KR102691017B1 - Fuel cell Vehicle and method for discharging remaining energy and performed in the vehicle - Google Patents

Abstract

The fuel cell vehicle of the embodiment includes a cell stack in which a plurality of unit cells are stacked, a discharge unit that discharges the residual voltage output from both output terminals of the cell stack in response to a discharge control signal, and the discharge unit itself discharges the residual voltage. It includes a discharge auxiliary unit that forms a bypass path that can discharge the residual voltage in the discharge unit when this cannot be done, and a main control unit that generates a discharge control signal when it is necessary to discharge the residual voltage.

Description

Fuel cell vehicle and method for discharging remaining energy and performed in the vehicle}

Embodiments relate to fuel cell vehicles and methods of discharging residual energy performed in the vehicle.

In a vehicle having a fuel cell including a cell stack (hereinafter referred to as a ‘fuel cell vehicle’), there is a need to improve the durability of the cell stack by removing oxygen in the air channels of the cell stack after the vehicle’s engine is turned off. Alternatively, in the event of a fuel cell vehicle crash, it is necessary to remove the electrical energy remaining in the cell stack to prevent secondary electric shock or electrical fire. Alternatively, to prevent electric shock accidents during vehicle maintenance after the fuel cell vehicle's engine is turned off, it is necessary to remove the electrical energy remaining in the cell stack.

In this way, it is very important to ensure the electrical safety of the fuel cell vehicle by removing the electrical energy remaining in the cell stack when the engine of the fuel cell vehicle is turned off, the vehicle crashes, or maintenance work is performed.

Embodiments provide a fuel cell vehicle that can stably remove voltage remaining in a cell stack by discharging it when the vehicle's engine is turned off or the vehicle crashes, and a method of discharging residual energy performed in the vehicle.

A fuel cell vehicle according to one embodiment includes a cell stack in which a plurality of unit cells are stacked; a discharge unit that discharges residual voltage output from both output terminals of the cell stack in response to a discharge control signal; a discharge auxiliary unit that forms a bypass path through which the residual voltage can be discharged in the discharge unit when the residual voltage cannot be discharged in the discharge unit itself; and a main control unit that generates the discharge control signal when it is necessary to discharge the residual voltage.

For example, the discharge unit may include a sub-control unit that generates at least one driving signal in response to the discharge control signal; a heat dissipation resistance stage including at least one resistor on one side of which is connected to a first output terminal connected to a high potential level of the residual voltage among the two output terminals of the cell stack; and at least one first connected between the other side of the at least one resistor and a second output terminal connected to a low potential level of the residual voltage among the two output terminals of the cell stack, and switching in response to the at least one driving signal. It may include a switching element.

For example, the at least one driving signal includes first to Mth driving signals (where M is a positive integer of 2 or more), the at least one resistor is connected in parallel with each other, and each is connected to the first output terminal. Includes first to Mth resistors having one side connected to, wherein the at least one first switching element switches in response to the first to Mth driving signals, and the other side of the first to Mth resistors and It may include 1-1st to 1-M switching elements respectively connected between the second output terminals.

For example, each of the first to Mth resistors may include a sheath heater, a ceramic heater, an electrical resistance element, or a positive temperature coefficient (PTC) resistor.

For example, the at least one first switching element may include a semiconductor switch.

For example, the semiconductor switch may include IGBT, Silicon Controlled Rectifiers (SCR), Gate Turn Off Thyristors (GTO), Bipolar Junction Transistor (BJT), or Metal Oxide Semiconductor Field Effect Transistors (MOSFET).

For example, the discharge unit may include a COD heater.

For example, the discharge auxiliary unit may include a second switching element that is turned on when the discharge unit itself cannot discharge the residual voltage; and a connection portion connecting the other side of the at least one resistor to the second output terminal of the cell stack when the second switching element is turned on.

For example, the second switching element is a normally closed type that is turned off in response to the first switching control signal and turned on when the first switching control signal is not generated, and the main control unit receives the discharge control signal. The first switching control signal can be generated when is generated.

For example, the fuel cell vehicle further includes a switching unit that provides the stack voltage output from both output terminals of the cell stack to a load in response to a second switching control signal, and the main control unit controls the residual voltage. The second switching control signal may be generated in response to a result of checking whether discharge is necessary.

For example, when an operating voltage is applied, the main controller determines whether it is necessary to discharge the residual voltage, and selects at least one of the discharge control signal, the first switching control signal, and the second switching control signal. You can create one.

For example, the fuel cell vehicle further includes a start-up inspection unit that checks whether the engine of the fuel cell vehicle has stopped, and the main control unit responds to a result inspected by the start-up test unit by sending the discharge control signal, the first At least one of a 1 switching control signal or the second switching control signal may be generated.

For example, the fuel cell vehicle further includes a collision inspection unit that checks whether the fuel cell vehicle has collided, and the main control unit controls the discharge control signal and the first switching in response to a result inspected by the collision inspection unit. At least one of a control signal or the second switching control signal may be generated.

According to another embodiment, a residual energy discharging method performed in a fuel cell vehicle including a fuel cell including a cell stack in which a plurality of unit cells are stacked and a discharge unit discharging residual voltage of the cell stack includes: checking whether there is a need to discharge residual voltage; When it is necessary to discharge the residual voltage of the cell stack, checking whether the residual voltage can be discharged in the discharge unit itself; discharging the residual voltage in the discharge unit itself when the residual voltage can be discharged in the discharge unit itself; and when the residual voltage cannot be discharged in the discharge unit itself, discharging the residual voltage in the discharge unit through a bypass path.

For example, the step of checking whether it is necessary to discharge the residual voltage includes checking whether the fuel cell vehicle has stopped starting; Or it may include at least one of the steps of checking whether the fuel cell vehicle has crashed, and when the engine of the fuel cell vehicle stops or the fuel cell vehicle has crashed, it may be determined that the residual voltage needs to be discharged. .

The fuel cell vehicle according to the embodiment and the residual energy discharging method performed in this vehicle use the discharge auxiliary unit to discharge the remaining voltage of the cell stack even when the residual voltage of the cell stack must be discharged and the residual voltage cannot be discharged from the discharge unit itself. Since the voltage can be discharged, the residual energy discharge function of the cell stack is guaranteed and electrical stability is ensured, resulting in high reliability.

1 is a block diagram of a fuel cell vehicle according to an embodiment.
FIG. 2 shows an exemplary cross-sectional view of a fuel cell that may be included in the fuel cell vehicle shown in FIG. 1.
FIG. 3 is a flow chart for explaining a method of discharging residual energy according to an embodiment performed in the vehicle shown in FIG. 1.

Hereinafter, the present invention will be described in detail by way of example embodiments, and will be described in detail with reference to the accompanying drawings to aid understanding of the invention. However, the embodiments according to the present invention may be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described in detail below. Embodiments of the present invention are provided to more completely explain the present invention to those with average knowledge in the art.

In the description of this embodiment, in the case where it is described as being formed "on or under" of each element, it is indicated as being formed "on or under" ( “on or under” includes both elements that are in direct contact with each other or one or more other elements that are formed (indirectly) between the two elements.

Additionally, when expressed as “above” or “on or under,” it can include not only the upward direction but also the downward direction based on one element.

In addition, relational terms such as “first” and “second,” “top/upper/top” and “bottom/bottom/bottom” used below refer to any physical or logical relationship or relationship between such entities or elements. It may be used to distinguish one entity or element from another entity or element, without necessarily requiring or implying order.

Hereinafter, a vehicle having a fuel cell according to an embodiment (hereinafter referred to as a ‘fuel cell vehicle’ or ‘vehicle’) will be described with reference to the attached drawings.

Figure 1 is a block diagram of a fuel cell vehicle 300 according to an embodiment.

Referring to FIG. 1 , a vehicle 300 according to an embodiment may include a cell stack 310, a discharge unit 320, a discharge auxiliary unit 330, and a main control unit 370. Additionally, the vehicle 300 may further include a load 360. Additionally, the vehicle 300 may further include at least one of a start-up inspection unit 380 or a collision inspection unit 350.

First, an example of a fuel cell that may be included in the vehicle 300 will be described as follows with reference to the attached FIG. 2, but the embodiment is not limited to a specific type of fuel cell included in the vehicle 300.

For example, the fuel cell may be a polymer electrolyte membrane fuel cell (PEMFC: Proton Exchange Membrane Fuel Cell), which is the most widely studied as a power source for driving vehicles.

FIG. 2 shows an example cross-sectional view of a fuel cell that may be included in the fuel cell vehicle 300 shown in FIG. 1 .

Referring to FIG. 2, the fuel cell may include first and second end plates (or pressure plates or compression plates) 110A, 110B, a current collector plate 112, and a cell stack 122. there is. The cell stack 122 shown in FIG. 2 may correspond to an example of the cell stack 310 shown in FIG. 1 .

The cell stack 122 may include a plurality of unit cells 122-1 to 122-N stacked in a first direction (eg, x-axis direction). Here, N is a positive integer of 1 or more and may be tens to hundreds. N may be, for example, 100 to 300, preferably 220, but embodiments are not limited to a specific number of N.

Each unit cell 122-n can generate electricity of 0.6 volts to 1.0 volts, on average 0.7 volts. Here, 1≤n≤N. Accordingly, N can be determined depending on the voltage output from the fuel cell and supplied to the load 360 (hereinafter referred to as ‘stack voltage’), that is, the intensity of power.

The load 360 shown in FIG. 1 is a part of the vehicle 300 that requires power corresponding to the stack voltage, including a battery (e.g., high-voltage battery), inverter, motor, and direct current/direct current that boosts the stack voltage. It may refer to parts necessary for driving a vehicle, such as a converter, motor driven power steering (MDPS), radiator fan, and headlight, and the embodiment is not limited to a specific type of load 360.

Additionally, the stack voltage may be output from both output terminals (OUT1 and OUT2) of the cell stack 310. One of the two output terminals (OUT1, OUT2) of the cell stack 310 (OUT1) is connected to the high potential level of the stack voltage, and the other one (OUT2) of the two output terminals (OUT1, OUT2) is connected to the low potential level of the stack voltage. can be connected

Each unit cell 122-n includes a membrane electrode assembly (MEA) 210, a gas diffusion layer (GDL) 222, 224, a gasket 232, 234, 236, and It may include a separation plate (or, bipolar plate or separator) 242, 244.

The membrane electrode assembly 210 has a structure in which a catalyst electrode layer in which an electrochemical reaction occurs is attached to both sides of the electrolyte membrane through which hydrogen ions move. Specifically, the membrane electrode assembly 210 includes a polymer electrolyte membrane (or proton exchange membrane) 212, a fuel electrode (or hydrogen electrode or oxidation electrode) 214, and an air electrode (or oxygen electrode or reduction electrode). It may include (216). Additionally, the membrane electrode assembly 210 may further include a sub gasket 238.

The polymer electrolyte membrane 210 is disposed between the anode 214 and the air electrode 216.

In a fuel cell, hydrogen, which is a fuel, can be supplied to the anode 214 through the first separator plate 242, and air containing oxygen, which is an oxidizing agent, can be supplied to the air electrode 216 through the second separator plate 244. .

Hydrogen supplied to the anode 214 is decomposed into hydrogen ions (protons, H+) and electrons (electrons, e-) by a catalyst, and only hydrogen ions selectively pass through the polymer electrolyte membrane 212 to form the air electrode ( 216), and at the same time, electrons may be transferred to the air electrode 216 through the gas diffusion layers 222 and 224, which are conductors, and the first and second separation plates 242 and 244. For the above-described operation, a catalyst layer may be applied to each of the fuel electrode 214 and the air electrode 216. In this way, the flow of electrons through the external conductor occurs due to the movement of electrons, thereby generating current. It can be seen that a fuel cell generates power through an electrochemical reaction between hydrogen, which is a fuel, and oxygen contained in air.

At the air electrode 216, hydrogen ions supplied through the polymer electrolyte membrane 210 and electrons transferred through the first and second separators 242 and 244 meet oxygen in the air supplied to the air electrode 216 and produce water ( Hereinafter referred to as 'produced water' or 'condensed water'), a reaction occurs. Product water generated in the air electrode 216 may pass through the polymer electrolyte membrane 212 and be delivered to the anode 214.

In some cases, the fuel electrode 214 may be called an anode and the air electrode 216 may be called a cathode, or conversely, the fuel electrode 214 may be called a cathode and the air electrode 216 may be called an anode.

The first and second gas diffusion layers 222 and 224 serve to evenly distribute hydrogen and oxygen, which are reaction gases, and transfer the generated electrical energy. To this end, the first and second gas diffusion layers 222 and 224 may be disposed on both sides of the membrane electrode assembly 210, respectively. The first gas diffusion layer 222 serves to diffuse and evenly distribute hydrogen, a reaction gas supplied through the first separator 242, and may have electrical conductivity. The second gas diffusion layer 224 serves to diffuse and evenly distribute air, which is a reaction gas supplied through the second separator plate 244, and may have electrical conductivity.

The gaskets 232, 234, and 236 maintain airtightness of the reaction gases and coolant and an appropriate clamping pressure, distribute stress when stacking the first and second separator plates 242, 244, and independently seal the flow path. Perform the role instructed. In this way, airtightness/watertightness is maintained by the gaskets 232, 234, and 236, and the flatness of the surface adjacent to the cell stack 122 that generates power is managed, creating a uniform surface pressure on the reaction surface of the cell stack 122. Distribution can be achieved.

The first and second separation plates 242 and 244 may serve to move reaction gases and a cooling medium and to separate each unit cell from other unit cells. In addition, the first and second separator plates 242 and 244 structurally support the membrane electrode assembly 210 and the gas diffusion layers 222 and 224, and serve to collect the generated current and transfer it to the current collector plate 112. It can also be done.

The first and second separation plates 242 and 244 may be spaced apart from each other in a first direction (eg, x-axis direction) and disposed outside the first and second gas diffusion layers 222 and 224, respectively. That is, the first separator plate 242 may be disposed on the left side of the first gas diffusion layer 222, and the second separator plate 244 may be disposed on the right side of the second gas diffusion layer 224.

The first separator 242 serves to supply hydrogen, a reaction gas, to the anode 214 through the first gas diffusion layer 222. The second separation plate 244 serves to supply air, which is a reaction gas, to the air electrode 216 through the second gas diffusion layer 224. In addition, each of the first and second separation plates 242 and 244 may form a channel through which a cooling medium (eg, coolant) can flow.

Meanwhile, the first and second end plates 110A and 110B are disposed on both ends of the cell stack 122 to support and secure a plurality of unit cells. That is, the first end plate 110A may be placed on one of both ends of the cell stack 122, and the second end plate 110B may be placed on the other end of the two ends of the cell stack 122.

The first and second end plates 110A and 110B may have a metal insert surrounded by an injection-molded plastic product. The metal inserts of the first and second end plates 110A and 110B may have high rigidity characteristics to withstand internal surface pressure and may be implemented by machining a metal material.

The current collector plate 112 may be disposed between the cell stack 122 and the inner surfaces 110AI and 110BI of the first and second end plates 110A and 110B facing the cell stack 122 . The current collector 112 collects electrical energy generated by the flow of electrons in the cell stack 122 and supplies it to the load of the vehicle 300A in which the fuel cell is used.

Hereinafter, the configuration of the vehicle 300 for performing a method of discharging the residual energy (eg, residual voltage) of the cell stack 310 will be described as follows.

Referring to FIG. 1, the discharge unit 320 discharges the residual voltage output from both output terminals (OUT1 and OUT2) of the cell stack 310 in response to the discharge control signal (DCS) output from the main control unit 370. do. Hereinafter, among both output terminals (OUT1, OUT2) of the cell stack 310, the output terminal connected to the high potential level of the residual voltage is referred to as the 'first output terminal' (OUT1), and the output terminal (OUT1, OUT2) of the cell stack 310 is referred to as the 'first output terminal' (OUT1). Among them, the output terminal connected to the low potential level of the residual voltage is called the 'second output terminal' (OUT2).

For the above-described operation, the discharge unit 320 may include a sub-controller 322, at least one first switching element (or first relay element), and a heat dissipation resistor stage 324.

The sub-controller 322 generates at least one driving signal in response to the discharge control signal (DCS) output from the main control unit 370, and outputs the generated at least one driving signal to at least one first switching element. .

The heat dissipation resistance stage 324 includes at least one resistor. One side of at least one resistor may be connected to the first output terminal (OUT1).

At least one first switching element may be connected between the other side of at least one resistor and the second output terminal OUT2 of the cell stack 310. At least one switching element may switch in response to at least one driving signal.

According to an embodiment, at least one driving signal output from the sub-controller 322 may include first to Mth driving signals. Here, M may be a positive integer of 2 or more. In this case, at least one resistor includes first to M resistors (R1 to RM) connected in parallel with each other, and at least one first switching element includes 1-1 to 1-M switching elements (S11 to S1M). may include.

One side of each (Rm) of the first to M resistors (R1 to RM) may be connected to the first output terminal (OUT1) of the cell stack 310. Here, 1≤m≤M. According to an embodiment, each of the first to M resistors (R1 to RM) (Rm) may include a sheath heater, a ceramic heater, an electric resistance element, or a Positive Temperature Coefficient (PTC) resistor. The M resistance (R1 to RM) is not limited to a specific type of each (Rm).

In addition, the 1-1st to 1-Mth switching elements (S11 to S1M) each switch in response to the 1st to Mth driving signals, and the other side of the 1st to Mth resistors (R1 to RM) and the second output terminal (OUT2) can be connected respectively. That is, the 1-m switching element (S1m) switches in response to the m-th driving signal and may be connected between the other side of the m-th resistor (Rm) and the second output terminal (OUT2). At least one first switching element may include a semiconductor switch, but embodiments are not limited to a specific type of the first switching element. For example, semiconductor switches include three-terminal IGBTs (Insulated Gate Bipolar mode Transistors), SCRs (Silicon Controlled Rectifiers), GTOs (Gate Turn Off Thyristors), BJTs (Bipolar Junction Transistors), or MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). ), etc. may be included.

For example, when the 1-m switching element (S1m) is implemented as an IGBT, the gate terminal (G) of the IGBT (S1m) is connected to the m-th driving signal, and the collector of the IGBT (S1m) ) terminal (C) may be connected to the other side of the mth resistance (Rm), and the emitter terminal (E) of the IGBT (S1m) may be connected to the second output terminal (OUT2).

According to an embodiment, the discharge unit 320 may include a cathode oxygen depletion (COD) heater. That is, the discharge unit 320 may function as a COD heater. As the discharge unit 320, the resistance heating element of the COD heater is used as a discharge resistor to discharge and consume the electrical energy remaining in the cell stack 310, thereby reducing the residual voltage of the cell stack 310 below a certain level. You can. For example, in the case of the vehicle 300 according to the embodiment, the electrical energy remaining in the cell stack 310 can be reduced to less than 60V DC and 30V AC within 60 seconds after the collision of the vehicle 300.

The COD heater is used to consume residual oxygen present in the air channel during startup (S/U: Start Up) and shutdown (S/D: Shutdown) of the cell stack 310 in order to increase the durability of the fuel cell. It is a resistance heating element. The COD heater consumes the remaining oxygen in the cell stack 310 when the vehicle 300 is in normal operation, that is, discharges the residual voltage, and discharges the remaining voltage in the cell stack 130 when the vehicle 300 crashes. It can play the role of discharging voltage.

In addition, the COD heater, which serves as the discharge unit 320, consumes electricity generated by the motor (not shown) by inertia, serves as a braking resistor to prevent overcharging of the high-voltage battery, and serves as a heating element. By heating the coolant, the temperature of the cell stack 310 in the fuel cell is raised, that is, warmed up to normalize the output performance of the fuel cell, and the cell stack 310 can be heated through its own reaction heat. It can also perform additional functions, such as serving as a load.

Meanwhile, the discharge auxiliary unit 330 may form a bypass path that can discharge the residual voltage in the discharge unit 320 when the discharge unit 320 itself cannot discharge the residual voltage.

In order to perform the above-described operation, the discharge auxiliary unit 330 according to the embodiment may include a second switching element S2 and a connection unit 332. The second switching element S2 may be turned on when the residual voltage cannot be discharged in the discharge unit 320 itself. For example, the second switching element S2 may be implemented in the form of a relay element S2A, but the embodiment is not limited to a specific form of the second switching element S2. The connection unit 322 may connect the other side of each of the first to M resistors (R1 to RM) (Rm) to the second output terminal (OUT2) of the cell stack 310 when the second switching element (S2) is turned on. . For example, the connection portion 322 may be a type of wiring.

According to an embodiment, the second switching element (S2) is turned off in response to the first switching control signal (SC1) of the first level, and when the first switching control signal (SC1) is not generated or is turned off in response to the first switching control signal (SC1) of the second level. It may be turned on in response to the first switching control signal SC1. In this way, the second switching element S2 may be a type of normally close type switch.

The switching unit 340 of the vehicle 300 described above may provide the stack voltage to the load 360 in response to the second switching control signal SC2 output from the main control unit 370. When there is no need to discharge the residual voltage, the main control unit 370 may generate the second switching control signal SC2 so that the stack voltage can be provided to the load 360.

For example, the switching unit 340 may include two 3-1 and 3-2 switching elements (or, 3-1 and 3-2 relay elements) (S31, S32). The 3-1st switching element (S31) is disposed between one of the two output terminals (OUT1 and OUT2) of the cell stack 310 (OUT1) and the load 360, and is one of the second switching control signals (SC2). 2-1 It may be turned on or turned off in response to the switching control signal (S21). The 3-2 switching element (S32) is disposed between the load 360 and the other one (OUT2) of the two output terminals (OUT1, OUT2) of the cell stack 310, and the other one of the second switching control signals (SC2) It may be turned on or turned off in response to the 2-2 switching control signal (S22).

The main control unit 370 may generate the first switching control signal SC1 when generating the discharge control signal DCS and control the discharge unit 320 itself to discharge the residual voltage. That is, in a situation where the residual voltage must be discharged, if the main control unit 370 can generate the discharge control signal (DCS), the residual voltage can be discharged in the discharge unit 320 itself. When an operating voltage (for example, a “high” level 12 volt voltage) is applied from the outside for a certain period of time through the input terminal IN, the main control unit 370 checks whether there is a need to discharge the residual voltage and determines the result of the inspection. Accordingly, at least one of the discharge control signal (DCS), the first switching control signal (SC1), or the second switching control signal (SC21, S22) can be generated.

Additionally, the second switching element S2 may be turned off or on in response to the first switching control signal SC1 generated by the main control unit 370. However, in a situation where the residual voltage must be discharged, if the main control unit 370 cannot generate the discharge control signal (DCS), the residual voltage cannot be discharged from the discharge unit 320 itself, so the assistance of the discharge auxiliary unit 330 is used. The residual voltage can be discharged by . To this end, even in a situation where the main control unit 370 cannot generate the first switching control signal SC1, the second switching element S2 can be turned on.

The main control unit 370 may use at least one of the startup inspection unit 380 and the collision inspection unit 350 to check whether there is a need to discharge the residual voltage.

The start-up inspection unit 380 may check whether the engine of the fuel cell vehicle 300 has stopped (or has been shut down) and output the test result to the main control unit 370. The main control unit 370 generates at least one of a discharge control signal (DCS), a first switching control signal (SC1), or a second switching control signal (SC21, S22) in response to the result inspected by the start-up inspection unit 380. You can.

The collision inspection unit 350 may check whether the fuel cell vehicle 300 has collided and output the inspection result to the main control unit 370. The main control unit 370 generates at least one of a discharge control signal (DCS), a first switching control signal (SC1), or a second switching control signal (SC21, S22) in response to the result inspected by the collision inspection unit 350. You can.

Hereinafter, a method of discharging residual energy (or residual voltage) of the cell stack 310 in the vehicle 300 having the above-described configuration will be described with reference to the attached drawings.

FIG. 3 is a flowchart for explaining a method of discharging residual energy according to an embodiment performed in the vehicle 300 shown in FIG. 1 .

The vehicle 300 according to the embodiment may perform a residual energy discharging method different from the method shown in FIG. 3, and the residual energy discharging method according to the embodiment may be performed by the vehicle 300 having a configuration different from that shown in FIG. 1. ) can also be performed.

First, it is checked whether there is a need to discharge the residual voltage of the cell stack 310 (steps 510 and 512).

For example, the step of checking whether it is necessary to discharge residual voltage in the vehicle 300 includes checking whether the engine of the vehicle 300 has stopped (step 510) or checking whether the vehicle 300 has collided. It may include at least one of the steps (step 512).

According to one embodiment, as shown in FIG. 3, it is checked whether the engine of the vehicle 300 has stopped (step 510). If it is determined that the vehicle 300 has not started, it is checked whether the vehicle 300 has collided (step 512).

According to another embodiment, unlike shown in FIG. 3, it is first checked whether the vehicle 300 has collided (step 512). If it is determined that the vehicle 300 has not collided, it is checked whether the engine of the vehicle 300 has stopped (step 510).

Step 510 may be performed in the start-up inspection unit 380, and step 512 may be performed in the collision inspection unit 350.

If it is determined that the engine of the vehicle 300 has stopped or the vehicle 300 has not collided through the results of the inspection by the start-up inspection unit 380 and the collision inspection unit 350, the main control unit 370 determines the remaining cell stack 310. It is decided that there is no need to discharge the voltage. At this time, the main control unit 370 uses the discharge control signal (DCS) and the first switching control signal (SC1) to prevent the discharge unit 320 from discharging the residual voltage and to allow the discharge auxiliary unit 330 to It can be controlled not to assist discharge. Additionally, the main control unit 370 controls the stack voltage to be provided to the load 360 using the second switching control signal (SC2:SC21, SC22) (step 520).

For example, if it is determined that the engine of the vehicle 300 has not stopped and the vehicle 300 has not collided, the main control unit 370 determines that there is no need to discharge the residual voltage of the cell stack 310, and determines that the first A discharge control signal (DCS) of a level, a first switching control signal (SC1) of a first level, and a second switching control signal of a first level (SC2:SC21, SC22) may be generated and output. In particular, in order for the main control unit 370 to generate the discharge control signal (DCS), the first switching control signal (SC1), and the second switching control signal (SC2:SC21, SC22), an operating voltage is provided through the input terminal IN, such as A voltage of 12 volts needs to be applied to the main control unit 370 for a certain period of time.

The sub-controller 322 does not generate a driving signal when the first level discharge control signal (DCS) is generated and applied to the main control part 370. Accordingly, since the 1-1st to 1-Mth first switching elements (S11 to S1M) are turned off, the output of the cell stack 310 applied to the first to Mth resistors (R1 to RM) is discharged. is not formed, so no discharge operation occurs in the discharge unit 320.

The second switching element S2 may be turned off when the first switching control signal SC1 of the first level is applied from the main control unit 370.

In addition, the 3-1 and 3-2 switching elements (S31, S32) of the switching unit 340 are connected to the 2-1 and 2-2 switching control signals (SC2:SC21, SC22) of the first level, respectively. It can be turned on in response. Accordingly, the stack voltage generated in the cell stack 310 may be provided to the load 360.

Alternatively, when the discharge unit 320 is implemented as a COD heater, the COD heater may perform the above-described additional function, that is, an operation of heating the coolant, while step 520 is performed. In this case, under the control of the main control unit 370, the second switching element (S2) is turned off, and the 3-1 and 3-2 switching elements (S31 and S32) of the switching unit 340 are turned off or It can be turned on, and the sub-controller 322, under the control of the main control unit 370, generates the first to M-th driving signals to the 1-1st to 1-Mth first switching elements (S11 to S1M), respectively. can be provided.

On the other hand, if it is determined that the engine of the vehicle 300 has stopped or the vehicle 300 has collided through at least one of the inspection results in the start-up inspection unit 380 or the collision inspection unit 350, the residual voltage is generated in the discharge unit 320 itself. Check whether it is possible to discharge (step 530).

The main control unit 370 may be damaged due to various reasons, such as the engine room being deformed when the vehicle 300 crashes, or an operating voltage provider (not shown) that provides an operating voltage from the vehicle 300 to the main control unit 370. (e.g., 12 volt power supply unit) is damaged, the wiring that provides the operating voltage from the operating voltage provider in the vehicle 300 to the main control unit 370 is damaged, or the discharge unit 320 is damaged from the main control unit 370. ) There may be a situation in which the discharge unit 320 itself cannot discharge the residual voltage due to various reasons, such as damage to the wiring (L) through which the discharge control signal (DCS) is provided.

According to one embodiment, step 530 may be performed by the main control unit 370. For example, when determining that it is necessary to discharge the residual voltage of the cell stack 310, the main control unit 370 operates the discharge unit 320 itself when an operating voltage is applied from the outside through the input terminal IN for a certain period of time. By determining that the residual voltage can be discharged, a second level discharge control signal (DCS) can be generated.

According to another embodiment, step 530 may also be performed by the sub-controller 322 and the discharge auxiliary unit 330. For example, a second level discharge control signal (DCS) is generated in the main control unit 370, but due to reasons such as a collision with the vehicle 300, the discharge control signal (DCS) is provided to the discharge unit 320. The wiring (L) may be broken. In addition, when the second level discharge control signal (DCS) is not received from the main control unit 370 due to the various reasons described above, the sub control unit 322 switches the 1-1 to 1-M switching elements (S11). to S1M) cannot be generated. That is, when the 1-1st to 1-Mth driving signals are not generated and the 1-1st to 1-Mth switching elements (S11 to S1M) are turned off, a path for discharging the residual voltage is formed in the discharge unit 320. As a result, the residual voltage cannot be discharged in the discharge unit 320 itself.

If the residual voltage can be discharged in the discharge unit 320 itself, the residual voltage in the cell stack 310 is discharged in the discharge unit 320 itself (step 540). That is, step 540 may be performed in the discharge unit 320 itself.

For example, when it is determined that the engine of the vehicle 300 has stopped or the vehicle 300 has crashed, the main control unit 370 determines that it is necessary to discharge the residual voltage of the cell stack 310, and determines that the residual voltage of the cell stack 310 needs to be discharged. A discharge control signal (DCS), a first switching control signal (SC1) of a first or second level, and a second switching control signal (SC2:SC21, SC22) of a second level may be generated and output. As described above, the main control unit 370 uses an operating voltage through the input terminal IN to generate the discharge control signal (DCS), the first switching control signal (SC1), and the second switching control signal (SC2:SC21, SC22). For example, a voltage of 12 volts must be applied to the main control unit 370 for a certain period of time.

When the second level discharge control signal (DCS) is applied from the main control unit 370, the sub-controller 322 generates the 1st to Mth driving signals and switches the 1-1st to 1-Mth first switching elements. (S11 to S1M) are output respectively. Accordingly, in response to the first to Mth driving signals, each of the 1-1st to 1-Mth first switching elements (S11 to S1M) is turned on, and the voltage applied to the first to Mth resistors (R1 to RM) is turned on. By forming a path through which the residual voltage of the cell stack 310 is discharged, the residual voltage can be discharged in the discharge unit 320 itself. As shown in FIG. 1, when the residual voltage is discharged in the discharge unit 320 itself, discharge current may flow along the paths I1A to IMA.

The second switching element S2 may be turned on when the first switching control signal SC1 of the second level is applied from the main control unit 370. When the discharge control signal DCS of the second level is generated, the main control unit 370 may generate the first switching control signal SC1 of the first level or the second level. If the main control unit 370 generates the first switching control signal SC1 of the first level when the second level discharge control signal DCS is generated, the residual voltage is discharged only in the discharge unit 320 itself. do. However, when the second level discharge control signal DCS is generated, if the main control unit 370 generates the second level first switching control signal SC1, the residual voltage is not only in the discharge unit 320 but also in the discharge unit 320. Discharge may also occur through a bypass path formed by the connection portion 332 of the auxiliary portion 330. As shown in FIG. 1, when the residual voltage is discharged in the bypass path 332 of the discharge auxiliary unit 332, discharge current may flow along the paths I1B to IMB.

In addition, the 3-1 and 3-2 switching elements (S31, S32) of the switching unit 340 are connected to the 2-1 and 2-2 switching control signals (SC2:SC21, SC22) of the second level, respectively. It may be turned off in response. Therefore, when it is necessary to discharge the residual voltage, the stack voltage generated in the cell stack 310 cannot be provided to the load 360.

However, when the residual voltage cannot be discharged in the discharge unit 320 itself, a bypass path through which the residual voltage can be discharged is formed in the discharge unit 320 to discharge the residual voltage (step 550). Step 550 may be performed in the first to M resistors (R1 to RM) of the discharge unit 320 and the discharge auxiliary unit 330.

Ultimately, the vehicle 300 according to the above-described embodiment can have various advantages as follows.

If a mechanical switch having a mechanical contact point is used as the 1-1st to 1-M switching elements (S11 to S1M) of the discharge unit 320, it is difficult to secure operational durability for the life of the vehicle due to frequent contact opening and closing operations. I can't. For example, the mechanical durability life of a mechanical switch is approximately hundreds of thousands of cycles.

However, according to the embodiment, the 1-1 to 1-M switching elements (S11 to S1M) use semi-permanent semiconductor switches without mechanical contacts, for example, IGBTs, so that the discharge part is damaged despite the vehicle durability. (320) semi-permanent operational durability can be secured. In addition, when semiconductor switches such as IGBT are used as the 1-1 to 1-M switching elements (S11 to S1M), high-speed switching is possible and the discharge amount of the residual voltage can be actively and arbitrarily controlled. For example, the amount of discharge can be adjusted by controlling the duty ratio at which the IGBT turns on/off.

If the discharge unit 320 uses an IGBT as the 1-1st to 1-M switching elements (S11 to S1M) and the discharge auxiliary unit 330 does not exist, the 1-1 to 1-M switching elements If a driving signal for driving the elements S11 to S1M is not generated from the sub-controller 322, the residual voltage cannot be discharged.

For example, when the vehicle 300 crashes, the main control unit 370 is damaged, or an operating voltage provider (not shown) that provides an operating voltage from the vehicle 300 to the main control unit 370 (e.g., an auxiliary The battery) is damaged, the wiring that provides the operating voltage (for example, 12 volts) from the operating voltage provider to the main control unit 370 is damaged, or the discharge control signal from the main control unit 370 to the discharge unit 320 is damaged. The sub-controller due to various reasons, such as damage to the wiring (L) through which (DCS) is provided, or the wiring through which the first switching control signal (SC1) is provided from the main control unit 370 to the second switching element (SC2) is damaged. A driving signal may not be generated from 322. As such, if the residual voltage in the cell stack 310 must be discharged and the residual voltage cannot be discharged in the discharge unit 320, a secondary electric shock accident or electrical fire may occur.

However, in the case of the vehicle 300 according to the embodiment, when the residual voltage of the cell stack 310 must be discharged and the discharge unit 320 cannot discharge the residual voltage on its own, or when the first or When the two-level first switching control signal SC1 is not provided from the main control unit 370, the second switch element S2 is turned on. Accordingly, the connection portion 332 of the discharge auxiliary unit 330 is formed as a bypass path by the turned-on second switching element S2, and the discharge current flows along the bypass paths I1B to IMB, so that the residual voltage is discharged. It can be.

Ultimately, when the driving signal cannot be applied to the 1-1st to 1-M switching elements (S11 to S1M) in a situation where the residual voltage of the cell stack 310 must be discharged, the vehicle 300 according to the embodiment By discharging the residual voltage of the cell stack 310 using the discharge auxiliary unit 330, the electrical energy remaining in the cell stack 310 can be consumed and reduced below a certain level, thereby ensuring electrical stability. Due to this, the vehicle 300 according to the embodiment can guarantee the residual energy discharge function of the cell stack 310 and has high reliability.

The various embodiments described above may be combined with each other as long as they do not deviate from the purpose of the present invention and do not conflict with each other. Additionally, among the various embodiments described above, if a component of an embodiment is not described in detail, descriptions of components having the same reference numerals in other embodiments may be applied.

Although the above description focuses on examples, this is only an example and does not limit the present invention, and those skilled in the art will understand that the examples are as follows without departing from the essential characteristics of the present example. You will see that various variations and applications are possible. For example, each component specifically shown in the examples can be modified and implemented. And these variations and differences in application should be construed as being included in the scope of the present invention as defined in the appended claims.

300: vehicle

Claims (15)

A cell stack in which a plurality of unit cells are stacked;
a discharge unit that discharges residual voltage output from both output terminals of the cell stack in response to a discharge control signal;
a discharge auxiliary unit that forms a bypass path through which the residual voltage can be discharged in the discharge unit when the residual voltage cannot be discharged in the discharge unit itself; and
A fuel cell vehicle comprising a main control unit that generates the discharge control signal when it is necessary to discharge the residual voltage. The method of claim 1, wherein the discharge unit
a sub-controller generating at least one driving signal in response to the discharge control signal;
a heat dissipation resistance stage including at least one resistor on one side of which is connected to a first output terminal connected to a high potential level of the residual voltage among the two output terminals of the cell stack; and
At least one first switching device connected between the other side of the at least one resistor and a second output terminal connected to a low potential level of the residual voltage among the two output terminals of the cell stack, and switching in response to the at least one driving signal A fuel cell vehicle including the device. The method of claim 2, wherein the at least one driving signal includes first to Mth driving signals (where M is a positive integer of 2 or more),
The at least one resistor is connected in parallel with each other and includes first to Mth resistors, each of which has one side connected to the first output terminal,
The at least one first switching element switches in response to the first to Mth driving signals, respectively, and 1-1 to 1st switching elements are respectively connected between the other side of the first to Mth resistors and the second output terminal. -Fuel cell vehicle including M switching element. The method of claim 3, wherein each of the first to Mth resistors is
A fuel cell vehicle that includes a sheath heater, ceramic heater, electrical resistance element, or PTC (Positive Temperature Coefficient) resistor. 3. The fuel cell vehicle of claim 2, wherein the at least one first switching element includes a semiconductor switch. The method of claim 5, wherein the semiconductor switch is
Fuel cell vehicles that include IGBTs, Silicon Controlled Rectifiers (SCRs), Gate Turn Off Thyristors (GTOs), Bipolar Junction Transistors (BJTs), or Metal Oxide Semiconductor Field Effect Transistors (MOSFETs). The fuel cell vehicle of claim 2, wherein the discharge unit includes a COD heater. The method of claim 2, wherein the discharge auxiliary unit
a second switching element that turns on when the residual voltage cannot be discharged in the discharge unit itself; and
A fuel cell vehicle comprising a connection portion connecting the other side of the at least one resistor to the second output terminal of the cell stack when the second switching element is turned on. According to clause 8,
The second switching element is a normally closed type that is turned off in response to the first switching control signal and turned on when the first switching control signal is not generated,
The main control unit generates the first switching control signal when the discharge control signal is generated. According to clause 9,
In response to a second switching control signal, it further includes a switching unit that provides stack voltage output from both output terminals of the cell stack to a load,
The main control unit generates the second switching control signal in response to a result of checking whether the residual voltage needs to be discharged. The method of claim 10, wherein the main control unit
A fuel cell vehicle that generates at least one of the discharge control signal, the first switching control signal, and the second switching control signal according to a result of checking whether it is necessary to discharge the residual voltage when an operating voltage is applied. The method of claim 11, further comprising a start-up inspection unit that checks whether the fuel cell vehicle has stopped starting,
The main control unit generates at least one of the discharge control signal, the first switching control signal, and the second switching control signal in response to a result inspected by the start-up inspection unit. The method of claim 12, further comprising a collision inspection unit that checks whether the fuel cell vehicle has collided,
The main control unit generates at least one of the discharge control signal, the first switching control signal, and the second switching control signal in response to a result inspected by the collision inspection unit. In the residual energy discharge method performed in a fuel cell vehicle including a fuel cell including a cell stack in which a plurality of unit cells are stacked, and a discharge unit for discharging residual voltage of the cell stack,
checking whether there is a need to discharge residual voltage of the cell stack;
When it is necessary to discharge the residual voltage of the cell stack, checking whether the residual voltage can be discharged in the discharge unit itself;
discharging the residual voltage in the discharge unit itself when the residual voltage can be discharged in the discharge unit itself; and
A method of discharging residual energy in a fuel cell vehicle, including the step of discharging the residual voltage in the discharge unit through a bypass path when the residual voltage cannot be discharged in the discharge unit itself. The method of claim 14, wherein the step of checking whether there is a need to discharge the residual voltage includes
checking whether the engine of the fuel cell vehicle has stopped; or
At least one step of checking whether the fuel cell vehicle has crashed,
A method for discharging residual energy in a fuel cell vehicle for determining that the residual voltage needs to be discharged when the fuel cell vehicle is stopped or the fuel cell vehicle is in a collision.

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