Patent Application
20140253306
Not Applicable.
Not Applicable.
The present invention relates in general to rechargeable electric transportation vehicles, and, more specifically, to a visual indicator of the charge state of a battery during recharging.
Electrically-powered vehicles for roadway use are becoming popular because of reduced energy costs and reduced emissions of pollutants. A full electric or battery electric vehicle (BEV) can be plugged into the high-voltage electric power grid for charging the batteries which then supply all the power for driving the vehicle. A hybrid electric vehicle (HEV) combines the battery and electric drivetrain of a BEV with an internal combustion engine. The gasoline-powered engine may be used to recharge the battery or to provide motive power to the drivetrain, depending on the type of HEV. In a plug-in hybrid (PHEV), the batteries may also be recharged by connecting to the electric grid.
Recharging may typically occur at a power outlet in the car owner's garage or at another recharge location having an appropriate power supply. Since recharging normally requires a significant amount of time, the user leaves the vehicle unattended during most of the recharging process. During charging, it is desirable to display the battery state of charge in order to communicate the recharging progress to the user. This allows the user to anticipate when charging will be complete or to estimate the travel range that has thus far been restored to the battery.
Conventional electrical vehicles typically have used an added indicator placed on or in the vehicle to display the state of charge. Besides the cost of the added components, prior art displays have also required the user to approach or enter the vehicle and to move into the proper position in order to read it.
In one aspect of the invention, an electric vehicle has front, rear, and left and right sides defining four corners and an electric propulsion system including a battery, a charger, and a state of charge monitor determining a battery state of charge. A plurality of exterior lamp assemblies are each disposed at a respective one of the corners. Each lamp assembly is comprised of a sequential chain of LEDs disposed across a respective dimension of the respective lamp assembly. The LEDs of the chain have a placement and separation configured to make the LEDs resolvable at a predetermined distance from the vehicle. The LEDs are configured to be illuminated in a driving mode and a charging mode, wherein the charging mode is comprised of illuminating a portion of the sequential chain of LEDs in proportion to the monitored state of charge of the battery.
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A typical exterior lamp assembly includes elements for generating, collecting, and distributing light as known in the art. Optical elements can include reflectors, light guides, and lenses such as a Fresnel lens. A common light source is an array of light emitting diodes (LEDs), especially for brake signaling, running light, and side or corner marking purposes. To reduce the overall cost of components, the present invention employs dual-purpose LEDs in the lamp assemblies that operate in 1) a driving mode to perform a traditional exterior lighting function (e.g. running lights), and 2) a charging mode to display a state of charge of the battery that is visible from a predetermined distance from the vehicle and from any direction to the vehicle.
The individual LEDs in each sequential chain have a placement, separation, and individual brightness or intensity to make them resolvable at a predetermined distance from the vehicle, such as 100 feet or more. Besides a steady illumination, activation as used herein may also include a flashing/blinking of the LEDs representing the proportion of the battery already charged or the percentage remaining to be charged. The LEDs can also be used to indicate other aspects of the charging status including errors or faults in either the supplied voltage from the outlet or any of the system components. For example, if the vehicle detects a physical (“plugged-in”) connection with the grid outlet but receives no AC power, then the LEDs could be rapidly flashed to indicate the power failure. Thus, various combinations of flashing or sequencing are used to display both fault and non-fault conditions of a charge event.
Lighting control module 64 controls activation of various lighting elements such as interior and exterior lamp assemblies as known in the art. A multiplex bus 65 may be provided to link lighting control module 64 to the controlled lighting elements. Signals from battery controller 63 including the battery state of charge signal are used by lighting control module 64 to determine whether it is in a driving mode or a charging mode.
Lighting control module 64 is connected to a driver 66 corresponding to one of the exterior lamp assemblies containing a plurality of LEDs 67-70 of a sequential chain of LEDs serving a dual purpose of providing substantially uniform illumination to mark a respective corner (e.g., braking or marker lights) in a driving mode and indicating a battery state of charge in a charging mode. LED drivers 71, 75, and 76 selectably provide driving signals to respective LEDs (e.g., LEDs 72-74) in sequential chains located in the exterior lamp assemblies at other corners of the vehicle. Drivers 66, 71, 75, and 76 may preferably be located within the respective exterior lamp assemblies. The drivers may be connected to lighting control module 64 via dedicated connections or via a serial bus to receive control signals identifying the battery state of charge and/or the proportion of LEDs in the sequential chain which should be illuminated according to the monitored battery state of charge during the charging mode.
In operation, the electric vehicle system enters a charging mode upon being connected to the grid power outlet. During charging, a battery state of charge is determined by the battery monitoring controller which may preferably be converted to one of a plurality of predetermined percentage levels of charge, such as in 10% increments. In response to the battery state of charge, a portion of each of the sequential chain of LEDs in the exterior lamp assemblies is illuminated in proportion to the monitored battery state of charge. Since the LEDs and the sequential chain have a placement and separation configured to make them resolvable at a predetermined distance from the vehicle, a user can remotely determine the battery state of charge without approaching the vehicle, entering the vehicle, or performing any special actions to access the display.
When the vehicle is not connected with the grid power outlet, the lighting system enters a driving mode in which the sequential chain of LEDs is activated to provide substantially uniform illumination to mark a respective corner for drivers of other vehicles. In other words, the LEDs serve the dual purpose of acting as part of a brake light, running light, or marker light.
