Power taking device and fuel cell system

Abstract

The utility model provides an electricity taking device and a fuel cell system, the positive input end of the electricity taking device is used for connecting the positive output end of an external electric pile, and the negative input end of the electricity taking device is used for connecting the negative output end of the external electric pile; the positive input end of the isolated DC-DC power supply module is connected with the positive input end of the power taking device; the negative input end of the isolation DC-DC power supply module is connected with the negative input end of the power taking device; the negative output end of the isolation DC-DC power supply module is also connected with the positive input end of the isolation DC-DC power supply module; the positive output end of the isolated DC-DC power supply module is connected with the first positive output end of the power taking device, and the negative input end of the isolated DC-DC power supply module is connected with the first negative output end of the power taking device; the first positive output end and the first negative output end of the power taking device are used for supplying power to external equipment; and the controller is electrically connected with the isolation DC-DC power supply module. Under the condition of the same output power consumption, heat energy loss can be reduced, system efficiency is improved, and energy conservation and environmental protection are achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to fuel cell field, especially relate to a kind of power taking device and fuel cell system. BACKGROUND

[0002] The abbreviation of fuel cell BOP is Balance of Plant (BOP), indicating "system balance assembly". It refers to all components in fuel cell except fuel cell stack, refers to the high-pressure water pump of cooling system, PTC (positive temperature coefficient) heater, air pressure machine high-pressure component of air path, cooling circuit radiator fan, etc., is the key component for guaranteeing the normal operation of fuel cell system.

[0003] Fuel cell system BOP (air pressure machine about 42KW, water pump 2KW, heater 15KW and other high-pressure components) power consumption loss is an important factor affecting the efficiency of the whole system. With the increase of fuel cell system power, the power consumption of two-stage compression centrifugal air pressure machine will be greater, and the energy loss will be greater and greater. The power performance parameter requirement of water pump is also higher and higher. How to improve efficiency, reduce energy loss and improve system utilization efficiency has become a topic of concern. The traditional power taking mode is to take power from lithium battery to supply power to BOP, which results in large system energy loss and low utilization efficiency. SUMMARY

[0004] The technical problem to be solved by the utility model is to overcome the defects of large energy loss and low utilization efficiency of the prior art fuel cell system BOP, and to provide a power taking device and fuel cell system.

[0005] The utility model solves the above technical problem by the following technical scheme:

[0006] In the first aspect, a power taking device is provided, which is applied to a fuel cell system, and the power taking device comprises an isolated DC-DC power supply module, a controller, a positive input end, a negative input end, a first positive output end and a first negative output end.

[0007] The positive input end of the power taking device is used to connect the positive output end of an external stack, and the negative input end of the power taking device is used to connect the negative output end of the external stack.

[0008] The positive input end of the isolated DC-DC power supply module is connected with the positive input end of the power taking device, and the negative input end of the isolated DC-DC power supply module is connected with the negative input end of the power taking device.

[0009] The negative output end of the isolated DC-DC power supply module is also connected with the positive input end of the isolated DC-DC power supply module.

[0010] The positive output end of the isolated DC-DC power module is connected with the first positive output end of the power taking device, and the negative input end of the isolated DC-DC power module is connected with the first negative output end of the power taking device.

[0011] The first positive output end and the first negative output end of the power taking device are used for supplying power to external equipment.

[0012] The controller is electrically connected with the isolated DC-DC power module.

[0013] Optionally, the power taking device further comprises a non-isolated DC-DC power module, a first switch assembly, a second positive output end and a second negative output end.

[0014] The positive input end of the non-isolated DC-DC power module is connected with the positive input end of the isolated DC-DC power module, and the negative input end of the non-isolated DC-DC power module is connected with the negative input end of the isolated DC-DC power module.

[0015] The positive output end of the non-isolated DC-DC power module is connected with the second positive output end, and the negative output end of the non-isolated DC-DC power module is connected with the second negative output end.

[0016] The positive output end of the non-isolated DC-DC power module is further connected with the positive output end of the isolated DC-DC power module through the first switch assembly.

[0017] The output of the first switch assembly serves as the first positive output end of the power taking device.

[0018] The controller is electrically connected with the non-isolated DC-DC power module and the first switch assembly respectively.

[0019] Optionally, the isolated DC-DC power module is a step-up / down isolated DC-DC power.

[0020] Optionally, the non-isolated DC-DC power module is a step-up non-isolated DC-DC power.

[0021] Optionally, the first switch assembly is a metal-oxide-semiconductor field effect transistor.

[0022] Optionally, the positive output end of the non-isolated DC-DC power module is connected with the second output end of the power taking device through a second switch assembly.

[0023] Optionally, a fuse is arranged between the first switch assembly and the first positive output end of the power taking device.

[0024] Optionally, a first voltage detection component is arranged between the positive input end of the power taking device and the negative output end of the power taking device, and the first voltage detection component is electrically connected with the controller.

[0025] Optionally, a first current detection component is arranged at the positive output end of the isolated DC-DC power supply module, and the first current detection component is electrically connected with the controller.

[0026] Optionally, a second voltage detection component is arranged between the positive output end of the isolated DC-DC power supply module and the negative output end of the isolated DC-DC power supply module, and the second voltage detection component is electrically connected with the controller.

[0027] Optionally, a second current detection component is arranged at the positive input end of the isolated DC-DC power supply module, and the second current detection component is electrically connected with the controller.

[0028] Optionally, a third voltage detection component is arranged between the positive output end of the non-isolated DC-DC power supply module and the negative input end of the non-isolated DC-DC power supply module, and the third voltage detection component is electrically connected with the controller.

[0029] Optionally, a third current detection component is arranged at the positive input end of the non-isolated DC-DC power supply module, and the third current detection component is electrically connected with the controller.

[0030] Optionally, a fourth current detection component is arranged at the positive output end of the non-isolated DC-DC power supply module, and the fourth current detection component is electrically connected with the controller.

[0031] Optionally, the fourth voltage detection component is arranged between the second positive output end and the second negative output end of the power taking device, and the fourth voltage detection component is electrically connected with the controller.

[0032] Optionally, a fifth current detection component is arranged at the positive output end of the first switch component, and the fifth current detection component is electrically connected with the controller.

[0033] Optionally, the fifth voltage detection component is arranged between the first positive output end and the first negative output end of the power taking device, and the fifth voltage detection component is electrically connected with the controller.

[0034] In a second aspect, a fuel cell system is provided, which comprises an electric pile module and the power taking device according to any one of the above aspects, the positive input end of the electric pile module is connected with the positive input end of the power taking device, the negative input end of the electric pile module is connected with the negative input end of the power taking device, and the first positive output end and the first negative output end of the power taking device supply power externally.

[0035] Optionally, the fuel cell system further comprises a lithium battery, and the second positive output end and the second negative output end of the power taking device are connected with the lithium battery in the case that the power taking device has the second positive output end and the second negative output end.

[0036] The positive output end of the electric pile module is connected with the negative output end of the isolation DC-DC power module, so that the loss of heat energy can be reduced under the same output power consumption, energy loss is reduced, system efficiency is improved, energy saving and environmental protection are realized, and the utilization rate of hydrogen in the fuel cell is improved. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 A circuit diagram of a power taking device is provided for an embodiment of the utility model,

[0038] Figure 2 A circuit diagram of a power taking device is provided for another embodiment of the utility model,

[0039] Figure 3 A circuit diagram of a fuel cell system is provided for an embodiment of the utility model. DETAILED DESCRIPTION

[0040] The utility model will be further illustrated by means of embodiments below, but the utility model is not limited in the scope of the embodiments.

[0041] The prefix words such as "first", "second" are used in the embodiments of the utility model only for distinguishing different description objects, and have no limiting effect on the position, order, priority, quantity or content of the described objects. The use of ordinal words such as ordinal words in the embodiments of the utility model does not constitute limitation on the described objects, and the statement of the described objects should refer to the description in the context of claims or embodiments, and should not constitute redundant limitation because of the use of such prefix words. In addition, in the description of the embodiments, unless otherwise specified, the meaning of "a plurality of" is two or more than two.

[0042] Figure 1 A circuit schematic diagram of a power taking device is provided for an embodiment of the utility model, and the power taking device in the dashed box is applied to a fuel cell system, and the power taking device comprises an isolation DC-DC power module 1, a controller 2, a positive input end DC IN+, a negative input end DC IN-, a first positive output end HV1 out+ and a first negative output end HV1 out-.

[0043] The positive input end DC IN+ of the power taking device is used for connecting the positive output end of the external electric pile, and the negative input end DC IN- of the power taking device is used for connecting the negative output end of the external electric pile.

[0044] The positive input end DC1 IN+ of the isolated DC-DC power module is connected with the positive input end DCIN+ of the power taking device; and the negative input end DC1 IN- of the isolated DC-DC power module is connected with the negative input end DC IN- of the power taking device.

[0045] The negative output end DC1 out- of the isolated DC-DC power module is also connected with the positive input end DC1 IN+ of the isolated DC-DC power module.

[0046] The positive output end DC1 out+ of the isolated DC-DC power module is connected with the first positive output end HV1 out+ of the power taking device; and the negative input end DC1 IN- of the isolated DC-DC power module is connected with the first negative output end HV1 out- of the power taking device.

[0047] The first positive output end HV1 out+ and the first negative output end HV1 out- of the power taking device are used for power supply of external equipment.

[0048] The controller 2 is electrically connected with the isolated DC-DC power module 1.

[0049] Specifically, the fuel control system controller sends a start-up instruction to the external equipment (BOP), and the BOP components (air compressor, water pump, etc.) start to work. At this time, the external stack module generates electricity and generates a voltage. The controller detects that there is a voltage V1 between the positive input end and the negative input end of the power taking device. The controller controls the isolated DC-DC power module to perform step-up and step-down work, and detects the voltage value V2 of the positive and negative output ends of the isolated DC-DC power module. Since DC1 out- is connected with DC1 in+, at this time, the power supply of the BOP is taken from the output of the isolated DC-DC power module and the stack in series, and the output voltage value is V3 = V1 + V2.

[0050] The advantages of the power taking scheme are explained by data as follows. When the external demand voltage V3 is 605V;

[0051] A. When the external stack voltage V1 is 300V and the BOP power is 50KW, at this time, the isolated DC-DC power module needs to be stepped up from 300V to 305V, and the efficiency of the isolated DC-DC power module is 97%. At this time, the output current A1 = 50KW / 605V = 82.7A. The input power of the isolated DC-DC power module is (82.7*305) / 0.97 = 26.0KW. Because of the DC conversion efficiency, the power converted into heat energy on the isolated DC-DC power module is 26.0*0.03 = 0.78KW.

[0052] B. When the external stack voltage V1 is 250V, the BOP power is 50KW, the output voltage is 605V, at this time the isolated DC-DC power module needs to be boosted from 300V to 355V, the efficiency of the isolated DC-DC power module is 97%. At this time the output current A1 = 50KW / 605V = 82.7A. The input power of the isolated DC-DC power module is (82.7*355) / 0.97 = 30.3KW. The power converted into heat energy on the isolated DC-DC power module because of the DC conversion efficiency, that is, the loss is 30.3*0.03 = 0.91KW.

[0053] C. When the external stack voltage V1 is 350V, the BOP power is 50KW, the output voltage is 605V, at this time the isolated DC-DC power module needs to be boosted from 300V to 355V, the efficiency of the isolated DC-DC power module is 97%. At this time the output current A1 = 50KW / 605V = 82.7A. The input power of the isolated DC-DC power module is (82.7*355) / 0.97 = 30.3KW. The power converted into heat energy on the isolated DC-DC power module because of the DC conversion efficiency, that is, the loss is 30.3*0.03 = 0.91KW.

[0054] In the above three working conditions, the BOP power is 50KW, the loss of the BOP power through the DC module is 1.5KW, and the loss of the BOP power through the DC module is 1.5KW. Compared with the previous comparison, the energy loss can be saved (1.5-0.91) / 1.5*100% = 40%.

[0055] In the embodiment, by connecting the positive output end of the stack module and the negative output end of the isolated DC-DC power module, the heat energy loss can be reduced under the same output power consumption, thereby reducing the energy loss, improving the system efficiency, saving energy and protecting the environment, and improving the utilization rate of hydrogen in the fuel cell.

[0056] Figure 2 The circuit schematic diagram of the power taking device provided for another embodiment of the utility model, the power taking device further includes a non-isolated DC-DC power module 3, a first switch assembly 4, a second positive output end HV2out+ and a second negative output end HV2 out+;

[0057] The positive input end of the non-isolated DC-DC power module is connected with the positive input end of the isolated DC-DC power module, and the negative input end of the non-isolated DC-DC power module is connected with the negative input end of the isolated DC-DC power module.

[0058] The positive output end of the non-isolated DC-DC power module is used as the second positive output end of the power taking device, and the negative output end of the non-isolated DC-DC power module is used as the second negative output end of the power taking device.

[0059] The positive output end of the non-isolated DC-DC power module is used as the second positive output end of the power taking device, and the negative output end of the non-isolated DC-DC power module is used as the second negative output end of the power taking device.

[0060] The positive output end of the non-isolated DC-DC power module is used as the second positive output end of the power taking device, and the negative output end of the non-isolated DC-DC power module is used as the second negative output end of the power taking device.

[0061] The positive output end of the non-isolated DC-DC power module is used as the second positive output end of the power taking device, and the negative output end of the non-isolated DC-DC power module is used as the second negative output end of the power taking device.

[0062] Specifically, when the lithium battery is in a low-voltage 24V state, the external stack is not working at this time, and the output voltage V1 of the external stack module is 0V. The fuel cell system controller issues a high-voltage connection instruction to the non-isolated DC-DC power module. The internal controller of the non-isolated DC-DC power module detects the voltage of the lithium battery, and the controller controls the first switch assembly to be closed, so that the voltage of the lithium battery is supplied to the BOP power supply port through the first switch assembly. At this time, V3=V4=V4-2. The BOP components (air compressor, water pump, etc.) have high-voltage power supply, and are in standby at this time.

[0063] When the fuel cell system controller issues a start-up operation instruction, the BOP components (air compressor, water pump, etc.) start to work, and the external stack module generates electricity to produce a voltage. The controller detects that V1 has a voltage: the controller controls the non-isolated DC-DC power module to work in an input constant current mode to charge the lithium battery; the controller controls the isolated DC-DC power module to work and detects the output voltage V2 value. Since DC1 out- and DC1in+ are connected, V1+V2 is obtained at this time. The controller controls the isolated DC-DC power module to make V2+V1 equal to V4+N (N is a positive voltage, which can be 5V-10V), controls the first switch assembly to be disconnected to take power from the lithium battery, and switches to take power from the isolated DC-DC power module. At this time, the output V3 of the power taking device is V1+V2. At this time, the power supply of the BOP is taken from the output of the isolated DC-DC power module and the stack in series.

[0064] The fuel cell system controller controls the fuel cell system to shut down, and the system goes through the shutdown process. At this time, the stack has residual electrical energy, similar to a capacitor. Through the non-isolated DC-DC power module and the isolated DC-DC power module, the residual electrical energy of the stack is reduced to consume. When the controller detects that V1 drops to a certain low value, the controller controls the first switch assembly to switch the power taking mode, disconnects the output of the isolated DC-DC power module, and switches to the lithium battery power supply to supply the remaining BOP components water pump. At this time, V4=V2.

[0065] The advantages of this power taking scheme are illustrated by the following data. When the lithium battery voltage V4 is 600V and N is 5V;

[0066] A. When the external stack voltage V1 is 300V and the BOP power is 50KW, the isolated DC-DC power supply module needs to be boosted from 300V to 305V, and the efficiency of the isolated DC-DC power supply module is 97%. At this time, the output current A1 = 50KW / 605V = 82.7A. The input power of the isolated DC-DC power supply module is (82.7*305) / 0.97 = 26.0KW. The power converted into heat energy on the isolated DC-DC power supply module due to the DC conversion efficiency, i.e. the loss, is 26.0*0.03 = 0.78KW.

[0067] B. When the external stack voltage V1 is 250V and the BOP power is 50KW, the output voltage is 605V, the isolated DC-DC power supply module needs to be boosted from 300V to 355V, and the efficiency of the isolated DC-DC power supply module is 97%. At this time, the output current A1 = 50KW / 605V = 82.7A. The input power of the isolated DC-DC power supply module is (82.7*355) / 0.97 = 30.3KW. The power converted into heat energy on the isolated DC-DC power supply module due to the DC conversion efficiency, i.e. the loss, is 30.3*0.03 = 0.91KW.

[0068] C. When the external stack voltage V1 is 350V and the BOP power is 50KW, the output voltage is 605V, the isolated DC-DC power supply module needs to be boosted from 300V to 255V, and the efficiency of the isolated DC-DC power supply module is 97%. At this time, the output current A1 = 50KW / 605V = 82.7A. The input power of the isolated DC-DC power supply module is (82.7*255) / 0.97 = 21.7KW. The power converted into heat energy on the isolated DC-DC power supply module due to the DC conversion efficiency, i.e. the loss, is 21.7*0.03 = 0.65KW.

[0069] In the above three working conditions, the BOP power taking has the largest loss of 0.91KW due to the DC boosting and reducing process. In the previous traditional power taking method, the BOP is directly powered by the lithium battery. In the same working condition, when the BOP power is 50KW, the DC module efficiency is 97%. The loss of the BOP power after boosting and reducing is: 50*0.03 = 1.5KW. Compared with the previous method, the energy loss can be saved by (1.5-0.91) / 1.5*100% = 40%.

[0070] In the embodiment, the first switch assembly is added, so that the fuel cell system can switch from lithium battery power supply to external stack power supply in the standby state to working state switching process, and can reduce the loss of thermal energy under the same output power consumption in the working state, thereby reducing energy loss and improving system efficiency.

[0071] In one embodiment, the isolated DC-DC power supply module 1 is a step-up and step-down isolated DC-DC power supply.

[0072] In one embodiment, the non-isolated DC-DC power supply module 2 is a step-up isolated DC-DC power supply.

[0073] In the above embodiment, the isolated DC-DC power supply module 1 is a step-up and step-down isolated DC-DC power supply, and the DC efficiency is 97%; the non-isolated DC-DC power supply module 2 is a step-up isolated DC-DC power supply, and the DC efficiency is 97%, thereby ensuring the working efficiency of the entire power taking device.

[0074] In one embodiment, the first switch assembly 4 is a metal-oxide-semiconductor field-effect transistor (MOSFET).

[0075] In the embodiment, the first switch assembly is a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), which can make the response time of the first switch assembly ms level, so that the switching speed is fast and the BOP equipment will not be shut down.

[0076] In one embodiment, the positive output end of the non-isolated DC-DC power supply module is connected to the second output end of the power taking device through the second switch assembly 5.

[0077] Specifically, when the low-voltage 24V state is started, the external stack is not working, and the external stack module output voltage V1=0V. The fuel cell system controller issues a high-voltage connection instruction to the non-isolated DC-DC power supply module. The non-isolated DC-DC power supply module internal controller detects the lithium battery voltage, and closes the second switch assembly 5 output relay and pre-charge circuit; at the same time, the controller controls the second switch assembly, so that the lithium battery voltage is supplied to the BOP power supply port through the second switch assembly, at this time V3=V4=V4-2. The BOP components (air compressor, water pump, etc.) have high-voltage power supply, and at this time they are in standby.

[0078] In the embodiment, the second switch assembly can make the entire fuel cell system in standby state under the control of the controller, and when the lithium battery needs to be replaced, the switch can be disconnected to facilitate replacement.

[0079] In one embodiment, the output end of the first switch assembly is provided with a fuse 6.

[0080] In the embodiment, a fuse is arranged at the output end of the first switch assembly and the first output end of the power taking device, so as to ensure the power supply safety of the external equipment and prevent the circuit from burning out.

[0081] In one embodiment, a first voltage detection assembly V1 is arranged between the positive input end of the power taking device and the negative output end of the power taking device, and the first voltage detection assembly is electrically connected with the controller.

[0082] In one embodiment, a first current detection assembly A1 is arranged at the positive output end of the isolated DC-DC power supply module, and the first current detection assembly is electrically connected with the controller.

[0083] In one embodiment, a second voltage detection assembly V2 is arranged between the positive output end of the isolated DC-DC power supply module and the negative output end of the isolated DC-DC power supply module, and the second voltage detection assembly is electrically connected with the controller.

[0084] In one embodiment, a second current detection assembly A2 is arranged at the positive input end of the isolated DC-DC power supply module, and the second current detection assembly is electrically connected with the controller.

[0085] In one embodiment, a third voltage detection assembly V4 is arranged between the positive output end of the non-isolated DC-DC power supply module and the negative input end of the non-isolated DC-DC power supply module, and the third voltage detection assembly is electrically connected with the controller.

[0086] In one embodiment, a third current detection assembly A3 is arranged at the positive input end of the non-isolated DC-DC power supply module, and the third current detection assembly is electrically connected with the controller.

[0087] In one embodiment, a fourth current detection assembly A4 is arranged at the positive output end of the non-isolated DC-DC power supply module, and the fourth current detection assembly is electrically connected with the controller.

[0088] In one embodiment, a fourth voltage detection assembly V4-2 is arranged between the second positive output end and the second negative output end of the power taking device, and the fourth voltage detection assembly is electrically connected with the controller.

[0089] In one embodiment, a fifth current detection assembly A5 is arranged at the positive output end of the first switch assembly, and the fifth current detection assembly is electrically connected with the controller.

[0090] In one embodiment, a fifth voltage detection assembly V3 is arranged between the first positive output end and the first negative output end of the power taking device, and the fifth voltage detection assembly is electrically connected with the controller.

[0091] Through the voltage current measuring Hall devices at multiple positions, the controller can monitor the working state of the whole power taking device in real time, and is also used for controlling the switching assembly to switch in time, and when a circuit fails, the controller can troubleshoot in time, and facilitate user maintenance.

[0092] Figure 3 A circuit schematic diagram of a fuel cell system is provided in an embodiment of the utility model, the fuel cell system includes a stack module and a power taking device as any one of the above, the positive input end of the stack module is connected with the positive input end of the power taking device, the negative input end of the stack module is connected with the negative input end of the power taking device, the first positive output end and the first negative output end of the power taking device supply power to the outside.

[0093] In the embodiment, by connecting the positive output end of the stack module with the negative output end of the isolation DC-DC power module, the fuel cell system can reduce the heat energy loss under the same BOP output power consumption, thereby reducing the energy loss, improving the system efficiency, saving energy and protecting the environment, and improving the utilization rate of hydrogen in the fuel cell.

[0094] In an embodiment, the fuel cell system further includes a lithium battery, and in the case that the power taking device has a second positive output end and a second negative output end, the second positive output end and the second negative output end of the power taking device are connected with the lithium battery.

[0095] In the embodiment, the lithium battery enables the fuel cell system to switch from lithium battery power supply to stack power supply during the standby state to working state switching process, and can reduce the heat energy loss under the same working state output power consumption, thereby reducing the energy loss and improving the system efficiency.

[0096] Although the specific embodiments of the utility model are described above, those skilled in the art should understand that this is only an example, the protection scope of the utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the utility model, and these changes and modifications all fall within the protection scope of the utility model.

Claims

1. A power taking device, characterized in that The power taking device is applied to a fuel cell system, and the power taking device comprises an isolated DC-DC power module, a controller, a positive input end, a negative input end, a first positive output end and a first negative output end: The positive input end of the power taking device is used for connecting a positive output end of an external stack, and the negative input end of the power taking device is used for connecting a negative output end of the external stack; The positive input end of the isolated DC-DC power module is connected with the positive input end of the power taking device, and the negative input end of the isolated DC-DC power module is connected with the negative input end of the power taking device; The negative output end of the isolated DC-DC power module is also connected with the positive input end of the isolated DC-DC power module; The positive output end of the isolated DC-DC power module is connected with the first positive output end of the power taking device, and the negative input end of the isolated DC-DC power module is connected with the first negative output end of the power taking device; The first positive output end and the first negative output end of the power taking device are used for supplying power to external equipment; The controller is electrically connected with the isolated DC-DC power module.

2. The power taking apparatus of claim 1, wherein The power taking device further comprises a non-isolated DC-DC power module, a first switch assembly, a second positive output end and a second negative output end; The positive input end of the non-isolated DC-DC power module is connected with the positive input end of the isolated DC-DC power module, and the negative input end of the non-isolated DC-DC power module is connected with the negative input end of the isolated DC-DC power module; The positive output end of the non-isolated DC-DC power module is connected with the second positive output end, and the negative output end of the non-isolated DC-DC power module is connected with the second negative output end; The positive output end of the non-isolated DC-DC power module is also connected with the positive output end of the isolated DC-DC power module through the first switch assembly; The output of the first switch assembly serves as the first positive output end of the power taking device; The controller is electrically connected with the non-isolated DC-DC power module and the first switch assembly respectively.

3. The power taking apparatus of claim 2, wherein The isolated DC-DC power module is a step-up / down isolated DC-DC power supply. And / or the non-isolated DC-DC power module is a step-up non-isolated DC-DC power supply.

4. The power taking apparatus of claim 2, wherein The first switch assembly is a metal-oxide-semiconductor field effect transistor.

5. The power taking apparatus of claim 2, wherein The positive output end of the non-isolated DC-DC power module is connected with the second output end of the power taking device through a second switch assembly.

6. The power taking apparatus of claim 2, wherein A fuse is arranged between the first switch assembly and the first positive output end of the power taking device.

7. The power taking apparatus of claim 1, wherein A first voltage detection assembly is arranged between the positive input end of the power taking device and the negative output end of the power taking device, and the first voltage detection assembly is electrically connected with the controller; And / or a first current detection assembly is arranged at the positive output end of the isolated DC-DC power module, and the first current detection assembly is electrically connected with the controller; And / or a second voltage detection assembly is arranged between the positive output end of the isolated DC-DC power module and the negative output end of the isolated DC-DC power module, and the second voltage detection assembly is electrically connected with the controller.

8. The power taking apparatus of claim 2, wherein The positive input end of the isolated DC-DC power module is provided with a second current detection component, which is electrically connected with the controller; And / or a third voltage detection component is arranged between the positive output end of the non-isolated DC-DC power module and the negative input end of the non-isolated DC-DC power module, which is electrically connected with the controller; And / or a third current detection component is arranged at the positive input end of the non-isolated DC-DC power module, which is electrically connected with the controller; And / or a fourth current detection component is arranged at the positive output end of the non-isolated DC-DC power module, which is electrically connected with the controller; And / or a fourth voltage detection component is arranged between the second positive output end and the second negative output end of the power taking device, which is electrically connected with the controller; And / or a fifth current detection component is arranged at the positive output end of the first switch component, which is electrically connected with the controller; And / or a fifth voltage detection component is arranged between the first positive output end and the first negative output end of the power taking device, which is electrically connected with the controller.

9. A fuel cell system characterized by comprising: The fuel cell system comprises a stack module and the power taking device as claimed in any one of claims 1 to 8, the positive input end of the stack module is connected with the positive input end of the power taking device, the negative input end of the stack module is connected with the negative input end of the power taking device, and the first positive output end and the first negative output end of the power taking device supply power externally.

10. The fuel cell system of claim 9, wherein, The fuel cell system further comprises a lithium battery, and in the case that the power taking device has a second positive output end and a second negative output end, the second positive output end and the second negative output end of the power taking device are connected with the lithium battery.

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