Method for determining moisture in an interior

Abstract

The invention relates to a method for determining moisture, in particular water or water vapour, in an interior (5) of a housing (3) of an electrical energy storage device (2) for a motor vehicle (1), said interior (5), depending on a closure state of a pressure compensation apparatus (6) of the energy storage device (2), being in fluidic connection with an exterior (7) or being separated from the exterior (7), wherein, in particular on a model basis, an overall moisture parameter of the interior (5) describing the moisture is determined based on a sum of entry parameters determined at different times and / or at different operating points, which entry parameters describe an entry of moisture into the interior (5) at a particular time and / or at a particular operating point.

Description

[0001] Method for determining humidity in an indoor space

[0002] The invention relates to a method for determining humidity, in particular water or water vapor, in an interior space of a housing of an electrical energy storage device for a motor vehicle, which interior space is in fluid communication with an exterior space or is separated from the exterior space depending on a closed state of a pressure compensation device of the energy storage device.

[0003] Energy storage devices for motor vehicles, for example so-called “high-voltage storage devices”, which have a housing in which electrical energy storage cells of the electrical energy storage device are arranged, are generally known from the prior art. Typically, a fluid connection is established between the interior and an environment or the exterior of the housing in order to enable pressure equalization between the interior and the environment. It is known in this case that pressure equalization devices, for example membranes, valves and the like, can be used to establish or break the fluid connection, depending on the closed state. In particular, with pressure equalization devices of this type, it must be taken into account that a fluid connection, i.e. an exchange of air, can also bring about an exchange of or entry of moisture into the interior.For example, water can occur in gaseous form as water vapor or in liquid form, for example as condensate, and thus penetrate into the interior of the housing.

[0004] Increased air humidity can impair the functionality of the electrical energy storage device, for example, causing corrosion effects on metallic components or electrical connectors and also influencing the structural-mechanical properties of components through the storage of liquid or moisture.

[0005] In order to avoid such effects, approaches are known to reduce moisture ingress or to specifically remove moisture from the interior or to bind it in the interior. Examples of known methods for this include moisture-binding substances, in particular granules, membranes or completely closed housings. In particular, the design of completely closed housings can only be achieved with considerable effort in terms of installation space, weight and cost. Even when the moisture ingress is reduced or moisture is bound or removed from the interior, no information is available about the current humidity in the interior, for example whether a moisture-binding substance is already saturated, whether or when active drying is necessary or sufficiently completed.

[0006] The invention is based on the object of specifying an improved method for determining humidity in an interior of a housing of an electrical energy storage device for a motor vehicle.

[0007] The object is achieved by a method according to claim 1. The dependent claims relate to possible embodiments.

[0008] As described, the invention relates to a method for determining humidity, in particular water or water vapor, in an interior space of a housing of an electrical energy storage device for a motor vehicle, which interior space is in fluid communication with an exterior space or is separated from the exterior space depending on a closed state of a pressure equalization device of the energy storage device. In other words, the method described herein is intended to determine the humidity in the interior space of the housing of the energy storage device so that a statement can be made about the humidity or the amount of water within the housing. A purely qualitative statement or a quantified statement is possible, so that, for example, a decision can be made as to whether further action, such as maintenance or drying of the interior, is necessary.

[0009] The invention is based on the finding that, in particular model-based, a total humidity parameter of the interior describing the humidity is determined based on a sum of input parameters determined at different times and / or at different operating points, which input parameters describe an input of moisture into the interior at a specific time and / or at a specific operating point. The determined total humidity parameter indicates how much moisture is currently absorbed in the interior. The total humidity parameter can, for example, be stored as a unitless number in the form of a counter, or it is possible for the total humidity parameter to specify, for example, a percentage, a mass, or a volume.

[0010] The total humidity parameter is determined from the sum of the entry parameters that describe the entry of moisture into the enclosure for different points in time or operating points. In principle, the entry parameter can be positive, particularly when moisture enters the interior from the outside. It is also possible for the entry parameter to be negative, particularly when moisture is released from the interior to the outside. As is well known, the entry of moisture from the outside into the interior or vice versa is determined based on the ambient conditions, i.e. how much moisture is currently absorbed in the air in the outside and the interior and how the conditions are adjusted when the fluid connection is established by opening the pressure equalization device, and in particular in which direction air flows when the pressure equalization device is opened.

[0011] The input parameter can be determined for different points in time and / or operating points, in particular over the service life of the electrical energy storage device or the electrical energy storage device, so that the amount of moisture, at least qualitatively, absorbed within the interior can be determined at any time. This means that complex retrofitting in the sense of a hardware change for energy storage devices in the field is not necessary, but the method can be used to determine how the moisture behaves in the interior, in particular how the overall humidity parameter continues to change over the operation of the motor vehicle or the energy storage device. The overall humidity parameter can be determined in particular using a model-based method, i.e. various input parameters can be taken into account and the overall humidity parameter can be calculated from them.In particular, the entry parameters may depend on various other environmental or indoor parameters, which are described below.

[0012] According to one embodiment of the method, it can be provided that at least one input parameter is determined based on a difference in at least one environmental parameter, in particular the temperature and / or the air humidity and / or the air pressure, between the interior and the exterior. As described, the input of moisture into the interior results from the difference between the conditions inside the interior and in the exterior. If the air humidity in the exterior is higher than in the interior, for example when the pressure equalization device is opened, moisture is conveyed into the interior through the volume exchange, in particular when there is excess pressure in the exterior. Likewise, if the humidity in the interior is higher than in the exterior, an input parameter can be negative, so that moisture can be released into the exterior, in particular when the pressure in the exterior is negative.Furthermore, the entry parameter can depend on the temperature and the air pressure. The air pressure determines in particular whether the pressure compensation device is opened and to what extent it is opened, so that a "passive determination" of the opening of the pressure compensation device is possible even if it is not opened, for example, in the manner of a controllable valve by issuing a switching signal. Furthermore, the pressure conditions determine the direction of flow of the air into the interior or out of the interior. In particular, the conditions in the interior and in the exterior can be modeled so that when the pressure compensation device is opened or through diffusion and leakage, the entry parameter can be determined on a model-based basis across all times or operating points. This parameter then results, in particular when summed up, in the total humidity parameter.

[0013] The described method can further be developed such that the at least one environmental parameter is determined indirectly, in particular based on navigation data and / or weather data, or directly, in particular based on data from an environmental sensor. For example, it is possible to determine altitudes or altitude differences during operation of the motor vehicle based on navigation data. When driving along a route profile that has corresponding altitude differences, it can be determined whether this causes the pressure equalization device to open, so that air exchange is possible. Furthermore, entry parameters due to leakage or diffusion can be determined from the resulting pressure differences. The environmental parameter can also be determined using weather data, for example retrieved from a weather database.The weather data may include, in particular, temperature, humidity, precipitation, air pressure, and the like. It is also possible to determine the at least one environmental parameter directly, for example, using a pressure sensor, temperature sensor, precipitation sensor, humidity sensor, and the like.

[0014] Furthermore, the method can provide for at least one input parameter to be determined directly or indirectly based on the closed state of the pressure compensation device. As described, the closed state of the pressure compensation device determines the main component for the fluid connection between the interior and the exterior. In addition to the pressure compensation device, leakage or diffusion is possible, which is significantly lower than the volume flow through the open pressure compensation device. By determining the closed state of the pressure compensation device, the input parameter can thus be determined. In particular, in conjunction with the at least one environmental parameter, it is therefore possible to determine how the humidity in the interior changes, which can be output as the overall humidity parameter.

[0015] As described, the pressure compensation device can generally be a passive element, in particular a spring-operated valve. It is also possible for the pressure compensation device to have at least one switchable valve. In the first case, for example, the opening of the pressure compensation device can be determined when pressure differences are detected, for example, when a certain differential pressure is reached, so that the spring-operated valve opens. In the second described case, the switching signals supplied to the pressure compensation device can be analyzed. Ultimately, it is therefore possible to count how often and for how long the pressure compensation device was open in order to determine the moisture ingress.

[0016] Specifically, it is possible for at least one input parameter to be determined as a function of an opening state, in particular an opening process and / or an opening duration, of the pressure equalization device, and / or for at least one input parameter to be determined as a function of a time period within a specific environment. Specifically, different input parameters can be combined with one another, for example, an input parameter that describes the entry of moisture through opening of the pressure equalization device with an input parameter that describes the remaining of the electrical energy storage device in a specific environment. This also allows, in particular, leaks and diffusion-related effects to be included.

[0017] According to a further embodiment of the method, the total humidity parameter can have or include a first counter describing the opening states of the pressure compensation device in a first environment and a second counter describing the opening states of the pressure compensation device in a second environment. This makes it possible to distinguish, based on different counters, how long or how often the pressure compensation device was or was opened in which environment or which type of environment. The environments can differ based on their environmental parameters. For example, the first environment can represent a comparatively dry and / or comparatively cool environment. The second environment, in contrast, can represent a more humid and / or warmer environment.

[0018] This makes it possible to classify the effect of the opening states in relation to the resulting ingress of moisture into the interior. If the pressure equalization device is opened, for example, in the first environment, i.e. in comparatively dry and warm ambient conditions, this leads to a comparatively low ingress of moisture or even a negative ingress, i.e. a discharge, of moisture, so that moisture can be released into the environment. If, on the other hand, the pressure equalization device is opened in the second environment, cold and / or humid air can penetrate into the interior and thus increase the ingress of moisture. The distinction between the at least one first environment and the at least one second environment can be made, for example, on the basis of weather data, GPS data, ambient conditions and the like.

[0019] As described, the total humidity parameter is preferably maintained continuously throughout the service life of the motor vehicle or the electrical energy storage device. The total humidity parameter is therefore stored in a permanent memory, for example an EEPROM. Even when the motor vehicle is at rest, the total humidity parameter is therefore not deleted or "forgotten." Instead, the total humidity parameter is stored permanently and, if necessary, read out again when the motor vehicle is started. The use of the described meters allows, in particular, the evaluation of GPS data, although only the meter is stored. As a result, the described meters are detached from personalized data and it is not necessary to store GPS data, for example, about a traveled route.

[0020] According to a further embodiment of the method, it can be provided that at least one entry parameter, in particular by means of a constant entry term, describes an entry of moisture through leakage and / or through diffusion. As described, the entries caused by leakage and / or through diffusion lead to a significantly smaller proportion of the change in humidity in the interior compared to an opening of the pressure equalization device. These can be described, for example, by constant entry terms, which can optionally be selected differently depending on the environment. It is also possible for the entry parameter describing the entry of moisture through leakage and / or through diffusion to be variable due to environmental parameters, i.e. to represent a function of the environmental parameters. In particular, as already described, this can be based on weather data, sensor data and the like.This also allows environmental influences on the interior of the electrical energy storage device to be taken into account, for example when the motor vehicle is not in operation but has an effect on the housing of the electrical energy storage device via the change between day and night, or when it remains in an air-conditioned garage and is moved into the environment.

[0021] As already described, it is fundamentally possible for the pressure equalization device to be controlled in a targeted manner, for example the closed state of the pressure equalization device can be specifically adjusted. According to one embodiment of the method, it can be provided that the pressure equalization device is opened as a function of the total humidity parameter and / or a current input parameter. For example, this can be carried out by outputting a switching signal to the pressure equalization device, so that the pressure equalization device, for example a controllable valve, opens. If the total humidity parameter, in particular compared to the current ambient conditions, shows that the humidity in the interior is higher than in the exterior, moisture can be specifically released from the interior to the exterior by specifically opening the pressure equalization device, in particular if there is excess pressure in the interior.This is especially the case if a negative input, i.e., a moisture release, is determined for the current input parameter. The release of moisture can, in turn, be recorded in the overall moisture parameter, which can be "updated" by the targeted release of moisture.

[0022] The method can further provide for the total humidity parameter to be output and / or for a maintenance measure to be carried out depending on the total humidity parameter. For example, the total humidity parameter can be output via a display device of the motor vehicle or a user. Furthermore, a maintenance measure can be carried out depending on the total humidity parameter, for example, the user of the motor vehicle can be called to visit a workshop or, during a service measure, the total humidity parameter can be read out. In particular, it is possible to use the total humidity parameter to indicate the amount of water in the interior and, based on this, to decide which maintenance measure, for example, drying, should be carried out.

[0023] In addition to the method, the invention relates to a determination device for determining humidity, in particular water or water vapor, in an interior space of a housing of an electrical energy storage device for a motor vehicle, which interior space is in fluid communication with an exterior space or is separated from the exterior space depending on a closed state of a pressure compensation device of the energy storage device, wherein the determination device is designed, in particular in a model-based manner, to determine an overall humidity parameter of the interior space describing the humidity based on a sum of entry parameters determined at different times and / or at different operating points, which entry parameters describe an entry of moisture into the interior space at a specific time and / or at a specific operating point.The invention further relates to a motor vehicle comprising an electrical energy storage device and a previously described determination device. The determination device is particularly designed to carry out the previously described method in all its details.

[0024] All advantages, details, embodiments and / or features described with regard to the method are fully transferable to the determination device and the motor vehicle.

[0025] The invention is explained using exemplary embodiments with reference to the figures. The figures are schematic representations and show:

[0026] Fig. 1 is a schematic diagram of a motor vehicle comprising an electrical energy storage device and a determination device according to an embodiment; and

[0027] Fig. 2 is a schematic diagram of a flow chart of the method according to an embodiment.

[0028] Fig. 1 shows a motor vehicle 1, comprising an electrical energy storage device 2 with a housing 3 and at least one energy storage cell 4, which is arranged in the housing 3. The housing 3 has an interior space 5, which is in fluid communication with an exterior space 7, for example an environment of the motor vehicle 1, via a pressure compensation device 6, or the fluid connection can be established as required. When the pressure compensation device 6 is closed, there is no fluid connection or the fluid connection is interrupted. When the pressure compensation device 6 is open, the fluid connection is established in that the pressure compensation device 6, for example a spring-actuated valve, is opened.

[0029] The motor vehicle 1 further comprises a determination device 8 configured to carry out a method for determining humidity in the interior 5 of the housing 3. Specifically, the determination device 8 can determine a total humidity parameter of the interior 5, which describes which moisture is absorbed in the interior 5, for example, as condensed water or water vapor.

[0030] The determination device 8 can be connected to an external source 9, for example, a navigation device that can provide the GPS data of the motor vehicle 1 and / or to a weather database that indicates the current weather in the surroundings or in the exterior space 7 of the motor vehicle 1. Furthermore, the determination device 8 can be coupled to at least one environmental sensor 10, which can, for example, comprise a temperature sensor and / or a pressure sensor and / or a humidity sensor. The external source 9 and the environmental sensor 10 are merely optional.

[0031] The method performed by the sealing device 8 is explained below using the schematic flow diagram in Fig. 2. The method can start in a block 11, in which the current total humidity parameter, i.e. the total humidity parameter determined up to the current service life, can be read from a permanent memory, for example an EEPROM. Advantageously, the total humidity parameter can therefore be stored permanently and continued over the entire service life of the energy storage device 2, so that it is not lost when the motor vehicle 1 is in idle mode or switched off. When the motor vehicle 1 is switched off, the total humidity parameter maintained up to that point can be stored again in the permanent memory.

[0032] The method can be continued in block 12, in which entry parameters for the current time or for the current operating point are determined. The entry parameters describe the current entry of moisture into the interior space 5 or from the interior space 5 into the exterior space 7. In principle, the entry parameters can therefore be positive or negative and can therefore increase or decrease the total humidity parameter. In principle, it is possible to branch from block 12 to block 13 or block 14. In block 13, an entry parameter is determined which describes the entry of moisture due to an opening of the pressure equalization device 6. This can be determined, for example, indirectly or passively using a specific pressure difference between the interior space 5 and the exterior space 7.The pressure difference can in turn be determined indirectly by an altitude difference of a route profile of the motor vehicle 1, for example from the external source 9, in particular the altitude data, which can be part of the GPS data.

[0033] In block 14, an entry parameter can be determined that can describe the entry of moisture caused by leakage and / or diffusion. These can be constant terms that, for example, with knowledge of the environment, influence the humidity in the interior space 5 in a constant or approximately constant manner, since, for example, a constant entry of moisture occurs during operation in a comparatively warm and humid environment. Both the entry parameter in block 13 and the entry parameter in block 14 can be implemented as functions of environmental parameters, so that a model-based determination of the overall humidity parameter is possible. For example, data from at least one environmental sensor 10 can be used. Weather data can also be consulted. In principle, the entry parameters can thus be specified depending on the current boundary conditions in the interior space 5 and in the exterior space 7.In particular, humidity differences between the air in the interior space 5 and in the exterior space 7 can be determined and the entry parameter can thereby be determined.

[0034] The total humidity parameter can then be updated based on the current input parameters, for example, for the number of opening states, the duration of the opening states, the duration of operation in the specific environment, and the like. The total humidity parameter can be updated and continued in particular in block 15. The total humidity parameter can have a first counter and a second counter. Depending on the current ambient conditions, the total humidity parameter from block 15 can therefore change a first counter in a block 16 or a second counter in a block 17. The first counter can, for example, basically represent the number of opening states of the pressure compensation device 6 in environments that are not critical for moisture input, and the second counter can represent the number of opening states and / or the duration of the opening states for critical environments.For example, the environments can be separated into first environments and second environments. First environments can be understood as comparatively dry and / or cool environments. Relative humidity and / or temperature can therefore be used as a demarcation criterion. The second environments, in contrast, are warmer and / or more humid environments. The first counter can thus generally relate to the number of opening states and / or the duration of the opening states of the pressure compensation device 6. The second counter can be used for critical moisture inputs; for example, it can be used to determine how much moisture has accumulated in the interior space 5.

[0035] Based on the overall humidity parameter, for example, in block 15, at least one measure can be taken. Specifically, the overall humidity parameter, i.e., a message about the current humidity level of the interior 5, can be output. This can trigger a measure, such as a service measure, maintenance, drying, and the like.

[0036] The advantages, details, and features described in the individual exemplary embodiments can be combined with one another as desired, are interchangeable, and are transferable to one another. The motor vehicle 1, in particular the determination device 8, is fully designed to implement the method described in Fig. 2.

[0037] List of reference symbols

[0038] 1 motor vehicle

[0039] 2 Energy storage device 3 Housing

[0040] 4 energy storage cells

[0041] 5 Interior

[0042] 6 Pressure equalization device

[0043] 7 Outdoor space 8 Determination device

[0044] 9 external source

[0045] 10 Environmental sensor

[0046] 11-17 Blocks

Claims

CLAIMS 1. Method for determining humidity, in particular water or water vapor, in an interior space (5) of a housing (3) of an electrical energy storage device (2) for a motor vehicle (1), which interior space (5) is in fluid communication with an exterior space (7) or is separated from the exterior space (7) depending on a closed state of a pressure equalization device (6) of the energy storage device (2), characterized in that, in particular in a model-based manner, an overall humidity parameter of the interior space (5) describing the humidity is determined based on a sum of entry parameters determined at different times and / or at different operating points, which entry parameters describe an entry of moisture into the interior space (5) at a specific time and / or at a specific operating point.

2. Method according to claim 1, characterized in that at least one entry parameter is determined based on a difference in at least one environmental parameter, in particular the temperature and / or the air humidity and / or the air pressure, between the interior space (5) and the exterior space (7).

3. Method according to claim 2, characterized in that the at least one environmental parameter is determined indirectly, in particular based on navigation data and / or weather data, or directly, in particular based on at least one environmental sensor.

4. Method according to one of the preceding claims, characterized in that at least one input parameter is determined directly or indirectly based on the closed state of the pressure compensation device (6).

5. Method according to one of the preceding claims, characterized in that at least one input parameter is determined as a function of an opening state, in particular an opening process and / or an opening duration, of the pressure compensation device (6) and / or at least one Entry parameters are determined depending on a period of time within a specific environment.

6. Method according to one of the preceding claims, characterized in that the total humidity parameter comprises a first counter describing opening states of the pressure compensation device (6) in a first environment and a second counter describing opening states of the pressure compensation device (6) in a second environment.

7. Method according to one of the preceding claims, characterized in that at least one entry parameter, in particular by means of a constant entry term, describes an entry of moisture by leakage and / or by diffusion.

8. Method according to one of the preceding claims, characterized in that the pressure compensation device (6) is opened as a function of the total moisture parameter and / or a current input parameter.

9. Method according to one of the preceding claims, characterized in that the total humidity parameter is output and / or a maintenance measure is carried out depending on the total humidity parameter.

10. Determination device (8) for determining humidity, in particular water or water vapor, in an interior space (5) of a housing (3) of an electrical energy storage device (2) for a motor vehicle (1), which interior space (5) is in fluid communication with an exterior space (7) or is separated from the exterior space (7) depending on a closed state of a pressure compensation device (6) of the energy storage device (2), characterized in that the determination device is designed, in particular model-based, to determine a total humidity parameter of the interior space (5) describing the humidity based on a sum of input parameters determined at different times and / or at different operating points, which input parameters Describe the entry of moisture into the interior (5) at a specific time and / or at a specific operating point.

11. Motor vehicle (1) comprising an electrical energy storage device (2) and a determination device (8) according to the preceding claim.

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