WO2017060354A1

WO2017060354A1 - Vehicle battery device

Info

Publication number: WO2017060354A1
Application number: PCT/EP2016/073881
Authority: WO
Inventors: Tobias Galli; Christian Bottke; Stephanie PREISLER
Original assignee: Continental Automotive Gmbh
Priority date: 2015-10-09
Filing date: 2016-10-06
Publication date: 2017-04-13
Also published as: DE102015219589A1

Abstract

The invention relates to a vehicle battery comprising a first accumulator (10a, b) having a centre tap (12), a second accumulator (20) having a positive pole, and comprising a first and a second positive connection (14, 24). The positive pole of the second accumulator is connected to the centre tap (12) of the first accumulator. The second accumulator (20) has a nominal voltage that is smaller than the nominal voltage of the first accumulator (10). The first positive connection (14) is connected to a positive pole of the first accumulator (10a, b). The second positive connection (24) is connected to the positive pole of the second accumulator (20). A ground connection (30) of the vehicle battery device is connected to a negative pole of the first accumulator (10a, b) via a first switch (SW1). The ground connection is also connected to a negative pole of the second accumulator (20) via a second switch (SW2).

Description

description

Vehicle battery orrichtung motor vehicles have a vehicle electrical system in order to provide numerous elekt ^¬ innovative components inside and outside of the drive train with electrical energy. With increasing electrification or with increasing power of electric machines within the vehicle, the nominal voltage should be increased, since at higher nominal voltages comparatively smaller cable cross-sections and maximum rated currents are required. However, in order not to have to change all components to higher vehicle voltages, batteries are used, which can serve different electrical systems branches with different nominal voltages. However, as shown below, there are challenges in the combination of different nominal voltages within the vehicle electrical system or within the same vehicle battery device. Batteries consist of serial arrangements of individual cells, which reach the required voltage or capacity by the sum of the series connection. Furthermore, in order to be able to represent larger capacities, two or more cells can be connected in parallel. These are permanently connected and can not be disconnected during operation.

In case of a defect in a cell of the cell string, this may lead to complete failure of the entire battery and breakdown of the on-board power supply. Especially in applications where only one starter generator charges the battery, but at the same time the 12V supply must be permanently ensured, this aspect is gaining in importance. The supply of the 12V consumers should not be interrupted, since otherwise no redundant element can take over the energy supply. The supply from the DC / DC converter may not be sufficient here to supply the consumers satisfactorily.

The aim is to ensure a permanent supply of the vehicle with energy, so that the driver is able to bring the vehicle in case of a defect safely and in sufficient time, the vehicle to a halt.

Representation of embodiments of the invention

This object is solved by the subject matter of claim 1. Further embodiments, features and characteristics will become apparent from the dependent claims and from the following description and the accompanying drawings.

Cells are connected in parallel in a modular fashion in order to be able to deactivate this strand in the event of a defect within one of the strands, without having to interrupt the operation. So far, this has been solved by connecting two or more energy suppliers or storage batteries in parallel.

In the presently described vehicle battery device, there is the opportunity to represent vehicle electrical system branches with different nominal voltages ^¬ with a device and supply to. The supply of one of the Bordnetze (the electrical system branch with a higher rated voltage than the rated voltage of another electrical system branch) can be realized switched off, since the vast majority of vehicle consumers in the

Bordnetzzweig can be located with the lower nominal voltage. Within the vehicle battery device, the energy sources are divided into at least two accumulators. With this arrangement, it is now possible to disable this defective part of the vehicle battery device in case of a defect in a cell string through the existing switch. The control the switch, in particular MOSFETs or other semiconductor switches, takes over a control unit in the vehicle battery device. This decides on the basis of the available data, if and which strand is deactivated and controls the corresponding switch.

The vehicle battery device includes a control unit configured to open the switch connected thereto upon detection of a cell defect within one of the accumulators. The control unit may have an input which is connected to the accumulators to measure their voltage, internal resistance or the current to the accumulators. The control unit may further include an input configured to acquire data from a diagnostic output of a battery management unit, the data representing (directly or indirectly) whether the first battery is defective or not and whether the second battery is defective is or not. Specifically, the control unit is connected to the batteries or accumulators associated battery management unit and adapted to detect whether the first battery exceeds a predetermined current threshold or not, and whether the second battery exceeds a predetermined current ^¬ threshold or not. In particular, the control unit is set up to detect whether or not there is a defect in the first accumulator, and whether or not there is a defect in the second accumulator. As a defect, for example, a short circuit and / or exceeding a predetermined upper temperature limit and / or exceeding a predetermined internal resistance upper limit and / or falls below a predetermined lower voltage limit can be considered by the relevant accumulator.

By the requirement to have to provide at least one electrical system branch permanently (especially with the lower Rated voltage than the other), switches are used. As a result, charging (in particular, charge balance) can be prevented. At the same time, via a body diode of the switch, provided that it has one, an electrical system branch (in particular the one with the lower rated voltage than the other) can still be supplied to a certain extent.

Over time, the defective battery becomes more and more discharged, and can no longer contribute to the supply. Loading (and thus a load on the generator, a transducer or other rechargeable battery) is not possible due to the no longer ge ^¬ closed switch.

The same method is applicable, as soon enhanced aging cells in a strand can be seen and thereby to be deactivated permanently or for a certain time to reach the Ge ^¬ samtlebensdauer the battery device.

A vehicle battery device having a first and a second accumulator is proposed. The first accumulator has an intermediate tap. The second accumulator has a positive pole. This is connected to the intermediate tap of the first accumulator. The second accumulator has a rated voltage which is smaller than the nominal voltage of the first accumulator. For example, the first accumulator has a nominal voltage of 48 volts, while the second accumulator has a nominal voltage of 12 volts. As a result, an on-board electrical system can be supplied with 48 V nominal voltage and a vehicle power supply branch with 12 V nominal voltage. Through the intermediate tap, the first accumulator can support the second accumulator or (in case of failure of the second accumulator) replace in its function.

The vehicle battery device has a first positive terminal and a second positive terminal. Both are _n

5 for different rated voltages or for electrical systems branches of different nominal voltage provided. The first positive terminal is connected to the first accumulator, in particular to a positive pole of the first accumulator. The second positive terminal is connected to the second accumulator, in particular to the positive pole of the second accumulator.

The vehicle battery device further has a ground connection. This is connected via a first switch to the first accumulator, in particular to a negative terminal of the first accumulator. The ground terminal is connected via a second switch to the second accumulator, in particular with a negative pole of the second accumulator. By means of the switch, one of the accumulators of the

Ground connection to be disconnected if the accumulator is defective or aged too much. By means of the switches it can be selected which of the accumulators is used for the supply or which of the accumulators supplies current to (or receives from) the second positive terminal.

The vehicle battery device further has a

DC / DC converter on. This has a first converter side and a second converter side. The first converter side is connected to the first accumulator. The first converter side is connected in particular to the positive pole of the first accumulator. Furthermore, the first converter side can be connected to the intermediate tap (or also to the negative pole of the first battery). The second converter side is connected to the second accumulator. In particular, the second converter side is connected to the positive pole of the second accumulator (or to the intermediate tap connected thereto). Furthermore, the second converter side is preferably connected to the negative terminal of the second accumulator or to the ground terminal. The DC / DC converter is set up, to convert electrical voltage between the first and the second converter side. The DC / DC converter may be a bidirectional converter or a unidirectional converter, which is in particular designed to transmit energy from the first converter side to the second converter side. The DC / DC converter is in particular a DC-DC converter, which is designed, for example, as a charge pump, down converter, up-converter, or inverse converter. The DC / DC converter can be designed as a converter with or without galvanic isolation (ie with or without a transformer).

The vehicle battery device may further include a third switch. About this third switch, the positive pole of the first accumulator can be connected to the first positive terminal. This allows a further, individually switchable connection of the first accumulator. The third switch may be arranged between the positive pole of the first accumulator and the first positive terminal of the vehicle battery device. The third switch may further be provided between a connection point of the first converter side and the positive pole of the first accumulator and the first positive terminal of the vehicle battery device.

The vehicle battery device may further include a control unit. This is connected to the first and the second accumulator, in particular to detect a potential, a voltage, a flowing current or a temperature of one of the respective accumulators or individual cells of one of the accumulators or groups of cells of one of the accumulators. For this purpose, the control unit has a measuring or signal input. The control unit is set up to detect a cell defect in one of the accumulators. As a cell defect is a complete failure of at least one cell of the ^¬ be taken accumulator (or the entire storage battery) and / or a degree of aging of at least one cell of the ^relevant accumulator or of a cell stack section of the accumulator or of the entire accumulator, which exceeds a predetermined threshold value.

The control unit is drivingly connected to the first and the second switch. Further, the control unit may be drivingly connected to the third switch. In particular, the control unit may be connected to the DC / DC converter driving. The control unit can also the

Downstream of DC / DC converter to detect from this a signal that identifies at least one state of the DC / DC converter. As a state of the DC / DC converter, for example, the temperature, a current, a load state, a potential, a voltage, a switching frequency or an operating status

(Fault or nominal operation) of the DC / DC converter. Furthermore, the control unit can be drivingly connected to a rechargeable battery or to both rechargeable batteries, in particular to a battery management unit of the rechargeable battery, which is set up, for example, to control charge ^equalization between cells of the respective rechargeable battery. The control unit is set up to open the connected switch upon detection of a cell defect within one of the accumulators. If the first accumulator is detected as defective, the first switch is opened. If the second accumulator is detected as defective, the second switch is opened. For this purpose, the control unit can have a control output which is connected to a respective control input of the control unit

Switch (for example, base or gate) is connected. The function of the control unit may be realized by logic gates, analogue devices, a microprocessor with attached program memory or a combination thereof. The function results from the interconnection of these components or by a program in the program memory, the designed to drain from the microprocessor. The control unit may have a communication interface ^¬, can be connected to the higher-level control devices. Further, the DC / DC converter may include a communication section parts which is adapted for connection to a data bus of the vehicle, such as a communication interface ^¬ body in the CAN bus standard (ISO 11898).

The first and / or the second positive terminal (or the ground terminal) of the vehicle battery device may be secured with a fuse. The relevant port is equipped with a serial fuse. If the current at the terminal exceeds the fuse current threshold, it triggers and disconnects the relevant terminal. The fuse can be a fuse or a circuit breaker that can be reset as soon as the current threshold is un ^¬ undershot.

The first accumulator is preferably a lithium accumulator. The second accumulator preferably a lead-acid battery. The lithium secondary battery may have a cell stack, with a connection between two adjacent cells taken out as the intermediate tap. The lead-acid battery can have, for example, 6 lead-acid cells. The lithium accumulator can have 12 lithium cells (each with a rated voltage of, for example, about 3.5 volts, about 3.7 volts, about 3.8 volts, about 4 volts, or about 4.2 volts). The nominal cell voltage depends on the type of lithium cell, in particular on the electrode material pairing, so that a large number of lithium cell types are possible here. A cell stack section of the first accumulator, which connects the negative pole to the intermediate tap, can have, for example, 3 cells (with a total nominal voltage of this cell stack section of approximately 12 volts, corresponding to the nominal voltage of the second accumulator). One "

Cell stack portion of the first accumulator ver ^¬ binds the Zwi ^¬ rule tap with the positive pole (the first accumulator), for example, 9 cells (with a total nominal voltage of this cell stack section of about 36 volts). Overall, the first accumulator can have a cell stack of 12 lithium cells having a total nominal voltage of 48 volts.

The nominal voltage between the intermediate tap and the positive pole (or the total rated voltage of the relevant cell stack section) of the first accumulator is preferably greater than the nominal voltage of the second accumulator.

The first switch and the second switch, and in particular the third switch (if present) may be self-closing. The first and the second switch may further be self-opening, such as to have po ^¬ tentialfrei the connections in case of failure of the drive. Furthermore, they can be self-opening. The first switch and the second switch are preferably semiconductor switches, but may also be designed as electromechanical switches such as relays. The third switch is preferably also a semiconductor switch, but may also be provided as an electromechanical switch. Transistor switches are preferably used as semiconductor switches, for example MOSFETs (for example n-MOSFETs) or IGBTs or other field-effect or bipolar transistors.

The first switch and the second switch may be formed as mentioned as a semiconductor switch. Therefore, the first switch and the second switch may have an inverse diode. The inverse diode results from the semiconductor structure of the semi ^¬ conductor switch. The forward direction of the inverse diode points from the ground connection to the respective accumulators. There may further be a diode in parallel with terminals of the first and / or ₁

be switched second switch. This diode has a forward direction which corresponds to the forward direction of the inverse diode. In addition, in order to support the inverse diode, such a diode can also be connected in parallel even if the switch already has an inverse diode.

The rated voltage of the second accumulator may substantially correspond to the rated voltage of a cell stack (or cell stack section) between the intermediate tap and the negative pole of the first accumulator. The term "essentially" means that the values in question do not fall apart by more than 20%, 10%, 5% or 2%. The first and second accumulators are based on different cell types. For this reason, an exact match would be difficult. A deviation of the nominal cell voltage is possible with parallel switch of the second accumulator and said cell stack, as the Un ^¬ terschied with different states of charge (and thus different voltages) may be compensated. Furthermore, the voltage of the second accumulator can also be determined by the

Nominal voltage differ. In particular, as an example, at a nominal voltage of 12 volts of the second accumulator, the operating voltage may also be 13 or 14 volts or even 11 volts.

The rated voltage of the first accumulator may be substantially 12V, 13V or 14V. The nominal voltage of the cell stack (or cell stack portion) of the first accumulator, which is located between the intermediate tap and the negative pole of the first accumulator, may be substantially 12 volts, 13 volts or 14 volts. The nominal voltage between the positive pole and the negative pole of the first accumulator can be substantially 46 volts, 48 volts or 50 volts. "Substantially" means that the ^relevant values do not differ by more than 20%, 10 or 2%. The vehicle battery device may have a housing in which said switches, the accumulators or their cells or cell stacks, and the control unit (if present) are housed. The connections are accessible through the housing. Alternatively, the terminals may extend to the exterior of the housing (and thus through the wall of the housing). Furthermore, a data interface can be attached to the housing, which serves as a physical interface of the communication interface.

FIG. 1 shows a circuit diagram for explaining the vehicle battery device described here

The exemplary vehicle battery device shown in Figure 1 has a first accumulator 10a, b with a

Intermediate tap 12 has. The first accumulator 10a, b has a first cell stack or cell stack section 10a and a second cell stack or cell stack section 10b. these are connected to each other at the intermediate tap 12. The intermediate tap 12 is led out to the point Bl. In elekt ^¬-driven respects cell stack section 10a and the second cell stack section 10b together form the first accumulator.

A second accumulator 20 has a positive pole connected to the positive pole of the second cell stacking portion 10b. The positive pole of the second cell stacking section 10b corresponds to the negative pole of the first cell stacking section 10a. The positive pole of the second accumulator 20 is connected to the point Bl and thus connected to the intermediate tap of the first accumulator 10a, b. The positive pole of the first accumulator 10a is

(switchable) connected to a first positive terminal 14 of the device shown. The positive pole of the first accumulator 10a, b corresponds to the positive pole of the first cell ^¬ stacking section 10a of the first accumulator. A second positive terminal 24 of the illustrated device is connected to the positive pole of the second accumulator 20 and the intermediate tap 12 (and thus point Bl). By way of example, the nominal voltage of the first accumulator 10a, b is 48 volts; the rated voltage of the cell stack section 10b is 12 volts while the second secondary battery 12 has a nominal voltage of 12 volts. Charge compensation can take place via the point B1 between the second accumulator 20 and the (second cell stack section of) the first accumulator (s).

A ground connection 30 is connected via a first switch SW1 to a negative pole of the first accumulator (or its second cell stack section 10b). The ground terminal 30 is connected via a second switch SW2 to a negative pole of the second accumulator. The ground terminal 30 is shown in two parts of a ^¬ sake of simplicity, but may be realized as a common terminal contact. The switches SW1 and SW2 are MOSFETs, respectively. The vehicle battery device further has a

DC / DC converter 40 with a first converter side 42 and a second converter 44 side. As an example, the first one

Transducer 42 provided for a voltage of 48 volts, and the second converter side 44 is provided for a voltage of 12 volts. For better understanding, these voltage specifications are shown in the figure, but are intended to be exemplary only and in no way limit the idea described here. The first converter 42 is connected to a point AI whose potential corresponds to that of the first positive terminal 14 and the potential of the positive pole of the first accumulator 10a (if switch SW3 is closed). The first converter side 42 is further connected to the intermediate tap 12, ie to the negative pole of the cell stacking section 10 of the first accumulator. These two connections form alternative (positive) Converter terminals for the converter 42, which can thus have the entire voltage of the first accumulator 10a, b, or only via the voltage of the second cell stack portion 10b of the first accumulator. A control unit 70 may be configured to drive the converter 42 to select one or the other converter connection. For example, if the first cell stack section 10a is defective, then the first

Transducer side 42 are connected to the intermediate tap 12 and it is selected the corresponding converter terminal. The converter 40 or the first converter side 42 is also connected to ground or to the ground connection 30 or is "ground-floating" or potential-free The second converter side 44 is connected to the point Bl and thus to the positive pole of the second accumulator 20 is connected to the intermediate tap 12 of the first accumulator 10. The second converter side 44 is connected in particular to the positive pole of the second accumulator 20 and to the ground connection 30. The converter can have a common connection for ground for both converter sides 42, 44 However, the converter sides 42, 44 have different connections, on the one hand, for connection to the first and, on the other hand, for connection to the second accumulator A communication interface of the converter 50 is used for data transmission to or from a data bus (not shown). outside the illustrated vehicle battery device.) The terminals 14, 24 and 30 can also be considered as interfaces. The terminals 14, 24 and 30 are in particular electrical power terminals. The An ^{¬ connections} 14, 24 and 30 are preferably designed for rated currents of at least 50, 100, 200 or 500 amps.

A third switch SW3 connects the positive pole of the first accumulator 10a, 10b (or the positive pole of the first cell ^¬ stacking portion 10a) with the first positive terminal 14 of the vehicle battery device. The illustrated vehicle battery device further comprises, as already mentioned, a control unit 70. This is connected to the first and the second accumulator, as shown by the pointing in both directions arrows between the control unit 70 on the one hand and the first and second accumulator (reference numeral 10a, b, 20) on the other. The control unit 70 is configured to detect a cell defect in one of the accumulators 10a, b; 20 to capture. The control unit 70 is further drivingly connected to the first switch SW1 and the second switch SW2. The control unit 70 is set up to open the switch SW1 or SW2 connected thereto upon detection of a cell defect in one of the accumulators. This driving connection is shown with the arrows between the control unit 70 on the one hand and the first and second switches SW1, SW2 on the other hand. Further, the third switch SW3, which is located between the positive pole of the first accumulator 10a, b and the first positive terminal 14, is driven by the control unit 70. This is illustrated by the arrow between the control unit 70 and the third switch SW3.

The third switch SW3 and thus also the positive pole of the first accumulator 10a, b is connected to the point A2. This in turn is connected to the point AI, which in turn is connected to the converter 40 (in particular to the converter side 42).

Between the positive pole of the first accumulator 10a, b and the first positive terminal 14, a fuse Fl is provided. Between the positive pole of the second accumulator 12 and the second positive terminal 24, a fuse F2 is provided. The components numbered 10b, 20, 12, 24, 44, Bl and F2 are associated with a rated voltage of 12 volts and a service portion formed by the vehicle battery device, respectively. The components with the reference numerals 10a + 10b, 14, 42, SW3, AI, A2, Fl are associated with a rated voltage of 48 volts and another supply section, which is also formed by the vehicle battery device.

The switches SW1, SW2 are semiconductor switches, in particular field-effect transistors. In each case, they have an inverse diode whose forward direction, as shown, from the ground connection 30 to the respective accumulators 10a, b; 20 points out. The forward direction is away from ground and points towards the positive supply rail (i.e., to the accumulators).

A symbolically illustrated housing 60 surrounds the components with the reference numerals 10a, b, 20, 40, 70, SW1, SW2, SW3, Fl and F2. The terminals 14, 24 and 30 are accessible from the outside, ie extend at least partially through the housing. As mentioned, the components with the reference numbers Be ^¬ SW3, 40, 50, 60 and 70 are optional in particular.

Claims

Vehicle battery device with:

- A first accumulator (10a, b) having an intermediate tap (12);

- A second accumulator (20) having a positive pole

which is connected to the intermediate tap (12) of the first accumulator, the second accumulator (20) having a nominal voltage which is smaller than the nominal voltage of the first accumulator (10); a first positive terminal (14) and a second positive terminal (24), wherein the first positive terminal (14) is connected to a positive pole of the first accumulator (10a, b) and the second positive terminal (24) is connected to the positive pole of the second one Accumulator (20) is connected, wherein the vehicle battery device further comprises:

a ground terminal (30) which is connected via a first switch (SW1) to a negative terminal of the first Akkumu ^¬ lators (10a, 10b), and via a second switch (SW2) a negative terminal of the second accumulator (20) is connected and the vehicle battery device further comprising:

a control unit, upon detection of a cell defect which is set up within one of the Ak ^¬ kumulatoren (10a, b; 20) the connected switches (SW1, SW2) to open.

A vehicle battery device according to claim 1, further comprising a DC / DC converter (40) having a first

Transducer side (42) connected to the first accumulator (10a, 10b) and having a second transducer side (44) connected to the second accumulator (20), wherein the DC / DC converter (40) set up is to convert electrical voltage between the first and the second converter side (42, 44).

Vehicle battery device according to claim 1 or 2, further comprising a third switch (SW3) via which the positive pole of the first accumulator (10a, 10b) is connected to the first positive terminal (14).

Vehicle battery device according to one of the preceding claims, further comprising a control unit (70) which is connected to the first and the second accumulator (10a, 10b, 20) and is adapted to detect a cell defect in one of the accumulators, wherein the control unit ( 70) drivingly connected to the first and the second switch (SW1, SW2) and is arranged to open upon detection of a cell defect in one of the accumulators the switch (SW1, SW2) connected thereto.

Vehicle battery device according to one of the preceding claims, wherein the first and / or the second positive terminal with a serial fuse (Fl, F2) is secured.

Vehicle battery device according to one of the preceding claims, wherein the first accumulator is a lithium secondary battery and the second accumulator is a lead-acid battery.

Vehicle battery device according to one of the preceding claims, wherein the nominal voltage between the intermediate tap (12) and the positive pole of the first accumulator (10a, 10b) is greater than the rated voltage of the second accumulator (20). Vehicle battery device according to one of the preceding claims, wherein the first switch (SW1) and the second switch (SW2) are semiconductor switches or electromechanical switches that are self-closing or self-opening.

A vehicle battery device according to claim 8, wherein the first switch (SW1) and the second switch (SW2) have an inverse diode whose forward direction from the ground terminal (30) faces the respective accumulators.

Vehicle battery device according to one of the preceding claims, wherein the rated voltage of the second accumulator (20) substantially corresponds to the nominal voltage of a cell stack (10b) between the intermediate tap (12) and the negative terminal of the first accumulator.

11. The vehicle battery device according to one of the preceding claims, wherein the rated voltage of the second accumulator substantially corresponds to 12 volts, 13 volts or 14 volts, the rated voltage of a cell stack (10b) of the first Ak ^¬ kumulators extending between the intermediate tap (12) and the Minuspol the first accumulator is located, essentially 12 volts, 13 volts or 14 volts and corresponds to the

Nominal voltage between the positive pole and the negative terminal of the first accumulator (10a, 10b) substantially equal to 46 volts, 48 volts or 50 volts.