CN116805748A - Gasket system for traction battery pack - Google Patents

Abstract

The present disclosure provides a "gasket system for traction battery packs". Traction battery packs including a battery system are disclosed. The cell stack/cell matrix of the battery system may be positioned within a housing tray of the traction battery pack. The wedge-shaped inserts may be positioned at the interface between the cell stack/cell matrix and the side walls of the housing tray. The sidewalls may include draft angles. The wedge-shaped inserts may be configured to flatten draft angles to apply compressive loads in a direction substantially normal to the cell stack/cell matrix.

Description

Gasket system for traction battery pack

Cross Reference to Related Applications

This disclosure claims priority from U.S. provisional application No. 63/322,766, filed on day 23 of 3.2022, which is incorporated herein by reference.

Technical Field

The present disclosure relates generally to traction battery packs and, more particularly, to a gasket system adapted to provide shimming and wedging functions within a traction battery pack including a battery system, such as a cell-to-cell pack battery system.

Background

An electrically powered vehicle includes a powertrain having one or more electric machines. Alternatively or in addition to the internal combustion engine, the electric machine may drive an electrically powered vehicle. The traction battery pack may power the motor and other electrical loads of the vehicle.

Conventional traction battery packs include a battery cell stack called a battery array. The battery array includes various array support structures (e.g., array frames, spacers, stringers, walls, end plates, ties, etc.) arranged to group and support battery cells in a plurality of individual cells within a traction battery pack housing.

Disclosure of Invention

Traction battery packs according to exemplary aspects of the present disclosure include, among other things: a housing assembly including a housing tray; a battery system housed within the housing assembly and including a matrix of cells; and a wedge insert that establishes an interface between the draft angle of the side wall of the housing tray and the cell matrix.

In another non-limiting embodiment of the aforementioned traction battery pack, the wedge inserts are secured to the secondary sides of the cell matrix.

In another non-limiting embodiment of any of the foregoing traction battery packs, the wedge insert is secured to the cell stack of the cell matrix.

In another non-limiting embodiment of any of the foregoing traction battery packs, the housing tray provides a cell compression opening for compressing the cell matrix.

In another non-limiting embodiment of any of the foregoing traction battery packs, the side walls of the housing tray establish a portion of the cell compression opening.

In another non-limiting embodiment of any of the foregoing traction battery packs, the wedge insert includes a first side that interfaces with the draft angle of the sidewall and a second side that interfaces with the cell matrix.

In another non-limiting embodiment of any of the foregoing traction battery packs, the first side includes a first profile and the second side includes a different second profile.

In another non-limiting embodiment of any of the foregoing traction battery packs, the first profile is slanted or angled and the second profile is flat.

In another non-limiting embodiment of any of the foregoing traction battery packs, an adhesive is disposed between the first side and the sidewall and further between the second side and the cell matrix.

In another non-limiting embodiment of any of the foregoing traction battery packs, the first side includes a first angled surface and a second angled surface that converge together at a top end of the first side.

In another non-limiting embodiment of any of the foregoing traction battery packs, the wedge insert includes a stepped profile.

In another non-limiting embodiment of any of the foregoing traction battery packs, the stepped profile establishes a lip that is received over the top of a portion of the cell matrix.

A method according to another exemplary aspect of the present disclosure comprises, inter alia: the wedge insert is positioned between a sidewall that establishes a draft angle of a housing tray of the traction battery pack and a cell matrix of a battery system of the traction battery pack.

In another non-limiting embodiment of the foregoing method, the wedge insert is positioned between the draft angle and the cell stack of the cell matrix.

In another non-limiting embodiment of any of the foregoing methods, the wedge-shaped inserts are part of a gasket system comprising a plurality of wedge-shaped inserts positioned between the sidewalls and the cell matrix.

In another non-limiting embodiment of any of the foregoing methods, the wedge insert is secured to both the sidewall and the cell matrix by an adhesive.

In another non-limiting embodiment of any of the foregoing methods, the wedge insert includes a first side that interfaces with the draft angle and a second side that interfaces with the cell matrix.

In another non-limiting embodiment of any of the foregoing methods, the first side includes a first angled surface and a second angled surface that meet together at a top end of the first side.

In another non-limiting embodiment of any of the foregoing methods, the first side includes a first profile and the second side includes a different second profile.

In another non-limiting embodiment of any of the foregoing methods, the first profile is slanted or angled and the second profile is flat.

The embodiments, examples and alternatives of the foregoing paragraphs, claims or the following description and drawings (including any of their various aspects or respective individual features) may be employed independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments unless such features are incompatible.

Various features and advantages of this disclosure will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.

Drawings

Fig. 1 schematically shows an electrically powered vehicle.

Fig. 2 shows a traction battery pack of the motorized vehicle of fig. 1.

Fig. 3 illustrates a cell-pack battery system of the traction battery pack of fig. 2.

Fig. 4 shows a spacer system for a traction battery pack having a cell-pack battery system.

Fig. 5 is a cross-sectional view through section 5-5 of fig. 4.

Fig. 6 is a perspective view of a wedge-shaped insert of the shim system of fig. 4.

Fig. 7 is a front view of the wedge insert of fig. 6.

Fig. 8 illustrates another exemplary spacer system for a traction battery pack.

Fig. 9 is an enlarged view of a portion of the structure shown in fig. 5.

Detailed Description

The present disclosure details traction battery packs that include a battery system, such as a cell-pack battery system. The cell stack/cell matrix of the battery system may be positioned within a housing tray of the traction battery pack. The wedge-shaped inserts may be positioned at the interface between the cell stack/cell matrix and the side walls of the housing tray. The sidewalls may include draft angles. The wedge insert may be configured to flatten out (translate) the draft angle to apply a compressive load in a direction substantially normal to the cell stack/cell matrix. These and other features are discussed in more detail in the following paragraphs of this detailed description.

Fig. 1 schematically illustrates an electrically powered vehicle 10. The motorized vehicle 10 may include any type of motorized driveline. In an embodiment, the motorized vehicle 10 is a Battery Electric Vehicle (BEV). However, the concepts described herein are not limited to BEVs and are extendable to other motorized vehicles, including, but not limited to, hybrid Electric Vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles, and the like. Thus, although not specifically shown in the exemplary embodiment, the motorized vehicle 10 may be equipped with an internal combustion engine that may be employed alone or in combination with other power sources to propel the motorized vehicle 10.

In an embodiment, the motorized vehicle 10 is an automobile. However, motorized vehicle 10 may alternatively be a pick-up truck, van, sport Utility Vehicle (SUV), or any other vehicle configuration. Although specific component relationships are shown in the drawings of the present disclosure, the illustrations are not intended to limit the disclosure. The layout and orientation of the various components of the motorized vehicle 10 are schematically illustrated and may vary within the scope of the present disclosure. Furthermore, the various figures attached to this disclosure are not necessarily drawn to scale, and some features may be exaggerated or minimized to emphasize certain details of particular components or systems.

In the illustrated embodiment, the motorized vehicle 10 is a pure electric vehicle propelled solely by electric power (such as by one or more electric machines 12) without the assistance of an internal combustion engine. The electric machine 12 may act as an electric motor, a generator, or both. The electric machine 12 receives electrical power and may convert the electrical power into torque for driving one or more drive wheels 14 of the motorized vehicle 10.

The voltage bus 16 may electrically couple the motor 12 to a traction battery pack 18. Traction battery pack 18 is capable of outputting electrical power to power motor 12 and/or other electrical loads of electric vehicle 10.

The traction battery pack 18 may be secured to an underbody 22 of the motorized vehicle 10. However, it is within the scope of the present disclosure that traction battery pack 18 may be located elsewhere on electric vehicle 10.

Traction battery pack 18 is an exemplary motorized vehicle battery. Traction battery pack 18 may be a high voltage traction battery pack including a cell-pack battery system 20. Unlike conventional traction battery pack battery systems, the battery cell-battery pack battery system 20 incorporates battery cells or other energy storage devices without arranging the cells in separate arrays or modules. Thus, the cell-to-cell battery system 20 eliminates most, if not all, of the array support structures (e.g., array frames, spacers, stringers, walls, end plates, ties, etc.) necessary to group battery cells into arrays/modules. Furthermore, unlike conventional battery systems that require multiple individual battery arrays/modules that must be connected together after being positioned within the battery housing to achieve an overall voltage potential, the cell-to-battery pack battery system 20 can provide the overall voltage bus potential of the traction battery pack 18 with a single battery cell.

Referring now to fig. 2 and 3, the traction battery pack 18 may include a housing assembly 24 arranged to house the battery cell-pack battery system 20. In an embodiment, the battery cell-to-battery pack battery system 20 includes a plurality of battery cells 26 that are held within an interior region 28 established by the housing assembly 24.

The battery cells 26 may supply electrical power to various components of the motorized vehicle 10. The battery cells 26 may be stacked side-by-side with respect to one another to construct a cell stack 30, and the cell stacks 30 may be positioned side-by-side in rows to provide a cell matrix 32.

In an embodiment, each cell stack 30 includes eight individual battery cells 26, and the cell matrix 32 includes four cell stacks 30 for a total of thirty-two battery cells 26. Providing a uniform number of battery cells 26 and a uniform number of cell stacks 30 may help support an efficient electrical bus arrangement. Although a particular number of battery cells 26 and cell stacks 30 are shown in the various figures of the present disclosure, the cell-to-cell pack battery system 20 of the traction battery pack 18 may include any number of battery cells 26 and any number of cell stacks 30. In other words, the present disclosure is not limited to the exemplary configurations shown in fig. 2 and 3.

In an embodiment, battery cell 26 is a prismatic lithium ion cell. However, battery cells having other geometries (cylindrical, soft pack, etc.) and/or chemistries (nickel-metal hydride, lead acid, etc.) may alternatively be utilized within the scope of the present disclosure.

The housing assembly 24 of the traction battery pack 18 may include a housing cover 34 and a housing tray 36. The housing cover 34 may be secured to the housing tray 36 to provide an interior region 28 for housing the battery cell-pack battery system 20.

The housing tray 36 may include a bottom plate 38 and a plurality of side walls 40 arranged relative to one another to provide a cell compression opening 42. The bottom panel 38 and the side walls 40 may be mechanically coupled to each other, such as by welding, for example.

During assembly of traction battery pack 18, housing cover 34 may be secured to housing tray 36 at interface 44 that substantially encloses interior region 28. In some embodiments, mechanical fasteners 46 may be used to secure the housing cover 34 to the housing tray 36, but other fastening methods (adhesion, etc.) may also be suitable.

The cell matrix 32 of the cell-pack battery system 20 may be positioned within the cell compression openings 42 provided by the housing tray 36. The exemplary housing tray 36 is depicted as including a single cell compression opening 42, however, it should be understood that the present disclosure extends to structural assemblies that provide one or more cell compression openings. The housing cover 34 may cover the cell matrix 32 within the cell compression openings 42 to surround the battery cells 26 on substantially all sides. Once fully assembled and positioned relative to the housing tray 36, the cell matrix 32 can establish a single cell that can provide the overall voltage bus potential of the traction battery pack 18.

The housing tray 36 may compress and retain the cell matrix 32 when the cell matrix 32 is received within the cell compression opening 42. In an embodiment, the side walls 40 of the housing tray 36 apply a force to the cell matrix 32 when the cell matrix 32 is positioned within the cell compression openings 42.

In an embodiment, to insert the cell matrix 32 into the cell compression opening 42, the cell matrix 32 may be compressed first and then moved into place in the cell compression opening 42 when compressed. A compressive force F may be applied to opposite ends of one of the cell stacks 30 _C . Compression force F _C The battery cells 26 within the cell stack 30 are substantially compressed, compressing the cell stack 30 and the individual battery cells 26 to a reduced thickness. When the compression force F _C When applied to the cell stack 30, the cell stack 30 may be moved by a downward force F _D Inserted into the corresponding cell compression openings 42. Downward force F _D May be applied directly to one or more of the battery cells 26.

Although the term "downward" is used herein to describe a downward force F _D It should be understood that the term "downward" is also used herein to refer to all forces tending to press the cell stack 30 into the cell compression opening 42. In particular, the term "downward" refers to being substantially perpendicular to the compressive force F _C Whether or not the force is truly in a "downward" direction. For example, the present disclosure extends to compressing and inserting cells laterally into compressed openingsAnd (5) a cell stack.

The cell stack 30 may be individually compressed and inserted into the cell compression opening 42. In another embodiment, the entire cell matrix 32 is compressed and inserted into the cell compression openings 42. As schematically shown in fig. 3, in such an embodiment, an additional compressive force F _X The cell stacks 30 may be compressed together to insert the cell matrix 32 into the cell compression openings 42. Compression force F _X Generally perpendicular to the compressive force F _C . Compression force F _X Can be matched with the compression force F _C Applied together. Force F can then be applied _D To move the entire cell matrix 32 into the cell compression openings 42.

In an embodiment, the entire perimeter of the cell compression opening 42 is defined by the side walls 40 of the housing tray 36. The sidewalls 40 may apply compressive force to the battery cells 26 around the entire perimeter of the cell matrix 32. Thus, the sidewalls 40 may serve as a rigid ring-like structure that compresses and tightly holds the cell matrix 32.

The above-described configuration may be considered a cell-to-cell pack type of battery pack, which is different from conventional battery pack types that include a housing that holds an array of battery cells enclosed by an array support structure spaced apart from the walls of the battery housing, and wherein the battery housing does not apply a compressive force to any battery cells. The cell-pack type battery packs described herein also eliminate the rigid cross members that are typically secured to the housing tray of a conventional traction battery pack to provide mounting points for securing the battery array and housing cover.

The cell-to-battery pack battery system 20 may also include one or more cell row separators 48. In an embodiment, one cell row separator 48 is positioned between each pair of adjacent cell stacks 30 of the cell matrix 32. In other embodiments, two cell row dividers 48 are provided for each cell stack 30. However, the total number of cell row separators 48 disposed within the cell-to-cell battery system 20 is not intended to limit the present disclosure.

With continued reference to fig. 1-3, fig. 4, 5, 6 and 7 illustrate various gasket systems 50 associated with a gasket system 50 that may be utilized within a traction battery pack 18 having a battery cell-pack battery system 20In one aspect. One or more of the side walls 40 of the housing tray 36 may include a draft angle α (see fig. 5) and thus may not exhibit a profile that neatly accommodates all of the battery cells 26 of the cell matrix 32. Furthermore, tolerance variations may be caused by inter-piece dimensional variations between battery cells 26, which may result in some cell stacks 30 of the cell matrix 32 being different in length from other cell stacks 30. Thus, the gasket system 50 may be incorporated into the cell-to-cell pack battery system 20 for controlling the compressive force applied to the cell matrix 32 (e.g., compressive force F _X And/or compressive force F _C ) And is used to fill the gaps caused by tolerance variations within the cell stack 30 of the cell matrix 32.

The shim system 50 may include one or more wedge inserts 52. The wedge-shaped inserts 52 may be positioned relative to the cell matrix 32 before or after inserting the cell matrix 32 into the cell compression openings 42 of the housing tray 36. Further, the wedge inserts 52 may be secured (e.g., via an adhesive or mechanical feature) to the cell matrix 32, the housing tray 36, or both.

In an embodiment, one or more wedge inserts 52 may be positioned between the housing tray 36 and at least two sides (e.g., the minor side 54) of the cell matrix 32. Thus, the wedge-shaped inserts 52 of the shim system 50 may interface with at least two cell stacks 30 of the cell matrix 32, with a first portion P1 of the wedge-shaped inserts 52 positioned at a first side of the cell matrix 32 and a second portion P2 of the wedge-shaped inserts 52 positioned at a second, opposite side of the cell matrix 32. In other embodiments, the wedge-shaped inserts 52 of the shim system 50 may be positioned with respect to only a single side of the cell matrix 32, and thus the shim system 50 may be arranged to interface with only one cell stack 30 of the cell matrix 32 (see, e.g., the embodiment of fig. 8). Accordingly, the total number of wedge-shaped inserts 52 provided as part of the gasket system 50 of the battery cell-pack system 20 may vary and is not intended to limit the present disclosure.

In addition to acting as shims to address tolerance stack-up issues, each wedge insert 52 of the shim system 50 may also establish an interface that flattens or "straightens" the draft angle α of the side wall 40 of the housing tray 36 relative to the cell stack 30/cell matrix 32. Thus, the wedge insert 52 facilitates the transfer of the compressive load 99 applied by the cell compression openings 42 to the cell matrix 32 and may further ensure that the compressive load 99 is applied in a direction substantially normal (i.e., perpendicular) to the cell stack 30/cell matrix 32. The insertion depth D of each wedge insert 52 may be controlled to apply a greater or lesser amount of compressive load to the cell stack 30/cell matrix 32.

The function provided by the wedge-shaped inserts 52 described herein may be particularly beneficial for traction battery packs including battery systems of the cell-pack type, because the array support structure conventionally provided within the battery array has been largely eliminated from the cell-pack battery system 20, and the rigid cross members conventionally provided for establishing mounting points to secure the battery cell packs have been eliminated from the housing tray 36. By means of the wedge-shaped inserts 52, the cell matrix 32 can be inserted directly into the housing tray 36 without the need for ties or other retaining structures.

Referring now primarily to fig. 5, 6 and 7, each wedge-shaped insert 52 of the shim system 50 may include a first side 58 and a second side 60. The first side 58 may include a first profile and the second side 60 may include a second, different profile. The first profile of the first side 58 may be configured to at least partially match the profile of the draft angle α of the side wall 40 of the housing tray 36, and the second profile of the second side 60 may be configured to match the profile of one of the sides of the cell stack 30/cell matrix 32. Thus, in the exemplary embodiment, first side 58 includes a sloped or angled profile and second side 60 includes a substantially flat profile.

In an embodiment, the first side 58 of the wedge-shaped insert 52 includes a first angled surface 62 and a second angled surface 64. The first angled surface 62 and the second angled surface 64 may converge together at a top end 66 of the first side 58. In an embodiment, the second angled surface 64 may be angled to match the profile of the draft angle α of the sidewall 40.

Wedge insert 52 may also include a stepped profile 68. The stepped profile 68 may be disposed adjacent an upper portion of the wedge insert 52 and may thus be connected to the first angled surface 62 of the first side 58. The stepped profile 68 may establish a lip 70. When the wedge insert 52 is positioned between the housing tray 36 and the cell stack 30/cell matrix 32, the lip 70 may extend over the top of a portion of the cell stack 30/cell matrix 32 to help maintain the Z-axis position of the cell matrix 32 within the cell compression opening 42. In other embodiments, the lip 70 may extend away from the cell stack 30/cell matrix 32 and rest against a portion of the housing tray 36. In this manner, the wedge inserts 52 may be pre-placed into the housing tray 36 and held in place at least in part by the lips 70 to prevent the wedge inserts 52 from sliding into the housing tray 36 when the compressed cell stack 30 is inserted into the cell compression opening 42.

Referring to fig. 9, each wedge-shaped insert 52 may be secured in place by an adhesive 72. For example, the adhesive 72 may be applied between the first side 58 of the wedge-shaped insert 52 and the side wall 40 of the housing tray 36, and may be further applied between the second side 60 of the wedge-shaped insert 52 and the side of the cell stack 30/cell matrix 32. Once cured, the adhesive 72 may hold the wedge-shaped inserts 52 in place and increase the stiffness of the cell matrix 32. The adhesive 72 may be a structural adhesive (such as an epoxy) or any other suitable adhesive. In other embodiments, the adhesive 72 may include one or more double-sided tape sections.

Wedge insert 52 may be a polymer-based component. For example, wedge insert 52 may be comprised of a hollow core polymer including structural ribs adapted to resist cell expansion loads applied by the cell cells 26 of cell stack 30/cell matrix 32. The hollow core polymer may alternatively be formed to resist the cell expansion load applied by the cell 26 while allowing some deformation of the hollow core to accommodate cell expansion growth. Exemplary materials include, but are not limited to, thermoset materials (e.g., sheet molding compounds, bulk molding compounds, etc.) or fiber reinforced thermoplastics (e.g., polyamides with glass fiber fillers). In other embodiments, the wedge insert 52 may be formed from a metal component, such as a sheet metal stamping, that is added to the interior and welded to the shell tray structure to straighten any non-flat draft angle.

An example traction battery pack of the present disclosure includes a housing wall incorporating a draft angle, and thus includes features (e.g., wedge inserts) configured to act as both shims to adjust the tolerance stack-up and wedges for controlling the compressive force applied to interface the battery cells. Wedge inserts provide a solution to various assembly complexities that may occur due to the elimination of many array support structures and tray rigid cross members associated with conventional traction battery packs.

Although various non-limiting embodiments are shown with specific components or steps, embodiments of the present disclosure are not limited to these specific combinations. Some features or components from any of the non-limiting embodiments may be used in combination with features or components from any of the other non-limiting embodiments.

It should be understood that the same reference numerals indicate corresponding or analogous elements throughout the several views. It should be understood that while particular component arrangements are disclosed and illustrated in the exemplary embodiments, other arrangements may benefit from the teachings of this disclosure.

The above description should be construed as illustrative and not in any limiting sense. Those of ordinary skill in the art will appreciate that some modifications may occur within the scope of the present disclosure. For these reasons, the following claims should be studied to determine the true scope and content of this disclosure.

Claims (15)

1. A traction battery pack, comprising:

a housing assembly including a housing tray;

a cell-battery pack battery system housed within the housing assembly and including a cell matrix; and

a wedge-shaped insert that establishes an interface between the draft angle of the side wall of the housing tray and the cell matrix.

2. The traction battery pack of claim 1, wherein the wedge insert is secured to a secondary side of the cell matrix, and optionally wherein the wedge insert is secured to a cell stack of the cell matrix.

3. The traction battery pack of claim 1 or 2, wherein the housing tray provides a cell compression opening for compressing the cell matrix, and optionally wherein the side walls of the housing tray establish a portion of the cell compression opening.

4. The traction battery pack of any preceding claim, wherein the wedge insert comprises a first side that interfaces with the draft angle of the sidewall and a second side that interfaces with the cell matrix.

5. The traction battery pack of claim 4, wherein the first side includes a first profile and the second side includes a second, different profile.

6. The traction battery pack of claim 5, wherein the first profile is sloped or angled and the second profile is flat.

7. The traction battery pack of claim 4, comprising an adhesive disposed between the first side and the sidewall and further disposed between the second side and the cell matrix.

8. The traction battery pack of claim 4, wherein the first side includes a first angled surface and a second angled surface that converge together at a top end of the first side.

9. The traction battery pack of any preceding claim, wherein the wedge insert comprises a stepped profile, and optionally wherein the stepped profile establishes a lip that is received over the top of a portion of the cell matrix.

10. A method, comprising:

the wedge-shaped inserts are positioned between the sidewall of the draft angle of the housing tray that establishes the traction battery pack and the cell matrix of the cell-pack battery system of the traction battery pack.

11. The method of claim 10, wherein the wedge insert is positioned between the draft angle and a cell stack of the cell matrix.

12. The method of claim 10 or 11, wherein the wedge-shaped inserts are part of a gasket system comprising a plurality of wedge-shaped inserts positioned between the sidewalls and the cell matrix.

13. The method of any one of claims 10 to 12, wherein the wedge-shaped inserts are secured to both the sidewalls and the cell matrix by an adhesive.

14. The method of any of claims 10 to 13, wherein the wedge insert comprises a first side that interfaces with the draft and a second side that interfaces with the cell matrix, and optionally wherein the first side comprises a first angled surface and a second angled surface that come together at a top end of the first side.

15. The method of claim 14, wherein the first side comprises a first profile and the second side comprises a second, different profile, and optionally wherein the first profile is slanted or angled and the second profile is flat.