ASSEMBLY FOR SWITCHING A HIGH-VOLTAGE BATTERY IN A VEHICLE

Abstract

The invention relates to a circuit assembly, to a system and to a method for switching a high-voltage battery (201) and to a vehicle having such a circuit assembly and such a system. The circuit assembly comprises a transistor for conducting a current from the battery (201) to a load and comprises a diode (202) for conducting a return current into the battery (201). The circuit assembly is configured to provide a pre-charging current by means of the pulsed switching of the transistor (203).

Claims

1. A circuit assembly for switching a high-voltage battery (201), having: a precharging circuit (204) configured for connection to a first terminal of the high-voltage battery (201) and for precharging a consumer, the consumer having a transistor (203) for conducting a current from the battery (201) to the consumer and a diode (202) arranged back-to-back in parallel with the transistor for conducting a return current into the battery (201).

2. The circuit assembly as claimed in claim 1, wherein the transistor (203) is a silicon carbide MOSFET semiconductor, and the diode (202) is integrated in the silicon carbide MOSFET semiconductor (203).

3. The circuit assembly as claimed in claim 1, wherein the transistor (203) is configured to switch in pulsed fashion on connection of the battery (201) during a precharging phase.

4. The circuit assembly as claimed in claim 1, further having: a relay (205), designed for connection to a second terminal of the high-voltage battery (201).

5. A system (201, 204, 206) for switching a high-voltage battery (201), having: a circuit assembly as claimed in claim 1, a high-voltage battery (201), and a consumer circuit (206), wherein the first terminal of the high-voltage battery (201) is connectable to the precharging circuit (204), the precharging circuit (204) is connectable to a positive line of the consumer circuit (206), and wherein the consumer circuit (206) has capacitive properties.

6. The system (201, 204, 206) as claimed in claim 5, wherein the second terminal of the high-voltage battery (201) is connectable to a relay (205), and the relay (205) is connectable to a negative line of the consumer circuit (206).

7. A motor vehicle (500), having a circuit assembly comprising: a precharging circuit (204) configured for connection to a first terminal of the high-voltage battery (201) and for precharging a consumer, the consumer having a transistor (203) for conducting a current from the battery (201) to the consumer and a diode (202) arranged back-to-back in parallel with the transistor for conducting a return current into the battery (201).

8. A method (301, 302) for connecting a high-voltage battery (201) to a consumer circuit (206) in a motor vehicle (500) by means of a circuit assembly having a precharging circuit (204) configured for connection to a first terminal of the high-voltage battery (201) and for precharging a consumer, the consumer having a transistor (203) for conducting a current from the battery (201) to the consumer and a diode (202) arranged back-to-back in parallel with the transistor for conducting a return current into the battery (201), the method comprising: in a first phase (301), during the connection, switching the transistor (203) in pulsed fashion, and, in a second phase (302), during the connection, switching the transistor (203) on.

9. The method (301, 302) as claimed in claim 8, wherein the first phase (301) is concluded when the consumer (206) is approximately or completely charged.

10. A method (401) for disconnecting a high-voltage battery (201) in a motor vehicle (500) having a circuit assembly having a precharging circuit (204) configured for connection to a first terminal of the high-voltage battery (201) and for precharging a consumer, the consumer having a transistor (203) for conducting a current from the battery (201) to the consumer and a diode (202) arranged back-to-back in parallel with the transistor for conducting a return current into the battery (201), wherein the transistor (203) is turned off, and a return current is conducted via the diode (202) to the battery (201).

Description

[0022] Exemplary embodiments of the invention are illustrated in the drawings and will be explained in more detail in the description below. In the drawings:

[0023] FIG. 1 shows a circuit assembly for connecting and disconnecting a high-voltage battery,

[0024] FIG. 2 shows a circuit assembly and a system for connecting and disconnecting a high-voltage battery in accordance with one exemplary embodiment,

[0025] FIG. 3 shows a block circuit diagram of a method for connecting a high-voltage battery in accordance with one exemplary embodiment,

[0026] FIG. 4 shows a block circuit diagram of a method for disconnecting a high-voltage battery in accordance with one exemplary embodiment,

[0027] FIG. 5 shows a vehicle having a circuit assembly or a system in accordance with one exemplary embodiment.

[0028] FIG. 1 shows a typical circuit assembly for connecting and disconnecting a high-voltage battery 101. The circuit assembly has three switches 102, 103, 104. In order to connect the battery, first the switch 104 at the negative terminal and the switch 102 at the positive terminal are closed. The battery 101 can then output current via the resistor 105 to the consumer circuit, wherein precharging of the capacitances of the consumer circuit takes place by virtue of the resistor 105. After the precharging, the precharging branch 102, 105 is bypassed by closing of the switch 103. On disconnection of the battery 101, first the switch 103 is opened. The return current can flow via the resistor 105 and the closed switch 102 to the battery 101. For final disconnection, the switches 102 and 104 are opened.

[0029] FIG. 2 shows a circuit assembly and a system for connecting and disconnecting a high-voltage battery 201 in accordance with one exemplary embodiment of the invention. The circuit assembly has a non-electronic switch, for example, a mechanical switch or a relay 205, and an electronic switch, for example, a transistor 203. In one embodiment, the electronic switch 203 is integrated together with a diode 202 in a component, for example in a SiC MOSFET 204. However, other high-power transistors can also be used, such as, for example, IGBTs or suitable field-effect transistor variants. The integrated diode 202 is, for example, a diode which, owing to its forward direction opposite the forward direction of the transistor, is also referred to as an inverse diode or as a body diode.

[0030] In general, the switch 205 can be closed, but it can be opened for completely disconnecting the battery 201, if necessary. If the battery 201 is connected, a pulsed signal is applied to the gate of the transistor 203, with the result that the capacitances of the consumer circuit are precharged with short current bursts. The effective current intensity can be controlled by the pulse widths until the capacitances are charged. It is therefore possible, for example, to regulate the current intensity at the start by short pulses, and to extend the pulses gradually until there is a steady signal, with the result that, after the precharging phase, the transistor is permanently switched on, i.e. when there is no longer a precharging current flowing or only a low precharging current flows. Alternatively, the current could also be controlled via an analog gate voltage. In this case, a drive circuit for the gate voltage is required, which initially severely limits the battery current during switching-on and then gradually reduces the limitation.

[0031] In order to disconnect the high-voltage battery 201, the transistor 203 is turned off via the gate voltage. The return current can now flow via the integrated diode 202 towards the battery 201. The battery 201 can additionally be mechanically disconnected via the switch 205. This can be used, for example, when it is desirable for there to be no return current flow into the battery.

[0032] The system for switching a high-voltage battery, in one embodiment, has a circuit assembly having at least one precharging circuit 204, a high-voltage battery 201 and a consumer circuit 206 having capacitive properties. The circuit assembly can furthermore have the switch 205.

[0033] FIG. 3 shows a block circuit diagram of a method for connecting a high-voltage battery in accordance with one exemplary embodiment of the invention. The method is performed using the assembly described in FIG. 2. In a first phase 301, during the connection the transistor 203 is switched in pulsed fashion. In this phase, the capacitances of the consumer circuit are precharged. In a second phase 302, during the connection the transistor 203 is switched on. This corresponds to the normal operating mode with the consumer connected, such as, for example, a motor or further circuits such as voltage transformers and further consumers.

[0034] FIG. 4 shows a block circuit diagram of a method for disconnecting a high-voltage battery 201 in accordance with one exemplary embodiment of the invention. The method is performed using the assembly described in FIG. 2. For the disconnection, the transistor 203 is turned off only in 401. The return current can flow via the diode 202 to the battery. Here, the advantage of the assembly is particularly significant since no further switching or no further method steps are required.

[0035] FIG. 5 shows a vehicle 500 in accordance with one embodiment of the invention. The vehicle 500 has a battery 501 and a circuit 502, which corresponds to the circuit assembly shown in FIG. 2, and contains a transistor 203 as described above, having a diode 202. In one embodiment, the circuit assembly furthermore contains a mechanical or electromechanical switch, such as, for example, a relay 205.

[0036] The high-voltage battery 201 can be located at a suitable position in the vehicle, such as, for example, in the vicinity of the front axle or the rear axle. The circuit assembly is preferably located in the vicinity of the battery, with the result that the potential-carrying lines at the terminals of the battery are short. In general, the circuit can also be arranged so as to be physically remote from the battery.