BATTERY BANKS WITH SET VENTING HOLE DESIGNS

Abstract

Battery banks are provided for traction battery packs. An example battery bank may include an inner component containing a vent channel and an outer component containing a vent hole. The vent hole may be offset relative to the vent channel to create a winding vent path between the inner and outer parts of the battery bank.

Description

FIELD OF TECHNOLOGYThis disclosure relates generally to traction battery packs, and more particularly to battery banks that provide tortuous venting paths for venting battery venting byproducts from an interior of the battery bank.GENERAL STATE OF THE ARTElectrified vehicles include a traction battery pack for powering electric machines and other electrical loads of the vehicle. The traction battery pack includes a plurality of battery cells and various other in-battery components that assist electric vehicle propulsion.SUMMARYA battery bank for a traction battery pack according to an exemplary aspect of the present disclosure includes, among other things, an inner component including a vent channel and an outer component including a vent hole offset relative to the vent channel to form a convoluted vent path between an interior and an exterior of the battery bank.In a further non-limiting embodiment of the foregoing battery bank, the internal component is part of a battery cell sensing assembly.In a further non-limiting embodiment of any of the foregoing battery banks, the inner component part is a base frame of the battery cell sensing assembly.In a further non-limiting embodiment of any of the foregoing battery banks, a thermal blocker is secured to a bottom surface of the base frame.In a further non-limiting embodiment of any of the foregoing battery banks, the thermal blocker includes a second vent channel aligned with the vent channel.In a further non-limiting embodiment of any of the foregoing battery banks, the exterior component is part of a bank housing of the battery bank.In a further non-limiting embodiment of any of the foregoing battery banks, the outer component is a top cover of the bank housing.In a further non-limiting embodiment of any of the foregoing battery banks, the internal component is positioned between the top cover and a plurality of battery cells of the battery bank.In a further non-limiting embodiment of any of the foregoing battery banks, a bridging tab of the outer component extends over the top of at least a portion of the vent channel of the inner component.In a further non-limiting embodiment of any of the foregoing battery banks, the bridging tab establishes communication between the vent hole and a second vent hole of the outer component.A battery bank for a traction battery pack according to another exemplary aspect of the present disclosure includes, among other things, a bank housing, a plurality of battery cells housed within the bank housing, and a cell sensing assembly positioned between the plurality of battery cells and a cover of the bank housing. A vent hole formed by the cover is offset relative to a vent channel formed by a base frame of the cell sensing assembly.In a further non-limiting embodiment of the foregoing battery bank, the cover is a top cover of the bank housing.In a further non-limiting embodiment of any of the foregoing battery banks, a thermal blocker is secured to a bottom surface of the base frame.In a further non-limiting embodiment of any of the foregoing battery banks, the thermal blocker includes a second vent passage.In a further non-limiting embodiment of any of the foregoing battery banks, the second vent channel is aligned with the vent channel of the base frame.In a further non-limiting embodiment of any of the foregoing battery banks, the vent hole is offset relative to the vent channel to establish a tortuous vent path between an interior and an exterior of the battery bank.In a further non-limiting embodiment of any of the foregoing battery banks, a bridging tab of the cover extends over the top of at least a portion of the venting channel of the base frame.In a further non-limiting embodiment of any of the foregoing battery banks, the bridging tab establishes communication between the vent hole and a second vent hole of the cover.In a further non-limiting embodiment of any of the foregoing battery banks, the cover is a top cover of the bank housing.In a further non-limiting embodiment of any of the foregoing battery banks, the plurality of battery cells are arranged in at least two cell stack subassemblies separated by a center wall.The embodiments, examples and alternatives of the preceding paragraphs, the claims or the following description and drawings, including their various aspects or respective individual features, can be used independently of one another or in any combination. Features described in connection with an embodiment are applicable to all embodiments, unless such features are incompatible.The various features and advantages of this disclosure will become apparent to those skilled in the art from the following detailed description. The drawings attached to the detailed description may be briefly described as follows.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 schematically illustrates an electrified vehicle. FIG. 2 illustrates a battery bank of a traction battery pack. Selected portions of the battery bank are removed in FIG. 2 to illustrate internal components. FIG. 3 is a partially exploded view of the battery bank of FIG. 2. FIG. 4 is a top view of a portion of the battery bank of FIGS. 2 and 3. FIG. 5 is a cross-sectional view taken through section 5- 5 of FIG. 4.DETAILED DESCRIPTIONThis disclosure describes battery banks for traction battery packs. An example battery bank may include an inner component including a vent channel and an outer component including a vent hole. The vent hole may be offset relative to the vent channel to establish a tortuous vent path between an interior and an exterior of the battery bank. These and other features are discussed in more detail in the following paragraphs of this detailed description.FIG. 1 schematically illustrates an electrified vehicle 10. 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 could extend to other electrified vehicles, including, but not limited to, hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles, etc. Thus, although not specifically shown in the exemplary embodiment, the powertrain of the electrified vehicle 10 could be equipped with an internal combustion engine that can be used either alone or in combination with other power sources to propel the electrified vehicle 10.In the illustrated embodiment, the electrified vehicle 10 is depicted as an automobile. However, the electrified vehicle 10 could alternatively be a sport utility vehicle (SUV), van, pick-up, or any other vehicle configuration. Although a specific relationship of the components is illustrated in the figures of this disclosure, the illustrations are not intended to limit this disclosure. The placement and orientation of the various components of the electrified vehicle 10 are shown schematically and could vary within the scope of this disclosure. Furthermore, the various figures attached to this 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.In one embodiment, the electrified vehicle 10 is a fully electric vehicle propelled solely by electric power, such as by one or more electric machines 12, without any assistance from an internal combustion engine. The electric machine 12 may be operated as an electric motor, an electric generator, or both. The electric machine 12 receives electric power and may convert the electric power to torque for propelling one or more wheels 14 of the electrified vehicle 10.A voltage bus 16 may electrically couple the electric machine 12 to a traction battery pack 18. The traction battery pack 18 is an example battery of an electrified vehicle. The traction battery pack 18 may be a high voltage traction battery pack assembly that includes a plurality of battery cell arrays capable of outputting electrical power to power the electric machine 12 and / or other electrical loads of the electrified vehicle 10. Alternatively or additionally, other types of energy storage devices and / or output devices could also be used to provide electrical power to the electrified vehicle 10.The traction battery pack 18 may be secured to an underbody 20 of the electrified vehicle 10. However, the traction battery pack 18 could be located elsewhere on the electrified vehicle 10 within the scope of this disclosure.FIGS. 2, 3, 4, and 5 illustrate an example battery bank 22 for a traction battery pack, such as the traction battery pack 18 of FIG. 1. ONE OR MORE BATTERY BANKS HAVING A CONFIGURATION SIMILAR TO THE BATTERY BANK 22 SHOWN IN FIGS. 2-3 could be installed within the traction battery pack 18.The battery bank 22 may include a plurality of battery cells 24 (see cut-away portion of FIG. 2 ). In one embodiment, the battery cells 24 are lithium ion pouch cells. However, within the scope of this disclosure, battery cells having other geometries (cylindrical, prismatic, etc.) and / or chemical compositions (nickel-metal hydride, lead-acid, etc.) could alternatively be utilized. The total number of battery cells 24 provided within the battery bank 22 may vary and is not intended to limit the present disclosure.The battery cells 24 may be assembled into one or more cell stack subassemblies 26, each arranged to extend along a respective stack axis A. In the illustrated embodiment, the battery bank 22 includes two cell stack subassemblies 26 separated from each other by a center wall 28. However, within the scope of this disclosure, a greater or fewer number of cell stack subassemblies 26 could be provided within the battery bank 22. In one embodiment, the stack axes A are transverse to a longitudinal axis B of the battery bank 22.Each cell stack subassembly 26 may include a cell sensing assembly 30. The cell sensing assembly 30 may include sensing lines and other circuitry necessary to monitor voltage and temperature information associated with the battery cells 24 of each cell stack subassembly 26 of the battery bank 22.Each cell sensing assembly 30 may include a base frame 32 and a thermal blocker 34. The thermal blocker 34 may be attached to or integrally formed with a bottom surface of the base frame 32 and may be configured to protect various circuits of the cell sensing assembly 30, such as from the heat generated within the battery cells 24. Thermal blocker 34 may be made of foam, mica, fabric, or any other high temperature material within the scope of this disclosure.The cell stack subassemblies 26 and various other internal components of the battery bank 22 may be housed within a bank housing 36. The bank housing 36 may be arranged to substantially surround each cell stack subassembly 26, for example. The bank housing 36 may include a plurality of plate members that may be arranged to provide an upper cover 38, a lower cover 40, a pair of side covers 42, and a pair of end covers 44 of the battery bank 22. Two or more of the top cover 38, the bottom cover 40, the side covers 42, and the end covers 44 may be formed together as a single piece to reduce parts and complexity. For example, the bottom cover 40 and the end covers 44 may be formed together to form a U-shaped structure that covers the ends and the bottom of the battery bank 22. However, other configurations are contemplated within the scope of this disclosure.Each cell sensing assembly 30 may be positioned between the bank housing 36 and the battery cells 24. In one embodiment, each cell sensing assembly 30 is located between the top cover 38 and the top surfaces of the battery cells 24. however, other configurations are possible within the scope of this disclosure.Although rare, the battery bank 22 may be subject to a battery heat event during its operation. A battery thermal event may occur during overcharge conditions, overdischarge conditions, or other conditions, for example, and may cause one or more of the battery cells 24 to expel the battery venting byproducts, which may include gases, outflowing particles, and / or other venting byproducts.The battery bank 22 may include features configured to manage / mitigate the effects of battery heat events. For example, referring now primarily to FIGS. 3, 4, and 5, a first plurality of vent channels 46 may be formed through the base frame 32 of each cell sensing assembly 30. A second plurality of vent channels 48 may be formed through the thermal blocker 34 of each cell sensing assembly 30. The vent channels 48 may be directly aligned with the vent channels 46 to allow battery vent byproducts to flow through the cell sensing assembly 30 from the battery cell 24 undergoing the battery thermal event. In particular, such as when the thermal blocker 34 is made of a porous material (e.g., foam), preformed or pre-cut venting channels may not be a necessary feature of the thermal blocker 34.A plurality of vent holes 50 may be formed through the top cover 38 (or any other panel member) of the bank housing 36. In an assembled state of the battery bank 22, the vent holes 50 may be offset relative to the vent channels 46 to create a convoluted vent path 52 between an interior I and an exterior E of the battery bank 22 (see FIG. 5 ). For example, when battery venting byproducts are released through one or more of the battery cells 24 during a battery thermal event, the battery venting byproducts may move through one or more of the venting passages 46. However, prior to exiting through the vent holes 50, the battery vent byproducts must first change direction at least once to move axially about a bridging tab 54 that connects between adjacent vent holes 50 of the top cover 38, thereby slowing the velocity of the exiting gases.Moreover, the offset relationship between the vent channels 46 and the vent holes 50 may prevent ingress of battery vent byproducts released by adjacent battery banks and / or adjacent cell groups of the traction battery pack 18. For example, the bypass tabs 54 may at least partially prevent battery venting byproducts from adjacent battery banks from entering the battery bank 22, and the bypass tabs 54 may further at least partially prevent battery venting byproducts from adjacent cell groups from spreading to another cell group within the same battery bank 22. The proposed embodiments may therefore further serve to slow bank-to-bank and / or cell group-to-cell group spread during battery heat events.The example battery banks of this disclosure include an offset venting configuration that provides a tortuous venting path for releasing battery venting byproducts from the bank during a battery thermal event. The offset configuration serves to both reduce the velocity of venting byproducts exiting the bank and limit ingress of venting byproducts from adjacent banks into the bank.Although the various non-limiting embodiments are illustrated as having specific components or steps, the embodiments of this disclosure are not limited to these specific combinations. It is possible to use some of the components or features from any of the non-limiting embodiments in combination with features or components from any of the other non-limiting embodiments.It should be understood that like reference numerals identify corresponding or similar elements throughout the several views. It should be understood that while a particular component arrangement is disclosed and illustrated in these example embodiments, other arrangements could also benefit from the teachings of this disclosure.The foregoing description is to be interpreted as illustrative and not in a limiting sense. One of ordinary skill in the art would understand that certain modifications could be covered by the scope of the present disclosure. For these reasons, the following claims should be read in detail to determine the true scope and content of this disclosure.

Claims

A battery bank for a traction battery pack, comprising: an inner component including a vent passage; and an outer component including a vent hole offset relative to the vent passage to establish a convoluted vent path between an interior and an exterior of the battery bank.The battery bank of claim 1, wherein the internal component is part of a battery cell sensing assembly.The battery bank of claim 2, wherein the internal component is a base frame of the battery cell sensing assembly.The battery bank of claim 3, comprising a thermal blocker secured to a bottom surface of the base frame.The battery bank of claim 4, wherein the thermal blocker includes a second vent channel aligned with the vent channel.The battery bank of any preceding claim, wherein the external component is part of a bank housing of the battery bank.The battery bank of claim 6, wherein the outer component is a top cover of the bank housing.The battery bank of claim 7, wherein the internal component is positioned between the top cover and a plurality of battery cells of the battery bank.The battery bank of any preceding claim, wherein a bridging tab of the outer component extends over the top of at least a portion of the venting channel of the inner component, and optionally wherein the bridging tab connects between the venting hole and a second venting hole of the outer component.A battery bank for a traction battery pack, comprising: a bank housing; a plurality of battery cells housed within the bank housing; and a cell sensing assembly positioned between the plurality of battery cells and a cover of the bank housing, wherein a vent hole formed by the cover is offset relative to a vent channel formed by a base frame of the cell sensing assembly.The battery bank of claim 10, wherein the cover is a top cover of the bank case.The battery bank of claim 10 or 11, comprising a thermal blocker secured to a bottom surface of the base frame, and optionally wherein the thermal blocker includes a second vent channel aligned with the vent channel of the base frame.The battery bank of any of claims 10 to 12, wherein the vent hole is offset relative to the vent channel to establish a tortuous vent path between an interior and an exterior of the battery bank.The battery bank of any of claims 10 to 13, wherein a bridging tab of the cover extends over the top of at least a portion of the venting channel of the base frame, and optionally wherein the bridging tab connects between the venting hole and a second venting hole of the cover, and optionally further wherein the cover is a top cover of the bank housing.The battery bank of any of claims 10 to 14, wherein the plurality of battery cells are arranged in at least two cell stack subassemblies separated by a center wall.

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