Battery pack active discharge integration

A discharge system includes a battery, an electrical power bus selectively connected to the battery, a module configured to receive electrical energy from the battery via the electrical power bus, and a discharge resistor selectively connected to the electrical power bus. A contactor is operatively disposed between the battery and the electrical power bus. The contactor is configured to selectively connect the electrical power bus to the battery or the discharge resistor. That is, the contactor is configured to connect the electrical power bus to the discharge resistor in a default mode to discharge electrical energy stored in the module, and the contactor is configured to connect the electrical power bus to the battery in at least one vehicle operating mode.

TECHNICAL FIELD

The disclosure relates to actively discharging electrical energy stored in an electronic device in a vehicle.

BACKGROUND

Passenger and commercial vehicles may include various electronic devices that receive electrical energy from a battery. The battery may output direct current (DC) electrical energy that may be converted to another DC potential or to alternating current (AC) electrical energy. This way, the battery may support electronic devices that require a high voltage or a low voltage, as well as devices that operate using DC energy or AC energy, using a high, intermediate, or low voltage power bus connected to various modules, such as an inverter, a DC-DC converter, a charger, and other modules.

SUMMARY

An example discharge system includes a battery, a power bus selectively connected to the battery, at least one module configured to receive electrical energy from the battery via the electrical power bus, a discharge resistor selectively connected to the electrical power bus, and a first contactor operatively disposed between the battery and the electrical power bus. The first contactor is configured to selectively connect the electrical power bus to the battery or the discharge resistor. The first contactor is configured to connect the electrical power bus to the discharge resistor in a default mode to discharge electrical energy stored in the module. Further, the first contactor is configured to connect the electrical power bus to the battery in at least one vehicle operating mode.

DETAILED DESCRIPTION

A discharge system that provides a less complex and more cost-effective way to discharge electrical energy across an electrical power bus and stored in one or more modules is described below. The discharge system may take many different forms and include multiple and/or alternate components and facilities. While an example discharge system is shown in the Figures, the components illustrated in the Figures are not intended to be limiting. Indeed, additional or alternative components and/or implementations may be used.

FIG. 1illustrates a discharge system100that may include one or more of a battery105, an electrical power bus110, a discharge resistor115, at least one contactor120, at least one module125, a pre-charge resistor130, a pre-charge contactor135, and a controller140. The discharge system100may be implemented in any passenger or commercial automobile such as a hybrid electric vehicle including a plug-in hybrid electric vehicle (PHEV) or an extended range electric vehicle (EREV), a gas-powered vehicle, a battery electric vehicle (BEV), or the like. The discharge system may additionally or alternatively be used in other applications besides a vehicle.

The battery105may include any device configured to store electrical energy and provide the electrical energy to one or more electronic devices. In one possible approach, the battery105may be configured to output direct current (DC) electrical energy at a predetermined voltage. Moreover, the battery105may include multiple batteries arranged in series or parallel to provide the electrical energy at the predetermined voltage.

The electrical power bus110is selectively connected to the battery105and may include any device configured to convert, for example, the DC electrical energy provided by the battery105to alternating current (AC) electrical energy or another type of electrical energy. In addition or alternatively, the electrical power bus110may be configured to increase or decrease the voltage output by the battery105. This way, the electrical power bus110may be used to provide electrical energy to high and/or low voltage electronic devices that use AC energy or DC energy. The electrical power bus110may include any number of inverters, chargers, AC-DC converters, DC-DC converters, or any other high, intermediate, or low voltage device. The discharge system100may include any number of electrical power busses110, and each electrical power bus110may provide electrical energy from the battery105to any number of modules125.

The discharge resistor115may include any resistive element configured to dissipate electricity or power across one or more electrical devices, such as the electrical power bus110and/or one or more modules125as discussed below. The discharge resistor115may be formed from an element or compound that resists the flow of electricity, such as a nickel-chrome alloy. The discharge resistor115may further include a resistive film that resists the flow of electricity.

The at least one contactor120may include any device configured to selectively connect two electronic components. For example, one or both of the contactors120may be configured to connect the electrical power bus110to either the battery105or the discharge resistor115at any given time. As illustrated inFIG. 1, the discharge system100includes a first contactor145operatively disposed between the battery105and the electrical power bus110and configured to selectively connect the electrical power bus110to the battery105or the discharge resistor115. The first contactor145may be configured to connect the electrical power bus110to the discharge resistor115in a default mode (e.g., a key-off mode) and connect the electrical power bus110to the battery105in at least one vehicle operating mode. A second contactor150may be operatively disposed between the battery105and the electrical power bus110and configured to selectively connect the electrical power bus110to the battery105or the discharge resistor115. For instance, the second contactor150may be configured to connect the electrical power bus110to the discharge resistor115in the default mode and further connect the electrical power bus110to the battery105in one or more vehicle operating modes. In one possible approach, the first contactor145, the second contactor150, or both, may each include a multiple throw switch, such as a single pole double throw (SPDT) switch.

The module125may include any high, intermediate, or low voltage electronic device configured to carry out one or more functions in the vehicle using electrical energy received from the battery105during, e.g., a module active mode of the vehicle. The module125may include one or more of an accessory power module (APM), an air conditioning control module (ACCM), a charger module configured to charge the battery105, a battery heater, or the like. As illustrated inFIG. 1, the modules125are each electrically coupled to the electrical power bus110. In one possible approach, one or more of the modules125, such as the APM, charger module, etc., may be connected directly to the battery105.

The pre-charge resistor130may include any resistive element operatively disposed between the battery105and the electrical power bus110. For instance, during a pre-charge operating mode, electrical energy from the battery105may be directed through the pre-charge resistor130. The pre-charge resistor130may be configured to limit current flow from the battery105to the electrical power bus110at, for example, the instant when the battery105and electrical power bus110are electrically connected to one another. Thus, current may only be directed through the pre-charge resistor130for a short amount of time such as only during the pre-charge operating mode of the vehicle.

The pre-charge contactor135may include any device configured to selectively connect the battery105to the electrical power bus110during, for instance, the pre-charge operating mode of the vehicle. Accordingly, the pre-charge contactor135may be operatively disposed between the battery105and the electrical power bus110. In one example approach, the pre-charge contactor135may include a single throw switch.

The controller140may include any device configured to actuate the first contactor145, the second contactor150, or both, to selectively connect the electrical power bus110to the battery105or the discharge resistor115. For instance, the controller140may be configured to actuate the first contactor145and the second contactor150to connect the electrical power bus110to the discharge resistor115during a default operating mode of the vehicle. The default operating mode may occur any time the vehicle is turned off. In one possible approach, the controller140or another computing device (not shown) may detect a key-off event (e.g., when the driver of the vehicle turns the key to the “off” position). Upon detection of the key-off event, the controller140may cause the first contactor145and the second contactor150to connect the electrical power bus110to the discharge resistor115.

During other operating modes of the vehicle, such as during a pre-charge mode or a module active mode, the controller140may be configured to control the first and second contactor150in other ways. For example, referring toFIG. 2, during the pre-charge mode, the controller140may be configured to cause the pre-charge contactor135to actuate to connect the electrical power bus110to the battery105while diverting current from the battery105through the pre-charge resistor130. Moreover, during the pre-charge mode, the controller140may actuate the second contactor150to connect the electrical power bus110to the battery105. During the module active mode, as illustrated inFIG. 3, the controller140may actuate the first contactor145and the second contactor150to connect the electrical power bus110to the battery105, while actuating the pre-charge contactor135so that no current is diverted through the pre-charge resistor130.

In one possible approach, the controller140may include a vehicle integration control module (VICM) configured to communicate with other computing devices within the vehicle, such as a hybrid control processor, an engine control module, a transmission control module, and/or a motor control module. The controller140may be packaged with the battery105as part of a battery pack155.

FIG. 4illustrates a schematic diagram of an example single pole double throw switch that may be used to implement the contactor120, such as the first contactor145, the second contactor150, or both. The switch may include leads160, a coil165, and a switching element170. In one possible approach, the controller140may control the operation of the switching element170by providing electrical energy to the leads160of the coil165. As the current passes through the coil165, a magnetic field is generated that may act upon the switching element170, thus causing the switching element170to electrically connect the electrical power bus110to either the battery105or the discharge resistor115. The switching element170may be configured to connect the electrical power bus110to the discharge resistor115when no electrical energy is provided to the leads160of the coil165, such as during a default mode of the vehicle (e.g., following a key-off event). However, when electrical energy is provided to the coil165, the magnetic field may either push or pull the switching element170to a position that electrically connects the electrical power bus110to the battery105.

FIG. 5illustrates an example process500that may be used to control the operation of the circuits illustrated inFIGS. 1-3.

At decision block505, the controller140or another computing device may detect the operating mode of the vehicle. For instance, the controller140or another computing device may detect a key-off event (e.g., the driver turning the key to an “off” position), which may indicate the driver's intention to turn off the vehicle. Doing so may indicate to the controller140that the vehicle is in the default mode. When in the default mode, the process500may continue at block510. If a pre-charge is commanded (e.g., to enable one or more of the modules125), the controller140may determine that the vehicle is in the pre-charge mode, at least with respect to the module125about to be enabled. When the controller140determines that the vehicle is operating in the pre-charge mode, the process500may continue at block515. If a module125is enabled and receiving electrical energy, the controller140may determine that the vehicle is operating in the module active mode at least with respect to the enabled module125. In one possible implementation, the module active mode may occur automatically after a predetermined amount of time has elapsed since the beginning of the pre-charge mode. During the module active mode, the process500may continue at block520.

At block510, the controller140may actuate the first contactor145and the second contactor150to electrically connect the electrical power bus110to the discharge resistor115. In one possible implementation, the first contactor145and the second contactor150are configured to default to a position that electrically connects the electrical power bus110to the discharge resistor115. When in the default mode, such as when the vehicle is off, the discharge resistor115may dissipate any electrical energy across the electrical power bus110and/or one or more of the modules125. The process500may continue at block505.

At block515, the controller140may actuate the second contactor150to electrically connect the electrical power bus110to the battery105and actuate the pre-charge contactor135to divert electrical energy from the battery105to the electrical power bus110through the pre-charge resistor130. Doing so my prevent the electrical power bus110and one or more of the modules125from receiving an excess amount of current at the instant the electrical power bus110and/or modules125receives electrical energy from the battery105. After block515, the process500may continue with block505or with block520.

At block520, the controller140may actuate the first contactor145and the second contactor150to electrically connect the electrical power bus110to the battery105. This way, the battery105may provide electrical energy to the electrical power bus110and/or one or more of the modules125. After block520, the process500may continue at block505.