Detection of Low Voltage Electrolysis in a Battery Pack
An apparatus and method providing for detecting and responding to low voltage electrolysis within an electric vehicle battery detecting and responding to low voltage electrolysis within an electric vehicle battery enclosure to limit a possible hazard condition of battery enclosure. The present invention includes embodiments directed towards detection algorithms and apparatus for promoting the use of sensors (e.g., hydrogen, voltage, current, and immersion sensors) for the purpose of detecting low voltage electrolysis. Additionally, the present invention includes response processes and structures to address low voltage electrolysis.
1 . A detection system for low voltage electrolysis in a battery pack, comprising:
an enclosure including a plurality of electrically-coupled battery modules storing energy for the battery pack;
a sensor system, coupled to said enclosure, configured to collect a plurality of data from said enclosure; and
a controller, coupled to said sensor system, configured to evaluate said plurality of data against one or more predetermined patterns associated with a possible low voltage electrolysis of fluid inside said enclosure that generates a flammable gas, with said controller configured to indicate said possible low voltage electrolysis occurring within said enclosure when said plurality of data has a predetermined relationship to said one or more predetermined patterns.
2 . The detection system of claim 1 wherein said enclosure further includes a coolant distribution system disposed among and electrically isolated from said plurality of battery modules; and wherein said coolant distribution system uses a coolant solution that releases hydrogen gas when electrolyzed using a voltage potential of about 5 volts or more.
3 . The detection system of claim 1 wherein said sensor system includes a hydrogen gas sensor and wherein said one or more patterns includes a non-zero concentration of hydrogen gas within said enclosure.
4 . The detection system of claim 1 wherein each said battery module includes a plurality of series-connected energy storage elements with each element having a voltage drop and wherein said sensor system includes a plurality of voltage sensors coupled to said plurality of elements and wherein said one or more patterns includes an anomalous voltage drop for a set of one or more of said elements indicating an internal short-circuit.
5 . The detection system of claim 4 wherein said set of one or more elements include physically adjacent elements from different battery modules.
6 . The detection system of claim 1 wherein each said battery module includes a plurality of series-connected energy storage elements and wherein said sensor system includes a plurality of current sensors for one or more of said elements and a current sensor for terminals of the battery pack and wherein said one or more patterns includes a current sensor reading for one or more of said elements than for a current sensor reading for said battery pack.
7 . The detection system of claim 1 wherein said sensor system includes an immersion sensor measuring an accumulation of a fluid within said enclosure and wherein said one or more patterns includes detection of a non-zero value from said immersion sensor.
8 . The detection system of claim 1 wherein said sensor system includes a first coolant flow rate sensor for an in-flow rate of coolant into said enclosure and a second coolant flow rate sensor for an out-flow rate of coolant out of said enclosure and wherein said one or more patterns includes said in-flow rate exceeding said out-flow rate.
9 . A method for detecting a low voltage electrolysis in a battery pack, the method comprising the steps of:
a) collecting a plurality of data from a sensor system measuring data from an enclosure, said enclosure including a plurality of electrically-coupled battery modules storing energy for the battery pack;
b) evaluating, using a controller, said plurality of data against one or more predetermined patterns associated with a possible low voltage electrolysis of fluid inside said enclosure that generates a flammable gas, with said controller indicating said possible low voltage electrolysis occurring within said enclosure when said plurality of data has a predetermined relationship to said one or more predetermined patterns.
10 . The detecting method of claim 9 wherein said enclosure further includes a coolant distribution system disposed among and electrically isolated from said plurality of battery modules and wherein said coolant distribution system uses a coolant solution that releases hydrogen gas when electrolyzed using a voltage potential of about 5 volts or more.
11 . The detecting method of claim 9 wherein said sensor system includes a hydrogen gas sensor and wherein said one or more patterns includes a non-zero concentration of hydrogen gas within said enclosure.
12 . The detecting method of claim 9 wherein each said battery module includes a plurality of series-connected energy storage elements with each element having a voltage drop and wherein said sensor system includes a plurality of voltage sensors coupled to said plurality of elements and wherein said one or more patterns includes an anomalous voltage drop for a set of one or more of said elements indicating an internal short-circuit.
13 . The detecting method of claim 12 wherein said set of one or more elements include physically adjacent elements from different battery modules.
14 . The detecting method of claim 9 wherein each said battery module includes a plurality of series-connected energy storage elements and wherein said sensor system includes a plurality of current sensors for one or more of said elements and a current sensor for terminals of the battery pack and wherein said one or more patterns includes a current sensor reading for one or more of said elements than for a current sensor reading for said battery pack.
15 . The detecting method of claim 9 wherein said sensor system includes an immersion sensor measuring an accumulation of a fluid within said enclosure and wherein said one or more patterns includes detection of a non-zero value from said immersion sensor.
16 . The detecting method of claim 10 wherein said sensor system includes a first coolant flow rate sensor for an in-flow rate of said coolant solution into said enclosure and a second coolant flow rate sensor for an out-flow rate of said coolant solution out of said enclosure and wherein said one or more patterns includes said in-flow rate exceeding said out-flow rate.