Patent Application
20130193920
Embodiments disclosed herein generally relate to an apparatus and method of dual use resistor for a battery disconnect.
It is known to provide a resistor that is used in connection with a pre-charging function and battery heating. One example of this is set forth in U.S. Publication No. 2012/0040224 (the “'224 Publication”) to Reischmann et al.
The '224 Publication provides a battery circuit for an electric vehicle that employs a resistor that performs both a pre-charging function at system start-up and battery heating. The battery circuit includes a positive high voltage bus line electrically coupled to a positive terminal of the battery and a negative high voltage bus line electrically coupled to the negative terminal of the battery. A first end of the resistor is electrically coupled to the positive high voltage bus line, a first switch is electrically coupled between a second end of the resistor and the positive high voltage bus line and a second switch is electrically coupled between the second end of the resistor and the negative high voltage bus line. The pre-charging operation is provided when the first switch is closed and the second switch is opened. The heating function is provided when the second switch is closed and the first switch is opened.
A vehicle apparatus comprising a battery charger is provided. The battery charger is operably coupled to a power grid to receive AC energy during a vehicle charging operation and is operably coupled to a switching circuit for one of connecting and disconnecting the battery in the vehicle. The switching circuit includes a single resistor and is arranged to enable a pre-charge operation and a battery heating operation. The battery charger is configured to convert the AC energy into DC energy for delivering at least a portion of the DC energy to the single resistor for performing the battery heating operation when the vehicle charging operation is being performed.
The embodiments of the present disclosure are pointed out with particularity in the appended claims. However, other features of the various embodiments will become more apparent and will be best understood by referring to the following detailed description in conjunction with the accompany drawings in which:
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.
The embodiments of the present disclosure generally provide for a plurality of circuits or other electrical devices. All references to the circuits and other electrical devices and the functionality provided by each, are not intended to be limited to encompassing only what is illustrated and described herein. While particular labels may be assigned to the various circuits or other electrical devices disclosed, such labels are not intended to limit the scope of operation for the circuits and the other electrical devices. Such circuits and other electrical devices may be combined with each other and/or separated in any manner based on the particular type of electrical implementation that is desired. It is recognized that any circuit or other electrical device disclosed herein may include any number of microprocessors, integrated circuits, memory devices (e.g., FLASH, random access memory (RAM), read-only memory (ROM), electrically programmed read-only memory or (EPROM), electrically erasable programmable read-only-memory (EEPROM), or other suitable variants thereof) and software which co-act with one another to perform operation(s) as disclosed herein.
A battery system in, but not limited to, a hybrid or electric plug-in vehicle may utilize, for example, a pre-charge function for a smooth transition to match voltages before activating main contactors. A liquid-cooled battery, for example, may utilize a heating function to achieve operating temperatures in cold weather.
In one implementation as disclosed herein, a battery system may combine pre-charge and heating function via a single resistor (e.g., tapped thick film resistor) that may be adhered to an outer surface of a tube carrying flowing coolant. The single tap resistor may allow for independent resistance values for each function (e.g., pre-charge and heating) to minimize cost.
In one implementation as disclosed herein, a battery system may combine pre-charge and heating functions by using a single untapped resistor that may be adhered to the outer surface of the tube carrying flowing coolant (or some other resistive heating element). The untapped configuration may include that the heating function is not activated during pre-charge. Also, the untapped configuration may provide a single resistance value that is compatible with both the heater function and the pre-charge function. It is recognized that the implementations disclosed herein may provide a single resistor that may reduce cost and/or packaging space. These aspects and more will be described in more detail below.
In general, the switching circuit 16 generally includes a plurality of switching devices, which may in the form of, but not limited to, contactors, relays, field effect transistors (FETs) etc. In general, the switching circuit 16 generally includes contactor 22a, contactor 22b, contactor 24a, contactor 24b (e.g., contactors 24a and 24b may be main contactors), contactor 26 (or pre-charge contactor 26), FET 28, and a battery disconnect contactor 29. While
The resistor 30, upon drawing current, is generally arranged to heat liquid flowing through the tube segment 32 to heat the battery 12. The tube segment 32 is generally arranged to extend about the battery 12, and the resistor 30 for thermally communicating with the same. This will be discussed in more detail in connection with
To account for the degrading effect on the electronics, the controller 14 may activate the pre-charge contactor 26 via signal PRECHG and the contactor 24b via signal MAINNEG prior to activating the main contactor 24a during a vehicle start up condition.
Accordingly, the controller 14 may activate FET 28 via signal HEATER. Path 38 illustrates that power flows from positive side of battery 12, the resistor 30, the FET 28, the battery disconnect contactor 29, a fuse 40 and back to negative side of battery 12. In general, while the resistor 30 receives power, the resistor 30 heats liquid that flows through the tube segment 32. The battery 12 is thermally coupled to the tube segment 32 for receiving the heated coolant. The resistance value of the resistor 30 may be the same for purposes of performing the heating operations (also for that noted in connection with
As noted above, the first mode generally corresponds to a pre-charging operation that is being performed. Accordingly, in the first mode, the controller 14 activates the pre-charge contactor 26 via signal PRECHG and the contactor 24b via signal MAINNEG prior to activating the main contactor 24a during a vehicle start up condition. In response to the pre-charge contactor 26 and the contactor 24b being activated, path 36 illustrates that power flows from the battery 12, the first portion 44 of the resistor 30′, the pre-charge contactor 26, positive side of inverter 20, the capacitor 34, negative side of the inverter 20, the contactor 24b, and back to negative side of battery 12.
The first portion 44 of the resistor 30′, once the pre-charge contactor 26 and the contactor 24b is active, functions to limit current from the battery 12 to the inverter 20 thereby causing the capacitor 34 to charge before the controller 14 activates the main contactor 24a. Such a condition may eliminate the short circuit condition (or large spikes) at the capacitor 34 in the event the main contactors 24a and 24b are activated without first pre-charging the capacitor 34. Once the capacitor 34 is charged, the controller 14 activates the contactor 24a just prior to deactivating the pre-charge contactor 26 while continuing to activate the contactor 24b. This condition will allow the battery 12 to provide the high DC voltage to the inverter 20.
As further noted above, the resistance value of the second portion 46 of the resistor 30′ may be different than the resistance value of the first portion 44. For example, the resistance value of the second portion 46 may be suitable for heating operations while the resistance value of the first portion 44 may be suitable for the pre-charge operation. By providing a single tapped resistor 30′, this condition may minimize cost and packaging space when compared to an implementation that used multiple resistors with each having different resistance values to enable the pre-charge and heating operations.
In this second mode, the second portion 46 the resistor 30′ receives power from the battery 12, which in turn heats liquid that flows through the tube segment 32. The battery 12 is thermally coupled to the tube segment 32 for receiving the heated coolant.
Path 42 illustrates that power flows from the grid 15, positive side of charger 18, the contactor 22a, the second portion 44 of the resistor 30′, the contactor 22b, and back to negative side of charger 18. In this third mode, the second portion 46 the resistor 30′ receives power, which in turn heats liquid that flows through the tube segment 32 for heating the battery 12.
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.
This application claims the benefit of U.S. provisional Application No. 61/590,892 filed on Jan. 26, 2012, the disclosure of which is incorporated in its entirety by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 61590892 | Jan 2012 | US |
