Battery assembly for preventing thermal runway

Abstract

A battery assembly for preventing thermal runaway according to the present invention comprises: a plurality of battery cells; a battery pack which defines an accommodation space for accommodating the plurality of battery cells electrically connected to each other and protects the plurality of battery cells from the outside; a fire-extinguishing coolant filled in the battery pack and including any one of a liquid non-conductive aqueous material and a gel-phase non-conductive aqueous mixture in which a non-conductive aqueous material and a superabsorbent resin are mixed; and a coolant supply unit selectively coupled to and decoupled from the battery pack and configured to supply the non-conductive aqueous material into the battery pack on the basis of the level of the fire-extinguishing coolant filled in the battery pack.

Description

Battery assembly for preventing thermal runaway

[0001] The present invention relates to a battery assembly for preventing thermal runaway, and more specifically, to a battery assembly for preventing thermal runaway that minimizes heat transfer to adjacent battery cells when a fire occurs in at least one of a plurality of battery cells.

[0002] Recently, there has been an increase in the use of secondary batteries, which are relatively more flexible than primary batteries and have a longer charge / discharge cycle, to supply electrical energy to smart devices such as smartphones, electric vehicles that have replaced fossil fuels, and unmanned carriers or autonomous robots used in the logistics industry, instead of primary batteries that cannot be recharged.

[0003] Here, high-capacity secondary batteries capable of charging and discharging large amounts of electrical energy are used in electric vehicles, unmanned transport vehicles, or autonomous robots to increase operating time or driving distance compared to smart devices.

[0004] These secondary batteries largely include ternary batteries in which the cathode material is composed of nickel-cobalt-manganese (NCM) or nickel-cobalt-aluminum (NCA), and lithium iron phosphate batteries (LFP) in which the cathode material is composed of lithium iron phosphate. Although there is a difference in relative density between ternary batteries and lithium iron phosphate batteries, there is a risk of explosion due to thermal runaway in the event of a fire.

[0005] Generally, secondary batteries consist of multiple battery cells, and multiple battery cells are housed in a battery pack. Battery packs are used in single or multiple numbers depending on their capacity. For example, dozens of battery packs may be used in electric vehicles, and battery packs may be used in single or multiple numbers in autonomous robots.

[0006] Meanwhile, when a fire occurs in at least one of the multiple battery cells contained in the battery pack, heat transfer occurs to the battery cell adjacent to the ignition point, and a thermal runaway phenomenon may occur in which multiple battery cells explode in succession.

[0007] However, since the progression time for the successive explosion of individual battery cells during a battery thermal runaway is very rapid, there is an increasing need to slow down or block the speed of the thermal runaway to allow time for firefighting equipment or fire department support to arrive.

[0008] The objective of the present invention is to provide a battery assembly for preventing thermal runaway with an improved structure that can prevent thermal runaway of adjacent battery cells when a fire occurs in at least one of a plurality of battery cells.

[0009] The means for solving the above problem is provided by a battery assembly for preventing thermal runaway, characterized in that it comprises, according to the present invention, a plurality of battery cells, a battery pack that forms a receiving space for electrically connected plurality of battery cells and protects the plurality of battery cells from the outside, a fire suppressant filled inside the battery pack comprising one of a liquid non-conductive aqueous material and a gel-like non-conductive aqueous mixture in which the non-conductive aqueous material and a superabsorbent resin are mixed, and a coolant supply unit that is selectively coupled to and separated from the battery pack and supplies the non-conductive aqueous material into the battery pack based on the water level of the fire suppressant filled inside the battery pack.

[0010] The above coolant supply unit is coupled to the battery pack based on the decrease in the water level due to the evaporation of moisture from the fire extinguishing coolant filled inside the battery pack, and can supply a non-conductive aqueous material into the battery pack through capillary action.

[0011] It may further include a water level sensor disposed inside the battery pack to detect the water level of the fire extinguishing coolant.

[0012] The battery pack comprises a box-shaped battery cell receiving portion that forms an opening for the battery cell to be inserted and removed from the upper side and a receiving space for receiving the battery cell, and a cover portion that selectively opens and closes the opening, and the cover portion may have an injection portion formed therein that communicates with the receiving space and injects the fire extinguishing coolant into the receiving space.

[0013] The above-described battery assembly for preventing thermal runaway may further include an adsorption portion disposed along the inner perimeter of the battery cell receiving portion to absorb shock transmitted from the outside to the battery cell.

[0014] One side and the other side of the adsorption portion are respectively in contact with the inner surface of the battery cell receiving portion and the fire extinguishing coolant filled in the battery cell receiving portion, and the other side of the adsorption portion in contact with the fire extinguishing coolant is waterproofed to prevent leakage of the fire extinguishing coolant to the outside of the battery cell receiving portion.

[0015] The above-described battery assembly for preventing thermal runaway may further include a separator disposed on the lower surface of the cover portion to prevent the flow of the extinguishing coolant.

[0016] The above cover portion forms a gas exhaust passage connected to the above separator, and the above separator may be provided with a waterproof and breathable material to guide the gas inside the battery pack generated when a fire occurs in the battery cell to the gas exhaust passage.

[0017] The above-described battery assembly for preventing thermal runaway may further include a gas detection unit disposed in the gas discharge path to detect gas discharged into the gas discharge path.

[0018] The above-described battery assembly for preventing thermal runaway may further include a pressure control valve unit positioned on the upper part of the cover portion and regulating the pressure inside the battery pack based on the pressure generated inside the battery pack.

[0019] Specific details of other embodiments are included in the detailed description and drawings.

[0020] The battery pack assembly for preventing thermal runaway according to the present invention can immerse or impregnate multiple battery cells by filling the battery pack with a fire extinguishing coolant comprising either a liquid non-conductive aqueous material or a gel-like non-conductive aqueous mixture in which a non-conductive aqueous material and a superabsorbent resin are mixed. Therefore, when a fire occurs in a battery cell, the ignition point or ignition area is cooled to block heat transfer to multiple battery cells, thereby preventing the occurrence of thermal runaway and extinguishing the fire.

[0021] FIG. 1 is a first operational configuration diagram of a battery assembly for preventing thermal runaway according to an embodiment of the present invention,

[0022] FIG. 2 is a second operational configuration diagram of a battery assembly for preventing thermal runaway according to an embodiment of the present invention,

[0023] FIG. 3 is a third operational configuration diagram of a battery assembly for preventing thermal runaway according to an embodiment of the present invention,

[0024] FIG. 4 is a fourth operational configuration diagram of a battery assembly for preventing thermal runaway according to an embodiment of the present invention.

[0025] Hereinafter, a battery assembly for preventing thermal runaway according to an embodiment of the present invention will be described in detail with reference to the attached drawings.

[0026] FIG. 1 is a first operational configuration diagram of a battery assembly for preventing thermal runaway according to an embodiment of the present invention, FIG. 2 is a second operational configuration diagram of a battery assembly for preventing thermal runaway according to an embodiment of the present invention, FIG. 3 is a third operational configuration diagram of a battery assembly for preventing thermal runaway according to an embodiment of the present invention, and FIG. 4 is a fourth operational configuration diagram of a battery assembly for preventing thermal runaway according to an embodiment of the present invention.

[0027] As illustrated in FIGS. 1 and 2, a battery assembly (1) for preventing thermal runaway according to an embodiment of the present invention comprises a battery cell (10), a battery pack (30), a extinguishing coolant (70), and a coolant supply unit (230). Additionally, a battery assembly (1) for preventing thermal runaway according to an embodiment of the present invention further comprises an injection plug (50), a resupply unit (90), a water level detection unit (110), an adsorption unit (130), a separator (150), a gas detection unit (170), a pressure control valve unit (190), and a control unit (210).

[0028] Multiple battery cells (10) are used. Depending on the shape, the battery cells (10) may be cylindrical, prismatic, or pouch-type. Multiple battery cells (10) are electrically connected to each other by electrode connections. Multiple battery cells (10) interconnected by electrode connections charge electrical energy provided from an external power source. The electrical energy charged in the battery cells (10) is discharged to supply electrical energy to the driving means of an electric vehicle or an autonomous driving robot.

[0029] The battery pack (30) forms a receiving space for accommodating a plurality of electrically connected battery cells (10) and protects the plurality of battery cells (10) from the outside. When the battery pack (30) is mounted, for example, on an electric vehicle or an autonomous driving robot, it protects the plurality of battery cells (10) from external shocks occurring during driving and prevents foreign substances from the external environment from attaching or adhering to the battery cells (10). In one embodiment of the present invention, the battery pack (30) includes a battery cell receiving portion (31) and a cover portion (33). In addition, in one embodiment of the present invention, the battery pack (30) includes an injection portion (35) and a gas exhaust passage (37).

[0030] The battery cell receiving portion (31) has a box shape that forms an opening for the battery cell (10) to be inserted and removed from the upper side and forms a receiving space for the battery cell (10). The battery cell receiving portion (31) also forms a receiving space for a extinguishing coolant (70) for immersing or impregnating the battery cell (10) in the receiving space.

[0031] The cover portion (33) is provided to selectively cover the opening of the battery cell receiving portion (31) having a box shape. The cover portion (33) opens the opening when supplying the battery cell (10) to the battery cell receiving portion (31), and closes the opening after the battery cell (10) is received in the receiving space.

[0032] The injection section (35) and the gas discharge passage (37) are each formed by penetrating the cover section (33). The injection section (35) communicates with the receiving space and forms an injection passage through which a fire extinguishing coolant (70) is injected into the receiving space.

[0033] The gas exhaust passage (37) is connected to the receiving space, like the injection passage. The gas exhaust passage (37) forms a path through which gas generated during a fire in the battery cell (10) is discharged from inside the battery pack (30) to the outside.

[0034] The injection plug (50) is selectively coupled to and separated from the injection section (35) to selectively open and close the injection section (35). For example, the injection plug (50) opens the injection section (35) so that the fire extinguishing coolant (70) is injected into the battery pack (30) from FIG. 1 to FIG. 2. The injection plug (50) closes the injection section (35) after the fire extinguishing coolant (70) is injected into the battery pack (30).

[0035] The extinguishing coolant (70) comprises either a liquid non-conductive water-based material or a gel-type non-conductive water-based mixture in which a non-conductive water-based material and a superabsorbent resin are mixed, and is filled inside the battery pack (30). The extinguishing coolant (70) is filled inside the battery pack (30) as a liquid non-conductive water-based material or is filled inside the battery pack (30) as a gel-type non-conductive water-based mixture in which a liquid non-conductive water-based material and a superabsorbent resin are mixed.

[0036] The extinguishing coolant (70) utilizes the latent heat of evaporation when a fire occurs in the battery cell (10) to maintain the temperature of the battery cell (10) in the ignition area at 100 degrees Celsius or lower, thereby blocking heat transfer to adjacent battery cells (10). By the action of this extinguishing coolant (70), heat transfer between battery cells (10) is blocked, thereby preventing thermal runaway.

[0037] The resupply unit (90) is provided on the side of the battery pack (30) with a hose or the like. The resupply unit (90) forms a flow path for replenishing the extinguishing coolant (70) into the battery pack (30) from a coolant supply unit (230) that is optionally coupled to the battery pack (30).

[0038] A water level detection unit (110) is placed inside the battery pack (30) to detect the water level of the fire extinguishing coolant (70). The water level detection unit (110) detects the water level of the fire extinguishing coolant (70) that naturally evaporates over time. The detection signal detected by the water level detection unit (110) is provided to the control unit (210). The control unit (210) outputs a control signal to control a warning signal device, such as an alarm, according to the detection signal provided by the water level detection unit (110).

[0039] The adsorption portion (130) is positioned along the inner circumference of the battery cell receiving portion (31) to absorb shock transmitted from the outside to the battery cell (10). One side and the other side of the adsorption portion (130) are in contact with the inner surface of the battery cell receiving portion (31) and the fire extinguishing coolant (70) filled in the battery cell receiving portion (31), respectively. The other side of the adsorption portion (130) that is in contact with the fire extinguishing coolant (70) is waterproofed to prevent leakage of the fire extinguishing coolant (70) to the outside of the battery cell receiving portion (31). This adsorption portion (130) is positioned along the circumference of the battery pack (30) when an impact occurs to the battery pack (30) and serves to prevent the fire extinguishing coolant (70) inside the battery pack (30) from leaking to the outside.

[0040] The separator (150) is placed on the lower surface of the cover portion (33) to prevent the flow of the fire extinguishing coolant (70). The separator (150) is connected to the gas exhaust passage (37). The separator (150) is made of a waterproof and breathable material so that in the event of a fire in the battery cell (10), the gas inside the battery pack (30) passes through and is guided to the gas exhaust passage (37).

[0041] The adsorption part (130) and the separator (150) described above can each prevent leakage and flow of the extinguishing coolant (70) filled inside the battery pack (30) to maintain the cooling state inside the battery cell (10).

[0042] A gas detection unit (170) is positioned in the gas exhaust passage (37) to detect gas discharged into the gas exhaust passage (37). When the gas detection unit (170) detects gas, it can be confirmed as a fire in the battery cell (10). When gas generation is detected, the gas detection unit (170) can directly generate a warning signal, or the control unit (210) outputs a control signal to generate a warning signal from a warning means, etc., based on the detection signal provided by the gas detection unit (170).

[0043] The pressure control valve unit (190) is positioned on the upper part of the cover portion (33) and controls the pressure inside the battery pack (30) based on the pressure generated inside the battery pack (30). The pressure control valve unit (190) according to an embodiment of the present invention includes a pressure sensing portion (91) and a control valve (93). The pressure sensing portion (91) detects the pressure inside the battery pack (30). When a fire occurs in the battery cell (10), the pressure inside the battery pack (30) rises, and the pressure sensing portion (91) detects this. The control valve (93) operates to control the pressure inside the battery pack (30) based on the detection signal detected by the pressure sensing portion (91). For example, if the detection signal detected by the pressure sensing portion (91) is determined to be a rise in pressure, the control valve (93) operates to relieve the pressure inside the battery pack (30) to prevent an explosion caused by the rise in pressure inside the battery pack (30). The detection signal detected from the pressure detection unit (91) and the operation of the control valve (93) accordingly can be achieved through the control operation of the control unit (210).

[0044] The control unit (210) may output a control signal to generate a warning signal or to operate a control valve (93) based on a detection signal provided from at least one of the above-described water level detection unit (110), gas detection unit (170), and pressure detection unit (91). The control unit (210) may substantially be included in a Battery Management System (BMS) that manages the battery cell (10).

[0045] Finally, the coolant supply unit (230) is selectively coupled to and separated from the battery pack (30) and supplies a non-conductive aqueous material into the battery pack (30) based on the liquid level of the fire extinguishing coolant (70) filled inside the battery pack (30). As shown in FIG. 3, the fire extinguishing coolant (70) filled inside the battery pack (30) may naturally evaporate over time, causing the liquid level to decrease. At this time, the coolant supply unit (230) is coupled to the resupply unit (90) of the battery pack (30) as shown in FIG. 4 to replenish the liquid non-conductive aqueous material into the battery pack (30).

[0046] The coolant supply unit (230) is coupled to the battery pack (30) based on the decrease in the water level due to the evaporation of moisture from the extinguishing coolant (70) filled inside the battery pack (30), and supplies a non-conductive aqueous material into the battery pack (30) by capillary action. In one embodiment of the present invention, the coolant supply unit (230) includes a storage unit (231) and a supply unit (233).

[0047] The storage unit (231) stores a liquid non-conductive aqueous material. When it is determined that the liquid level of the filled fire extinguishing coolant (70) inside the battery pack (30) is decreasing, the storage unit (231) is optionally connected to the resupply unit (90) of the battery pack (30) to replenish the liquid non-conductive aqueous material inside the battery pack (30).

[0048] The supply section (233) is provided as an inverted U-shaped pipe to supply a liquid non-conductive aqueous material to be replenished from the storage section (231) into the battery pack (30) by capillary action.

[0049] Accordingly, a fire extinguishing coolant containing either a liquid non-conductive aqueous material or a gel-like non-conductive aqueous mixture of a non-conductive aqueous material and a superabsorbent resin can be filled into the battery pack to immerse or impregnate multiple battery cells. Therefore, in the event of a fire in a battery cell, the ignition point or ignition area can be cooled to block heat transfer to multiple battery cells, thereby preventing the occurrence of thermal runaway and extinguishing the fire.

[0050] Although embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention may be implemented in other specific forms without altering the technical concept or essential features thereof. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and their equivalents should be interpreted as being included within the scope of the present invention.

[0051] [National R&D projects that supported this invention]

[0052] [Unique Project ID] 2420010564, [Project Number] 00509076, [Ministry] Ministry of SMEs and Startups, [Research Management Agency] Korea Technology Information Promotion Agency for SMEs, [Research Project Name] SME Technology Innovation Development Project (Market Responsive Type), [Research Task Title] Safety Battery System for Eco-friendly Mobility Application, [Executing Agency] Neuromeca Co., Ltd., [Research Period] 2024.10.01 ~ 2026.09.30

Claims

1. Multiple battery cells and; A battery pack that forms a receiving space for accommodating a plurality of electrically connected battery cells and protects the plurality of battery cells from the outside; A fire extinguishing coolant filled inside the battery pack, comprising either a liquid non-conductive aqueous material or a gel-type non-conductive aqueous mixture in which the non-conductive aqueous material and a superabsorbent resin are mixed; A battery assembly for preventing thermal runaway, characterized by including a coolant supply unit that is selectively coupled to and separated from the battery pack and supplies a non-conductive aqueous material into the battery pack based on the level of the extinguishing coolant filled inside the battery pack.

2. In Paragraph 1, A battery assembly for preventing thermal runaway, characterized in that the coolant supply unit is coupled to the battery pack and supplies a non-conductive aqueous material into the battery pack via capillary action, based on the decrease in the water level due to the evaporation of moisture from the extinguishing coolant filled inside the battery pack.

3. In Paragraph 1, A battery assembly for preventing thermal runaway, characterized by further including a water level sensor disposed inside the battery pack and detecting the water level of the extinguishing coolant.

4. In Paragraph 2, A battery assembly for preventing thermal runaway, characterized by further including a water level sensor disposed inside the battery pack and detecting the water level of the extinguishing coolant.

5. In Paragraph 1, The battery pack comprises a box-shaped battery cell receiving portion that forms an opening for the battery cell to be inserted and removed from the upper side and a receiving space for receiving the battery cell, and a cover portion that selectively opens and closes the opening. A battery assembly for preventing thermal runaway, characterized in that the above-mentioned cover portion has an injection portion formed therein that communicates with the above-mentioned receiving space and into which the fire extinguishing coolant is injected into the above-mentioned receiving space.

6. In Paragraph 5, The above-mentioned battery assembly for preventing thermal runaway is, A battery assembly for preventing thermal runaway, characterized by further including an adsorption portion disposed along the inner circumference of the battery cell receiving portion to absorb shock transmitted from the outside to the battery cell.

7. In Paragraph 6, One side and the other side of the adsorption portion are respectively in contact with the inner surface of the battery cell receiving portion and the extinguishing coolant filled in the battery cell receiving portion, and A battery assembly for preventing thermal runaway, characterized in that the other side of the adsorption portion in contact with the fire extinguishing coolant is waterproofed to prevent leakage of the fire extinguishing coolant to the outside of the battery cell receiving portion.

8. In Paragraph 5, The above-mentioned battery assembly for preventing thermal runaway is, A battery assembly for preventing thermal runaway, characterized by further including a separator disposed on the lower surface of the cover portion to prevent the flow of the extinguishing coolant.

9. In Paragraph 8, The above cover portion forms a gas discharge passage in communication with the above separation membrane, and A battery assembly for preventing thermal runaway, characterized in that the separator is provided with a waterproof and breathable material to allow gas inside the battery pack generated when a fire occurs in the battery cell to pass through and be guided to the gas discharge path.

10. In Paragraph 9, The above-mentioned battery assembly for preventing thermal runaway is, A battery assembly for preventing thermal runaway, characterized by further including a gas detection unit disposed in the gas exhaust path and detecting gas discharged into the gas exhaust path.

11. In Paragraph 9, The above-mentioned battery assembly for preventing thermal runaway is, A battery assembly for preventing thermal runaway, characterized by further including a pressure control valve unit disposed on the upper part of the above cover portion and regulating the pressure inside the battery pack based on the pressure generated inside the battery pack.

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