Method and device for reducing incorrect measurements during the determination of electrical parameters of electrical components

Abstract

Before technical components are further processed, they are checked for the functionality thereof. In this case, an incorrect judgment of the functionality can occur due to measurement errors or incorrect measurements, which in turn results in a very inefficient test. The invention provides a method and a device by which an increased measurement accuracy can be achieved. This is achieved in that at least one first electrical voltage value is measured at a first constant measurement current and at least one second electrical voltage value is measured at a second constant measurement current at terminals of the component. Every measured voltage value is scaled respectively using a profile factor PF to form a measured value M, and only measured values M that are located at least with a tolerance range in a common value range are used for the determination of an electrical parameter.

Claims

1. A method for reducing incorrect measurements during the determination of electrical parameters at terminals of an electrical component, the method comprising: measuring at least one first electrical voltage value at a first constant measurement current at the terminals; and measuring at least one second electrical voltage value at a second constant measurement current at the terminals; wherein every measured voltage value is scaled respectively using a profile factor PF to form a measured value M, and wherein only measured values M that are located at least with a tolerance range in a common value range are used for the determination of the electrical parameter.

2. The method according to claim 1, wherein the electrical parameters are an electrical resistance and/or an electrical capacitance.

3. The method according to claim 1, wherein the electrical component is a battery.

4. The method according to claim 1, wherein multiple first electrical voltage values are measured and/or multiple second electrical voltage values are measured.

5. The method according to claim 1, wherein the first voltage value is measured at a first measurement current of 0 A and the second voltage value is measured at a second measurement current not equal to 0 A.

6. The method according to claim 5, wherein the second measurement current is 1 A.

7. The method according to claim 1, wherein the first and the second measurement current are applied in succession over an identical time period at the terminal.

8. The method according to claim 7, wherein the first and the second measurement current are applied in succession over half of a measurement time at the terminal.

9. The method according to claim 1, wherein to determine a profile factor PF of the first measured voltage value, the first measured voltage value is divided by an arithmetic mean value of all first measured voltage values, and to determine a profile factor PF of the second measured voltage value, the second measured voltage value is divided by an arithmetic mean value of all second measured voltage values.

10. The method according to claim 1, wherein to determine the measured value M for every measured first or second voltage value, the voltage value is divided by the respective determined profile factor PF.

11. The method according to claim 1, wherein the tolerance range is determined for every measured value M, wherein to determine an upper value of the tolerance range, the product of the measured value M and a tolerance factor is added to the measured value M and, to determine a lower value of the tolerance range, the product of the measured value and the tolerance factor is subtracted from the measured value M.

12. The method according to claim 11, wherein the tolerance factors are determined by at least one test measurement.

13. The method according to claim 1, wherein the measured values M that are located with the tolerance range thereof in the common value range are used to respectively determine an arithmetic mean value for the first and second measured voltage values, and wherein the electrical parameter is determined from the arithmetic mean values and the first and second measurement current.

14. The method according to claim 13, wherein the electrical parameter is an electrical resistance, a capacitance, an inductance, or an impedance of a resonant circuit.

15. The method according to claim 1, wherein 1 to 500 first and second voltage values are measured for each current value per millisecond.

16. The method according to claim 1, wherein 5 to 100 first and second voltage values are measured for each current value per millisecond.

17. The method according to claim 1, wherein 5 to 20 first and second voltage values are measured for each current value per millisecond.

18. The method according to claim 1, wherein the electrical parameters are determined simultaneously at multiple batteries.

19. The method according to claim 18, wherein the multiple batteries are battery arrangements or battery modules for automobiles.

20. A device for carrying out a method for reducing incorrect measurements during the determination of electrical parameters at terminals of electrical components according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A preferred exemplary embodiment of the present invention is explained in greater detail hereafter on the basis of the drawing. In the figures:

(2) FIG. 1a shows an illustration of a time curve of a measurement current;

(3) FIG. 1b shows an illustration of the first and second voltage measured values over the measuring time;

(4) FIG. 2 shows an illustration of the voltage measured values at various points in time; and

(5) FIG. 3 shows an illustration of a relative location of the measured values in relation to a tolerance range.

DETAILED DESCRIPTION OF THE INVENTION

(6) To be able to determine electrical parameters of an electrical component, for example, a battery, according to the invention, a constant measurement current is firstly applied at the terminals or at the corresponding contacts, respectively, of the component. For this first measurement current, a first voltage value is then measured via the terminals or contacts, respectively (FIG. 1a). The electrical resistance of the electrical component may be determined, for example, from the voltage measured value thus measured and the measurement current. However, the capacitance of the component and also the inductance and/or the impedance or another electrical variable or parameter can thus conceivably be determined at least substantially without measurement error.

(7) To now increase the measurement accuracy of this measurement and thus generate a more reliable result, a second voltage measured value is measured at a second measurement current over the same terminals or contacts, respectively. In the measurement illustrated by way of example in FIG. 1, the ascertainment of the first voltage measured values is carried out at an amperage of 0 A and the measurement of a second voltage measured value is carried out at a second amperage of 1 A. In this case, the measurement currents are applied over an identical time period, namely each over half of the stimulation time, at the terminals.

(8) To now furthermore also minimize the influence of random electrical noise, not only one first voltage measured value and also one second voltage measured value are ascertained, but rather a plurality, preferably n measured values M. The measurement of these n measured values M is carried out, however, in each case in the constant time periods over which the current values are applied at the terminals (FIG. 1b). To now further increase the quality of the measurement results and/or minimize the influences of electromagnetic interference signals on the measurement, every measured first voltage measured value is divided by the arithmetic mean of all first voltage values. A profile factor PF is thus determined for every voltage value. These profile factors PF are determined both for the first and also for the second measured voltage values.

(9) In a further method step, every first and second voltage value is then respectively divided by its own profile factor PF for the determination of a measured value M. These measured values M1 to M5 for the first measured voltage values are illustrated by way of example in FIG. 2. It is apparent that the measured values M1 to M5 thus ascertained, although they were measured under identical conditions, deviate significantly from one another. This deviation results from the systematic and random electrical interference signals.

(10) For the further computation of the electrical parameters, firstly the measured values M are eliminated that do not fall in a tolerance range to be determined. For this purpose, the measured values M1 to M5 illustrated in FIG. 2 are offset using a tolerance factor. Specifically, to establish an upper tolerance value, the product of the respective measured value M1 to M5 and the tolerance factor is added to each measured value M1 to M5. A lower tolerance value for each measured value M1 to M5 is ascertained by subtraction of the product of each measured value M1 to M5 and the tolerance factor from the respective measured value M1 to M5. The upper and lower measured values thus computed are illustrated by arrows in FIG. 3.

(11) For the judgment as to whether the measured values M are suitable for the further computation of the electrical parameters, a tolerance range is established or defined. This tolerance range is illustrated by horizontal dashed lines in FIG. 3. In the example illustrated in FIG. 3, the measured values Ml, M2, M3, and M5 fall at least partially with the measured value range thereof determined by the measured values M in the tolerance range and thus qualify as suitable for the further utilization. The measured value M4 is clearly not in the tolerance range and is therefore not considered for the further computation of the electrical parameters. An equivalent consideration and/or treatment of the measured values M is also carried out for the second voltage measured values.

(12) For the computation of the electrical resistance, the arithmetic mean of the qualified measured values M of the first voltage values is now subtracted from the arithmetic mean of the qualified measured values M of the second voltage values. This difference of the measured values M is then divided by the difference of the current values. The value thus ascertained for the electrical resistance of the electrical component has a very high measurement accuracy which is still corrupted, if at all, only to a very limited extent by electromagnetic interference.

(13) The influence of systematic and random error sources can be minimized by this method. It is to be expressly noted that other electrical parameters for a plurality of electrical components are also measurable and/or determinable by the same method.

(14) Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and illustrative examples shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.