METHOD FOR DRYING AN INTERIOR

Abstract

Method for drying an interior (5) of a housing (3) of an electrical energy storage device (2) for a motor vehicle (1), which interior (5) is in fluid communication with an exterior space (7) or is separated from the exterior space (7) depending on a closing state of a pressure equalization device (6) of the energy storage device (2), wherein a drying operation of the electrical energy storage device (2) is carried out based on an overall humidity parameter describing the humidity in the interior (5), in which the humidity, in particular water or water vapor, in the interior (5) is reduced.

Description

[0001] The invention relates to a method for drying 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.

[0002] 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.

[0003] 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.

[0004] To avoid such effects, approaches are known to reduce moisture ingress or to specifically remove moisture from the interior or to bind it within the interior. Examples of known methods for this include moisture-binding substances, in particular granules, membranes or completely enclosed housings. The implementation of these measures is complex and expensive, with particular emphasis on monitoring saturation and, if necessary, replacing the granules, as well as providing and integrating external drying devices into the installation space and operating these devices. In both cases, it is usually not possible to make a defined statement about the humidity level in the interior. In particular, the design of completely enclosed housings is only possible with considerable effort in terms of installation space, weight and cost.

[0005] The invention is based on the object of providing an improved method for drying an interior of a housing of an electrical energy storage device for a motor vehicle.

[0006] The object is achieved by a method according to claim 1. The dependent claims relate to possible embodiments.

[0007] As described, the invention relates to a method for drying 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. The interior of the housing of the electrical energy storage device can thus be brought into fluid communication with the exterior space depending on the closed state of the pressure compensation device. If the pressure compensation device is closed, there is no fluid connection between the interior and the exterior space, apart from leakage and diffusion. If the pressure compensation device is open, a volume exchange is possible through the pressure compensation device, for example a spring-actuated or controllable valve.As described, the pressure equalization device primarily serves to compensate for pressure differences between the interior and exterior spaces by allowing air to flow from the interior to the exterior or vice versa when the pressure equalization device is open. Depending on the different ambient conditions in the interior and exterior spaces, it is possible that humidity can enter the interior of the housing along with the air flowing from the exterior into the interior.

[0008] The invention is based on the finding that, based on an overall humidity parameter describing the humidity in the interior, a drying operation of the electrical energy storage device is carried out in which the humidity, in particular water or water vapor, in the interior is reduced. In other words, it is proposed that an overall humidity parameter describing the humidity present in the interior, in particular over the service life of the motor vehicle or the energy storage device, forms the basis for carrying out the drying operation of the electrical energy storage device. The overall humidity parameter can, in principle, be determined, identified or detected in any way. For example, at least one sensor can be provided to detect the overall humidity parameter. It is also possible to monitor all of the opening and closing processes.The opening duration of the pressure equalization device, possibly taking into account the ambient conditions in the interior and / or exterior, must be considered to determine the total humidity parameter. Depending on the total humidity parameter, it is then possible to execute the drying operation, for example, if the total humidity parameter indicates an increased amount of moisture in the interior. This offers the advantage that the humidity in the interior can then be specifically reduced, which in turn can reduce the total humidity parameter. For example, the total humidity parameter can be recorded and updated again by a sensor, as described.

[0009] According to one embodiment of the method, it can be provided that, during the drying operation, a drying temperature is set as the actual temperature of the electrical energy storage device, in particular of at least one energy storage cell. According to this embodiment, during the drying operation, the energy storage device itself can be used as a "heating device" to set a drying temperature that enables the drying of the interior of the housing of the electrical energy storage device.

[0010] For example, within the thermal monitoring of the energy storage device, which is typically implemented to prevent overheating of the electrical energy storage device, in particular its energy storage cells, it can be used to control or regulate the actual temperature to the desired drying temperature. In particular, it can be provided that the drying temperature is above a typically desired actual temperature or operating temperature of the electrical energy storage device. For example, if the aim is to keep the actual temperature as low as possible during normal operation of the electrical energy storage device, the drying temperature during drying operation can, in contrast, be higher than a normal temperature or operating temperature of the electrical energy storage device in order to promote drying of the interior.

[0011] The described method can further be developed such that the drying temperature is generated by generating a current flow in the electrical energy storage device. The current flow within the electrical energy storage device, for example into an energy storage cell or from an energy storage cell, generates heat that can be used to control the temperature of the energy storage device to the drying temperature. The generated current flow can, for example, be a current generated for an operating state of the electrical energy storage device or an aggregate fed from the electrical energy storage device, for example a current that is provided to an electrical machine of the motor vehicle for its operation. Conversely, the current flow can also be a recuperation current that is fed into the electrical energy storage device.In addition, there is the possibility that the current flow is generated explicitly for the realization of the drying operation.

[0012] The drying temperature can be adjusted by at least one charging process and / or discharging process, in particular by deliberately generating power loss. As described, the discharging processes can be achieved by electrical current flowing from the electrical energy storage device and flowing to an assembly of the motor vehicle or being consumed in at least one assembly of the motor vehicle. It is also possible to deliberately generate power loss through charging processes. In particular, charging processes and discharging processes can be carried out alternately. In this case, the parameters of the electrical machine and / or the electrical energy storage device can be deliberately selected such that the power loss is as high as possible in order to achieve the temperature control of the electrical energy storage device to the drying temperature.

[0013] Furthermore, the method can provide for the drying temperature to be set in an operating state, in particular a driving state of the motor vehicle having the electrical energy storage device, and / or in a charging state. In the operating state, the motor vehicle can be operated in a driving state, for example, moved at a specific speed on a roadway, wherein the electric machine of the motor vehicle is fed from the electrical energy storage device, so that a current flow is generated from the electrical energy storage device into the electric machine, which enables the heating of the electrical energy storage device and thus the increase of the actual temperature to the drying temperature.

[0014] In addition to the operating state of the motor vehicle, the drying operation can also be carried out in a charging state, i.e., when the vehicle is parked. In this case, the electrical energy can be drawn from a charging station or any other charging device, and the charging and / or discharging processes can be carried out alternately, and the actual temperature of the electrical energy storage device can be controlled or regulated to the drying temperature, particularly for a specific drying duration.

[0015] As described, the actual temperature of the electrical energy storage device can be adjusted to the drying temperature by operation, in particular by power loss. In one embodiment of the method, it can be provided that the drying temperature is adjusted by adjusting, in particular reducing, at least one temperature control device. A temperature control device can be assigned to the electrical energy storage device, which controls the temperature of the electrical energy storage device during operation, in particular by cooling it, in order to dissipate heat generated due to power loss or current flows, thus enabling defined operation of the electrical energy storage device.

[0016] The temperature control device can be specifically adjusted during drying operation so that the actual temperature of the electrical energy storage device is increased to the drying temperature. In particular, the temperature control device can be reduced such that the operating temperature or the actual temperature reached during regular operation of the electrical energy storage device or during regular operation of the temperature control device is specifically increased to the drying temperature. In other words, the cooling of the electrical energy storage device can be reduced during drying operation so that the electrical energy storage device heats up to the drying temperature in a defined manner, thus improving the drying of the interior.

[0017] This can be done in particular during reduced operation of the electrical energy storage device or of an electrical machine assigned to the electrical energy storage device. In reduced operation, for example, the full power or torque of the electrical machine is not available, so that heating of the electrical energy storage device can be permitted without risking overload. For example, it is possible to temporarily pause the operation of the temperature control device completely in order to achieve an increase in the actual temperature to the drying temperature. Furthermore, heated or warmed temperature control medium can be supplied to the electrical energy storage device in a targeted manner by means of the temperature control device, so that the electrical energy storage device can be heated to the drying temperature. The temperature control medium can in particular be a liquid temperature control medium guided in temperature control channels.The temperature control channels extend particularly along the energy storage cells, preferably in contact.

[0018] In a further embodiment of the method, it can be provided that the pressure equalization device is opened depending on the overall humidity parameter and / or at least one ambient condition and / or at least one interior condition. The opening can be carried out actively, for example, if the pressure equalization device has a controllable valve. Likewise, the interior conditions can be influenced such that a passive pressure equalization device is opened. Likewise, the pressure equalization device can be completely removed for the duration of the drying process. In other words, the release of air from the interior or the intake of air into the interior can be specifically stimulated.If, for example, the ambient air is comparatively drier and / or warmer than the interior air, it is possible to specifically create an air exchange by opening the pressure equalization device, especially in the case of overpressure in the interior, in order to release moisture from the interior.

[0019] At least one environmental condition can specifically include an outside temperature and / or an ambient air humidity and / or an ambient pressure. Specifically, the environmental conditions can also be related to the currently prevailing indoor conditions, so that temperature differences, humidity differences, or pressure differences can always be taken into account.

[0020] In addition to the method, the invention relates to an electrical energy storage device for a motor vehicle, comprising a housing with an interior space which, depending on a closed state of a pressure equalization device of the energy storage device, is in fluid communication with an exterior space or is separated from the exterior space, wherein the electrical energy storage device is designed to carry out a drying operation of the electrical energy storage device based on an overall humidity parameter describing the humidity in the interior space, in which the humidity, in particular water or water vapor, in the interior space is reduced. The invention further relates to a motor vehicle comprising an electrical energy storage device as described above. The electrical energy storage device is designed to carry out the method with all of the described features.

[0021] All advantages, details, embodiments and / or features described with respect to the method are fully transferable to the electrical energy storage device and the motor vehicle.

[0022] The invention is explained using exemplary embodiments with reference to the figures. The figures are schematic representations and show: Fig. 1 shows a schematic diagram of a motor vehicle comprising an electrical energy storage device according to an embodiment; and Fig. 2 a schematic diagram of a method for drying an interior of an electrical energy storage device.

[0023] Fig. 1 shows a motor vehicle 1 comprising an electrical energy storage device 2 having a housing 3 in which at least one electrical energy storage cell 4 is arranged. The housing 3 delimits an interior space 5 in which the electrical energy storage cell 4 is arranged. The interior space 5 is coupled to an exterior space 7 through the housing 3 by means of a pressure equalization device 6 in such a way that, apart from leakage and diffusion, no fluid connection exists between the interior space 5 and the exterior space 7 when the pressure equalization device 6 is closed, and when the pressure equalization device 6 is open, a volume exchange or an air exchange between the interior space 5 and the exterior space 7 is possible.The pressure equalization device 6 can be understood, for example, as a valve that can be opened and closed actively or passively, for example, when there is an overpressure in the interior space 5, so that air can escape from the interior space 5 into the exterior space 7.

[0024] Conversely, when the pressure equalization device 6 is open, air can also flow from the outside space 7 into the interior space 5, for example when the pressure in the interior space 5 is below zero compared to the outside space 7. A total humidity parameter can be supplied to the electrical energy storage device 2, or a total humidity parameter can be generated, in particular determined or ascertained, for the moisture absorbed in or present in the interior space 5. The total humidity parameter indicates, for example, qualitatively or quantitatively how much moisture has been absorbed in the interior space 5, for example as condensate or water vapor. In principle, it is possible to ascertain the total humidity parameter or to supply it to the electrical energy storage device 2 in any desired manner.A determination device 8 is shown purely schematically, which can determine the humidity in the interior 5, for example, using suitable sensors, such as humidity sensors. It is also possible for the determination device 8 to monitor the opening or closing states, in particular a number of opening operations, opening durations, and the like, of the pressure compensation device 6, thereby determining the humidity in the interior 5.

[0025] Furthermore, the electrical energy storage device 2 has a temperature control device 9, which, for example, during regular operation of the electrical energy storage device 2, is designed to guide temperature control medium through the electrical energy storage device 2, in particular through the housing 3, in order to cool the energy storage cells 4, in particular to dissipate heat caused by the current flow. In order to reduce the humidity in the interior 5, the electrical energy storage device 2 can be operated in a drying mode. In particular, an actual temperature of the electrical energy storage device 2, for example of the energy storage cells 4, is specifically controlled or regulated to a drying temperature so that the interior 5 is heated and can thus be dried.Optionally, the drying temperature can be achieved or supported by appropriate operation of the temperature control device 9, wherein it is also possible to achieve the drying temperature solely by temperature control of the electrical energy storage device 2, for example via a current flow into the energy storage cells 4 or from the energy storage cells 4 or in combination.

[0026] The execution of the process for drying the interior 5 is shown schematically in a flow chart in Fig.2. The method can start in a block 10, in which, as described, the total humidity parameter, specifically from the determination device 8, is supplied to the electrical energy storage device 2, for example, a control device not shown in detail. If the total humidity parameter indicates that the humidity in the interior 5 is above a certain limit, so that drying of the interior 5 is necessary, the method can continue from block 10 to a block 11, in which the drying state is executed or initiated.

[0027] For this purpose, the actual temperature can be controlled or regulated to a defined drying temperature in a block 12. This can be done in particular by generating a power loss within the electrical energy storage device 2. The power loss can be generated in a regular operating state of the motor vehicle 1, for example, by a driving state of the motor vehicle 1. Likewise, for example, in a charge state of the electrical energy storage device 2, targeted charging and discharging processes can be carried out in order to specifically heat the electrical energy storage device 2 to the drying temperature. This can be done in particular in interaction with at least one electrical consumer, specifically an electrical machine of the motor vehicle 1.The electrical consumer, in particular the electric machine, can be operated in an inefficient operating state so that as much power loss as possible is generated, since this is only to be consumed in order to enable rapid heating of the energy storage cells 4.

[0028] Optionally, in a block 13, the previously described temperature control device 9 can also be adjusted accordingly in order to achieve the drying temperature on the part of the electrical energy storage device 2 in order to dry the interior 5. For example, a regular operating state of the temperature control device 9, which is provided for regular operation of the motor vehicle 1 or the energy storage device 2, can be reduced in the drying mode in order to achieve a temperature increase on the part of the energy storage device 2. As a result, the actual temperature of the energy storage device 2 can rise to the drying temperature and be maintained there. Furthermore, it is optionally possible by means of the temperature control device 9 to supply the electrical energy storage device 2 with specifically heated or warmed temperature control medium in order to temperature-control the energy storage device 2 to the drying temperature.This can be achieved, for example, by reducing or temporarily suspending the cooling effect of the temperature control device 9 during drying operation. For example, this can be done in a reduced state of the motor vehicle 1 or the energy storage device 2, in which, for example, a unit assigned to the energy storage device 2 is not supplied with full power, torque, or current, but rather with a reduced operating parameter.

[0029] In a block 14, it is optionally possible to open the pressure equalization device 6 in order to release moisture into the outside space 7, particularly depending on the overall humidity parameter, or to take in drier and / or warmer air from the outside space 7 into the interior space 5 compared to the air in the interior space 5. As previously described, the air exchange between the interior space 5 and the outside space 7 is determined specifically by ambient conditions, for example by the pressure conditions between the interior space 5 and the outside space 7. Depending on the overpressure or underpressure, when the pressure equalization device 6 is opened, air will flow from the outside space 7 into the interior space 5 or from the interior space 5 into the outside space 7. The differences between the interior conditions and the ambient conditions can be determined using suitable sensors, which can also be fed to the determination device 8, for example.If, for example, the air in the outside space 7 is comparatively drier and / or warmer and the pressure in the outside space 7 is higher than in the interior space 5, the pressure equalization device 6 can be opened in a targeted manner so that the drier and warmer air from the outside space 7 can flow into the interior space 5. If, on the other hand, there is excess pressure in the interior space 5 and the air in the interior space 5 is more humid and / or colder than the air in the outside space 7, moisture can be released into the outside space 7 in a targeted manner by opening the pressure equalization device 6.

[0030] The method can also continuously determine, i.e., continuously or at specified intervals, in block 10 how the total humidity parameter is changing and whether the drying operation is still required or is required again. The total humidity parameter can be continuously updated. If the total humidity parameter is below the previously described limit, the drying operation can be discontinued until the total humidity parameter exceeds the limit again.

[0031] As described, the electrical energy storage device 2 is designed to carry out the method for drying the interior 5. All advantages, details, and features described with reference to the figures are therefore transferable to the energy storage device 2 and the motor vehicle 1. List of reference symbols 1 motor vehicle 2 Energy storage device 3 housings 4 energy storage cells 5 Interior 6 Pressure equalization device 7 Outdoor space 8 Determination device 9 Tempering device 10-14 blocks

Claims

[1] Method for drying 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 by that, based on a total humidity parameter describing the humidity in the interior (5), a drying operation of the electrical energy storage device (2) is carried out in which the humidity, in particular water or water vapor, in the interior (5) is reduced. [2] Method according to claim 1, characterized by that in the drying operation a drying temperature is set as the actual temperature of the electrical energy storage device (2), in particular at least one energy storage cell (4). [3] Method according to claim 2, characterized bythat the drying temperature is generated by generating a current flow in the electrical energy storage device (2). [4] Method according to claim 2 or 3, characterized by that the drying temperature is adjusted by at least one charging and / or discharging process, in particular by targeted generation of power loss. [5] Method according to one of the preceding claims, characterized by that the drying temperature is set in an operating state, in particular a driving state of the motor vehicle (1) having the electrical energy storage device (2), and / or in a charging state. [6] Method according to one of the preceding claims, characterized by that the drying temperature is adjusted by adjusting, in particular reducing, at least one tempering device (9). [7] Method according to one of the preceding claims, characterized bythat the pressure compensation device (6) is opened depending on the total humidity parameter and / or at least one ambient condition and / or at least one interior condition. [8] Method according to claim 7, characterized by that the at least one ambient condition comprises an outside temperature and / or a humidity of the ambient air and / or an ambient pressure. [9] Electrical energy storage device (2) for a motor vehicle (1), comprising a housing (3) with an interior space (5) which, depending on a closed state of a pressure compensation device (6) of the energy storage device (2), is in fluid communication with an exterior space (7) or is separated from the exterior space (7), characterized byin that the electrical energy storage device (2) is designed to carry out a drying operation of the electrical energy storage device (2) based on a total humidity parameter describing the humidity in the interior (5), in which the humidity, in particular water or water vapor, in the interior (5) is reduced. [10] Motor vehicle (1) comprising an electrical energy storage device (2) according to the preceding claim.

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