US 11,862,826 B2
Method for determining the compressive tensile force acting on a fuel cell stack
Ian Stewart, Burnaby (CA); Tegan Harrower, Burnaby (CA); and Matej Kusy, Burnaby (CA)
Assigned to Volkswagen AG, Wolfsburg (DE); and Audi AG, Ingolstadt (DE)
Appl. No. 16/644,631
Filed by AUDI AG, Ingolstadt (DE); and VOLKSWAGEN AG, Wolfsburg (DE)
PCT Filed Jun. 20, 2018, PCT No. PCT/EP2018/066354
§ 371(c)(1), (2) Date Aug. 13, 2020,
PCT Pub. No. WO2019/048100, PCT Pub. Date Mar. 14, 2019.
Claims priority of application No. 10 2017 215 510.8 (DE), filed on Sep. 5, 2017.
Prior Publication US 2021/0184234 A1, Jun. 17, 2021
Int. Cl. G01L 5/00 (2006.01); H01M 8/04313 (2016.01); G01L 5/04 (2006.01); H01M 8/248 (2016.01)
CPC H01M 8/04313 (2013.01) [G01L 5/042 (2013.01); H01M 8/248 (2013.01); H01M 2220/20 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method for determining a compressive tensile force acting on a fuel cell stack due to at least one tensioning element, wherein the fuel cell stack has a plurality of fuel cells arranged in a stacking direction between two end plates and at least one tensioning element clamped between the end plates in the stacking direction, the method comprising:
exciting a vibration of a vibratable section of the at least one tensioning element;
detecting an acoustic signal emitted from the vibratable section of the at least one tensioning element;
determining a fundamental frequency of the detected acoustic signal; and
determining a tensile force acting on the vibratable section of the at least one tensioning element on the basis of the determined fundamental frequency, the length of the vibratable section, and the linear mass distribution of the at least one tensioning element.