Battery monitor for electric vehicles

• US 5,646,534 A
• Filed: 01/06/1995
• Issued: 07/08/1997
• Est. Priority Date: 01/06/1995
• Status: Expired due to Term

• Current Assignee: Chrysler Group LLC (Stellantis NV)
• Original Assignee: Chrysler Corporation (Stellantis NV)
• Inventors: Kopera, John J. C.
• Primary Examiner(s): Wieder, Kenneth A.
• Assistant Examiner(s): BROWN, GLENN WARNER
• Application Number:
  US08/369,250
• Time in Patent Office: 914 Days
• Field of Search: 324/434, 324/431, 324/426, 340/636, 320/48
• US Class Current: 324/434
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A battery monitor for monitoring the voltage and temperature of the batteries associated with a battery pack of an electric vehicle. The battery monitor includes an opto-isolator that electrically separates an isolated portion of the battery monitor connected to the batteries from a non-isolated portion of the battery monitor that transmits battery voltage and temperature signals to a vehicle controller of the electric vehicle. The battery monitor is positioned proximate to a battery tub holding the batteries of the electric vehicle so that high voltage wires connected to the batteries within the battery tub are limited in length for safety purposes. Further, a limited number of wires transmitting the battery voltage and battery temperature signals from the battery monitor to the vehicle controller are required. The battery monitor can include a multiplexer that selectively transmits the battery voltage and temperatures signals to the opto-isolator in a controlled manner, or can include a series of other opto-isolators that transmit high power battery signals to a capacitor to be charged where the charge on the capacitor is representative of the voltage of a particular battery.

Claims

1. A battery monitor for monitoring a plurality of batteries, said battery monitor comprising:

means for providing battery voltage signals indicative of the battery voltage of each of the plurality of batteries;

a single multiplexing device having a predetermined number of channels, said multiplexing device being responsive to the battery voltage signals from the plurality of batteries through the means for providing battery voltage signals, said multiplexing device outputting a selected one of the battery voltage signals;

isolator means for receiving the selected battery voltage signal and transferring the selected battery voltage signal to a portion of the battery monitor isolated from the battery voltage signals from each of the plurality of batteries;

controller means for receiving the selected battery voltage signal, said controller means providing a signal indicative of the voltage of the selected battery voltage signal; and

switching means for allowing the controller means to determine the battery voltage of the selected battery voltage signal when current from the plurality of batteries is flowing in the battery monitor and when current from the plurality of batteries is interrupted, said switching means including at least one switched filter that is selectively switched into and out of the battery monitor by the controller means through the isolator means prior to the battery voltage signals being applied to the multiplexing device, said at least one switched filter allowing the controller means to provide an instantaneous battery voltage measurement when the switched filter is switched out of the battery monitor, and a filtered battery voltage measurement when the switched filter is switched into the battery monitor.

2. The battery monitor according to claim 1 further comprising temperature measuring means for determining the temperature of at least some of the plurality of batteries, said temperature measuring means transmitting a battery temperature signal to the multiplexing device, said multiplexing device selecting a battery temperature signal to be transferred to the controller means.

3. The battery monitor according to claim 2 wherein the temperature measuring means for determining the battery temperature includes a thermistor.

4. The battery monitor according to claim 1 wherein the isolator means is a plurality of opto-isolators, wherein an opto-isolator is provided for each battery being monitored, and wherein a particular opto-isolator charges a capacitor when the particular opto-isolator is selected to determine a particular battery voltage.

5. The battery monitor according to claim 1 wherein the isolator means is an opto-isolator, said opto-isolator isolating the battery voltage of each of the plurality of batteries from the controller means.

6. The battery monitor according to claim 1 wherein the multiplexing device is responsive to the controller means to determine which of the battery voltage signals will be the selected battery voltage signal from the multiplexing device.

7. The battery monitor according to claim 1 wherein the battery monitor monitors the batteries associated with an electric vehicle, said battery monitor being positioned proximate to a battery tub that holds the plurality of batteries.

8. The battery monitor according to claim 1 wherein the means for providing a battery voltage signal includes a resistor divider network.

9. A battery monitor for monitoring a plurality of batteries, said battery monitor comprising:

means for providing battery voltage signals indicative of the battery voltage of each of the plurality of batteries;

selecting means for selecting one of the battery voltage signals from the plurality of batteries;

isolator means for receiving the selected battery voltage signal and transferring the selected battery voltage signal to a portion of the battery monitor isolated from the battery voltage signals from each of the plurality of batteries;

controller means for receiving the selected battery voltage signal from the selecting means through the isolator means, said controller means providing a signal indicative of the voltage of the selected battery voltage signal; and

switching means for allowing the controller means to determine the battery voltage of the selected battery voltage signal when current from the plurality of batteries is flowing in the battery monitor and when current from the plurality of batteries is interrupted, said switching means including at least one switched filter that is selectively switched into and out of the battery monitor by the controller means through the isolator means, said at least one switched filter allowing the controller means to provide an instantaneous battery voltage measurement when the switched filter is switched out of the battery monitor, and a filtered battery voltage measurement when the switched filter is switched into the battery monitor.

10. The battery monitor according to claim 9 wherein the at least one switched filter is a plurality of switched filters where one switched filter is provided for each battery, said switched filters filtering the battery voltage signals before the battery voltage signals are applied to the selecting means.

11. The battery monitor according to claim 9 further comprising temperature measurement means for determining the temperature of at least some of the plurality of batteries, said temperature measurement means transmitting battery temperature signals to the selecting means, said selecting means selecting a battery temperature signal to be transferred to the controller means.

12. The battery monitor according to claim 9 wherein the selecting means is a single multiplexing device having a predetermined number of channels, said multiplexing device being responsive to the battery voltage signals from the plurality of batteries, said multiplexing device outputting a selected one of the battery voltage signals.

13. The battery monitor according to claim 9 wherein the isolator means is an opto-isolator, said opto-isolator isolating the battery voltage of each of the plurality of batteries from the controller means.

14. The battery monitor according to claim 9 wherein the selecting means is responsive to the controller means to determine which of the battery voltage signals will be the selected battery voltage signal from the selecting means.

15. The battery monitor according to claim 9 wherein the battery monitor monitors the batteries associated with an electric vehicle, said battery monitor being positioned proximate to a battery tub that holds the plurality of batteries in the vehicle.

16. A battery monitor for monitoring a plurality of batteries of an electric vehicle, said battery monitor comprising:

means for providing a battery voltage signal indicative of the battery voltage of each of the plurality of batteries;

a single multiplexing device having a predetermined number of channels, said multiplexing device being responsive to the battery voltage signals from the plurality of batteries through the means for providing a battery voltage signal, said multiplexing device outputting a selected one of the battery voltage signals;

temperature measuring means for determining the temperature of at least some of the plurality of batteries, said temperature measuring means transmitting a battery temperature signal to the multiplexing device, said multiplexing device outputting a selected one of the battery temperature signals;

controller means for receiving the selected battery voltage signal and the selected battery temperature signal, said controller means determining the battery voltage of the selected one of the battery voltage signals and the battery temperature of the selected one of the battery temperature signals;

isolator means for separating the battery monitor into a high voltage side and a low voltage side, said plurality of batteries being on the high voltage side and said controller means being on the low voltage side, wherein the selected battery voltage signal and the selected battery temperature signal from the multiplexing device are applied to the controller means through the isolator means and signals from the controller means to the multiplexing device for selecting one of the battery voltage signals and the battery temperature signals are applied through the isolator means; and

switching means for allowing the controller means to determine the battery voltage of the selected voltage signal when current from the plurality of batteries is flowing in the battery monitor and current from the batteries is interrupted, wherein the switching means includes at least one switched filter that is selectively switched into and out of the battery monitor by the controller means through the isolator means, said at least one switched filter allowing the controller means to provide an instantaneous battery voltage measurement when the switched filter is switched out of the battery monitor, and a filtered battery voltage measurement when the switched filter is switched into the battery monitor.

17. The battery monitor according to claim 16 wherein the at least one switched filter is a plurality of switched filters where one switched filter is provided for each battery, said switched filters filtering the battery voltage signals before the battery voltage signals are applied to the multiplexing device.