WO2019226764A1

WO2019226764A1 - Vent for a battery module

Info

Publication number: WO2019226764A1
Application number: PCT/US2019/033509
Authority: WO
Inventors: Xugang Zhang; Ken Nakayama; Judson W. RIGGINS; Richard M. DEKEUSTER
Original assignee: Johnson Controls Technology Company
Priority date: 2018-05-22
Filing date: 2019-05-22
Publication date: 2019-11-28

Abstract

Embodiments of the present disclosure are directed to a breathable vent plug that includes a vent plug portion and a breathable vent portion. The breathable vent portion according to various embodiments may be disposed within the vent plug portion to enable relatively low flow rates of gas to flow into and out of the battery module housing, while maintaining liquid tightness. Further, the vent plug portion may include a seal that is configured to rupture and/or otherwise dislodge both the vent plug portion and the breathable vent portion to enable a quick release of pressure from within the battery module housing.

Description

VENT FOR A BATTERY MODULE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to United States Provisional Patent Application, Serial No. 62/675,025, filed May 22, 2018, entitled VENT FOR A BATTERY MODULE, the entirety of which is hereby incorporated by reference herein.

FIELD

[0002] This application relates to the field of batteries. More specifically, this application relates to venting in a battery module.

BACKGROUND

[0003] The present disclosure relates generally to the field of batteries and battery modules. More specifically, the present disclosure relates to a breathable vent plug for a battery module.

[0004] This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

[0005] A vehicle that uses one or more battery systems for providing all or a portion of the motive power for the vehicle can be referred to as an xEV, where the term“xEV” is defined herein to include all of the following vehicles, or any variations or combinations thereof, that use electric power for all or a portion of their vehicular motive force. For example, xEVs include electric vehicles (EVs) that utilize electric power for all motive force. As will be appreciated by those skilled in the art, hybrid electric vehicles (HEVs), also considered xEVs, combine an internal combustion engine propulsion system and a battery- powered electric propulsion system, such as 48 Volt (V) or 130V systems. The term HEV may include any variation of a hybrid electric vehicle. For example, full hybrid systems (FHEVs) may provide motive and other electrical power to the vehicle using one or more electric motors, using only an internal combustion engine, or using both. In contrast, mild hybrid systems (MHEVs) disable the internal combustion engine when the vehicle is idling and utilize a battery system to continue powering the air conditioning unit, radio, or other electronics, as well as to restart the engine when propulsion is desired. The mild hybrid system may also apply some level of power assist, during acceleration for example, to supplement the internal combustion engine. Mild hybrids are typically 96V to 130V and recover braking energy through a belt or crank integrated starter generator. Further, a micro- hybrid electric vehicle (mHEV) also uses a“Stop-Start” system similar to the mild hybrids, but the micro-hybrid systems of a mHEV may or may not supply power assist to the internal combustion engine and operates at a voltage below 60V. For the purposes of the present discussion, it should be noted that mHEVs typically do not technically use electric power provided directly to the crankshaft or transmission for any portion of the motive force of the vehicle, but an mHEV may still be considered as an xEV since it does use electric power to supplement a vehicle’s power needs when the vehicle is idling with internal combustion engine disabled and recovers braking energy through an integrated starter generator. In addition, a plug-in electric vehicle (PEV) is any vehicle that can be charged from an external source of electricity, such as wall sockets, and the energy stored in the rechargeable battery packs drives or contributes to drive the wheels. PEVs are a subcategory of EVs that include all-electric or battery electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), and electric vehicle conversions of hybrid electric vehicles and conventional internal combustion engine vehicles.

[0006] xEVs as described above may provide a number of advantages as compared to more traditional gas-powered vehicles using only internal combustion engines and traditional electrical systems, which are typically 12V systems powered by a lead acid battery. For example, xEVs may produce fewer undesirable emission products and may exhibit greater fuel efficiency as compared to traditional internal combustion vehicles and, in some cases, such xEVs may eliminate the use of gasoline entirely, as is the case of certain types of EVs or PEVs.

[0007] As technology continues to evolve, there is a need to provide improved battery module components that are used in xEVs. For instance, existing battery modules include breathable vents that enable a pressure within a housing of the battery module to be substantially maintained. An example breathable vent in known lithium ion batteries may comprise a patch which may act as a membrane between the interior of the battery and a vent. ETnfortunately, such breathable vents may not enable a quick pressure release when the housing of the battery module incurs a significant pressure increase. Additionally, existing vent plugs that do quickly release pressure buildup within the housing of the battery module may not be configured to regulate a pressure within the housing of the battery module during normal operation. Using both a breathable vent and a vent plug may complicate assembly and/or otherwise increase manufacturing costs of the battery module.

SUMMARY

[0008] Disclosed is a vent plug for a battery module which may overcome the noted deficiencies. In various embodiments, the vent plug may advantageously provide for breathability for regular pressure regulation in the battery, as well as rapid internal pressure release in the event of such buildup in the battery. The vent plug may allow for breathability at particular pressure level. The vent plug may likewise allow rapid release of pressure from the battery through dislodging of the plug. In addition, the vent plug may advantageously be comprised of material suitable for the battery chemistry.

[0009] Disclosed is a battery system, comprising: a battery module housing; an opening extending through the battery module housing; and a breathable vent plug disposed within the opening; wherein the breathable vent plug comprises a vent plug portion and a breathable vent portion. Further disclosed is a battery system comprising a cover disposed over the breathable vent plug, wherein the cover is configured to block contaminants from entering into the battery module housing via the opening. Further disclosed is a battery system wherein the breathable vent portion of the breathable vent plug comprises pores having small diameters. Further disclosed is a battery system wherein the pores of the breathable vent portion are configured to enable a gas flow into and out of the battery module housing when a pressure within the battery module housing is less than a threshold level while remaining liquid tight. Further disclosed is a battery system wherein the vent plug portion comprises a stem and a coupling portion. Further disclosed is a battery system wherein the coupling portion comprises a securement feature configured to secure the vent plug portion in the opening. Further disclosed is a battery system wherein the stem forms a gap between the vent plug portion and the opening. Further disclosed is a battery system wherein the breathable vent portion is secured in the vent plug portion via an interference fit (it could be a membrane using adhesive). Further disclosed is a battery system wherein a cavity is formed between the breathable vent portion and an end of the vent plug portion.

[0010] Disclosed is a breathable vent plug for a battery module, comprising: a vent plug portion configured to be disposed within an opening of a housing of the battery module, wherein the vent plug portion is configured to be dislodged from the opening of the housing when a pressure in the housing of the battery module exceeds a threshold level; and a breathable vent portion disposed within the vent plug portion, wherein the breathable vent portion is configured to enable a gas flow into and out of the housing of the battery module when the pressure in the housing of the battery module is less than the threshold level. Further disclosed is a breathable vent plug wherein the vent plug portion comprises a coupling portion and a stem. Further disclosed is a breathable vent plug wherein the coupling portion comprises a securement feature configured to secure the vent plug portion within the opening when the pressure in the housing of the battery module is less than the threshold level. Further disclosed is a breathable vent plug wherein the securement feature comprises an O-ring. Further disclosed is a breathable vent plug wherein the breathable vent portion comprises a cylindrical stone or membrane having pores that enable the gas flow into and out of the housing of the battery module when the pressure in the housing of the battery module is less than the threshold level. Further disclosed is a breathable vent plug wherein the pores comprise a diameter of between 0.01 and 0.5 microns, between 0.05 and 0.25 microns, between 0.075 and 0.15 microns, or approximately (e.g., within 10% of, within 5% of, or within 1% of) 0.1 microns. Further disclosed is a breathable vent plug, wherein the breathable vent portion is liquid tight.

[0011] Disclosed herein is a battery system, comprising: a battery module housing; an opening extending through the battery module housing; and a breathable vent plug disposed within the opening, wherein the breathable vent plug comprises a vent plug portion and a breathable vent portion, wherein the vent plug portion comprises a securement feature securing the vent plug portion in the opening, wherein the vent plug portion is configured to be dislodged from the opening when a pressure within the battery module housing exceeds a threshold level, and wherein the breathable vent portion is configured to enable a gas flow into and out of the battery module housing when the pressure within the battery module housing is less than the threshold level. Further disclosed is a battery system wherein the securement feature of the vent plug portion comprises an O-ring. Further disclosed is a battery system comprising a cover disposed over the breathable vent plug, wherein the cover is configured to block contaminants from entering into the battery module housing via the opening. Further disclosed is a battery system wherein the vent plug portion and the breathable vent portion are integral with one another. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which:

[0013] FIG. 1 is perspective view of a vehicle (an xEV) having a battery system contributing all or a portion of the power for the vehicle, in accordance with one or more embodiments of the present approach;

[0014] FIG. 2 is a cutaway schematic view of the xEV of FIG. 1 in the form of a hybrid electric vehicle (HEV), in accordance with one or more embodiments of the present approach;

[0015] FIG. 3 is a perspective view of an embodiment of the battery system of FIG. 1, in accordance with one or more embodiments of the present approach;

[0016] FIG. 4 is a perspective view of an embodiment of a breathable vent plug, in accordance with one or more embodiments of the present approach;

[0017] FIG. 5 A is a cross-section of an embodiment of the breathable vent plug of FIG. 4, in accordance with one or more embodiments of the present approach;

[0018] FIG. 5B is a cross-section of an alternative embodiment of the breathable vent plug of FIG. 4, in accordance with one or more embodiments of the present approach;

[0019] FIG. 5C is cross-section of another alternative embodiment of the breathable vent plug of FIG. 4, in accordance with one or more embodiments of the present approach;

[0020] FIG. 6 is a perspective view of an embodiment of the breathable vent plug, in accordance with one or more embodiments of the present approach;

[0021] FIG. 7 is a cross-section of an embodiment of the breathable vent plug of FIG. 6, in accordance with one or more embodiments of the present approach;

[0022] FIG. 8 is a perspective view of an embodiment of the breathable vent plug, in accordance with one or more embodiments of the present disclosure;

[0023] FIG. 9 is a cross-section of an embodiment of the breathable vent plug of FIG. 8, in accordance with one or more embodiments of the present approach; and

[0024] FIG. 10 is a perspective view of an embodiment of the breathable vent plug, in accordance with one or more embodiments of the present disclosure.

DETAILED DESCRIPTION

[0025] One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers’ specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0026] The battery systems described herein may be used to provide power to various types of electric vehicles (xEVs) and other high voltage energy storage/expending applications (e.g., electrical grid power storage systems). Such battery systems may include one or more battery modules, each battery module having a number of battery cells (e.g., lithium-ion (Li-ion) electrochemical cells) arranged and electrically interconnected to provide particular voltages and/or currents useful to power, for example, one or more components of an xEV. As another example, battery modules in accordance with present embodiments may be incorporated with or provide power to stationary power systems (e.g., non-automotive systems).

[0027] Based on the advantages over traditional gas-power vehicles, manufacturers, which generally produce traditional gas-powered vehicles, may desire to utilize improved vehicle technologies (e.g., regenerative braking technology) within their vehicle lines. Often, these manufacturers may utilize one of their traditional vehicle platforms as a starting point. Accordingly, since traditional gas-powered vehicles are designed to utilize 12 volt battery systems, a 12 volt lithium ion battery may be used to supplement a 12 volt lead-acid battery. More specifically, the 12 volt lithium ion battery may be used to more efficiently capture electrical energy generated during regenerative braking and subsequently supply electrical energy to power the vehicle’s electrical system.

[0028] As advancements occur with vehicle technologies, high-voltage electrical devices requiring voltage higher than 12 volts may also be included in the vehicle’s electrical system. For example, the lithium ion battery may supply electrical energy to an electric motor in a mild-hybrid vehicle. Often, these higher voltage electrical devices utilize voltage greater than 12 volts, for example, up to 48 volts. Accordingly, in some embodiments, the output voltage of a 12 volt lithium ion battery may be boosted using a DC-DC converter to supply power to the high voltage devices. Additionally or alternatively, a 48 volt lithium ion battery may be used to supplement a 12 volt lead-acid battery. More specifically, the 48 volt lithium ion battery may be used to more efficiently capture electrical energy generated during regenerative braking and subsequently supply electrical energy to power the high voltage devices.

[0029] Thus, the design choice regarding whether to utilize a 12 volt lithium ion battery or a 48 volt lithium ion battery may depend directly on the electrical devices included in a particular vehicle. Nevertheless, although the voltage characteristics may differ, the operational principles of a 12 volt lithium ion battery and a 48 volt lithium ion battery are generally similar. More specifically, as described above, both may be used to capture electrical energy during regenerative braking and subsequently supply electrical energy to power electrical devices in the vehicle.

[0030] Accordingly, to simplify the following discussion, the present techniques will be described in relation to a battery system with a 12 volt lithium ion battery and a 12 volt lead- acid battery. However, one of ordinary skill in art is able to adapt the present techniques to other battery systems, such as a battery system with a 48 volt lithium ion battery and a 12 volt lead-acid battery. As another non-limiting alternative, the disclosed may relate to systems (vehicle or otherwise) which use only a lithium ion or other advanced battery.

[0031] The present disclosure relates to batteries and battery modules. More specifically, the present disclosure relates to a breathable vent plug for a battery module that enables a pressure to be substantially maintained within a battery module housing during normal operation (e.g., when a pressure within the battery module housing is less than a threshold level), while also being configured to enable a significant pressure release from within the battery module housing should the pressure in the battery module housing quickly rise above a threshold level. In some embodiments, the threshold level may be an expected internal pressure corresponding to a complete release of cell effluent from any one or a combination of battery cells (e.g., a predetermined number of battery cells) internal to the battery module housing. Particular embodiments are directed to lithium ion battery modules that may be used in vehicular contexts (e.g., hybrid electric vehicles) as well as other energy storage/expending applications (e.g., energy storage for an electrical grid).

[0032] Embodiments of the present disclosure are directed to a breathable vent plug that includes a vent plug portion and a breathable vent portion. The breathable vent portion according to various embodiments may be disposed within the vent plug portion to enable relatively low flow rates of gas to flow into and out of the battery module housing. Further, the vent plug portion may include a seal that is configured to rupture and/or otherwise dislodge both the vent plug portion and the breathable vent portion to enable a quick release of pressure from within the battery module housing. In some embodiments, the breathable vent portion is coupled to the vent plug portion via a weld, an interference fit, heat staking, overmolding, adhesives, another suitable technique, or any combination thereof. In other embodiments, the breathable vent portion is integral with the vent plug portion. In some embodiments, the breathable vent plug may include a cover that is configured to block contaminants from entering into the battery module housing via the breathable vent portion. The cover may include a mesh screen formed from a polymeric material or any suitable shield that blocks contaminants from entering the battery module housing. The breathable vent plug may be understood to therefore be configured to regulate a pressure within the battery module housing under normal operating conditions and to quickly release pressure within the battery module housing when the pressure in the battery module housing reaches a threshold level.

[0033] To help illustrate, FIG. 1 is a perspective view of an embodiment of a vehicle 10, which may utilize a regenerative braking system. Although the following discussion is presented in relation to vehicles with regenerative braking systems, the techniques described herein are adaptable to other vehicles that capture/store electrical energy with a battery, which may include electric-powered and gas-powered vehicles.

[0034] As discussed above, it would be desirable for a battery system 12 to be largely compatible with traditional vehicle designs. Accordingly, the battery system 12 may be placed in a location in the vehicle 10 that would have housed a traditional battery system. For example, as illustrated, the vehicle 10 may include the battery system 12 positioned similarly to a lead-acid battery of a typical combustion-engine vehicle (e.g., under the hood of the vehicle 10). Furthermore, as will be described in more detail below, the battery system 12 may be positioned to facilitate managing temperature of the battery system 12. For example, in some embodiments, positioning a battery system 12 under the hood of the vehicle 10 may enable an air duct to channel airflow over the battery system 12 and cool the battery system 12.

[0035] A more detailed view of the battery system 12 is described in FIG. 2. As depicted, the battery system 12 includes an energy storage component 14 coupled to an ignition system 16, an alternator 18, a vehicle console 20, and optionally to an electric motor 22. Generally, the energy storage component 14 may capture/store electrical energy generated in the vehicle 10 and output electrical energy to power electrical devices in the vehicle 10.

[0036] In other words, the battery system 12 may supply power to components of the vehicle’s electrical system, which may include radiator cooling fans, climate control systems, electric power steering systems, active suspension systems, auto park systems, electric oil pumps, electric super/turbochargers, electric water pumps, heated windscreen/defrosters, window lift motors, vanity lights, tire pressure monitoring systems, sunroof motor controls, power seats, alarm systems, infotainment systems, navigation features, lane departure warning systems, electric parking brakes, external lights, or any combination thereof. Illustratively, in the depicted embodiment, the energy storage component 14 supplies power to the vehicle console 20, a display 21 within the vehicle, and the ignition system 16, which may be used to start (e.g., crank) an internal combustion engine 24.

[0037] Additionally, the energy storage component 14 may capture electrical energy generated by the alternator 18 and/or the electric motor 22. In some embodiments, the alternator 18 may generate electrical energy while the internal combustion engine 24 is running. More specifically, the alternator 18 may convert the mechanical energy produced by the rotation of the internal combustion engine 24 into electrical energy. Additionally or alternatively, when the vehicle 10 includes an electric motor 22, the electric motor 22 may generate electrical energy by converting mechanical energy produced by the movement of the vehicle 10 (e.g., rotation of the wheels) into electrical energy. Thus, in some embodiments, the energy storage component 14 may capture electrical energy generated by the alternator 18 and/or the electric motor 22 during regenerative braking. As such, the alternator 18 and/or the electric motor 22 are generally referred to herein as a regenerative braking system.

[0038] To facilitate capturing and supplying electric energy, the energy storage component 14 may be electrically coupled to the vehicle’s electric system via a bus 26. For example, the bus 26 may enable the energy storage component 14 to receive electrical energy generated by the alternator 18 and/or the electric motor 22. Additionally, the bus 26 may enable the energy storage component 14 to output electrical energy to the ignition system 16 and/or the vehicle console 20. Accordingly, when a 12 volt battery system 12 is used, the bus 26 may carry electrical power typically between 8-18 volts. [0039] Additionally, as depicted, the energy storage component 14 may include multiple battery modules. For example, in the depicted embodiment, the energy storage component 14 includes a lead acid (e.g., a first) battery module 28 in accordance with present embodiments, and a lithium ion (e.g., a second) battery module 30, where each battery module 28, 30 includes one or more battery cells. In other embodiments, the energy storage component 14 may include any number of battery modules. Additionally, although the first battery module 28 and the second battery module 30 are depicted adjacent to one another, they may be positioned in different areas around the vehicle. For example, the second battery module 30 may be positioned in or about the interior of the vehicle 10 while the first battery module 28 may be positioned under the hood of the vehicle 10.

[0040] In some embodiments, the energy storage component 14 may include multiple battery modules to utilize multiple different battery chemistries. For example, the first battery module 28 may utilize a lead-acid battery chemistry and the second battery module 30 may utilize a lithium ion battery chemistry. In such an embodiment, the performance of the battery system 12 may be improved since the lithium ion battery chemistry generally has a higher coulombic efficiency and/or a higher power charge acceptance rate (e.g., higher maximum charge current or charge voltage) than the lead-acid battery chemistry. As such, the capture, storage, and/or distribution efficiency of the battery system 12 may be improved.

[0041] To facilitate controlling the capturing and storing of electrical energy, the battery system 12 may additionally include a control module 32. More specifically, the control module 32 may control operations of components in the battery system 12, such as relays (e.g., switches) within energy storage component 14, the alternator 18, and/or the electric motor 22. For example, the control module 32 may regulate amount of electrical energy captured/supplied by each battery module 28 or 30 (e.g., to de-rate and re-rate the battery system 12), perform load balancing between the battery modules 28 and 30, determine a state of charge of each battery module 28 or 30, determine temperature of each battery module 28 or 30, determine a predicted temperature trajectory of either battery module 28 and 30, determine predicted life span of either battery module 28 or 30, determine fuel economy contribution by either battery module 28 or 30, determine an effective resistance of each battery module 28 or 30, control magnitude of voltage or current output by the alternator 18 and/or the electric motor 22, and the like.

[0042] Accordingly, the control module (e.g., unit) 32 may include one or more processors 34 and one or more memories 36. More specifically, the one or more processors 34 may include one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), one or more general purpose processors, or any combination thereof. Generally, the processor 34 may perform computer-readable instructions related to the processes described herein. Additionally, the processor 34 may be a fixed-point processor or a floating-point processor.

[0043] Additionally, the one or more memories 36 may include volatile memory, such as random access memory (RAM), and/or non-volatile memory, such as read-only memory (ROM), optical drives, hard disc drives, or solid-state drives. In some embodiments, the control module 32 may include portions of a vehicle control unit (VCU) and/or a separate battery control module. Additionally, as depicted, the control module 32 may be included separate from the energy storage component 14, such as a standalone module. In other embodiments, the battery management system (BMS) may be included within the energy storage component 14. In certain embodiments, the control module 32 or the processor 34 may receive data from various sensors 38 disposed within and/or around the energy storage component 14. The sensors 38 may include a variety of sensors for measuring current, voltage, temperature, and the like regarding the battery module 28 or 30. After receiving data from the sensors 38, the processor 34 may convert raw data into estimations of parameters of the battery modules 28 and 30. As such, the processor 34 may render the raw data into data that may provide an operator of the vehicle 10 with valuable information pertaining to operations of the battery system 12, and the information pertaining to the operations of the battery system 12 may be displayed on the display 21. The display 21 may display various images generated by device 10, such as a GUI for an operating system or image data (including still images and video data). The display 21 may be any suitable type of display, such as a liquid crystal display (LCD), plasma display, or an organic light emitting diode (OLED) display, for example. Additionally, the display 21 may include a touch-sensitive element that may provide inputs to the adjust parameters of the control module 32 or data processed by the processor 34.

[0044] The energy storage component 14 may have dimensions comparable to those of a typical lead-acid battery to limit modifications to the vehicle 10 design to accommodate the battery system 12. For example, the energy storage component 14 may be of similar dimensions to an H6 battery, which may be approximately 13.9 inches x 6.8 inches x 7.5 inches. As depicted, the energy storage component 14 may be included within a single continuous housing. In other embodiments, the energy storage component 14 may include multiple housings coupled together (e.g., a first housing including the first battery module 28 and a second housing including the second battery 30). In still other embodiments, as mentioned above, the energy storage component 14 may include the first battery module 28 located under the hood of the vehicle 10, and the second battery module 30 may be located within the interior of the vehicle 10.

[0045] FIG. 3 is a perspective view of an embodiment of the lithium-ion battery module 28 that includes a first battery module terminal 50 and a second battery module terminal 52. The battery module terminals 50, 52 are disposed on a battery module housing 54 and are electrically coupled to one or more battery cells disposed within a cavity of the housing 54. As such, a load or a power supply may be coupled to the battery module terminals 50, 52, such that the lithium-ion battery module 28 supplies and/or receives electrical power. As shown in the illustrated embodiment of FIG. 3, the cavity of the housing 54 is sealed via a cover 56. In some embodiments, the cover 56 is secured to the housing 54 via a weld (e.g., a laser weld), fasteners, another suitable technique, or a combination thereof.

[0046] According to various embodiments, the housing 54 is sealed (e.g., substantially air tight), but may include a breathable vent plug 58 that enables relatively low flow rates of gas to flow into and out of the housing 54. For example, the battery module housing 54 may experience pressure fluctuations as a temperature of the lithium-ion battery module 28 changes due to operation and/or an environment in which the lithium-ion battery module 28 is stored. While lithium-ion batteries are described, further variations in battery types and chemistries should be understood as within the scope of this disclosure. In some cases, the lithium-ion battery module 28 may be exposed to temperatures as low as -40 degrees Celsius (°C) and as high as 80 °C. As such, a pressure differential within the battery module housing 54 may be 5 pounds per square inch (psi), or more. Further, changes in altitude of the lithium- ion battery module 28 may also lead to pressure fluctuations within the battery module housing 54. As such, the breathable vent plug 58 may enable relatively small flow rates of gas to flow into and out of the battery module housing 54 to regulate a pressure within the battery module housing 54 as temperature and altitude vary. In some embodiments, the breathable vent plug 58 includes relatively small pores to allow for gas flow into and out of the battery module housing 54 while remaining liquid tight. Therefore, the breathable vent plug 58 may comprise a range of pore sizes. Pore size may vary, in various embodiments, while allowing for the breathable vent plug to remain liquid tight yet allow gas flow. For example, the breathable vent plug 58 may include pores having a diameter of between 0.01 and 0.5 microns, between 0.05 and 0.25 microns, between 0.075 and 0.15 microns, or approximately (e.g., within 10% of, within 5% of, or within 1% of) 0.1 microns. Accordingly, a flow rate of gas into and out of the battery module housing 54 may be between 0.01 cubic centimeters (cm3/s) and 1 cm3/s, between 0.1 cm3/s and 0.5 cm3/s, between 0.3 cm3/s and 0.4 cm3/s, or approximately (e.g., within 10% of, within 5% of, or within 1% of) 0.35 cm3/s.

[0047] Additionally, the breathable vent plug 58 according to various embodiments is configured to release pressure within the battery module housing 54 when the pressure in the battery module housing 54 reaches a threshold level. In other words, breathable vent plug 58 may allow for quick gas release when pressure within the battery reaches a threshold. For instance, the breathable vent plug 58 is configured to dislodge from an opening 60 of the battery module housing 54 when the pressure reaches the predetermined level. The opening 60 may be significantly larger than the diameter of the pores, such that a relatively large flow rate of gas may exit the battery module housing 54 when the breathable vent plug 58 dislodges from the opening 60. Accordingly, components within the battery module housing 54 may be protected via the release of a relatively high pressure within the battery module housing 54 to increase an operating life of the lithium-ion battery module 28 and/or individual components of the lithium-ion battery module 28.

[0048] As discussed above, the breathable vent plug 58 may include a vent plug portion 80 and a breathable vent portion 82. For example, FIG. 4 is a perspective view of an embodiment of the breathable vent plug 58. As shown in the illustrated embodiment of FIG. 4, the breathable vent portion 82 is disposed within the vent plug portion 80. The breathable vent portion 82 may be secured within the vent plug portion 80 by an interference fit (e.g., a friction fit, prongs, snaps, grooves), a weld, an adhesive, heat staking, overmolding, another suitable technique, or any combination thereof. As discussed above, the breathable vent portion 82 may include pores having a relatively small diameter(s) that enable relatively low flow rates of gasses to flow into and out of the battery module housing 54 via the breathable vent portion 82. In some embodiments, the breathable vent portion 82 includes a membrane formed from a polymeric material, a stone, a metallic material, another suitable material, or any combination thereof. For example, the membrane may include expanded polytetra-fluoro ethylene (E-PTFE) and/or sintered PTFE. In any case, the breathable vent portion 82 is configured to enable relatively low flow rates (e.g., between 0.01 cm3/s and 1 cm3/s, between 0.1 cm3/s and 0.5 cm3/s, or between 0.3 cm3/s and 0.4 cm3/s) of gas to flow into and out of the battery module housing 54 and regulate a pressure within the battery module housing 54 while remaining water or liquid tightness.

[0049] As shown in the illustrated embodiment of FIG. 4, the vent plug portion 80 includes a hose portion 86 (e.g., a stem) and a coupling portion 88. The hose portion 86 may be configured to extend into the opening 60 of the battery module housing 54 to facilitate a flow of gas into and out of the battery module housing 54 through the breathable vent portion 82. The coupling portion 88 is configured to secure the breathable vent plug 58 within the opening 60. For example, the coupling portion 88 may include a securement feature 90, such as an O-ring, a friction fit component, a weld between the coupling portion 88 and the opening 60, an adhesive, or any combination thereof. The securement feature 90 of the coupling portion 88 enables the breathable vent portion 82 to remain substantially stationary with respect to the opening 60 during normal operating conditions of the lithium-ion battery module 28 (e.g., when the pressure within the battery module housing 54 is less than a threshold level). Additionally, the securement feature 90 is configured to dislodge the breathable vent plug 58 from the opening 60 when a pressure within the battery module housing 54 exceeds a threshold level. As such, pressure may be quickly released from within the battery module housing 54 to protect various components (e.g., electrical components) within the battery module housing 54 from incurring significant damage.

[0050] FIG. 5A is a cross-sectional side view of the breathable vent plug 58 disposed within the opening 60. As shown in the illustrated embodiment of FIG. 5 A, the hose portion 86 of the vent plug portion 80 forms a gap 100 (e.g., an annular gap) between an inner surface 102 of the opening 60 and an external surface 104 of the hose portion 86. As such, when pressure within the battery module housing 54 reaches the threshold level, gas within the gap 100 may force the breathable vent plug 58 to become dislodged from the opening 60. Additionally, an inner conduit 106 of the hose portion 86 may facilitate a flow of gasses into and out of the battery module housing 54 via the pores of the breathable vent portion 82.

[0051] As shown in FIG. 5B, the breathable vent plug 58 may comprise a membrane 83 which comprises the breathable vent portion 82. The membrane 83 may be attached into the plug 58 by way of an adhesive or welding. For example, adhesive may be provided around a periphery of the membrane 83 to attach to an internal wall of the plug (for example, an internal wall of the coupling portion 88). In this way, membrane 83 may be one example alternative to a breathable stone. In various embodiments, membrane 83 may be shaped to cover the inner conduit 106. For example, membrane 83 may comprise a circular shape, such as, but not limited to, a circular disk. The membrane, in various embodiments, may comprise a patch.

[0052] As shown in FIG. 5C, the breathable vent plug 58 may be oriented such that hose portion 86 extends away from the battery housing. In this alternative embodiment, gas from an interior of the battery may flow out through the breathable vent portion 82 and then through the hose portion 82.

[0053] In some embodiments, the breathable vent plug 58 includes a cover 108 configured to be disposed over an external surface 110 of the breathable vent portion 82. The cover 108 is configured to block contaminants (e.g., water, salt, and/or dust) from entering the battery module housing 54 via the breathable vent portion 82. In other words, the cover 108 blocks contaminants from flowing into the battery module housing 54 via the pores of the breathable vent portion 82 when a pressure within the battery module housing 54 decreases. Further, the cover 108 may block the contaminants from clogging pores of the breathable vent portion 82, which may ensure that gas may continuously flow into and out of the battery module housing 54 under normal operating conditions of the lithium-ion battery module 28. In various embodiments, the breathable vent plug 58 may be liquid tight or watertight and only allow gas flow in and out of the battery. In some embodiments, the cover 108 may include a shield or mesh sheet that is formed from a polymeric material, a metallic material, or another suitable material.

[0054] In other embodiments, the breathable vent plug 58 includes other shapes and/or sizes than those shown in FIGS. 4, 5A, 5B, and 5C. Indeed, a size of the breathable vent plug 58 may be scaled to fit any sized opening for any suitable battery module. FIGS. 6-10 illustrate embodiments of the breathable vent plug 58 having different configurations from the breathable vent plug 58 of FIGS. 4, 5A, 5B, and 5C. For example, FIGS. 6 and 7 illustrate an embodiment of the breathable vent plug 58, where the vent plug portion 80 does not include the hose portion 86 and/or a length 120 of the hose portion 86 is reduced when compared to the hose portion 86 of FIGS. 4, 5A, 5B, and 5C.

[0055] FIGS. 8 and 9 illustrate example embodiments of the breathable vent plug 58 having a coupling portion 88, which extends along substantially an entire length 132 of the breathable vent plug 58. As shown in the illustrated embodiments of FIGS. 8 and 9, the securement feature 90 may be disposed at approximately (as non-limiting examples, within 25% of, within 10% of, or within 5% of) a midpoint 136 of the length 132 of the breathable vent plug 58. As such, at least a portion 138 of the coupling portion 88 may extend beyond the opening 60 of the battery module housing 54. Additionally or alternatively, the breathable vent plug 58 of FIGS. 8 and 9 may include a cavity 140 formed between the surface 110 of the breathable vent portion 82 and an end 142 of the coupling portion 88. Accordingly, a cover 144 may be positioned at the end 142 of the coupling portion 88 to block contaminants from entering into the cavity 140, and thus, from reaching the breathable vent portion 82. As discussed above, the breathable vent portion 82 may be disposed in the vent plug portion 80 via an interference fit, a weld, an adhesive, heat staking, overmolding, or another suitable method.

[0056] FIG. 10 is an embodiment where the breathable vent portion 82 acts as the vent plug portion 80. In some embodiments, the breathable vent portion 82 is configured to be directly disposed in the opening 60 (e.g., via an interference fit). The breathable vent portion 82 may also be configured to be dislodged from the opening 60 when the pressure within the battery module housing 54 reaches the threshold level. For instance, the breathable vent portion 82 may include a groove 150 configured to receive a securement feature 152, such as an o-ring. The securement feature 152 may form a seal between the breathable vent portion 82 and the opening 60 during normal operating conditions of the lithium-ion battery module 28. The securement feature 152 may also be configured to become dislodged when the pressure in the battery module housing 54 exceeds the threshold level. As such, the breathable vent plug 58 may include single piece that acts as both the breathable vent portion 82 and the vent plug portion 80.

[0057] One or more of the disclosed embodiments, alone or in combination, may provide one or more technical effects including pressure regulation of a battery module. In particular, the battery system or battery module includes a breathable vent plug configured to substantially maintain a pressure within a battery module housing under normal operating conditions and to quickly release pressure from within the battery module housing when the pressure increases above a threshold level. For example, the breathable vent plug may include a plug portion configured to release the pressure from within the battery module housing when the pressure reaches a threshold level. Additionally, the breathable vent plug includes a breathable element that may enable relatively low flow rates of gasses to flow into and out of the housing during normal operating conditions, or when the pressure is less than the threshold level. As such, a performance of the battery module may be improved and components within the battery module may incur an increased operating life. The technical effects and technical problems in the specification are exemplary and are not limiting. It should be noted that the embodiments described in the specification may have other technical effects and can solve other technical problems.

[0058] The specific embodiments described above have been shown by way of example, and it should be understood that these embodiments may be susceptible to various modifications and alternative forms. It should be further understood that the claims are not intended to be limited to the particular forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling within the spirit and scope of this disclosure.

[0059] As utilized herein, the terms“approximately,” “about,” “substantially”, and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims.

[0060] It should be noted that references to relative positions (e.g.,“top” and“bottom”) in this description are merely used to identify various elements as are oriented in the Figures. It should be recognized that the orientation of particular components may vary greatly depending on the application in which they are used.

[0061] For the purpose of this disclosure, the term“coupled” means the joining of two members directly or indirectly to one another. Such joining may be stationary in nature or moveable in nature. Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. Such joining may be permanent in nature or may be removable or releasable in nature.

[0062] It is also important to note that the construction and arrangement of the system, methods, and devices as shown in the various examples of embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements show as multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures and/or members or connector or other elements of the system may be varied, the nature or number of adjustment positions provided between the elements may be varied (e.g. by variations in the number of engagement slots or size of the engagement slots or type of engagement). The order or sequence of any process or method steps may be varied or re- sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the various examples of embodiments without departing from the spirit or scope of the present inventions.

[0063] While this invention has been described in conjunction with the examples of embodiments outlined above, various alternatives, modifications, variations, improvements and/or substantial equivalents, whether known or that are or may be presently foreseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the examples of embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit or scope of the invention. Therefore, the invention is intended to embrace all known or earlier developed alternatives, modifications, variations, improvements and/or substantial equivalents.

Claims

CLAIMS:

1. A battery system, comprising:

a battery module housing;

an opening extending through the battery module housing; and

a breathable vent plug disposed within the opening;

wherein the breathable vent plug comprises a vent plug portion and a breathable vent portion.

2. The battery system of claim 1, comprising a cover disposed over the breathable vent plug, wherein the cover is configured to block contaminants from entering into the battery module housing via the opening.

3. The battery system of claim 1, wherein the breathable vent portion of the breathable vent plug comprises pores having small diameters.

4. The battery system of claim 3, wherein the pores of the breathable vent portion are configured to enable a gas flow into and out of the battery module housing when a pressure within the battery module housing is less than a threshold level while remaining liquid tight.

5. The battery system of claim 4, wherein a flow rate of the gas flow is approximately 0.35 cubic centimeters per second.

6. The battery system of claim 1, wherein the vent plug portion comprises a stem and a coupling portion.

7. The battery system of claim 6, wherein the coupling portion comprises a securement feature configured to secure the vent plug portion in the opening.

8. The battery system of claim 6, wherein the stem forms a gap between the vent plug portion and the opening.

9. The battery system of claim 1, wherein the breathable vent portion is secured in the vent plug portion via an interference fit.

10. The batery system of claim 1, wherein a cavity is formed between the breathable vent portion and an end of the vent plug portion.

11. A breathable vent plug for a battery module, comprising:

a vent plug portion configured to be disposed within an opening of a housing of the battery module, wherein the vent plug portion is configured to be dislodged from the opening of the housing when a pressure in the housing of the battery module exceeds a threshold level; and

a breathable vent portion disposed within the vent plug portion, wherein the breathable vent portion is configured to enable a gas flow into and out of the housing of the battery module when the pressure in the housing of the battery module is less than the threshold level.

12. The breathable vent plug of claim 11, wherein the vent plug portion comprises a coupling portion and a stem.

13. The breathable vent plug of claim 12, wherein the coupling portion comprises a securement feature configured to secure the vent plug portion within the opening when the pressure in the housing of the battery module is less than the threshold level.

14. The breathable vent plug of claim 13, wherein the securement feature comprises an O-ring.

15. The breathable vent plug of claim 11, wherein the breathable vent portion comprises a cylindrical stone or membrane having pores that enable the gas flow into and out of the housing of the battery module when the pressure in the housing of the battery module is less than the threshold level.

16. The breathable vent plug of claim 11, wherein the pores comprise a diameter of between 0.01 and 0.5 microns, between 0.05 and 0.25 microns, between 0.075 and 0.15 microns, or approximately (e.g., within 10% of, within 5% of, or within 1% of) 0.1 microns.

17. A battery system, comprising:

a battery module housing;

an opening extending through the battery module housing; and

a breathable vent plug disposed within the opening, wherein the breathable vent plug comprises a vent plug portion and a breathable vent portion, wherein the vent plug portion comprises a securement feature securing the vent plug portion in the opening, wherein the vent plug portion is configured to be dislodged from the opening when a pressure within the battery module housing exceeds a threshold level, and wherein the breathable vent portion is configured to enable a gas flow into and out of the battery module housing when the pressure within the battery module housing is less than the threshold level.

18. The battery system of claim 17, wherein the securement feature of the vent plug portion comprises an O-ring.

19. The battery system of claim 17, comprising a cover disposed over the breathable vent plug, wherein the cover is configured to block contaminants from entering into the battery module housing via the opening.

20. The battery system of claim 17, wherein the vent plug portion and the breathable vent portion are integral with one another.

21. The breathable vent plug of claim 11, wherein the breathable vent portion is liquid tight.