Thermal barrier assembly for traction battery pack

Abstract

The present disclosure provides a thermal barrier assembly for a traction battery pack. A traction battery pack assembly includes a housing assembly providing an interior region. A stack of cells is disposed within the interior region. The cell stack has a plurality of battery cells disposed along an axis of the cell stack. The terminal tabs of the battery cells protrude outwardly from the cell stack axis. A thermal barrier is located within the interior region. The thermal barrier has fingers that are spaced apart from each other to provide at least one slot that receives a portion of at least one of the terminal tabs.

Description

Technical Field

[0001] The present disclosure relates generally to a thermal barrier for a traction battery pack, and more particularly to a thermal barrier having a plurality of fingers. Background Art

[0002] The traction battery pack of an electrified vehicle may include a housing assembly that holds a group of battery cells arranged into one or more cell stacks. The open areas within the housing may be filled with various types of thermal barriers to help control heat spread. Summary of the invention

[0003] In some aspects, the technology described herein relates to a traction battery pack assembly, comprising: a housing assembly providing an interior region; a cell stack within the interior region, the cell stack having a plurality of battery cells arranged along an axis of the cell stack and a plurality of terminal tabs protruding outward from the axis of the cell stack; and a thermal barrier within the interior region, the thermal barrier having a plurality of fingers spaced apart from each other to provide at least one slot that receives a portion of at least one of the plurality of terminal tabs.

[0004] In some aspects, the technology described herein relates to a traction battery pack assembly wherein the plurality of fingers includes at least one first finger on a first side of the cell stack and at least one second finger on an opposing second side of the cell stack.

[0005] In some aspects, the technology described herein relates to a traction battery pack assembly wherein the at least one first finger and the at least one second finger each extend longitudinally from a heat barrier base disposed alongside a third side of the battery cell stack.

[0006] In some aspects, the technology described herein relates to a traction battery pack assembly wherein a cross-section of the thermal barrier taken through the at least one first finger, the thermal barrier base, and the at least one second finger has a “C” shape.

[0007] In some aspects, the technology described herein relates to a traction battery pack assembly wherein the third side is transverse to both the first side and the second side.

[0008] In some aspects, the technology described herein relates to a traction battery pack assembly wherein the at least one first finger extends longitudinally from the heat barrier base to a tapered end portion, wherein the at least one second finger extends longitudinally from the heat barrier base to a tapered end portion.

[0009] In some aspects, the technology described herein relates to a traction battery pack assembly wherein the at least one first finger and the at least one second finger are a first material, wherein the thermal barrier base is a second material different than the first material.

[0010] In some aspects, the technology described herein relates to a traction battery pack assembly wherein the first material is a closed cell foam and the second material is a polymer-based material.

[0011] In some aspects, the technology described herein relates to a traction battery pack assembly, wherein the plurality of fingers are a plurality of first fingers, the plurality of first fingers are part of a first thermal barrier comb disposed along a first side of a battery cell stack, and the traction battery pack assembly further comprises a second thermal barrier comb disposed along an opposite second side of the battery cell stack, the second thermal barrier comb having a plurality of second fingers, the plurality of second fingers being spaced apart from one another to provide at least one narrow slot, the at least one narrow slot receiving a portion of at least one of the plurality of terminal tabs.

[0012] In some aspects, the technology described herein relates to a traction battery pack assembly wherein the thermal barrier is a closed cell foam.

[0013] In some aspects, the technology described herein relates to a traction battery pack assembly, wherein the battery cell stack is a first battery cell stack, and the traction battery pack assembly further includes at least one second battery cell stack within the interior region.

[0014] In some aspects, the technology described herein relates to a traction battery pack assembly, wherein the plurality of battery cells are a plurality of pouch-type battery cells, each pouch-type battery cell having a crimping edge that protrudes outward from the cell stack axis around a circumferential periphery of the pouch-type battery cell, wherein the at least one narrow slot receives a portion of at least one of the crimping edges.

[0015] In some aspects, the technology described herein relates to a traction battery pack assembly wherein each of the terminal tabs within the plurality of terminal tabs extends through one of the crimping edges.

[0016] In some aspects, the technology described herein relates to a traction battery pack assembly, comprising: a thermal barrier having a plurality of fingers spaced apart from one another to provide a plurality of slots, each of the slots within the plurality of slots being configured to receive a portion of at least one terminal tab extending from a battery cell.

[0017] In some aspects, the technology described herein relates to a traction battery pack assembly wherein the thermal barrier is a closed cell foam.

[0018] In some aspects, the technology described herein relates to a method of providing a thermal barrier within a battery pack, the method comprising: placing a battery cell stack within an interior area of ​​a housing; inserting the thermal barrier into the interior area; and during the insertion, receiving at least one terminal tab of the battery cell stack within a slot of the thermal barrier.

[0019] In some aspects, the technology described herein relates to a method wherein the slot is disposed between first and second fingers of the thermal barrier.

[0020] In some aspects, the technology described herein is directed to a method wherein the first fingers and the second fingers are closed cell foams.

[0021] In some aspects, technology described herein relates to a method in which a first finger and a second finger each have a tapered end portion.

[0022] In some aspects, the technology described herein is directed to a method in which a first finger and a second finger each extend longitudinally from a thermal barrier base.

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

[0024] 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:

[0025] Figure 1 A side view of an example electrified vehicle is shown.

[0026] Figure 2 The present invention shows an exemplary aspect of the present invention. Figure 1 An expanded perspective view of a battery pack for an electric vehicle.

[0027] Figure 3 Shows Figure 2 The battery cells of the battery pack.

[0028] Figure 4 Shows when thermal barriers are installed Figure 2 Cross-sectional view of a battery pack.

[0029] Figure 5 Shows when thermal barriers are installed Figure 2 A perspective view of a corner portion of a battery pack.

[0030] Figure 6 Shows Figure 4 Close-up view of the area.

[0031] 7A to 7C Shown from Figure 2 Various views of one of the thermal barriers of a battery pack.

[0032] Fig. 8A and Figure 8B Shown are selected views of a thermal barrier according to another exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0033] The present disclosure details exemplary thermal barriers for use in traction battery packs. The thermal barriers can, among other things, help shield unventilated battery cells from thermal energy associated with ventilated battery cells. Shielding unventilated battery cells from thermal energy can help prevent thermal energy levels in these battery cells from increasing and causing these battery cells to ventilate.

[0034] refer to Figure 1 , the electrified vehicle 10 includes a battery pack 14, an electric motor 18, and wheels 22. The battery pack 14 supplies power to the electric motor 18, which can convert electricity into mechanical power to drive the wheels 22.

[0035] In the exemplary embodiment, the battery pack 14 is secured to an underbody 26 of the electrified vehicle 10. In other examples, the battery pack 14 may be located elsewhere on the electrified vehicle 10.

[0036] 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 (as an alternative or supplement to an electric machine) to drive wheels. In general, the electrified vehicle 10 can be any type of vehicle having a traction battery pack.

[0037] Reference now Figure 2 and Figure 3 , the battery pack 14 includes a plurality of cell stacks 30 held within a housing assembly 34. In the exemplary embodiment, the housing assembly 34 includes a housing cover 38 and a housing tray 42. The housing cover 38 is secured to the housing tray 42 to provide an interior area 44 that accommodates the cell stacks 30. The housing cover 38 may be secured to the housing tray 42 using, for example, mechanical fasteners (not shown).

[0038] Each of the cell stacks 30 includes a plurality of battery cells 50 (or simply “cells”) disposed along a corresponding cell stack axis A. Within each cell stack 30 , the battery cells 50 are stacked side by side along the cell stack axis A relative to one another. Figure 2 The battery cell 50 is shown in highly schematic form.

[0039] The battery cells 50 can store and supply electricity. Although a specific number of battery cell stacks 30 and battery cells 50 are shown in various figures of this disclosure, the battery pack 14 can include any number of battery cell stacks 30 having any number of individual battery cells 50 .

[0040] In the exemplary embodiment, the battery cell 50 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 utilized within the scope of the present disclosure.

[0041] The example battery cell 50 includes a crimping edge 54 where a first housing 58A of the battery cell 50 is joined to a second housing 58B of the battery cell 50. The crimping edge 54 may extend partially or completely around the circumferential periphery of the associated battery cell 50. Terminal tabs 62 of the battery cell 50 protrude outwardly away from the cell stack axis A through the crimping edge 54. When the battery cell 50 is within the cell stack 30, the terminal tabs 62 extend outwardly from the cell stack axis A and may be connected to, for example, a bus bar.

[0042] At times, pressure and heat may increase within one or more of the battery cells 50. For example, the increase in pressure and heat may be caused by an overcharge condition. The increase in pressure and heat may rupture the associated battery cell 50 and expel vent byproducts, such as gas and debris, from within the battery cell 50.

[0043] The vent byproducts may be released from the associated battery cell 50 through a ruptured area of ​​the associated battery cell 50. The vent byproducts may be released through a ruptured area of ​​the crimped edge 54. The vent byproducts may also be released through a designated vent in one or both of the first shell 58A and the second shell 58B. The designated vent may be a diaphragm that yields in response to increased pressure.

[0044] In these examples, the battery pack 14 includes a cross member assembly 66 disposed between the battery stacks 30. The example cross member assembly 66 extends longitudinally in a direction parallel to the battery stack axis A. The cross member assembly 66 and the battery stack axis A extend in the vehicle transverse direction (i.e., from the driver side to the passenger side). Bus bars connected to the terminal tabs 62 can be mounted to the cross member assembly 66.

[0045] In this example, the cross member assembly 66 may include a ventilation passage. Vent byproducts from one or more of the battery cells 50 may move through at least one of the openings 70 into the ventilation passage. The vent byproducts are transmitted through the ventilation passage through the housing vents 74 to an area outside the battery pack 14. For example, when not ventilated, the openings 70, the housing vents 74, or both may be covered by a corresponding diaphragm. During ventilation, the vent byproducts may rupture the diaphragm so that the vent byproducts may flow from the battery cells 50 through the openings 70 to the ventilation passage and then through the housing vents 74.

[0046] In another example, vent byproducts from one or more of the battery cells 50 are directed through one or more vents in the housing cover 38 of the traction battery pack 14. Other methods of conveying vent byproducts from the traction battery pack 14 are possible and within the scope of the present disclosure.

[0047] The battery pack 14 includes a plurality of thermal barriers 78 within the interior region 44. The thermal barriers 78 include portions disposed along at least the exterior sides 82 of the battery stack 30. When one or more of the battery cells 50 within a given battery stack 30 are ventilated through one of the exterior sides 82, the thermal barriers 78 along that exterior side 82 may help prevent heat energy from swirling against other battery cells 50 that are not ventilated.

[0048] Reference now Figures 4 to 7C And continue to refer to Figure 2 and Figure 3 In the exemplary embodiment, the thermal barrier 78 has a plurality of fingers 86 that are spaced apart from one another to provide a plurality of slots 90. When the thermal barrier 78 is installed within the battery pack 14, the slots 90 each receive a portion of one or more of the terminal tabs 62 extending from one or more of the battery cells 50. The slots 90 additionally receive a portion of the crimping edge 54 from one or more of the battery cells 50.

[0049] In this example, the thermal barrier 78 includes: a plurality of first fingers 86A, which can be placed along one of the outer sides 82 of one of the battery stacks 30; and a plurality of second fingers 86B, which can be placed along the opposite outer side of the battery stack 30. The plurality of first fingers 86A and the plurality of second fingers 86B each extend longitudinally from a thermal barrier base 94, which is disposed along the other side of the battery stack 30 (here, the upper side of the battery stack 30). In this example, the outer sides 82 are substantially parallel to each other. The third side is transverse to (here, perpendicular to) the outer sides 82. A cross-section of the thermal barrier taken through one of the first fingers, the base, and one of the second fingers has a "C" shape, such as Figure 7C shown.

[0050] The first finger 86A and the second finger 86B each include a tapered end portion 96. The first finger 86A and the second finger 86B each extend longitudinally from the thermal barrier base 94 to the tapered end portion 96. During installation, the tapered end portion 96 may help guide the first finger 86A and the second finger 86B into an installed position.

[0051] The housing tray 42 may include recessed features 98 that each receive a portion of one of the tapered end portions 96. Receiving the tapered end portions 96 within the recessed features 98 may help align and position the fingers 86 during assembly.

[0052] In this example, the first finger 86A, the second finger 86B and the thermal barrier base 94 are molded closed-cell foam structures. In another example, the first finger 86A and the second finger 86B can be a first material, such as closed-cell foam, and the thermal barrier base 94 is a different second material, such as a polymer-based material.

[0053] In some examples, the thermal barrier 78 may include internal reinforcements that may help strengthen and stabilize, particularly during installation. The internal reinforcements may be a polymer-based material or a relatively rigid foam.

[0054] refer to Fig. 8A and Figure 8B In another embodiment, the first finger 86A and the second finger 86B are each part of a separate comb-shaped thermal barrier structure. The first finger 86A can be, for example, part of a first thermal barrier comb 102 that can be disposed along one of the outer sides 82 of the battery cell stack 30. The first thermal barrier comb 102 does not include a thermal barrier base that spans the vertical upper side of the associated battery array. The second finger 86B can be part of a second thermal barrier comb (not shown) that can be disposed along the opposite outer side 82 of the battery cell stack 30.

[0055] for Figure 2 An exemplary method of providing a thermal barrier to the battery pack 14 may include placing the cell stack 30 within the interior region 44. Next, the thermal barrier 78 is inserted into the interior region 44. The thermal barrier 78 is inserted so that at least one of the terminal tabs 62 is received within one of the slots 90 of the thermal barrier 78. The thermal barrier 78 may be mounted to the cell stack 30 from above or below. In some examples, such as when the thermal barrier base 94 spans below the vertical bottom of the cell stack 30, the heat exchange plate may be clamped against the cell stack 30.

[0056] Features of the disclosed examples include providing a thermal barrier that facilitates installation, among other things, by reducing part complexity. Multiple fingers of the thermal barrier may be installed simultaneously, rather than individually. This may reduce build complexity and tool complexity. The thermal barrier may be a closed cell foam that may have closed cell edges that promote reduced moisture absorption. In some examples, liquid foam is not required. The tapered ends of the exemplary foam fingers assist in positioning the foam fingers during installation.

[0057] 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.

[0058] According to the present invention, a traction battery pack assembly is provided, the traction battery pack assembly having: a thermal barrier having a plurality of fingers, the plurality of fingers being spaced apart from each other to provide a plurality of slots, each of the slots within the plurality of slots being configured to receive a portion of at least one terminal tab extending from a battery cell.

[0059] According to one embodiment, the thermal barrier is a closed cell foam.

Claims

1. A traction battery pack assembly, comprising: a housing assembly providing an interior region; a cell stack within the interior region, the cell stack having a plurality of battery cells arranged along a cell stack axis, each battery cell within the plurality of battery cells including at least one terminal tab projecting outwardly from the cell stack axis; as well as A thermal barrier within the interior region, the thermal barrier having a plurality of fingers spaced apart from one another to provide at least one slot that receives a portion of the at least one terminal tab.

2. The traction battery pack assembly of claim 1 , wherein the plurality of fingers include at least one first finger on a first side of the cell stack and at least one second finger on an opposite second side of the cell stack, and optionally, wherein the at least one first finger and the at least one second finger each extend longitudinally from a thermal barrier base disposed adjacent a third side of the cell stack.

3. The traction battery pack assembly of claim 2, wherein a cross-section of the thermal barrier taken through the at least one first finger, the thermal barrier base, and the at least one second finger has a "C" shape. 4 . The traction battery pack assembly of claim 2 , wherein the third side is transverse to both the first side and the second side.

5. The traction battery pack assembly of claim 2, wherein the at least one first finger extends longitudinally from the heat barrier base to the tapered end portion, wherein the at least one second finger extends longitudinally from the heat barrier base to the tapered end portion.

6. The traction battery pack assembly of claim 2, wherein the at least one first finger and the at least one second finger are a first material, wherein the thermal barrier base is a second material different from the first material, and optionally, wherein the first material is a closed cell foam and the second material is a polymer-based material.

7. The traction battery pack assembly of claim 1 , wherein the plurality of fingers are a plurality of first fingers, the plurality of first fingers being part of a first thermal barrier comb disposed along a first side of a battery cell stack, and the traction battery pack assembly further comprising a second thermal barrier comb disposed along an opposite second side of the battery cell stack, the second thermal barrier comb having a plurality of second fingers, the plurality of second fingers being spaced apart from one another to provide at least one slot, the at least one slot receiving a portion of at least one of the plurality of terminal tabs.

8. The traction battery pack assembly of claim 1 wherein the thermal barrier is a closed cell foam. 9 . The traction battery pack assembly of claim 1 , wherein the battery cell stack is a first battery cell stack, and the traction battery pack assembly further comprises at least one second battery cell stack within the interior region.

10. The traction battery pack assembly of claim 1, wherein the plurality of battery cells are a plurality of pouch-type battery cells, each pouch-type battery cell having a crimping edge that protrudes outwardly from the cell stack axis around a circumferential periphery of the pouch-type battery cell, wherein the at least one narrow slot receives a portion of at least one of the crimping edges, and optionally, wherein each of the terminal tabs within the plurality of terminal tabs extends through one of the crimping edges.

11. A method of providing a thermal barrier in a battery pack, comprising: placing the battery cell stack within the interior area of ​​the housing; inserting a thermal barrier into the interior region; as well as During the inserting, at least one tab terminal of the cell stack is received within a slot of the thermal barrier.

12. The method of claim 11, wherein the slot is disposed between a first finger and a second finger of the thermal barrier.

13. The method of claim 12, wherein the first fingers and the second fingers are closed cell foams.

14. The method of claim 12, wherein the first finger and the second finger each have a tapered end portion.

15. The method of claim 12, wherein the first finger and the second finger each extend longitudinally from a thermal barrier base.

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