阅读说明：本技术 一种燃料电池备用电源充放电管理系统及方法 (Fuel cell standby power supply charging and discharging management system and method ) 是由 黄文英 倪梓荣 张威 刘智亮 朱伟睿 于 2021-07-23 设计创作，主要内容包括：本发明提供了一种燃料电池备用电源充放电管理系统及方法,该系统包括：燃料电池本体；启动电源,包括至少两个启动电池,所述启动电池的输出端电连接放电电路、输入端电连接充电电路,所述放电电路电连接所述燃料电池本体的启动单元；控制器,分别电连接每个所述启动电池的电源管理系统,以获取剩余电量数据；其中,在所述燃料电池本体启动时,所述控制器选择其中一个剩余电量最高的所述启动电池放电,以对所述燃料电池本体进行启动供电,并根据剩余电量大小控制其余的所述启动电池的充电与否。基于本发明的技术方案,本系统具响应快、系统联动性高、能源利用率高、使用清洁能源等特点。(The invention provides a fuel cell standby power supply charging and discharging management system and a method thereof, wherein the system comprises: a fuel cell body; the starting power supply comprises at least two starting batteries, the output ends of the starting batteries are electrically connected with a discharging circuit, the input ends of the starting batteries are electrically connected with a charging circuit, and the discharging circuit is electrically connected with the starting unit of the fuel cell body; the controller is electrically connected with the power management system of each starting battery respectively so as to obtain the residual electric quantity data; when the fuel cell body is started, the controller selects one starting battery with the highest residual electric quantity to discharge so as to start and supply power to the fuel cell body, and controls whether the rest starting batteries are charged or not according to the residual electric quantity. Based on the technical scheme of the invention, the system has the characteristics of quick response, high system linkage, high energy utilization rate, clean energy utilization and the like.)

1. A fuel cell backup power supply charge-discharge management system, comprising:

A fuel cell body;

the starting power supply comprises at least two starting batteries, the output ends of the starting batteries are electrically connected with a discharging circuit, the input ends of the starting batteries are electrically connected with a charging circuit, and the discharging circuit is electrically connected with the starting unit of the fuel cell body;

the controller is electrically connected with the power management system of each starting battery respectively so as to obtain the residual electric quantity data;

when the fuel cell body is started, the controller selects one starting battery with the highest residual electric quantity to discharge so as to start and supply power to the fuel cell body, and controls whether the rest starting batteries are charged or not according to the residual electric quantity.

2. The fuel cell backup power supply charge-discharge management system according to claim 1, further comprising:

and the output end of the photovoltaic power generation device is electrically connected with the charging circuit.

3. The system as claimed in claim 1, wherein a super capacitor is disposed in the discharge circuit to absorb a current spike at the discharge moment of the starting battery.

4. The fuel cell backup power supply charge and discharge management system according to any one of claims 1 to 3, wherein a relay switch is provided in each of said discharge circuit and said charge circuit corresponding to each of said starting cells, and said controller is electrically connected to a control terminal of said relay switch.

5. The fuel cell backup power supply charge and discharge management system according to any one of claims 1 to 3, wherein the output terminal of the start-up battery is further electrically connected to a customer premises bus.

6. A method for managing charging and discharging of a fuel cell standby power supply is characterized by comprising the following steps:

detecting a municipal power grid power-off signal;

acquiring residual electric quantity information of each starting battery in a starting power supply;

conducting a discharge circuit of a first starting battery with the highest residual capacity in the starting batteries so as to supply power to a starting unit of the fuel cell body;

and controlling whether the starting battery is charged or not according to the residual electric quantity information of the rest starting batteries.

7. The method for managing charging and discharging of a backup power supply of a fuel cell according to claim 6, wherein controlling whether the backup power supply is charged or not according to the remaining power information of the starting battery comprises:

respectively judging whether the residual electric quantity of the rest starting batteries is smaller than a first preset electric quantity threshold value;

according to the judgment result, conducting a charging circuit of the starting battery with the residual electric quantity smaller than the first preset electric quantity threshold;

and according to the judgment result, keeping the charging and discharging circuit of the starting battery with the residual electric quantity not less than the preset first electric quantity threshold disconnected.

8. The fuel cell backup power supply charge-discharge management method according to claim 6 or 7, characterized by further comprising:

when the first starting battery is discharged until the residual electric quantity is smaller than a second preset electric quantity threshold value, judging whether a second starting battery with the residual electric quantity larger than the first starting battery exists in the rest starting batteries;

if the second starting battery exists, after the discharging circuit of the first starting battery is disconnected and the charging circuit of the first starting battery is conducted, the discharging circuit of the second starting battery is conducted;

and if the second starting battery does not exist, keeping the discharge circuit of the first starting battery conducted.

9. The method for managing charging and discharging of a backup power supply for a fuel cell according to claim 8, further comprising:

and if the residual electric quantity of a plurality of starting batteries exists in the rest starting batteries and is greater than the first starting battery, taking the starting battery with the highest residual electric quantity as the second starting battery.

10. The method for managing charging and discharging of a backup power supply for a fuel cell according to claim 6, further comprising:

after the fuel cell body is started and normally outputs, disconnecting all the discharge circuits of the starting cells;

Respectively judging whether the residual electric quantity of all the starting batteries is smaller than a first preset threshold value;

and conducting the charging circuit of the starting battery with the residual electric quantity smaller than the first preset electric quantity threshold value according to the judgment result.

11. The method for managing charging and discharging of a backup power supply for a fuel cell according to claim 6, further comprising:

acquiring the battery temperature of each starting battery in the starting power supply;

and if the battery temperature of the starting battery exceeds the temperature threshold, judging the starting battery to be in an abnormal state, and completely disconnecting the corresponding charge-discharge circuit of the starting battery or reducing the charge-discharge current of the corresponding starting battery.

Technical Field

The invention relates to the technical field of power supply management, in particular to a charging and discharging management system and method for a fuel cell standby power supply.

Background

Among them, a fuel cell body supplied with hydrogen energy as an energy source is considered as a power generation device having the greatest potential, and a large number of researchers have been invested in research on the hydrogen fuel cell body. In recent years, because of frequent natural disasters, the problem that the basic power supply of the fuel cell body is interrupted due to the damage of the power supply network often occurs, so that the status of starting the power supply is increasingly highlighted.

And for the starting power supply of the fuel cell body, the shorter the response time is, the less the loss of the user is. Therefore, how to ensure that the response time of the starting power supply of the fuel cell body is as short as possible and the normal starting and operation of the fuel cell body system are the primary subjects of the normal operation of the fuel cell body system. The charge and discharge performance of the lithium battery of the starting power supply of the fuel cell body directly affects the working efficiency and the service life of the fuel cell body system, the service life of the lithium battery and the like, so how to effectively control the charge and discharge of the lithium battery is a necessary prerequisite for the high-efficiency operation of the fuel cell body.

In view of the above, a system for managing charging and discharging of a backup power source of a fuel cell is needed to solve the problems of response time of a starting power source and charging and discharging of a starting battery.

Disclosure of Invention

In view of the problems of response time of the starting power supply and charging and discharging of the starting battery to be solved urgently in the prior art, the application provides a charging and discharging management system and method for a backup power supply of a fuel battery.

In a first aspect, the present invention provides a fuel cell backup power supply charging and discharging management system, including:

a fuel cell body;

the starting power supply comprises at least two starting batteries, the output ends of the starting batteries are electrically connected with a discharging circuit, the input ends of the starting batteries are electrically connected with a charging circuit, and the discharging circuit is electrically connected with the starting unit of the fuel cell body;

the controller is electrically connected with the power management system of each starting battery respectively so as to obtain the residual electric quantity data;

when the fuel cell body is started, the controller selects one starting battery with the highest residual electric quantity to discharge so as to start and supply power to the fuel cell body, and controls whether the rest starting batteries are charged or not according to the residual electric quantity.

In one embodiment, further comprising: and the output end of the photovoltaic power generation device is electrically connected with the charging circuit.

In one embodiment, a super capacitor is disposed in the discharge circuit to absorb a current spike at the moment of discharging the starting battery.

In one embodiment, each of the discharging circuit and the charging circuit is provided with a relay switch corresponding to each of the starting batteries, and the controller is electrically connected with a control end of the relay switch.

In one embodiment, the output end of the starting battery is also electrically connected with a user terminal bus.

In a second aspect, the present invention provides a method for managing charging and discharging of a backup power supply of a fuel cell, including:

detecting a municipal power grid power-off signal;

acquiring residual electric quantity information of each starting battery in a starting power supply;

conducting a discharge circuit of a first starting battery with the highest residual capacity in the starting batteries so as to supply power to a starting unit of the fuel cell body;

and controlling whether the starting battery is charged or not according to the residual electric quantity information of the rest starting batteries.

In one embodiment, the controlling whether to charge the battery according to the remaining capacity information of the starting battery includes:

respectively judging whether the residual electric quantity of the rest starting batteries is smaller than a first preset electric quantity threshold value;

according to the judgment result, conducting a charging circuit of the starting battery with the residual electric quantity smaller than the first preset electric quantity threshold;

and according to the judgment result, keeping the charging and discharging circuit of the starting battery with the residual electric quantity not less than the preset first electric quantity threshold disconnected.

In one embodiment, further comprising:

when the first starting battery is discharged until the residual electric quantity is smaller than a second preset electric quantity threshold value, judging whether a second starting battery with the residual electric quantity larger than the first starting battery exists in the rest starting batteries;

if the second starting battery exists, after the discharging circuit of the first starting battery is disconnected and the charging circuit of the first starting battery is conducted, the discharging circuit of the second starting battery is conducted;

and if the second starting battery does not exist, keeping the discharge circuit of the first starting battery conducted.

In one embodiment, further comprising:

and if the residual electric quantity of a plurality of starting batteries exists in the rest starting batteries and is greater than the first starting battery, taking the starting battery with the highest residual electric quantity as the second starting battery.

In one embodiment, further comprising:

after the fuel cell body is started and normally outputs, disconnecting all the discharge circuits of the starting cells;

respectively judging whether the residual electric quantity of all the starting batteries is smaller than a first preset threshold value;

and conducting the charging circuit of the starting battery with the residual electric quantity smaller than the first preset electric quantity threshold value according to the judgment result.

In one embodiment, further comprising:

acquiring the battery temperature of each starting battery in the starting power supply;

and if the battery temperature of the starting battery exceeds the temperature threshold, judging the starting battery to be in an abnormal state, and completely disconnecting the corresponding charge-discharge circuit of the starting battery or reducing the charge-discharge current of the corresponding starting battery.

The features mentioned above can be combined in various suitable ways or replaced by equivalent features as long as the object of the invention is achieved.

Compared with the prior art, the charging and discharging management system and method for the fuel cell standby power supply provided by the invention at least have the following beneficial effects:

according to the charge and discharge management system and method for the standby power supply of the fuel cell, the starting batteries are arranged in the starting power supply of the fuel cell and are charged by combining systems such as a photovoltaic power generation device and the like, so that the starting batteries can be alternately used when the fuel cell is powered, and the normal and quick response of the power supply to the fuel cell at any time can be ensured; meanwhile, the battery is started to be charged and discharged circularly, and the service life of the battery is prolonged.

Drawings

The invention will be described in more detail hereinafter on the basis of embodiments and with reference to the accompanying drawings. Wherein:

FIG. 1 shows a schematic diagram of the management system of the present invention;

FIG. 2 is a control flow diagram illustrating a method for initiating battery charge/discharge management in accordance with the present invention;

fig. 3 shows a control flow diagram of the management system of the present invention.

In the drawings, like parts are provided with like reference numerals. The drawings are not to scale.

Reference numerals:

1-fuel cell body, 2-starting power supply, 21-starting battery, 211-charging circuit, 212-discharging circuit, 3-controller, 4-photovoltaic power generation device, 5-super capacitor and 6-user terminal bus.

Detailed Description

The invention will be further explained with reference to the drawings.

The management system of the invention mainly provides electric energy for the starting and normal operation of the fuel cell system through the matching of the lithium battery and the photovoltaic power generation system; when the lithium battery supplies power to the fuel cell system, charging and discharging switching among the lithium batteries is carried out to ensure normal operation of the system. In order to reach 65 ℃ close to the optimal temperature point of the fuel cell, the internal temperature of the electric pile needs to be monitored, so that the fan is controlled by the controller according to the temperature data acquired by the temperature sensor to control the rotating speed, the optimal operation temperature of the electric pile is about 65 ℃, heat generated in the power generation process of the fuel cell is blown out of the electric pile, and the working efficiency and the hydrogen utilization rate of the fuel cell are improved.

The gaps are formed between the bipolar plates of the fuel cell, oxygen in the air needs to enter the membrane electrode of the bipolar plate to react with hydrogen, the air in the fuel cell stack needs to be filtered, and if impurities in the air enter the fuel cell stack, the bipolar plate is easy to corrode, and the working efficiency and the service life of the fuel cell are influenced. An air filter is provided which must be in close proximity to the fuel cell.

Example 1

The embodiment of the invention provides a charging and discharging management system for a fuel cell standby power supply, which comprises:

a fuel cell body 1;

the starting power supply 2 comprises at least two starting batteries 21, the output end of each starting battery 21 is electrically connected with the discharge circuit 212, the input end of each starting battery 21 is electrically connected with the charging circuit 211, and the discharge circuit 212 is electrically connected with the starting unit of the fuel cell body 1;

the controller 3 is electrically connected with a power management system (BMS) of each starting battery 21 through an RS485 communication protocol to acquire remaining power (SOC) data;

when the fuel cell body 1 is started, the controller 3 selects one of the starting batteries 21 with the highest residual capacity to discharge so as to start and supply power to the fuel cell body 1, and controls whether the rest of the starting batteries 21 are charged or not according to the residual capacity.

Specifically, as shown in fig. 1 of the drawings, in the management system of the present invention, the starting power source 2 is used to supply power to a starting unit (not shown in the drawings) of the fuel cell body 1 at the time of starting the fuel cell body 1 to supply electric power required during the starting of the fuel cell body 1. The starting power supply 2 is provided with at least two starting batteries 21, the starting batteries 21 are preferably lithium batteries, and the controller 3 selects the starting battery 21 with the highest residual capacity according to the residual capacity of the starting batteries to supply power to the fuel cell body 1 and conduct the discharge circuit 212. The remaining starting batteries 21 are determined to be charged according to the remaining capacity.

Specifically, when the electric quantity of the starting battery 21 is smaller than the preset electric quantity threshold, it is determined that the starting battery needs to be charged, and at this time, the controller 3 controls the charging circuit 211 of the starting battery 21 to be turned on. In this embodiment, the preset electric quantity threshold is set to 95% of the total capacity of the starting battery 21, that is, the remaining electric quantity of the starting battery 21 is lower than 95%, that is, it indicates that it needs to be charged, and when the preset electric quantity threshold is reached, the charging is stopped.

When power is supplied to the starting of the fuel cell body 1, the residual capacity of all the starting cells 21 is monitored in real time, when the residual capacity of the starting cell 21 which supplies power to the fuel cell body 1 at present is lower than the capacity threshold lower limit, that is, the power of the starting cell 21 at present is judged to be insufficient, and the controller 3 detects whether the residual capacity of the starting cell 21 in the remaining starting cells 21 is larger than that of the starting cell 21 at present; if so, the corresponding starting battery 21 is switched to replace the current starting battery 21 to supply power to the fuel cell body 1, and after the current starting battery 21 is switched, the charging circuit 211 charges the current starting battery 21.

Note that a temperature sensor electrically connected to the controller 3 is also provided inside the fuel cell body 1 to monitor the temperature of the fuel cell body 1. Meanwhile, a heat dissipation device is also arranged corresponding to the fuel cell body 1, and a fan (air cooling) shown in the attached figure 1 can also be arranged for water cooling heat dissipation.

Further, the photovoltaic power generation device 4 is also included, and the output end of the photovoltaic power generation device 4 is electrically connected with the charging circuit 211.

Specifically, the photovoltaic power generation device 4 is used for connecting a charging circuit 211 for charging the starting battery 21; the charging circuits 211 of all the starting batteries 21 are connected in parallel and are provided with a common interface which is connected to the output of the photovoltaic generator 4. And the general interface is also connected with the output end of the fuel cell body 1 and a municipal power grid so as to replace the photovoltaic power generation device 4 to supply power for charging the starting battery 21 under the condition that the photovoltaic power generation device 4 fails or in the night environment.

When the municipal power grid is normal, the starting battery 21 is mainly charged with the photovoltaic power generation device 4 through the municipal power grid, and the photovoltaic power generation device 4 is preferred. When the municipal power grid is interrupted and the fuel cell body 1 is completely started, the starting battery 21 can be charged only by the photovoltaic power generation device 4; after the fuel cell body 1 is completely started, the fuel cell body 1 or the photovoltaic power generation device 4 can be selected as appropriate to charge the starting battery 21, and the photovoltaic power generation device 4 is still preferred. Even when municipal power grid is interrupted, before fuel cell body 1 completely starts, photovoltaic power generation device 4 can't use (the condition such as night or trouble), because have a plurality of starter cell 21 in the starting power supply 2, can alternate use, and the fault-tolerant rate is high, still can support fuel cell body 1 and start.

Further, as shown in fig. 1 of the drawings, an inverter (DCDC2) is provided at the bus interface corresponding to the charging circuit 211 of the starting battery 21 to control the charging current. The controller 3 may also detect the temperature of the starting battery 21, which may be increased during charging, and when the temperature of the starting battery 21 is higher than the first temperature threshold, the controller 3 controls the converter (DCDC2) to decrease the current to decrease the temperature. When the temperature of the starting battery 21 is higher than the second temperature threshold, the controller 3 turns off the charging circuit 211 of the starting battery 21, preventing the starting battery 21 from being damaged. The first temperature threshold and the second temperature threshold may be set according to actual conditions, and in this embodiment, the first temperature threshold is set to be 50 ℃, and the second temperature threshold is set to be 80 ℃. In the discharging process, if the temperature is abnormally increased, the control can be carried out by the same method so as to reduce the temperature or disconnect the circuit to ensure the safety.

Preferably, as shown in fig. 1, a super capacitor 5 is disposed in the discharge circuit 212 to absorb the current spike at the moment of discharging the starting battery 21. The super capacitor 5 may be disposed in correspondence to the discharge circuits 212 of all the starting batteries 21, that is, the discharge circuits 212 of all the starting batteries 21 are connected in parallel; it may be provided for the discharge circuit 212 of each starting battery 21.

In one embodiment, a relay switch is disposed in each of the discharging circuit 212 and the charging circuit 211 corresponding to each of the starting batteries 21, and the controller 3 is electrically connected to a control terminal of the relay switch.

Specifically, as shown in fig. 1 of the accompanying drawings, SW1 and SW2 in the drawing are relay switches corresponding to each starting battery 21 in the discharging circuit 212, and control on/off of the corresponding discharging circuit 212; the SW3 and the SW4 are relay switches corresponding to the respective starting batteries 21 in the charging circuit 211, and control on/off of the corresponding charging circuit 211. Further, SW5 is provided at the output end of the fuel cell body 1 to control the on/off of the power transmission circuit of the fuel cell body 1, and an inverter (DCDC1) is provided to control the output current; SW6 is arranged on a main circuit of the charging circuit 211 connected with the output end of the fuel cell body 1 and a municipal power grid, and controls the connection of the charging circuit 211 with the output end of the fuel cell body 1 and the municipal power grid to be switched on and off.

In one embodiment, the output of the start-up battery 21 is also electrically connected to the customer premises bus 6.

Specifically, the fuel cell body 1 is used as a backup power source and is started when the municipal power grid is interrupted, and at this time, the equipment at the user end cannot be supplied with the power of the municipal power grid, and meanwhile, the fuel cell body 1 is also started and cannot supply power to the user end, so that the starting battery 21 is required to supply power to the fuel cell body 1 and also supply power to the bus bar 6 at the user end, so as to support the operation of the equipment at the user end before the fuel cell body 1 completely starts power generation.

Example 2

Referring to fig. 2 and fig. 3 of the drawings, an embodiment of the present invention provides a method for managing charging and discharging of a backup power supply of a fuel cell, including:

S0：

s01: detecting whether the photovoltaic power generation device normally operates;

s02: if the photovoltaic power generation device normally operates, the connection between the charging circuit for starting the battery and other charging power supplies is disconnected;

specifically, the charging power supply comprises a photovoltaic power generation device, a municipal power grid and power output by the fuel cell body, and in general, the photovoltaic power generation device is preferentially adopted as the charging power supply for starting the battery, namely, the SW6 (relay switch) in the figure 1 is disconnected through the controller, so that the photovoltaic clean energy is energy-saving and environment-friendly.

S03: if the photovoltaic power generation device does not normally operate, the connection between the charging circuit of the battery and other charging power supplies is conducted and started;

specifically, if the photovoltaic power generation device does not operate normally, such as in a failure or night environment, the power of a municipal power grid is normally used as a charging power source of the starting battery, when the municipal power grid is interrupted, the completely started fuel cell body is used as the charging power source of the starting battery, and the municipal power grid and the fuel cell body supply power to the starting battery are connected in parallel to a main circuit, namely the SW6 on the main circuit is closed through the controller.

S04: and charging the starting batteries through corresponding charging power supplies, and disconnecting the charging circuit after the first preset electric quantity threshold value is reached.

Specifically, under the normal condition of the municipal power grid, the electric quantity of each starting battery in the starting power supply is charged to a first preset electric quantity threshold value through a corresponding charging power supply, and the enough residual electric quantity is ensured.

S1: detecting a municipal power grid power-off signal;

specifically, the controller detects the on-off of the municipal power grid in real time, and once the municipal power grid is interrupted, the controller immediately controls the fuel cell body to be started.

S11: acquiring the battery temperature of each starting battery in the starting power supply;

specifically, when the fuel cell body is started, the cell temperature of the starting cell is acquired first, and the safety of the starting cell is judged by the temperature.

S12: and if the battery temperature of the starting battery exceeds the temperature threshold, judging the battery to be in an abnormal state, and completely disconnecting the charge and discharge circuit of the corresponding starting battery or reducing the charge and discharge current of the corresponding starting battery.

Specifically, including several situations, if the battery temperature of a starting battery that is empty (the charging and discharging circuit has been completely disconnected) exceeds a temperature threshold, the battery may itself be faulty, maintain its empty state and signal an alarm to the user; if there is a battery temperature of the starting battery being charged that exceeds the temperature threshold, then it may be that the charging current is too large, at which point its charging current is reduced.

In addition, if the battery temperature of the starting battery supplying power to the fuel cell body exceeds the temperature threshold, the discharge current of the starting battery is reduced within a certain range without affecting the starting of the fuel cell body.

Further, if the battery temperature of the corresponding starting battery exceeds the temperature threshold and further reaches the upper temperature limit, if the starting battery is in a charge-discharge state, the corresponding charge-discharge circuit needs to be disconnected and an alarm is given to a user, so that the safety is ensured; for the starting battery in the discharging state, the discharging circuit is disconnected, and meanwhile, other starting batteries with normal temperature are switched to continue corresponding power supply.

S2: acquiring residual electric quantity information of each starting battery in a starting power supply;

specifically, for obtaining the information of the remaining capacity of the starting battery, it is preferable to use the starting battery with normal temperature, wherein if the battery is in a charging state, it may be a normal condition that the temperature of the battery is higher or exceeds a normal temperature threshold value, and as long as the temperature of the battery does not exceed an upper temperature limit, the information of the remaining capacity of the battery may be obtained as an alternative for supplying power to the fuel cell.

S3: conducting a discharge circuit of a first starting battery with the highest residual capacity in the starting batteries to supply power to a starting unit of the fuel cell body;

specifically, the corresponding start-up battery supplies power to the fuel cell and also supplies power to the customer premises bus to support normal operation of customer premises equipment when the fuel cell is fully started. If a plurality of starting batteries with the highest parallel residual electric quantity exist, selecting a corresponding starting battery as a first starting battery according to a certain rule, wherein the rule can be customized, such as random selection, or selecting the starting battery with the lowest temperature, or preferably leaving the starting battery vacant according to the battery state; if the specifications of the starting batteries are different, the maximum total electric quantity can be selected.

S4: controlling whether the starting battery is charged or not according to the residual electric quantity information of the rest starting batteries;

s41: respectively judging whether the residual electric quantity of the rest starting batteries is smaller than a first preset electric quantity threshold value;

specifically, in this embodiment, the first preset electric quantity threshold is set to be 95% of the total capacity of the starting battery, that is, the remaining electric quantity of the starting battery is lower than 95%, that is, it indicates that it needs to be charged, and when the charging is performed to the first preset electric quantity threshold, the charging is stopped.

S42: according to the judgment result, conducting a charging circuit of the starting battery with the residual electric quantity smaller than a first preset electric quantity threshold value;

s43: and keeping the charging and discharging circuit of the starting battery with the residual electric quantity not less than the preset first electric quantity threshold disconnected according to the judgment result.

Specifically, if the remaining power of the remaining starting battery is not less than the preset first power threshold, the charging circuit and the discharging circuit are both disconnected, and the starting battery is idle. Further, since the battery itself has a power loss when it is empty, it is preferable that the photovoltaic power generation device and the charging circuit for starting the battery are turned on at any time in order to ensure safety. In addition, due to the characteristics of the battery, the charging circuit and the discharging circuit of the same starting battery cannot be conducted simultaneously.

S5：

S51: when the first starting battery is discharged until the residual electric quantity is smaller than a second preset electric quantity threshold value, judging whether a second starting battery with the residual electric quantity larger than that of the first starting battery exists in the rest starting batteries;

specifically, the first starting battery continuously supplies power to the fuel cell body, the remaining power amount continuously decreases, when the remaining power amount decreases to a second preset power amount threshold value, the power amount is judged to be low, and the controller searches for a starting battery with the remaining power amount larger than that of the current first starting battery from other starting batteries to serve as a second starting battery which replaces the first starting battery to continuously supply power to the fuel cell body.

In this embodiment, the second preset electric quantity threshold is set to 15% of the total capacity of the starting battery, that is, if the remaining electric quantity of the current starting battery is lower than 15%, it is determined that the electric quantity is low, and other starting batteries need to be switched to replace the electric quantity.

S52: if the second starting battery exists, after the discharging circuit of the first starting battery is disconnected and the charging circuit of the first starting battery is connected, the discharging circuit of the second starting battery is connected and the charging circuit of the second starting battery is disconnected;

specifically, in the starting process of the fuel cell, all the starting cells alternately supply power to the starting of the fuel cell body in principle, and if the electric quantity of the starting cell supplying power to the fuel cell body is too low before the fuel cell body is completely started, other starting cells with high electric quantity are switched to replace the starting cells until the fuel cell is completely started;

furthermore, when the discharging circuit of the second starting battery is conducted, if the second starting battery is originally in a charging state, the charging circuit of the second starting battery is disconnected; if the second starting battery is originally in the idle state, the discharging circuit of the second starting battery is directly conducted.

S521: if the residual electric quantity of a plurality of starting batteries in the rest starting batteries is larger than that of the first starting battery, the starting battery with the highest residual electric quantity is used as a second starting battery;

S53: and if the second starting battery does not exist, keeping the discharge circuit of the first starting battery conducted.

Specifically, if the second starting battery does not exist, it indicates that the remaining power of the remaining starting batteries is lower at the current time, the first starting battery is firstly maintained to supply power to the fuel cell body, and then the remaining power of the remaining starting batteries is detected again according to a certain rule to serve as the second starting battery. The rule may be predefined, for example, after a certain time, or when the remaining power of the current first starting battery further decreases to a certain preset value, or after the remaining power of the current first starting battery further decreases by a certain power.

S6：

S61: after the fuel cell body is started and normally outputs, disconnecting all discharge circuits of the starting cell;

specifically, after the fuel cell is fully started, i.e., no external power is required, the discharge circuits of all the starting cells are disconnected. At the moment, the power supply of the starting battery to the user terminal is also cut off, and the fuel cell body supplies power to the user terminal.

S62: respectively judging whether the residual electric quantity of all the starting batteries is smaller than a first preset threshold value;

s63: according to the judgment result, conducting a charging circuit of the starting battery with the residual electric quantity smaller than a first preset electric quantity threshold value;

Specifically, after the fuel cell is completely started, the starting battery with the residual capacity less than the first preset capacity threshold is charged according to the residual capacity of each starting battery, that is, the corresponding charging circuit is turned on.

At the moment, if the photovoltaic power generation device is normal, the corresponding starting battery is charged through the photovoltaic power generation device; and if the photovoltaic power generation device cannot be used, the starting battery corresponding to the fuel cell body is used for charging until the municipal power grid is recovered.

Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that features described in different dependent claims and herein may be combined in ways different from those described in the original claims. It is also to be understood that features described in connection with individual embodiments may be used in other described embodiments.