Dynamic pressure control in a battery assembly

Abstract

Operating a battery assembly that includes one or more rechargeable battery cells includes: monitoring one or more operational parameters of the battery cells; and dynamically controlling pressure applied to the one or more battery cells based at least in part on one or more of the monitored operational parameters.

What is claimed is: 
     
         1 . An apparatus comprising:
 a plurality of rechargeable battery cells arranged in a stack;   at least one sensor configured to monitor one or more operational parameters of the plurality of battery cells;   a coolant system for flowing coolant between neighboring battery cells within the plurality of battery cells;   a pressure monitoring system for monitoring a pressure applied to the plurality of battery cells by the coolant flowing between neighboring battery cells among the plurality of battery cells; and   a pressure control system configured to dynamically vary a pressure applied to the plurality of battery cells to yield a monitored pressure having a target value that changes based at least in part on one or more of the monitored operational parameters, wherein the pressure control system is arranged to dynamically vary the pressure of the coolant flowing between neighboring battery cells to dynamically vary the pressure applied to the plurality of battery cells.   
     
     
         2 . The apparatus of  claim 1 , wherein the pressure control system is configured to vary the pressure applied to the plurality of battery cells as a function of one or more of the monitored operational parameters. 
     
     
         3 . The apparatus of  claim 1 , wherein the pressure control system comprises
 a rigid housing with the plurality of battery cells contained with the rigid housing; and   a pressure modulator configured to dynamically vary the pressure of the coolant to dynamically vary the pressure applied to the plurality of battery cells.   
     
     
         4 . The apparatus of  claim 3 , wherein the pressure monitoring system comprises one or more pressure sensors configured to monitor pressure applied to the plurality of battery cells. 
     
     
         5 . The apparatus of  claim 4 , wherein the pressure control system further comprises control circuitry configured to receive input from the one or more pressure sensors and to provide a control signal to the pressure modulator. 
     
     
         6 . The apparatus of  claim 1 , wherein the coolant system comprises a plurality of coolant flow plates interleaved among the plurality of battery cells. 
     
     
         7 . The apparatus of  claim 6 , wherein the pressure control system is configured to dynamically vary the pressure of coolant flowing through the plurality of coolant flow plates to dynamically vary the pressure applied to the battery cells among the plurality of battery cells. 
     
     
         8 . The apparatus of  claim 6 , wherein the pressure control system comprises a pump for flowing coolant through the plurality of coolant flow plates and wherein the pressure control system is configured to change a flow rate of the coolant flowing through the plurality of coolant flow plates to dynamically vary the pressure applied to the plurality of battery cells. 
     
     
         9 . The apparatus of  claim 1 , wherein at least one of the operational parameters is charging rate, state of charge, or temperature of the cells. 
     
     
         10 . The apparatus of  claim 1 , wherein at least one of the operational parameters is charging rate and wherein the pressure control system is configured to dynamically control pressure applied to the plurality of battery cells as a function of the charging rate. 
     
     
         11 . The apparatus of  claim 1 , wherein the pressure monitoring system comprises a sensor for detecting a change in a volume of a coolant region within the battery assembly. 
     
     
         12 . The apparatus of  claim 11 , wherein the volume change sensor comprises a diaphragm or a piston.