Fire prevention device for battery pack of electric vehicle

Abstract

The present invention relates to a fire prevention device for a battery pack of an electric vehicle, which can prevent a fire in a battery cell by lowering the temperature of the battery cell by detecting overheating of the battery cell and spraying cooling water.

Description

Fire prevention device for electric vehicle battery packs

[0001] The present invention relates to a fire prevention device for an electric vehicle battery pack, and more specifically, to a fire prevention device for an electric vehicle battery pack that can prevent fire by lowering the temperature of a battery cell by spraying coolant when overheating of the battery cell is detected.

[0002] (Korean text) This work is the result of a local government-university cooperation-based regional innovation project (2022RIS-006), supported by the National Research Foundation of Korea and funded by the Ministry of Education in 2024.

[0003] (English Acknowledgments) This research was supported by “Regional Innovation Strategy(RIS)”through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(MOE)(2022RIS-006).

[0004]

[0005] An electric vehicle's battery pack consists of multiple battery cells grouped together to form a module, and multiple modules together to form a battery pack. Battery cells contain positive and negative electrodes, electrolyte, and other components, and can be repeatedly charged and discharged through electrochemical reactions.

[0006] Battery cells can generate heat during charging and discharging. Furthermore, battery cells can experience thermal runaway if subjected to continuous stress, such as overcharging and overdischarging, exposure to high temperatures, or external impact.

[0007] Electric vehicle battery packs contain multiple battery cells packed tightly into a small space, posing a risk of fire if the heat generated accumulates internally. Therefore, battery packs are being equipped with various structures and methods to dissipate heat to the outside.

[0008] Battery cell fires occur when the electrolyte decomposes due to thermal runaway, generating flammable gases. These gases ignite, spreading heat to adjacent battery cells, and ultimately causing a fire. Battery cell fires are difficult to extinguish with foam or fire extinguishers, and cooling methods, which lower the temperature of the battery cells, are known to be the only effective method.

[0009] Once the heat dissipation in a battery cell reaches a certain level, the fire can spread and become difficult to extinguish. Therefore, it is important to cool the battery cell in advance or quickly extinguish the initial fire.

[0010] Battery cell cooling can be achieved through air-cooling or water-cooling. Air-cooling is primarily used for automotive battery cells due to issues such as leakage and waterproofing. Air-cooling uses aluminum cooling fins to absorb heat from the battery cell and transfer it to a heat sink for cooling.

[0011] Despite the adoption of various cooling methods, it remains difficult to completely prevent battery cell fires. Accordingly, active technology development is underway to extinguish thermal runaway battery cells early and prevent fires from spreading throughout the entire battery pack or vehicle.

[0012] For example, Korean Patent Publication No. 10-2203248 discloses a battery cell stack (battery module) in which fire extinguishing materials are placed at the edges of battery cells to respond to fire.

[0013] However, the above technology has the problem of increasing the size of the battery and increasing the manufacturing cost as separate fire extinguishing equipment is installed inside the electric vehicle or battery.

[0014] [Prior Art Literature]

[0015] Republic of Korea Patent No. 10-2203248 (Publication date: October 17, 2018)

[0016] The present invention has been devised to solve the above-described problems, and provides a fire prevention device for an electric vehicle battery pack that can prevent thermal runaway of battery cells by improving the fire prevention device of the battery pack.

[0017]

[0018] In order to achieve the above-described purpose, the present invention provides a fire prevention device for an electric vehicle battery pack, which is provided at the lower part of a vehicle body, comprising: a battery module comprising a plurality of battery cells; an upper cover for covering the upper part of the battery module to surround and protect the battery module from the outside and to compartmentalize the battery cells, and a lower tray for supporting the lower part of the battery module, wherein the lower tray includes a housing having a first melting portion in which a portion of an area thereof is melted by heat or flame; a cooling panel disposed on a lower surface of the housing, the cooling panel having an inlet port for introducing coolant and an outlet port for introducing coolant, the coolant introduced from the inlet port flowing along a cooling pipe to exchange heat with the battery module; a protective cover disposed on a lower surface of the cooling panel to protect the cooling panel; and an injection unit located on an upper portion of the cooling panel for injecting the coolant flowing in the cooling pipe to the outside.

[0019] In addition, the injection unit may be formed with a plurality of nozzles that are connected to the cooling pipe of the cooling panel and spray coolant in one direction, and a sealing member that is coupled to one side of the nozzle and blocks the injection port of the nozzle.

[0020] In addition, the nozzle may be configured to have an elastic portion formed with a pointed end and capable of being elasticated along the axial direction of the nozzle.

[0021] In addition, the sealing member is formed of a material that melts by heat or flame, and in normal times, the nozzle is pressurized to contract the elastic portion, and when overheating is detected and reaches a certain temperature or higher, the sealing member is melted and removed, so that the force pressing the nozzle is released and at the same time, the elastic portion can be configured to expand by the injection pressure of the cooling water.

[0022] Additionally, the cooling panel may have through holes formed at regular intervals at locations that do not come into contact with the cooling tube.

[0023] Additionally, the protective cover may further include a second melting portion made of a material that melts a portion of the surface by heat or flame.

[0024]

[0025] The fire prevention device of the electric vehicle battery pack according to the present invention having the above configuration can prevent thermal runaway of the battery cell in advance by spraying coolant flowing through the cooling panel when overheating of the battery cell is detected.

[0026] Additionally, when the heat generated from the battery cells reaches a certain temperature, ventilation is provided between the surface of the battery cells and the exterior, allowing the heat generated from the battery cells to be released outside the housing. Furthermore, fire extinguishing fluid provided from an external device can easily penetrate the interior of the battery module, allowing for early extinguishment of the fire.

[0027] In addition, since the effects of the present invention described in this manner are naturally exerted by the composition of the described contents regardless of whether the inventor is aware of them, the above-described effects are only a few effects according to the described contents and should not be recognized as describing all effects that the inventor has identified or actually exists.

[0028] In addition, the effects of the present invention should be additionally understood by the entire description of the specification, and even if not explicitly described in sentences, if a person with ordinary knowledge in the technical field to which the described content belongs can recognize such effects through this specification, then it should be regarded as an effect described in this specification.

[0029]

[0030] Figure 1 is an exploded perspective view of a fire prevention device of a battery pack according to the present invention.

[0031] Figure 2 is a perspective view of a lower tray according to the present invention;

[0032] Figure 3 is a perspective view of a cooling panel according to the present invention;

[0033] Figure 4 is a perspective view of a protective cover according to the present invention;

[0034] Figure 5 is a cross-sectional view of a spray unit according to the present invention;

[0035] Figure 6 is a drawing illustrating the operating state of the injection unit according to the present invention.

[0036]

[0037] ※Explanation of symbols※

[0038] 1: Battery pack 10: Battery module

[0039] 11: Battery cell 20: Housing

[0040] 21: Top cover 22: Lower tray

[0041] 23: First melting section 30: Cooling panel

[0042] 31: Entry port 32: Exit port

[0043] 33: Cooling tube 34: Through hole

[0044] 35: Coolant pump 36: Coolant tank

[0045] 40: Protective cover 41: Second melting section

[0046] 50: Injection unit 51: Nozzle

[0047] 52: Elastic part 53: Sealing member

[0048] 53a: Cutting guide section

[0049]

[0050] The configuration and operation of a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0051] This is intended to explain in detail to a degree that a person having ordinary knowledge in the technical field to which the present invention pertains can easily practice the contents of the present invention, and does not mean that the technical idea and scope of the present invention are limited thereby.

[0052] In addition, when adding reference signs to components of each drawing, it should be noted that identical components are indicated with the same signs as much as possible even if they are shown in different drawings, and terms specifically defined in consideration of the configuration and operation of the present invention may vary depending on the intention or custom of the user or operator, and the definitions of these terms should be determined based on the contents throughout this specification.

[0053] Additionally, throughout the specification, when a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0054] Fig. 1 is an exploded perspective view of a battery pack fire prevention device according to the present invention, Fig. 2 is a perspective view of a lower tray according to the present invention, Fig. 3 is a perspective view of a cooling panel according to the present invention, Fig. 4 is a perspective view of a protective cover according to the present invention, Fig. 5 is a cross-sectional view illustrating a spray unit according to the present invention, and Fig. 6 is a drawing illustrating an operating state of a spray unit according to the present invention. First, description will be made with reference to Fig. 1, and Figs. 2 to 6 will be cited where necessary.

[0055] The present invention is to prevent fire by lowering the temperature of a battery pack (1) installed in the lower part of a body of an electric vehicle (not shown).

[0056] This battery pack (1) may be composed of a battery module (10), a housing (20), a cooling panel (30), a protective cover (40), and a spray unit (50).

[0057] First, the battery module (10) is formed by assembling multiple battery cells (11) into a single assembly. Since the battery cells (11) have a small capacity for individual use, the battery module (10) can be used to increase the capacity and improve performance.

[0058] A battery cell (11) is the basic unit of a battery and can generate electricity through a chemical reaction. Furthermore, the battery cell (11) comprises two electrodes and an electrolyte, enabling repeated charging and discharging through electrochemical reactions. A battery module (10) composed of multiple battery cells (11) can be fixed to a housing (20) described below.

[0059] The housing (20) can surround and protect the battery module (10) described above from the outside and store the battery cells (11) in compartments. This housing (20) can be composed of an upper cover (21) and a lower tray (22). The upper cover (21) can cover the upper part of the battery module (10), and the lower tray (22) can support the lower part of the battery module (10). The housing (20) is generally made of metal and / or synthetic resin, and can stably fix the battery module (10) and provide electrical connection. In addition, the housing (20) can dissipate heat generated from the battery cells (11) to control the temperature of the battery cells (11).

[0060] Referring to Fig. 2, a portion of the lower tray (22) may further include a first melting portion (23) made of a material that melts by heat or flame. The first melting portion (23) should have excellent mechanical strength to protect the battery cell (11) from external impact, and a material that melts when it reaches a certain temperature may be preferable. For example, materials such as polycarbonate (PC), acrylonitrile butadiene styrene (ABS), and nylon, which have excellent mechanical strength and a relatively low melting point, may be used. Accordingly, when the heat generated from the battery cell (11) reaches a certain temperature or higher, ventilation is enabled between the surface of the battery cell (11) and the outside, thereby dissipating the heat generated from the battery cell (11) to the outside of the housing (20). In addition, in case of a fire, the fire extinguishing agent provided from a fire extinguishing device (not shown) separately installed at the bottom of the vehicle body by a firefighter can easily penetrate into the battery module (10), thereby extinguishing the fire early.

[0061] Referring to FIG. 3, the cooling panel (30) is placed on the bottom surface of the housing (20) described above, and effectively absorbs heat generated inside the housing (20) to maintain the temperature of the battery cell (11) constant.

[0062] Specifically, an inlet port (31) through which coolant flows in and an outlet port (32) through which coolant flows out may be formed on one side of the cooling panel (30). Coolant flowing in through the inlet port (31) flows along a cooling pipe (33) and may exchange heat with the battery module (10). This coolant may be circulated through a coolant pump (35) connected to the inlet port (31) and the outlet port (32). In addition, a coolant tank (36) may be further included at a location adjacent to the coolant pump (35). The coolant tank (36) is for replenishing coolant sprayed through a nozzle (51) in the event of a fire.

[0063] In addition, the cooling pipes (33) may be arranged in a double-track U-shaped zigzag pattern within the internal space of the cooling panel (30). In this way, the cooling water flows evenly across the entire area of ​​the cooling panel (30), and the heat generated within the housing (20) can be more efficiently absorbed.

[0064] Meanwhile, the cooling panel (30) may have through holes (34) formed at regular intervals at locations that do not come into contact with the cooling pipe (33). The through holes (34) may be formed in various shapes, such as circular, oval, or polygonal, and are preferably evenly arranged in the length and width directions of the cooling panel (30). This is to enable ventilation between the surface of the battery cell (11) and the outside, as mentioned above.

[0065] Referring to FIG. 4, a protective cover (40) is placed on the lower surface of the cooling panel (30) described above to alleviate shock and vibration generated from the cooling panel (30) as well as the lower part of the vehicle body, and prevent dust and foreign substances from penetrating, thereby extending the life of the battery pack (1) and ensuring safety. The protective cover (40) is generally made of aluminum alloy or synthetic resin plastic, and can be designed to fit the shape of the lower part of the vehicle body.

[0066] The interior of the protective cover (40) is filled with a shock-absorbing cushioning material (not shown), effectively mitigating shock and vibration applied to the battery pack (1). In addition, the exterior of the protective cover (40) can be treated with waterproofing and dustproofing to prevent dust and foreign substances from penetrating.

[0067] Meanwhile, a portion of the protective cover (40) may further include a second melting portion (41) made of a material that melts by heat or flame. Since the characteristics of this second melting portion (41) are similar or identical to those of the first melting portion (23) described above, a detailed description thereof will be omitted. As mentioned above, this is to allow ventilation between the surface of the battery cell (11) and the exterior.

[0068] Referring to FIGS. 5 and 6, the injection unit (50) is positioned on the upper portion of the cooling panel (30) described above and serves to spray the cooling water flowing along the cooling pipe (33) to the outside. This injection unit (50) may be composed of a nozzle (51) and a sealing member (53).

[0069] The nozzle (51) is connected to the cooling pipe (33) and can spray coolant in one direction through the injection port. The nozzle (51) is formed with a pointed end as it goes in the direction of spraying the coolant, and may further include an elastic portion (52) that can be expanded along the axial direction of the nozzle (51).

[0070] Meanwhile, the sealing member (53) can be coupled to one side of the nozzle (51) to block the injection port. Specifically, the sealing member (53) is formed of a material that melts by heat or flame, so as to block and seal the injection port in normal times, and in case of fire, the sealing member (53) is melted and removed, thereby helping the coolant to be sprayed. At this time, a cutting guide portion (53a) can be formed on one side of the sealing member (53). The cutting guide portion (53a) is the portion of the sealing member (53) that melts first, and can be formed relatively thinly. Therefore, if the cutting guide portion (53a) melts first, the portion that was blocking the injection port of the nozzle (51) falls off, so that the coolant can be sprayed more quickly.

[0071] In addition, the sealing member (53) can contract the expansion portion (52) by pressurizing the nozzle (51) in normal times, and when the sealing member (53) is removed, the force pressing the end of the nozzle (51) is released, and at the same time, the nozzle (51) can be extended by the spray pressure of the coolant. In this case, since the end of the extended nozzle (51) is formed to be sharp, the coolant can be directly sprayed onto the battery cell (11) by quickly passing through the residue that may be generated when the first molten portion (23) of the lower tray (22) melts away.

[0072] The battery pack fire prevention device of the present invention for an electric vehicle having the above configuration can prevent thermal runaway of the battery cell (11) in advance by spraying cooling water flowing on the cooling panel (30) when overheating of the battery cell (11) is detected.

[0073] In addition, when the heat generated from the battery cell (11) reaches a certain temperature or higher, the heat generated from the battery cell (11) can be released to the outside of the housing (20) by allowing ventilation between the surface of the battery cell (11) and the outside. In addition, the fire extinguishing agent provided from a separately provided fire extinguishing device can easily penetrate into the inside of the battery module, thereby extinguishing the fire early.

[0074] Although the present invention has been described and illustrated with specific embodiments above, the present invention is not limited to the above-described embodiments, and various changes and modifications are possible within a scope that does not depart from the technical spirit of the present invention.

Claims

1. In a battery pack fire prevention device installed on the lower part of the vehicle body, A battery module consisting of multiple battery cells; A housing comprising an upper cover covering the upper portion of the battery module to protect the battery module from the outside and to compartmentalize the battery cells, and a lower tray supporting the lower portion of the battery module, wherein the lower tray includes a first melting portion in which a portion of the area is melted by heat or flame; A cooling panel disposed on the bottom surface of the housing, having an inlet port through which coolant flows in and an outlet port through which coolant flows out, and the coolant flowing in from the inlet port flows along a cooling pipe to exchange heat with the battery module; A protective cover placed on the bottom of the cooling panel to protect the cooling panel; and A fire prevention device for a battery pack, characterized in that it includes a spray unit located on the upper part of the cooling panel and spraying coolant flowing in the cooling tube to the outside.

2. In paragraph 1, The above injection unit is formed with a plurality of nozzles that are connected to the cooling pipe of the cooling panel and spray the cooling water in one direction, A fire prevention device for a battery pack, characterized in that it comprises a sealing member that is coupled to one side of the nozzle and blocks the nozzle's injection port.

3. In paragraph 2, A fire prevention device for a battery pack, characterized in that the nozzle is formed with a pointed end and has an elastic portion that can be stretched along the axial direction of the nozzle.

4. In paragraph 2 or 3, The above sealing member is formed of a material that melts by heat or flame, and in normal times, the nozzle is pressed to contract the elastic portion. A fire prevention device for a battery pack characterized in that when overheating is detected and a temperature exceeding a certain level is reached, the sealing member is melted and removed, thereby releasing the force pressurizing the nozzle and simultaneously causing the elastic member to expand due to the injection pressure of the coolant.

5. In paragraph 1, A fire prevention device for a battery pack, characterized in that the cooling panel has through holes formed at regular intervals in a location that does not come into contact with the cooling pipe.

6. In paragraph 1, A fire prevention device for a battery pack, characterized in that the protective cover further includes a second melting portion made of a material that melts a portion of an area by heat or flame.

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