Patent Application
20240039112
This disclosure relates generally to a traction battery pack and, in particular, to a method and apparatus for more evenly distributing vented gas away from a traction battery pack enclosure surface.
Electrified vehicles differ from conventional motor vehicles because electrified vehicles can be selectively driven using one or more electric machines powered by a traction battery pack. The electric machines can drive the electrified vehicles instead of, or in addition to, an internal combustion engine. A traction battery pack of an electrified vehicle can include one or more battery arrays within an enclosure. The battery arrays each include a plurality of individual battery cells.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the system includes at least one battery cell configured to provide a venting area to vent gases in response to a predetermined condition and an enclosure for the at least one battery cell. The enclosure has a surface that faces the venting area, and a plurality of textured forms are spaced across the surface to spread vented gas over the surface
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the plurality of textured forms comprise a plurality of pins.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the plurality of pins comprise discrete pins defined by a maximum outer dimension, and wherein the discrete pins are spaced apart from each other by a distance that is within a range of one to two times the maximum outer dimension.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the plurality of textured forms are comprised of a material that sublimates to a non-flammable gas when a threshold gas temperature is exceeded.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the material comprises epoxy, polyester, sheet molding compound, thermoplastic, glass fiber, or pentaerythritol phosphate.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the plurality of textured forms comprise a plurality of weaves.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the plurality of weaves are comprised of a ceramic, graphite, or metal material.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the plurality of textured forms comprise a plurality of ribs having a length that is greater than a width.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the plurality of ribs have a V-shape cross-section.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the plurality of textured forms are molded within the surface of the enclosure to extend outwardly toward the at least one battery cell.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the system includes a plurality of battery arrays within a traction battery pack, the battery arrays each having a plurality of individual battery cells, and at least one vent associated with one or more of the plurality of individual battery cells. The system further includes an enclosure for the traction battery pack, wherein the enclosure has an external surface and an internal surface that faces the at least one vent. A plurality of textured forms are spaced across the internal surface to more evenly distribute vented gas over the internal surface.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the plurality of textured forms comprise a plurality of discrete pins or ribs that are spaced apart from each other across the internal surface.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the plurality of textured forms comprise the plurality of pins which are each defined by a maximum outer dimension, and wherein the plurality of pins are spaced apart from each other by a distance that is within a range of one to two times the maximum outer dimension.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the plurality of textured forms comprise the plurality of ribs, and wherein each rib has a V-shape cross-section.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the plurality of textured forms are comprised of a material that sublimates to a non-flammable gas when a threshold gas temperature is exceeded.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the plurality of textured forms comprise a plurality of weaves that are comprised of a fiber based material.
In some aspects, the techniques described herein relate to a traction battery pack venting system, wherein the plurality of textured forms are molded within the internal surface of the enclosure to extend outwardly toward the at least one vent.
In some aspects, the techniques described herein relate to a traction battery pack venting method, the method including the step of: incorporating a plurality of textured forms spaced across an inner surface of a battery pack enclosure to spread gas vented by at least one battery cell more evenly over the inner surface.
In some aspects, the techniques described herein relate to a traction battery pack venting method, the method including forming the plurality of textured forms as pins, ribs, and/or weaves that are spaced apart from each other across the inner surface.
In some aspects, the techniques described herein relate to a traction battery pack venting method, the method including: forming the plurality of textured forms from a material that sublimates to a non-flammable gas when a threshold gas temperature is exceeded; and/or molding the plurality of textured forms within the internal surface of the enclosure to extend outwardly toward a vent of the at least one battery cell.
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 taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.
The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description. The figures that accompany the detailed description can be briefly described as follows:
Under some conditions, one or more battery cells of a traction battery pack can expel relatively high temperature gaseous byproducts. The gas byproducts can be expelled through vents of the battery cells as vented gases.
The vented gases can be relatively high temperature gases. During a venting event, thermal energy from the venting battery cells and the vented gases can be focused on one small area of a battery pack enclosure. This focus of thermal energy can be undesirable.
This disclosure is directed toward directing vented gases from the battery pack in ways that can reduce the focus of thermal energy on one small area and instead spread the thermal energy more evenly across an inner surface of the battery pack enclosure.
With reference to
The traction battery pack 12 can be a relatively high-voltage battery. The traction battery pack 12 is considered a traction battery pack at least because electrical energy from the traction battery pack 12 can be used to propel the electrified vehicle 10.
The traction battery pack 12 is, in the exemplary embodiment, secured to an underbody 18 of the electrified vehicle 10. The traction battery pack 12 could be located elsewhere on the electrified vehicle 10 in other examples. The traction battery pack 12 can be secured to the underbody 18 utilizing mechanical fasteners that engage structural rails of the electrified vehicle 10, for example. When secured to the underbody 18, a longitudinal axis A of the traction battery pack 12 is substantially aligned with a longitudinal axis V of the electrified vehicle 10.
The electrified vehicle 10 is an all-electric vehicle. In other examples the electrified vehicle 10 is a hybrid electric vehicle, which electively drives wheels using torque provided by an internal combustion engine instead of, or in addition to, torque provided by the electric machine 14 powered by the traction battery pack 12. Generally, the electrified vehicle 10 could be any type of vehicle having a traction battery pack 12.
With reference now to
In one example, the enclosure 20 comprises a bottom wall 24 that supports the battery arrays 22, and a pair of end walls 26 that are connected to each other by a pair of side walls 28 to form a box shape. A cover 30 is placed over the box-shaped structure to enclose the battery arrays 22 within the enclosure 20.
The individual battery arrays 22 each include a plurality of individual battery cells 32. In one example, the individual battery cells 32 each include a vent 34. When pressure within one of the battery cells 32 increases to a predetermined pressure level, that battery cell 32 will vent gas out of the cell 32 in a direction toward the cover 30, for example.
In another example, a group of two or more battery cells 32 may share a vent 34.
In another example, the vent 34 may be positioned to face the bottom wall 24, end walls 26, and/or side walls 28.
In another example, the vents 34 could be arranged to face a plurality of different walls 24, 26, 28 and/or the cover 30.
In another example, a battery cell may comprise a pouch style cell that may not have a defined vent; however, a perimeter seal of the pouch may open at any point around the perimeter to comprise a venting portion or venting area that vents gases in response to pressure reaching a predetermined level.
Gaseous byproducts and debris vented from one of the battery cells 32 moves through the vent 34 for that battery cell 32 and is typically expelled against a small sized area on the wall surface that faces the vent 34. The hot gas and debris may adversely affect the structure of the enclosure cover 30 due to ablative forces as the gas and debris are directed toward the same small area on the cover 30. The adverse effects can include perforation, rupture, matrix degradation, and delamination, for example. It is not desirable to thicken the enclosure cover and/or add an additional layer between the battery cells 32 and the cover 30 because of the limited packaging space and/or the possibility of trapping additional heat.
The subject disclosure comprises a traction battery pack venting system that provides a plurality of textured forms 40 that are spaced across an inner surface of the enclosure 20 to spread vented debris/gas over a wider area of the inner surface. Thus, instead of having kinetic and thermal energy focused at a small spot on the inner surface, the energy from the hot vent gas and debris is spread out over a greater area of the inner surface so that the above-described adverse effects are reduced. The vented gases can then be expelled from the enclosure 20 into an atmosphere around the electrified vehicle 10 using traditional methods if needed.
In one example shown in
In one example shown in
In another example shown in
In another example, the plurality of textured forms 40 comprise a plurality of ribs 50 that are used to deflect the gas and debris. In one example, each of the ribs 50 have a length that is greater than a width. In one example, the ribs 50 have a V-shaped cross-section. The orientation of the ribs 50 can be vertical, horizontal, or a combination of both. The ribs 50 can be formed as part of the cover 30 or added on to the cover 30. The ribs 50 can also be placed on other areas of the enclosure 20 dependent on which direction the vents 34 face.
In one example, the plurality of textured forms 40 are molded within the surface of the enclosure 20 itself to extend outwardly toward the vents 34 of the at least one battery cell 32. These molded structures can comprise the pins 32, weaves 48, and/or ribs 50 in any combination.
In another example, the plurality of textured forms 40 are comprised of a material that sublimates to a non-flammable gas when a threshold gas temperature is exceeded. The material comprises, for example, an epoxy, polyester, sheet molding compound (SMC), thermoplastic, glass fiber, pentaerythritol phosphate, or other similar material. The plurality of textured forms 40 made from this material can comprise pins, ribs, or weaves as described above. In this example, the textured forms 40 get sublimated to a non-flammable gas when their temperature exceeds a specific temperature threshold (e.g., 400° C.). As the sublimation takes place, some of the energy is absorbed while the gas and debris is also being deflected by the textured form itself.
The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. Thus, the scope of protection given to this disclosure can only be determined by studying the following claims.
