RESISTANCE MEASUREMENT FOR BATTERY CELLS

• US 20130241568A1
• Filed: 02/15/2013
• Published: 09/19/2013
• Est. Priority Date: 02/15/2012
• Status: Active Grant

• Current Assignee: Flextronics International Limited
• Original Assignee: Flextronics International Limited
• Inventors: Covasala, Alexander
• Granted Patent: US 9,140,760 B2
• Time in Patent Office: Days
• US Class Current: 324/439
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/385 Arrangements for measuring battery or accumulator variables for monitoring G01R31/382
• CPC Class Codes: G01R 31/386 using test-loads
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: G01R 31/64 Testing of capacitors

Abstract

A power supply is disclosed that is configured for installation in a motor vehicle. The power supply comprises an energy source and a system for accurately measuring the internal resistance of the energy source during the operation of the power supply, without a distortion that would normally result from discharge of the energy storage device.

Claims

1. A resistance measuring device for the load-independent measurement of the internal resistance (Ri) of an energy storage device, in particular in an electrical system of a motor vehicle, comprises:

an energy storage device coupled in parallel to a component and a switch that is configured to generate a current pulse by switchably coupling a current measuring resistor to the component; and

a measuring device configured to measure a voltage drop (Δ

U) of the energy storage device and to measure a current difference (Δ

i) across the current measuring resistor.

2. The resistance measuring device of claim 1, wherein the component comprises a passive energy storage element, in particular as a capacitor.

3. The resistance measuring device of claim 2, wherein the capacitor comprises an electrolytic capacitor.

4. The resistance measuring device of claim 1, wherein the length of the current pulse generated coupling the current measuring resistor to the component is determined from the total resistance of a circuit comprising the energy storage device, the component, the switch, and the current measuring resistor, and the capacitance of the component.

5. The resistance measuring device of claim 1, wherein the switch comprises a MOSFET.

6. The resistance measuring device of claim 1, wherein the measuring device further comprises a microprocessor configured to determine the internal resistance (Ri) of the energy storage device.

7. The resistance measuring device of claim 1, wherein the switch is positioned between the component and the energy storage device.

8. The resistance measuring device of claim 1, wherein the measurement of Ri is carried out independently of a load coupled to the energy storage device.

9. The resistance measuring device of claim 1, wherein a circuit comprising the component, the switch, the current measuring resistor, and the measuring device is separate from the power path of the energy storage device and a load connected to the energy storage device.

10. The resistance measuring device of claim 1, further comprising a discharge resistor coupled in parallel with the component.

11. A power supply coupled to an electrical system of a motor vehicle, the power supply comprising:

an energy storage device coupled in parallel to a capacitor, the capacitor coupled in parallel with a discharge resistor, and a switch that is configured to generate a current pulse by switchably coupling a current measuring resistor to the capacitor and to the discharge resistor;

and a measuring device configured to measure a voltage drop (Δ

U) of the energy storage device and to measure a current difference (Δ

i) across the current measuring resistor.

12. A power supply according to claim 11, wherein the energy storage device comprises at least one supercap capacitor.