Battery module for motor vehicle and motor vehicle

Abstract

The present invention relates to a battery module for a motor vehicle, the battery module comprising at least one battery cell, a negative electrode, a positive electrode, a switching unit electrically connected in series with the at least one battery cell and having at least one controllable switching element, and a management system for controlling the at least one switching element. A holding line is provided, the holding line is connected to the management system and to the switching unit in such a way that a control signal of the management system can be transmitted to the switching unit via the holding line, and the holding line is constructed in such a way that in the effective state of the holding line, a control signal of the management system for disconnecting at least one switching element can be transmitted to the switching unit with a time delay. The present invention also relates to a motor vehicle, the motor vehicle comprising a battery module according to the present invention.

Description

Technical Field

[0001] The present invention relates to a battery module for a motor vehicle, the battery module comprising at least one battery cell, a negative electrode, a positive electrode, a switching unit electrically connected in series with the at least one battery cell and having at least one controllable switching element, and a management system for controlling the at least one switching element. The present invention also relates to a motor vehicle comprising the battery module according to the present invention. Background Art

[0002] Conventional motor vehicles have a drive device, which usually includes a combustion engine. In addition, conventional motor vehicles include a battery module for supplying electrical energy to a starter and other loads of the motor vehicle, and a generator for charging the battery module. A battery module of the type described comprises a battery unit having at least one, preferably a plurality of battery cells, which are connected in series, for example, so that the battery module has a nominal voltage of, for example, 12 V, 24 V or 48 V. The battery cells are, for example, lithium-ion battery cells.

[0003] A battery module of the type described also comprises a switching unit, by means of which the battery cell can be switched on, that is, connected to the onboard electrical system of the motor vehicle, and can be switched off, that is, disconnected from the onboard electrical system. If the battery cell is switched on, the aforementioned nominal voltage provided by the battery cell is applied between the positive and negative poles of the battery module. For this purpose, the switching unit has a switching element, which is designed, for example, as an electromechanical relay or contactor and which can be opened and closed by corresponding actuation.

[0004] Furthermore, a battery module of the type described comprises a management system for monitoring the battery cells and for actuating the switching unit. By means of corresponding actuation by the management system, a switching element of the switching unit can be opened, thereby disconnecting the battery cell, and a switching element of the switching unit can be closed, thereby connecting the battery cell.

[0005] The switching unit and the management system are usually designed such that, in order to close the switching element, a corresponding control signal in the form of a control voltage is transmitted from the management system to the switching unit. As long as the control voltage is present at the switching unit, the switching element remains closed. If the control voltage at the switching unit drops, the switching element is opened.

[0006] If the management system fails briefly, for example due to a reset of a microcontroller in the management system, the control voltage at the switching unit drops. This causes the switching element to be opened, whereby the battery cell is disconnected. This means that the battery cell is disconnected from the onboard electrical system until the management system is fully operational again and the control voltage is present at the switching unit again. Summary of the invention

[0007] A battery module for a motor vehicle, in particular for a motor vehicle with a combustion engine, is proposed. The battery module comprises at least one battery unit, which preferably comprises a plurality of battery cells, which can be connected to one another both in series and in parallel within the battery unit. The battery cells are preferably designed as lithium-ion battery cells.

[0008] The battery module also includes a negative electrode and a positive electrode. When installed in a motor vehicle, that is, when connected to the onboard electrical system of the motor vehicle, the two electrodes of the battery module are electrically connected to corresponding terminals of the motor vehicle. When the battery module is operated on the onboard electrical system of the motor vehicle, a nominal voltage of, for example, 48V is applied between the electrodes.

[0009] The battery module further comprises a switching unit which is electrically connected in series with at least one battery cell. By means of the switching unit, the at least one battery cell can be electrically connected, in particular, to two poles and electrically disconnected from at least one of the poles. For this purpose, the switching unit has at least one controllable switching element.

[0010] The battery module also comprises a management system. The management system is used in particular to monitor the battery cells of the battery unit and to actuate at least one switching element of the switching unit. In order to actuate the at least one switching element, the management system transmits a corresponding actuation signal to the switching unit.

[0011] According to the invention, a holding line is provided, which is connected to the management system and to the switching unit in such a way that an actuation signal of the management system can be transmitted to the switching unit via the holding line. The holding line is designed in such a way that, in the active state of the holding line, an actuation signal of the management system for opening at least one switching element can be transmitted to the switching unit with a time delay.

[0012] According to a preferred embodiment of the invention, the holding circuit is designed such that, in the inert state of the holding circuit, an actuation signal of the management system for opening at least one switching element can be transmitted to the switching unit without delay.

[0013] According to an advantageous development of the invention, the hold circuit comprises an activation input. Here, the hold circuit can be placed in an active state by applying an activation signal to the activation input. Furthermore, the hold circuit can be placed in an inert state by applying a passivation signal to the activation input.

[0014] According to an advantageous embodiment of the invention, the holding circuit is designed in such a way that an activation signal of the management system for closing at least one switching element can be transmitted to the switching unit without delay.

[0015] Preferably, the holding circuit comprises an actuation input, which is connected to the management system and to which a control signal of the management system for opening and closing at least one switching element of the switching unit can be transmitted. Preferably, the holding circuit also comprises an actuation output, which is connected to the switching unit and from which a control signal for opening and closing at least one switching element of the switching unit can be transmitted to the switching unit. In this case, the actuation input and the actuation output of the holding circuit are preferably connected to each other by means of a diode.

[0016] According to a preferred design of the present invention, the switch unit includes a first switch element, which is configured as a MOSFET and has a first contact spacing and a first reverse diode connected in parallel with the first contact spacing. In addition, the switch unit includes a second switch element, which is also configured as a MOSFET and has a second contact spacing and a second reverse diode connected in parallel with the second contact spacing. The reverse diode, also called the body diode, is generated in each MOSFET due to its internal structure and is not a dominant component.

[0017] The switching element is preferably electrically connected in series between a first connection point and a second connection point of the switching unit such that the reverse diodes of the switching element are electrically connected in anti-series. The first connection point is connected, for example, to at least one battery cell and the second connection point is connected, for example, to the positive pole.

[0018] According to an advantageous embodiment of the invention, the two switching elements of the switching unit can be controlled independently of one another.

[0019] Preferably, the two switching elements of the switching unit are connected in such a way that a current can flow through the switching unit via the first reverse diode for charging at least one battery cell, and a current can flow through the switching unit via the second reverse diode for discharging at least one battery cell.

[0020] According to a preferred design of the present invention, the management system, the switching unit and the holding line are connected in such a way that, in an effective state of the holding line, the control signal of the management system for disconnecting the first switching element can be transmitted to the switching unit with a time delay, and the control signal of the management system for disconnecting the second switching element can be transmitted to the switching unit without delay.

[0021] A motor vehicle is also provided. The motor vehicle according to the invention comprises at least one battery module according to the invention.

[0022] The advantage of the present invention is that in the battery module according to the present invention, the control signal of the management system in the form of a control voltage can be maintained during the duration of the time delay. When the control voltage on the management system drops for a short time, the control voltage on the switching unit is still maintained during the time delay. If the duration of the time delay is greater than or equal to the duration required for the microcontroller of the management system to reset, the control voltage on the switching unit is maintained in particular during the reset of the microcontroller. As a result, the switching element of the switching unit remains closed during the reset of the microcontroller and the battery cell remains connected. As a result, the onboard electrical system of the motor vehicle can continue to be supplied with voltage via the poles of the battery module. In particular, the safety-related components of the motor vehicle that are connected to the onboard electrical system remain continuously available and do not fail for a short time during the reset of the microcontroller.

[0023] If the holding circuit is operated in an idling operating state, in which the control voltage of the management system is transmitted to the switching unit without delay, a self-test of the battery module can also be performed. In particular, the functionality of the switching unit and the switching elements can be tested during a self-test of the safety-related disconnection paths of the battery module.

[0024] If the switching unit has two reverse diodes designed as MOSFETs and connected in series, the currents for charging and discharging the battery cells can be controlled individually. In particular, during the reset of the microcontroller, the current for discharging the battery cells can be enabled, thereby continuing to ensure the supply of the onboard electrical system. At the same time, during the reset of the microcontroller, the current for charging the battery cells can be prevented, thereby ensuring the intrinsic safety of the battery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Embodiments of the invention are explained in more detail with the aid of the drawings and the following description.

[0026] Figure 1 shows a schematic diagram of a battery module;

[0027] Figure 2 A schematic diagram of a holding circuit is shown; and

[0028] Figure 3 A schematic diagram of a switch unit is shown. DETAILED DESCRIPTION

[0029] In the following description of embodiments of the invention, identical or similar elements are denoted by the same reference numerals, wherein a repeated description of these elements is omitted in individual cases. The figures merely schematically illustrate the subject matter of the invention.

[0030] Figure 1 A schematic diagram of a battery module 5 for a motor vehicle is shown. The battery module 5 comprises a battery unit 2 with a plurality of battery cells connected in series. The battery cells are designed as lithium-ion battery cells. The battery cells 2 are arranged electrically between a positive terminal 12 and a negative terminal 11.

[0031] The voltage of, for example, 48 V provided by the battery cells of the battery unit 2 is therefore applied between the positive terminal 12 and the negative terminal 11. The battery module 5 also includes a negative electrode 21 and a positive electrode 22. The negative terminal 11 is electrically connected to the negative electrode 21.

[0032] The battery module 5 is connected to the onboard electrical system of the motor vehicle (not shown here). If a charging current flows from the positive pole 22 through the battery cell 2 to the negative pole 21, the battery cell of the battery cell 2 is charged. If a discharging current flows from the negative pole 21 through the battery cell 2 to the positive pole 22, the battery cell of the battery cell 2 is discharged.

[0033] The battery module 5 includes a switch unit 60. The switch unit 60 has a first connection point 65 and a second connection point 66. The first connection point 65 of the switch unit 60 is electrically connected to the positive terminal 12. The second connection point 66 of the switch unit 60 is electrically connected to the positive electrode 22. Therefore, the switch unit 60 is electrically connected in series between the positive electrode 22 and the positive terminal 12. Thus, the switch unit 60 is electrically connected in series between the electrodes 21 and 22 relative to the battery cell 2.

[0034] The battery module 5 also comprises a management system 30 for controlling and monitoring the battery cells of the battery unit 2. The management system 30 is also used to control a switching unit 60. In particular, the management system 30 is used to actuate at least one switching element 61, 62 (not shown here) of the switching unit 60.

[0035] Furthermore, the battery module 5 comprises a holding circuit 40. The holding circuit 40 comprises an activation input 44. The holding circuit 40 can be placed in an active state by applying an activation signal to the activation input 44. The holding circuit 40 can be placed in an inactive state by applying a passivation signal to the activation input 44. The activation input 44 is connected to the management system 30.

[0036] The hold circuit 40 comprises an actuation input 41 connected to the control system 30 and an actuation output 42 connected to the first control input 75 of the switching unit 60. The actuation signal of the control system 30 for opening and for closing the first switching element 61 of the switching unit 60 is transmitted by the control system 30 to the actuation input 41 of the hold circuit 40.

[0037] If the hold line 40 is in the active state, an activation signal for opening the first switching element 61 of the switching unit 60 can be transmitted with a time delay from the activation output 42 of the hold line 40 to the first control input 75 of the switching unit 60 .

[0038] If the holding line 40 is in the inert state, an actuation signal for switching off the first switching element 61 of the switching unit 60 can be transmitted without delay from the actuation output 42 of the holding line 40 to the first control input 75 of the switching unit 60 .

[0039] The control signal of management system 30 for closing first switching element 61 of switching unit 60 is always transmitted here, ie, without delay, from control output 42 of hold line 40 to first control input 75 of switching unit 60 , ie, independently of the state of hold line 40 .

[0040] The second control input 76 of the switching unit 60 is connected to the management system 30. The control signal of the management system 30 for opening and closing the second switching element 62 of the switching unit 60 is immediately transmitted by the management system 30 to the second control input 76 of the switching unit 60. The control signal of the management system 30 for opening and closing the second switching element 62 is thus transmitted to the switching unit 60 without delay and independently of the holding line 40.

[0041] Figure 2 The schematic diagram of a holding circuit 40 is shown. As already mentioned, the holding circuit 40 comprises an actuation input 41, an actuation output 42 and an activation input 44. The actuation input 41 and the actuation output 42 of the holding circuit 40 are connected to one another by means of a diode 43.

[0042] The holding circuit 40 includes a first semiconductor switch T1, a second semiconductor switch T2 and a third semiconductor switch T3. The semiconductor switches T1, T2, T3 are each configured as a MOSFET. The semiconductor switches T1, T3 are configured as n-channel MOSFETs, and the semiconductor switch T2 is configured as a p-channel MOSFET.

[0043] The gate terminal of the first semiconductor switch T1 is connected to the activation input 44. The gate terminal of the first semiconductor switch T1 is also connected via a pull-up resistor RP to a first voltage source V1 which provides a voltage of 5V, for example.

[0044] The source terminal of the first semiconductor switch T1 is connected to ground. The drain terminal of the first semiconductor switch T1 is connected to a second voltage source V2 that provides a voltage of 12V, for example, via a series connection formed by a first resistor R1 and a second resistor R2.

[0045] A gate terminal of the second semiconductor switch T2 is connected to a first node K1 between the first resistor R1 and the second resistor R2 .

[0046] The source terminal of the second semiconductor switch T2 is connected to the second voltage source V2. The drain terminal of the second semiconductor switch T2 is connected to ground via a series connection formed by a third resistor R3 and a fourth resistor R4.

[0047] A gate terminal of the third semiconductor switch T3 is connected to a second node K2 which is located between the third resistor R3 and the fourth resistor R4.

[0048] A source terminal of the third semiconductor switch T3 is connected to the control output 42 and to the diode 43. A drain terminal of the third semiconductor switch T3 is connected to ground via a parallel connection formed by an output resistor RA and an output capacitor CA.

[0049] If the activation input 44 is connected to ground, the hold line 40 is deactivated and the signal at the control output 42 is not held.

[0050] If a voltage of, for example, 5 V is present at activation input 44, then hold circuit 40 is activated and the signal at control output 42 is held. The time delay is dependent on the values ​​of output capacitor CA and output resistor RA.

[0051] If the activation input 44 is actuated with high impedance, which occurs when the microcontroller in the management system 30 is reset, the voltage at the gate terminal of the first semiconductor switch T1 is pulled via the pull-up resistor RP to a voltage of, for example, 5 V. As a result, the hold line 40 is activated and the signal at the actuation output 42 is held.

[0052] Figure 3 The schematic diagram of the switching unit 60 is shown. The switching unit 60 has in particular a first switching element 61 and a second switching element 62. The first switching element 61 and the second switching element 62 are connected electrically in series between a first connection point 65 and a second connection point 66 of the switching unit 60.

[0053] The first switching element 61 is designed as a MOSFET. The first switching element 61 has a controllable first contact gap 71 and a first reverse diode 73. The first reverse diode 73 is connected electrically in parallel with the controllable first contact gap 71. The first reverse diode 73, also referred to as a body diode, is conductive for a through current in one direction and blocks a through current in the opposite direction.

[0054] The second switching element 62 is designed as a MOSFET. The second switching element 62 has a controllable second contact gap 72 and a second reverse diode 74. The second reverse diode 74, also called a body diode, is connected electrically in parallel with the controllable second contact gap 72. The second reverse diode 74 is conductive for a through current in one direction and blocks a through current in the opposite direction.

[0055] The two switching elements 61, 62 are arranged inside the switching unit 60 in such a way that the two reverse diodes 73, 74 are electrically connected in anti-series. Figure 1 In the arrangement of the battery module 5 shown, a through current for charging the battery cell 2 can be generated through the first reverse diode 73 and a through current for discharging the battery cell 2 can be generated through the switch unit 60 .

[0056] A first control input 75 of the switching unit 60 is connected to a gate terminal (not shown here) of a first switching element 61 designed as a MOSFET, and the first contact gap 71 can be controlled by applying a corresponding signal to the first control input 75 .

[0057] A second control input 76 of the switching unit 60 is connected to a gate terminal (not shown here) of a second switching element 62 designed as a MOSFET, and the second contact gap 72 can be controlled by applying a corresponding signal to the second control input 76 .

[0058] The two switching elements 61 , 62 can thus be controlled independently of one another by applying corresponding signals to the two control inputs 75 , 76 of the switching unit 60 .

[0059] The invention is not limited to the embodiments described here and the aspects emphasized therein. Rather, within the scope of the claims, numerous modifications are possible which are within the purview of a person skilled in the art.

Claims

1. A battery module (5) for a motor vehicle, comprising: at least one battery cell (2); A negative electrode (21), a positive electrode (22); a switching unit (60) which is electrically connected in series with the at least one battery cell (2) and has at least one controllable switching element (61, 62); as well as a management system (30) for controlling the at least one switching element (61, 62); It is characterized in that A holding line (40) is provided, which is connected to the management system (30) and to the switch unit (60) in such a way that a control signal of the management system (30) can be transmitted to the switch unit (60) via the holding line (40); and The holding circuit is designed such that, in an effective state of the holding circuit (40), a control signal of the management system (30) for disconnecting the at least one switching element (61, 62) can be transmitted to the switching unit (60) with a time delay, wherein the holding line (40) is designed such that in an inert state of the holding line (40), an actuation signal of the management system (30) for disconnecting the at least one switching element (61, 62) can be transmitted to the switching unit (60) without delay, The holding circuit (40) comprises an activation input (44), wherein the holding circuit (40) can be placed in an active state by applying an activation signal to the activation input (44), and wherein the holding circuit (40) can be placed in an inactive state by applying a deactivation signal to the activation input (44), If the activation input (44) is connected to ground, the hold line (40) is deactivated and the signal at the control output (42) is not held.

2. The battery module (5) according to claim 1, characterized in that: The holding line (40) is designed in such a way that an actuation signal of the management system (30) for closing the at least one switching element (61, 62) can be transmitted to the switching unit (60) without delay.

3. The battery module (5) according to claim 1 or 2, characterized in that: The holding circuit (40) comprises: a control input terminal (41), the control input terminal being connected to the management system (30) and capable of transmitting a control signal of the management system (30) to the control input terminal; and a control output terminal (42), the control output terminal being connected to the switch unit (60) and capable of transmitting a control signal from the control output terminal to the switch unit (60). The control input (41) and the control output (42) are connected to one another by means of a diode (43).

4. The battery module (5) according to claim 1 or 2, characterized in that: The switch unit (60) comprises: a first switch element (61), which is configured as a MOSFET and has a first contact gap (71) and a first reverse diode (73) connected in parallel with the first contact gap (71); and a second switch element (62), which is configured as a MOSFET and has a second contact gap (72) and a second reverse diode (74) connected in parallel with the second contact gap (72), wherein The switching elements (61, 62) are electrically connected in series between a first connection point (65) and a second connection point (66) such that the reverse diodes (73, 74) of the switching elements (61, 62) are electrically connected in anti-series.

5. The battery module (5) according to claim 4, characterized in that: The switching elements (61, 62) can be controlled independently of one another.

6. The battery module (5) according to claim 4, characterized in that: The switching elements (61, 62) are connected in such a way that a current can flow through the switching unit (60) for charging the at least one battery cell (2) via the first reverse diode (73), and a current can flow through the switching unit (60) for discharging the at least one battery cell (2) via the second reverse diode (74).

7. The battery module (5) according to claim 4, characterized in that: The management system (30), the switch unit (60) and the holding line (40) are connected in such a way that, in an active state of the holding line (40), a control signal of the management system (30) for disconnecting a first switch element (61) can be transmitted to the switch unit (60) with a time delay, and a control signal of the management system (30) for disconnecting a second switch element (62) can be transmitted to the switch unit (60) without delay.

8. A motor vehicle comprising at least one battery module (5) according to any one of claims 1 to 7.

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