Electrical sealant for battery cells and method of electrical sealing

Abstract

The present disclosure provides "Electrical Sealants and Methods for Electrical Sealing of Battery Cells". A battery cell assembly includes: an electrode structure; a housing that houses the electrode structure; and a wet-coat electrical sealant that covers at least a portion of at least one edge of the housing. A battery cell electrical sealing method includes: applying a liquid to at least one edge of a battery cell; and solidifying the liquid on the at least one edge to electrically seal the at least one edge.

Description

Technical Field

[0001] This disclosure generally relates to an electrical sealant for a battery cell, and more specifically to an electrical sealant that is applied as a liquid and cured to cover at least a portion of the edge of a battery cell housing. Background Technology

[0002] Electrified vehicles include a traction battery pack for powering the vehicle's motor and other electrical loads. The traction battery pack may include multiple battery cells and various other internal battery components that support the propulsion of the electrified vehicle. For example, a battery cell may include tab terminals secured to a busbar. During assembly, the tab terminals may be bent or otherwise manipulated to position them for attachment. Some known battery cells include tape along the edges of the battery cell. Summary of the Invention

[0003] In some respects, the technology described herein relates to a battery cell assembly comprising: an electrode structure; a housing that accommodates the electrode structure; and a wet-applied electrical sealant that covers at least a portion of at least one edge of the housing.

[0004] In some respects, the technology described herein relates to a battery cell assembly in which a wet-applied electrical sealant is cured to bond to the at least one edge.

[0005] In some respects, the technology described herein relates to a battery cell assembly in which the wet-applied electrical sealant has a cured state in which the wet-applied electrical sealant is bonded to the at least one edge.

[0006] In some respects, the technology described herein relates to a battery cell assembly that further includes tab terminals extending from the electrode structure within the housing to a region outside the housing, the tab terminals being close to the at least one edge.

[0007] In some respects, the technology described herein relates to a battery cell assembly in which a wet-applied electrical sealant contacts the tab terminals.

[0008] In some respects, the technology described herein relates to a battery cell assembly, wherein the wet-applied electrical sealant is a curable sealant.

[0009] In some respects, the technology described herein relates to a battery cell assembly in which the wet-applied electrical sealant is configured to cure to form a barrier over at least a portion of the at least one edge.

[0010] In some respects, the technology described herein relates to a battery cell assembly, wherein the housing includes an aluminum layer sandwiched between a first polymer base layer and a second polymer base layer.

[0011] In some respects, the technology described herein relates to a battery cell assembly, wherein the at least one edge includes at least one cut edge.

[0012] In some respects, the technology described herein relates to a battery cell assembly, wherein the electrode structure and the housing are components of a pouch cell.

[0013] In some respects, the technology described herein relates to a battery cell assembly, wherein the at least one edge is at least one cut edge.

[0014] In some respects, the technology described herein relates to a method for electrically sealing a battery cell, comprising: applying a liquid to at least one edge of the battery cell; and curing the liquid on the at least one edge to seal the at least one edge.

[0015] In some respects, the technology described herein relates to a method for electrically sealing a battery cell, wherein the at least one edge includes at least one cut edge of the housing of the battery cell.

[0016] In some respects, the technology described herein relates to a method for electrically sealing a battery cell, wherein the battery cell includes at least one tab terminal that extends from an electrode structure within the housing through at least one edge.

[0017] In some respects, the technology described herein relates to a method for electrically sealing a battery cell, which further includes bending the at least one tab terminal after the curing process.

[0018] In some respects, the technology described herein relates to a method for electrically sealing a battery cell, which further includes bending the at least one tab terminal by stamping it.

[0019] In some respects, the technology described herein relates to a method for electrically sealing a battery cell, wherein the coating comprises brushing the liquid onto the at least one edge.

[0020] In some respects, the technology described herein relates to a method for electrically sealing a battery cell, which further includes cutting the housing of the battery cell to create the at least one edge prior to the coating.

[0021] In some respects, the technology described herein relates to a method for electrically sealing a battery cell, wherein the battery cell is a pouch cell.

[0022] In some respects, the technology described herein relates to a method for electrically sealing a battery cell, wherein the liquid is a liquid electrical insulating tape.

[0023] Embodiments, examples, and alternatives, including any of their various aspects or respective individual features, may be adopted independently or in any combination of the foregoing paragraphs, claims, or the following description and drawings. Features described in connection with one embodiment are applicable to all embodiments unless such features are incompatible. Attached Figure Description

[0024] According to the specific embodiments, various features and advantages of the disclosed examples will become apparent to those skilled in the art. The accompanying drawings of the specific embodiments can be briefly described as follows:

[0025] Figure 1 A side view of an electrified vehicle with a battery pack is shown.

[0026] Figure 2 Showing from Figure 1 A perspective view of the battery array in the battery pack.

[0027] Figure 3 It shows Figure 2 An expanded view of the battery array.

[0028] Figure 4 An exemplary aspect of this disclosure is shown located within a terminal bending fixture. Figure 3 The battery cell, wherein a wet-applied electrical sealant covers at least one edge of the housing.

[0029] Figure 5 This shows what happens after bending one of the electrode terminals. Figure 4 The area.

[0030] Figure 6 This shows the material cut from sheet material. Figure 3 The housing of the battery cells in the array.

[0031] Figure 7 The housing after it has been formed to house the electrode structure is shown.

[0032] Figure 8 It shows Figure 7 The housing is folded onto the electrode structure and the tab terminals extend through the side of the housing.

[0033] Figure 9 It shows Figure 8 A close-up view of a region of the battery cell, showing the location of one of the tab terminals extending through the side of the battery cell.

[0034] Figure 10 This illustrates when electrical sealant is applied to at least one edge of the housing. Figure 9 The area. Detailed Implementation

[0035] Battery cells may include tabs extending from the housing. Some battery cells have their tabs bent before being installed in the battery array. Bending the tabs facilitates attachment of the tabs to busbars or other components within the traction battery pack.

[0036] This disclosure relates to an electrical sealant applied to at least a portion of the edge of a housing before bending the tab terminals. The electrical sealant may in particular interfere with the conductive path between the regions of the battery cell clamp used for bending the tab terminals.

[0037] refer to Figure 1 The electrified vehicle 10 includes a traction battery pack 14, a motor 16, and wheels 18. The traction battery pack 14 supplies power to the motor 16, which converts electrical energy into mechanical power to drive the wheels 18. The traction battery pack 14 may be a relatively high-voltage battery.

[0038] In an exemplary embodiment, the traction battery pack 14 is secured to the bottom 20 of the electric vehicle 10. In other examples, the traction battery pack 14 may be located elsewhere on the electric vehicle 10. In an exemplary embodiment, the traction battery pack 14 includes one or more battery arrays 22 housed within a pack housing 24.

[0039] Electrified vehicle 10 is a purely electric vehicle. In other examples, electrified vehicle 10 is a hybrid electric vehicle that selectively uses torque from an internal combustion engine (as a replacement or supplement to the electric motor) to drive the wheels. Generally, electrified vehicle 10 can be any type of vehicle with a traction battery pack.

[0040] Figure 2 and Figure 3 Additional details of one of the arrays 22 from the traction battery pack 14 are shown. In this example, array 22 includes an array housing assembly 30 with a housing structure (here, a cover 34 and a tray 38). In this example, the cover 34 is vertically above the tray 38. However, in other examples, the cover 34 may be positioned below or to the side of the tray 38.

[0041] Various terms such as “vertical,” “above,” “below,” “top,” and “bottom” are used in the various figures to describe the arrangement of components of the battery array 22 and should not be considered limiting in any other way. These terms are for illustrative purposes only when the battery array is installed... Figure 1 The overall orientation of the battery array 22 within the vehicle 10.

[0042] In one example of this disclosure, the cover 34 is welded to the tray 38. While welding is mentioned, the cover 34 and tray 38 may be joined using other fluid-tight joining techniques, such as adhesives. Furthermore, although an exemplary array housing assembly 30 is shown in the figures, the size, shape, and configuration of the array housing assembly 30 may vary within the scope of this disclosure.

[0043] In this disclosure, a cell stack 42 is arranged within a housing assembly 30. An exemplary cell stack 42 includes a plurality of individual battery cells 46 disposed along a cell stack axis A. The battery cells 46 may be compressed between a pair of end plates 50 along the cell stack axis A.

[0044] The cell stack 42 may include any number of battery cells 46. The battery array 22 may be expanded to include multiple cell stacks 42 within the housing assembly 30. Therefore, this disclosure is not limited to... Figure 2 The exact configuration shown.

[0045] In an exemplary embodiment, battery cell 46 is a pouch-type lithium-ion cell. However, within the scope of this disclosure, battery cells having other geometries (cylindrical, prismatic, etc.), other chemical substances (nickel-metal hydride, lead acid, etc.), or both may be used alternatively.

[0046] Busbar assembly 58 is positioned next to cell stack 42. Busbar assembly 58 includes frame 62 and multiple busbars 66 mounted to frame 62.

[0047] Each battery cell 46 includes a pair of tab terminals 54, which extend laterally outward from opposite sides of each of the battery cells 46. The tab terminals 54 may extend through holes 70 within the busbar 66 and frame 62. The tab terminals 54 may be folded onto the busbar 66 and directly secured to the busbar 68 to electrically connect the battery cells 46 to each other, to other components, etc. The tab terminals 54 may be directly secured to the busbar 68 via one or more solders.

[0048] In an exemplary embodiment, the tab terminal 54 is bent before being attached to the busbar 66. Bending the tab terminal 54 facilitates its attachment to the busbar 66. In some examples, the tab terminal 54 may alternatively or additionally be trimmed before installation and attachment to the busbar 66.

[0049] Now for reference Figure 4 and Figure 5 And continue to refer to Figure 3 During assembly, each of the battery cells 46 is positioned within a bending tool 74, which is actuated to bend the tab terminals 54 to a position suitable for mounting into the battery array 22.

[0050] In an exemplary embodiment, the bending tool 74 includes a lower tool 78 and an upper tool 82, the lower tool and the upper tool having a bending flange 86 associated with each of the tab terminals 54.

[0051] To bend one of the tab terminals 54 of the battery cell 46, the battery cell 46 is loaded into the lower tool 78 or bracket. The upper tool 82 is then pressed down, thereby driving the bending flange 86 into the associated tab terminal of the tab terminal 54.

[0052] Then, the slider 90 of the bending tool 74 can move inward toward the bending flange 86 to fold the tab terminal 54 onto the bending flange 86, as shown. Figure 5 As shown. The upper tool 82 can then be withdrawn, and the battery cell 46 can be removed from the lower tool 78 for installation into the battery array 22, wherein the tab terminals 54 of the battery cell 46 are bent to a position suitable for attachment to the busbar 66. The bending tool 74 may include areas electrically isolated from each other. For example, different portions of the lower tool 78 may be electrically isolated from each other.

[0053] In an exemplary embodiment, the battery cell 46 includes an electrical sealant 94 that helps to prevent the formation of a conductive path between the terminal 54 and other areas of the battery cell 46 during bending of the terminal 54.

[0054] Now for reference Figures 6 to 10 And continue to refer to Figures 3 to 5 The battery cell 46 includes a housing 100, which folds over and seals the electrode structure 104 when the battery cell 46 is assembled. The housing 100 is formed of a sheet of material 108, which is cut from a larger sheet of material, such as... Figure 6 As shown. The cut edge 112 surrounds the periphery of the housing 100.

[0055] The tab terminal 54 extends outward from inside the housing 100 to the area outside the housing 100. When the housing 100 is formed in a clamshell shape and then folded onto the electrode structure 104, as... Figure 7 and Figure 8 As shown, the tab terminal 54 extends from inside the housing 100 between the cut edges 112 of the housing 100.

[0056] The housing 100 may include an aluminum layer sandwiched between two polymer base layers. The aluminum layer may be exposed at the cut edge 112 after being cut from the material sheet 108. The aluminum layer may be incorporated into the housing 100 as a water vapor barrier.

[0057] An insulating sleeve 116 may surround the tab terminal 54 at the position where the tab terminal 54 exits from the housing 100. The insulating sleeve 116 prevents the tab terminal 54 from contacting the housing 100.

[0058] After folding the housing 100 and sealing the electrode structure 104 within the housing 100, the exemplary battery cell 46 has an electrical sealant 94 coated onto at least the area near the terminals 54 at the edge 112, such as Figure 10 As shown.

[0059] The exemplary electrical sealant 94 is a wet-applied electrical sealant. The exemplary electrical sealant 94 is applied as a liquid and then cured to bond to the cut edges 112 and other structures of the housing 100. Therefore, the electrical sealant 94 can be characterized as a curable sealant. In some examples, the electrical sealant 94 is a liquid electrical insulating tape. The wet application of the electrical sealant 94 to the structure distinguishes it from other types of barriers, such as adhesively fixed tapes.

[0060] The operator can use brush 120 to apply electrical sealant 94. Electrical sealant 94 can cover all cut edges 112 or only portions of cut edges 112, such as those near the tab terminals 54.

[0061] After applying the wet-applied electrical sealant 94, as the electrical sealant 94 cures, it hardens and bonds to the cut edge 112. After curing, the electrical sealant 94 can be considered to be in a cured state, in which the electrical sealant 94 is bonded to the edge 112.

[0062] In addition to the portion of the cut edge 112, in some examples, the electrical sealant 94 also covers the areas of the insulating sleeve 116 and the tab terminals 54. After curing, the electrical sealant 94 forms a barrier between at least some of the cut edges 112 of the housing 100 and other structures.

[0063] When the bending tool 74 is used to bend the tab terminal 54, the electrical sealant 94 prevents the bending flange 86 from forming a conductive path between the tab terminal 54 and the battery cell 46 or other areas of the bending tool 74 (such as between the tab terminal 54 and the aluminum layer of the housing 100).

[0064] The disclosed examples feature the application of a curable electrical sealant to the cut edges of the battery cell casing. The sealant covers the cut edges. The application of the curable electrical sealant can be automated in a relatively simple manner.

[0065] The foregoing description is exemplary in nature and not restrictive. Variations and modifications made to the disclosed examples will become apparent to those skilled in the art, and such variations and modifications do not necessarily depart from the spirit of this disclosure. Therefore, the scope of protection accorded to this disclosure can only be determined by examining the appended claims.

Claims

1. A battery cell assembly, comprising: Electrode structure; A housing that accommodates the electrode structure; as well as A wet-applied electrical sealant that covers at least a portion of at least one edge of the housing.

2. The battery cell assembly of claim 1, wherein the wet-applied electrical sealant is cured to bond to the at least one edge.

3. The battery cell assembly according to claim 1, wherein the wet-applied electrical sealant has a cured state, and in the cured state, the wet-applied electrical sealant is bonded to the at least one edge.

4. The battery cell assembly of claim 1, further comprising tab terminals extending from the electrode structure within the housing to a region outside the housing, the tab terminals being adjacent to the at least one edge, and optionally, wherein the wet-applied electrical sealant contacts the tab terminals.

5. The battery cell assembly according to claim 1, wherein the wet-applied electrical sealant is a curable sealant.

6. The battery cell assembly of claim 1, wherein the wet-applied electrical sealant is configured to cure to form a barrier over at least a portion of the at least one edge.

7. The battery cell assembly according to claim 1, wherein the housing includes an aluminum layer sandwiched between a first polymer base layer and a second polymer base layer.

8. The battery cell assembly according to claim 1, wherein the at least one edge includes at least one cut edge.

9. The battery cell assembly according to claim 1, wherein the electrode structure and the housing are components of a pouch cell.

10. The battery cell assembly according to claim 1, wherein the at least one edge is at least one cut edge.

11. A method for providing an electrical sealant for a battery cell, comprising: Apply the liquid to at least one edge of the battery cell; as well as The liquid on the at least one edge is cured to provide an electrical sealant at the at least one edge.

12. The method of providing an electrical sealant for a battery cell according to claim 11, wherein the at least one edge includes at least one cut edge of the housing of the battery cell, and optionally, wherein the battery cell includes at least one tab terminal extending from an electrode structure within the housing through the at least one edge.

13. The method of providing electrical sealant for a battery cell according to claim 12, further comprising bending the at least one tab terminal after curing, and optionally, the method further comprising bending the at least one tab terminal by stamping the at least one tab terminal.

14. The method of providing an electrical sealant for a battery cell according to claim 11, further comprising cutting the housing of the battery cell to provide the at least one edge prior to the coating, and optionally, wherein the coating comprises brushing the liquid onto the at least one edge.

15. The method for providing electrical sealant for battery cells according to claim 11, wherein the liquid is a liquid electrical insulating tape.

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