JP2024008693A - fuel cell unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the smoothing capacitor from overheating due to heat generated on the boost converter side.

SOLUTION: A fuel cell unit includes a fuel cell stack having a plurality of cells cooled by a refrigerant, a boost converter that boosts and outputs the output voltage of the fuel cell stack, and a case that accommodates the fuel cell stack and the boost converter in the same space, and the boost converter includes a power module, a smoothing capacitor, and a bus bar that electrically connects the power module and the smoothing capacitor, and a heat conductive member is provided to thermally connect the bus bar and the fuel cell stack.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a fuel cell unit.

Patent Document 1 discloses a fuel cell unit having a structure in which a fuel cell stack including a plurality of cells and a boost converter including a smoothing capacitor are housed in the same case. In this fuel cell unit, a plurality of cells are cooled by cooling water flowing through a cooling water flow path provided inside the fuel cell stack. Therefore, in the fuel cell stack, the cells arranged on the inlet side of the cooling water flow path have a lower temperature than the cells arranged on the exit side of the cooling water flow path. Therefore, in this fuel cell unit, among the parts that make up the boost converter, parts that have a low upper limit of heat resistance and are difficult to cool with water are placed on the inlet side of the cooling water flow path of the fuel cell stack. is configured to suppress

JP2021-128847A

However, the configuration described in Patent Document 1 protects the smoothing capacitor of the boost converter from the heat released into the case by the fuel cell stack, and protects the smoothing capacitor from the heat generated on the boost converter side. It wasn't. Therefore, in the configuration described in Patent Document 1, when the boost converter generates heat, overheating due to the smoothing capacitor receiving heat directly from the bus bar cannot be prevented.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fuel cell unit that can prevent overheating of a smoothing capacitor caused by heat generated on the boost converter side.

The present invention provides a fuel cell stack having a plurality of cells cooled by a refrigerant, a boost converter that boosts and outputs the output voltage of the fuel cell stack, and the fuel cell stack and the boost converter that are housed in the same space. The step-up converter is a fuel cell unit including a power module, a smoothing capacitor, and a bus bar that electrically connects the power module and the smoothing capacitor, and the boost converter is a fuel cell unit that includes a power module, a smoothing capacitor, and a bus bar that electrically connects the power module and the smoothing capacitor. It is characterized by comprising a heat conductive member that thermally connects to the battery stack.

According to this configuration, the heat of the bus bar can be transferred from the heat conductive member to the fuel cell stack. Thereby, it is possible to suppress the heat of the bus bar from being transmitted to the smoothing capacitor, and therefore it is possible to prevent the smoothing capacitor from being overheated due to the heat generated on the boost converter side.

Further, the heat conductive member may include a first insulating part that has insulating properties and comes into contact with the bus bar, and a second insulating part that has insulating properties and comes into contact with the cells.

According to this configuration, since the part that contacts the bus bar and the part that contacts the cell have insulation properties, it is possible to receive heat from the bus bar and transfer heat to the cell while preventing short circuits. .

The heat conductive member may include an intermediate portion that is interposed between the first insulating portion and the second insulating portion and has higher thermal conductivity than the first insulating portion and the second insulating portion. You may.

According to this configuration, since the intermediate portion has better thermal conductivity than the first insulating portion and the second insulating portion, the thermal resistance of the heat conducting member can be reduced.

In the present invention, heat of the bus bar can be transferred from the heat conductive member to the fuel cell stack. Thereby, it is possible to suppress the heat of the bus bar from being transmitted to the smoothing capacitor, and therefore it is possible to prevent the smoothing capacitor from being overheated due to the heat generated on the boost converter side.

FIG. 1 is a diagram schematically showing a vehicle equipped with a fuel cell unit according to an embodiment. FIG. 2 is a diagram schematically showing the configuration of a fuel cell unit. FIG. 3 is a diagram for explaining the positional relationship between the fuel cell stack and the boost converter. FIG. 4 is a diagram showing the upper limit temperature of the parts constituting the fuel cell unit. FIG. 5 is a diagram for explaining the route through which heat is transferred.

EMBODIMENT OF THE INVENTION Hereinafter, with reference to drawings, the fuel cell unit in embodiment of this invention is demonstrated concretely. Note that the present invention is not limited to the embodiments described below.

FIG. 1 is a diagram schematically showing a vehicle equipped with a fuel cell unit according to an embodiment. A fuel cell unit (hereinafter referred to as FC unit) 1 includes a fuel cell stack (hereinafter referred to as FC stack) 2 and a boost converter (hereinafter referred to as FDC) 3. The FC unit 1 is mounted on a vehicle Ve that uses a motor (MG) 4 as a power source.

The vehicle Ve is a fuel cell vehicle (FCEV) that drives a motor 4 using electric power generated by the FC stack 2 and runs using the power output from the motor 4. This vehicle Ve includes an FC unit 1, a motor 4, an inverter (INV) 5, and a battery 6.

The FC unit 1 is a unit in which an FC stack 2 and an FDC 3 are electrically connected. The FC stack 2 includes a plurality of cells 21 (shown in FIG. 3). The FDC 3 is a booster that boosts the power generated by the FC stack 2 and outputs the boosted power. FDC3 is a DC/DC converter for fuel cells.

The motor 4 is a traveling motor, and is a motor/generator that functions as an electric motor and a generator. This motor 4 is constituted by an AC motor. Motor 4 is electrically connected to FC unit 1 and battery 6 via inverter 5 . Therefore, the electric power output from the FC stack 2 is supplied to the motor 4 via the inverter 5, thereby driving the motor 4. Alternatively, the motor 4 is driven by supplying electric power output from the battery 6 to the motor 4 via the inverter 5.

The inverter 5 is a power conversion device that converts DC power into AC power and supplies it to the motor 4. Inverter 5 is electrically connected to motor 4, FC unit 1, and battery 6.

The battery 6 is a DC power source, and is composed of a secondary battery that stores electric power to be supplied to the motor 4. The battery 6 supplies power to the motor 4 when sufficient power cannot be generated in the FC stack 2, and stores the power generated by the motor 4 during regeneration. In this case, the electric power output from the battery 6 is supplied to the motor 4 via the inverter 5, and the electric power generated by the motor 4 is supplied to the battery 6 via the inverter 5. Further, the battery 6 is electrically connected to the FC stack 2.

In the FC stack 2 mounted on the vehicle Ve, the number of cells 21 is reduced in order to realize cost reduction and miniaturization. In this case, by reducing the number of cells 21, the total voltage of the entire FC stack 2 is reduced. Therefore, in order to increase the output voltage of the FC stack 2 to the required voltage, an FDC 3 is required at the output section of the FC stack 2. Further, in order to enable efficient arrangement of the vehicle Ve in a limited space, the FC stack 2 and the FDC 3 are configured as one FC unit 1.

Here, the structure of the FC unit 1 will be explained with reference to FIGS. 2 to 5.

The FC unit 1 has a structure in which an FC stack 2 and an FDC 3 are housed in one case 10, as shown in FIGS. 2 and 3. The case 10 houses the FC stack 2 and the FDC 3 in the same space. No partition wall is provided inside the case 10 to separate the FC stack 2 and the FDC 3.

The case 10 is formed to include an FC stack case 11 that accommodates the FC stack 2 and an FDC case 12 that accommodates the FDC 3. The FC stack case 11 and the FDC case 12 are integrated by bolting or the like. The FC stack case 11 and the FDC case 12 form one internal space without partition walls.

In the case 10, the FC stack 2 and the FDC 3 are arranged at positions facing each other in the vertical direction, and the FC stack 2 is arranged above the FDC 3. As shown in FIG. 3, the FC stack 2 is arranged on the upper side of the case 10, and the FDC 3 is arranged on the lower side of the case 10. The FC stack 2 is housed in a common case 10 with the FDC 3, and is located above the FDC 3 and close to the ceiling surface of the case 10. The FDC 3 is housed in a common case 10 with the FC stack 2, and is located below the FC stack 2 and close to the lower surface of the cell 21. Note that FIG. 3 schematically shows the structure taken along the line AA in FIG. 2.

The FC stack 2 includes a cell stack 22 in which a plurality of cells 21 are stacked, and a pair of terminals 23 and 24.

The cell stack 22 has a structure in which a plurality of cells 21 are stacked in a predetermined direction. In the cell stack 22, electricity and water are generated by a chemical reaction between hydrogen and oxygen in each cell 21. The cell 21 has a structure in which an MEA (Membrane Electrode Assembly) is sandwiched between a pair of separators, a hydrogen flow path is provided on one side of the separators, and an oxygen flow path is provided on the other side. In the cell stack 22, the plurality of cells 21 are cooled by a refrigerant.

Since the FC stack 2 generates a large amount of heat during power generation, a refrigerant is circulated during operation to prevent the cell 21 from exceeding its upper limit temperature. When the FC stack 2 is operated, the temperature is always controlled by a coolant such as cooling water to a temperature that suppresses deterioration of the FC stack 2 and provides excellent power generation efficiency. Specifically, while the FC stack 2 is in operation, heat is generated in the cells 21 due to fuel cell reactions, so each cell 21 is cooled by cooling water flowing inside the FC stack 2 . The cooling water is, for example, a cooling liquid containing ethylene glycol as a main component. A cooling water flow path through which cooling water flows is provided inside the FC stack 2. In this way, since the FC stack 2 is cooled from inside by the cooling water flowing through the cooling water flow path, the temperature rise of the cells 21 is suppressed.

The pair of terminals 23 and 24 are terminals for taking out the electric power generated by the fuel cell reaction of each cell 21, and are provided at both ends of the cell stack 22 in the stacking direction. The pair of terminals 23 and 24 includes a P terminal 23 and an N terminal 24.

The P terminal 23 is disposed on one side of the cell stack 22 in the stacking direction, and has a protrusion 23a that protrudes from the cell stack 22 toward the FDC 3 side. The protrusion 23a of the P terminal 23 is the positive terminal of the FC stack 2. The N terminal 24 is disposed on the other side of the cell stack 22 in the stacking direction, and has a protrusion 24a that protrudes from the cell stack 22 toward the FDC 3 side. The protrusion 24a of the N terminal 24 is the negative terminal of the FC stack 2.

The P terminal 23 electrically connects the positive electrode side of the FC stack 2 and the positive electrode bus bar (P bus bar) 41 upstream of the reactor 31 of the FDC 3 . The protrusion 23a of the P terminal 23 and the positive bus bar 41 are connected by bolts or the like. The N terminal 24 electrically connects the negative electrode side of the FC stack 2 and the negative electrode bus bar (N bus bar) 42 downstream of the smoothing capacitor 34 of the FDC 3 . The protrusion 24a of the N terminal 24 and the negative bus bar 42 are connected by bolts or the like. In one internal space within the case 10, the FC stack 2 and the FDC 3 are directly connected by a positive bus bar 41 and a negative bus bar 42.

The FDC 3 includes a reactor 31, a current sensor 32, a power module (hereinafter referred to as IPM) 33, a smoothing capacitor 34, a branch box, and a terminal block 35.

The reactor 31 is provided between the P terminal 23 and the IPM 33. FDC3 is a multiphase boost converter and includes four reactors 31A to 31D.

The four reactors 31A to 31D are connected in parallel between the P terminal 23 and the IPM 33. Each of the reactors 31A to 31D is connected in parallel to the P terminal 23 using a bus bar, and is also connected in parallel to the IPM 33 using a bus bar. A current sensor 32 is attached to a bus bar connecting each of the reactors 31A to 31D and the IPM 33.

Current sensor 32 measures the value of the current flowing between reactor 31 and IPM 33. For example, the current sensor 32 is configured by a Hall element type current sensor including a magnetic core through which a bus bar passes, and a Hall element inserted into a gap between the magnetic cores.

The IPM 33 is an intelligence power module including a switching element and a diode. The switching element of the IPM 33 performs a switching operation so as to cause the reactor 31 to periodically repeat accumulation and release of power in accordance with switching control by the control device when the voltage from the FC stack 2 is input. The power released from the reactor 31 is output to the smoothing capacitor 34 via the diode of the IPM 33. A bus bar 50 is connected to the output side of the IPM 33.

The bus bar 50 is a bus bar that electrically connects the IPM 33 and the smoothing capacitor 34. The bus bar 50 includes a P bus bar 51 and an N bus bar 52. P bus bar 51 and N bus bar 52 are each connected to an element (capacitor element) of smoothing capacitor 34. That is, the bus bar 50 is a capacitor bus bar. In addition, in this description, when the P bus bar 51 and the N bus bar 52 are not distinguished, they will be referred to as the bus bar 50.

The smoothing capacitor 34 is a capacitor that smoothes the voltage output from the IPM 33. This smoothing capacitor 34 includes a capacitor element. For example, the capacitor element is a plastic film (dielectric film) of a film capacitor.

Further, the smoothing capacitor 34 is electrically connected to the branch box and the terminal block 35 via a bus bar. The N terminal 24 is connected to the smoothing capacitor 34 via a branch box and a terminal block 35.

The branch box and the terminal block 35 are components arranged downstream of the smoothing capacitor 34. The branch box and terminal block 35 are electrically connected to the N terminal 24 via a negative bus bar 42 . A battery output terminal 61 provided on the outside of the case 10, a PCU output terminal 62, and an air compressor inverter output terminal 63 are connected to the branch box and the terminal block 35.

Further, the FDC 3 includes a reactor cooler 71 and an IPM control board 72.

The reactor cooler 71 is a cooler attached to the lower part of the case 10, and cools the reactor 31 with cooling water flowing inside. The reactor 31 is water-cooled. The reactor cooler 71 is connected to a cooling circuit in which cooling water cooled by a radiator circulates. The reactor cooler 71 is attached to the lower part of the FDC case 12.

The reactors 31A to 31D are attached to the bottom surface of the case 10 corresponding to the position where the reactor cooler 71 is attached. Cooling water supplied to the reactor cooler 71 circulates through the cooling circuit. For example, this cooling circuit includes a pump, a radiator, and a reactor cooler 71. Cooling water that is pumped under pressure and circulated within the cooling circuit is cooled by a radiator and then supplied to the reactor cooler 71.

The IPM control board 72 is a board that controls the switching elements of the IPM 33. The IPM control board 72 is arranged below the IPM 33. The IPM control board 72 is housed in a separate room provided below the outside of the case 10, unlike other components. A cover 13 that houses the IPM control board 72 is attached to the lower part of the case 10. The cover 13 is attached to the lower part of the FDC case 12 by bolting or the like and is integrated with the case 10.

In the FC unit 1 configured in this manner, the smoothing capacitor 34 is a component with a particularly low heat resistance among the components of the FDC 3. As shown in FIG. 4, the heat-resistant temperature of the components of the FDC 3 varies depending on the component, but the heat-resistant temperature of the element of the smoothing capacitor 34 is about 105 to 120 degrees Celsius, which is particularly low compared to other components. . While the FC stack 2 is in operation, the temperature of the cell 21 is about 100°C, and the surface temperature of the FC stack 2 is about 95 to 105°C. In this way, the upper limit temperature of the elements of the smoothing capacitor 34 is higher than the temperature of the FC stack 2 . In the FC unit 1, each of the FC stack 2 and the FDC 3 is subject to cooling with cooling water, and although the reactor 31 can be cooled with cooling water, it is difficult to cool the smoothing capacitor 34 with water. Therefore, the FC unit 1 is configured to protect the smoothing capacitor 34 from heat.

The temperature of the smoothing capacitor 34 increases due to two factors: heat generation of the capacitor element itself and heat transfer from the P bus bar 51 and the N bus bar 52 connected to the capacitor element.

Regarding heat generation of the capacitor element itself, which is the first factor, the structure is such that the heat of the smoothing capacitor 34 is transferred from the heat dissipation sheet 73 to the case 10. The heat from the smoothing capacitor 34 is transmitted through the heat dissipation sheet 73 and the case 10 in this order.

The heat dissipation sheet 73 is interposed between the smoothing capacitor 34 and the FDC case 12. For example, a heat dissipation sheet 73 is sandwiched between the bottom of the smoothing capacitor 34 and the bottom of the FDC case 12. The heat dissipation sheet 73 is made of an insulating heat conductive member such as a silicon-based heat conductive member.

When the capacitor element itself of the smoothing capacitor 34 generates heat, the heat of the smoothing capacitor 34 is transferred to the FDC case 12 via the heat dissipation sheet 73, as shown in FIG. In this way, the heat of the capacitor element can be released from the heat dissipation sheet 73 to the FDC case 12. As a result, the heat generated in the capacitor element of the smoothing capacitor 34 is transmitted from the heat radiation sheet 73 to the FDC case 12, and is radiated from the FDC case 12 to the outside of the case 10. Note that FIG. 5 schematically shows a structure in which the portion surrounded by the broken line in FIG. 3 is enlarged.

Regarding heat transfer from the P bus bar 51 and the N bus bar 52, which is the second factor, the configuration is such that the heat of the bus bar 50 is transferred from the heat conductive member 80 to the FC stack 2. A heat conductive member 80 is provided inside the case 10 as a member for suppressing heat from the bus bar 50 from being transmitted to the smoothing capacitor 34 . In the smoothing capacitor 34, heat transfer from the P bus bar 51 and the N bus bar 52 is suppressed, thereby suppressing a rise in temperature of the capacitor element.

The heat conductive member 80 is a member that thermally connects the bus bar 50 and the FC stack 2. The heat conductive member 80 is interposed between the bus bar 50 and the FC stack 2. That is, the bus bar 50 connected to the element of the smoothing capacitor 34 and the FC stack 2 are connected by the thermally conductive member 80 made of an insulating member with excellent thermal conductivity. Inside the case 10, a heat transfer path for dissipating the heat of the bus bar 50 to the FC stack 2 is formed by the heat conductive member 80. The heat from the bus bar 50 is transferred through the heat conductive member 80 and then the FC stack 2 in that order.

The heat conductive member 80 has a first insulating section 81 , an intermediate section 82 , and a second insulating section 83 . This heat conductive member 80 has a three-layer structure.

The first insulating portion 81 is a portion that has insulating properties and contacts the bus bar 50 . This first insulating section 81 forms the first layer of a three-layer structure. The first insulating section 81 is made of, for example, a silicon-based heat conductive member such as a cercon sheet or a gap filler. This first insulating portion 81 makes surface contact with the surface of the bus bar 50 .

The intermediate portion 82 is a portion that is interposed between the first insulating portion 81 and the second insulating portion 83 and has better thermal conductivity than the first insulating portion 81 and the second insulating portion 83. This intermediate portion 82 forms the second layer of the three-layer structure. Since the intermediate portion 82 does not require insulation, it is made of a metal with excellent thermal conductivity such as copper or aluminum.

The second insulating part 83 is a part that has insulating properties and comes into contact with the cell 21 . This second insulating portion 83 forms the third layer of a three-layer structure. The second insulating portion 83 is made of a silicon-based heat conductive member such as a cercon sheet or a gap filler. This second insulating portion 83 is in surface contact with the surface of the FC stack 2 . Specifically, the second insulating portion 83 makes surface contact with the surface of the cell 21 . In this case, the second insulating section 83 can be configured to make surface contact with the lower surfaces of the plurality of cells 21. That is, the second insulating portion 83 is configured to be in surface contact with the lower surface of the cell stack 22 .

When the heat of the bus bar 50 is transferred to the cell 21 via the heat conducting member 50, the first insulating portion 81 of the heat conducting member 80 receives the heat from the bus bar 50, and the heat is transferred from the first insulating portion 81 via the intermediate portion 82. and is transmitted to the second insulating section 83 and delivered from the second insulating section 83 to the cell 21. In the FC stack 2, since each cell 21 is cooled by cooling water, the temperature rise of the cell 21 is suppressed. Furthermore, since the FC stack 2 includes the cell stack 22, it has a large heat capacity. Therefore, the heat of the bus bar 50 can be radiated (transferred) from the heat conductive member 80 to the cells 21 of the FC stack 2 .

The heat conductive member 80 configured in this manner is provided on both the P bus bar 51 and the N bus bar 52. For example, the heat conductive member 80 includes two heat conductive members, a first heat conductive member interposed between the P bus bar 51 and the cell 21, and a second heat conductive member interposed between the N bus bar 52 and the cell 21. Contains parts. In this case, the first insulating portion 81 of the first heat conductive member is in surface contact with the surface of the P bus bar 51. The first insulating portion 81 of the second heat conductive member is in surface contact with the surface of the N bus bar 52 . Then, the heat of the P bus bar 51 is transferred to the cell 21 via the first heat conductive member. The heat of the N bus bar 52 is transferred to the cell 21 via the second heat conductive member.

Under conditions where the bus bar 50 becomes highly heated, the heat of the bus bar 50 is transferred to the FC stack 2 via the heat conductive member 80, as shown in FIG. In this way, the heat of the bus bar 50 can be released from the heat conductive member 80 to the FC stack 2. As a result, it is possible to prevent heat from flowing into the smoothing capacitor 34 from the bus bar 50.

Generally, the upper limit temperature of the elements of the smoothing capacitor 53 is about 120°C. On the other hand, since the cell 21 of the FC stack 2 is cooled by cooling water, its temperature (cell temperature) is about 100°C. Under conditions where the temperature of the bus bar 50 exceeds the upper limit of heat resistance temperature of the capacitor element of the smoothing capacitor 34, the heat of the bus bar 50 flows from the heat conductive member 80 to the FC stack 2 side, thereby suppressing the flow of heat from the bus bar 50 to the capacitor element. can do. Thereby, heat from the bus bar 50 can be released to the FC stack 2, and heat can be prevented from flowing into the smoothing capacitor 34.

As explained above, according to the embodiment, in the FC unit 1 having a structure in which the FC stack 2 and the FDC 3 are integrated, the bus bar 50 and the FC stack 2 are connected to the thermally conductive member 80 in the case 10 that accommodates them. Thermal connection is made by When the FC stack 2 is in operation, the temperature of the cell 21 is lower than the upper limit temperature of the elements of the smoothing capacitor 34. Therefore, under conditions where the temperature of the bus bar 50 exceeds the upper limit temperature of the capacitor element, the heat of the bus bar 50 is transferred to the FC stack 2. Since the heat flows to the side, it is possible to suppress the flow of heat into the capacitor element. Thereby, it is possible to suppress the elements of the smoothing capacitor 34 from directly receiving heat from the bus bar 50, and it is possible to prevent the smoothing capacitor 34 from overheating due to the heat generated on the FDC 3 side.

Moreover, although the structure in which the FDC 3 is arranged below the FC stack 2 has been described, the present invention is not limited to this. The FDC 3 may be placed above, below, left, or right of the FC stack 2. As an example of a modification, in the case of a structure in which the FDC 3 is arranged above the FC stack 2, the arrangement in FIG. 3 is reversed vertically (the arrangement in FIG. 3 is rotated 180 degrees clockwise on the paper). Is possible. Alternatively, in the case of a structure in which the FDC 3 is arranged on the left side of the FC stack 2, it is possible to rotate the arrangement in FIG. 3 clockwise by 90 degrees on the paper. Alternatively, in the case of a structure in which the FDC 3 is arranged on the right side of the FC stack 2, it is possible to rotate the arrangement in FIG. 3 by 90 degrees counterclockwise on the paper.

Further, the heat conductive member 80 is not limited to the three-layer structure consisting of the first insulating part 81, the intermediate part 82, and the second insulating part 83. The heat conductive member 80 may be entirely composed of an insulating member having insulation properties. That is, the heat conductive member 80 may have a single layer structure made of a member having excellent heat conductivity and insulation properties. Comparing the thermal conductivity of the thermal conductive member 80 with the three-layer structure and the thermal conductive member 80 with the single-layer structure, the three-layer structure has better thermal conductivity because the thermal resistance is smaller due to the intermediate portion 82. There is.

Further, the heat conduction member 80 is not limited to a configuration in which one heat conduction member 80 is provided for each of the P bus bar 51 and the N bus bar 52 (a configuration including a first heat conduction member and a second heat conduction member). The number of heat conductive members 80 is not limited. For example, a configuration may be adopted in which one heat conductive member 80 makes surface contact with the P bus bar 51 and the N bus bar 52.

Further, a boost converter (BDC) may be provided between the battery 6 and the inverter 5 in the power supply circuit mounted on the vehicle Ve.

1 Fuel cell unit (FC unit)
2 Fuel cell stack (FC stack)
3 Boost converter (FDC)
4 Motor 5 Inverter 6 Battery 10 Case 11 FC stack case 12 FDC case 21 Cell 22 Cell stack 23 P terminal 23a Projection 24 N terminal 24a Projection 31, 31A, 31B, 31C, 31D Reactor 32 Current sensor 33 Power module ( IPM)
34 Smoothing capacitor 35 Branch box and terminal block 41 Positive bus bar 42 Negative bus bar 50 Bus bar 51 P bus bar 52 N bus bar 80 Heat conductive member 81 First insulating part 82 Intermediate part 83 Second insulating part

Claims (3)

a fuel cell stack having a plurality of cells cooled by a refrigerant;
a boost converter that boosts and outputs the output voltage of the fuel cell stack;
a case that accommodates the fuel cell stack and the boost converter in the same space;
Equipped with
The boost converter is a fuel cell unit including a power module, a smoothing capacitor, and a bus bar electrically connecting the power module and the smoothing capacitor,
A fuel cell unit comprising: a heat conductive member that thermally connects the bus bar and the fuel cell stack. The thermally conductive member is
a first insulating part that has insulating properties and contacts the bus bar;
The fuel cell unit according to claim 1, further comprising a second insulating part that has an insulating property and contacts the cell. The thermally conductive member has an intermediate portion that is interposed between the first insulating portion and the second insulating portion and has higher thermal conductivity than the first insulating portion and the second insulating portion. The fuel cell unit according to claim 2.

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