Balancing voltage for a multi-cell battery system

US8598847B2 · kind B2 · utility

Assignees

• VOLKSWAGEN AKTIENGESELLSCHAFT · DE
• AUDI AG · DE

Inventors

• Martin Eberhard · Woodside, US
• Steve Diamond · Scottsdale, US
• Marc Tarpenning · Palo Alto, US
• Jessica Riley · Mountain View, US
• Alexander Barke · Ingolstadt, DE
• Manfred Ammler · Bergheim, DE
• Reinhard Hofmann · Wien, AT

Key dates

• Filing date: Jan 19, 2011
• Grant date: Dec 3, 2013
• Expiry date: Aug 3, 2032

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/70
• WIPO field: Transport
• WIPO sector: Mechanical engineering

Abstract

A method for balancing voltage for a multi-cell battery system, in which the battery system includes at least two parallel groups of cells connected in series and in which the parallel group of cells includes at least one battery cell, includes: charging the battery system by keeping the voltage of all parallel groups of cells less than or equal to a second threshold voltage value, while at least the voltage of one group of parallel cells is less than or equal to a first threshold voltage; and while at least the voltage of one group of parallel cells is less than or equal to a second threshold voltage; and while the charging current is above a predefined minimal current. The method further includes measuring the voltage of each parallel group of cells while electrical loads are shut off and dissipating energy in each of the parallel group of cells of the amount that is represented by the voltage difference between the individual parallel group of cells and the parallel group of cells with the lowest voltage.