Battery system and method for providing a first voltage and for being simultaneously charged with a second voltage

Abstract

The invention relates to a battery system (10) for providing a first voltage and for being simultaneously charged with a second voltage, the battery system comprising: a plurality of battery devices (12a-12d), each having a positive terminal (20a-d) and a negative terminal (20e-h); a low-voltage connection (14) for providing the first voltage; and a charging connection (16) for charging the battery devices (12a-12d) with the second voltage, wherein each of the positive terminals (20a-d) can be switchably connected to the low-voltage connection (14) via an associated positive parallel switching device (18a-18d), and each of the negative terminals (20e-h) can be switchably connected to the low-voltage connection (14) via an associated negative parallel switching device (18e-18h); characterised by terminal connection lines (24a-24c) which switchably connect the battery devices (12a-12d) to form a series connection by connecting in each case one positive terminal (20a-d) to one negative terminal (20e-h) via in each case one series switching device (22a-22c), such that two terminals (20a-h) of end-positioned battery devices (12a-12d) form series-connection terminals (26a, 26b) of the series connection, wherein the series-connection terminals (26a, 26b) are connected to the charging connection (16), and the series switching devices (22a-22c) and / or the parallel switching devices (18a-18h) are contactors with return lines.

Description

[0001] Battery system and method for providing a first voltage and simultaneously charging with a second voltage

[0002] The present invention relates to a battery system and a method for providing a first voltage and simultaneously charging with a second voltage.

[0003] The present invention is based on known systems for supplying electrical power to a battery-electric vehicle at low voltage. Typically, 48V is used for this purpose.

[0004] However, in low-voltage battery systems, it is a disadvantage that charging takes a long time due to the low voltage.

[0005] The object of the present invention is to eliminate, at least partially, the disadvantages described above in a cost-effective and simple manner.

[0006] In particular, the object of the present invention is to provide a battery system in a cost-effective and simple manner which can supply vehicles with a low-voltage voltage and be charged quickly.

[0007] The foregoing problem is solved by a battery system having the features of claim 1, and by a method having the features of claim 7. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the device according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention always refers, or can refer, to each other.

[0008] According to the invention, a battery system is intended to enable the provision of a low voltage and rapid charging. Such a battery system comprises a plurality of battery units, each with a positive and a negative terminal, a low-voltage connection for providing the first voltage, and a charging connection for charging the battery units with the second voltage. Each of the positive terminals can be switched to the low-voltage connection via a positive parallel switching device. Similarly, each of the negative terminals can be switched to the low-voltage connection via a negative parallel switching device.The battery system also includes terminal connection cables, which connect the battery units to form a series circuit by connecting one positive terminal to one negative terminal via a series switching device, so that two terminals from adjacent battery units form series terminals of the series circuit. The series terminals are connected to the charging port.

[0009] To enable rapid charging of the battery system with direct current despite the low output voltage at the low-voltage connection, preferably via a fast-charging function, the battery can be switched to high-voltage mode for the duration of the charging process. This approach offers several advantages.

[0010] Initially, the option of using a low-voltage system remains. In a vehicle using this battery system, components can be used that have lower component costs compared to those required for a high-voltage system. At the same time, the components needed for a switchable battery are less expensive than multiple on-board chargers or a DC-DC converter, which would achieve similar functionality. Furthermore, the charging speed is faster compared to conventional low-voltage systems.

[0011] The core concept of a battery system according to the invention is that the functionality of the low-voltage system to provide a low-voltage voltage at the low-voltage connection is not interrupted by the simultaneous series connection and high-voltage charging of the battery components of the battery system. Battery components can be battery cells or battery modules. The low-voltage connection is configured to provide the first voltage. For this purpose, it can have a connector or be permanently connected to the components to be supplied. The charging connection preferably includes a plug connection that allows the vehicle to be connected to an external power source. The charging connection serves to provide electrical energy for charging the vehicle battery and is preferably equipped with safety features to ensure a safe charging process.The charging port is preferably also connected to a supply connection. This allows the vehicle to be supplied with high voltage during operation and / or during the charging process. The parallel switching devices are switching devices used to connect the battery components in parallel and to connect them to the low-voltage connection. The prefixes "positive" and "negative" serve only to distinguish whether the parallel switching devices are connected to the positive or negative terminal of the battery components. The terminal connecting leads each connect a positive terminal of one battery component to a negative terminal of another battery component. These terminal connecting leads can also be switched via a series switching device, so that when the series switching devices are closed, the battery components are connected in series.In this system, two of the battery units are connected to only one other battery unit each via the terminal connection leads, while the other battery units are each connected to two other battery units via the terminal connection leads. The battery units connected to only one other battery unit are referred to as end-of-line battery units, as they form the end of the series connection. Consequently, a positive terminal of one of the two end-of-line battery units and a negative terminal of the other end-of-line battery unit are not connected to any other battery units. These terminals are referred to as series terminals. The series terminals are preferably connected to the charging port such that their connection point is located between the battery unit and one of the parallel terminals.It can be advantageous if, in a battery system according to the invention, the first voltage is lower than the second voltage.

[0012] There are further advantages if the initial voltage is 48 V. This allows for easy integration into a vehicle battery system.

[0013] Further advantages are achieved if the second voltage is at least 150 V. If the battery units each have an output voltage of 48 V, a second voltage of at least 150 V for charging the battery system is achieved if the battery system comprises four battery units connected according to the invention. With such a charging capacity, the charging time can already be significantly reduced. Of course, higher values ​​for the second voltage are also achievable. For this purpose, a larger number of battery units can be connected to form the battery system. Similarly, lower values ​​for the first voltage can be selected.

[0014] According to the invention, contactors with return lines are provided as series and / or parallel switching devices. Contactors with return lines are also referred to as safety-oriented contactors. These provide greater safety and prevent voltages at the low-voltage connection that exceed the first output voltage, thereby protecting vehicle components from excessively high applied voltages.

[0015] Finally, the battery system can be a vehicle battery system, and the low-voltage connection can supply at least one of the vehicle's thermal systems with electrical energy. This particular embodiment of the invention offers special advantages in temperature-critical applications. In particular, this embodiment makes it possible to cool the battery system with the voltage applied to the low-voltage connection while the battery system is being charged with direct current via the charging port. Other thermal systems of a vehicle can also be operated without interruption using this invention. This allows vehicles to be operated more comfortably even in harsh climates, and enables the uninterrupted operation of vehicle bodies that have a cooling system. In the latter case, the integrity of the cold chain can be ensured.

[0016] Another object of the present invention is a method for providing a first voltage and simultaneously charging with a second voltage using a battery system according to one of the preceding claims, comprising the steps:

[0017] Connecting a first battery unit to the low-voltage connection by closing one positive and one negative parallel switching device each belonging to the first battery unit; and thereby providing the first voltage at the low-voltage connection;

[0018] Closing the series switching devices to connect the battery devices to a series circuit with two poles of edge battery devices, such that the two poles of the edge battery devices form series circuit poles of the series circuit, the series circuit poles being connected to the charging terminal; and thereby charging the battery devices with the second voltage via the charging terminal.

[0019] Parallel switching devices associated with battery systems are those devices that are directly connected to the respective battery system without any other electrical components being interposed. In other words, parallel switching devices associated with battery systems are those that can disconnect the respective battery system from the low-voltage connection and / or connect the respective battery system to the low-voltage connection.

[0020] The method may preferably include the further step of: disconnecting a first battery device from the low-voltage connection by opening one positive and one negative parallel switching device belonging to the first battery device.

[0021] By disconnecting a first battery unit from the low-voltage connection, the battery unit's operation can be limited solely to charging. The first battery unit is one of the battery units. Furthermore, the method can advantageously be supplemented by the step of connecting a second battery unit, which differs from the first battery unit, to the low-voltage connection by closing one positive and one negative parallel switching device each belonging to the second battery unit. The second battery unit is one of the battery units.

[0022] This makes it possible to ensure the supply to the low-voltage connection via different battery systems. Each battery system can supply the low-voltage connection with the initial voltage for a period of time and then be recharged. To do this, one battery system is first disconnected from the low-voltage connection before another battery system is connected. This sequence must be followed to avoid supplying excessively high voltages to the devices connected to the low-voltage connection. This ensures a balanced load on all battery systems during a simultaneous charging / discharging process. The battery systems can be maintained in a state of charge that is as advantageous as possible with regard to degradation.

[0023] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The drawings schematically show:

[0024] Fig. 1 shows a battery system according to the invention with several battery devices in a first switch position,

[0025] Fig. 2 shows the battery system of Figure 1, wherein the low-voltage connection is supplied with electrical power,

[0026] Figure 3 shows the battery system of Figure 1, wherein the battery devices are connected in series with the charging port, and

[0027] Figure 4 shows the battery system from Figure 1 in a switch position for simultaneous charging and discharging at different voltages. Figures 1 to 4 schematically show a battery system 10, which is configured to supply a vehicle with electrical power in different switching states. When a vehicle is powered by a battery system, its total power is limited by the power of the battery system. The battery system 10 consists of four battery units 12a-12d, which, connected in parallel, provide the required system voltage, also referred to as the first voltage, for the vehicle system via the low-voltage connection 14. In the example shown, the first voltage is 48 V.

[0028] Since the low-voltage system limits not only the drive power but also the charging power, a disadvantage of known low-voltage systems is that charging the battery components of the battery system takes a very long time. To circumvent this, the battery system 10 has a charging port 16, separate from the low-voltage port 14, at which the battery components 12a-12d can be supplied with a second voltage, which serves as the charging voltage and is higher than the first voltage.

[0029] In the battery system 10, each of the battery units 12a-12d has a positive terminal 20a-20d and a negative terminal 20e-20h. Each of the positive terminals 20a-20d can be connected to the low-voltage terminal 14 via a positive parallel switching device 18a-18d. Similarly, each of the negative terminals 20e-20h can be connected to the low-voltage terminal 14 via a negative parallel switching device 18e-18h. The parallel switching devices 18e-18h are preferably designed as contactors, and particularly preferably as safety-related contactors.

[0030] To supply the low-voltage vehicle system via the low-voltage connection 14, the individual battery units 12a-12d are connected in parallel to each other as shown in Figure 2. Each of the battery units 12a-12d and the vehicle system have the same voltage. Accordingly, the battery units 12a-12d are designed by means of corresponding parallel and series connections of sub-modules or individual cells such that each of the battery units has the same low-voltage voltage of the vehicle system. The charging port 16 and consequently the charging system are not supplied in this state.

[0031] Furthermore, the battery system has 10 terminal connection lines 24a-24c. These connect a positive terminal 20a-20d of a specific battery unit 12a-12d to a negative terminal 20e-20h of a specific other battery unit 12a-12d. In the example shown, the positive terminal 20a of a first battery unit 12a is connected to the negative terminal 20f of the second battery unit 12b via the terminal connection lines 24a. A series switching device 22a, designed as a safety-oriented contactor, can electrically connect or disconnect the positive terminal 20a and the negative terminal 20f. The series switching devices 24b and 24c function similarly, so that the battery units 12a to 12d can be connected in series when the series switching devices 22a to 22c are closed, as shown in Figure 3.In this series circuit, the first battery assemblies 12a and the fourth battery assemblies 12d are end-of-line battery assemblies, since only one of their terminals is connected to a terminal connecting wire 24a, 24c. The other two terminals 20e and 20d of the end-of-line battery assemblies 12a, 12d form series terminals 26a, 26b of the series circuit, at which the sum of the voltages of battery assemblies 12a to 12d is applied. The increased voltage allows for rapid charging.

[0032] To switch between these two states, in particular high-voltage charging and low-voltage discharging, by means of an electrical signal, the battery system 10 has parallel switching devices 18a-18h and series switching devices 22a-22c. The number of series switching devices 22a-22c varies with the number of battery units 12a-12d. The series switching devices 22a-22c are preferably designed as contactors, and particularly preferably as safety-related contactors.

[0033] The parallel switching devices 18a-18h and the series switching devices can be used in this process.

[0034] Switching devices 22a-22c are assigned to the two functions of charging and discharging, with the parallel switching devices 18a-18h for realizing the parallel connection of all battery devices 12a to 12d and the series switching devices 22a-22c connecting the battery devices 12a to 12d in series and thus supplying the charging port 16.

[0035] For discharge with the first voltage to supply the vehicle system (not shown) via the low-voltage connection, the cathodes of the battery modules 12a-12d are connected to each other via the parallel switching devices 18a-18d, and their anodes via the parallel switching devices 18e-18h. The total current drawn via the low-voltage connection 14 of the battery system 10 is distributed accordingly among the individual modules.

[0036] In this state, the charging port 16 is not completely decoupled but is supplied with the low-voltage voltage. This can be avoided by decoupling the charging port 16 from the adjacent battery components 12a, 12d via two additional switching devices (not shown). In particular, a contactor (not shown) can be arranged between the charging port 16 and one or preferably both of the series-connected terminals 26a, 26b. This allows the charging port 16 to be switched without voltage when a voltage is supplied at the low-voltage terminal 14.

[0037] In the fast-charging scenario shown in Figure 3, the series switching devices 22a-22c are closed, so that the battery units 12a-12d are connected in series and the summed voltage of the individual battery units 12a-12d is present at the charging terminal 16 of the battery system 10. The low-voltage terminal 14 of the battery system 10 is de-energized in this state. Therefore, the vehicle system cannot be supplied with energy in this switching state.

[0038] To simultaneously charge with the second voltage and discharge with a low-voltage load to supply the vehicle system, the battery system 10 is operated in the switching state shown in Figure 4. In this state, the series switching devices 22a-22c are closed to connect the charging port 16 to the series connection of the battery units 12a-12d. To still provide energy via the low-voltage connection 14 during the fast charging process via the charging port 16, the battery units 12a-12d can be connected individually.

[0039] By closing one positive parallel switching device 18a and one negative parallel switching device 18e, both belonging to the first battery unit 12a, the first battery unit 12a remains in series and is charged, but at the same time is tapped via the low-voltage connection 14 and can thus supply the vehicle system with electrical energy to a small extent.

[0040] To prevent an unbalanced load from being generated in the battery system 10 during the charging process, for example, by the first battery unit 12a having a significantly lower state of charge than the remaining battery units 12b-12d, the battery units 12a-12d can be cyclically switched via the respective parallel switching devices 18a-18d. For this purpose, the first battery unit 12a is first disconnected from the low-voltage connection 14 by opening one positive parallel switching device 18a and one negative parallel switching device 18e, each belonging to the first battery unit 12a.

[0041] Subsequently, a second battery assembly 12b, which differs from the first battery assembly 12a, is connected to the low-voltage connection 14 by closing one positive parallel switching device 18b and one negative parallel switching device 18f, both of which belong to the second battery assembly 12b.

[0042] This procedure makes it possible to provide an uninterrupted power supply at the low-voltage connection 14 during charging, even when switching through the different battery devices 12a-12d.

[0043] The preceding explanations of the embodiments describe the present invention solely by way of examples. List of reference numerals

[0044] 10 battery system

[0045] 12a-d Battery system

[0046] 14 Low-voltage connection

[0047] 16 charging ports

[0048] 18a-h Parallel switching device

[0049] 20a-d positive pole

[0050] 20e-h negative pole

[0051] 22a-c series switching device

[0052] 24a-c pole connection cable

[0053] 26a, b series connection poles

Claims

Patent claims 1. Battery system (10) for providing a first voltage and for simultaneous charging with a second voltage, comprising: a plurality of battery devices (12a-12d) each with a positive terminal (20a-d) and a negative terminal (20e-h); a low-voltage connection (14) for providing the first voltage; and a charging connection (16) for charging the battery devices (12a-12d) with the second voltage, wherein each of the positive terminals (20a-d) is switchably connected to the low-voltage connection (14) via a positive parallel switching device (18a-18d) and each of the negative terminals (20e-h) is switchably connected to the low-voltage connection (14) via a negative parallel switching device (18e-18h); characterized by Pole connection lines (24a-24c) which connect the battery devices (12a-12d) to a series circuit by connecting one positive pole (20a-d) to one negative pole (20e-h) via a series switching device (22a-22c) in each case, such that two poles (20a-h) of peripheral battery devices (12a-12d) form series circuit poles (26a, 26b) of the series circuit, wherein the series circuit poles (26a, 26b) are connected to the charging terminal (16), and the series switching devices (22a-22c) and / or the parallel switching devices (18a-18h) are contactors with return lines.

2. Battery system (10) according to claim 1 , characterized in that the first voltage is lower than the second voltage.

3. Battery system (10) according to one of the preceding claims, characterized in that the first voltage is 48 V.

4. Battery system (10) according to one of the preceding claims, characterized in that the second voltage is at least 150 V.

5. Battery system (10) according to one of the preceding claims, characterized in that the battery system (10) is a vehicle battery system of a vehicle and the low-voltage connection (14) supplies at least one thermal system of the vehicle with electrical energy.

6. Method for providing a first voltage and simultaneously charging with a second voltage using a battery system (10) according to any of the preceding claims, comprising the steps: Connecting a first battery unit (12a) to the low-voltage connection (14) by closing one positive and one negative parallel switching device (18a, 18e) belonging to the first battery unit (12a); and thereby Providing the initial voltage at the low-voltage terminal (14); Closing the series switching devices (22a-22c) to connect the battery devices (12a-12d) to a series circuit with two poles (20d, 20e) of edge battery devices (12a, 12d), such that the two poles (20d, 20e) of the edge battery devices (12a, 12d) form series connection poles of the series circuit, wherein the series connection poles (26a, 26b) are connected to the charging terminal 16; and thereby Charging the battery devices (12a-12d) with the second voltage via the charging port (16).

7. The method of claim 6, further comprising the step of: Disconnecting the first battery device (12a) from the low-voltage connection (14) by opening the parallel switching device (18a, 18e) belonging to the first battery device (12a) with one positive and one negative terminal.

8. The method of claim 7, further comprising the step of: Connecting a second battery arrangement (12b), which differs from the first battery arrangement (12a), to the low-voltage connection (14) by closing one positive and one negative parallel switching device (18b, 18f) belonging to the second battery arrangement (12b).

10.

9. Electrically powered vehicle comprising a battery system (10) according to any one of claims 1 to 5.

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