DE102012019085A1 - Method for monitoring battery arrangement with multiple battery cells for battery system, involves executing control for operating battery arrangement, so that operating range of battery cells is maintained - Google Patents

Abstract

The method involves executing a control for operating a battery arrangement (2), so that an operating range of the battery cells is maintained. A parameter with respect to two predetermined parameter ranges is monitored. An error is determined when the parameter is more than a predetermined time period outside the former parameter range and within the latter parameter range. Independent claims are included for the following: (1) a device for monitoring a battery arrangement with multiple battery cells; and (2) a computer program product with a program code for executing the battery arrangement monitoring method.

Description

Technical area

The invention relates to battery arrangements with a plurality of battery cells and, in particular, to measures for increasing the service life of the battery cells in the battery arrangement.

State of the art

Battery arrangements for battery management systems are provided in particular from a plurality of battery cells, in particular lithium-ion cells, for use in electric or hybrid vehicles. In this case, the battery arrangements comprise series / parallel circuits of a plurality of battery cells.

Each of the battery cells must be operated to prevent damage or destruction and to protect against accelerated aging with respect to one or more operating variables within certain operating ranges. Thus, an operation of each of the battery cells with a cell voltage below a maximum voltage, the so-called charge end voltage, as well as above a minimum voltage, the so-called discharge voltage, advantageous since a long-term compliance with these operating conditions guarantees a maximum life of the battery cell. The same applies to the operating temperature of each of the battery cells, in each case depending on the type of battery cells, a temperature range exists in which a maximum life and protection against damage or destruction of the battery cell is ensured.

From the publication DE 10 2010 040 031 A1 is a monitoring of the voltage of a cell of a battery energy storage on an over and / or falling below a reference voltage known. Threshold monitoring determines whether the cell voltage is within a permitted range. If the voltage level of the cell is not within a predetermined voltage window, this is detected by an evaluation unit and a battery control can initiate appropriate measures to terminate this operating state, so that the voltage level is soon within a designated voltage window or voltage range.

By monitoring the single-cell voltages of different battery cells of a battery assembly, harmful or faulty operating states of the battery energy storage can be detected quickly. By appropriate measures, such as a shutdown of the battery energy storage or a part thereof, a complete, harmful discharge of at least a portion of the battery energy storage can be prevented.

From the publication EP 2 180 574 A2 a battery management system for monitoring and controlling a lithium-ion cell is known. By means of sensors, the voltage of the cell is determined, transmitted to the central control unit and forwarded to the data storage device. With the determined values, the battery management system is able to operate battery cells with the highest efficiency and to maximize the life of the battery cells. Battery cell parameters are detected, such as the temperature of the battery cells, electrical parameters of the battery cells, such as voltage, current, internal resistance, and the like. With the help of the battery cell parameters, the charging and discharging process of the battery cells is optimally controlled. Furthermore, the battery cells can be operated with the highest efficiency and the lifetime can be maximized.

From the publication DE 10 2007 038 532 A1 For example, a monitoring device for a battery arrangement with a plurality of battery cells is known, wherein each battery cell is assigned a monitoring circuit in order to monitor the function of the battery cell and to provide cell information dependent thereon. Depending on the cell information, a charging process is terminated or, in the case of a low charge state, a power requirement of a consumer is reduced.

From the publication DE 42 25 746 A1 a charge and discharge monitoring for battery assemblies is known. The charging and discharging monitor comprises, for each battery cell, a monitoring module having a charging current limiting circuit and a signal generator for indicating the operating state of the charging current limiting circuit. The discharge monitoring causes either a reduction of the discharge current or a separation of the load from the battery cells when an undervoltage occurs. If an overcurrent occurs during charging, the charger immediately switches back gradually until the overcurrent is reduced.

A disadvantage of the above battery management systems is that the limits of the operating quantities within which optimum operation of the battery cells is ensured are usually fluent and when defining a fixed window for the operating size often too far-reaching measures, such as switching off the battery assembly , which are generally inappropriate for the protection of individual battery cells and the usability of the Battery arrangement z. B. for traction applications.

It is an object of the present invention to provide an improved monitoring of a control for operating battery cells of a battery arrangement, in which a protective measure is taken only if it is necessary for the protection of the individual battery cells.

Disclosure of the invention

This object is achieved by the method for monitoring a controller for a battery assembly according to claim 1 and by the apparatus for monitoring a controller for a battery assembly and the computer program product according to the independent claims.

Further advantageous embodiments of the present invention are specified in the dependent claims.

• – Durchführen einer Regelung zum Betreiben der Batterieanordnung, so dass mindestens ein Betriebsbereich der Batteriezellen eingehalten wird;
• – Überwachen einer Betriebsgröße bezüglich eines ersten vorgegebenen Betriebsgrößenbereichs und eines zweiten vorgegebenen Betriebsgrößenbereichs; und
• – Feststellen eines ersten Fehlers, wenn die Betriebsgröße für mehr als eine vorgegebene Zeitdauer außerhalb des ersten Betriebsgrößenbereichs und innerhalb des zweiten Betriebsgrößenbereichs liegt.

According to a first aspect, a method for monitoring a control for a battery arrangement with a plurality of battery cells is provided, comprising the following steps:

• - Performing a control for operating the battery assembly, so that at least one operating range of the battery cells is maintained;
• - monitoring an operating variable with respect to a first predetermined operating range and a second predetermined operating range; and
• Detecting a first error when the operating quantity is outside the first operating range and within the second operating range for more than a predetermined period of time.

One idea of the above monitoring method is to monitor the function of a controller for operating a battery assembly, and in particular for charging and discharging. As a rule, the controller assumes the function of charging and discharging in such a way that no higher cell voltages than a final charge voltage are accepted during charging and no lower cell voltages than the final discharge voltage during discharge. Furthermore, the controller usually takes over a control of the cell current, so that a current limit is realized. Overall, the controller takes into account that operating variables are kept within respective predetermined battery cell individual operating ranges.

The above method now provides to monitor this control by providing a first operating size window having a first operating limit upper limit greater than an upper limit set by the controller for an operating quantity and a first operating magnitude lower limit less than a lower limit set by the controller Company size provides. The first operating variable range defined by the first upper operating limit and the first lower operating limit represents a safe operating variable range, wherein the battery cells within this first operating range of the battery assembly can be operated without damage or destruction, but a permanent operation within the first operating range but outside the control range gain acceleration of aging effects.

In addition, a second operating size upper limit and a second lower operating limit of a second operating size window are specified for the operating variable, which is greater than the first operating size upper limit or smaller than the first operating variable lower limit and which specify a second operating variable range. Although the battery cells can still be operated within this second operating variable range, even a short-term operation within the second operating variable range but outside the first operating variable range would result in an amplification or acceleration of aging effects. If the operating variable is outside the first operating variable range but within the second operating variable range for more than a predefined period of time, then a first fault is detected and a first error treatment is carried out.

While the controller already includes measures to interrupt a charging or discharging operation of the battery assembly, when the predetermined operation amount range between the end-of-charge voltage and the end-of-discharge voltage and between an upper temperature limit and a lower temperature limit or the like is exited, the above method is further Monitoring the operation of the controller, preventing inappropriate measures to protect the battery cells.

Furthermore, in the event of a fault, a circuit can be interrupted by the battery arrangement.

According to one embodiment, a second error may be detected as soon as the operating quantity is outside the second operating range. Thus, if the operating variable is outside the second operating variable range, a second fault is detected and a second error handling is performed. For example, in the second error handling the circuit immediately interrupted.

It can be provided that the operating variable comprises a cell voltage, a state of charge and / or a cell temperature.

The control for maintaining the operating ranges can generate a manipulated variable to keep the operating size within the operating range.

Furthermore, the operating range may be smaller than the first operating variable range and the second operating variable range may be greater than the first operating variable range. According to an embodiment, the control may be performed based on a plurality of operation quantities so as to maintain an operating range of the battery cells, wherein the operation amounts are monitored with respect to a respective first predetermined operation amount range and each second predetermined operation amount range, and a first fault is detected when a the operating variables lie outside the respective first operating variable range and within the respective second operating variable range for more than a respective, predetermined period of time.

• – eine Steuereinheit, die ausgebildet ist, um
• • eine Steuerung bzw. Regelung zum Betreiben der Batterieanordnung durchzuführen, so dass mindestens ein Betriebsbereich der Batteriezellen beibehalten wird;
• • die Betriebsgröße bezüglich eines ersten vorgegebenen Betriebsgrößenbereichs und eines zweiten vorgegebenen Betriebsgrößenbereichs zu überwachen; und
• • einen ersten Fehler festzustellen, wenn die Betriebsgröße für mehr als eine vorgegebene Zeitdauer außerhalb des ersten Betriebsgrößenbereichs und innerhalb des zweiten Betriebsgrößenbereichs liegt.

In another aspect, an apparatus for monitoring a battery array having a plurality of battery cells is provided, comprising:

• A control unit configured to
• • perform a control to operate the battery assembly so that at least one operating region of the battery cells is maintained;
• To monitor the operating quantity with respect to a first predetermined operating range and a second predetermined operating range; and
• • determine a first fault if the operating quantity is outside the first operating range and within the second operating range for more than a predetermined period of time.

In another aspect, a computer program product is provided that includes program code stored on a computer-readable medium and that, when executed on a data processing device, performs the above method.

Brief description of the drawings

Preferred embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. Show it:

1 a schematic representation of a battery management system with a battery assembly and a monitoring device for monitoring one or more operating variables of the battery cells of the battery assembly; and

2 a flowchart for illustrating a method for monitoring operating variables of a battery assembly.

Description of embodiments

1 shows a battery management system 1 with a battery assembly 2 and a control unit 3 for controlling charging and discharging operations of the battery assembly 2 ,

The battery arrangement 2 includes a series of battery cells 21 which are connected in series. Instead of individual battery cells 21 can each also be a parallel connection of battery cells 21 be provided with other parallel circuits of battery cells 21 is connected in series.

The battery cells 21 can be lithium-ion cells or other rechargeable battery cells 21 correspond, in particular battery cells, which can be used as a traction battery for operating an electric or hybrid vehicle.

It is a cell voltage measuring unit 4 provided the cell voltage of each of the battery cells 21 or each of the parallel circuits of battery cells 21 measures and corresponding cell voltage information, eg. B. as digitized voltage values, to the control unit 3 provides.

The control unit 3 has a first arithmetic unit 31 in which the cell voltage data from the cell voltage measurement unit 4 and that performs a control algorithm that ensures that each of the battery cells 21 when charging no higher cell voltage than a predetermined end-of-charge voltage and unloading assumes a lower cell voltage than a predetermined discharge end voltage. The control algorithm of the first processor 31 represents a manipulated variable S, for example, an indication of a charging or discharging current to be set to the environment of the battery management system 1 ready. It is envisaged that based on the manipulated variable S from an external system (not shown) one of the battery assembly 2 absorbed or provided current is maintained and thereby the cell voltages are kept in a predetermined by the control algorithm voltage operating range (operating range).

It is a shutdown element 5 provided with the control unit 3 connected is. The disconnection element 5 may be designed as a contactor, relay or other circuit breaker and is between the consumer and / or power generator and the battery assembly 2 provided a circuit through the battery assembly 2 to interrupt.

The control algorithm of the first processor 31 is designed to ensure a life-optimized operation of the battery cells 21 guaranteed. As long as the control algorithm works properly, the first computational unit issues 31 a first signal level (eg, a logical 1) of a first enable signal FS1, which is an AND gate 33 the control unit 3 provided. The signal level of the first enable signal FS1 indicates, when operated properly, that a circuit through the battery assembly 2 using the with the control unit 3 connected shutdown element 5 should be closed. If the control algorithm does not work properly, then the first arithmetic logic unit sets 31 the AND gate 33 a second signal level (eg, a logical 0) of the first enable signal FS1.

The control unit 3 also has a second processing unit 32 on which the correct function of the first arithmetic unit 31 controlled. For this purpose, the second arithmetic unit receives 32 also the cell voltage data from the cell voltage measuring unit 4 and determines whether the cell voltage data are each above a predetermined first cell voltage upper limit (first upper limit of operation) or below a predetermined first lower limit of the cell voltage (first lower limit of operation). The first cell voltage upper limit is above the end-of-charge voltage and the first cell voltage lower limit is below the end-of-discharge voltage and both define a first cell voltage range (first operational size range). Within the first cell voltage range and outside of the first arithmetic unit 31 To be observed control area, the battery cells 21 Although operated without damage, continuous operation due to increased aging effects is not desirable.

The second arithmetic unit 32 is designed to detect an undershooting of the first cell voltage upper limit or of the first lower cell voltage limit for more than a predefined voltage period. If such a case by the second processing unit 32 detected, so is a first signal level of a second enable signal FS2, the release, ie, a closing of the shutdown element 5 , signaled to a second signal level, the opening of the shutdown element 5 signaled, changed to the shutdown element 5 via the AND operation of the AND gate 33 to withdraw the release.

Furthermore, a monitoring unit 6 provided, as well as the cell voltage measuring unit 4 , the cell voltages of the individual battery cells 21 or the parallel circuits of battery cells 21 measures and provides a corresponding cell voltage indication. This can be done with the cell voltage measuring unit 4 or separately. The cell voltage indications become for each of the battery cells 21 with respect to a predetermined second cell voltage upper limit (second upper limit operating limit) and a predetermined second lower cell voltage limit (second lower operating limit), which indicate a second cell voltage range (second operating variable range).

The second cell voltage upper limit is higher than the first cell voltage upper limit and the second lower cell voltage limit is lower than the first cell voltage lower limit. The second cell voltage upper limit and the second cell voltage lower limit are selected to define, outside the first cell voltage range but within the second cell voltage range, an extended safe cell voltage range in which the battery cells 21 Although operation can be carried out, even a short-term operation would result in an amplification or acceleration of aging effects.

The monitoring unit 6 generates a third enable signal FS3, which is also the AND gate 33 is supplied and this indicates whether the shutdown 5 the circuit with the battery arrangement 2 close or open. If an overshoot or undershoot of the second cell voltage upper limit or the cell voltage lower limit is detected, then immediately a first signal level of the third enable signal FS3, which is a release, ie a closing of the shutdown element 5 signals, at a second signal level, an opening of the shutdown element 5 signaled, changed. Through the AND operation of the enable signals, the circuit is opened by the battery arrangement 2 using. of the shutdown element 5 as soon as at least one of the enable signals FS1, FS2, FS3 assumes the second signal level.

It is a cell temperature measuring unit 8th provided with first temperature sensors 9 at each of the battery cells 21 communicates to cell temperature specifications to the control unit 3 provide. Based on the cell temperature data, the first processor performs 31 the regulation of the operation of the battery arrangement 2 using the manipulated variable S off. The first arithmetic unit 31 provides the manipulated variable S thus ready so that a predetermined cell temperature upper limit not exceeded by one of the cell temperature information or a predetermined cell temperature lower limit is not exceeded by one of the cell temperature data, ie so that the cell temperature data remain within a predetermined temperature range. With proper behavior of the first processor 31 the first enable signal FS1 is set to the first signal level, otherwise it is changed to the second signal level.

Furthermore, the cell temperature specification of the second arithmetic unit 32 which checks whether the cell temperature indication is within a first temperature range defined by a predetermined first cell temperature upper limit and a predetermined first cell temperature lower limit. It is determined that the cell temperature indication for each of the battery cells 21 is outside of the predetermined first temperature range for more than a predetermined period of time, the second enable signal FS2 is changed from a first signal level to a second signal level to the circuit through the turn-off element 5 to interrupt.

The monitoring unit 6 is still with second temperature sensors 7 coupled to each of the battery cells 21 are arranged. Alternatively, the monitoring unit 6 also with the first temperature sensors 9 be connected. The monitoring unit 6 checks in each case the cell temperature and influences the third enable signal FS3, so that when a predetermined second cell temperature upper limit and falling below a predetermined second cell temperature lower limit, which define a second temperature range with each other, an immediate change of the signal level of the third enable signal FS3 to the second signal level.

In 2 Fig. 3 is a flow chart for illustrating the method of monitoring an operation amount such as the cell voltage or the cell temperature. In step S1, the operating variable is measured by a suitable measuring unit and then using the first processing unit 31 a control algorithm for controlling a charging or discharging operation using a manipulated variable S based on the measured operation size executed (step S2). Represents the first arithmetic unit 31 in step S3 determines that the control algorithm is working properly (alternative: yes), the process proceeds to step S4. Otherwise (alternative: No), the method continues with step S7.

In the second arithmetic unit 32 In step S4, it is checked whether the operation amount for each of the battery cells 21 each within a first operating range defined between a first operating size upper limit and a first operating size lower limit. If it is determined in step S4 that the operation amount for each of the battery cells 21 is outside the first operating range (alternative: No), the process proceeds to step S8. Otherwise (alternative: yes), the method continues with step S5.

In step S8, it is checked whether the operation amount for each of the battery cells 21 is outside the first operating range for more than a predetermined period of time. If this is the case (alternative: yes), the method is continued with step S7. Otherwise (alternative: No), the method continues with step S5.

The monitoring of step S5 provides a check as to whether the operation quantity BG for each of the battery cells 21 is within a second operating range, which is defined by the second operating limit and the second operating limit. If it is determined in step S5 that the operating variables are within the second operating variable range (alternative: yes), then the shutdown element 5 for closing the circuit of the battery assembly 2 controlled or the circuit with the battery assembly 2 remains closed (step S6). Subsequently, it returns to step S1.

If it is found in step S4 and S8 that at least one of the measured operating variables lies outside of the first operating variable range for a predetermined period of time, or in step S5 that at least one of the measured operating variables lies outside of the second operating variable range, in step S7 the enable becomes Closing of the circuit by the switch-off element 5 suspended and the circuit with the battery assembly 2 will be opened.

In step S4 can also be realized that under certain operating conditions, such. B. leaving operating ranges by a plurality of operating variables, the admission of the enable signal is withdrawn as soon as exceeding a charge end voltage or falls below a discharge end voltage is detected, but without the first operating size upper limit or the first operating variable lower limit was exceeded or fallen below.

That in the 2 described method can be realized simultaneously for different operating variables or together in a battery management system 1 be implemented. In particular, the cell voltage, the cell temperature, the state of charge of the cells and the like can be checked or monitored as operating variables.

The procedural steps relating to 2 can be explained in connection with 1 described battery management system are executed.

Furthermore, in conjunction with the battery management system 1 of the 1 described method steps with the reference to 2 be combined explained method steps.

LIST OF REFERENCE NUMBERS

1

Battery Management System

2

battery assembly

3

control unit

4

Cell voltage measuring unit

5

disconnection element

6

monitoring unit

7

second temperature sensor

8th

Cell temperature measuring unit

9

first temperature sensor

21

battery cell

31

first arithmetic unit

32

second arithmetic unit

33

AND gate

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010040031 A1 [0004]
• EP 2180574 A2 [0006]
• DE 102007038532 A1 [0007]
• DE 4225746 A1 [0008]

Claims (10)

Method for monitoring a battery arrangement ( 2 ) with several battery cells ( 21 ), comprising the following steps: - carrying out (S2) a control for operating the battery arrangement ( 2 ), so that at least one operating range of the battery cells ( 21 ) is complied with; - monitoring (S4, S5) an operating variable with respect to a first predetermined operating range and a second predetermined operating range; and - determining (S4, S8) a first fault if the operating variable is outside the first operating range and within the second operating variable range for more than a predetermined period of time. The method of claim 1, wherein upon detection of the first fault, a circuit through the battery assembly ( 2 ) is interrupted. The method of claim 1 or 2, wherein a second error is detected as soon as the operating variable is outside the respective second operating range. Method according to one of claims 1 to 3, wherein the operating variable comprises a cell voltage, a state of charge and / or a cell temperature. Method according to one of claims 1 to 4, wherein the control for maintaining the operating range generates a manipulated variable (S) in order to keep the operating variable within the respective operating ranges. The method of claim 5, wherein the operating range is smaller than the first operating range and the second operating range is greater than the first operating range. Method according to one of claims 1 to 6, wherein the control is carried out based on a plurality of operating variables, so that an operating range of the battery cells ( 21 ), wherein the operation quantities are monitored with respect to a respective first predetermined operation amount range and a respective second predetermined operation amount range, and wherein a first error is detected when one of the operation amounts is out of the respective first operation amount range and within the respective first operation amount range for more than a respective predetermined time period respective second operating range. Device for monitoring a battery arrangement ( 2 ) with several battery cells ( 21 ), comprising: - a control unit ( 3 ), which is designed to • control the battery arrangement ( 2 ), so that at least one operating range of the battery cells ( 21 ) is complied with; • monitor an operating variable in each case with respect to a first predetermined operating range and a second predetermined operating range; and • determining a first error if the operating quantity is outside the first operating range and within the respective second operating range for more than a predetermined period of time. Battery system with a battery assembly and a device according to claim 8. A computer program product containing program code stored on a computer-readable medium and which, when executed on a data processing device, performs the method of any one of claims 1 to 7.

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