Passive cooling structure packaging system for battery cell

Abstract

The invention relates to a passive cooling structure packaging system for battery cells. A passive cooling system for battery cells includes a housing defining a cavity in which a plurality of battery cells are disposed. Each battery cell is surrounded by a porous medium, and a phase change material is disposed within a space defined by the porous medium. A cold plate is disposed at the top of the cavity to cool the vaporized phase change material and change the vapor into a liquid.

Description

Technical Field

[0001] The information provided in this section is for the purpose of generally presenting the background of the present disclosure. To the extent described in this section, the work of the presently named inventors, as well as aspects of this specification that may not otherwise qualify as prior art at the time of filing, are not explicitly or implicitly admitted to be prior art against the present disclosure.

[0002] The present disclosure relates to a passive cooling structure packaging system for a battery cell. Background Art

[0003] Currently, battery cells in electric vehicles are thermally managed by forced liquid cold plates. These cold plates are usually in the form of strips placed between the cells. The circulation of the coolant requires a pump, and the channels themselves require additional components within the pack. The cooling strips are usually a conductive metal.

[0004] Heat pipes are a related heat transfer technology that utilizes phase changes of fluids in a closed volume system. In this system, liquid is transported through a wick by capillary action in a porous medium. Two-phase immersion cooling systems operate similarly but do not rely on capillary forces to transport liquid. The present disclosure uses a similar thermal cycle. Summary of the invention

[0005] According to one aspect of the present disclosure, a passive cooling system for a battery cell includes a housing defining a cavity, wherein a plurality of battery cells are disposed in the cavity. Each battery cell is surrounded by a porous medium, and a phase change material is disposed in a space defined by the porous medium. A cold plate is disposed at the top of the cavity to cool the evaporated phase change material and turn the vapor into a liquid.

[0006] According to another aspect, the porous medium defines a plurality of vapor channels along each of the plurality of battery cells.

[0007] According to another aspect, the plurality of vapor channels extend vertically upward along a side of the battery cell.

[0008] According to another aspect, a subdivision structure is provided in the cavity for subdividing the cavity into a plurality of separate compartments.

[0009] According to another aspect, the porous medium surrounding the battery cell comprises an open cell foam.

[0010] According to another aspect, the open cell foam includes one of epoxy, polyurethane, and silicone.

[0011] According to another aspect, the porous medium surrounding the battery cell includes one of an aerogel and a non-organic microporous structure.

[0012] According to another aspect, the vapor changing material is a dielectric.

[0013] According to another aspect, the phase change material has a boiling point between 30-60° C. at ambient pressure.

[0014] According to another aspect, the cold plate is liquid cooled.

[0015] According to another aspect, the cold plate is partially exposed to the environment for cooling.

[0016] According to another aspect, the cold plate is a top enclosure of the housing.

[0017] According to another aspect of the present disclosure, a method of manufacturing a passive cooling system for a battery cell includes: applying a plurality of strips of sacrificial material to an outer surface of a plurality of battery cells; and inserting the plurality of battery cells into a cavity of a housing. A porous medium is formed in the cavity of the housing around the plurality of battery cells. The plurality of strips of sacrificial material are removed from the plurality of battery cells to form a plurality of channels in the porous medium along the surface of the plurality of battery cells, and the porous medium is filled with a phase change material.

[0018] According to another aspect, the sacrificial material includes one of a water soluble polymer, a combustible solid, a meltable wax, and a thermally degradable polymer.

[0019] According to another aspect, a cold plate is positioned over the cavity of the housing.

[0020] According to another aspect, a subdivision structure is inserted into the cavity for subdividing the cavity into a plurality of separate compartments, each of which comprises a subset of the plurality of battery cells.

[0021] The present invention also includes the following technical solutions:

[0022] Solution 1. A passive cooling system for a battery cell, comprising:

[0023] a housing defining a cavity;

[0024] a plurality of battery cells disposed in the cavity of the housing;

[0025] Each of the battery cells is surrounded by a porous medium;

[0026] a phase change material disposed in a space defined by the porous medium; and

[0027] A cold plate is disposed at the end of the cavity.

[0028] Option 2. A passive cooling system for a battery cell according to Option 1, wherein the porous medium defines a plurality of vapor channels along each of the plurality of battery cells.

[0029] Option 3. A passive cooling system for a battery cell according to Option 2, wherein the plurality of vapor channels extend vertically upward along the side of the battery cell.

[0030] Option 4. The passive cooling system for a battery cell according to Option 1 further includes a subdivision structure arranged in the cavity for subdividing the cavity into a plurality of separate compartments.

[0031] Option 5. A passive cooling system for a battery cell according to Option 1, wherein the porous medium surrounding the battery cell comprises an open-cell foam.

[0032] Option 6. A passive cooling system for a battery cell according to Option 5, wherein the open-cell foam comprises one of epoxy resin, polyurethane and silicone.

[0033] Option 7. A passive cooling system for a battery cell according to Option 1, wherein the porous medium surrounding the battery cell comprises one of an aerogel and a non-organic microporous structure.

[0034] Option 8. A passive cooling system for a battery cell according to Option 1, wherein the phase change material is a dielectric.

[0035] Option 9. A passive cooling system for a battery cell according to Option 1, wherein the phase change material has a boiling point between 30-60°C at ambient pressure.

[0036] Option 10. A passive cooling system for a battery cell according to Option 1, wherein the cold plate is liquid cooled.

[0037] Embodiment 11. The passive cooling system for a battery cell according to Embodiment 1, wherein the cold plate is partially exposed to the environment for cooling.

[0038] Option 12. The passive cooling system for a battery cell according to Option 1, wherein the cold plate is a top shell of the housing.

[0039] Scheme 13. A method for manufacturing a passive cooling system for a battery cell, comprising:

[0040] applying a plurality of strips of sacrificial material to an outer surface of a plurality of battery cells;

[0041] inserting the plurality of battery cells into the cavity of the housing;

[0042] forming a porous medium within the cavity of the housing around the plurality of battery cells; and

[0043] removing the plurality of strips of sacrificial material from the plurality of battery cells to form a plurality of channels within the porous medium along surfaces of the plurality of battery cells;

[0044] The porous medium is filled with a phase change material.

[0045] Option 14. A method according to Option 13, wherein the sacrificial material includes one of a water-soluble polymer, a combustible solid, a meltable wax and a thermally degradable polymer.

[0046] Embodiment 15. The method according to embodiment 13 further includes placing a cold plate above the cavity of the housing.

[0047] Option 16. The method of Option 15, wherein the cold plate is liquid cooled.

[0048] Embodiment 17. The method according to embodiment 15, wherein the cold plate is partially exposed to the environment for cooling.

[0049] Embodiment 18. The method according to embodiment 13 further includes inserting a subdivision structure in the cavity for subdividing the cavity into a plurality of separate compartments, each of which includes a subset of the plurality of battery cells.

[0050] Option 19. The method according to Option 13, wherein the phase change material is a dielectric.

[0051] Option 20. The method according to Option 13, wherein the porous medium is an open-cell foam.

[0052] Other areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings.The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The present disclosure will be more fully understood through the detailed description and accompanying drawings, in which:

[0054] Figure 1 is a schematic cross-sectional view of a passive battery cooling packaging system for a battery cell;

[0055] Figure 2 is a schematic plan view of a cell arrangement structure of a passive battery cooling packaging system for a battery cell;

[0056] Figure 3is a schematic diagram of a battery cell arrangement structure of a passive battery cooling packaging system with a non-porous coolant containment layer; and

[0057] Figures 4A-4C A process for forming vapor channels within a porous medium is illustrated.

[0058] In the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0059] refer to Figure 1 and Figure 2 , the battery cell 10 is shown in a housing 12 having a porous medium, such as an open-cell foam 14, in a cavity surrounding the battery cell 10. The open-cell foam 14 may include one of epoxy, polyurethane, silicone, aerogel, and a non-organic microporous structure. A plurality of vapor channels 16 are formed in the open-cell foam 14 along the side surface of the battery cell. A cold plate 18 is disposed in the top of the housing 12. An electrical bussing system 20 is contained in the cavity and is connected to the battery cell 10. The electrical bussing system 20 may be part of the cold plate 18. The cold plate 18 may be liquid-cooled and may be partially exposed to the environment for cooling. The cold plate 18 may also be the top enclosure of the housing 12.

[0060] The phase-change working fluid 22 fills the pores of the open-cell foam 14 surrounding the battery cell 10 . Figure 2 A plurality of battery cells 10 are shown within a housing 12, wherein an open cell foam 14 includes a plurality of vapor channels 16 extending upwardly along the side surface of each battery cell 10. The vapor change material may be a dielectric and have a boiling point between 30-60° C. at ambient pressure. Vapor change materials of this type are known in the art.

[0061] In operation, when the battery 10 heats up during charging and discharging, the phase change fluid 22 heats up and turns into vapor. The vapor rises along the vapor channel 16 following arrow A and is cooled by the cold plate 18 at the top of the housing 12. The cooled vapor then condenses on the cold plate and drips into the open cell foam 14. Capillary action at the evaporation point within the open cell foam transports the fluid back to the cell wall following arrow B.

[0062] refer to Figure 3, the cavity of the housing 12 is shown to also include a subdivision structure 24 for subdividing the cavity into a plurality of individual compartments, each of which contains a plurality of battery cells 10. The subdivision structure 24 maintains a uniform coolant level throughout the pack even in the case of long-term uneven vehicle exposure, such as when the vehicle is parked on a slope. In addition, the subdivision structure can reduce sloshing of the phase change liquid 22 during vehicle operation.

[0063] refer to Figures 4A-4C , the process for forming the vapor channels 16 along the surface of the battery cell 10 will now be described. Figure 4A During the assembly process shown in , a plurality of strips of sacrificial material 30 are formed on the side surfaces of the battery cell 10. Figure 4B As shown in FIG. 1 , a porous material 14 is formed around the battery cell 10 and the sacrificial material 30 . Figure 4C , the sacrificial material 30 is removed to form the channel 16. The sacrificial material 30 may be wax, a water-soluble material, a combustible material or other heat-degradable material. The sacrificial material may be melted, dissolved, degraded or otherwise removed to provide a void defining the channel 16.

[0064] The foregoing description is merely illustrative in nature and is in no way intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in a variety of forms. Therefore, although the present disclosure includes specific examples, the actual scope of the present disclosure should not be limited thereto, because other modifications will become apparent based on the study of the drawings, the specification and the following claims. It should be understood that one or more steps within the method may be performed in a different order (or simultaneously) without changing the principles of the present disclosure. In addition, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the present disclosure may be implemented in any other embodiment and / or combined with the features in any other embodiment, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the permutation of one or more embodiments with each other is still within the scope of the present disclosure.

[0065] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including "connected," "engaged," "coupled," "adjacent," "next to," "on top of," "above," "below," and "disposed." Unless explicitly described as "directly," when describing the relationship between a first and a second element in the above disclosure, the relationship may be a direct relationship in which no other intervening elements exist between the first and second elements, but may also be an indirect relationship in which one or more intervening 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 logic (A OR BOR C) using a non-exclusive logical 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 passive cooling system for a battery cell, comprising: a housing defining a cavity; a plurality of battery cells disposed in the cavity of the housing; Each of the battery cells is surrounded by a porous medium; a phase change material disposed in a space defined by the porous medium; as well as A cold plate is disposed at the end of the cavity.

2. The passive cooling system for a battery cell according to claim 1, wherein: The porous medium defines a plurality of vapor channels along each of the plurality of battery cells.

3. The passive cooling system for a battery cell according to claim 2, wherein: The plurality of vapor channels extend vertically upward along the sides of the battery cells.

4. The passive cooling system for a battery cell according to claim 1, further comprising a subdivision structure disposed in the cavity for subdividing the cavity into a plurality of separate compartments.

5. The passive cooling system for a battery cell according to claim 1, wherein: The porous medium surrounding the battery cells comprises an open-cell foam.

6. The passive cooling system for a battery cell according to claim 5, wherein: The open-cell foam includes one of epoxy, polyurethane and silicone.

7. The passive cooling system for a battery cell according to claim 1, wherein: The porous medium surrounding the battery cell includes one of an aerogel and a non-organic microporous structure.

8. The passive cooling system for a battery cell according to claim 1, wherein: The phase change material is a dielectric.

9. The passive cooling system for a battery cell according to claim 1, wherein: The phase change material has a boiling point between 30-60°C at ambient pressure.

10. The passive cooling system for a battery cell according to claim 1, wherein: The cold plate is liquid cooled.

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