Method and apparatus for managing energy in plural energy storage units

Abstract

A system for managing energy stored in a plurality of series connected energy storage units has a plurality of energy storage unit controllers, each associated with one of the plurality of energy storage units, a balancing circuit between two of the energy storage units, being controlled by at least one of the energy storage unit controllers, a serial electrical interface between the energy storage unit controllers providing voltage isolated bi-directional communication, and a central controller in electrical communication with the energy storage unit controllers. A method for managing charge in a plurality of series connected energy storage units in which current is diverted from the first energy storage unit to the second energy storage unit.

1 . A system for managing energy stored in a plurality of series connected energy storage units, the system comprising:
 a plurality of energy storage unit controllers, each controller being associated with one of the plurality of energy storage units;   a balancing circuit between two of the energy storage units, the balancing circuit being controlled by at least one of the energy storage unit controllers;   a serial electrical interface between the energy storage unit controllers for providing voltage isolated bi-directional communication; and   a central controller in electrical communication with the energy storage unit controllers.   
     
     
         2 . The system of  claim 1 , wherein the energy storage unit comprises one or more storage cells. 
     
     
         3 . The system of  claim 1 , wherein the energy storage unit controller monitors a parameter of the associated energy storage unit selected from the group consisting of voltage, temperature, and current. 
     
     
         4 . The system of  claim 1 , wherein the balancing circuit includes a reactive element and at least one switch, the switch being controlled by at least one of the energy storage unit controllers. 
     
     
         5 . The system of  claim 1 , wherein a voltage monitored by any one energy storage unit controller is no more than 5 V. 
     
     
         6 . The system of  claim 1 , wherein the communications are digital communications. 
     
     
         7 . The system of  claim 1 , comprising a current sense resistor in series with the energy storage units. 
     
     
         8 . The system of  claim 7 , wherein the central controller monitors a current in the current sense resistor. 
     
     
         9 . The system of  claim 1 , comprising a disconnect switch in series with the energy storage units. 
     
     
         10 . The system of  claim 9 , wherein the disconnect switch is operatively interfaced to the control chip. 
     
     
         11 . The system of  claim 1 , wherein the storage unit controllers can be a separate integrated circuit, a discrete component, or a hybrid of an integrated circuit and a discrete component. 
     
     
         12 . The system of  claim 1 , wherein the integrated circuit can be in a multichip module. 
     
     
         13 . The system of  claim 1 , wherein the serial electrical interface provides bidirectional, two way alternate, using bit asynchronous transfer, byte synchronous logical ring with contra flow. 
     
     
         14 . A system for managing energy stored in plural series connected energy storage units comprising:
 first means for monitoring voltage across a first energy storage unit;   second means for separately monitoring voltage across a second energy storage unit; and   means for balancing charge among the first and second energy storage units by exchanging energy among the first and second energy storage units in response to the first and second monitoring means during at least one of charging and discharging of the first and second energy storage units, the charge balancing means including a reactive equalization circuit.   
     
     
         15 . The system of  claim 14 , wherein the first monitoring means monitors a temperature of the first energy storage unit. 
     
     
         16 . The system of  claim 14 , wherein the second monitoring means monitors a temperature of the second energy storage unit. 
     
     
         17 . The system of  claim 14 , wherein the charge balancing means includes an inductor, at least one switch and a diode connected across each switch. 
     
     
         18 . The system of  claim 14 , comprising means for monitoring current in the plural series connected energy storage units. 
     
     
         19 . The system of  claim 14 , comprising means for voltage isolated bidirectional communications between each means for voltage monitoring. 
     
     
         20 . The system of  claim 19 , wherein the communications are digital communications.