Drain valve closure to prevent thermal runaway for a high-voltage battery

Abstract

A vehicle contains a battery and a battery drain assembly. The battery includes a housing and a drain assembly that has a first section inside the housing and a second section outside the housing. A fluid path guides fluid from the battery through the drain assembly. A valve is positioned outside the fluid path. A retaining device holds the valve in the first position. The retaining device is configured to release the valve when an environmental parameter of the battery exceeds a threshold. A preloading device preloads the valve toward a second position within the fluid path.

Description

INTRODUCTION

[0001] The subject matter of the disclosure relates to the prevention of thermal runaway in a battery used in a vehicle, and more particularly to a temperature controlled drain valve for a battery.

[0002] Batteries used in vehicles may contain a drain valve that allows fluid to drain from the battery. Thermal runaway events can sometimes occur in these batteries. During a thermal runaway event, the drain valve can become an unintended path for venting gas from the battery, which can accelerate thermal runaway. Therefore, it is desirable to provide a drain valve that prevents unintended venting. SUMMARY

[0003] According to an exemplary embodiment, a vent assembly for a battery is disclosed. The vent assembly includes a fluid path for the flow of fluid from the battery, a closure disposed in a first position external to the fluid path, a retaining device that holds the closure in the first position, the retaining device configured to release the closure when an environmental parameter of the battery exceeds a threshold, and a biasing device that biases the closure toward a second position in the fluid path.

[0004] In addition to one or more features described herein, the retention device releases the closure when either a temperature in the vent assembly is at or above a temperature threshold or a pressure in the vent assembly is at or above a pressure threshold. The retention device comprises an adhesive material, a shear device, a retractable pin, or a flap. The biasing device comprises a spring within a chamber on one side of the fluid path, an additional mass attached to the closure, or a mass of the closure. The fluid path extends between an inlet within the housing of the battery and an outlet outside the housing, the first position being in a chamber on one side of the inlet and the second position being upstream of the inlet. The vent assembly further includes a vent valve at the outlet of the fluid path.The fluid includes an aqueous fluid, a gas, a coolant, or an electrolytic fluid.

[0005] According to another exemplary embodiment, a battery for a vehicle is disclosed. The battery includes a housing, a vent assembly having a first portion inside the housing and a second portion outside the housing, a fluid path through the vent assembly for the flow of fluid from the battery, a closure disposed in a first position outside the fluid path, a retaining device retaining the closure in the first position, the retaining device configured to release the closure when an environmental parameter of the battery exceeds a threshold, and a biasing device biasing the closure toward a second position in the fluid path.

[0006] In addition to one or more features described herein, the retention device releases the closure when either a temperature in the vent assembly is at or above a temperature threshold or a pressure in the vent assembly is at or above a pressure threshold. The retention device comprises an adhesive material, a shear device, a retractable pin, or a flap. The preloading device comprises a spring within a chamber on one side of the fluid path, an additional mass attached to the closure, or a mass of the closure. The fluid path extends between an inlet in the first section and an outlet in the second section, the first position being in a chamber of the first section on one side of the inlet and the second position being upstream of the inlet. The battery further includes a vent valve at the outlet of the fluid path.The fluid includes an aqueous fluid, a gas, a coolant, or an electrolytic fluid.

[0007] According to another exemplary embodiment, a vehicle is disclosed. The vehicle includes a battery having a housing and a vent assembly. The vent assembly includes a first portion inside the housing and a second portion outside the housing, a fluid path through the vent assembly for the flow of fluid from the battery, a closure disposed in a first position outside the fluid path, a retaining device retaining the closure in the first position, the retaining device configured to release the closure when an environmental parameter of the battery exceeds a threshold, and a biasing device biasing the closure toward a second position in the fluid path.

[0008] In addition to one or more features described herein, the retention device releases the closure when either a temperature in the vent assembly is at or above a temperature threshold or a pressure in the vent assembly is at or above a pressure threshold. The retention device comprises an adhesive material, a shear device, a retractable pin, or a flap. The preloading device comprises a spring within a chamber on one side of the fluid path, an additional mass attached to the closure, or a mass of the closure. The fluid path extends between an inlet in the first section and an outlet in the second section, the first position being in a chamber of the first section on one side of the inlet and the second position being forward of the inlet. The vehicle further includes a vent valve at the outlet of the fluid path.

[0009] The above-described features and advantages and other features and advantages of the disclosure will become apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Further features, advantages and details appear only as examples in the following detailed description, which refers to the drawings; they show: Fig. 1 shows an embodiment of a vehicle including a vehicle body at least partially defining a passenger compartment; Fig. 2 is a side view of a battery pack of the vehicle in an illustrative embodiment; Fig. 3 is a cross-sectional view of the vent assembly in an illustrative embodiment; Fig. Figure 4 is a cross-sectional view of the vent assembly with the closure in the second position; Fig. 5 is a cross-sectional view of the vent assembly in another embodiment; Fig. 6 a cross-sectional view of the drain assembly in another embodiment; and Fig. 7 a cross-sectional view of the drain assembly in another embodiment. DETAILED DESCRIPTION

[0011] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference characters indicate similar or corresponding portions and features.

[0012] According to an exemplary embodiment, Fig. 1 illustrates an embodiment of a vehicle 10 including a vehicle body 12 that at least partially defines a passenger compartment 14. The vehicle body 12 also supports various vehicle subsystems, including a propulsion system 16 and other subsystems to support functions of the propulsion system 16, and other vehicle components such as a braking subsystem, a suspension system, a steering subsystem, and others.

[0013] The vehicle 10 may be an electric vehicle (EV), a hybrid vehicle, or other vehicle. In one embodiment, the vehicle 10 is an electric vehicle that includes multiple motors and / or drive systems. Any number of drive units may be included, such as one or more drive units for applying torque to front wheels (not shown) and / or rear wheels (not shown). The drive units are controllable to operate the vehicle 10 in various operating modes, such as a normal mode, a high-performance mode (in which additional torque is applied), all-wheel drive ("AWD"), front-wheel drive ("FWD"), rear-wheel drive ("RWD"), and others.

[0014] For example, the propulsion system 16 is a multiple drive system that includes a front drive unit 20 for driving front wheels and rear drive units for driving rear wheels. The front drive unit 20 includes a front electric motor 22 and a front inverter 24 (e.g., a front power inverter module or FPIM), as well as other components such as a cooling system. A left rear drive unit 30L includes a left rear electric motor 32L and a left rear inverter 34L. A right rear drive unit 30R includes a right rear electric motor 32R and a right rear inverter 34R. The front inverter 24, the left rear inverter 34L, and the right rear inverter 34R (e.g., power inverter units or PIMs) each convert direct current (DC) power from a high-voltage (HV) battery system 40 to multi-phase alternating current (AC) power (e.g.,Two-phase AC power, three-phase AC power, six-phase AC power, etc.) (multi-phase AC power) to drive the front electric motor 22, the left rear electric motor 32L, and the right rear electric motor 32R.

[0015] As in Fig. As shown in Figure 1, the drive systems comprise separate electric motors. However, embodiments are not so limited. For example, instead of separate motors, multiple drives may be provided by a single machine having multiple sets of windings that are physically independent.

[0016] As in Fig. 1, the drive systems are configured such that the front electric motor 22 drives the front wheels (not shown) and the left rear electric motor 32L and the right rear electric motor 32R drive the rear wheels (not shown). However, embodiments are not so limited, as any number of drive systems and / or motors may be present at various locations (e.g., one motor driving each wheel, partner motors per axle, etc.). Additionally, embodiments are not limited to a dual drive system, as embodiments may be used with a vehicle having any number of motors and / or power inverters.

[0017] In the propulsion system 16, the front-wheel drive unit 20, the left rear-wheel drive unit 30L, and a right rear-wheel drive unit 30R are electrically connected to the battery system 40. The battery system 40 may also be electrically connected to other electrical components (also referred to as "electrical loads") such as vehicle electronics (e.g., via an auxiliary power module or APM 42), heating devices, cooling systems, and others. The battery system 40 may be configured as a rechargeable energy storage system (RESS).

[0018] In one embodiment, the battery system 40 includes a plurality of separate battery assemblies, each of which can be independently charged and used to supply power to a propulsion system or systems. For example, the battery system 40 includes a first battery assembly, such as a first battery pack 44 connected to the front inverter 24, and a second battery pack 46. The first battery pack 44 includes a plurality of battery modules 48, and the second battery pack 46 includes a plurality of battery modules 50. Each battery module 48, 50 includes a number of individual cells (not shown). In various embodiments, one or more of the battery packs may include a MODACS battery (a dynamically adjustable capacity multi-output battery), as described herein with respect to Fig. 2- Fig. 4 is described.

[0019] Each of the front electric motor 22 and the left rear electric motor 32L and the right rear electric motor 32R is a three-phase motor having three-phase motor windings. However, the embodiments described herein are not so limited. For example, the motors may be any multi-phase machines powered by multi-phase inverters, and the drive units may be implemented using a single machine having independent sets of windings.

[0020] The battery system 40 and / or the propulsion system 16 includes a switching system having various switching devices for controlling the operation of the first battery pack 44 and the second battery pack 46 and selectively connecting the first battery pack 44 and the second battery pack 46 to the front drive unit 20, the left rear drive unit 30L, and the right rear drive unit 30R. The switching devices are also operable to selectively connect the first battery pack 44 and the second battery pack 46 to a charging system. The charging system can be used to charge the first battery pack 44 and the second battery pack 46 and / or to supply power from the first battery pack 44 and / or the second battery pack 46 to charge another energy storage system (e.g., vehicle-to-vehicle (V2V) and / or vehicle-to-all (V2X) charging). The charging system contains one or more charging modules.For example, a first on-board charging module (OBCM) 52 is electrically connected to a charging port 54 for charging to and from an AC system or device, such as a utility AC power supply. A second OBCM 53 may be included for DC charging (e.g., DC fast charging or DCFC).

[0021] In one embodiment, the switching system includes a first switching device 60 that selectively connects the first battery pack 44 to the front inverter 24, the left rear inverter 34L, and the right rear inverter 34R, and a second switching device 62 that selectively connects the second battery pack 46 to the front inverter 24, the left rear inverter 34L, and the right rear inverter 34R. The switching system also includes a third switching device 64 (also referred to as a "battery switching device") for selectively connecting the first battery pack 44 to the second battery pack 46 in series.

[0022] Any number of different controllers may be used to control functions of the battery system 40, the switching system, and the drive units. A controller includes any suitable processing device or processing unit and may utilize an existing controller such as a drive system controller, a RESS controller, and / or controllers within the drive system. For example, a controller 65 may be included to control switching and drive control operations, as discussed herein.

[0023] The vehicle 10 also includes a computer system 55 that includes one or more processing devices 56 and a user interface 58. The computer system 55 can communicate with the charging system controller, e.g., to provide instructions in response to user input. The various processing devices, modules, and units can communicate with each other using a communication device or system, such as a controller area network (CAN) or a transmission control protocol (TCP) bus.

[0024] As illustrated herein, vehicle 10 is an electric vehicle. In an alternative embodiment, vehicle 10 may be an internal combustion engine vehicle, a hybrid vehicle, etc.

[0025] Fig. 2 shows a side view of a battery pack 200 of the vehicle 10 in an illustrative embodiment. The battery pack 200 includes a housing 202 and one or more battery cells 204 within the housing 202 to provide power to the vehicle 10. Located on a bottom surface 208 of the housing 202 is a vent assembly 206 that allows aqueous fluids and gases (such as water, coolant, electrolytic fluids, and any fluids containing waste products from the operation of the one or more battery cells 204) to be vented from the housing 202. The vent assembly 206 includes a first portion 210 disposed within the housing 202 and a second portion 212 disposed outside the housing 202. The first portion 210 includes one or more inlets 214, and the second portion 212 includes one or more outlets 216.A fluid path within the vent assembly 206 connects the one or more inlets 214 of the first section 210 to the one or more outlets 216 of the second section 212, as shown in FIG. Fig. 3 is shown.

[0026] Fig. 3 shows a cross-sectional view 300 of the vent assembly 206 in an illustrative embodiment. The fluid path 302 shown connects the one or more inlets 214 of the first section 210 to the one or more outlets 216 of the second section 212. A vent valve 304 is disposed in the fluid path 302 within the second section 212. The vent valve 304 can be opened and closed to allow a fluid, such as an aqueous fluid, to flow through the fluid path 302 and out of the battery pack 200. The vent valve 304 controls the venting of the fluid during normal operation of the battery pack 200 (i.e., when the battery is not experiencing a thermal runaway event).

[0027] The first section 210 includes a chamber 306 on one side of the fluid path 302. As in Fig. 3, the chamber 306 is located above the one or more inlets 214. The chamber 306 includes a shutter 308 that can be moved from a first position (i.e., retracted within the chamber 306 and outside the fluid path 302) to a second position (i.e., extended into the fluid path). In the second position, the shutter 308 blocks the one or more inlets 214 and prevents any fluid from flowing through the fluid path 302. A biasing device 310, such as a spring, applies a biasing force to the shutter 308 toward the fluid path 302. The shutter 308 is held in the first position by a retainer that provides a resistive force to the biasing force of the biasing device 310.

[0028] According to one embodiment, the retention device is an adhesive material 312 that adheres to a side or perimeter of the closure 308 and to an interior surface 314 of the chamber 306. The adhesive material 312 retains the closure 308 within the chamber 306 until an environmental parameter exceeds a threshold. According to one embodiment, the adhesive material 312 is a temperature-sensitive material that loses its adhesive ability when a temperature of the adhesive material exceeds a temperature threshold. The temperature threshold corresponds to a temperature indicative of a thermal runaway event. When a thermal runaway event occurs, the temperature of the adhesive material exceeds the temperature threshold, and the adhesive material releases the closure 308 from the interior surface 314.The preload device 310 then pushes the closure 308 into the fluid path 302, thereby closing the fluid path 302 and preventing or reducing inadvertent venting from the battery pack 200.

[0029] According to another embodiment, the adhesive material 312 is pressure-sensitive and loses its adhesiveness when the pressure within the battery pack 200 exceeds a pressure threshold. The pressure threshold corresponds to a pressure indicative of a thermal runaway event. When a thermal runaway event occurs, the pressure within the housing 202 exceeds the pressure threshold of the adhesive material 312, and the adhesive material releases the closure 308 from the interior surface 314. The preload device 310 then forces the closure 308 into the fluid path 302.

[0030] Fig. 4 shows a cross-sectional view 400 of the vent assembly 206 with the closure 308 in the second position. Fig. 3 extends into the fluid path 302 and blocks the one or more inlets 214, thereby preventing inadvertent venting from the battery pack 200 through the vent assembly 206.

[0031] Fig. 5 shows a cross-sectional view 500 of the vent assembly 206 in another embodiment. The retention device is a shear device 402, such as a shear pin or shear screw, that extends into a groove in one side of the closure 308 and a recess in the wall of the chamber to secure the closure within the chamber in the first position. According to one embodiment, the shear device 402 may be temperature sensitive. When a temperature of the shear device 402 exceeds a selected threshold, the shear device may melt, weaken, or crack, causing the closure 308 to detach from the inner surface 314 of the chamber 306. According to an alternative embodiment, the shear device 402 may be a pressure-sensitive device that may break or crack when pressure on the shear device exceeds a pressure threshold, causing the closure 308 to detach from the inner surface 314 of the chamber 306.The preload device 310 then pushes the closure 308 into the second position in the fluid path 302, thereby closing the fluid path 302 and preventing or reducing inadvertent venting from the battery pack 200.

[0032] Fig. 6 shows a cross-sectional view 600 of the vent assembly 206 in another embodiment. The retaining device includes a retractable pin 602 extending into a groove in one side of the closure 308 and a solenoid 604 located in the wall of the chamber to secure the closure in the chamber 306 at the first position. When the solenoid 604 is activated, it can retract the retractable pin 602 from the groove of the closure 308, thereby allowing the biasing device 310 to urge the closure into the second position in the fluid path 302. A sensor 606 measures at least one of a temperature and a pressure and activates the solenoid when the temperature and / or pressure exceeds a threshold to release the closure 308. The sensor 606 can be disposed at the one or more inputs 214 or at another suitable location.

[0033] Fig.7 shows a cross-sectional view 700 of the vent assembly 206 in another embodiment. The retention device is a flap 702 located below the closure 308 and retaining the closure in the chamber 306 in the first position. A sensor 704 measures at least one of a temperature and a pressure and activates the flap 702 to release the closure 308 when the temperature and / or pressure exceeds a threshold for releasing the closure 308. The biasing device 310 can then urge the closure into the second position in the fluid path 302.

[0034] Although other embodiments have explained that the preloading device 310 provides the force to move the closure 308 from the first position to the second position, once the closure 308 is released from the inner surface 314, it may fall into the second position due to the gravity of the closure's mass without the use of a preloading device. Additionally, the preloading device may be replaced by an additional mass placed on the closure 308.

[0035] The terms "a" and "an" do not imply a limitation of number, but rather denote the presence of at least one of the referenced elements. The term "or" means "and / or" unless clearly indicated otherwise by context. A reference throughout the application text to "an aspect" means that a particular element (e.g., a feature, structure, step, or property) described in connection with the aspect is included in at least one aspect described herein and may or may not be present in further aspects. In addition, it is to be understood that the described elements in the various aspects may be combined in any suitable manner.

[0036] When an element, such as a layer, film, region, or substrate, is referred to as "on" another element, it may be directly adjacent to the other element or may also have intervening elements present. In contrast, when an element is referred to as "directly adjacent" to another element, no intervening elements are present.

[0037] Unless otherwise specified herein, all examination standards shall be the most recent standard in force as of the filing date of this application or, if priority is claimed, the filing date of the earliest priority application in which the examination standard appears.

[0038] Unless otherwise defined, 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 belongs.

[0039] While the above disclosure has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes may be made and equivalents may be substituted for elements without departing from the scope thereof. Additionally, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from its essential scope. Therefore, it is intended that the present disclosure not be limited to the particular embodiments disclosed, but will include all embodiments falling within its scope.

Claims

[1] Drainage arrangement for a battery comprising: a fluid path for the flow of a fluid from the battery; a closure disposed in a first position outside the fluid path; a holding device that holds the closure in the first position, the holding device being configured to release the closure when an environmental parameter of the battery exceeds a threshold; and a preloading device that preloads the closure toward a second position in the fluid path. [2] The vent assembly of claim 1, wherein the retaining device releases the closure when either: (i) a temperature at the vent assembly is at or above a temperature threshold; or (ii) a pressure at the vent assembly is at or above a pressure threshold. [3] The vent assembly of claim 1, wherein the retaining device comprises: (i) an adhesive material; (ii) a shearing device; (iii) a retractable pin; or (iv) a flap. [4] The vent assembly of claim 1, wherein the biasing device comprises: (i) a spring in a chamber on one side of the fluid path; (ii) an additional mass attached to the closure; or (iii) a mass of the closure. [5] The vent assembly of claim 1, wherein the fluid path extends between an inlet within the housing of the battery and an outlet outside the housing, and the first position is in a chamber to one side of the inlet and the second position is in front of the inlet. [6] Battery for a vehicle, comprising: a housing; a vent assembly having a first portion within the housing and a second portion outside the housing; a fluid path through the drain assembly for the flow of a fluid from the battery; a closure disposed in a first position outside the fluid path; a holding device that holds the closure in the first position, the holding device being configured to release the closure when an environmental parameter of the battery exceeds a threshold; and a preloading device that preloads the closure toward a second position in the fluid path. [7] The battery of claim 6, wherein the retaining device releases the closure when either: (i) a temperature at the vent assembly is at or above a temperature threshold; or (ii) a pressure at the vent assembly is at or above a pressure threshold. [8] The battery of claim 6, wherein the holding device comprises: (i) an adhesive material; (ii) a shearing device; (iii) a retractable pin; or (iv) a flap. [9] A battery according to claim 6, wherein the preloading device comprises: (i) a spring within a chamber on one side of the fluid path; (ii) an additional mass attached to the closure; or (iii) a mass of the closure. [10] A battery according to claim 6, wherein the fluid path extends between an inlet in the first section and an outlet in the second section, and the first position is in a chamber of the first section on one side of the inlet and the second position is in front of the inlet.

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