Battery array frame design with ratchet retention features

Abstract

A battery pack includes a battery cell group and a plurality of array frames for holding the battery cell group. Each of the plurality of array frames includes a ratchet feature. A stud includes a raised surface configured to mate with the ratchet feature of each of the plurality of array frames to secure the plurality of array frames together.

Description

Technical Field

[0001] The present disclosure relates to battery packs for electric vehicles. An exemplary battery pack includes an array frame for holding at least one battery cell. The array frame includes a ratchet feature for engaging a stud. Background Art

[0002] The desire to reduce fuel consumption and emissions from motor vehicles has been well documented. As a result, vehicles are being developed that reduce or completely eliminate reliance on internal combustion engines. Electric vehicles are currently being developed for this purpose. In general, electric vehicles differ from conventional motor vehicles in that they are selectively driven by one or more battery-powered electric motors. In contrast, conventional motor vehicles rely entirely on internal combustion engines to propel the vehicle.

[0003] High voltage battery packs typically power the motors and other electrical loads of electric vehicles. The battery pack includes multiple battery cells that store energy for powering these electrical loads. The battery cells are typically packaged together in one or more assemblies using various support structures (e.g., frames, fasteners, bolts, rods, spacers, rails, walls, plates, bindings, etc.). These support structures may not apply consistent clamping force to the battery cells, resulting in inconsistent battery stack sizes and packaging challenges. Summary of the invention

[0004] Among other aspects, a battery pack according to an exemplary aspect of the present disclosure includes a battery cell group and a plurality of array frames for holding the battery cell group. Each of the plurality of array frames includes a ratchet feature. The stud includes a raised surface configured to match the ratchet feature of each of the plurality of array frames to secure the plurality of array frames together.

[0005] In a further non-limiting embodiment of the foregoing battery pack, each of the plurality of array frames includes a top wall, a bottom wall, and a frame arm extending between the top wall and the bottom wall.

[0006] In a further non-limiting embodiment of any of the foregoing battery packs, a securing strap is formed at a junction between the top wall or the bottom wall and one of the frame arms.

[0007] In a further non-limiting embodiment of any of the foregoing battery packs, the securing strap includes a side opening for receiving a stud.

[0008] In a further non-limiting embodiment of any of the foregoing battery packs, a first fastening strip is formed at a junction between the top wall and one of the frame arms, and a second fastening strip is formed at a junction between the bottom wall and one of the frame arms.

[0009] In a further non-limiting embodiment of any of the foregoing battery packs, each of the plurality of array frames includes a fastening strap having a side opening for receiving a stud.

[0010] In a further non-limiting embodiment of any of the foregoing battery packs, the ratchet feature is formed by a protruding wall of a fastening strap of at least one of the plurality of array frames.

[0011] In a further non-limiting embodiment of any of the foregoing battery packs, the protruding wall includes a first lip extending from an upper protrusion of the fastening strap and a second lip extending from a lower protrusion of the fastening strap.

[0012] In a further non-limiting embodiment of any of the foregoing battery packs, a curved surface is connected between the first lip and the second lip.

[0013] In a further non-limiting embodiment of any of the foregoing battery packs, the first lip and the second lip abut against a raised surface of the stud to limit movement of the plurality of array frames relative to the stud.

[0014] In a further non-limiting embodiment of any of the foregoing battery packs, the battery cell group and the plurality of array frames form a battery assembly.

[0015] In a further non-limiting embodiment of any of the foregoing battery packs, the opposing end plates are located within a longitudinal extent of the battery assembly.

[0016] In a further non-limiting embodiment of any of the foregoing battery packs, a stud extends through an opening of each opposing end plate.

[0017] In a further non-limiting embodiment of any of the foregoing battery packs, the ratchet feature includes a lip that abuts the raised surface to limit movement of the plurality of array frames relative to the studs.

[0018] In a further non-limiting embodiment of any of the foregoing battery packs, the raised surface projects radially outward from the axis of the stud.

[0019] In addition to other aspects, a method according to another exemplary aspect of the present disclosure includes using column bolts to fix multiple array frames of a battery assembly together, wherein the multiple array frames include ratchet features that engage with a raised surface of the column bolts to limit movement of the multiple array frames relative to the column bolts.

[0020] In another non-limiting embodiment of the foregoing method, the method includes inserting studs into side openings of fastening straps of the plurality of array frames.

[0021] In a further non-limiting embodiment of any of the foregoing methods, the method includes moving the plurality of array frames along an axis of the stud until the ratchet features abut a raised surface of the stud.

[0022] In a further non-limiting embodiment of any of the foregoing methods, the ratchet feature includes first and second lips that abut the raised surface to limit movement.

[0023] In a further non-limiting embodiment of any of the foregoing methods, the method includes inserting a stud through an opening of an end plate of the battery assembly.

[0024] The embodiments, examples and alternatives of the preceding paragraphs, claims or the following description and drawings include any of their various aspects or individual features, which can be made independently or in any combination. Features described in conjunction with one embodiment are applicable to all embodiments, unless these features are incompatible.

[0025] The various features and advantages of the present 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 schematically illustrates a powertrain system for an electric vehicle;

[0027] Figure 2 A battery assembly for an electric vehicle battery pack is shown;

[0028] Figure 3 yes Figure 2 an enlarged view of a portion of a battery assembly;

[0029] Figure 4 is a cross-sectional view through a plurality of interconnected array frames of a battery assembly;

[0030] Figure 5 is to depict studs and Figure 4 Another cross-sectional view of the connections between multiple interconnected array frames. DETAILED DESCRIPTION

[0031] The present disclosure details various battery pack designs for use within an electric vehicle. An exemplary battery pack includes a group of battery cells held in a battery stack by a plurality of interconnected array frames. Each array frame may include a ratchet feature configured to mate with a raised surface of a stud to secure the plurality of array frames together. The array frame / stud interface locks the array frame in position and limits relative movement of the array frame relative to the stud. These and other features are discussed in more detail in the following paragraphs of this detailed description.

[0032] Figure 1Schematically illustrated is a powertrain 10 for an electric vehicle 12. Although depicted as a Hybrid Electric Vehicle (HEV), it should be understood that the concepts described herein are not limited to HEVs and may extend to other electric vehicles, including, but not limited to, Plug-in Hybrid Electric Vehicles (PHEV), Battery Electric Vehicles (BEV), Fuel Cell Vehicles, etc.

[0033] In a non-limiting embodiment, the powertrain 10 is a power split powertrain that employs a first and a second drive system. The first drive system includes a combination of an engine 14 and a generator 18 (i.e., a first motor). The second drive system includes at least a motor 22 (i.e., a second motor), the generator 18, and a battery pack 24. In this example, the second drive system is considered to be the electric drive system of the powertrain 10. Both the first and second drive systems are capable of generating torque to drive one or more sets of vehicle drive wheels 28 of the electric vehicle 12. Although in Figure 1 A power split configuration is depicted in , but the present disclosure extends to any hybrid vehicle or electric vehicle including a full hybrid, parallel hybrid, series hybrid, mild hybrid, or micro hybrid.

[0034] The engine 14, which may be an internal combustion engine, and the generator 18 may be connected by a power transfer unit 30, such as a planetary gear set. Of course, other types of power transfer units, including other gear sets and transmissions, may be used to connect the engine 14 to the generator 18. In a non-limiting embodiment, the power transfer unit 30 is a planetary gear set including a ring gear 32, a sun gear 34, and a carrier assembly 36.

[0035] Generator 18 may be driven by engine 14 through power transfer unit 30 to convert kinetic energy into electrical energy. Generator 18 may alternatively be used as a motor to convert electrical energy into kinetic energy, thereby outputting torque to shaft 38 connected to power transfer unit 30. Because generator 18 is operatively connected to engine 14, the speed of engine 14 may be controlled by generator 18.

[0036] The ring gear 32 of the power transfer unit 30 can be connected to the shaft 40, and the shaft 40 is connected to the vehicle drive wheels 28 through the second power transfer unit 44. The second power transfer unit 44 can include a gear set having a plurality of gears 46. Other power transfer units may also be suitable. The gears 46 transfer torque from the engine 14 to the differential 48 to ultimately provide traction for the vehicle drive wheels 28. The differential 48 may include a plurality of gears capable of transferring torque to the vehicle drive wheels 28. In a non-limiting embodiment, the second power transfer unit 44 is mechanically connected to the shaft 50 through the differential 48 to distribute torque to the vehicle drive wheels 28.

[0037] The motor 22 can also be used to drive the vehicle drive wheels 28 by outputting torque to a shaft 52 that is also connected to the second power transfer unit 44. In a non-limiting embodiment, the motor 22 and the generator 18 cooperate as part of a regenerative braking system, where both the motor 22 and the generator 18 can be used as motors to output torque. For example, the motor 22 and the generator 18 can each output power to the battery pack 24.

[0038] The battery pack 24 is an exemplary electric vehicle battery. The battery pack 24 may be a high voltage traction battery pack that includes a plurality of battery assemblies 25 (i.e., a battery array or group of battery cells) capable of outputting electrical power to operate the motor 22, the generator 18, and / or other electrical loads of the electric vehicle 12. Other types of energy storage devices and / or output devices may also be used to power the electric vehicle 12.

[0039] In one non-limiting embodiment, the electric vehicle 12 has two basic operating modes. The electric vehicle 12 can be operated in an electric vehicle (EV) mode, in which the motor 22 is used for vehicle propulsion (usually without the assistance of the engine 14), thereby depleting the state of charge of the battery pack 24 to its maximum allowable discharge rate under certain driving modes / cycles. EV mode is an example of a charge-depleting mode of operation of the electric vehicle 12. During EV mode, the state of charge of the battery pack 24 can increase in certain circumstances, such as during regenerative braking. The engine 14 is generally off in the default EV mode, but can be operated as needed based on vehicle system conditions or with the operator's permission.

[0040] The electric vehicle 12 may additionally operate in a hybrid electric vehicle (HEV) mode, in which both the engine 14 and the motor 22 are used for vehicle propulsion. The HEV mode is an example of a charge-maintaining operating mode of the electric vehicle 12. During the HEV mode, the electric vehicle 12 may reduce propulsion use of the motor 22 in order to maintain the state of charge of the battery pack 24 at a constant or approximately constant level by increasing the propulsive force of the engine 14. In addition to the EV and HEV modes within the scope of the present disclosure, the electric vehicle 12 may also operate in other operating modes.

[0041] Figure 2 and Figure 3 A battery assembly 25 that can be used in an electric vehicle is schematically shown. For example, the battery assembly 25 can be Figure 1 The battery assembly 25 is a component of the battery pack 24 of the electric vehicle 12. The battery assembly 25 includes a plurality of battery cells 56, which store energy for powering various electrical loads of the electric vehicle 12. Figure 2 A specific number of battery cells 56 are depicted in the figure, but within the scope of the present disclosure, the battery assembly 25 may employ a greater or lesser number of battery cells. In other words, the present disclosure is not limited to Figure 2 The specific configuration shown in .

[0042] The battery cells 56 can be stacked side by side to build groups of battery cells 56, sometimes referred to as "battery stacks". In one embodiment, the battery cells 56 are lithium-ion pouch cells. However, battery cells having other geometries (cylindrical, prismatic, etc.), other chemistries (nickel metal hydride, lead acid, etc.), or both may alternatively be used within the scope of the present disclosure.

[0043] The battery cells 56 together with any support structures (e.g., array frames, spacers, rails, walls, plates, bindings, etc.) may be collectively referred to as a battery assembly 25. In one embodiment, the battery cells 56 of the battery assembly 25 are supported, held and / or held together by a support structure 57 disposed around the outer periphery of the battery stack. The support structure 57 may include a plurality of interconnected array frames 58 and opposing end plates 60. The array frames 58 are stacked side by side, assembled together and positioned between opposing end plates 60, which are positioned in the longitudinal extent of the battery assembly 25. Thus, the battery assembly 25 extends along a longitudinal axis A1 between the opposing end plates 60. The array frames 58 each extend along a longitudinal axis A2 that is substantially transverse to the longitudinal axis A1.

[0044] Once the battery cells 56 have been positioned within the array frame 58, the terminals 61 of the battery cells 56 protrude laterally outwardly of the array frame 58. For example, the terminals 61 may be positioned to extend on the sides of the battery assembly 25 parallel to the longitudinal axis A2.

[0045] The support structure 57 may further include one or more studs 62 for axially constraining the battery assembly 25. In one embodiment, the support structure 57 includes four studs 62 extending longitudinally between the opposing end plates 60, wherein each stud 62 is positioned at the top and bottom of each side of the battery assembly 25. However, within the scope of the present disclosure, the battery assembly 25 may employ a greater or lesser number of studs. The studs 62 may generally extend parallel to the longitudinal axis A1 of the battery assembly 25.

[0046] In another embodiment, studs 62 extend through openings 64 formed near each corner 66 of the end plate 60. The studs 62 can be connected to each array frame 58 of the battery assembly 25. The studs 62 lock the positioning of the array frames 58 relative to each other to assemble the battery assembly 25 into a uniform unit. In one embodiment, as shown in FIG. Figure 3 As best shown, the stud 62 includes a raised surface 68 that cooperates (i.e., engages) with a ratchet feature 70 of each array frame 58 to provide a "zipper" effect during assembly of the battery assembly 25. As discussed in more detail below, the novel "zipper" design provided by the array frame 58 / stud 62 engagement locks the array frame in position and limits relative movement of the array frame 58 relative to the stud 62.

[0047] Figure 4 Shows Figure 2 The battery assembly 25 is shown with multiple interconnected array frames 58. Figure 4 Array frame 58 with battery cells 56 and studs 62 removed to better illustrate ratchet features 70 and various other structures of array frame 58 .

[0048] Each array frame 58 includes a frame body 72 disposed along a longitudinal axis A2 (see Figure 2 ). The frame body 72 may be rectangular in shape (i.e., quadrilateral) and include a top wall 74, a bottom wall 76, and a frame arm 78 connected between the top wall 74 and the bottom wall 76. In one embodiment, the frame arm 78 is disposed near the opposite ends (i.e., near the longitudinal extent) of the top wall 74 and the bottom wall 76. The top wall 74, the bottom wall 76, and the frame arm 78 form a boundary around an opening formed through the frame body 72. In one embodiment, the top wall 74 and the bottom wall extend horizontally and parallel to the longitudinal axis A2 of the frame body 72, and the frame arm 78 extends vertically and transversely to the longitudinal axis A2.

[0049] The frame body 72 of the array frame 58 can be a unitary plastic structure. In one embodiment, the top wall 74, the bottom wall 76 and the frame arms 78 are molded, cast, machined or otherwise manufactured to form a unitary one-piece structure.

[0050] Each opposing side of the frame body 72 may form a recess 82 sized and shaped to receive a battery cell (see, e.g., Figure 3 Each array frame 58 can accommodate one or two battery cells, and each recess 82 is capable of receiving a single battery cell 56.

[0051] Each array frame 58 may additionally include one or more fastening straps 84 for accommodating the studs 62. The fastening straps 84 are an integral feature of the frame body 72 of the array frame 58. The fastening straps 84 may protrude from the frame arms 78 in a direction away from the opening 80 of the frame body 72. In one embodiment, the fastening straps 84 are disposed at both ends of each frame arm 78 (e.g., near the junction between each frame arm 78 and the top wall 74 and near the junction between each frame arm 78 and the bottom wall 76). The fastening straps 84 extending near the top wall 74 may be referred to as upper fastening straps, while the fastening straps 84 extending near the bottom wall 76 may be referred to as lower fastening straps.

[0052] Each fastening strap 84 includes an upper protrusion 86 and a lower protrusion 88. The side opening 90 is generally parallel to the longitudinal axis A1 of the battery assembly 25 (see Figure 2 ) extends between the upper and lower projections 86, 88. The side opening 90 is sized and shaped to receive one of the studs 62 (see, e.g., Figure 2 and 5 ).

[0053] The fastening strips 84 form ratchet features 70 of the array frame 58. In one embodiment, each ratchet feature 70 is provided by a protruding wall 92 that protrudes inwardly from both the upper and lower protrusions 86, 88 of the fastening strip. The protruding wall 92 may include a first lip 94 extending inwardly from the upper protrusion 86, a second lip 96 extending inwardly from the lower protrusion 88, and a curved surface 98 connected between the first and second lip 94, 96.

[0054] Now refer to Figure 4 and Figure 5 , the raised surface 68 of the stud 62 extends radially outward from the shaft 100. Once the stud 62 is inserted into the side opening 90 of the tightening band 84, the curved surface 98 of the protruding wall 92 receives the shaft 100 of the stud 62. In one embodiment, the shaft 100 of the stud 62 is hollow to reduce weight.

[0055] The stud 62 may be positioned within the side opening 90 of the fastening band 84. The array frame 58 may then be pushed in the direction of arrow 99 to assemble the battery assembly 25. Moving the array frame 58 in the direction of arrow 99 causes the first lip 94 and the first lip 96 of the protruding wall 92 to abut against the raised surface 68 of the stud 62, thereby creating a "zipper" effect and limiting relative movement between the array frame 58 and the stud 62. Once the end plate 60 (see FIG. 1 ) is added, the array frame 58 may be moved in the direction of arrow 99 to assemble the battery assembly 25. Figure 2 ), the column bolts 62 effectively apply a compressive locking force on multiple array frames 58.

[0056] The array frame / stud ratchet mating feature described in the present disclosure improves module functionality by locking the frame relative to the bolt movement, thereby improving battery assembly robustness without the need for additional components. As a result, the relative separation of the frame and end plates is significantly reduced, which may result in improved vibration characteristics and increased durability.

[0057] Although different non-limiting embodiments are shown as having specific components or steps, the embodiments of the present disclosure are not limited to those specific combinations. Some components or features in any non-limiting embodiment may be used in combination with features or components from any other non-limiting embodiment.

[0058] It should be understood that like reference numerals indicate corresponding or similar elements throughout the several drawings.It should be understood that although particular component arrangements are disclosed and illustrated in these exemplary embodiments, other arrangements may also benefit from the teachings of the present disclosure.

[0059] The above description should be interpreted as illustrative, rather than any limitation. It will be appreciated by those skilled in the art that some modifications may fall within the scope of the present disclosure. For these reasons, the following claims should be studied to determine the true scope and content of the present disclosure.

Claims

1. A battery pack comprising: Battery cell group; a plurality of array frames for holding the battery cell group, wherein each of the plurality of array frames includes a ratchet feature; and a stud including a raised surface configured to mate with the ratchet feature of each of the plurality of array frames to secure the plurality of array frames together, in, Each of the plurality of array frames includes a fastening strap having a side opening for receiving the stud and including the ratchet feature. 2 . The battery pack of claim 1 , wherein each of the plurality of array frames comprises a top wall, a bottom wall, and a frame arm extending between the top wall and the bottom wall. 3 . The battery pack of claim 2 , wherein the fastening strap is formed at a junction between the top wall or the bottom wall and one of the frame arms.

4. The battery pack of claim 2, comprising a first fastening strap formed at a junction between the top wall and one of the frame arms and a second fastening strap formed at a junction between the bottom wall and one of the frame arms. 5 . The battery pack according to claim 1 , wherein the fastening bands of adjacent array frames of the plurality of array frames abut against each other to form the side opening for receiving the stud. 6 . The battery pack of claim 1 , wherein the ratchet feature is formed by a protruding wall of a fastening strap of at least one of the plurality of array frames. 7 . The battery pack of claim 6 , wherein the protruding wall includes a first lip extending from an upper protrusion of the fastening band and a second lip extending from a lower protrusion of the fastening band.

8. The battery pack of claim 7, comprising a curved surface connected between the first lip and the second lip. 9 . The battery pack of claim 8 , wherein the first lip and the second lip abut against the raised surface of the stud to limit movement of the plurality of array frames relative to the stud.

10. The battery pack of claim 1, wherein the battery cell group and the plurality of array frames form a battery assembly.

11. The battery pack of claim 10, comprising opposing end plates located within the longitudinal extent of the battery assembly.

12. The battery pack of claim 11, wherein the stud extends through an opening of each of the opposing end plates.

13. The battery pack of claim 1, wherein the ratchet feature comprises a lip that abuts the raised surface to limit movement of the plurality of array frames relative to the studs.

14. The battery pack of claim 1, wherein the raised surface projects radially outward from a shaft of the stud.

15. A method for a battery assembly, comprising: A plurality of array frames of a battery assembly are fixed together using studs, wherein the plurality of array frames include ratchet features that engage with raised surfaces of the studs to limit movement of the plurality of array frames relative to the studs, wherein: Each of the plurality of array frames includes a fastening strap having a side opening for receiving the stud and including the ratchet feature.

16. The method of claim 15, comprising inserting the studs into the side openings of the fastening straps of the plurality of array frames.

17. The method of claim 16, comprising moving the plurality of array frames along an axis of the stud until the ratchet feature abuts the raised surface of the stud.

18. The method of claim 15 or 16, wherein the ratchet feature comprises first and second lips that abut against the raised surface to limit the movement.

19. The method of claim 15, comprising inserting the stud through an opening of an end plate of the battery assembly.

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