KR102039444B1

KR102039444B1 - Method for determining a charge state

Info

Publication number: KR102039444B1
Application number: KR1020157016796A
Authority: KR
Inventors: 크리스텔 자페어트; 위르겐 모츠; 잉고 코흐; 토르스텐 베얼레; 마르틴 홀거 쾨닉스만; 에버하르트 쇼흐; 가보르 바라니
Original assignee: 로베르트 보쉬 게엠베하
Priority date: 2012-12-27
Filing date: 2013-10-24
Publication date: 2019-11-26
Also published as: KR20150102016A; EP2939037A1; WO2014102021A1; JP6141450B2; DE102012224417A1; JP2016509207A; CN104871023A; CN104871023B

Abstract

The present invention relates to an apparatus (2) and a method for determining the state of charge of an electrical energy storage device when the electrical energy storage device (4) is charged with electrical energy during the charging process. A property map is determined based on one or more values for current integration as one or more input parameters and one or more values for one or more additional input parameters.

Description

How to determine charge status {METHOD FOR DETERMINING A CHARGE STATE}

The present invention relates to a method and apparatus for determining the state of charge.

The state of charge (SOC) of a battery is generally determined by the integration of the current flowing through the battery over time. However, for the integration, one or more initial values of the battery charge must be known. In order to be able to compensate for drift due to measurement tolerances, recalibration of the state of charge may be performed at certain time intervals. This is done by measuring the idle potential while the battery is at rest and only a small load current flows through the battery. In addition, if the battery is sufficiently charged with electrical energy after one charging process, a buffer state may be detected.

German publication DE 10 2006 036 784 A1 uses a state variable and parameter estimator that calculates state variables and parameters of a mathematical model of an energy storage device from various operating variables of a battery. A method for determining the capacity of a battery is described. Here, the state of charge of the battery can be determined very accurately when the capacity of the battery during normal battery operation is calculated as a function of one or more capacity dependent parameters.

On this basis a method and apparatus with the features of the independent claims are proposed. Other embodiments of the invention refer to the dependent claims and the following description.

In an embodiment of the method, the state of charge (SOC) of the electrical energy storage device is determined during the charging process of the electrical energy storage device using the electrical energy. In this case, the state of charge can be determined even when the charging process for the energy storage device has not been completed so that the buffer state for the energy storage device has not been reached. In the method described below, the electrical energy storage device is generally referred to as a battery, which can be formed, for example, as a lead-acid accumulator of an automobile and / or as a starter battery thereof. However, the method herein can be performed on any electrical energy storage device that is rechargeable after discharge.

The method herein can be carried out in particular for one or more electrical energy storage devices of a motor vehicle, and is also suitable for a motor vehicle equipped with a hybrid drive device, wherein the electric motor of the motor vehicle receives electric energy from this type of electric energy storage device.

In the case of automobiles, one or more electrical energy storage devices of a vehicle are charged by the conversion of mechanical energy into electrical energy, for example by a generator formed as a dynamo and / or by an electric motor operated as a generator during the braking process.

In this case, however, the charging time provided for this may be limited to an average of 20 to 30 minutes of driving time, whereas the driving time required for the cushioning may correspond to 3 to 4 hours depending on each state of charge. Consideration should be given. In addition, it must also be taken into account that the state of charge is intentionally kept below 100% due to the energy management of the vehicle. In addition, depending on each type of use of the vehicle (eg taxi), a rest stage in which the rest voltage of the battery can be determined may not occur over a relatively long time. In this case, the possibility of charge state recalibration is further provided in the scope of the method, thereby increasing the availability and accuracy of the state of charge to be determined.

Various measures may be taken when implementing the method for determining the state of charge of the electrical energy storage device during the charging process. During the charging process, values for one or more related operating parameters and / or one or more related measurement variables of the battery may be detected as one or more input parameters. As such, the charging state may be detected based on the battery current Ibatt flowing through the battery and / or the battery voltage Ubatt applied to the battery as one or more input parameters.

Input data for the values of one or more detected measurement variables and / or one or more detected operating parameters, calculated during one possible performance of the method, can be examined in relation to their validity range and consistency. The state of charge can be determined via a characteristic map, for example by comparison and / or calculation, based on input data for one or more detected measurement variables and / or values of one or more detected operating parameters.

In a first step of one embodiment of the method of the present invention, detection of the charging state of the battery may be performed based on the battery current Ibatt and / or the battery voltage Ubatt as operating parameters. In this case, the actual values for the electrical operating parameters can be compared with the threshold value Ibatt_load for the battery current and the threshold value Ubatt_load for the battery voltage provided for this purpose. When Ubatt> Ubatt_load and Ibatt> Ibatt_load, the battery is determined to be charged. To this end, the input signals for the actual values of the electrical operating parameters can be prefiltered to prevent unwanted interferences.

Detection of relevant measurement variables and battery parameters is performed during the charging process in the second step of the method. For the determination of the state of charge of the battery, the so-called charging acceptance of the battery during the charging process, ie the ability of the battery to accept electrical energy and to be charged with electrical energy, is calculated. Charge importability and all related operations and / or are generally dependent on operating parameters such as voltage, temperature of the battery and state of charge, which are applied during the charging process and may also be referred to as battery voltage or charging voltage. Alternatively, the charging state may be determined again by determining the peripheral parameters.

For one possible implementation of the method, for example, in one experiment, all input parameters related to the charging process, including the operating and / or ambient parameters, are detected and the relevant characteristic map for the state of charge according to the input parameters This can be determined.

As values for the input parameters, the value of the first current integral Q5 relative to the battery current Ibatt that flowed for the last 5 minutes, the second current integration Q10 for the battery current Ibatt that flowed for the last 10 minutes , The value of the third current integration Q15 for the battery current Ibatt that has flowed for the last 15 minutes, here at least one value for the charging voltage corresponding to the battery voltage Ubatt, for the temperature Tbatt of the battery One or more values and one or more values for the rated capacity C20 of the battery may be used.

The charge importability of the battery can be described by the value of the current integrals Q5, Q10, Q15. Alternatively or in addition, various input parameters may be used to express charge importability, for example through values of the battery current Ibatt flowing through the battery during the charging process, provided that the values provided for these are at different specific points in time. Can be detected.

In one variant of the method, the values of the mentioned current integrals Q5, Q10, Q15 are used in place of the battery current Ibatt, because the battery current may be transient or abnormal in some cases in an automobile. This can be caused by non-steady behavior, and as a result the state of charge can be determined relatively inaccurately. Of course, the battery current Ibatt for a plurality of time intervals can be measured to determine the average value of the battery current Ibatt for each time interval as a value. By providing an integral calculation to supply the values for the current integrals Q5, Q10, Q15, good filtering of the input parameters to be used can be achieved.

A check of its validity and consistency with the validity of the input data as values for the input parameters and the validity thereof is carried out in the third step. Here, it is checked whether the values of the input parameters are within the validity of the property map over a given measurement time and / or are stable enough, for example, continuous, to yield acceptable results for the state of charge to be determined. To this end, the value ranges of the input parameters as well as their minimum values and their maximum values are examined. The state of charge can be calculated if the value ranges of the input parameters as well as their minimums and their maximums are within preset thresholds.

Determination of the state of charge may be performed through the property map based on the input parameters in the fourth step of the present method. In this case, a multidimensional characteristic map is used based on the values of input parameters determined based on experience. In brief, the characteristic map may be provided through linear regression of the detected and / or calculated values of the input parameters, which may be generally performed in a resource friendly manner. However, nonlinear approaches can also be used to determine the characteristic map, if desired.

By means of the characteristic map, various values of state of charge (SOC) can be calculated which depend on different values of the input parameters. The relationship between the values of the state of charge (SOC) can be expressed through the following regression equation (1).

In the above equation, c1, c2, c3, c4, c5, c6, c7, c8 and c9 are measured data and / or measured values of the input parameters described below (Ubatt, Tbatt, C20nom, Uc0max, C0 , Q5, Q10 and Q15) are regression coefficients that can be determined using the least squares method. By regression coefficients c1, c2, c3, c4, c5, c6, c7, c8 and c9, generally ci, the values Ubatt, Tbatt, C20nom, Uc0max, C0, Q5, Q10 and Q15 are scaled Can be.

Ubatt is herein a value of the battery voltage measured in volts (V), corresponding to the charging voltage. Tbatt is the value of the battery temperature measured in Kelvin (K). C20nom is the nominal value of the battery rated capacity (C20) in ampere hours (Ah). Uc0max is the value of the battery maximum idle voltage in volts. C0 is a value for the reserve capacity of the battery acid of the battery, specified in units of parrot (F). Q5, Q10 and Q15 represent the value of the current integration over the current Ibatt of the battery, where Q5 corresponds to the value of the current integration over the current flow for 5 minutes, and Q10 for the current integration over the current flow for 10 minutes Corresponding to the value of, Q15 corresponds to the value of the current integration over the current that flowed for 15 minutes, the values for these current integrations are specified in ampere seconds (As).

The regression equation (1) mentioned here contains only the linear terms (c * x) of the value (x) for the input parameter. Possible extensions include higher orders, e.g., quadratic (ci * x ² ) of the value (x) for the input parameter and the terms of the square, and / or nth or n for the value (x) of the input parameter. Terms of power (ci * x ⁿ ) are also possible. In addition, the interaction of the values x and y of different input parameters by the regression equation (1), for example (ci * x * y), can also be used. Typically any other methods for approximation of the characteristic map may also be used, such as neural networks or splines.

In regression equation (1) all important operating parameters used as input variables are taken into account. Regression equation (1) may be supplemented by values for additional input parameters that are scaled through regression coefficients (ci).

The input parameters can be mutually calculated to provide a characteristic map by the regression equation (1). By means of the regression equation (1) used for the calculation of the state of charge, the regression dependence on the individual values of the input parameters together with the regression coefficients (ci) and their weighting coefficients are also taken into account.

Further advantages and configurations of the present invention refer to the specification and the accompanying drawings.

The foregoing features and features to be further described below may be applied within the scope of the present invention, either alone or in combination in other ways, as well as in the specified combinations.

1 is a schematic diagram of one embodiment of a proposed apparatus, formed to perform one embodiment of the method described above.
2 is a flowchart for performing an embodiment of the method described above.

The invention is schematically illustrated in the drawings on the basis of one embodiment, which is described in detail below with reference to the drawings.

In FIG. 1, one embodiment of a device 2 formed here to determine the state of charge of an electrical energy storage device formed as a battery 4 is shown schematically. In the implementation of the method for determining the state of charge, a charging procedure is carried out for the battery 4. In this case, the poles of the battery 4 are connected with an electrical energy source via supply lines 6, 8.

The apparatus 2 comprises a control unit 10 and an electrical measuring unit 12. To determine the state of charge, here, as one or more electrical input parameters, the battery current Ibatt flowing through the battery 4, the battery voltage Ubatt applied to the battery 4, and / or the temperature of the battery Tbatt One or more values of) are detected in a sensory manner by the electrical measuring unit 12, wherein the measuring unit 12, as shown in FIG. 1, of the battery 4 via measuring lines shown here as dashed lines here. One or more poles and / or one or more supply lines 6, 8. The measurement of the battery current Ibatt is not clearly shown in FIG. 1. In the illustrated embodiment, the battery current Ibatt flows through the measurement unit 12, for example through a shunt (measurement resistance) arranged in the measurement unit 12. Alternatively, the battery current Ibatt flowing through the measuring unit 12 may be inductively measured in the measuring unit 12. In this case, the detected values for the input parameters are passed to the control unit 10 for further evaluation, that is to say for the determination of the state of charge, which is evaluated by this control unit.

The individual steps 14, 16, 18, 20 for carrying out the method herein using the embodiment of the device 2 shown here are shown in the flowchart of FIG. 2.

In a first step 14, the battery is based on one or more input parameters, here one or more values of current integration, and on the basis of the battery voltage Ubatt and / or the temperature Tbatt of the battery 4 during the charging process. The state of charge of (4) is determined. For this purpose, in particular, it is checked how higher or lower the value of one or more input parameters is than the threshold provided for it.

In a second step 16, during the charging process, one or more values of one or more input parameters, generally one or more peripheral parameters of the battery 4 and / or one or more operating parameters, are supplied to the electrical measuring unit 12. Is detected through the measurement.

In a third step 18, one or more values of one or more input parameters are checked for validity, eg validity and consistency.

In the final fourth step 20 of the method, a substantial determination of the state of charge of the battery 4 is performed when the battery is charged with electrical energy during the charging process. In this case, the state of charge is determined via the property map based on one or more values for current integration as one or more input parameters, and one or more values for one or more detected input parameters.

In this case, the characteristic map may be determined a priori through a regression equation according to one or more values of one or more input parameters. In addition, the characteristic map is stored in the control unit 10. The regression equation used in this case represents the dependence of the state of charge on the values of the input parameters.

As a result, the current integration of the battery current Ibatt of the battery 4 is used as one or more input parameters, wherein one or more values of the current integration are calculated based on one or more input parameters measured during the charging process. One or more values of current integration are calculated here for the one or more time intervals for one or more time intervals. As one or more additional input parameters, the battery voltage and / or the temperature of the battery 4 is used. It is also possible to use the capacitance of the battery 4 and / or the idle voltage of the battery as one or more additional additional input parameters. It is also possible to use other operating parameters of the battery as input parameters. In this case, the values of the input parameters, that is, one or more values of the current integration and one or more values of the one or more additional input parameters can be calculated with each other. In addition, regression dependencies between the values of one or more input parameters may be used. Alternatively, or as a supplement, weighting coefficients for a linear relationship of one or more values of one or more input parameters may be used.

Typically one or more values of current integration are calculated through integration of battery current Ibatt detected by sensor sensing over time. In this case, for different time intervals, generally for different lengths of time, various current integration values can be used to determine the state of charge. The time intervals for which values for current integration are typically determined may be initiated at the beginning of the charging process and their length may be different from each other. In this example, n values of current integration can be determined for n different time intervals. The value of the current integration calculated during the time interval gives the value for the charge flowing into the battery 4 during that time interval.

The battery 4 in which the state of charge is determined in the scope of the method may be formed as a starter battery of a motor vehicle. In this case, the battery 4 may be a lead storage battery. As an alternative, the method herein can also be performed in the case of a battery 4 formed as a lithium ion accumulator.

It is also possible to determine when the battery 4 is fully charged by monitoring one or more values for current integration based on the flowing battery current Ibatt. For example, for a battery 4 formed as a lithium ion accumulator, the state of charge (SOC) can be estimated from one or more values of current integration during the charging process, since only a small loss is expected in this case. Using the method herein, the state of charge can be determined without further integration based on one or more values of the current integration and one or more values of the one or more additional input parameters already after a short time (eg 15 minutes) after the start of the charging process.

Claims

When the electrical energy storage device is charged with electrical energy during the charging process, a method for determining the state of charge of the electrical energy storage device,
The state of charge is determined through a characteristic map based on one or more values for the current integration of the current flowing in the electrical energy storage device as one or more input parameters and one or more values for one or more additional input parameters. At least one value for at least one input parameter is detected during the charging process.

The method of claim 1, wherein the charging situation of the electrical energy storage device is determined based on one or more input parameters during the charging process.

The method of claim 1, wherein the one or more values of the one or more input parameters are checked for validity.

3. A method according to claim 1 or 2, wherein the temperature of a battery is used as said one or more additional input parameters.

The method of claim 1, wherein a charge voltage is used as the one or more additional input parameters.

The method of claim 1, wherein the one or more values of the current integration are calculated during the one or more time intervals for one or more time intervals.

The method of claim 1, wherein the characteristic map is empirically determined according to the one or more input parameters.

The method for determining the state of charge of an electrical energy storage device according to claim 1, wherein the electrical energy storage device is formed as a lead storage battery.

A device for determining the state of charge of the electrical energy storage device when the electrical energy storage device is charged with electrical energy during the charging process,
The apparatus comprises a control unit 10,
The control unit 10 uses a characteristic map based on one or more values for the current integration of the current flowing in the electrical energy storage device as one or more input parameters and one or more values for one or more additional input parameters. Wherein the state of charge is determined and at least one value as the at least one input parameter is detected during the charging process.

10. Device according to claim 9, comprising one or more electrical measuring units (12) for detecting the one or more input parameters.

4. The method of claim 3 wherein the temperature of a battery is used as said one or more additional input parameters.

The method of claim 3, wherein a charging voltage is used as the one or more additional input parameters.

4. The method of claim 3, wherein one or more values of the current integration are calculated during the one or more time intervals for one or more time intervals.

The method of claim 3, wherein the characteristic map is empirically determined according to the one or more input parameters.

The method of claim 3, wherein the charging state determination method of the electrical energy storage device is performed on the electrical energy storage device formed as a lead storage battery.