Method and control device for impedance-based determination of a state of charge of at least one battery cell and motor vehicle

US11604227B2 · kind B2 · utility

Assignee

• AUDI AG · DE

Inventors

• Dorothea Kalin · Munich, DE
• Rolf Naumann · Krefeld, DE
• Christian Roettinger · Ingolstadt, DE

Key dates

• Filing date: Oct 7, 2021
• Grant date: Mar 14, 2023
• Expiry date: Oct 7, 2041

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R31/374
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method for determining a state of charge of at least one battery cell, having the following steps to enable an improved determination of the state of charge of a lithium iron phosphate cell: generating an alternating current pulse in a circuit connected to the at least one battery cell, determining an impedance of the at least one battery cell on the basis of the alternating current pulse and determining the state of charge by comparing the impedance to predefined map data, wherein a relationship between the impedance and the state of charge of the at least one battery cell is determined from the predefined map data.