Fluid regulating microvalve assembly for fluid consuming cells

Abstract

A fluid regulating microvalve assembly for use to control fluid flow to a fluid consuming electrode, such as an oxygen reduction electrode, in an electrochemical cell. The microvalve assembly includes a stationary valve body having an aperture and a microactuator movable from a first position where the microvalve body aperture is closed to fluid flow to at least a second position where fluid is able to pass through the microvalve body aperture. The fluid regulating microvalve assembly can utilize cell potential or a separate source to open and close the microvalve. The fluid regulating microvalve assembly can be located outside the cell housing or inside the cell housing, for example between one or more fluid inlet apertures and the fluid consuming electrode. The invention includes a method of making a multilayer microvalve assembly, particularly one for use in a fluid depolarized battery, using a printing process to deposit at least one of the layers.

1 . An electrochemical cell, comprising a housing comprising one or more fluid inlet apertures, a negative electrode, a fluid consuming positive electrode, and a microvalve assembly operatively connected to the one or more fluid inlet apertures for controlling passage of fluid to the fluid consuming positive electrode, wherein the microvalve assembly comprises;
 (a) a stationary microvalve body comprising an aperture located between a first surface and a second surface;   (b) a movable microactuator connected to the microvalve body and capable of moving between a first position where fluid cannot pass through the microvalve body aperture and a second position which allows fluid to pass through the microvalve body aperture; and   (c) a latch, operatively connected to the microvalve body, the latch comprising a moveable latch component that changes shape upon application of a potential across the moveable latch component.   
   
   
       2 . The electrochemical cell according to  claim 1 , wherein the moveable latch component is a multi-layer component that can heat and bend when current passes therethrough. 
   
   
       3 . The electrochemical cell according to  claim 2 , wherein the multi-layer component comprises a first sublayer with a coefficient of thermal expansion and a second sublayer with a coefficient of thermal expansion that is different from the coefficient of thermal expansion of the first sublayer. 
   
   
       4 . The electrochemical cell according to  claim 1 , wherein the moveable latch component has an arm-like shape. 
   
   
       5 . The electrochemical cell according to  claim 4 , wherein the moveable latch component extends from the microvalve body to contact the microactuator to hold the microactuator in the second position without the flow of current through either of the microactuator or the latch. 
   
   
       6 . The electrochemical cell according to  claim 4 , wherein the microvalve assembly is operatively connected to a control unit for controlling the application of a potential to at least one of the microactuator and the latch. 
   
   
       7 . The electrochemical cell according to  claim 6 , wherein a portion of the control unit is disposed on a portion of the microvalve assembly. 
   
   
       8 . The electrochemical cell according to  claim 4 , wherein the moveable latch component comprises a surface having a layer disposed thereon for preventing adhesion of the moveable latch component to other portions of the microvalve assembly. 
   
   
       9 . The electrochemical cell according to  claim 1 , wherein the microvalve assembly further comprises a layer of material between the body and the actuator. 
   
   
       10 . The electrochemical cell according to  claim 9 , wherein the layer of material does not adhere to the actuator. 
   
   
       11 . The electrochemical cell according to  claim 9 , wherein the layer of material does not adhere to the body. 
   
   
       12 . An electrochemical cell, comprising a housing comprising one or more fluid inlet apertures, a negative electrode, a fluid consuming positive electrode, and a microvalve assembly operatively connected to the one or more fluid inlet apertures for controlling passage of fluid to the fluid consuming positive electrode, wherein the microvalve assembly comprises;
 (a) a body comprising an aperture located between a first surface and a second surface;   (b) a movable actuator connected to the body and capable of moving between a closed position where fluid cannot pass through the aperture and an open position which allows fluid to pass through the aperture; and   (c) a latch for holding the actuator in the open position without consumption of power by undergoing a change in shape in response to application of a potential across the moveable latch component.   
   
   
       13 . The electrochemical cell according to  claim 12 , wherein the latch is a multi-layer latch that can bend when the potential is applied. 
   
   
       14 . The electrochemical cell according to  claim 12 , wherein the latch comprises a resistive material that can bend in response to heating when a current flows therethrough. 
   
   
       15 . The electrochemical cell according to  claim 12 , wherein the microvalve assembly is operatively connected to a control unit for controlling the application of a potential to at least one of the actuator and the latch. 
   
   
       16 . The electrochemical cell according to  claim 1 , wherein the applied potential originates within the cell. 
   
   
       17 . The electrochemical cell according to  claim 1 , wherein the cell is an air-depolarized or air-assisted cell. 
   
   
       18 . The electrochemical cell according to  claim 1 , wherein the microvalve assembly is disposed within the cell housing. 
   
   
       19 . The electrochemical cell according to  claim 1 , wherein the microvalve assembly is disposed outside the cell housing. 
   
   
       20 . The electrochemical cell according to  claim 19 , wherein the cell is capable of installation in an appliance in which the microvalve assembly is mounted.