HEAT MANAGEMENT ASSEMBLY FOR A TRACTION BATTERY PACK

Abstract

A traction battery pack assembly comprises a housing assembly, which provides an interior space, and a cell stack within the interior space. The cell stack contains battery cells arranged along a cell stack axis. A thermal management assembly is arranged along the cell stack axis. The thermal management assembly includes thermal blockers secured to a base assembly. The base assembly includes an inserted region and at least one protruding region. The inserted region is arranged along the cell stack axis and is inserted between a first and second battery cell. The protruding region is located outside the inserted region with respect to the cell stack axis. The thermal blockers are secured to the at least one protruding region of the base assembly.

Description

FIELD OF TECHNOLOGY

[0001] This disclosure generally relates to managing thermal energy within a traction battery pack. GENERAL STATE OF THE ART

[0002] A traction battery pack of an electrified vehicle may contain groups of battery cells arranged in one or more cell stacks. From time to time, pressure and thermal energy may increase within one or more of the battery cells, causing gas and deposits to vent from those battery cells. SUMMARY

[0003] In some aspects, the techniques described in this document relate to a traction battery pack assembly including: a housing assembly providing an interior space; a cell stack within the interior space, the cell stack comprising a plurality of battery cells arranged along a cell stack axis;and a thermal management assembly disposed along the cell stack axis, the thermal management assembly including a plurality of heat blockers secured to a base assembly, the base assembly including an inserted region and at least one protruding region, the inserted region disposed along the cell stack axis and inserted between a first and second battery cell, the at least one protruding region being located outside the inserted region with respect to the cell stack axis, the plurality of heat blockers being secured to the at least one protruding region of the base assembly;

[0004] In some aspects, the techniques described in this document relate to a traction battery pack assembly, wherein the plurality of battery cells includes a plurality of pouch-style battery cells.

[0005] In some aspects, the techniques described herein relate to a traction battery pack assembly, wherein the plurality of heat blockers include heat blockers secured to opposite axial sides of the at least one protruding region on a first exterior side of the cell stack.

[0006] In some aspects, the techniques described herein relate to a traction battery pack assembly, wherein the plurality of heat blockers further includes heat blockers secured to opposite axial sides of the at least one protruding region on an opposite, second exterior side of the cell stack.

[0007] In some aspects, the techniques described herein relate to a traction battery pack assembly further including an adhesive that secures the plurality of heat blockers to the at least one protruding region of the base assembly.

[0008] In some aspects, the techniques described in this document relate to a traction battery pack assembly wherein the adhesive is an adhesive tape.

[0009] In some aspects, the techniques described in this document relate to a traction battery pack assembly, wherein the base assembly includes a thermal barrier, wherein the adhesive tape includes a first piece of adhesive tape on a first axial side of the thermal barrier and a second piece of adhesive tape on an opposite, second axial side of the thermal barrier.

[0010] In some aspects, the techniques described herein relate to a traction battery pack assembly, wherein the first piece of adhesive tape secures at least one heat blocker of the plurality of heat blockers on a first exterior side of the cell stack to the at least one protruding region and secures at least one other heat blocker of the plurality of heat blockers on an opposite, second exterior side of the cell stack to the at least one protruding region.

[0011] In some aspects, the techniques described in this document relate to a traction battery pack assembly wherein the base assembly is provided entirely by an adhesive tape.

[0012] In some aspects, the techniques described in this document relate to a traction battery pack assembly, wherein the thermal management assembly is configured to prevent vent byproducts expelled from one or more battery cells on a first axial side of the thermal management assembly from moving adjacent to battery cells on an opposite, second axial side of the thermal management assembly.

[0013] In some aspects, the techniques described in this document relate to a battery pack assembly, wherein the base assembly is made of a first material and the heat blocker is made of a second, different material.

[0014] In some aspects, the techniques described in this document relate to a traction battery pack assembly wherein the heat blocker is made of foam.

[0015] In some aspects, the techniques described in this document relate to a traction battery pack assembly wherein the base assembly includes mica.

[0016] In some aspects, the techniques described in this document relate to a method for managing thermal energy of a battery pack, including: supporting heat blockers disposed on opposite sides of a cell stack within a housing assembly using a base assembly of a thermal management assembly, the base assembly being at least partially interposed between a first and a second battery cell of the cell stack.

[0017] In some aspects, the techniques described in this document relate to a method that further includes adhesively securing the heat blockers to the base assembly.

[0018] In some aspects, the techniques described herein relate to a method that further includes adhesively securing at least some of the heat blockers to a first axial side of the base assembly using adhesive tape.

[0019] In some aspects, the techniques described in this document relate to a method that further includes securing the first battery cell to the first axial side of the base assembly using the adhesive tape.

[0020] In some aspects, the techniques described in this document relate to a method that further includes securing some of the heat blockers and the second battery cell to an opposite, second side of the base assembly using adhesive tape.

[0021] In some aspects, the techniques described herein relate to a method wherein the base assembly and an adhesive tape are used.

[0022] The embodiments, examples, and alternatives of the preceding paragraphs, the claims, or the following description and drawings, including any of their various aspects or respective individual features, may be considered independently of one another or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are inconsistent. SHORT DESCRIPTION OF THE CHARACTERS

[0023] The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description. The figures accompanying the detailed description may be briefly described as follows: Fig. 1 illustrates a side view of an exemplary electrified vehicle. Fig. 2 illustrates an exploded perspective view of a battery pack from the electrified vehicle Fig. 1. Fig. Figure 3 illustrates an exploded section of a cell stack from Fig. 2. Fig. 4-6 illustrate views of an exemplary thermal management assembly from the battery pack Fig. 2. Fig. 7-9 illustrate views of another exemplary thermal management assembly from the battery pack Fig. 2. DETAILED DESCRIPTION

[0024] This disclosure describes exemplary thermal management assemblies for a traction battery pack in detail. The thermal management assemblies may, among other things, help secure battery cells together and help direct venting byproducts during a thermal event. The thermal management assemblies may include a plurality of thermal blockers. Thus, separate installation of thermal blockers may not be required.

[0025] With reference to Fig. 1, an electrified vehicle 10 includes a battery pack 14, an electric machine 18, and wheels 22. The battery pack 14 supplies power to an electric machine 18 that can convert electrical power into mechanical power to drive the wheels 22.

[0026] In the exemplary embodiment, the battery pack 14 is attached to an underbody 26 of the electrified vehicle 10. In other examples, the battery pack 14 could be located elsewhere on the electrified vehicle 10.

[0027] The electrified vehicle 10 is a fully electric vehicle. In other examples, the electrified vehicle 10 is a hybrid electric vehicle that selectively drives wheels using torque provided by an internal combustion engine instead of or in addition to an electric machine. In general, the electrified vehicle 10 could be any type of vehicle that includes a battery pack.

[0028] With reference to Fig. 2 and Fig. 3, the battery pack 14 includes a plurality of cell stacks 30 held within an interior space of a housing assembly 34. In the exemplary embodiment, the housing assembly 34 includes a housing cover 38 and a housing shell 42. The housing cover 38 is secured to the housing shell 42 to provide an interior area 44 in which the cell stacks 30 are housed. The housing cover 38 may be secured to the housing shell 42, for example, using mechanical fasteners (not shown).

[0029] Each of the cell stacks 30 includes a plurality of battery cells 50 (or simply "cells") and a plurality of thermal management assemblies 54. Within each of the cell stacks 30, the cells 50 are provided in groups and arranged along a cell stack axis A. The thermal management assemblies 54 are arranged between groups of the cells 50 along the cell stack axis A.

[0030] The battery cells 50 store and deliver electrical power. Although specific numbers of cell stacks 30 and cells 50 are illustrated in the various figures of this disclosure, the battery pack 14 could include any number of cell stacks 30 having any number of individual cells 50. The groups of battery cells 50 can include multiple battery cells 50 or just one battery cell 50. In one embodiment, the battery cells 50 are pouch-style lithium-ion battery cells. Alternatively, however, battery cells having other geometries (cylindrical, prismatic, etc.), other chemistries (nickel-metal hydride, lead-acid, etc.), or both could be utilized within the scope of this disclosure.

[0031] From time to time, pressure and thermal energy may increase within one or more of the battery cells 50. The increase in pressure and thermal energy may be due, for example, to an overcharge condition. The increase in pressure and thermal energy may cause the associated battery cell 50 to rupture and expel venting byproducts, such as gas and debris, from within the battery cell 50. The venting byproducts may be released from the associated battery cell 50 through a defined vent opening 60 in the enclosure, such as a membrane that yields in response to increased pressure, or through a ruptured portion of the associated battery cell 50.

[0032] The venting byproducts may have relatively high thermal energy levels. By directing the venting byproducts away from other battery cells 50 that are not being vented, these battery cells 50 may be prevented from being vented and the venting event may be prevented from cascading through the battery pack 14.

[0033] In these examples, the battery pack 14 includes crossbeam assemblies 66 disposed between the cell stacks 30. The crossbeam assemblies 66 include vent passages and openings 70 to the vent passages. Vent byproducts vented through the vent opening 60 of one or more of the battery cells 50 can move into the vent passage through at least one of the openings 70. The gas and debris are passed through the vent passage to an area external to the battery pack 14 through a housing vent opening 74.

[0034] For example, the openings 70, the housing vent 74, or both may be covered by respective membranes when venting is not necessary. During venting, the venting byproducts may rupture the membranes, allowing the venting byproducts to flow from the battery cells 50 through the openings 70 to the vent passage and then through the housing vent 74. The example cross member assemblies 66 extend longitudinally in a direction parallel to the cell stack axes A. The cross member assemblies 66 and the cell stack axes A extend in a vehicle transverse direction (i.e., from a driver side to a passenger side).

[0035] The thermal management assemblies 54 can help direct venting byproducts outward relative to the respective cell stack axis A into the vent passages within the cross member assemblies 66. The thermal management assemblies 54 can help block movement of venting byproducts from one group of battery cells 50 to another group of battery cells 50. Thus, thermal energy associated with the venting byproducts is prevented from heating battery cells 50 in other groups and causing those battery cells 50 to vent.

[0036] Now with reference to Fig. 4-9 and with further reference to Fig. 2 and Fig. 3, the exemplary battery pack 14 includes a first type of thermal management assembly 54A ( Fig.4-6) and a second type of thermal management assembly 54B. The thermal management assemblies 54A separate and compartmentalize groups of battery cells 50. The thermal management assemblies 54B are disposed between the battery cells 50 of the groups.

[0037] The thermal management assemblies 54A include a thermal barrier 80 and a plurality of thermal blockers 84. The thermal barrier 80 includes an inserted region 88 and at least one protruding region 92. Within the cell stack 30, the inserted region 88 is inserted between the cells 50 and axially compressed, and the at least one protruding region 92 is located outside the inserted region 88 with respect to the cell stack axis A.

[0038] In the exemplary embodiment, the heat blockers 84 are secured to opposite axial sides of the protruding region 92 on a first outer side of the cell stack 30 and to opposite axial sides of the protruding region 92 on an opposite, second outer side of the cell stack 30.

[0039] In this example, two protruding regions 92 are used to support the heat blockers 84 on opposite sides of the cell stack 30. In other examples, the thermal management assembly could include a single protruding region on a horizontal side of the cell stack 30.

[0040] Furthermore, in another example, the thermal barriers 80 could instead or additionally be supported by at least one protruding region 92 located vertically above or below the cells 50. For the purposes of this disclosure, vertical and horizontal refer to the ground and orientation of the vehicle 10 during normal operation.

[0041] In this example, the thermal barriers 80 are mica-based films. In other examples, the thermal barriers 80 could be an aerogel film or a film comprising another thermally insulating material or a combination of thermally insulating materials. The thermal barrier 80 can extend to contact the housing assembly 34 and the crossbeam assemblies 66 to effectively compartmentalize groups of the battery cells 50.

[0042] An adhesive may be used to secure the heat blockers 84 to the protruding regions 92 of the thermal barrier 80. In this example, the adhesive is a piece of adhesive tape 96A. The thermal management assembly 54A includes a piece of double-sided adhesive tape 96A on a first axial side of the thermal barrier 80 and a piece of adhesive tape 96A on an opposite, second axial side of the thermal barrier 80. The pieces of adhesive tape 96A on each axial side of the thermal barrier 80 extend from the protruding region 92 on a first outer side to the protruding region 92 on an opposite, second outer side. In this example, the thermal barrier 80, along with the pieces of adhesive tape 96A, provide a base assembly for the thermal management assembly 54A.

[0043] The heat blockers 84 are secured to the protruding regions 92 of the thermal barrier 80 by portions of the adhesive tape 96A located on the protruding regions 92. Remaining portions of the adhesive tape 96A located within the inserted region 88 assist in bonding the battery cells 50 to the thermal barrier 80. The heat blockers 84 are made of foam in this example.

[0044] The thermal management assembly 54B includes the protruding regions 92 and the inserted region 88, but omits the thermal barrier 80. The thermal management assembly 54B includes a piece of adhesive tape 96B and a plurality of the heat blockers 84 secured to the adhesive tape 96B in the protruding regions 92. Within the inserted region, the piece of adhesive tape 96B is used to secure one of the battery cells 50 in the cell stack 30 to an axially adjacent battery cell 50 in the cell stack 30. The adhesive tape 96B alone provides a base assembly for the exemplary thermal management assembly 54B. This means that the base assembly is entirely provided by the adhesive tape 96B in the thermal management assembly 54B.

[0045] After assembly of the cell stacks 30, the cell stacks 30 include heat blockers 84 along opposite outer sides of the cell stacks 30. The battery cells 50 may include tab terminals (not shown) extending outwardly between axially adjacent heat blockers 84 for connection to one or more bus bar assemblies.

[0046] Features of the disclosed examples include thermal management assemblies that include a plurality of heat blockers. This can facilitate assembly because it may not be necessary to individually place heat blockers within the battery pack.

[0047] The foregoing description is exemplary and not restrictive in nature. Variations and modifications of the disclosed examples may occur to those skilled in the art without necessarily departing from the spirit of this disclosure. Accordingly, the scope of protection afforded by this disclosure can only be determined by reading the following claims.

Claims

[1] Traction battery pack assembly comprising: a housing assembly providing an interior space; a cell stack within the interior region, the cell stack comprising a plurality of battery cells arranged along a cell stack axis; and a thermal management assembly disposed along the cell stack axis, the thermal management assembly including a plurality of heat blockers secured to a base assembly, the base assembly including an inserted region and at least one protruding region, the inserted region disposed along the cell stack axis and inserted between a first and second battery cell, the at least one protruding region being located outside the inserted region with respect to the cell stack axis, the plurality of heat blockers being secured to the at least one protruding region of the base assembly. [2] The traction battery pack assembly of claim 1, wherein the plurality of battery cells comprises a plurality of pouch-style battery cells. [3] The traction battery pack assembly of claim 1, wherein the plurality of heat blockers includes heat blockers secured to opposite axial sides of the at least one protruding region on a first exterior side of the cell stack, and wherein the plurality of heat blockers optionally further includes heat blockers secured to opposite axial sides of the at least one protruding region on an opposite, second exterior side of the cell stack. [4] The traction battery pack assembly of claim 1, further comprising an adhesive securing the plurality of heat blockers to the at least one protruding region of the base assembly, and wherein the adhesive is optionally an adhesive tape. [5] The traction battery pack assembly of claim 4, wherein the base assembly includes a thermal barrier, wherein the adhesive tape includes a first piece of adhesive tape on a first axial side of the thermal barrier and a second piece of adhesive tape on an opposite, second axial side of the thermal barrier. [6] The traction battery pack assembly of claim 5, wherein the first piece of adhesive tape secures at least one heat blocker of the plurality of heat blockers on a first exterior side of the cell stack to the at least one protruding region and secures at least one other heat blocker of the plurality of heat blockers on an opposite, second exterior side of the cell stack to the at least one protruding region. [7] The traction battery pack assembly of claim 1, wherein the base assembly is entirely provided by an adhesive tape. [8] The traction battery pack assembly of claim 1, wherein the thermal management assembly is configured to prevent vent byproducts expelled from one or more battery cells on a first axial side of the thermal management assembly from moving adjacent to battery cells on an opposite, second axial side of the thermal management assembly. [9] The traction battery pack assembly of claim 1, wherein the base assembly is made of a first material and the plurality of heat blockers are made of a second, different material. [10] The traction battery pack assembly of claim 1, wherein the plurality of heat blockers are made of foam. [11] The traction battery pack assembly of claim 1, wherein the base assembly comprises mica. [12] A method for managing thermal energy of a battery pack, comprising: Supporting a plurality of heat blockers disposed on opposite sides of a cell stack within a housing assembly using a base assembly of a thermal management assembly, the base assembly being at least partially interposed between a first and a second battery cell of the cell stack. [13] A method of managing thermal energy of a battery pack as claimed in claim 12, further comprising adhesively securing the plurality of heat blockers to the base assembly, and optionally further comprising securing at least some of the heat blockers within the plurality of heat blockers on a first axial side of the base assembly using adhesive tape. [14] A method of managing thermal energy of a battery pack according to claim 13, further comprising securing the first battery cell to the first axial side of the base assembly using the adhesive tape, and optionally further comprising securing at least some of the heat blockers within the plurality of heat blockers to an opposite, second side of the base assembly using adhesive tape. [15] A method for managing thermal energy of a battery pack according to claim 14, wherein the base assembly is an adhesive tape.

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