Off-board moisture purge system for battery enclosures

Abstract

A vehicle including a rechargeable energy storage system (RESS) including a RESS housing and at least one battery pack disposed within the housing. A purge air connector is configured to interface with an off-vehicle purge air source, the purge air connector being connected to the rechargeable energy storage system housing via a purge air connection. A controller is controllably coupled to the RESS and the purge air source. The controller is configured to reduce a moisture level within the RESS housing by providing air from the purge air source to the RESS housing through the purge air connection.

Description

Technical Field

[0001] This subject matter discloses a system for blowing moisture out of a vehicle's battery pack, and more particularly, a system that uses an external air source. Background Technology

[0002] Vehicle battery packs, such as those used in electric and hybrid electric vehicles, typically include one or more battery components stored within a housing. These battery components may be susceptible to moisture buildup within the housing caused by condensation, coolant, ambient liquids (such as rainwater), etc. Most battery pack architectures do not include solutions for actively or passively removing liquid once it has formed within the battery pack. The presence of liquid within the battery pack can impair its function and require increased maintenance and downtime of the battery system.

[0003] Therefore, it is desirable to provide a system for purging moisture and liquid from a vehicle battery pack. Summary of the Invention

[0004] In one exemplary embodiment, a vehicle includes a rechargeable energy storage system (RESS) comprising an RESS housing and at least one battery pack disposed within the RESS housing. A purge air duct is configured to interface with an external purge air source and is connected to the rechargeable energy storage system housing via a purge air connection. A controller is controllably coupled to the RESS and the external purge air source. The controller is configured to reduce the moisture level within the RESS housing by delivering air from the external purge air source through the purge air duct to the RESS housing.

[0005] In addition to one or more of the features described in this article, the compressed air is drier than the air currently in the RESS housing.

[0006] In addition to one or more features described herein, the RESS housing includes at least one vent, and the at least one vent is configured to allow air from the RESS housing to exit the RESS housing in response to an air pressure exceeding a threshold amount of the ambient air surrounding the RESS housing.

[0007] In addition to one or more features described herein, at least one vent includes a spring-loaded normally closed vent.

[0008] In addition to one or more features described herein, at least one vent includes a removable panel.

[0009] In addition to one or more features described herein, the purge air duct is a component of the standardized charging port.

[0010] In addition to one or more features described herein, the purge air duct includes a purge air reservoir.

[0011] In addition to one or more features described herein, the purge air reservoir includes a supplemental compressor.

[0012] In addition to one or more features described herein, the purge air duct includes an electrically operated airflow control valve, wherein the electrically operated airflow control valve is controllably connected to a controller.

[0013] In addition to one or more features described herein, the vehicle includes at least one humidity sensor at the RESS, the humidity sensor being configured to determine the air humidity within the RESS.

[0014] In addition to one or more features described herein, at least one humidity sensor includes at least one machine learning-based virtual sensor.

[0015] In addition to one or more features described herein, at least one humidity sensor includes at least one sensor disposed within the RESS housing.

[0016] In addition to one or more features described herein, at least one humidity sensor includes at least one sensor disposed adjacent to the RESS housing.

[0017] In addition to one or more features described herein, reducing the moisture level inside the RESS housing by delivering air from an external purge air source to the RESS housing via a purge air duct includes replacing the air inside the RESS housing with drier air from the external purge air source.

[0018] In addition to one or more features described herein, reducing the moisture level inside the RESS housing includes using outside purge air to reduce the condensation rate inside the RESS housing, evaporating the static liquid inside the RESS housing into the outside purge air, and continuously replacing the purge air with fresh outside purge air for a period of time.

[0019] In addition to one or more features described herein, reducing the moisture level inside the RESS housing includes increasing the pressure inside the RESS housing using external purge air and discharging at least a portion of the static fluid through at least one vent.

[0020] In another exemplary embodiment, a method for reducing moisture within a rechargeable energy storage system (RESS) of a vehicle includes connecting an external purge air source to a purge air connection of the vehicle using a vehicle connector. Purge air is continuously delivered from the external purge air source to the RESS housing via a purge air duct. Air is discharged from the RESS housing through at least one normally closed vent.

[0021] In addition to one or more features described herein, the method further includes storing purge air from an external purge air source in a purge air reservoir, and wherein continuously supplying purge air from an on-board purge air source to the RESS housing via a purge air duct includes connecting the purge air reservoir to a purge air connection.

[0022] In addition to one or more features described herein, continuously supplying purge air from an on-board purge air source to the RESS housing via a purge air duct includes: reducing the moisture content of the air inside the RESS housing to a negative condensation moisture level, and evaporating the static liquid in the RESS housing by maintaining the air in the RESS housing at a negative condensation level for a predetermined duration.

[0023] In addition to one or more features described herein, the purge air duct is incorporated as a component for a standardized charging port.

[0024] The above-described features and advantages, as well as other features and advantages, of this disclosure will become apparent when taken in conjunction with the accompanying drawings and the following detailed description. Attached Figure Description

[0025] Other features, advantages, and details appear by way of example only in the following detailed description, which is described in detail with reference to the accompanying drawings, wherein:

[0026] Figure 1 It includes vehicles with rechargeable energy storage systems and humidity reduction systems;

[0027] Figure 2 This is a schematic representation of a RESS that uses purge air to remove moisture;

[0028] Figure 3A and Figure 3B This illustrates a first example of reducing moisture by lowering the humidity in the RESS; and

[0029] Figure 4A and Figure 4B A second example of reducing moisture by evaporating the static liquid within the RESS is shown. Detailed Implementation

[0030] The following description is exemplary in nature only and is not intended to limit this disclosure, its application, or use. It should be understood that throughout the drawings, corresponding reference numerals denote the same or corresponding parts and features.

[0031] As used herein, the term controller refers to a system that includes at least a processor and memory, wherein the system is configured to perform at least one operation or to have it performed. The system may be a dedicated controller including a single-purpose processor and memory, a general-purpose controller including one or more modules for performing operations, a distributed system including multiple controllers communicating with each other and configured to control operations, or any similar system.

[0032] According to a general embodiment of the system described herein, a hardware-based solution is provided to actively purge humid battery pack air and any liquids formed within the battery pack into the surrounding environment using air from one or more pressurized air sources outside the vehicle. The pressurized air sources may include, but are not limited to, refill / inflator station compressors, rapid inflation systems including purge air capabilities, etc.

[0033] Pressurized air is supplied to the vehicle via a conventional airflow connector and then to the battery pack via a purge air valve. The pressure of the air supplied to the battery pack can be controlled by the corresponding vehicle controller according to any established pressure and / or flow control method. In alternative examples, such as those where compressed air within known parameters is supplied from an external source, compressed air can be provided, pressurized, and forced to exit the battery pack through one or more vents.

[0034] The air supplied to the battery pack is drier (with lower humidity) than the air inside the battery pack and the ambient air. This relative dryness of the purge air reduces humidity within the battery pack. When condensate has already formed inside the battery pack, or when liquid from another source is present in the battery pack, the continued supply of relatively dry purge air via the purge air valve facilitates liquid evaporation. The evaporated liquid is then drained from the RESS as the relatively dry purge air continues to be supplied.

[0035] According to an exemplary embodiment, Figure 1 A vehicle 10 including a rechargeable energy storage system (RESS) 20 is shown. In one example, the RESS 20 includes a housing containing at least one battery component 22. The RESS 20 is connected to a charging port 60 via an electrical connection 62 and a purge airflow duct 64.

[0036] Electrical connection 62 provides a conductive path for current to charge the battery pack 22 within the RESS 20 according to any conventional charging protocol. When charging is required, an operator can connect a vehicle charger to charging port 60 to provide charging from an external power source. In some examples, charging is controlled, in whole or in part, via controller 50.

[0037] exist Figure 1In one example, the purge air duct 64 is a gas flow duct capable of docking with an external compressed gas source 70 and receiving compressed gas at a connector 66. Compressed gas is delivered to RESS 20 via connector 66, thereby allowing RESS 20 to undergo moisture purging. In some examples, an optional purge air reservoir 30 may be integrated with the purge air duct 64 to store the compressed purge air received therethrough. In such an example, the purge air reservoir 30 may be combined in parallel with the purge air duct 64, wherein an electrically controlled valve connects the purge air reservoir 30 to the air flow duct 64 and allows purge air to be redirected to the purge air reservoir. The air in the purge air reservoir can be stored for later moisture reduction operations.

[0038] In some examples, the purge airflow duct 64 can be integrated into a standardized charging system, and the external compressed air source 70 can be integrated into a charging station. In such examples, the vehicle 10 can receive purge air at any time during charging and wet purging can be operated during the charging process.

[0039] In an alternative example, connector 66 may be positioned immediately adjacent to charging port 60 for easy location, or it may be positioned elsewhere on vehicle 10, where the location is determined by vehicle configuration.

[0040] In another example, the purge air reservoir 30 may include a fan or other compressor component to provide supplemental pressurization when the external purge air source 70 is not adequately pressurized. In some examples, one or more components of the vehicle's heating, ventilation, and cooling (HVAC) system may be used to provide the increased pressure.

[0041] The vehicle controller (controller 50) communicates with each of the connector 66, the purge air reservoir 30 (when included), and the RESS 20. In some embodiments, the charging port 60 includes a communication protocol and may also facilitate communication between the controller 50 and an external purge air source. The controller 50 is configured to implement the processes described herein according to any conventional control procedures.

[0042] Continue to refer to Figure 1 vehicles, Figure 2 The RESS 20 is shown in its initial state (RESS 20a) and its purge state (RESS 20b). The RESS 20 includes at least one purge air inlet valve 204 connected to the purge air reservoir 30 or directly connected to the connector 66 via a purge air duct 64. In alternative examples, two or more purge air inlets 204 may be included, each connected to the purge air reservoir 30 and / or the duct 64. Multiple vents 210 are provided in the walls and base of the RESS 20.

[0043] In some examples, vent 210 is a normally closed vent configured to open when the pressure difference between the air pressure inside RESS 20 and the ambient environment exceeds a threshold level. In one such example, vent 210 is a spring-loaded vent, and the threshold level is determined by the spring force of the spring within vent 210.

[0044] In some examples, the vent 210 is a permeable membrane that allows a certain amount of flow through the membrane. In such examples, continued application of pressurized air to RESS 20 ensures that airflow from inside RESS 20 through the membrane to the ambient atmosphere is maintained, thereby preventing backflow.

[0045] In other examples, the vent 210 may include a removable panel configured to be removed by a maintenance technician at the start of a purging operation and replaced by a maintenance technician at the end of a purging operation.

[0046] In some examples, the vent 210 is strategically placed on the RESS 20 to optimize fluid outflow relative to sensitive components (such as high-voltage buses, BDUs, etc.), which may be located adjacent to and / or close to the RESS 20 on the vehicle 10.

[0047] In some examples, the levels of moisture 202 and liquid 208 within RESS 20 can be detected via sensor 212 within RESS 20. In alternative examples, the moisture level can be derived from information from other available sensors.

[0048] In other examples, standard diagnostic and predictive methods used in automotive applications can be used to determine moisture and fluid levels. In some examples, machine learning-based virtual sensors can be used to determine moisture and fluid levels. As used herein, a machine learning-based virtual sensor refers to a machine learning algorithm trained to receive a set of data and predict the likely internal moisture level of the RESS20 based on that set of data. In some examples, one or more data elements within that set of data are not directly related to the moisture level. In some examples, the machine learning algorithm can be trained in a laboratory environment using a combination of empirical and simulated data.

[0049] When the moisture level exceeds a threshold, or when the drying process is started as part of a predetermined operation and / or manually, purge air is supplied through purge air duct 64. The purge air flows into RESS 20b. The incoming purge air displaces the humid air through at least one vent 210, thereby reducing the moisture level within RESS 20b.

[0050] When stagnant liquid 208 has accumulated in RESS 20, in addition to replacing the humid air with drier air, the purge air can further remove the liquid via evaporation. Alternatively, liquid 208 can be removed through a vent 210' located on the bottom wall of RESS 20 (relative to gravity). In this example, the increased pressure generated by supplying drier air to RESS 20 through purge air duct 64 can force liquid 208 to drain directly through vent 210'.

[0051] In another example, the static liquid 208 can be purged from inside the RESS 20 by evaporation. When the purge air is drier than the ambient air and drier than the air inside the RESS 20, the purge air picks up the liquid from the static liquid 208. Purge continues to remove the air, including the evaporated liquid, through the vent 210, thereby reducing or eliminating the static liquid 208.

[0052] In some examples, the RESS20 can reduce the amount of static liquid 208 by using a combination of direct purging of liquid through the vent 210' in the bottom wall and evaporative purging.

[0053] Continue to refer to Figure 1-2 , Figure 3A The RESS20 is schematically shown, which includes multiple humidity sensors (P2, P3, P4, P5). Figure 3B Figure 300 shows, in one example, as the purging process continues, Figure 3A The change of humidity (measured as relative humidity percentage (RH%)) of RESS20 over time.

[0054] Immediately before the purge air circulation, at t0 (0 seconds), the initial air in RESS20 is at an average of 90% humidity and 25 degrees Celsius (°C) as measured by humidity sensors P2, P3, P4, and P5. Purge air begins to be supplied through purge air inlet valve 204. Figure 3A and 3B In one example, the purge air is supplied from a pressurized purge air source with a relative humidity of 10% and a temperature of 25 degrees Celsius. In another example, the purge air inlet valve 204 is an electrically operated airflow control valve and is connected to the controller 50.

[0055] Pressurized purge air is continuously supplied to RESS 20 and mixed with the initial air already inside RESS 20. The mixed air is then removed through outlet valve 210. Figure 3AThe purge air (schematically shown as a single outflowing air stream) reduces the average humidity of the air within RESS 20. The initial influx of purge air provides a significant reduction in humidity, as shown from t0 to t1. As purge air is continuously supplied to RESS 20, the relative humidity within RESS 20 continues to decrease, with the rate of decrease slowing down, resulting in the curve shown in Figure 300. Once the relative humidity within RESS 20 reaches the same relative humidity as the purge air supplied through purge inlet valve 204 (at time t3), the decrease tends to plateau.

[0056] Continuing to supply purge air after time t3 will maintain a low relative humidity, but will not continuously reduce the relative humidity to below the relative humidity of the supplied air.

[0057] In a practical implementation, the slope of graph 300 over times t0, t1, t2, and t3 can typically be determined through empirical testing and / or simulation, and the graph can be stored in controller 50. Multiple individual graphs 300 under each of multiple temperature combinations (purge air temperature and initial RESS 20 air temperature) can be stored and referenced by controller 50.

[0058] Continue to refer to Figure 1-3B , Figure 4A The RESS 20 is shown with liquid 208 accumulated therein. Liquid 208 is the result of condensation, accidental leakage through one or more vents 210, and / or any other liquid source. Figure 4B Graph 400 shows the condensation rate (Y-axis) as a function of time (X-axis). At the initial time (T0), the humidity level is high (see...). Figure 3A , 3B And the condensation rate similarly increases, thereby driving the level of liquid 208 in RESS20 to continue to increase due to condensation.

[0059] When purge air is supplied through purge air inlet valve 204, the condensation rate decreases due to the reduced moisture content in the air until the condensation rate approaches zero at time t4. After reaching zero, the condensation rate continues to decrease below zero, resulting in evaporation (i.e., negative condensation). Continuing to supply drier air through purge air inlet valve 204 will continue to drive evaporation until the point of maximum evaporation (minimum condensation) is reached at t5.

[0060] It is understandable that the maximum evaporation point t5 may be affected by multiple factors, including the dew point, and is not necessarily the time when the minimum relative humidity is reached with RESS20. Figure 3B The same time point as t3 in Figure 300. In this case, the duration of the purging may exceed the amount of time required to reduce the humidity of the air inside RESS20.

[0061] Refer again Figure 1-2 In some examples, sensor 212 may be used to detect the moisture level and provide the detected moisture level to controller 50. In such examples, when the moisture level exceeds a predetermined threshold, controller 50 provides a maintenance notification to the vehicle operator indicating the presence of liquid in RESS 20. In some examples, the operator may then schedule vehicle maintenance, and purging may be provided during the maintenance. In alternative examples, the operator may use any external purging air source to perform the purging.

[0062] In another example, using a purging air process to remove moisture from the RESS20 can be performed as a routine preventative maintenance procedure and included in scheduled maintenance, much like an oil change.

[0063] In some examples, maintenance may include removing one or more side panels of the RESS 20 before initiating the purging process. In this example, one or more of the vents 210 located on the side of the RESS 20 include a panel portion that connects the vent 210 to the wall of the RESS 20. By removing the vents (including the panel portion), the flow rate of purging air through the RESS 20 can be significantly increased, thereby reducing the time required to achieve the evaporation process.

[0064] The terms “a” and “an” do not indicate a limitation of quantity, but rather that at least one of the referenced items is present. The term “or” means “and / or” unless the context clearly indicates otherwise. A reference to “an aspect” throughout the specification means that a particular element (e.g., feature, structure, step, or characteristic) described in connection with that aspect is included in at least one aspect described herein and may or may not be present in other aspects. Furthermore, it should be understood that the described elements may be combined in any suitable manner across the aspects.

[0065] When an element, such as a layer, film, region, or substrate, is referred to as being "on" another element, it can be directly on the other element, or there may be intermediate elements present. Conversely, when an element is referred to as being "directly on" another element, there are no intermediate elements present.

[0066] Unless otherwise stated herein, all test standards are the most recent valid standards up to the filing date of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test standard appears.

[0067] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0068] While the foregoing disclosure has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes can be made and equivalents can replace its elements without departing from its scope. Furthermore, many modifications can be made to adapt particular situations or materials to the teachings of this disclosure without departing from its essential scope. Therefore, it is intended that this disclosure be limited to the specific embodiments disclosed, but will include all embodiments falling within its scope.

Claims

1. A vehicle comprising: A rechargeable energy storage system (RESS) includes an RESS housing and at least one battery pack disposed within the RESS housing; The purge air duct is configured to interface with an external purge air source and is connected to the rechargeable energy storage system housing via the purge air connection. as well as A controller, controllably coupled to the RESS and an external purge air source, is configured to reduce the moisture level inside the RESS housing by delivering air from the external purge air source through a purge air duct to the RESS housing, wherein the purge air is drier than the air currently inside the RESS housing.

2. The vehicle according to claim 1, wherein, The RESS housing includes at least one vent, and wherein the at least one vent is configured to allow air inside the RESS housing to exit the RESS housing in response to the air inside the RESS housing exceeding a pressure threshold amount of the ambient air surrounding the RESS housing.

3. The vehicle according to claim 2, wherein, The at least one vent includes at least one of a spring-loaded normally closed vent and a removable panel.

4. The vehicle according to claim 1, wherein, The purge air duct is a component of the standardized charging port.

5. The vehicle according to claim 1, wherein, The purge air duct includes a purge air reservoir.

6. The vehicle according to claim 5, wherein, The purge air reservoir includes a supplemental compressor.

7. The vehicle according to claim 1, wherein, The purge air duct includes an electrically operated airflow control valve, wherein the electrically operated airflow control valve is controllably connected to the controller.

8. The vehicle according to claim 1, wherein, The at least one humidity sensor includes at least one of a machine learning-based virtual sensor, at least one sensor disposed within the RESS housing, and at least one sensor disposed adjacent to the RESS housing.

9. The vehicle according to claim 1, wherein, Reducing the moisture level inside the RESS housing by delivering air from the external purge air source through the purge air duct to the RESS housing includes at least one of the following: replacing the air inside the RESS housing with drier air from the external purge air source and evaporating the static liquid inside the RESS housing into the air, and continuously replacing the air with fresh external purge air for a period of time.

10. The vehicle according to claim 1, wherein, Reducing the moisture level inside the RESS housing includes using external purge air to increase the pressure inside the RESS housing and discharging at least a portion of the static fluid through at least one vent.

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