CN216250872U - Liquid cooling system with thermal runaway delay function and battery pack thereof - Google Patents

Abstract

The utility model discloses a liquid cooling system capable of delaying thermal runaway and a battery pack thereof. The battery pack comprises a box body, a plurality of battery modules and a liquid cooling system, wherein the battery modules are contained in the box body, each battery module comprises at least two batteries with battery safety valves, and the liquid cooling system is arranged between the box body and the corresponding battery module. The liquid cooling system comprises a plurality of heat exchange tubes which are parallel to each other, a fire extinguishing channel and a heat exchange channel are arranged in each heat exchange tube, and fire extinguishing materials are packaged in the fire extinguishing channels; at least part of the fire extinguishing channel is made of meltable material, so that high-temperature substances flushed out after the battery safety valve is exploded can melt the fire extinguishing channel to release the fire extinguishing material. The utility model reduces/prevents the possibility of thermal runaway of the battery by optimizing the liquid cooling system and optimizing the battery pack.

Description

Liquid cooling system with thermal runaway delay function and battery pack thereof

Technical Field

The utility model belongs to the technical field of power batteries, and relates to a liquid cooling system capable of delaying thermal runaway and a battery pack thereof.

Background

In order to obtain higher energy/power, a plurality of batteries are often connected to form a module/battery pack, in the current power battery, if the battery is abused or misused, explosion is likely to occur when gas, a large amount of heat or other substances are likely to be generated inside the battery, and in order to obtain high volume energy, the space between the plurality of batteries is relatively small, so that the abnormal battery is easy to cause peripheral chain reaction and even thermal runaway.

In order to solve the problem, a fire extinguishing tank filled with fire extinguishing agents is often additionally used in the industry, certain pressure is pre-installed in the fire extinguishing tank, the fire extinguishing tank is connected into a battery pack through a pipe, a closing valve is arranged on the pipeline, the closing valve is opened in time when a fire disaster happens, the fire extinguishing agents are injected into a battery box through the pressure in the fire extinguishing tank, the fire extinguishing/cooling purpose is achieved, and the disaster is prevented from further expanding.

Compared with the traditional battery pack without a fire extinguishing device, the battery pack has certain fire extinguishing function, but the technology has the following defects:

(1) a pressure tank with certain pressure is required to be additionally equipped;

(2) the pressure tank needs to be measured and checked for safety at regular intervals;

(3) installing the pressure tank at an additional place;

(4) a plurality of accessory accessories such as valve bodies, conveying pipelines and sealing connecting pieces for entering and exiting the box body are needed;

(5) the triggering mode is not very reliable, the switch valve body is triggered by temperature induction/salt mist induction in the battery pack, and the failure risk is high.

SUMMERY OF THE UTILITY MODEL

The problems to be solved by the utility model are as follows: the utility model reduces/prevents the possibility of thermal runaway of the battery by optimizing the liquid cooling system and optimizing the battery pack.

In order to solve the problems, the utility model adopts the following scheme:

a liquid cooling system capable of delaying thermal runaway comprises a plurality of heat exchange tubes which are parallel to each other, wherein fire extinguishing channels and heat exchange channels are arranged in the heat exchange tubes, and fire extinguishing materials are packaged in the fire extinguishing channels; at least part of the fire extinguishing channel is made of meltable material, so that high-temperature substances rushed out after the battery safety valve is exploded can melt the fire extinguishing channel to release the fire extinguishing material.

Further, according to the liquid cooling system with the function of delaying thermal runaway, the end parts of the two ends of the fire extinguishing channel are sealed to form a containing cavity for packaging the fire extinguishing material; and the fire extinguishing channel is provided with weak areas at both ends of the top surface respectively.

Further, according to the liquid cooling system with the function of delaying thermal runaway, the fire extinguishing channel is provided with the exhaust pipe at the weak area, so that the weak area is located inside the connecting end of the exhaust pipe.

Further, according to the liquid cooling system with the function of delaying thermal runaway, a breathable film is pasted on the top of the exhaust pipe.

Further, the liquid cooling system with the function of delaying thermal runaway also comprises the collecting pipe, and two ends of the plurality of heat exchange tubes are connected through the collecting pipe respectively, so that the heat exchange channels are communicated with each other.

Furthermore, the liquid cooling system with the function of delaying thermal runaway also comprises a buffer clamping plate; the heat exchange tube is arranged on the buffer clamping plate.

Further, according to the liquid cooling system capable of delaying thermal runaway, the buffer clamping plate is provided with a plurality of buckling mechanisms, and the heat exchange tube is fixed on the buffer clamping plate through the buckling mechanisms.

Further, according to the liquid cooling system with the function of delaying thermal runaway of the present invention, the fire extinguishing material comprises one or more of aerosol fire extinguishing agent, hexafluoropropane, heptafluoropropane, perfluorohexane, perfluorohexanone, perfluoropolyether, carbon dioxide, ammonium perfluorooctanoate, ethoxy pentafluorocyclotriphosphazene, hexafluoropropylene trimer, trifluoroethyl phosphate, perfluorononene, hydrofluorocarbon compound, cac 2.6H 2O, Na2SO 4.10H 2O, CaBr 2.6H 2O, CH3 coona.3H 2O, paraffin and various acid esters, aliphatic hydrocarbon, aliphatic acid, alcohol and polyene alcohol; the hydrofluorocarbon compound comprises R134A, R125, R32, R407C, R410A and R152.

A battery pack comprises a box body and a plurality of battery modules accommodated in the box body, wherein each battery module comprises at least two batteries provided with battery safety valves; still include as above have the liquid cooling system who delays thermal runaway, the liquid cooling system sets up the box with between the battery module.

Further, according to the battery pack, the fire extinguishing channel is also provided with a temperature sensing line; one end of the temperature sensing line is connected with the medicament bag arranged in the accommodating cavity of the fire extinguishing channel, and the other end of the temperature sensing line is opposite to the safety valve of the battery.

The utility model has the following technical effects: the utility model reduces/prevents the possibility of thermal runaway of the battery by optimizing the liquid cooling system and optimizing the battery pack.

Drawings

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a first embodiment of the present invention.

Fig. 3 is an enlarged view of a broken-line frame portion of fig. 2.

Fig. 4 is an exploded view of fig. 1.

Fig. 5 is an enlarged view of the structure of fig. 4 in a dotted frame portion.

Fig. 6 is a structural view illustrating a heat exchange pipe capable of accommodating two battery modules in a longitudinal direction according to an embodiment of the present invention.

FIG. 7 is a structural diagram of the second embodiment of the present invention when the buffer card is removed.

Fig. 8 is an exploded view of fig. 7.

In the figure: 1 is a liquid cooling system, 11 is a heat exchange pipe, 111 is a fire extinguishing passage, 112 is a heat exchange passage, 12 is a buffer clamping plate, 121 is a buckling mechanism, 1211 is a first clamping pin, 12111 is a groove, 1212 is a second clamping pin, 13 is a collecting pipe, 131 is a connecting hole I, 132 is a connecting hole II, 133 is a through hole, 2 is a liquid inlet joint, 3 is a liquid outlet joint, 4 is a weak area, and 5 is an exhaust pipe.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

A battery pack comprises a box body, a plurality of battery modules contained in the box body and a liquid cooling system 1. The box body comprises a lower box body and a top cover, and the top cover covers the top of the lower box body, so that the battery module is sealed in the box body; the liquid cooling system 1 is arranged between the lower box body and the battery module. Specifically, the type of the box is not limited, and may be a frame profile type, a flat tray type, and an up-down cassette type. The battery module comprises at least two batteries provided with battery safety valves, the opening pressure of the battery safety valves is set to be 0.02-1.00 MPa, and the battery safety valves are preferably set to be 0.6MPa to be opened. The liquid cooling system 1 is a liquid cooling system with the function of delaying thermal runaway.

As shown in fig. 1, 2 and 3, the liquid cooling system 1 includes a plurality of heat exchange tubes 11, a buffer card 12 and a collecting pipe 13, which are parallel to each other, a fire extinguishing channel 111 and a heat exchange channel 112 are disposed in the heat exchange tubes 11, and a fire extinguishing material is enclosed in the fire extinguishing channel 111; the fire extinguishing passage 111 is at least partially made of a meltable material so that a high-temperature substance rushed out after the battery safety valve is exploded can melt it to release the fire extinguishing material. The heat exchange tube 11 is arranged on the buffer clamping plate 12; the two ends of the plurality of heat exchange tubes 11 are respectively connected through the collecting pipes 13, so that the heat exchange channels 112 are mutually communicated, at least one liquid inlet joint 2 is arranged on one collecting pipe 13, at least one liquid outlet joint 3 is arranged on the other collecting pipe 13, the other collecting pipe is connected with the liquid inlet pipe through the liquid inlet joint 2, and the liquid outlet joint 3 is connected with the liquid outlet pipe, so that a circulation channel is formed, the circulation of heating water or cooling water is convenient, and the heating or cooling is implemented on the battery module in the battery pack. The meltable material refers to a high-temperature substance which is rushed out after the battery safety valve is exploded and can melt the battery safety valve, and the meltable material comprises a low-melting-point alloy and a non-metallic material with flame retardant property. The low-melting-point alloy is an alloy with a melting point temperature not more than 300 ℃, and is preferably an aluminum alloy material; plastics with flame retardant properties such as PC or ABS. The buffer clamping plate 12 can not only prevent the heat of the battery module from being transferred to the box body 1; can also be used for fixedly supporting the heat exchange tube 11; in addition, the buffer clamping plate 12 can also play a role in buffering, so that the liquid cooling system 1 is prevented from being influenced by overvoltage or no effective contact; specifically, the buffer card 12 is made of a non-metal material, typically a plastic with flame retardant properties, such as PC, ABS, etc. It will be understood by those skilled in the art that the fire suppressing passage 111 and the heat exchanging passage 112 in the heat exchanging tube 11 may be provided in one or more, that is, any combination. The heat exchange tube 11 plays a role in temperature reduction and fire extinguishing through the fire extinguishing material in the fire extinguishing channel 111, and prevents the heat diffusion of the battery in the battery pack. The fire extinguishing material is released by being triggered by a close battery module or other heat sources, namely adjacent high temperature is transmitted, and the part of the fire extinguishing channel 111 is melted by heat, so that the effects of inflaming retarding, heat insulation, cooling and fire extinguishing are achieved.

Further, the ends of both ends of the fire extinguishing passage 111 are sealed to form a receiving chamber for enclosing the fire extinguishing material. Specifically, the ends of the two ends of the fire extinguishing channel 111 are welded and sealed by using sheets to form a containing cavity, and the sheets are made of the same material as that of the fire extinguishing channel 111, and are made of low-melting-point alloy or plastic with flame retardant property. The fire extinguishing channel 111 and the sheet are hermetically connected in a welding mode, preferably, brazing is carried out, metal with a melting point lower than that of a base metal is used as brazing filler metal, the brazing filler metal is molten after heating, a weldment is not molten, the base metal is wetted by the liquid brazing filler metal, a joint gap is filled, the brazing filler metal and the base metal are mutually diffused, the weldment is firmly connected together, and welding deformation is small. Before soldering, the solder is used to remove the oxide film on the surface of the soldered material, so as to improve the wettability of the solder. The solder is tin-lead solder with lower melting point. A liquid injection hole is formed in the fire extinguishing passage 111 or the sheet, fire extinguishing materials are injected through the liquid injection hole, and after the fire extinguishing materials in the containing cavity are completely injected, the liquid injection hole is sealed; the liquid injection hole can be sealed by using a sealing nail, a sealing bead and the like; the sealing nail is preferably selected in the embodiment, the sealing nail is driven into the liquid injection hole, the sealing nail and the liquid injection hole are in interference fit, welding sealing is carried out, and then structural adhesive is coated and cured to carry out multiple sealing. Those skilled in the art will understand that the fire extinguishing channel 111 or the sheet material may be provided with an exhaust hole communicated with the accommodating cavity, and the speed of pouring the fire extinguishing material is increased by exhausting through the exhaust hole during pouring; the hole is simultaneously sealed after the infusion is complete.

In addition, as shown in fig. 4 and 5, the two ends of the top surface of the fire extinguishing channel 111 are respectively provided with the weak areas 4, under the condition of thermal runaway of the battery, the fire extinguishing material in the accommodating cavity expands to generate gas after being heated, the air pressure increases, the weak areas 4 are broken by the gas to be opened, and the fire extinguishing material in the fire extinguishing channel 111 is sprayed into the battery pack, so that the effects of temperature reduction and fire extinguishing are achieved.

In order to improve the fire extinguishing and cooling speed and effect, the fire extinguishing duct 111 is connected with the exhaust duct 5 at the weak area 4, so that the weak area 4 is located inside the connection end of the exhaust duct 5. When the emergency situation of the battery pack occurs, the battery is out of control due to heat, and high-temperature substances sprayed out through the battery safety valve melt the fire extinguishing channel 111; the fire extinguishing material can be heated, the fire extinguishing material expands to generate gas after being heated, the air pressure is increased, the weak area 4 is broken and opened by the gas, and the gas/liquid is directionally discharged through the exhaust pipe 5, so that the fire extinguishing and cooling speed and effect are improved.

Further, in order to prevent foreign matter from entering the exhaust pipe 5 and to adjust the internal pressure of the exhaust pipe 5, a gas permeable film is attached to the top of the exhaust pipe 5.

For convenience in installation and maintenance, the buffer clamping plate 12 is provided with a buckling mechanism 121, and the heat exchange tube 11 is fixed on the buffer clamping plate 12 through the buckling mechanism 121; in the embodiment, the heat exchange tubes 11 and the buffer clamping plate 12 are eight; the buffer clamping plate 12 is provided with a buckling mechanism 121, and the eight heat exchange tubes 11 are respectively fixed on the buffer clamping plate 12 through the buckling mechanism 121. The skilled person understands that the number of the buffer clamping plates 12 may also be two or more, and specifically may be determined according to the length of the heat exchange tube 11, when the length of the heat exchange tube 11 is sufficient to place two battery modules arranged above the heat exchange tube 11 in the length direction, the number of the buffer clamping plates 12 is two, and certainly, the buffer clamping plates 12 may also be one large block, preferably two, which can meet the requirement of support and save the production cost; as shown in fig. 6. Of course, the heat exchange tube 11 may also be adhered by glue or fixed on the buffer clamping plate 12 by using a clamp fitting screw, and preferably, the fastening mechanism 121 is very convenient to install, replace and maintain.

Further, as shown in fig. 2 and fig. 3, the fastening mechanism 121 includes a first clamping leg 1211 and a second clamping leg 1212, and a side elevation of the first clamping leg 1211 facing the second clamping leg 1212 is provided with a groove 12111 profiling the side surface of the heat exchange tube 11; the heat exchange tube 11 is clamped between the first clamping pin 1211 and the second clamping pin 1212, one side of the heat exchange tube 11 is clamped with the groove 12111, and the other side of the heat exchange tube is abutted to the side vertical surface of the second clamping pin 1212. Those skilled in the art will appreciate that a plurality of snap mechanisms 121 may be provided on the buffer card 12 for mounting one heat exchanger tube 11 in order to improve the snap-fit.

In addition, it should be noted that the case and the battery module are familiar to those skilled in the art and are not in the scope of the present disclosure, and the description of the case and the battery module is not repeated herein.

Those skilled in the art will appreciate that there are many alternative fire extinguishing materials under the above-described configuration. In particular, the fire extinguishing material is required to have flame retardant, heat insulation and fire extinguishing effects after being released. Such as either a fire suppressant, or a coolant, or a phase change material. Specifically, such fire extinguishing materials include, but are not limited to, aerosol fire extinguishing agents, hexafluoropropane, heptafluoropropane, perfluorohexane, perfluorohexanone, perfluoropolyether, carbon dioxide, ammonium perfluorooctanoate, ethoxypentafluorocyclotriphosphazene, hexafluoropropylene trimer, trifluoroethyl phosphate, perfluorononene, hydrofluorocarbon compounds, cac 2.6h2O, Na2SO 4.10h2O, CaBr 2.6h2O, CH3 coona.3h2O, paraffins and mixtures of one or more of various acid esters, aliphatic hydrocarbons, aliphatic acids, alcohols, and polyenols. Among them, the hydrofluorocarbon compounds include, but are not limited to, R134A, R125, R32, R407C, R410A, R152, and the like. The aerosol fire extinguishing agent can be KNO3, Sr (NO3)2, strontium compound and the like; those skilled in the art will appreciate that fire extinguishing materials also generally need to be materials that are non-toxic and non-polluting to the environment.

In addition, a heat conductive silica gel, a heat conductive silicone grease, a heat conductive rubber pad, or other materials with high heat conductivity may be disposed on the top of the heat exchange tube 11. The bottom of the battery in the battery module is in heat transfer contact with the heat exchange tube 11, so that the heat exchange tube 11 is more sensitive in reaction.

In addition, a temperature sensing line (not shown) may be further provided on the fire extinguishing passage 111. The temperature sensing line is an ignition line, one end of the temperature sensing line is connected with a medicament bag arranged in the fire extinguishing channel 111 in the accommodating cavity, and the other end of the temperature sensing line is opposite to a safety valve of the battery. From this, battery thermal runaway ignites the temperature sensing line through battery safety valve spun high temperature material, ignites the medicament package through the temperature sensing line to the fried chamber that holds that opens, the release holds the fire extinguishing material that the intracavity set up and cools down to put out a fire. Specifically, the present embodiment employs a dual trigger to trigger fire suppression. Those skilled in the art will appreciate that the fire suppression triggering mode of the present embodiment may alternatively be implemented. For example, the accommodating chamber may not be provided with a temperature sensing wire.

Example one

As shown in fig. 1 and 4, a fire extinguishing passage 111 is provided in the middle of the heat exchanging tube 11, heat exchanging passages 112 are provided on both sides of the fire extinguishing passage 111, the length of the fire extinguishing passage 111 is greater than that of the heat exchanging passage 112, so that both ends of the fire extinguishing passage 111 are protruded outward, and a weak area 4 is provided on the top surface of the protruded portion of the fire extinguishing passage 111. A connecting hole I131 is formed in the side wall of one side of the collecting pipe 13, and a connecting hole II 132 is further formed in the top surface of the collecting pipe 13; when two ends of the heat exchange tube 11 are connected with collecting pipes 13, the end part of the heat exchange tube 11 is connected with a connecting hole I131, so that the convex end of the middle fire extinguishing passage 111 passes through the connecting hole I131 and is positioned in the collecting pipe 13; the bottom of the exhaust pipe 5 is connected to the fire extinguishing passage 111 in the header 13 through the connection hole ii 132, and the weak area 4 is located in the connection end of the exhaust pipe 5. In order to prevent the risk of water leakage at the joints when the collecting pipe 13 is used for heating water or cooling water circulation, the joints are sealed by welding; specifically, the weak area 4 is formed by drilling a through hole on the top surface of the fire extinguishing pipe 111 through machining, and welding an aluminum-plastic film at the through hole, wherein the thickness of the aluminum-plastic film is smaller than the wall thickness of the fire extinguishing pipe 111.

Example two

As shown in fig. 7 and 8, unlike the first embodiment, a connecting hole i 131 is formed in a side wall of the header 13, and a through hole 133 is formed in a side wall opposite to the side wall; when the heat exchanging tube 11 is connected at both ends thereof with the headers 13, the end of the heat exchanging tube 11 is connected with the connecting hole I131 so that the outer convex end of the middle fire extinguishing passage 111 passes through the connecting hole I131 in order and is connected with the exhaust pipe 5 through the hole 133 and so that the weak area 4 is located in the connecting end of the exhaust pipe 5. Specifically, the weak area 4 is formed by milling a thin-wall sunk groove on the top surface of the fire extinguishing channel 111 through machining; the depth of the thin-wall sunken groove is smaller than the wall thickness of the fire extinguishing channel 111, in the machining process, a limiting step is arranged on the graver, the engraving depth of the graver is limited by the limiting step, the depth of the thin-wall sunken groove is prevented from being too deep, and the limiting step does not rotate along with the cutter head, so that the non-machining surface on the fire extinguishing channel 11 is prevented from being scratched; certainly, the non-machined surface on the fire extinguishing pipeline 11 can be protected, and damage to the cutter head in the moving process is prevented; for example, the non-processed surface of the fire extinguishing pipe 111 is adhered with a material (teflon) with skid resistance and wear resistance. More specifically, in the first step, the heat exchange tubes 11 are formed into a plurality of channels in an extrusion mode, machining is carried out to enable two ends of the fire extinguishing channel 111 to protrude, the end parts of the two ends of the fire extinguishing channel 111 are sealed through sheets, a liquid injection hole is reserved, the top surfaces of the protruding two ends of the fire extinguishing channel 111 are locally thinned and subjected to weakening treatment to form a weak area 4, then fire extinguishing materials are injected through the liquid injection hole, and the liquid injection hole is sealed; secondly, drilling a collecting pipe 13, and welding a liquid inlet joint 2 and a liquid outlet joint 3 of the collecting pipe 13; and thirdly, welding the heat exchange tube 11 and the collecting pipe 13, then welding the exhaust pipe 5 and the fire extinguishing channel 111, and pasting the breathable film on the exhaust pipe 5.

Claims (9)

1. A liquid cooling system with delay thermal runaway, includes a plurality of heat exchange pipes that are parallel to each other, its characterized in that: a fire extinguishing channel and a heat exchange channel are arranged in the heat exchange tube, and a fire extinguishing material is sealed in the fire extinguishing channel; at least part of the fire extinguishing channel is made of meltable material, so that high-temperature substances rushed out after the battery safety valve is exploded can melt the fire extinguishing channel to release the fire extinguishing material.

2. The liquid cooling system with delay of thermal runaway of claim 1, wherein ends of the extinguishing channel at both ends are sealed to form a containing cavity for encapsulating the extinguishing material; and the fire extinguishing channel is provided with weak areas at both ends of the top surface respectively.

3. The liquid cooling system with a delay of thermal runaway of claim 2, wherein the fire suppression passage is provided with an exhaust pipe at the weakened area such that the weakened area is located inside the exhaust pipe connection end.

4. The liquid cooling system with delay of thermal runaway of claim 3, wherein a gas permeable membrane is applied to the top of the vent pipe.

5. The liquid cooling system with thermal runaway delay of claim 1, further comprising a manifold through which two ends of the plurality of heat exchange tubes are respectively connected so that the heat exchange channels are in communication with each other.

6. The liquid cooling system with a delay for thermal runaway of claim 1, further comprising a buffer card; the heat exchange tube is arranged on the buffer clamping plate.

7. The liquid cooling system with thermal runaway delay of claim 6, wherein the buffer card has a plurality of snap mechanisms disposed thereon, and the heat exchange tubes are secured to the buffer card by the snap mechanisms.

8. A battery pack comprises a box body and a plurality of battery modules accommodated in the box body, wherein each battery module comprises at least two batteries provided with battery safety valves; the liquid cooling system with the function of delaying thermal runaway is characterized by further comprising the liquid cooling system with the function of delaying thermal runaway, wherein the liquid cooling system is arranged between the box body and the battery module.

9. The battery pack according to claim 8, wherein a temperature sensing line is further provided on the fire extinguishing passage; one end of the temperature sensing line is connected with a medicament bag arranged in the fire extinguishing channel, and the other end of the temperature sensing line is opposite to a safety valve of the battery.

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