Vehicle-mounted moisture purge system for battery enclosure

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 source is disposed within the vehicle and is configured to generate compressed air 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 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 using an onboard 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. Current battery pack architectures do not include solutions for actively or passively removing liquids once they have formed within the battery pack. The presence of liquids within the battery pack can impair its function and necessitate increased maintenance and downtime for 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 housing. A purge air source is disposed within the vehicle and configured to generate purge air 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 purge air source. The controller is configured to reduce the moisture level within the RESS housing by providing purge air from the purge air source to the RESS housing via the purge air connection.

[0005] In addition to one or more of the features described in this article, the compressed air is drier than the internal air inside 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 semi-permeable membrane.

[0009] In addition to one or more of the features described herein, the purge air source includes at least one of an air suspension system, heating, ventilation and cooling (HVAC) hardware, and a dedicated electric compressor.

[0010] In addition to one or more features described herein, the purge air connection 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 connection includes an electrically operated airflow control valve, wherein the electrically operated airflow control valve is controllably connected to the 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 within the RESS housing by supplying air from a purge air source to the RESS housing via a purge air connection includes replacing the air within the RESS housing with drier air from the purge air source.

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

[0019] In addition to one or more features described herein, reducing the moisture level within the RESS housing includes using purge air to increase the pressure within the RESS housing 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 is provided. The method includes continuously supplying purge air from an on-board purge air source to the RESS housing via a purge air connection. 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 includes storing purge air from an on-board purge air source in a purge air reservoir, and wherein continuously supplying purge air from the on-board purge air source to the RESS housing via a purge air connection includes connecting the purge air reservoir to the 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 connection 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 vehicle purge air source includes at least one of an air suspension system, heating, ventilation and cooling (HVAC) hardware, and a dedicated electric compressor.

[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 refers to vehicles that include a rechargeable energy storage system and a humidity reduction process;

[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 to the surrounding environment using air from one or more pressurized air sources on the vehicle. The pressurized air sources may include, but are not limited to, air suspension systems, heating, ventilation, and cooling (HVAC) hardware, dedicated electric compressors, or any similar onboard system. Pressurized air is supplied to the battery pack via a purge air valve, wherein the pressure of the air supplied to the battery pack is controlled by the corresponding vehicle controller according to any established pressure and / or flow control method. The pressurized air forces the air currently in the battery pack to leave the battery pack through one or more vents.

[0033] The air supplied to the battery pack is drier (with lower humidity) than the air inside the battery pack or the ambient air. The 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 through the purge air valve facilitates liquid evaporation. The evaporated liquid is then discharged from RESS20 as relatively dry purge air continues to be pumped into RESS20.

[0034] 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 is a housing containing at least one battery component 22. A purge air reservoir 30 is connected to the purge air inlet of the RESS 20. Figure 2 (See purge air inlet valve 204 shown). Purge air reservoir 30 receives and stores air from one or more vehicle systems 40, which are capable of generating and / or utilizing compressed air during their normal operation. In one example, one or more vehicle systems 40 include an air suspension system. In other examples, one or more vehicle systems 40 may include any combination of an air suspension system, heating, ventilation, and cooling (HVAC) hardware, and a dedicated electric compressor. In some examples, the pressurized air generated by one or more vehicle systems 40 may not be sufficient to directly purge the air in RESS 20. In such examples, purge air reservoir 30 stores pressurized air during operation of one or more vehicle systems 40 and discharges the stored pressurized air when purge air is needed.

[0035] In another example, the purge air reservoir may include a fan or other compressor component. The fan or other compressor component provides additional pressure to the purge air. In some examples, one or more components of a vehicle's HVAC system may be used to provide increased pressure via a connection to HVAC ductwork.

[0036] In an alternative example, when one or more vehicle systems 40 can provide sufficient quantity and pressure of compressed air, the purge air reservoir can be omitted, and the pressurized air can be supplied directly to the purge air inlet 204 of the RESS 20. Figure 2 (as shown in the image).

[0037] The vehicle controller (controller 50) communicates with at least one of the vehicle systems 40, the purge air reservoir 30, and the RESS 20. Controller 50 is configured to implement the processes described herein according to any conventional control process.

[0038] 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 via a purge air duct 206. In alternative examples, two or more purge air inlets 204 may be included. Multiple vents 210 are provided in the walls and base of the RESS 20.

[0039] 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.

[0040] 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.

[0041] In some examples, the vent 210 is 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.

[0042] 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.

[0043] 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 this 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.

[0044] When the humidity level exceeds a threshold, or when the drying process is started as part of a predetermined operation and / or manually, purge air is supplied to the purge air duct 206 via valve 204. The purge air flows into RESS 20b. The incoming purge air forces the humid air out through at least one vent 210, thereby reducing the humidity level within RESS 20b.

[0045] When stagnant fluid 208 has accumulated in RESS 20, purge air can further remove the fluid in addition to replacing the humid air with drier air. Liquid 208 can be removed through 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 via purge air connection 206 can force liquid 208 to drain directly through vent 210'.

[0046] In another example, the static liquid 208 can be removed from inside the RESS 20 by evaporation. Since the purge air is drier than ambient air and also drier than the air currently inside the RESS 20, the purge air picks up the liquid from the static liquid 208. Continued purging removes the air, including the evaporated liquid, through vent 210, thereby reducing or eliminating the static liquid 208.

[0047] In some examples, the RESS 20 can reduce the amount of liquid in the static liquid 208 by using a combination of direct purging of the liquid through the vent 210' in the bottom wall and evaporative purging.

[0048] Continue to refer to Figure 1-2 , Figure 3A The RESS20 is schematically shown, which includes multiple humidity sensors (P2, P3, P4, P5). Figure 3BFigure 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.

[0049] 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 is then pumped through purge air inlet valve 204 and enters RESS20. 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.

[0050] Pressurized purge air is continuously supplied to RESS 20 and mixed with the initial air already inside RESS 20. The mixed air is then discharged through outlet valve 210. Figure 3A The purge air (illustrated schematically 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 the purge air continues to flow through RESS 20, the relative humidity within RESS 20 continues to decrease, with the rate of decrease slowing down, resulting in curve 302 shown in Figure 300. Once the relative humidity within RESS 20 reaches the same relative humidity as the purge air (at time t3), the decrease tends to plateau.

[0051] Continuing to deliver 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.

[0052] 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.

[0053] Continue to refer to Figure 1-3B , Figure 4A The RESS 20 is shown with liquid 208 accumulating in its base. 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.

[0054] 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 reaches 0 at time t4. After reaching 0, the condensation rate continues to decrease below 0, 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 maximum evaporation (minimum condensation) level is reached at t5.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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) comprising an RESS housing and at least one battery pack disposed within the housing; A purge air source is located inside the vehicle and configured to generate purge air and be connected to the rechargeable energy storage system housing via a purge air connection; as well as A controller, controllably coupled to the RESS and a purge air source, is configured to reduce the moisture level inside the RESS housing by providing purge air from the purge air source to the RESS housing via a purge air connection, wherein the purge air is drier than the internal air 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 semi-permeable membrane.

4. The vehicle according to claim 1, wherein, The purge air source includes at least one of an air suspension system, heating, ventilation and cooling (HVAC) hardware, and a dedicated electric compressor.

5. The vehicle according to claim 1, wherein, The purge air connection includes a purge air reservoir and optionally a supplemental compressor.

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

7. The vehicle according to claim 1, wherein, The vehicle includes at least one humidity sensor at the RESS, the humidity sensor being configured to determine the humidity of the air inside the RESS, 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.

8. The vehicle according to claim 1, wherein, Reducing the moisture level within the RESS housing by supplying air from the purge air source to the RESS housing via the purge air connection includes replacing the air within the RESS housing with drier air from the purge air source.

9. The vehicle according to claim 1, wherein, Reducing the moisture level inside the RESS housing includes: using the purge air to reduce the condensation rate inside the RESS housing, evaporating the static liquid inside the RESS housing into the purge air, and continuously replacing the purge air with fresh 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 the 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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