DE102018123552B4 - DEVICE AND METHOD FOR WAKE-UP AN AUTOMOTIVE BATTERY - Google Patents

Abstract

Device for waking up a vehicle battery (1), a battery management system, BMS, and/or an on-board network of a vehicle or at least one component thereof, having:- a device (3) for detecting a quiescent current flowing in at least one area of the BMS or on-board network and for Outputting a voltage characterizing the detected quiescent current, and- a comparator circuit for comparing the voltage with at least one predetermined or definable threshold value, wherein the comparator circuit is designed to emit a wake-up signal when the threshold value is exceeded, the wake-up signal being generated directly by a has a voltage level that can be used by a microcontroller, the device having a device for activating and/or deactivating electronic components of the vehicle electrical system based on the wake-up signal, the device having one or more CMOS circuits, the device having a device (7) for amplifying the voltage characterizing the detected quiescent current, the amplification factor of the device being dimensioned such that a CMOS voltage level of the voltage characterizing the quiescent current is reached; and wherein the device comprises means (8) for rectifying the boosted voltage.

Description

The invention relates to a device and a method for waking up a vehicle battery. According to embodiments of the invention, this relates to devices and methods for waking up or starting a battery management system of a battery with one or more battery modules.

Furthermore, a computer program and a battery management system are specified, which are suitable for carrying out the method.

Battery management systems (BMS) are generally used to monitor and control a battery, in particular a battery based on lithium-ion technology, but also a lead-acid battery. This can be designed to perform safety functions, to keep the state of charge of the individual cells at approximately the same level, and/or to monitor the status of individual cells or cell groups and the like. So far, external wake-up signals have usually been used to wake up the battery management system from a sleep mode. For this purpose, it is necessary for a processor of an additional control unit to be operated permanently, ie also in the sleep mode of the battery management system, and to forward the wake-up signal to the battery management system as required.

For example, the US 2017/0 297 448 A1 a conventional battery level management system for an electric vehicle in a powered down and non-charged period, in which a current output from a low voltage battery of the electric vehicle that is above a threshold can be detected to wake up a control unit connected to the low voltage battery without others Wake up or fully power control units.

the DE 10 2007 008 044 A1 is directed to another conventional tester for a vehicle, the vehicle, and a method for initiating diagnostic communication between the vehicle and the tester. In the means of transport, a central control unit for diagnostic communication is woken up in that the test device draws current from the vehicle electrical system, a current sensor detects this current as exceeding a limit value and emits a wake-up signal via a local bus to the central control unit, which responds is activated upon the wake-up signal so that diagnostic communication is initiated.

the DE 10 2014 201 196 A1 relates to another conventional method for operating a battery management system which is connected to an operating voltage. Switches to an idle state when the operating voltage drops below a switch-off threshold value and switches to an operating state when the operating voltage rises above a switch-on threshold value, the switch-on threshold value being greater than the switch-off threshold value.

More such devices for waking up a battery management system are for example from US 6,489,749 B1 , the U.S. 8,350,529 B2 , the US 2013/0 314 047 A1 , the DE 10 2005 002 679 A1 , the US 2010/0 327 813 A1 and the US 2004/0 119 517 A1 known.

Since these wake-up circuits known from the prior art provide for at least one processor to be operated continuously even in the sleep mode of the battery management system, there is a relatively high power requirement, which is particularly disadvantageous when, for the purpose of saving power, the Battery management system is in sleep mode.

On the basis of this problem, the object of the present invention is to further develop a device and a method for waking up a battery management system of the type mentioned at the outset such that the power consumption during operation of the device can be further reduced.

With regard to the device, the object on which the invention is based is achieved by the subject matter of independent patent claim 1 and with regard to the method by the subject matter of independent patent claim 12, with advantageous developments of the device and the method being specified in the corresponding subclaims.

The invention also relates to a system according to the independent patent claim 14 and a computer program according to the independent patent claim 15.

Accordingly, the invention relates in particular to a device for waking up a battery management system and/or an on-board network of a vehicle or at least one component thereof, the device having a device for detecting a quiescent current flowing in at least one area of the on-board network or the battery management system and for outputting a dem detect Quiescent current characterizing voltage and a comparator circuit for comparing the voltage with at least has a predefined or definable threshold value. According to the invention, the comparator circuit is designed in particular to emit a wake-up signal when the predefined or definable threshold value is exceeded, the wake-up signal preferably having a voltage level that can be used directly by a microcontroller of the device or of the battery management system.

Any sensor system that is designed to detect a quiescent current, i. H. a relatively small current, to be detected effectively. This sensor system has at least one corresponding sensor, preferably a shunt. Of course, however, other embodiments for detecting the quiescent current are also possible.

Furthermore, the term "on-board network" used here should be understood to mean all of the electronic components in a vehicle, such as a two-wheeler, automobile, aircraft, ship or train, which are to be supplied with electrical energy via a battery of the vehicle when the vehicle is in operation. This includes in particular 12-volt vehicle electrical systems, which require the power consumption in vehicles (automobiles) for their comfort system. In addition, the term “on-board power supply” is of course also to be understood as meaning other on-board power supplies, in particular 14 volt/42 volt on-board power supplies and 48 volt on-board power supplies, as well as on-board power supplies with other voltage levels.

The term “battery management system” used here is to be understood as meaning an electronic circuit which is used to monitor and control an arrangement of rechargeable accumulator cells in a rechargeable battery. Battery management systems of the type considered here are used, for example, to identify the state of charge. Of course, the term "battery management system" also includes other more complex systems with data interfaces and corresponding power electronics.

A “wake-up signal” is to be understood here as a signal which is used directly or indirectly by the battery management system in order to switch its controller, in particular a microcontroller and/or the associated vehicle electrical system, from a “sleep state” to an operating state.

The solution according to the invention is characterized in particular by the fact that the wake-up device works without an additional control unit, which thus--in comparison to the solutions discussed at the outset and known from the prior art--drastically reduces the power requirement. According to embodiments of the solution according to the invention, the device for detecting a quiescent current is used to detect the quiescent current to be flowing in at least one area of the battery management system (or possibly in an area of the vehicle electrical system) and a voltage signal characterizing this is output, which is processed by the comparator circuit with at least one predetermined threshold is compared. The comparator circuit then emits a corresponding wake-up signal as soon as it is detected that the voltage signal output by the device for detecting a quiescent current exceeds the corresponding threshold value.

The device according to the invention has a device for activating and/or deactivating electronic components of the vehicle electrical system based on the wake-up signal, with the device preferably having one or more CMOS circuits. Due to the possibility of activating or deactivating electronic components of the vehicle electrical system, this can be put into an even more energy-efficient state. The preferred embodiment of the CMOS circuits enables a technically mature and energy-saving circuit design.

The device also has a device for amplifying the voltage characterizing the detected quiescent current, the amplification factor of the device being dimensioned such that a CMOS voltage level of the voltage characterizing the quiescent current is reached. An improved voltage level of the characterizing voltage for a possibly subsequent signal processing can be achieved by the amplification unit. In particular, the characterizing voltage is increased to a CMOS voltage level, as a result of which further subsequent processing using CMOS circuits is facilitated.

The device also includes a device for rectifying the amplified voltage. It is possible that the increased voltage has a negative sign, which is a hindrance to any subsequent further processing, or at least makes it more difficult. For this reason, rectification by a suitable device such as a CMOS circuit is advantageous.

The device can also have a device for filtering, in particular low-pass filtering, of the voltage characterizing the detected quiescent current. As a result, interference signals such as For example, thermal noise or heat noise of the actual device is filtered out, resulting in a signal with a better signal-to-noise ratio (SNR).

In addition, one embodiment provides that the comparator circuit compares the voltage with a second predefined or definable threshold value, the second threshold value preferably being a negative value and/or the second threshold value preferably being smaller than the first threshold value. With a comparator circuit designed in this way, a signaling circuit is possible not only when a first threshold value is reached, but also when a second threshold value is reached. In this way, for example, a situation-dependent circuit can be implemented, in that the charging and discharging function can be activated.

Furthermore, one embodiment provides that the device for rectifying rectifies the second threshold value, in particular when the second threshold value is a negative value. In this way it is possible, in particular in relation to previous embodiments, for two different positive threshold values to be defined.

In a further embodiment, the comparator circuit is designed to output an idle signal when the value falls below the second threshold value, the idle signal preferably having a level which can be used directly by a microcontroller. This embodiment makes it possible for the device to output an idle signal in addition to the wake-up signal. It is thus possible, for example, for the first threshold value, ie the threshold value for the output of the wake-up signal, to be higher than the second threshold value, ie that which is responsible for the output of the idle signal. As a result, the device can be put into the quiescent state when a low quiescent current is reached. Since it is advantageous to choose the level of the quiescent current as low as possible, such a low threshold value for a wake-up signal would be disadvantageous, since this would result in constant switching between the wake-up and the quiescent state, particularly due to noise. For this reason, it is advantageous for the threshold value of the wake-up signal to be above the threshold value of the idle signal, in order to achieve a targeted wake-up of the battery management system and/or the vehicle electrical system.

The comparator circuit can also have a Schmitt trigger, the output of the Schmitt trigger preferably having a level which can be used directly by a microcontroller. By using a Schmitt trigger and the hysteresis obtained as a result, an even more reliable output of the wake-up signal or the idle signal can be achieved. For example, a difference between the first threshold value and the second threshold value that lies over several powers can be realized by a Schmitt trigger.

The emitted wake-up signal and/or rest signal can also be held by the comparator circuit. This simplifies in particular a possible subsequent processing using, for example, an analog or digital circuit.

In addition, according to one embodiment, the first threshold value is in the range from 1 μV to 2000 μV, preferably 10 μV to 750 μV, particularly preferably 50 μV to 250 μV. This achieves a finely adjustable threshold value for the wake-up signal.

An embodiment also provides that the second threshold value is in the range from ±0.1 μV to ±500 μV, preferably ±1 μV to ±250 μV, particularly preferably ±10 μV to ±100 μV. In this way, a finely adjustable threshold value for the quiescent signal is realized, whereby this can be both negative and positive, depending on whether rectification is desirable or not.

In addition, one embodiment provides that the device for detecting the quiescent current flowing in at least one area of the vehicle electrical system includes at least one current sensor and/or at least one shunt. By using at least one current sensor or at least one shunt, a preferably low-impedance measuring device for the quiescent current is achieved, with the effect on the battery management system or the vehicle electrical system being minimized as a result.

Thus, according to one embodiment, the shunt has an ohmic resistance in the range from 1 μΩ to 1 mΩ, preferably 25 μΩ to 500 μΩ, particularly preferably 50 μΩ to 250 μΩ. Due to this very low-impedance measuring resistor, the current causes a voltage drop proportional to its strength, which is then measured. Influencing the battery management system or the vehicle electrical system is also almost impossible due to the very low-impedance values.

• - Erfassen eines in mindestens einem Bereich des Bordnetzes fließenden Ruhestroms,
• - Ausgeben einer dem erfassten Ruhestrom charakterisierenden Spannung,
• - Vergleichen der Spannung mit mindestens einem vorab festgelegten oder festlegbaren Schwellwert, und
• - Abgeben eines Aufwecksignals bei Überschreiten des Schwellwertes.

In a further embodiment according to the invention, the object set at the outset is achieved by a method for waking up a battery management system and/or an on-board network of a vehicle or at least one component thereof using a device according to one of the above previous embodiments are solved, the method having the following steps:

• - detecting a quiescent current flowing in at least one area of the vehicle electrical system,
• - Outputting a voltage that characterizes the detected quiescent current,
• - comparing the voltage with at least one predetermined or determinable threshold value, and
• - Output of a wake-up signal when the threshold value is exceeded.

Such a method achieves the advantages described in relation to the previous embodiments of the device. In addition, the method according to the invention makes it possible for the most energy-saving method possible to implement a wake-up signal for a battery management system and/or an on-board network.

• - Vergleichen der Spannung mit einem zweiten Schwellwert, und
• - Ausgeben eines Ruhesignals bei Unterschreiten des zweiten Schwellwerts.

According to a further embodiment, the method can also comprise the following steps:

• - comparing the voltage to a second threshold, and
• - Outputting a rest signal when the second threshold value is not reached.

This makes it possible for a rest signal for the battery management system and/or the vehicle electrical system to be implemented in addition to the wake-up signal. The method described makes it possible for the threshold values for the idle signal and the wake-up signal to be different, as a result of which the advantages already described in relation to the device are also achieved with the method.

The object set at the outset is also achieved by a system having at least one device according to one of the preceding embodiments, at least one vehicle electrical system, and at least one battery. This achieves the advantages described in relation to the previous exemplary embodiments of the device.

The task stated at the outset is also achieved by a computer-readable storage medium which contains instructions which cause at least one processor to implement a method according to one of the preceding embodiments of the method when the instructions are executed by at least one processor. The computer-readable medium according to the invention, including computer-executable instructions, results in improved IT handling of the method according to the invention.

• 1: eine Ausführungsform der Erfindung in schematischer Ansicht;
• 2: eine Detailansicht des Stromfluss-Aufwachsensors der 1.

The invention is explained in more detail below with reference to figures. Here show:

• 1 1: an embodiment of the invention in a schematic view;
• 2 : a detailed view of the current flow growth sensor 1 .

In the following description, the same reference numbers are used for parts that are the same or have the same effect.

In the near future, standard battery systems for vehicles, or at least one component thereof, will have a complex management system. For example, a management system is necessary for lithium-ion batteries or lithium-ion cells, since such a management system can be used, for example, to charge the cells uniformly, to carry out various safety functions, status monitoring and various other safety-related functions.

It is desirable for such a management system to have what is known as a sleep mode, in which case the lowest possible energy consumption is desirable. In this case, a special microcontroller wake-up signal must be implemented, which is generally referred to as the ignition function. If this is not available, this functionality must be implemented with another sensor.

The present invention describes, for example, a sensor or a device, which measures the current flow in the vehicle electrical system or at least one component thereof and outputs a wake-up signal if a positive or negative current flows that is higher than the current flow in the vehicle's sleep mode or a component thereof. The sensor or the device can have different resistances, with the different resistances having different resistance values in order to set the necessary wake-up points or the necessary positive or negative current flows.

According to embodiments of the invention, for example, actuating a door opener of the vehicle, activating a signal lamp or other light source, activating a vehicle entertainment system and/or actuating/activating another electrical consumer in the vehicle is sufficient to initiate the microcontroller wake-up signal.

the 1 shows an embodiment of the device according to the invention for waking up a battery management system (BMS) and/or an on-board network of a vehicle or at least one component thereof. A battery 1 is shown connected to both a load 2 and a resistor 3 . The resistor 3 is, for example, an ohmic resistor, preferably a so-called shunt resistor. The load 2 and the resistor 3 are also connected to each other, as shown schematically. The load 2 can be the vehicle's electrical system, for example, or just a part of it. In the present embodiment, the resistor 3 is the device for detecting a quiescent current flowing in at least one area of the BMS or vehicle electrical system. Using Ohm's formula, this detected quiescent current can be converted into a characterizing voltage.

Also are in the 1 two measuring lines 4 can be seen. The measuring lines 4 shown connect the resistor 3 to a current flow wake-up sensor 5. The current flow wake-up sensor 5 has a comparator circuit which emits a wake-up signal when the threshold value is exceeded, this wake-up signal preferably having a voltage level which can be used directly by a microcontroller or is processable.

2 shows a detailed view of the current flow growth sensor 5. The voltage measured in the area of the BMS or the vehicle electrical system is passed to the input filter 6, indicated by an arrow. The input filter 6 has the function of filtering the measured voltage so that, for example, thermal noise or shot noise is filtered. The filtered voltage is fed to a precision amplifier 7 . This has an amplification factor which is dimensioned in such a way that a CMOS voltage level is reached at the output of the precision amplifier 7 . The voltage amplified in this way is passed on to a precision rectifier 8 . The precision rectifier 8 is designed in such a way that it rectifies any negative voltages that may occur, so that a positive signal is achieved.

A possible output signal of the precision rectifier 8 is in the 2 pictured next to this one. In this embodiment, the comparator circuit is, for example, a Schmitt trigger 9, which compares the voltage with two previously defined or definable threshold values and when the value falls below the lower threshold value, a rest signal is output. The idle signal is preferably at a level that can be used directly by a microcontroller. The Schmitt trigger 9 has a hysteresis, as a result of which different voltage threshold values can be defined for the idle signal or a wake-up signal. These signals can be output by the Schmitt trigger 9 either through a digital or analog output 10 . An advantage of this output by the Schmitt trigger 9 is that the output 10 already has a corresponding voltage level, so that the signal output can be used directly by a microcontroller of a subsequent wake-up or sleep system (not shown). It is of course also possible for the Schmitt trigger 9 to hold the output wake-up signal or the output idle signal for a period of time to be determined.

The first voltage threshold value is preferably in a range from 1 μV to 2000 μV, particularly preferably from 10 μV to 750 μV. It has turned out to be particularly preferred if the first voltage threshold value is selected in a range from 50 μV to 250 μV. The second voltage threshold lies, for example, in a range from ±0.1 μV to ±500 μV, preferably in the range from ±1 μV to ±250 μV, particularly preferably in the range from ±10 μV to ±100 μV.

The resistor is, for example, a shunt with a resistance value in the range from 1 μΩ to 1 mΩ, preferably 25 μΩ to 500 μΩ, particularly preferably 50 μΩ to 250 μΩ.

Reference List

1

battery

2

load

3

Resistance

4

test leads

5

Current flow wake-up sensor

6

input filter

7

precision amplifier

8th

precision rectifier

9

Schmitt trigger

10

Exit

Claims (15)

Device for waking up a vehicle battery (1), a battery management system, BMS, and/or an on-board network of a vehicle or at least one component thereof, having: - a device (3) for detecting a quiescent current flowing in at least one area of the BMS or on-board network and for Outputting a span that characterizes the detected quiescent current voltage, and - a comparator circuit for comparing the voltage with at least one predetermined or determinable threshold value, the comparator circuit being designed to emit a wake-up signal when the threshold value is exceeded, the wake-up signal having a voltage level that can be used directly by a microcontroller , the device having a device for activating and/or deactivating electronic components of the vehicle electrical system based on the wake-up signal, the device having one or more CMOS circuits, the device having a device (7) for amplifying the voltage characterizing the detected quiescent current having, wherein the amplification factor of the device is dimensioned such that a CMOS voltage level of the voltage characterizing the quiescent current is reached; and wherein the device comprises means (8) for rectifying the boosted voltage. device after claim 1 , wherein the device has a device for low-pass filtering of the voltage characterizing the detected quiescent current. Apparatus according to any preceding claim, wherein the comparator circuit compares the voltage to a second predetermined or determinable threshold, the second threshold being a negative value, and/or the second threshold being less than the first threshold. device after claim 3 , wherein the device for rectifying rectifies the second threshold value. device after claim 3 or 4 , wherein the comparator circuit is designed to output a rest signal when the value falls below the second threshold value, the rest signal having a level that can be used directly by a microcontroller. Apparatus as claimed in any preceding claim, wherein the comparator circuit comprises a Schmitt trigger (9), the output of the Schmitt trigger (9) being at a level which can be used directly by a microcontroller. Device according to one of the preceding claims, wherein the emitted wake-up signal and/or sleep signal is held by the comparator circuit. Apparatus according to any one of the preceding claims, wherein the first threshold is in the range of 50µV to 250µV. Apparatus according to any preceding claim, wherein the second threshold is in the range of ±10µV to ±100µV. Device according to one of the preceding claims, wherein the device (3) for detecting the quiescent current flowing in at least one area of the vehicle electrical system has at least one current sensor and/or at least one shunt. device after claim 10 , whereby the shunt has an ohmic resistance in the range from 50µΩ to 250µΩ. Method for waking up an on-board network of a vehicle or at least one component thereof by means of a device according to one of the preceding claims, the method having the steps: - detecting a quiescent current flowing in at least one area of the vehicle electrical system, - Outputting a voltage that characterizes the detected quiescent current, - comparing the voltage with at least one predetermined or determinable threshold value, and - Output of a wake-up signal when the threshold value is exceeded. procedure after claim 12 , the method having the steps: - comparing the voltage with a second threshold value, and - outputting a rest signal when the voltage falls below the second threshold value. System with at least one device according to one of Claims 1 until 11 , At least one vehicle electrical system, and at least one battery (1). A computer-readable storage medium containing instructions that cause at least one processor to perform a method according to any one of Claims 12 or 13 to be implemented when the instructions are executed by at least one processor.

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