Thermal barrier and exhaust system for traction battery array

Abstract

The invention provides a thermal barrier and exhaust system for a traction battery array. A battery array for a traction battery pack is provided. Exemplary battery arrays may include thermal barrier and exhaust systems to mitigate thermal propagation between cells and / or between groups of cells. The battery thermal barrier and exhaust system may also include one or more exhaust passages for establishing a dedicated exhaust path to exhaust gases and other effluents from the battery array during a battery thermal event.

Description

Technical Field

[0001] The present disclosure relates generally to traction battery packs and, more particularly, to thermal barriers and venting systems for managing battery cell exhaust byproducts and mitigating heat propagation during battery thermal events. Background Art

[0002] An electrified vehicle includes a traction battery pack for powering the vehicle's electric motor and other electrical loads. The traction battery pack includes a plurality of battery cells and various other battery internal components that support electric vehicle propulsion. Summary of the invention

[0003] According to an exemplary aspect of the present disclosure, a battery array for a traction battery pack includes, inter alia: a first battery cell group, the first battery cell group includes a first plurality of battery cells; a second battery cell group, the second battery cell group includes a second plurality of battery cells; and a partition assembly, the partition assembly being arranged to separate the first battery cell group from the second battery cell group. The partition assembly includes a thermal barrier plate and a seal.

[0004] In another non-limiting embodiment of the foregoing battery array, the first battery cell group and the second battery cell group are housed inside the outer array housing.

[0005] In another non-limiting embodiment of any of the foregoing battery arrays, an insulation blanket is disposed between a top plate of the outer array housing and at least one of the first battery cell group or the second battery cell group.

[0006] In another non-limiting embodiment of any of the foregoing battery arrays, the seal is configured to seal against an inner surface of the insulation blanket to isolate the first group of battery cells from the second group of battery cells.

[0007] In another non-limiting embodiment of any of the foregoing battery arrays, the insulation blanket is made of a flame retardant insulation material.

[0008] In another non-limiting embodiment of any of the foregoing battery arrays, a foam sheet is disposed between the insulation blanket and at least one of the first battery cell group or the second battery cell group.

[0009] In a further non-limiting embodiment of any of the foregoing battery arrays, the foam sheet is a polyurethane foam sheet.

[0010] In a further non-limiting embodiment of any of the foregoing battery arrays, the thermal barrier comprises mica.

[0011] In another non-limiting embodiment of any of the foregoing battery arrays, the seal is a compressible seal made of a silicone-based material.

[0012] In another non-limiting embodiment of any of the aforementioned battery arrays, the partition assembly divides the interior of the battery array into a first portion where the first battery cell group is located and a second portion where the second battery cell group is located.

[0013] In another non-limiting embodiment of any of the foregoing battery arrays, the first exhaust channel is fluidly connected to the first group of battery cells, and the second exhaust channel is fluidly connected to the second group of battery cells.

[0014] In another non-limiting embodiment of any of the foregoing battery arrays, the first exhaust channel cover is arranged to cover the first exhaust channel, and the second exhaust channel cover is arranged to cover the second exhaust channel.

[0015] In another non-limiting embodiment of any of the foregoing battery arrays, each of the first exhaust channel cover and the second exhaust channel cover includes a mica strip.

[0016] In another non-limiting embodiment of any of the foregoing battery arrays, the seal spans an upper portion of the thermal barrier.

[0017] In another non-limiting embodiment of any of the foregoing battery arrays, the seal includes an end flange section having a stepped profile.

[0018] According to another exemplary aspect of the present disclosure, a battery array for a traction battery pack includes, inter alia: an outer array shell; a first battery cell group and a second battery cell group, wherein the first battery cell group and the second battery cell group are accommodated inside the outer array shell; an insulating felt, wherein the insulating felt is arranged between a plate of the outer array shell and at least one of the first battery cell group or the second battery cell group; and a partition assembly, wherein the partition assembly includes a thermal barrier plate axially positioned between the first battery cell group and the second battery cell group and a seal arranged to seal an interface between the partition assembly and the insulating felt.

[0019] In another non-limiting embodiment of the foregoing battery array, the panel is a top panel of an outer array housing.

[0020] In a further non-limiting embodiment of any of the foregoing battery arrays, the insulation blanket supports flexible electrical wires of the battery array.

[0021] In another non-limiting embodiment of any of the foregoing battery arrays, a foam sheet is disposed between the insulation blanket and at least one of the first battery cell group or the second battery cell group.

[0022] In another non-limiting embodiment of any of the foregoing battery arrays, the first exhaust channel is fluidly connected to the first group of battery cells, and the second exhaust channel is fluidly connected to the second group of battery cells.

[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.

[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. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0026] Figure 2 The battery array of the traction battery pack is shown.

[0027] Figure 3 It passes through Figure 2 Cross-sectional view of section 3-3.

[0028] Figure 4 An exemplary seal for a thermal barrier and exhaust system is shown.

[0029] Figure 5 Shows Figure 4 The interface between the seal and the thermal barrier and the thermal barrier plate of the exhaust system.

[0030] Figure 6 Shows Figure 4 The end flange section of the seal.

[0031] Figure 7 Shows Figure 6 An interface between an end flange section and a portion of an outer array housing of the battery array. DETAILED DESCRIPTION

[0032] The present disclosure details a battery array for a traction battery pack. An exemplary battery array may include a thermal barrier and exhaust system for mitigating heat propagation between cells and / or between cell groups. The battery thermal barrier and exhaust system may also include one or more exhaust channels for establishing a dedicated exhaust path to exhaust gases and other effluents from the battery array during a battery thermal event. 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, and the like. Therefore, although not specifically shown in the exemplary embodiment, the powertrain of 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 depicted as an automobile. However, the electrified vehicle 10 may alternatively be a sport utility vehicle (SUV), 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 enlarged or minimized to emphasize certain details of a particular component or system.

[0035] In one 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 any assistance from an internal combustion engine. The electric machines 12 can operate as electric motors, generators, or both. The electric machines 12 receive electricity and can 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 assembly that includes a plurality of battery cell groups 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 power the electrified vehicle 10.

[0037] The traction battery pack 18 may be secured to an underbody 20 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.

[0038] Figure 2 and Figure 3 A traction battery pack (e.g., such as Figure 1 An exemplary battery array 22 of a traction battery pack 18). Figures 2 to 3One or more battery arrays of similar design to the battery array 22 shown in FIG. 1 may be packaged within the traction battery pack 18 .

[0039] The battery array 22 may include a plurality of battery cells 24 (see Figure 3 ). In one embodiment, the battery cells 24 are lithium-ion pouch cells. However, within the scope of the present disclosure, battery cells having other geometries (cylindrical, prismatic, etc.) and / or chemistries (nickel-metal hydride, lead acid, etc.) may alternatively be utilized. The total number of battery cells 24 disposed within the battery array 22 may vary and is not intended to limit the present disclosure.

[0040] The battery cells 24 may be stacked side by side along a stack axis to form groups of battery cells 24, sometimes referred to as "cell stacks". The cell stacks of the battery array 22 may be grouped into two or more cell groups 26. In the illustrated embodiment, each cell stack 26 includes a total of four battery cells 24. However, within the scope of the present disclosure, the cell groups 26, and therefore the battery array 22, may include any number of battery cells 24.

[0041] The outer array housing 28 of the battery array 22 can be arranged to substantially surround the battery cell group 26. In one embodiment, the outer array housing 28 completely surrounds the battery cells 24 of each battery cell group 26 and includes a top plate 30, a bottom plate 32, a pair of end plates 34, and a pair of side plates 36. One or more of the top plate 30, the bottom plate 32, the end plates 34, and the side plates 36 can be integrated together as part of an integral structure. For example, the bottom plate 32 and the end plates 34 can be integrated together to form an integral array structure that interfaces with the top plate 30. However, other configurations of the outer array housing 28 are also possible within the scope of the present disclosure.

[0042] Although rare, the battery array 22 may experience a battery thermal event during its operation. A battery thermal event may occur, for example, during an overcharge condition, an over-discharge condition, or other condition, and may cause one or more of the battery cells 24 to discharge battery exhaust byproducts, which may include gases, effluent particles, and / or other exhaust byproducts. Therefore, the battery array 22 may also include a thermal barrier and exhaust system 38 (hereinafter referred to as "system 38") for mitigating the effects of battery thermal events. For example, in addition to other benefits, the system 38 may also be configured to extend the amount of time required for electrical energy to be transferred between cells and / or between cell groups across the battery array 22 during a battery thermal event. The system 38 may also be configured to discharge the gas G and / or other effluents released by one or more of the battery cells 24 along a desired exhaust path to a location outside the battery array 22 (e.g., outside the outer array housing 28) during a battery thermal event.

[0043] Now the main reference Figure 3 , the system 38 may include one or more thermal barrier felts 40 positioned in a space extending between a top surface 42 of the battery cells 24 and an inner surface 44 of the top plate 30 of the outer array housing 28. The thermal barrier felts 40 may support one or more flexible wires 46 of the battery array 22 (e.g., of a flexible printed circuit, as schematically shown). It is noted that the various components of the system 38 are not necessarily drawn to scale, and for simplicity and clarity, the thermal barrier felts 40 are not shown in the drawings. Figure 3 2 is shown in a highly schematic manner.

[0044] Each thermal barrier felt 40 can be made of a flame retardant thermal insulation material. The flame retardant thermal insulation material can include one or more of mica, aerogel material, refractory ceramic fiber, fiberglass, etc. However, within the scope of the present disclosure, other materials or combinations of materials can be used to provide the flame retardant thermal insulation properties of the thermal barrier felt 40.

[0045] The system 38 may also include one or more foam sheets 48 positioned in the space between the top surface 42 of the battery cell 24 and the inner surface 50 of the thermal barrier felt 40. Each foam sheet 48 may be made of polyurethane foam. However, other materials or combinations of materials may be utilized to construct the foam sheets 48 within the scope of the present disclosure. The thermal barrier felt 40 and the foam sheets 48 may cooperate to protect the top plate 30 of the outer array housing 28 during a battery thermal event, such as from, for example, a relatively hot, concentrated gas jet.

[0046] The foam sheets 48 can serve multiple functions. The foam sheets 48 are generally heat resistant to both high and low temperatures. In addition, because they are insulative, they encourage heat to be vented toward desired locations and away from undesired locations. The dielectric properties of the foam material can prevent arcing between battery cells during battery thermal events. The foam sheets 48 can also prevent the introduction of contaminants, such as moisture and debris, into the battery array 22.

[0047] The system 38 may also include one or more partition assemblies 52. In one embodiment, the partition assembly 52 is axially positioned between a pair of adjacent cell groups 26 of a cell stack of the battery array 22. The partition assembly 52 may additionally interface with the thermal barrier felt 40. As discussed further below, the partition assembly 52 may isolate a first portion P1 of the interior of the battery array 22 (where a first cell group 26 of the cell groups 26 is located) from a second portion P2 of the interior (where an adjacent cell group 26 is located).

[0048] The partition assembly 52 may include a thermal barrier 54 and a seal 56. The thermal barrier 54 may be positioned axially between a pair of adjacent cell groups 26 of the battery array 22. The thermal barrier 54 may be a single-layer or multi-layer structure designed to mitigate heat propagation between cell groups during a battery thermal event. In one embodiment, the thermal barrier 54 is made of mica. However, within the scope of the present disclosure, other flame retardant insulation materials or combinations of materials may also be utilized as part of the thermal barrier 54.

[0049] The seal 56 of the partition assembly 52 can be configured to seal the interface between the thermal barrier plate 54 and the thermal barrier felt 40. Therefore, the thermal barrier plate 54 and the seal 56 can cooperate to divide the interior of the battery array 22 into a first portion P1 and a second portion P2. The seal 56 can be arranged to extend between the inner surface 50 of the thermal barrier felt 40 and the upper portion 58 of the thermal barrier plate 54. The upper portion 58 can extend above the top surface 42 of the battery cell 24.

[0050] In one embodiment, for example, the seal 56 is made of a compressible material, such as a silicone-based material. However, other compressible materials or combinations of materials are also contemplated within the scope of the present disclosure.

[0051] The system 38 may also include a plurality of exhaust channels 60 for exhausting gas G or other effluents from the battery array 22 along an established and predictable gas path during a battery thermal event. The exhaust channels 60 may be established by slots or openings formed through each of the top plate 30, the thermal barrier felt 40, and the foam sheet 48.

[0052] Each cell group 26 of the battery array 22 may include one or more dedicated exhaust channels 60. For example, a first portion of the exhaust channel 60 may be in fluid communication with a first portion P1 of the interior of the battery array 22, and a second portion of the exhaust channel 60 may be in fluid communication with a second portion P2 of the interior of the battery array 22. Thus, no matter which cell group 26 is experiencing a battery thermal runaway event and without substantially transferring heat to an adjacent cell group 26, the gas G may be exhausted from the battery array 22.

[0053] Each exhaust channel 60 may be covered by an exhaust channel cover 62. For example, one end of each exhaust channel cover 62 may be fixed to the top plate 30, such as by a section of double-sided tape. The exhaust channel cover 62 may be configured to open during a battery exhaust event to allow gas G to pass through the exhaust channel 60. The exhaust channel cover 62 may be made of mica strips, ceramic paper, glass mat thermoplastic composites, and the like.

[0054] Figure 4 and Figure 5An exemplary design of a seal 56 of the divider assembly 52 of the above-described system 38 is shown. The seal 56 may include a base portion 64 and a bulb portion 66 extending from the base portion 64. The base portion 64 may be configured to interface with the thermal barrier plate 54 of the divider assembly 52, and the bulb portion 66 may be configured to interface with the inner surface 50 of the thermal barrier felt 40.

[0055] The base portion 64 of the seal 56 may be arranged to straddle the upper portion 58 of the thermal barrier 54 (see, e.g., Figure 5 For example, when the seal 56 is received over the thermal baffle 54 , the protruding legs 68 of the base portion 64 may be located to the side of the upper portion 58 of the thermal baffle 54 .

[0056] The bulbous portion 66 of the seal 56 may be hollow and may include a semi-cylindrical shape. However, other configurations are contemplated within the scope of the present disclosure.

[0057] Reference now Figure 6 and Figure 7 , the seal 56 may include one or more end flange sections 70. Each end flange section 70 may be designed to interface with a portion of the outer array housing 28. For example, the end flange section 70 may include a stepped profile 72 for interfacing with one of the end plates 34 of the outer array housing 28 (see Figure 7 ). Thus, the seal 56 may be sufficiently supported along its length to establish a sealing interface relative to the thermal barrier felt 40.

[0058] The exemplary battery array of the present disclosure includes a battery thermal barrier and venting system for mitigating or even preventing heat propagation within an electrified vehicle traction battery array. The proposed system can provide numerous advantages over known solutions, including but not limited to providing a novel configuration that significantly slows or even prevents heat propagation between cells and between cell groups while providing a dedicated venting channel for exhausting battery exhaust byproducts during battery thermal events.

[0059] 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 of the non-limiting embodiments may be used in combination with features or components from any of the other non-limiting embodiments.

[0060] 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.

[0061] The foregoing description should be interpreted as illustrative and not in any limiting sense. Those of ordinary skill in the art will appreciate 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 battery array for a traction battery pack, the battery array comprising: a first battery cell group, the first battery cell group comprising a first plurality of battery cells; a second battery cell group, the second battery cell group comprising a second plurality of battery cells; as well as a partition assembly arranged to separate the first battery cell group from the second battery cell group, The partition assembly includes a thermal barrier plate and a sealing member.

2. The battery array of claim 1, wherein the first battery cell group and the second battery cell group are housed inside an outer array casing.

3. A battery array as described in claim 2, comprising an insulation felt arranged between a top plate of the outer array shell and at least one of the first battery cell group or the second battery cell group, and optionally, wherein the seal is configured to seal against an inner surface of the insulation felt to isolate the first battery cell group from the second battery cell group. The battery array according to claim 3 , wherein the thermal insulation felt is made of a flame retardant thermal insulation material.

5. The battery array of claim 3, comprising a foam sheet disposed between the insulation blanket and at least one of the first battery cell group or the second battery cell group, and optionally wherein the foam sheet is a polyurethane foam sheet.

6. A battery array as claimed in any preceding claim, wherein the thermal barrier comprises mica and the seal is a compressible seal comprised of a silicone based material. 7 . The battery array according to claim 1 , wherein the partition assembly divides the interior of the battery array into a first portion where the first battery cell group is located and a second portion where the second battery cell group is located.

8. The battery array of any preceding claim, comprising a first exhaust channel fluidly connected to the first cell group and a second exhaust channel fluidly connected to the second cell group, and further comprising: a first exhaust passage cover, the first exhaust passage cover being arranged to cover the first exhaust passage; and a second exhaust channel cover arranged to cover the second exhaust channel, and optionally wherein each of the first exhaust channel cover and the second exhaust channel cover comprises a mica strip.

9. A battery array as claimed in any preceding claim, wherein the seal spans an upper portion of the thermal barrier.

10. A battery array as claimed in any preceding claim, wherein the seal comprises an end flange section having a stepped profile.

11. A battery array for a traction battery pack, the battery array comprising: an outer array housing; a first battery cell group and a second battery cell group, wherein the first battery cell group and the second battery cell group are accommodated inside the outer array housing; A thermal insulation felt, the thermal insulation felt being arranged between a top plate of the outer array housing and at least one of the first battery cell group or the second battery cell group; as well as A partition assembly includes a thermal barrier plate axially positioned between the first cell group and the second cell group and a seal arranged to seal an interface between the partition assembly and the insulation blanket.

12. The battery array of claim 11, wherein the plate is a top plate of the outer array housing.

13. The battery array of claim 11 or 12, wherein the insulation blanket supports flexible electrical wires of the battery array. 14 . The battery array according to claim 11 , comprising a foam sheet disposed between the insulation felt and at least one of the first battery cell group or the second battery cell group.

15. The battery array of any one of claims 11 to 14, comprising a first exhaust channel fluidly connected to the first battery cell group and a second exhaust channel fluidly connected to the second battery cell group.

Images