Patent Publication Number: US-2023139052-A1

Title: Coordination chemistry flow battery electrolyte ground fault detection

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to a battery system and method, and more particularly, to detecting a fault within the battery system. 
     BACKGROUND 
     An electrochemical cell of a flow battery includes a cathode side and anode side separated by a separator arrangement. The cathode side can include a cathode current collector, a cathode electroactive material and an electrolyte. The anode side can include an anode current collector, an anode electroactive material and an electrolyte. The separator arrangement separating the cathode and anode sides, permits ionic flow therebetween. The current collectors, electroactive materials, electrolytes and separator arrangement thus form an electrochemical reactor that converts chemical energy to electricity. The current collectors can be electrically connected together to form an electrical circuit. 
     Detecting ground faults in a flow battery system and pinpointing their location is critical in reflow systems. A ground fault is an early indication of a possible leak in the system. The potential difference between the electrolyte and ground is significantly high. A pin hole leak, for example, provides a current conducting path to ground. This path has the potential to carry large amounts of current that can cause excess heat and damage to components of the battery system (e.g., tank liners, pumps, and pipes). If the leak is not detected, it can increase into a larger and larger hole, causing significant damage to the system and loss of electrolyte. 
     The information included in this Background section of the specification, including any references cited herein and any description or discussion thereof, is included for technical reference purposes only and is not to be regarded subject matter by which the scope of the invention is to be bound. 
     SUMMARY 
     The foregoing needs are met, to a great extent, by the battery system described herein. The battery system includes a fault detection system capable of 1.) determining the presence of a fault in the battery system, and 2.) the location of the fault in the battery system. 
     An aspect of the present disclosure provides a battery system. The battery system comprises a battery cell, a detection system, and a controller. The battery cell includes a positive enclosure configured to retain a positive electrolyte and a negative enclosure configured to retain a negative electrolyte. The detection system is electrically coupled between at least one of 1.) the positive electrolyte and a ground, and 2.) the negative electrolyte and the ground. The detection system is configured to detect a parameter of at least one of the positive electrolyte and the negative electrolyte. The controller is configured to receive the parameter from the detection system, compare the parameter to a reference parameter, and determine whether a leak exists in one of the positive and negative enclosures based on the comparison of the parameter to the reference parameter. 
     Another aspect of the present disclosure provides a method for detecting a leak in a flow battery system. The flow battery system includes a battery cell having an enclosure that defines a flow channel configured to receive an electrolyte within. The method comprises: detecting a parameter of the electrolyte within the enclosure; comparing the detected parameter to a reference parameter; and determining whether the leak exists in the enclosure based on the comparison of the parameter to the reference parameter. 
     Another aspect of the present disclosure provides a flow battery system. The flow battery system comprises a battery cell, a detection system, and a controller. The battery cell includes an enclosure that defines a flow channel configured to receive an electrolyte within. The detection system is electrically coupled between the electrolyte and a ground. The detection system comprises a first sensor and a second sensor. The first sensor is electrically coupled to the electrolyte at a first location within the enclosure. The first sensor is configured to sense a first parameter of the electrolyte at the first location. The second sensor is electrically coupled to the electrolyte at a second location within the enclosure. The second sensor is configured to sense a second parameter of the electrolyte at the second location. 
     The controller is configured to receive the first parameter and the second parameter from the detection system, compare the first parameter to a first reference parameter, compare the second parameter to a second reference parameter, determine whether a first leak exists at the first location based on the comparison of the first parameter to the first reference parameter, and determine whether a second leak exists at the second location based on the comparison of the second parameter to the second reference parameter. 
     This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. A more extensive presentation of features, details, utilities, and advantages of the present invention is provided in the following written description of various aspects of the invention, illustrated in the accompanying drawings, and defined in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates a schematic view of a flow battery system, according to an aspect of this disclosure. 
         FIG.  2    illustrates a schematic of a flow battery stack of the flow battery system shown in  FIG.  1   , according to an aspect of this disclosure. 
         FIG.  3    illustrates a schematic view of a detection system, according to an aspect of this disclosure. 
         FIG.  4    illustrates a side view of a portion of a test battery system, according to an aspect of this disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Certain terminology used in this description is for convenience only and is not limiting. The words “top”, “bottom”, “leading”, “trailing”, “above”, “below”, “axial”, “transverse”, “circumferential,” and “radial” designate directions in the drawings to which reference is made. The term “substantially” is intended to mean considerable in extent or largely but not necessarily wholly that which is specified. All ranges disclosed herein are inclusive of the recited endpoint and independently combinable (for example, the range of “from 2 grams to 10 grams” is inclusive of the endpoints, 2 grams and 10 grams, and all the intermediate values). The terminology includes the above-listed words, derivatives thereof and words of similar import. 
     A flow battery system described herein includes an isolated detection system for measuring an electrolyte voltage as referenced to ground at specific locations in the battery system. The locations can include points with higher risk of leaks in the electrolyte fluidic system such as pumps, pipe flanges, valves, or still other locations. The measured voltage can be compared to an expected (or calculated) voltage based on a full battery string voltage. If the measured voltage differs from the expected voltage by a predetermined amount (e.g., 10%), a path to ground exists. The method of measuring the electrolyte voltage using an isolated means can also identify the location (or narrow down the location) where a fault in the battery system has occurred. The detection system can be implemented at multiple locations on the battery system, as described further below. The flow battery system can reduce the time for trouble shooting, down time, and repair costs. 
       FIG.  1    illustrates a schematic of a flow battery system  100 . With the flow battery system  100 , electrodes (e.g., terminal plates) at ends of each of the battery stacks connect electrolytes in supply manifolds with the voltage of the end cells. The flow battery system  100  includes four stacks  102 ,  104 ,  106 , and  108  that are electrically connected to one another by electrical connections  111 . It will be appreciated that the flow battery system  100  can include fewer than or more than four battery stacks. In an aspect, each of the battery stacks  110  can be arranged in series by electrical connections  111 . 
     The flow battery system  100  further includes a negative electrolyte conduit  113 , a positive electrolyte conduit  115 , an anode tank  150 , an anode pump  153 , a cathode tank  152 , and a cathode pump  151 . The anode pump  153  is configured to pump a negative electrolyte  124  from the anode tank  150  through the negative electrolyte conduit  113  and through the battery stacks  110 . Similarly, the cathode pump  151  is configured to pump a positive electrolyte  128  from the cathode tank  152  through the positive electrolyte conduit  115  and through the battery stacks  110 . In an aspect, the electrolyte conduits  113  and  115  for each of the battery stack  110  can be arranged in parallel. 
       FIG.  2    illustrates a schematic of a flow battery stack  110  of the flow battery system  100 , according to an aspect of this disclosure. The flow battery system  100  can include a plurality of flow battery stacks  110 . Each battery stack  110  can include a plurality of independent battery cells  112 . In an aspect, each plurality of battery cells  112  in one battery stack  110  is configured substantially similarly to each of the plurality of battery cells  112  in each of the other battery stacks  110 . 
     The aspects illustrated in  FIGS.  1  and  2    show four battery stack  110  and four battery cells  112 . It will be appreciated that that the flow battery system  100  can include fewer or more battery stack  110  and battery flow cells  112 . The battery flow cells  112  are a type of rechargeable cell in which electrolyte containing one or more dissolved electroactive species flows through (into and out of) an electrochemical reactor that converts chemical energy to electricity. Additional electrolyte containing one or more dissolved electroactive species is stored externally, generally in tanks  150  and  152 , and is usually pumped through the electrochemical reactor (or electrochemical reactors) by pumps  151  and  153  and/or pumps  114  and  116  within each battery stack  110 . The flow cells  112  can have variable capacity depending on the size of the external storage tanks. 
     With reference to  FIG.  2   , each flow cell  112  can include an anode side  116  and a cathode side  118  separated by a separator  120  (e.g., an ion exchange membrane). The anode side  116  includes a negative flow channel  122  configured to receive the negative electrolyte  124 . The cathode side  118  includes a positive flow channel  126  configured to receive the positive electrolyte  128 . The separator  120  permits ionic flow between electroactive materials in the negative flow channel  122  and the positive flow channel  126 . 
     The flow battery stack  110  further includes electrodes  130 . The electrodes  130  can include a first electrode  130   a , a second electrode  130   b , and at least one bipolar electrode  130   c . The electrodes  130  can serve as current collectors. The first electrode  130   a  is connected to the anode side  116  of a first cell  112   a  of the flow cells  112 . The second electrode  130   b  is connected to the cathode side  118  of a second cell  112   b  of the flow cells  112 . Each bipolar electrode  130   c  can be connected between adjacent flow cells  112  of the battery stack  110 . In an alternative, each cell  112  can include a negative electrode and a positive electrode, whereby the negative electrode and the positive electrode of adjacent cells  112  are separated by a bipolar plate (not shown). 
     The negative and positive flow channels  122 ,  126 , the first and second electrodes  130   a ,  130   b , the at least one bipolar electrode  130   c , and the separator  120  form electrochemical reactor that converts chemical energy to electricity (and, in certain arrangements, electricity to chemical energy). The first electrode  130   a  and the second electrode  130   b  can be electrically connected together by a load  132  to form an electrical circuit. 
     The flow battery stack  110  further includes a negative manifold  134  and a positive manifold  136 . The negative manifold  134  includes a negative enclosure that is configured to provide the negative electrolyte  124  to the negative flow channel  122  of each cell  112 . Similarly, the positive manifold  136  includes a positive enclosure that is configured to provide the positive electrolyte  128  to the positive flow channel  126  of each cell. The negative manifold  134  can be connected to the negative flow channel  122  of each battery cell  112  in parallel. In this configuration, the negative electrolyte  124  can be supplied to each negative flow channel  122  from a supply negative manifold portion  138 , and the negative electrolyte  124  flows through each negative flow channel  122  to a receive negative manifold portion  140 . The negative electrolyte  124  can be pumped through the negative manifold  134  and each negative flow channel  122  by the pump  114 . It will be appreciated that the anode tank  150  can contain the negative electrolyte  124 . 
     Similarly, the positive manifold  136  can be connected to the positive flow channel  126  of each battery cell  112  in parallel. In this configuration, the positive electrolyte  128  can be supplied to each positive flow channel  126  from a supply positive manifold portion 142, and the positive electrolyte  128  can flow through each positive flow channel  126  to receive positive manifold portion  144 . The positive electrolyte  128  can be pumped through the positive manifold  136  and each positive flow channel  126  by the pump  116 . It will be appreciated that the cathode tank  152  can contain the positive electrolyte  128 . 
     In an aspect, the manifolds  134 ,  136  can include flow directing structures to cause proper mixing of the electrolytes as they enter each respective flow channel  122 ,  126 . Such flow directing structures may be configured to optimize the flow in each cell  112  within the flow battery stack  110  based upon the expected state of charge and other fluid properties within each cell  112 . 
     The flow battery system  100  further includes a detection system  150 . The detection system  150  is configured to sense or detect a parameter of either or both of the negative and positive electrolytes  124  and  128  as referenced to a ground G. The parameter can include, for example, an electrolyte voltage, an electrolyte current, or other electrolyte parameter. The detection system  150  includes a first at least one sensor  160 , a second at least one sensor  162 , and a controller  170 . The detection system  150  can further include other components commonly used in voltage and/or current detection system, such as, for example, probes, additional sensors, disconnect switches, transceivers, or still other components. 
     As illustrated, the first at least one sensor  160  includes a first sensor  160   a  and a second sensor  160   b . Similarly, the second at least one sensor  162  includes a third sensor  162   a  and a fourth sensor  162   b . It will be appreciated that the detection system  150  can include fewer or more sensors than the four sensors shown. The sensors  160   a  and  160   b  are coupled to the negative manifold  134  to electrically couple the negative electrolyte  124  to the ground G. In an aspect, the sensors  160   a  and  160   b  are connected to the ground G via the controller  170 . Similarly, sensors  162   a  and  162   b  are coupled to the positive manifold  138  to electrically couple the positive electrolyte  128  to the ground G. In an aspect, the sensors  162   a  and  162   b  are connected to the ground G via the controller  170 . The at least one first sensor  160  can provide a signal to the controller  170  indicative of a direct measurement of the parameter of the negative electrolyte  124 . Similarly, the at least one second sensor  162  can provide a signal to the controller  170  indicative of a direct measurement of the parameter of the positive electrolyte  128 . 
     The controller  170  is configured to record data received from the first and second at least one sensors  160  and  162  and determine whether a fault exits in the flow battery system  100  based on at least the data received from the sensors  160  and  162 . The controller  170  can be an electronic control unit, system computer, central processing unit, or other data storage manipulation device that may be used to facilitate control and coordination of any of the methods or procedures described herein. While the controller  170  is represented as two units in  FIG.  2   , in other aspects the controller  170  may be a single unit or distributed as a plurality of distinct but interoperating units, incorporated into another component, or located at different locations on or off the flow battery system  100 . 
       FIG.  3    illustrates a schematic view of the detection system  150 , according to an aspect of this disclosure. For illustrative purposes, only a portion of the battery stack  110  is shown (e.g., the negative manifold  134 ). The controller  170  includes a measurement and isolation barrier  172  and a battery management system  174  (BMS). The barrier  172  is coupled between the first sensor  160  and the BMS  174 , and the barrier  172  is also coupled between the first sensor  160  and the ground G. It will be appreciated that the detection system  150  can include more than one barrier  172 . For example, each at least one sensor  160  and  162  can be electrically coupled to the BMS  174  via a respective barrier  172 . The barrier  172  is configured to receive the signal from the sensor  160  and transmit a detected signal (M2) indicative of the detected parameter of the electrolyte to the BMS  174 . 
     The BMS  174  is configured to receive and store in a memory the detected signal (M2) from the barrier  172  and an expected signal (M1) received from an external source 176. The expected signal (M1) can include, for example, a modeled parameter (e.g., a modeled voltage or a modeled current) of the electrolyte. The modeled parameter can be determined based on a model of the flow battery system  100 . The model of the flow battery system  100  can include, for example, an un-faulted flow battery system, a simulation of a flow battery system, combinations thereof, or still other models capable of determining an expected parameter of the electrolyte. In an aspect, the modeled parameter is an expected modeled voltage as is referenced to a full battery string voltage at a most positive battery stack of the system  100 . 
     The BMS  174  can include a processor, such as a microprocessor, and a memory. The processor may be coupled to and configured to receive signals from the barrier  172  and the external source  176 . Examples of processors include computing devices and/or dedicated hardware as defined herein, but are not limited to, one or more central processing units and microprocessors. In an aspect, the BMS  174  can include an optional communications module to send and receive signals from various locations, either on or remote from the flow battery system  100 . 
     The BMS  174  is configured to compare the detected parameter received from the barrier  172  with the expected parameter from the external source  176 . If the detected parameter differs from the expected parameter by a predetermined value, a fault F in the flow battery system  100  can exist. The predetermined value can be stored in the memory of the BMS  174 . The predetermined value can be modified or adjusted based on, for example, a particular location of the sensors  160  and  162 . The predetermined value can include a percentage difference between the detected parameter and the expected parameter. For example, if the predetermined value is 10%, then the BMS  174  can indicate whether the potential fault F exists when the detected parameter differs from the expected parameter by 10%. If the potential fault F does exist, the BMS  174  can trigger an alarm, either visual, audible, or both, to indicate that the fault F exists in the battery system  100 . 
     When the potential fault F is determined by the BMS  174 , a location of the potential fault F can be identified. For example, if the detected parameter that was detected by the first sensor  160   a  is different from the expected parameter by the predetermined value, then the fault F in the battery system  100  is proximate to the location of the first sensor  160   a . Similarly, if the detected that was detected by the second sensor  160   b  is different from the expected parameter by the predetermined value, then the fault F in the battery system  100  is proximate to the location of the second sensor  160   b . It will be appreciated that the expected parameter at the location of the first sensor  160   a  can be different than the expected parameter at the location of the second sensor  160   b.    
     Multiple first and second sensors  160  and  162  can be deployed throughout the battery system  100  to detect parameters of the negative and positive electrolytes  124  and  128 . In an aspect the first and second sensors  160  and  162  can be positioned proximate to higher risk of fault locations on the battery system  100 . Higher risk fault locations can include, for example, pumps, pipe flanges, valves, or other high resistance locations in the electrolyte loop. 
     The flow battery system  100  can be operated by controlling the pumps  114  and  116  to cause a negative electrolyte and a positive electrolyte to flow from tanks  150  and  152  through the negative and positive manifolds  134  and  136 , respectively. As the electrolytes flow through the respective negative and positive flow channels  122  and  126  of each battery cell  112 , an ion exchange occurs through each separator  120 , and an electrical circuit is formed between each of the battery cells  112  and the load  132 . 
     While the electrolytes are flowing through the negative and positive flow channels  122  and  126  of each battery cell  112 , the first at least one sensor  160  is detecting the parameter of the negative electrolyte  124  flowing through the negative flow channel  122 , and the second at least one sensor  162  is detecting the parameter of the positive electrolyte  128  flowing through the positive flow channel  126 . The detected parameters are sent to the controller  170 . The controller  170  compares the detected parameter with the expected parameter (e.g., reference parameter). If the difference between the detected parameter differs from the expected parameter by a predetermined value, the controller  170  determines that a fault exists in one of or both of the positive and negative enclosures  134  and  136 . 
       FIG.  4    illustrates a side view of a portion of a test battery system  200 , according to an aspect of this disclosure. The battery system  200  includes a pump  202  configured to pump electrolyte through the battery system  100 . The pump  202  can comprise the pump  114 , the pump  116 , or other pump configured to pump electrolyte. An insulating barrier  204  is positioned between the pump  202  and a ground G′. The insulating barrier  204  “floats” the pump  202 , thereby removing the path to ground G′. A grounding conductor  206  is placed between the pump  202  and the ground G′. The grounding conductor  206  includes a circuit breaker  208  configured to selectively ground the pump  202 . A sensor  210  is electrically coupled between an electrolyte within an enclosure  212  of the battery system  200  and the ground G′. 
     Table 1 below represents sample results from a test scenario of the battery system  200 . The data in the first row represents an electrolyte voltage and current when the pump  202  is operational and the circuit breaker  208  is open. The data in the second row represents an electrolyte voltage and current when the pump is operational and the circuit breaker  208  is closed and a fault exists proximate the sensor  210 . 
     
       
         
           
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Circuit Breaker 
                 Electrolyte Voltage 
                 Ground Current 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Open (e.g., pump floating) 
                 247 V 
                 34-66 
                 mA 
               
               
                 Closed (e.g., grounded) 
                  41 V 
                 1.62 
                 A 
               
               
                   
               
            
           
         
       
     
     As represented by the sample results, electrolyte voltage at the area of the ground fault/leak is greatly impacted by the presence of a fault. Once the circuit breaker  208  is closed, the pump  202  is grounded, which puts the fault in the circuit. When the fault is in the circuit, the electrolyte voltage drops from approximately 250V to 40V. This change in voltage of around 200V allows the detection system  150  to determine whether a fault exists in the battery system  200  and the approximate location of the fault (e.g., proximate the sensor  210 ). 
     The flow battery system  100  can provide operational and statistical data that can be utilized in development of advanced algorithms to determine the health of the system ground isolation and better understanding of fluidic voltage in the system  100 . Electrolyte voltage can also be monitored during a shutdown and voltage data decay versus time can be utilized as another data point of possible battery system  100  issues. 
     The detection system  150  can be implemented in multiple areas of the battery system  100 , which can offer better sensitivity to faults and provide greater protection than conventional detection systems. The detection system  150  can aid in the narrowing down and accuracy of determining the location of a fault in the battery system  100 , which can reduce downtime and the time to troubleshoot. This can be particularly important when the detection system  150  is implemented on a large battery system  100 , for example, a reflow energy storage system, whereby determining the location of a fault can be time consuming and costly. The detection system  150  can also provide an early detection of faults before the battery system  100  suffers increasing damage. 
     It will be apparent to those of ordinary skill in the art that variations and alternative embodiments may be made given the foregoing description. Such variations and alternative embodiments are accordingly considered within the scope of the present invention. 
     Joinder references (e.g., attached, coupled, connected, joined, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other. 
     The above specification, examples and data provide a complete description of the structure and use of exemplary aspects of the disclosed technology. Although various aspects of the disclosed technology have been described above with a certain degree of particularity, or with reference to one or more individual aspects, those skilled in the art could make numerous alterations to the disclosed aspects without departing from the spirit or scope of this disclosed technology. Other aspects are therefore contemplated. It is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative only of particular aspects and not limiting. Changes in detail or structure may be made without departing from the basic elements of the disclosed technology as defined in the following claims. 
     Aspects 
     The following Aspects are illustrative only and do not serve to limit the scope of the present disclosure or the appended claims. 
     Aspect 1. A flow battery system, comprising: 
     a battery cell including a positive enclosure configured to retain a positive electrolyte and a negative enclosure configured to retain a negative electrolyte; 
     a detection system electrically coupled between at least one of 1.) the positive electrolyte and the ground, and 2.) the negative electrolyte and the ground, the detection system being configured to detect a parameter of at least one of the positive electrolyte and the negative electrolyte; and 
     a controller configured to receive the parameter from the detection system, compare the parameter to a reference parameter, and determine whether a leak exists in one of the positive and negative enclosures based on the comparison of the parameter to the reference parameter. 
     Aspect 2. The battery system of Aspect 1, wherein the battery system comprises a flow battery system 
     Aspect 3. The battery system of Aspect 1, wherein the battery cell is a first cell of a plurality of cells, wherein each of the plurality of cells includes a respective positive enclosure configured to receive the positive electrolyte and a respective negative enclosure configured to receive the negative electrolyte. 
     Aspect 4. The battery system of Aspect 3, wherein the plurality of cells are arranged in series from the first cell of the plurality of cells to a second cell of the plurality of cells. 
     Aspect 5. The battery system of Aspect 3, wherein the plurality of cells is a first plurality of cells, the battery system further comprising: 
     a first battery stack, wherein the first battery stack comprises the first plurality of cells; and 
     a second battery stack comprising a second plurality of cells, wherein the second plurality of cells is configured substantially similarly as the first plurality of cells. 
     Aspect 6. The battery system of Aspect 1, wherein the parameter comprises a voltage. 
     Aspect 7. The battery system of Aspect 6, wherein the reference parameter is an expected voltage predetermined based on a model of the battery system. 
     Aspect 8. The battery system of Aspect 1, wherein the detection system comprises at least one sensor configured to detect the parameter. 
     Aspect 9. The battery system of Aspect 8, wherein the at least one sensor comprises a plurality of sensors, wherein a first of the plurality of sensors is electrically coupled to at least one of the positive and negative electrolytes at a first location, and wherein a second of the plurality of sensors is electrically coupled to at least one of the positive and negative electrolytes at a second location, wherein the second location is a different location than the first location. 
     Aspect 10. The battery system of Aspect 9, further comprising: 
     a positive electrolyte pump configured to pump the positive electrolyte through the positive enclosure; and 
     a negative electrolyte pump configured to pump the negative electrolyte through the negative enclosure, 
     wherein at least one of the plurality of sensors is positioned at an outlet of at least one of the positive and negative electrolyte pumps. 
     Aspect 11. A method for detecting a leak in a flow battery system, the flow battery system including a battery cell having an enclosure that defines a flow channel configured to receive an electrolyte within, the method comprising: 
     detecting a parameter of the electrolyte within the enclosure; 
     comparing the detected parameter to a reference parameter; and 
     determining whether the leak exists in the enclosure based on the comparison of the parameter to the reference parameter. 
     Aspect 12. The method of Aspect 11, wherein the parameter is a first parameter and the reference parameter is a first reference parameter, and wherein the first parameter is detected at a first location within the enclosure, the method further comprising: 
     detecting a second parameter of the electrolyte at a second location within the enclosure; 
     comparing the second detected parameter to a second reference parameter; and 
     determining whether a leak exists in the enclosure based on the comparison of the second parameter to the second reference parameter. 
     Aspect 13. The method of Aspect 12, wherein the first parameter comprises a first voltage of the electrolyte at the first location, and wherein the second parameter comprises a second voltage of the electrolyte at the second location. 
     Aspect 14. The method of Aspect 11, further comprising: 
     calculating the reference parameter based on a model of the flow battery system. 
     Aspect 15. The method of Aspect 14, wherein the reference parameter is an expected voltage that is predetermined before the determining step. 
     Aspect 16. The method of Aspect 11, wherein the flow battery system further includes an electrolyte pump, wherein the electrolyte pump defines at least a portion of the enclosure, and wherein the parameter of the electrolyte is detected at an outlet of the electrolyte pump. 
     Aspect 17. The method of Aspect 11, wherein the step of detecting the parameter is performed by a sensor electrically coupled between the electrolyte within the enclosure and a ground, the method further comprising: 
     determining a location of the leak in the enclosure based on a location of the sensor. 
     Aspect 18. A flow battery system comprising: 
     a battery cell including an enclosure that defines a flow channel configured to receive an electrolyte within; 
     a detection system electrically coupled between the electrolyte and a ground, the detection system comprising: 
     a first sensor electrically coupled to the electrolyte at a first location within the enclosure, the first sensor being configured to sense a first parameter of the electrolyte at the first location, and 
     a second sensor electrically coupled to the electrolyte at a second location within the enclosure, the second sensor being configured to sense a second parameter of the electrolyte at the second location; and 
     a controller configured to receive the first parameter and the second parameter from the detection system, compare the first parameter to a first reference parameter, compare the second parameter to a second reference parameter, determine whether a first leak exists at the first location based on the comparison of the first parameter to the first reference parameter, and determine whether a second leak exists at the second location based on the comparison of the second parameter to the second reference parameter.