Method for controlling a charging station system consisting of at least two charging stations and charging station for use in a charging station system

Abstract

The invention relates to a method for controlling a charging station system composed of at least two charging stations, which are each equipped with at least one solid oxide fuel cell and a high-voltage battery that is electrically connectable or electrically connected to the solid oxide fuel cell. The charging stations are set up to provide an electrical charging current at an interface for coupling a consumer electrically operated battery via a converter. This includes the following steps: checking the state of charge of the high-voltage battery of a first charging station, by means of which the electrical energy for charging a consumer is provided via the interface; charging the high-voltage battery of the first charging station and, if necessary, the consumer by means of the current-generating operation of the solid oxide fuel cell of the first charging station when the state of charge of the high-voltage battery of the first charging station falls below a first limit value; and charging the high-voltage battery of the first charging station by means of the current provided by a second charging station when the state of charge of the high-voltage battery falls below a second limit value that lies below the first limit value.

Description

TECHNICAL FIELD

[0001] The invention relates to a method for controlling a charging station system consisting of at least two charging stations, which are each equipped with at least one solid oxide fuel cell and a high-voltage battery that is electrically connectable or electrically connected to the solid oxide fuel cell, wherein the charging stations are set up to provide an electrical charging current at an interface for coupling a consumer electrically operated battery via a converter, the method comprising the following steps:

[0002] - checking the state of charge of the high-voltage battery of the first charging station, by means of which the electrical energy for charging the consumer is provided via the interface,

[0003] - charging the high-voltage battery of the first charging station and, if necessary, the consumer by means of the current generated by the operation of the solid oxide fuel cell of the first charging station when the state of charge of the high-voltage battery of the first charging station falls below a first limit value, and

[0004] - charging the high-voltage battery of the first charging station by means of the current provided by the second charging station when the state of charge of the high-voltage battery falls below a second limit value that lies below the first limit value. BACKGROUND

[0005] Fuel cells are used to provide electrical energy in a chemical reaction between a hydrogen-containing fuel and an oxygen-containing oxidizing agent, usually air. In a solid oxide fuel cell (English: Solid Oxide Fuel Cell), the electrolyte layer here consists of a solid material, for example ceramic yttrium-doped zirconium dioxide, which is able to conduct oxygen ions, while electrons are not conducted. The electrolyte layer is accommodated between two electrode layers, namely a cathode layer, which is supplied with air, and an anode layer, which is supplied with fuel, which can be formed by H2, CO, CH4 or similar hydrocarbons. If air is guided through the cathode layer to the electrolyte layer, the oxygen receives two electrons and the formed oxygen ions O 2- move through the electrolyte layer to the anode layer, where the oxygen ions react with the fuel to form water and CO2. The following reaction takes place on the cathode side: 1 / 2O2+ 2e - → 2O 2- (reduction / electron reception). The following reactions take place at the anode: H2+ O 2- → H2O + 2e - and CO + O 2- → CO2+ 2e - (oxidation / electron emission).

[0006] Solid oxide fuel cells require a high temperature of more than 700°C, in which the solid oxide fuel cell is operated.

[0007] With the increasing number of fuel cell vehicles, there is an increasing need for charging columns at strategically advantageous locations, such as supermarket parking lots. However, the power grid was not designed for this kind of power. Alternatively, there is the possibility of arranging a solid oxide fuel cell for generating electric current in the charging column, the fuel of which can be provided via the gas grid, in particular the gas grid for natural gas, since the capacity of the gas grid is sufficient for energy transport. This solid oxide fuel cell generates a large amount of waste heat.

[0008] A charging station with a battery charger and a control method which minimizes the cycle of switching on and off of a fuel cell during charging of a plurality of electric vehicles is described in KR 100 963 529 B1. CN 104 393 626 A1 discloses a charging station operated with a solid oxide fuel cell. A system for supplying an electrical load consisting of a plurality of fuel cells connected in parallel is known from JP 2005 019 182 A. SUMMARY

[0009] It is an object of the present application to provide a method for minimizing the energy loss due to heating of a solid oxide fuel cell in a charging station by interconnecting a plurality of charging columns. It is furthermore an object of the present application to specify a charging column of a charging column system for carrying out the method.

[0010] This object is achieved by the method according to the present application and the charging column according to the present application. The present application has a number of advantageous design variants with suitable improvements.

[0011] The method according to the present application is characterized in that at least two charging columns with a solid oxide fuel cell are used in a charging column system, wherein the solid oxide fuel cell is electrically connectable or electrically connected with a high-voltage battery, and wherein the state of charge of a first charging column is checked, the high-voltage battery of the first charging column is charged as soon as the state of charge falls below a first limit value, and the high-voltage battery of the first charging column is charged by means of a second charging column when the state of charge of the high-voltage battery falls below a second limit value. By means of the intelligent electrical interconnection of a plurality of such charging columns, it is possible to minimize the energy loss due to frequent heating of the high-temperature fuel cell formed as a solid oxide fuel cell in the respective charging column, thereby increasing the efficiency of the fuel cell used.

[0012] It is furthermore advantageous if the electric current provided by the second charging column is generated by the solid oxide fuel cell of the second charging column. As a prerequisite for this, it can be provided that the temperature of the solid oxide fuel cell of the second charging column has a minimum temperature, wherein the charging is otherwise also carried out via the high-voltage battery of the second charging column. Thereby, the charging energy of the charging columns is increased in the case of unequal distribution of use, since the solid oxide fuel cell does not have to be additionally heated.

[0013] It is furthermore advantageous if more than two charging columns are present in the charging column system, and the high-voltage battery of the first charging column is supplied with the current of the solid oxide fuel cell of such a charging column in which at least one solid oxide fuel cell is in operation and has a preset minimum temperature. Thereby, a solid oxide fuel cell which is already "warmer" can be selected, whereby losses for heating a "colder" solid oxide fuel cell are avoided.

[0014] It is furthermore advantageous if more than two charging columns are present in the charging column system, the high-voltage battery of the first charging column is charged in the resting state completely by the solid oxide fuel cell of the first charging column, subsequently such a charging column of the charging column system is identified whose high-voltage battery has the lowest state of charge, and this high-voltage battery is charged with the current generated by the at least one solid oxide fuel cell of the first charging column, whereby the entire charging column system can be used more economically.

[0015] It is furthermore meaningful if, when it is determined that the high-voltage batteries of all further charging columns of the charging column system have a state of charge which has reached or exceeded a first limit value, the at least one solid oxide fuel cell of the first charging column is switched off, whereby an uneven state of charge is compensated.

[0016] It is furthermore advantageous if, in the case of a state of charge below the first limit value in the first charging column, such a charging column is identified whose high-voltage battery subsequently reaches or exceeds the first limit value, and the electrical power of the solid oxide fuel cell of this charging column is used to recharge the first charging column. It is however also possible that this charging column is first charged completely, and subsequently the first charging column with the lower state of charge is charged. A good thermal utilization of the solid oxide fuel cells is thereby possible, since start-up losses and heating losses are minimized.

[0017] Alternatively, the possibility exists that, in the case of a state of charge below the first limit value in the first charging column and in the case of the solid oxide fuel cells of all further charging columns being switched off, such a charging column is identified whose solid oxide fuel cell is the warmest, after which this solid oxide fuel cell is first switched on and used to recharge the high-voltage battery of the first charging column. By using the warmest solid oxide fuel cell to recharge the high-voltage battery, frequent heating of all solid oxide fuel cells can be avoided, which is characterized by a longer service life and lower investment costs of the charging column system.

[0018] It is furthermore meaningful that the first limit value lies in the range of 60% to 80% of the total battery capacity. In this way, it is thus not necessary to immediately or permanently recharge the charging column. This can be advantageous due to the heating energy required for the solid oxide fuel cell, since the solid oxide fuel cell only causes (delayed) recharging when it has an efficiency-optimized operating temperature.

[0019] It is furthermore advantageous for the operationally reliable charging of the consumer that the second limit value lies in the range of 40% to 50% of the total battery capacity. For safety reasons and to avoid deep discharging of the high-voltage battery, it is meaningful to preset a third limit value which lies in the range of 15% to 20% of the total battery capacity.

[0020] According to the invention, it is also proposed that a charging column comprises a high-voltage battery and at least one solid oxide fuel cell which is connected or connectable via a direct-voltage converter, wherein the high-voltage battery and / or the solid oxide fuel cell is connected or connectable via the converter with an interface in order to couple a consumer which is electrically operated by the battery and to recharge it. The charging column is characterized in particular in that there is a further electrical interface on the battery side of the direct-voltage converter for electrically linking a further charging column, a first switch is inserted in the connection which extends to the further electrical interface for electrically linking or electrically disconnecting the further charging column, and a second switch is present on the battery side for electrically linking or electrically disconnecting the high-voltage battery from the connection which extends to the further electrical interface. The following advantages arise thereby: The high-voltage battery of the other charging column can be charged using a fuel cell which is still active or has the lowest temperature, whereby heating losses are reduced. The advantages, design solutions and effects explained in connection with the method according to the invention also apply to the charging column according to the invention.

[0021] The features and combinations of features mentioned in the description above and the features and combinations of features mentioned in the description of the figures below and / or shown in the figures alone can be used not only in the respective combination mentioned, but also in other combinations or on their own, without departing from the scope of the present invention. Thus, embodiments which are not explicitly shown or explained in the figures, but which are known or can be derived from the explained embodiments by means of the individual features combinations, are also to be considered as included and disclosed by the present invention. BRIEF DESCRIPTION OF DRAWINGS

[0022] Further advantages, features and details of the present invention can be derived from the following description of preferred embodiments and in accordance with the figures. Therein:

[0023] Figure 1 a schematic operation of a charging column system for carrying out the method according to the invention is shown,

[0024] Figure 2a schematic view of a charging column for a charging column system is shown, and

[0025] Figure 3 a schematic view of a charging column system formed by a plurality of charging columns is shown. DETAILED DESCRIPTION

[0026] Figure 1 A schematic flow of a method for controlling a charging column system 10 is shown, wherein first the state of charge of the high voltage battery 12 of the first charging column 8 is checked (S100). When the state of charge of the high voltage battery 12 of the first charging column 8 falls below a first limit value, for example in a range of 60% to 80% of the total battery capacity (S200), the high voltage battery 12 is charged by the solid oxide fuel cell 1 of the first charging column 8 (S300). If necessary, also the battery of the consumer 13 coupled with the first charging column 8 is charged. Alternatively, in case the high voltage battery 12 of the first charging column 8 falls below the first limit value, it can be checked whether the further high voltage batteries of the other charging columns are, if necessary, fully or almost fully charged, and whether there is a solid oxide fuel cell of one of the other charging columns which is still "hot" and thus able to cause a recharge for the first column with better efficiency.

[0027] When the state of charge of the high voltage battery 12 falls below a second limit value, for example in a range of 40% to 50% of the total battery capacity (S400), the high voltage battery 12 of the first charging column 8 is charged by means of a current provided by the second charging column 9 (S500). The provided current is provided by the solid oxide fuel cell 2 of the second charging column 9. When the state of charge of the high voltage battery 12 falls below a third limit value, for example in a range of 15% to 20% of the total battery capacity (S600), the high voltage battery 12 of the first charging column 8 is charged by means of solid oxide fuel cells of a plurality of other charging columns (S700).

[0028] Figure 2A schematic diagram of a first charging column 8 for a motor vehicle 13, which can be operated electrically with a battery, is shown, wherein hybrid vehicles are also included in this definition. All further charging columns of the charging column system 10 are preferably of the same construction. The charging column 8 contains a solid oxide fuel cell 1, which generates an electric current using a fuel 14, for example natural gas provided from a natural gas network, for charging a high-voltage battery 12 and / or a battery of a consumer 13, for example an electric motor vehicle. In the charging column 8, the high-voltage battery 12 is electrically connected to the solid oxide fuel cell 1 via a direct-current voltage converter 18, wherein the high-voltage battery 12 and / or the solid oxide fuel cell 1 are / is connected or connectable to an interface 4 via a converter 3. On the battery side of the direct-current voltage converter 18, a further electrical interface 5 is present for electrically linking a further charging column 9 of the charging column system 10, wherein a first switch 6 is inserted in the connection running to the further electrical interface 5 for electrically linking or electrically disconnecting the further charging column 9. Furthermore, a second switch 7 is present on the battery side for electrically linking or electrically disconnecting the high-voltage battery 12 from the connection running to the further electrical interface 5 in order to selectively electrically link the high-voltage battery to the further second charging column 9 or its own solid oxide fuel cell 1.

[0029] Figure 3 A schematic construction of the charging column system 10 is shown. When the state of charge of the high-voltage battery 12 of the first charging column 8 falls below a first limit value, the high-voltage battery 12 is charged by the solid oxide fuel cell 1 of the first charging column 8. If the state of charge of the high-voltage battery 12 of the first charging column 8 falls below a second limit value, which lies below the first limit value, the high-voltage battery 12 of the first charging column 8 is charged with electric current by means of the solid oxide fuel cell 2 of the second charging column 9. Here, the first charging column 8 is electrically supplied by a charging column in which at least one solid oxide fuel cell 2 is in operation and / or has a preset minimum temperature, so that heating losses can be avoided.

[0030] List of reference signs

[0031] 1 solid oxide fuel cell

[0032] 2 second solid oxide fuel cell

[0033] 3 converter (DC / DC converter)

[0034] 4 first interface

[0035] 5 second interface

[0036] 6 first switch

[0037] 7 second switch

[0038] 8 first charging column

[0039] 9 second charging column

[0040] 10 charging column system

[0041] 11 hot press

[0042] 12 high-voltage battery

[0043] 13 motor vehicle

[0044] 14 fuel / natural gas

[0045] 15 air

[0046] 16 charging current

[0047] 17 thermal insulation

[0048] 18 direct current voltage converter (DC / DC converter).

Claims

1. A method for controlling a charging pile system (10) consisting of at least two charging piles (8, 9), each of which is equipped with at least one solid oxide fuel cell (1) and a high-voltage battery (12) electrically connectable to the solid oxide fuel cell (1), wherein: The charging station (8, 9) is configured to provide an electrical charging current (16) via a converter (3) at an interface (4) for connecting a battery-electrically operated consumer. The method comprises the following steps: - checking the charge state of a high-voltage battery (12) of a first charging station (8), from which electrical energy for charging the consumer is provided via the interface (4), - when the state of charge of the high-voltage battery (12) of the first charging post (8) drops below a first limit value, charging the high-voltage battery (12) of the first charging post (8) by operating the solid oxide fuel cell (1) of the first charging post (8) to generate current, and - When the state of charge of the high-voltage battery (12) falls below a second limit value which is below the first limit value, the high-voltage battery (12) of the first charging post (8) is charged by means of a current provided by a second charging post (9), wherein the current provided by the second charging post (9) is generated by at least one solid oxide fuel cell of the second charging post (9).

2. The method according to claim 1, characterized in that In the charging pile system (10), more than two charging piles are present, and the high-voltage battery (12) of the first charging pile (8) is supplied with current from the solid oxide fuel cells of such charging piles, in which at least one solid oxide fuel cell is in operation and has a predetermined minimum temperature.

3. The method according to any one of claims 1 to 2, characterized in that In the charging pile system (10), there are more than two charging piles, and in a stationary state, the high-voltage battery (12) of the first charging pile (8) is charged entirely by the solid oxide fuel cell (1) of the first charging pile (8), and then such a charging pile of the charging pile system (10) is identified, whose high-voltage battery has the lowest charge state, and the high-voltage battery is charged using the current generated by the at least one solid oxide fuel cell of the first charging pile (8).

4. The method according to any one of claims 1 to 2, characterized in that If it is determined that the high-voltage batteries of all other charging posts of the charging post system (10) have a state of charge that has reached or exceeded the first limit value, at least one solid oxide fuel cell (1) of the first charging post (8) is switched off.

5. The method according to any one of claims 1 to 2, characterized in that In the case of falling below the first limit value in the first charging station (8), a charging station whose high-voltage battery subsequently reaches or exceeds the first limit value is identified and the electrical power of the solid oxide fuel cell of the charging station is used for recharging the first charging station (8).

6. The method according to any one of claims 1 to 2, characterized in that If the first limit value is fallen below in the first charging station (8) and the solid oxide fuel cells of all other charging stations are switched off, the charging station whose solid oxide fuel cell is the hottest is identified, after which the solid oxide fuel cell is switched on first and used to recharge the high-voltage battery of the first charging station.

7. The method according to any one of claims 1 to 2, characterized in that The first limit value is within a range of 60% to 80% of the total battery capacity.

8. The method according to any one of claims 1 to 2, characterized in that The second limit value is within a range of 40% to 50% of the total battery capacity.

9. The method according to any one of claims 1 to 2, characterized in that The method further comprises the steps of: When the state of charge of the high-voltage battery (12) of the first charging post (8) falls below a first limit value, the high-voltage battery (12) of the first charging post (8) and the consumer are charged by the current-generating operation of the solid oxide fuel cell (1) of the first charging post (8).

10. A charging post for use in a charging post system (10) for setting up a charging post system for carrying out the method according to any one of claims 1 to 9, comprising a high-voltage battery (12) and at least one solid oxide fuel cell (1) connectable via a DC voltage converter (3), wherein: The high-voltage battery (12) and / or the solid oxide fuel cell (1) are connectable to an interface (4) via a converter (3) in order to connect and recharge battery-electrically operated consumers. It is characterized in that there is an additional electrical interface (5) on the battery side of the DC voltage converter (3) for electrically connecting to another charging pile, a first switch (6) is connected in the connection extending to the additional electrical interface (5) for electrically connecting or disconnecting the additional charging pile, and a second switch (7) is present on the battery side for electrically connecting or disconnecting the high-voltage battery (12) to the connection extending to the additional electrical interface (5).

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