Traction battery pack coolant reservoir and coolant management method

Abstract

The invention provides a traction battery pack coolant reservoir and a coolant management method. A traction battery pack assembly includes a coolant reservoir that receives coolant from a traction battery pack. The coolant reservoir is configured to receive the coolant in a direction that causes the coolant to swirl within the coolant reservoir.

Description

Technical Field

[0001] The present disclosure generally relates to managing heat and exhaust byproducts within a traction battery pack. Background Art

[0002] An electrified vehicle differs from a conventional motor vehicle in that an electrified vehicle includes a drive train having one or more electric machines. The electric machines may drive the electrified vehicle as an alternative to or in addition to an internal combustion engine. A traction battery pack assembly may power the electric machines. A coolant may be moved through the traction battery pack to help manage heat within the traction battery pack. Summary of the invention

[0003] In some aspects, the technology described herein relates to a traction battery pack assembly including a coolant reservoir that receives coolant from a traction battery pack, the coolant reservoir being configured to receive the coolant in a direction that causes the coolant to swirl within the coolant reservoir.

[0004] In some aspects, the technology described herein relates to a traction battery pack assembly in which the coolant reservoir is cylindrical.

[0005] In some aspects, the technology described herein relates to a traction battery pack assembly wherein a side wall of the coolant reservoir includes an inlet of the coolant reservoir, wherein a vertical bottom of the coolant reservoir includes an outlet of the coolant reservoir.

[0006] In some aspects, the technology described herein relates to a traction battery pack assembly that also includes a vent for the coolant reservoir.

[0007] In some aspects, the technology described herein relates to a traction battery pack assembly wherein a side wall of the coolant reservoir includes an inlet of the coolant reservoir, wherein a vertical bottom of the coolant reservoir includes an outlet of the coolant reservoir, and wherein the exhaust port is located at a vertical top of the coolant reservoir.

[0008] In some aspects, the technology described herein relates to a traction battery pack assembly wherein the coolant is a liquid coolant.

[0009] In some aspects, the technology described herein relates to a traction battery pack assembly, which also includes: a mesh barrier disposed within an interior of the coolant reservoir, an inlet of the coolant reservoir disposed on a first side of the mesh barrier, and an exhaust port disposed on an opposite second side of the mesh barrier.

[0010] In some aspects, the technology described herein relates to a traction battery pack assembly wherein the coolant reservoir is configured to cause vortexing of the coolant.

[0011] In some aspects, the technology described herein relates to a traction battery pack assembly wherein the coolant reservoir is configured to cause the coolant to swirl about a longitudinal axis of the coolant reservoir.

[0012] In some aspects, the technology described herein relates to a traction battery pack assembly wherein the interior of the coolant reservoir includes a volume of air.

[0013] In some aspects, the technology described herein relates to a traction battery pack assembly in which the coolant reservoir is part of a flooded thermal management system.

[0014] In some aspects, the technology described herein relates to a traction battery pack assembly that also includes a traction battery pack and a conduit configured to convey coolant from the traction battery pack to a coolant reservoir.

[0015] In some aspects, the technology described herein relates to a traction battery pack assembly wherein the coolant reservoir is a vapor-liquid separator.

[0016] In some aspects, the technology described herein relates to a method of managing coolant, the method comprising: receiving coolant from a traction battery pack at a coolant reservoir; separating air from the coolant within the coolant reservoir; and exhausting the air from the coolant reservoir.

[0017] In some aspects, the technology described herein relates to a method that also includes swirling the coolant within the coolant reservoir.

[0018] In some aspects, the technology described herein relates to a method that also includes receiving the coolant from an inlet in a side wall of the coolant reservoir and conveying the coolant from the coolant reservoir through an outlet at a raised bottom of the coolant reservoir.

[0019] In some aspects, the technology described herein relates to a method wherein the coolant reservoir is configured to cause the coolant to swirl about a longitudinal axis of the coolant reservoir.

[0020] In some aspects, the technology described herein relates to a method that also includes exhausting the air through an exhaust port at a vertical top of the coolant reservoir.

[0021] In some aspects, the technology described herein relates to a method that also includes passing the air through a mesh barrier within an interior of the coolant reservoir before exhausting the air from the coolant reservoir.

[0022] In some aspects, the technology described herein relates to a method in which the coolant reservoir is part of an immersion thermal management system.

[0023] The embodiments, examples and alternatives of the preceding paragraphs, 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 conjunction with one embodiment apply 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 electrified vehicle with a traction battery pack is shown.

[0026] Figure 2 Shown for management Figure 1 Schematic diagram of the immersed thermal management system for the thermal energy levels within the traction battery pack.

[0027] Figure 3 FIG. 1 shows an exemplary embodiment of the present disclosure. Figure 2 The coolant reservoir of the system.

[0028] Figure 4 Show Figure 3 A cross-sectional view of a coolant reservoir. DETAILED DESCRIPTION

[0029] The present disclosure details an exemplary coolant reservoir for a traction battery pack and an exemplary method of managing coolant for a traction battery pack. The coolant reservoir may be part of an immersion thermal management system. In an immersion thermal management system, components of a traction battery, such as battery cells, may be at least partially immersed in a coolant.

[0030] When the battery cells are immersed in the coolant, exhaust byproducts exhausted from the battery cells may be discharged into the liquid coolant, thereby creating a mixture of coolant and exhaust byproducts. The mixture is transferred back to the coolant reservoir.

[0031] Example coolant reservoirs and coolant management methods may facilitate separation of exhaust byproducts from the mixture so that liquid coolant without gaseous byproducts may be circulated back to the traction battery pack.

[0032] refer to Figure 1 , the electrified vehicle 10 includes a traction battery pack 14, an electric motor 18, and wheels 22. The traction battery pack 14 provides power to the electric motor 18, which can convert the electricity into mechanical power to drive the wheels 22. The traction battery pack 14 can be a relatively high voltage battery.

[0033] In the exemplary embodiment, the traction battery pack 14 is secured to an underbody 26 of the electrified vehicle 10. In other examples, the traction battery pack 14 may be located elsewhere on the electrified vehicle 10.

[0034] 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.

[0035] Reference now Figure 2 , the traction battery pack 14 includes cell stacks 30 held within a housing assembly 34. Each of the cell stacks 30 may include a plurality of individual battery cells.

[0036] A plurality of battery cells (or simply "cells") are used to supply power to various components of the electrified vehicle 10. The battery cells are stacked side by side relative to each other to provide a cell stack 30. In the exemplary embodiment, the housing assembly 34 includes a housing cover and a housing tray. The housing cover is secured to the housing tray to provide an interior area 38 that accommodates the cell stack 30. The traction battery pack 14 includes four cell stacks 30 located within an interior area 44 of the housing assembly 34.

[0037] Although in the present disclosure Figure 2 A specific number of battery cell stacks 30 are shown in the figure, but the traction battery pack 14 may include any number of battery cells and battery cell stacks 30. In other words, the present disclosure is not limited to Figure 2 The specific configuration of the battery cells and battery cell stack 30 is shown in FIG.

[0038] In this example, the battery cells within the cell stack 30 are prismatic lithium-ion pouch cells. However, within the scope of the present disclosure, battery cells having other geometries (cylindrical, etc.) and / or chemistries (nickel-metal hydride, lead acid, etc.) may alternatively be utilized.

[0039] As the vehicle 10 operates, thermal energy levels within the battery cells and the cell stack 30 may increase. The example vehicle 10 incorporates a thermal management system to manage thermal energy levels within the battery cells, the cell stack 30, and other areas of the traction battery pack 14. The thermal management system may be used to cool the battery cells of the cell stack 30. In some examples, the thermal management system may be used to heat the battery cells of the cell stack 30.

[0040] The example thermal management system includes a coolant loop 40 extending from a coolant reservoir 46, through a heat exchange device 50, through a pump 54, through the traction battery pack 14, and then back to the coolant reservoir 46. The coolant loop 40 may include conduits that fluidly couple the traction battery pack 14, the coolant reservoir 46, the heat exchange device 50, and the pump 54 together.

[0041] The pump 54 may be operated to circulate the coolant along the coolant loop 40 . In this example, the coolant fills the housing assembly 34 of the traction battery pack 14 to immerse the components of the traction battery pack 14 (e.g., the cell stack 30 ) within the coolant. Thus, a portion of the coolant loop 40 is provided by the traction battery pack 14 .

[0042] An example thermal management system is an immersion system. A coolant may absorb thermal energy from components immersed in the coolant to cool those components. In this example, the coolant is a dielectric fluid. The coolant may be oil.

[0043] The coolant flows along the coolant loop 40 from the traction battery pack 14 to the coolant reservoir 46. From the coolant reservoir 46, the coolant flows along the coolant loop 40 to the thermal energy exchange device 50. Thermal energy may be transferred from the coolant at the thermal energy exchange device 50, which may be a liquid-to-liquid heat exchanger or a liquid-to-air heat exchanger.

[0044] Coolant may be moved from the heat exchange device 50 back to the traction battery pack 14 by the pump 54 to absorb more thermal energy from the components of the traction battery pack 14 .

[0045] In addition to managing thermal energy, example thermal management systems may also help manage exhaust byproducts.

[0046] For example, from time to time, one or more of the battery cells within the traction battery pack 14 may experience a thermal event, which may result in battery cell venting. The thermal event may be caused by an overcharge condition, an overdischarge condition, or other conditions.

[0047] When venting, the battery cell vents exhaust byproducts V, which may include gases, effluent particles, and / or other exhaust byproducts. The battery cell may include a diaphragm that ruptures in response to an increase in pressure within the battery cell. The exhaust byproducts are exhausted through the ruptured exhaust port.

[0048] Within the traction battery pack 14, the battery cells are immersed in a coolant. Therefore, if one or more of the battery cells exhaust gases, the exhaust byproducts V are exhausted into the coolant. An example thermal management system, and in particular a coolant reservoir, helps manage these exhaust byproducts V.

[0049] refer to Figure 3 and Figure 4 And continue to refer to Figure 1 and Figure 2 In the exemplary embodiment, coolant reservoir 46 is cylindrical and includes a vertical bottom 60, a vertical top 64, and sidewalls 68 extending from vertical bottom 60 to vertical top 64. For purposes of this disclosure, vertical is referenced to the ground and the general orientation of vehicle 10 during operation.

[0050] The coolant reservoir 46 includes an interior region 72. The volume of the interior region 72 is capable of containing enough coolant to operate the immersion system without completely filling the interior region. Thus, some of the interior region contains air.

[0051] The coolant reservoir 46 includes an inlet 76 in the side wall 68 and an outlet 80 in the vertical bottom 60. The coolant reservoir 46 additionally includes an exhaust port 84 in the vertical top 64 of the coolant reservoir 46.

[0052] The inlet 76 guides the coolant C into the coolant reservoir 46. The outlet 80 discharges the coolant C from the coolant reservoir.

[0053] Positioning the inlet 76 in the sidewall 68 may cause the coolant reservoir 46 to receive coolant in a direction that causes the coolant C to swirl within the coolant reservoir 46. The inlet 76 is designed to direct the coolant C tangentially to the longitudinal axis A of the coolant reservoir 46 to promote swirl.

[0054] The swirl of the coolant C may result in a vortex F of the coolant within the coolant reservoir 46. The coolant experiencing the vortex F rotates about the longitudinal axis A as it moves downward toward the outlet 80. Positioning the outlet 80 at the longitudinal axis A substantially aligned with the axis about which the vortex rotates may further facilitate the vortex of the coolant C and the discharge of the coolant C from the coolant reservoir 46.

[0055] If one or more exhaust gases in the battery cells cause the coolant to mix with the exhaust byproducts V and in particular with the exhaust gases, the mixture of coolant C and exhaust byproducts V is introduced into the coolant reservoir 46. The vortex of the coolant C and exhaust byproduct V mixture within the coolant reservoir 46 can help separate the exhaust byproducts V from the coolant. The exhaust byproducts V can then move vertically upward to the exhaust port 84, which discharges the exhaust byproducts V from the coolant reservoir 46. The coolant C with the exhaust products V removed can then pass through the outlet 80. The coolant reservoir 46 can be considered a vapor-liquid separator.

[0056] The exhaust port 84 may be an opening in the vertical top 64 of the coolant reservoir 46. The exhaust port 84 may be a one-way exhaust port or a pressure equalization valve. In some examples, the exhaust port 84 is similar in style to a radiator cap.

[0057] The example coolant reservoir 46 includes a mesh barrier 88 disposed within the interior region 72. The mesh barrier 88 is positioned between the inlet 76 and the exhaust port 84. That is, the inlet 76 of the coolant reservoir 46 is disposed on a first side of the mesh barrier 88, and the exhaust port 84 is disposed on an opposing second side of the mesh barrier 88.

[0058] The mesh barrier 88 may be an oleophilic mesh barrier to attract coolant and retain coolant splash within the interior region 72, rather than coolant splash exiting the coolant reservoir 46 through the exhaust port 84. As configured in this example, the exhaust byproducts V must pass through the mesh barrier 88 before exiting the coolant reservoir 46 through the exhaust port 84.

[0059] Features of the disclosed examples include a coolant reservoir that can contain exhaust byproducts exhausted from battery cells of a traction battery pack.

[0060] The foregoing description is illustrative rather than 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.

Claims

1. A traction battery pack assembly, wherein include: A coolant reservoir receives coolant from a traction battery pack, the coolant reservoir being configured to receive the coolant in a direction that causes the coolant to swirl within the coolant reservoir.

2. The traction battery pack assembly of claim 1 , wherein the coolant reservoir is cylindrical, and optionally, wherein a side wall of the coolant reservoir comprises an inlet of the coolant reservoir, and wherein a vertical bottom of the coolant reservoir comprises an outlet of the coolant reservoir.

3. The traction battery pack assembly of claim 1 further comprising a vent for the coolant reservoir, and optionally wherein a side wall of the coolant reservoir comprises an inlet for the coolant reservoir, wherein a vertical bottom of the coolant reservoir comprises an outlet for the coolant reservoir, and wherein the vent is located at a vertical top of the coolant reservoir.

4. The traction battery pack assembly of claim 1, wherein the coolant is a liquid coolant.

5. The traction battery pack assembly according to claim 1, further comprising: include: A mesh barrier is disposed within an interior of the coolant reservoir, an inlet to the coolant reservoir is disposed on a first side of the mesh barrier, and an exhaust port is disposed on an opposing second side of the mesh barrier.

6. The traction battery pack assembly of claim 1 , wherein the coolant reservoir is configured to cause the coolant to swirl about a longitudinal axis of the coolant reservoir, and optionally wherein the coolant reservoir is configured to cause a vortex of the coolant.

7. The traction battery pack assembly of claim 1, wherein the interior of the coolant reservoir includes a volume of air.

8. The traction battery pack assembly of claim 1, wherein the coolant reservoir is part of a flooded thermal management system.

9. The traction battery pack assembly of claim 1 further comprising a traction battery pack and a conduit configured to convey the coolant from the traction battery pack to the coolant reservoir.

10. The traction battery pack assembly of claim 1, wherein the coolant reservoir is a vapor-liquid separator.

11. A method for managing a coolant, wherein include: At a coolant reservoir, receiving coolant from a traction battery pack; In the coolant reservoir, separating air from the coolant; as well as The air is exhausted from the coolant reservoir.

12. The method of claim 11 further comprising swirling the coolant within the coolant reservoir, and optionally wherein the coolant reservoir is configured to cause the coolant to swirl about a longitudinal axis of the coolant reservoir.

13. The method of claim 11 further comprising receiving the coolant from an inlet in a side wall of the coolant reservoir and conveying the coolant from the coolant reservoir through an outlet at an upstanding bottom of the coolant reservoir.

14. The method of claim 11 further comprising exhausting the air through an exhaust port at a vertical top of the coolant reservoir, and optionally further comprising passing the air through a mesh barrier within an interior of the coolant reservoir prior to exhausting the air from the coolant reservoir.

15. The method of claim 11, wherein the coolant reservoir is part of an immersion thermal management system.

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