DE102018210411A1 - Method for checking a temperature measurement value recorded in a battery system and battery system - Google Patents

Abstract

The invention relates to a method for checking a temperature measurement value (9) recorded in a battery system (1), the battery system (1) having at least one temperature sensor (4), comprising the following steps: a) Recording at least one temperature measurement value (9) by means of the at least one temperature sensor (4), b) detecting and / or receiving at least one status value (8), c) estimating at least one temperature estimate (10) by means of a reduced order model (11) on the basis of the detected and / or received at least one status value ( 8), the reduced order model (11) depicting a thermal behavior of the battery system (1) as a function of the at least one status value (8), d) checking the recorded at least one temperature measurement value (9) on the basis of the associated estimated at least one temperature estimate ( 10) and deriving verification information (12) from the verification result is, e) outputting or providing the verification information (12). The invention also relates to an associated battery system (1).

Description

The invention relates to a method for checking a temperature measurement value recorded in a battery system and to a battery system.

Battery systems are used in electric and hybrid vehicles. During driving as well as in the charging phase of these battery systems, heat is generated in the battery system by an electrical power loss in the current-carrying components. Since lithium-ion batteries may only be operated in a certain temperature range, the heat must be removed from the cells of the battery system. In order to check the functionality of the cooling system, for the application of the thermal management strategy and to determine a performance release of the cells, the respective existing temperatures must be determined both on the cell modules and in the cooling system. Temperature determination (e.g. on the shunt) is also becoming increasingly important in the shutdown unit (Battery Junction Box / Battery Module Control).

Temperature sensors are currently arranged on the cell modules, on the cooling system and on the current sensor (shunt) in order to record the respective temperatures. Due to the increasing requirements, the temperature measured values recorded with these temperature sensors often have to be checked for plausibility in order to identify faulty measured values or faulty sensors. In this way it can be prevented that due to a faulty temperature measured value, measures are taken by a control which unnecessarily impair the operation of the battery system. So far, a plausibility check of the temperature measured values has been done by a double, i.e. redundant design of temperature sensors, with temperature measurements of one temperature sensor being checked for plausibility by temperature measurements of the other temperature sensor.

If it is determined as part of this plausibility check that a temperature sensor is working incorrectly, a fault may be reported to the driver, e.g. by means of a yellow or red warning light or a corresponding message via the on-board computer. In the worst case, the battery system is restricted or even switched off, so that continued operation of the battery system or a vehicle is then only possible to a limited extent or not at all.

From the DE 10 2015 109 290 A1 a vehicle with a battery and a method are known in which temperature values within the battery are estimated using a reduced order model.

The invention is based on the object of providing a method for checking a temperature measurement value recorded in a battery system and a battery system in which a check of recorded temperature measurement values can be improved, in particular in a less complex and cost-saving manner.

The object is achieved according to the invention by a method with the features of claim 1 and a device with the features of claim 10. Advantageous embodiments of the invention result from the subclaims.

1. a) Erfassen mindestens eines Temperaturmesswertes mittels des mindestens einen T emperatu rsenso rs,
2. b) Erfassen und/oder Empfangen mindestens eines Zustandswertes,
3. c) Schätzen mindestens eines Temperaturschätzwertes mittels eines Modells reduzierter Ordnung auf Grundlage des erfassten und/oder empfangenen mindestens einen Zustandswertes, wobei das Modell reduzierter Ordnung ein thermisches Verhalten des Batteriesystems in Abhängigkeit des mindestens einen Zustandswertes abbildet,
4. d) Überprüfen des erfassten mindestens einen Temperaturmesswertes auf Grundlage des zugehörigen geschätzten mindestens einen Temperaturschätzwertes und Ableiten einer Überprüfungsinformation aus dem Überprüfungsergebnis,
5. e) Ausgeben oder Bereitstellen der Überprüfungsinformation.

In particular, a method for checking a temperature measurement value recorded in a battery system is provided, the battery system having at least one temperature sensor, comprising the following steps:

1. a) detecting at least one temperature measured value by means of the at least one temperature sensor,
2. b) detecting and / or receiving at least one status value,
3. c) estimating at least one temperature estimate using a reduced order model on the basis of the detected and / or received at least one status value, the reduced order model representing a thermal behavior of the battery system as a function of the at least one status value,
4. d) checking the recorded at least one measured temperature value on the basis of the associated estimated at least one estimated temperature value and deriving a check information from the check result,
5. e) Outputting or providing the verification information.

Furthermore, a battery system is created which is set up to carry out the method, comprising at least one temperature sensor for recording at least one temperature measured value, the battery system being set up in particular to record and / or receive at least one status value, at least one temperature estimate using a model estimate the reduced order on the basis of the detected and / or received at least one status value, the reduced order model representing a thermal behavior of the battery system as a function of the at least one status value, and the recorded at least one temperature measurement value on the basis of the associated estimated at least one To check the estimated temperature value and to derive and provide or provide verification information from the verification result.

In particular, it can be provided that the method is carried out in a control of the battery system, in particular in a battery management system (BMS). The controller is set up accordingly to carry out the method.

The invention therefore provides that at least one temperature measured value in the battery system is recorded by means of a temperature sensor. For example, a temperature sensor can be arranged on each module, each of which detects and provides a measured temperature value for the associated module. Furthermore, at least one status value is detected or received, for example this can be a current flowing current or a current delivered power of the battery system. On the basis of the at least one detected or received status value, at least one temperature estimate is estimated using a reduced order model, the reduced order model depicting a thermal behavior of the battery system as a function of the at least one status value. In the aforementioned example, an estimated temperature value for the respective operating location is then provided for each of the measured temperature values recorded on the modules. The at least one measured temperature value recorded is checked by means of the estimated at least one estimated temperature value, i.e. it can be checked for plausibility. For example, it can be checked whether a deviation between the measured temperature value and the associated estimated temperature value lies below a predetermined threshold value. If the deviation is below the threshold value, the temperature measurement value is assessed as plausible, whereas if the deviation is above the threshold value, the temperature measurement value is assessed as not plausible.

The method and the battery system have the advantage that, in particular, there is no need for a redundant sensor design in order to plausibility check of a temperature measurement value of a temperature sensor. The temperature values necessary for the plausibility check can be estimated using the reduced order model. As a result, it is sufficient, for example, to arrange only a single temperature sensor on each of the cells or modules of the battery system. The temperature measurement values recorded by the temperature sensors are then checked and checked for plausibility by the temperature estimated values respectively estimated by the method. As a result, the number of temperature sensors can be reduced and, as a result, costs and weight can be saved.

A further advantage is that, in addition to a plausibility check of the temperature measurement values of a temperature sensor, a fault in the temperature sensor can also be detected without an additional temperature sensor being necessary, since the temperature measurement value can be checked using the associated estimated temperature estimate.

Furthermore, if a temperature sensor malfunctions, substitute values for a temperature at the corresponding location in the battery system can be provided on the basis of the temperature estimate. These substitute values can then be used to enable the battery system to be operated without restriction and without being switched off.

The method and the associated battery system can thus be used both to replace existing temperature sensors and to additionally secure them.

In particular, it can be provided that the method and the battery system are used in a vehicle, in particular in a motor vehicle.

For the reduced order model (ROM), complex and computationally intensive multidimensional simulations are evaluated and then reduced in order. After the reduction, the reduced order model with very low computing power is already real-time capable, which is either not possible or too imprecise with conventional models. Various methods for creating the reduced order model are known to the person skilled in the art.

In particular, the at least one status value should already be recorded, calculated and / or provided by a device independently of the method, in particular as a signal in a vehicle or a battery control system (e.g. from a battery management system, BMS).

In particular, it can be provided that the at least one status value comprises at least one of the following: an electrical current determined at the shunt of the battery system, an electrical power determined at the shunt of the battery system, a fluid mass flow in a cooling device of the battery system, an inlet temperature of a fluid in a cooling device of the battery system, an outlet temperature of a fluid in a cooling device of the battery system, a temperature detected on a module of the battery system, an internal resistance of the battery system, one Internal resistance of a module and / or a cell of the battery system, an ambient temperature, a starting temperature of the battery system that is detected or provided before the battery system is used.

In one embodiment it is provided that at least one status value is provided by a control system of a vehicle. For example, an ambient temperature used as a status value can be detected by means of a temperature sensor of the vehicle and an associated temperature measurement value can be provided via a controller area network (CAN) bus of the vehicle.

In one embodiment it is provided that the reduced order model is generated on the basis of a higher-order simulation model that depicts the battery system, the at least one status value being used as a boundary condition in the simulation model.

In a further embodiment, it is provided that in order to generate the reduced order model, a transient behavior of the higher order simulation model is evaluated by means of a recursive approach. By using the recursive approach for transient models of reduced order, it is possible to map the total of highly dynamic load scenarios of the battery system. Ideally, only the status values such as e.g. a current and / or an ambient temperature of the battery system are used, which are already evaluated in a control of the battery system anyway.

In addition, the reduced order model can be used not only to record or estimate a temperature at a single position, but also a temperature field across the entire battery system. In this way, for example, areas of very high temperatures (hotspots) can also be located that cannot be detected by individual temperature sensors. In addition, other components (e.g. high-voltage components in a shutdown device or in controls) for which a temperature measurement would not be feasible or too cost-intensive can be thermally mapped in the model. It can be provided that a continuous diagnosis is carried out, e.g. by evaluating mean values and / or spreading an estimated temperature field.

In one embodiment it is provided that the estimation of the at least one temperature estimated value is carried out by means of the reduced order model in a battery control of the battery system (e.g. in a battery management system). As a result, temperature estimates can be estimated and processed directly in the battery control without the need for additional equipment.

In another embodiment it is provided that the estimation of the at least one temperature estimated value is carried out outside the battery system by means of the reduced order model. If the battery system is installed in a vehicle, for example, the estimation can be carried out in a control of the vehicle. As an alternative or in addition, the temperature estimate can also be estimated, for example, by a central server and made available to the battery system via a communication link.

In one embodiment it is provided that a battery controller controls the battery system on the basis of the checking information that is output or provided. In particular, on the basis of the checking information, the battery control system can, for example, make a more reliable decision as to whether the battery system may only be operated to a limited extent and whether the battery system must be switched off or not.

In a further embodiment it is provided that the at least one status value is or is selected such that it maps a complete space of operating conditions of the battery system which can have an effect on a temperature distribution within the battery system. As a result, an improved image of the thermal behavior of the battery system is achieved as a function of the at least one status value. In particular, this makes it possible to make more detailed statements about the temperatures present at various positions in the battery system, which is advantageous, for example, when predicting and / or localizing particularly hot areas in the battery system (hotspots).

In one embodiment it is provided that on the basis of the output or provided check information, status information of the at least one temperature sensor is generated and output. For example, on the basis of the checking information, a decision can be made as to whether there is a malfunction or a defect in the temperature sensor used for the detection, or whether it is working correctly. This is done, for example, by comparing the checking information with predefined criteria that must be adhered to in order for the temperature sensor to operate correctly. The verification information includes, for example, a discrepancy between a temperature measured value and an associated temperature estimate, it can be decided on the basis of the amount of the deviation whether the temperature sensor needs to be serviced or replaced. This result is then output using the status information. In this way, all the temperature sensors in the battery system can be continuously monitored for their functionality.

In a further embodiment it is provided that, based on the reduced order model, at least one further temperature estimate is additionally estimated and output for a position in the battery system at which no temperature sensor is arranged. In this way, for example, additional estimates can be provided for temperatures at positions at which no temperature sensors are usually arranged or where such an arrangement is not possible. Such positions can be located, for example, on a shutdown unit, within a cooling medium or on controls of the individual battery cells.

The individual embodiments of the method can be implemented accordingly in the device, the device then being set up to carry out the method. The advantages of corresponding embodiments of the device are the same as corresponding embodiments of the method.

• 1 eine schematische Darstellung einer Ausführungsform des Batteriesystems in einem Kraftfahrzeug;
• 2 ein schematisches Ablaufdiagramm für das Erstellen eines Modells reduzierter Ordnung.

The invention is explained in more detail below on the basis of preferred exemplary embodiments with reference to the figures. Here show:

• 1 a schematic representation of an embodiment of the battery system in a motor vehicle;
• 2 a schematic flow diagram for creating a model of reduced order.

In 1 is a schematic representation of an embodiment of the battery system 1 in a motor vehicle 50 shown. The battery system 1 spans several cells 2 which to modules 3 are summarized. For each of the cells 2 includes the battery system 1 a temperature sensor 4 which is a temperature at the respective cell 2 detected. Furthermore, a current, a power provided or consumed, and an internal resistance of each of the cells 2 and the modules 3 and the entire battery system 1 detected. The battery system 1 also includes battery control 5 which is the temperature readings of the temperature sensors 4 and the other recorded measured values are supplied. More measurements 6 , such as an ambient temperature, can be controlled by the battery 5 via a CAN bus 7 of the motor vehicle 50 be queried. The individual measured values are subsequently called state values 8th used.

It can be provided that a temperature on a cooling system (not shown) of the battery system 1 is detected, for example at the inlet and / or outlet of a coolant in a cooling circuit of the cooling system.

By means of the temperature sensors 4 on the cells 2 is a temperature reading in each case 9 detected.

The battery control 5 is set up to measure the current, the power supplied or consumed and the internal resistance of the cells 2 , the modules 3 and the entire battery system 1 as well as the ambient temperature as state values 8th to detect and / or receive and for each of the positions at which one of the temperature sensors 4 are arranged, an estimated temperature value 10 using a reduced order model 11 based on the detected and / or received status values 8th appreciate. The reduced order model 11 forms a thermal behavior of the battery system 1 depending on the status values 8th from. The battery control also checks 5 the measured temperature values 9 based on the associated estimated temperature estimates 10 , derives verification information from the verification result 12 and outputs or issues them, for example via the CAN bus 7 , ready for further evaluation and signaling.

The battery control 5 can read the individual temperature readings 9 Check the plausibility of the check information, for example by checking whether the respective temperature measurement values 9 and the associated temperature estimates 10 agree with each other or whether there is a deviation between them within a predetermined tolerance range.

It can also be provided that the battery control 5 the battery system 1 based on the review information provided or provided 12 controls, for example by performing individual modules 3 is regulated.

It can also be provided that the battery control 5 based on the review information provided or provided 12 a status information of the temperature sensors 4 generates and outputs. For example, battery control 5 for each of the temperature sensors 4 provide status information that provides information on the respective functionality of the temperature sensor 4 includes, for example in the form of a message "Sensor OK", "Sensor faulty" or "Sensor defective" displayed on a display etc. A generated status information can also include maintenance requests and / or maintenance instructions.

It can also be provided that the battery control 5 based on the reduced order model, at least one additional temperature estimate for a position in the battery system 1 on which there is no temperature sensor 4 is arranged, estimates and outputs. For example, in this way a temperature of a shutdown unit (not shown) of the battery system 1 can be monitored without an additional temperature sensor.

Parts of the battery system 1 , especially battery control 5 , can be designed individually or in combination as a combination of hardware and software, for example as program code that is executed on a microcontroller or microprocessor.

In 2 a schematic flow diagram for creating a reduced order model is shown. In particular, the model is created during an offline phase 100 , which means that the model is not created in the battery system itself. In a first step 101 A Computer Aided Design (CAD) model of the battery system is created, which describes the individual components, the materials and their arrangement in the battery system in detail. Based on the CAD model will be in step 102 several simulations were carried out, for example using a computational fluid dynamics (CFD) simulation for the battery system created from the CAD model. As boundary conditions 103 The different simulations are different combinations of state values 8th used. The simulation results 104 depict the estimated temperature values that correspond to the respective combination of state values 8th belong.

In this way there are now various combinations of transient courses of the state values 8th simulated and curves of resulting temperature fields within the battery system saved as results. From the resulting combinations of state values 8th and associated simulation results for the temperatures within the battery system, the model of reduced order in the step 105 trained or reduced the simulation model. This includes in particular the teaching of time-dependent relationships between the state values 8th and the resulting temperatures in the battery system.

Is the reduced order model after the offline phase 100 fully upgraded, it can be in a subsequent online / onboard phase 200 be used on a controller of a vehicle or a controller of the battery system or are made available to the vehicle or the battery system via online services. Instead of the transient courses from the offline phase 100 serve the currently recorded and / or received status values 8th from the battery system or from the vehicle as input parameters 201 of the trained model of reduced order 11 , that about the recorded state values 8th real-time temperature estimates 9 to a current one through the state values 8th estimates the operating point of the battery system described. Recorded temperature readings 10 are then calculated based on the associated estimated temperature estimates 9 checked and a check information derived from this, which is then output and provided.

LIST OF REFERENCE NUMBERS

1

battery system

2

cell

3

module

4

temperature sensor

5

battery control

6

reading

7

CAN bus

8th

state value

9

Temperature reading

10

Temperature estimate

11

Reduced order model

12

Check information

50

motor vehicle

100

Offline phase

101

step

102

step

103

boundary condition

104

simulation results

105

step

200

Online / onboard phase

201

input parameters

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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.

Patent literature cited

• DE 102015109290 A1 [0005]

Claims (10)

Method for checking a temperature measurement value (9) recorded in a battery system (1), the battery system (1) having at least one temperature sensor (4), comprising the following steps: a) detecting at least one temperature measurement value (9) by means of the at least one temperature sensor (4), b) detecting and / or receiving at least one status value (8), c) Estimating at least one temperature estimate (10) by means of a reduced order model (11) on the basis of the detected and / or received at least one status value (8), the reduced order model (11) depending on the thermal behavior of the battery system (1) which depicts at least one status value (8), d) checking the recorded at least one temperature measured value (9) on the basis of the associated estimated at least one temperature estimated value (10) and deriving a check information item (12) from the check result, e) Outputting or providing the verification information (12). Procedure according to Claim 1 , characterized in that the reduced order model (11) is generated on the basis of a higher order simulation model depicting the battery system (1), the at least one status value (8) being used as a boundary condition (103) in the simulation model. Procedure according to Claim 2 , characterized in that in order to generate the reduced order model (11), a transient behavior of the higher order simulation model is evaluated by means of a recursive approach. Method according to one of the preceding claims, characterized in that the estimation of the at least one temperature estimate (10) by means of the reduced order model (11) is carried out in a battery control (5) of the battery system (1). Procedure according to one of the Claims 1 to 3 , characterized in that the estimation of the at least one temperature estimate (10) by means of the reduced order model (11) is carried out outside the battery system (1). Method according to one of the preceding claims, characterized in that a battery controller (5) controls the battery system (1) on the basis of the checking information (12) output or provided. Method according to one of the preceding claims, characterized in that the at least one status value (8) is or is selected such that it maps a complete range of operating states of the battery system (1) which have an effect on a temperature distribution within the battery system (1) can. Method according to one of the preceding claims, characterized in that status information of the at least one temperature sensor (4) is generated and output on the basis of the output or provided check information (12). Method according to one of the preceding claims, characterized in that, based on the reduced order model (11), at least one further temperature estimate is additionally estimated and output for a position in the battery system (1) at which no temperature sensor (4) is arranged. Battery system (1) comprising: at least one temperature sensor (4) for recording at least one temperature measurement value (9), The battery system (1) is set up to detect and / or receive at least one status value (8), to estimate at least one temperature estimate (10) by means of a reduced order model (11) on the basis of the detected and / or received at least one state value (8), the reduced order model (11) determining a thermal behavior of the battery system (1) as a function of the depicts at least one status value (8), and to check the recorded at least one temperature measurement value (9) on the basis of the associated estimated at least one temperature estimate value (10) and to derive and output or provide verification information (12) from the verification result.

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