CN106716168B

CN106716168B - Battery management system and method for calibrating sensors of a battery management system

Info

Publication number: CN106716168B
Application number: CN201580053623.8A
Authority: CN
Inventors: J.贝克; J.扎尔齐格; M.吕格; T.察费里迪斯; A.伯姆; M.伯格
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2014-10-02
Filing date: 2015-08-07
Publication date: 2020-09-22
Anticipated expiration: 2035-08-07
Also published as: CN106716168A; DE102014220079A1; WO2016050403A1

Abstract

The invention relates toAnd a battery management system (1) and a method for calibrating a sensor of a battery management system (1), wherein the sensor is adapted to detect a charging parameter when charging an associated battery (2) at a charging station (3). According to the invention, the charging voltage U is charged by the charging station (3)_Station(5) A charging current I emitted in the case of_Station(4) When the battery pack (2) is charged, the charging current I is detected by the charging station (3)_Station(4) And/or charging voltage U_Station(5) Measuring the current I by charging a sensor of a battery management system (1)_BMSOr charging measurement voltage U_BMSDetecting a charging parameter from the charging measurement current I_BMSAnd a charging current I_StationMeasuring voltage U in or from charging_BMSAnd a charging voltage U_StationAnd using the determined measurement difference as a sensor correction value for calibrating the sensor.

Description

Battery management system and method for calibrating sensors of a battery management system

Technical Field

The invention relates to a method for calibrating sensors of a battery management system during charging of an associated battery at a charging station. The invention further relates to a battery management system for a battery system having a battery, wherein the battery management system has a sensor which is suitable for detecting a charging parameter when charging the battery at a charging station.

Background

Battery packs (often in lithium-ion technology) are used in hybrid and electric vehicles, which consist of a large number of electrochemical cells connected in series. Battery management systems (battery packs) are used to monitor battery packs (also referred to below as battery packs) and should ensure as high a lifetime as possible in addition to safety monitoring.

The battery management device has different sensors for measuring e.g. current, voltage and temperature. A current sensor for measuring the current flowing through the battery pack should take a large meaning, since the current value determined by the current sensor is usually used to determine the State of Charge (SOC). Here, the more accurately the current actually flowing can be measured by the current sensor, the more accurately the state of charge of the battery pack can be measured.

Furthermore, the continuous current emitted by the battery pack and the peak current are often monitored by means of current sensors, the monitoring of the peak current being safety-relevant and the magnitude of the peak current (hhine) being decisive for the assurance of a warranty service (garnetieleastung) (ausschlagegebend). The more accurately the current that can be emitted by the battery can be determined, the smaller the safety buffer can be selected for compensating possible measurement errors.

Furthermore, battery packs frequently have a voltage sensor for determining the pack voltage, which can be used for plausibility checking of the sum of the voltages of the electrochemical cells connected in series. Furthermore, the battery pack may have a voltage sensor for determining a link voltage (Linkspannung), which may be measured on the grid connection side after a contactor via which the grid may be connected to the battery pack. Based on a possible difference between the packet voltage and the link voltage, the contactor may be diagnosed.

Such voltage sensors are typically installed in the battery pack calibrated at the time of manufacture of the battery pack. Any further calibration to compensate for possible sensor value deviations caused by aging generally does not take place thereafter.

A method and an energy storage device for detecting an abnormality of a current sensor of a vehicle are known from JP 2013090473. To this end, the regulator compares the detection value of a first current sensor in the energy storage device with the detection value of a second current sensor in a charging device located on board the vehicle, which is powered by an external energy source via a charging cable.

JP 2012 and 080712 describe a vehicle charging device operating on a vehicle, wherein the vehicle charging device is capable of charging a vehicle battery pack even if a sensor provides an abnormal value. The vehicle charging device has sensors on the input side and on the output side, the values of which are compared by an error detection device in order to detect detection errors in this way.

The amount of charge (Ladungsmenge) transferred from the energy source during charging of the battery pack is determined by the product of the charging current and the associated charging voltage, which is integrated over time. The charging current and the charging voltage are therefore also referred to collectively as charging parameters in the following. Further, hereinafter, the current and voltage detected by the sensor of the battery pack management system will be referred to as I_BMSAnd U_BMSAnd the current and voltage measured by the stationary charging station is referred to as I_StationOr U_Station。

Disclosure of Invention

According to the invention, a method for calibrating a sensor of a battery management system is provided, wherein the sensor is suitable for detecting a charging parameter when charging an associated battery at a charging station. In this case, the charging voltage U is used by the charging station_StationA charging current I emitted in the case of_StationWhile charging the battery pack, (I) detecting the charging current I by the charging station_StationAnd/or charging voltage U_Station(ii) measuring the current I with charging by a sensor of the battery management system_BMSOr charging measurement voltage U_BMS(ii) detecting a charging parameter, (iii) measuring the current I from the charging_BMSAnd a charging current I_StationMeasuring voltage U in or from charging_BMSAnd a charging voltage U_Station(iii) determining (emittelt) the measurement difference, and (iv) using the determined measurement difference as a sensor correction value for calibrating the sensor.

Such an approach provides a number of advantages. A first advantage is that the sensors of the battery management device can be verified. In charging stations, in particular for hybrid or electric vehicles, an accurately determined charge quantity is also emitted, in particular for settlement purposes (abechnnsgzwecken). For this purpose, sensors for determining the charge quantity, i.e. for determining the charging current emitted and the charging voltage U present there, must be detected_StationThe sensor of (1). Such verification (Eichung) can usually be ensured on the operator side of the charging station, for example by periodic inspection. In the method according to the invention, the current I is measured from the charge determined by the battery management system_BMSAnd a charging current I_StationMeasuring voltage U during or from charging determined by the battery management system_BMSAnd a charging voltage U_StationThe difference in measurement was determined. The determination of the difference thus allows the value determined by the sensor of the battery management system to be compared with the value determined by the charging station, the latter being intended to have a high reliability as a result of the verification of the charging station. Thus, all sensors of, for example, a vehicle battery are commonly subjected to environmental influences acting on the vehicle. Advantageously, the method allows comparison with a current reference or a voltage reference which is not part of the battery management device and which, in the case of a vehicle battery, is not located on the vehicle and which is furthermore usually certified.

A further advantage of the method is that sensor errors can be reliably detected, wherein the checking of the sensor can be carried out with each charging of the battery pack. The method according to the invention therefore offers the advantage of periodic sensor diagnostics, without additional expenditure in time being required for this.

Furthermore, the method according to the invention offers the following advantages: the sensors of the battery management system can be checked regularly, i.e. each time the battery is charged, and can also be calibrated. The calibration is also carried out without additional time expenditure, i.e. in the case of a vehicle battery, for example, without visiting a workshop. A series of further advantages result from the frequent execution of the method, i.e. from the frequently (h ä ufig) checked, possibly recalibrated and thus reliably measured sensors of the battery management system. The State of Charge SOC (State of Charge) of the battery pack can thus be determined accurately, which allows an accurate statement about the available residual Charge or the possible residual power. Further, the State of Health SOH of the battery pack can be determined more accurately. And furthermore the accurate measurement allows a reduction of safety tolerances. Furthermore, a fine difference between the voltages determined by the battery management system, for example between the link voltage and the pack voltage, can be determined more precisely, as a result of which a diagnosis inside the battery, for example for contactor diagnosis, can be made more precisely.

The method is advantageously carried out such that the value of the charging parameter is transmitted from the charging station to a battery management system of the battery, and the battery management system performs the calculation of the measurement difference. Such an embodiment allows the method to be carried out efficiently, since only a unidirectional data transmission method is required for the method for transmitting data from the station to the battery pack. In an alternative embodiment, the charging measurement current I_BMSOr charging measurement voltage U_BMSFrom the battery pack, these are transmitted to the charging station in order to calculate the difference there, and the measured difference or the sensor correction value must be transmitted to the battery pack in a further transmission by means of a bidirectional data transmission method.

Advantageously, the transmission is secured by a Handshake protocol (Handshake-Protokoll). The handshake is generally understood as a handshake (Quittungsbetrieb). In the corresponding handshake method, the two participants involved in the data transmission are synchronized after each transmission process by a direct acceptance signal. Since the measurement of the sensitive battery characteristic variables is interfered with by the method, erroneous transmission of the charging parameters, which may lead to incorrect calibration, can have serious consequences. The transmission of the charging parameters is therefore advantageously recognized by the battery pack. Furthermore, the transmission is advantageously carried out in such a way that the received value is transmitted back to the sender or that the information, for example the check digit, is used so that the correctness of the received data can be verified.

The method is advantageously carried out such that the value of the charging parameter changes over time and a sensor correction value is determined for different values of the charging parameter. Since the sensor error does not have to be constant over the value range of the variable detected by the sensor, such an embodiment allows a value table (also called lookup table) or a correction characteristic curve to be created, from which a corrected sensor value can be assigned to each measured sensor value.

The value of the charging parameter is advantageously varied continuously or stepwise. Such an implementation allows first transmitting with each step a value of the charging parameter, which is set by the charging station at a later time interval. By repeating this procedure, the correction characteristic curve can be measured step by step. Alternatively or additionally, the charging parameter is continuously changed, wherein the value of the charging parameter detected at the charging station is continuously transmitted to the battery management system by transmission (quasi). Thus, for example, a constant charging current I_StationCausing a continuously rising charging voltage U_Station. Charging voltage U_StationAllows the associated continuous charging measurement voltage U to be determined in the battery management system_BMS。

Advantageously, the charging parameters are only changed stepwise after a successful handshake, since incorrect assignment of the assumed, if appropriate previously set charging parameters to the charging parameters actually set by the charging station may lead to incorrect calibration.

The method is advantageously performed such that the measurement difference is compared to a threshold value, wherein an error is signaled when the threshold value is exceeded (Fehlersignalisierung). Performing the method in this way allows errors in calibration and sensor defects to be determined and signaled. In the case of the method being performed in a vehicle battery, the presence of an error can be signaled to the driver (/ the female driver).

Advantageously using the charging voltage U_StationThe method is performed as a charging parameter. When the method is carried out in this way, the charging voltage U_StationFor example to a battery pack. Battery management system for a battery, for determining a charging measurement voltage U via a voltage sensor to be calibrated_BMSAnd calculates the associated measurement difference Δ U. The measured difference Δ U is stored and used as a sensor correction value U Δ. This is done, for example, by correlating the sensor correction value UΔ with the voltage U measured by the sensor_BMSThe values of (a) are added. Advantageously, the voltage value U is not the only one_BMSInstead, a sensor correction value U Δ is determined for at least one section of the range of voltage values.

If the charging voltage U is increased, for example, stepwise, by means of a charging station_StationThen for the corresponding charging voltage U_StationDetermining the respectively associated measurement difference Δ U, wherein for each charging voltage U_StationSetting the associated charging current I_Station. The measured difference DeltaU is corrected by a sensor to obtain a characteristic curve UDeltaU (U)_BMS) Is stored such that for the value U determined by the voltage sensor_BMSAn associated sensor correction value U Δ is provided.

Advantageously using the charging current I_StationThe method is performed as a charging parameter. When the method is carried out in this way, the charging current I_StationFor example to a battery pack. Battery management system for a battery, for determining a charging measurement current I via a current sensor to be calibrated_BMSAnd the associated measurement difference Δ I is calculated. The measured difference Δ I is stored and used as a sensor correction value I Δ. This is done, for example, by comparing the sensor correction value I Delta with the current I measured by the sensor_BMSIs added toThe process is carried out. Advantageously, the current value I is not the only current value_BMSInstead, a sensor correction value I Δ is determined for at least one section of the value range of the current value.

If the charging current I is increased, for example, stepwise, by means of a charging station_StationBy making the charging voltage U, for example_StationIncreasing or decreasing until the associated charging current I occurs_StationThen for the corresponding charging current I_StationThe respective associated measurement differences Δ I are determined. The measured difference Δ I is corrected by a sensor to obtain a characteristic curve I Δ (I)_BMS) Is stored so as to be specific to the value I measured by the current sensor_BMSAn associated sensor correction value I Δ is provided.

Advantageously using a negative charging current I_StationOr a discharge current as a charging parameter. By e.g. applying a charging voltage U_StationLowering the charging current I below the pack voltage or below the link voltage may be achieved_StationThe reversal into a discharge current via which the sensor correction characteristic curve I Delta (I Delta) can be determined in the same manner_BMS)。

A method for calibrating a sensor of a battery management system, which sensor is used for determining the capacity of a battery, is advantageously performed. Determining a capacity based on sensors calibrated via the method allows for an accurate determination of a magnitude of the capacity, which allows for an accurate calculation of a usable range (Reichweite) or a remaining range of a hybrid or electric vehicle, for example.

In a battery management system according to the invention for a battery system having a battery, wherein the battery system has a sensor which is suitable for detecting a charging parameter when charging the battery at a charging station, provision is made for: the battery management system is designed to (i) read in a charging voltage U detected outside the system by means of a charging station when charging the battery_StationAnd/or a charging current I detected outside the system_Station(ii) detection as a charging parameter via a sensorCharging measurement current I_BMSOr charging measurement voltage U_BMS(iii) measuring the current I from the charge_BMSAnd a charging current I_StationMeasuring voltage U in or from charging_BMSAnd a charging voltage U_Station(iii) determining the measured difference, and (iv) using the determined measured difference as a sensor correction value for calibrating the sensor. The battery management system is in particular a battery management system for performing the above mentioned method.

Drawings

The invention is further elucidated in accordance with a preferred embodiment with reference to the accompanying drawings.

Fig. 1 shows an example of an arrangement of a battery system at a charging station for carrying out the method according to the invention;

FIG. 2 shows the charging current I when carrying out an embodiment of the method according to the invention_StationAnd a charging measurement current I_BMSAn example of a time varying process of (a);

FIG. 3 shows the sensor correction value I Δ and the charge measurement current I_BMSExamples of related functions;

fig. 4 shows the charging voltage U when carrying out an embodiment of the method according to the invention_StationAnd a charging measurement voltage U_BMSAn example of a time varying process of (a);

FIG. 5 shows the sensor correction value UΔ and the charge measurement voltage U_BMSExamples of related functions.

Detailed Description

Fig. 1 shows an example of an arrangement for carrying out a battery pack system 10 at a charging station 3 according to an embodiment of the method according to the invention.

The battery pack system 10 has a battery pack 2, and the battery pack 2 is managed by a battery pack management system 1. For this purpose, the battery management system 1 has a plurality of sensors (not shown here) for detecting a voltage, for example as a voltage detection pack voltage on the battery pack, or for example as a voltage detection link voltage at the consumer output of the battery pack 2.

From the charging station 3 viaThe charging cable 12 charges the battery pack system 10. Here, at a charging voltage U _Station5 charging current I emitted by the charging station 3_Station4 flow in the charging cable 12. Charging current I_Station4 and a charging voltage U _Station5 can be set by the regulating device 11 in the charging station 3. Charging voltage U _Station5 and charging current I_Station4 are detected in the charging station 3 by the certified measuring devices I and U.

Furthermore, a data connection 13 is present between the charging station 3 and the battery system 10, in particular between the charging station 3 and the battery management system 1 of the battery 2. The data connection 13 can be implemented not only wirelessly but also as a line. The charging parameters (for example the charging current I) can be coupled via a data connection 13_Station4 or charging voltage U_Station5) Is transmitted from the charging station 3 to the battery management system 1 of the battery 2. The transfer may be secured (abdesichert) by a handshake protocol between the battery management system 1 and the regulating device 11. The regulating device 11 is designed to temporally vary a charging parameter, i.e. a charging current I_Station4 or charging voltage U _Station5 and the changed value is transmitted to the battery management system 1 via the data connection 13. The battery management system 1 is set up to determine sensor correction values for different values of the charging parameter and to use the sensor correction values for calibrating the sensors.

The method is carried out with the device in such a development that the value of the charging parameter is changed continuously or stepwise by the control device 11. Only after a successful handshake does the charging parameters change accordingly.

After a successful handshake, the charging current I shown in fig. 2 is supplied via the regulating device 11 of the charging station 3_Station4 as charging parameters are changed or reset. On the battery management system 1 side, the charging measurement current I, which is likewise shown in fig. 2, is then measured by the current sensor to be calibrated_BMS6, measurement was carried out.

Alternatively, the charging station shown in fig. 4 is charged by the regulating device 11 of the charging station 3Press U _Station5 as charging parameters are changed or reset. On the battery management system 1 side, the charge measurement voltage U, which is likewise shown in fig. 4, is measured by a voltage sensor to be calibrated_BMS7, the measurement was carried out.

Battery management system 1 measures current I from charging_BMS6 and charging current I_Station4, or measuring voltage U from charging_BMS7 and a charging voltage U_StationIn 5, measurement differences 8, 9 are determined, which are used as sensor correction values I Δ for calibrating the current sensor to be calibrated or as sensor correction values U Δ for calibrating the voltage sensor to be calibrated.

FIG. 2 shows the charging current I when carrying out an embodiment of the method according to the invention_Station4 and a charging measurement current I_BMS6, in which the charging current I_Station4 are increased stepwise, here at intervals of 20A.

FIG. 3 shows the sensor correction value I Δ and the charge measurement current I_BMS6 example of a function related. To create this function, the charging current I_Station4 are increased in steps of 20A (Schritten) as shown in fig. 2, and the corresponding charging measurement current I_BMS6 was measured. Measuring current I with respect to charging_BMS6 depicts at charging current I_Station4 and a charging measurement current I_BMS6. At a charging current I_StationWhen 4 is 60A, the battery management system 1 measures a charge measurement current I of 65A_BMS6. Charging current I_Station4 and a charging measurement current I_BMSThe difference between 6 measures the current I for a charge of about (bei) 65A_BMS6 is therefore-5A. If the battery management system 1 detects a current value of 65A, then-5A is added to the current value as a sensor correction value. Because there is no continuous slave charging current I_Station4 and a charging measurement current I_BMS6, the value is determined, so that the current I is measured during charging_BMS6 interpolates the sensor correction value I Delta (I) between the given values_BMS)。

FIG. 4 shows the charging voltage U _Station5 and a charging measurement voltage U_BMS7. Because of the charging voltage U _Station5 and a charging measurement voltage U_BMS7 continuously rises as the state of charge SOC increases, so the curve shows a continuous course of change. Here, the charging voltage U _Station5 and a charging measurement voltage U_BMS7 by frequently charging the voltage U _Station5 are communicated to the battery management system 1 to be measured approximately synchronously. This also corresponds to a stepwise change of the charging parameter, wherein the step distance is selected to be small.

FIG. 5 shows the sensor correction value UΔ and the charge measurement voltage U_BMS7 example of a function related. The sensor correction value I Δ (I) in fig. 3 is compared with this_BMS) Similarly, the sensor correction value Udelta (U) is determined_BMS). Unlike in the case of fig. 3, the charging voltage U is applied_Station5 are changed continuously or in small steps such that the associated sensor correction value U Δ (U) is changed_BMS) Measuring the voltage U for each charge_BMS7 is available.

Claims

1. Method for calibrating a sensor of a battery management system (1), wherein the sensor is suitable for detecting a charging parameter when charging an associated battery (2) at a charging station (3), characterized in that a charging voltage U is used by the charging station (3) at a charging voltage U_Station(5) A charging current I emitted in the case of_Station(4) When the battery pack (2) is charged,

-detecting the charging current I by the charging station (3)_Station(4) And/or the charging voltage U_Station（5），

-measuring a current (6) or a voltage U by charging with the sensor of the battery management system (1)_BMS(7) Is detected as a form of the charging parameter,

-measuring a current I from said charging_BMS(6) And the charging current I_Station(4) Measuring voltage U in or from said charging_BMS(7) And the charging voltage U_Station(5) Measure the differences (8), (9), and

-using the measured difference (8), (9) as a sensor correction value for calibrating the sensor.

2. Method according to claim 1, the value of the charging parameter being transmitted from the charging station (3) to the battery management system (1) of the battery (2), and the battery management system (1) performing the calculation of the measured difference (8), (9).

3. The method according to claim 2, said transmission being guaranteed by a handshake protocol.

4. The method of claim 2, wherein the value of the charging parameter changes over time, and the sensor correction value is determined for different values of the charging parameter.

5. Method according to claim 4, characterized in that said value of said charging parameter is changed continuously or stepwise.

6. A method according to claim 5, characterized in that the charging parameters are changed stepwise only after a successful handshake according to claim 3.

7. Method according to one of claims 1 to 6, characterized in that the measured difference (8), (9) is compared with a threshold value, wherein an error is signaled when the threshold value is exceeded.

8. Method according to one of claims 1 to 6, characterized in that the charging voltage U is used_Station(5) The method is performed as a charging parameter.

9. According to claimMethod as claimed in one of the claims 1 to 6, characterized in that a charging current I is used_Station(4) The method is performed as a charging parameter.

10. Method according to one of claims 1 to 6, characterized in that a negative charging current I is used_Station(4) Or the discharge current as a charging parameter.

11. Battery pack management system (1) for a battery pack system (10) having a battery pack (2), wherein the battery pack management system (1) has sensors which are suitable for detecting charging parameters when charging the battery pack (2) at a charging station (3), characterized in that the battery pack management system (1) is set up for,

-reading in a charging voltage U detected outside the system when charging the battery pack (2) by means of a charging station (3)_Station(5) And/or a charging current I detected outside the system_Station(4) The value of (a) is,

-detecting a charge measurement current I as a charge parameter via the sensor_BMS(6) Or charging measurement voltage U_BMS（7），