Battery cell tab with frangible region

Abstract

The present disclosure provides a battery cell tab with a frangible region. A battery assembly includes: a pouch housing an electrode structure; and a tab electrically coupling the electrode structure to a device outside the pouch. And the tabs extend from the inside of the soft package to the outside of the soft package. And the tab comprises a fragile area. And the tab membrane at least covers the fragile area of the tab.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to a tab of a pouch-style battery cell, and more particularly to a tab having a frangible region. BACKGROUND

[0002] Electrically powered vehicles include a traction battery pack for powering the electric motor and other electrical loads of the vehicle. The traction battery pack includes a plurality of battery cells and various other battery internal components that support the propulsion of the electric vehicle. SUMMARY

[0003] In some aspects, the technology described herein relates to a battery assembly comprising: a housing containing an electrode structure; a tab electrically coupling the electrode structure to a device external to the housing, the tab extending from an interior of the housing to an exterior of the housing, the tab comprising a frangible region; and a tab film covering at least the frangible region of the tab.

[0004] In some aspects, the technology described herein relates to a battery assembly wherein the frangible region comprises a plurality of holes extending through a thickness of the tab.

[0005] In some aspects, the technology described herein relates to a battery assembly wherein each hole within the plurality of holes has a diamond-shaped profile.

[0006] In some aspects, the technology described herein relates to a battery assembly wherein the electrode structure is sealed within the housing.

[0007] In some aspects, the technology described herein relates to a battery assembly wherein the frangible region provides a fuse.

[0008] In some aspects, the technology described herein relates to a battery assembly wherein the frangible region is completely covered by the tab film.

[0009] In some aspects, the technology described herein relates to a battery assembly wherein the tab film is polypropylene.

[0010] In some aspects, the technology described herein relates to a battery assembly wherein the frangible region is sandwiched by the tab film.

[0011] In some aspects, the technology described herein relates to a battery assembly wherein the device external to the housing is a busbar of a traction battery pack.

[0012] In some aspects, the technology described herein relates to a battery assembly wherein the frangible region comprises an array of holes extending through the tab.

[0013] In some aspects, the technology described herein relates to a battery assembly, wherein the frangible region is configured to rupture in response to a current higher than a threshold current.

[0014] In some aspects, the technology described herein relates to a battery assembly, wherein the frangible region is configured to rupture to interrupt a current flow through the tab.

[0015] In some aspects, the technology described herein relates to a battery assembly, wherein the frangible region comprises at least one slot to a side of the tab.

[0016] In some aspects, the technology described herein relates to a battery assembly, wherein the tab is a positive tab.

[0017] In some aspects, the technology described herein relates to a battery circuit interruption method, the battery circuit interruption method comprising: directing a current flow through a tab of a battery, the tab connecting an electrode of the battery located within a housing of the battery to an electrical component external to the housing; and covering a frangible region of the tab with a tab film, the frangible region configured to rupture in response to an overcurrent condition to interrupt the current flow through the tab.

[0018] In some aspects, the technology described herein relates to a battery circuit interruption method, wherein the frangible region is completely covered by the tab film.

[0019] In some aspects, the technology described herein relates to a battery circuit interruption method, wherein the battery is a soft-pack battery.

[0020] In some aspects, the technology described herein relates to a battery circuit interruption method, wherein the frangible region comprises a region of the tab having a plurality of holes.

[0021] In some aspects, the technology described herein relates to a battery circuit interruption method, wherein the plurality of holes each extend through a thickness of the tab.

[0022] In some aspects, the technology described herein relates to a battery circuit interruption method, wherein the battery is a soft-pack battery.

[0023] 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, can be taken independently or in any combination of one another. Features described in connection with one embodiment are applicable to all embodiments unless such features are incompatible. BRIEF DESCRIPTION OF DRAWINGS

[0024] The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description, which follows, taken in conjunction with the accompanying drawings. The accompanying drawings are briefly described as follows:

[0025] Figure 1 A side view of an electrified vehicle is shown in accordance with example embodiments of the disclosure.

[0026] Figure 2 A schematic perspective view of a battery pack of an electrified vehicle is shown from Figure 1 with the cover removed to show the battery cells within the interior region of the battery.

[0027] Figure 3 A battery cell of the battery pack of Figure 2 with the soft pack open.

[0028] Figure 4 A battery cell of the battery pack of Figure 3 with the soft pack closed.

[0029] Figure 5 A close-up view of the region of Figure 4 is shown with selected portions cut away to show the frangible region within the tab of the battery cell.

[0030] Figure 6 A top view of the region of Figure 5 is shown.

[0031] Figure 7 A cross-sectional view at line 7-7 in Figure 6 is shown.

[0032] Figure 8A and Figure 8B show a top view and a cross-sectional view of a tab having a frangible region in accordance with another example aspect of the invention.

[0033] Figure 9A and Figure 9B show a top view and a cross-sectional view of a tab having a frangible region in accordance with yet another example aspect of the invention.

[0034] Figure 10A and Figure 10B show a top view and a cross-sectional view of a tab having a frangible region in accordance with yet another example aspect of the invention. DETAILED DESCRIPTION

[0035] The present disclosure details a tab design for a soft pack battery cell. The tab includes a frangible region that can be activated to interrupt the flow of electrical current through the tab. The frangible region is covered to protect the frangible region and prevent accidental activation.

[0036] Figure 1 An electrified vehicle 10 is illustratively shown. The electrified vehicle 10 can include any type of electrified powertrain. In an 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), and the like. Thus, although not specifically shown in the example embodiments, the powertrain of the electrified vehicle 10 can be equipped with an internal combustion engine that can be employed alone or in combination with other power sources to propel the electrified vehicle 10.

[0037] In the illustrated embodiment, the electrified vehicle 10 is depicted as a car. However, the electrified vehicle 10 can alternatively be a sport utility vehicle (SUV), a van, a pickup truck, or any other vehicle configuration.

[0038] Although specific component relationships are shown in the drawings of the present disclosure, the drawings are not intended to limit the present disclosure. The placement and orientation of the various components of the electrified vehicle 10 are illustratively shown and can vary within the scope of the present disclosure. Additionally, the various drawings attached to the present disclosure are not necessarily drawn to scale, and some features can be exaggerated or minimized to emphasize certain details of the particular component, assembly, or system.

[0039] In the illustrated embodiment, the electrified vehicle 10 is a pure electric vehicle that is 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 can operate as an electric motor, a generator, or both. The electric machine 12 receives electric power and can convert the electric power to torque for driving one or more wheels 14 of the electrified vehicle 10.

[0040] A voltage bus 16 electrically couples the electric machine 12 to a traction battery pack 18. The traction battery pack 18 is a high-voltage traction battery pack assembly that includes a plurality of battery cells capable of outputting electric power to power the electric machine 12 and / or other electrical loads of the electrified vehicle 10.

[0041] The example traction battery pack 18 is fixed to a vehicle body floor 20 of the electrified vehicle 10. However, in other examples, the traction battery pack 18 can be located elsewhere on the electrified vehicle 10.

[0042] Referring to Figure 2 The traction battery pack 18 includes a plurality of cell stacks 22 housed within an interior region 30 of a housing. Here, the cell stacks 22 are assembled within a housing tray 34 that can be fixed to a housing cover, the vehicle body floor 20, or both to enclose the cell stacks 22 and other battery internal components within the interior region 30.

[0043] Each cell stack 22 includes a plurality of battery cells 36 stacked side-by-side relative to each other along the respective cell stack axis. The cell stack 22 is disposed on the base plate of the housing tray 34. A heat exchange plate (not shown) may be sandwiched between the base plate 40 and the cell stack 22.

[0044] In an exemplary embodiment, battery cell 36 is a lithium-ion pouch cell. Battery cells having other geometries and / or chemical compositions (nickel-metal hydride, lead-acid, etc.) may alternatively be used within the scope of this disclosure.

[0045] refer to Figure 3 and Figure 4 And continue to refer to Figure 2 The battery cell 36 includes an electrode structure 50 housed within a housing 54. A positive tab 58 and a negative tab 62 extend into the interior 64 of the housing 54 and are electrically connected to the electrode structure 50.

[0046] The positive tab 58 can be connected to the cathode foil of the electrode structure 50. The positive tab 58 can be aluminum, but other materials can be used. The negative tab 62 can be connected to the anode foil of the electrode structure 50. In this example, the negative tab 62 is copper, but other materials can be used.

[0047] In this example, the positive tab 58 and the negative tab 62 extend from opposite sides of the housing 54. In another example, the positive tab 58 and the negative tab 62 are on the same side of the housing 54.

[0048] The housing 54 may be a laminated film, such as a laminated aluminum film, which is folded over the electrode structure 50 to position the electrode structure 50 within the interior 64 of the housing 54. The sides 66 of the housing 54 are then sealed to enclose the electrode structure 50 within the interior of the housing 54.

[0049] Positive tab 58 and negative tab 62 extend from electrode structure 50 through corresponding sides 66 of housing 54 to locations outside housing 54. Positive tab 58 and negative tab 62 can each be connected to another device 70, 72 outside housing 54. For example, as... Figure 2 As shown, the positive tab 58 can extend through a hole 74 in the transverse member 76 of the battery pack 18 to connect to the busbar 78 of the battery pack 18. Spot welding can be used to connect the positive tab 58 to another device 70.

[0050] Now for reference Figures 5 to 7 And continue to refer to Figure 4The battery cell 36 includes a tab film 80 that sandwiches a portion of the positive tab 58 in between, where the positive tab 58 extends through the side 66. The tab film 80 extends continuously circumferentially around the entire perimeter of the positive tab 58. The tab film 80 can be polypropylene. In other examples, the tab film 80 can be polyimide, polyethylene, polyethylene terephthalate, etc.

[0051] The tab film 80 helps seal the housing 54 where the positive tab 58 extends through the side 66. The seal provided by the tab film 80 can help prevent leakage of electrolyte, for example, where the positive tab extends through the side 66. The tab film 80 can also prevent a short circuit between the positive tab 58 and the housing 54.

[0052] It can be appreciated that another tab film 80 can be used in conjunction with the negative tab 62 to seal the housing 54 where the negative tab 62 extends through the side 66.

[0053] In this example, the positive tab 58 includes a frangible region 84. The frangible region 84 can be a plurality of holes 88. The holes 88 can have a diamond-shaped profile, a circular profile, or another profile. In this example, the holes 88 extend through the thickness T of the positive tab 58. In another example, the holes 88 only partially extend through the thickness T.

[0054] When directing a current flow through the positive tab 58, the frangible region 84 will rupture to interrupt the current flow through the positive tab 58 if an electrical parameter associated with the positive tab 58, such as a current level, exceeds a threshold level. Thus, the frangible region 84 provides a fuse that ruptures in response to an overcurrent condition. The reduced cross-sectional area of the positive tab 58 in the frangible region 84 can help concentrate the rupture of the positive tab 58.

[0055] Notably, the tab film 80 covers the frangible region 84 of the positive tab 58. Covering the frangible region 84 with the tab film 80, for example, can protect the frangible region 84 from an electrical arc in another region of the battery pack 18. Covering the frangible region 84 can help prevent an accidental rupture of the frangible region 84. In this example, the tab film 80 completely covers the frangible region 84.

[0056] In this example, the positive tab 58 has a frangible region 84. In another example, the negative tab 62 includes a frangible region 84. In one example, both the positive tab 58 and the negative tab 62 include a frangible region 84.

[0057] Referring to Figure 8A and Figure 8B Another example frangible region 84A of the tab 58A includes five circular holes.

[0058] Referring to Fig. as Figure 9A andFigure 9B Another example frangible region 84B of tab 58B includes three holes, two of which are slots that open to the sides of tab 58B.

[0059] Reference is made to Figure 10A and Figure 10B Another example frangible region 84C of tab 58C includes three holes having a diamond-shaped profile.

[0060] The foregoing description is exemplary in nature and is intended to be read in the ordinary sense, rather than to be construed as limiting on the present disclosure. Changes and modifications to the disclosed example can become apparent to those skilled in the art which do not necessarily depart from the essence of the present disclosure. Accordingly, the scope of protection is not limited to the described example, but is only defined by the claims that follow the description.

Claims

1. A battery assembly comprising: a housing that houses an electrode structure of a battery; a tab that electrically couples the electrode structure to a device external to the housing, the tab extending from an interior of the housing to an exterior of the housing, the tab including a frangible region; and a tab film that covers at least the frangible region of the tab.

2. The battery assembly of claim 1, wherein the frangible region includes a plurality of holes extending through a thickness of the tab, and optionally, wherein each hole of the plurality of holes has a diamond-shaped profile.

3. The battery assembly of claim 1, wherein the electrode structure is sealed within the housing.

4. The battery assembly of claim 1, wherein the frangible region provides a fuse.

5. The battery assembly of claim 1, wherein the tab film is polypropylene.

6. The battery assembly of claim 1, wherein the frangible region is sandwiched by the tab film, and optionally, wherein the frangible region is completely covered by the tab film.

7. The battery assembly of claim 1, wherein the device external to the housing is a busbar of a traction battery pack.

8. The battery assembly of claim 1, wherein the frangible region includes an array of holes extending through the tab, and optionally, wherein the frangible region includes at least one slot leading to a side of the tab.

9. The battery assembly of claim 1, wherein the frangible region is configured to rupture to interrupt a flow of current through the tab, and optionally, wherein the frangible region is configured to rupture in response to a current above a threshold current.

10. The battery assembly of claim 1, wherein the tab is a positive tab.

11. The battery assembly of claim 1, wherein the battery is a soft-pack battery.

12. A battery circuit interruption method comprising: directing a flow of current through a tab of a battery, the tab connecting an electrode of the battery located within a housing of the battery to an electrical component external to the housing; and covering a frangible region of the tab with a tab film, the frangible region configured to rupture to interrupt the flow of current through the tab in response to an overcurrent condition.

13. The battery circuit interruption method of claim 12, wherein the frangible region is completely covered by the tab film.

14. The battery circuit interruption method of claim 12, wherein the battery is a soft-pack battery.

15. The battery circuit interruption method of claim 12, wherein the frangible region includes a region of the tab having a plurality of holes, and optionally, wherein the plurality of holes each extend through a thickness of the tab. ​

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