Configuration for optimizing battery cell-to-bus bar electrical connection

Abstract

The present disclosure provides a configuration for optimizing battery cell to bus bar electrical connections. Battery cell tab terminals to bus bar configurations for electrically connecting battery cells within a traction battery pack are provided. The tab terminal may be secured to the bus bar within a space extending between the battery cells and the bus bar in order to reduce the amount of packaging space required to electrically connect the battery cells and thus reduce the overall tab terminal to bus bar footprint. In one implementation, the tab terminal is secured to a planar surface of the bus bar and forced into contact with the planar surface by a backplate. In other implementations, the tab terminal is secured to an angled portion of the bus bar.

Description

Technical Field

[0001] This disclosure generally relates to traction battery packs for electrified vehicles, and more specifically to technologies for electrically connecting battery cells to traction battery packs. Background Technology

[0002] High-voltage traction battery packs typically power the electric motors and other electrical loads of electrified vehicles. A traction battery pack comprises multiple battery cells. These cells must be reliably connected to each other to provide the voltage and electrical levels required to propel the vehicle. Summary of the Invention

[0003] An exemplary aspect of this disclosure includes a traction battery pack comprising a battery cell including a housing and a tab terminal extending from the housing. The tab terminal includes a bent tab end portion, a busbar arranged adjacent to the bent tab end portion, a backplate receiving the bent tab end portion, and a weld portion securing the bent tab end portion to the busbar.

[0004] In another non-limiting embodiment of the aforementioned traction battery pack, the welded portion is a laser-welded portion.

[0005] In yet another non-limiting embodiment of any of the aforementioned traction battery packs, the weld is formed on the flat surface of the busbar to engage with the curved tab end portion of the battery cell.

[0006] In yet another non-limiting embodiment of any of the aforementioned traction battery packs, the backplate is configured to provide a force for pushing the curved tab end section into a suitable welding position relative to the first flat surface of the busbar.

[0007] In another non-limiting embodiment of any of the aforementioned traction battery packs, the curved tab end section is pushed against the angled surface of the back plate by a comb-like structure.

[0008] In yet another non-limiting embodiment of any of the aforementioned traction battery packs, the comb-like structure includes a slot for receiving the tab terminals. The slot is surrounded by a soft surface.

[0009] In yet another non-limiting embodiment of any of the aforementioned traction battery packs, the backplate is part of a busbar frame fixed to the busbar. The busbar frame and the busbar together form the busbar module of the traction battery pack.

[0010] In yet another non-limiting embodiment of any of the aforementioned traction battery packs, the curved tab end section includes a proximal tip portion and a distal tip portion, the distal tip portion being folded around the curved portion toward the proximal tip portion.

[0011] In yet another non-limiting embodiment of any of the aforementioned traction battery packs, the proximal tip portion extends in a first plane, and the housing of the battery cell extends in a second plane, which is approximately perpendicular to the first plane.

[0012] In yet another non-limiting embodiment of any of the aforementioned traction battery packs, the curved portion is received against the angled surface of the backplate.

[0013] In yet another non-limiting embodiment of any of the aforementioned traction battery packs, the welded portion has a pair of viewing windows extending through the body of the busbar on both sides.

[0014] A traction battery pack according to another exemplary aspect of this disclosure particularly includes: a battery cell including a housing and tab terminals extending from the housing; a busbar including a flared portion extending in a direction toward the housing of the battery cell to a position adjacent to the tab terminals; and a weld portion securing the tab terminals to the flared portion.

[0015] In another non-limiting embodiment of the aforementioned traction battery pack, the flared portion is disposed at the opening of the busbar.

[0016] In yet another non-limiting embodiment of any of the aforementioned traction battery packs, the flared portion extends in the direction toward the battery cell.

[0017] In yet another non-limiting embodiment of any of the aforementioned traction battery packs, the tab end portion of the tab terminal is received against the angled surface of the flared portion.

[0018] In yet another non-limiting embodiment of any of the aforementioned traction battery packs, the weld joins the tab end portion to the angled surface.

[0019] In yet another non-limiting embodiment of any of the aforementioned traction battery packs, the tab end portion, when fixed by the welded portion, is located in the space between the busbar and the housing of the battery cell.

[0020] In yet another non-limiting embodiment of any of the aforementioned traction battery packs, the angled surface provides a flat welding surface for joining the tab end segment to the flared portion.

[0021] In yet another non-limiting embodiment of any of the aforementioned traction battery packs, the proximal tip portion of the tab end segment extends in a first plane, and the housing of the battery cell extends in a second plane, which is greater than perpendicular to the first plane.

[0022] In yet another non-limiting embodiment of any of the aforementioned traction battery packs, the busbar is made of a first metal material, and the tab terminal is made of a second metal material different from the first metal material.

[0023] The embodiments, examples, and alternatives (including any of their various aspects or corresponding features) described in the foregoing paragraphs, claims, or the following description and drawings may be used independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments unless such features are incompatible.

[0024] Various features and advantages of this disclosure will become apparent to those skilled in the art from the following detailed description. The accompanying drawings, which briefly describe the specific embodiments, are as follows. Attached Figure Description

[0025] Figure 1 An electric vehicle is shown schematically.

[0026] Figure 2 This is a perspective view of the traction battery pack of an electric vehicle.

[0027] Figure 3 yes Figure 2 A schematic cross-sectional view of the height of the traction battery pack.

[0028] Figure 4 The battery cells used in the traction battery pack are shown.

[0029] Figure 5 A busbar module configured to connect the tab terminals of a group of battery cells is shown.

[0030] Figure 6 Is it through Figure 5 The cross-sectional view of section 6-6.

[0031] Figure 7 An exemplary shape of the end section of the battery cell tab terminal is shown.

[0032] Figure 8 This is a cross-sectional view of an exemplary busbar used to connect the tab terminals of a group of battery cells.

[0033] Figure 9 yes Figure 8 A perspective view of the busbar. Detailed Implementation

[0034] This disclosure describes in detail an exemplary battery cell tab terminal to busbar configuration for electrically connecting battery cells within a traction battery pack. The tab terminals are secured to the busbar within a space extending between the battery cell and the busbar to reduce the amount of encapsulation space required for electrically connecting the battery cell and thus reduce the overall tab terminal to busbar coverage area. In one implementation, the tab terminals are secured to a flat surface of the busbar and forced into contact with the flat surface by a backplate. In other implementations, the tab terminals are secured to an angled portion of the busbar. These and other features are discussed in more detail in the following paragraphs of this specific embodiment.

[0035] Figure 1 An electrified vehicle 10 is schematically illustrated. The electrified vehicle 10 may include any type of electrified powertrain. In this embodiment, the electrified vehicle 10 is a battery electric vehicle (BEV). However, the concepts described herein are not limited to BEVs and can be extended to other electrified vehicles, including but not limited to hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles, etc. Therefore, although not specifically shown in the exemplary embodiments, the powertrain of the electrified vehicle 10 may be equipped with an internal combustion engine, which may be used alone or in combination with other power sources to propel the electrified vehicle 10.

[0036] In the illustrated embodiment, the electrified vehicle 10 is depicted as an automobile. However, the electrified vehicle 10 may alternatively be a sports utility vehicle (SUV), van, pickup truck, or any other vehicle configuration. Although specific component relationships are shown in the accompanying drawings of this disclosure, the illustrations are not intended to limit the scope of this disclosure. The placement and orientation of the various components of the electrified vehicle 10 are schematically shown and may vary within the scope of this disclosure. Furthermore, the various drawings accompanying this disclosure are not necessarily drawn to scale, and some features may be enlarged or minimized to emphasize certain details of particular components or systems.

[0037] In the illustrated embodiment, the electrified vehicle 10 is a purely electric vehicle propelled solely by electricity (such as by one or more motors 12) without the assistance of an internal combustion engine. The motor 12 may operate as an electric motor, a generator, or both. The motor 12 receives electricity and can convert it into torque for driving one or more wheels 14 of the electrified vehicle 10.

[0038] Voltage bus 16 can electrically connect motor 12 to traction battery pack 18. Traction battery pack 18 is an exemplary electric vehicle battery. Traction battery pack 18 can be a high-voltage traction battery pack assembly including multiple battery cells capable of outputting power to supply motor 12 and / or other electrical loads of electric vehicle 10. Other types of energy storage devices and / or output devices may alternatively or additionally be used to supply power to electric vehicle 10.

[0039] The traction battery pack 18 can be fixed to the bottom 20 of the electric vehicle 10. However, within the scope of this disclosure, the traction battery pack 18 can be located elsewhere on the electric vehicle 10.

[0040] Figure 2 and Figure 3 Additional details associated with the traction battery pack 18 of the electrified vehicle 10 are shown. The traction battery pack 18 may include one or more battery arrays 22 (e.g., battery assemblies or groups of rechargeable battery cells 24) capable of outputting power to supply the motor 12 and / or other electrical loads of the electrified vehicle 10. Other types of energy storage devices and / or output devices may alternatively or additionally be used to supply power to the electrified vehicle 10.

[0041] Battery cells 24 can be stacked side-by-side along the stacking axis to form a group of battery cells 24, sometimes referred to as a "cell stack". Figure 3 In the highly schematic depiction, battery cells 24 are stacked in the direction of entry into the page to form each battery array 22, and thus the battery array 22 can extend in the lateral direction of the vehicle. However, other configurations are also possible. The total number of battery arrays 22 and battery cells 24 provided within the traction battery pack 18 is not intended to limit this disclosure.

[0042] In this embodiment, the battery cell 24 of each battery array 22 is a pouch-type lithium-ion cell. However, battery cells having other geometries (cylindrical, prismatic, etc.), other chemical substances (nickel-metal hydride, lead acid, etc.), or both may be used alternatively within the scope of this disclosure.

[0043] Battery array 22 and various other internal battery components (e.g., bus electrical center, battery control module, wiring, connectors, etc.) can be housed in internal region 26 of housing assembly 28 (see Figure 3 The housing assembly 28 may include a housing cover 30 and a housing tray 32. The housing cover 30 may be secured (e.g., bolted, welded, adhered, etc.) to the housing tray 32 to provide the interior area 26. The size, shape, and overall configuration of the housing assembly 28 are not intended to limit this disclosure.

[0044] Figure 4One of the battery cells 24 that may be disposed within a traction battery pack 18 is shown. Each battery cell 24 may include a housing 36 and a pair of tab terminals 34 projecting outward from the housing 36. In an embodiment, each battery cell 24 includes two tab terminals 34, with one tab terminal 34 projecting outward at each opposite side of the housing 36. One of the tab terminals 34 provides a positive terminal for the battery cell 24, and the other tab terminal 34 provides a negative terminal for the battery cell 24. However, other configurations are contemplated within the scope of this disclosure.

[0045] The tab terminals 34 of the battery cells 24 in each battery array 22 must be reliably connected to each other to provide the voltage and power levels required for vehicle propulsion. Busbars are sometimes used for these connections; however, proper positioning and alignment of the tab terminals 34 relative to the busbars can be difficult during assembly and welding processes. Furthermore, busbars are typically thicker than the tab terminals 34, introducing welding complexities that can lead to burn-through and / or welding spatter. Additionally, some weld joint designs for electrical connection busbars may be oriented to occupy excessive volume or encapsulation space within the battery array 22 or traction battery pack 18. Therefore, this disclosure specifically relates to tab terminal and busbar shape variations that can be used to optimize the battery cell-to-busbar electrical connections and thus reduce the encapsulation space required for each battery array 22.

[0046] Figure 5 and Figure 6 A busbar 38 is shown, which can be coupled to the tab terminals 34 of a group of battery cells 24 for electrical connection of the battery cells 24. For example, the group of battery cells 24 may be part of one of the battery arrays 22 of a traction battery pack 18. Once electrically connected, the battery cells 24 can supply power to power various components of the electrified vehicle 10.

[0047] The tab terminal 34 and busbar 38 can be metal components. In an embodiment, the busbar 38 is made of copper or aluminum, and the tab terminal is made of aluminum. However, other materials or combinations of materials are contemplated within the scope of this disclosure.

[0048] The tab terminals 34 can be joined to the first flat surface 40 of the busbar 38 via one or more welding portions 42 (e.g., laser welding portions). The first flat surface 40 may face toward the housing 36 of the battery cell 24, and the second flat surface 41 of the busbar 38 may face away from the housing 36. The welding portions 42 may be linear welding portions, non-linear welding portions, or any other welding portion pattern. A laser beam (e.g., from a welding tool) may pass through an opening in the busbar 38 to form the welding portions 42, thereby joining the busbar 38 to the tab terminals 34 of the battery cell 24.

[0049] The busbar 38 may include a plurality of viewing windows 44. Each viewing window 44 may be formed through the body 45 of the busbar 38 and is configured to allow one or more of the tab terminals 34 to be seen from the side of the busbar 38 opposite to the battery cell 24 (i.e., from the outside of the second flat surface 41). In an embodiment, each weld 42 has a pair of viewing windows 44 on both sides.

[0050] The shape of each tab terminal 34 can be specifically designed to optimize the electrical connection from the battery cell to the busbar. For example, as Figure 7 As shown, each tab terminal 34 may include a proximal tab section 58 extending from an internal electrode of the cell to the exterior of the housing 36 of the battery cell 24. The proximal tab section 58 may be substantially straight along its length. The tab terminal 34 may additionally include a first bend 62 that positions the tab end section 60 at an angle relative to the proximal tab section 58. The tab end section 60 may include a proximal tip portion 66 and a distal tip portion 68. The distal tip portion 68 may fold toward the proximal tip portion 66 around a second bend 70. Once folded, the distal tip portion 68 may contact or be slightly spaced from the proximal tip portion 66.

[0051] The proximal tip portion 66, the distal tip portion 68, and the second bend 70 together form a crimping portion 72 of the tab end section 60. The crimping portion 72 provides a localized increase in thickness at the tab end section 60 of the tab terminal 34. Therefore, during the process of welding the tab end section 60 of the tab terminal 34 to the busbar 38, the tab terminal 34 is less likely to be soldered through and welding spatter in the direction toward the battery cell 24 is effectively limited.

[0052] Currently, the main reference is... Figure 6 The backplate 46 facilitates the positioning and placement of the tab terminals 34 relative to the first flat surface 40 of the busbar 38 during assembly and soldering operations. The backplate 46 may include an angled surface 48 sized to receive the tab end portion 60 of the tab terminal 34 and push the tab end portion 60 into a suitable soldering position relative to the first flat surface 40 of the busbar 38 via a reaction force F1. A second bend 70 of the tab end portion 60 may be received directly abutting against the angled surface 48.

[0053] Backplate 46 may be a busbar frame 50 that can be attached to busbar 38 (see...) Figure 5 It is part of the busbar module 52, which is formed by busbar 38 and busbar frame 50.

[0054] The position of the tab terminal 34 along the length L of the busbar 38 can be adjusted using the comb-like structure 54. The comb-like structure 54 may include a slot 56, the size of which is determined to receive the tab terminal 34. The comb-like structure 54 can be moved along a first direction D1 or a second direction D2 to change the position of the tab terminal 34 relative to the busbar 38. The first direction D1 and the second direction D2 extend parallel to the length L of the busbar 38.

[0055] The slot 56 may be surrounded by a soft surface 64 of the comb-like structure 54. The soft surface 64 may be made of foam or some other soft material, which prevents damage to the tab terminals 34 when the comb-like structure 54 moves along the first direction D1 or the second direction D2 during assembly.

[0056] When the comb-like structure 54 moves along the second direction D2, the flexible surface 64 can apply a force F2 to the tab terminal 34 to push the tab end section 60 against the angled surface 48 of the back plate 46 to engage. Therefore, the combination of force F2 and reaction force F1 can serve as a clamping force for holding the terminal 34 between the busbar 38 and the back plate 46.

[0057] In one embodiment, the comb structure 54 is a temporary build jig that can be removed after the welding process is complete. In another embodiment, the comb structure 54 is incorporated as part of the busbar frame 50.

[0058] Once the tab end segment 60 has been moved to the appropriate welding position relative to the busbar 38 via the comb structure 54 and the backplate 46, the proximal tip portion 66 of the tab terminal 34 may extend in a first plane P1, which is angled at angle α relative to a second plane P2 extending through the housing 36 of the battery cell 24. In an embodiment, angle α is approximately 90 degrees. In this disclosure, the term “approximately” indicates that the expressed quantity or range does not need to be precise, but may be approximate and / or larger or smaller, thereby reflecting acceptable tolerances, conversion factors, measurement errors, etc. However, other angles are contemplated within the scope of this disclosure. By positioning the welding surface of the tab terminal 34 in the space 99 extending between the busbar 38 and the battery cell 24, the busbar 38 can be positioned closer to the housing 36 of the battery cell 24, thereby reducing the overall packaging space required for the battery array 22.

[0059] Figure 8 and Figure 9Another exemplary busbar 138 is shown, which can be engaged with tab terminals 34 of a group of battery cells 24 for electrical connection of the battery cells 24. The busbar 138 may include a plurality of flared portions 80 at which the tab terminals 34 may abut against the busbar 138. A flared portion 80 may be provided at each opening 82 formed through the busbar 138. In another embodiment, the opening 82 may be formed during stamping / forming of the flared portion 80.

[0060] Each flared portion 80 may extend in a direction toward the battery cell 24 of the battery cell assembly. The tab end portion 60 of the tab terminal 34 may be received abutting against the angled surface 86 of the flared portion 80. Each angled surface 86 may provide a relatively flat surface for creating one or more weld portions 42 for engaging the tab end portion 60 of the tab terminal 34 with the angled surface 86 of the flared portion 80.

[0061] When the tab end segment 60 has been moved to the appropriate welding position relative to the flared portion 80 of the busbar 138, the proximal tip portion 66 of the tab terminal 34 may extend in a first plane P1, which is angled at angle α relative to a second plane P2 extending through the housing 36 of the battery cell 24. In one embodiment, angle α is greater than 90 degrees. In another embodiment, angle α is approximately 120 degrees. However, other angles are contemplated within the scope of this disclosure.

[0062] By positioning the welding surface of the tab terminal 34 in the space 99 extending between the busbar 138 and the battery cell 24, the busbar 138 can be placed closer to the housing 36 of the battery cell 24, thereby reducing the overall packaging space required for the battery array 22.

[0063] The aforementioned exemplary tab terminal and busbar shape variations are designed to reduce the amount of packaging space required for electrical connection of the battery cells. The proposed design facilitates tab terminal-to-busbar connections that can be achieved by providing a solder surface located in the space between the battery cell housing and the busbar, thereby significantly reducing the overall coverage area of ​​the array.

[0064] While different non-limiting embodiments are shown having specific components or steps, the embodiments disclosed herein are not limited to these particular combinations. Some of the components or features from any of the non-limiting embodiments may be used in combination with features or components from any of the other non-limiting embodiments.

[0065] It should be understood that the same reference numerals identify corresponding or similar elements throughout all the figures. It should be understood that although particular arrangements of components are disclosed and shown in these exemplary embodiments, other arrangements may also benefit from the teachings of this disclosure.

[0066] The foregoing description should be interpreted as illustrative and not restrictive. Those skilled in the art will understand that certain modifications may be made within the scope of this disclosure. For these reasons, the appended claims should be examined to determine the true scope and content of this disclosure.

Claims

1. A traction battery pack, the traction battery pack comprising: A battery cell, the battery cell including a housing and tab terminals extending from the housing, wherein the tab terminals include bent tab end portions; A busbar, wherein the busbar is arranged adjacent to the bent tab end portion of the tab terminal; Backplate, the backplate receiving the curved electrode lug end section; as well as The welding part secures the curved tab end section to the busbar.

2. The traction battery pack of claim 1, wherein the welding portion secures the curved tab end portion to a first flat surface of the busbar, and optionally, wherein the backplate is configured to provide a force for pushing the curved tab end portion to a suitable welding position relative to the first flat surface of the busbar.

3. The traction battery pack of claim 2, wherein the weld is formed at the second flat surface of the busbar and penetrates both the second flat surface and the first flat surface to secure the curved tab end portion to the busbar.

4. The traction battery pack of any of the preceding claims, wherein the curved tab end portion is pushed against the angled surface of the back plate by a comb-like structure, and optionally, wherein the comb-like structure includes a slot for receiving the tab terminal, and further, wherein the slot is surrounded by a soft surface.

5. The traction battery pack of any of the preceding claims, wherein the backplate is part of a busbar frame fixed to the busbar, and further, wherein the busbar frame and the busbar form a busbar module of the traction battery pack.

6. The traction battery pack of any of the preceding claims, wherein the curved tab end portion includes a proximal tip portion and a distal tip portion, the distal tip portion being folded around the curved portion toward the proximal tip portion, and optionally, wherein the curved portion is received against an angled surface of the backplate.

7. The traction battery pack of claim 6, wherein the proximal tip portion extends in a first plane and the housing of the battery cell extends in a second plane, the second plane being approximately perpendicular to the first plane.

8. The traction battery pack as claimed in any of the preceding claims, wherein the welded portion has a pair of viewing windows extending through the body of the busbar on both sides.

9. A traction battery pack, the traction battery pack comprising: A battery cell, the battery cell including a housing and electrode terminals extending from the housing; A busbar, the busbar including a flared portion that extends in a direction toward the housing of the battery cell to a position adjacent to the tab terminal; as well as The welding part fixes the electrode terminal to the flared part.

10. The traction battery pack of claim 9, wherein the flared portion is disposed at the opening of the busbar.

11. The traction battery pack of claim 9 or 10, wherein the flared portion extends in a direction toward the battery cell, and optionally, wherein the tab end portion of the tab terminal is received abutting against an angled surface of the flared portion, and further, wherein the weld portion joins the tab end portion to the angled surface.

12. The traction battery pack of claim 11, wherein the tab end portion is located in the space between the busbar and the housing of the battery cell when fixed by the weld.

13. The traction battery pack of claim 11, wherein the angled surface provides a flat welding surface for joining the tab end segment to the flared portion.

14. The traction battery pack of claim 11, wherein the proximal tip portion of the tab end segment extends in a first plane, and the housing of the battery cell extends in a second plane, the second plane being greater than perpendicular to the first plane.

15. The traction battery pack of any one of claims 9 to 14, wherein the busbar is made of a first metal material and the tab terminal is made of a second metal material different from the first metal material.

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