Thermal runaway protection structure for power battery pack of new energy automobile

Abstract

The invention discloses a thermal runaway protection structure for a power battery pack of a new energy automobile. A flame discharging opening is formed in the bottom of a battery bin; the battery pack comprises a shell, a battery module and a fire extinguishing medium generation unit, wherein the battery module and the fire extinguishing medium generation unit are arranged in the shell. A pressure relief opening is formed in the shell; the pressure relief opening is opened or closed when the air pressure difference between the shell and the outside changes; the fire extinguishing medium generation unit and the pressure relief opening are arranged at the front end and the rear end of the interior of the shell correspondingly. And a monitoring mechanism for triggering the fire extinguishing medium generation unit after detecting that the internal state of the battery pack is abnormal is arranged in the shell. According to the structure, the battery cell state in the battery pack is monitored in advance, the fire extinguishing medium is triggered in time to fill the battery pack before thermal runaway flame erupts, battery cell thermal runaway spreading is restrained, and through the structural design of the battery pack and the battery bin, the flame after thermal runaway is guided to flow and is discharged from the bottom of the battery bin; and the safety of the peripheral battery pack, the vehicle and the periphery of the vehicle is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery pack management equipment, and specifically relates to a thermal runaway protection structure for a power battery pack of a new energy vehicle. Background Art

[0002] As a clean energy alternative, lithium-ion batteries are safe, have a long cycle life, are non-toxic, and pollution-free. If the target voltage is higher, it needs to be achieved by connecting batteries in series. The safety of lithium batteries has always been a big problem. In industrial design, in order to ensure the safety of the battery pack, the battery management system provides protection against overcharge, over-discharge, overcurrent, and overheating. However, the internal short circuit of the battery is a probabilistic event that cannot be prevented and predicted. Although this is only a small probability event, the occurrence of an internal short circuit may lead to devastating consequences.

[0003] In order to obtain a high voltage platform, when multiple battery cells are connected in parallel, the traditional solution is generally to connect the total positive-total negative-total positive-total negative of the modules in close series, so as to obtain a battery pack with a large capacity and high voltage platform. Currently, the battery cells on the market are generally equipped with a pressure relief valve to release the gas generated in the battery during thermal runaway. Due to the close fit of the total positive and negative between the modules, when a battery cell has thermal runaway, the high temperature and high pressure generated will inevitably be transmitted to its adjacent modules, thereby greatly increasing the possibility of a chain reaction of thermal runaway of the battery cells in the adjacent modules.

[0004] After the battery cells in the battery pack thermally run away, the fire extinguishing medium generating unit is triggered to spray the fire extinguishing medium into the battery pack shell. At this time, the internal air pressure of the battery pack rises rapidly until the shell is damaged and the pressure is released to the outside. However, in actual applications, due to the uncertainty of the pressure release position of the shell, once the pressure release position is close to the position of the fire extinguishing medium generating unit, the sprayed fire extinguishing medium cannot fill the battery pack. The fire extinguishing medium cannot be filled to the position of the battery cells where thermal runaway occurs, resulting in the failure of thermal runaway flame retardancy of the battery cells.

[0005] In addition, when a battery pack experiences thermal runaway, violent flames will erupt from the inside of the battery pack. Without flame guidance and buffering, it is easy for the flame to spread to other surrounding battery packs. If it flows upward, there is a risk of igniting the vehicle body, threatening people inside the vehicle, or it may erupt from the battery compartment opening, threatening the safety of people on the side of the vehicle. Therefore, targeted design improvements are needed. Summary of the invention

[0006] The purpose of the present invention is to provide a thermal runaway protection structure for a new energy vehicle power battery pack for use to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: A thermal runaway protection structure for a power battery pack of a new energy vehicle, including a battery compartment and a battery pack disposed in an installation groove of the battery compartment.

[0008] A flame discharge port is provided at the bottom of the battery compartment.

[0009] The battery pack includes a housing, a battery module, and a fire extinguishing medium generating unit disposed inside the housing.

[0010] A pressure relief port is provided on the housing; the pressure relief port opens or closes when the air pressure difference between the inside and outside of the housing changes.

[0011] The fire extinguishing medium generating unit and the pressure relief port are respectively disposed at the front and rear end positions inside the housing.

[0012] A monitoring mechanism is provided inside the housing to trigger the fire extinguishing medium generating unit after detecting an abnormal internal state of the battery pack.

[0013] Preferably, the housing is composed of a cylindrical member with an integral structure, a front end cover, and a rear end cover that close the front and rear openings.

[0014] Preferably, a battery pack support is provided in the installation groove of the battery compartment.

[0015] After the battery pack is inserted into the installation groove of the battery compartment, it is pressed on the battery pack support, and an L-shaped flame discharge channel is formed between the end of the battery pack away from the compartment opening and the lower space.

[0016] Preferably, the battery module includes a cell support and a plurality of single cells fixedly installed on the cell support.

[0017] The pressure relief ports of several of the single cells are all arranged downward and there is a gap between them and the corresponding battery pack housing.

[0018] Preferably, the connection between the lower edge of the rear end cover and the cylindrical member is set as the pressure relief port.

[0019] Preferably, the rear end cover is made of a high resilience metal material.

[0020] The pressure relief port has two states. One is the pressure relief state in which the pressure relief port opens when the internal air pressure of the housing is too high, and the other is the closed state in which the pressure relief port closes when the internal air pressure of the housing is normal.

[0021] Preferably, the fire extinguishing medium generating unit is disposed on the front end cover of the housing.

[0022] Preferably, the fire extinguishing medium generating unit is an aerosol device.

[0023] Preferably, the monitoring mechanism includes a lead assembly disposed on the surface of the battery module, and one end of the lead assembly introduces the fire extinguishing medium generating unit.

[0024] Preferably, the monitoring mechanism further includes a smoke sensor disposed inside the housing.

[0025] Preferably, the monitoring mechanism further includes:

[0026] A BMS detection unit for monitoring the temperature and voltage change values of the battery cells.

[0027] The technical effects and advantages of the present invention: The thermal runaway protection structure of the new energy vehicle power battery pack,

[0028] 1. By setting the relative positions of the pressure relief port and the fire extinguishing medium generating unit, it is ensured that the ejected aerosol can conduct from one end to the other end inside the housing along the inside of the housing until the internal air is exhausted, and the aerosol completely fills the housing, avoiding the problem that the pressure relief port near the fire extinguishing medium generating unit causes the inability to fill the internal space of the housing.

[0029] In addition, the housing is composed of a cylindrical part with an integral structure, a front end cover and a rear end cover that close the front and rear openings, greatly reducing the probability of damage in the middle, reducing the number of connections on the battery pack housing, facilitating the setting of the pressure relief port, and setting the pressure relief port at the rear cover to guide the flame towards the lower rear when the battery cell explodes and burns, improving safety.

[0030] Moreover, the rear end cover is made of a metal material with high resilience such as aluminum alloy. After the aerosol is ejected and all the air inside the housing is exhausted, when the pressure inside and outside the housing is relatively balanced after pressure relief, the pressure relief port automatically closes. At this time, the pressure inside the housing is still higher than the outside, so that external air will not backflow into the housing, thereby ensuring that the aerosol continuously fills the inside of the housing and avoiding the situation where the aerosol continuously leaks and cannot continuously suppress the thermal runaway of the battery cell.

[0031] 2. By detecting the instantaneous temperature of the battery cell through the lead assembly, detecting the smoke concentration inside the battery pack housing through the smoke sensor, and the BMS detection unit real-time monitoring the changes in data such as temperature rise and voltage, it is possible to detect at an earlier stage whether the battery cells in the battery pack will undergo thermal runaway, thereby preventing the entire battery pack from undergoing thermal runaway and generating an explosion, minimizing the loss of battery cells and the difficulty of extinguishing the thermal runaway, and having higher detection efficiency and flame retardant trigger accuracy.

[0032] 3. Increase the structural design of the battery compartment and the battery pack. First, arrange the pressure relief ports of the single cells downward, and set an interval space between the cells and the inner wall of the housing. When a cell undergoes thermal runaway, the gas flows through the interval space below the battery module to initially buffer and guide the flame, causing it to be discharged from the pressure relief port at the rear end of the battery pack, thereby avoiding the situation where the flame bursts out from various positions and causing multi-position leakage of the battery pack.

[0033] In addition, set flame discharge channels below the cells and the battery pack to buffer and guide the erupting flame, causing it to be discharged from the flame discharge port at the bottom of the bottom compartment, avoiding the threat to the vehicle body and the safety around the vehicle caused by the flame discharging upward or in other directions. At the same time, by guiding the flame discharge, the lateral impact of the flame in the battery pack placement groove can be avoided, thereby preventing the adjacent battery pack group from being damaged, and enhancing the safety protection effect after the thermal runaway of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a top view structural schematic diagram of the present invention;

[0035] Figure 2 is a side view structural schematic diagram of the present invention;

[0036] Figure 3 is a structural schematic diagram of the battery module inside the battery pack;

[0037] Figure 4 is a top view structural schematic diagram of the battery pack;

[0038] Figure 5 is a side view structural schematic diagram of the battery pack.

[0039] In the figures: 1. Housing; 110. Cylindrical part; 120. Front end cover plate; 130. Rear end cover plate;

[0040] 2. Battery module; 210. Cell support; 220. Single cell;

[0041] 3. Fire extinguishing medium generating unit; 4. Pressure relief port; 5. Lead assembly; 6. Smoke sensor; 7. BMS detection unit; 8. Battery compartment; 9. Placement groove; 10. Flame discharge port; 11. Pressure relief port; 12. Battery pack support; 13. L-shaped flame discharge channel; 14. Battery pack. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0043] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0044] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] The present invention provides a thermal runaway protection structure for a power battery pack of a new energy vehicle as Figures 1-5 shown, which includes a battery compartment 8 and a battery pack 14 arranged in the placement groove 9 of the battery compartment 8.

[0046] The battery pack 14 includes a housing 1, a battery module 2 and a fire extinguishing medium generating unit 3 arranged inside the housing 1. The fire extinguishing medium generating unit 3 is an aerosol device. By triggering the fire extinguishing medium generating unit 3 inside the housing 1, aerosol is ejected to fill the inside of the housing 1 and the internal air is exhausted, achieving the effect of suppressing combustion, preventing the thermal runaway of the battery cells from spreading to other battery cells, and reducing losses.

[0047] A pressure relief port 4 is provided on the housing 1; the fire extinguishing medium generating unit 3 and the pressure relief port 4 are respectively arranged at the front and rear end positions inside the housing 1. By setting the relative positions of the pressure relief port 4 and the fire extinguishing medium generating unit 3, it is ensured that when the internal pressure of the housing 1 is too high after the aerosol fills the internal space of the housing 1, the pressure relief port 4 opens to release pressure outward. And because the fire extinguishing medium generating unit 3 and the pressure relief port 4 are respectively arranged at the front and rear end positions inside the housing 1, it is ensured that the ejected aerosol can conduct from one end to the other end inside the housing 1 of the housing 1 until the internal air is exhausted, and the aerosol completely fills the housing 1, avoiding the problem that the pressure relief port 4 near the fire extinguishing medium generating unit 3 causes the inability to fill the internal space of the housing 1, and ensuring the effect of suppressing the thermal runaway of the battery cells.

[0048] The housing 1 is composed of a cylindrical member 110 with an integral structure, a front end cover plate 120 and a rear end cover plate 130 that close the front and rear openings. The cylindrical member 110 is a square cylinder or a circular cylinder. The cylindrical member 110 in the middle being an integral structure can greatly reduce the probability of breakage in the middle, reduce the number of connections on the battery pack housing 1, and facilitate the setting of the pressure relief port 4.

[0049] The pressure relief port 4 is arranged on the rear end cover plate 130. When the battery pack 14 is arranged in the battery compartment 8 at the bottom of the vehicle, setting the pressure relief port 4 on the rear end cover plate 130 can keep it away from the opening of the battery compartment, avoiding the risk that the flame generated once the battery pack has a thermal runaway directly rushes out of the opening and causes great damage to the surrounding of the vehicle battery compartment.

[0050] The connection part between the lower edge of the rear end cover plate 130 and the cylindrical member 110 is set as the pressure relief port 4. There is no need to separately open a pressure relief port 4 on the rear end cover plate 130. The number of connecting bolts that fix the upper part of the rear end cover plate 130 to the cylindrical member 110 is more than the number of connecting bolts that fix the lower part of the rear end cover plate 130 to the cylindrical member 110. Therefore, the connection strength of the lower edge of the rear end cover plate 130 is less than that of the other three sides. When the internal air pressure of the housing 1 is too high, the side with lower connection strength will open to achieve pressure relief. And the pressure relief port 4 is arranged at the lower edge of the rear end cover plate 130, which can guide the flame to impact the bottom of the battery compartment 8, avoiding the flame after thermal runaway directly impacting the bottom of the battery 8 compartment and causing internal circuits and other equipment, further improving safety.

[0051] The rear end cover plate 130 is made of a metal material with high resilience such as aluminum alloy. The pressure relief port 4 has two states. One is the pressure relief state in which the pressure relief port 4 opens when the internal air pressure of the housing 1 is too high. The other is the closed state in which the pressure relief port 4 closes when the internal air pressure of the housing 1 is normal. After ensuring that all the air inside the housing 1 is exhausted after the aerosol is ejected and the pressure is relieved until the internal and external air pressures of the housing 1 tend to be balanced, the pressure relief port 4 automatically closes. At this time, the internal air pressure of the housing 1 is still higher than the outside, and external air will not backflow into the housing 1, thus ensuring that the aerosol is continuously filled inside the housing 1 and avoiding the situation where the aerosol cannot continuously suppress the thermal runaway of the battery cells after continuous loss.

[0052] The fire extinguishing medium generating unit 3 is arranged on the front end cover plate 120 of the housing 1. By arranging the fire extinguishing medium generating unit 3 at the front end cover plate 120, it is ensured that after the fire extinguishing medium generating unit 3 is triggered, the released aerosol can spread along the housing 1 all the way towards the pressure relief port 4 at the rear end cover plate 130, thereby exhausting the air inside the housing 1 and continuously filling the internal space of the battery pack.

[0053] The surface of the battery module 2 is provided with a lead assembly 5, and one end of the lead assembly 5 is introduced into the fire extinguishing medium generating unit 3. The temperature of the battery cells is detected through the arranged lead assembly 5. Once a thermal runaway occurs in the battery cells and the temperature exceeds the ignition point of the lead assembly 5, causing the self-ignition of the lead assembly 5, the combustion will be guided into the fire extinguishing medium generating unit 3 all the way, so as to quickly trigger the fire extinguishing medium generating unit 3 to eject the fire extinguishing medium.

[0054] A smoke sensor 6 is also arranged inside the housing 1. When a thermal runaway occurs in the battery cells, intense smoke will be generated before deflagration. Therefore, detecting the smoke can often detect whether the battery cells are about to fail faster, so as to trigger the fire extinguishing medium generating unit 3 more timely, and minimize the loss and the difficulty of suppressing combustion.

[0055] The battery pack further includes a BMS detection unit 7, which is used to detect the voltage and temperature values of the battery cells in the battery pack during the stage change. The BMS detection unit 7 monitors the temperature rise and voltage changes of each battery cell in the battery pack in real time. When an abnormality is detected, the fire extinguishing medium generating unit 3 is directly triggered by an electrical trigger method to eject the fire extinguishing medium outward, so as to block the thermal runaway of the battery cells at a relatively earlier stage, making it more convenient to repair and recycle the battery pack, and reducing the cost and the difficulty of flame retardance.

[0056] A flame discharge port 10 is opened at the bottom of the battery compartment 8; and a battery pack support 12 is arranged in the placement groove 9 of the battery compartment 8. After the battery pack is inserted into the placement groove 9 of the battery compartment 8, it is pressed on the battery pack support 12, and an L-shaped flame discharge channel 13 is formed between the end of the battery pack away from the compartment opening and the lower space. Ensure that the flame ejected from the rear end of the battery pack is conducted through the L-shaped flame discharge channel 13 formed along the rear and lower parts of the battery pack to buffer the impact force of the flame, and at the same time, during the process of guiding and buffering, it is discharged through the flame discharge port 10 at the bottom of the battery compartment 8.

[0057] The battery module 2 includes a battery cell support 210 and a plurality of single battery cells 220 relatively fixedly installed on the battery cell support 210. The pressure relief ports 114 of the plurality of single battery cells 220 are all arranged downward, and there is a gap between them and the relative battery pack housing 1. Since all the pressure relief ports 114 of the single battery cells 220 are arranged downward, after the thermal runaway of the battery cells, the flame erupts downward and flows along the gap space between the lower end of the single battery cell 220 and the inner wall of the battery pack housing 1, and finally is discharged through the pressure relief port 114 at the rear end of the battery pack, which can buffer and guide the flame ejected by the battery cells, and prevent the flame after thermal runaway from erupting in multiple directions, causing safety hazards.

[0058] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A thermal runaway protection structure for a power battery pack of a new energy vehicle, comprising a battery compartment (8) and a battery pack (14) disposed in the placement groove (9) of the battery compartment (8), characterized in that: A flame discharge port (10) is provided at the bottom of the battery compartment (8); The battery pack (14) includes a housing (1), a battery module (2) and a fire extinguishing medium generating unit (3) disposed inside the housing (1); A pressure relief port (4) is provided on the housing (1); the pressure relief port (4) opens or closes when the air pressure difference between the inside and outside of the housing (1) changes; The fire extinguishing medium generating unit (3) and the pressure relief port (4) are respectively disposed at the front and rear end positions inside the housing (1); A monitoring mechanism is provided inside the housing (1) for triggering the fire extinguishing medium generating unit after detecting an abnormal internal state of the battery pack (14).

2. The thermal runaway protection structure for a power battery pack of a new energy vehicle according to claim 1, characterized in that: The housing (1) is composed of a cylindrical member (110) with an integral structure, a front end cover plate (120) and a rear end cover plate (130) that close the front and rear openings.

3. The thermal runaway protection structure for a power battery pack of a new energy vehicle according to claim 1, characterized in that: A battery pack support (12) is provided in the placement groove (9) of the battery compartment (8); After the battery pack (14) is inserted into the placement groove (9) of the battery compartment (8), it is pressed on the battery pack support (12), and an L-shaped flame discharge channel (13) is formed between the end of the battery pack (14) away from the compartment opening and the lower space.

4. The thermal runaway protection structure for a power battery pack of a new energy vehicle according to claim 1, characterized in that: The battery module (2) includes a cell support (210) and a plurality of single cells (220) relatively fixedly mounted on the cell support (210); The pressure relief ports (11)(4) of several of the single cells (220) are all arranged downward and there is a gap between them and the opposite battery pack housing (1).

5. The thermal runaway protection structure for a power battery pack of a new energy vehicle according to claim 1, characterized in that: The connection between the lower edge of the rear end cover plate (130) and the cylindrical member (110) is set as the pressure relief port (4).

6. The thermal runaway protection structure for a power battery pack of a new energy vehicle according to claim 5, characterized in that: The rear end cover plate (130) is made of a high resilience metal material; The pressure relief port (4) has two states. One is the pressure relief state in which the pressure relief port (4) opens when the internal air pressure of the housing (1) is too high, and the other is the closed state in which the pressure relief port (4) closes when the internal air pressure of the housing (1) is normal.

7. The thermal runaway protection structure for a power battery pack of a new energy vehicle according to claim 6, characterized in that: The fire extinguishing medium generating unit (3) is disposed on the front end cover plate (120) of the housing (1).

8. The thermal runaway protection structure for a power battery pack of a new energy vehicle according to claim 1, characterized in that: The fire extinguishing medium generating unit (3) is an aerosol device.

9. The thermal runaway protection structure for a power battery pack of a new energy vehicle according to claim 1, characterized in that: The monitoring mechanism includes a lead wire assembly (5) disposed on the surface of the battery module (2), and one end of the lead wire assembly (5) is introduced into the fire extinguishing medium generating unit (3).

10. The thermal runaway protection structure for a power battery pack of a new energy vehicle according to claim 8, characterized in that: The monitoring mechanism further includes a smoke sensor (6) disposed inside the housing (1).

11. The thermal runaway protection structure for a power battery pack of a new energy vehicle according to claim 9, characterized in that: The monitoring mechanism further includes: A BMS detection unit (7) for monitoring the temperature and voltage change values of the cells.

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