This disclosure relates to a method and system for battery thermal management.
A variety of battery cells are available to power vehicles. For example, lithium-ion batteries are known to be provided as rechargeable batteries in electrical vehicles. Lithium-ion batteries generate high amounts of heat during operation, which can greatly deteriorate performance of the batteries. Many such battery systems use conventional fluid cooling systems, such as liquid cooling, in an effort to provide heat management capacity and efficiency.
However, conventional fluid cooling systems for rechargeable lithium-ion batteries encounter problems as these systems use complex technology. For example, conventional fluid cooling systems for lithium-ion batteries encounter problems with failure modes related to leaking radiators and problems associated with maintaining an optimal temperature range in battery packs. In addition, it is troublesome for these systems to provide uniform temperature distribution, which impacts performance of battery packs.
In sum, existing cooling systems are complex, use radiators that may leak fluid, and may not adequately provide cooling of batteries.
Some embodiments advantageously provide a method and system for battery thermal management.
According to one aspect, a battery cooling system is provided. The battery cooling system comprises a first stack of battery cells and a second stack of battery cells; and a thermal exchanger comprising a thermal exchanger leg portion and a thermal exchanger foot portion, the thermal exchanger leg portion being disposed between and thermally coupled to adjacent lateral sides of the first and second stacks, and the thermal exchanger leg portion comprising a leg length that extends from a top to a bottom of the adjacent lateral sides to transfer heat energy from the battery cells of the first and second stacks to the thermal exchanger foot portion, and the thermal exchanger foot portion being disposed within and thermally coupled to a cooling fluid flow channel defined by a battery housing, and the thermal exchanger foot portion comprising a cooling fin element configured to transfer heat energy from the thermal exchanger leg portion into the cooling fluid flow channel.
In some embodiments, the thermal exchanger leg portion has a planar surface shape. In some embodiments, the thermal exchanger foot portion has a non-planar waveform surface shape. In some embodiments, the thermal exchanger is a stamped thermally conductive structure.
According to another aspect, a radiator for a battery is provided. The radiator comprises a thermal exchanger comprising a thermal exchanger leg portion and a thermal exchanger foot portion, the thermal exchanger leg portion comprising a planar surface shape configured to be disposed between and thermally coupled to adjacent lateral sides of a first and a second stack of battery cells, and the thermal exchanger leg portion comprising a leg length configured to extend from a top to a bottom of the adjacent lateral sides to transfer heat energy from the battery cells of the first and second stacks to the thermal exchanger foot portion, and the thermal exchanger foot portion comprising a cooling fin element having a non-planar waveform surface shape configured to transfer heat energy from the thermal exchanger leg portion into a cooling fluid flow channel.
In some embodiments, the thermal exchanger foot portion and the thermal exchanger leg portion form an L-shaped structure. In some embodiments, the thermal exchanger foot portion extends away from the thermal exchanger leg portion in a first direction and the thermal exchanger further comprises a second thermal exchanger foot portion that extends away from the thermal exchanger leg portion in a second direction that is opposite to the first direction. In some embodiments, the thermal exchanger foot portions and the thermal exchanger leg portion form a T-shaped structure.
According to yet another aspect, a method of manufacturing and/or assembling a battery cooling system is provided. The method comprises providing the thermal exchanger of any one of the embodiments disclosed herein. The method further includes providing a battery housing, the battery housing being molded to define a leg portion receiver and at least part of a cooling fluid flow channel, the leg portion receiver sized, shaped and/or configured to receive a leg portion of the thermal exchanger therein and the at least part of the cooling fluid flow channel sized, shaped and configured to receive a foot portion of the thermal exchanger therein. The method further includes inserting the thermal exchanger into the battery housing to press fit the respective leg portion into the leg portion receiver between a first stack of battery cells and a second stack of battery cells and to include the foot portion in the at least part of the cooling fluid flow channel. The method further includes after inserting the thermal exchanger, assembling a base plate onto the molded battery housing to enclose the thermal exchanger in the battery housing.
According to one aspect, a thermal exchanger for a battery comprising one or both of a first stack and a second stack of battery cells is described. The thermal exchanger comprises a thermal exchanger leg portion and a thermal exchanger foot portion. The thermal exchanger leg portion is positionable to thermally couple to one or both of the first stack and the second stack of battery cells. The thermal exchanger leg portion is arranged to transfer thermal energy from one or both of the first stack and second stack to the thermal exchanger foot portion.
According to another aspect, a battery cooling system comprises one or both of a first stack of battery cells and a second stack of battery cells and a thermal exchanger. The thermal exchanger comprises a thermal exchanger leg portion and a thermal exchanger foot portion. The thermal exchanger leg portion is thermally coupled to the one or both of the first stack and the second stack of battery cells. The thermal exchanger leg portion is arranged to transfer thermal energy from one or both of the first stack and second stack to the thermal exchanger foot portion. The battery cooling system further includes a battery housing that defines at least part of a cooling fluid flow channel. The thermal exchanger and the one or both of the first stack and the second stack are positioned within the battery housing. The thermal exchanger foot portion is positioned within cooling fluid flow channel.
According to one aspect, a method of manufacturing a battery cooling system for a battery is described. The battery comprises a cooling fluid flow channel, a battery housing, and a first stack and a second stack of battery cells. The battery housing comprises a leg portion receiver. The battery cooling system comprises a thermal exchanger. The thermal exchanger includes a thermal exchanger leg portion and a thermal exchanger foot portion. The method comprises molding the battery housing to define the leg portion receiver and at least part of the cooling fluid flow channel. The leg portion receiver is arranged to receive the thermal exchanger leg portion of the thermal exchanger therein. The at least part of the cooling fluid flow channel being arranged to receive the thermal exchanger foot portion therein. The method further includes inserting the thermal exchanger into the battery housing by press fitting the thermal exchanger leg portion into the leg portion receiver between the first stack of battery cells and the second stack of battery cells and including the thermal exchanger foot portion in the at least part of the cooling fluid flow channel.
A more complete understanding of embodiments described herein, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:
One or more embodiments provide a thermal management solution. In some embodiments, the thermal management solution provides an integrated, “molded in housing” thermal management solution. Some other embodiments provide a sealed, and efficient fluid (e.g., liquid) cooling solution. In some embodiments, the heat exchangers transfer heat from the battery cells to a fluid cooling path (e.g., using components) and without the complexity of over-molding. Some other embodiments provide individual heat exchangers in a cooling fluid (e.g., coolant) path which permits the heat exchangers to be placed within the cooling fluid to provide a substantially common average temperature.
It may also be possible, in some embodiments, to have a heat exchanger within the cooling fluid path that extends to high temperature electronics components.
Some embodiments provide a, efficient, sealed thermal management solution. Some embodiments provide a thermal management solution by using simple stamped heat exchanger(s) in proximity to the battery cells and within the cooling fluid path. Having at least a part of the formed heat exchanger within (i.e., directly contacting the fluid in) the cooling fluid path enables efficient thermal conduction of heat. At the same time, in some embodiments, since the cooling fluid path is molded into the battery housing and there is no direct contact path of the fluid to the battery cells (and/or high temperature electronics components), a safer solution (as compared to direct contact liquid cooling solutions) without the failure modes related to leaking radiators is provided.
In some embodiments, instead of having two heat exchangers for each set of battery cell stacks, the heat exchangers may be combined as a single, folded heat exchanger in an alternative embodiment, as described in more detail below.
Before describing in detail exemplary embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to battery thermal management. Accordingly, the system and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.
As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
In some embodiments, the term to “couple” (and/or coupled and/or coupling) is used and may refer to at least to joining, affixing, attaching, connecting, placing in contact, bringing in contact two or more elements or components. In some other embodiments, the term “thermally couple” is used and may refer to bringing one or more elements in contact with each other such that thermal energy may be exchanged between the elements. For example, a first element may be directly/indirectly in contact with a second element, where the first element is in contact with the second element and transfers thermal energy (e.g., heat) to the second element. The second element may be configured to receive the thermal energy and/or transfer the thermal energy to a third element. Thus, thermal coupling may refer to arranging elements such that the thermal conductivity of at least one of the elements can be used to achieve thermal energy exchange. For example, a thermal exchanger may be thermally coupled to a battery pack having a predetermined thermal energy (e.g., heat), where the thermal exchanger absorbs at least a portion of the thermal energy and transfers the thermal energy to a cooling fluid and/or cooling fluid flow channel. In this nonlimiting example, the thermal exchanger is thermally coupled to the battery pack, the cooling fluid, and cooling fluid flow channel.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Some of the embodiments contemplated herein will now be described more fully with reference to accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.
Although the subject matter described herein may be implemented in any appropriate type of battery cooling system using any suitable components, the embodiments disclosed herein are described in relation to a fluid cooling system, such as a liquid coolant cooling system (e.g., for lithium-ion battery cells or any other type of battery cells) as illustrated in
Some embodiments include a thermal management system which provides a thermal management solution. In one or more embodiments, the thermal management system is an electrical vehicle (EV) thermal management system such as a thermal management system that is comprised in the EV and configured to provide cooling of one or more battery packs of the EV. The thermal management system of the present disclosure is beneficial at least because the thermal management system has a less complex structure and a less complex construction method, as compared to existing EV thermal management systems,. For example, the simpler structure of the thermal management system comprises a housing (e.g., molded housing),, cooling channels, and a fluid cooling manifold with a radiator (i.e., thermal exchanger).
In some embodiments, cooling channels are molded into a bottom of the housing. In some embodiments, stamped radiators are inserted into a molded housing to provide a cooling path from the heat generating elements (battery cells and/or heat generating electrical components) to the cooling fluid. In some embodiments, safety may be improved (when compared to existing systems) by not having a failure mode where cooling fluid (e.g., coolant) touches the battery cells, as may be the case in cooling systems where cooling fluid (e.g., liquid coolant) directly contacts the battery cells.
Some embodiments include a battery cooling system 10 (hereinafter also referred to as system 10), as illustrated in
In some embodiments, the cooling fluid flow channel 20 is arranged through a single-level of the battery housing 16, e.g., bottom of the battery housing 16 (and/or base plate 18). In other embodiments, the cooling fluid flow channel 20 is arranged through multiple hierarchical levels of the battery housing 16. For example, in one hierarchical level arrangement, the cooling fluid flow channel 20 may be defined by the bottom of the battery housing 16 and base plate 18. In another hierarchical level arrangement, the cooling fluid flow channel 20 may be defined by lateral sides (or walls) of battery stacks 12, 14 and the battery housing 16. Yet, in another hierarchical level arrangement, the cooling fluid flow channel 20 may be defined by top portions of the battery housing 16 and a cover coupled (e.g., sealed) to the top portions of the housing, etc. In other words, in alternative embodiments, the cooling fluid flow channel 20 may be defined by and/or extend to other portions of the battery housing 16, such as a top portion and/or one or more lateral sides of the battery housing 16.
In some embodiments, a one-way valve is integrated into the cooling system loop, i.e., in fluid communication with the cooling fluid flow channel 20 and/or cooling fluid flow channel 20 inlet to enable emergency responders to provide additional cooling directly to the energy storage system thermal management when responding to an accident.
The system 10 further includes a thermal exchanger 22, which may operate as a radiator. The thermal exchanger 22 includes a thermal exchanger leg portion 24 and a thermal exchanger foot portion 26. The thermal exchanger foot portion 26 and the thermal exchanger leg portion 24 may form an L-shaped structure. In some embodiments, the base plate 18 may be assembled to the battery housing 16 after press fitting the thermal exchangers 22 into e.g., L-shaped receivers defined by the battery housing 16, as shown in
The thermal exchanger leg portion 24 is disposed between and thermally coupled to adjacent lateral sides of the first and second stacks 12, 14. The thermal exchanger leg portion 24 may have a leg length, L, that extends from a top to a bottom of the adjacent lateral sides to transfer heat energy from the battery cells of the first and second stacks 12, 14 to the thermal exchanger foot portion 26. In some embodiments, the thermal exchanger leg portion 24 has a planar surface shape. The thermal exchanger leg portion 24 is preferably sized to be press fit into the battery housing 16 between the first and second stacks 12, 14 to transfer heat from the battery cells toward the cooling fluid flow channel 20 and to be retained in place during manufacturing and/or operation and/or service of the battery. In some embodiments, the battery housing 16 may also be made of and/or contain a thermally conductive material so that heat generated from the battery cells can be transferred efficiently to the thermal exchanger leg portion 24 (and/or thermal exchanger foot portion 26). In some embodiments, the battery housing 16 may be or include a polymer, e.g., plastic.
In some embodiments, the thermal exchanger leg portion 24 is disposed external to the cooling fluid flow channel 20, being disposed between opposite walls 28, 30 of the battery housing 16, which walls 28, 30 house the first and second stacks 12, 14, respectively. The battery housing 16 may be arranged to define a leg portion receiver 32 that is sized, shaped and configured to receive a respective thermal exchanger leg portion 24 therein, via e.g., press fitting assembly. As noted above, in some embodiments, adhesive and/or sealant may be applied around thermal exchanger 22 to further limit the risk of fluid leaks with the receiver.
The battery housing 16 houses the battery cells 31 and, along with the base plate 18, encloses the battery cells 31 and the cooling fluid flow channel 20. The battery housing 16 may define at least one cooling fluid inlet port 34 and at least one cooling fluid outlet port 36, as shown in
In some embodiments, as shown in
The thermal exchanger foot portion 26 may include a cooling fin element 33 configured to transfer heat energy from the thermal exchanger leg portion 24 to the cooling fluid flow channel 20. In some embodiments, the cooling fin element 33 is sized, shaped and/or configured to increase the surface area of the thermal exchanger foot portion 26 arranged to be in contact with the cooling fluid (e.g., in the cooling fluid flow channel 20). Thermal conductivity of the thermal exchanger foot portion 26 increases when its surface area is increased, and thus, a greater amount of thermal energy per unit of time can be transferred to the cooling fluid and/or cooling fluid flow channel 20. Thus, the thermal energy from battery stacks 12, 14 that is received by the thermal exchanger leg portion 24 and transferred to the thermal exchanger foot portion 26 can be conducted (e.g., released, transferred) to the cooling fluid at a faster rate (than without the increased surface area). Put differently, the surface area of the thermal exchanger foot portion 26 may be increased to increase the cooling rate of the battery packs. In a nonlimiting example, when the surface area of the thermal exchanger foot portion 26 is increased by a predetermined percentage, X, thermal conductivity is increased by a factor, Y, and the cooling rate of the battery stacks 12, 14 is increased by a factor, Z.
In some embodiments, the cooling fin element 33 may have a non-planar waveform surface shape, or other shape, configured to increase the surface area of the exchanger foot portion 26 within a predefined volume (i.e., in the cooling fluid flow channel 20). The non-planar waveform surface shape may be uniform or non-uniform. A non-uniform waveform shape may include waves (i.e., fins) having a greater amplitude (e.g., displacement) than other waves (i.e., fins) of the exchanger leg portion 24. In some embodiments, the exchanger leg portion 24 comprises a first cooling fin element 33a (e.g., wave of a waveform, fin), a second cooling fin element 33b (e.g., wave of a waveform, fin), each having a same width. The first cooling fin element 33a has a greater amplitude than the amplitude of the second cooling fin element 33b. The surface area corresponding to each one of the first and second cooling fin elements 33a, 33b is directly proportional to the respective amplitude. Thus, in this nonlimiting example, the surface area of the first cooling fin element 33a is greater than the surface area of the second cooling fin element 33b. In addition, the thermal conductivity of the first cooling fin element 33a is greater than the thermal conductivity of the second cooling fin element 33b. Further, the overall surface area and/or thermal conductivity of the exchanger leg portion 24 is increased when having a non-planar waveform surface shape (e.g., when compared to a flat shape).
In another embodiment, the exchanger leg portion 24 (having a non-uniform waveform shape) has a plurality of cooling fin elements 33. Each cooling fin element 33 corresponds to a peak of the non-uniform waveform. Each peak of the non-uniform waveform shape has a corresponding amplitude, where the first peak is the peak that is closest to the exchanger leg portion 24, and the last peak is the peak furthest from the exchanger leg portion. In a nonlimiting example, the amplitude of each peak decreases when compared to a peak that is closer to the thermal exchanger leg portion 24. That is, the amplitude of the peaks decreases as the distance between the peak and the thermal exchanger leg portion 24 increases. Thus, the first peak offers a greater surface area than other peaks, e.g., so that the thermal energy being received from the thermal exchanger leg portion 24 can be quickly released to the cooling fluid.
Other shapes of the cooling fin element 33 may include rectangular fins, tubular fins, radial fins, a mesh, or any other shape. In a nonlimiting example, the thermal exchanger foot portion 26 comprises a plurality of cooling fin elements 33 (e.g., planar fins) that protrude or extend away from the thermal exchanger foot portion 26 into the cooling fluid flow channel 20 (and/or cooling fluid). Each planar fin has a surface area. The location, size, and surface area of each planar fin may depend on one or more characteristics of the cooling fluid flow channel 20 and cooling fluid. For example, some characteristics may include shape, volume, and material of the cooling fluid flow channel 20, location of inlets/outlets of cooling fluid with respect to the thermal exchanger foot portion 26 and/or cooling fin elements 33 (e.g., planar fins), characteristics of the cooling fluid (e.g., freezing point, boiling point, pH, composition, flow rate at which the cooling fluid travels through the cooling fluid flow channel 20, etc.). In some embodiments, the angle at cooling fin element faces the flow vector of the cooling fluid is dynamically adjustable based on the characteristics of the cooling fluid flow channel 20 and/or cooling fluid, temperature of battery cells 31, battery stacks 12, 14, cooling fluid flow rate, etc.
Battery cooling system 10 may further include cooling fluid ports (or thermal management fluid ports) such as cooling fluid inlet port 34 and cooling fluid outlet port 36. In some embodiments, cooling fluid inlet port 34 is arranged to receive a thermal management fluid such as a cooling fluid (i.e., entering cooling fluid 35). In some embodiments, cooling fluid outlet port 36 is arranged to release the thermal management fluid such as the cooling fluid (i.e., released cooling fluid 36, which may be the same as entering cooling fluid 35 but having absorbed thermal energy from thermal exchanger 22. In some embodiments, the functions of cooling fluid inlet/outlet ports 34, 36 may be reversed such that cooling fluid outlet port 36 provides the functions of cooling fluid inlet port 34, and vice versa. Cooling fluid inlet/outlet ports 34, 36 may be in fluid communication with one or more components of battery cooling system 10 such as any of the components shown in
Further, each flow director 40 may have one or more shapes having one or more characteristics such as airfoil/hydrofoil fluid dynamics. For example, flow directors 40 may be shaped as an airfoil (e.g., when cooling fluid is a gas) or a hydrofoil (e.g., when cooling fluid is a liquid). Being shaped as an airfoil or hydrofoil may force the particles of the cooling fluid to travel a similar speeds or flows over and under the flow director such that uniform flow is achieved between the cooling fluid that flows over and under the flow directors 40 even though the flow path is curved. In addition, the shape of the flow directors 40 may be determined based on the cooling fluid characteristics and/or characteristics of the battery cooling system 10 such as acceptable pressure drop of the battery cooling system 10. Pressure drop may refer to a difference of pressures of the cooling fluid between two points of the battery cooling system 10 (e.g., as cooling fluid inlet port 34 and cooling fluid outlet port 36). The pressure drop may correspond to a flow rate of the cooling fluid which may be adjustable by the flow directors 40.
Referring now primarily to
In the second embodiment, the system 10 may include a plurality of stacks 12, 14 of battery cells and a plurality of thermal exchangers 22a-n (where ‘a’ is 1 and ‘n’ can be any number greater than 1) arranged inside a battery housing 16. However, unlike in the example alternating arrangement described with respect to the first embodiment, each thermal exchanger 22 in the second embodiment may be disposed to thermally couple, in a heat exchanging relationship, to each stack in the plurality of stacks 12, 14 in a non-alternating arrangement, as shown in
Referring now primarily to
In step S804, the method includes inserting the thermal exchanger 22 into the battery housing 16 to press fit the respective thermal exchanger leg portion 24 into the leg portion receiver 32 between a first stack 12 of battery cells and a second stack 14 of battery cells and to include the thermal exchanger foot portion 26 in the cooling fluid flow channel 20. In step S806, the method includes, after inserting the thermal exchanger 22, assembling the base plate 18 onto the molded battery housing 16 to enclose the thermal exchanger 22 and the cooling fluid flow channel 20 in the battery housing 16. For example, the base plate 18 may be assembled to the battery housing 16 after press fitting the thermal exchanger 22 into the battery housing 16. Such assembly can include gluing, welding or any other arrangement for coupling (e.g., releasably coupling or affixing) the base plate 18 to the battery housing 16 to create a fluid tight seal and path through the cooling fluid flow channel 20.
Referring now primarily to
In some embodiments, the battery cooling system 10 further includes one or more of a base plate 18, a cooling fluid inlet port 34, and a cooling fluid outlet port 36. The method further includes one or more of steps: (A) after inserting the thermal exchanger 22, coupling the base plate 18 to the molded battery housing 16, where the coupling of the base plate 18 encloses the thermal exchanger 22 in the battery housing 16 and further defines the cooling fluid flow channel 20; (B) inserting the first stack 12 and the second stack 14 in the battery housing 16, where the inserted first and second stacks 12, 14 have adjacent sides facing the thermal exchanger leg portion 24 of the thermal exchanger 22; and (C) one of forming on, coupling to, and molding on the battery housing 16 the cooling fluid inlet port 34 and the cooling fluid outlet port 36. The cooling fluid inlet port 34 and the cooling fluid outlet port 36 are in fluid communication with the cooling fluid flow channel 20 and at least the thermal exchanger leg portion 26.
The following is a nonlimiting list of example embodiments:
Some embodiments are described herein with reference to flowchart illustrations and/or block diagrams of methods of manufacturing and/or assembling. It is to be understood that the functions/acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and/or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.
It will be appreciated by persons skilled in the art that the present embodiments are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings and the following claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2023/060021 | 1/3/2023 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63297020 | Jan 2022 | US |