Systems, apparatus, and methods for battery charge management

Abstract

Systems, apparatus, and methods for automobile battery management is provided. In one embodiment, an apparatus for providing balanced and individualized charging to a battery pack is provided. The apparatus uses microcontrollers to determine a charge level of the batteries, and correspondingly controls a power balancer to apply a charge current to the battery in relation to the charge level, and dissipates the remaining charge current as heat energy. In one embodiment, a system controller controls a balanced charging operation of the battery system, provides an interface for a user to monitor cell-level parameters, and protects the battery cells from undercharging or overcharging during the charging or discharging operations.

I claim the following: 
     
         1 . A method for providing balanced and individualized charging to each battery cell in a plurality of battery cells, the method comprising:
 feeding a total charge current to a first power balancer, wherein the first power balancer regulates an effective charge current applied to a first battery cell of the plurality of battery cells;   controlling the first power balancer using a microcontroller, wherein the microcontroller monitors a current charge level of the first battery cell; and   using the microcontroller to vary a balancing current in the first power balancer such that a difference of the balancing current and the total charge current is applied to as the effective charge current to the first battery cell, wherein the effective charge current is relative to the current charge level of the first battery cell.   
     
     
         2 . The method for providing balanced and individualized charging to each battery cell in the plurality of battery cells as recited in  claim 1 , the method further comprising:
 dissipating as heat energy the balancing current of the first power balancer through a heat sink associated with the first power balancer.   
     
     
         3 . The method for providing balanced and individualized charging to each battery cell in the plurality of battery cells as recited in  claim 1 , wherein the microcontroller is a PID controller. 
     
     
         4 . The method for providing balanced and individualized charging to each battery cell in the plurality of battery cells as recited in  claim 1 , the method further comprising:
 protecting the microcontroller from a failure of the first power balancer using an optical isolator.   
     
     
         5 . The method for providing balanced and individualized charging to each battery cell in the plurality of battery cells as recited in  claim 1 , the method further comprising:
 using the microcontroller to collect and log a plurality of cell parameters.   
     
     
         6 . The method for providing balanced and individualized charging to each battery cell in the plurality of battery cells as recited in  claim 5 , wherein the plurality of cell parameters includes at least one of:
 a voltage level of each of the plurality of battery cells;   a current level of each of the plurality of battery cells;   a temperature level of each of the plurality of battery cells; or   a charge rate of each of the plurality of battery cells.   
     
     
         7 . A system for providing balanced and individualized charging to each battery cell in a plurality of battery cells, the system comprising:
 a first power balancer to receive a total charge current and to regulate an effective charge current applied to a first battery cell of the plurality of battery cells;   a microcontroller to control the first power balancer, wherein the microcontroller monitors a current charge level of the first battery cell; and   wherein the microcontroller varies a balancing current in the first power balancer such that a difference of the balancing current and the total charge current is applied to as the effective charge current to the first battery cell, wherein the effective charge current is relative to the current charge level of the first battery cell.   
     
     
         8 . The system for providing balanced and individualized charging to each battery cell in the plurality of battery cells as recited in  claim 7 , the system further comprising:
 a heat sink associated with the first power balancer to dissipate, as heat energy, the balancing current of the first power balancer.   
     
     
         9 . The system for providing balanced and individualized charging to each battery cell in the plurality of battery cells as recited in  claim 7 , wherein the microcontroller includes a PID controller. 
     
     
         10 . The system for providing balanced and individualized charging to each battery cell in the plurality of battery cells as recited in  claim 7 , the system further comprising:
 an optical isolator to protect the microcontroller from a failure of the first power balancer.   
     
     
         11 . The system for providing balanced and individualized charging to each battery cell in the plurality of battery cells as recited in  claim 7 , wherein the microcontroller collects and logs a plurality of cell parameters. 
     
     
         12 . The system for providing balanced and individualized charging to each battery cell in the plurality of battery cells as recited in  claim 11 , wherein the plurality of cell parameters includes at least one of:
 a voltage level of each of the plurality of battery cells;   a current level of each of the plurality of battery cells;   a temperature level of each of the plurality of battery cells; or   a charge rate of each of the plurality of battery cells.   
     
     
         13 . The system for providing balanced and individualized charging to each battery cell in the plurality of battery cells as recited in  claim 1 , wherein the power balancer includes a power transistor operating in a linear mode. 
     
     
         14 . A system for battery charge management, the system comprising:
 a microcontroller to determine a charge level of each of a plurality of battery cells connected in series and to compute an amount of individual current that needs to be applied to each of the plurality of battery cells to achieve charge balance;   a plurality of power balancers each associated with a subset of the plurality of battery cells, wherein each of the plurality of power balancers is configured to receive an amount of total charging current and deliver an effective charge current corresponding to the amount of total charging current; and   a charge balancer to control, using the microcontroller, the plurality of power balancers by transmitting the amount total charging current indicative of the amount of individual current corresponding to the subset of the plurality of battery cells associated with each of the power balancers.   
     
     
         15 . The system for battery charge management of  claim 14 , wherein the microcontroller monitors voltage and charge rate of each of the plurality of battery cells. 
     
     
         16 . The system for battery charge management of  claim 14 , further comprising a current charger controller to prevent an external charger from supplying current to the charge balancer when any of the plurality of battery cells exceeds parameter levels. 
     
     
         17 . The system for battery charge management of  claim 16 , wherein the current charger controller cycles the effective charge current when a heat dissipation limit associated with the one or more of the plurality of battery cells is exceeded. 
     
     
         18 . The system for battery charge management of  claim 14 , wherein at least two of the plurality of battery cells have different capacities, and wherein to determine a charge level the microcontroller determines a relative state of charge based on a capacity of each of the plurality of battery cells. 
     
     
         19 . The system for battery charge management of  claim 14 , wherein the plurality of battery cells includes Lithium-Ion battery cells, Nickel-Zinc battery cells, Nickel Metal Hydride battery cells, or Lead-acid battery cells. 
     
     
         20 . The system for battery charge management of  claim 14 , further comprising one or more indicators to display the status of the plurality of battery cells as determined by the microcontroller.