Method for the diagnosis of thermal runaway in an electric battery

7) An electric battery (1) comprising:

• at least one stack (2) of electrochemical cells (3) connected to one another in series;
• a first measuring instrument (6) for each electrochemical cell (3), which is configured to measure a first electric voltage (Vcell-i) at the ends of the electrochemical cell (3);
• a second measuring instrument (7), which is configured to measure a second electric voltage (Vstack) at the ends of the entire stack (2) of electrochemical cells (3);
• and
• a control unit (8), which is configured to diagnose a thermal runaway of an electrochemical cell (3), if the first electric voltage (Vcell-i) is smaller than a first threshold value (TH1);
• wherein the control unit (8) is configured for the steps of:
• calculating a difference between the second electric voltage (Vstack) and the sum of all first electric voltages (Vcell-i);
• and
• diagnosing a thermal runaway of an electrochemical cell (3), only if the difference between the second electric voltage (Vstack) and the sum of all first electric voltages (Vcell-1) is smaller than a second threshold value (TH2);
• measuring all second electric voltages (Vstack) at the ends of each stack of the plurality of stacks (2) of electrochemical cells (3), identical to one another, making up the electric battery (1);
• determining, among all second electric voltages (Vstack) at the ends of each stack of the plurality of stacks (2) of electrochemical cells (3), a maximum second electric voltage (Vstackmax) and a minimum second electric voltage (Vstackmin);
• calculating a difference between the maximum second electric voltage (Vstackmax) and the minimum second electric voltage (Vstackmin);
• and
• diagnosing a thermal runaway of an electrochemical cell (3), only if the difference between the maximum second electric voltage (Vstackmax) and the minimum second electric voltage (Vstackmin) is greater than a third threshold value (TH3).

8) A method for the diagnosis of thermal runaway in an electric battery (1) comprising at least one stack (2) of electrochemical cells (3) connected to one another in series;

• the diagnosis method comprises the steps of:
• measuring a first electric voltage (Vcell-i) at the ends of each electrochemical cell (3);
• measuring a second electric voltage (Vstack) at the ends of the entire stack (2) of electrochemical cells (3);
• diagnosing a thermal runaway of an electrochemical cell (3), if the first electric voltage (Vcell-i) of the electrochemical cell (3) is smaller than a first threshold value (TH1);
• calculating a difference between the second electric voltage (Vstack) and the sum of all first electric voltages (Vcell-i);
• and
• diagnosing a thermal runaway of an electrochemical cell (3), only if the difference between the second electric voltage (Vstack) and the sum of all first electric voltages (Vcell-i) is smaller than a second threshold value (TH2).

9) An electric battery (1) comprising:

• at least one stack (2) of electrochemical cells (3) connected to one another in series;
• a first measuring instrument (6) for each electrochemical cell (3), which is configured to measure a first electric voltage (Vcell-i) at the ends of the electrochemical cell (3);
• a second measuring instrument (7), which is configured to measure a second electric voltage (Vstack) at the ends of the entire stack (2) of electrochemical cells (3);
• and
• a control unit (8), which is configured to diagnose a thermal runaway of an electrochemical cell (3), if the first electric voltage (Vcell-i) is smaller than a first threshold value (TH1);
• wherein the control unit (8) is configured for the steps of:
• calculating a difference between the second electric voltage (Vstack) and the sum of all first electric voltages (Vcell-i);
• and
• diagnosing a thermal runaway of an electrochemical cell (3), only if the difference between the second electric voltage (Vstack) and the sum of all first electric voltages (Vcell-i) is smaller than a second threshold value (TH2).