquisition unit 16, the second power generation time acquisition unit 17, the ion concentration estimation unit 18, the determination unit 19, the first pumping unit 22, the first valve mechanism 23, the first stop time acquisition unit 24, the second stop time acquisition unit 25, the external gas temperature information acquisition unit 26, etc.

[0042] A method for operating the fuel cell system 10 will be described.

[0043] In the fuel cell system 10, the ion concentration estimation unit 18 estimates that the higher the temperature of the refrigerant of the first fuel cell stack 11 and the second fuel cell stack 12 obtained by the first temperature acquisition unit 14 and the second temperature acquisition unit 15, the more ions are eluted from the refrigerant. The determination unit 19 determines the replacement timing of the first ion exchanger 13 based on the cumulative value of the ion concentration estimated from the temperatures of the refrigerants of the first fuel cell stack 11 and the second fuel cell stack 12 obtained by the first temperature acquisition unit 14 and the second temperature acquisition unit 15. The FC control device 30 determines the starting discharge amount of the refrigerant pumped by the first pumping unit 22 at the start of the first fuel cell stack 11 and the second fuel cell stack 12 based on at least one of the stop time obtained by the first stop time acquisition unit 24 and the second stop time acquisition unit 25 and the outside gas temperature information obtained by the outside gas temperature information acquisition unit 26. And the first pumping unit 22 preferentially performs control based on the starting discharge amount at the start of the first fuel cell stack 11 and the second fuel cell stack 12 over the pumping control corresponding to the required output.

[0044] Describe a specific example of the operation method of the fuel cell system 10.

[0045] Figure 2 It is the first example of the system flow showing the operation method of the fuel cell system 10.

[0046] At T0 to T1, the first fuel cell stack 11 and the second fuel cell stack 12 are stopped. Therefore, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 is low. Therefore, the ion concentration estimation unit 18 estimates that almost no ions are eluted from the first fuel cell stack 11 and the second fuel cell stack 12. Therefore, the remaining time until the replacement of the first ion exchanger 13 hardly changes.

[0047] At T1, the first fuel cell stack 11 and the second fuel cell stack 12 are started. At T1 to T2, if the power generation amount of the first fuel cell stack 11 and the second fuel cell stack 12 increases, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 becomes higher. The ion concentration estimation unit 18 estimates that the higher the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12, the more the total elution amount of the ions eluted from the first fuel cell stack 11 and the ions eluted from the second fuel cell stack 12 becomes. Along with this, the remaining time until the replacement of the first ion exchanger 13 becomes shorter.

[0048] Between T2 and T3, the power generation of the first fuel cell stack 11 becomes lower compared to that between T1 and T2, and the temperature of the refrigerant discharged from the first fuel cell stack 11 becomes lower. On the other hand, compared to T1 - T2, the power generation of the second fuel cell stack 12 further increases, and the temperature of the refrigerant discharged from the second fuel cell stack 12 further increases. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 increases. Along with this, the remaining time until the replacement of the first ion exchanger 13 further shortens.

[0049] Between T3 and T4, if the power generation of the first fuel cell stack 11 further decreases, the temperature of the refrigerant discharged from the first fuel cell stack 11 further decreases. The power generation of the second fuel cell stack 12 decreases, and the temperature of the refrigerant discharged from the second fuel cell stack 12 decreases. Between T3 and T4, the power generation of the second fuel cell stack 12 is less than that of the first fuel cell stack 11. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 decreases. Along with this, the remaining time until the replacement of the first ion exchanger 13 hardly changes.

[0050] Between T4 and T5, if the power generation of the first fuel cell stack 11 and the second fuel cell stack 12 increases, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 increases. Between T4 and T5, the power generation of the second fuel cell stack 12 is less than that of the first fuel cell stack 11. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 increases. Along with this, the remaining time until the replacement of the first ion exchanger 13 shortens.

[0051] Between T5 and T6, if the power generation of the first fuel cell stack 11 and the second fuel cell stack 12 decreases, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 decreases. Between T5 and T6, the power generation of the second fuel cell stack 12 is less than that of the first fuel cell stack 11. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 decreases. Along with this, the remaining time until the replacement of the first ion exchanger 13 hardly changes.

[0052] In T6 - T7, if the power generation of the first fuel cell stack 11 and the second fuel cell stack 12 increases, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 becomes higher. In T6 - T7, the power generation of the second fuel cell stack 12 is less than that of the first fuel cell stack 11. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 increases. Along with this, the remaining time until the replacement of the first ion exchanger 13 becomes shorter.

[0053] In T7 - T8, if the power generation of the first fuel cell stack 11 and the second fuel cell stack 12 decreases, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 becomes lower. In T7 - T8, the power generation of the second fuel cell stack 12 is less than that of the first fuel cell stack 11. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 decreases. Along with this, the remaining time until the replacement of the first ion exchanger 13 hardly changes.

[0054] In T8 - T9, the power generation of the first fuel cell stack 11 increases, and the temperature of the refrigerant discharged from the first fuel cell stack 11 becomes higher. On the other hand, the power generation of the second fuel cell stack 12 remains low and constant, so the temperature of the refrigerant discharged from the second fuel cell stack 12 remains low and constant. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 decreases. Along with this, the remaining time until the replacement of the first ion exchanger 13 hardly changes.

[0055] In T9 - T 10 , if the power generation of the first fuel cell stack 11 and the second fuel cell stack 12 decreases, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 becomes lower. In T9 - T 10 , the power generation of the second fuel cell stack 12 is more than that of the first fuel cell stack 11. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 decreases. Along with this, the remaining time until the replacement of the first ion exchanger 13 hardly changes.

[0056] In T 10 ~T 11, if the power generation of the first fuel cell stack 11 and the second fuel cell stack 12 increases, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 becomes higher. At T 10 ~T 11 , the power generation of the second fuel cell stack 12 is larger than that of the first fuel cell stack 11. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 increases. Along with this, the remaining time until the replacement of the first ion exchanger 13 becomes shorter.

[0057] At T 10 ~T 11 , when the sum of the power generation time of the first fuel cell stack 11 and the power generation time of the second fuel cell stack 12 is equal to or greater than a specified value 1 as shown in the following formula (1), the remaining time until the replacement of the first ion exchanger 13 is notified.

[0058] (Power generation time of the first fuel cell stack × Temperature frequency coefficient 1) + (Power generation time of the second fuel cell stack × Temperature frequency coefficient 2) ≥ Specified value 1 (1)

[0059] At T 11 ~T 12 , if the power generation of the first fuel cell stack 11 and the second fuel cell stack 12 decreases, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 becomes lower. At T 11 ~T 12 , the power generation of the second fuel cell stack 12 is smaller than that of the first fuel cell stack 11. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 decreases. Along with this, the remaining time until the replacement of the first ion exchanger 13 hardly changes.

[0060] At T 12 ~T 13 , if the power generation of the first fuel cell stack 11 and the second fuel cell stack 12 increases, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 becomes higher. At T 12 ~T 13 , the power generation of the first fuel cell stack 11 is approximately the same as that of the second fuel cell stack 12. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 increases. Along with this, the remaining time until the replacement of the first ion exchanger 13 becomes shorter.

[0061] At T13 to T 14 14 , if the power generation of the first fuel cell stack 11 and the second fuel cell stack 12 decreases, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 becomes lower. At T 13 to T 14 14 , the power generation of the second fuel cell stack 12 is less than that of the first fuel cell stack 11. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 decreases. Along with this, the remaining time until the replacement of the first ion exchanger 13 becomes slightly shorter.

[0062] At T 14 to T 15 15 , if the power generation of the first fuel cell stack 11 is less than that at T 13 to T 14 14 , the temperature of the refrigerant discharged from the first fuel cell stack 11 becomes lower. The power generation of the second fuel cell stack 12 is the same as that at T 13 to T 14 14 , and the temperature of the refrigerant discharged from the second fuel cell stack 12 is the same as that at T 13 to T 14 14 . At T 14 to T 15 15 , the power generation of the first fuel cell stack 11 is approximately the same as that of the second fuel cell stack 12. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 decreases. Along with this, the remaining time until the replacement of the first ion exchanger 13 becomes slightly shorter.

[0063] At T 14 to T 15 15 , when the sum of the power generation time of the first fuel cell stack 11 and the power generation time of the second fuel cell stack 12 is equal to or greater than a specified value 2 as shown in the following formula (2), replacement of the first ion exchanger 13 is required.

[0064] (Power generation time of the first fuel cell stack × Temperature frequency coefficient 1) + (Power generation time of the second fuel cell stack × Temperature frequency coefficient 2) ≥ Specified value 2 (2)

[0065] Figure 3 Figure 3 is the second example of the system flow showing the operation method of the fuel cell system 10.

[0066] Between T0 and T1, the first fuel cell stack 11 and the second fuel cell stack 12 stop. Therefore, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 is low. The stop time of the first fuel cell stack 11 and the second fuel cell stack 12 (stop time) becomes long. Between T0 and T1, the remaining time until the replacement of the first ion exchanger 13 hardly changes.

[0067] Between T1 and T2, before starting the first fuel cell stack 11 and the second fuel cell stack 12, the air pump as the first pumping unit 22 is operated to supply the refrigerant in the refrigerant tank 20 into the cooling system circuit, and the ion exchange resin of the first ion exchanger 13 performs ion exchange. Therefore, the ion concentration estimation unit 18 estimates that the amount of ion elution from the first fuel cell stack 11 and the second fuel cell stack 12 becomes less. Along with this, the remaining time until the replacement of the first ion exchanger 13 becomes short. Between T1 and T2, it is estimated that the total amount of ion elution discharged from the first fuel cell stack 11 and the amount of ion elution discharged from the second fuel cell stack 12 becomes constant in the middle, and therefore the change rate of the decrease amount of the remaining time until the replacement of the first ion exchanger 13 becomes small.

[0068] Between T2 and T3, the power generation amount of the first fuel cell stack 11 increases, and the temperature of the refrigerant discharged from the first fuel cell stack 11 becomes high. On the other hand, the power generation amount of the second fuel cell stack 12 slightly decreases, and the temperature of the refrigerant discharged from the second fuel cell stack 12 slightly decreases. And the supply amount of the refrigerant based on the first pumping unit 22 into the cooling system circuit is increased. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ion elution discharged from the first fuel cell stack 11 and the amount of ion elution discharged from the second fuel cell stack 12 increases. Along with this, the remaining time until the replacement of the first ion exchanger 13 becomes short.

[0069] Between T3 and T4, the power generation amount of the first fuel cell stack 11 decreases, and the temperature of the refrigerant discharged from the first fuel cell stack 11 becomes low. On the other hand, the power generation amount of the second fuel cell stack 12 increases, and the temperature of the refrigerant discharged from the second fuel cell stack 12 becomes high. And the supply amount of the refrigerant based on the first pumping unit 22 into the cooling system circuit is decreased. Between T3 and T4, the increase amount of the power generation amount of the second fuel cell stack 12 and the temperature of the refrigerant discharged from the second fuel cell stack 12 is less than the decrease amount of the power generation amount of the first fuel cell stack 11 and the temperature of the refrigerant discharged from the first fuel cell stack 11. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ion elution discharged from the first fuel cell stack 11 and the amount of ion elution discharged from the second fuel cell stack 12 increases until the middle, and then the total amount of ion elution decreases. Along with this, the remaining time until the replacement of the first ion exchanger 13 becomes short.

[0070] In T4 - T5, if the power generation amounts of the first fuel cell stack 11 and the second fuel cell stack 12 decrease, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 becomes lower. Also, the supply amount of the refrigerant based on the first pumping unit 22 to the cooling system circuit is decreased. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the amount of ions eluted from the second fuel cell stack 12 decreases. Along with this, the remaining time until the replacement of the first ion exchanger 13 becomes shorter.

[0071] In T5 - T6, if the power generation amounts of the first fuel cell stack 11 and the second fuel cell stack 12 increase, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 becomes higher. In T5 - T6, the power generation amount of the second fuel cell stack 12 is less than that of the first fuel cell stack 11. Also, the supply amount of the refrigerant based on the first pumping unit 22 to the cooling system circuit is increased. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the amount of ions eluted from the second fuel cell stack 12 decreases. Along with this, the remaining time until the replacement of the first ion exchanger 13 becomes shorter.

[0072] In T6 - T7, the power generation amount of the first fuel cell stack 11 increases, and the temperature of the refrigerant discharged from the first fuel cell stack 11 becomes higher. On the other hand, the power generation amount of the second fuel cell stack 12 decreases, and the temperature of the refrigerant discharged from the second fuel cell stack 12 becomes lower. Also, the supply amount of the refrigerant based on the first pumping unit 22 to the cooling system circuit is increased. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the amount of ions eluted from the second fuel cell stack 12 slightly increases. Along with this, the remaining time until the replacement of the first ion exchanger 13 slightly becomes shorter.

[0073] In T7 - T8, if the power generation amounts of the first fuel cell stack 11 and the second fuel cell stack 12 decrease, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 becomes lower. In T7 - T8, the rate of change of the power generation amount of the second fuel cell stack 12 is smaller than the rate of change of the power generation amount of the first fuel cell stack 11. Also, the supply amount of the refrigerant based on the first pumping unit 22 to the cooling system circuit is decreased. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the amount of ions eluted from the second fuel cell stack 12 slightly decreases. Along with this, the remaining time until the replacement of the first ion exchanger 13 hardly changes.

[0074] In the period from T8 to T9, if the power generation amounts of the first fuel cell stack 11 and the second fuel cell stack 12 hardly change, the temperatures of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 hardly change. Also, the supply amount of the refrigerant into the cooling system circuit by the first pumping unit 22 is made to hardly change. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the amount of ions eluted from the second fuel cell stack 12 hardly change. Along with this, the remaining time until the replacement of the first ion exchanger 13 hardly changes.

[0075] In the period from T9 to T 10 , if the power generation amounts of the first fuel cell stack 11 and the second fuel cell stack 12 increase, the temperatures of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 become higher. In the period from T9 to T 10 , the rate of change of the power generation amount of the second fuel cell stack 12 is smaller than the rate of change of the power generation amount of the first fuel cell stack 11. Also, the supply amount of the refrigerant into the cooling system circuit by the first pumping unit 22 is slightly increased. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the amount of ions eluted from the second fuel cell stack 12 increases. Along with this, the remaining time until the replacement of the first ion exchanger 13 becomes shorter.

[0076] In the period from T 10 to T 11 , the power generation amount of the first fuel cell stack 11 decreases, and the temperature of the refrigerant discharged from the first fuel cell stack 11 becomes lower. On the other hand, the power generation amount of the second fuel cell stack 12 slightly increases, and the temperature of the refrigerant discharged from the second fuel cell stack 12 slightly becomes higher. Also, the supply amount of the refrigerant into the cooling system circuit by the first pumping unit 22 is decreased. In the period from T 10 to T 11 , the rate of change of the power generation amount of the second fuel cell stack 12 is smaller than the rate of change of the power generation amount of the first fuel cell stack 11. Also, the supply amount of the refrigerant into the cooling system circuit by the first pumping unit 22 is decreased. Therefore, the ion concentration estimation unit 18 estimates that in the period from T 10 to T 11 the total amount of ions eluted from the first fuel cell stack 11 and the amount of ions eluted from the second fuel cell stack 12 increases. Along with this, the remaining time until the replacement of the first ion exchanger 13 becomes shorter.

[0077] In the period from T 10 to T 11, when the total of the power generation time of the first fuel cell stack 11 and the power generation time of the second fuel cell stack 12 shown in the following formula (1) is 1 or more of a specified value, the remaining time until replacement of the first ion exchanger 13 is notified.

[0078] (Power generation time of the first fuel cell stack × Temperature frequency coefficient 1) + (Power generation time of the second fuel cell stack × Temperature frequency coefficient 2) ≥ Specified value 1 (1)

[0079] At T 11 ~T 12 , if the power generation amounts of the first fuel cell stack 11 and the second fuel cell stack 12 increase, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 becomes higher. At T 11 ~T 12 , the power generation amount of the second fuel cell stack 12 is less than the power generation amount of the first fuel cell stack 11. Also, the supply amount of the refrigerant based on the first pumping unit 22 into the cooling system circuit is increased. Therefore, the ion concentration estimation unit 18 estimates that the amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 becomes less. Along with this, the remaining time until replacement of the first ion exchanger 13 becomes shorter.

[0080] At T 12 ~T 13 , the power generation amount of the first fuel cell stack 11 and the temperature of the refrigerant discharged from the first fuel cell stack 11 hardly change. On the other hand, the power generation amount of the second fuel cell stack 12 slightly decreases, and the temperature of the refrigerant discharged from the second fuel cell stack 12 slightly decreases. Also, the supply amount of the refrigerant based on the first pumping unit 22 into the cooling system circuit is maintained in an increased and constant state. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 increases. Along with this, the remaining time until replacement of the first ion exchanger 13 becomes shorter.

[0081] At T 13 ~T 14 , if the power generation amounts of the first fuel cell stack 11 and the second fuel cell stack 12 decrease, the temperature of the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 becomes lower. At T 13 ~T 14, the rate of change in the power generation of the second fuel cell stack 12 is smaller than the rate of change in the power generation of the first fuel cell stack 11. Also, the supply amount of the refrigerant based on the first pump 22 into the cooling system circuit is slightly reduced. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 increases. Along with this, the remaining time until the replacement of the first ion exchanger 13 becomes slightly shorter.

[0082] At T 14 ~T 15 , if the power generation of the first fuel cell stack 11 is less than that at T 13 ~T 14 , the temperature of the refrigerant discharged from the first fuel cell stack 11 becomes lower. If the power generation of the second fuel cell stack 12 is less than that at T 13 ~T 14 , the temperature of the refrigerant discharged from the second fuel cell stack 12 becomes lower. At T 14 ~T 15 , the rate of change in the power generation of the second fuel cell stack 12 is less than the rate of change in the power generation of the first fuel cell stack 11. Also, the supply amount of the refrigerant based on the first pump 22 into the cooling system circuit is reduced. Therefore, the ion concentration estimation unit 18 estimates that the total amount of ions eluted from the first fuel cell stack 11 and the second fuel cell stack 12 decreases. Along with this, the remaining time until the replacement of the first ion exchanger 13 becomes shorter.

[0083] At T 14 ~T 15 , when the sum of the power generation time of the first fuel cell stack 11 and the power generation time of the second fuel cell stack 12 is 2 or more as shown in the following formula (2), replacement of the first ion exchanger 13 is required.

[0084] (Power generation time of the first fuel cell stack × Temperature frequency coefficient 1) + (Power generation time of the second fuel cell stack × Temperature frequency coefficient 2) ≥ Specified value 2 (2)

[0085] As described above, the fuel cell system 10 of the embodiment uses the ion concentration estimation unit 18 to estimate the ion concentration based on at least one of the temperature of the refrigerant obtained by the first temperature acquisition unit 14 and the second temperature acquisition unit 15 and the power generation time obtained by the first power generation time acquisition unit 16 and the second power generation time acquisition unit 17, and uses the determination unit 19 to determine the replacement timing of the first ion exchanger 13 based on the ion concentration estimated by the ion concentration estimation unit 18. Thus, the replacement timing of the first ion exchanger 13 can be determined with high accuracy. As a result, the first ion exchanger 13 can be used up until the end, improving convenience.

[0086] The ion concentration estimation unit 18 estimates that the higher the temperature of the refrigerant obtained by the first temperature acquisition unit 14 and the second temperature acquisition unit 15, the more the amount of ion dissolution. The determination unit 19 determines the replacement timing of the first ion exchanger 13 based on the cumulative value of the ion concentration estimated from the temperature of the refrigerant obtained by the first temperature acquisition unit 14 and the second temperature acquisition unit 15. Thereby, the replacement timing of the first ion exchanger 13 can be determined with high accuracy.

[0087] Based on at least one of the stop time and the outside gas temperature information, the starting discharge amount of the refrigerant pumped by the first pumping unit 22 at the start of the first fuel cell stack 11 and the second fuel cell stack 12 is determined. And the first pumping unit 22 performs control based on the starting discharge amount prior to the pumping control corresponding to the required output at the start of the first fuel cell stack 11 and the second fuel cell stack 12. Thereby, the deviation of the concentration of the ions contained in the refrigerant can be reduced in the first fuel cell stack 11 and the second fuel cell stack 12. Thereby, the replacement timing of the first ion exchanger 13 can be determined with high accuracy.

[0088] (Other examples)

[0089] Figure 4 It is a schematic diagram showing the fuel cell system 200 in the embodiment.

[0090] In the fuel cell system 200, for the parts that are the same as the components in the fuel cell system 10, the same reference numerals are used and their descriptions are omitted, and only the different points are described.

[0091] In addition to the structure of the fuel cell system 10, the fuel cell system 200 further includes a second ion exchanger 201 and a branch flow path 202. The fuel cell system 200 may also include a second pumping unit 203 and a second valve mechanism 204.

[0092] The second ion exchanger 201 is provided in the branch flow path 202, and is connected to the first fuel cell stack 11 and the second fuel cell stack 12 via the branch flow path 202, the second valve mechanism 204, the first refrigerant flow path 27, and the second refrigerant flow path 28.

[0093] The branch flow path 202 selectively branches the refrigerant through the second valve mechanism 204 in the supply path 21, and returns the refrigerant to the first refrigerant flow path 27 on the upstream side of the first fuel cell stack 11 and the second refrigerant flow path 28 on the upstream side of the second fuel cell stack 12.

[0094] The second refrigerant delivery section 203 is provided in the branch flow path 202, and delivers the refrigerant branched from the supply path 21 to the first refrigerant flow path 27 on the upstream side of the first fuel cell stack 11 and the second refrigerant flow path 28 on the upstream side of the second fuel cell stack 12.

[0095] A method of operating the fuel cell system 200 will be described.

[0096] In the fuel cell system 200, when the first fuel cell stack 11 and the second fuel cell stack 12 are stopped, the FC control device 30 controls the flow time for allowing the refrigerant to flow through the branch flow path 202, at least based on the power generation time. When there is a difference equal to or greater than a specified value between the power generation time of the first fuel cell stack 11 at startup obtained by the first power generation time acquisition unit 16 and the power generation time of the second fuel cell stack 12 at startup obtained by the second power generation time acquisition unit 17, the FC control device 30 circulates the refrigerant between the first fuel cell stack 11 and the second fuel cell stack 12. When there is a difference equal to or greater than a specified value between the stop time of the first fuel cell stack 11 obtained by the first stop time acquisition unit 24 and the stop time of the second fuel cell stack 12 obtained by the second stop time acquisition unit 25, the FC control device 30 circulates the refrigerant between the first fuel cell stack 11 and the second fuel cell stack 12.

[0097] A specific example of the method of operating the fuel cell system 200 will be described.

[0098] Figure 5 This is an example of the system flow of the method of operating the fuel cell system 200.

[0099] At T0 to T1, the first fuel cell stack 11 and the second fuel cell stack 12 are stopped. The first valve mechanism 23 and the second valve mechanism 204 are opened. The first refrigerant delivery section 22 and the second refrigerant delivery section 203 are not started. When the first fuel cell stack 11 and the second fuel cell stack 12 are stopped, the FC control device 30 controls the flow time for allowing the refrigerant to flow through the branch flow path 202, at least based on the power generation time of the first fuel cell stack 11 obtained by the first power generation time acquisition unit 16 and the power generation time of the second fuel cell stack 12 obtained by the second power generation time acquisition unit 17. That is, the second valve mechanism 204 is adjusted to control the flow time for allowing the refrigerant to flow through the branch flow path 202.

[0100] At T1, when the FC control device 30 starts the first fuel cell stack 11 and the second fuel cell stack 12, it controls the flow time for the refrigerant to flow through the branch flow path 202 based at least on the stop time of the first fuel cell stack 11 obtained by the first stop time acquisition unit 24 and the stop time of the second fuel cell stack 12 obtained by the second stop time acquisition unit 25. That is, the second valve mechanism 204 is adjusted to control the flow time for the refrigerant to flow through the branch flow path 202. At T1 to T2, the second valve mechanism 204 is closed, and the second pumping unit 203 is started to pump the refrigerant branched from the supply path 21 to the first refrigerant flow path 27 on the upstream side of the first fuel cell stack 11 and the second refrigerant flow path 28 on the upstream side of the second fuel cell stack 12.

[0101] At T2 to T3, the second valve mechanism 204 is slightly opened, the first pumping unit 22 is started, and the state in which the second pumping unit 203 is started is maintained. The output of the first pumping unit 22 (the output of pumping the refrigerant) is made substantially equal to the output of the second pumping unit 203 (the output of pumping the refrigerant). Thereby, the refrigerant branched from the supply path 21 is pumped to the first refrigerant flow path 27 on the upstream side of the first fuel cell stack 11 and the second refrigerant flow path 28 on the upstream side of the second fuel cell stack 12, and the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 is supplied to the first ion exchanger 13 via the supply path 21.

[0102] At T3 to T4, the second valve mechanism 204 is further opened, and the state in which the first pumping unit 22 and the second pumping unit 203 are started is maintained. The output of the first pumping unit 22 is made larger than the output of the second pumping unit 203. Thereby, the refrigerant discharged from the first fuel cell stack 11 and the second fuel cell stack 12 is supplied only to the first ion exchanger 13 via the supply path 21.

[0103] As described above, in the fuel cell system 200 of the embodiment, when the first fuel cell stack 11 and the second fuel cell stack 12 are started, the flow time for the refrigerant to flow through the branch flow path 202 is controlled based at least on the stop time, whereby the replacement timing of the first ion exchanger 13 and the second ion exchanger 201 can be accurately judged.

[0104] When the first fuel cell stack 11 and the second fuel cell stack 12 are started, the flow time for the refrigerant to flow through the branch flow path 202 is controlled based at least on the stop time, whereby the replacement timing of the first ion exchanger 13 and the second ion exchanger 201 can be accurately judged.

[0105] When the first fuel cell stack 11 and the second fuel cell stack 12 are stopped, the circulation time for causing the refrigerant to flow through the branch flow path 202 is controlled at least based on the power generation time, whereby the replacement timing of the first ion exchanger 13 and the second ion exchanger 201 can be determined with high accuracy.

[0106] When there is a difference greater than or equal to a specified value between the power generation time of the first fuel cell stack 11 at startup obtained by the first power generation time acquisition unit 16 and the power generation time of the second fuel cell stack 12 at startup obtained by the second power generation time acquisition unit 17, the refrigerant is circulated between the first fuel cell stack 11 and the second fuel cell stack 12, whereby the deviation in the concentration of ions contained in the refrigerant can be reduced in the first fuel cell stack 11 and the second fuel cell stack 12. Thereby, the replacement timing of the first ion exchanger 13 and the second ion exchanger 201 can be determined with high accuracy.

[0107] When there is a difference greater than or equal to a specified value between the stop time of the first fuel cell stack 11 obtained by the first stop time acquisition unit 24 and the stop time of the second fuel cell stack 12 obtained by the second stop time acquisition unit 25, the refrigerant is circulated between the first fuel cell stack 11 and the second fuel cell stack 12, whereby the deviation in the concentration of ions contained in the refrigerant can be reduced in the first fuel cell stack 11 and the second fuel cell stack 12. Thereby, the replacement timing of the first ion exchanger 13 and the second ion exchanger 201 can be determined with high accuracy.

[0108] In the above-described embodiment, an example in which the fuel cell system is mounted on a fuel cell vehicle that uses the power generated by the fuel cell as power for traveling or power for operating in-vehicle equipment has been described, but this system can also be mounted on motor vehicles such as two-wheeled, three-wheeled, and four-wheeled vehicles, other moving bodies (e.g., ships, flying bodies, robots), and can also be mounted on a stationary fuel cell system.

[0109] The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and its equivalent scope.

Claims

1. A fuel cell system, wherein, The fuel cell system includes: a plurality of fuel cell stacks; a first ion exchanger that reduces the ion concentration in the refrigerant; a plurality of temperature acquisition units that acquire the temperature of the refrigerant in each of the plurality of refrigerant flow paths on the downstream side of the plurality of fuel cell stacks in the plurality of refrigerant flow paths that supply the refrigerant to the plurality of fuel cell stacks respectively; a power generation time acquisition unit that acquires the power generation time of the plurality of fuel cell stacks; a supply path that supplies the refrigerant discharged from the plurality of fuel cell stacks to the first ion exchanger; an ion concentration estimation unit that estimates the ion concentration of the refrigerant based on at least one of the temperature of each refrigerant acquired by the temperature acquisition unit and the total power generation time of the plurality of fuel cell stacks acquired by the power generation time acquisition unit; a determination unit that determines the replacement timing of the first ion exchanger based on the ion concentration estimated by the ion concentration estimation unit; a pumping unit that supplies the refrigerant according to the required output of the plurality of fuel cell stacks; a plurality of stop time acquisition units that acquire the stop time of each of the plurality of fuel cell stacks; an external gas temperature information acquisition unit that acquires the external gas temperature information during the stop of the fuel cell stack; and a control unit that controls the plurality of fuel cell stacks, the temperature acquisition unit, the power generation time acquisition unit, the ion concentration estimation unit, and the determination unit, the plurality of refrigerant flow paths are arranged in series or in parallel, the control unit determines the starting discharge amount of the refrigerant pumped by the pumping unit at the start of the plurality of fuel cell stacks based on at least one of the stop time and the external gas temperature information, and the pumping unit performs control based on the starting discharge amount prior to the pumping control corresponding to the required output at the start of the plurality of fuel cell stacks.

2. The fuel cell system according to claim 1, wherein, The ion concentration estimation unit estimates that the higher the temperature of the refrigerant in each of the fuel cell stacks acquired by the temperature acquisition unit, the more the amount of ions dissolved from the refrigerant, the determination unit determines the replacement timing of the first ion exchanger according to the cumulative value of the ion concentration estimated from the temperature of each refrigerant acquired by the temperature acquisition unit.

3. The fuel cell system according to claim 1 or 2, wherein, The plurality of refrigerant flow paths that supply the refrigerant to the plurality of fuel cell stacks respectively are arranged in parallel, The fuel cell system includes: a branch flow path that selectively branches the refrigerant in the supply path and returns the refrigerant to the refrigerant flow path on the upstream side of the plurality of fuel cell stacks; and a second ion exchanger provided in the branch flow path, the control unit controls the flow time of the refrigerant flowing through the branch flow path at the start of the plurality of fuel cell stacks based on at least the stop time.

4. The fuel cell system according to claim 1 or 2, wherein, The plurality of refrigerant flow paths that supply the refrigerant to the plurality of fuel cell stacks respectively are arranged in parallel, The fuel cell system includes: a branch flow path that selectively branches the refrigerant in the supply path and returns the refrigerant to the refrigerant flow path on the upstream side of the plurality of fuel cell stacks; and a second ion exchanger provided in the branch flow path, When the plurality of fuel cell stacks stop, the control unit controls the flow time for causing the refrigerant to flow through the branch flow path based at least on the power generation time.

5. The fuel cell system according to claim 3, wherein, The plurality of fuel cell stacks include a first fuel cell stack and a second fuel cell stack. When there is a difference greater than or equal to a specified value between the power generation time of the first fuel cell stack at startup obtained by the power generation time acquisition unit and the power generation time of the second fuel cell stack at startup obtained by the power generation time acquisition unit, the control unit causes the refrigerant to circulate between the first fuel cell stack and the second fuel cell stack.

6. The fuel cell system according to claim 4, wherein, The plurality of fuel cell stacks include a first fuel cell stack and a second fuel cell stack. When there is a difference greater than or equal to a specified value between the stop time of the first fuel cell stack obtained by the stop time acquisition unit and the stop time of the second fuel cell stack obtained by the stop time acquisition unit, the control unit causes the refrigerant to circulate between the first fuel cell stack and the second fuel cell stack.

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