Thermal fins for a battery device and a battery module including the thermal fins

Abstract

A thermal fin (26) for a battery device, comprising first and / or second contact units (28, 30) configured to prevent heat transfer between battery pack sub-assemblies and adapted to face-to-face contact with the first and second battery pack sub-assemblies, and a support unit (32) sandwiched between the first contact unit and the second contact unit (28, 30). The thermal fin (26) extends in a fin plane and has a fin length and a fin thickness in a cross-section along a longitudinal axis, and a thermal resistance in the fin plane is lower than a thermal resistance in a direction perpendicular to the fin plane, whereby the thermal fin is adapted to realize a thermal management function and a thermal safety function of the battery device.

Description

Technical Field

[0001] The fields to which the present disclosure generally relates include methods and assemblies for thermal management of the temperature of battery components and for thermal safety features that limit heat propagation between cells within a battery. More particularly, without limitation, the present invention relates to a battery module having a plurality of electrically interconnected battery cells, wherein the individual battery cells are temperature controlled by heat removal and heat insulation.

Background Art

[0002] In this application, the “thermal management” function and the purpose of “thermal management” are meant to maintain the battery and its individual sub-assemblies within desired temperature limits (minimum and maximum) and within a desired variation (ΔT) width between sub-assemblies. The “thermal safety” function is meant to limit heat propagation between battery sub-components, particularly from cell to cell, for the purpose of preventing a thermal runaway event (defined below).

[0003] In this context, the terms “battery cell,” “battery module,” “battery section,” and “battery pack” (as well as their shortened variants “cell,” “module,” “section,” and “pack”) are used to refer to components at various levels of a battery assembly. For example, a number of individual battery cells form the building blocks of a battery module. A plurality of battery modules (along with accessories) make up a battery pack.

[0004] In this application, a cell is the smallest unit of a battery pack that includes a single anode electrical connection and a single cathode electrical connection externally, or of a sealed housing that houses one or a plurality of pairs of anode elements and cathode elements. A cell is a single electrochemical unit, while a battery is composed of one or more electrically interconnected cells joined in series, parallel, or both, depending on the desired output voltage, output current, or output capacity.

[0005] The battery device can include one or more battery packs sized to supply power to a vehicle. A battery pack is composed of battery sections, a battery section can be composed of a number of battery modules, each battery module is composed of one or more battery cells, and these battery cells supply current to a load. These battery cells are electrically interconnected.

[0006] A battery pack is composed of sections, a section can be composed of a number of battery modules, each battery module is composed of one or more battery cells, and these battery cells supply current to a load. Those skilled in the art will understand that the number of battery cells in a battery module, battery section, battery pack, or related structure larger than a battery cell should match the power demand of the device receiving current from the battery, as well as the thermal operating requirements of the cells within the battery. In such a battery, the flow of current during both charging and discharging generates heat within the cells and within the cell interconnect system.

[0007] In electric vehicles (EVs), lithium-ion batteries composed of cells are used. The performance of lithium-ion battery cells is highly dependent on their temperature. When the cells overheat, their electrical performance may deteriorate, they may be damaged, and their lifespan may be shortened. Therefore, lithium-ion batteries require a thermal management system to maintain a constant temperature with a very small temperature deviation so that they can operate efficiently without being damaged or failing (the temperature distribution across the entire cell must be uniform with a maximum deviation of less than 5°C).

[0008] In addition, lithium-ion batteries may suffer from a failure called thermal runaway. The term thermal runaway event refers to an uncontrollable temperature rise within the battery system. Thermal runaway is a chain reaction within the battery cell that can be very difficult to stop once it starts. Thermal runaway occurs when the temperature inside the battery reaches a point where chemical reactions occur inside the battery. These chemical reactions generate even more heat, which raises the temperature further, causing more chemical reactions, which generate even more heat. During a thermal runaway event, the generation of heat within the battery system or battery cell exceeds the dissipation of heat, thus leading to a further temperature rise. Thermal runaway events can be caused by various conditions, including short circuits within the cell, improper use of the cell, physical abuse, manufacturing defects, or exposure of the cell to extreme external temperatures.

[0009] One of the important issues in manufacturing electric vehicles is the thermal management system and thermal safety system for the battery (lithium-ion batteries are widely used in particular in electric vehicles).

[0010] Thermal management is essential for the performance and operating lifespan of electric vehicle batteries, and several studies, disclosures, and patent documents have addressed this issue.

[0011] U.S. Patent No. 10,686,171 discloses a battery module comprising a plurality of bells (or a single battery) and a plurality of separator plates, each separator plate being inserted between two adjacent cells. The separator plate comprises through holes that create an air thermal resistance. The separator plate is made of a thermosetting resin and is capable of expanding in volume when the temperature of one cell exceeds 200 degrees Celsius.

[0012] Expansion at high temperatures may cause damage to the cells. In addition, heat transfer between cells is reduced, but only to a certain extent.

[0013] It is also known to use cooling fins to conduct heat away from the battery cells. The cooling fins can be made of a material with high thermal conductivity (or low thermal resistance) to transfer heat to a cooler or heat exchanger.

[0014] For example, U.S. Patent Application Publication No. 2011 / 0189525 discloses a heat exchanger structure disposed between opposing surfaces of first and second battery stacks for use in a battery unit. This heat exchanger defines one or more fluid flow paths and is used to dissipate heat.

[0015] It is also known to cool an electric vehicle battery by forced convection using a forced air refrigerant or a forced liquid coolant circulated through cooling passages. For example, documents U.S. Patent Application No. 2021 / 135307A1, U.S. Patent Application No. 2014 / 308551A1, CN102117945, and U.S. Patent Application No. 2008 / 305388A1 disclose liquid-cooled battery systems. U.S. Patent Application No. 2016 / 204483A1 also discloses cooling fins configured to receive a flow of a liquid refrigerant through refrigerant flow paths, and discloses inter-cell thermal insulation within a battery system using passive cooling such as conduction cooling, radiative cooling, or convective cooling without using active circulation of a cooling fluid.

[0016] In U.S. Patent Application Publication No. 2008 / 0305388, thin, substantially planar, but not necessarily flat, heat-conducting fins that contact individual battery cells conduct heat away from the cells to a heat exchanger that includes tubes containing a coolant fluid. The fins are connected to the tubes at the tips of the fins, and the tubes are outside the periphery of the cell pack.

[0017] In U.S. Patent Application Publication No. 2014 / 0308551, various embodiments disclose inter-cell thermal fins that incorporate coolant fluid conduction flow paths within the fins between adjacent cells. The fluid conduction flow paths are in fluid communication with a manifold outside the periphery of the cells.

[0018] U.S. Patent Application Publication No. 2021 / 0135307 also describes various embodiments in which a cooling fluid circulates through fluid channels within substantially planar cooling fins positioned between adjacent cells.

[0019] U.S. Patent Application Publication No. 20160204483 describes, in a plurality of embodiments, cooling fins with fluid flow paths for actively circulated refrigerant, and describes the addition of elements that allow for passive (e.g., gravity) flow of the refrigerant to mitigate the spread of thermal runaway between cells in the event that active (pump-fed) flow is lost.

[0020] CN102117945 discloses a device that uses anisotropic heat conduction and includes a composite heat-conductive plate having a heat-conductive layer and a heat-insulating layer. This composite heat-conductive plate can be disposed between two element cells.

[0021] These systems require complex manufacturing, and thus there is a continuing need to provide a cooling system that removes excessive heat from the cells and that implements a thermal management function by restricting heat transfer between battery cells or between battery modules, or between the battery pack and the rest of the vehicle.

[0022] JP 2020-072005 is directed to a heat transfer suppression sheet for a battery. JP 2020-072005 discloses a configuration including two flat sheets made of a heat-absorbing material or a heat-insulating material and a corrugated sheet extending between the two flat sheets. The corrugated sheet has the same heat-absorbing performance and / or heat-insulating performance as the flat sheet 20. Heat is absorbed for use in the evaporation of water or any material.

[0023] The materials of the different layers (flat sheet and corrugated sheet) are very specific. This heat transfer suppression sheet is particularly expensive and difficult to manufacture.

[0024] The present invention generally relates to thermal fins that enable cooling of individual battery cells, battery modules, or battery packs and that insulate between adjacent battery cells, between battery modules, or between battery packs. The present invention also relates to a battery module including such a heat insulator.

[0025] One aspect of the present invention involves the selection of specific materials and their arrangements to achieve thermal management and thermal safety functions. Thermal Interface Materials (TIMs) are useful for thermal management in electronic components because they enhance heat transfer from a heat-generating component (in this case, a battery cell) to a heat sink (heat sink, heat exchanger, or cooler). An important aspect in selecting a TIM for a specific application is knowing the ability of the material to transfer heat, which is often given by thermal conductivity and / or thermal resistance. Thermal conductivity is a material property that represents the ability of a given material to conduct heat. Materials with high thermal conductivity are good heat conductors. This property is independent of the size, shape, or orientation of the material in a homogeneous material, so thermal conductivity is an ideal value. Thermal conductivity is measured in units of watts per meter-kelvin.

[0026] Thermal resistance is simply the mathematical reciprocal of conductivity. Since both thermal conductivity and thermal resistance are functions of distance (note the "meter" in the denominator of watts per meter-kelvin), a thinner TIM transfers heat more efficiently than a thicker TIM. The thermal resistance of a structure is measured between a first point and a second point and varies depending on the thermal resistance of the individual homogeneous elements and all the contact resistances between them. When the thermal resistance of a structure is low, the structure is a good heat conductor. Factors such as surface roughness, surface flatness, clamp pressure, the presence of adhesives, inhomogeneity, and the thickness of the material all have a significant impact on the thermal resistance of the material. Therefore, thermal resistance takes into account more variables specific to the structure. Thermal resistance is usually expressed in units of m2 K / watt. SUMMARY OF THE INVENTION

[0027] One object of the present invention is to improve the thermal management function by conducting heat generated within a battery cell far away, for example, to a cooler, and to minimize heat propagation from cell to cell, from module to module, and from pack to vehicle. A thermal fin and a battery module are provided. The thermal fin is designed to be disposed between any battery pack sub-assemblies, such as between battery modules, between battery cells, or between battery packs, as disclosed below.

[0028] Accordingly, the present invention provides a thermal fin according to claim 1 and a battery device according to claim 11.

[0029] More specifically, a thermal fin for a battery device configured to prevent heat propagation between cells, between modules, and / or between a pack and a vehicle includes first and second contact units. The first contact unit (with high thermal conductivity) is in face-to-face contact with a first battery pack sub-assembly. Such a sub-assembly can be, for example, an individual battery cell, or a battery module including a plurality of cells, or a battery pack including a plurality of battery modules. The second contact unit can be in face-to-face contact with a second battery pack sub-assembly. A support unit (or insulator) is disposed adjacent to the first contact unit. The support unit can be sandwiched between the first contact unit and the second contact unit to create a thermally insulating space between the first contact unit and the second contact unit. The thermal fin extends in a plane and defines a height, a width, and a thickness. The in-plane thermal resistance is lower than the thermal resistance in a direction perpendicular to the plane, i.e., across the thickness of the fin, such that the fin provides a thermal management function and a thermal safety function for the battery device. The support unit includes a structure arranged such that an insulating gap (especially a fluid gap, preferably an air gap) is maintained between the first contact unit and the second contact unit. The gap forms an insulating layer that prevents heat transfer between cells.

[0030] The gaps are defined or predetermined and their design can be adapted to the shape requirements, size requirements, or performance requirements of the battery subassembly.

[0031] Such sandwiched structures provide low thermal resistance within the plane of the fins, but good thermal resistance in a direction perpendicular to the fin plane (across the fin thickness). The sandwiched structures allow individual cells to be cooled while insulating one cell from adjacent cells. Thus, less than 20% (even more specifically less than 10%, even more specifically less than 5%) of the heat is transferred from one battery pack subassembly to another. This arrangement also promotes a uniform temperature within the cells.

[0032] In another embodiment, the structure comprises a support plate sandwiched between a first spacer and a second spacer, thereby providing insulating gaps, in particular fluid gaps, on both sides of the plate. For example, the plate extends parallel to the first and / or second contact units. The fluid gaps on both sides of the support plate increase the thermal resistance.

[0033] In another embodiment, the insulating gap is a fluid gap and more specifically a void. Such voids can be easily implemented and are satisfactory.

[0034] In yet another embodiment, the first and / or second contact units (conductors) and the structure are made of two different materials. More specifically, the first and second contact units are made of a material having a high thermal conductivity, and the structure or support unit is made of a material having a low thermal conductivity. For example, the high thermal conductivity material is a material having a thermal conductivity in the range of 100 to 3000 W·m-1·K-1. Graphite or copper is a material having a high thermal conductivity. In contrast, the low thermal conductivity material is a material having a thermal conductivity of less than 400 W·m-1·K-1. Some metals, plastics, or glasses have a low thermal conductivity.

[0035] In another embodiment, the first and / or second contact units can be made from copper and / or aluminum, with or without graphite. In particular, the first and / or second contact units can be made from copper, or from copper adhered to graphite, or from aluminum adhered to graphite. The first and / or second contact units can also be made from alloy steel adhered to graphite.

[0036] In one embodiment, the structure is made of paper. Paper insulators are not expensive and have sufficient strength for the purposes of the present invention.

[0037] In one embodiment, a structure made of paper can be coupled to a contact unit made of graphite. In fact, graphite provides good flexibility.

[0038] In one embodiment, the structure is made of a mica-based material.

[0039] In one embodiment, the thickness of the fluid gap in cross-section is about 0.05 to 1 mm.

[0040] In one embodiment, the support structure has a lattice pattern. Using a lattice pattern enables a uniform thickness of the fluid gap.

[0041] In one embodiment, the structure is at least partially corrugated.

[0042] In one embodiment, the structure comprises at least one intermediate plate having a first surface and a second surface opposite the first surface, with a first plurality of spacers extending from the first surface and a second plurality of spacers extending from the second surface.

[0043] In one embodiment, the thermal fins have a total thickness of less than 10 mm, particularly between 0.5 and 2 mm, in a direction perpendicular to the fin plane.

[0044] The present invention also relates to a battery module comprising a plurality of electrically interconnected battery cells and the plurality of thermal fins described above, wherein each thermal fin is arranged in thermal communication with at least two of the plurality of battery cells or battery pack sub-assemblies, and first and second contact units are connected to a cooler.

[0045] In one embodiment, the thermal fins and the plurality of battery cells have a substantially planar structure such that an adjacent facing relationship is formed between one thermal fin and at least two of the plurality of battery cells.

[0046] In one embodiment, a first thermal fin comprises a first contact unit that contacts a first battery cell, a second thermal fin comprises a second first contact unit that contacts a second battery cell, and an expansion compensator is arranged between the two thermal fins.

[0047] In one embodiment, the first contact unit makes face-to-face contact with the first battery cell, and the second contact unit makes face-to-face contact with the second battery cell.

[0048] The present invention also relates to a support unit for a thermal fin comprising a structure arranged to establish an insulating gap, the structure comprising at least one intermediate plate having a first surface and a second surface opposite the first surface, a first plurality of spacers extending from the first surface, and a second plurality of spacers extending from the second surface.

[0049] The present invention and its advantages will be better understood from the following description given by way of example only and with reference to the accompanying drawings.

Brief Description of the Drawings

[0050]

Figure 1

Figures 2A - 2I

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 4C

Figure 5A

Figure 5B

Figure 5C

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0051] Embodiments of the present disclosure will be best understood by reference to the drawings. In the drawings, the same reference numerals indicate the same or similar elements. It will be readily understood that the components of the embodiments of the disclosure generally described herein and illustrated in the figures can be arranged and designed in a wide variety of different configurations. Accordingly, the following detailed description of embodiments of the systems and methods of the present disclosure is not intended to limit the scope of the claimed present disclosure, but merely represents possible embodiments of the present disclosure. In addition, unless otherwise specified, each step of the method need not necessarily be performed in any particular order, or even continuously, nor need each step be performed only once.

[0052] In some cases, well-known features, structures, or operations are not illustrated or described in detail. Further, the features, structures, or operations described can be combined in any suitable manner in one or more embodiments. It will also be readily understood that the components of the embodiments generally described herein and illustrated in the figures can be arranged and designed in a wide variety of different configurations.

[0053] Figure 1 shows an end view of a battery module 10 according to the prior art. The battery module 10 includes a plurality of battery cells 12. Cooling fins 14 are positioned between adjacent pairs of cells 12. Each cooling fin 14 has an L-shaped cross-section, with a first long surface in contact with a first battery cell and a second surface (base) narrower than the first surface in contact with a cooler 16. The cooler 16 may be passive (e.g., a radiating heat sink) or active (e.g., a heat exchanger with a gas or liquid flowing through it). Two L-shaped cooling fins 14 are positioned, for example, between two adjacent battery cells 12. The cooler 16 can be generally flat and can include several layers 18, 20, 22, 24. The first layer 18 can be, for example, a thermal pad, the second layer 20 can be a first cooling plate, the third layer 22 can be a fluid flow path for transporting a refrigerant, and the final layer 24 can be a second cooling plate. Each battery fin 14 is made of, for example, aluminum or other materials that have good thermal conductivity and transport heat from the battery cell it contacts to the cooler 16.

[0054] As described above, the cooling fins 14 of FIG. 1 perform a thermal management function by conducting excessive heat away from the cells 12, but do not perform the thermal safety function (as defined above). Heat transfer can occur between battery cells, and such inter-cell heat transfer can cause a "thermal runaway event" in adjacent cells. The term thermal runaway event refers to an uncontrollable temperature rise within a battery system. During a thermal runaway event, heat generation within the battery system or battery cell exceeds heat dissipation, thus causing a further temperature rise. Thermal runaway events can be caused by various conditions, including short circuits within the cell, improper use of the cell, physical abuse, manufacturing defects, or exposure of the cell to extreme external temperatures. To avoid such runaway events, a safety thermal function is required.

[0055] Figures 2A through 2I, 3A, 3B, 4, and 6 illustrate several embodiments of thermal fin 26 according to the present invention that provide both a thermal management function and a safety thermal function. Such thermal fin 26 is adapted to replace cooling fin 14 shown in FIG. 1.

[0056] As shown in FIGS. 2A through 2I, 3A, 3B, 4, and 6, the improved thermal fin 26 generally includes a first contact unit 28, a second contact unit 30, and a support unit 32 sandwiched between the first contact unit 28 and the second contact unit 30. The thermal fin 26 has a substantially planar geometry with a thickness that is much smaller than its height or length (width). For example, the ratio of height to thickness is between 25 and 1000. In this service, planar does not necessarily mean flat. The safety fins can be shaped to conform to the outer shape of the battery subassembly, which can be flat, cylindrical, or angular.

[0057] As shown in FIG. 3A, for example, the first contact unit 28 includes a substantially flat structure having a thickness t that is much smaller than the height H or length L. More specifically, the first contact unit 28 includes a first portion 34 adapted to contact the first battery cell 36 and a second portion 38 adapted to contact a cooler 40 (see the dotted line in FIG. 3A). The second portion 38 extends, for example, at a right angle to the first portion 34. The first contact unit 28 can generally be L-shaped. The first portion 34 is substantially planar and has a first surface 42 facing outward and adapted to contact the first battery cell 36 and a second surface 44 on the opposite side of the first surface and facing inward. The first portion 34 has, for example, a height of about 100 - 300 mm and a thickness of about 0.05 - 1 mm. The second portion 38 has a length and surface that are smaller than those of the first portion 34.

[0058] The second contact unit 30 is generally identical to the first contact unit 28 (and is arranged in a mirror-image geometry). The second contact unit 30 comprises a first portion 34 adapted to contact the second battery cell 37 and a second portion 38 adapted to contact the cooler 40. The second portion 38 extends, for example, at a right angle to the first portion 34. The second contact unit 30 can generally be L-shaped. The second portion 38 has a smaller length and a narrower surface than the first portion. The first portion 34 is substantially planar and has a first surface 42 facing outward and adapted to contact the second battery cell 37 and a second surface 44 facing inward and opposite to the first surface 42. The first portion 34 has, for example, a height of about 100 - 300 mm and a thickness of about 0.05 - 1 mm.

[0059] Both the first and second contact units 28, 30 are realized in a material having a high thermal conductivity. For example, the first or second contact unit 30, 28 can be made of graphite, or copper, or an aluminum alloy, or alloy steel, or some combination of those materials. More specifically, the contact units 28, 30 are made of copper or graphite. They enable the transport of heat from the first portion 34 to the cooler 40 and thus remove heat from within the battery module. Thus, the thermal conductivity within the fin plane formed by the first portion 34 is relatively high. The contact units transfer heat but do not absorb heat.

[0060] A support unit 32 is disposed between the first contact unit 28 and the second contact unit 30. The support unit 32 extends between the second surfaces of the first and second contact units 28, 30. The support unit 32 includes at least one material different from the materials of the first or second contact units 28, 30. The support unit 32 can be made of one or more materials having a low thermal conductivity. In any case, the support unit 32 as a whole has a high thermal resistance. For example, the support unit 32 can include a structure 50 made of metal, plastic, glass, paper, aluminum, mica, or alloy steel. More specifically, the support structure is made of mica or paper material. Mica and paper are lightweight materials that enable low thermal conductivity. More specifically, using these materials, a thermal conductivity of about 0.001 W / mK can be achieved. The shape or arrangement of the structure 50 is such that the support unit 32 has a higher thermal resistance than the thermal resistance of the contact units 28, 30. The support unit 32 can include, for example, a structure arranged to provide a fluid gap 52, such as a void, between the first contact unit 28 and the second contact unit 30. Generally, the support unit 32 can consist of the structure 50 and the void 52.

[0061] The first and second contact units 28, 30 generally extend over and are in contact with most of the facing surfaces of the battery cells 36, 37 and are designed to contact the cooler 40. Generally, the support unit 32 is not designed to contact the cooler 40, but is designed to extend entirely between the first contact unit 28 and the second contact unit 30, spatially separate the first contact unit 28 and the second contact unit 30, and thermally insulate them. The support unit 32 forms a thermal barrier.

[0062] The thermal fin 26 including the support unit 32 and the first and second contact units 28, 30 extends in the fin plane and has a fin length Lfin, a fin height Hfin, and a fin thickness t fin The thermal fin height Hfin and the thermal fin thickness tfin The ratio to is between 25 and 1000. The structure of the thermal fin 26 is generally planar and can also be flat, or can be shaped to conform to the outer shape of the battery cells 36, 37. Due to the insulating fluid gap created by the support unit and / or the different thermal conductivities of the different materials used for the contact units 28, 30 and the support unit 32, the thermal resistance within the fin plane is lower than the thermal resistance in the direction perpendicular to (across the thickness of) the fin plane. Constructed in such a way, the thermal fin 26 provides a thermal management function that removes heat and directs it to the coolers 16, 40, and a thermal safety function that insulates against heat propagation between adjacent cells 26, 37 within the battery module or between adjacent battery pack sub-assemblies.

[0063] Figure 3A shows the battery cells 36, 37 having a rectangular shape. However, as described above, the shape of the battery cell can be different. For example, the battery cell can have a cylindrical shape as shown in Figure 4. The dotted line in Figure 4 schematically represents a thermal fin whose shape conforms to the outer shape of the cylindrical battery cell. In other embodiments (not shown), the battery cell can also be a pouch cell.

[0064] The support unit 32 can have various designs or arrangements, as represented, for example, in Figures 2A through 2I, 3A, 3B, and 4.

[0065] In FIG. 2A, the support unit 32 includes a structure 50 and a void 52. The structure 50 includes a first plate 501 connected to the second surface 44 inside the first contact unit 28 and a second plate 502 connected to the second surface 44 inside the second contact unit 30. For example, the plates 501 and 502 extend over most of the second surface 44 of the contact unit 28 and are in face-to-face contact with the second surface 44. The plates 501 and 502 can be adhered to the second surface 44 of the contact units 28 and 30. A spacer structure 503 is positioned between the first plate 501 and the second plate 502. The spacer structure 503 has a corrugated (wavy) cross-section and forms a plurality of fluid gaps or voids 52 between the first plate 501 and the second plate 502. The corrugated spacer structure 503 and the first and second plates 501 and 502 can be made of the same material. The material has a low thermal conductivity and can be, for example, a structured metal, plastic, glass, paper, aluminum, or alloy steel. As alternative spacer structures, there can be fixed points, adhesives, parallelepipeds, bars (linear fixations), and grids, as will be further described below. The spacer structure can also be formed by sintered points or foam points. The spacer structure 503 can include various elements and can be formed from various parts that may or may not be connected. More specifically, the spacer structure 503 can include a first sub-structure on one side of the first plate and a second sub-structure on the other side of the first plate.

[0066] In FIG. 2B, the structure 50 of the support unit 32 is similar to the structure 50 of the support unit 32 in FIG. 2A, except that the first and second plates 501, 502 are not in face contact with the second surface 44. The first and second plates 501, 502 are fixed to the second surface 44 and spaced apart from the second surface 44 by fixing points 504 which can be, for example, sintered points or adhesive points. These fixing points 504 can be arranged to provide a further fluid gap or void between the contact units 28, 30 and the plates 501, 502. Alternatively, instead of the fixing points 54, linear fixings can also be provided. For example, a grid (see FIGS. 3A and 3B) can be provided between the plate and the contact unit.

[0067] As shown in FIG. 2C, the structure 50 can also be made from one plate 501 that extends between the second surfaces 44 of the first and second contact units 28, 30 and is fixed to the second surface 44 through the fixing points 504. These fixing points 504 can be, for example, sintered points or adhesive points. These fixing points 504 are arranged to provide a fluid gap or void 52 between the contact units 28, 30 and the plate 501. Alternatively, instead of the fixing points, linear fixing can also be performed. For example, a grid is provided between the plate and the contact unit.

[0068] In FIG. 2D, the structure 50 is a hollow parallelepiped in which the first and second longitudinal plates 501, 502 are in contact with the second surfaces 44 of the first and second contact units 28, 30, and the lateral face 506 connects the first longitudinal face 501 and the second longitudinal face 502. The hollow space forms the fluid gap 52.

[0069] In FIG. 2E, the structure 50 is generally similar to the parallelepiped of FIG. 2D, except that the first and second longitudinal plates 501, 502 are not in face-to-face contact with the second surface 44, but are fixed to the second surface through fixing points 504 which can be sintered points or adhesive points for example. These fixing points 504 can be arranged to provide an additional fluid gap or void between the contact unit and the parallelepiped. Alternatively, instead of fixing points, linear fixing can also be carried out. For example, a grid can be provided between the plate and the contact unit.

[0070] The structure 50 of FIG. 2F has a ladder shape in which the first plate 501 is in face-to-face contact with the first contact unit 28 and the second plate 502 is in face-to-face contact with the second contact unit 30. The first and second plates 501, 502 are connected together at intervals by a plurality of bars 508 perpendicular to the first and second plates 501, 502. A fluid gap 52 is provided between two adjacent bars and between the first plate and the second plate.

[0071] In FIG. 2G, the structure 50 is generally similar to the structure 50 of FIG. 2F, except that the first and second plates 501, 502 are not in face-to-face contact with the second surface 44. The first and second plates 501, 502 are fixed to and spaced from the second surface 44 through fixing points 504 which can be sintered points or adhesive points for example. These fixing points 504 can be arranged to provide an additional fluid gap or void 52 between the contact units 28, 30 and the plates 501, 502. Alternatively, instead of fixing points, fixing using bars 508, linear elements, or a grid can also be carried out.

[0072] In FIGS. 2H and 2I, the structure 50 includes a plurality of plates 501, 502, 511, 512 that extend parallel to each other and are connected to each other by bars 508. The bars 508 can extend perpendicular to the plates 501, 502. For example, four plates are provided. The outermost plates 501, 502 are connected to the contact units 28, 30. In FIG. 2H, the outermost plates 501, 502 are in face-to-face contact with the contact units 28, 30. In FIG. 2I, linear or dot-shaped fixing portions 504 are provided.

[0073] In FIG. 6, the support unit 32 includes a structure made from three plates and a spacer structure 503 such that a plurality of spacers are arranged on each side of each plate. The spacers can be stacked vertically or arranged alternately as shown in FIG. 6.

[0074] As can be seen in FIG. 7, the spacer structure 503 can consist of a plurality of strips that extend longitudinally in the width of the first plate 501. More specifically, the spacers can be strips evenly arranged on the first plate 501. Each strip can have a width between 1 and 5 mm, more specifically between 1 mm and 1.5 mm. To ensure the rigidity of the support unit and the presence of the gap 52 generated by the spacers, the strips can be arranged at a distance d of at least 5 mm from each other.

[0075] FIG. 8 shows an embodiment of the support structure 32 with the first plate 501. The first plate has a first surface and a second surface opposite the first surface. A first plurality of spacers are arranged on the first surface, and a second plurality of spacers are arranged on the second surface. The support structure 32 can exhibit a width between 50 and 300 mm and a length L between 50 and 1000 mm.

[0076] Figure 3A shows another embodiment of the thermal fin 26 in an exploded assembly view. The first battery cell 36 and the second battery cell 37 are represented in dotted lines. The cooler 40 is also represented in dotted lines. A thermal fin 26 with first and second contact units 28, 30 is disposed between the first battery cell 36 and the second battery cell 37. Each contact unit 28, 30 has an L-shape in which a first portion 34 extends along the surfaces of the battery cells 36, 37, and a second portion 38 smaller than the first portion 34 faces the cooler 40 and is in direct or indirect contact with the cooler 40. Both the first and second contact units 28, 30 are made of the same material having high thermal conductivity. The material can be copper or an aluminum alloy.

[0077] In an embodiment shown in FIG. 3B, which is otherwise similar to the embodiment of FIG. 3A, the first and second contact units 28, 30 are each made of two different materials. For example, a graphite plate 60 is adhered to a copper plate, or an aluminum alloy, or an alloy steel 62. This layered structure enables better flexibility. In fact, graphite is more elastic or flexible than copper or aluminum, and thus the overall manufacturing, handling, or use of the system becomes easier. The contact height H corresponds to the thermal fin height Hfin. The first portion 34 of the contact units 28, 30 has a contact thickness t (see FIG. 3A), which can be about 0.05 to 1 mm. The first portion 34 of the contact units 28, 30 has a contact length L, which can be about 100 to 1000 mm.

[0078] In FIGS. 3A and 3B, a support unit 32 extends between two contact units 28, 30 and includes a structure 50. The structure 50 includes a plate 501 sandwiched between a first grid 64 and a second grid 66. Depending on the plate material, the plate 501 can also be in contact with the cooler 40 (when the plate material has, for example, a high thermal conductivity), or can be located away from the cooler (for example, in the case of a plate material having a lower thermal conductivity). The grids 64, 66 are made of, for example, paper. The holes 70 open in the grids form a fluid gap (void) 52 between the contact units and the plate 501.

[0079] The plate 501 has a thickness t of about 0.02 to 1 mm p and. The plate 501 is made of, for example, an aluminum alloy, or alloy steel, or paper. As described above, the plate 501 may or may not be in contact with the cooler 40 depending on the thermal conductivity of the plate material. The dimensions (length Lp and height Hp) of the plate 501 are generally the same as the dimensions of the first portions 34 of the contact units 28, 30.

[0080] Each grid has a thickness t of about 0.02 to 1.0 mm that allows for a void 52 of approximately the same thickness grid and. The grids 64, 66 can be adhered to the plate 501 or the contact units 28, 30.

[0081] The thermal fins 26 thus formed by the contact units 28, 30, the grids 64, 66, and the plate 501 have a total fin thickness t in cross-section fin which is in the range of 0.5 to 10 mm, and more specifically in the range of 0.5 to 4 mm. For example, the thermal fins between battery modules have a greater thickness than the thermal fins between cells. Thus, the first range may correspond to the thermal fins between battery modules, in which case the second range corresponds to the thermal fins between battery cells. In particular, a thickness between 0.5 and 2 mm can be provided for the thermal fins between cells.

[0082] A battery sub - assembly, and for example a battery module, can also be surrounded by one or more thermal fins, as described below, wherein a first contact unit is in face - to - face contact with, for example, a certain battery module, and wherein a second contact unit is on the contact surface with another battery module.

[0083] For illustrative purposes, FIGS. 4A to 4C schematically show a battery cell or a battery module together with thermal fins 26. In these figures, the center of the arrangement (the part extending within the first contact unit 28) can be a battery cell 36, or a battery module M comprising a plurality of battery cells. The thermal fins 26 comprise a structure 50 arranged to form a first contact unit 28, a second contact unit 30, and a fluid gap 52. The structure 50 comprises a first plate 501, a second plate 502, and a spacer structure 503. In these figures, a specific structure of the thermal fins 26 is represented by way of example. For example, any thermal fin arrangement disclosed above can be used.

[0084] As can be seen in these figures, one thermal fin 26 can surround the cell (especially in the case of a cylindrical cell or a rectangular cell having an elliptical cross - section), or several thermal fins 26 can be arranged adjacent to each other so as to surround, for example, a battery module.

[0085] FIG. 4A schematically shows a rectangular battery module M or a battery cell 36 having a parallelepiped shape. FIG. 4A is a side view. The thermal fin 26 surrounds the parallelepiped shape (except from the bottom). In FIG. 4B, the cross - section of the rectangular battery module M or the battery cell 36 has an elliptical shape. FIG. 4C shows a cylindrical battery module M or a battery cell C. The thermal fin 26 surrounds the entire perimeter of the module M or the cell.

[0086] Figures 5A through 5C also schematically show the battery cell 36 or the battery module M together with the thermal fin 26. In these figures, the thermal fin 26 does not include a second contact unit. The thermal fin includes, in these embodiments, only one first contact unit 28 and a support unit 32. The support unit 32 includes a structure 50 that forms a void 52. The structure 50 represented herein includes a first plate 501 that surrounds the first contact unit 28 and is in face-to-face contact with the first contact unit 28, a spacer structure 503, and a second plate 502 that surrounds the spacer structure 503. FIG. 5A is a schematic side view, and thus, the module M or the cell 36 (the rectangular battery module M or the battery cell 36 having a parallelepiped shape) is surrounded only on three sides (the fourth side is the bottom). FIGS. 5B and 5C are schematic cross-sectional views showing the state in which the thermal fin surrounds the battery module M or the battery cell 36.

[0087] As determined above, this thermal fin 26 can include only one contact unit 28 that constitutes the first contact unit, and a support structure. Between two thermal fins of such a design, an expansion compensator 72 can be arranged as shown in FIG. 9. The expansion compensator 72 can be a plastic expansion compensator or a metal expansion compensator. The expansion compensator 72 forms a compensation system for the expansion of the electrochemical cells that make up the battery. During the charging of a battery cell, for example, a lithium-ion type battery cell, the casing of the battery cell expands. In the case of a cell in a rectangular form (also called a prismatic cell), the expansion basically occurs on two opposite lateral planar surfaces that are the largest surfaces of the casing. This expansion amplifies as the state of charge of the battery cell approaches a fully charged state. Since the cells are joined to each other front and back within the housing and the thickness of each cell increases, a significant increase in the total length of the battery is also seen as a result of the addition of the increased thicknesses of the cells. The housing is generally made of a rigid material and the gap between the cell and the wall of the housing is limited, so the expansion of the cell exposes the wall of the housing to compressive forces, which may cause irreversible deformation of the housing or premature aging of the cell, or even damage to the battery. Therefore, the expansion compensator 72 is used to prevent the housing from deforming under the influence of the expansion of the cell during charging of the cell.

[0088] The expansion compensator can be made entirely of a plastic material and can include a flat body and a plurality of ribs protruding from the flat body towards the first and / or second battery cells. In another embodiment, the expansion compensator 72 can be made at least partially of a metal with a spring carrier.

[0089] Due to the overall structure of the thermal fins, horizontal high thermal resistance (low thermal conductivity) (between two adjacent cells 36, 37 or between two adjacent battery sub-assemblies) and low thermal resistance (high thermal conductivity) along the length and width of the contact units 28, 30 for heat conduction to the cooler 40 are enabled. Therefore, a cooling system with a plurality of thermal fins 26 is completely passive, lightweight, and uncomplicated.

[0090] Although specific examples have been shown and described herein, various alternative implementations and / or equivalent implementations can be used in place of the specific examples shown and described without departing from the scope of the present disclosure. This application encompasses any adaptations or variations of the specific examples discussed herein.

Description of Reference Numerals

[0091] 10 Battery module 12 Battery cell 14 Cooling fin 16 Cooler 18 First layer 20 Second layer 22 Third layer 24 Final layer 26 Heat insulator 28 First contact unit 30 Second contact unit 32 Support unit 34 First part 36 First battery cell 38 Second part 40 Cooler 42 First surface 44 Second surface 50 Structure 501, 502, 511, 512 Plates 504 Fixed point 506 Lateral surface 508 Bar 510 Bump 52 Fluid gap 70 Hole 72 Expansion compensator H height contact unit L length contact unit Hp height plate Lp length plate Lfin fin length Hfin fin height t contact unit thickness t p plate thickness t grid grid thickness t fin fin / total thickness

Claims

1. A thermal fin (26) for a battery device, configured to prevent heat transfer between battery pack sub-assemblies, comprising: a first contact unit (28) adapted to face-contact a first battery pack sub-assembly (12); a support unit (32) adjacent to the first contact unit (28); and the thermal fin (26) extends in a fin plane, has a fin length (Hfin) in a cross-section along a longitudinal axis, and a fin thickness (t fin ) where the fin thickness is smaller than the fin length, and a thermal resistance in the fin plane (X, Y) is lower than a thermal resistance in a direction perpendicular to the fin plane, whereby the thermal fin realizes a thermal management function and a thermal safety function of the battery device; the contact unit is made of a first material, the support unit is made of a second material, and the first material is different from the second material; the support unit (32) comprises a structure (50) arranged to establish an insulating gap (52) between the first contact unit and a second contact unit (28, 30); thermal fin (26).

2. Further comprising a second contact unit (30) adapted to face-contact a second battery pack sub-assembly (12), wherein the support unit (32) is sandwiched between the first contact unit and the second contact unit (28, 30), the thermal fin (26) according to claim 1.

3. The structure (50) comprises a plate (501) sandwiched between spacer structures (503), whereby insulating gaps (52) are provided on both sides of the plate (501), the thermal fin (26) according to claim 1 or 2.

4. The thermal fin (26) according to any one of claims 1 to 3, wherein the insulating gap (52) is a fluid gap, preferably an air gap.

5. The thermal fin (26) according to any one of claims 1 to 4, wherein one of the first and second contact units (28, 30) and the other structure (50) are made of two different materials.

6. The thermal fin (26) according to any one of claims 1 to 5, wherein the first and / or the second contact unit contains copper and / or aluminum and / or graphite.

7. The thermal fin (26) according to any one of claims 1 to 6, wherein the structure (50) is made of a paper material or a mica-based material.

8. The thermal fin (26) according to any one of claims 1 to 7, wherein the thickness of the fluid gap in cross-section is about 0.05 to 1 mm.

9. The thermal fin (26) according to any one of claims 1 to 9, wherein the structure (50) has a lattice pattern.

10. The thermal fin (26) according to any one of claims 1 to 9, wherein the structure (50) includes at least one intermediate plate having a first surface and a second surface opposite to the first surface, and a first plurality of spacers extend from the first surface and a second plurality of spacers extend from the second surface.

11. The thermal fin (26) according to any one of claims 1 to 10, wherein the thermal fin has a total thickness of less than 10 mm, particularly between 0.5 and 4 mm, in a direction perpendicular to the fin plane.

12. A battery module comprising a plurality of electrically interconnected battery cells and a plurality of thermal fins according to any one of claims 1, wherein each thermal fin is arranged in thermal communication with at least one of the plurality of battery cells, and the first contact unit is connected to a cooler.

13. The battery module according to claim 12, wherein the first thermal fin comprises a first contact unit that contacts the first battery cell, the second thermal fin comprises a second first contact unit that contacts the second battery cell, and an expansion compensator is arranged between the two thermal fins.

14. A support unit (32) for a thermal fin (26) according to any one of claims 1 to 11, comprising a structure (50) arranged to establish an insulating gap (52), the structure (50) comprising at least one intermediate plate having a first surface and a second surface opposite the first surface, a first plurality of spacers extending from the first surface, and a second plurality of spacers extending from the second surface.

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