BATTERY PACK VENTING SYSTEM AND VENTING PROCEDURE

Abstract

A battery pack venting system comprises one or more cell stacks of a traction battery pack; and a venting management element having a partition separating an inner channel of the venting management element from an outer channel of the venting management element. The inner channel opens toward the cell stack. The inner channel is configured to communicate a stream of venting byproducts in a first direction to a location where the stream of venting byproducts can move around the partition from the inner channel to the outer channel. The outer channel is configured to communicate the stream of venting byproducts in an opposite, second direction to at least one outlet of the venting management element.

Description

AREA OF TECHNOLOGY

[0001] The present disclosure relates generally to traction battery packs and in particular to the communication of venting by-products from battery cells to an area outside the battery pack. GENERAL STATE OF THE ART

[0002] Electrified vehicles include a traction battery pack to supply power to electric motors and other electrical components within the vehicle. The traction battery pack can contain a variety of battery cells and various other internal components that support the electric vehicle's propulsion system. SUMMARY

[0003] In some aspects, the techniques described in this document relate to a battery pack venting system comprising: one or more cell stacks of a traction battery pack; and a venting management element having a partition separating an inner channel of the venting management element from an outer channel of the venting management element, the inner channel opening towards the cell stack, the inner channel configured to communicate a stream of venting by-products in a first direction to a position where the stream of venting by-products can move around the partition from the inner channel to the outer channel, the outer channel configured to communicate the stream of venting by-products in an opposite, second direction to at least one outlet from the venting management element.

[0004] In some aspects, the techniques described in this document relate to a battery pack venting system, with the inner channel being located between the outer channel and the one or more cell stacks.

[0005] In some aspects, the techniques described in this document relate to a battery pack venting system, wherein the inner channel is configured to receive a stream of venting by-products from an area between a pair of crossbeam assemblies.

[0006] In some aspects, the techniques described in this document relate to a battery pack venting system, where the venting management element is an extruded structural element.

[0007] In some aspects, the techniques described in this document relate to a battery pack venting assembly, where the venting management element extends over a multitude of cell stacks.

[0008] In some aspects, the techniques described in this document relate to a battery pack venting system, wherein the venting management element extends longitudinally along an axis of the venting management element, with the first direction and the second direction extending along the axis of the venting management element.

[0009] In some aspects, the techniques described in this document relate to a battery pack venting system which further includes a first end cap and a second end cap located at opposite axial ends of the venting management element, the first end cap and the second end cap each being configured to divert a stream of venting by-products from the inner channel to the outer channel.

[0010] In some aspects, the techniques described in this document relate to a battery pack venting system, where the inner channel has a C-shaped profile.

[0011] In some aspects, the techniques described in this document relate to a battery pack venting system, with the inner duct located inside the outer duct.

[0012] In some aspects, the techniques described in this document relate to a battery pack venting system, with the outlet located on a vertical underside of the venting management element.

[0013] In some aspects, the techniques described in this document relate to a battery pack venting system, where one or more cell stacks are cell stacks of the upper layer of a multi-layer battery pack.

[0014] In some aspects, the techniques described in this document relate to a battery pack venting system, where the outlet opens vertically downwards.

[0015] In some aspects, the techniques described in this document relate to a battery pack venting system, further comprising a vent opening in a housing wall of the traction battery pack, wherein the vent opening is configured to communicate the flow of venting by-products received from the outlet to an area outside the traction battery pack.

[0016] In some aspects, the techniques described in this document relate to a battery pack venting assembly, where the vent opening is a valve.

[0017] In some aspects, the techniques described in this document relate to a battery pack venting procedure that includes: communicating a stream of venting byproducts from one or more battery cells to the outside into an internal channel of a venting management element and against a partition of the venting management element; communicating the stream of venting byproducts through the internal channel in a first direction; diverting the stream of venting byproducts into an external channel; and communicating the stream of venting byproducts through the external channel in a second direction to an outlet from the venting management element, the second direction being opposite to the first direction.

[0018] In some aspects, the techniques described in this document relate to a battery pack venting procedure, furthermore involving the communication of the flow of venting by-products vertically downwards through the outlet.

[0019] In some aspects, the techniques described in this document relate to a battery pack venting procedure, further involving the communication of the flow of venting by-products that have passed through the outlet, through a vent opening in a battery pack housing, in order to discharge the flow of venting by-products from a battery pack.

[0020] In some aspects, the techniques described in this document relate to a battery pack venting procedure, wherein the one or more battery cells are located in an upper layer of battery packs in a multi-layer battery pack.

[0021] In some aspects, the techniques described in this document relate to a battery pack venting method, where the inner channel has a C-shaped cross-sectional profile.

[0022] The embodiments, examples, and alternatives described in the preceding paragraphs, the claims, or the following description and drawings, which may include any of their various aspects or individual features, can be considered independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, provided such features are not incompatible. BRIEF DESCRIPTION OF THE FIGURES

[0023] The various features and advantages of the disclosed examples will be apparent to the person skilled in the art from the detailed description. The figures accompanying the detailed description can be briefly described as follows: Fig. Figure 1 illustrates a side view of an electrified vehicle having a battery pack according to an exemplary embodiment of the present disclosure. Fig. Figure 2 illustrates a perspective and partially expanded view of selected sections of the battery pack. Fig. 1. Fig. Figure 3 illustrates a schematic top view of the battery pack made of Fig. 2. Fig. Figure 4 illustrates a sectional view along line 4-4 in Fig. 3. Fig. Figure 5 illustrates a perspective view of a venting management element from the battery pack. Fig. 2. Fig. Figure 6 illustrates another perspective view of the in Fig. 5 ventilation management elements shown. Fig. Figure 7 illustrates a sectional view along line 7-7 in Fig. 6. DETAILED DESCRIPTION

[0024] This disclosure describes in detail exemplary systems and methods used to communicate venting byproducts from battery cells to an area outside the battery pack. The systems and methods involve communicating the venting byproducts in ways that extend the time the byproducts remain within the battery pack before being discharged. Increasing the time the byproducts spend within the battery pack can help reduce the thermal energy contained within the byproducts before they are discharged. These and other features are discussed in more detail in the following paragraphs.

[0025] Fig. Figure 1 schematically illustrates an electrified vehicle 10. The electrified vehicle 10 can include any type of electrified powertrain. In one embodiment, the electrified vehicle 10 is a battery electric vehicle (BEV). However, the concepts described herein are not limited to BEVs and could extend to other electrified vehicles, including, but not limited to, hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles, etc. Therefore, although not specifically shown in the exemplary embodiment, the powertrain of the electrified vehicle 10 could be equipped with an internal combustion engine, which can be used either alone or in combination with other power sources to propel the electrified vehicle 10.

[0026] In the illustrated embodiment, the electrified vehicle 10 is depicted as an automobile. However, the electrified vehicle 10 could alternatively be a sport utility vehicle (SUV), a van, a pickup truck, or any other vehicle configuration. Although the figures in this disclosure illustrate a specific relationship between the components, these illustrations are not intended to limit the scope of this disclosure. The placement and orientation of the various components of the electrified vehicle 10 are shown schematically and could vary within the scope of this disclosure. Furthermore, the various figures accompanying this disclosure are not necessarily drawn to scale, and some features may be enlarged or reduced to highlight certain details of a particular component, assembly, or system.

[0027] In the illustrated embodiment, the electrified vehicle 10 is a fully electric vehicle powered exclusively by electrical power, such as from one or more electric machines 12, without assistance from an internal combustion engine. The electric machine 12 can operate as an electric motor, an electric generator, or both. The electric machine 12 receives electrical power and can convert this power into torque to drive one or more wheels 14 of the electrified vehicle 10.

[0028] A voltage bus 16 electrically couples the electric machine 12 to a traction battery pack 18. The traction battery pack 18 is an exemplary battery of an electrified vehicle. The traction battery pack 18 can be a high-voltage traction battery pack assembly comprising a multitude of battery cells capable of outputting electrical power to supply the electric machine 12 and / or other electrical consumers of the electrified vehicle 10. Alternatively or additionally, other types of energy storage devices and / or output devices could also be used to supply the electrified vehicle 10 with electrical power.

[0029] The traction battery pack 18 is secured to an underbody 20 of the electrified vehicle 10. However, in other examples, the traction battery pack 18 could be located at a different location on the electrified vehicle 10.

[0030] With reference to the Fig. 2-4 The traction battery pack 18 comprises a multitude of cell stacks 22, which are housed within an inner compartment 30 of a casing. Here, the cell stacks 22 fit into a casing shell 34, which can be secured to a casing cover 36, the bottom 20, or both, to enclose the cell stacks 22 and other battery-internal components within the inner compartment 30.

[0031] Each cell stack 22 contains a multitude of battery cells 38, which are stacked side by side along a respective cell stack axis A. The battery cells 38 store and deliver electrical power to supply various components of the electrified vehicle 10.

[0032] In this embodiment, the battery cells are 38 lithium-ion battery cells in pouch form. However, within the scope of protection of the present disclosure, alternatively battery cells with other geometries (cylindrical, prismatic, etc.) and / or chemical compositions (nickel-metal hydride, lead-acid, etc.) could be used.

[0033] The cell stacks 22 can additionally include separators, thermally conductive materials, adhesives, and other materials between the individual battery cells 38. Although a specific number of cell stacks 22 is illustrated in the various figures of the present disclosure, the traction battery pack 18 could include any number of cell stacks 22.

[0034] In this example, the battery cells 38 of each cell stack 22 are positioned between a pair of crossbeam assemblies 42, such that the battery cells 38 are located along the crossbeam assemblies 42. The crossbeam assemblies 42 described in this document are configured to increase the structural integrity of the traction battery pack 18.

[0035] In one embodiment, the cell stacks 22 and the crossbeam assemblies 42 extend longitudinally in a transverse direction of the electrified vehicle 10. However, other configurations are also conceivable within the scope of protection of the present disclosure.

[0036] From time to time, pressure and thermal energy within at least one of the battery cells 38 in the cell stacks 22 may increase. This can cause the battery cell 38 to discharge a stream of venting byproducts, which may include gas and dirt. The venting byproducts can be discharged from the battery cell 38 through a designated cell vent within a housing of the battery cell 38. The cell vent may be a membrane that yields in response to increased pressure and thermal energy within the battery cell 38. The cell vent may also be a fractured area of ​​the associated battery cell 38.

[0037] In this example, the battery pack 18 comprises an upper layer 46 of cell stacks 22 and a lower layer 50 of cell stacks 22. The upper layer 46 is located vertically above the lower layer 50. "Vertical" in the context of this disclosure refers to the general orientation of the battery pack 18 relative to the ground when installed inside a vehicle. Since the battery pack 18 comprises both the upper layer 46 and the lower layer 50, it can be considered a multi-layered battery pack.

[0038] Within the interior space 30, the upper layer 46 can be supported on a platform 54. A structural element 58 extends over the ends of the cell stacks 22 of the lower layer 50. One of the structural elements 58 is located on the driver's side of the cell stacks 22 on the lower layer 50. Another structural element 58 is located on the passenger's side of the cell stacks 22 on the lower layer 50. Open areas 62 are provided between the structural elements 58 and their respective side walls of the housing shell 34.

[0039] A vent opening 66 extends through the wall of the housing shell 34. Venting byproducts within the open area 62 can be discharged from the battery pack 18 through the vent opening 66. The vent opening 66 can be a valve. In another example, the vent opening 66 is a pop-off vent.

[0040] Vent management elements 70 span the cell stacks 22 of the upper layer 46. One of the vent management elements 70 is located on the driver's side of the battery cells 38 in the upper layer 46. Another of the vent management elements 70 is located on the passenger's side of the cell stacks 22 in the upper layer 46. The vent management elements 70 can be considered cell vent management (CVM) covers.

[0041] Not referring to the Fig. 5-7 and with further reference to the Fig. In this example, the venting management element 70 forms an inner channel 74 and an outer channel 78. The exemplary inner channel 74 opens towards the cell stacks 22. The inner channel 74 generally has a C-shaped cross-sectional profile, as shown in Fig. Figure 4 shows the outer channel 78 having an O-shaped profile. The inner channel 74 is located inside the outer channel 78.

[0042] A partition 82 separates the inner channel 74 from the outer channel 78. In this example, the partition 82 does not extend over the entire length of the venting management element 70. Thus, the inner channel 74 opens to the outer channel 78 at opposite axial ends of the venting management element 70 around the axial ends of the partition 82. The end walls 84 enclose each axial end of the venting management element 70.

[0043] The venting management element 70 can be made of anodized aluminum. In one example, the venting management element 70 is extruded, or sections of the venting management element 70 are extruded.

[0044] In some examples, to simplify the manufacture of the vent management element 70, the vent management element 70 could be end caps 80 (see dashed lines in Fig. 7) at the axial ends of the venting management element 70. The end caps 80 can provide the end walls 84 that enclose the axial ends and facilitate the diversion of the venting by-products V from the inner duct 74 to the outer duct 78. The partition 82 can be omitted from the end caps 80, so that the inner duct 74 opens to the outer duct 78 at the opposite axial ends of the venting management element 70. The end caps 80 could be attached to the other sections of the venting management element 70. A person skilled in the art, benefiting from the present disclosure, could potentially develop other ways of diverting venting by-products from the inner duct 74 to the outer duct 78.

[0045] A barrier – in this case a mica film 86 – is arranged in a sandwich-like fashion between the venting management element 70 and the cell stacks 22 on the upper layer 46. In this example, venting byproducts V from the battery cells 38 of the upper layer 46 are first diverted through openings in the crossbeam assemblies 42 into an open area 90 between the crossbeam assemblies 42. The venting byproducts V then flow outwards from a centerline of the vehicle 10 towards the mica film 86.

[0046] In other examples, the cell stacks 22 could be oriented differently, and the crossbeam assemblies 42 could be omitted. For example, the cell stacks 22 could contain cells 38 arranged along an axis parallel to a longitudinal axis of the venting management element 70. The cells 38 could be vented directly outwards into the inner channel 74 instead of through the crossbeam assembly 42 into an open area between the cell stacks 22. In such an example, the venting management element 70 could be connected to end plates of the cell stacks 22.

[0047] The venting byproducts V can lift a flap or tear open an area of ​​the mica foil 86 and move into the inner channel 74. The venting byproducts V moving outwards into the inner channel 74 eventually contact the partition 82 and are redirected in a first direction D1 or a second direction D2 along a longitudinal axis of the venting management element 70. In this example, the first direction D1 is a forward direction within the vehicle 10, and the second direction D2 is a direction towards the rear of the vehicle 10.

[0048] The venting byproducts V, moving in the first direction D1 or the second direction D2, eventually reach the end wall 84. At this position, the venting byproducts V are redirected and guided around the axial ends of the partition 82 into the outer channel 78. The venting byproducts V then flow through the outer channel 78 in the opposite direction. That is, the flow that moved through the inner channel 74 in the first direction D1 is redirected by the end wall 84 into the outer channel 78 and then flows through the outer channel 78 in the second direction D2.

[0049] The venting byproducts V flow through the outer channel 78 and eventually reach an outlet 94 from the outer channel 78 and from the venting management element 70. In this example, the outlet 94 is an opening in a downward-facing side 96 of the venting management element 70. The outlet 94 opens to the open area 62 between the structural element 58 and the wall of the shell 34. The venting byproducts V, having passed through the outlet 94, move vertically downward into the open area 62. Once in the open area 62, the venting byproducts V can exit the battery pack 18 through the vent opening 66.

[0050] The thermal energy in the venting byproducts V is dissipated as they move through the inner channel 74 and the outer channel 78 of the venting management element 70. In this example, the anodized aluminum material of the venting management element 70 can act as a heat sink to facilitate the transfer of thermal energy from the venting byproducts V. When the venting byproducts V are guided through the venting management element 70 in multiple directions, the time before they exit the battery pack 18 is extended, and the thermal energy in these byproducts V is given additional time to dissipate before being released from the battery pack 18 through the vent opening 66. Thus, by the time the venting byproducts V exit the battery pack 18, their temperature has been reduced.Due to the multiple diversions of the venting by-products V, the venting by-products V can be characterized as moving along a winding path through the battery pack 18.

[0051] Features of the disclosed examples include extending the time during which the venting byproducts move through a battery pack before the venting byproducts are removed from the battery pack.

[0052] The preceding description is exemplary and not limiting. Variations and modifications of the disclosed examples may be apparent to a person skilled in the art, which do not necessarily deviate from the core of this disclosure. Therefore, the scope of protection granted by this disclosure can only be determined by reading the following patent claims.

Claims

[1] Battery pack venting system, comprising the following: one or more cell stacks of a traction battery pack; and A venting management element comprising a partition separating an inner channel of the venting management element from an outer channel of the venting management element, wherein the inner channel opens towards the cell stack, wherein the inner channel is configured to communicate a stream of venting by-products in a first direction to a position where the stream of venting by-products can move around the partition from the inner channel to the outer channel, wherein the outer channel is configured to communicate the stream of venting by-products in an opposite, second direction to at least one outlet from the venting management element. [2] Battery pack venting system according to claim 1, wherein the inner channel is arranged between the outer channel and the one or more cell stacks. [3] Battery pack venting system according to claim 1, wherein the inner channel is configured to receive a stream of venting by-products from a region between a pair of crossbeam assemblies. [4] Battery pack venting system according to claim 1, wherein the venting management element is an extruded structural element. [5] Battery pack venting system according to claim 1, wherein the venting management element extends over a plurality of cell stacks. [6] Battery pack venting system according to claim 1, wherein the venting management element extends longitudinally along an axis of the venting management element, the first direction and the second direction extending along the axis of the venting management element. [7] Battery pack venting system according to claim 1, further comprising a first end cap and a second end cap arranged at opposite axial ends of the venting management element, wherein the first end cap and the second end cap are each configured to divert a flow of venting by-products from the inner channel to the outer channel. [8] Battery pack venting system according to claim 1, wherein the inner channel is located inside the outer channel and optionally wherein the inner channel has a C-shaped profile. [9] Battery pack venting system according to claim 1, wherein the outlet is located on a vertical underside of the venting management element. [10] Battery pack venting system according to claim 1, wherein one or more cell stacks are cell stacks of the upper layer of a multilayer battery pack and optionally wherein the outlet opens vertically downwards. [11] Battery pack venting system according to claim 10, further comprising a vent opening in a housing wall of the traction battery pack, wherein the vent opening is configured to communicate the flow of venting by-products received from the outlet to an area outside the traction battery pack, and optionally wherein the vent opening is a valve. [12] Battery pack venting procedure, comprising the following: Communicating a stream of venting by-products from one or more battery cells to the outside into an internal channel of a venting management element and against a partition of the venting management element; Communicating the flow of venting by-products through the inner duct in a first direction; Diverting the flow of venting byproducts into an external duct; and Communicating the flow of venting by-products through the external duct in a second direction to an outlet from the venting management element, the second direction being opposite to the first direction. [13] Battery pack venting method according to claim 12, further comprising communicating the flow of venting by-products vertically downwards through the outlet and optionally further comprising communicating the flow of venting by-products that have passed through the outlet through a vent opening in a battery pack housing to discharge the flow of venting by-products from a battery pack. [14] Battery pack venting system according to claim 12, wherein the one or more battery cells are located in an upper layer of battery packs in a multi-layer battery pack. [15] Battery pack venting method according to claim 12, wherein the inner channel has a C-shaped cross-sectional profile.

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