Air ventilation and exhaust hole for encapsulating battery pack

Abstract

A battery module includes a housing including a sidewall structure, a top shear plate, and a bottom shear plate. The vent tray assembly is disposed within the housing and includes a plurality of battery cell trays and a plurality of vent trays that combine to define a plurality of vent passages therebetween. The battery cell tray includes a substrate having a plurality of vent openings in communication with one of the plurality of vent channels, and the vent tray assembly includes an air vent covered with a semi-permeable medium. The plurality of battery cells each include an end portion having a vent hole aligned with one of the vent openings in the substrate in the battery cell tray. The potting foam material is dispersed within the housing and between the cells.

Description

Technical Field

[0001] The present disclosure relates to a method of filling a battery pack with an expanding foam potting material by exhausting air outside a potting area. Background Art

[0002] The information provided in this section is for the purpose of generally introducing the background of the present disclosure. To the extent described in this section, the work of the currently named inventors, as well as aspects that may not otherwise constitute prior art at the time of filing and may not be described, are neither expressly nor implicitly admitted to be prior art against the present disclosure.

[0003] Cylindrical battery packs typically require potting material to be encapsulated around the battery cells to provide structural support and protection against thermal runaway propagation. Automotive battery packs employ an exhaust system that allows individual battery cells to exhaust through a channel system that isolates the channels from the rest of the battery pack. During a thermal event, the exhaust system must remain open for gases to pass through in order to allow the gases to reach the exhaust port of the battery pack. Therefore, during the potting process, it is necessary to prevent the potting material from entering the exhaust system.

[0004] Although foam potting materials are used in several automotive battery packs on the market, voids are common. Voids may be created due to underfilling or residual air. The presence of voids may have an adverse effect on thermal runaway performance by allowing combustion gases to migrate between battery cells or in high-pressure areas, and may reduce structural performance due to reduced material and non-uniform distribution. Foam potting materials typically consist of polyurethane, but may also be epoxy resin, silicone, or other resins. The potting material is dispensed in liquid resin form and then expands due to a chemical reaction. After a period of time, the material fully expands and hardens to form a foamed plastic material. During the expansion process, the foam material releases air, which must be removed from the battery pack to avoid voids in the potting material. However, there is a risk that the air exhaust ports will allow the foam resin to pass through, which may cause blockage of the exhaust areas, which must be left un-potted. Summary of the Invention

[0005] In accordance with the principles of the present disclosure, potting material is dispensed around and inside the battery module. Air is pushed through strategically located exhaust channels formed by overlapping joints in an exhaust tray assembly.

[0006] According to one aspect of the present disclosure, a battery module includes a housing that includes a sidewall structure, a top shear plate, and a bottom shear plate. An exhaust tray assembly is disposed within the housing and includes a plurality of cell trays and a plurality of exhaust trays, and the plurality of cell trays and the plurality of exhaust trays are combined to define a plurality of exhaust channels therebetween. The cell tray includes a substrate having a plurality of exhaust openings that communicate with one of the plurality of exhaust channels, and the exhaust tray assembly includes air exhaust holes covered with a semi-permeable medium. Each of the plurality of cells includes an end portion having a vent hole that is aligned with one of the exhaust openings in the substrate of the cell tray. A potting foam material is dispersed within the housing and between the cells.

[0007] According to another aspect, the cell tray includes a plurality of parallel ribs extending from the substrate of the cell tray, and the exhaust tray includes a substrate and a plurality of parallel ribs extending from the substrate of the exhaust tray, and the plurality of parallel ribs of the cell tray and the plurality of parallel ribs of the exhaust tray are combined to form a plurality of exhaust channels.

[0008] According to another aspect, the cells are one of cylindrical and square types.

[0009] According to another aspect, the air exhaust holes include a plurality of air exhaust holes located in a central region of the cell housing.

[0010] According to another aspect, the exhaust tray includes a substrate and a plurality of pairs of parallel ribs that are aligned with a respective one of the plurality of parallel ribs of the cell tray to define a plurality of exhaust channels.

[0011] According to another aspect, the air exhaust holes extend through a riveted hollow protrusion extending from the substrate of the cell tray.

[0012] According to another aspect, the riveted hollow protrusion extends through an opening in a mica layer disposed against the substrate of the cell tray.

[0013] According to another aspect, the air exhaust holes include tapered openings.

[0014] According to another aspect, the air exhaust holes include an insert received in an opening in the cell tray, and the insert includes an opening therethrough.

[0015] According to another aspect, the semi-permeable medium includes one of open-cell foam material, felt, woven fabric, knitted fabric, non-woven fabric, and paper.

[0016] According to another aspect, a method of manufacturing a battery module includes inserting a plurality of battery cells into an inverted housing having a top shear plate and a sidewall structure. An exhaust tray assembly is placed on top of the batteries. The exhaust tray assembly includes a plurality of battery cell trays and a plurality of exhaust trays. The plurality of battery cell trays and the plurality of exhaust trays are combined to define a plurality of exhaust channels therebetween. Each battery cell tray includes a substrate having a plurality of exhaust openings in communication with one of the plurality of exhaust channels. The battery cell tray includes an air exhaust hole covered with a semi-permeable medium. A potting foam material is dispensed into the housing in a pattern such that the potting foam material reaches the air exhaust holes after substantially all of the air within the housing has passed through the air exhaust holes.

[0017] The present invention provides the following technical solutions:

[0018] 1. A battery module, comprising:

[0019] A housing, the housing including a sidewall structure, a top shear plate, and a bottom shear plate;

[0020] An exhaust tray assembly, the exhaust tray assembly disposed within the housing and including a plurality of battery cell trays and a plurality of exhaust trays. The plurality of battery cell trays and the plurality of exhaust trays are combined to define a plurality of exhaust channels therebetween. The battery cell tray includes a substrate having a plurality of exhaust openings in communication with one of the plurality of exhaust channels. The exhaust tray assembly includes an air exhaust hole covered with a semi-permeable medium;

[0021] A plurality of battery cells, each battery cell having an end with a vent hole that is aligned with one of the exhaust openings in the substrate of the battery cell tray; and

[0022] Potting foam material dispersed within the housing and between the batteries.

[0023] 2. The battery module according to solution 1, wherein the battery cell tray includes a plurality of parallel ribs extending from the substrate of the battery cell tray, and the exhaust tray includes a substrate and a plurality of parallel ribs extending from the substrate of the exhaust tray. The plurality of parallel ribs of the battery cell tray and the plurality of parallel ribs of the exhaust tray are combined to form a plurality of exhaust channels.

[0024] 3. The battery module according to solution 1, wherein the battery cells are one of cylindrical and square types.

[0025] 4. The battery module according to solution 1, wherein the air exhaust holes include a plurality of air exhaust holes located in a central region of the battery housing.

[0026] 5. The battery module according to Scheme 1, wherein the exhaust tray includes a substrate and multiple pairs of parallel ribs, and the multiple pairs of parallel ribs are aligned with a corresponding one of the multiple parallel ribs of the battery cell tray to define the multiple exhaust channels.

[0027] 6. The battery module according to Scheme 1, wherein the air exhaust hole extends through a riveted hollow protrusion extending from the substrate of the battery cell tray.

[0028] 7. The battery module according to Scheme 1, wherein the riveted hollow protrusion extends through an opening in a mica layer provided against the substrate of the battery cell tray.

[0029] 8. The battery module according to Scheme 1, wherein the air exhaust hole includes a tapered opening.

[0030] 9. The battery module according to Scheme 1, wherein the air exhaust hole includes an insert received in an opening in the battery cell tray, and the insert includes an opening therethrough.

[0031] 10. The battery module according to Scheme 1, wherein the semi-permeable medium includes one of open-cell foam material, felt, woven fabric, knitted fabric, non-woven fabric, and paper.

[0032] 11. A method of fabricating a battery module, comprising:

[0033] Inserting a plurality of battery cells into an inverted housing having a top shear plate and a sidewall structure;

[0034] Placing an exhaust tray assembly on top of the batteries, the exhaust tray assembly including a plurality of battery cell trays and a plurality of exhaust trays, the plurality of battery cell trays and the plurality of exhaust trays being combined to define a plurality of exhaust channels therebetween, each battery cell tray including a substrate having a plurality of exhaust openings in communication with one of the plurality of exhaust channels, the battery cell tray including an air exhaust hole covered with a semi-permeable medium;

[0035] Dispersing a potting foam material into the housing in a pattern such that the potting foam material reaches the air exhaust hole after substantially all of the air in the housing has passed through the air exhaust hole.

[0036] 12. The method according to Scheme 11, wherein the battery cell tray includes a plurality of parallel ribs extending from the substrate of the battery cell tray, and the exhaust tray includes a substrate and a plurality of parallel ribs extending from the substrate of the exhaust tray, and the plurality of parallel ribs of the battery cell tray and the plurality of parallel ribs of the exhaust tray are combined to form a plurality of exhaust channels.

[0037] 13. The method according to aspect 11, wherein the potting foam material is dispensed around the perimeter of the housing.

[0038] 14. The method according to aspect 11, wherein the air vent hole is in a central region of the housing.

[0039] 15. The method according to aspect 11, wherein the battery cell is one of cylindrical and square types.

[0040] 16. The method according to aspect 11, wherein the air vent hole extends through a riveted hollow protrusion extending from the substrate of the battery cell tray.

[0041] 17. The method according to aspect 11, wherein the riveted hollow protrusion extends through an opening in a mica layer disposed against the substrate of the battery cell tray.

[0042] 18. The method according to aspect 11, wherein the air vent hole includes a tapered opening.

[0043] 19. The method according to aspect 11, wherein the air vent hole includes an insert received in an opening in the battery cell tray, and the insert includes an opening therethrough.

[0044] 20. The method according to aspect 11, wherein the semi-permeable medium includes one of open-cell foam material, felt, woven fabric, knitted fabric, non-woven fabric, and paper.

[0045] Other application areas of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and specific examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The present disclosure will be more fully understood from the detailed description and the drawings, in which:

[0047] Figure 1 is a cross-sectional view of a portion of a battery pack according to the principles of the present disclosure having an exhaust for a potting area;

[0048] Figures 2A - 2C illustrates a process for forming an air vent hole in an exhaust tray assembly according to the principles of the present disclosure;

[0049] Figures 3A - 3C illustrates a process for forming an air vent hole in an exhaust tray assembly according to a second embodiment;

[0050] Figure 4 is a cross-sectional view of an air vent hole in an exhaust tray assembly according to a third embodiment; and

[0051] Figure 5 FIG. 2 is a schematic view of a battery pack showing an example of a potting material dispensing location and an air vent location in accordance with the principles of the present disclosure.

[0052] In the drawings, reference numerals may be reused to identify like and / or identical elements. DETAILED DESCRIPTION

[0053] Reference Figure 1 , shows a partial cross-sectional view of the battery module 10 in an inverted state for receiving potting and including an upper shear plate 12 and an integrated circuit board 14. A plurality of battery cells 16 are disposed on top of the integrated circuit board 14. A plurality of cooling strips 18 may be disposed between rows of battery cells for cooling the battery cells 16. A battery cell tray 20 is disposed on top of the battery cells 16, and an exhaust tray 22 is engaged with the battery cell tray 20. When the battery module 10 is inverted as Figure 1 shown, a bottom shear plate 24 is located on top of the exhaust tray 22.

[0054] The battery cell tray 20 includes a substrate 26 having a plurality of exhaust openings 28, each exhaust opening 28 being aligned with one of the battery cells 16. A mica layer 30 is disposed above the exhaust openings 28. The battery cell tray 20 further includes a plurality of parallel ribs 32 extending from the substrate 26. The exhaust tray 22 includes a substrate 33 and a plurality of pairs of parallel ribs 34, each pair of parallel ribs 34 receiving one of the plurality of parallel ribs 32 of the battery cell tray 20 therebetween. The ribs 32 of the battery cell tray 20 and the ribs 34 of the exhaust tray 22 cooperate to define a plurality of parallel exhaust channels 36 that are aligned with the plurality of exhaust openings 28. The parallel exhaust channels 36 allow each individual battery cell 16 to exhaust through the mica layer 30 by rupturing the mica and the exhaust openings 28, while the exhaust channels 36 isolate the remaining battery cells 16 of the battery pack 10.

[0055] An air vent 40 is formed through the substrate 26 to allow air to escape from the housing when potting material 2 is dispensed into the housing. Specifically, the potting material may be dispensed in the form of a resin, and when it reacts with air, the resin expands into a foam material 2. The foam material displaces the air within the module 10, and the air is removed through the air vent 40. Reference Figures 2A - 2C , the air vent 40 may be formed by forming a hollow tubular protrusion 42 extending from the substrate 26 of the battery cell tray 20. The hollow tubular protrusion 42 includes a channel 44 therethrough. The hollow tubular protrusion extends through an opening in the mica 30, as Figure 2A shown. As Figure 2BAs shown, the hollow tubular protrusion 42 can be heat staked to hold the mica 30 in place. The staked protrusion 46 can be formed with a tapered seat 48 that receives a semi-permeable medium 50, such as open-cell foam material, felt, woven or knitted fabric, non-woven fabric, paper, or other selected membrane materials, such as Figure 2C shown.

[0056] Referring Figure 5 to[reference number not provided], a battery module 10 is schematically shown, in which potting material dispensing locations are shown at a plurality of locations 60 around the perimeter of the sidewall structure 62 and below the center of the housing 64. Additional dispensing locations 66 can be provided within the middle portion of the housing 64, as shown. When the potting material 2 is dispensed as a resin, it chemically changes to an expanded foam material that expels air from the housing 64. As the foam material expands, air is exhausted from the air vent 40 into the channel 36. As Figure 5 shown, the air vent 40 is located at a central position, and the potting material 2 dispensing locations 60, 66 are positioned to allow the potting foam material 2 to expand and expel substantially all of the air from the housing 64 before the potting foam material reaches the air vent 40. The semi-permeable medium 50 allows air to pass through but blocks the passage of the potting foam material injected into the battery module 10.

[0057] Referring Figures 3A - 3C to[reference number not provided], an alternative method of forming the air vent 140 is shown. As Figure 3A shown, an opening 142 is formed through the substrate 26 of the battery cell tray 20. The opening 142 can include a tapered surface 144 surrounding the opening 142. As Figure 3B shown, a liquid resin 146 is dispensed into the tapered surface 144 surrounding the opening 142. The viscosity and surface tension of the liquid resin 146 prevent the resin from dripping through the opening 142. As Figure 3C shown, the resin 146 foams and cures in place to form an open-cell foam material 148 that provides a selective valve that allows air to escape the housing during the dispersion of the potting material 2 into the exhaust channel 36 and prevents the potting material 2 from passing through.

[0058] Referring Figure 4, shows an alternative air vent hole 240 in the substrate 26 that extends through the battery cell tray 20. The air vent hole 240 is formed by an insert 242 that is received in an opening 244 in the substrate 26 of the battery cell tray 20. The insert 242 includes an opening 246 therethrough, and an open-cell foam material 248 or other semi-permeable medium is disposed in the opening 246. The insert 242 may include external threads 250 that may be received in the threaded opening 244 or may otherwise be fastened within the opening 244 by a press fit, heat staking, or an adhesive. The semi-permeable material within the air vent hole 240 allows air to pass through but blocks the passage of the potting foam material injected into the battery module 10.

[0059] The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Thus, while the disclosure includes specific examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon study of the drawings, the specification, and the appended claims. It should be understood that one or more steps within a method can be executed in a different order (or concurrently) without altering the principles of the disclosure. Additionally, although each embodiment above is described as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more of the embodiments with each other are still within the scope of the disclosure.

[0060] Various terms are used, including "connected", "engaged", "coupled", "adjacent", "next to", "on", "above", "below", and "disposed", to describe the spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.). Unless explicitly described as "direct", when describing the relationship between a first element and a second element in the foregoing disclosure, the relationship can be a direct relationship where no other intermediate elements exist between the first element and the second element, but can also be an indirect relationship where one or more intermediate elements (spatially or functionally) exist between the first element and the second element. As used herein, the phrase "at least one of A, B, and C" should be interpreted to mean a logical (A or B or C) using non-exclusive logic "or" and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C".

Claims

1. A battery module, comprising: a housing, the housing including a sidewall structure, a top shear plate, and a bottom shear plate; an exhaust tray assembly, the exhaust tray assembly disposed within the housing and including a plurality of cell trays and a plurality of exhaust trays, the plurality of cell trays and the plurality of exhaust trays combined to define a plurality of exhaust channels therebetween, the cell tray including a substrate having a plurality of exhaust openings in communication with one of the plurality of exhaust channels, the exhaust tray assembly including air exhaust holes covered with a semi-permeable medium; a plurality of battery cells, each battery cell having an end with a vent hole, the vent hole aligned with one of the exhaust openings in the substrate of the cell tray; and a potting foam material dispersed within the housing and between the batteries.

2. The battery module according to claim 1, wherein The cell tray includes a plurality of parallel ribs extending from the substrate of the cell tray, and the exhaust tray includes a substrate and a plurality of parallel ribs extending from the substrate of the exhaust tray, and the plurality of parallel ribs of the cell tray and the plurality of parallel ribs of the exhaust tray combine to form the plurality of exhaust channels.

3. The battery module according to claim 1, wherein, The battery cells are one of cylindrical and square types.

4. The battery module according to claim 1, wherein, The air exhaust holes include a plurality of air exhaust holes located in a central region of the battery housing.

5. The battery module according to claim 1, wherein the exhaust tray includes a substrate and a plurality of pairs of parallel ribs, the plurality of pairs of parallel ribs aligned with a corresponding one of the plurality of parallel ribs of the cell tray to define the plurality of exhaust channels.

6. The battery module according to claim 1, wherein The air exhaust holes extend through a riveted hollow protrusion extending from the substrate of the cell tray.

7. The battery module according to claim 1, wherein the riveted hollow protrusion extends through an opening in a mica layer disposed against the substrate of the cell tray.

8. The battery module according to claim 1, wherein, The air exhaust holes include tapered openings.

9. The battery module according to claim 1, wherein, The air exhaust holes include inserts received in openings in the cell tray, and the inserts include openings therethrough.

10. The battery module according to claim 1, wherein the semi-permeable medium includes one of open-cell foam material, felt, woven fabric, knitted fabric, non-woven fabric, and paper.

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