Battery pack exhaust assembly and exhaust method

Abstract

The invention provides a battery pack venting assembly and a venting method. A battery pack venting assembly includes: a battery pack housing assembly providing a battery pack interior; and a stack of cells within the interior of the battery pack. Each cell stack includes a plurality of battery cells. A module housing assembly is also within the battery pack interior. Each of the module housing assemblies accommodates one or more of the cell stacks. The exhaust manifold penetrates through the battery pack shell assembly from the interior of the battery pack and extends to the area outside the interior of the battery pack. Exhaust branches within the battery pack interior each extend from one of the module housing assemblies to the exhaust manifold.

Description

Technical Field

[0001] The present disclosure generally relates to venting exhaust by-products from a traction battery pack. Background Art

[0002] Electrified vehicles differ from conventional motor vehicles in that electrified vehicles use one or more electric motors powered by a traction battery to selectively drive. The electric motor(s) can drive the electrified vehicle in place of or in addition to an internal combustion engine. Example electrified vehicles include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles (FCVs), and battery electric vehicles (BEVs).

[0003] Referring to FIG. 1, a prior art battery pack 2 includes a plurality of battery cell groups 4 disposed inside an outer housing 6. If a battery cell in one of the groups 4 vents, the venting by-products are released into the interior of the outer housing 6. Inside the outer housing 6, the venting by-products can flow adjacent to other battery cell groups 4 before reaching an area outside the outer housing 6 through a vent port 8. Summary of the Invention

[0004] In some aspects, the techniques described herein relate to a battery pack venting assembly that includes: a battery pack outer housing assembly that provides an interior of the battery pack; a plurality of cell stacks inside the interior of the battery pack, each cell stack including a plurality of battery cells; a plurality of module outer housing assemblies inside the interior of the battery pack, each of the module outer housing assemblies housing one or more of the cell stacks; an exhaust manifold that extends from the interior of the battery pack through the battery pack outer housing assembly to an area outside the interior of the battery pack; and a plurality of exhaust branches inside the interior of the battery pack, each of the exhaust branches extending from one of the module outer housing assemblies to the exhaust manifold.

[0005] In some aspects, the techniques described herein relate to a battery pack venting assembly in which the exhaust branches each lead to the exhaust manifold inside the interior of the battery pack.

[0006] In some aspects, the techniques described herein relate to a battery pack venting assembly in which the exhaust branches are each configured to convey venting by-products directly from one of the module outer housing assemblies to the exhaust manifold.

[0007] In some aspects, the techniques described herein relate to a battery pack venting assembly in which the exhaust manifold is configured to convey venting by-products received from one or more of the exhaust branches to an area outside the battery pack outer housing assembly.

[0008] In some aspects, the techniques described herein relate to a battery pack exhaust assembly, wherein the module housing assembly, the exhaust branch, and the exhaust manifold are sealed such that within the battery pack, exhaust by-products are contained by the module housing assembly, the exhaust branch, and the exhaust manifold.

[0009] In some aspects, the techniques described herein relate to a battery pack exhaust assembly, wherein the cell stack is immersion cooled.

[0010] In some aspects, the techniques described herein relate to a battery pack exhaust assembly, which further includes a plurality of coolant inlet branches, each of the coolant inlet branches being configured to convey a liquid coolant to one of the module housing assemblies.

[0011] In some aspects, the techniques described herein relate to a battery pack exhaust assembly, which further includes a coolant inlet manifold that conveys a liquid coolant to each of the plurality of coolant inlet branches.

[0012] In some aspects, the techniques described herein relate to a battery pack exhaust assembly, wherein the coolant inlet branch is directly connected to the coolant inlet manifold within the battery pack.

[0013] In some aspects, the techniques described herein relate to a battery pack exhaust assembly, wherein the plurality of exhaust branches are configured to convey a liquid coolant and exhaust by-products directly from one of the module housing assemblies to the exhaust manifold.

[0014] In some aspects, the techniques described herein relate to a battery pack exhaust assembly, wherein the battery cells are each configured to exhaust into a liquid coolant.

[0015] In some aspects, the techniques described herein relate to a battery pack exhaust assembly, which further includes a plurality of check valves that prevent exhaust by-products from flowing back from the exhaust manifold through the exhaust branches.

[0016] In some aspects, the techniques described herein relate to a method of exhausting from a battery pack, which includes: within the battery pack provided by a battery pack housing assembly, conveying exhaust by-products from a battery module housing assembly into an exhaust branch, the exhaust by-products being discharged from at least one battery cell within a cell stack housed within the battery pack; within the battery pack, conveying the exhaust by-products through the exhaust branch into an exhaust manifold; and conveying the exhaust by-products through the exhaust manifold, through the battery pack housing, to an area external to the battery pack housing to discharge the exhaust by-products from the battery pack housing.

[0017] In some aspects, the techniques described herein relate to a method in which the module housing assembly, the exhaust branch, and the exhaust manifold are sealed such that, within the battery pack, exhaust by-products are contained by the module housing assembly, the exhaust branch, and the exhaust manifold.

[0018] In some aspects, the techniques described herein relate to a method in which the battery module housing assembly is one of a plurality of battery module housing assemblies within the battery pack housing assembly.

[0019] In some aspects, the techniques described herein relate to a method in which each of the battery module housing assemblies includes at least one cell stack having a plurality of battery cells.

[0020] In some aspects, the techniques described herein relate to a method in which the cell stacks each include a plurality of individual battery cells configured to exhaust into a liquid coolant.

[0021] In some aspects, the techniques described herein relate to a method that further includes using an immersion thermal management system to manage thermal energy within the battery pack.

[0022] In some aspects, the techniques described herein relate to a method that further includes: conveying a liquid coolant through a coolant inlet manifold into the battery pack; and conveying the liquid coolant from the coolant inlet manifold to one of the plurality of battery module housing assemblies through one of a plurality of coolant inlet branches.

[0023] In some aspects, the techniques described herein relate to a method in which the exhaust branch is one of a plurality of exhaust branches, each of the exhaust branches connects one of the battery housing modules to the exhaust manifold, and the method further includes conveying both the exhaust by-products and the liquid coolant to the exhaust manifold through one of the exhaust branches.

[0024] The embodiments, examples, and alternatives of the foregoing paragraphs, claims, or the following description and drawings may be employed independently or in any combination, including any one of their various aspects or corresponding individual features. Features described in connection with one embodiment apply to all embodiments unless such features are incompatible. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In accordance with the detailed description, the various features and advantages of the disclosed examples will become apparent to those skilled in the art. The accompanying drawings, which are incorporated in and constitute a part of the detailed description, may be briefly described as follows:

[0026] FIG. 1 shows a schematic diagram of a prior art battery pack.

[0027] Figure 2 A side view of an electrified vehicle having a traction battery pack is shown.

[0028] Figure 3 A perspective and partial cross-sectional view of a battery pack in accordance with an exemplary aspect of the present disclosure is shown.

[0029] Figure 4 Shown is Figure 3 a schematic top view of the battery pack.

[0030] Figure 5 A schematic top view of a battery pack in accordance with another exemplary aspect of the present disclosure is shown. DETAILED DESCRIPTION

[0031] The present disclosure generally relates to a traction battery pack for an electrified vehicle and, more particularly, to venting exhaust by-products from within the traction battery pack.

[0032] Referring Figure 2 to, electrified vehicle 10 includes a traction battery pack 12, an electric motor 14, and wheels 16. Battery pack 12 powers electric motor 14, which converts electrical energy into torque to drive wheels 16. Battery pack 12 is a traction battery pack because battery pack 12 is used for propulsion.

[0033] In an exemplary embodiment, battery pack 12 is secured to the underside of the body of electrified vehicle 10. In other examples, battery pack 12 may be located elsewhere on electrified vehicle 10.

[0034] Exemplary vehicle 10 is a battery electric vehicle (BEV). In another example, vehicle 10 may be another type of electrified vehicle, such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or a conventional vehicle. A hybrid electric vehicle selectively drives the wheels using torque provided by an internal combustion engine (as an alternative to or in addition to the electric motor). Generally, electrified vehicle 10 may be any type of vehicle having a traction battery pack.

[0035] Now referring Figure 3 and Figure 4 , battery pack 12 includes a battery pack housing assembly 18 and a plurality of battery modules 20 housed within interior 24 of battery pack housing assembly 18. Each of battery modules 20 includes a module housing assembly 32 and a stack of battery cells 36 housed within the module housing assembly. Stack of battery cells 36 includes a plurality of individual battery cells 40.

[0036] In this example, each of module housing assemblies 32 houses a single stack of battery cells 36. In other examples, module housing assembly 32 may hold more than one stack of battery cells 36.

[0037] A plurality of exhaust branches 44 and an exhaust manifold 48 are also disposed within the interior 24. One of the exhaust branches 44 is connected to each of the module housing assembly 32 and the exhaust manifold 48. In other examples, two or more exhaust branches 44 may be connected to each of the module housing assemblies 32. The module housing assembly 32 is sealed such that the exhaust branch 44 is the only flow path from the module housing assembly 32.

[0038] If exhaust by-products are released from one or more of the battery cells 40, the exhaust by-products can be released from the battery cells 40 through the vent 52. An increase in pressure within one of the battery cells 40 can cause the vent 52 to rupture, thereby forming a path for the exhaust by-products to be released from within the battery cell 40.

[0039] After the exhaust by-products pass through the vent 52, the exhaust by-products are initially contained within the interior of the module housing assembly 32. Then, the exhaust by-products can move out of the interior of the module housing assembly 32 from the module housing assembly 32 through the exhaust branches 44. In this example, the exhaust branches 44 each extend from one of the module housing assemblies 32 to the exhaust manifold 48.

[0040] The exhaust branches 44 convey the exhaust by-products from the module housing assembly 32 to the exhaust manifold 48. The exhaust branches 44 lead to the exhaust manifold 48 within the interior 24 of the battery pack. The exhaust manifold 48 conveys the exhaust by-products received from the exhaust branches 44 through the battery pack housing assembly 18 to an area external to the battery pack housing assembly 18.

[0041] Thus, the exhaust by-products are contained within the module housing assembly 32 having one or more battery cells 40 that are venting, the exhaust branches 44 connected to the module housing assembly 32, and the exhaust manifold 48 until the exhaust by-products are discharged or expelled from the battery pack 12. The exhaust by-products are not released into other areas within the interior 24 of the battery pack 12. This helps to mitigate the transfer of thermal energy to the battery modules 20 that are not venting.

[0042] Within the interior 24, the exhaust branches 44 are configured to convey the exhaust by-products to the exhaust manifold 48. Each of the exhaust branches 44 may include a check valve 56 that prevents the exhaust by-products discharged from one of the battery modules 20 from flowing back through the exhaust branch 44 into the module housing assembly 32 of another battery module 20 that does not contain a battery cell 40 that is venting.

[0043] Introducing the exhaust by-products into the exhaust manifold 48 within the battery pack housing assembly 18 can simplify discharging the exhaust by-products to an area external to the battery pack housing assembly 18. For example, only a single outlet through the battery pack housing assembly 18, rather than an outlet for each exhaust branch 44.

[0044] Now refer to Figure 5 In a variation of the example disclosed above, multiple battery modules 120 are included within the battery pack enclosure assembly 118 of the battery pack 112. An immersion thermal management system is used to manage the thermal energy within the battery modules 120.

[0045] In this example, multiple coolant inlet branches 160 are configured to convey liquid coolant from the coolant inlet manifold 164 to a respective one of the battery modules 120. The liquid coolant can be used to manage the thermal energy within the battery modules 120.

[0046] If the battery cells 140 of the cell stack 136 within the battery module 120 begin to vent, the venting by-products are discharged from the battery cells 140, and the battery cells directly vent into the coolant within the module enclosure assembly 132 of the battery module 120 having the positively venting battery cells 140.

[0047] Then, the mixture of the venting by-products and the coolant can be conveyed through the associated exhaust branch 144 to the exhaust manifold 148. The exhaust manifold 148 discharges the mixture of the venting by-products and the coolant to an area external to the battery pack enclosure assembly 118. A check valve ( Figure 5 not shown in the figure) can be used to prevent the venting by-products from flowing back from the exhaust branch 144 into the module enclosure assembly 132. Check valves can also be added to the coolant inlet branches 160, the coolant inlet manifold 164, or both. These check valves can prevent the backflow of gas / particles / fluids during cell venting (especially during the initial pressure increase).

[0048] In Figure 5 the example, the liquid coolant moves within the module enclosure assembly 132 along a flow path that is parallel to the orientation of the battery cells 140 within the cell stack 136. In other examples, the flow path can be oriented differently, such as perpendicular to the longitudinal axis of the cell stack.

[0049] Features of the disclosed example include substantially sealing individual cell stacks within respective module enclosure assemblies, which are disposed within a larger battery pack enclosure assembly. The individual module enclosure assemblies can contain the venting by-products from the cells within the module enclosure assemblies and convey those venting by-products to an area external to the battery pack enclosure through exhaust branches and an exhaust manifold. When the cell stacks are contained within the module enclosure assemblies, the venting by-products cannot freely move to positions adjacent to other battery modules within the battery pack.

[0050] The foregoing description is exemplary in nature and not restrictive. Variations and modifications to the disclosed examples may become apparent to those skilled in the art, and such variations and modifications do not necessarily depart from the essence of the disclosure. Accordingly, the scope of protection conferred upon the disclosure can only be determined by studying the appended claims.

Claims

1. A battery pack exhaust assembly, comprising: a battery pack housing assembly, the battery pack housing assembly providing a battery pack interior; A plurality of battery cell stacks within the battery pack, each battery cell stack comprising a plurality of battery cells; a plurality of module housing assemblies within the interior of the battery pack, each of the module housing assemblies accommodating one or more of the battery cell stacks; an exhaust manifold extending from the interior of the battery pack through the battery pack housing assembly to an area outside the interior of the battery pack; as well as A plurality of exhaust branches within the interior of the battery pack, each of the exhaust branches extending from one of the module housing assemblies to the exhaust manifold.

2. The battery pack exhaust assembly as claimed in claim 1, wherein the exhaust branches each lead to the exhaust manifold inside the battery pack.

3. The battery pack vent assembly of claim 1, wherein the exhaust branches are each configured to convey exhaust byproducts from one of the module housing assemblies directly to the exhaust manifold.

4. The battery pack vent assembly of claim 1, wherein the exhaust manifold is configured to transmit exhaust byproducts received from one or more of the exhaust branches to an area external to the battery pack housing assembly.

5. The battery pack exhaust assembly of claim 1, wherein the module housing assembly, the exhaust branch, and the exhaust manifold are sealed so that within the interior of the battery pack, exhaust byproducts are contained by the module housing assembly, the exhaust branch, and the exhaust manifold.

6. The battery pack venting assembly of claim 1, wherein the battery cell stack is immersion cooled, and optionally.

7. The battery pack exhaust assembly of claim 1 , further comprising a plurality of coolant inlet branches, each of the coolant inlet branches being configured to deliver liquid coolant to one of the module housing assemblies, and optionally, wherein the plurality of exhaust branches are configured to deliver liquid coolant and exhaust byproducts from one of the module housing assemblies directly to the exhaust manifold.

8. The battery pack vent assembly of claim 7, further comprising a coolant inlet manifold that delivers liquid coolant to each of the plurality of coolant inlet branches, and optionally, wherein the coolant inlet branches are directly connected to the coolant inlet manifold within the interior of the battery pack.

9. The battery pack venting assembly of claim 1, further comprising a plurality of check valves, the plurality of check valves preventing exhaust byproducts from flowing back from the exhaust manifold through the exhaust branch.

10. A method for venting air from a battery pack, comprising: within a battery pack interior provided by a battery pack housing assembly, conveying exhaust byproducts from a battery module housing assembly into an exhaust branch, the exhaust byproducts being exhausted from at least one battery cell within a battery cell stack housed within the battery pack interior; In the battery pack, the exhaust byproducts are transmitted to an exhaust manifold through the exhaust branch; as well as The exhaust byproducts are conveyed through the exhaust manifold, through the battery pack housing, to an area outside the battery pack housing to exhaust the exhaust byproducts from the battery pack housing.

11. The method of claim 10, wherein the module housing assembly, the exhaust branch, and the exhaust manifold are sealed such that within the interior of the battery pack, exhaust byproducts are contained by the module housing assembly, the exhaust branch, and the exhaust manifold.

12. The method of claim 10, wherein the battery module housing assembly is one of a plurality of battery module housing assemblies within the battery pack housing assembly.

13. The method of claim 12, wherein each of the battery module housing assemblies comprises at least one cell stack having a plurality of individual battery cells, and optionally wherein the cell stacks each comprise a plurality of battery cells configured to vent into a liquid coolant.

14. The method of claim 12, further comprising managing thermal energy within the interior of the battery pack using an immersion thermal management system.

15. The method of claim 14, further comprising: delivering liquid coolant into the interior of the battery pack through a coolant inlet manifold; and delivering the liquid coolant from the coolant inlet manifold to the plurality of battery module housings through one of a plurality of coolant inlet branches, and optionally, wherein the exhaust branch is one of a plurality of exhaust branches, each of the exhaust branches connecting one of the battery module housing assemblies to the exhaust manifold, and the method further includes delivering both the exhaust byproducts and the liquid coolant to the exhaust manifold through one of the exhaust branches.

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