METHOD FOR MONITORING CURRENT SENSORS

• US 20170168131A1
• Filed: 04/09/2015
• Published: 06/15/2017
• Est. Priority Date: 05/08/2014
• Status: Abandoned Application

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schneider, Joerg, Follath, Florian
• Application Number:
  US15/309,058
• Publication Number:
  US 20170168131A1
• Time in Patent Office: Days
• CPC Class Codes: B60L 3/0038 relating to sensors
• CPC Class Codes: G01R 19/0092 measuring current only all subgroups of G01R19/00 take precedence
• CPC Class Codes: G01R 19/10 Measuring sum, difference or ratio
• CPC Class Codes: G01R 31/36 Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
• CPC Class Codes: G01R 35/00 Testing or calibrating of apparatus covered by the other groups of this subclass
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

This invention relates to a method for monitoring current sensors (7), (8), (9) during the determining of a total electric current, I, from a battery, preferably from a lithium-ion battery, in an electrical circuit (1) having current sensors (7), (8) in a parallel conductor section (3) with at least two parallel conduction paths (5), (6), for determining the respective current components I₁, I₂. According to the invention, the electric circuit (1) has a further current sensor (9) for determining the total current I. In a scaling step, scaling factors S₁, S₂ are defined, by the use of which current components I₁, I₂ flowing in the parallel conduction paths (5), (6) can be scaled up to the total current, I. In a monitoring step, measured current components I_M1, I_M2 are scaled up by means of scaling factors S₁, S₂ and thus calculated total currents I_B1 (10), I_B2 (11) are defined and compared with one another and with a total current I_M (12) determined by the current sensor (9). The invention further relates to a battery system with a control device configured to perform such a method.

Claims

1. A method for monitoring current sensors (7), (8), (9) when determining a total electric current I from a battery in an electrical circuit (1), said electrical circuit (1) having a total conductor section (2) and a parallel conductor section (3) connected in series with the total conductor section (2), wherein the total conductor section (2) has a total conductor line (4) and the parallel conductor section (3) has at least two parallel conduction paths (5), (6), the total current I flowing in the total conductor line (4) and respectively one current component I₁, I₂ flowing in each of the at least two parallel conduction paths (5), (6), wherein the at least two conduction paths (5), (6) have in each case a current sensor (7), (8) for determining the respective current components I₁, I₂, characterized in that the electrical circuit (1) has a current sensor (9) for determining the total current I in the total conductor line (4), and

a) in a scaling step

defining an associated scaling factor S₁, S₂ in each case for the conduction paths (5), (6), said scaling factor describing an inverse relationship of the respective current component I₁, I₂ in the respective conduction path (5), (6) to the total current I in the total conductor line (4), and

b) in a monitoring step

b1) measuring current components I_M1, I_M2 by current sensors (7), (8) in the respective conduction paths (5), (6)

b2) determining a measured total current I_M (12) by the current sensor (9) in the total conductor line (4),

b3) calculating a total current I_B1 (10), I_B2 (11) of the respective links of the measured current components I_M1, I_M2 using the associated scaling factors S₁, S₂, and

b4) comparing the calculated total currents I_B1 (10), 1_B2 (11) with one another as well as in each case with the measured total current I_M (12) in order to monitor the current sensors (7), (8), (9).

2. The method according to claim 1, characterized in that the calculated total currents I_B1 (10), I_B2 (11) are compared with one another as well as with the measured total current I_M (12) by the amount of a difference (13), (14), (15) being determined between the calculated total currents I_B1 (10), I_B2 (11) with one another and between the respective calculated total currents I_B1 (10), I_B2 (11) and the measured total current I_M (12);

and in that respectively two of the compared currents I_B1 (10), I_B2 (11), I_M (12) are considered to be equally high if the respective difference (13), (14), (15) lies below a predeterminable maximum value.

3. The method according to claim 2, characterized in that the parallel conductor section (3) has exactly two parallel conduction paths (5), (6) and the monitoring takes place in such a way that no or a positive control message is emitted if the two calculated total currents I_B1 (10), I_B2 (11) and the measured total current I_M (12) are considered to be equally high, and/or that a warning message is emitted -if one of the compared currents I_B1 (10), I_B2 (11), I_M (12) deviates from at least one further compared current I_B1 (10), I_B2 (11), I_M (12), and/or that the total current I in the total conductor line (4) is interrupted by an interruption device and/or an error message is emitted if all of the compared currents I_B1 (10), I_B2 (11), I_M (12) are not considered to be equally high.

4. The method according to claim 1, characterized in that the scaling factors S₁, S₂ are defined via measurements such that a scaling current flows in the total conductor line (4) of the total conductor section (2), said scaling current being divided in the parallel conductor section (3) into at least two scaling current components in the at least two conduction paths (5), (6) that are connected in parallel, and the measurements take place by the current sensors (7), (8), (9).

5. The method according to claim 4, characterized in that the amount of the scaling current in the total conductor line (4) is at least 50 amperes.

6. The method according to claim 4, characterized in that a scaling error is defined in the scaling step, said scaling error being determined as the amount of a difference between the scaling current measured in the total conductor line (4) and the sum of scaling current components measured in the at least two conduction paths (5), (6) that are connected in parallel, and wherein the scaling factors S₁, S₂ are only calculated as long as the scaling error lies below an adjustable scaling tolerance.

7. The method according to claim 1, characterized in that the scaling step takes place during start-up of the electrical circuit (1).

8. The method according to claim 1, characterized in that the current sensors (7), (8) each comprise a shunt.

9. The method according to claim 1, characterized in that the current sensor (9) comprises a Hall sensor.

10. A battery system comprising a battery and an electrical circuit (1) connected to the battery, the electrical circuit (1) including a total conductor section (2) and a parallel conductor section (3) connected in series with the total conductor section (2), and the total conductor section (2) has a total conductor line (4) and the parallel conductor section (3) has at least two parallel conduction paths (5), (6), said at least two parallel conduction paths (5), (6) each having a current sensor (7), (8) for determining current components I₁. I₂, characterized in that the battery system has a current sensor (9) in the total conductor line (4) for determining a total current I that is delivered by the battery and wherein a control device is furthermore provided, which is equipped to carry out a method according to claim 1.

11. The method according to claim 2, characterized in that the parallel conductor section (3) has exactly two parallel conduction paths (5), (6) and the monitoring takes place in such a way that no or a positive control message is emitted if the two calculated total currents I_B1 (10), I_B2 (11) and the measured total current I_M (12) are considered to be equally high.

12. The method according to claim 2, characterized in that the parallel conductor section (3) has exactly two parallel conduction paths (5), (6) and the monitoring takes place in such a way that a warning message is emitted if one of the compared currents I_B1 (10), I_B2 (11), I_M (12) deviates from at least one further compared current I_B1 (10), I_B2 (11), I_M (12).

13. The method according to claim 2, characterized in that the parallel conductor section (3) has exactly two parallel conduction paths (5), (6) and the monitoring takes place in such a way that the total current I in the total conductor line (4) is interrupted by an interruption device if all of the compared currents I_B1 (10), I_B2 (11), I_M (12) are not considered to be equally high.

14. The method according to claim 2, characterized in that the parallel conductor section (3) has exactly two parallel conduction paths (5), (6) and the monitoring takes place in such a way that an error message is emitted if all of the compared currents I_B1 (10), I_B2 (11), I_M (12) are not considered to be equally high.

15. The method according to claim 6, wherein the adjustable scaling tolerance is one ampere.

16. The battery system according to claim 10, wherein the battery is a lithium-ion battery.