DE102018122564A1 - Electrical energy storage system - Google Patents

Abstract

The invention relates to an electrical energy storage system (11), comprising • a first rechargeable battery (19) with a first nominal voltage; • a bidirectional DC voltage converter (21) with a low voltage side and a high voltage side; • a current distributor (22) to the electrical consumer ( 13, 14, 17, 18) can be coupled: • a diagnostic device for the SOH determination of the first battery (19); wherein • the first battery (19) is coupled to the current distributor (22) • the DC voltage converter (21) is coupled with its high-voltage side to the current distributor (22) • the diagnostic device is connected to the first battery (19) and indirectly or directly the DC-DC converter (21) is coupled, • wherein the diagnostic device is designed such that a current component controls such that this current component generates an AC voltage on the high-voltage side of the DC-DC converter (21), and on the first battery (19) the current strength and the phase The task of creating an electrical energy storage system that enables SOH determination with little effort and cost is achieved in that the DC-DC converter (21) is coupled with its high-voltage side to the power distributor (22) in such a way that the high-voltage side is parallel to the first battery (19).

Description

The invention relates to an electrical energy storage system with the features of the preamble of patent claim 1.

An electric car is known to have a traction battery with a typical nominal voltage between 300 and 400 V and a battery management system that monitors and regulates the traction battery. The battery management system determines the health status of the traction battery; the state of health is also referred to as state-of-health - abbreviated to SOH. This SOH determination can be based on impedance spectroscopy. For this purpose, the known battery management system has a frequency generator which generates an - usually sinusoidal - alternating current and impresses it on the current through the traction battery. In response to this, the traction battery generates an AC voltage, which is recorded and evaluated by the battery management system in order to calculate the impedance, which is then included in the calculation of the aging or the SOH.

The equipment required for this known SOH determination is expensive, large, and heavy.

From the generic US 2014 0 125 284 A1 an energy storage system is known which has a battery pack, a bus to which electrical loads are coupled, and a controller. The battery pack has a plurality of battery pack modules, each of which has an accumulator cell and a bidirectional DC voltage converter with a low-voltage side and a high-voltage side. The battery cells have the same nominal voltage. Each DC-DC converter is coupled with its low-voltage side to the respective battery cell. The high voltage sides are connected in series. This series connection is coupled to the bus. Each accumulator cell is thus coupled to the bus via the respective direct voltage converter and via the remaining direct voltage converters; in addition, each high-voltage side is coupled to the bus via the remaining high-voltage sides. The controller is coupled to the accumulator cells and the DC voltage converter and is designed such that it determines the SOH of each accumulator cell. This SOH determination is carried out on the basis of impedance spectroscopy, in that the controller controls the respective DC-DC converter in such a way that a sinusoidal ripple voltage is superimposed on the DC voltage on the respective high-voltage side, and the voltage and current strength caused thereby are detected and evaluated on the respective accumulator cell.

US 2006 0 170 397 A1 describes a battery health monitoring system that includes a battery health monitor coupled to the poles of the battery and a remote monitoring station that cooperate to monitor battery health. The battery health monitor stimulates the battery, detects the AC voltage generated by this excitation at the battery poles and sends a corresponding signal to the monitoring station. The monitoring station uses this signal to determine the SOH of the battery on the basis of electrochemical impedance spectroscopy. The battery health monitor has a controller and a voltage controlled current source coupled to the poles of the battery. The controller controls the power source so that it generates an alternating current, detects the alternating voltage generated by the alternating current at the poles, generates the signal and sends it to the monitoring station.

The invention is based on the object of providing an electrical energy storage system which enables SOH determination with little effort and cost.

The object on which the invention is based is achieved by an electrical energy storage system having the features of patent claim 1. Advantageous embodiments of the invention are described in the dependent claims.

• • eine erste wiederaufladbare Batterie mit einer ersten Nennspannung;
• • einen bidirektionalen Gleichspannungswandler mit einer Niederspannungsseite und ener Hochspannungsseite;
• • einen Stromverteiler, an den elektrische Verbraucher gekoppelt werden können oder gekoppelt sind;
• • eine Diagnoseeinrichtung für die SOH-Bestimmung der ersten Batterie;

wobei

• • die erste Batterie an den Stromverteiler gekoppelt ist;
• • der Gleichspannungswandler mit seiner Hochspannungsseite an den Stromverteiler gekoppelt ist;
• • die Diagnoseeinrichtung an die erste Batterie und mittelbar oder unmittelbar an den Gleichspannungswandler gekoppelt ist;
• • der Gleichspannungswandler mit seiner Hochspannungsseite an den Stromverteiler derart gekoppelt ist, dass die Hochspannungsseite parallel zu der ersten Batterie geschaltet ist,
• • wobei Diagnoseeinrichtung derart ausgebildet ist, dass einen Stromanteil derart steuert, so dass dieser Stromanteil eine Wechselspannung an der Hochspannungsseite des Gleichspannungswandlers erzeugt, und an der ersten Batterie die Stromstärke und die Phase ermittelt.

The invention proposes an electrical energy storage system comprising

• • a first rechargeable battery with a first nominal voltage;
• • a bidirectional DC converter with a low voltage side and a high voltage side;
• • a power distributor to which electrical consumers can be coupled or are coupled;
• A diagnostic device for the SOH determination of the first battery;

in which

• • the first battery is coupled to the power distributor;
• • The DC-DC converter is coupled with its high-voltage side to the power distributor;
• • The diagnostic device is coupled to the first battery and indirectly or directly to the DC-DC converter;
• The DC voltage converter is coupled with its high voltage side to the current distributor in such a way that the high voltage side is connected in parallel with the first battery,
• Wherein the diagnostic device is designed such that a current component controls such that this current component generates an AC voltage on the high-voltage side of the DC-DC converter and determines the current strength and the phase on the first battery.

The energy storage system according to the invention is designed and / or suitable in particular for use in an electric vehicle or an electric car or a hybrid electric vehicle or a plug-in hybrid electric vehicle.

The first battery can be designed in any manner as required, for example in such a way that it is a traction battery of an electric vehicle or an electric car or a hybrid electric vehicle or a plug-in hybrid electric vehicle and / or a nominal voltage between 300 and 400 V or 300 V or 320 V or 350 V or 360 V or 400 V. The nominal voltage can be between 260 and 800 V, for example.

The HV battery current in electric vehicles is mainly determined by the driver's request, since this specifies the battery current for traction. In addition, there is another share of electricity that is required for the secondary consumers and that is determined by an energy management system. With the energy storage system according to the invention, this proportionate HV battery current for the secondary consumers or a second battery can be intelligently controlled or manipulated, so that, in addition to the traction current, a total (HV) battery current results, which is an impressed vibration , for example a sine wave or a sinusoidal half wave. This vibration can then be used to determine the SOH of the first battery. By evaluating the voltage response of the HV battery, a statement can be made about the SOH of the first battery. The energy storage system according to the invention enables the impression of (sine) vibrations on an HV battery current for the impedance measurement of an HV battery by means of intelligent auxiliary consumer control. For example, an air conditioning compressor or the like can be controlled in such a way that a corresponding vibration results. These secondary consumers or components can optionally be connected with additional electronics.

Furthermore, there is preferably a second rechargeable battery with a second nominal voltage, the DC voltage converter being coupled with its low voltage side to the second battery. The diagnostic device is preferably designed such that it controls a current component assigned to the second battery in such a way that this current component, together with a traction current, generates an AC voltage on the high-voltage side of the DC-DC converter and determines the current intensity and the phase on the first battery. The second battery can be configured in any manner as required, for example in such a way that it is a starter battery or on-board power supply battery of an electric vehicle or an electric car or a hybrid electric vehicle or a plug-in hybrid electric vehicle and / or a rated voltage between 12 and 48 V or 12 V or 24 V or 48 V.

The first battery is preferably coupled directly to the current distributor and / or the DC voltage converter is coupled directly to the second battery with its low voltage side and / or the DC voltage converter is coupled directly to the current distributor with its high voltage side.

The diagnostic device can be designed in any manner as required, for example in such a way that it carries out the SOH determination cyclically, for example every 8 or 9 or 10 or 11 or 12 operating hours, and / or at the request of a user.

In one embodiment of the invention, it is specified that the diagnostic device is designed such that it carries out the SOH determination on the basis of an impedance spectroscopy or an electrochemical impedance spectroscopy.

The diagnostic device can be designed in any manner as required, for example in such a way that it determines the SOH as shown in US 2014 0 125 284 A1 and / or as described in US 2006 0 170 397 A1 described, can perform.

The diagnostic device is designed such that it controls a current component assigned to the electrical consumers such that this current component, together with a traction current, generates an AC voltage on the high-voltage side of the DC-DC converter, and determines the current strength and the phase on the first battery. The consumer power component can, for example, be assigned to an air conditioning compressor or PTC heater.

• • den Gleichspannungswandler derart ansteuert, dass dieser an seiner Hochspannungsseite eine Wechselspannung erzeugt, und an der ersten Batterie die Stromstärke und die Phase ermittelt; und / oder
• • den Gleichspannungswandler derart ansteuert, dass dieser an seiner Hochspannungsseite einen Wechselstrom erzeugt, und an der ersten Batterie die Spannung und die Phase ermittelt.

In one embodiment of the invention, it is specified that the diagnostic device is designed such that it is used for SOH determination

• Controls the DC-DC converter in such a way that it generates an AC voltage on its high-voltage side and determines the current strength and the phase on the first battery; and or
• • controls the DC-DC converter in such a way that it generates an AC current on its high-voltage side and determines the voltage and the phase on the first battery.

The diagnostic device can determine the SOH from the time profiles of these AC variables in a known manner, for example.

The AC voltage can be designed in any manner as required, for example in such a way that it has the form of a sinusoidal oscillation or a sinusoidal oscillation and / or a frequency between 10 mHz and 10 kHz. The alternating current can be designed in any manner as required, for example in such a way that it has the form of a sine wave or a half sine wave and / or a frequency between 10 mHz and 10 kHz.

In one embodiment of the invention, it is specified that the energy storage system has a switching device, the switching device connecting the batteries to the consumers that are coupled to the power distributor in a first switching position and disconnecting the batteries from at least one of these consumers in a second switching position; wherein the diagnostic device is designed such that it switches the switching device into the second switching position for SOH determination.

Since, for example, the current distributor in current electric cars usually has an intermediate circuit via which the traction battery is coupled to the electric motor and which has an intermediate circuit capacitor whose capacitance is so large that it would equalize or strongly attenuate the impressed AC voltage or the alternating current, can with this switching device in the second switching position of the consumer "electric motor" separated and this effect of the intermediate circuit can be prevented. As a result, the SOH determination can be carried out reliably. It is possible for the diagnostic device to be coupled to the DC voltage converter directly or via the switching device.

• • die Schalteinrichtung einen Schalter aufweist;
• • der Schalter wenigstens einen der Verbraucher, die an den Stromverteiler gekoppelt sind, mit den Batterien verbindet oder von den Batterien trennt.

In one embodiment of the invention it is specified that

• • the switching device has a switch;
• • The switch connects at least one of the consumers, which are coupled to the power distributor, with the batteries or disconnects from the batteries.

• • die Batterien über eine gemeinsame Minusleitung und eine gemeinsame Plusleitung an den Stromverteiler gekoppelt sind;
• • die Schalteinrichtung einen ersten und einen zweiten Schalter aufweist;
• • der erste Schalter in der Minusleitung und der zweite Schalter in der Plusleitung sitzt.

In one embodiment of the invention it is specified that

• • the batteries are coupled to the power distributor via a common negative line and a common positive line;
• • the switching device has a first and a second switch;
• • The first switch is in the negative line and the second switch is in the positive line.

In one embodiment of the invention, it is specified that at least one of the switches has a contactor and / or a relay and / or a semiconductor switch.

In one embodiment of the invention, it is specified that the energy storage system has an electric motor that is coupled to the power distributor as a consumer, the first battery being a traction battery.

In one embodiment of the invention it is specified that the switching device is designed such that it separates the batteries from the electric motor in the second switching position.

In one embodiment of the invention, it is specified that the energy storage system has an air conditioning compressor which is coupled to the power distributor as a consumer and / or a PTC heater which is coupled to the power distributor as a consumer.

The invention also proposes a vehicle with one of the proposed energy storage systems.

The vehicle can be designed in any manner as required, for example as an electric vehicle or as an electric car or as a hybrid electric vehicle or as a plug-in hybrid electric vehicle.

• 1 eine bevorzugte Ausführungsform eines Elektroautos, das eine erste Ausführungsform eines elektrischen Energiespeichersystems aufweist;
• 2 einen Teil einer zweiten Ausführungsform des Energiespeichersystems.

There are now a multitude of options for designing and developing the energy storage system according to the invention in an advantageous manner. For this purpose, reference may first be made to the claims subordinate to claim 1. A preferred embodiment of the invention may be explained in more detail below with reference to the drawing and the associated description. The drawing shows:

• 1 a preferred embodiment of an electric car having a first embodiment of an electrical energy storage system;
• 2nd part of a second embodiment of the energy storage system.

In 1 is a preferred embodiment of an electric car 10th schematically shown that an electrical energy storage system 11 , a charger 12th , an inverter 13 , an electric motor 14 , a gear 15 , a front axle 16 , an air conditioning compressor 17th and a PTC heater 18th having.

The energy storage system 11 is designed according to a first embodiment and has a first rechargeable battery 19th , a second rechargeable battery 20th , a bidirectional DC converter 21 with a low voltage side and a high voltage side, a power distributor 22 , a diagnostic device (not shown) for the SOH determination of the first battery 19th and a switching device 24th on.

The power distributor 22 shows a minus line (left in 1 ) and a plus line (right in 1 ) and is in a battery section 221 and a consumer section 222 divided. Battery section 221 and consumer section 222 are connected in series.

The charger 12th is on the first battery 19th electrically coupled. The inverter 13 is with its DC voltage side to the consumer section 222 and with its AC side to the electric motor 14 electrically coupled. The electric motor 14 is about the gearbox 15 to the front axle 16 mechanically coupled. The air conditioning compressor 17th and the PTC heater 18th are at the consumer section 222 electrically coupled.

The first battery 19th is an example of a traction battery with a first nominal voltage of 400 V, and the second battery 20th is an example of a starter battery with a second nominal voltage of 12 V. Thus, the second nominal voltage is less than the first nominal voltage. The first battery 19th is on the battery section 221 electrically coupled by the negative pole (below in 1 ) and the positive pole (above in 1 ) of the battery 19th to the negative and positive lines of the power distributor 22 are connected. The DC-DC converter 21 is with its low voltage side to the second battery 20th electrically coupled. The DC-DC converter 21 is parallel to the first battery with its high voltage side 19th to the battery section 221 electrically coupled by the negative pole (below in 1 ) and the positive pole (above in 1 ) of the DC converter 21 to the negative and positive lines of the power distributor 22 are connected.

The switching device 24th is designed according to a first embodiment and has a switch 25th on. The desk 25th is an example of a single-pole switch in the form of a contactor and sits between the battery section 221 and consumer section 222 exemplary in the positive lead of the power distributor 22 . So the switch 25th a current between the battery section 221 and consumer section 222 optionally enable or prevent and accordingly the consumers connected to the power distributor 22 are coupled, namely inverters 13 / Electric motor 14 , Air conditioning compressor 17th and PTC heater 18th , with the batteries 19th , 20th connect or from the batteries 19th , 20th separate; in addition, the switching device 24th a first switch position, in which the batteries 19th , 20th with these consumers 13 , 14 , 17th , 18th connects, and a second switch position, in which they are the batteries 19th , 20th from these consumers 13 , 14 , 17th , 18th separates, ingest.

The diagnostic device is connected to the first battery 19th , to the DC converter 21 and to the switching device 24th coupled in terms of signaling. The diagnostic device is designed such that it is connected to the first battery 19th Determine current and phase and the DC-DC converter 21 can be controlled in such a way that it generates an AC voltage on its high-voltage side. The diagnostic device is also designed such that it is used to determine the SOH, the switching device 24th switches to the second switch position. The diagnostic device is also designed such that it can carry out the SOH determination on the basis of electrochemical impedance spectroscopy.

It is conceivable that in addition to the auxiliary consumers, the DC-DC converter 21 for the 12V battery serves as the unit that imprints the diagnostic profile. So that in addition to the other auxiliary consumers, especially the DC-DC converter 21 is used for the determination of the state, then via the switching device 24th or the switch 25th other components separated.

In 2nd is part of a second embodiment of the energy storage system 11 shown schematically. This embodiment is similar to the first embodiment, so that the differences are explained in more detail below. In this embodiment, the energy storage system 11 a common negative line 26 and a common plus line 27 for the batteries 19th , 20th on through which this to the power distributor 22 (in 2nd not shown), more precisely to the battery section 221 (in 2nd not shown), are electrically coupled. The negative poles of the batteries 19th , 20th are to the in 2nd left end of the minus line 26 connected, the positive poles of the batteries 19th , 20th to the in 2nd left end of the positive lead 27 . This in 2nd right end of the minus line 26 is to the minus line (in 2nd not shown) of the power distributor 22 connected that in 2nd right end of the plus line 27 to the plus line (in 2nd not shown) of the power distributor 22 .

In this embodiment, the switching device 24th formed according to a second embodiment. This embodiment is similar to the first embodiment, so that the differences are explained in more detail below. In this embodiment, the switching device 24th instead of the switch 25th a first and a second switch 28 , 29 on the example of each as the switch 25th The first switch 28 sits in the common negative line 26 between her in 2nd left and right end, the second switch 29 in the common plus line 27 between her in 2nd left and its right end. So the switches 28 , 29 a current between the batteries 19th , 20th and the consumer section 222 either enable or prevent and accordingly the consumer 13 , 14 , 17th , 18th with the batteries 19th , 20th connect or from the batteries 19th , 20th disconnect two poles. In the first switching position of the switching device 24th are the switches 28 , 29 closed, open in the second switch position. Thus, the switching device 24th the batteries in the first switch position 19th , 20th with consumers 13 , 14 , 17th , 18th connect and in the second switch position the batteries 19th , 20th from these consumers 13 , 14 , 17th , 18th disconnect two poles.

Reference list

10th

Electric car

11

Energy storage system

12th

charger

13

Inverter

14

Electric motor

15

transmission

16

Front axle

17th

Air conditioning compressor

18th

PTC heater

19th

first battery

20th

second battery

21

DC converter

22

Power distributor

221/222

Battery section / consumer section

23

Not awarded

24th

Switching device

25th

switch

26

Minus line from 11

27

Plus line from 11

28

first switch

29

second switch

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 20140125284 A1 [0004, 0016]
• US 20060170397 A1 [0005, 0016]

Claims (13)

Electrical energy storage system (11), comprising • a first rechargeable battery (19) with a first nominal voltage; • a bidirectional direct voltage converter (21) with a low voltage side and a high voltage side; • a power distributor (22) to which electrical consumers (13, 14, 17, 18) can be coupled; • a diagnostic device for the SOH determination of the first battery (19); wherein • the first battery (19) is coupled to the power distributor (22); • the DC-DC converter (21) is coupled with its high-voltage side to the current distributor (22); • the diagnostic device is coupled to the first battery (19) and indirectly or directly to the DC-DC converter (21); Wherein the diagnostic device is designed in such a way that a current component controls such that this current component generates an alternating voltage on the high voltage side of the direct voltage converter (21) and determines the current strength and the phase on the first battery (19), characterized in that • the DC voltage converter (21) is coupled with its high voltage side to the current distributor (22) such that the high voltage side is connected in parallel with the first battery (19). Energy storage system (11) according to the preceding claim, characterized in that the diagnostic device is designed such that it performs the SOH determination on the basis of an impedance spectroscopy or an electrochemical impedance spectroscopy. Energy storage system (11) according to the preceding claim, characterized in that a second rechargeable battery (20) with a second nominal voltage is present, the DC-DC converter (21) being coupled with its low-voltage side to the second battery (20), the diagnostic device being such is designed such that it controls a current component assigned to the second battery (20) in such a way that this current component, together with a traction current, generates an alternating voltage on the high voltage side of the direct voltage converter (21), and on the first battery (19) the current intensity and the phase determined. Energy storage system (11) according to one of the preceding claims, characterized in that the second nominal voltage is less than the first nominal voltage. Energy storage system (11) according to one of the preceding claims, characterized in that the diagnostic device is designed such that it controls a current component assigned to the electrical consumers (13, 14, 17, 18) such that this current component together with a traction current produces an AC voltage generated on the high-voltage side of the DC-DC converter (21), and the current and phase are determined on the first battery (19). Energy storage system (11) according to one of the preceding claims, characterized in that the diagnostic device is designed such that it controls the DC-DC converter (21) for SOH determination in such a way that it generates an AC voltage on its high-voltage side, and on the first battery (19 ) determines the current strength and the phase; and / or controls the direct voltage converter (21) in such a way that it generates an alternating current on its high voltage side and determines the voltage and the phase on the first battery (19). Energy storage system (11) according to one of the preceding claims, characterized by a switching device (24); wherein the switching device (24) connects the batteries (19, 20) to the consumers (13, 14, 17, 18) which are coupled to the power distributor (22) in a first switching position and the batteries (19 , 20) from at least one of these consumers (13, 14, 17, 18); the diagnostic device (23) is designed such that it switches the switching device (24) to the second switching position for SOH determination. Energy storage system (11) according to the preceding claim, characterized in that the switching device (24) has a switch (25); the switch (25) connects at least one of the consumers (13, 14, 17, 18), which is coupled to the power distributor (22), with the batteries (19, 20) or separates them from the batteries (19, 20). Energy storage system (11) according to one of the two preceding claims, characterized in that the batteries (19, 20) are coupled to the power distributor (22) via a common minus line (26) and a common plus line (27); the switching device (24) has a first and a second switch (28, 29); the first switch (28) in the negative line (26) and the second switch (29) in the positive line (27). Energy storage system (11) according to one of the three preceding claims, characterized in that at least one of the switches (25, 28, 29) on Contactor and / or a relay and / or a semiconductor switch. Energy storage system (11) according to one of the preceding claims, characterized by an electric motor (14) which is coupled as a consumer (13, 14, 17, 18) to the power distributor (22); the first battery (19) being a traction battery. Energy storage system (11) according to the preceding claim and one of the Claims 4 to 7 , characterized in that the switching device (24) is designed such that it separates the batteries (19, 20) from the electric motor (14) in the second switching position. Vehicle (10) with an energy storage system (11) according to one of the preceding claims.

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