CN116805717A - Method for assembling traction battery pack - Google Patents

Abstract

The present disclosure provides a method for assembling a traction battery pack. A manufacturing process for assembling a traction battery pack including a battery system, such as a cell-pack battery system, is disclosed. An exemplary method of assembly includes inserting one or more cell stacks of a cell-battery pack system into a cell compression opening of a housing tray. The method may involve the use of a slide plate that provides a sliding surface that facilitates insertion of the cell stack into the cell compression opening.

Description

Method for assembling 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 methods of assembling traction battery packs including battery systems (such as cell-pack battery systems) using sliding surfaces.

Background

Motorized vehicles differ from conventional motor vehicles in that motorized vehicles include a drive train 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

A method for assembling a traction battery pack according to an exemplary aspect of the present disclosure includes, among other things: disposing a set of battery cells in a compression fixture (fixture); compressing the set of battery cells within a compression fixture between a first sled and a second sled to provide a first cell stack; positioning a first cell stack relative to a housing tray of a traction battery pack; and inserting the first cell stack into the cell compression opening of the housing tray.

In another non-limiting embodiment of the foregoing method, the cell stack is part of a cell-pack battery system that pulls the battery pack.

In another non-limiting embodiment of any of the foregoing methods, the method comprises: after insertion, a compressive force is applied to the cell stack via the cell compression opening.

In another non-limiting embodiment of any of the foregoing methods, disposing the set of battery cells includes stacking the set of battery cells between a first sled and a second sled along a cell stack axis.

In another non-limiting embodiment of any of the foregoing methods, a separator is disposed between each pair of adjacent battery cells in the set of battery cells.

In another non-limiting embodiment of any of the foregoing methods, inserting the cell stack into the cell compression opening comprises applying a downward force to the first cell stack to move the first cell stack into the housing tray.

In another non-limiting embodiment of any of the foregoing methods, compressing the set of battery cells includes applying a compression force along the cell stack axis via a compression clamp to compress the set of battery cells between the first sled and the second sled.

In another non-limiting embodiment of any of the foregoing methods, positioning the first cell stack comprises positioning the first cell stack above a housing tray.

In another non-limiting embodiment of any of the foregoing methods, inserting the first cell stack includes inserting the first cell stack into the housing tray using a top-down method.

In another non-limiting embodiment of any of the foregoing methods, the first slide plate and the second slide plate each include a chamfered leading edge for facilitating insertion.

In another non-limiting embodiment of any of the foregoing methods, the first slide and the second slide each include a sliding surface for facilitating insertion.

In another non-limiting embodiment of any of the foregoing methods, the first slide and the second slide each comprise a frame and a compressible material. The compressible material is configured to allow the set of battery cells to expand within the first cell stack after insertion.

In another non-limiting embodiment of any of the foregoing methods, the method comprises: attaching a first sled to a first battery cell of the set of battery cells with a first adhesive prior to compression; and attaching a second sled to a second battery cell of the set of battery cells with a second adhesive.

In another non-limiting embodiment of any of the foregoing methods, the method includes disposing a second set of battery cells in a second compression fixture; compressing the second set of battery cells within the second compression fixture between the third slide and the fourth slide to provide a second cell stack; positioning a second cell stack relative to the housing tray; and inserting a second cell stack into the cell compression opening of the housing tray at a location adjacent to the first cell stack.

In another non-limiting embodiment of any of the foregoing methods, the method includes inserting the cell stack of the cell-pack battery system into the cell compression opening of the housing tray of the traction battery pack. During insertion, the slide plate of the cell stack provides a sliding surface for facilitating insertion of the cell stack.

In another non-limiting embodiment of any of the foregoing methods, the method comprises: prior to insertion, a compressive force is applied to compress the cell stack to a desired length.

In another non-limiting embodiment of any of the foregoing methods, the compressive force is applied along the cell stack axis by a compression clamp.

In another non-limiting embodiment of any of the foregoing methods, the slide plate is provided with a chamfered leading edge for facilitating insertion.

In another non-limiting embodiment of any of the foregoing methods, the inserting includes applying a downward force to move the cell stack into the housing tray.

In another non-limiting embodiment of any of the foregoing methods, the downward force is applied transverse to a compressive force applied to the cell stack during insertion.

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, 5 and 6 schematically illustrate a method of assembling a traction battery pack comprising a cell-battery pack battery system.

Fig. 7 is an enlarged view of selected portions of fig. 6.

Detailed Description

The present disclosure details a manufacturing process for assembling a traction battery pack including a battery system, such as a cell-pack battery system. An exemplary method of assembly includes inserting one or more cell stacks of a cell-battery pack system into a cell compression opening of a housing tray. The method may involve the use of a slide plate that provides a sliding surface that facilitates insertion of the cell stack into the cell compression opening. 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 within the battery housing. 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. In another embodiment, each cell stack 30 includes ten individual battery cells 26, and the cell matrix 32 includes five cell stacks 30 (see fig. 4) of fifty total 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, 3, and 4.

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 individual battery cells 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 compressive force to the cell matrix 32 when the cell matrix 32 is positioned within the cell compression openings 42. The entire perimeter of the cell compression opening 42 may be established 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 an outer 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 outer housing does not apply a compressive force to any battery cells. The cell-pack type battery packs described herein also eliminate the case tray that is typically secured to a conventional traction battery pack to provide a rigid cross member for securing mounting points for the battery array and case cover as well as structural rigidity.

The cell-to-battery pack battery system 20 may 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.

The battery cell-pack battery system 20 may also include one or more skids 50. A slide plate 50 may be positioned between each cell stack 30 and the housing tray 36, with one slide plate 50 positioned at each longitudinal extent of each cell stack 30. As discussed further below, the slide 50 may facilitate insertion of each cell stack 30 into the cell compression opening 42 of the housing tray 36.

With continued reference to fig. 1-3, fig. 4, 5 and 6 schematically illustrate a method for assembling portions of the traction battery pack 18. The method may include a greater or lesser number of steps than those recited below, and the exact order of the steps is not intended to limit the disclosure.

Referring first to fig. 4, each cell stack 30 of the cell-battery pack system 20 may be first staged by positioning a set of battery cells 26 within a compression fixture 70. The battery cells 26 may be arranged relative to one another along a cell stack axis a. The compression fixture 70 may provide a reference point with respect to at least two adjacent sides (e.g., bottom and ends) of the set of battery cells 26 to arrange the battery cells 26 along the cell stack axis a.

In this embodiment, within the cell stack 30, a spacer plate 52 is disposed between each pair of adjacent battery cells 26 along the stack axis a. The spacer 52 may include a frame portion 54 that holds a compressible material 56. The compressible material 56 may compress to allow some expansion of the battery cells 26. In an embodiment, the compressible material 56 is foam. However, other compressible materials may alternatively be utilized.

Each separator 52 may be secured to two surrounding battery cells 26 by an adhesive 58. In an embodiment, the adhesive 58 is double-sided tape.

Further, a sled 50 may be provided at each opposing axial end of the set of battery cells 26. The skids 50 may each include a frame portion 60 that holds a compressible material 62. The frame portion 60 may be made of a relatively dense material (e.g., a rigid thermoplastic or thermoset polymer such as PA6, PA66, PP, PBT, UP, or any other similar polymer).

The compressible material 62 may compress to allow some expansion of the battery cells 26. In an embodiment, the compressible material 62 is foam. However, other compressible materials may alternatively be utilized.

One sled 50 may be secured to the battery cells 26 at each opposite axial end of the set of battery cells 26 by an adhesive 58. In an embodiment, the adhesive 58 is double-sided tape.

Referring to fig. 5, the sled 50, the battery cells 26, and the spacer plates 52 may then be compressed along the cell stack axis a to provide one of the cell stacks 30. Compression clamp 70 may apply a compressive force F along cell stack axis a to opposite ends of cell stack 30 _C . Compression force F _C The battery cells 26 between the skids 50 are substantially compressed, compressing the cell stack 30 and individual battery cells 26 to the desired stack length.

In an embodiment, the compressive force F exerted by the compression clamp 70 on the battery cells 26 _C Is about 3 kilonewtons. However, the actual compressive force applied may vary depending on the type of battery cell and other factors. In this disclosure, the term "about" means that the expressed amount or range need not be exact, but may be approximate and/or larger or smaller, reflecting acceptable tolerances, conversion factors, measurement errors and the like.

The compression fixture 70 may be driven by a pneumatic actuator to compress the battery cells 26 along the cell stack axis a. However, other types of actuators (such as DC electrical or mechanical screw actuators) may alternatively be employed to achieve compression.

Next, as shown in fig. 6, the cell stack 30 previously arranged and compressed in the manner shown in fig. 4 and 5 may be moved relative to the housing tray 36And (5) positioning. In an embodiment, the cell stack 30 may be positioned vertically above the housing tray 36 with the bottom plate 38 facing upward toward the cell stack. As schematically shown, the compressive force F may be maintained during positioning of the cell stack 30 _C 。

Using a top-down method, it is then possible to apply a downward force F _D The cell stack 30 is inserted into the cell compression opening 42 of the housing tray 36. Thus, the cell stacks 30 may be individually inserted into the housing tray 36. Downward force F _D May be applied directly to one or more of the battery cells 26 of the cell stack 30. Downward force F _D At a substantially right angle to the compressive force F _C Is applied in the direction of (2). Downward force F _D May be provided by another actuator.

Although the term "downward" is used herein to describe a downward force F _D It should be understood, however, that the term "downward" is also used herein to refer to a force 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 cell stacks that are compressed laterally and inserted into cell compression openings.

To facilitate insertion, the slide plate 50 associated with the cell stack 30 may include a chamfered or curved leading edge 64 (see fig. 7). The chamfer on the leading edge 64 may help guide the cell stack 30 into the cell compression opening 42 during insertion. Further, the sliding surface 66 of each sled 50 (e.g., the surface facing away from the battery cells 26) may directly interface with one of the side walls 40 of the housing tray 36 during insertion.

After insertion, the cell compression openings 42 of the housing tray 36 may circumferentially surround the cell stack 30. Thus, the cell compression openings 42 may exert a compressive force on the cell stack 30. The cell compression openings 42 may allow for some expansion of the battery cells 26 after they are removed from the compression fixture 70. The compressive force exerted by the housing tray 36 on the cell stack 30 after insertion may be less than the compressive force F exerted by the compression clamp 70 on the cell stack 30 _c 。

In an exemplary method, the method steps schematically illustrated in fig. 4-6 may be performed four times to provide and insert four cell stacks 30 of the cell-battery pack system 20. Each of the cell stacks 30 is compressed and held by a different compression fixture of the analog compression fixture 70. Thus, in the exemplary embodiment, four compression clamps 70 will be used to provide four cell stacks 30 of the exemplary cell-battery pack system 20.

In the above-described exemplary method, each cell stack 30 is inserted into the case tray 36 using a top-down method. However, a bottom-up approach may alternatively be used to insert the cell stack 30 into the ring structure. Further, although the cell stack 30 is schematically illustrated as being inserted alone, the cell stack 30 may be inserted together into the cell compression opening 42 of the housing tray 36 as a unit of two or more cell stacks (e.g., the cell matrix 32).

The example manufacturing process described herein provides a method for assembling a traction battery pack including a cell-battery pack battery system. As part of the proposed method, the battery cells of a cell-to-battery pack battery system can advantageously be compressed together between skids, providing a solution to various assembly complexities that can arise from eliminating many array support structures 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 method of assembling a traction battery pack, comprising:

disposing a set of battery cells in a compression fixture;

compressing the set of battery cells within the compression fixture between a first sled and a second sled to provide a first cell stack;

positioning the first cell stack relative to a housing tray of the traction battery pack; and

the first cell stack is inserted into a cell compression opening of the housing tray.

2. The method of claim 1, wherein the cell stack is part of a cell-to-cell pack battery system of the traction battery pack.

3. The method of claim 1 or 2, comprising: after the inserting, a compressive force is applied to the cell stack via the cell compression opening.

4. The method of any preceding claim, wherein arranging the set of battery cells comprises:

the set of battery cells is stacked along a cell stack axis between the first sled and the second sled, and optionally wherein a spacer is disposed between each pair of adjacent battery cells in the set of battery cells.

5. The method of any preceding claim, wherein inserting the cell stack into the cell compression opening comprises:

a downward force is applied to the first cell stack to move the first cell stack into the housing tray.

6. The method of any preceding claim, wherein compressing the set of battery cells comprises:

a compression force is applied along a cell stack axis via the compression clamp to compress the set of battery cells between the first slide plate and the second slide plate.

7. The method of any preceding claim, wherein positioning the first cell stack comprises:

positioning the first cell stack above the housing tray, and optionally, wherein inserting the first cell stack comprises inserting the first cell stack into the housing tray using a top-down method.

8. The method of any preceding claim, wherein the first and second slides each comprise a chamfered leading edge or sliding surface for facilitating the insertion.

9. The method of any preceding claim, wherein the first sled and the second sled each comprise a frame and a compressible material configured to allow the set of battery cells to expand within the first cell stack after the inserting.

10. A method as claimed in any preceding claim, the method comprising: attaching the first sled to a first battery cell of the set of battery cells with a first adhesive prior to the compressing; and attaching the second sled to a second battery cell of the set of battery cells with a second adhesive.

11. A method as claimed in any preceding claim, comprising:

disposing a second set of battery cells in a second compression fixture;

compressing the second set of battery cells within the second compression fixture between a third sled and a fourth sled to provide a second cell stack;

positioning the second cell stack relative to the housing tray; and

the second cell stack is inserted into the cell compression opening of the housing tray at a location adjacent to the first cell stack.

12. A method of assembling a traction battery pack, comprising:

inserting a cell stack of a cell-pack battery system into a cell compression opening of a housing tray of the traction battery pack,

wherein the slide plate of the cell stack provides a sliding surface for facilitating insertion of the cell stack during the insertion.

13. The method of claim 12, comprising: prior to the insertion of the insert into the cavity,

a compressive force is applied to compress the cell stack to a desired length, and optionally wherein the compressive force is applied along a cell stack axis by a compression clamp.

14. The method of claim 12 or 13, wherein the sled provides a chamfered leading edge for facilitating the insertion.

15. The method of any one of claims 12 to 15, wherein the inserting comprises:

a downward force is applied to move the cell stack into the housing tray, and optionally, wherein the downward force is applied transverse to a compressive force applied to the cell stack during the inserting.