Traction battery pack decompression device with ratchet mechanism

Abstract

The invention provides a traction battery pack decompression device with a ratchet mechanism. A traction battery assembly includes a housing assembly having an interior region; and a pressure reducing device having a valve member, the valve member being movable from a closed position to an unlocked-released position and from the unlocked-released position to a locked-released position. The valve member in the closed position blocks flow from the interior region through the decompression device. The valve member in the unlocked-released position allows flow from the interior region. The valve member in the locked-released position allows flow from the interior region. A ratchet mechanism holds the valve member in the lock-release position.

Description

Technical Field

[0001] The present disclosure relates generally to electrified vehicle traction battery packs and, more particularly, to a pressure relief device for a traction battery pack. Background Art

[0002] A high voltage traction battery pack typically supplies power to the electric motor and other electrical loads of an electrified vehicle. The traction battery pack includes a plurality of battery cells and various other battery internal components housed inside a housing assembly for supporting the electric propulsion of the vehicle. The housing assembly is sealed but vented to help mitigate pressure imbalances and prevent moisture from accumulating within the interior of the battery pack. Summary of the invention

[0003] In some aspects, the technology described herein relates to a traction battery assembly including: a housing assembly having an interior region; a pressure relief device having a valve member movable from a closed position to an unlocked-release position and movable from the unlocked-release position to a locked-release position, the valve member in the closed position blocking flow through the pressure relief device from the interior region, the valve member in the unlocked-release position allowing flow from the interior region, and the valve member in the locked-release position allowing flow from the interior region; and a ratchet mechanism retaining the valve member in the locked-release position.

[0004] In some aspects, the technology described herein relates to a traction battery assembly in which the valve member freely moves back and forth between the closed position and the unlocked-release position.

[0005] In some aspects, the technology described herein relates to a traction battery assembly wherein the valve member in the locked-release position permits more flow from the interior region than the valve member in the unlocked-release position.

[0006] In some aspects, the technology described herein relates to a traction battery assembly that also includes a biasing device that biases the pressure relief device to the closed position.

[0007] In some aspects, the technology described herein relates to a traction battery assembly wherein the biasing member is a coil spring.

[0008] In some aspects, the technology described herein relates to a traction battery assembly wherein the ratchet mechanism includes at least one tooth.

[0009] In some aspects, the technology described herein relates to a traction battery assembly wherein the ratchet mechanism is configured to block movement of the valve member from the locked-release position back to the unlocked-release position when the ratchet mechanism retains the valve member in the locked-release position.

[0010] In some aspects, the technology described herein relates to a traction battery assembly wherein the ratchet mechanism is configured to retain the valve member in a first lock-release position that allows a first amount of flow from the interior region, wherein the ratchet mechanism is further configured to retain the valve member in a second lock-release position that allows a second amount of flow from the interior region, the second flow rate being greater than the first flow rate.

[0011] In some aspects, the technology described herein relates to a traction battery assembly wherein the valve member translates along an axis when moving from the closed position to the locked-release position, the ratchet mechanism has a first plurality of teeth distributed circumferentially about the axis that retains the valve member in the first locked-release position, and the ratchet mechanism has a second plurality of teeth distributed circumferentially about the axis that retains the valve member in the second locked-release position.

[0012] In some aspects, the technology described herein relates to a traction battery assembly, which also includes a plurality of fingers of the pressure relief device, the plurality of fingers distributed circumferentially about the valve member, each of the fingers within the plurality of fingers including at least one tooth of the teeth in the first plurality of teeth and at least one tooth of the teeth in the second plurality of teeth.

[0013] In some aspects, the technology described herein relates to a traction battery assembly that includes a plurality of battery arrays housed inside a housing assembly.

[0014] In some aspects, the technology described herein relates to a traction battery assembly wherein the valve member is configured to move from the closed position to the unlocked-release position in response to pressure within the interior region exceeding pressure outside the interior region by a first amount, wherein the valve member is configured to move from the unlocked-release position to the locked-release position in response to the pressure within the interior region exceeding the pressure outside the interior region by a second amount that is greater than the first amount.

[0015] In some aspects, the technology described herein relates to a traction battery pack flow control method, the traction battery pack flow control method comprising: in response to the pressure within the interior area of ​​the housing assembly exceeding the pressure outside the interior area by a first amount, transitioning a valve member of a pressure relief device from a closed position to an unlocked-released position; and in response to the pressure within the interior area of ​​the housing assembly exceeding the pressure outside the interior area by a second amount greater than the first amount, transitioning the valve member to a locked-released position.

[0016] In some aspects, the technology described herein relates to a traction battery flow control method that also includes retaining the valve member in the locked-release position using a ratchet mechanism.

[0017] In some aspects, the technology described herein relates to a traction battery flow control method that also includes retaining the valve member in the locked-release position using at least one tooth.

[0018] In some aspects, the technology described herein relates to a traction battery pack flow control method wherein maintaining the valve member in the locked-release position blocks movement of the valve member back to the unlocked-release position or the closed position.

[0019] In some aspects, the technology described herein relates to a traction battery pack flow control method wherein the pressure relief device allows more flow from the interior region when the valve member is in the locked-release position than when the valve member is in the unlocked-release position.

[0020] In some aspects, the technology described herein relates to a traction battery pack flow control method that also includes biasing the valve member toward the closed position.

[0021] In some aspects, the technology described herein relates to a traction battery flow control method, wherein the lock-release position is a first lock-release position, and the traction battery flow control method further includes: in response to the pressure within the interior region of the housing assembly exceeding the pressure outside the interior region by a third amount that is greater than the second amount, transitioning the valve member to a second lock-release position.

[0022] In some aspects, the technology described herein relates to a traction battery pack flow control method wherein the pressure relief device allows more flow from the interior region when the valve member is in the second lock-release position than when the valve member is in the first lock-release position.

[0023] The embodiments, examples and alternatives of the preceding paragraphs, claims or the following description and drawings (including any of their various aspects or corresponding individual features) may be adopted independently or in any combination. Features described in conjunction with one embodiment apply to all embodiments, unless such features are incompatible. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The various features and advantages of the present disclosure will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.

[0025] Figure 1 An electrified vehicle is schematically shown.

[0026] Figure 2 Is from Figure 1 A perspective view of a battery pack for an electrified vehicle.

[0027] Figure 3 is a perspective view of another battery pack according to another exemplary embodiment.

[0028] Figure 4A and Figure 4B Shown in closed position Figure 2 Perspective and cross-sectional views of a decompression device for a traction battery pack.

[0029] Figure 5A and Figure 5B Shown in unlocked-release position Figure 2 Perspective and cross-sectional views of a pressure relief device.

[0030] Fig. 6A and Figure 6B Shown in a first locked-release position Figure 2 Perspective and cross-sectional views of a pressure relief device.

[0031] Fig. 7A and Figure 7B Shown in a second locked-release position Figure 2 Perspective and cross-sectional views of a pressure relief device. DETAILED DESCRIPTION

[0032] The present disclosure details an exemplary traction battery pack design for use in an electrified vehicle. An exemplary traction battery pack may include a housing assembly that establishes an interior, and a battery array housed within the interior. To balance the pressure inside and outside the battery pack during normal battery operation, a pressure relief device may be disposed within the walls of the housing assembly. These and other features are discussed in more detail in the following paragraphs of this detailed description.

[0033] Figure 1An electrified vehicle 10 is schematically shown. The electrified vehicle 10 may include any type of electrified powertrain. In one embodiment, the electrified vehicle 10 is a battery electric vehicle (BEV). However, the concepts described herein are not limited to BEVs and may be extended to other electrified vehicles, including but not limited to hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles, etc. Therefore, although not specifically shown in the exemplary embodiment, the electrified vehicle 10 may be equipped with an internal combustion engine, which may be employed alone or in combination with other power sources to propel the electrified vehicle 10.

[0034] In the illustrated embodiment, the electrified vehicle 10 is a sport utility vehicle (SUV). However, the electrified vehicle 10 may alternatively be a sedan, a van, a pickup truck, or any other vehicle configuration. Although specific component relationships are shown in the drawings of the present disclosure, the drawings are not intended to limit the present disclosure. The placement and orientation of the various components of the electrified vehicle 10 are shown schematically and may vary within the scope of the present disclosure. In addition, the various drawings attached to the present disclosure are not necessarily drawn to scale, and some features may be exaggerated or minimized to emphasize certain details of a particular component or system.

[0035] In the illustrated embodiment, the electrified vehicle 10 is a pure electric vehicle that is propelled solely by electricity, such as by one or more electric machines 12, without assistance from an internal combustion engine. The electric machines 12 may operate as electric motors, generators, or both. The electric machines 12 receive electricity and may convert the electricity into torque for driving one or more wheels 14 of the electrified vehicle 10.

[0036] The voltage bus 16 may electrically couple the electric machine 12 to a traction battery pack 18. The traction battery pack 18 is an exemplary electrified vehicle battery. The traction battery pack 18 may be a high voltage traction battery pack that includes one or more battery arrays 20 (i.e., battery assemblies, or groupings of rechargeable battery cells 26) capable of outputting electrical power to power the electric machine 12 and / or other electrical loads of the electrified vehicle 10. Other types of energy storage devices and / or output devices may alternatively or additionally be used to electrically power the electrified vehicle 10.

[0037] The battery cells 26 may be stacked side-by-side along a stacking axis to form a grouping of battery cells 26 (sometimes referred to as a "battery cell stack"). Figure 1 In the highly schematic depiction of FIG. 2 , the battery cells 26 are stacked in a direction into the drawing page to make up each battery array 20 , and thus the battery array 20 extends in a cross-vehicle direction. However, other configurations may also be possible.

[0038] The total number of battery arrays 20 and battery cells 26 provided within the traction battery pack 18 is not intended to limit the present disclosure. In one embodiment, the battery cells 26 of each battery array 20 are prismatic lithium-ion cells. However, within the scope of the present disclosure, battery cells having other geometries (cylindrical, pouch, etc.), other chemistries (nickel metal hydride, lead acid, etc.), or both may alternatively be utilized.

[0039] The traction battery pack 18 may be secured to an underbody 22 of the electrified vehicle 10 . However, the traction battery pack 18 may be located elsewhere on the electrified vehicle 10 within the scope of the present disclosure.

[0040] The housing assembly 24 houses the battery array 20 of the traction battery pack 18. The housing assembly 24 may be a sealed housing and may embody any size, shape, and configuration within the scope of the present disclosure.

[0041] In an exemplary embodiment, the housing assembly 24 includes a housing cover 28 and a housing tray 30. The housing cover 28 and the housing tray 30 may together establish an interior I for housing the battery array 20 and other battery internal components (e.g., bus electrical center, battery electronic control module, wiring, connectors, etc.) of the traction battery pack 18.

[0042] During assembly of the traction battery pack 18, the housing cover 28 may be secured to the housing tray 30 at an interface 32 therebetween. The interface 32 may substantially surround the interior I. In some implementations, mechanical fasteners 34 may be used to secure the housing cover 28 to the housing tray 30, although other fastening methods (adhesion, etc.) may also be suitable for this purpose.

[0043] Reference now Figure 2 , and continue to refer to Figure 1 , the traction battery pack 18 may include one or more pressure relief devices 36. Although two pressure relief devices 36 are shown, the traction battery pack 18 may include a greater or lesser number of such devices.

[0044] Each pressure relief device 36 can be disposed within a wall 38 of the housing assembly 24. In one embodiment, the wall 38 is a portion of the housing tray 30. In another embodiment, the wall 38 is a portion of the housing cover 28 (see FIG. Figure 3 ). However, the exact mounting location of each pressure relief device 36 may vary and is therefore not intended to limit the present disclosure.

[0045] The pressure relief devices 36 may be secured to the wall 38 in any manner. In the exemplary embodiment, each pressure relief device 36 is secured within the wall 38 via a twist-lock mount. However, the pressure relief devices 36 may alternatively or additionally be mounted via mechanical fasteners, cam locks, adhesives, etc.

[0046] The example pressure relief device includes a valve member 40 that can be Figure 4A and Figure 4B The closed position shown in the figure moves to Figure 5A and Figure 5B The unlocked-release position shown in Fig. 6A and Figure 6B The first locking-release position shown in FIG. Fig. 7A and Figure 7B The valve member 40 of the pressure relief device 36 is movable from the closed position in response to a pressure differential between the interior I of the housing assembly 24 and an area outside the housing assembly 24 .

[0047] The valve member 40 in the closed position blocks flow through the pressure relief device 36. The valve member 40 in the unlocked-released position allows a first amount of flow through the pressure relief device 36. The valve member 40 in the first locked-released position allows a second amount of flow through the pressure relief device 36. The second flow rate is greater than the first flow rate. The valve member 40 in the second locked-released position allows a third amount of flow through the pressure relief device 36. The third flow rate is greater than the second flow rate.

[0048] In addition to the valve member 40, the example pressure relief device 36 includes a housing 42 and a biasing member, here a spring 44. The housing 42 holds the valve member 40 and is fixed to the wall 38. The spring 44 biases the valve member 40 to Figure 4A and Figure 4B During normal operation, the valve member 40 remains in the closed position. Figure 4A and Figure 4B The closed position is shown in .

[0049] At times, the pressure within the interior I may increase relative to the pressure outside the interior I. The pressure differential between the interior I and the area outside the housing assembly 24 may cause the valve member 40 to move from the closed position.

[0050] For example, if the pressure within the interior I increases to, for example, 0.5 psi greater than the pressure outside the interior I, the pressure may overcome the spring bias and cause the valve member 40 to open. Figure 4A and Figure 4B The closed position moves to Figure 5A and Figure 5B In this position, some flow F can move from the interior I through the pressure relief device 36 to the area outside the interior I. This can help to balance the pressure between the interior I and the area outside the housing assembly 24. After the pressure is substantially equalized, the spring 44 moves the valve member 40 back to the Figure 4A and Figure 4BThe valve member 40 in the unlocked-released position is free to return to the closed position. If a relatively low pressure difference continues to exist, the valve member 40 can continue to move back and forth to relieve the pressure difference and balance the pressure inside the interior I with the pressure outside the interior I.

[0051] There may be some operating conditions where the pressure and thermal energy within the interior I increase rapidly, causing the pressure differential to be greater. For example, a battery thermal event may occur during an over-temperature, over-charge, or over-discharge condition of the battery cell 26, or during other battery cell conditions. During these conditions, battery venting byproducts may be released from one or more battery cells 26 of the battery array 20. This may cause the pressure within the interior I to increase rapidly and reach a pressure that is much higher than the pressure outside the traction battery pack 18. This significant difference between the pressure within the interior I and the area outside the interior I may cause the valve member 40 to be moved from the interior I to the outside of the traction battery pack 18. Figure 4A and Figure 4B The closed position pops outward, passing through Figure 5A and Figure 5B unlock-release position and reaches Fig. 6A and Figure 6B If the pressure difference is even higher, the pressure difference may cause the valve member 40 to protrude outwardly through Fig. 6A and Figure 6B The first locking-release position is reached Fig. 7A and Figure 7B The second locked-release position is shown in .

[0052] In this example, the housing 42 is equipped with a ratchet mechanism 46 that holds the valve member 40 in the first lock-release position or the second lock-release position. In this example, the ratchet mechanism 46 includes a first plurality of teeth 50 that protrude inwardly toward the valve member 40 from corresponding fingers 52 of the housing 42. The fingers 52 are distributed circumferentially around the valve member 40. The ratchet mechanism 46 additionally includes a second plurality of teeth 54 that protrude inwardly from the fingers 52. The second plurality of teeth 54 are spaced further from the interior I than the first plurality of teeth 50.

[0053] Other example ratchet mechanisms may include a second plurality of teeth 54 and only a first plurality of teeth 50, so that the valve member 40 can be moved to a single lock-release position. Still other ratchet mechanisms may include more than the first and second plurality of teeth, and the valve member 40 may be able to move to more than two lock-release positions.

[0054] When the valve member 40 is Figure 5A and Figure 5B The unlock-release position moves outward to Fig. 6A and Figure 6BWhen the valve member 40 is in the first locked-release position, a portion of the valve member 40 slides over the first plurality of teeth 50, thereby forcing the fingers 52 to yield slightly outwardly away from the valve member 40. After the valve member 40 has moved outwardly past the first plurality of teeth 50, the fingers 52 jump back inwardly toward the valve member 40, which places the first plurality of teeth 50 under the valve member 40. The valve member 40 rests on the first plurality of teeth 50, which prevents the spring 44 from returning the valve member 40 to the first locked-release position. Figure 4A and Figure 4B closed position.

[0055] Maintaining valve member 40 in the first locked release position holds pressure relief device 36 open and allows pressure to be released from interior I to areas outside interior I. Maintaining the valve in an open position after a thermal event can help prevent ventilation byproducts from continuing to accumulate within interior I, among other things.

[0056] If the flow of ventilation byproducts and the resulting pressure differential are even higher, the valve member 40 may be forced outward from the interior I past the first plurality of teeth 50 disposed on the finger 52 and past the second plurality of teeth 54. After moving past the second plurality of teeth 54, the valve member 40 may be retained by the second plurality of teeth 54. Maintaining the valve member 40 in the second locked-release position is more effective than in Fig. 6A and Figure 6B The valve member 40 in the first locked-release position allows more flow through the pressure relief device.

[0057] Although different non-limiting embodiments are shown as having specific components or steps, the embodiments of the present disclosure are not limited to these specific combinations. Some components or features from any one of the non-limiting embodiments may be used in combination with features or components from any one of the other non-limiting embodiments.

[0058] It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings.It should be understood that although particular component arrangements are disclosed and shown in these exemplary embodiments, other arrangements may also benefit from the teachings of the present disclosure.

[0059] The above description should be interpreted as illustrative and not in any limiting sense. It will be appreciated by those skilled in the art that certain modifications may occur within the scope of the present disclosure. For these reasons, the attached claims should be studied to determine the true scope and content of the present disclosure.

Claims

1. A traction battery assembly, comprising: a housing assembly having an interior region; a pressure relief device having a valve member movable from a closed position in which the valve member blocks flow through the pressure relief device from the interior region, to an unlocked-release position in which the valve member allows flow from the interior region, and from the unlocked-release position in which the valve member allows flow from the interior region; as well as A ratchet mechanism holds the valve member in the locked-release position.

2. The traction battery assembly of claim 1 wherein said valve member freely moves back and forth between said closed position and said unlocked-release position.

3. The traction battery assembly of claim 1 , wherein said valve member in said locked-release position permits more flow from said interior region than said valve member in said unlocked-release position.

4. The traction battery assembly of claim 1, further comprising: A biasing means biases the pressure relief device to the closed position and optionally wherein the biasing means is a coil spring.

5. The traction battery assembly of claim 1, wherein the ratchet mechanism includes at least one tooth.

6. The traction battery assembly of claim 1, wherein the ratchet mechanism is configured to block movement of the valve member from the locked-release position back to the unlocked-release position when the ratchet mechanism holds the valve member in the locked-release position.

7. The traction battery assembly of claim 1 , wherein the ratchet mechanism is configured to retain the valve member in a first lock-release position allowing a first amount of flow from the interior region, wherein the ratchet mechanism is further configured to retain the valve member in a second lock-release position allowing a second amount of flow from the interior region, the second flow rate being greater than the first flow rate, and optionally wherein the valve member translates along an axis when moving from the closed position to the lock-release position, the ratchet mechanism having a first plurality of teeth distributed circumferentially about the axis retaining the valve member in the first lock-release position, and the ratchet mechanism having a second plurality of teeth distributed circumferentially about the axis retaining the valve member in the second lock-release position.

8. The traction battery assembly of claim 7, further comprising: The pressure relief device has a plurality of fingers, the plurality of fingers being distributed circumferentially around the valve member, each of the fingers within the plurality of fingers comprising at least one of the teeth in the first plurality of teeth and at least one of the teeth in the second plurality of teeth.

9. The traction battery assembly of claim 1, comprising: A plurality of battery arrays are housed inside the housing assembly.

10. The traction battery assembly of claim 1 , wherein the valve member is configured to move from the closed position to the unlocked-released position in response to pressure within the interior region exceeding pressure outside the interior region by a first amount, wherein the valve member is configured to move from the unlocked-released position to the locked-released position in response to the pressure within the interior region exceeding the pressure outside the interior region by a second amount greater than the first amount.

11. A traction battery pack current control method, comprising: transitioning a valve member of the pressure relief device from a closed position to an unlocked-released position in response to a pressure within an interior region of the housing assembly exceeding a pressure outside of the interior region by a first amount; as well as In response to the pressure within the interior region of the housing assembly exceeding the pressure outside the interior region by a second amount greater than the first amount, the valve member is transitioned to a locked-release position.

12. The traction battery pack current control method of claim 11, further comprising: The valve member is held in the locked-release position using a ratchet mechanism and optionally further comprises: holding the valve member in the locked-release position using at least one tooth.

13. The traction battery flow control method of claim 12, wherein maintaining the valve member in the locked-release position blocks movement of the valve member back to the unlocked-release position or the closed position.

14. The traction battery flow control method of claim 11, wherein the pressure relief device allows more flow from the interior region when the valve member is in the locked-release position than when the valve member is in the unlocked-release position, and optionally, the traction battery flow control method further comprises: The valve member is biased toward the closed position.

15. The traction battery flow control method of claim 11, wherein the lock-release position is a first lock-release position, and the traction battery flow control method further comprises: In response to the pressure within the interior region of the housing assembly exceeding the pressure outside the interior region by a third amount that is greater than the second amount, the valve member is transitioned to a second locked-release position, and optionally, wherein the pressure relief device allows more flow from the interior region when the valve member is in the second locked-release position than when the valve member is in the first locked-release position.

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