Battery pack system for use in the on-board electrical network of a motor vehicle

Abstract

A battery system for use on an onboard power system of a motor vehicle. The invention relates to a battery system (10) for use on an onboard power system (50) of a motor vehicle, the battery system comprising a negative electrode (21), a positive electrode (22), a battery module (5), and a switching unit (60), the switching unit having at least one controllable switch and a current sensor (65) for measuring a battery current (IB) flowing through the battery system (10). The switching unit (60) can be operated in a safety mode, in which the at least one switch and the current sensor (65) act together so that when the battery current (IB) exceeds a predetermined limit value, the battery current (IB) is limited to a predetermined maximum value or interrupted for a predetermined maximum time period, thereby preventing the motor vehicle from being started.

Description

Technical Field

[0001] The invention relates to a battery system for use on an onboard electrical system of a motor vehicle, comprising a negative pole, a positive pole, a battery module and a switching unit having at least one controllable switch and a current sensor for measuring a battery current flowing through the battery system. Background Art

[0002] Conventional motor vehicles have a drive system that typically includes an internal combustion engine. They also include a battery system for supplying electrical energy to a starter and other electrical consumers on the vehicle's onboard electrical system, and a generator for supplying power to the battery system. Such a battery system includes at least one battery module and a switching unit, which can be used to switch the battery module on and off. The battery module includes a plurality of battery cells, for example, including lithium-ion cells. A management system is also provided for controlling and monitoring the battery cells of the battery module.

[0003] Especially valuable motor vehicles are relatively frequently stolen. Therefore, modern motor vehicles are often equipped with anti-theft devices, which are intended to prevent theft of the vehicle or at least make it more difficult. Anti-theft devices for retrofitting into motor vehicles are also known.

[0004] EP 0 161 365 A2 discloses an anti-theft device for a vehicle, comprising a switch that can be used to disconnect a battery pack from the vehicle. In particular, the battery pack is disconnected from the vehicle when the current flowing through the battery pack cable exceeds a predetermined limit value. The predetermined limit value corresponds to a starting current requirement of the starter that is just insufficient to start the vehicle. The anti-theft device can be activated and deactivated by remote control.

[0005] Document DE 10 2016 223 734 A1 discloses a vehicle with a hydraulic brake system, wherein the brake system is integrated into an anti-theft system. In the activated operating state, the brake system is disengaged and movement of the vehicle's wheels is possible. In the blocked operating state, the brake system is locked and movement of the wheels is prevented. A control unit is provided to control the state. Using an authentication unit, such as a Bluetooth unit, the blocking of the brake system can be unblocked by means of a corresponding radio signal. In particular, the anti-theft system is automatically activated if the vehicle has not been moved for a predetermined period of time, such as 10 minutes.

[0006] Document DE 10 2011 013 182 A1 discloses a safety battery pack for electric vehicles. Here, the battery cells of the battery pack are interconnected in groups. The groups of battery cells are connected to each other via a plurality of switchable isolating elements. These groups of battery cells can be separated from each other using a control command. The traction battery pack can be deactivated using a corresponding radio signal, thereby stopping the vehicle (KFZ) drive. This anti-theft device can be activated and deactivated using a wireless communication device, such as a mobile phone, particularly based on Bluetooth.

[0007] Anti-theft devices for motor vehicles are also known that use a switch to disconnect the battery pack from the onboard electrical system of the motor vehicle. Such anti-theft devices can be activated and deactivated by radio signals, such as those from a mobile phone. Summary of the Invention

[0008] A battery system for use in an onboard electrical system of a motor vehicle is disclosed. The battery system includes a negative electrode, a positive electrode, and a battery module. The battery module has a plurality of battery cells that can be connected in series or in parallel within the battery module. The battery module also includes a negative terminal and a positive terminal. The voltage provided by the battery cells of the battery module is applied between the negative terminal and the positive terminal. During normal operation of the battery system, the voltage provided by the battery module is also applied between the negative electrode and the positive electrode as an output voltage.

[0009] The battery system further includes a switching unit having at least one controllable switch and a current sensor for measuring a battery current flowing through the battery system. The switch is, for example, a semiconductor switch, in particular a MOSFET transistor. However, the switch may also be, for example, a controllable relay. In this case, the battery current flows, in particular, through the negative electrode of the battery system and / or through the positive electrode of the battery system.

[0010] According to the present invention, the switching unit can operate in a safety mode, in which the at least one switch and the current sensor work together so that when the battery pack current exceeds a predetermined limit value, the battery pack current is limited to a predetermined maximum value, or the battery pack current is interrupted for a predetermined maximum time period.

[0011] If the switching unit is operated in safety mode, theft of the motor vehicle is significantly more difficult. In particular, starting the motor vehicle's internal combustion engine using the motor vehicle's starter is prevented. The switching unit can also be operated in driving mode, in which the motor vehicle's internal combustion engine can be started using the starter.

[0012] The predetermined limit value is lower than the starting current required by the starter of the motor vehicle to start the internal combustion engine. The predetermined limit value is, for example, in the order of magnitude of between 400A and 700A.

[0013] Preferably, as soon as the current sensor measures a battery current that exceeds a predetermined limit value, the battery current is immediately limited or interrupted, i.e., without delay. However, it is also conceivable that the battery current is limited or interrupted only if the current sensor measures a battery current that exceeds a predetermined limit value within a period of, for example, 50 ms or 100 ms.

[0014] The predetermined maximum value corresponds to a current that is lower than the starting current required by the starter of the motor vehicle to start the internal combustion engine. Thus, by limiting the battery current to the maximum value, starting the internal combustion engine by the starter is prevented.

[0015] A brief interruption of the battery current can be achieved by briefly disconnecting the output voltage provided by the battery system from the onboard electrical system. The predetermined maximum time period is preferably less than the time during which other electrical consumers connected to the onboard electrical system of the motor vehicle, such as a control unit, can remain switched on without an external voltage supply. Consequently, the aforementioned electrical consumers are not switched off due to the brief interruption of the battery current.

[0016] According to an advantageous embodiment of the present invention, the switching unit includes a first switch through which the battery current flows when the first switch is closed. The first switch can be controlled so that the battery current is interrupted for a predetermined duration that is less than or equal to a maximum time period by opening the first switch. If the first switch is opened, the output voltage is also disconnected.

[0017] After a predetermined time period, the first switch is preferably closed again to re-ensure the voltage supply to other electrical consumers, such as a control unit. It is also conceivable to operate the first switch in a time-controlled manner. This means that the first switch is opened and closed multiple times within a predetermined time period that is less than or equal to the maximum time period.

[0018] According to another advantageous embodiment of the present invention, the switching unit includes a second switch electrically connected in parallel with a current-limiting resistor. The switching unit is designed so that the battery current flows through the current-limiting resistor when the second switch is open. The battery current generates a voltage drop across the current-limiting resistor. This reduces the output voltage of the battery system and limits the battery current.

[0019] According to another advantageous embodiment of the present invention, the switching unit includes a third switch electrically connected in series with a heating resistor. The heating resistor is used, in particular, to heat the battery cells of the battery module at low temperatures. The switching unit is designed so that when the third switch is closed, a heating current flows through the heating resistor. This heating current generates a voltage drop across the heating resistor and across the internal resistance of the battery module. This reduces the output voltage of the battery system and limits the battery current.

[0020] According to an advantageous embodiment of the present invention, the battery system includes an auxiliary pole that is electrically connected to the battery module, bypassing the switching unit. When used in a motor vehicle, the positive pole of the battery system is preferably electrically connected to the starter, while the auxiliary pole is electrically connected to the remaining connected electrical consumers, such as a control unit. In this case, interrupting or limiting the battery current by means of the switching unit has a reduced impact on the voltage supply to the remaining connected electrical consumers, such as the control unit.

[0021] According to an advantageous embodiment of the present invention, the battery system includes at least one further switch. This at least one further switch can be used to disconnect individual battery cells of a battery module. If, for example, battery cells within a battery module are connected in series, the at least one further switch can be used to bridge and bypass individual battery cells. This reduces the voltage supplied by the battery module and the output voltage of the battery system accordingly. This reduces the current that can be supplied by the battery module to below the limit value required for starting the vehicle via the starter.

[0022] Advantageously, the switching unit includes a control unit that can be used to switch the switching unit into a safety mode and a driving mode in which the internal combustion engine of the motor vehicle can be started using the starter. In driving mode, the battery current is not limited or interrupted, in particular when the battery current exceeds a predetermined limit value. For this purpose, the control unit includes, for example, a microcontroller.

[0023] Preferably, the switch unit has a communication unit, through which at least one control signal for switching the switch unit into the safety mode and the driving mode can be received and transmitted to the control unit.

[0024] The communication unit is preferably designed as a wireless radio interface, such as WLAN or Bluetooth. Advantageously, the at least one control signal for switching the switching unit can be sent by a mobile phone.

[0025] According to one possible embodiment of the present invention, when and as long as the communication unit receives a control signal, the control unit switches the switch unit to driving mode. If the communication unit does not receive a corresponding control signal within a predetermined time interval, the control unit switches the switch unit to safety mode. For example, the vehicle owner's mobile phone transmits the control signal at regular intervals. If the owner, carrying the mobile phone, is near the vehicle, the communication unit receives the control signal and switches the switch unit to driving mode. If the owner, carrying the mobile phone, moves away from the vehicle, the communication unit no longer receives the control signal, and the switch unit automatically switches to safety mode.

[0026] The battery system according to the present invention is advantageously used in the onboard electrical system of a motor vehicle, in particular a motor vehicle with an internal combustion engine. However, other applications are also encompassed, such as use in the onboard electrical system of other motor vehicles, such as hybrid vehicles and plug-in hybrid vehicles, in which the internal combustion engine is started by the battery system.

[0027] Advantages of the present invention

[0028] The battery system in a motor vehicle according to the present invention significantly makes motor vehicle theft more difficult. By limiting and / or interrupting the battery current, starting the vehicle's internal combustion engine via the vehicle's starter is reliably prevented. Furthermore, the battery system in a motor vehicle according to the present invention allows other electrical consumers connected to the vehicle's onboard electrical system, such as control units, to remain connected. Consequently, these consumers are not shut down due to the limiting and / or interrupting the battery current. This allows compliance with key automotive industry standards, particularly the ASIL requirements according to ISO 26262. The battery system according to the present invention can be operated particularly conveniently by the vehicle user, for example, using a mobile phone. Furthermore, the battery system according to the present invention can also be automatically switched into a safety mode (in which anti-theft is activated) and a driving mode (in which anti-theft is deactivated), for example, using a mobile phone. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Embodiments of the present invention are further explained with reference to the drawings and the following description.

[0030] in:

[0031] Figure 1 A schematic diagram of a battery system on an onboard electrical system of a motor vehicle is shown;

[0032] Figure 2 shows a schematic diagram of a switching unit according to a first embodiment;

[0033] Figure 3 shows a schematic diagram of a switching unit according to a second embodiment;

[0034] Figure 4 shows a schematic diagram of a switching unit according to a third embodiment;

[0035] Figure 5 A schematic diagram of a battery system according to an alternative embodiment is shown on the onboard electrical system of a motor vehicle; and

[0036] Figure 6 A schematic diagram of a method for operating a battery system on an onboard electrical system of a motor vehicle is shown. DETAILED DESCRIPTION

[0037] In the following description of the embodiments of the present invention, identical or similar elements are denoted by identical reference numerals, wherein repeated description of these elements is omitted in individual cases. The drawings merely schematically present the subject matter of the present invention.

[0038] Figure 1 A schematic diagram shows a battery system 10 on an onboard electrical system 50 of a motor vehicle (not shown here). In this context, the energized power supply line in a motor vehicle is referred to as onboard electrical system 50. In the present case, onboard electrical system 50 has a nominal voltage of 12 volts relative to ground 55 in the motor vehicle. Onboard electrical system 50 can also have other nominal voltages, for example, 24 volts or 48 volts. In particular, a starter (not shown here) for starting the internal combustion engine of the motor vehicle is connected to onboard electrical system 50.

[0039] The battery system 10 includes a positive terminal 22, which is connected to the vehicle electrical system 50. The battery system 10 also includes a negative terminal 21, which is connected to ground 55. The battery system 10 includes a battery module 5 having a plurality of battery cells, which are embodied as lithium-ion batteries, for example. These battery cells are connected in series, for example, and provide a nominal voltage of, for example, 12 volts. The battery module 5 includes a negative terminal 11 and a positive terminal 12. The nominal voltage of 12 volts provided by the battery cells is applied between the terminals 11, 12 of the battery module 5.

[0040] The battery module 5 is arranged in a housing 24. A negative electrode 21 and a positive electrode 22 extend from the housing 24. The negative terminal 11 is electrically connected to the negative electrode 21. During normal operation, if the positive terminal 12 is electrically connected to the positive electrode 22, the nominal voltage of 12 volts provided by the battery cells of the battery module 5 is also applied between the electrodes 21 and 22 as the output voltage.

[0041] The battery system 10 further includes a switching unit 60. The switching unit 60 has a first connection 31, which is electrically connected to the positive terminal 12. The switching unit 60 also has a second connection 32, which is electrically connected to the positive terminal 22. In the present case, the switching unit 60 is also located within the housing 24. During normal operation, the nominal voltage provided by the battery module 5, for example, 12 volts, is applied to the first connection 31.

[0042] The switching unit 60 includes a current sensor 65 for measuring a battery current IB flowing through the battery system 10. In this case, the battery current IB flows in particular through the negative pole 21 of the battery system 10 and / or through the positive pole 22 of the battery system 10.

[0043] Switching unit 60 includes a control unit 66, which can be used to switch switching unit 60 between a safety mode and a driving mode. For this purpose, control unit 66 includes, for example, a microcontroller. In driving mode, the internal combustion engine of the motor vehicle can be started using a starter. In safety mode, starting the internal combustion engine using the starter is prevented.

[0044] Switching unit 60 includes a communication unit 69. In the present case, communication unit 69 is implemented as a wireless radio interface, such as WLAN or Bluetooth. At least one control signal for switching switching unit 60 into a safety mode and a driving mode can be received via communication unit 69 and transmitted to control unit 66.

[0045] Figure 2 A schematic diagram of a switching unit 60 according to a first embodiment is shown. The switching unit 60 includes a first switch 61, which is electrically connected to the first terminal 31 and the second terminal 32. If the first switch 61 is closed, the battery current IB flows through the first switch 61. If the first switch 61 is open, the electrical connection between the positive pole 22 and the positive terminal 12 is interrupted, thereby disconnecting the output voltage.

[0046] Figure 3 A schematic diagram of a switching unit 60 according to a second embodiment is shown. The switching unit 60 includes a second switch 62 and a current-limiting resistor 67. The second switch 62 is electrically connected to the first terminal 31 and the second terminal 32. The current-limiting resistor 67 is electrically connected in parallel with the second switch 62. If the second switch 62 is closed, the battery current IB flows through the second switch 62. If the second switch 62 is open, the battery current IB flows through the current-limiting resistor 67, generating a voltage drop across the current-limiting resistor 67. As a result, the output voltage of the battery system 10 decreases.

[0047] Figure 4A schematic diagram of a switching unit 60 according to a third embodiment is shown. The first terminal 31 is directly electrically connected to the second terminal 32 via a connecting line. The switching unit 60 includes a third switch 63 and a heating resistor 68. The third switch 63 is electrically connected to the connecting line and is connected in series with the heating resistor 68. The heating resistor 68 is grounded via the negative pole 21 (not shown here) and is used, in particular, to heat the battery cells of the battery module 5 at low temperatures.

[0048] If the third switch 63 is closed, a heating current IH flows through the third switch 63 and through the heating resistor 68. The heating current IH generates a voltage drop across the heating resistor 68 and across the internal resistance (not shown here) of the battery module 5. As a result, the output voltage of the battery system 10 decreases.

[0049] Figure 5 A schematic diagram of a battery system 10 according to an alternative embodiment is shown on an onboard electrical system 50 of a motor vehicle. The battery system 10 according to this alternative embodiment is connected to the onboard electrical system 50 of a motor vehicle. Figure 1 The battery systems 10 shown in FIG. 1 are designed to be largely identical. The differences are discussed below.

[0050] The battery system 10 according to this alternative embodiment includes an auxiliary pole 23 that protrudes from a housing 24. The auxiliary pole 23 is electrically connected to the positive terminal 12. Thus, the auxiliary pole 23 is electrically connected to the battery module 5 while bypassing the switching unit 60. During normal operation, the nominal voltage of, for example, 12 volts, provided by the battery cells of the battery module 5, is also present between the auxiliary pole 23 and the negative pole 21. In a motor vehicle, the positive pole 22 is electrically connected to the starter. The auxiliary pole 23 is electrically connected to the remaining connected electrical consumers, such as a control unit.

[0051] Figure 6 A schematic diagram of a method for operating a battery system 10 on an onboard electrical system 50 of a motor vehicle is shown. In an initial step 101, the motor vehicle is stopped and the internal combustion engine is switched off.

[0052] Then, in the following step 102, a check is performed to determine whether the switch unit 60 is switched to a driving mode in which the internal combustion engine of the motor vehicle can be started by means of a starter, or whether the switch unit 60 is switched to a safety mode in which starting of the internal combustion engine by means of a starter is prevented. If the switch unit 60 is switched to the driving mode, the method ends in a final step 110.

[0053] If the switching unit 60 is switched to the safety mode, in a subsequent step 103 the battery current IB is measured and monitored by means of the current sensor 65. If the battery current IB is below a predetermined limit value or equal to a predetermined limit value, the method ends in a further final step 110.

[0054] If the battery current IB exceeds a predetermined limit value, the battery current IB is limited to a predetermined maximum value or interrupted for a predetermined maximum time period in the following step 104. This prevents starting the internal combustion engine of the motor vehicle by means of the starter.

[0055] In the following step 105, the vehicle owner is informed that an attempt has been made to start the vehicle's internal combustion engine using the starter, and that the switch unit 60 has been switched to a safety mode. This information is transmitted, for example, by the communication unit 69 of the battery system 10 to the vehicle owner's mobile phone. This information can also be displayed in the vehicle's cockpit.

[0056] The invention is not limited to the embodiments described herein and the aspects highlighted therein. Rather, within the scope of protection indicated by the claims, numerous variations are possible, which are within the purview of a person skilled in the art.

Claims

1. A battery system (10) for use on an onboard electrical system (50) of a motor vehicle, the battery system comprising: A negative electrode (21), a positive electrode (22), a battery module (5), and a switching unit (60), the switching unit having at least one controllable switch and a current sensor (65) for measuring a battery current flowing through the battery system (10), It is characterized in that The switch unit (60) is capable of operating in a safety mode, in which the at least one switch and the current sensor (65) function together so that When the battery current exceeds a predetermined limit value, the battery current A predetermined maximum time period is interrupted, wherein the predetermined maximum time period is less than the time during which other electrical consumers connected to the onboard electrical system of the motor vehicle can remain switched on without an external voltage supply.

2. The battery system (10) according to claim 1, characterized in that The switch unit (60) has a first switch (61), the battery current flows through the first switch (61), and the first switch (61) can be controlled so that The battery current is interrupted for a predetermined duration that is less than or equal to the maximum time period.

3. The battery system (10) according to claim 1 or 2, characterized in that: The battery system (10) comprises an auxiliary pole (23) which is electrically connected to the battery module (5) while bypassing the switching unit (60).

4. The battery system (10) according to claim 1 or 2, characterized in that: The switch unit (60) has a control unit (66), by means of which the switch unit (60) can be switched to the safety mode and the driving mode, in which the If the battery current exceeds the predefined limit value, no interruption of the battery current is provided.

5. The battery system (10) according to claim 4, characterized in that The switch unit (60) has a communication unit (69) through which at least one control signal for switching the switch unit (60) to the safety mode and the driving mode can be received and the at least one control signal can be transmitted to the control unit (66).

6. The battery system (10) according to claim 5, characterized in that The communication unit (69) is designed as a wireless radio interface.

7. The battery system (10) according to claim 5, characterized in that If the communication unit (69) receives a control signal, the control unit (66) switches the switch unit (60) to the driving mode; and if the communication unit (69) does not receive a control signal within a predetermined time interval, the control unit (66) switches the switch unit (60) to the safety mode.

8. Use of the battery system (10) according to any one of claims 1 to 7 in an onboard electrical system (50) of a motor vehicle.

9. The use according to claim 8, wherein: The motor vehicle is a motor vehicle having an internal combustion engine.

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