Battery protection system

Abstract: A battery protection system for the battery (12) of a motor vehicle comprising a switch (16) connectable between the battery and an electrical load (18); a reversible electric motor (14) for opening and closing the switch and connected to the switch on the battery side thereof; a switch opening circuit (22) connected to the switch on the electrical load side thereof; a switch closing circuit (24) connected to the electric motor and to the switch on the battery side thereof; and control means (20) connected to the switch opening circuit and to the switch closing circuit and monitoring predetermined vehicle conditions, the control means actuating the electric motor by way of the switch opening circuit to open the switch, or by way of the switch closing circuit to close the switch, dependent on the monitored vehicle conditions.

Description: Technical Field The present invention relates to a battery protection system for the battery of a motor vehicle. Background of the Invention US patent application no. US 5.200.877 discloses a protection system for a motor vehicle battery according to the preamble of claim 1 in which a reversible electric motor is used to connect and disconnect selected loads under certain vehicle conditions. Summary of the Invention The object of the present invention is to provide an electrical circuit for operating the electric motor. A battery protection system in accordance with the present invention for the battery of a motor vehicle comprises a switch connectable between the battery and an electrical load; a reversible electric motor for opening and closing the switch and connected to the switch on the battery side thereof; a switch opening circuit connected to the switch on the electrical load side thereof; a switch closing circuit connected to the electric motor and to the switch on the battery side thereof; and control means connected to the switch opening circuit and to the switch closing circuit and monitoring predetermined vehicle conditions, the control means actuating the electric motor by way of the switch opening circuit to open the switch, or by way of the switch closing circuit to close the switch, dependent on the monitored vehicle conditions. The present invention a battery protection system which can operate to open the switch if an adverse condition is detected, and/or to close the switch when an adverse condition is not detected. Brief Description of the Drawings The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:- Figure 1 is a circuit diagram of a battery protection system in accordance with the present invention; and Figure 2 is a circuit diagram of a second embodiment of battery protection system in accordance with the present invention. Description of the Preferred Embodiment Referring to Figure 1 of the drawing, the battery protection system 10 is for use with the battery 12 of a motor vehicle in which a reversible electric motor 14 is used to open and close a switch 16 connected between the battery and selected electrical loads 18 in the motor vehicle. The system 10 includes a control unit 20 (preferably including a microprocessor) which monitors predetermined vehicle conditions (such as a collision) and actuates the motor 14 to open or close the switch 16 as required. The system 10 also includes a switch opening circuit 22 and a switch closing circuit 24. The switch opening circuit 22 is connected between the control unit 20 and the side of the switch 16 remote from the battery 12. The switch opening circuit 22 includes a relay 26 which is connected between the switch 16 and the collector of a transistor 28. The base of the transistor 28 is connected to the control unit 20 by way of a resistor 30. The emitter of the transistor 28 is connected to electrical ground. A resistor 32 is connected between the base and the emitter of the transistor 28. A diode 34 is connected between the emitter and the collector of the transistor 28. A capacitor 36 is preferably connected in parallel with the relay 26 to provide power to the electric motor 14 for a limited period of time after the switch 16 opens to ensure complete and full opening of the switch. The switch closing circuit 24 is connected between the control unit 20 and the side of the switch 16 adjacent the battery 12. The switch closing circuit 24 includes a relay 38 which is connected between the switch 16 and the collector of a transistor 40. The base of the transistor 40 is connected to the control unit 20 by way of a resistor 42. The emitter of the transistor 40 is connected to electrical ground. A resistor 44 is connected between the base and the emitter of the transistor 40. A diode 46 is connected between the emitter and the collector of the transistor 40. A diode 48 is preferably connected between the relay 38 and the switch 16. The motor 14 is connected to a motor control relay 50 which is also connected to the side of the switch 16 adjacent the battery 12. The control relay 50 acts to change the polarity of the motor 14 and to actuate the motor. The diode 48 ensures that the motor 14 opens, or keeps open, the switch 16 if a reverse battery condition is detected (for example, during a jump-start where a second battery is incorrectly connected to the battery 12). The switch opening circuit 22 and the switch closing circuit 24 actuate the control relay 50. A manually operable switch 52 may be connected between the control unit 20 and the side of the switch 16 adjacent the battery 12, in parallel with the switch closing circuit 24. The manually operable switch 52 can be used to drive the motor 14 to close the switch 16. The same or a similar manually operable switch may be provided for manually driving the motor 14 to open the switch 16. In the second embodiment of a battery protection system 100 as shown in Figure 2, like parts (when compared to the embodiment of Figure 1) have been given the same reference numeral. In comparison to Figure 1, the capacitor 36 has been removed and the connection from the relay 26 to the switch 16 is replaced by a circuit 60 which provides power to the electric motor 14 for a limited period of time after the switch 16 opens. The circuit 60 is also connected between the diode 48 of the switch closing circuit 24 and the switch 16 to provide power to the electric motor 14 for a limited period of time after the switch 16 closes. The circuit 60 comprises a pair of resistors 62, 64 and a diode 66 connected in series as shown between the switch 16 and electrical ground. The base of a first transistor 68 is connected between the resistors 62,64, and the emitter of the first transistor is connected to the switch 16. The collector of the transistor 68 is connected to the relay 26, the collector of a second transistor 70, and a capacitor 72. The base of the second transistor 70 is connected between a pair of resistors 74,76 which are connected in series, and in series with the capacitor 72, between the collector of the first transistor 68 and the diode 48 and the control relay 50. The emitter of the second transistor 70 is also connected to the diode 48 and the control relay 50. A diode 78 is connected between the emitter and the collector of the second transistor 70. The present invention operates to open the switch 16 if an adverse condition is detected, and/or to close the switch when an adverse condition is not detected, by the control unit. The present invention may also include arrangements for ensuring full and complete opening of the switch, and for opening the switch if a reverse battery condition is detected.

Claims: A battery protection system (10) for the battery (12) of a motor vehicle comprising a switch (16) connectable between the battery and an electrical load (18); a reversible electric motor (14) for opening and closing the switch and connected to the switch on the battery side thereof; a switch opening circuit (22); a switch closing circuit (24) connected to the electric motor and to the switch on the battery side thereof; and control means (20) connected to the switch opening circuit and to the switch closing circuit and monitoring predetermined vehicle conditions, the control means actuating the electric motor by way of the switch opening circuit to open the switch, or by way of the switch closing circuit to close the switch, dependent on the monitored vehicle conditions; characterised in that the switch opening circuit is connected to the switch on the electrical load side thereof. A battery protection system as claimed in Claim 1, wherein the switch opening circuit includes circuit means (36,60) for providing power to the electric motor for a limited period of time after the switch opens. A battery protection system as claimed in Claim 2, wherein the circuit means includes a capacitor (36). A battery protection system as claimed in Claim 2, wherein the circuit means (60) includes a first transistor (68) having a base connected between a pair of resistors (62,64) connected in series between the switch (16) and electrical ground, the emitter of the first transistor being connected to the switch. A battery protection system as claimed in Claim 4, wherein the circuit means further includes a second transistor (70) having a base connected between a pair of resistors (74,76) connected in series between the collector of the first transistor (68) and the switch closing circuit (24), a collector connected to the collector of the first transistor, and an emitter connected to the switch closing circuit. A battery protection system as claimed in any one of Claims 1 to 5, wherein the switch closing circuit (24) includes a diode (48) for preventing closing of the switch (16) by the electric motor (14) if power of incorrect polarity is connected to the battery (12). A battery protection system as claimed in any one of Claims 1 to 6, wherein a control relay (50) is connected across the electric motor (14), the control relay acting to alter the polarity of the electric motor and to actuate the electric motor, the switch opening circuit (22) and the switch closing circuit (24) actuating the control relay. A battery protection system as claimed in any one of Claims 1 to 7, wherein a manually operable switch (52) is connected in parallel with the switch closing circuit (24).

Inventors: KULLICK PETER, VOLPONE MATTEW, KULLICK, PETER, VOLPONE, MATTEW
Applicants: DELPHI TECH INC, DELPHI TECHNOLOGIES, INC.
Application year: 2000
Main classification: B60R16
IPC codes: H01H3