Thermal interface material mounting within traction battery pack

Abstract

The invention provides thermal interface material mounting within a traction battery pack. A method of assembling components of a traction battery includes dispensing a thermal interface material onto a release sheet. The method applies a thermal interface material to a component of the traction battery pack while the thermal interface material remains on the release sheet. The method then separates the release sheet from the thermal interface material while the thermal interface material remains on the component of the traction battery pack.

Description

Technical Field

[0001] The present disclosure generally relates to a traction battery pack, and more particularly to how a thermal interface material (TIM) is installed within a traction battery pack. Background Art

[0002] Electrified vehicles differ from conventional motor vehicles in that they can be selectively driven by one or more electric motors powered by a traction battery pack. Electric motors can propel an electrified vehicle in place of, or in combination with, an internal combustion engine. Thermal interface materials can be used in various areas of the traction battery pack to facilitate thermal management. Summary of the Invention

[0003] In some aspects, the technology described herein relates to a method of assembling components of a traction battery pack, the method comprising: dispensing a thermal interface material onto a release sheet; applying the thermal interface material to a component of the traction battery pack while the thermal interface material remains on the release sheet; and separating the release sheet from the thermal interface material while the thermal interface material remains on the component of the traction battery pack.

[0004] In some aspects, the technology described herein relates to a method wherein the component is a heat exchange plate.

[0005] In some aspects, the technology described herein relates to a method that further includes, after the separation, sandwiching a thermal interface material between the heat exchange plate and the battery array.

[0006] In some aspects, the technology described herein relates to a method that also includes passing a liquid coolant through coolant channels of a heat exchange plate.

[0007] In some aspects, the technology described herein relates to a method that also includes supporting at least one battery array on the component after separating.

[0008] In some aspects, the technology described herein relates to a method that also includes compressing the thermal interface material against the component during applying the thermal interface material to the component.

[0009] In some aspects, the technology described herein relates to a method that also includes dispensing the thermal interface material as a bead.

[0010] In some aspects, the technology described herein relates to a method in which the thermal interface material is silicone-based.

[0011] In some aspects, the technology described herein relates to a method that further includes heating the release sheet to heat the thermal interface material after dispensing.

[0012] In some aspects, the technology described herein relates to a method that further includes, after dispensing, using a conveyor assembly to transport the thermal interface material on the release sheet closer to the component.

[0013] In some aspects, the technology described herein relates to a method that also includes gripping a peripheral edge of a release sheet with a conveyor assembly.

[0014] In some aspects, the technology described herein relates to a method that also includes applying a thermal interface material by operating a conveyor assembly.

[0015] In some aspects, the technology described herein relates to a method in which the release sheet is a first release sheet, and the method further comprises dispensing a bead of thermal interface material on the first release sheet and a second release sheet.

[0016] In some aspects, the technology described herein relates to a method wherein the first peel sheet and the second peel sheet are conveyor slats.

[0017] In some aspects, the technology described herein relates to a traction battery assembly comprising: a release sheet; and a thermal interface material deposited on the release sheet, the release sheet configured to separate from the thermal interface material after the thermal interface material is applied to a traction battery component.

[0018] In some aspects, the technology described herein relates to a traction battery assembly in which the traction battery component is a heat exchange plate.

[0019] In some aspects, the technology described herein relates to a traction battery assembly in which the release sheet is a heated release sheet configured to heat a thermal interface material deposited on the heated release sheet.

[0020] In some aspects, the technology described herein relates to a traction battery assembly that also includes a conveyor assembly that holds a release sheet and is configured to move the release sheet and thermal interface material closer to the component.

[0021] In some aspects, the technology described herein relates to a traction battery assembly wherein the release sheet is a first release sheet, and wherein the thermal interface material is a bead of thermal interface material deposited on the first release sheet and a second release sheet.

[0022] In some aspects, the technology described herein relates to a traction battery assembly wherein the stripper sheet is a conveyor slat.

[0023] The embodiments, examples and alternatives of the preceding paragraphs, claims or following description and drawings, including any of their various aspects or corresponding 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, the various features and advantages of the disclosed examples will become apparent to those skilled in the art. The drawings accompanying the detailed description can be briefly described as follows:

[0025] Figure 1 A side view of an electrified vehicle according to an exemplary aspect of the present disclosure is shown.

[0026] Figure 2 Shown from Figure 1 Expanded view of the battery pack for an electric vehicle.

[0027] Figure 3 Shown is thermal interface material dispensed on a release sheet.

[0028] Figure 4 Shows the applied Figure 2 Thermal interface materials for battery pack components.

[0029] Figure 5 Shows the applied Figure 2 Thermal interface material behind the components of the battery pack.

[0030] Figure 6 Shown is a release sheet removed from the thermal interface material.

[0031] Figure 7 A system for applying thermal interface material to a release sheet and then to the component according to another exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0032] Traction battery packs may include thermal interface materials (TIMs) in a number of areas. For example, a TIM may be applied between two components of the traction battery pack to facilitate thermal energy exchange between the two components.

[0033] refer to Figure 1 In an exemplary, non-limiting embodiment, the electrified vehicle 10 includes a traction battery pack 14 that powers an electric motor 18. The electrified vehicle 10 also includes wheels 22 driven by the electric motor 18. The battery pack 14 can power the electric motor 18, which converts electricity into torque to drive the wheels 22.

[0034] In the exemplary embodiment, the battery pack 14 is secured to the underbody 26 of the electrified vehicle 10. In other examples, the battery pack 14 may be located elsewhere on the electrified vehicle 10. The battery pack 14 may be secured to the underbody 26 using, for example, straps and mechanical fasteners.

[0035] The electrified vehicle 10 is a pure electric vehicle. In other examples, the electrified vehicle 10 is a hybrid electric vehicle that can selectively use torque provided by an internal combustion engine (as an alternative to or in addition to the electric motor) to drive the wheels. In general, the electrified vehicle 10 can be any type of vehicle having a traction battery pack.

[0036] Now refer to Figure 2 The battery pack 14 includes a housing 30 that encloses a plurality of battery arrays 34, each battery array having an associated heat exchange plate 38. In other examples, a single heat exchange plate 38 is associated with more than one battery array 34. The battery array 34 includes, among other things, a plurality of battery cells.

[0037] To manage the thermal energy levels in the battery array 34 and other areas of the traction battery pack 14, a coolant may be circulated between a coolant supply and coolant channels within the heat exchange plates 38. The coolant may be a liquid coolant. Heat exchange plates 38, often referred to as "cold plates," may be used to dissipate the thermal energy. The heat exchange plates 38 each include a conduit 40 that provides an inlet for the coolant to enter the heat exchange plate 38 and an outlet for the coolant to exit the heat exchange plate 38. Other conduits carry coolant back and forth between the conduits and the coolant supply. These conduits are located in the Figure 2 is omitted.

[0038] In this example, thermal interface material (TIM) 42 may be used to facilitate thermal conductivity between the battery arrays 34 and the corresponding heat exchange plates 38. In the past, during assembly of the battery pack 14, beads of TIM 42 were typically dispensed from a TIM dispenser directly onto the heat exchange plates 38 in a desired pattern, which impacted cycle time.

[0039] refer to Figure 3 In an exemplary process of the present disclosure, a TIM 42 is dispensed from a TIM dispenser 46 onto a release sheet 50. The TIM 42 is dispensed as a bead of TIM 42. The TIM 42 is dispensed in a desired pattern, here a serpentine pattern. An actuator 54 (such as a three-axis linear actuator) can be used to move the TIM dispenser 46 relative to the release sheet 50 to dispense the TIM 42 in the desired pattern. The TIM 42 can be silicone-based.

[0040] Next, if Figure 4 As shown, the peeling sheet 50 and the TIM 42 are moved closer together. Figure 2The peel sheet 50 with the TIM 42 in the form of a bead is rotated so that the TIM 42 can be applied directly to the heat exchange plate 38. When the TIM 42 is initially applied to the heat exchange plate 38, the bead of TIM 42 is sandwiched between the peel sheet 50 and the heat exchange plate 38. The peel sheet 50 with the TIM 42 is flipped over to move to the Figure 4 location.

[0041] In some examples, the TIM 42 and release sheet 50 may be compressed into the heat exchange plate 38 when the TIM 42 is applied to the heat exchange plate 38. Movement of the TIM 42 and release sheet 50 toward the components of the battery pack 14 may be automated using a vacuum assist and release mechanism.

[0042] like Figure 5 As shown, when the TIM 42 is initially applied to the heat exchange plate 38 , a bead of the TIM 42 is sandwiched between the release sheet 50 and the heat exchange plate 38 .

[0043] Next, refer to Figure 6 , and then peel sheet 50 is peeled from TIM 42 while TIM 42 remains applied to heat exchange plate 38. TIM 42, peel sheet 50, and heat exchange plate 38 may be designed such that the bond between TIM 42 and heat exchange plate 38 is stronger than the bond between TIM 42 and peel sheet 50. This may facilitate retaining TIM 42 on heat exchange plate 38 when peel sheet 50 is removed.

[0044] like Figure 2 As shown, one of the battery arrays 34 is then positioned atop the heat exchange plate 38 and the TIM 42, such that the TIM 42 is sandwiched between the heat exchange plate 38 and the battery array 34. The TIM 42 is compressed by the battery array 34 into a thin layer of TIM 42. The battery array 34 is then supported on the heat exchange plate 38 with the TIM 42 sandwiched therebetween. The TIM 42 facilitates heat transfer between the battery array 34 and the heat exchange plate 38.

[0045] In some examples, release sheet 50 is polytetrafluoroethylene (PTFE) or a similar type of material.

[0046] In some examples, the release sheet 50 is a heated release sheet that includes heat embedded or stamped wires. Heating the release sheet 50 heats the TIM 42, which in some examples can ensure that the thermal energy level in the TIM 42 is at a level suitable for application to the heat exchange plate 38.

[0047] Dispensing the TIM 42 onto the release sheet 50 and subsequently transferring it to the heat exchange plate 38 can shorten the manufacturing process because waiting to dispense the TIM 42 onto the heat exchange plate 38 does not increase the overall cycle time. Multiple beads of the TIM 42 can be dispensed onto respective release sheets 50 and applied to the heat exchange plate 38 in stages. If desired, multiple beads of the TIM 42 can be dispensed simultaneously so that the dispensing time of the TIM 42 does not substantially affect the overall cycle time.

[0048] In other examples, another method of transporting the TIM 42 and peel sheet 50 to the location of the component (here, the heat exchange plate 38) may be utilized. Figure 7 In the example shown, a stripper sheet 50A is incorporated into the conveyor assembly 58. The stripper sheet 50A may be a conveyor slat. The stripper sheet 50A may alternatively or additionally rest on the conveyor assembly 58. The outer edges of the stripper sheet 50A may be gripped by the conveyor assembly 58. The TIM 42 intended to be applied to a single component of the traction battery pack 14 may span more than one slat or stripper sheet 50A. When the conveyor assembly 58 is operated, the stripper sheet 50A with the applied TIM 42 moves in the direction D1.

[0049] In conjunction with the conveyor assembly 58, the heat exchange plates 38 can be moved in a direction D2 near the end of the conveyor assembly 58. The heat exchange plates 38 can be moved by the conveyor. As the peel sheet 50A with the TIM 42 rotates around the end of the conveyor assembly 58, the TIM 42 is compressed into one of the heat exchange plates 38. Continued rotation of the conveyor assembly 58 and movement of the heat exchange plates 38 in the direction D2 separates the peel sheet 50A from the TIM 42, thereby applying the TIM 42 to the heat exchange plates 38.

[0050] The peel sheet 50A, from which the TIM 42 has been removed, may then be rotated by the conveyor assembly 58 back to a position adjacent the TIM dispenser, where another bead of TIM 42 may be applied to the peel sheet 50A.

[0051] This automated process may further reduce the overall assembly cycle time by automating the transfer of the TIM 42 from the peel sheet 50A to the heat exchange plate 38 .

[0052] Features of the disclosed examples include a process for positioning the TIM within the battery pack, wherein the TIM is dispensed on a peel sheet and then moved to a location where the TIM is bonded to the desired component. Dispensing on a peel sheet can reduce overall cycle time.

[0053] The foregoing description is illustrative rather than restrictive in nature. 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 present disclosure. Therefore, the scope of protection afforded to the present disclosure should be determined solely by studying the appended claims.

Claims

1. A method of assembling components of a traction battery, comprising: dispensing thermal interface material onto a release sheet; applying the thermal interface material to a component of a traction battery pack while the thermal interface material remains on the release sheet; as well as While the thermal interface material remains on the component of the traction battery pack, the release sheet is separated from the thermal interface material.

2. The method of claim 1, wherein the component is a heat exchange plate.

3. The method of claim 2 further comprising, after said separating, sandwiching said thermal interface material between said heat exchange plate and said battery array, and optionally, further comprising passing a liquid coolant through coolant channels of said heat exchange plate.

4. The method of claim 1 further comprising supporting at least one traction battery array on said component after said separating. 5 . The method of claim 1 , further comprising compressing the thermal interface material against the component during said applying the thermal interface material to the component.

6. The method of claim 1 further comprising dispensing the thermal interface material as a bead, and optionally wherein the thermal interface material is silicone-based.

7. The method of claim 1 further comprising, after said dispensing, heating said release sheet to heat said thermal interface material.

8. The method of claim 1 further comprising, after said dispensing, using a conveyor assembly to convey said thermal interface material on said release sheet closer to said component, and optionally, said method comprising clamping a peripheral edge of said release sheet with said conveyor assembly.

9. The method of claim 8, further comprising applying the thermal interface material by operating the conveyor assembly.

10. The method of claim 1 , wherein the release sheet is a first release sheet, and the method further comprises dispensing a bead of the thermal interface material onto the first and second release sheets, and optionally, wherein the first and second release sheets are conveyor slats.

11. A traction battery assembly comprising: peeling sheet; as well as A thermal interface material is deposited on the release sheet, the release sheet being configured to be separated from the thermal interface material after the thermal interface material is applied to a traction battery component.

12. The traction battery assembly of claim 11, wherein the traction battery component is a heat exchange plate. 13 . The traction battery assembly of claim 11 , wherein the release sheet is a heated release sheet configured to heat the thermal interface material deposited thereon.

14. The traction battery assembly of claim 11 , further comprising a conveyor assembly gripping the release sheet, the conveyor assembly configured to move the release sheet and the thermal interface material closer to the component, and optionally wherein the release sheet is a conveyor slat.

15. The traction battery assembly of claim 11, wherein the release sheet is a first release sheet, and wherein the thermal interface material is a bead of thermal interface material deposited on the first and second release sheets.

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