Battery pack and vehicle including same

Abstract

Provided is a battery pack that improves upon conventional heat sink-based cooling methods by directly cooling battery cells while preventing temperature deviations between the battery cells, due to the positions thereof, within the battery pack. The battery pack of the present invention includes: a pack housing including a bottom plate, an outer frame, and a partition frame; and a plurality of battery cell assemblies accommodated in the pack housing, wherein the outer frame and the partition frame are provided with flow paths through which a cooling fluid can flow, and distribution holes and return holes in communication with the flow paths, so that the cooling fluid flows toward the battery cell assemblies to directly cool the battery cells therein.

Description

Battery pack and vehicle including same

[0001] The present invention relates to a battery pack and a vehicle including the same, and more particularly, to a battery pack having a cooling structure in which a cooling fluid for cooling battery cells is directly applied to the battery cells, and a vehicle including the same. This application claims priority to Korean Patent Application No. 10-2024-0030177, filed February 29, 2024, the entire disclosure of which is incorporated herein by reference.

[0002] Secondary batteries, which are highly applicable across product groups and possess electrical characteristics such as high energy density, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) that are powered by electrical power sources. These secondary batteries are widely used as an energy source for environmental friendliness and energy efficiency, not only because they can drastically reduce the use of fossil fuels, but also because they produce no byproducts from energy use.

[0003] Types of secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of a single secondary battery cell, or a single battery cell, is approximately 2.5 V to 4.5 V. Therefore, if a higher output voltage is required, a battery pack may be configured by connecting multiple battery cells in series. Furthermore, depending on the required charge / discharge capacity of the battery pack, a battery pack may be configured by connecting multiple battery cells in parallel. Therefore, the number of battery cells included in the battery pack may vary depending on the required output voltage or charge / discharge capacity.

[0004] When connecting battery cells in series or parallel to form a battery pack, the typical method involves first configuring a battery module by housing multiple battery cells in a module case, then assembling one or more of these battery modules to form the battery pack by adding other components. Recently, battery packs in the cell-to-pack form have also been manufactured, where multiple battery cells are not modularized, i.e., housed in a module case, but are housed directly in the pack housing.

[0005] In battery packs, the importance of technologies capable of efficiently cooling the heat generated by battery cells is growing as demand for battery capacity increases. Currently, a separate heat sink is assembled inside the battery pack. This method indirectly cools the battery cells by dissipating the heat generated by the battery cells to the outside of the pack through thermal conduction via refrigerant circulating within the heat sink.

[0006] However, these indirect battery packs require aluminum plate brazing and numerous separate components to manufacture heat sinks. This increase in cooling components in the battery pack is undesirable, as it reduces the volume-to-weight ratio in terms of energy density.

[0007] Furthermore, because the refrigerant conducts heat through the aluminum plate, its high thermal resistance limits its ability to increase cooling efficiency. Consequently, the temperature difference between the end of the battery cell, located near the refrigerant inlet port, and the other end, located farther away, can become exacerbated, leading to unsatisfactory overall cooling efficiency.

[0008] In particular, conventional indirect cooling structures suffer from high temperature deviations (△T) between battery cells due to temperature increases under rapid charging conditions and momentary high-power conditions. If this temperature deviation is not addressed, it can lead to safety and durability issues within the battery pack.

[0009] Poor cooling efficiency can accelerate battery cell deterioration, or, if thermal runaway (TR) occurs in some battery cells, the failure to respond quickly can lead to thermal propagation (TP). In severe cases, this can lead to catastrophic events such as battery pack fire or explosion, which can not only cause property damage but also pose safety risks. Thus, in battery packs using conventional indirect cooling methods using heat sinks, the likelihood of TR / TP occurring when a specific battery cell malfunctions occurs is high.

[0010] To address these issues, the development of a battery pack with a direct cooling structure, where the coolant can be applied directly to the battery cells, is required. Even in battery packs with this direct cooling structure, the design must be such that temperature differences between battery cells do not occur depending on their location within the pack.

[0011] Furthermore, sealing must be maintained to prevent refrigerant from leaking outside the pack housing. This is especially important for cell-to-pack battery packs, which do not have a module case.

[0012] The problem to be solved by the present invention is to provide a battery pack that improves the conventional heat sink cooling method, thereby directly cooling the battery cells and preventing temperature deviations between battery cells depending on the location of the battery cells within the battery pack.

[0013] The problem to be solved by the present invention is to provide a battery pack that can reduce the possibility of TR / TP occurrence, especially in a cell-to-pack type battery pack.

[0014] Another problem that the present invention seeks to solve is to provide a vehicle including such a battery pack.

[0015] The battery pack of the present invention for solving the above problem comprises a pack housing including a bottom plate, an outer frame, and a partition frame; and a plurality of battery cell assemblies accommodated in the pack housing, wherein a flow path for cooling fluid, and a distribution hole and a recovery hole connected to the flow path are provided inside the outer frame and the partition frame, so that the cooling fluid flows toward the battery cell assembly to directly cool the battery cells within the battery cell assembly.

[0016] At least a portion of the outer frame and partition frame may be hollow metal tubes.

[0017] At least a part of the outer frame and the partition frame includes a hollow portion, and the hollow portions of the outer frame and the partition frame are connected to form the passage, and the passage may have a structure of at least two layers stacked in the vertical direction.

[0018] The battery cell assembly includes a plurality of cylindrical secondary batteries arranged in rows and columns and standing vertically as the battery cells, the longitudinal dimension of the battery cell assembly being greater than the width dimension, and the longitudinal direction of the battery cell assembly being positioned along the front-rear direction of the battery pack.

[0019] The outer frame includes a pair of side frames arranged on both left and right sides of the bottom plate, and a front frame and a rear frame arranged on both front and rear sides, respectively, and the partition frame includes a cross frame arranged on the front and rear sides of the bottom plate or a center frame arranged on the left and right sides of the bottom plate, and the internal space of the pack housing is divided into a plurality of cell array spaces by the partition frame, and the battery cell assembly can be individually installed in each of the cell array spaces.

[0020] The above side frame, front frame, and cross frame are formed in a hollow rectangular shape, and have at least one rib in the height direction that divides the internal space into upper and lower parts, so that the hollow internal space is divided into a plurality of parts in the height direction, thereby providing a multi-layer structure in which the flow paths are stacked in the height direction, and the flow paths in the lower layers of the side frame, front frame, and cross frame are connected to each other, and the flow paths in the upper layers of the side frame, front frame, and cross frame are connected to each other.

[0021] The above distribution hole may be formed at a position that connects each of the cell array spaces with the upper layer's flow paths, and the above recovery hole may be formed at a position that connects each of the cell array spaces with the lower layer's flow paths.

[0022] An inlet port for introducing the cooling fluid may be formed at a position that connects the upper layer's flow paths, and a discharge port for discharging the cooling fluid may be provided at a position that connects the lower layer's flow paths.

[0023] The above inlet port and outlet port may be provided in the front frame.

[0024] The above distribution hole is located on the inside of the right side frame and the left side of the cross frame, and the recovery hole is located on the inside of the right side of the cross frame and the left side frame, so that the cooling fluid can be directly introduced into each of the cell array spaces from the longitudinal side of the battery cell assembly through the distribution hole and recovered from the longitudinal side of the battery cell assembly through the recovery hole.

[0025] The outer frame and partition frame surrounding the cell array space have the distribution holes and recovery holes arranged to correspond to each of the battery cell assemblies, and the cooling fluid in the passage can be distributed to each of the cell array spaces and recovered and discharged along an independent discharge path.

[0026] The above pack housing includes a top opening and may further include a filling member sealing the top opening.

[0027] The above filling material may be provided with potting resin.

[0028] It may further include a top frame that is bonded and joined with an adhesive between the upper surface of the outer frame and the upper surface of the outer frame.

[0029] The battery cell includes a vent portion at the bottom, the bottom plate includes a press-formed groove portion in which the battery cell assembly can be seated, and further includes a plastic supporter on the groove portion, and gas or flame ejected through the vent portion can move along a venting path defined by the plastic supporter within the groove portion.

[0030] The battery cell assembly may include a holder for receiving the lower portion of the battery cell so as to maintain a dense arrangement of the battery cells; a middle frame for supporting an upper portion of the battery cell than a position supported by the holder; and an adhesive member for fixing the holder and the battery cell.

[0031] The holder may include a main body having a plurality of receiving grooves formed in parallel to each other so that the battery cells are each inserted; and a spacer provided between the receiving grooves and configured to maintain a gap between the battery cells.

[0032] A cooling passage space is formed between the holder and the middle frame to be filled with the cooling fluid, and the middle frame can isolate the cooling fluid from the filling member.

[0033] In order to solve the above other problems, the present invention also provides a vehicle including a battery pack according to the present invention.

[0034] The present invention provides a battery pack using a direct cooling method that cools battery cells by introducing and circulating a cooling fluid inside the battery pack so that it comes into direct contact with the battery cells. This battery pack is implemented using immersion cooling, which has excellent cooling performance. Since the battery pack according to the present invention has superior cooling performance compared to the conventional indirect cooling method using a heat sink, it can solve the problem of heat generation, and in particular, the problem of heat generation due to rapid charging requirements. According to the present invention, it is possible to secure competitiveness by providing a differentiated solution that addresses the heat generation problem according to the rapid charging requirements of customers.

[0035] According to one embodiment of the present invention, a flow path structure can be implemented using a hollow tube in a frame constituting a pack housing, allowing cooling fluid to flow. This reduces costs and improves energy density by eliminating the need for a separate heat sink and related components.

[0036] Furthermore, the present invention enhances the cooling performance of battery cells through the uniform distribution and recovery of cooling fluid within the battery pack, as well as short-distance flow. Furthermore, each battery cell can be uniformly cooled regardless of its location within the pack. Consequently, temperature variations in heat generation can be minimized. Therefore, cooling efficiency can be further enhanced by minimizing temperature variations between battery cells.

[0037] According to one configuration of the present invention, a battery pack having a cell-to-pack type battery pack is provided that implements a waterproof and sealed structure through structural simplification and improves cooling efficiency through the application of an immersion cooling method. According to one configuration of the present invention, an efficient cooling path configuration is possible in a cell-to-pack type battery pack in which a cooling fluid circulates throughout the battery pack from the inlet port to the outlet port without a separate heat sink. Assembly complexity and assembly efficiency are significantly improved due to a reduction in the number of components required for the cooling line configuration.

[0038] According to the present invention, thermal balance between battery cells can be maintained by improving cooling efficiency. Furthermore, the cooling passage space implemented within the battery pack allows the use of both standard vehicle coolant and insulating oil. According to the present invention, a sealing structure can be maintained to prevent leakage of coolant or insulating oil, while still allowing the use of coolant or insulating oil circulated through the vehicle's cooling system.

[0039] According to the present invention, by implementing a liquid immersion cooling structure, the temperature rise of specific battery cells is suppressed, thereby improving TR / TP reliability. Since surrounding battery cells can be protected in the event of TR / TP failure due to a specific battery cell abnormality, a battery pack with particularly high safety can be provided, and the safety of vehicles including the battery pack can be sufficiently guaranteed.

[0040] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0041] FIG. 1 is an exploded perspective view of a battery pack according to one embodiment of the present invention.

[0042] FIG. 2 is a top view of a pack housing included in the battery pack of FIG. 1.

[0043] Fig. 3 is a modified example of Fig. 2.

[0044] Figure 4 is a drawing showing the frames disassembled to explain the euro configuration in the pack housing of Figure 2.

[0045] FIG. 5 is a schematic diagram illustrating the flow of cooling fluid in the battery pack of FIG. 1.

[0046] Figure 6 is a perspective view of a battery pack according to another embodiment of the present invention.

[0047] Figure 7 is a partially exploded perspective view of the battery pack of Figure 6.

[0048] Figure 8 is a cross-sectional view II' of Figure 6.

[0049] Figure 9 is a cross-sectional view taken along line II-II' of Figure 6.

[0050] FIG. 10 is a drawing for explaining a battery cell assembly included in the battery pack of FIG. 6.

[0051] FIG. 11 is a perspective view of a pack housing included in the battery pack of FIG. 6.

[0052] Figure 12 is an exploded perspective view of the pack housing shown in Figure 11.

[0053] Figure 13 shows the frames of the pack housing shown in Figure 11.

[0054] FIG. 14 is a perspective view of the pack housing from a different angle than FIG. 11 to show the inlet and outlet ports in the battery pack of FIG. 6.

[0055] FIG. 15 is a drawing for explaining a vehicle according to one embodiment of the present invention.

[0056] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that aligns with the technical spirit of the present invention.

[0057] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0058] In the drawings, the sizes of each component or specific parts of that component are exaggerated, omitted, or schematically illustrated for convenience and clarity of explanation. Therefore, the size of each component does not entirely reflect the actual size. If a detailed description of a related known function or configuration is judged to unnecessarily obscure the gist of the present invention, such description will be omitted. Furthermore, since identical or similar reference numerals indicate identical or similar elements, any redundant or repetitive descriptions in various embodiments will be omitted.

[0059] FIG. 1 is an exploded perspective view of a battery pack according to one embodiment of the present invention.

[0060] Referring to FIG. 1, a battery pack (1) according to one embodiment of the present invention includes a pack housing (10), a plurality of battery cell assemblies (60), and a top frame (90).

[0061] The pack housing (10) is a container that houses a battery cell assembly (60) and can be installed at a predetermined location within a vehicle. The pack housing (10) can include a bottom plate (20), an outer frame (30), and a partition frame (40).

[0062] The battery cell assembly (60) may include a plurality of battery cells (62). The plurality of battery cells (62) may be electrically connected to each other. The battery cell assembly (60) may be provided in a roughly rectangular parallelepiped shape having a width (X-direction dimension), a length (Y-direction dimension), and a height (Z-direction dimension). In this case, the length may be longer than the width. The width also represents a dimension along the width direction (or left-right direction) of the battery pack (1), and the length represents a dimension along the length direction (or front-back direction) of the battery pack (1). The battery cell assembly (60) does not include a separate module case that surrounds and houses the entire plurality of battery cells (62), and the battery pack (1) may be implemented as a cell-to-pack type battery pack.

[0063] The battery cell (62) refers to a secondary battery including an electrode assembly, an electrolyte, and a battery case, and may be provided as a cylindrical secondary battery, a pouch-type secondary battery, or a square secondary battery. Hereinafter, in the present embodiment, a plurality of battery cells (62) as illustrated in FIG. 1 will be described as being limited to a cylindrical secondary battery. These battery cells (62) may be a plurality of cylindrical secondary batteries that are arrayed along columns (Y direction) and rows (X direction) and stand upright in the vertical direction (Z direction). For example, the battery cell (62) may be a 4680 type battery cell. Here, 4680 represents a form factor. The first two numbers in the form factor represent the diameter of the secondary battery, and the remaining numbers represent the height of the secondary battery. The 4680 cell has high efficiency and a large size compared to the existing 18650 cell or 21700 cell.

[0064] The bottom plate (20) provides a space for placing the battery cell assembly (60), and can be configured in the form of a flat plate with a relatively large area. It is positioned at the bottom of the battery cell assembly (60) to support and cover the bottom of each battery cell assembly (60).

[0065] The outer frame (30) and the partition frame (40) are vertically connected to the bottom plate (20) and can also be connected to each other. The outer frame (30) and the partition frame (40) may each be an extruded structure of metal. In particular, at least a portion of the outer frame (30) and the partition frame (40) may be a hollow tube manufactured by extruding a metal such as aluminum with a mixture of hollow parts and ribs inside. The frames (30, 40) may be welded and / or bolted to the bottom plate (20) to form the pack housing (10), and are preferably assembled by welding.

[0066] FIG. 2 is a top view of a pack housing included in the battery pack of FIG. 1, and FIG. 3 is a modified example of FIG. 2.

[0067] Referring to FIGS. 1 to 3, the outer frame (30) is formed at a predetermined height on the outer side of the bottom plate (20), and at least a portion of the outer frame (30) may be a hollow tube as mentioned above. For example, the outer frame (30) may be composed of a pair of side frames (32) each disposed on the left and right sides of the bottom plate (20), and a front frame (34) and a rear frame (36) each disposed on the front and rear sides, and these may be disposed on the side, front, and rear sides of the bottom plate (20), respectively. The side frames (32), the front frame (34), and the rear frame (36) may be assembled from separate parts or may be integral parts that are connected to each other. The assembly may be performed in various ways, such as fitting, bolting, bonding, and welding, and welding is preferred. The outer frame (30) is vertically coupled along the perimeter of the edge of the bottom plate (20) to form a wall. In the pack housing (10), the front frame (34) can form a front wall, the rear frame (36) can form a rear wall, and the side frame (32) can form a left side wall and a right side wall, respectively.

[0068] The partition frame (40) is a structure that divides an internal space formed by a bottom plate (20) and an outer frame (30), that is, an internal space defined in a box shape by the bottom plate (20) and the outer frame (30), into a plurality of sections. At least a part of the partition frame (40) may be a hollow square tube as mentioned above.

[0069] In FIGS. 1 and 2, the partition frame (40) includes a cross frame (42). In the modified example shown in FIG. 3, the partition frame (40) includes a cross frame (42) and a center frame (44). As such, the partition frame (40) may include the cross frame (42) and / or the center frame (44). The cross frame (42) may refer to a partition frame (40) arranged in the front-back direction on the bottom plate (20), and the center frame (44) may refer to a partition frame (40) arranged in the left-right direction on the bottom plate (20). The cross frame (42) may be coupled at both ends to the front frame (34) and the rear frame (36). The center frame (44) may be coupled at both ends to the left and right side frames (32). The pack housing (10) illustrated in FIG. 2 is provided with only a cross frame (42) without a center frame (44) as illustrated in FIG. 3. Conversely, a pack housing (10) provided with only a center frame (44) without a cross frame (42) may also be possible. In the modified example illustrated in FIG. 3, the partition frame (40) includes one cross frame (42) and one center frame (44). The number of cross frames (42) and center frames (44) may vary.

[0070] The battery cell assembly (60) can be positioned so that its longitudinal direction is along the front-rear direction of the battery pack (1). Then, the side frame (32) and the cross frame (42) extend along the longitudinal direction of the battery cell assembly (60). The battery cell assembly (60) can be positioned so that its width direction is along the left-right direction of the battery pack (1). Then, the front frame (34) and the rear frame (36) extend along the width direction of the battery cell assembly (60). When the pack housing (10) also includes a center frame (44), the center frame (44) also extends along the width direction of the battery cell assembly (60).

[0071] In order to accommodate two or more battery cell assemblies (60), there may be one or more cross frames (42) or one or more center frames (44). In order to accommodate four or more battery cell assemblies (60), one or more cross frames (42) and one or more center frames (44) may be included. It will be appreciated that the number of center frames (44) and the number of cross frames (42) included in the pack housing (10) may vary depending on the size and aspect ratio of the battery pack (1), the size and aspect ratio of the battery cell assembly (60), etc., as illustrated in FIGS. 2 and 3 . In this way, the internal space of the pack housing (10) may be divided into a plurality of zones by the partition frame (40), i.e., the cross frame (42) and / or the center frame (44), and the battery cell assemblies (60) may be individually installed in each zone. In this case, each zone may be defined as a cell array space (M) in the present invention. In the present invention, the battery cell assemblies (60) can be individually installed in each of the plurality of cell array spaces (M). The battery cell assemblies (60) can be arranged neatly within the pack housing (10) in a substantially rectangular shape, and each battery cell assembly (60) can be connected to secure the power required for driving the vehicle.

[0072] In the case of an example in which the pack housing (10) includes only one cross frame (42) as a partition frame (40) as in FIGS. 1 and 2, there are two cell array spaces (M) and two battery cell assemblies (60) can be stored. At this time, the battery cell assemblies (60) are stored side by side in the left-right direction. The longitudinal side of the left battery cell assembly (60) faces the inner side of the left side frame (32), i.e., the right side, and the left side of the cross frame (42). The longitudinal side of the right battery cell assembly (60) faces the right side of the cross frame (42) and the inner side of the right side frame (32), i.e., the left side. The widthwise side of each battery cell assembly (60) faces the inner side of the front frame (34) and the inner side of the rear frame (36).

[0073] In the case of an example where the pack housing (10) includes only one center frame (44), the number of cell array spaces (M) and battery cell assemblies (60) is still two, but the battery cell assemblies (60) are housed side by side in the front-to-rear direction. The longitudinal side of each battery cell assembly (60) faces the inner side of the left side frame (32) and the inner side of the right side frame (32). The widthwise side of the battery cell assembly (60) located at the front faces the inner side of the front frame (34) and the front side of the center frame (44), and the widthwise side of another battery cell assembly (60) located at the rear faces the rear side of the center frame (44) and the inner side of the rear frame (36).

[0074] In addition, in the example of FIG. 3, four cell array spaces (M) are provided and four battery cell assemblies (60) are stored. In each cell array space (M), each battery cell assembly (60) is configured to have a structure in which the sides are surrounded by an outer frame (30) and a partition frame (40). In addition, since the battery cell assemblies (60) are individually installed in each of the plurality of cell array spaces (M), the battery cell assemblies (60) are separated from other battery cell assemblies (60) installed in other cell array spaces (M) and can be prevented from affecting each other.

[0075] In this way, in the present invention, each battery cell assembly (60) is individually installed in each cell array space (M), and is surrounded on the sides by an outer frame (30) and a partition frame (40) so that it can be stored inside the battery pack (1) separately from other battery cell assemblies (60), and all battery cell assemblies (60) can be placed under similar conditions.

[0076] Referring mainly to FIG. 1, the battery cell assembly (60) can be packaged so as not to be exposed to the outside by the pack housing (10) and the top frame (90). A sealing member (not shown), such as a gasket, may be provided between the pack housing (10) and the top frame (90) to seal them. For example, the sealing member may be a band shape that follows the shape of the perimeter of the pack housing (10). The sealing member may be made of a material that exhibits a predetermined elasticity so as to stably exhibit a desired sealing force by the pressure applied when the pack housing (10) and the top frame (90) are coupled, and may be compressed or deformed in the vertical direction by the pressure. The sealing member may be made of a rubber material, for example, an EPDM material.

[0077] The battery pack (1) may have an approximately rectangular parallelepiped appearance due to the combination of the pack housing (10) and the top frame (90). When the battery pack (1) is mounted on an electric vehicle such as an EV or HEV, the mounting space is limited due to the vehicle components arranged at a high degree of integration. Therefore, it is preferable that the battery pack (1) be formed into a rectangular parallelepiped structure so that it can be mounted in a narrow space such as between the driver's seat and the passenger seat.

[0078] In the example illustrated in Fig. 1, the top frame (90) is expressed in a roughly plate shape, but the top frame (90) may also have a flat box lid shape with an inner receiving space and an open bottom. The top frame (90) may be made of an insulating resin for electrical insulation. For example, the top frame (90) may be manufactured as a plastic injection molded product. Such a top frame (90) has the advantage of ensuring insulation from the battery cell assembly (60), and also provides convenience in processing and reduces manufacturing costs.

[0079] The pack housing (10) provides mechanical support to the battery cell assembly (60) and serves to protect it from external impacts, etc., so it is preferable to manufacture it from a metal material with high rigidity. It may be preferable that the entire pack housing (10) be manufactured from a metal material with high mechanical rigidity. For example, the outer frame (30) and the partition frame (40) may be made of aluminum or steel, and the bottom plate (20) may also be made of aluminum or steel, and it is preferable to manufacture it from aluminum for lightweight and easy processing. If the pack housing (10) is made of metal, an insulating sheet (not shown) may be further included on the bottom plate (20) to provide insulation. For example, the insulating sheet may be a polycarbonate sheet. As another example, an insulating coating layer may be included on the upper surface of the bottom plate (20). The insulating coating layer may be formed by coating, applying, or attaching an insulating material of any one of silicone resin, polyamide, and rubber. With this insulating coating layer configuration, the insulating coating effect can be maximized with a minimum amount of coating. In addition, since an insulating coating layer is applied to the upper surface of the bottom plate (20), the insulation between the battery cell assembly (60) and the bottom plate (20) can be strengthened. As another example, the pack housing (10) may be manufactured with at least some of its components made of plastic injection molding. For example, the outer frame (30) and the partition frame (40) may be made of metal, and the bottom plate (20) may be manufactured with a plastic material to reduce weight. In this case, the bottom plate (20) may be formed of a plastic material (e.g., polycarbonate, etc.) that has both insulating and flame retardant properties.

[0080] In particular, at least a portion of the outer frame (30) and the partition frame (40) may preferably be aluminum hollow tubes. By manufacturing the outer frame (30) and the partition frame (40) with aluminum hollow tubes and welding them together to form the pack housing (10), the weight of the pack housing (10) can be reduced and the mechanical rigidity can be maintained at a reliable level or higher. In addition, the hollow portion within the tubes can serve as a passage for a cooling fluid that can cool the battery cell assembly (60) inside the battery pack (1) while reducing the weight of the frames (30, 40). The passage for the cooling fluid, i.e., the flow path, can be configured by connecting the hollow portions of the frames (30, 40), and the flow path can have a structure of at least two layers stacked in the vertical direction. In this way, since the internal hollow space of the frames (30, 40) is utilized rather than configuring the euro separately, the process efficiency can be increased while also simplifying the fastening structure, and the energy density can be increased by increasing the utilization rate of the internal space of the battery pack (1).

[0081] In FIGS. 1 to 3, it is illustrated that a plurality of holes (H1, H2) are formed in the frames (30, 40) surrounding each cell array space (M) to connect each cell array space (M) with a flow path inside the frames (30, 40). In FIGS. 1 to 3, reference numeral 82 is an inlet port that can introduce cooling fluid into the flow path, and reference numeral 84 is a discharge port that can discharge cooling fluid from the flow path.

[0082] As will be described in detail with reference to FIGS. 4 and 5 below, the cooling fluid may be introduced from the inlet port (82) and distributed to the battery cells (62) through the distribution hole (H1) to directly cool the battery cells (62). The cooling fluid may be filled between the battery cells (62) or may flow between the battery cells (62). The cooling fluid may be recovered through the recovery hole (H2) and discharged to the outside of the battery pack (1) through the discharge port (84). The cooling fluid may be coolant, but is preferably a liquid having insulating properties. In particular, it may be insulating oil. The insulating oil has high withstand voltage performance. Using the insulating oil can prevent short circuits or safety issues due to leakage. Since the insulating oil does not have a vaporization property, it can be used semi-permanently without replacement. The insulating oil may be an insulating oil such as 3M Novec. Such insulating oil has excellent insulating performance, allowing cooling through direct contact with the battery cells (62), and has a variety of boiling points, allowing phase change cooling to be applied. The battery pack (1) can be installed in a vehicle such as an electric vehicle such as an EV or HEV, and the insulating oil may be an oil similar to the engine oil or gear oil of the vehicle.

[0083] The cooling fluid may be a phase change material (PCM). The PCM can cycle through vaporization and liquefaction, and for more effective cycling, it may be prepared with a fluorine-based, low-boiling-point material. For example, the PCM may be prepared with a material having a boiling point of 35°C to 50°C. In addition, the PCM may include a material having a fire-extinguishing function. Accordingly, even if a fire occurs within the battery pack (1), the PCM can be quickly extinguished.

[0084] According to the present invention, a battery pack (1) utilizing a direct cooling method using a cooling fluid can be implemented. This battery pack (1) can maintain thermal balance between battery cells (62) due to improved cooling efficiency. Furthermore, both general vehicle coolant and insulating oil can be used through the cooling passage space implemented within the battery pack (1).

[0085] After manufacturing the outer frame (30) and the partition frame (40) as hollow square tubes, by welding them so that at least some of the hollow sections can be connected as intended, the temperature of the battery cell assembly (60) can be lowered by allowing cooling fluid to enter / circulate through the hollow sections along an intended path to absorb and discharge heat generated in the battery cell assembly (60). In particular, when at least some of the hollow sections are connected, a cooling fluid passage is formed through which cooling fluid is supplied to and recovered from the battery cell assembly (60) over a short distance.

[0086] Figure 4 is a drawing showing the frames disassembled to explain the euro configuration in the pack housing of Figure 2.

[0087] In Fig. 4, it is exemplified that a flow path for cooling fluid is provided within the side frame (32) and the front frame (34) among the outer frames (30), and a flow path for cooling fluid is provided within the cross frame (42) among the partition frames (40). Referring to Fig. 4, in the present embodiment, the side frame (32), the front frame (34), and the cross frame (42) are formed in a hollow rectangular shape, and at least one rib dividing the internal space into upper and lower parts is provided in the height direction, so that the hollow internal space is divided into a plurality of parts in the height direction, so that the flow paths (32a, 32b) are stacked in the height direction in the side frame (32), the flow paths (34a, 34b) are stacked in the height direction in the front frame (34), and the flow paths (42a, 42b) are stacked in the height direction in the cross frame (42), thereby forming a multi-layer structure.

[0088] In this way, when the outer frame (30) or the partition frame (40) is provided with a flow path, these flow paths may be connected to each other. The flow paths (32a, 34a, 42a) of the lower hollow portion, i.e., the lower space, may be connected to each other, and the flow paths (32b, 34b, 42b) of the upper hollow portion, i.e., the upper space, may be configured to be connected to each other. In this way, a flow path structure through which a cooling fluid can move can be implemented by using an aluminum hollow tube in the frames (30, 40). A thermal runaway situation in which a battery cell catches fire due to overcharging, etc. may occur, but the present invention proposes to prevent such a thermal runaway situation from occurring by directly supplying a cooling fluid into the inside of a battery pack (1) to cool the battery cell (62), by providing a cooling fluid path inside an outer frame (30) and a partition frame (40) constituting a pack housing (10), so that the cooling fluid can be circulated through the path to discharge the heat of the battery cell (62) to the outside. Cost reduction and energy density improvement are possible by eliminating a separate heat sink and related parts.

[0089] Referring to FIGS. 1, 2, and 4 together, in each cell array space (M), the longitudinal side of each battery cell assembly (60) faces the side frame (32) and the cross frame (42). In each cell array space (M), the widthwise side of each battery cell assembly (60) faces the front frame (34) and the rear frame (36). At this time, a plurality of holes (H1, H2) may be formed in the frames (30, 40) surrounding each cell array space (M) to connect each cell array space (M) and the flow paths (32a, 32b, 34a, 34b, 42a, 42b). The number and positions of the holes (H1, H2) may be configured differently as needed. Preferably, the distribution hole (H1) allows cooling fluid to be supplied over a short distance to the battery cell assembly (60) mounted within each cell array space (M). The recovery hole (H2) allows cooling fluid to be recovered over a short distance from the battery cell assembly (60) mounted within each cell array space (M).

[0090] In the present embodiment, the distribution hole (H1) may be formed at a position that connects each cell array space (M) with the upper layer flow paths (32b, 34b, 42b). The recovery hole (H2) may be formed at a position that connects each cell array space (M) with the lower layer flow paths (32a, 34a, 42a). In addition, only the distribution hole (H1) may be formed in the right side frame (32), only the recovery hole (H2) may be formed in the left side frame (32), and both the distribution hole (H1) and the recovery hole (H2) may be formed in the cross frame (42). In particular, in the cross frame (42), the distribution hole (H1) and the recovery hole (H2) may be formed on opposite sides.

[0091] The battery pack (1) further includes an inlet port (82) for introducing cooling fluid and a discharge port (84) for discharging cooling fluid. In the present embodiment, the inlet port (82) is provided in the front frame (34) at a position communicating with the upper flow paths (32b, 34b, 42b). The discharge port (84) is provided in the front frame (34) at a position communicating with the lower flow paths (32a, 34a, 42a). The inlet port (82) and the discharge port (84) may be provided in the central portion of the front frame (34) to uniformly distribute and recover the cooling fluid. As another example, the inlet port (82) may be provided at the left end or the right end of the upper flow path (34b) of the front frame (34), and the discharge port (84) may be provided at the end of the lower flow path (34a) below the inlet port (82). As another example, the inlet port (82) may be provided at the left end of the upper flow path (34b) of the front frame (34), and the outlet port (84) may be provided at the right end of the lower flow path (34a). The upper flow paths (32b, 34b, 42b) and the lower flow paths (32a, 34a, 42a) are not connected.

[0092] The cooling fluid introduced into the inlet port (82) moves along the upper flow paths (32b, 34b, 42b) and then flows into each cell array space (M) from the distribution hole (H1) to cool the battery cells (62), and then flows into the recovery hole (H2), moves along the lower flow paths (32a, 34a, 42a), and then is discharged through the discharge port (84). Through this, the battery pack (1) can be implemented as a direct-type battery pack that cools the battery cells (62) by introducing and circulating a cooling fluid such as coolant or insulating oil into the battery cells (62) so that it directly contacts them. This battery pack (1) is an immersion-cooled battery pack with excellent cooling performance. Since the battery pack (1) has excellent cooling performance compared to the indirect method using a conventional heat sink, it can solve the problem of heat generation, and in particular, it can solve the problem of heat generation according to rapid charging requirements. The battery pack (1) can secure competitiveness by providing a differentiated solution to solve the heat generation problem according to the customer's rapid charging requirements.

[0093] In this embodiment, it can be said that the upper layer passages (32b, 34b, 42b) constitute a cooling fluid supply passage, and the lower layer passages (32a, 34a, 42a) constitute a cooling fluid discharge passage. That is, the cooling fluid supply passage is positioned higher than the cooling fluid discharge passage.

[0094] FIG. 5 is a schematic diagram illustrating the flow of cooling fluid in the battery pack of FIG. 1.

[0095] Referring to FIGS. 4 and 5, in the present embodiment, a cooling fluid is introduced into the frames (30, 40) through an inlet port (82), particularly into a flow path (34b) of an upper layer of the front frame (34). The cooling fluid flows along the flow path (34b) (arrow A) and is distributed to other upper flow paths (32b, 42b) connected to the flow path (34b) (arrow B). The cooling fluid introduced into the upper flow paths (32b, 42b) moves along the flow paths (32b, 42b) and directly flows into each cell array space (M) inside the battery pack (1) from the longitudinal side of the battery cell assembly (60) through a distribution hole (H1) connected thereto (arrow C). The introduced cooling fluid moves along the width direction of the battery cell assembly (60) to cool the battery cell (62) and then flows into the recovery hole (H2). The cooling fluid is recovered from the longitudinal side of the battery cell assembly (60) through the recovery hole (H2) at a short distance. The recovery hole (H2) is connected to the lower flow paths (32a, 42a). The cooling fluid that enters the recovery hole (H2) flows along the lower flow paths (32a, 42a) (arrow D) and then flows into the lower flow path (34a) of the front frame (34) connected thereto. A discharge port (84) is provided here, so that the cooling fluid that has moved along the flow path (34a) (arrow E) can be discharged to the outside of the battery pack (1) through the discharge port (84). By positioning the distribution hole (H1) at a position facing the longitudinal side of the battery cell assembly (60), the cooling fluid can be brought into contact with the battery cell (62) over a short distance, and by positioning the recovery hole (H2) at a position facing the longitudinal side of the battery cell assembly (60) at a position facing the distribution hole (H1), the cooling fluid heated by taking heat from the battery cell (62) can be quickly recovered. That is, according to the present invention, the cooling fluid can be moved over a short distance within each cell array space (M) to maximize cooling efficiency.

[0096] In this way, inside the frames (30, 40), the channels (32b, 34b, 42b) for introducing the cooling fluid and the channels (32a, 34a, 42a) for recovering the cooling fluid can be configured in a vertically stacked manner, and the distribution hole (H1) is formed on the side facing the longitudinal side of the battery cell assembly (60) in the frames (30, 40) while communicating with the channels (32b, 34b, 42b) for introducing the cooling fluid, so that the cooling fluid can be introduced to the battery cell assembly (60) side along the width direction, which is a shorter distance between the length direction and the width direction. Regarding the battery cell assembly (60), the cooling fluid flows a short distance along the width direction and then, inside the frames (30, 40), communicates with the cooling fluid recovery paths (32a, 34a, 42a) and is recovered directly through the recovery hole (H2) formed on the side facing the longitudinal side of the battery cell assembly (60) in the frames (30, 40).

[0097] According to the present invention, each cell array space (M) may have a structure in which the sides are surrounded by a partition frame (40), or may have a structure in which the sides are surrounded by an outer frame (30) and a partition frame (40). Holes (H1, H2) are arranged in the frames (30, 40) surrounding each cell array space (M) to correspond to each battery cell assembly (60). The cooling fluid introduced from the inlet port (82) is distributed almost similarly to all battery cell assemblies (60) through the flow paths (32b, 34b, 42b) of the upper space, and after flowing with a similar flow distance in each cell array space (M), it can be recovered and discharged along an independent discharge path through the flow paths (32a, 34a, 42a) of the lower space. By using a sealed structure by a top frame (90), it is possible to configure a cooling fluid that cools one battery cell assembly (60) and a cooling fluid that cools another battery cell assembly (60) to circulate along independent paths without mixing and without affecting each other.

[0098] According to the present invention, the coolant or insulating oil circulated through the vehicle cooling system of the automobile can be used to directly cool the battery cell (62) while maintaining the sealing property so that the coolant or insulating oil does not leak, and the cooling performance of the battery cell (62) can be improved through the uniform distribution and recovery of the coolant fluid within the battery pack (1) and short-distance flow, and each battery cell (62) can be uniformly cooled regardless of the location of the battery cell (62) within the battery pack (1). Accordingly, the temperature difference of the heat generation can be minimized. Therefore, the cooling efficiency can be further improved by minimizing the temperature difference between each battery cell (62).

[0099] According to the present invention, by implementing a liquid immersion cooling structure, the temperature rise of specific battery cells is suppressed, thereby improving TR / TP reliability. Since surrounding battery cells can be protected in the event of TR / TP failure due to a specific battery cell abnormality, a battery pack with particularly high safety can be provided, and the safety of vehicles including the battery pack can be sufficiently guaranteed.

[0100] By controlling the inflow and discharge rates of the cooling fluid, the battery pack (1) can be filled with cooling fluid for immersion cooling, or can be cooled without filling. When the cooling fluid is fully filled, uneven cooling can be prevented from occurring depending on the angle when the battery is in operation, such as when driving an electric vehicle on an incline. According to the present invention, cooling can be performed by flowing the cooling fluid while fully filled inside the battery pack (1).

[0101] According to the present invention, cooling can be performed by allowing the cooling fluid to flow within the battery pack (1) without being fully charged. When used without being fully charged, cooling utilizing the phase change of insulating oil is advantageous.

[0102] Hereinafter, a battery pack (100) according to another embodiment of the present invention will be described with reference to FIGS. 6 to 14. In the drawings below, reference numerals that are identical or similar to those given in FIGS. 1 to 5 indicate identical or similar components. For example, the pack housing (10) in FIG. 1 corresponds to the pack housing (110) below. Although descriptions overlapping with those described above are omitted below, it will be appreciated that the same or modified versions thereof may be applied to the following embodiments.

[0103] FIG. 6 is a perspective view of a battery pack according to another embodiment of the present invention, and FIG. 7 is a partially exploded perspective view of the battery pack of FIG. 6.

[0104] Referring to FIGS. 6 and 7, the battery pack (100) includes a pack housing (110), a plurality of battery cell assemblies (160), a filling member (170), and a top frame (190).

[0105] Fig. 8 is a cross-sectional view taken along line II' of Fig. 6, and Fig. 9 is a cross-sectional view taken along line II-II' of Fig. 6. Fig. 10 is a drawing for explaining a battery cell assembly included in the battery pack of Fig. 6, and Fig. 11 is a perspective view of a pack housing included in the battery pack of Fig. 6. Fig. 12 is an exploded perspective view of the pack housing shown in Fig. 11. Fig. 13 shows frames of the pack housing shown in Fig. 11. Fig. 14 is a perspective view of the pack housing taken at a different angle from Fig. 11 to show an inlet port and an outlet port in the battery pack of Fig. 6.

[0106] Referring to FIGS. 6 to 14 together, the pack housing (110) is a container that houses the battery cell assembly (160) and can be disposed at a predetermined location within the vehicle. In particular, referring to the cross-sections of FIGS. 8 and 9, the internal components of the battery pack (1) can be confirmed. The detailed structure of the battery cell assembly (160) can be seen with reference to FIG. 10.

[0107] The pack housing (110) may include a bottom plate (120), an outer frame (130), and a partition frame (140). The pack housing (110) accommodates a battery cell assembly (160) and, particularly, has an upper opening (O) as shown in FIG. 11 . The pack housing (110) has an open upper surface and provides an internal space. A top frame (190) may be coupled to the upper surface of the pack housing (110). For example, a bottom surface of the top frame (190) may be bonded to the upper surface of the outer frame (130) by bonding it therebetween using an adhesive (192). As shown in FIGS. 7 and 11 , the adhesive (192) may be positioned on the upper surface of the outer frame (130) along the frame-shaped outer frame (130), and may maintain the sealing property of the battery pack (1).

[0108] The battery pack (100) may further include an electrical component assembly. The electrical component assembly may include, for example, a relay device, a current sensor, a fuse, a BMS (Battery Management System), an MSD (Manual Service Disconnector), etc. (not shown). The relay device is a switching component that selectively opens and closes a charging and discharging path through which current flows, and may block the flow of charging and discharging current when an abnormality occurs in the battery pack (100). As illustrated in FIGS. 6 and 7, in the present embodiment, a relay box (180) including a relay device is positioned on a top frame (190), and an example in which the relay box (180) is packaged by a separate relay device cover (195) is illustrated.

[0109] BMS refers to a battery management device that controls the overall charging and discharging operation of a battery cell assembly (160), and can be said to be a component typically included in a battery pack (100). The BMS estimates the status of the battery cells in the battery pack (100) and manages the battery pack (100) using the estimated status information. For example, it estimates and manages battery pack (100) status information such as SOC (State Of Charge), SOH (State Of Health), maximum input / output power allowance, and output voltage of the battery pack (100). In addition, it controls charging or discharging of the battery pack (100) using this status information, and can also estimate the replacement time of the battery pack (100). The BMS manages and monitors the status of the battery cells such as voltage, current, and temperature, and maintains the battery pack (100) in an optimal state based on this. That is, the BMS efficiently manages the battery pack (100) of the electric vehicle to ensure stable driving of the electric vehicle, predicts the time to replace the battery pack (100), and detects abnormal conditions of the battery pack (100) in advance to control the vehicle so as to prevent automobile accidents. In addition, the MSD is a component that is a system for selectively cutting off the power of the high-voltage battery by a physical method and cuts off the power by disconnecting the service plug when necessary. This electrical component assembly can be packaged so as not to be exposed to the outside by the pack housing (110) and the top frame (190).

[0110] Referring mainly to FIG. 10, a battery cell assembly (160) may include a plurality of battery cells (162). The battery cells (162) may be a plurality of cylindrical secondary batteries arranged in rows (Y direction) and columns (X direction) and standing upright in the vertical direction (Z direction). An electrode assembly is housed in a battery case (162a) of the battery cell (162). The battery case (162a) is formed in a cylindrical shape, and the electrode assembly may be formed in a jelly roll type having a structure in which a positive electrode plate, a negative electrode plate, and a separator interposed between the positive and negative electrode plates are wound in one direction and a center hole is formed. The battery case (162a) may be electrically connected to the negative electrode plate of the electrode assembly. Accordingly, the battery case (162a) may have the same polarity as the negative electrode plate, i.e., a negative electrode. A cell terminal (162b) electrically connected to the positive electrode plate of the electrode assembly is extended outside the battery case (162a). The cell terminal (162b) has a positive polarity. A vent part (162c) may be provided at the bottom of the battery cell (162). The vent part (162c) may be configured to discharge venting gas. The vent part (162c) may be configured to be broken when the internal pressure of the battery case (162a) increases above a certain level. For example, the vent part (162c) may be a region structurally weaker than the surrounding region so that it may be easily broken. Specifically, the vent part (162c) may be a region having a thinner thickness than the surrounding region, for example. For example, the vent part (162c) may be provided as a roughly circular closed loop or a C-shaped notch as illustrated. The vent part (162c) ruptures when the pressure inside the battery cell (162) abnormally increases, thereby allowing the gas inside to be discharged to the outside. If the vent part (162c) is included at the bottom of the battery cell (162), it can be helpful in directing the discharge direction of the venting gas toward the bottom of the battery pack (100).Such a vent portion (162c) may be provided near the center of the bottom of the battery cell (162). A plurality of battery cells (162) may be electrically connected to each other. A bus bar (not shown) for electrical connection between the battery cells (162) may be further included at the top of the battery cell (162).

[0111] The battery cell assembly (160) may be provided in a roughly rectangular parallelepiped shape having a width (X-direction dimension), a length (Y-direction dimension), and a height (Z-direction dimension). The battery cell assembly (160) may be formed to extend in the front-rear direction. That is, the length may be longer than the width. The width also represents a dimension along the width direction (or left-right direction) of the battery pack (100), and the length represents a dimension along the length direction (or front-rear direction) of the battery pack (100). The battery cell assembly (160) does not include a separate module case that surrounds and houses a plurality of battery cells (162), and the battery pack (100) may be implemented as a cell-to-pack type battery pack.

[0112] As illustrated in FIG. 10, the battery cell assembly (160) may include a holder (164), a middle frame (166), and an adhesive member (165) to maintain a dense arrangement of battery cells (162). Each detailed configuration will be described later.

[0113] As shown in detail in Fig. 12, the bottom plate (120) provides a space for placing the battery cell assembly (160), and may be configured in the form of a flat plate having a relatively large area, and may be positioned at the bottom of the battery cell assembly (160) to support and cover the bottom of each battery cell assembly (160). In particular, the bottom plate (120) may have a groove (122) press-formed so that each battery cell assembly (160) can be seated therein. The groove (122) may be extended in the front-rear direction to fit the shape of the battery cell assembly (160).

[0114] Referring to FIGS. 8, 9, 11 to 14, the outer frame (130) and the partition frame (140) are vertically coupled to the bottom plate (120) and can also be coupled to each other. The outer frame (130) and the partition frame (140) may each be an extruded structure of metal. In particular, at least a portion of the outer frame (130) and the partition frame (140) may be a hollow tube manufactured by extruding a metal such as aluminum with a mixture of hollow parts and ribs therein. The frames (130, 140) may be welded and / or bolted to the bottom plate (120) to form the pack housing (110), and are preferably assembled by welding. The frames (130, 140) may be welded and / or bolted to the bottom plate (120) to form the pack housing (110).

[0115] At least a portion of the outer frame (130) and the partition frame (140) may preferably be made of aluminum hollow tubes. By manufacturing the outer frame (130) and the partition frame (140) with aluminum hollow tubes and welding them together to form the pack housing (110), the weight of the pack housing (110) can be reduced and the mechanical rigidity can be maintained at a reliable level or higher. In addition, the hollow portion within the tubes can serve as a passage for cooling fluid that can cool the battery cell assembly (160) inside the battery pack (100) while reducing the weight of the frames (130, 140). The passage for the cooling fluid, i.e., the flow path, can be formed by connecting the hollow portions of the frames (130, 140), and the flow path can have a structure of at least two layers stacked in the vertical direction. In the illustrated example, the hollow portions of the frames (130, 140) are made of four layers, and the middle two layers among them can be used as flow paths. The euro may have an inlet port (182) and an outlet port (184) connected to each other.

[0116] The outer frame (130) may be composed of a pair of side frames (132) arranged on both sides in the left-right direction (X direction) on the bottom plate (120), and a front frame (134) and a rear frame (136a, 136b) arranged on both sides in the front-back direction (Y direction). The outer frames (130) are vertically coupled along the edge of the bottom plate (120) to form a wall. In the pack housing (110), the front frame (134) may form a front wall, the rear frames (136a, 136b) may form a rear wall, and the side frames (132) may form a left-side wall and a right-side wall, respectively.

[0117] The partition frame (140) divides the internal space formed by the bottom plate (120) and the outer frame (130), i.e., the internal space defined in a box shape by the bottom plate (120) and the outer frame (130), into a plurality of sections. In the present embodiment, the partition frame (140) includes three cross frames (142).

[0118] The battery cell assembly (160) can be positioned so that its length direction is along the front-rear direction of the battery pack (100). Then, the side frame (132) and the cross frame (142) extend along the length direction of the battery cell assembly (160). The front frame (134) and the rear frames (136a, 136b) extend along the width direction of the battery cell assembly (160).

[0119] The internal space of the pack housing (110) is partitioned into a plurality of cell array spaces (M) by a partition frame (140), i.e., a cross frame (142). A battery cell assembly (160) can be individually installed in each of the corresponding spaces. In particular, as shown in FIG. 11, in the embodiment of the present invention, the cell array spaces (M) can be defined as a first zone (M1), a second zone (M2), a third zone (M3), and a fourth zone (M4) from the right.

[0120] Four battery cell assemblies (160) are stored side by side in the left-right direction. The longitudinal side of the battery cell assembly (160) mounted in the first zone (M1) faces the inner side of the right side frame (132) and the right side of the right cross frame (142). The longitudinal side of the battery cell assembly (160) mounted in the second zone (M2) faces the left side of the right cross frame (142) and the right side of the cross frame (142) located in the center. The longitudinal side of the battery cell assembly (160) mounted in the third zone (M3) faces the left side of the cross frame (142) located in the center and the right side of the left cross frame (142). The longitudinal side of the battery cell assembly (160) mounted in the fourth zone (M4) faces the left side of the left cross frame (142) and the right side of the left side frame (132). Additionally, the widthwise side of each battery cell assembly (160) faces the inner side of the front frame (134) and the inner side of the rear frame (142).

[0121] Referring mainly to FIGS. 8, 9, and 13, it is exemplified that a flow path for a cooling fluid is provided within the side frame (132) and the front frame (134) among the outer frames (130), and a flow path for a cooling fluid is provided within the cross frame (142). In the present embodiment, the side frame (132), the front frame (134), and the cross frame (142) are formed in a hollow rectangular shape, and at least one rib dividing the internal space into upper and lower parts is provided in the height direction, so that the hollow internal space is divided into a plurality of parts in the height direction, so that the flow paths (132a, 132b) are stacked in the height direction in the side frame (132), the flow paths (134a, 134b) are stacked in the height direction in the front frame (134), and the flow paths (142a, 142b) are stacked in the height direction in the cross frame (142), thereby forming a multi-layer structure.

[0122] In this way, when the outer frame (130) or the partition frame (140) is provided with a flow path, these flow paths may be connected to each other. The flow paths (132a, 134a, 142a) of the lower hollow portion, i.e., the lower space, may be connected to each other, and the flow paths (132b, 134b, 142b) of the upper hollow portion, i.e., the upper space, may be configured to be connected to each other. In this way, a flow path structure through which a cooling fluid can move can be implemented by using an aluminum hollow tube in the frames (130, 140). A thermal runaway situation in which a battery cell catches fire due to overcharging, etc. may occur, but the present invention proposes to prevent such a thermal runaway situation from occurring by directly supplying a cooling fluid into the inside of a battery pack (100) to cool the battery cell (162), by providing a cooling fluid path inside an outer frame (130) and a partition frame (140) constituting a pack housing (110), so that the cooling fluid can be circulated through the path to discharge the heat of the battery cell (162) to the outside. Cost reduction and energy density improvement are possible by eliminating a separate heat sink and related components.

[0123] This cooling fluid can be introduced toward the battery cell (162) to directly cool the battery cell (162). The cooling fluid can be either general vehicle coolant or insulating oil. That is, the cooling fluid can be a cooling fluid such as water or insulating oil.

[0124] After manufacturing the outer frame (130) and the partition frame (140) as hollow square tubes, by welding them so that at least some of the hollow sections can be connected as intended, the temperature of the battery cell assembly (160) can be lowered by allowing cooling fluid to enter / circulate through the hollow sections along an intended path to absorb and discharge heat generated in the battery cell assembly (160). In particular, when at least some of the hollow sections are connected, a cooling fluid passage is formed through which cooling fluid is supplied to and recovered from the battery cell assembly (160) over a short distance.

[0125] For welding between components constituting the pack housing (110), FWS, MIG, remote laser welding, etc. can be appropriately applied depending on the type, structure, and location of the components. For example, the outer frame (130) and the partition frame (140) are MIG welded to form a frame assembly, and the bottom plate (120) is assembled to the bottom surface of the frame assembly by FSW. The outer frame (130) and the partition frame (140) can be formed as hollow tubes, and by appropriately welding them, the layers inside the tubes can be connected in all directions, and if necessary, only some sections can be connected to form a flow path. Through the welding, the pack housing (110) achieves the basic skeletal structure of a cell-to-pack type battery pack (100), and forms a sealed system even when a flow path is provided.

[0126] The pack housing (110) provides mechanical support to the battery cell assembly (160) and the electrical component assembly and protects them from external impacts, etc., so it is preferable to manufacture it from a metal material with high rigidity. It may be preferable that the entire pack housing (110) be manufactured from a metal material with high mechanical rigidity. For example, the outer frame (130) and the partition frame (140) may be made of aluminum, and the bottom plate (120) may also be made of aluminum or steel. In order to provide insulation to the bottom plate (120), referring to FIG. 12, a plastic supporter (124) and a GF sheet (126) may be further included on the groove portion (122) of the bottom plate (120). In addition, a cell supporter (128) may be provided on the bottom plate (120) so as to support all of the battery cell assemblies (160) at once. A battery cell assembly (160) may be mounted on the cell supporter (128), and a plurality of venting holes may be formed in the cell supporter (128) at positions facing the vent portion (162c). The GF sheet (126) covers these venting holes and may be opened by a venting gas. The GF sheet (126) may be positioned between the cell supporter (128) and the battery cell assembly (160), or between the cell supporter (128) and the plastic supporter (124).

[0127] Referring back to FIG. 10 and looking at the detailed configuration of the battery cell assembly (160), the lower part of the battery cell (162) is accommodated in the holder (164). The holder (164) extends in the front-back direction according to the shape of the battery cell assembly (160). The holder (164) has a structure in which the lower part of the battery cell (162) is inserted. The holder (164) includes a plurality of receiving grooves (164a) that each accommodate a battery cell (162). The depth of the receiving grooves (164a) is a depth in which a portion of the height of the battery cell (162) is inserted, and the battery cell (162) can be fixed between the receiving grooves (164a) and the battery cell (162) by an adhesive member (165). In particular, the adhesive member (165) is a waterproof / structural adhesive. For example, it can be an epoxy-based waterproof resin. In this way, the adhesive member (165) can fix the holder (164) and the battery cell (162).

[0128] The receiving grooves (164a) are arranged parallel to each other so that the battery cells (162) can be inserted respectively. The receiving grooves (164a) are shaped to follow the outer surface of the cylindrical battery cell (162). Therefore, the receiving grooves (164a) are also cylindrical. The receiving grooves (164a) can support the side and bottom surfaces of the battery cells (162) at the bottom of the battery cells (162). The receiving grooves (164a) can separately receive the battery cells (162). When the battery cells (162) are inserted and received in an upright state in the receiving grooves (164a), movement in the up, down, left, and right directions can be prevented. The holder (164) not only serves to secure the battery cells (162) and fix the basic position of the battery cell assembly (160), but also serves to block flames from spreading to surrounding battery cells when the battery cell (162) catches fire. The holder (164) may include a spacer (164b) configured to maintain a gap between the battery cells (162) by being provided between the receiving grooves (164a). The spacer (164b) may be provided in a form that protrudes upward from the holder body (164). The spacer (164b) may be configured to maintain a gap between the battery cells (162). In addition, the spacer (164b) may be configured to guide the battery cells (162) to be inserted into the receiving grooves (164a) when assembling the battery cells (162).

[0129] The adhesive member (165) can be filled between the battery cells (162) to fix the battery cells (162) to each other. At this time, the adhesive member (165) can also be interposed between the battery cells (162) and the spacer (164b). In particular, the adhesive member (165) can prevent the cooling fluid from leaking to the lower side of the battery cell assembly (160). In addition, the adhesive member (165) can increase the heat dissipation efficiency of the battery cells (162), thereby further increasing the cooling performance of the battery cells (162). The adhesive member (165) can be made of any material that can improve the fixation and heat dissipation efficiency of the battery cells (162). As a result, a chain reaction of fire can be prevented when a thermal event occurs due to an abnormality in the battery cells (162). In addition, the adhesive member (165) can also serve as an insulation to prevent current flow to the adjacent battery cell (162) when damage or other abnormality occurs in at least one specific battery cell (162) among the plurality of battery cells (162). The adhesive member (165) can be applied to the side of the battery cell (162) and can also be applied to the vent part (162c) to prevent exposure of the vent part (162c). Even if a thermal runaway occurs due to an abnormality in one of the battery cells (162), the flame is not transmitted to the surrounding battery cells (162), so that it is not vulnerable to chain ignition.

[0130] The spacer (164b) may include a portion whose thickness becomes narrower as it goes in one direction. A portion may be provided in which the gap between the battery cell (162) and the spacer (164b) becomes wider as it goes in one direction. For example, the spacer (164b) may include a portion whose thickness becomes thinner as it goes upward. In this case, the lower portion of the spacer (164b) is in almost contact with the battery cell (162), and the spacer (164b) may be configured such that the distance from the battery cell (162) increases as it goes upward. According to the above-described exemplary configuration of the present invention, the adhesive member (165) may be guided to be accommodated in the space between the spacer (164b) and the battery cell (162). Accordingly, the space between the spacer (164b) and the battery cell (162) can be more reliably sealed, thereby more effectively preventing the cooling fluid from leaking to the outside.

[0131] The adhesive member (165) can stably fix the battery cell (162) and improve waterproof performance. The structure of the holder (164) as described above ensures that the adhesive member (165) and the battery cell (162) have a sufficient contact area at the contact surface.

[0132] The middle frame (166) also extends in the front-rear direction according to the shape of the battery cell assembly (160). The middle frame (166) supports a portion of the battery cell (162). The middle frame (166) supports the upper portion of the battery cell (162) above the position supported by the holder (164). Here, the battery cells (162) can be each inserted into and supported by the middle frame (166).

[0133] The holder (164) and the middle frame (166) can hold the battery cells (162) together in a single unit. The holder (164) and the middle frame (166) may be made of a composite material, such as FRP, that satisfies electrical insulation, mechanical strength, and lightweight requirements. Preferably, the holder (164) and the middle frame (166) are made of a material that can be formed by plastic injection molding.

[0134] The middle frame (166) can maintain a gap between the battery cells (162) at the top of the battery cells (162). The middle frame (166) may have a through hole (166a) formed therein for each battery cell (162) to pass through. The upper portion of the battery cell (162) may be inserted into the through hole (166a). In the present embodiment, since the battery cell (162) is a cylindrical secondary battery, the through hole (166a) of the middle frame (166) is circular.

[0135] A cooling passage space is formed between the holder (164) and the middle frame (166) to allow the cooling fluid to be filled between the battery cells (162). Referring to FIGS. 7 to 9, the filling member (170) seals the upper opening (O) of the bottom plate (120). As clearly shown in the cross-sections of FIGS. 8 and 9, the middle frame (166) prevents the filling member (170) filled above the middle frame (166) from penetrating into the cooling passage space. The middle frame (166) isolates the cooling fluid filled in the cooling passage space from the filling member (170). The middle frame (166) blocks the filling member (170) in the Z direction. The filling member (170) is provided on the upper side of the middle frame (166) to prevent leakage of the cooling fluid. The middle frame (166) is a key component that implements a flow space for cooling the battery cell (162) while preventing the filling member (170) from penetrating into the flow space.

[0136] A cooling passage space may be formed inside the battery pack (100) so that the side surfaces of the battery cells (162) are exposed, and a cooling fluid may be filled in the cooling passage space to flow and circulate or be maintained in a filled state. The cooling fluid may fill part or all of the height of the battery cells (162). The cooling fluid may be directly filled between the battery cells (162) in the cooling passage space between the middle frame (166) and the holder (164). In this way, the battery cells (162) may be immersed in the cooling fluid within the battery pack (100). This cooling fluid may serve to prevent the temperature of the battery cells (162) from increasing by directly cooling the battery cells (162), and has excellent cooling performance.

[0137] The cooling fluid can flow between the middle frame (166) and the holder (164). The cooling fluid can be in direct contact with the battery cells (162). Additionally, the cooling fluid can directly exchange heat with the battery cells (162).

[0138] According to the above-described embodiment of the present invention, the cooling performance of the battery cell (162) can be improved by using a direct cooling method. Furthermore, even if a problematic battery cell (162) ignites and its temperature rises, the cooling fluid inside the battery pack (100) is maintained so that heat is continuously transferred from the ignited battery cell (162) to cool the battery cell (162), thereby protecting the surrounding battery cells (162) from rising in temperature.

[0139] A filling member (170) on the upper side of the middle frame (166) is provided to prevent leakage of the cooling fluid. The filling member (170) may be provided with a potting resin. Here, potting refers to a method of injecting and applying a liquid resin to the upper side of the middle frame (166), then curing and packaging it. The filling member (170) may be a foam. The filling member (170) is a waterproof component that implements a seal to prevent the cooling fluid from leaking out of the battery pack (100). Therefore, the potting resin may be a potting resin with waterproof performance. The filling member (170) is filled inside the pack housing (110) over the middle frame (166) to seal the upper opening (O). The filling member (170) may be formed by placing the battery cell assembly (160) on the bottom plate (120), then applying and curing liquid resin through the upper opening (O).

[0140] In this way, according to the present invention, by implementing a waterproof structure through a filling member (170) such as a potting resin, a silicone rubber double injection structure or a waterproof foam tape is not required, so the number of parts is reduced and the assembly process is simplified. This enables cost reduction. The battery pack (100) is a battery pack with a simplified structure in the form of a cell-to-pack, a waterproof sealed structure can be implemented through the filling member (170), and cooling efficiency is improved through the application of a liquid immersion cooling method.

[0141] The waterproof structure using the filling member (170) of the present invention only requires filling the upper opening (O) above the middle frame (166), so waterproof performance is not achieved by inserting a separate member between parts requiring sealing and applying pressure by a separate fixing member. Waterproof foam tape, sealant, silicone rubber material parts such as O-rings, bolting structures, etc. are not required at all. Therefore, the manufacturing process of the battery pack (100) is very simple and the cost is reduced.

[0142] Meanwhile, the battery pack (100) can be sealed by the filling member (170) so that the battery pack (100) itself can form a closed system. The middle frame (166) maintains the gap between the battery cells (162) by serving as a guide that can maintain the gap between the battery cells (162) when assembled with the battery cells (162), thereby maintaining the gap between the cells, which is important in the direct cooling structure, at a constant level, thereby forming a uniform cooling passage space and reducing the differential pressure of the cooling fluid between the battery cell assemblies (160). In addition, after the filling member (170) is applied and hardened, it is an important component in making the battery pack (100) a closed system by preventing the filling member (170) from flowing into the cooling passage space.

[0143] The filling member (170) is a waterproof component that seals the upper opening (O), and at the same time, it more stably fixes the upper portion of the battery cell (162) protruding upward through the through hole (166a) of the middle frame (166), and at the same time, it increases the heat dissipation efficiency of the battery cell (162), thereby further enhancing the cooling performance of the battery cell (162).

[0144] For example, the filling material (170) may be prepared by mixing a potting resin with beads such as glass bubbles. The potting resin may be formed by injecting a thin liquid resin material into the battery cell (162) and curing it. Here, the injection of the resin material may be performed at a room temperature of approximately 15°C to 25°C to prevent thermal damage to the battery cell (162). Subsequent curing may be performed at a higher temperature.

[0145] In addition, the filling member (170) prevents the infiltration of moisture or foreign substances into the battery cell (162), prevents a chain reaction of fire when a thermal event occurs due to an abnormality in the battery cell (162), and further increases the structural rigidity of the battery pack (100).

[0146] Specifically, the filling member (170) may be formed of silicone resin. However, this is not limited thereto, and the filling member (170) may be formed of other resin materials that can improve the fixing and heat dissipation efficiency of the battery cell (162) and implement waterproof performance, in addition to the silicone resin.

[0147] The filling member (170) has a preset viscosity and may include at least two materials. Specifically, the filling member (170) may be prepared by mixing a preset resin and beads at a preset ratio. The filling member (170) reduces the cost of the potting resin by mixing the beads, and the viscosity and other physical properties of the filling member (170) may be adjusted according to the mixing ratio.

[0148] This filling member (170) guides the thermal equilibrium of the battery cell (162), thereby preventing cooling deviation of the battery cell (162) and thus preventing local deterioration of the battery cell (162). In addition, the safety of the battery pack (100) can also be significantly improved by preventing local deterioration of the battery cell (162).

[0149] In addition, the filling member (170) may also perform an insulating role to prevent current from flowing to an adjacent battery cell (162) when damage, etc. occurs due to an abnormal situation in at least one specific battery cell (162) among the battery cells (162).

[0150] In addition, the filling member (170) may be made of a material having high specific heat performance or may further include such a material. Accordingly, the filling member (170) increases the thermal mass, thereby delaying the temperature rise of the battery cell (162) even in situations such as rapid charging and discharging of the battery cell (162), thereby preventing a rapid temperature rise of the battery cell (162).

[0151] Additionally, the filling member (170) may be made of a material having high heat resistance or may further include such a material. Accordingly, the filling member (170) can effectively prevent thermal runaway from spreading to other adjacent battery cells (162) when a thermal event, such as overheating, occurs in a specific battery cell (162).

[0152] Additionally, the filling member (170) may be made of a material with high flame retardancy or may further include such a material. Accordingly, the filling member (170) can minimize the risk of fire in the event of a thermal event, such as overheating, in a specific battery cell (162).

[0153] In this way, the filling member (170) may be a potting resin with flame retardant / waterproof / adhesive performance. According to the present invention, by applying such a filling member (170), a waterproof structure can be easily and simply implemented even if the battery pack (100) has a large area. In particular, according to the present invention, since the top potting method is applied, a very simple waterproof sealing is implemented without the need for other waterproof parts. Therefore, since the structure of the cell-to-pack type battery pack (100) can be simplified, a direct cooling type battery pack (100) with a simplified assembly and manufacturing process can be obtained. Furthermore, since the number of parts is not large, it is not sensitive to foreign substances, etc. during the assembly and manufacturing process, the factors causing defects are reduced, and the manufacturing cost can be reduced.

[0154] Referring to FIGS. 11, 12, and 14, the battery cell assembly (160) described above is placed on a cell supporter (128). An adhesive may be applied to secure the battery cell assembly (160). In particular, the adhesive may be a waterproof / structural adhesive.

[0155] In the cell array space (M), the gas or flame generated from any one battery cell (162) is blocked from spreading laterally inside the battery pack (100) by the cross frame (142). In addition, the gas or flame is blocked from spreading upward inside the battery pack (100) by the filling member (170).

[0156] The space between the cell supporter (128) and the groove (122) can be utilized as a venting path. The plastic supporter (124) can define the venting path. The structure of the venting path can be confirmed in the cross-sections of FIGS. 8 and 9. In this way, the bottom plate (120) implements a support structure for the battery cell mounting portion while also implementing a flame path. The venting path can provide a predetermined space in which gas or flame flows at the bottom of the battery cell assembly (160). Safety can be ensured by preventing gas discharged from the battery cell (162) from spreading in all directions while guiding the venting gas to move in a predetermined direction, i.e., along the venting path.

[0157] When the vent portion (162c) is opened due to an abnormality in a specific battery cell (162), gas or flame may be normally discharged downward. The gas or flame may penetrate the GF sheet (126) and discharge downward. The discharged gas or flame may move along the venting path defined by the plastic supporter (124) within the groove portion (122) and discharge to the outside of the battery pack (100) through a venting device (not shown) that may be provided in the pack housing (110).

[0158] In this way, when a thermal event occurs in a battery cell (162) of the battery pack (100) and high-temperature gas or flames are generated, the gas or flames can be directed in a specific direction through a venting path within the cell array space (M) rather than in all directions, and discharged to the outside of the pack housing (110), and in the process of discharging the gas or flames to the outside of the pack housing (110), other battery cells (162) included in other battery cell assemblies (160) can be prevented from receiving thermal damage as much as possible.

[0159] In addition, according to the present invention, since the venting path is located below rather than above the battery pack (100), when high-temperature gas or flames are discharged from the battery cell (162) in a situation such as thermal runaway, the discharged gas or flames may not be directed upwards. In particular, in a case where a passenger is positioned above the battery pack (100), such as in an electric vehicle, the above-described configuration can suppress or delay the gas or flames from being directed toward the passenger. In particular, according to the embodiment of the present invention, directional venting can be performed below the battery pack (100) and laterally connected thereto, thereby enhancing the safety of users positioned above, such as passengers.

[0160] The battery pack (100) is a direct immersion cooling battery pack with excellent cooling performance. Because the battery pack (100) offers superior cooling performance compared to conventional heat sinks, it can address heat generation issues, particularly those related to rapid charging requirements. The battery pack (100) can secure competitiveness by providing a differentiated solution for resolving heat generation issues related to customers' rapid charging requirements.

[0161] In this way, the present invention can provide a simple and compact battery cell assembly (160) without complicating the overall structure and taking up a lot of space, and can be manufactured as a battery pack (100) in a cell-to-pack form by integrating such battery cell assemblies (160), and can suppress the occurrence of a temperature difference between one end and the other end of a battery cell (162) due to the direct cooling method. In addition, gas or flame can be safely discharged to the outside of the pack housing (110) along a predetermined venting path. In addition, a vehicle including such a battery pack (100) can be provided. A vehicle including such a battery pack (100) can have improved safety and durability.

[0162] Referring to FIGS. 10 to 14, the direct cooling method will be further described. In each cell array space (M), the longitudinal side of the battery cell assembly (160) faces the side frame (132) and the cross frame (142). In the cell array space (M), the widthwise side of the battery cell assembly (160) faces the front frame (134) and the rear frame (136a, 136b). In the frames (130, 140) surrounding each cell array space (M), a distribution hole (H1) and a recovery hole (H2) are formed to connect each cell array space (M) and the flow paths (132a, 132b, 134a, 134b, 142a, 142b). The positions of the distribution hole (H1) and the recovery hole (H2) can be confirmed in FIGS. 11, 13, and 14.

[0163] Flow paths for cooling fluid are provided within the outer frame (130) and the partition frame (140). Flow paths (132a, 132b) are provided in the side frame (132), flow paths (134a, 134b) are provided in the front frame (134), and flow paths (142a, 142b) are provided in the cross frame (142). When flow paths are provided in the outer frame (130) or the partition frame (140), these flow paths may be connected to each other. In the present embodiment, the side frame (132), the front frame (134), and the cross frame (142) are formed in a hollow rectangular shape, and at least one rib is provided in the height direction to divide the internal space into upper and lower parts, so that the hollow internal space is divided into a plurality of parts in the height direction, so that the flow paths (132a, 132b) are stacked in the height direction in the side frame (132), the flow paths (134a, 134b) are stacked in the height direction in the front frame (134), and the flow paths (142a, 142b) are stacked in the height direction in the cross frame (142), so that a multi-layer structure is formed. The flow paths (132a, 134a, 142a) of the lower hollow portion, i.e., the lower space, can be connected to each other, and the flow paths (132b, 134b, 142b) of the upper hollow portion, i.e., the upper space, can be connected to each other. In this way, a flow path structure can be implemented by using aluminum hollow tubes in the frames (130, 140) to allow cooling fluid to circulate and move throughout the battery pack (100). This allows for cost reduction and improved energy density by eliminating the need for separate heat sinks and related components.

[0164] In this embodiment, the distribution hole (H1) may be formed at a position that connects each cell array space (M) with the upper layer flow paths (132b, 134b, 142b). The recovery hole (H2) may be formed at a position that connects each cell array space (M) with the lower layer flow paths (132a, 134a, 142a). In addition, the distribution hole (H1) and the recovery hole (H2) may be formed on opposite sides.

[0165] The battery pack (100) further includes an inlet port (182) for introducing cooling fluid and a discharge port (184) for discharging cooling fluid. In the present embodiment, the inlet port (182) is provided in the front frame (134) at a position communicating with the upper-layer flow paths (132b, 134b, 142b). The discharge port (184) is provided in the front frame (134) at a position communicating with the lower-layer flow paths (132a, 134a, 142a). The inlet port (182) and the discharge port (184) may be provided in the central portion of the front frame (134) to uniformly distribute and recover the cooling fluid. As another example, the inlet port (182) may be provided at the left end or the right end of the upper flow path (134b) of the front frame (134), and the discharge port (184) may be provided at the end of the lower flow path (134a) below the inlet port (182). As another example, the inlet port (182) may be provided at the left end of the upper flow path (134b) of the front frame (134), and the discharge port (184) may be provided at the right end of the lower flow path (134a). A waterproof component such as an O-ring may be interposed between the assembly surface of the inlet port (182) and the discharge port (184) and the front frame (134).

[0166] If the length of the cooling fluid circulation path is long, the difference in △T between the inlet port (182) and the outlet port (184) may be large. If the temperature difference between battery cells is excessive or continues for a long time, there is a risk of lithium precipitation in the battery cells and a reduction in the battery cell lifespan. Since deteriorated battery cells have a higher frequency of TR and TP occurrence compared to non-deteriorated battery cells when an abnormality occurs, deterioration must be prevented.

[0167] According to the present invention, a cooling path is configured to allow cooling fluid to circulate within the battery pack (100) at the shortest possible distance without a separate heat sink. In the present invention, a liquid immersion cooling method is implemented in which cooling fluid directly circulates within the battery pack (100) through a passage of an aluminum hollow tube.

[0168] Inside the frames (130, 140), the channels (132b, 134b, 142b) for introducing the cooling fluid and the channels (132a, 134a, 142a) for recovering the cooling fluid can be configured in a vertically stacked manner, and the distribution hole (H1) is formed on the side facing the longitudinal side of the battery cell assembly (160) in the frames (130, 140) while communicating with the channels (132b, 134b, 142b) for introducing the cooling fluid, so that the cooling fluid can be introduced to the battery cell assembly (160) along the width direction, which is a shorter distance between the length direction and the width direction. Regarding the battery cell assembly (160), the cooling fluid flows a short distance along the width direction and then, inside the frames (130, 140), communicates with the cooling fluid recovery paths (132a, 134a, 142a) and is recovered directly through the recovery hole (H2) formed on the side facing the longitudinal side of the battery cell assembly (160) in the frames (130, 140).

[0169] In each cell array space (M), the side of the battery cell assembly (160) is surrounded by an outer frame (130) and a partition frame (140). Holes (H1, H2) are arranged in the frames (130, 140) surrounding each cell array space (M) to correspond to each battery cell assembly (160). Cooling fluid introduced from the inlet port (182) is distributed almost equally to all battery cell assemblies (160) through the flow paths (132b, 134b, 142b) of the upper space, and after flowing with a similar flow distance in each cell array space (M), it can be recovered and discharged along an independent discharge path through the flow paths (132a, 134a, 142a) of the lower space. It is possible to configure a cooling fluid that cools one battery cell assembly (160) and a cooling fluid that cools another battery cell assembly (160) to circulate along independent paths without mixing and affecting each other by using a filling member (170) and an adhesive member.

[0170] Thus, according to the present invention, a sealing structure is maintained to prevent leakage of coolant or insulating oil, while still allowing the use of coolant or insulating oil circulated through the vehicle cooling system of an automobile. The battery cells can be directly cooled, and the cooling performance of the battery cells can be enhanced through uniform distribution, rapid recovery, and short-distance flow of the coolant. Furthermore, each battery cell can be uniformly cooled regardless of its location within the battery pack. Consequently, the temperature difference between the cells can be minimized. Therefore, cooling efficiency can be further enhanced by minimizing the temperature difference between each battery cell.

[0171] Referring primarily to FIGS. 13 and 14, in the present embodiment, a cooling fluid is introduced into the frames (130, 140) through an inlet port (182), particularly into a flow path (134b) of an upper layer of the front frame (134). The cooling fluid flows along the flow path (134b) and is distributed to other upper flow paths (132b, 142b) connected to the flow path (134b). The cooling fluid introduced into the upper flow paths (132b, 142b) moves along the flow paths (132b, 142b) and is directly introduced into the battery pack (100) from the longitudinal side of the battery cell assembly (160) through a distribution hole (H1) connected thereto. The introduced cooling fluid cools the battery cell (162) along the width direction of the battery cell assembly (160) and then flows into the recovery hole (H2). The recovery hole (H2) is connected to the lower flow paths (132a, 142a). The cooling fluid entering the recovery hole (H2) flows along the lower flow paths (132a, 142a) and then flows into another lower flow path (134a) connected thereto. A discharge port (184) is provided here, so that the cooling fluid moving along the flow path (134a) can be discharged to the outside of the battery pack (100) through the discharge port (184). By positioning the distribution hole (H1) and the recovery hole (H2) so as to face the longitudinal side of the battery cell assembly (160), the cooling fluid can be brought into contact with the battery cell (162) over a short distance, and the cooling fluid warmed by taking heat away from the battery cell (162) can be quickly recovered. That is, according to the present invention, the cooling efficiency can be maximized by moving the cooling fluid over a short distance.

[0172] To summarize, the cooling fluid introduced into the inlet port (182) moves through the upper channel (134b) of the front frame (134), the upper channel (132b) of the side frame (132) located inside the battery pack (100), and the upper channel (142b) of the cross frame (142). In the present embodiment, it moves to the side where the rear frames (136a, 136b) are located. The cooling fluid is distributed to the first zone (M1), the second zone (M2), the third zone (M3), and the fourth zone (M4) through the distribution holes (H1) that are opened inwardly toward the battery cell assembly (160) in the side frame (132) and the cross frame (142). It is distributed over a short distance in the width direction.

[0173] The cooling fluid distributed to the first zone (M1) moves to the lower flow path (142a) of the right cross frame (142) through the recovery hole (H2) formed on the right side of the right cross frame (142) opposite the inner distribution hole (H1) of the right side frame (132). The cooling fluid distributed to the second zone (M2) moves to the lower flow path (142a) of the middle cross frame (142) through the recovery hole (H2) formed on the right side of the middle cross frame (142) opposite the distribution hole (H1) of the right cross frame (142). The cooling fluid distributed to the third zone (M3) moves to the lower flow path (142a) of the left cross frame (142) through the recovery hole (H2) formed on the right side of the left cross frame (142) opposite the distribution hole (H1) of the middle cross frame (142). The cooling fluid distributed to the fourth zone (M1) moves to the lower flow path (132a) of the left side frame (132) through the recovery hole (H2) formed on the right side of the left side frame (132) opposite the distribution hole (H1) of the left cross frame (142). The cooling fluid that moves to the lower flow paths (132a, 142a) of the side frame (132) and the cross frame (142) moves to the lower flow path (134a) of the front frame (134) and can be discharged to the outside of the battery pack (100) through the discharge port (184) connected thereto.

[0174] In this way, the cooling fluid that cools each zone (M1 to M4) is returned through the recovery hole (H2) that is drilled inside the side frame (132) and the cross frame (142). Since the distribution hole (H1) and the recovery hole (H2) are in different positions and are opposite to each other and are connected to the flow paths of different layers, there is no concern that the fluid flowing into each zone (M1 to M4) and the fluid recovered from each zone (M1 to M2) will be mixed inside the battery pack (100).

[0175] According to the present invention, the cooling fluid is configured to circulate in a unidirectional width direction. The present invention implements a unidirectional flow path circulation structure of a battery pack (100) through immersion cooling without a separate heat sink. Compared to the case where the cooling fluid circulates in a longitudinal direction, the thermal resistance deviation between the inlet port (182) and the outlet port (184) can be reduced. In addition, because it is immersion cooling, the temperature rise of a specific battery cell is suppressed, thereby improving TR / TP reliability.

[0176] In this way, the present invention applies a direct cooling method with excellent cooling heat transfer efficiency. The battery pack (100) of the present invention can receive insulating oil and hydraulic pressure or coolant and pump pressure from the oil pump of a vehicle equipped with the battery pack (100). The insulating oil or water introduced at high pressure into the inlet port (182) is distributed over a short distance to directly cool the battery cells (162). Regardless of the location of the battery cells (162) within the battery pack (100) or the distance from the inlet port (182), it is possible to minimize temperature deviation by implementing uniform cooling performance among the battery cells (162).

[0177] Thereafter, the insulating oil or water accumulated within the battery pack (100) can be discharged and circulated through the discharge port (184). The cooling fluid discharged to the outside can be re-cooled and circulated through the vehicle cooling system of the vehicle and then flowed back into the outside of the battery pack (100). The circulation of the cooling fluid can be achieved by utilizing pump pressure from a pump or the like used in the vehicle cooling system of the vehicle.

[0178] Test results confirmed that as the cooling fluid path length increased, the temperature difference between battery cells tended to worsen. During rapid charging, high-power, and extended use, the temperature difference between battery cells became more severe, leading to abnormal defects.

[0179] In the present invention, the cooling fluid enters from the inlet port (182) and the cooling fluid circulation distance to the discharge port (184) is implemented as short as possible so that the thermal resistance between the battery cells (162) is maintained uniformly, thereby minimizing the temperature difference between the battery cells (162).

[0180] In this way, according to the present invention, a battery pack (100) having a cell-to-pack type structure is provided, which implements a waterproof and sealed structure through structural simplification and improves cooling efficiency through application of an immersion cooling method. An efficient cooling path configuration is possible in which a cooling fluid circulates throughout the battery pack (100) from the inlet port (182) to the outlet port (184) without a separate heat sink. Assembly complexity / assembly efficiency is greatly improved due to a reduction in the number of components required for configuring the cooling line.

[0181] FIG. 15 is a drawing for explaining a vehicle according to one embodiment of the present invention.

[0182] Meanwhile, the present invention can provide a vehicle (V) characterized by including a battery pack (1, 100) according to the above-described embodiment. That is, the battery pack (1, 100) according to the present invention can be applied to a vehicle such as an electric vehicle or a hybrid vehicle. For example, the battery pack (1, 100) can be installed in a body frame under a vehicle seat or in a trunk space. The vehicle (V) includes a four-wheeled vehicle and a two-wheeled vehicle. The vehicle (V) operates by receiving power from the battery pack (1, 100) according to one embodiment of the present invention.

[0183] It goes without saying that the battery pack (1, 100) according to the present invention can be applied to ESS (Energy Storage System) and various electrical devices in addition to automobiles. In this way, devices, apparatus, and equipment equipped with the battery pack (1, 100), such as the automobile (V) according to the embodiment of the present invention, include the aforementioned battery pack (1, 100), and can be implemented while having all the advantages of the aforementioned battery pack (1, 100).

[0184] In other words, the vehicle (V) includes a battery pack (1, 100), which, as described above, has excellent cooling performance and improved waterproof reliability. Therefore, the vehicle (V) including the battery pack is safe and easy to operate.

[0185] In addition, the battery pack (100) can efficiently discharge high-temperature gases and flames, thereby ensuring the safety and reliability of the battery pack (100) and extending the flame movement path. Accordingly, even if a problem occurs with the battery pack (100) while driving the vehicle (V), stability is maintained. In addition, since the battery pack (100) has excellent stability and can be used for a long time, the vehicle (V) including it is safe and easy to operate.

[0186] In this way, the vehicle (V) including the battery pack (1, 100) of the present invention has improved safety and durability.

[0187] In particular, the battery pack (100) can eliminate the risk of cracks occurring at the interface of the potting resin or inside the potting resin layer when subjected to vibration / shock, thereby further improving waterproof reliability. Therefore, the battery pack (100) is very advantageous for application to automobiles (V) that are frequently exposed to external vibrations.

[0188] As is well known, ESS stores renewable energy such as solar and wind power, which are difficult to produce at desired times, in advance and allows them to be used when needed. To configure a standalone system that stores hundreds of kWh or more of power, a battery pack (1, 100) according to the present invention can be used to store power in such ESS. As described above, the battery pack (1, 100) according to the present invention has excellent cooling performance and reliable waterproof performance, and can quickly discharge high-temperature gas or flames generated by a thermal event occurring in the battery cells (62, 162) to the outside of the pack housing (10, 110). Therefore, even if a problem occurs in some battery packs, the stability of the ESS is maintained and the spread of fire can be prevented.

[0189] As described above, although the present invention has been described by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0190] [Explanation of symbols]

[0191] 1, 100: Battery pack 10, 110: Pack housing

[0192] 20, 120: Bottom plate 122: Home plate

[0193] 124: Plastic supporter 126: GF sheet

[0194] 128: Cell Supporter 30, 130: Outer Frame

[0195] 32, 132: Side frame

[0196] 32a, 32b, 34a, 34b, 42a, 42b, 132a, 132b, 134a, 134b, 142a, 142b: Euro

[0197] 34, 134: Front frame 36, 136a, 136b: Rear frame

[0198] 40, 140: Partition frame 42: Cross frame

[0199] 44: Center frame 60, 160: Battery cell assembly

[0200] 62, 162: Battery cell 164: Holder

[0201] 165: Adhesive member 170: Filling member

[0202] 180: Relay box 82, 182: Inlet port

[0203] 84, 184: exhaust port 90, 190: top frame

[0204] 192: Adhesive 195: Relay device cover

[0205] H1: Distribution hole H2: Recovery hole

[0206] M: Cell array space V: Car

Claims

1. Pack housing including bottom plate, outer frame and partition frame; and comprising a plurality of battery cell assemblies housed in the pack housing; Inside the above outer frame and partition frame, a flow path for cooling fluid and a distribution hole and a recovery hole connected to the flow path are provided. A battery pack in which the cooling fluid flows toward the battery cell assembly to directly cool the battery cells within the battery cell assembly.

2. A battery pack according to claim 1, characterized in that at least a portion of the outer frame and the partition frame are hollow metal tubes.

3. A battery pack characterized in that in the first paragraph, at least a part of the outer frame and the partition frame includes a hollow portion, the hollow portions of the outer frame and the partition frame are connected to form the flow path, and the flow path has a structure of at least two layers stacked in the vertical direction.

4. A battery pack according to claim 1, wherein the battery cell assembly comprises a plurality of cylindrical secondary batteries arranged in rows and columns and standing vertically as the battery cells, the longitudinal dimension of the battery cell assembly being larger than the width dimension, and the longitudinal direction of the battery cell assembly being positioned along the front-rear direction of the battery pack.

5. In the fourth paragraph, the outer frame includes a pair of side frames each arranged on the left and right sides of the bottom plate, and a front frame and a rear frame each arranged on the front and rear sides, The above partition frame includes a cross frame arranged in the front-back direction on the bottom plate or a center frame arranged in the left-right direction on the bottom plate, A battery pack characterized in that the internal space of the pack housing is divided into a plurality of cell array spaces by the partition frame, and the battery cell assembly is individually installed in each of the cell array spaces.

6. In the fifth paragraph, the side frame, the front frame, and the cross frame are formed in a hollow rectangular shape, and at least one rib is provided in the height direction to divide the internal space into upper and lower parts, so that the hollow internal space is divided into a plurality of parts in the height direction, thereby providing a multi-layer structure in which the flow paths are stacked in the height direction, and the flow paths of the lower layers of the side frame, the front frame, and the cross frame are connected to each other, and the flow paths of the upper layers of the side frame, the front frame, and the cross frame are connected to each other. A battery pack characterized in that.

7. A battery pack characterized in that, in the 6th paragraph, the distribution hole is formed at a position that connects each of the cell array spaces with the upper layer flow paths, and the recovery hole is formed at a position that connects each of the cell array spaces with the lower layer flow paths.

8. A battery pack characterized in that, in the 7th paragraph, an inlet port for introducing the cooling fluid is formed at a position that connects the upper layer's flow paths, and a discharge port for discharging the cooling fluid is provided at a position that connects the lower layer's flow paths.

9. A battery pack according to claim 8, characterized in that the inlet port and the outlet port are provided in the front frame.

10. In the 8th paragraph, the distribution hole is located on the inside of the right side frame and the left side of the cross frame, and the recovery hole is located on the right side of the cross frame and the inside of the left side frame, so that the cooling fluid is directly introduced into each of the cell array spaces from the longitudinal side of the battery cell assembly through the distribution hole and recovered from the longitudinal side of the battery cell assembly through the recovery hole. A battery pack.

11. In the fifth paragraph, a battery pack characterized in that the outer frame and the partition frame surrounding the cell array space have the distribution holes and the recovery holes arranged to correspond to each of the battery cell assemblies, and the cooling fluid in the passage is distributed to each of the cell array spaces and recovered and discharged along an independent discharge path.

12. In the first paragraph, the pack housing includes an upper opening, A battery pack further characterized by including a filling member sealing the upper opening.

13. In paragraph 12, A battery pack characterized in that the above-mentioned filling material is made of potting resin.

14. A battery pack characterized in that it further includes a top frame that is bonded and connected with an upper surface of the outer frame through an adhesive in the 12th paragraph.

15. In the fourth paragraph, the battery cell includes a vent portion at the bottom, The above bottom plate includes a press-formed groove portion to allow the battery cell assembly to be seated therein, Further comprising a plastic supporter on the above home portion, A battery pack characterized in that gas or flame ejected through the vent part moves along a venting path defined by the plastic supporter within the groove part.

16. In the 12th paragraph, the battery cell assembly is configured to maintain a dense arrangement of the battery cells. A holder for storing the lower part of the battery cell; A middle frame supporting an upper portion of the battery cell than the position supported by the holder; and A battery pack characterized by including an adhesive member that fixes the holder and the battery cell.

17. In paragraph 16, the holder, A main body having a plurality of receiving grooves formed parallel to each other so that the battery cells can be inserted respectively; and A battery pack characterized by including a spacer provided between the above-mentioned receiving grooves and configured to maintain a gap between the battery cells.

18. A battery pack characterized in that, in the 16th paragraph, a cooling passage space is formed between the holder and the middle frame to allow the cooling fluid to be filled, and the middle frame isolates the cooling fluid from the filling member.

19. A vehicle comprising a battery pack according to any one of claims 1 to 18.

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