Power distribution method for multi-stack fuel cell system

Abstract

The invention relates to the technical field of multi-stack fuel cell systems, in particular to a power distribution method for a multi-stack fuel cell system. According to the distribution method, the efficiency of the whole fuel cell system is improved based on a power distribution method of an optimal efficiency interval, and continuous operation of a certain electric pile is avoided based on a random distribution method of accumulated hydrogen consumption, so that the operation time of each electric pile is basically similar, and the long service life of the whole fuel cell system is ensured.

Description

Technical Field

[0001] The present invention relates to a power distribution method, and in particular to a power distribution method for a multi-stack fuel cell system. Background Art

[0002] Hydrogen energy, as a clean energy that is expected to replace traditional fossil energy, has broad application prospects. In this context, fuel cells stand out as devices that can directly convert the chemical energy in hydrogen into electrical energy. Among them, proton exchange membrane fuel cells are widely used in the automotive field. With the expansion of application scenarios such as trams, high-speed trains, locomotives and ships, the demand for high-power fuel cell systems is growing. However, at present, high-power fuel cells have not yet completely broken through in technology and materials. In order to solve this problem, various locomotive manufacturers use a multi-stack fuel cell system architecture to replace the development of a single high-power fuel cell system.

[0003] As a strongly coupled multi-physical system, the performance and life of the fuel cell system largely depend on its operating state and operating parameters. At present, the power allocation methods for multi-stack fuel cell systems include average power allocation method, chain power allocation method and adaptive power allocation method. The average power allocation method is to evenly distribute the required power to the sub-stacks, and all the stacks have the same output power. This allocation strategy is relatively simple but has low efficiency in the low power range; the chain power allocation method is to activate the stacks in a certain order. In this strategy, only after the output power of the previous stack reaches the maximum value, the next stack is allowed to supplement the remaining required power, but it is easy for a certain stack to continue to operate and then age seriously; the adaptive power allocation method is to use a certain algorithm mechanism to allocate the power of the stack, which optimizes the disadvantages of the first two methods to a certain extent, but the complex algorithm undoubtedly increases the complexity of the system. Summary of the invention

[0004] The present invention aims to solve the above-mentioned defects and provides a power distribution method for a multi-stack fuel cell system.

[0005] In order to overcome the defects in the background technology, the technical solution adopted by the present invention to solve the technical problem is: the power distribution method of the multi-stack fuel cell system includes: S1. Before the multi-stack system is put into operation, the power range [a, b] and target power P corresponding to the optimal efficiency range of a single stack are input in advance; S2. After input, determine whether P / n is within the interval [a, b], where n is the number of fuel cell stacks in the multi-stack fuel cell system. If yes, all fuel cell stacks are operated at the power of P / n. If not, proceed to the next step. S3. If it is not within the interval, continue to determine whether P / (n-1) is within the interval [a, b]. If so, randomly assign n-1 stacks to operate at P / (n-1) power. If it is still not within the interval, continue to determine whether P / 2 is within the interval [a, b]. If so, randomly assign 2 stacks to operate at P / 2 power. If not, proceed to the next step. S4. Randomly assign one battery stack to operate at power P.

[0006] According to another embodiment of the present invention, the rated power p of a single fuel cell stack in step S1 should be less than or equal to the upper limit b of a specified efficiency range, that is, p≦b, and each single stack in the multi-stack fuel cell system has the same performance.

[0007] According to another embodiment of the present invention, the step S4 is further divided into two cases, one is P∈[a,b], and the other is P∉[a,b], that is, P≦a.

[0008] According to another embodiment of the present invention, the random allocation in step S4 is further corrected by the accumulated hydrogen consumption of the fuel cell stack.

[0009] According to another embodiment of the present invention, the random allocation is further included in the process of being corrected by the cumulative hydrogen consumption of the fuel cell stack: the first step is to obtain the number of fuel cells that need to be operated and the target operating power of each fuel cell stack according to the power allocation method; the second step is to randomly allocate the operating tasks to the fuel cell stacks, and correct the allocation probability by the cumulative hydrogen consumption of each fuel cell stack; the third step is to reallocate when the power changes significantly, and the fuel cell stacks that do not need to be operated enter the idle state, and the allocation probability is corrected by the cumulative hydrogen consumption of the fuel cell stacks.

[0010] The beneficial effects of the present invention are as follows: this multi-stack fuel cell system power allocation method combines the advantages of the average power allocation method and the chain power allocation method, ensuring that each stack is within the most appropriate operating power range, overcoming the problem of low efficiency of the multi-stack fuel cell system, and at the same time, the random allocation mechanism based on the cumulative hydrogen consumption correction will not cause a certain stack to operate continuously, thereby achieving high-efficiency and long-life operation of the multi-stack fuel cell system. The present invention allows the entire multi-stack fuel cell system to be in a high-efficiency working range for a long time, while avoiding the life attenuation caused by a certain stack working for a long time, ensuring the economy and reliability of the multi-stack fuel cell system, and has the following advantages: The stack is within the optimal operating range under most operating conditions; Improve the overall efficiency of the fuel cell system; Multiple battery stacks have the same operating time, ensuring long life operation; Simple design, easy to implement and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0012] Figure 1 It is a structural schematic diagram of the flow chart of the present invention; Figure 2 It is a structural schematic diagram of the flow chart of the random allocation mechanism based on the correction of the cumulative hydrogen consumption. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] A power allocation method for a multi-stack fuel cell system based on high efficiency and long life, according to the power range corresponding to the optimal efficiency range of the fuel cell stack, obtains the number of stacks that need to be operated and the target power of each stack; randomly allocates the working stacks, and corrects them by accumulating hydrogen consumption to ensure that the operating time of each stack is basically the same. The present invention allows the entire multi-stack fuel cell system to be in a high-efficiency working range for a long time, while avoiding the life attenuation caused by a certain stack working for a long time, ensuring the economy and reliability of the multi-stack fuel cell system.

[0015] The power distribution method of a multi-stack fuel cell system includes: S1. Before the multi-stack system is put into operation, the power range [a, b] and target power P corresponding to the optimal efficiency range of a single stack are input in advance; S2. After input, determine whether P / n is within the interval [a, b], where n is the number of fuel cell stacks in the multi-stack fuel cell system. If yes, all fuel cell stacks are operated at the power of P / n. If not, proceed to the next step. S3. If it is not within the interval, continue to determine whether P / (n-1) is within the interval [a, b]. If so, randomly assign n-1 stacks to operate at P / (n-1) power. If it is still not within the interval, continue to determine whether P / 2 is within the interval [a, b]. If so, randomly assign 2 stacks to operate at P / 2 power. If not, proceed to the next step. S4. Randomly assign one battery stack to operate at power P.

[0016] Among them, the rated power p of a single fuel cell stack in step S1 should be less than or equal to the upper limit b of the specified efficiency range, that is, p≦b, and each single stack in the multi-stack fuel cell system has the same performance.

[0017] Among them, step S4 is divided into two cases, one is P∈[a,b], and the other is P∉[a,b], that is, P≦a. Different road conditions require different power during vehicle driving. When the target power changes, it needs to be re-determined. At this time, two situations will occur. The first is that the power is adjusted slightly, and the number of battery stacks finally allocated will not change, only the power will change. This situation will not have much impact on the operating status of the battery stack; the second situation is that the power changes significantly, and the number of working battery stacks calculated by this allocation method also changes. For example, 4 battery stacks were needed at the last time, and only 2 battery stacks are needed after the target power changes. At this time, 2 two battery stacks do not need to work, but in order to cope with the subsequent power changes, two random battery stacks are unloaded to idle state to avoid repeated start and stop damage to the battery stack.

[0018] Among them, the random allocation in step S4 needs to be corrected by the cumulative hydrogen consumption of the fuel cell. The process of random allocation corrected by the cumulative hydrogen consumption of the fuel cell is as follows: the first step is to obtain the number of fuel cells that need to be operated and the target power of each fuel cell according to the power allocation method; the second step is to randomly allocate the operating tasks to the fuel cell, and correct the allocation probability by the cumulative hydrogen consumption of each fuel cell; the third step is to redistribute when the power changes significantly, and the fuel cell that does not need to be operated enters the idle state, and the allocation probability is corrected by the cumulative hydrogen consumption of the fuel cell.

[0019] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A power distribution method for a multi-stack fuel cell system, characterized in that: The allocation method includes: S1. Before the multi-stack system is put into operation, the power range [a, b] and target power P corresponding to the optimal efficiency range of a single stack are input in advance; S2. After input, determine whether P / n is within the interval [a, b], where n is the number of fuel cell stacks in the multi-stack fuel cell system. If yes, all fuel cell stacks are operated at the power of P / n. If not, proceed to the next step. S3. If it is not within the interval, continue to determine whether P / (n-1) is within the interval [a, b]. If so, randomly assign n-1 stacks to operate at P / (n-1) power. If it is still not within the interval, continue to determine whether P / 2 is within the interval [a, b]. If so, randomly assign 2 stacks to operate at P / 2 power. If not, proceed to the next step. S4. Randomly assign one battery stack to operate at power P.

2. A multi-stack fuel cell system power distribution method as claimed in claim 1, characterized in that: In step S1, the rated power p of a single fuel cell stack should be less than or equal to the upper limit b of the specified efficiency range, that is, p≦b, and each single stack in the multi-stack fuel cell system has the same performance.

3. A multi-stack fuel cell system power distribution method as claimed in claim 1, characterized in that: The step S4 is divided into two cases, one is P∈[a,b], and the other is P∉[a,b], that is, P≦a.

4. A multi-stack fuel cell system power distribution method as claimed in claim 1, characterized in that: The random allocation in step S4 needs to be corrected by the accumulated hydrogen consumption of the fuel cell stack.

5. A multi-stack fuel cell system power distribution method as claimed in claim 4, characterized in that: The process of random allocation and correction by cumulative hydrogen consumption of the fuel cell stack is as follows: first, the number of fuel cells to be operated and the target operating power of each fuel cell stack are obtained according to the power allocation method; second, the operating tasks are randomly allocated to the fuel cells, and the allocation probability is corrected by the cumulative hydrogen consumption of each fuel cell stack; The third step is to redistribute the power when there is a significant change in power. The fuel cell stack that does not need to run enters the idle state, and the allocation probability is corrected by the accumulated hydrogen consumption of the fuel cell stack.

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