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System and method for rebalancing a battery during vehicle operationSystem and method for rebalancing a battery during vehicle operation description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070080664, System and method for rebalancing a battery during vehicle operation. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This invention relates to a system and method for rebalancing a battery during vehicle operation. [0003] 2. Background Art [0004] Conventional electric (EV), hybrid electric (HEV), and fuel cell (FC) vehicles generally include one or more batteries. Each battery is generally composed of a plurality of electrochemical cells (i.e., cells) combined in series to produce a potential. The smallest unit (i.e., grouping) of cells for which a state of charge (SOC) may be determined is generally referred to as a module. [0005] The cells and/or modules of the battery are generally matched by capacities and voltages during the battery fabrication process. The fabrication process may also include charging and discharging the battery to confirm that all module voltages are within a specified tolerance at all voltage levels. The assembly process generally provides a battery having module voltages within a few milli-volts of one another. [0006] Over time, ambient conditions and/or charging/discharging the battery during vehicle operation may result in differences among the individual SOC of the cells (SOC.sub.cell). The SOC.sub.cell variations are generally observed as divergence in module voltages (i.e., states of charge) since a module is generally the smallest grouping (i.e., unit) of cells for which a state of charge (SOC) may be determined. [0007] Conventionally, the batteries are controlled between predefined minimum and maximum SOC limits to prevent over-discharge and over-charge of any cell within the battery. When a module approaches the minimum SOC limit, the battery discharge current is driven to zero. When a module approaches the maximum SOC limit, the battery charge current is driven to zero. Thus, any divergence among SOC modules may reduce the operating range of the battery which may, in turn, result in reduced battery performance and a reduced battery life. Accordingly, it is generally desirable to rebalance the battery when a divergence among module SOC is identified. [0008] Conventional methods for rebalancing the battery (i.e., reducing or eliminating module SOC divergence) require low-rate constant-current overcharge of the cells/modules. Such low-rate constant-current overcharge generally requires precise control of charge current (e.g., 1 to 2 Amperes) and may require a long period of time (e.g., 5 hours or more) to complete. [0009] Conventional hybrid and fuel cell vehicle charge-control systems are generally not configured to control the charge current within the conventional rebalancing range during vehicle operation. Furthermore, during recharging of the cells (i.e., battery recharging), the vehicle may experience decreased operating performance (e.g., poor vehicle acceleration, reduced fuel economy, etc.). The decreased vehicle performance may result in a vehicle operator perceiving different or unusual vehicle behavior. [0010] Conventional recharging of a pure electric vehicle generally rebalances the cells of the EV battery. Such rebalancing of EV batteries is generally possible because the vehicle is plugged into a steady power supply (e.g., the United States power grid) and allowed to slowly charge to a full SOC during EV recharging. The slow charging process inherently rebalances the SOC of the cells. However, rapid EV recharge techniques are under development which may reduce the inherent rebalancing of an EV battery during EV recharging. Accordingly, purely electric vehicles may also require a system and method for rebalancing a battery during vehicle operation. [0011] Therefore, a system and method for rebalancing a battery (i.e., the cells of the battery, the modules of the battery, etc.) during vehicle operation may be desirable. Furthermore, a system and method for rebalancing a battery during vehicle operation that reduces and/or eliminates recharge related vehicle performance degradation and/or improves control of the charge current may be desirable. SUMMARY OF THE INVENTION [0012] Accordingly, one or more embodiments of the present invention may provide a system and/or method for rebalancing a battery during vehicle operation that reduces and/or eliminates recharge related vehicle performance degradation and/or improves control of the charge current during battery rebalancing. [0013] In at least one embodiment of the present invention, a method for rebalancing a battery in a vehicle during vehicle operation, the battery including a plurality of modules, is provided. The method may include determining when an automatic rebalance mode start condition is satisfied, modifying a target state of charge for the battery at least in part in response to the start condition being satisfied such that the target state of charge is raised from a standard operating value to a rebalance value, operating the vehicle with the target state of charge at the rebalance value, determining when an automatic rebalance mode end condition or an interrupt condition is satisfied, and modifying the target state of charge in response to the automatic rebalance mode end condition or the interrupt condition being satisfied such that the target state of charge is lowered from the rebalance value to the standard operating value. [0014] In at least one other embodiment of the present invention, a system for rebalancing a battery in a vehicle during vehicle operation is provided. The system may include a battery having a plurality of modules wherein each of the modules includes one or more cells, and a controller in electronic communication with the battery. The controller may determine when an automatic rebalance mode start condition is satisfied, modify a target state of charge for the battery at least in part in response to the start condition being satisfied such that the target state of charge is raised from a standard operating value to a rebalance value, determine when an automatic rebalance mode end condition or an interrupt condition is satisfied, and modify the target state of charge in response to the end condition or the interrupt condition being satisfied such that the target state of charge is lowered from the rebalance value to the standard operating value. BRIEF DESCRIPTION OF THE DRAWINGS [0015] FIG. 1 is a block diagram illustrating a system for rebalancing a battery in a vehicle during vehicle operation according to one embodiment of the present invention; [0016] FIG. 2 is a flow diagram of a method for rebalancing a battery in a vehicle during vehicle operation according to one embodiment of the present invention; and [0017] FIGS. 3 (a-c) are charge efficiency versus SOC curves corresponding to various steps of a method for rebalancing a battery in a vehicle during vehicle operation according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) [0018] Referring to FIG. 1, a block diagram illustrating a system 100 for rebalancing a battery in a vehicle (i.e., electric vehicle, hybrid electric vehicle, fuel cell vehicle, etc.) during vehicle operation according to one embodiment of the present invention is shown. The system may include a controller 102, a battery 104, a cruise control actuator 106, a vehicle speed sensor 108, and/or a diagnostic device 110. [0019] The controller 102 may be electronically coupled to the battery 104, the cruise control actuator 106, the vehicle speed sensor 108 and/or the diagnostic device 110 such that electronic signals may be transmitted between the controller 102 and one or more components (i.e., 104, 106, 108, 110) of the system 100. In general, the controller 102 may include a processor and/or other electronic device (e.g., an Application Specific Integrated Circuit and/or the like) which executes software application programs, executes firmware, and/or which performs other logical exercises. In at least one embodiment of the present invention, the controller 102 may execute the method 200 described in detail in connection with FIG. 2. [0020] It is contemplated that all or part of the functionality of the controller 102 may be incorporated into a single controller as shown in FIG. 1, such as a vehicle system controller (VSC). Alternatively, the functionality of the controller 102 may be distributed among a plurality of controllers (not shown). Controller inputs and outputs (i.e., electronic signals) may be received and passed between controllers via a Controller Area Network (CAN), dedicated communication wires, and the like. Continue reading about System and method for rebalancing a battery during vehicle operation... Full patent description for System and method for rebalancing a battery during vehicle operation Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this System and method for rebalancing a battery during vehicle operation patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like System and method for rebalancing a battery during vehicle operation or other areas of interest. ### Previous Patent Application: Portable charger with a rechargeable back-up battery Next Patent Application: Methods and apparatus for coupling an energy storage system to a variable energy supply system Industry Class: Electricity: battery or capacitor charging or discharging ### FreshPatents.com Support Thank you for viewing the System and method for rebalancing a battery during vehicle operation patent info. IP-related news and info Results in 0.12819 seconds Other interesting Feshpatents.com categories: Accenture , Agouron Pharmaceuticals , Amgen , AT&T , Bausch & Lomb , Callaway Golf 174 |
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