Immersion cooling battery pack

Abstract

The present invention discloses an immersion-cooled battery pack capable of preventing fire by maintaining a battery module housed in a lower case at a state below its ignition point, by connecting a lower case and an upper cover with a leak-prevention connection portion to prevent the leakage of insulating fluid between the lower case and the upper cover. The disclosed immersion-cooled battery pack is characterized by comprising: a lower case having an open upper portion and an inlet portion guiding the inflow of insulating fluid on its periphery; a battery module accommodated in the lower case to be immersed in the insulating fluid flowing into the inlet portion; an upper cover covering the open portion of the lower case and having an outlet portion guiding the discharge of insulating fluid on its periphery; a leak-prevention connection portion connecting the lower case and the upper cover to prevent the leakage of insulating fluid between the lower case and the upper cover; and a sealing reinforcement portion provided on the upper cover to reinforce the sealing of the leak-prevention connection portion when the upper cover is connected to the lower case by the leak-prevention connection portion.

Description

Technology Field

[0001] The present invention relates to a liquid-immersion cooling type battery pack, and more specifically, to a liquid-immersion cooling type battery pack that can prevent fire by maintaining a battery module housed in a lower case at a state below the ignition point, by reinforcing the sealing of the leak-prevention connection part when connecting the lower case and the upper cover so that the leak-prevention connection part prevents the leakage of insulating fluid between the lower case and the upper cover. Background Technology

[0003] Generally, electric vehicles are vehicles that operate using electrical energy output from a battery. Since these electric vehicles use a battery formed as a single pack of multiple rechargeable and dischargeable cells as a power source, they have the advantage of producing no exhaust gas and very little noise.

[0004] As electric vehicles utilize electric energy, battery performance directly affects the vehicle's performance; therefore, a battery management system is required to measure the voltage of each battery cell, the voltage and current of the entire battery, efficiently manage the charging and discharging of each cell, and determine whether each battery cell is degraded to ensure maximum performance.

[0005] Recently, the use of lithium-ion batteries in such electric vehicles has been increasing. As a type of rechargeable lithium-ion battery, it features a multilayer structure comprising a positive electrode activated by various mixed oxides or olivine, a negative electrode activated by specific carbons, and a separator immersed in an organic electrolyte. In other words, during charging, lithium in the positive electrode is ionized and moves layer by layer toward the negative electrode, and during discharging, the ions move to the positive electrode and return to their original compounds.

[0006] As such, since the battery is the most significant factor affecting the performance of electric vehicles, battery capacity must be increased to achieve high speeds and long driving ranges, and consequently, stable charging and discharging functions are required. However, heat is generated by the chemical reactions of electrons in electric vehicle batteries, and this generated heat causes a degradation in battery performance and lifespan. Furthermore, if a fire occurs due to battery overheating, there is a problem that the entire vehicle could be lost due to thermal runaway within the battery pack's internal cells.

[0007] Therefore, there is a need to improve this.

[0008] A related background technology is Korean Patent Publication No. 10-2024-0002040 (published Jan. 4, 2024, Title: Battery Thermal Management System for Electric Vehicles). The problem to be solved

[0010] The present invention was created out of the above necessity, and aims to provide an immersion-cooled battery pack capable of preventing fire by maintaining the battery module housed in the lower case at a state below the ignition point, by reinforcing the sealing of the leak-prevention connection part when connecting the lower case and the upper cover so that the leak-prevention connection part prevents the leakage of insulating fluid between the lower case and the upper cover. means of solving the problem

[0012] To achieve the above-mentioned objective, a liquid-immersion cooling type battery pack according to one embodiment of the present invention comprises: a lower case having an open upper portion and an inlet pipe portion that guides the inflow of insulating fluid on its periphery; a battery module accommodated in the lower case to be immersed in the insulating fluid introduced through the inlet pipe portion; an upper cover covering the open portion of the lower case and having an outlet pipe portion that guides the discharge of insulating fluid on its periphery; a leak-prevention connection portion connecting the lower case and the upper cover to prevent the leakage of insulating fluid between the lower case and the upper cover; and a sealing reinforcement portion provided on the upper cover to reinforce the sealing of the leak-prevention connection portion when the upper cover is connected to the lower case by the leak-prevention connection portion.

[0013] The battery module is characterized by comprising a plurality of first battery cells arranged in a row along the length direction of the lower case and spaced apart along the width direction of the lower case, second battery cells arranged in a row along the length direction of the lower case and spaced apart along the width direction of the lower case so as to be adjacent to the first battery cells while staggered, a first integration fixing part that fixes the upper side of the first battery cell and the second battery cell so as to be integrated, and a second integration fixing part that fixes the lower side of the first battery cell and the second battery cell so as to be integrated.

[0014] The first integrated fixing part is characterized by including a plurality of first fitting holders that are collectively fitted to an adjacent pair of the first battery cells and an adjacent pair of the second battery cells and are mutually slidably connected, and a pair of connecting members that connect the first fitting holders arranged along the width direction of the lower case to be integrated.

[0015] A plurality of first rail grooves and a plurality of first slide rails are formed spaced apart on the circumferential surface of the first fitting holder, and the connecting member is characterized in that a first connecting slide rail that is slidably fitted into the first rail groove and a plurality of first connecting rail grooves that are slidably inserted into the first slide rail are formed spaced apart on the portion facing the circumferential surface of the first fitting holder.

[0016] The second integrated fixing part is characterized by including a pair of outer fitting holders that are fitted into the first battery cell and the second battery cell arranged along the length direction of the lower case among the first battery cell and the second battery cell, and a plurality of second fitting holders that are fitted collectively between an adjacent pair of the first battery cells and an adjacent pair of the second battery cells between the outer fitting holders and are connected to each other in a slidingly separable manner.

[0017] The circumferential surface of the second fitting holder is formed with a plurality of second rail grooves and a plurality of second slide rails spaced apart, and the outer fitting holder is characterized by having a second connecting slide rail that slides into the second rail grooves in a sliding manner and a plurality of second connecting rail grooves that slide into the second slide rails spaced apart, formed in a portion facing the circumferential surface of the second fitting holder.

[0018] The above-described leak prevention connection part is characterized by including a support flange part formed protruding along the upper circumference direction of the lower case, a seating flange part formed protruding along the lower circumference direction of the upper cover to be seated on the support flange part, a sealing pad interposed between the support flange part and the seating flange part, and a contact fixing part that fixes the support flange part and the seating flange part so that both sides of the sealing pad are in close contact with the support flange part and the seating flange part.

[0019] The above-described close-fitting portion is characterized by including a plurality of through-hole portions formed spaced apart and penetrating the support flange portion, a communication hole portion formed penetrating the sealing pad to communicate with the through-hole portions, a fastening groove portion formed recessed in the seating flange portion to communicate with the communication hole portions, and a fastening bolt inserted into the through-hole portions to be fastened to the fastening groove portions.

[0020] The sealing pad is characterized by having, on each side in the thickness direction thereis a first contact protrusion formed protruding with a diameter larger than the diameter of the communication hole portion centered on the communication hole portion, and a plurality of second contact protrusions formed protruding spaced apart along the circumference direction of the sealing pad and connected to the first contact protrusion portion.

[0021] The sealing reinforcement member is characterized by including an extension receiving portion formed to extend into the upper cover so as to be received inside the lower case, and an elastic sealing member that is fixedly fitted to the end of the extension receiving portion and elastically presses the inner surface of the lower case. Effects of the invention

[0023] According to the liquid immersion cooling type battery pack of the present invention, when connecting the lower case and the upper cover, the sealing reinforcement part has a structure that reinforces the sealing of the leakage prevention connection part so as to prevent the leakage of insulating fluid between the lower case and the upper cover, thereby allowing the battery module housed in the lower case to be maintained at a state below the ignition point to prevent fire. Brief explanation of the drawing

[0025] FIG. 1 is a perspective view illustrating an immersion-cooled battery pack according to one embodiment of the present invention. FIG. 2 is an exploded perspective view illustrating an immersion-cooled battery pack according to one embodiment of the present invention. FIG. 3 is an exploded perspective view showing a battery module in an immersion-cooled battery pack according to one embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating a leakage prevention connection part and a sealing reinforcement part in a liquid immersion cooling type battery pack according to one embodiment of the present invention. FIG. 5 is a cross-sectional view illustrating a state in which a battery module is immersed in an insulating fluid in a liquid-immersion cooling type battery pack according to one embodiment of the present invention. Specific details for implementing the invention

[0026] Hereinafter, an embodiment of an immersion-cooled battery pack according to the present invention will be described with reference to the attached drawings. In this process, the thickness of lines or the size of components shown in the drawings may be exaggerated for clarity and convenience of explanation.

[0027] Furthermore, the terms described below are defined in consideration of their functions in the present invention, and these may vary depending on the intent or practice of the user or operator. Therefore, the definitions of these terms should be based on the content throughout this specification.

[0029] FIG. 1 is a perspective view illustrating an immersion-cooled battery pack according to an embodiment of the present invention, FIG. 2 is an exploded perspective view illustrating an immersion-cooled battery pack according to an embodiment of the present invention, FIG. 3 is an exploded perspective view illustrating a battery module in an immersion-cooled battery pack according to an embodiment of the present invention, FIG. 4 is a cross-sectional view illustrating a leakage prevention connection part and a sealing reinforcement part in an immersion-cooled battery pack according to an embodiment of the present invention, and FIG. 5 is a cross-sectional view illustrating a state in which a battery module is immersed in an insulating fluid in an immersion-cooled battery pack according to an embodiment of the present invention.

[0031] As illustrated in FIGS. 1 to 5, a liquid-immersion cooling type battery pack according to one embodiment of the present invention includes a lower case (100), a battery module (200), an upper cover (300), a leakage prevention connection part (400), and a sealing reinforcement part (500).

[0032] The lower case (100) has an open upper side and is equipped with an inlet pipe section (110) that guides insulating fluid to flow into the periphery.

[0033] This lower case (100) serves to accommodate the insulating fluid and the battery module (200) so that the battery module (200) is immersed in the insulating fluid introduced into the inlet pipe (110) to cool the battery module (200), while also providing a space for the upper cover (300) to be installed.

[0034] And, the battery module (200) is housed in the lower case (100) so as to be submerged in the insulating fluid introduced into the inlet pipe (110).

[0035] The battery module (200) includes a plurality of first battery cells (210) arranged in a row along the length direction of the lower case (100) and spaced apart along the width direction of the lower case (100), second battery cells (220) arranged in a row along the length direction of the lower case (100) and spaced apart along the width direction of the lower case (100) so as to be adjacent to the first battery cells (210) in an alternating manner, a first integration fixing part (230) that fixes the upper side of the first battery cells (210) and the second battery cells (220) so as to be integrated, and a second integration fixing part (240) that fixes the lower side of the first battery cells (210) and the second battery cells (220) so as to be integrated.

[0036] At this time, a bus bar (250) that is mutually electrically connected may be arranged to contact each other on both axial sides of the first battery cell (210) and the second battery cell (220) arranged adjacently along the length direction of the lower case (100).

[0037] Here, the first integrated fixing part (230) is inserted collectively into an adjacent pair of first battery cells (210) and an adjacent pair of second battery cells (220), and includes a plurality of first insertion holders (231) that are mutually slide-separably connected, and a pair of connecting members (232) that are connected to the first insertion holders (231) arranged along the width direction of the lower case (100) among the first insertion holders (231) to integrate the first insertion holders (231).

[0038] Additionally, a plurality of first rail grooves (231a) and a plurality of first slide rails (231b) may be formed spaced apart on the circumferential surface of the first fitting holder (231). That is, the first rail groove (231a) of the first fitting holder (231) is slidably fitted into the first slide rail (231b) of the adjacent first fitting holder (231), and the first slide rail (231b) of the first fitting holder (231) is slidably inserted into the first rail groove (231a) of the adjacent first fitting holder (231).

[0039] Additionally, a first stopper member (231C) may be formed protruding from the first insertion holder (231) to restrict insertion by engaging with the upper ends of the first battery cell (210) and the second battery cell (220).

[0040] The connecting member (232) may be formed with a plurality of spaced-apart first connecting slide rails (232a) that slide into the first rail groove (231a) of the first fitting holder (231) in a sliding manner on a portion facing the circumferential surface of the first fitting holder (231), and first connecting rail grooves (232b) that slide into the first slide rail (231b) of the first fitting holder (231).

[0041] The second integrated fixing part (240) includes a pair of outer fitting holders (241) that are fitted into the first battery cell (210) and the second battery cell (220) arranged along the length direction of the lower case (100) among the first battery cell (210) and the second battery cell (220), and a plurality of second fitting holders (242) that are fitted collectively between an adjacent pair of the first battery cell (210) and an adjacent pair of the second battery cell (220) between the outer fitting holders (241) and are connected so as to be slide-separable from each other.

[0042] At this time, a plurality of second rail grooves (242a) and a plurality of second slide rails (242b) may be formed spaced apart on the circumferential surface of the second fitting holder (242). That is, the second rail groove (242a) of the second fitting holder (242) is slidably fitted into the second slide rail (242b) of the adjacent second fitting holder (242), and the second slide rail (242b) of the second fitting holder (242) is slidably inserted into the second rail groove (231a) of the adjacent second fitting holder (242).

[0043] Additionally, a second stopper member (242C) may be formed protruding from the second insertion holder (242) to restrict insertion by engaging with the lower ends of the first battery cell (210) and the second battery cell (220).

[0044] In the outer fitting holder (241), a second connecting slide rail (241a) that slides into the second rail groove (242a) of the second fitting holder (242) and a second connecting rail groove (241b) that slides into the second slide rail (242b) of the second fitting holder (242) may be formed spaced apart in a portion facing the circumferential surface of the second fitting holder (242).

[0045] Accordingly, the first battery cell (210) and the second battery cell (220) can be increased or decreased in the width and length directions of the battery module (200) by the first integrated fixing part (230) and the second integrated fixing part (240), so that the battery module (200) can be set to various capacities.

[0046] At this time, a plurality of spaced-out mounting members (243) may be connected to the outer fitting holder (242) so that the first battery cell (210) and the second battery cell (220) are spaced apart along the length direction and seated on the lower case (100).

[0047] Thus, insulating fluid can flow between the first battery cell (210) and the lower case (100) and between the second battery cell (220) and the lower case (100), thereby improving the cooling efficiency of the first battery cell (210) and the second battery cell (220).

[0048] And, the upper cover (300) covers the open portion of the lower case (100) and is equipped with a discharge pipe portion (310) that guides the discharge of insulating fluid on the periphery.

[0049] This upper cover (300) is formed with an open lower side to accommodate the upper side of the battery module (200) and simultaneously performs the function of discharging insulating fluid that has flowed into the interior of the lower case (100).

[0050] Meanwhile, the leakage prevention connection part (400) is configured to connect the lower case (100) and the upper cover (300) so as to prevent the leakage of insulating fluid between the lower case (100) and the upper cover (300).

[0051] Specifically, the leak prevention connection part (400) includes a support flange part (410) formed protruding along the upper circumference direction of the lower case (100), a seating flange part (420) formed protruding along the lower circumference direction of the upper cover (300) to be seated on the support flange part (410), a sealing pad (430) interposed between the support flange part (410) and the seating flange part (420) to seal the gap between the support flange part (410) and the seating flange part (420), and a sealing fixing part (440) that fixes the support flange part (410) and the seating flange part (420) so that both sides in the thickness direction of the sealing pad (430) are in close contact with the support flange part (410) and the seating flange part (420).

[0052] Additionally, the close-fitting fixing part (440) includes a plurality of through-hole portions (441) formed spaced apart through the support flange portion (410), a communication hole portion (442) formed through the sealing pad (430) to communicate with the through-hole portions (441), a fastening groove portion (443) formed recessed in the seating flange portion (420) to communicate with the communication hole portions (442), and a fastening bolt (444) inserted into the through-hole portions (441) to be fastened to the fastening groove portions (443).

[0053] That is, when one side of the communication hole portion (442) aligns with the through hole portion (441) and the other side of the communication hole portion (442) aligns with the fastening groove portion (443), and the fastening bolt (444) passes through the through hole portion (441) and the communication hole portion (442) and is fastened to the fastening groove portion (443), the sealing pad (430) is pressed on both sides in the thickness direction against the support flange portion (410) and the seating flange portion (420), thereby preventing a gap from being formed between the support flange portion (410) and the seating flange portion (420).

[0054] At this time, the sealing pad (430) may be provided with a first contact protrusion (431) formed protruding with a diameter larger than the diameter of the communication hole (442) centered on the communication hole (442), and a plurality of second contact protrusions (432) formed protruding spaced apart along the circumference of the sealing pad (430) and connected to the first contact protrusion (432), each on both sides in the thickness direction.

[0055] Thus, when both sides of the sealing pad (430) in the thickness direction are pressed against the support flange portion (410) and the seating flange portion (420), the first contact protrusion portion (431) and the second contact protrusion portion (432) can seal the area where the support flange portion (410) and the sealing pad (430) come into contact and the area where the seating flange portion (420) and the sealing pad (430) come into contact in multiple ways, thereby enhancing the performance of the sealing pad (430).

[0056] Additionally, the sealing reinforcement part (500) is provided on the upper cover (300), and is configured to reinforce the sealing of the leakage prevention connection part (400) when the upper cover (300) is connected to the lower case (100) by the leakage prevention connection part (400).

[0057] The sealing reinforcement member (500) may include an extension receiving member (510) that is extended and formed on the upper cover (300) to be received inside the lower case (100), and an elastic sealing member (520) that is fixedly fitted to the end of the extension receiving member (510) to elastically press the inner surface of the lower case (100).

[0058] At this time, it is preferable that the portion of the elastic sealing member (520) facing the inner surface of the lower case (100) be formed at an angle such that the thickness decreases as it goes toward the end of the extension receiving portion (510).

[0059] That is, when the upper cover (300) is seated on the lower case (100) to cover the open portion of the lower case (100), the extension receiving portion (510) is received into the interior of the lower case (100), and the elastic sealing member (520) is supported by the extension receiving portion (510) and elastically adheres to the inner surface of the lower case (100).

[0060] Accordingly, when the lower case (100) and the upper cover (300) are connected through the leakage prevention connection part (400), the sealing reinforcement part (500) reinforces the sealing performance of the leakage prevention connection part (400), thereby further improving the airtightness of the insulating fluid.

[0062] Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom.

[0063] Therefore, the true technical scope of protection of the present invention should be determined by the patent claims.

[0065] This achievement (intellectual property rights) is the Future Vehicle Battery System Core Component Development Support Project, which was carried out with the support of the Gyeongbuk Hybrid Parts Research Institute in 2024.

[0066] Project Management (Specialized) Agency Name: Gyeongbuk Hybrid Parts Research Institute

[0067] Research Project Name: Support for Development of Core Components for Future Vehicle Battery Systems

[0068] Research Project Title: Development of OTA-based High-Life Battery Management System (BMS) and Battery Module for EV Mobility

[0069] Organizer: Youngjin Co., Ltd.

[0070] Project Period: 2024.03.01 ~ 2024.11.30 Explanation of the symbols

[0072] 100: Lowercase 110: Inflow pipe 200: Battery module 210: First battery cell 220: 2nd battery cell 230: 1st integrated fixing part 231: First insert holder 232: Connecting member 240: Second integrated fixing part 241: Outer insert holder 242: Second insert holder 243: Spaced seating member 250: Busbar 300: Upper cover 310: Discharge pipe section 400: Outflow prevention connection section 410: Support Plan Branch 420: Settlement Plan Branch 430: Sealing pad 431: First contact protrusion 432: Second contact projection 440: Contact fixing part 441: Through hole section 442: Chimney hole section 443: Fastening groove 444: Fastening bolt 500: Sealing reinforcement part 510: Extension receiving member 520: Elastic sealing member

Claims

Claim 1 A lower case having an open upper portion and an inlet pipe portion on its periphery that guides the inflow of insulating fluid; a battery module accommodated in the lower case to be submerged in the insulating fluid flowing into the inlet pipe portion; an upper cover covering the open portion of the lower case and having an outlet pipe portion on its periphery that guides the discharge of insulating fluid; and a leakage prevention connection portion connecting the lower case and the upper cover to prevent leakage of insulating fluid between the lower case and the upper cover. and a sealing reinforcement part provided on the upper cover to reinforce the sealing of the leakage prevention connection part when the upper cover is connected to the lower case by the leakage prevention connection part; wherein the battery module comprises a plurality of first battery cells arranged in a row along the length direction of the lower case and spaced apart along the width direction of the lower case, a second battery cell arranged in a row along the length direction of the lower case and spaced apart along the width direction of the lower case so as to be adjacent to the first battery cell while staggered, a first integration fixing part that fixes the upper side of the first battery cell and the second battery cell so as to be integrated, and a second integration fixing part that fixes the lower side of the first battery cell and the second battery cell so as to be integrated, wherein the first battery cell and the second battery cell are spaced apart from the lower case in the second integration fixing part. A liquid-immersion cooling type battery pack characterized in that a spacing member is connected to allow an insulating fluid to flow between the first battery cell and the lower case and between the second battery cell and the lower case, and the sealing reinforcement member includes an extension receiving portion formed extending from the upper cover to be received inside the lower case, and an elastic sealing member that is fixedly fitted to the end of the extension receiving portion to elastically press the inner surface of the lower case, wherein the portion of the elastic sealing member facing the inner surface of the lower case is formed at an angle such that the thickness decreases as it extends toward the end of the extension receiving portion. Claim 2 delete Claim 3 A liquid-immersion cooling type battery pack according to claim 1, wherein the first integrated fixing part comprises: a plurality of first fitting holders that are collectively fitted to an adjacent pair of the first battery cells and an adjacent pair of the second battery cells and are mutually slidably connected; and a pair of connecting members that connect the first fitting holders arranged on the outer edge along the width direction of the lower case to be integrated. Claim 4 A liquid-immersion cooling type battery pack according to claim 3, wherein a plurality of first rail grooves and a plurality of first slide rails are formed spaced apart on the circumferential surface of the first fitting holder, and the connecting member is formed spaced apart on the portion facing the circumferential surface of the first fitting holder, wherein a first connecting slide rail that is slidably fitted into the first rail groove and a plurality of first connecting rail grooves that are slidably inserted into the first slide rails. Claim 5 A liquid-immersion cooling type battery pack according to claim 1, wherein the second integrated fixing part comprises: a pair of outer fitting holders fitted onto the first battery cell and the second battery cell arranged on the outer side along the longitudinal direction of the lower case among the first battery cell and the second battery cell; and a plurality of second fitting holders that are fitted collectively between an adjacent pair of the first battery cells and an adjacent pair of the second battery cells between the outer fitting holders and are connected to each other so as to be slide-separable. Claim 6 A liquid-immersion cooling type battery pack according to claim 5, wherein a plurality of second rail grooves and a plurality of second slide rails are formed spaced apart on the circumferential surface of the second fitting holder, and a second connecting slide rail that slides into the second rail grooves and a plurality of second connecting rail grooves that slide into the second slide rails are formed spaced apart on the outer fitting holder in a portion facing the circumferential surface of the second fitting holder. Claim 7 In claim 1, the leakage prevention connection part comprises: a support flange part formed protruding along the upper circumferential direction of the lower case; a seating flange part formed protruding along the lower circumferential direction of the upper cover to be seated on the support flange part; a sealing pad interposed between the support flange part and the seating flange part; and a contact fixing part that fixes the support flange part and the seating flange part so that both sides of the sealing pad are in close contact with the support flange part and the seating flange part; characterized in that it comprises an immersion cooling type battery pack. Claim 8 In claim 7, the contact fixing portion comprises: a plurality of through-hole portions formed spaced apart and penetrating the support flange portion; a communication hole portion formed penetrating the sealing pad to communicate with the through-hole portions; a fastening groove portion formed recessed in the seating flange portion to communicate with the communication hole portions; and a fastening bolt inserted into the through-hole portions to be fastened to the fastening groove portions; characterized in that it is an immersion-cooled battery pack. Claim 9 A liquid-immersion cooling type battery pack according to claim 8, characterized in that on both sides of the thickness direction of the sealing pad, there are provided a first contact protrusion formed protruding with a diameter larger than the diameter of the communication hole centered on the communication hole, and a plurality of second contact protrusions formed protruding spaced apart along the circumference direction of the sealing pad and connected to the first contact protrusion. Claim 10 delete

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