DE102022133914A1 - Control device for a motor vehicle and method for determining a temperature in the interior of a battery cell - Google Patents

Abstract

The invention relates to a method for determining a first temperature (T1; T1a, T1b, T1c, T1c', T1d) in an interior (52) of a battery cell (16) of a battery arrangement (12) which comprises a battery module (24) with the battery cell (16) and a cooling device (28, 30) for cooling the battery module (24), wherein a second temperature (T2) is detected by means of a temperature sensor (20) outside the battery cell (16). In this case, a temperature model (M) of the battery arrangement (12) is provided and at least one current, time-varying state variable (Z) of a thermal component (10, 16, 28, 30) or of a thermal medium (40; 22) influencing a thermal behavior of the battery arrangement (12) is detected and the first temperature (T1; T1a, T1b, T1c, T1c', T1d) is determined by the control device (14) by means of the temperature model (M) and depending on the second temperature (T2) as a first input variable (E2) for the temperature model (M) and depending on the current state variable (Z) as a second input variable (E1) for the temperature model (M).

Description

The invention relates to a method for determining a first temperature in the interior of a battery cell of a battery arrangement, wherein the battery arrangement comprises a battery module with the battery cell and a cooling device for cooling the battery module. A second temperature is detected by means of at least one temperature sensor, which is arranged at a specific point on the battery module outside the battery cell, and the first temperature is determined by a control device depending on the second temperature. Furthermore, the invention also relates to a control device for a motor vehicle.

In current high-voltage batteries, temperatures and electrical power are monitored in order to derive a temperature control requirement. The aim is to keep the battery in an optimal temperature range so that maximum power is available or the battery can be charged in an energy-efficient manner. For example, the battery has a lower resistance at higher temperatures. Operating the battery in an optimal temperature range can also minimize the aging of the battery cells. For all of these situations, it is therefore desirable to know the temperature of a battery cell as precisely as possible. The measured temperatures of the cell modules are usually considered and the temperature control requirement is derived from this. The temperatures of the cell modules are typically measured using temperature sensors outside the battery cells. These are often distributed across a battery module with several cells, although a temperature sensor is not necessarily arranged on each cell. The positioning of the temperature measuring points within a high-voltage battery therefore only allows an evaluation of local temperatures, which only provides approximate information about the actual temperatures in the cell winding of a battery cell, the active material of a battery cell or the cell flag of a battery cell, which are often the limiting variables. In other words, the temperature inside a battery cell can only be estimated relatively imprecisely. In addition, the temperatures measured outside a battery cell are greatly distorted by the environment and environmental influences, for example by heat sinks arranged on the battery cells or hot busbars near the temperature sensors. Due to the lack of more precise temperature values from inside the cell, the current performance of the cell can only be determined imprecisely and the temperature control cannot be carried out in a targeted manner.

The EN 10 2017 220 547 A1 describes a method for determining the temperature of an electric machine by means of a temperature model of the electric machine, wherein a temperature of an electrical supply line of the electric machine for conducting an electrical current to operate the electric machine is used as the starting temperature for the temperature model.

However, the temperature of a battery cell, especially inside a battery cell, is not determined.

The EN 10 2017 209 182 A1 describes a method for determining an operating temperature of a battery cell, in which a value of a measured variable is recorded externally to the battery cell to determine an external temperature of the battery cell, an internal temperature of the battery cell is determined by recording an electrical impedance of the battery cell, and a value of the operating temperature of the battery cell is determined from the external and internal temperatures. In addition, the recorded value of the measured variable can be used in a temperature model for the battery cell to determine the external temperature of the battery cell.

The object of the present invention is to provide a method and a control device which enable a temperature inside a battery cell of a battery arrangement to be determined as accurately as possible.

This object is achieved by a method and a control device with the features according to the respective independent patent claims. Advantageous embodiments of the invention are the subject of the dependent patent claims, the description and the figures.

In a method according to the invention for determining a first temperature in the interior of at least one battery cell of a battery arrangement, which comprises a battery module with the at least one battery cell and a cooling device for cooling the battery module, a second temperature is detected by means of at least one temperature sensor, which is arranged at a specific location on the battery module outside the at least one battery cell, and the first temperature is determined by a control device depending on the second temperature. A temperature model of the battery arrangement is provided, wherein at least one current, time-varying state variable of a thermal component or a thermal medium, which influences a thermal behavior of the battery arrangement, is detected and determined by the control device using the temperature model and depending on from the second temperature as a first input variable for the temperature model and depending on the current state variable as a second input variable for the temperature model, the first temperature is determined.

The invention is based on the knowledge that the temperature of a battery cell is also influenced by components or media that are in thermal contact, in particular directly or indirectly, with the battery cell. In order to be able to determine the temperature inside the battery cell as accurately as possible, this temperature being referred to here as the first temperature, it is therefore very advantageous to provide not only a temperature model for the battery cell itself, but also a temperature model of the battery arrangement of which the battery cell is a part. In other words, the temperature model preferably models at least one component of the battery arrangement that is different from the battery cell in addition to the at least one battery cell. This allows a much more precise modeling of the thermal conditions in the immediate vicinity of the battery cell, and in particular also inside the battery cell itself. In addition, the invention is based on the knowledge that the battery cell can also be surrounded by components or media, such as the cooling device and the cooling medium conveyed by it, which can change their thermal behavior over time and can therefore also influence the thermal behavior of the battery arrangement in a time-variable manner. It is therefore very advantageous to supply at least one such state variable as an input variable for such a temperature model, in particular in addition to the second temperature detected by the temperature sensor. This allows a much more precise modeling of the temperature conditions inside the battery cell and therefore also a much more precise determination of the first temperature inside the battery cell.

The battery cell can be a lithium-ion cell, for example. This can be part of a battery module that not only has the battery cell as the only battery cell, but for example several battery cells. The battery arrangement can also comprise several such battery modules, each with several battery cells. The battery cell can have a cell housing and an electrode layer arrangement arranged in the cell housing in the form of a cell coil, i.e. wound electrode layers that are separated from one another by separator layers, or in the form of an electrode stack, i.e. stacked electrode layers that are separated from one another by separator layers. In addition, the cell can comprise two cell poles in the form of two cell terminals. The electrode layer arrangement is also electrically connected to the terminals of the cell via at least two conductor elements, one for a positive cell potential and one for a negative cell potential. In addition, the battery cell can be designed as a pouch cell, prismatic battery cell or round cell. The battery arrangement can be, for example, a high-voltage battery for a motor vehicle, or an arrangement which comprises such a high-voltage battery. In addition to the cooling device for cooling the battery module, the battery arrangement can also have numerous other components. For example, in addition to the at least one battery cell, the battery module can also have a module housing in which the battery cell is arranged. In addition, the battery arrangement can comprise an overall battery housing in which the battery module or optionally also several battery modules are arranged. In addition, there can be a thermal interface material between the battery module and the battery housing, for example a thermally conductive paste or thermally conductive compound in a hardened state, which is also referred to as a gap filler. In addition, a component of the battery housing, for example the base and/or cover of the battery housing, can also simultaneously provide the cooling device for cooling the battery module. The cooling device can therefore be designed as a cooling plate which comprises cooling channels through which a coolant or cooling medium, preferably a cooling liquid, can flow. This coolant flows through these cooling channels when the cooling device is in operation. The cooling device can be integrated into a cooling circuit accordingly. At least one pump can be provided to convey the coolant through the cooling circuit, in particular to circulate this coolant in the cooling circuit. With respect to a first direction, which preferably points in the direction of a vertical axis of a motor vehicle in which the battery arrangement is used, an underrun protection device is arranged below the battery housing, for example.

This means that the at least one battery cell is directly or indirectly surrounded by numerous other components of the battery arrangement, which are typically made of different materials and accordingly also have different thermal properties. All of these components of the battery arrangement can advantageously be taken into account in the temperature model of the battery arrangement by means of suitable parameterization, as will be explained in more detail later. This makes it possible to provide an all-encompassing temperature model which depicts the thermal conditions of the battery arrangement particularly precisely. The use of this temperature model therefore advantageously enables a particularly precise determination of the first temperature inside the battery cell. The at least one temperature sensor, which is arranged at a specific point on the battery module outside the battery cell, can be provided, for example, by a temperature-dependent resistor. The temperature sensor is preferably arranged on an outside of the battery cell or the outside of another battery cell of the battery module, e.g. on the outside of the cell housing. The measurement signal of the temperature sensor can be transmitted to a higher-level control unit or a microcontroller or the like. Such a control unit or microcontroller can be provided by the control device or can be understood as part of the control device or at least be communicatively connected to it. In addition, several temperature sensors can also be provided in the battery module, especially if it comprises several battery cells. These can be arranged distributed over the battery cells of the battery module, in particular on the outside of the battery cells. The at least one temperature sensor is therefore particularly preferably arranged on an outside of the battery cell or the cell housing, in particular on a side of the battery cell that is not arranged on the cooling device or is connected to the cooling device via the gap filler. For example, the at least one temperature sensor can be arranged on a side of the battery cell on which at least one of the two cell poles of the battery cell is also arranged. The two cell poles of the battery cell can also be arranged on the same side of the battery cell, or on different sides of the battery cell, for example on opposite sides of the battery cell.

If the battery module comprises several battery cells and several temperature sensors, a temperature sensor does not necessarily have to be arranged on each of the battery cells. The battery module can also comprise battery cells on which no temperature sensors are arranged. For example, a temperature sensor can be arranged on every second battery cell or every third battery cell or every fourth battery cell and so on. This is not a disadvantage, especially in combination with the temperature model, since the possibility of modeling the temperature conditions in the battery module and overall in the entire battery arrangement makes it possible to save on additional temperature sensors. In principle, it is also conceivable to connect just a single temperature sensor for a battery module to several battery cells. However, especially with large battery modules, the accuracy can be increased by providing additional temperature sensors.

The temperature model mathematically maps the thermal conditions in the battery arrangement based on the physical relationships. The temperature model can be stored in a memory of the control device. Furthermore, the control device can be designed to repeatedly determine the first temperature inside the battery cell. In other words, the method described can be carried out repeatedly in respective successive time steps. This makes it possible to provide continuous temperature monitoring of the battery cell. In the course of this, the input variables of the temperature model can also be recorded repeatedly. However, different input variables for the temperature model do not have to be recorded with the same frequency.

In a very advantageous embodiment of the invention, the at least one state variable relates to the at least one battery cell and/or at least one other battery cell of the battery arrangement. Depending on the mode of operation of the battery cell, the battery cell itself also produces more or less heat, which in turn leads to the heating of the battery cell itself. In addition, the at least one battery cell is strongly influenced by its immediate surroundings, and therefore also by the heat of any neighboring cells. If the at least one battery cell is in a cell stack with several battery cells, and the cell is positioned, for example, in an edge area of the cell stack, the cell is more strongly influenced by the temperature in the vicinity of the cell stack, and if the cell is located between other cells in the cell stack, for example relatively far in the middle of the cell stack, the cell is very strongly influenced by the heat of the other cells, in particular the neighboring cells. It is therefore very advantageous to take into account a state variable that relates to the state of the battery cell itself and/or at least one other battery cell as an input variable for the temperature model. It is precisely the operating state of the battery cell and/or the further battery cell that significantly influences the thermal behavior of the battery arrangement in general and, in particular, the temperature that develops inside the battery cell. It is therefore very advantageous to take into account a state variable of the battery cell itself and/or the further battery cell. Furthermore, this embodiment of the invention is based on the realization that it is not necessary to measure the temperature inside the battery cell itself in order to obtain information about the current thermal behavior of the battery cell itself. Numerous other, in particular electrical, variables of the battery cell are also suitable here in order to characterize the current operating state of the battery cell, and from this in turn to the current thermal state of the battery cell and/or the other battery cell.

Therefore, it is a further very advantageous embodiment of the invention if the at least one state variable relating to the battery cell and/or the further battery cell represents at least one of the following: a power loss currently generated by the battery cell and/or the further battery cell, a current cell current of the at least one battery cell and/or the further battery cell, a current cell voltage of the at least one battery cell and/or the further battery cell and a current state of charge of the at least one battery cell and/or the further battery cell. In particular, it is very advantageous to take into account the power loss currently generated by the battery cell and/or the further battery cell when determining the first temperature inside the battery cell. This can be included directly in the temperature model as an input variable or, on the other hand, can be determined from other variables, such as the cell current, the cell voltage and/or the state of charge of the battery cell, if necessary with the aid of a characteristic curve or a characteristic curve field. The power loss of the battery cell corresponds with very high accuracy to the heat generated by the battery cell itself during operation. If no battery current flows through the battery cell, i.e. neither a load current to supply a consumer connected to the cell nor a charging current to charge the battery cell, then no heat is actively generated by the battery cell itself. In all other cases in which a load current is provided by the battery cell or the battery cell is charged by a charging current, a certain power loss is generated due to the internal resistance of the battery cell, which is almost completely converted into heat. It is therefore very advantageous to take into account the power loss currently generated by the battery cell in order to accurately describe the temperature conditions of the battery cell and the battery arrangement as a whole. The same applies to optional additional cells. As already mentioned, the power loss depends on the current cell current of the battery cell. It is therefore very advantageous, for example to determine the power loss or as an input variable for the temperature model, to record the current cell current of the at least one battery cell and/or the other battery cell and to determine the first temperature based on this. The current cell voltage of the at least one battery cell and/or the other battery cell also influences the power loss. The current cell voltage, and in particular the resting voltage of the battery cell, in turn depend on the state of charge of the battery cell.

These variables can also be related using a characteristic field. This makes it easy to determine the power loss currently generated by the battery cell based on a few measured variables, which are available anyway because they are also recorded and monitored for other purposes, such as cell voltage and cell current, and to determine the first temperature based on this, in particular with the help of the temperature model.

Thus, the at least one state variable can represent a power loss currently generated by the battery cell and/or the further battery cell or, depending on the at least one state variable, the power loss currently generated by the battery cell and/or the further battery cell can be determined or is determined.

In a further advantageous embodiment of the invention, the at least one state variable relates to the cooling device and represents at least one of the following state variables: a current cooling or heating power provided by the cooling device for controlling the temperature of the battery module, a current third temperature of a coolant of the cooling device, wherein the third temperature can be understood, for example, as an average temperature, a current fourth temperature of a coolant of the cooling device at an inlet of the cooling device, a current fifth temperature of a coolant of the cooling device at an outlet of the cooling device, and a current mass flow of a coolant flowing through the cooling device.

The cooling device and its current temperature state also have a significant influence on the battery arrangement when the cooling device is in operation. It is therefore very advantageous to also take parameters of the cooling device into account when determining the first temperature inside the battery cell. If, for example, the cooling device is currently providing a very high cooling capacity, a very large part of the heat generated in the battery cell itself via its power loss can be dissipated quickly and efficiently and thus does not contribute significantly to the heating of the battery cell itself. If the cooling capacity currently provided by the cooling device is very low, the battery cell heats up significantly more due to the power loss it generates, all other conditions being equal. This means that the first temperature inside the battery cell can be determined much more precisely if information about the current state of the cooling device is also taken into account when determining the first temperature. In this case, it is particularly advantageous to take the current cooling capacity provided by the cooling device into account. The cooling and/or heating performance can be taken into account or recorded or determined. This can in turn be determined from other variables, in particular measured variables, for example the current temperature of the coolant and the mass flow of the coolant currently flowing through the cooling device. If the current temperature of the coolant, for example the average temperature of the coolant, which can be provided by the third temperature, is known, the influence of this coolant on the battery cell is also known and can therefore advantageously be taken into account according to the temperature model in order to determine the first temperature. An even more precise determination of the first temperature is also possible if not only the average coolant temperature is taken into account, for example, but also a fourth temperature at an inlet of the cooling device and a fifth temperature at an outlet of the cooling device. By forming the temperature difference, for example, in particular additionally knowing the current mass flow, it can be determined how much heat per unit of time is absorbed by the cells from the cooling device, in particular according to: $$\dot{\text{Q}}=\dot{\text{m}}\text{c}\Delta \text{T}.$$

Here, Q denotes the time derivative of the amount of heat Q absorbed or released by the cooling device, m is the mass flow of the coolant, c is the specific heat capacity of the coolant and ΔT is the difference between the fourth and fifth temperatures.

In the same way, it can be used to determine not only how much heat is absorbed by the cooling device when the battery cell is cooled, but also how much heat is given off to the battery cell when the battery cell is heated via the cooling device. The temperatures of the coolant, in particular the average temperature and/or the temperatures at the inlet and outlet of the cooling device, can also be measured using other temperature sensors. Furthermore, if the coolant temperature is measured at the inlet and outlet, it can be assumed that an approximately linear temperature gradient results, for example, across the battery cells or along the coolant path. This can be used, for example, to determine which temperature prevails at the location of the battery cell in question and which coolant temperature gradient results accordingly across the battery cell in question. This is particularly advantageous if the cooling device cannot provide uniform cooling of all battery cells and, for example, some battery cells are cooled more than others, for example due to their position, which may be closer to the inlet of the cooling device or to the outlet of the cooling device, wherein the coolant is typically colder at the inlet of the cooling device than at the outlet, in particular if the cooling device is intended to provide cooling power for cooling the cells. In a homogeneous cooling concept, according to which the cooling device can provide relatively homogeneous cooling of all cells, the calculation of the amount of heat given off to or absorbed by a cell to the cooling device can be simplified by assuming that the same amount of heat is given off to the cooling device or absorbed by the cooling device by each cell of the battery module.

In this case, no segmentation of the coolant temperature is required as explained above. Segmentation is understood to mean the segment-by-segment consideration of the initial and final temperature of the coolant at the beginning of the relevant segment and at the exit of the corresponding segment, whereby a respective segment can be assigned to a respective battery cell of the battery module.

In a further very advantageous embodiment of the invention, the at least one state variable represents a current ambient temperature. This is based on the knowledge that the current ambient temperature, in particular of the battery arrangement, and above all of the entire motor vehicle, also influences the current first temperature inside the battery cell. In particular, the ambient temperature also affects the efficiency of the cooling device. It is therefore particularly advantageous to also take the ambient temperature into account when determining the first temperature of the battery cell.

In a further advantageous embodiment of the invention, the at least one state variable represents a current speed of the motor vehicle comprising the battery arrangement. This in turn also affects the thermal behavior of the battery arrangement itself. This is particularly dependent on the cooling effect of the airstream. This environmental influence can therefore also be taken into account when determining the first temperature, which in turn allows the first temperature of the battery cell to be determined even more precisely.

Overall, several “thermally active” factors influencing the temperature, especially the internal temperature, of the battery cell can be taken into account, namely the thermal behavior the battery cell itself, the thermal behavior of the cooling device and the thermal behavior of the environment. All of these influencing factors, which can in particular show a thermal behavior that changes over time and act as a heat source or heat sink depending on the state, can thus advantageously be taken into account when determining the first temperature within the framework of the temperature model. This advantageously allows a comprehensive description of the thermal conditions of the battery arrangement and a particularly precise determination of the first temperature.

However, the temperature inside the battery cell is not only influenced exclusively by such thermally active components and media, but also by thermally passive components of the battery arrangement, which, due to their respective heat capacities, enable a reversible heat exchange with their respective environment and can thus absorb and release heat.

Accordingly, it is a further very advantageous embodiment of the invention if the battery arrangement has at least one component, wherein at least one parameter relating to the at least one component is stored in the temperature model as a model parameter, in particular wherein the parameter represents a specific heat capacity of the component, and/or represents a mass of the component, and/or represents a thermal resistance and/or a thermal conductivity of the component, wherein the first temperature is determined as a function of the model parameter. These passive components can therefore advantageously be thermally characterized by the model parameters mentioned. The thermal resistance is indirectly proportional to the thermal conductivity of the component, so that knowledge of one of these two quantities is sufficient. These quantities can therefore describe how much heat can be absorbed, released again and how quickly the corresponding component can be passed on in which situation. Both the thermostat and the thermodynamics of this component can thus be described comprehensively. This in turn enables an even more precise description and determination of the first temperature. The component can generally represent one of the components of the battery arrangement that have already been described above. In particular, each component of the battery arrangement can be described by such parameters in the temperature model. The components can therefore be parts of a module housing of the battery module, a thermal interface material, an overall battery housing, an underrun protection, also air pressures between these components, other body components of the motor vehicle on which the battery arrangement is arranged, components of the cooling device or cooling devices, for example the cooling plates and so on. If several components show a similar thermal behavior, several components can also be combined to form an overall component and described, for example, by an equal heat capacity or average specific heat capacity, total mass and average thermal conductivity. This simplifies the temperature model. Whether components have a similar thermal behavior can be determined experimentally, for example. This advantageously means that all possible passive components can also be taken into account in the temperature model. Passive components are in particular those that do not change their thermal behavior over time. This means that the corresponding model parameters, i.e. the parameters that characterize these components thermally, can be stored as fixed parameters in the temperature model. The temperature model is thus optimally adapted to a given battery arrangement and its components.

In a further advantageous embodiment of the invention, the battery arrangement has at least one component, which can in particular represent one of the components already mentioned above, wherein a current sixth temperature of the component and/or a current heat flow associated with the component is determined as a function of a seventh initial temperature of the component, which is determined as the ambient temperature and/or the second temperature in a predetermined operating situation of the battery arrangement, in particular immediately after a predetermined long inactive phase of the battery arrangement. On the one hand, it is particularly advantageous to also determine a temperature and/or an associated heat flow for this component. This makes it possible to describe the thermal behavior of this component and its influence on the battery cell, in particular again within the framework of the temperature model. This advantageously makes it possible to determine not only the current first temperature inside the battery cell within the framework of the temperature model, but also in principle any temperature of any other component of the battery arrangement. For this purpose, only one temperature is required to initialize the temperature model. In other words, at least one temperature should be known at a specific point in time within the battery arrangement. It is particularly advantageous to have a seventh initial temperature of the component in a specific operating phase of the battery arrangement, namely a passive or inactive active phase of the battery arrangement, after the motor vehicle has been stationary for a sufficiently long time. In other words, if a motor vehicle has been stationary for a sufficiently long time without the battery arrangement being in operation, i.e. without a charging process having taken place to charge the battery arrangement, all components of the battery arrangement are generally at the same temperature, namely approximately the ambient temperature, which then also represents the second temperature that can be detected by the temperature sensor. In other words, both the ambient temperature, which can be detected by a separate temperature sensor for detecting the ambient temperature, and/or the second temperature can be used as the starting temperature for the components. These temperatures, i.e. either the ambient temperature or additionally or alternatively the second temperature, can then be used as the starting temperature for any component of the battery arrangement, including the battery cell. Based on this starting temperature, the temperature model can then be used to model the temporal development of the temperatures of the respective components, including the battery cell, when the battery arrangement is then put into operation. Based on this, the heat flows associated with the respective components can then be determined, which in turn lead to a change in the temperature of the respective components, including the battery cell. This means that the temperature inside the battery cell as well as the temperature development of every other component in the battery arrangement can be determined very precisely over time.

As a result, it is generally not only possible to determine a single temperature, i.e. a single temperature value, as the first temperature inside the battery cell, but also several. Therefore, a further very advantageous embodiment of the invention is when several first temperatures are determined for the battery cell, each of which relates to different areas within the battery cell. For example, a first temperature can be determined for an underside of the battery cell, in particular with respect to the first direction defined above, a temperature for a central area within the battery cell and a first temperature for an upper area of the first battery cell. This is based on the knowledge that a temperature distribution of the temperature within a battery cell is generally not homogeneous when the battery cell is in operation. However, it can be assumed that the temperature conditions of the various areas within the battery cell are approximately constant. This advantageously makes it possible to divide the total amount of heat contributing to or causing the heating of the battery cell inside between the individual areas using a factor. This allows the first temperature to be determined individually for each of these areas within the battery cell, in particular as already described for the first temperature.

As already mentioned, the first direction defined above preferably points in the direction of the vehicle's vertical axis in relation to a preferred intended installation position in a motor vehicle. In principle, however, any other installation positions are also conceivable. Thus, lateral cooling of the at least one battery cell can also be provided, e.g. by a cooling plate arranged on the side of the battery cell. In particular, the cooling device can have one or more cooling plates or other cooling elements which, with respect to a specific installation position in the motor vehicle, are arranged above the at least one battery cell and/or below the at least one battery cell and/or on one or two sides of the at least one battery cell, which are different from a top and bottom of the battery cell. In principle, all-round cooling of the battery cell by the cooling device is also conceivable. In addition, the battery arrangement, in particular the cooling device, can also be designed such that the coolant directly contacts the battery cell on one side or on several sides or on all sides of the battery cell. At least part of a wall delimiting the coolant channel of the cooling device is then provided in this case by one or more or all sides of the cell housing of the battery cell itself. This allows the cooling or heating caused by the coolant to act directly on the cell and the resulting heat flow between the battery cell and the cooling device can also be modeled more easily.

Since, based on the temperature model for the battery arrangement as described above, not only the temperature of the battery cell itself, in particular inside the battery cell, can be determined, but also in principle for every other component outside the battery cell, it is advantageously possible to carry out a plausibility check, for example of the second temperature detected by means of the temperature sensor, based on the temperature model and the temperatures of the other components determined in this context. In this case, it represents a further very advantageous embodiment of the invention if the control device compares the determined first temperature and/or the measured second temperature with a reference temperature range. and generates a signal in the event of a predetermined deviation. The reference temperature range can, for example, be determined on the basis of the temperature model as described above. In other words, the control device can, for example, determine a corresponding temperature at the point at which the temperature sensor is positioned and compare this with the temperature measured by the temperature sensor. This makes it easier to detect “outliers”, temporary incorrect measurements by the temperature sensor, or it can also be determined if the temperature sensor is fundamentally unfavorably positioned, for example in too close proximity to a power rail that generates a lot of heat, so that the temperature measured by the temperature sensor is greatly distorted. Such a plausibility check can also be used to detect any drift in the values over time. Accordingly, it is advantageous to provide a corresponding monitoring function that checks the plausibility of the temperature model and temperature sensor values and, if necessary, marks them as invalid. In the case of high loads, for example during dynamic driving of the motor vehicle or a high power demand from the battery module or the battery arrangement, a high cooling capacity and so on, it is advantageous to allow a larger deviation over time and to classify it as still plausible than, for example, with a constant charging current or constant or low cooling capacity or during parking or generally in relatively homogeneous load conditions of the cell. The predetermined deviation can also be selected depending on the current operating situation of the battery cell or the battery arrangement. If a predetermined large deviation occurs or is exceeded, the control device can generate a corresponding signal. This can fulfill or trigger a variety of functions. For example, it can generate an entry in an error memory, issue a warning to a higher-level control unit, lead to increased control of the cooling device and so on.

Overall, the use of the described temperature model enables the provision of more precise information about the temperature in the cell and thus an improved determination of the state of the cell, in particular its current state of charge (SOC), its internal resistance, its capacity, and thus improves the performance of the cell with an impact on charging times, driving performance and cell aging. The range can be increased by optimizing the control of the cooling or heating of the battery.

For use cases or application situations that may arise during the method and which are not explicitly described here, it may be provided that, in accordance with the method, an error message and/or a request to enter user feedback is issued and/or a default setting and/or a predetermined initial state is set.

Furthermore, the invention also relates to a control device for a motor vehicle, which is designed to carry out a method according to the invention or one of its embodiments.

In addition, a motor vehicle with such a control device should also be considered to be part of the invention. The motor vehicle can also include the battery arrangement.

The control device can have a data processing device or a processor device that is set up to carry out an embodiment of the method according to the invention. For this purpose, the processor device can have at least one microprocessor and/or at least one microcontroller and/or at least one FPGA (Field Programmable Gate Array) and/or at least one DSP (Digital Signal Processor). Furthermore, the processor device can have program code that is set up to carry out the embodiment of the method according to the invention when executed by the processor device. The program code can be stored in a data memory of the processor device. A processor circuit of the processor device can, for example, have at least one circuit board and/or at least one SoC (System on Chip).

The invention also includes further developments of the control device according to the invention, which have features as have already been described in connection with the further developments of the method according to the invention. For this reason, the corresponding further developments of the control device according to the invention are not described again here.

The motor vehicle according to the invention is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus or motorcycle.

As a further solution, the invention also comprises a computer-readable storage medium comprising instructions which, when executed by a computer or a computer network, cause the computer or computer network to carry out an embodiment of the method according to the invention. The storage medium can, for example, be at least partially designed as a non-volatile data storage (e.g. as a flash memory and/or as an SSD - solid state drive) and/or at least partially as a volatile data storage (e.g. as a RAM - random access memory). The storage medium can also be operated, for example, as a so-called app store server on the Internet. The computer or computer network can provide a processor circuit with at least one microprocessor. The commands can be provided as binary code or assembler and/or as source code of a programming language (e.g. C).

The invention also includes combinations of the features of the described embodiments. The invention therefore also includes implementations that each have a combination of the features of several of the described embodiments, provided that the embodiments have not been described as mutually exclusive.

• 1 eine schematische Darstellung eines Kraftfahrzeugs mit einer Batterieanordnung und einer Steuereinrichtung zum Ermitteln einer Temperatur einer Batteriezelle gemäß einem Ausführungsbeispiel der Erfindung; und
• 2 eine schematische Darstellung der Batterieanordnung aus 1 gemäß einem Ausführungsbeispiel der Erfindung.

Exemplary embodiments of the invention are described below.

• 1 a schematic representation of a motor vehicle with a battery arrangement and a control device for determining a temperature of a battery cell according to an embodiment of the invention; and
• 2 a schematic representation of the battery arrangement 1 according to an embodiment of the invention.

The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the components of the embodiments described each represent individual features of the invention that are to be considered independently of one another and which also develop the invention independently of one another. Therefore, the disclosure should also include combinations of the features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by other features of the invention already described.

In the figures, identical reference symbols designate functionally identical elements.

1 shows a schematic representation of a motor vehicle 10 with a battery arrangement 12 according to an embodiment of the invention. In addition, the motor vehicle 10 also has a control device 14 for determining a first temperature T1 in the interior of a battery cell 16 of the battery arrangement 12. The control device 14 can represent a battery control unit. In order to determine this first temperature T1 in the interior of the battery cell 16, the control device 14 uses a temperature model M of the battery arrangement 12 stored in its memory 18. This temperature model M mathematically models the thermal properties and the thermal behavior of the battery arrangement 12. To determine the first temperature T1, this model M1 uses input parameters E1, E2, of which at least one represents a second temperature T2 detected by means of a temperature sensor 20 at a specific location outside the battery cell 16, preferably on the battery cell 16 itself, and another at least one state variable Z. This state variable Z represents a state variable Z that influences a thermal behavior of the battery arrangement 12 and is variable over time, which is assigned to a thermal component or a thermal medium, which is therefore at least thermally in direct or indirect contact with the battery cell 16. This component or medium is either a component of the battery arrangement 12 or an environment 22 of the motor vehicle 10. Preferably, an ambient temperature TU of the environment 22 and also a current vehicle speed v of the vehicle 10 are taken into account as such state variables Z as input variables for the model M. Further advantageous input variables and model parameters of the temperature model M are explained in more detail below, in particular in connection with a more detailed description of the structure of the battery arrangement 12.

This is shown by 2 a schematic representation of a battery arrangement 12 for a motor vehicle 10 according to an embodiment of the invention. This battery arrangement 12 comprises at least one battery module 24, which comprises at least one battery cell 16. In particular, the battery module 24 preferably comprises a plurality of battery cells 16, which can be arranged next to one another in a stacking direction, for example the Y direction shown here. The battery arrangement 12 can also comprise a plurality of such battery modules 24. Each battery cell 16 has a cell housing 17 and two cell poles 26. These can be electrically connected to one another via cell connectors 28. The cell connectors 28 can also be referred to as busbars 28. In this example, the battery cells 16 are designed such that their cell poles 26 are arranged on opposite sides. In this example, the battery cell 16 has a first side 16a, on which a cell pole 26 is arranged, and a further side 16b, which is opposite the first side 16a with respect to the illustrated x-direction, and on which the second cell pole 26 of the cell 16 is arranged. In addition, the Battery cell 16 has a third side 16c, which can also be referred to as the top side without restricting generality, and an opposite fourth side 16d, which can also be referred to as the bottom side. The z-direction shown preferably points in the direction of the vehicle's vertical axis in relation to a preferred intended installation position in a motor vehicle. In principle, however, any other installation positions are also conceivable.

In the present example, the top and bottom sides 16c, 16d are each connected to a cooling device, in particular an upper cooling plate 28 and a lower cooling plate 30. In this example, the battery module 24 has a module housing 32. The module housing 32 comprises, for example, an upper module frame 32a, a lower module frame 32b and a side plate 32c. On the opposite side in the x direction, a further side plate 32c can also be arranged, which is not shown here, however. In addition, the other cell pole 26 can also be electrically connected to other cell poles of neighboring cells via busbars 28. The battery cells 16, which are arranged in the module frame or module housing 32, can be connected with their cell housings 17 to the module frame 32, for example as shown here for the lower module frame 32b and the upper module frame 32a, via a filling material 34, in particular thermally and/or mechanically connected. The filling material 34 can be, for example, a gap filler or a thermal interface material and/or an adhesive. The battery module 24 is in turn connected to the upper cooling plate 28 on the one hand and to the lower cooling plate 30 on the other hand, namely via a thermal interface material 36, which is also referred to as a gap filler. According to a further embodiment, a battery housing part, which can also be referred to as a battery frame part, can be located between the lower cooling plate 30 and the lower module frame part 32b. In this case, it would be preferred for this to be connected to the lower cooling plate 30 via an adhesive layer and on the other side to be connected to the lower module frame part 32b via the gap filler 36. The same can also apply to the upper cooling plate 28, i.e. between this and the upper module frame part 32a there can be an upper battery housing part which is connected to the upper cooling plate 28 via a further, upper adhesive layer and is connected to the upper module frame 32a via the upper gap filler layer 36.

The side plate 32c is also connected via this gap filler 36, in particular via the respective gap filler layers 36, to the upper plate 28 or to the upper battery housing part as well as to the lower cooling plate 30 or to the lower battery housing part. One of the poles 26 is in turn thermally connected to this side plate 32c, for example also via an electrically insulating thermal interface material, preferably in the form of a gap pad 38. Furthermore, the cooling plates 28, 30 are designed such that they each comprise a cooling channel 28a, 30a through which a coolant 40 can flow and through which it flows during operation. The battery arrangement 12 can also have several such battery modules 24. These can be arranged next to one another, for example in or against the x direction. A battery impact protection 42, for example an underrun protection of the motor vehicle 10, is also arranged below the lower cooling plate 30. This impact protection 42 can be arranged on a body component of the motor vehicle 10 and/or on the frame 44 of a battery housing 46 of the battery arrangement 12. In this battery housing 46, the battery module 24 and the optional additional battery modules 24 are arranged. The bottom of the battery housing 46 can be provided, for example, by the lower cooling plate 30 and a cover of the battery housing by the upper cooling plate 28. In principle, however, another design of the cooling device is also conceivable. The 2 The arrangement shown of cell 16 or battery module 24 and the cooling plates 28, 30 arranged thereon can, for example, also be installed rotated by 90° depending on the installation space.

The battery housing 46 is in turn connected to the vehicle body 48 of the motor vehicle 10 or is attached to it, for example screwed to it. In addition, the described battery arrangement 12 is thermally coupled to environmental influences 50 of the environment 22, which are given by the aforementioned ambient temperature TU and the vehicle speed v. These can be detected by means of sensors of the motor vehicle 10 and made available to the control device 14 for determining the first temperature T1.

In the present case, the first temperature T1 in the interior 52 of the battery cell 16 is to be determined. The interior 52 of the battery cell 16 is divided into several areas. In the present case, the interior 52 is divided into a lower area 52a, a central area 52b and an upper area 52c, which in particular includes the corners of the cell 16 in the interior 52. The upper area can also be defined differently, as illustrated for the second upper area 52c'. In addition, a further sub-area 52d is provided, which relates to the cell winding or, in general, the electrode layer arrangement in the interior of the cell housing 17. The corresponding areas 52a, 52b, 52c or 52c' and 52d are designated by dashed lines. It is now advantageously possible for the control device 14 to determine a correspondingly assigned first temperature T1a, T1 b, T1c or T1c' and T1d for each of these areas 52a, 52b, 52c or 52c' and 52d. However, a common average temperature can also be determined as the first temperature T1 for all areas 52a, 52b, 52c or 52c' and 52d. When determining a respective temperature T1a, T1 b, T1c or T1c' and T1d for the respective areas 52a, 52b, 52c or 52c', the temperature distribution within the cell 16 can be based on a certain proportionality. This allows, for example, a heat input into the cell 16 or the power loss generated in the cell 16 to be divided into the individual areas 52a, 52b, 52c or 52c' and 52d according to a certain factor. In addition, a further division into the individual areas 52a, 52b, 52c or 52c' and 52d also enables the modeling of heating from the outside to the inside or in the opposite direction.

The thermal behavior of the battery arrangement 12 in its entirety can be mathematically modeled using the temperature model M already mentioned. In this case, it is advantageous, for example, to first distinguish between active and passive thermal components. Active thermal components or media are those that can actively generate heat or provide a certain cooling capacity. In the present case, these are the cell 16 itself, the cooling plates 28, 30, and the environmental influencing factors 50. These components or influencing factors can change their temperature behavior over time. It is therefore very advantageous to describe these variables using a corresponding state variable Z, which can be recorded regularly or continuously and made available to the model M as input variables E1, E2. For example, it is advantageous to determine the power loss generated by the cell 16 as such input variables E1, E2 and to feed this to the model M to determine the first temperature T1. The power loss can in turn be determined on the basis of electrical variables of the cell 16, for example on the basis of the cell voltage and/or the cell current or other state variables of the cell 16, for example on the basis of the current state of charge.

The individual components of the battery arrangement 12 described above are illustrated by the respective points K1 - K17 and K4' - K8` and K16`, with the battery cell 16 being assigned several points, e.g. the points K1, K2, K8, K8` and K17 for the respective areas 52a, 52b, 52c or 52c' and 52d. This allows the interior 52 of the cell 16 to be modeled more precisely and described thermally, in particular via the thermal behavior of the cell connectors 28 or the anode 26 and cathode 26, i.e. the poles 26 and their internal and external parts, as well as the thermal behavior of the active material or the electrode layer arrangement, e.g. in the form of the cell coil, to which the point K8 is assigned. Above all, the active material temperature T1d is relevant for the performance of the cell 16. The internal materials of the cell 16 only exchange heat with the lower cell material, the middle cell material and the upper cell material, here mainly the cell cup 17, and are significantly influenced by the power loss. The power loss is thus divided between the lower cell material, the middle cell material and the upper cell material, e.g. corresponding to the areas 52a, 52b, 52c`, active material in the area 52d, in particular in the area of the point K17, and cell connectors 28 or poles 26.

Another state variable Z can be given by the heating and/or cooling performance of the respective cooling plates 28, 30. This can be determined, for example, from the mass flow of the coolant 40 that flows through the respective cooling plates 28, 30, and on the basis of the temperatures T3, T4 of the coolant 40 in the first plate 28 and in the second plate 30. It is particularly advantageous to know the coolant temperatures T3, T4 both at the inlet of the respective cooling plate 28, 30 and at the outlet. In order to determine the cooling performance of the cooling plates 28, 30, however, an average coolant temperature T3, T4 is generally sufficient.

Furthermore, it is also advantageous, as already described, to supply both the ambient temperature TU and the vehicle speed v as input parameters E1, E2 to the model M. On the basis of these input variables E1, E2, for example, the power loss of the cell 16 can be determined, which corresponds at least approximately to the heat generated in the cell 16, the cooling or heating power provided by the respective cooling plates 28, 30, and the cooling or heating power of the environment 22.

In addition, the battery arrangement 12 also includes numerous other thermally passive components, for example the cooling plates 28, 30 themselves, the gap filler layers 36, the impact protection 42 and the vehicle body shell 48, the module frame parts 32a, 32b, 32c, other interface materials 34, 38. All of these components can be assigned, for example, a corresponding mass, a specific heat capacity, and a specific thermal resistance or a specific thermal conductivity. On the basis of these variables, which in particular represent corresponding model parameters of the temperature model M len, the thermal behavior of these components can be described. Thus, for each of these components at a given point in time, a corresponding temperature and/or a heat flow W, which is illustrated here as an example by the arrows shown, can be calculated. In the present example, the cell connector 28 acts as a heat source during operation. On the basis of the variables already mentioned, such as cell voltage and cell current, the power loss generated by the cell 16 and in particular by the cell connector 28, which is largely converted into the heat flow W, can be determined. Some of this heat W generated is dissipated via the sheet 32c to the lower cooling plate 30 and/or to the upper cooling plate 28, although not shown here either, and partly introduced into the cell 16. From there, the heat can in turn be dissipated to the outside via the cooling plates 28, 30. How this heat flow W is distributed among the individual components depends in turn on the temperatures of the respective components and their thermal conductivities as well as their specific heat capacities. Because all of these parameters are stored in the temperature model M, the thermal behavior of the battery arrangement 12 can advantageously be mathematically modeled very well. This allows a particularly precise determination of the temperature, in particular basically at any point of this battery arrangement 12, and above all a particularly precise determination of the first temperature T1 in the battery cell 16, in particular even at different areas 52a, 52b, 52c or 52c' and 52d within the battery cell 16.

The temperature model M can basically provide a generic and real-time capable temperature model M which preferably calculates sufficiently stably and, above all, which advantageously uses the existing series sensors, namely existing module temperatures or temperature sensors, outside temperatures or outside temperature sensors, cooling capacity, current and voltage. These variables are typically available to the control device 14 for other purposes anyway. This means that, for example, no additional sensors or other additional components need to be provided in the battery arrangement 12 or generally in the motor vehicle 10 in order to implement the described method for determining the first temperature T1. This additional functionality of more precise determination of the temperature inside the cell 16 can, for example, be carried out and implemented solely by an application program executable by the control device 18 or an algorithm which uses the described model M to calculate the first temperature T1. The temperature model M represents all structural features of the battery arrangement, for example the side busbars 28, the double-sided cooling 28, 30, if present, and other physical dependencies, such as irreversible or reversible power losses. This means that the software executed by the control device 14 can be used to determine the cell temperature T1 across all projects, i.e. in all vehicles 10 with such a battery arrangement 12. Other structural designs can be taken into account by other model parameters of the mathematical model M. The design of the temperature model M is therefore adapted to the specific structural design of the battery arrangement 12, which is described by the model M.

The individual components K1 - K17 and K4' - K8` and K16` mentioned are illustrated by the respective points. Only the battery cell 16 is assigned several points K1, K2, K8, K8`, K17 for the respective areas 52a, 52b, 52c or 52c' and 52d. In addition, the respective thermal contact resistances for the respective boundaries between two adjacent components K1 - K17 and K4' - K8' and K16` can be stored as additional model parameters.

In addition, other components of the battery arrangement 12 that are not shown can be taken into account, in particular components adjacent to the cell 16 in or opposite to the y-direction or components located nearby, such as other battery cells 16. In other words, the heat exchange between the cells 16 can also be taken into account and modeled in the model M. The position of the cell 16 within the module 26 can also be taken into account.

A cell separator can also be located between two adjacent cells 16 of the module 26 in the y-direction. This can have different thermal properties, depending on the objective, e.g. thermal insulation in order to thermally decouple the cells 16, or good thermal conductivity for faster heating. This cell separator can also be in the form of a thermal paste or another heat exchanger. Such a cell separator can also represent another such component taken into account in model M.

For temperature determination, initialization with temperatures that are as accurate as possible is also advantageous. Therefore, it is preferred to use the Bat as the starting temperature, especially for all the components K1 - K17 and K4' - K8' and K16'. battery arrangement 12, the temperature measured by the sensor 20 and/or the ambient temperature TU when the battery or the battery arrangement 12 has not been thermally stressed for a long time, so that all materials of the components K1 - K17 and K4' - K8' and K16' have a homogeneous temperature. The temperature can then be calculated for each individual material, i.e. each of the components K1 - K17 and K4' - K8' and K16' of the battery arrangement 12, based on the dependence of the respective influencing variables, for example the corresponding power losses, and the temperature and heat conduction of the neighboring materials.

In order to detect any drift in the values over time, a monitoring function can also check the plausibility of the temperature model and temperature sensor values and mark them as invalid if necessary. In the case of high loads, for example dynamic driving or high cooling performance and so on, larger deviations over time are more plausible than in the case of constant charging or parking or generally a homogeneous load on the cell 16.

Overall, the examples show how the invention can provide improved temperature determination and tempering of a high-voltage battery.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was 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 accepts no liability for any errors or omissions.

Cited patent literature

• DE 102017220547 A1 [0003]
• DE 102017209182 A1 [0005]

Claims (10)

Method for determining a first temperature (T1; T1a, T1b, T1c, T1c', T1d) in an interior (52) of at least one battery cell (16) of a battery arrangement (12), wherein the battery arrangement (12) comprises a battery module (24) with the at least one battery cell (16) and a cooling device (28, 30) for cooling the battery module (24), - wherein a second temperature (T2) is detected by means of at least one temperature sensor (20) which is arranged at a specific point on the battery module (24) outside the at least one battery cell (16); and - the first temperature (T1; T1a, T1b, T1c, T1c', T1d) is determined by a control device (14) as a function of the second temperature (T2); characterized in that - a temperature model (M) of the battery arrangement (12) is provided, - at least one current, time-variable state variable (Z) of a thermal component (10, 16, 28, 30) or of a thermal medium (40; 22) influencing a thermal behavior of the battery arrangement (12) is detected; and - the first temperature (T1; T1a, T1b, T1c, T1c', T1d) is determined by the control device (14) by means of the temperature model (M) and depending on the second temperature (T2) as a first input variable (E2) for the temperature model (M) and depending on the current state variable (Z) as a second input variable (E1) for the temperature model (M). Procedure according to Claim 1 , characterized in that the at least one state variable (Z) relates to the at least one battery cell (16) and/or at least one further battery cell (16) of the battery arrangement (12) and represents at least one of the following: - a power loss currently generated by the battery cell (16) and/or the further battery cell (16); - a current cell current of the at least one battery cell (16) and/or the further battery cell (16); - a current cell voltage of the at least one battery cell (16) and/or the further battery cell (16); - a current state of charge of the at least one battery cell (16) and/or the further battery cell (16). Method according to one of the preceding claims, characterized in that the at least one state variable (Z) relates to the cooling device (28, 30) and represents at least one of the following state variables: - a current cooling or heating power provided by the cooling device (28, 30) for tempering the battery module (24); - a current third temperature (T3, T4) of a coolant (40) of the cooling device (28, 30); - a current fourth temperature of a coolant (40) of the cooling device (28, 30) at an inlet of the cooling device (28, 30); - a current fifth temperature of a coolant (40) of the cooling device (28, 30) at an outlet of the cooling device (28, 30); - a current mass flow of a coolant (40) flowing through the cooling device (28, 30). Method according to one of the preceding claims, characterized in that the at least one state variable (Z) represents a current ambient temperature (TU). Method according to one of the preceding claims, characterized in that the at least one state variable (Z) represents a current speed (v) of the motor vehicle (10) comprising the battery arrangement (12). Method according to one of the preceding claims, characterized in that the battery arrangement (12) has at least one component (16, 26, 28, 30, 32, 32a, 32b, 32c, 34, 36, 38, 42, 44, 46, 48), wherein in the temperature model (M) at least one parameter relating to the at least one component (16, 26, 28, 30, 32, 32a, 32b, 32c, 34, 36, 38, 42, 44, 46, 48) is stored as a model parameter, in particular wherein the parameter - a specific heat capacity of the component (16, 26, 28, 30, 32, 32a, 32b, 32c, 34, 36, 38, 42, 44, 46, 48) represents; and or - a mass of the components (16, 26, 28, 30, 32, 32a, 32b, 32c, 34, 36, 38, 42, 44, 46, 48); and/or - a thermal resistance and/or a thermal conductivity of the component (16, 26, 28, 30, 32, 32a, 32b, 32c, 34, 36, 38, 42, 44, 46, 48); wherein the first temperature (T1; T1a, T1b, T1c, T1c', T1d) is determined as a function of the model parameter. Method according to one of the preceding claims, characterized in that the battery arrangement (12) has at least one component (16, 26, 28, 30, 32, 32a, 32b, 32c, 34, 36, 38, 42, 44, 46, 48), wherein a current sixth temperature of the component (16, 26, 28, 30, 32, 32a, 32b, 32c, 34, 36, 38, 42, 44, 46, 48) and/or a current heat flow associated with the component (16, 26, 28, 30, 32, 32a, 32b, 32c, 34, 36, 38, 42, 44, 46, 48) is determined as a function of a seventh initial temperature of the component (16, 26, 28, 30, 32, 32a, 32b, 32c, 34, 36, 38, 42, 44, 46, 48) is determined, which in a predetermined operating situation of the battery arrangement (12), in particular immediately following a predetermined long inactive phase of the battery arrangement (12) - is determined as the ambient temperature (TU) and/or - the second temperature (T2). Method according to one of the preceding claims, characterized in that a plurality of first temperatures (T1; T1a, T1b, T1c, T1c', T1d) are determined for the battery cell (16), which respectively relate to different regions (52a, 52b, 52c, 52c', 52d) within the battery cell (16). Method according to one of the preceding claims, characterized in that the control device (14) compares the determined first temperature (T1; T1a, T1b, T1c, T1c', T1d) and/or the measured second temperature (T2) with a reference temperature range and generates a signal in the event of a predetermined deviation. Control device (14) for a motor vehicle (10), which is designed to carry out a method according to one of the preceding claims.

Images