Method of filling battery pack with expanded foam fill using air vent established within thermal runaway propagation ventilation system

Abstract

A battery module includes a housing including a sidewall structure, a top shear plate, and a bottom shear plate. A vent tray assembly is disposed within the housing and includes a plurality of unit trays and a plurality of vent trays that combine to define a plurality of vent channels therebetween. The unit tray includes a base plate having a plurality of ventilation openings in communication with one of the plurality of ventilation channels, and the ventilation tray assembly includes an air vent through a seam between the base plates of the unit tray. The plurality of battery cells each include an end having a vent aligned with one of the vent openings in the base plate in the cell tray. Filling foam is dispersed within the housing and between the cells.

Description

Technical Field

[0001] The present disclosure relates to a method for filling a battery pack with an expandable foam filling body by venting air outside a filling area. Background Art

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

[0003] Cylindrical unit battery packs typically require a filling material to be encapsulated around the unit to provide structural support and protection against thermal runaway propagation. Automotive battery packs have used ventilation systems that allow individual battery cells to be ventilated through a passage system that isolates the passage from the rest of the battery pack. To allow gas to reach the ventilation ports of the pack, the ventilation system must remain open for the gas to pass through during a thermal event. Thus, during the filling process, it is necessary to prevent the filling body from entering the ventilation system.

[0004] Although foam filling bodies are used in a variety of automotive battery packs on the market, voids are a common occurrence. Voids can be created due to underfilling or entrained air. The presence of voids can adversely affect thermal runaway performance by allowing overheated gas to move between cells or in high voltage areas, and can reduce structural performance due to reduced material and uneven distribution. Foam filling bodies are typically composed of polyurethane, but can also be epoxy resin, silicone resin, or other resins. The filling body is dispensed as a liquid resin 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 expansion, the foam vents air, which must be removed from the battery pack to avoid voids in the filling material. However, the air ventilation ports risk allowing the foaming resin to pass through, which can result in blockage of the ventilation areas that must remain free of the filling body. Summary of the Invention

[0005] In accordance with the principles of the present disclosure, the filling body is dispensed around and within a battery module. Air is pushed towards strategically located ventilation passages that are formed through stacked joints in a ventilation tray assembly.

[0006] According to one aspect of the present disclosure, a battery module includes a housing, the housing including a sidewall structure, a top shear plate, and a bottom shear plate. A ventilation tray assembly is disposed within the housing and includes a plurality of unit trays and a plurality of ventilation trays, the plurality of unit trays and the plurality of ventilation trays being combined to define a plurality of ventilation channels therebetween. The unit tray includes a base plate having a plurality of ventilation openings that communicate with one of the plurality of ventilation channels, and the ventilation tray assembly includes an air vent that passes through a seam between the base plates of the unit trays. Each of the plurality of battery cells includes an end having a vent that aligns with one of the ventilation openings in the base plate of the unit tray. Filling foam is dispersed within the housing and between the batteries.

[0007] According to another aspect, the unit tray includes a plurality of parallel ribs extending from the base plate of the unit tray, and the ventilation tray includes a base plate and a plurality of parallel ribs extending from the base plate of the ventilation tray, and the plurality of parallel ribs of the unit tray and the plurality of parallel ribs of the ventilation tray are combined to form the plurality of ventilation channels.

[0008] According to another aspect, the air vent includes a plurality of air vents, each including a protruding protective cover extending from an edge of the base plate of the unit tray.

[0009] According to another aspect, a mica layer covers the base plate of the unit tray, and wherein the air vent is defined between the seam between the unit trays and the mica layer.

[0010] According to another aspect, a semi-permeable medium extends between rows of the plurality of battery cells and adjacent to the plurality of unit trays.

[0011] According to another aspect, the battery cells are of one of a cylindrical and a prismatic type.

[0012] According to another aspect, the air vent includes a plurality of air vents located in a central region of the battery housing.

[0013] According to another aspect, the width of the air vent in at least one direction is less than 1 millimeter.

[0014] According to another aspect, the ventilation tray includes a base plate and a plurality of pairs of parallel ribs, the plurality of pairs of parallel ribs being aligned with a corresponding one of the plurality of parallel ribs of the unit tray to define the plurality of ventilation channels.

[0015] According to another aspect, the air vent is formed by stacking stepped features along adjacent edges of the base plate of the unit tray.

[0016] According to another aspect, a method of fabricating a battery module includes: inserting a plurality of battery cells into an upside-down housing having a top shear plate and a sidewall structure. A ventilation tray assembly is placed on top of the batteries, the ventilation tray assembly including a plurality of unit trays and a plurality of ventilation trays, the plurality of unit trays and the plurality of ventilation trays being combined to define a plurality of ventilation channels therebetween, each unit tray including a base plate having a plurality of ventilation openings in communication with one of the plurality of ventilation channels, the unit tray including an air vent passing through a seam between the unit trays. Filling foam is dispensed into the housing in a pattern such that the filling foam reaches the air vent after substantially all of the air within the housing has passed through the air vent.

[0017] Solution 1. A battery module, comprising:

[0018] A housing including a sidewall structure, a top shear plate, and a bottom shear plate;

[0019] A ventilation tray assembly disposed within the housing and including a plurality of unit trays and a plurality of ventilation trays, the plurality of unit trays and the plurality of ventilation trays being combined to define a plurality of ventilation channels therebetween, the unit tray including a base plate having a plurality of ventilation openings in communication with one of the plurality of ventilation channels, the ventilation tray assembly including an air vent passing through one of a hole in the base plate and a seam between the base plates of the unit trays;

[0020] A plurality of battery cells, each having an end with a vent that is aligned with one of the ventilation openings in the base plate of the unit tray; and

[0021] Filling foam dispersed within the housing and between the batteries.

[0022] Solution 2. The battery module according to Solution 1, wherein the unit tray includes a plurality of parallel ribs extending from the base plate of the unit tray, and the ventilation tray includes a base plate and a plurality of parallel ribs extending from the base plate of the ventilation tray, and the plurality of parallel ribs of the unit tray and the plurality of parallel ribs of the ventilation tray are combined to form the plurality of ventilation channels.

[0023] Solution 3. The battery module according to Solution 1, wherein the air vent includes a plurality of air vents, each including a protruding protective cover extending from an edge of the base plate of the unit tray.

[0024] Solution 4. The battery module according to Solution 1, further including a mica layer covering the base plate of the unit tray, and wherein the air vent is defined between a seam between the unit trays and the mica layer.

[0025] Solution 5. The battery module according to Solution 1 further includes a semi-permeable medium extending between rows of the plurality of battery cells and adjacent to the plurality of unit trays.

[0026] Solution 6. The battery module according to Solution 1, wherein the battery cells are one of cylindrical and prismatic types.

[0027] Solution 7. The battery module according to Solution 1, wherein the air vents include a plurality of air vents located in a central region of the battery housing.

[0028] Solution 8. The battery module according to Solution 1, wherein the width of the air vents in at least one direction is less than 1 mm.

[0029] Solution 9. The battery module according to Solution 1, wherein the ventilation tray includes a base plate and a plurality of pairs of parallel ribs, and the plurality of pairs of parallel ribs are aligned with a corresponding one of the plurality of parallel ribs of the unit tray to define the plurality of ventilation channels.

[0030] Solution 10. The battery module according to Solution 1, wherein the air vents are formed by stacking stepped features along adjacent edges of the base plate of the unit tray.

[0031] Solution 11. A method of manufacturing a battery module, comprising:

[0032] Inserting a plurality of battery cells into an upside-down housing having a top shear plate and a sidewall structure;

[0033] Placing a ventilation tray assembly on top of the battery, the ventilation tray assembly including a plurality of unit trays and a plurality of ventilation trays, the plurality of unit trays and the plurality of ventilation trays being combined to define a plurality of ventilation channels therebetween, each unit tray including a base plate having a plurality of ventilation openings communicating with one of the plurality of ventilation channels, and the unit tray including an air vent passing through one of the holes in the base plate and the seams between the unit trays;

[0034] Dispensing a filling foam into the housing in a pattern such that the filling foam reaches the air vents after substantially all of the air in the housing has passed through the air vents.

[0035] Solution 12. The method according to Solution 11, wherein the unit tray includes a plurality of parallel ribs extending from the base plate of the unit tray, and the ventilation tray includes a base plate and a plurality of parallel ribs extending from the base plate of the ventilation tray, and the plurality of parallel ribs of the unit tray and the plurality of parallel ribs of the ventilation tray are combined to form a plurality of ventilation channels.

[0036] Solution 13. The method according to Solution 11, wherein the filling foam is dispensed around the perimeter of the housing.

[0037] Solution 14. The method according to Solution 11, wherein the air vent includes a plurality of air vents, each including a protruding protective cover extending from an edge of the base plate of the unit tray.

[0038] Solution 15. The method according to Solution 11, wherein the air vent is located in a central region of the battery housing.

[0039] Solution 16. The method according to Solution 11, wherein the width of the air vent in at least one direction is less than 1 mm.

[0040] Solution 17. The method according to Solution 11, wherein the air vent is formed by stacking stepped features along adjacent edges of the base plate of the unit tray.

[0041] Solution 18. The method according to Solution 11, wherein the battery cell is one of a cylindrical and a prismatic type.

[0042] Solution 19. The method according to Solution 11, further comprising placing a semi-permeable medium between rows of the battery cells.

[0043] Solution 20. The method according to Solution 11, further comprising placing a mica layer over the plurality of base plates of the unit tray.

[0044] Other application areas of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and the specific examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The present disclosure will be more fully understood from the detailed description and the drawings, wherein:

[0046] Figure 1 is a cross-sectional view of a portion of a battery pack having ventilation for a filling area according to the principles of the present disclosure;

[0047] Figure 2 is a cross-sectional view of a gas ventilation tray system according to the principles of the present disclosure, wherein air vents through seams in the gas ventilation tray for a filling area;

[0048] Figure 3 is a cross-sectional view of an air ventilation system in a seam of a gas ventilation tray according to the principles of the present disclosure;

[0049] Figure 4 is a schematic view of a battery pack illustrating an example of a filling body dispensing position according to the principles of the present disclosure;

[0050] Figure 5 is a cross-sectional view of the battery pack showing an example of a filling body dispensing position according to the principles of the present disclosure;

[0051] Figure 6 Perspective view of a part of a unit tray of a gas ventilation tray system;

[0052] Figure 7 Perspective view of a part of a unit tray of a gas ventilation tray system covered with mica;

[0053] Figure 8 Partial cross-sectional view of a part of a battery module, showing open-cell foam placed between battery cells;

[0054] Figure 9 Perspective view of open-cell foam placed between battery cells;

[0055] Figure 10 Top perspective view of a ventilation passage along a seam of the unit tray;

[0056] Figure 11 Bottom perspective view of a ventilation passage along a seam of the unit tray; and

[0057] Figure 12 Bottom plan view of a unit tray assembly, showing the ventilation passage positioned along its seam.

[0058] In the drawings, reference numerals may be reused to identify similar and / or identical elements. Detailed Description

[0059] Referring to Figure 1 , a partial cross-sectional view of the battery module 10 is shown in an upside-down state for receiving a filling body and includes 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 bands 18 may be disposed between rows of the battery cells for cooling the battery cells 16. A unit tray 20 is disposed on top of the battery cells 16 and a ventilation tray 22 is engaged with the unit tray 20. When the battery module 10 is upside down as shown in Figure 1 , a bottom shear plate 24 is on top of the ventilation tray 22.

[0060] The unit tray 20 includes a base plate 26 having a plurality of ventilation openings 28, each of the ventilation openings 28 being aligned with one of the battery cells 16. A mica 30 layer is disposed over the ventilation openings 28. The unit tray 20 further includes a plurality of parallel ribs 32 extending from the base plate 26. The ventilation tray 22 includes a base plate 33 and a plurality of pairs of parallel ribs 34, each pair of the plurality of pairs of parallel ribs 34 receiving one of the plurality of parallel ribs 32 of the unit tray 20 therebetween. The ribs 32 of the unit tray 20 and the ribs 34 of the ventilation tray 22 cooperate to define a plurality of parallel ventilation channels 36 that are aligned with the plurality of ventilation openings 28. The parallel ventilation channels 36 allow each battery cell 16 to ventilate through the mica 30 layer and the ventilation openings 28, while the ventilation channels 36 isolate the remaining battery cells 16 of the battery pack 10.

[0061] Referring to Figure 2 , a seam 38 is provided between adjacent base plates 26 of the unit tray 20. An air vent 40 is provided through the seam 38 to allow air to escape from the housing when the filling body 2 is dispensed into the housing. Specifically, the filling body may be dispensed as a resin and then react to expand into a foam 2. The foam removes air from the module 10 and the air is removed through the air vent 40. The air vent 40 may be formed by stacking stepped features 42, 44 along adjacent edges of the base plate 26 of the unit tray 20. A gap of less than 1 mm may be provided between the stacked stepped features 42, 44. One stepped feature 42 includes a recessed area located on the bottom surface of the base plate 26 and the other stepped feature 44 includes a recessed area located on the top surface of the base plate 26. Alternatively, holes 45 (see Figure 8 ) may be provided in the base plate to allow air ventilation.

[0062] Referring to Figure 3 , a projecting shield 46 may extend downwardly from the edge of the base plate 26 of one of the unit trays 20 to cover the air vent 40 or other holes 45 passing through the seam 38. The projecting shield 46 and the stacked stepped features 42, 44 together define a curved path for air to ventilate from the battery module 10.

[0063] Referring to Figure 4 and 5, schematically shows a battery module 10, where the dispensing positions of the filling body are illustrated at multiple positions 50 around the perimeter of the sidewall structure 51 and down a center of the housing 52. Additional dispensing positions 54 may be provided within the middle portion of the housing 52, as shown. As the filling body 2 is dispensed as resin, it interacts with air and chemically changes into an expanding foam that removes air from the housing 52. As the foam expands, air is discharged from the air vents 40 in the seam 38. The air vents 40 are located at central positions, and the dispensing positions 50, 54 of the filling body 2 are positioned to allow the filling foam to expand and discharge substantially all of the air from the housing 52 before the filling foam reaches the air vents 40, 45.

[0064] Reference Figure 6 and 7 , shows a perspective view of a portion of a unit tray 20 of a gas ventilation tray system, including a plurality of parallel ribs 32 between multiple rows of ventilation openings 28 provided in a base plate 26 of the unit tray 20. Figure 7 is a perspective view of a unit tray 20 of a gas ventilation tray system covered with a layer of mica 30. The mica 30 has slots 56 that receive the parallel ribs 32 of the unit tray 20. The mica 30 obstructs the ventilation openings 28 in the unit tray 20 and faces the ventilation ends of the battery cells 16. If a battery cell 16 experiences a thermal event that causes the unit vent to burst, the mica bursts to allow the battery cell to ventilate into the ventilation channel 26. The mica 30 can be used to direct the air ventilated through the air vents 40 in the seam 38 between the unit trays further away. Specifically, the mica may include ventilation holes 56 to allow air to escape from the air vents 40 or other holes 45 in the seam 38.

[0065] Reference Figure 8 and 9 , a semi-permeable medium 60 (such as open-cell foam, felt, woven or knitted fabric, non-woven fabric, paper, or other selected membrane materials) can be inserted between rows of the battery cells 16 and / or over the top of the seam 38 at the air vents 40. The semi-permeable medium 60 allows air to pass through but obstructs the passage of the filling foam injected into the battery module 10.

[0066] Figure 10 is a bottom perspective view of an optional protruding shield feature 46 formed at the air vents 40 in the seam 38 of the unit tray 20. Figure 11 is a top perspective view of the air vents 40, having an optional protruding shield feature 47 formed in the seam 38 of the unit tray 20. Figure 12 is a plan view of the unit tray 20, showing the positions of a plurality of ventilation features 40 formed in the seam 38 of the unit tray 20.

[0067] The thermal ventilation system is sealed by a filling body after assembly to ensure that the gas ejected by the unit during a thermal event remains within the ventilation system. Among them, the width of the opening in this path is less than 1 mm in at least one direction, or ideally less than 0.1 mm.

[0068] The foregoing description is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or its use. The broad teachings of the present disclosure may be implemented in a variety of forms. Thus, while the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited because other modifications will become apparent after studying the drawings, the specification, and the appended claims. It should be understood that one or more steps within a method may be performed in a different order (or simultaneously) without changing the principles of the present disclosure. Additionally, while each of the embodiments above is described as having certain features, any one or more of those features described with reference to any embodiment of the present disclosure may be implemented in and / or combined with the features of any one of the other embodiments, 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 present disclosure.

[0069] Various terms are used to describe the spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.), including "connected", "joined", "coupled", "adjacent", "next to", "on top of", "above", "below", and "disposed". Unless explicitly described as "direct", when describing the relationship between a first and a second element in the foregoing disclosure, the relationship may be a direct relationship in which no other intermediate elements exist between the first and second elements, but may also be an indirect relationship in which one or more intermediate elements exist (spatially or functionally) between the first and second elements. 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, said housing including a sidewall structure, a top shear plate, and a bottom shear plate; a ventilation tray assembly, said ventilation tray assembly disposed within the housing and including a plurality of unit trays and a plurality of ventilation trays, the plurality of unit trays and the plurality of ventilation trays combined to define a plurality of ventilation channels therebetween, the unit tray including a base plate having a plurality of ventilation openings in communication with one of the plurality of ventilation channels, the ventilation tray assembly including an air vent passing through a hole in the base plate and a seam between the base plates of the unit trays; a plurality of battery cells, each having an end with a vent that aligns with one of the ventilation openings in the base plate of the unit tray; and a potting foam, dispersed within the housing and between the batteries.

2. The battery module according to claim 1, wherein, The unit tray includes a plurality of parallel ribs extending from the base plate of the unit tray, and the ventilation tray includes a base plate and a plurality of parallel ribs extending from the base plate of the ventilation tray, and the plurality of parallel ribs of the unit tray and the plurality of parallel ribs of the ventilation tray are combined to form the plurality of ventilation channels.

3. The battery module according to claim 1, wherein, The air vent includes a plurality of air vents, each including a protruding protective cover extending from an edge of the base plate of the unit tray.

4. The battery module according to claim 1 further includes a mica layer covering the base plate of the unit tray, and wherein, The air vent is defined between a seam between the unit trays and a mica layer.

5. The battery module according to claim 1, further comprising a semi-permeable medium extending between rows of the plurality of battery cells and adjacent to the plurality of unit trays.

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

7. The battery module according to claim 1, wherein, The air vent includes a plurality of air vents located in a central region of the battery housing.

8. The battery module according to claim 1, wherein, The width of the air vent in at least one direction is less than 1 mm.

9. The battery module according to claim 1, wherein The ventilation tray includes a base plate 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 unit tray to define the plurality of ventilation channels.

10. The battery module according to claim 1, wherein, The air vent is formed by stacking stepped features along adjacent edges of the base plate of the unit tray.

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