High voltage battery drain valve thermal runaway plug

Abstract

A vehicle includes a battery and a discharge assembly for the battery. The battery includes a housing and a drain assembly having a first section within the housing and a second section outside the housing. A fluid path passes through the drain assembly to flow fluid from the battery. The plug is disposed at a first location outside the fluid path. The retaining device retains the plug in the first position. The holding device is configured to release the plug when an environmental parameter of the battery exceeds a threshold. A biasing device biases the plug toward a second position in the fluid path.

Description

Technical Field

[0001] The subject disclosure relates to preventing thermal runaway in batteries used in vehicles, and in particular, to a temperature controlled drain valve for a battery. Background Art

[0002] Batteries used in vehicles may include a drain valve that allows fluid to be discharged from the battery. Thermal runaway events sometimes occur in these batteries. During a thermal runaway event, the drain valve may become an unintended path for gases to be discharged from the battery, which may accelerate thermal runaway. Therefore, it is desirable to provide a drain valve that prevents accidental venting. Summary of the invention

[0003] In one exemplary embodiment, a vent assembly for a battery is disclosed. The vent assembly includes a fluid path for flowing a fluid from the battery, a plug disposed at a first position outside the fluid path, a retaining device for retaining the plug in the first position, wherein the retaining device is configured to release the plug when an environmental parameter of the battery exceeds a threshold value, and a biasing device for biasing the plug toward a second position in the fluid path.

[0004] In addition to one or more features described herein, the retaining device releases the plug when the temperature at the discharge assembly is at or above a temperature threshold and the pressure at the discharge assembly is at or above one of a pressure threshold. The retaining device is one of an adhesive material, a shearing device, a retractable pin, and a trap door. The biasing device is one of a spring located in a chamber on one side of the fluid path, an additional mass placed on the plug, and the mass of the plug. 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 on one side of the inlet and the second position is in front of the inlet. The discharge assembly also includes a discharge valve in the fluid path at the outlet. The fluid is one of an aqueous fluid, a gas, a coolant, and an electrolyte.

[0005] In another exemplary embodiment, a battery for a vehicle is disclosed. The battery includes a housing, a vent assembly having a first section within the housing and a second section outside the housing, a fluid path through the vent assembly for flowing a fluid from the battery, a plug disposed at a first position outside the fluid path, a retaining device to retain the plug in the first position, wherein the retaining device is configured to release the plug when an environmental parameter of the battery exceeds a threshold value, and a biasing device to bias the plug toward a second position in the fluid path.

[0006] In addition to one or more features described herein, the retaining device releases the plug when the temperature at the discharge assembly is at or above a temperature threshold and the pressure at the discharge assembly is at or above one of a pressure threshold. The retaining device is one of an adhesive material, a shearing device, a retractable pin, and a trap door. The biasing device is one of a spring located in a chamber on one side of the fluid path, an additional mass placed on the plug, and the mass of the plug. 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 in the first section on one side of the inlet, and the second position is in front of the inlet. The battery also includes a discharge valve in the fluid path at the outlet. The fluid is one of an aqueous fluid, a gas, a coolant, and an electrolyte.

[0007] In another exemplary embodiment, a vehicle is disclosed. The vehicle includes a battery having a housing and a drain assembly. The drain assembly has a first section within the housing and a second section outside the housing, a fluid path through the drain assembly for flowing fluid from the battery, a plug disposed at a first position outside the fluid path, a retaining device to retain the plug in the first position, wherein the retaining device is configured to release the plug when an environmental parameter of the battery exceeds a threshold, and a biasing device to bias the plug toward a second position in the fluid path.

[0008] In addition to one or more features described herein, the retaining device releases the plug when the temperature at the exhaust assembly is at or above a temperature threshold and the pressure at the exhaust assembly is at or above one of a pressure threshold. The retaining device is one of an adhesive material, a shearing device, a retractable pin, and a trap door. The biasing device is one of a spring located in a chamber on one side of the fluid path, an additional mass placed on the plug, and the mass of the plug. The fluid path extends between an inlet in the first section and an outlet in the second section, and the first position is in the chamber of the first section on one side of the inlet, and the second position is in front of the inlet. The vehicle also includes a discharge valve in the fluid path at the outlet.

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

[0010] Other features, advantages and details appear, by way of example only, in the following detailed description, which refers to the accompanying drawings, in which:

[0011] Figure 1 An embodiment of a vehicle is shown that includes a body at least partially defining a passenger compartment;

[0012] Figure 2 shows a side view of a battery pack of a vehicle in an illustrative embodiment;

[0013] Figure 3 shows a cross-sectional view of a drain assembly in an illustrative embodiment;

[0014] Figure 4 showing a cross-sectional view of the drain assembly with the plug in a second position;

[0015] Figure 5 shows a cross-sectional view of a discharge assembly in another embodiment;

[0016] Figure 6 A cross-sectional view showing a drain assembly in another embodiment; and

[0017] Figure 7 A cross-sectional view of a drain assembly in another embodiment is shown. DETAILED DESCRIPTION

[0018] 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 numerals indicate the same or corresponding parts and features.

[0019] According to an exemplary embodiment, Figure 1 An embodiment of a vehicle 10 is shown that includes a body 12 that at least partially defines an occupant compartment 14. The body 12 also supports various vehicle subsystems, including a propulsion system 16, as well as other subsystems for supporting the functions of the propulsion system 16 and other vehicle components, such as a braking subsystem, a suspension system, a steering subsystem, etc.

[0020] The vehicle 10 may be an electric vehicle (EV), a hybrid vehicle, or any other vehicle. In one embodiment, the vehicle 10 is an electric vehicle including a plurality of motors and / or drive systems. Any number of drive units may be included, such as one or more drive units for applying torque to the 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"), etc.

[0021] For example, the propulsion system 16 is a multi-drive system that includes a front drive unit 20 for driving the front wheels and a rear drive unit for driving the 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. The left rear drive unit 30L includes a left rear electric motor 32L and a left rear inverter 34L. The 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., a power inverter unit or PIM) each convert the direct current (DC) power from the high voltage (HV) battery system 40 into a multi-phase (e.g., two-phase, three-phase, six-phase, etc.) alternating current (AC) power to drive the front electric motor 22, the left rear electric motor 32L, and the right rear electric motor 32R.

[0022] like Figure 1 As shown, the drive system features a single electric motor. However, embodiments are not limited thereto. For example, instead of a single motor, multiple drives may be provided by a single machine having physically separate sets of windings.

[0023] Also like Figure 1 As shown, the drive system is 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, the embodiments are not limited in this regard, as there may be any number of drive systems and / or motors at various locations (e.g., a motor driving each wheel, dual motors for each axle, etc.). In addition, the embodiments are not limited to dual drive systems, as the embodiments may be used with vehicles having any number of motors and / or power inverters.

[0024] In the propulsion system 16, the front drive unit 20, the left rear drive unit 30L, and the right rear drive unit 30R are electrically connected to a 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), heaters, cooling systems, etc. The battery system 40 may be configured as a rechargeable energy storage system (RESS).

[0025] In one embodiment, the battery system 40 includes a plurality of individual battery assemblies, each of which can be independently charged and can be used to independently power one or more drive 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 plurality of individual battery cells (not shown). In various embodiments, one or more battery packs may include MODACS (Multi-Output Dynamically Adjustable Capacity) batteries, as described herein with respect to Figure 2-4 described.

[0026] 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 a three-phase motor winding. However, the embodiments described herein are not limited thereto. For example, the motor may be any multi-phase machine supplied by a multi-phase inverter, and the drive unit may be implemented using a single machine having independent sets of windings.

[0027] The battery system 40 and / or the propulsion system 16 include a switch system having various switch 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 switch device can also be operated to selectively connect the first battery pack 44 and the second battery pack 46 to the charging system. The charging system can be used to charge the first battery pack 44 and the second battery pack 46, and / or 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-everything (V2X) charging). The charging system includes one or more charging modules. For example, a first onboard charging module (OBCM) 52 is electrically connected to a charging port 54 for charging and charging from an AC system or device (such as a public AC power supply). A second OBCM 53 may be included for DC charging (e.g., DC fast charging or DCFC).

[0028] In one embodiment, the switch system includes a first switch device 60 and a second switch device 62, wherein the first switch device 60 selectively connects the first battery pack 44 to the front inverter 24, the left rear inverter 34L, and the right rear inverter 34R, and the second switch device 62 selectively connects the second battery pack 46 to the front inverter 24, the left rear inverter 34L, and the right rear inverter 34R. The switch system also includes a third switch device 64 (also referred to as a "battery switch device") for selectively connecting the first battery pack 44 in series to the second battery pack 46.

[0029] Any of a variety of controllers may be used to control the functions of the battery system 40, the switch system, and the drive unit. The controller includes any suitable processing device or unit, and an existing controller such as a drive system controller, a RESS controller, and / or a controller in a drive system may be used. For example, a controller 65 may be included to control the switch and drive control operations as discussed herein.

[0030] The vehicle 10 also includes a computer system 55 including one or more processing devices 56 and a user interface 58. The computer system 55 can communicate with the charging system controller, for example, to provide commands thereto in response to user input. The various processing devices, modules, and units can communicate with each other via a communication device or system, such as a controller area network (CAN) or a transmission control protocol (TCP) bus.

[0031] As shown here, the vehicle 10 is an electric vehicle. In alternative embodiments, the vehicle 10 may be an internal combustion engine vehicle, a hybrid vehicle, or the like.

[0032] Figure 2 A side view of a battery pack 200 of a vehicle 10 in an illustrative embodiment is shown. The battery pack 200 includes a housing 202 and one or more battery cells 204 within the housing 202 for providing power to the vehicle 10. A drain assembly 206 is located at a bottom surface 208 of the housing 202 and allows aqueous fluids and gases (such as water, coolant, electrolytic fluid, and any fluid containing waste from the operation of the one or more battery cells 204) to drain from the housing 202. The drain assembly 206 includes a first section 210 disposed inside the housing 202 and a second section 212 disposed outside the housing 202. The first section 210 includes one or more inlets 214, and the second section 212 includes one or more outlets 216. A fluid path within the drain 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. Figure 3 shown.

[0033] Figure 3 A cross-sectional view 300 of the drain assembly 206 in an illustrative embodiment is shown. A fluid path 302 is shown connecting one or more inlets 214 of the first section 210 to one or more outlets 216 of the second section 212. A drain valve 304 is disposed in the fluid path 302 within the second section 212. The drain 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 drain valve 304 controls fluid discharge during normal operation of the battery pack 200 (i.e., when the battery is not experiencing a thermal runaway event).

[0034] The first section 210 includes a chamber 306 on one side of the fluid path 302. Figure 3 As shown, the chamber 306 is located above the one or more inlets 214. The chamber 306 includes a plug 308 that can be moved from a first position (i.e., retracted into 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 plug 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 on the plug 308 in the direction of the fluid path 302. The plug 308 is retained in the first position by a retaining device that provides resistance against the biasing force of the biasing device 310.

[0035] In one embodiment, the retaining device is an adhesive material 312 that adheres to the sides or circumference of the plug 308 and to the inner surface 314 of the chamber 306. The adhesive material 312 retains the plug 308 in the chamber 306 until the environmental parameter exceeds a threshold. In one embodiment, the adhesive material 312 is a temperature sensitive material that loses its adhesive ability when the temperature of the adhesive material exceeds a temperature threshold. The temperature threshold corresponds to a temperature indicating 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 plug 308 from the inner surface 314. The biasing device 310 then pushes the plug 308 into the fluid path 302, thereby closing the fluid path 302 and preventing or reducing unintentional venting from the battery pack 200.

[0036] In another embodiment, the adhesive material 312 is pressure sensitive and loses its adhesive ability when the pressure within the battery pack 200 exceeds a pressure threshold. The pressure threshold corresponds to a pressure indicating 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 plug 308 from the inner surface 314. The biasing device 310 then pushes the plug 308 into the fluid path 302.

[0037] Figure 4 A cross-sectional view 400 of the vent assembly 206 is shown with the plug 308 in the second position. The plug 308 is shown extending into the fluid path 302 ( Figure 3 ), and blocks one or more inlets 214, thereby preventing unintentional exhaust from the battery pack 200 through the exhaust assembly 206.

[0038] Figure 5A cross-sectional view 500 of the vent assembly 206 in another embodiment is shown. The retaining device is a shear device 402, such as a shear pin or a shear screw, which extends into a groove in one side of the plug 308 and a recess in the wall of the chamber to secure the plug at a first position in the chamber. In an embodiment, the shear device 402 can be temperature sensitive. When the temperature of the shear device 402 exceeds a selected threshold, the shear device can melt, weaken, or rupture, thereby releasing the plug 308 from the inner surface 314 of the chamber 306. In an alternative embodiment, the shear device 402 can be a pressure sensitive device that can break or rupture when the pressure on the shear device exceeds a pressure threshold, thereby releasing the plug 308 from the inner surface 314 of the chamber 306. The biasing device 310 then pushes the plug 308 into a second position in the fluid path 302, thereby closing the fluid path 302 and preventing or reducing unintentional venting from the battery pack 200.

[0039] Figure 6 A cross-sectional view 600 of the vent assembly 206 in another embodiment is shown. The retaining means is a retractable pin 602 extending into a groove in one side of the plug 308 and a solenoid 604 located in the wall of the chamber to secure the plug in a first position in the chamber 306. When activated, the solenoid 604 can retract the retractable pin 602 from the groove of the plug 308, thereby allowing the biasing means 310 to push the plug into a second position in the fluid path 302. The sensor 606 measures at least one of temperature and pressure, and activates the solenoid to release the plug 308 when the temperature and / or pressure exceeds a threshold. The sensor 606 can be located at one or more of the inlets 214 or at other suitable locations.

[0040] Figure 7 A cross-sectional view 700 of the vent assembly 206 in another embodiment is shown. The retaining device is a trap door 702 that is located below the plug 308 and retains the plug in a first position in the chamber 306. The sensor 704 measures at least one of temperature and pressure, and when the temperature and / or pressure exceeds a threshold to release the plug 308, the trap door 702 is activated to release the plug 308. The biasing device 310 can then push the plug into a second position in the fluid path 302.

[0041] Although biasing device 310 has been discussed as providing a force for moving plug 308 from the first position to the second position, in other embodiments, once plug 308 is released from inner surface 314, plug 308 may fall into the second position due to the force of gravity on the mass of the plug without using a biasing device. In addition, the biasing device may be replaced by an additional mass placed on top of plug 308.

[0042] The terms "a" and "an" do not indicate a limitation of quantity, but rather indicate the presence of at least one of the referenced item. Unless the context clearly indicates otherwise, the term "or" means "and / or". References to "aspects" throughout the specification mean that a particular element (e.g., a feature, structure, step, or characteristic) described in conjunction with that aspect is included in at least one aspect described herein, and may or may not be present in other aspects. In addition, it should be understood that the described elements may be combined in any suitable manner in the various aspects.

[0043] 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 intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.

[0044] Unless stated to the contrary herein, all test standards are the most current standards in effect as of the filing date of this application or, if priority is claimed, the filing date of the earliest priority application in which the test standards appear.

[0045] Unless defined otherwise, 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.

[0046] Although the above disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted for its elements without departing from its scope. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the disclosure without departing from the basic scope of the disclosure. Therefore, it is intended that the disclosure is not limited to the specific embodiments disclosed, but will include all embodiments falling within its scope.

Claims

1. A discharge assembly for a battery, comprising: a fluid path for flowing a fluid from the battery; a plug disposed at a first position outside of the fluid path; a retaining device that retains the plug in a first position, wherein the retaining device is configured to release the plug when an environmental parameter of the battery exceeds a threshold value; as well as A biasing device biases the plug toward a second position in the fluid path.

2. An exhaust assembly according to claim 1, wherein the retaining device releases the plug when one of the following: (i) the temperature at the exhaust assembly is at or above a temperature threshold; and (ii) the pressure at the exhaust assembly is at or above a pressure threshold.

3. The discharge assembly of claim 1, wherein the retaining device is one of: (i) an adhesive material; (ii) a shear device; (iii) a retractable pin; and (iv) a trap door.

4. The exhaust assembly of claim 1, wherein the biasing device is one of: (i) a spring within a chamber on one side of the fluid path; (ii) an additional mass placed on the plug; and (iii) the mass of the plug.

5. The vent assembly of claim 1, wherein the fluid path extends between an inlet within a housing of the battery and an outlet outside the housing, and a first position is in a chamber to one side of the inlet and a second position is in front of the inlet.

6. A battery for a vehicle, comprising: case; an exhaust assembly having a first section within the housing and a second section external to the housing; a fluid path through the vent assembly for flowing fluid from the battery; a plug disposed at a first position outside of the fluid path; a retaining device that retains the plug in a first position, wherein the retaining device is configured to release the plug when an environmental parameter of the battery exceeds a threshold value; as well as A biasing device biases the plug toward a second position in the fluid path.

7. The battery of claim 6, wherein the retaining device releases the plug when one of: (i) the temperature at the vent assembly is at or above a temperature threshold; and (ii) the pressure at the vent assembly is at or above a pressure threshold.

8. The battery of claim 6, wherein the retaining device is one of: (i) an adhesive material; (ii) a shear device; (iii) a retractable pin; and (iv) a trap door.

9. The battery of claim 6, wherein the biasing device is one of: (i) a spring within a chamber on one side of the fluid path; (ii) an additional mass placed on the plug; and (iii) the mass of the plug.

10. The battery of 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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