THERMALLY OPTIMIZED BATTERY PACK

Abstract

The present invention pertains to a battery pack. The battery pack includes a cell holder case (200) comprising a first cooling plates (202a-202n) and a second cooling plates (204a-204n), each positioned upright and spaced by specific offset, particularly intersecting each other in a grid configuration with first cooling plates (202a-202n) extending in the rows and the second cooling plates (204a-204n) extending in the columns, forming grid cells (206a-206n). Each grid cell (206a-206n) has an integral tubular slot (208a-208n) to hold a battery cell. The inner wall is provided with at least one layer of thermally conductive and electrically insulative material, which remains solid throughout thermal cycling, resulting in improved thermal dissipation, thereby enhancing the performance of the battery pack. FIG. 2

Specification

Description:FIELD OF INVENTION
[0001] Embodiments of the present disclosure relate generally to battery packs, more particularly to battery packs with integral thermal management features facilitating improved cooling of cells within the battery packs, a method thereof and an electric vehicle powered by such battery packs.
BACKGROUND
[0002] Cordless devices that utilize rechargeable cells are widely found in the market. These cells are incorporated into a diverse array of electronic products, ranging from portable computers to power tools. Since many of these devices require multiple battery cells, they are usually assembled into a battery pack, which supplies power when connected. After the battery pack is exhausted, it can be recharged using a dedicated charger. Among the various types of rechargeable cells, lithium-ion cells offer the highest energy density relative to their volume and are prevalent in use for the same reason. However, lithium-ion cells are susceptible to ohmic loss, or resistive loss, which refers to the energy dissipated as heat due to the internal resistance encountered by the electric current flowing through the cells. Furthermore, cells often exhibit anisotropic thermal conductivity i.e., the higher in-plane conductivity enables effective heat conduction across the layers, while lower through-thickness conductivity can lead to localized hot spots near the terminals, where heat accumulates. The localized hot spots so developed not only impacts the performance and capacity of battery but significantly accelerates the degradation of the same, ultimately, shortening the life span of battery packs and increasing the risk of safety hazards, including thermal runway.
[0003] Conventionally, various techniques have been developed to provide heat dissipation within the battery pack. One common approach is the incorporation of orifices exposing the terminals of battery cells to the airflow. However, while orifices improve ventilation, this approach is only marginally effective, for example, the cells located in the middle of the battery pack often experience higher current density during charging and discharging and these cells are often isolated from airflow owing to the immediate neighbor cells, which limits their exposure to cooling effects, this further limits the design of the battery pack, eventually, taking up valuable space.
[0004] In other approaches, in addition to vent holes, external cooling components such as phase change materials (PCMs) or multiple tubes having channels for fluid transfer, coupled to exterior walls of the cells to conduct heat exchange are employed. However, addition of such external components considerably increases the space occupied by the cells and in turn the battery pack. Thus, to accommodate battery pack equipped with such external components, modifications in structure of the battery pack may be required which may increase complexity in designing and manufacturing of the same. Also, such additional components may increase the overall weight of the battery pack which is undesirable for portable devices or automobiles powered by battery pack.
[0005] Further, such external components may increase challenges in structurally arranging the cells in the battery pack as the externally attached components may obstruct in arranging the cells together in a compact manner and the cells may thus have to be arranged at some distance from each other. The battery pack may thus require more space, leading to wastage of space between the cells in the battery pack. Further, as the external channels or PCMs coupled to external walls of the cell must conduct a cooling effect over a thickness of a casing of the battery to maintain temperature of the battery, the exchange of heat may require more time and energy.
[0006] Thus, there is a pressing need to provide an improved battery pack that combines efficient heat dissipation with structural simplicity and safety, particularly taking into consideration the undesirable localized hot spots developed within the battery pack.
BRIEF DESCRIPTION
[0007] In accordance with an embodiment of the present disclosure, a battery pack is provided. The battery pack includes a cell holder case formed by a plurality of cooling plates. Particularly, the cell holder case includes a plurality of first cooling plates and a plurality of second cooling plates, each positioned upright and spaced apart by a definite first offset. The cooling plates intersect to form a grid configuration of rows and columns, with the plurality of first cooling plates extending along the rows and the plurality of second cooling plates extending along the columns, thereby creating a plurality of grid cells. Each grid cell features a tubular slot that is integrally formed therein to accommodate a respective battery cell, where the outer wall of each tubular slot abuts at least three walls of the corresponding grid cell. Additionally, the inner wall of each tubular slot is provided with at least one layer of thermally conductive and electrically insulative material, which substantially circumvents the battery cell and remains solid throughout thermal cycling. The battery pack further includes a cell tray. The cell tray features a plurality of channels arranged in a grid pattern, defining various accommodating spaces. Each channel is affixed with a thermal pad using a thermally conductive adhesive.
[0008] In accordance with another embodiment of the present disclosure, a method of fabricating a battery pack is provided. The method includes forming a cell holder case by positioning a plurality of first cooling plates upright with each cooling plate at a first offset and a plurality of second cooling plates upright with each cooling plate at the first offset such that the plurality of first cooling plates and the plurality of second cooling plates intersect each other to form a grid configuration of rows and columns with the plurality of first cooling plates extending along the rows and the plurality of second cooling plates extending along the columns, thereby defining a plurality of grid cells, wherein each grid cell comprises a tubular slot integrally formed therein to insert a respective battery cell of the plurality of battery cells such that outer wall of each tubular slot abuts at least three walls of the corresponding grid cell. Further, the method includes providing at least one layer of thermally conductive and electrically insulative material in inner wall of the tubular slot substantially circumventing the battery cell, wherein the material remains solid throughout thermal cycling. Furthermore, the method includes providing a cell tray with a plurality of channels arranged in a grid pattern defining a plurality of accommodating spaces and affixing a respective thermal pad to each channel of the plurality of channels using a thermally conductive adhesive.
[0009] In accordance with yet another embodiment of the present disclosure, an electric vehicle is provided. The electric vehicle includes a battery pack which includes a cell holder case formed by a plurality of cooling plates. Particularly, the cell holder case includes a plurality of first cooling plates and a plurality of second cooling plates, each positioned upright and spaced apart by a definite first offset. These cooling plates intersect to form a grid configuration of rows and columns, with the plurality of first cooling plates extending along the rows and the plurality of second cooling plates extending along the columns, thereby creating a plurality of grid cells. Each grid cell features a tubular slot that is integrally formed therein to accommodate a respective battery cell, where the outer wall of each tubular slot abuts at least three walls of the corresponding grid cell. Additionally, the inner wall of each tubular slot is provided with at least one layer of thermally conductive and electrically insulative material, which substantially circumvents the battery cell and remains solid throughout the thermal cycling. The battery pack further includes a cell tray. The cell tray features a plurality of channels arranged in a grid pattern, defining various accommodating spaces. Each channel is affixed with a thermal pad using a thermally conductive adhesive.
[0010] To further clarify the advantages and features of the present disclosure, a more particular description of the disclosure will follow by reference to specific embodiments thereof, which are illustrated in the appended figures. It is to be appreciated that these figures depict only typical embodiments of the disclosure and are therefore not to be considered limiting in scope. The disclosure will be described and explained with additional specificity and detail with the appended figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The disclosure will be described and explained with additional specificity and detail with the accompanying figures in which:
[0012] FIG. 1 illustrates a perspective view and partial inside view of a battery pack in accordance with an embodiment of the present disclosure;
[0013] FIG. 2 illustrates a perspective view of a cell holder case, provided in the battery pack as illustrated in FIG. 1, in accordance with an embodiment of the present disclosure;
[0014] FIG. 3 illustrates a detailed perspective view of a cell holder case depicted in FIG. 2 in accordance with an embodiment of the present disclosure;
[0015] FIG. 4 illustrates a perspective view of a cell tray canopying a cell holder case (200, 300 shown in FIGS. 2 and 3 respectively) in accordance with an embodiment of the present disclosure;
[0016] FIG. 5 illustrates an inside view of a battery pack when multiple battery modules are stacked to form the battery pack of FIG. 1 in accordance with an embodiment of the present disclosure;
[0017] FIG. 6a-6c illustrates temperature variation across a battery pack during thermal cycling of FIG. 1 in accordance with an embodiment of the present disclosure;
[0018] FIG. 7a-7b illustrates a graph showing the temperature variation of battery cells and cell trays during thermal cycling of FIG. 1 in accordance with an embodiment of the present disclosure; and
[0019] FIG. 8 is a flow chart representing the steps involved in a method of fabricating a battery pack in accordance with an embodiment of the present disclosure.
[0020] Further, those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the figures by conventional symbols, and the figures may show only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the figures with details that will be readily apparent to those skilled in the art having the benefit of the description herein.
DETAILED DESCRIPTION
[0021] For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiment illustrated in the figures and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Such alterations and further modifications in the illustrated system, and such further applications of the principles of the disclosure as would normally occur to those skilled in the art are to be construed as being within the scope of the present disclosure.
[0022] The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such a process or method. Similarly, one or more devices or subsystems or elements or structures or components preceded by "comprises... a" does not, without more constraints, preclude the existence of other devices, sub-systems, elements, structures, components, additional devices, additional sub-systems, additional elements, additional structures or additional components. Appearances of the phrase "in an embodiment", "in another embodiment" and similar language throughout this specification may, but not necessarily do, all refer to the same embodiment.
[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs. The system, methods, and examples provided herein are only illustrative and not intended to be limiting.
[0024] In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings. The singular forms "a", "an", and "the" include plural references unless the context clearly dictates otherwise.
[0025] In accordance with an embodiment of the present disclosure, a battery pack is provided. The battery pack includes a cell holder case formed by a plurality of cooling plates. Particularly, the cell holder case includes a plurality of first cooling plates and a plurality of second cooling plates, each positioned upright and spaced apart by a definite first offset. The cooling plates intersect to form a grid configuration of rows and columns, with the plurality of first cooling plates extending along the rows and the plurality of second cooling plates extending along the columns, thereby creating a plurality of grid cells. Each grid cell features a tubular slot that is integrally formed therein to accommodate a respective battery cell, where the outer wall of each tubular slot abuts at least three walls of the corresponding grid cell. Additionally, the inner wall of each tubular slot is provided with at least one layer of thermally conductive and electrically insulative material, which substantially circumvents the battery cell and remains solid throughout thermal cycling. The battery pack further includes a cell tray. The cell tray features a plurality of channels arranged in a grid pattern, defining various accommodating spaces. Each channel is affixed with a thermal pad using a thermally conductive adhesive.
[0026] FIG. 1 illustrates a perspective view and partial inside view of a battery pack (100) in accordance with an embodiment of the present disclosure. The battery pack (100) shown in FIG. 1 is rectangular in shape, however, other shapes are also possible to optimize space utilization, thermal cooling and weight distribution. The shape of the battery pack housing may vary without deviating from the scope of the present subject matter. The battery pack (100) comprises an enclosure. As shown therein, the enclosure may be formed by multiple walls - an upper wall (102), a bottom wall (108) opposite to the upper wall (102), a first lateral wall (104), a second lateral wall (106) opposite to the first lateral wall (102), with two other walls (not shown) on the front and back defining the height and width of the enclosure with all the walls coupled with the other at their edges. It may be noted here that the enclosure may be formed by coupling the walls or as an integral unit or a single unit such as a single extrusion or bent metal sheet, contoured as walls of the enclosure, and any number of walls may be formed as required for compact cell packing or to enhance the structural stability. The enclosure may be made from aluminum, aluminum composite, or stainless steel, depending on the design requirements. The enclosure houses the various components of the battery pack, for example, as is commonly known, the battery pack (100) may comprise components, but not limited to BMS module, alternatively, known as battery management unit (not shown in the figure), sensors (not shown in the figure), in addition to battery modules (not shown in the figure) stacked up by connecting battery cells in series or parallel configurations to achieve the required voltage and capacity. In an example, to facilitate the placement of components within the enclosure and to enable repairs of any malfunctioning components, the enclosure may feature built in access points (not shown) or integral mechanisms at the coupling portions of the walls, allowing for opening of the battery pack, ensuring ease of maintenance.
[0027] FIG. 2 illustrates a perspective view of a cell holder case (200), provided in the battery pack (100) as illustrated in FIG. 1, in accordance with an embodiment of the present disclosure. Referring to FIG. 2, the cell holder case (200) is formed by a plurality of first cooling plates (202a-202n) positioned upright, each spaced apart by a first offset and a plurality of second cooling plates (204a-204n) positioned upright, each spaced apart by the first offset such that the plurality of first cooling plates (202a-202n) and the plurality of second cooling plates (204a-204n) intersect each other forming a grid configuration of rows and columns with the plurality of first cooling plates (202a-202n) extending along the rows and the plurality of second cooling plates (204a-204n) extending along the columns, thereby defining a plurality of grid cells (206a-206n), where each grid cell of the plurality of grid cells (206a-206n) comprises a corresponding tubular slot (208a-208n) integrally formed therein to insert a respective battery cell of the plurality of battery cells (not shown in this figure) such that outer wall of each tubular slot (208a-208n) abuts at least three walls of the corresponding grid cell (206a-206n). In particular, the tubular slots integrally formed at ends of grid configuration may abut three walls of the grid cells and neighboring tubular slots within the grid configuration may adhere to four walls of the grid cells in correspondence.
[0028] As further depicted in FIGS. 1-2, the plurality of first cooling plates (202a-202n), each comprise a first end (202a'-202n') emanating from the grid configuration, where the first end (202a'-202n') is in thermal contact with a first lateral wall (104 as shown in FIG. 1) of an enclosure of the battery pack (100 shown in FIG. 1) and a second end (202a''-202n'') emanating from the grid configuration, where the second end (202a''-202n'') is in thermal contact with a second lateral wall (106) of the enclosure of the battery pack. It may be noted here for clarity that the first end (202a'-202n') is in thermal contact with a first lateral wall (104 as shown in FIG. 1) of an enclosure of the battery pack (100 shown in FIG. 1) is intended to denote that the first end (202a'-202n') is in thermal contact with inner surface of the first lateral wall (104 as shown in FIG. 1) of the enclosure of the battery pack (100 shown in FIG. 1) rather than exterior surface of the first lateral wall (104). Likewise, a second end (202a''-202n'') emanating from the grid configuration, where the second end (202a''-202n'') is in thermal contact with a second lateral wall (106) of the enclosure of the battery pack) is intended to denote that the second end (202a''-202n'') is in thermal contact with inner surface of the second lateral wall (106 as shown in FIG. 1) of the enclosure of the battery pack (100 shown in FIG. 1) rather than exterior surface of the second lateral wall (106).
[0029] Further, thermal contact may be established by using any good thermally conductive adhesive which may exist as semi-solid, or gel and may solidify after the application. For example, the thermally conductive adhesive material may be a thermally conductive resin which may include but is not limited to a urethane-based material, a silicon-based material, or an acrylic-based material. The thermally conductive adhesive not only enhances the heat dissipation of the battery cells to the enclosure (102) via first ends and second ends of the first cooling plates (202a-202n) but also secures them in place.
[0030] It may be noted here that the dimensions of the plurality of first cooling plates (202a-202n), the plurality of second cooling plates (204a-204n) and the plurality of tubular slots (208a-208n) may be comparable to achieve thermal optimization considering localized hot spots. In another example, the dimensions of the plurality of battery cells may be taken into consideration and the dimensions of the plurality of tubular slots may be provided in accordance with the same to achieve snug fit of the battery cells. Additionally, in an example, the thermally conductive adhesive used to establish thermal contact between the ends of the cooling plates as elucidated in the corresponding description of FIG. 2 may be applied to external surface of the battery cells before they are placed into the respective tubular slots for securing them firmly in position through the adhesive contact with the respective at least one layer provided in the respective tubular slots. In another example, the thermally conductive adhesive used to fix the battery cells in the respective tubular slots may be different from the thermally conductive adhesive used to establish thermal contact between the ends of the cooling plates as elucidated in the corresponding description of FIG. 2.
[0031] Furthermore, in an example, the plurality of first cooling plates (202a-202n), the plurality of second cooling plates (204a-204n) and the plurality of tubular slots (208a-208n) may be made from aluminum, however, to achieve uniform distribution of heat and structural strength, any other metal or combination of metals forming an alloy exhibiting relatively good thermal conductivity and electric insulation may be used.
[0032] FIG. 3 illustrates a detailed perspective view of a cell holder case (300) in accordance with an embodiment of the present disclosure. Referring to FIG. 3, the cell holder case (300) (shown as 200 in FIG. 2) is formed by a plurality of first cooling plates (302a-302n) positioned upright, each spaced apart by a first offset and a plurality of second cooling plates (304a-204n) positioned upright, each spaced apart by the first offset such that the plurality of first cooling plates (302a-302n) and the plurality of second cooling plates (304a-304n) intersect each other forming a grid configuration of rows and columns with the plurality of first cooling plates (302a-302n) extending along the rows and the plurality of second cooling plates (304a-304n) extending along the columns, thereby defining a plurality of grid cells where each grid cell of the plurality of grid cells comprises a corresponding tubular slot (308a-308n) integrally formed therein to insert a respective battery cell of the plurality of battery cells (312a-312n) such that outer wall of each tubular slot (308a-308n) abuts at least three walls of the corresponding grid cell.
[0033] Further, as shown therein, the inner wall of each tubular slot (308a-308n) is provided with at least one layer (310a-310n) of thermally conductive and electrically insulative material substantially circumventing the corresponding battery cell of the plurality of battery cells (312a-312n), where the material remains solid throughout thermal cycling - repeated process of heating and cooling that occurs during charging, discharging, and operation of the battery pack. It is imperative to note here that the thickness of the at least one layer (310a-310n) is inversely correlated with the rate at which the heat transfer takes place from the battery cells to the enclosure of the battery pack. Therefore, the thickness of at least one layer (310a-310n) may be calibrated, taking into consideration the specific thermal resistance requirements necessary to optimize heat dissipation. In one example, the thickness of the at least one layer (310a-310n) may preferably be provided in the range of 0.5-2mm (millimeter). The thermally conductive and electrically insulative material comprises a uniform mixture of graphene and a composite material, commonly known as composite graphene mixed in a predetermined ratio (graphene to composite material), preferably, in the ratio of 1:10 or 1:25 and the composite material include any one or combination of polychloroprene, butyl rubber, polyisoprene rubber, styrene Butadiene, plastic ABS (acrylonitrile butadiene styrene), PC (poly carbonate) , FR (fiber-reinforced polymer), polyamide, polycarbonate, boron nitride. In an example, preferably, graphene may be mixed uniformly with polychloroprene, for example, mixing graphene and polychloroprene uniformly in the ratio 1:25, the observed thermal conductivity is 108.7 Wm-1k-1 and specific heat at constant pressure is 2181.82 Jkg-1℃-1 and density is 1404 kgm-3. Similarly, mixing graphene and polychloroprene uniformly in the ratio 1:10, the observed thermal conductivity is 163.64 Wm-1k-1 and specific heat at constant pressure is 2136 Jkg-1℃-1 and density is 1395 kgm-3. In another example, graphene may be uniformly mixed with composite material formed from polychloroprene and boron nitride, in the ratio of 1:10.
[0034] In another example, industrial graphene or graphene oxide may also be used in the place of composite graphene.
[0035] FIG. 4 illustrates a perspective view of a cell tray (402a, 402b) canopying a cell holder case (200, 300 shown in FIGS. 2 and 3 respectively) in accordance with an embodiment of the present disclosure. In one example, the cell tray (402a, 402b) may be made of the same material disposed as a layer (310a-310n as shown in FIG. 3) in the tubular slots. In another example, preferably, the cell tray (402a, 402b) may be made from uniform mixture of graphene and composite material comprising ABS (acrylonitrile butadiene styrene) and boron nitride, in the ratio of 1:10. The cell tray (402a, 402b) comprises a plurality of channels (not shown in the figure) arranged in a grid pattern defining a plurality of accommodating spaces (S), wherein each channel is affixed with a thermal pad (404a-404n, 406a-406n) using a thermally conductive adhesive. In an example, the thermally conductive adhesive may be same as the adhesive used to establish thermal contact between the ends emanating from the cooling plates to the walls of enclosure as elucidated in the description corresponding to FIG. 2 or different. The cell tray (402a, 402b) comprises a plurality of recesses (408a-408n), each formed in one of the accommodating spaces (S) and aligned with a corresponding battery cell to allow a terminal of the corresponding battery cell to emanate from the recess (408a-408n). It may be noted here that the cell tray (402a) is detachably placed intermediate to the cell holder case (200, 300 shown in FIG. 2 and 3 respectively) and the enclosure such that the plurality of channels formed on the cell tray (402a) face the enclosure. In another example, the cell tray (402a) is disposed intermediate to the cell holder case (200, 300 shown in FIGS. 2 and 3) and the enclosure such that the plurality of channels formed on the cell tray (402a) face the enclosure using any thermally conductive adhesive to establish a stronger fixation. Similarly, the cell tray (402b) may be used to place the cell holder case (200, 300 shown in FIGS. 2 and 3) on top of it for concealing the cell holder case and the connection between the same may be achieved in a similar manner as the cell tray (402a).
[0036] FIG. 5 illustrates an inside view of a battery pack when multiple battery modules are stacked to form the battery pack of FIG. 1 in accordance with an embodiment of the present disclosure. As is well known, plurality of battery cells may be arranged forming battery modules and these modules may be stacked up to form the battery pack. While stacking up the multiple cell holder case (502, 504) to form a battery pack as shown in FIG. 5, a thermal pad 506 may be disposed between the cell holder case 502 and 504 positioned on respective cell trays. In an example, the thickness of the thermal pad may be in the range of 0.5-2mm.
[0037] FIG. 6a-6c illustrates temperature variation across a battery pack during thermal cycling in accordance with an embodiment of the present disclosure. Particularly, FIG. 6a depicts temperature variation across the battery cells. As depicted therein, the temperature observed across the battery cells in the span of 1500 seconds, is in the range of 43.5-44.6 ℃. Likewise, FIG. 6b depicts temperature variation across the battery enclosure. As shown therein, the temperature observed across the battery enclosure in the span of 1500 seconds, is in the range of 43.4-44.5 ℃. Similarly, FIG. 6c depicts temperature variation across the cell trays. As illustrated therein, the temperature observed across the cell trays in the span of 1500 seconds, is in the range of 42.6-44.5 ℃. It may be noted here that the safe/ideal operating temperature range for the battery cells is usually in the range of 0 °C to 50 °C. The temperature observed across the cell trays and the enclosure of the battery pack indicate that the heat generated at the battery cells has been transferred to the cell trays and subsequently to the enclosure. Particularly, the close temperature ranges observed across the battery cells, cell trays and enclosure indicate effective heat transfer from the cells to the cell trays and subsequently to the enclosure. This efficient dissipation of heat results in maintaining the cells below their ideal operating temperature range, thereby preventing the formation of localized hot spots.
[0038] FIG. 7a-7b illustrates a graph showing the temperature variation of battery cells and cell trays during thermal cycling in accordance with an embodiment of the present disclosure. Particularly, FIG. 7a depicts a graph showing the temperature variation of battery cells and FIG. 7b depicts a graph showing the temperature variation of cell trays. It may be seen that the maximum temperature observed for the battery cells is 44.6 ℃, which falls within the ideal operating temperature range and certain temperature is also observed for the cell trays ranging from 39.9 ℃ to 42.6 ℃. The temperature observed in the cell trays indicates effective heat transfer from the battery cells, which facilitates maintain the cells at an optimal temperature and promotes uniform dissipation of heat, thereby enhancing the performance and lifespan of the battery pack.
[0039] FIG. 8 is a flow chart representing the steps involved in a method (800) of fabricating a battery pack in accordance with an embodiment of the present disclosure. The method includes forming a cell holder case by positioning a plurality of first cooling plates upright with each cooling plate at a first offset and a plurality of second cooling plates upright with each cooling plate at the first offset such that the plurality of first cooling plates and the plurality of second cooling plates intersect each other to form a grid configuration of rows and columns with the plurality of first cooling plates extending along the rows and the plurality of second cooling plates extending along the columns, thereby defining a plurality of grid cells, wherein each grid cell comprises a tubular slot integrally formed therein to insert a respective battery cell of the plurality of battery cells such that outer wall of each tubular slot abuts at least three walls of the corresponding grid cells in step (802).
[0040] The method (800) further includes providing at least one layer of thermally conductive and electrically insulative material in inner wall of the tubular slot substantially circumventing the battery cell, wherein the material remains solid throughout thermal cycling in step (804)
[0041] Furthermore, the method (800) includes providing a cell tray with a plurality of channels arranged in a grid pattern defining a plurality of accommodating spaces in step (806). Furthermore, the method includes affixing a respective thermal pad to each channel using thermally conductive adhesive in step (808). It may be noted here that the method steps may be performed in any order to arrive at the design disclosed herein without deviating from the scope of the present disclosure.
[0042] The present subject matter offers several advantages in terms of heat dissipation by integrating cooling plates and thermally conductive and electrically insulative material that surrounds the battery cells which remains solid throughout the thermal cycling. The heat generated during the thermal cycling is pulled away by the material which is in thermal contact with the cooling plates which is in direct thermal contact with the enclosure of the battery pack which is cooled by the ambient air outside the battery pack, allowing efficient cooling without the need for complex active cooling systems. This prevents localized overheating as the heat gets uniformly distributed and this ensures that the temperature of the battery cells remains within the safe operating limits, thereby enhancing the performance and lifespan of the battery pack. In addition to this, in automobiles run by battery packs, the above design is advantageous in terms of weight reduction which increases usability and convenience. Thus, the design not only streamlines the manufacturing and associated costs but also enhances operational safety. Furthermore, the cooling plates arrangement described herein enhances the uniform distribution of heat throughout the battery pack, even during cold temperatures, allowing for effective operation in cold environments.
[0043] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the disclosure and are not intended to be restrictive thereof.
[0044] While specific language has been used to describe the disclosure, any limitations arising on account of the same are not intended. As would be apparent to a person skilled in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein.
[0045] The figures and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, the order of processes described herein may be changed and are not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts need to be necessarily performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples.
, Claims:1. A battery pack (100) comprising:
a cell holder case (200), wherein the cell holder case (200) is formed by.
a plurality of first cooling plates (202a-202n, 302a-302n) positioned upright, each spaced apart by a first offset; and
a plurality of second cooling plates (204a-204n, 304a-304n) positioned upright, each spaced apart by the first offset such that the plurality of first cooling plates (202a-202n, 302a-302n) and the plurality of second cooling plates (204a-204n, 304a-304n) intersect each other forming a grid configuration of rows and columns with the plurality of first cooling plates (202a-202n, 302a-302n) extending along the rows and the plurality of second cooling plates (204a-204n, 304a-304n) extending along the columns, thereby defining a plurality of grid cells (206a-206n), wherein each grid cell (206a-206n) comprises a tubular slot (208a-208n, 308a-308n) integrally formed therein to insert a respective battery cell of the plurality of battery cells (312a-312n) such that outer wall of each tubular slot (208a-208n, 308a-308n) abuts at least three walls of the corresponding grid cell (206a-206n);
wherein inner wall of each tubular slot is provided with at least one layer (310a-310n) of thermally conductive and electrically insulative material substantially circumventing the battery cell, wherein the material remains solid throughout thermal cycling; and
a cell tray (402a), wherein the cell tray (402a) comprises:
a plurality of channels arranged in a grid pattern defining a plurality of accommodating spaces (S), wherein each channel is affixed with a thermal pad (404a-404n, 406a-406n) using a thermally conductive adhesive.
2. The battery pack (100) as claimed in claim 1, wherein each of the plurality of first cooling plates (202a-202n, 302a-302n) further comprises:
a first end (202a'-202n') emanating from the grid configuration, wherein the first end is in thermal contact with a first lateral wall (104) of an enclosure of the battery pack; and
a second end (202a''-202n'') emanating from the grid configuration, wherein the second end is in thermal contact with a second lateral wall (106) opposite the first lateral wall (104) of the enclosure of the battery pack, wherein the thermal contact is established using the thermally conductive adhesive.
3. The battery pack (100) as claimed in claim 1, wherein the cell tray (402a) is made of the thermally conductive and electrically insulative material and detachably placed intermediate to the cell holder case (200) and the enclosure such that the plurality of channels face the enclosure.
4. The battery pack (100) as claimed in claim 1, wherein the cell tray (402a) further comprises a plurality of recesses (408a-408n), each formed in one of the accommodating spaces (S) and aligned with a corresponding battery cell (312a-312n) to allow a terminal of the corresponding battery cell (312a-312n) to emanate from the recess (408a-408n).
5. The battery pack (100) as claimed in claim 1, wherein each of the plurality of first cooling plates (202a-202n, 302a-302n) and the plurality of second cooling plates (204a-204n, 304a-304n) is made of aluminum.
6. The battery pack (100) as claimed in claim 1, wherein the thermally conductive and electrically insulative material comprises a uniform mixture of graphene and a composite material mixed in a predetermined ratio.
7. The battery pack (100) as claimed in claim 6, wherein the predetermined ratio is 1:10 or 1:25.
8. The battery pack (100) as claimed in claim 6, wherein the composite material comprises any one or combination of polychloroprene, butyl rubber, polyisoprene rubber, styrene Butadiene, plastic ABS, FR, polyamide, polycarbonate, boron nitride.
9. A method (800) of fabricating a battery pack, comprising:
forming a cell holder case by positioning a plurality of first cooling plates upright with each cooling plate at a first offset and a plurality of second cooling plates upright with each cooling plate at the first offset such that the plurality of first cooling plates and the plurality of second cooling plates intersect each other to form a grid configuration of rows and columns with the plurality of first cooling plates extending along the rows and the plurality of second cooling plates extending along the columns, thereby defining a plurality of grid cells, wherein each grid cell comprises a tubular slot integrally formed therein to insert a respective battery cell of the plurality of battery cells such that outer wall of each tubular slot abuts at least three walls of the corresponding grid cell; (802)
providing at least one layer of thermally conductive and electrically insulative material in inner wall of the tubular slot substantially circumventing the battery cell, wherein the material remains solid throughout thermal cycling; (804)
providing a cell tray with a plurality of channels arranged in a grid pattern defining a plurality of accommodating spaces; (806) and
affixing a respective thermal pad to each channel using thermally conductive adhesive. (808)
10. An electric vehicle comprising:
a battery pack (100), wherein the battery pack (100) comprises:
a cell holder case (200), wherein the cell holder case (200) is formed by.
a plurality of first cooling plates (202a-202n, 302a-302n) positioned upright, each spaced apart by a first offset; and
a plurality of second cooling plates (204a-204n, 304a-304n) positioned upright, each spaced apart by the first offset such that the plurality of first cooling plates (202a-204n, 302a-302n) and the plurality of second cooling plates (204a-204n, 304a-304n) intersect each other forming a grid configuration of rows and columns with the plurality of first cooling plates (202a-202n, 302a-302n) extending along the rows and the plurality of second cooling plates (204a-204n, 304a-304n) extending along the columns, thereby defining a plurality of grid cells (206a-206n), wherein each grid cell (206a-206n) comprises a tubular slot (208a-208n, 308a-308n) integrally formed therein to insert a respective battery cell of the plurality of battery cells (312a-312n) such that outer wall of each tubular slot (208a-208n, 308a-308n) abuts at least three walls of the corresponding grid cell (206a-206n);
wherein inner wall of each tubular slot (208a-208n, 308a-308n) is provided with at least one layer (310a-310n) of thermally conductive and electrically insulative material substantially circumventing the battery cell, wherein the material remains solid throughout thermal cycling; and
a cell tray (402a), wherein the cell tray (402a) comprises:
a plurality of channels arranged in a grid pattern defining a plurality of accommodating spaces (S), wherein each channel is affixed with a thermal pad (404a-404n, 406a-406n) using a thermally conductive adhesive.
Dated this 08th day of November 2024

Signature

Jinsu Abraham
Patent Agent (IN/PA-3267)
Agent for the Applicant

Documents