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DE-102014108601-B4 - Method for connecting multiple battery units to a two-pole input of a bidirectional battery converter, as well as bidirectional battery converters and photovoltaic inverters

DE102014108601B4DE 102014108601 B4DE102014108601 B4DE 102014108601B4DE-102014108601-B4

Abstract

Method for connecting several battery units (11 to 13) in parallel or in series to a two-pole input (8) of a bidirectional battery converter (9) having measuring devices, comprising: - Recording a relevant variable parameter of the individual battery units (11 to 13) with the measuring devices; and - Matching the relevant parameter of the individual battery units (11 to 13) with the battery converter (9); characterized in that, - that the battery units (11 to 13) are individually connected to the input (8) for detection and adjustment; and - that the battery units (11 to 13) are connected together to the input (8) only after their relevant parameters have been adjusted, in order to operate them with the battery converter (9) as a closed battery bank (5).

Inventors

  • Aleksandra-Sasa Bukvic-Schäfer
  • Florian Ellerkamp
  • Klaus Rigbers

Assignees

  • SMA SOLAR TECHNOLOGY AG

Dates

Publication Date
20260513
Application Date
20140618
Priority Date
20130628

Claims (15)

  1. Method for connecting several battery units (11 to 13) in parallel or in series to a two-pole input (8) of a bidirectional battery converter (9) having measuring devices, comprising: - acquiring a relevant variable parameter of the individual battery units (11 to 13) with the measuring devices; and - matching the relevant parameter of the individual battery units (11 to 13) with the battery converter (9); characterized in that the battery units (11 to 13) are individually connected to the input (8) for detection and matching; and that the battery units (11 to 13) are connected together to the input (8) only after their relevant parameter has been matched, in order to operate them with the battery converter (9) as a closed battery bank (5).
  2. Procedure according to Claim 1 , characterized in that, in at least one of the battery units (11 to 13) whose relevant parameter is changed, electrical power is supplied via the battery converter (9) from an AC network (3) to which the battery converter (9) is connected on the output side, or from a photovoltaic generator (4) with which the battery converter (9) is connected to a DC/AC converter (2), and/or electrical power is discharged via the battery converter (9) into the AC network (3).
  3. Procedure according to Claim 1 or 2 , characterized in that the battery units (11 to 13) are first individually connected to the input (8) to acquire their relevant parameter, and that then at least the battery units (11 to 13) are secondly individually connected to the input (8) whose relevant parameter is changed to match the battery converter (9).
  4. Procedure according to one of the Claims 1 until 3 , characterized in that the at least one relevant parameter of the battery units (11 to 13) is adjusted to a value which is specified depending on the previously recorded values of the at least one relevant parameter.
  5. Procedure according to Claim 4 , characterized in that the value is specified taking into account at least one predefined criterion, depending on the previously recorded values of at least one relevant parameter.
  6. Procedure according to Claim 5 , characterized in that at least one criterion is selected from: - minimizing the duration of the process; - minimizing the individual connection operations to the input (8) during the process; - minimizing energy losses through the process; - minimizing the consumption of energy from an AC network (3) to which the battery converter (9) is connected on the output side, and/or of electrical energy supplied by a generator which is connected to an AC network (3) together with the battery converter (9); and - maximizing the self-consumption of electrical energy supplied by a generator which is connected to an AC network (3) together with the battery converter (9).
  7. Method according to one of the preceding claims, characterized in that an error message is issued if at least one detected parameter of at least one battery unit (11 to 13) is incompatible with at least one detected parameter of at least one other battery unit (11 to 13).
  8. Procedure according to one of the Claims 1 until 7 , characterized in that , for connecting the battery units (11 to 13) in parallel, the output voltage (U Batt ) and optionally the state of charge and/or the state of aging of the battery units (11 to 13) are detected and at least the output voltage (U Batt ) is adjusted.
  9. Procedure according to one of the Claims 1 until 7 , characterized in that , for connecting the battery units (11 to 13) in series, the state of charge and optionally the output voltage (U Batt ) and/or the state of aging of the battery units (11 to 13) are detected and at least the state of charge is equalized.
  10. Procedure according to one of the Claims 1 until 9 , characterized in that the individual connection of the battery units (11 to 13) to the input (8) is carried out manually under guidance by a control of the battery converter (9).
  11. Procedure according to one of the Claims 1 until 9 , characterized in that the individual connection of the battery units (11 to 13) to the input (8) is carried out via a separate multiplexer device, which is controlled by a control unit of the battery converter (9).
  12. Procedure according to one of the Claims 1 until 11 , characterized in that when replacing an old battery unit (11 to 13) with a new battery unit (11 to 13), the new battery unit (11 to 13) is connected individually to the input (8), that the at least one relevant parameter of the newer battery unit (11 to 13) is recorded and adapted to the value of the at least one relevant parameter of the other old battery units (11 to 13), and that the new battery unit (11 to 13) is then connected to the input (8) together with the other old battery units (11 to 13).
  13. Bidirectional battery converter (9) to which several battery units (11 to 13) can be connected in parallel or in series on the input side, comprising - a two-pole input (8); - measuring devices for at least one relevant parameter of the battery units (11 to 13) connected to the input (8); and - a control unit which has a selectable operating mode for carrying out the method according to one of the preceding claims.
  14. Battery converter (9) after Claim 13 , characterized in that the battery converter (9) is a DC/DC converter which, together with a photovoltaic generator (4), is connected to a DC intermediate circuit of a DC/AC converter (2) which can be connected to an AC network (3).
  15. Photovoltaic inverter (1) with a battery converter (9) according Claim 14 , with a further two-pole input (19) for a photovoltaic generator (4) and with a DC/AC converter (2) for output-side connection to an AC network (3), wherein the battery converter (9) is a DC/DC converter which is connected together with the photovoltaic generator (4) to a DC intermediate circuit (7) of the DC/AC converter (2).

Description

TECHNICAL AREA OF INVENTION The present invention relates to a method for connecting several battery units in parallel or in series to a two-pole input of a bidirectional battery converter comprising measuring devices, comprising the steps of the preamble of independent claim 1. The present invention further relates to a bidirectional battery converter for connecting several battery units in parallel or in series, having a two-pole input, measuring devices for at least one relevant parameter of the battery units connected to the input, and a controller comprising an operating mode for carrying out the method. The method according to the invention also relates to a photovoltaic inverter with such a battery converter. STATE OF THE ART From the WO 02 / 039 563 A1 A battery charging device and a method for charging batteries using a power supply module are known. In this system, a battery comprises several battery blocks connected in series. The individual battery blocks are charged sequentially for a specific duration once per charging cycle, and the charging cycle is repeated until the individual battery blocks reach a defined state of charge or the power supply is interrupted. The known battery charging device is particularly suitable for charging batteries for electric vehicles. In one embodiment of the known method, switching from one battery block to the next during a charging cycle is automatic, using a switch. This switching can be electronic and/or electronically controlled. In another embodiment, a single battery block is charged for a duration of 30 to 300 seconds per charging cycle. This has the advantage, among others, that if charging is prematurely terminated, the battery blocks do not exhibit excessively large differences in charge. From the DE 10 2005 045 107 A1 A charging method for extending the service life of batteries and a device for carrying it out are known. In this charging method, in addition to a main charging process of a battery with at least two series-connected battery cells, an auxiliary charging process is performed. This auxiliary process comprises the steps of selectively charging at least one selected battery cell beyond the normal state of charge of the battery and equalizing the state of charge of the selected battery to the normal state of charge of the battery. Thus, to extend the service life of batteries, it is intended to select one battery cell within a series connection of battery cells, fully charge it, and then, after full charging, equalize the state of charge of this selected battery cell with the state of charge of the other battery cells. The selective charging is carried out using an auxiliary charge controller. The equalization of the state of charge is performed dissipatively. To maintain an overview of the states of the battery cells and the entire battery at all times, at least one battery parameter is continuously monitored. From the DE 20 2006 003 587 U1 A battery charge equalization circuit with an electrical charge source is known. At least two batteries are connected to the electrical charge source in a parallel circuit. A PTC thermistor is provided as a defined current limiter, through which the positive terminals of two consecutive batteries are connected. Using the PTC thermistor, automatic battery charge equalization with self-adjusting current limiting is achieved in a simple manner. At the same time, overloading of the electrical charge source is prevented. From the DE 10 2010 011 279 A1 A method for charge balancing in a battery system and a battery system with a charge balancing circuit are known. Charge balancing takes place between two cells of a cell array in the battery system, each with a resting voltage. In a first state, the charge balancing circuit charges an intermediate energy storage device. In a second state, the intermediate energy storage device charges one of the two cells with a charging voltage. This charging voltage is higher than either of the cells' resting voltages. In particular, charge balancing can be carried out between two cells of a cell array. That is, a first cell supplies the energy, which is then transferred to the second cell. Charge balancing can also occur in conjunction with voltage equalization. From the DE 10 2009 027 685 A1 A solar-assisted battery charging device, particularly for a hybrid and/or electric vehicle, is known. The battery charging device has a control device with a connection for receiving a charging voltage supplied by a solar module. The control device selectively switches the charging voltage supplied by the solar module to one or more of the cell blocks of a high-voltage storage system, which is located in several The battery is divided into several cell blocks, each with a lower nominal voltage than the entire high-voltage battery. A measuring device measures one or more parameters of these cell blocks. Based on the measured parameter(s), a control unit selectively switches the chargin