Battery array thermal barrier with fairing

Abstract

The invention provides a battery array thermal barrier with a fairing. A battery pack assembly includes: a cell stack having a plurality of battery cells; a thermal barrier adjacent to the cell stack; and a fairing included within the thermal barrier. Each fairing is configured to move from a closed position to an open position in response to a flow of exhaust by-products against the fairing.

Description

Technical Field

[0001] The present disclosure generally relates to a thermal barrier that can direct exhaust byproducts from battery cells within a battery array of a battery pack. Background Art

[0002] The battery pack of an electrified vehicle may include groups of battery cells arranged in one or more battery arrays. Occasionally, pressure may build up within one of the battery cells and then be released through a vent in the battery cell. Summary of the invention

[0003] In some aspects, the technology described herein relates to a battery pack assembly comprising: a cell stack having a plurality of battery cells; a thermal barrier adjacent to the cell stack; and a plurality of shrouds included within the thermal barrier, each shroud being configured to move from a closed position to an open position in response to a flow of exhaust byproducts against the shroud.

[0004] In some aspects, the technology described herein relates to a battery pack assembly, each air shroud having an underside facing a plurality of battery cells, the flow of exhaust byproducts contacting the underside to move the air shroud from a closed position to an open position.

[0005] In some aspects, the technology described herein relates to a battery pack assembly wherein a shroud in a closed position covers an aperture in a thermal barrier and a shroud in an open position allows some flow through the aperture while partially covering the aperture such that flow of exhaust byproducts through the opening contacts an underside of the shroud and is redirected from flowing in a first direction to flowing in a second direction different from the first direction.

[0006] In some aspects, the technology described herein relates to a battery pack assembly wherein the opening position is a fully open position.

[0007] In some aspects, the technology described herein relates to a battery pack assembly wherein the thermal barrier includes a plurality of scored regions, each scored region establishing one of a plurality of air shrouds.

[0008] In some aspects, the technology described herein relates to a battery pack assembly in which each of a plurality of score areas is arcuate.

[0009] In some aspects, the technology described herein relates to a battery pack assembly wherein the thermal barrier includes a plurality of cutouts, each cutout establishing one of a plurality of air shrouds.

[0010] In some aspects, the technology described herein relates to a battery pack assembly in which each cutout within a plurality of cutouts has a C-shaped profile.

[0011] In some aspects, the technology described herein relates to a battery pack assembly in which each air shroud within a plurality of air shrouds is shroud-shaped.

[0012] In some aspects, the technology described herein relates to a battery pack assembly in which the thermal barrier is mica-based.

[0013] In some aspects, the technology described herein relates to a battery pack assembly in which a plurality of battery cells are arranged along an axis of the cell stack, wherein a thermal barrier is adjacent to an outer side of the cell stack, and a flow guide cover is configured to guide flow moving away from the axis of the cell stack to move along the axis of the cell stack.

[0014] In some aspects, the technology described herein relates to a battery pack assembly in which a thermal barrier is secured adjacent to a battery cell stack using a plurality of clips.

[0015] In some aspects, the technology described herein relates to a battery pack assembly in which a thermal barrier is secured adjacent to an end plate of a battery cell stack.

[0016] In some aspects, the technology described herein relates to a method of venting a battery cell, comprising: positioning a thermal barrier adjacent to a plurality of battery cells, the thermal barrier having a plurality of shrouds; moving at least one of the plurality of shrouds from a closed position to an open position in response to a flow of exhaust byproducts against the shrouds; and redirecting the flow of the exhaust byproducts using at least one of the shrouds.

[0017] In some aspects, technology described herein relates to a method that also includes scoring the thermal barrier to create a plurality of shrouds.

[0018] In some aspects, technology described herein relates to a method that also includes scoring the thermal barrier by slicing the thermal barrier.

[0019] In some aspects, the technology described herein relates to a method wherein a fairing is C-shaped.

[0020] In some aspects, the technology described herein relates to a method wherein at least one of the shrouds is in a fully open position during redirection.

[0021] In some aspects, the technology described herein relates to a method wherein a plurality of battery cells are arranged along a cell stack axis, wherein redirecting includes redirecting a flow of exhaust byproducts from moving outwardly away from the plurality of battery cells to moving along the cell stack axis.

[0022] The embodiments, examples and alternatives of the preceding paragraphs, claims or the following description and drawings, including any of their various aspects or respective individual features, may be taken 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

[0023] According to the detailed description, various features and advantages of the disclosed examples will become apparent to those skilled in the art. The drawings attached to the detailed description can be briefly described as follows:

[0024] Figure 1 A side view of an electrified vehicle with a battery pack is shown.

[0025] Figure 2 Shows Figure 1 A partial expanded view of the battery pack.

[0026] Figure 3 Shows when there is no battery cell venting Figure 2 A perspective view of the battery array of a battery pack.

[0027] Figure 4 Shows when the battery cell is vented Figure 3 A perspective view of an example battery cell of a battery pack of FIG.

[0028] Figure 5 Shows when Figure 4 When the battery cell is exhausted Figure 3 A perspective view of a battery array.

[0029] Figure 6 Shows Figure 5 Close-up view of the area.

[0030] Figure 7 Shows Figure 2 Top view of a battery pack with the housing cover removed to illustrate possible venting paths within the housing.

[0031] Figure 6 Shows Figure 3 A perspective view of a battery cell of a battery array.

[0032] Figure 7 Shows Figure 3 A close-up view of an area of ​​the battery array with the thermal barrier’s vent dampers in the open position. DETAILED DESCRIPTION

[0033] A typical traction battery pack includes a housing having an interior. An array of battery cells is held in the interior along with other components. A thermal event in one or more of the battery cells within the array can cascade to other battery cells in the battery pack (including battery cells in other battery arrays).

[0034] The present disclosure details exemplary thermal barriers that help thermally insulate a battery array. When desired, the thermal barriers can provide assistance in directing exhaust byproducts from exhausting battery cells to areas outside the battery pack and away from unexhausted battery cells.

[0035] refer to Figure 1 , the electrified vehicle 10 includes a traction battery pack 12, an electric motor 14, and wheels 16. The battery pack 12 powers the electric motor 14, which converts electrical energy into torque to drive the wheels 16. The battery pack 12 may be a relatively high voltage battery.

[0036] In the exemplary embodiment, the battery pack 12 is secured to the underbody 18 of the electrified vehicle 10. In other examples, the battery pack 12 may be located elsewhere on the electrified vehicle 10.

[0037] The electrified vehicle 10 is a pure electric vehicle. In other examples, the electrified vehicle 10 is a hybrid electric vehicle that selectively uses torque provided by an internal combustion engine (instead of or in addition to an electric machine) to drive wheels. In general, the electrified vehicle 10 can be any type of vehicle having a traction battery pack.

[0038] Reference now Figures 2 to 4 , while continuing to refer to Figure 1 , the battery pack 12 includes a housing 20 that houses a plurality of battery arrays 30 and the like. The example housing 20 includes a tray 32 and a cover 34. The example housing 20 holds eight individual battery arrays 30.

[0039] In the exemplary embodiment, each of the battery arrays 30 includes a plurality of battery cells 40, end plates 42, a top plate 44, and a pair of thermal barriers 48. The battery cells 40 of each of the battery arrays 30 are arranged along a corresponding cell stack axis A. Within each of the battery arrays 30, the battery cells 40 are compressed between the end plates 42 along the cell stack axis A.

[0040] The top plate 44 extends above the vertical upper surface of the battery cells 40. For purposes of this disclosure, vertical and horizontal are referred to with reference to the ground and the general orientation of the vehicle 10 during operation.

[0041] In an exemplary embodiment, the thermal barrier 48 is disposed beside relatively outer sides of the battery cells 40. In other examples, the thermal barrier 48 may be disposed beside other surfaces of the battery array 30, such as along an outer side of the battery array 30.

[0042] In this example, the thermal barrier 48 may include a plurality of woven fibers. The thermal barrier 48 may be mica-based. In another example, the thermal barrier 48 alternatively or additionally includes non-woven fibers. The thermal barrier 48 is a thermal insulator. The thermal barrier 48 may be considered a thermal blanket.

[0043] In one embodiment, the battery cell 40 is a lithium-ion pouch cell. However, battery cells having other geometries (cylindrical, prismatic, etc.), other chemistries (nickel-metal hydride, lead acid, etc.), or both may alternatively be used within the scope of the present disclosure.

[0044] Each of the example battery cells 40 includes a pair of tab terminals 50 extending from a housing 52. Within a given one of the battery arrays 30, the individual battery cells 40 may be electrically connected together. To provide these electrical connections, the tab terminals 50 of the battery cells 40 may be connected to tab terminals 50 of other battery cells 40, to bus bars of the battery array 30, or both.

[0045] At some point, the pressure and temperature within one of the battery cells 40 may increase and rupture the housing 52 to provide an opening 54 in the housing 52. The battery cell 40 then vents the exhaust byproducts V through the opening 54. From the opening 54, the exhaust byproducts V flow out of the cell stack axis A and against the thermal barrier 48. Although a single one of the battery cells 40 is shown as venting, more than one of the battery cells 40 may be vented simultaneously.

[0046] The accumulation of venting byproducts V between the thermal barrier 48 and other battery cells 40 that are not venting may increase thermal energy levels in those other battery cells 40 , which may cause a venting event to cascade to those other battery cells 40 .

[0047] Reference now Figures 5 to 7 And continue to refer to Figures 1 to 4 The thermal barrier 48 is therefore provided with a plurality of holes 60 which are covered by corresponding air guides 62 when no battery cells 40 are being exhausted. When the exhaust byproducts V move against the underside 64 of one of the air guides 62, the air guide 62 moves to allow flow through the holes 60. The underside 64 of each air guide 62 faces the battery cells 40.

[0048] In this example, the air deflector 62 can move from the closed position to the open position when the flow of exhaust byproducts V moves against the underside 64 of the air deflector 62. Therefore, each air deflector 62 is configured to move from the closed position to the open position in response to the flow of exhaust byproducts V against the air deflector 62.

[0049] Referring to the air deflector 62A, when the air deflector 62A is in the closed position ( Figure 3 ), the deflector 62A in the closed position covers the hole 60A in the thermal barrier 48. Figure 5 and Figure 6The deflector 62A in the fully open position (shown) exposes some of the holes 60A to allow some flow of exhaust byproducts through the holes 60A, but still partially covers the holes 60A. In this position, the deflector 62A is hood-shaped.

[0050] Since the air guide 62A partially covers the hole 60A in the fully open position, the flow of the exhaust byproducts V through the hole 60A contacts the lower side 64 of the air guide 62A. This contact redirects the exhaust byproducts V. Specifically, the exhaust byproducts V initially move through the hole 60A in the first direction D1. After contacting the lower side 64 of the air guide 62A, the exhaust byproducts V are redirected to flow in a second direction D2 that is different from the first direction D1.

[0051] In this example, the exhaust byproducts V moving in the second direction D2 move toward the outer area of ​​the battery pack 12 and away from the other battery arrays 30. After reaching the wall of the tray 32, the exhaust byproducts V have cooled slightly. The exhaust byproducts V can then flow within the battery pack 12 to one or more housing exhaust ports 68, which release the exhaust byproducts V to the ambient area around the battery pack 12. The air guide 62A can be designed to guide the exhaust byproducts V in other directions. In some examples, the exhaust byproducts V can be guided inward toward the center of the battery pack 12.

[0052] In this example, the thermal barrier 48 includes a plurality of cutouts 70 that create the air deflector 62. The cutouts 70 have an arcuate "C" shaped profile. The holes 60 may be crescent shaped. Each of the cutouts 70 creates one of the air deflectors 62. Due to the shape of the cutouts 70, the air deflectors 62 have a fish scale shape. The thermal barrier 48 may be sliced ​​to create the cutouts 70.

[0053] In another example, the cutout 70 is a scored area of ​​the thermal barrier 48. The scored area may use perforations to create the air deflector 62. The thermal barrier 48 may be sliced ​​to create the perforations. Transitioning such an air deflector 62 from a closed position to an open position may require the exhaust byproducts V to tear apart some of the thermal barrier 48.

[0054] The example thermal barrier 48 is secured along the outside of the battery array 30 using clips 72 that extend through baffles 74 in the thermal barrier 48 to engage the top plate 44 of the corresponding battery array 30. In other examples, the thermal barrier 48 may alternatively or additionally be secured using an adhesive.

[0055] Although shown along the outside, the thermal barrier 48 with the shroud 62 may alternatively or additionally be placed in other areas. For example, the thermal barrier 48 may be placed adjacent to other sides of the battery array 30, such as along the vertical top of the battery array 30 in place of the roof 44. If the battery cells 40 are susceptible to opening (i.e., venting) through the vertical top of the battery cells 40, the thermal barrier 48 with the shroud 62 may be positioned along the vertical top of the battery cells 40.

[0056] The thermal barrier 48 may also be disposed along the end plate 42 to prevent heat energy from being transferred from the battery array 30 on one side of the battery pack 12 to the battery array 30 on the other side of the battery pack 12. When disposed along the end plate 42 so that the end plate 42 is sandwiched between the battery cells 40 and the thermal barrier, the thermal barrier may not include the air deflector 62.

[0057] An example method of venting a battery pack using an example thermal barrier 48 includes positioning a thermal barrier 48 having a flow deflector 62 adjacent to a battery cell 40. Next, the method moves at least one of the flow deflectors 62 from a closed position to an open position in response to the flow of exhaust byproducts against the flow deflector 62, and then the flow deflector redirects the flow of exhaust byproducts. The redirection includes redirecting the flow of the exhaust byproduct flow V from moving outward away from the plurality of battery cells 40 to moving along the cell stack axis A.

[0058] The foregoing description is illustrative and non-restrictive in nature. Changes and modifications to the disclosed examples may become apparent to those skilled in the art, and the changes and modifications do not necessarily depart from the essence of the present disclosure. Therefore, the scope of protection granted to the present disclosure can only be determined by studying the attached claims.

Claims

1. A battery pack assembly, comprising: A battery cell stack, wherein the battery cell stack has a plurality of battery cells; A thermal barrier, the thermal barrier being adjacent to the battery cell stack; and A plurality of air shrouds are included within the thermal barrier, each air shroud being configured to move from a closed position to an open position in response to a flow of exhaust byproducts against the air shroud.

2. The battery pack assembly of claim 1, each air shroud having a lower side facing the plurality of battery cells, the flow of the exhaust byproducts contacting the lower side to move the air shroud from the closed position to the open position.

3. The battery pack assembly of claim 1 , wherein the shroud in the closed position covers the hole in the thermal barrier, and the shroud in the open position allows some flow through the hole while partially covering the hole, so that the flow of the exhaust byproducts through the opening contacts the underside of the shroud and is redirected from flowing in a first direction to flowing in a second direction different from the first direction, and optionally, wherein the open position is a fully open position.

4. The battery pack assembly of claim 1, wherein the thermal barrier comprises a plurality of scored areas, each scored area establishing one of the air ducts within the plurality of air ducts, and optionally, wherein each scored area within the plurality of scored areas is arcuate.

5. The battery pack assembly of claim 1 , wherein the thermal barrier comprises a plurality of cutouts, each cutout establishing one of the air ducts within the plurality of air ducts, and optionally, wherein each cutout within the plurality of cutouts has a C-shaped profile. 6 . The battery pack assembly as claimed in claim 1 , wherein each of the plurality of air guide covers is hood-shaped.

7. The battery pack assembly of claim 1, wherein the thermal barrier is mica based.

8. The battery pack assembly as described in claim 1, wherein the plurality of battery cells are arranged along an axis of the cell stack, wherein the thermal barrier is adjacent to an outer side of the cell stack, and the flow guide cover is configured to guide a flow moving away from the axis of the cell stack to move along the axis of the cell stack.

9. The battery pack assembly of claim 1, wherein the thermal barrier is secured adjacent to the battery cell stack using a plurality of clips.

10. The battery pack assembly of claim 1, wherein the thermal barrier is secured adjacent to an end plate of the battery cell stack.

11. A method for venting a battery cell, comprising: positioning a thermal barrier adjacent to the plurality of battery cells, the thermal barrier having a plurality of air deflectors; moving at least one of the shrouds within the plurality of shrouds from a closed position to an open position in response to a flow of exhaust byproducts against the shroud; as well as The flow of the exhaust byproducts is redirected using the at least one of the fairings.

12. The method of claim 11, further comprising scoring the thermal barrier to create the plurality of shrouds.

13. The method of claim 11, further comprising scoring the thermal barrier by slicing the thermal barrier, and optionally wherein the fairing is C-shaped.

14. The method of claim 13, wherein said at least one of said shrouds is in a fully open position during said redirecting.

15. The method of claim 13, wherein the plurality of battery cells are disposed along a cell stack axis, wherein the redirecting comprises redirecting the flow of the exhaust byproducts from moving outwardly away from the plurality of battery cells to moving along the cell stack axis.

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