Battery module thermal runaway protection structure and battery pack with thermal runaway protection

Abstract

The utility model provides a battery module thermal runaway protection structure and a battery pack with thermal runaway protection.The battery module thermal runaway protection structure comprises a box body and a cover body, the box body comprises a first partition groove body and a second partition groove body, the first partition groove body and the second partition groove body are arranged in a cross shape to partition the box body into a plurality of unit areas, and each unit area comprises a plurality of battery bins arranged side by side; the battery bins are used for containing batteries, a third partition groove body is arranged between every two adjacent battery bins, the two side walls, adjacent to the battery bins, of each third partition groove body are each of a thin-wall structure, and the first partition groove body, the second partition groove body and the third partition groove body are used for containing heat absorption materials. One end of each of the first partition groove body, the second partition groove body and the third partition groove body is provided with a pressure relief opening, and the pressure relief openings are used for arranging pressure relief valves, so that the problem of thermal runaway of the battery pack is solved.

Description

Technical Field

[0001] The utility model relates to the field of thermal runaway protection of battery packs, and in particular to a battery module thermal runaway protection structure and a battery pack with thermal runaway protection. Background Art

[0002] With the vigorous development of the electric vehicle industry, the energy density of battery cells and systems continues to increase. The number of electric vehicle fire accidents has increased and attracted widespread attention. Safety has become one of the focus issues in the electric vehicle and power battery industry. Under extreme conditions such as thermal abuse, electrical abuse, and mechanical abuse, lithium-ion batteries will trigger exothermic side reactions inside and then destroy the integrity of the electrochemical system, causing it to enter an uncontrollable rapid heat generation state, namely thermal runaway, which will trigger a series of exothermic side reactions in sequence: (1) When the battery temperature reaches 80-120 °C, the metastable components of the solid electrolyte interface film begin to decompose, the negative electrode lithium embedding loses protection and comes into direct contact with the electrolyte, promoting exothermic reactions. (2) When the temperature reaches about 130-170 °C, the diaphragm begins to melt and collapse, and the positive and negative electrodes of the battery come into direct contact, resulting in a short circuit in the battery and generating a lot of heat. (3) When the temperature exceeds 150 °C, the positive electrode material of the battery reaches the pyrolysis temperature and begins to decompose. The decomposition of the positive electrode material causes its structural integrity to be destroyed. At the same time, the generated oxygen will further promote the exothermic decomposition of the electrolyte.

[0003] Once a battery cell experiences thermal runaway and the heat spreads to adjacent cells, it will cause thermal runaway of the adjacent cells, and then cause thermal runaway of the battery module or battery pack, and even fire or explosion. Therefore, it is urgent to study technologies to prevent the spread of thermal runaway between battery cells within a module or between modules, and to strengthen the safety line of defense of power batteries. Utility Model Content

[0004] The utility model provides a battery module thermal runaway protection structure and a battery pack with thermal runaway protection, which solves the problem of thermal runaway of the battery pack.

[0005] In order to solve the above technical problems, the technical solution adopted by the utility model is: a battery module thermal runaway protection structure and a battery pack with thermal runaway protection, including a box body, the box body including a first partition slot body and a second partition slot body, the first partition slot body and the second partition slot body are arranged in a cross to divide the box body into multiple unit areas, each unit area includes a plurality of battery compartments arranged side by side, the battery compartment is used to place batteries, a third partition slot body is provided between adjacent battery compartments, the two side walls of the third partition slot body adjacent to the battery compartment are thin-walled structures, the first partition slot body, the second partition slot body and the third partition slot body are used to place heat-absorbing materials, and the first partition slot body, the second partition slot body and the third partition slot body are respectively provided with pressure relief ports at one end, and the pressure relief ports are used to set pressure relief valves.

[0006] In the preferred solution, a bottom groove is provided under each unit area, the length direction of the bottom groove is perpendicular to the length direction of the battery compartment, one end of the bottom groove is open and provided with a removable cover, the bottom end of the battery compartment and the bottom groove are adjacent to a thin-walled structure, and the bottom groove is used to place heat-absorbing materials.

[0007] In a preferred solution, a plurality of bottom grooves arranged in parallel and at intervals are provided below the same unit area, and ventilation holes are connected between adjacent bottom grooves.

[0008] In the preferred embodiment, the pressure relief valve includes a cylinder, which is a central through structure, an inner conical surface is provided at one end of the cylinder, a top plug is provided inside the cylinder, an outer conical surface is provided at one end of the top plug, the outer conical surface of the top plug abuts against the inner conical surface of the cylinder, an end cover is provided at the other end of the cylinder, the end cover is provided with a cylindrical structure, the inner wall of the cylindrical structure is slidably connected with the outer wall of the top plug, a countersunk structure is provided at one end of the top plug close to the cylindrical structure, a spring is provided in the countersunk structure, the end of the spring abuts against the bottom end of the cylindrical structure, an air outlet is provided at the bottom end of the cylindrical structure, an air inlet is provided on the side wall of the top plug countersunk structure, and a cavity is provided between the outer wall of the top plug and the inner wall of the cylinder.

[0009] In a preferred embodiment, the outer wall of the cylindrical structure is threadedly connected to the column.

[0010] A battery pack with thermal runaway protection, characterized in that it comprises a box body and a cover body, the box body comprises a first partition trough body and a second partition trough body, the first partition trough body and the second partition trough body are arranged in a cross to divide the box body into a plurality of unit areas, each unit area comprises a plurality of battery compartments arranged side by side, each battery compartment is provided with a plurality of sheet batteries arranged side by side, a third partition trough body is provided between adjacent battery compartments, the two side walls of the third partition trough body adjacent to the battery compartment are thin-walled structures, heat absorbing materials are provided in the first partition trough body, the second partition trough body and the third partition trough body, and pressure relief ports are provided at one end of the first partition trough body, the second partition trough body and the third partition trough body respectively.

[0011] The beneficial effects of the utility model are as follows: the battery containing structure is divided into zones, and the zones are separated by heat absorbing materials, and a layer of heat absorbing materials is arranged at regular intervals in the unit zone, which can quickly respond to changes in system temperature, absorb battery heat, prevent the temperature threshold from being exceeded, and suppress the spread of thermal runaway earlier in the early stages of thermal runaway; the partitioning grooves are distributed throughout the battery compartment, with a large contact area and high heat absorption efficiency; the gas carrying a large amount of heat is discharged through the pressure relief port, rapidly reducing the temperature inside the battery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0013] Figure 1 It is a schematic diagram of the utility model.

[0014] Figure 2It is an internal schematic diagram of the utility model.

[0015] Figure 3 It is a box body structure diagram of the utility model.

[0016] Figure 4 It is an internal diagram of the bottom tank of the utility model.

[0017] Figure 5 It is a sectional view of the box body of the utility model.

[0018] Figure 6 It is a schematic diagram of the closing of the pressure relief valve of the utility model.

[0019] Figure 7 It is a schematic diagram of the pressure relief valve of the utility model being opened.

[0020] Figure 8 This is the distribution diagram of battery cells and heat-absorbing materials inside the first module to the fourth module.

[0021] Fig. 9 This is the maximum temperature distribution diagram of the first battery module.

[0022] Fig.10 This is the maximum temperature distribution diagram of the fourth battery module.

[0023] In the figure: box body 1; mounting ear 101; pressure relief port 102; unit area 2; first partition tank body 3; second partition tank body 4; battery compartment 5; third partition tank body 6; bottom tank 7; vent hole 701; cover body 8; sealing cover 9; pressure relief valve 10; column 1001; top plug 1002; end cover 1003; spring 1004; air inlet 1005; air outlet 1006; cavity 1007; cylindrical structure 1008. DETAILED DESCRIPTION

[0024] Embodiment 1:

[0025] like Figure 1-7 In the invention, a battery module thermal runaway protection structure and a battery pack with thermal runaway protection include a box body 1 and a cover body 8, the box body 1 includes a first partition trough body 3 and a second partition trough body 4, the first partition trough body 3 and the second partition trough body 4 are arranged in a cross to divide the box body 1 into a plurality of unit areas 2, each unit area 2 includes a plurality of battery compartments 5 arranged side by side, the battery compartments 5 are used to place batteries, a third partition trough body 6 is arranged between adjacent battery compartments 5, the two side walls of the third partition trough body 6 adjacent to the battery compartments 5 are thin-walled structures, the first partition trough body 3, the second partition trough body 4 and the third partition trough body 6 are used to place heat absorbing materials, the first partition trough body 3, the second partition trough body 4 and the third partition trough body 6 are respectively provided with pressure relief ports 102 at one end, the pressure relief ports 102 are used to set a pressure relief valve 10.

[0026] Multiple sheet-shaped battery blocks can be placed side by side in each battery compartment 5. The heat-absorbing material can be a solid->liquid, liquid->gas, or solid->gas phase change material, such as hydrogel. The material can also undergo chemical reactions to actively absorb heat and reduce the temperature.

[0027] The side wall of the third partition tank body 6 can be made of a thin-walled metal sheet with good thermal conductivity. When the battery in the battery compartment 5 heats up and reaches a certain temperature, the heat-absorbing material in the third partition tank body 6 changes phase or undergoes a chemical reaction, and absorbs a large amount of heat in the adjacent battery compartment 5 and discharges it from the pressure relief port 102. In addition, when the heat accumulation in each unit area 2 reaches a certain temperature, the heat-absorbing material in the first partition tank body 3 and the second partition tank body 4 changes phase or undergoes a chemical reaction, and exhausts the gas through the pressure relief port 102, thereby having a dual heat absorption and cooling effect.

[0028] Due to the separation of the side walls of the third partitioning groove 6, the heat absorbing material does not directly contact the battery itself and will not corrode the battery.

[0029] In the preferred embodiment, a bottom groove 7 is provided under each unit area 2, the length direction of the bottom groove 7 is perpendicular to the length direction of the battery compartment 5, one end of the bottom groove 7 is open and provided with a removable cover 9, the bottom end of the battery compartment 5 and the bottom groove 7 are adjacent to a thin-walled structure, and the bottom groove 7 is used to place heat-absorbing materials.

[0030] A partition trough with heat-absorbing material is also arranged on the bottom surface of the battery compartment 5. Cooling auxiliary structures are provided on both side ends in the width direction, one side end in the length direction, and the bottom end of each battery compartment 5, so that the heat dissipation area is large and the effect is better.

[0031] In a preferred solution, a plurality of bottom grooves 7 arranged in parallel and at intervals are provided below the same unit area 2 , and ventilation holes 701 are connected between adjacent bottom grooves 7 .

[0032] A plurality of mounting ears 101 are provided near the bottom end of the outer wall of the box body 1, and the mounting ears 101 are used for mounting and fixing with other parts. Since the mounting ears 101 at the length end cannot interfere with the open end position of the bottom groove 7, a design of multiple bottom grooves 7 arranged in a separated manner is adopted, and holes are drilled to connect the bottom grooves 7 adjacent to the same area to avoid the bottom groove 7 near the inner side from being unable to release gas.

[0033] In a preferred embodiment, the pressure relief valve 10 includes a cylinder 1001, which is a central through structure, an inner conical surface is provided at one end of the cylinder 1001, a top plug 1002 is provided inside the cylinder 1001, an outer conical surface is provided at one end of the top plug 1002, the outer conical surface of the top plug 1002 abuts against the inner conical surface of the cylinder 1001, an end cap 1003 is provided at the other end of the cylinder 1001, and the end cap 1003 is provided with a cylindrical structure 1008, and the inner part of the cylindrical structure 1008 is provided with a cylindrical structure 1008. The wall is slidably connected with the outer wall of the top plug 1002. A countersunk structure is provided at one end of the top plug 1002 close to the cylindrical structure 1008. A spring 1004 is provided in the countersunk structure. The end of the spring 1004 abuts against the bottom end of the cylindrical structure 1008. An air outlet 1006 is provided at the bottom end of the cylindrical structure 1008. An air inlet 1005 is provided on the side wall of the countersunk structure of the top plug 1002. A cavity 1007 is provided between the outer wall of the top plug 1002 and the inner wall of the column 1001.

[0034] Each partition tank body can be provided with at least two pressure relief ports 102, which are distributed up and down. The upper pressure relief port 102 is provided with a pressure relief valve 10, with the top plug 1002 end facing inward and the air outlet 1006 facing outward. The hot gas generated by the phase change or chemical reaction of the heat-absorbing material pushes open the top plug 1002, enters the inner cavity of the countersunk structure of the top plug 1002 from the cavity portion 1007 and the air inlet 1005, and is finally discharged from the air outlet 1006 at the bottom of the cylindrical structure 1008.

[0035] A one-way valve can be installed at the pressure relief port 102 below. The structure of the one-way valve can be the same as that of the pressure relief valve 10, but the spring 1004 therein is replaced with a model with lighter elasticity, and the installation direction is opposite to that of the pressure relief valve 10. After cooling, the air pressure in the partition tank body decreases, and external air can enter to balance the air pressure.

[0036] In a preferred embodiment, the outer wall of the cylindrical structure 1008 is threadedly connected to the column 1001.

[0037] The inner wall of the column 1001 and the outer wall of the cylindrical structure 1008 can be connected by pipe threads and coated with thread sealant.

[0038] There are multiple air inlet holes 1005 distributed along the circumferential direction, and multiple air outlet holes 1006 can also be drilled to increase the exhaust flow rate.

[0039] Embodiment 2:

[0040] A battery module is composed of battery cells and heat-absorbing materials. The battery cells and heat-absorbing materials connected in series and parallel are placed in the metal structural parts of the battery module to form a whole, and are wrapped with a blue film on the outside.

[0041] The heat absorbing material comprises, by mass percentage, 80-94% of heat absorbing material, 1-10% of heat conducting material, 0-1% of organic tin catalyst loaded with flame retardant graphite and 5-10% of adhesive.

[0042] The heat-absorbing material undergoes chemical reactions between 60-400°C and actively absorbs heat. This temperature starting area is exactly the starting temperature of thermal runaway, which is close to the starting temperature of decomposition of metastable components of the solid electrolyte interface film. The material has good strength, good vibration resistance, fast heat absorption speed, and high heat absorption enthalpy value (greater than 1200J / g). It can respond immediately when the battery module has abnormal temperature and absorb heat to reduce the temperature.

[0043] The metal structural parts of the battery module are made of stainless steel, aluminum alloy and other materials, and the wall thickness of the cavity where the heat-absorbing material is placed is 0.5-1mm. The heat-absorbing material can prevent thermal runaway from spreading inside the module.

[0044] The heat-absorbing material needs to be processed and formed into a specified size, tightly placed into the metal structure of the battery module, and then the cavity is sealed by selecting a suitable welding method, such as resistance welding, CO2 gas shielded welding, arc welding, to ensure airtightness.

[0045] A pressure exhaust valve is provided on the cavity where the heat absorbing material is placed in the metal structural part of the battery module. After the heat absorbing material actively absorbs heat through chemical reaction, the temperature and pressure inside the cavity where the material is placed will rise. A pressure exhaust valve is provided on the cavity to discharge the gas and heat produced by the chemical reaction from the cavity in time, so that the internal heat absorbing material can continue to play a role in absorbing heat. When the pressure inside the cavity reaches 0.3-0.5Mpa, the pressure exhaust valve can open automatically.

[0046] The size and number of heat absorbing materials placed in the module are determined according to the energy density of the battery cell and the module size requirements. The thickness of the heat absorbing material can be adjusted within the range of 1-30mm.

[0047] In order to achieve the above-mentioned purpose of the invention, the second aspect of the utility model proposes a battery pack, which is composed of a battery module and a heat-absorbing material. The battery module and the heat-absorbing material are placed in a metal structural member of the battery pack to form a whole.

[0048] The heat absorbing material is the same as above.

[0049] The metal structural parts of the battery pack are made of stainless steel, aluminum alloy and other materials, and the wall thickness of the cavity where the heat-absorbing material is placed is 10-30mm. The heat-absorbing material can prevent thermal runaway from spreading between battery modules.

[0050] The heat-absorbing material needs to be processed and formed into a specified size, tightly placed into the metal structural part of the battery pack, and then the cavity is sealed by selecting a suitable welding method, such as resistance welding, CO2 gas shielded welding, and arc welding, to ensure airtightness.

[0051] A pressure exhaust valve is provided on the cavity where the heat absorbing material is placed in the metal structural part of the battery pack. After the heat absorbing material actively absorbs heat through chemical reaction, the temperature and pressure inside the cavity where the material is placed will rise. A pressure exhaust valve is provided on the cavity to discharge the gas and heat produced by the chemical reaction from the cavity in time, so that the internal heat absorbing material can continue to play a role in absorbing heat. When the pressure inside the cavity reaches 0.3-0.5Mpa, the pressure exhaust valve can open automatically.

[0052] The heat-absorbing material fits tightly to the battery module and battery pack, and can quickly respond to system temperature changes based on the special properties of the material itself. Once the temperature exceeds 60-70°C, it can suppress the spread of thermal runaway earlier in the early stages of thermal runaway.

[0053] During the continuous process of thermal runaway, once the internal pressure of the heat-absorbing material cavity exceeds 0.3-0.5MPa, the pressure exhaust valve will automatically open to discharge the heat generated by the chemical reaction in time, so that the internal heat-absorbing material can continue to play its heat-absorbing role and improve the utilization rate of the heat-absorbing material.

[0054] Compared with thermal insulation materials such as aerogel, the advantage of combining the heat-absorbing material described in the utility model with the battery module / battery pack is that the heat absorption enthalpy value is high, and the temperature control areas are divided inside and between the modules, which can cope with the risk of simultaneous thermal runaway of multiple battery cells / battery modules in extreme cases.

[0055] The heat-absorbing material is easy to shape and can be customized according to the actual battery module and battery pack required size. It is integrated with the metal structural parts of the battery module / battery pack to facilitate batch modular installation, making the production cost more advantageous than thermal insulation materials such as aerogel.

[0056] Embodiment 3:

[0057] A thermal runaway protection battery module and battery pack combined with a heat absorbing material, the specific structure is as follows:

[0058] (1) The battery module metal should be made of stainless steel.

[0059] (2) Select a battery cell with a cell capacity of 80Ah and a size of 580*110*20mm.

[0060] (3) The size of the heat-absorbing material is 570*108*20mm, the model is RT110, and after being installed in a stainless steel shell with a pressure exhaust valve and a thickness of 1mm, it is welded into a closed whole by resistance welding.

[0061] (4) Place a piece of heat-absorbing material wrapped in a stainless steel shell next to every four battery cells, such as Figure 3 As shown in the figure, each battery module has 20 battery cells and 4 heat absorbing materials.

[0062] (5) The entire battery pack consists of four modules, and there are four pieces of heat-absorbing materials between the modules as partitions.

[0063] In order to verify the excellent performance of the battery module and battery pack of the utility model, the following verification tests were carried out. The test methods are as follows:

[0064] (1) First battery module: Puncture the middle of the No. 14 battery cell.

[0065] (2) Fourth battery module: Puncture the middle of battery cells No. 10 / 14 / 18.

[0066] like Figure 8-10 The above acupunctures are carried out simultaneously to observe whether the battery pack will catch fire and explode under the condition of thermal runaway, and thermocouples are used to record the temperature of the battery module side in four areas to determine whether the thermal runaway spreads.

[0067] The test results are as follows:

[0068] (1) Temperature change trend of the first battery module: The highest temperature of the needle-punctured battery cell No. 14 reached 1000℃, and the surrounding battery cells were about 620-650℃, all of which had thermal runaway; after the heat absorption of the heat-absorbing material No. 26 / 27, the pressure exhaust valve on the shell was opened, and the temperature of the battery cell on the other side was about 150-190℃; after the heat absorption of the heat-absorbing material No. 25 / 28, the temperature of the battery cell on the other side was about 55-80℃. After 2 hours, the temperature of all battery cells was lower than 130℃, and no thermal runaway spread occurred. This shows that the battery module designed by the utility model can effectively prevent the spread of thermal runaway. After the test, there was still a large amount of heat-absorbing material remaining, indicating that it can continue to play a heat-absorbing role.

[0069] (2) Temperature change trend of the fourth battery module: The highest temperature of the needle-punctured battery cells No. 10 / 14 / 18 reached 1000°C, and the temperature of the surrounding battery cells was about 630-700°C, all of which were in thermal runaway; the heat-absorbing materials No. 25 / 26 / 27 / 28 worked together, and the pressure exhaust valves on the shell were all opened, making the temperature of the battery cells on both sides 200-245°C. After 2.5 hours, the temperature of all battery cells was lower than 130°C, and no thermal runaway spread occurred. This shows that the battery module designed by the utility model can cope with the situation of thermal runaway of multiple battery cells at the same time, such as thermal runaway of multiple battery cells caused by traffic accidents or road failures, and has a very good effect.

[0070] (3) After the first and fourth modules were punctured, the highest temperatures of the second and third modules were between 60 and 70°C, and no thermal runaway occurred. The modules were intact. The heat-absorbing material in the middle partition played the role of "heat absorption + heat insulation". There was still a large amount of it left after the test, indicating that it can continue to play a large role in heat absorption.

[0071] The results are analyzed as follows: The battery module and battery pack are an integrated structural design combined with heat-absorbing materials, which enables the material to respond to temperature changes in a timely manner and adjust the temperature in time at the early stage of thermal runaway, thereby preventing the spread of thermal runaway. In addition, the exhaust valve set on the cavity where the heat-absorbing material is placed can timely discharge the heat generated by the chemical reaction, so that the internal heat-absorbing material can continue to play a heat-absorbing role and improve the utilization rate of the heat-absorbing material. The modular assembly of the heat-absorbing material after molding can realize mass production and reduce production and manufacturing costs.

[0072] Embodiment 4:

[0073] A thermal runaway protection material that absorbs heat quickly. The thermal runaway protection material has good strength, good vibration resistance, thermal conductivity>1W.mK, fast heat absorption speed, chemical reaction occurs between 60 and 400°C and actively absorbs heat. After the chemical reaction conditions are met, the heat absorption reaction will proceed spontaneously, forming a continuous heat absorption effect (the heat absorption enthalpy of the internal high thermal conductivity heat absorption material>1200J / g). A sufficient amount of thermal runaway protection material can reduce the maximum temperature of thermal runaway and prevent fire and explosion caused by high temperature.

[0074] The thermal runaway protection material with rapid heat absorption has a laminated structure, which comprises, from bottom to top, a flame-retardant graphite thermal conductive film, a thermal conductive adhesive, a high thermal conductivity heat-absorbing material, a thermal conductive adhesive and a flame-retardant graphite thermal conductive film; the peripheral sides of the laminated structure are all sealed with edge sealing adhesive.

[0075] The thickness of the thermal conductive adhesive is between 0.02 mm and 0.25 mm; the thickness of the flame retardant graphite thermal conductive film is between 0.02 mm and 0.5 mm; the thickness of the high thermal conductivity and heat absorption material is determined according to actual conditions, preferably between 0.5-100 mm.

[0076] The high thermal conductivity heat-absorbing material comprises, by mass percentage: 80-94% heat-absorbing material, 1-10% heat-conducting material, 0-1% organic tin catalyst loaded with flame-retardant graphite, and 5-10% adhesive. The preparation method is as follows:

[0077] S1: Add adhesive, organic tin catalyst loaded with flame retardant graphite, and thermal conductive material into a mixing kettle, heat to 30-60°C and stir for 2-4 hours;

[0078] S2: slowly add the heat absorbing material into the above mixing kettle, stir while adding, and vacuumize to remove bubbles to obtain a mixed glue;

[0079] S3: Pour the mixed glue into a polytetrafluoroethylene mold of specified shape and thickness or a mold with a polytetrafluoroethylene coating on the surface, and cure it at room temperature for 0.5-48 hours;

[0080] S4: After the curing time is reached, demoulding and grinding the edges to obtain the high thermal conductivity heat absorbing material.

[0081] The heat-absorbing material includes, but is not limited to, a mixture of one or more of sodium acetate trihydrate, ammonium ferric oxalate trihydrate, citric acid monohydrate, citric acid, oxalic acid dihydrate, anhydrous oxalic acid, malonic acid, magnesium sulfate heptahydrate, zinc sulfate heptahydrate, succinic acid, maleic acid, fumaric acid, sodium carbonate decahydrate, calcium chloride hexahydrate, aluminum nitrate nonahydrate, ammonium pentaborate octahydrate, ammonium ferric sulfate dodecahydrate, ferrous chloride tetrahydrate, ammonium oxalate monohydrate, sodium tetraborate decahydrate, sodium tetraborate pentahydrate, aluminum sulfate octahydrate, ammonium pentaborate, ammonium hydrogen borate tetrahydrate, sodium silicate pentahydrate, hydrated sodium aluminosilicate, potassium aluminum sulfate dodecahydrate, sodium sulfate decahydrate, copper sulfate heptahydrate, ferrous sulfate heptahydrate, cobalt chloride hexahydrate, calcium sulfate dihydrate, etc., in any proportion. Preferably, the heat-absorbing material includes but is not limited to a mixture of one or more of oxalic acid dihydrate, anhydrous oxalic acid, ammonium oxalate monohydrate, barium hydroxide octahydrate, sodium acetate trihydrate, boric acid, ammonium pentaborate octahydrate, sodium tetraborate decahydrate, potassium aluminum sulfate dodecahydrate, sodium sulfate decahydrate, calcium sulfate dihydrate, etc. in any proportion, and the mixture preferably has a mesh size between 100 and 500 meshes.

[0082] The heat-conducting material is a mixture of one or more carbon-based heat-conducting materials such as carbon nanotubes, flame-retardant graphite, expanded graphite and graphene in any proportion.

[0083] The organic tin catalyst loaded with flame retardant graphite is prepared as follows: flame retardant graphite and dibutyltin diacetate are added into a reactor at a mass ratio of 1:1 to 2:1, cyclohexane of 30 to 100% of the total mass of flame retardant graphite and dibutyltin diacetate is added, stirring is maintained at 50°C for 2 to 3 hours, and the mixture is placed in a constant temperature drying oven at 80 to 90°C and dried for 24 hours to obtain an organic tin catalyst loaded with flame retardant graphite. Among them, the flame retardant graphite is preferably flake graphite. The flame retardant graphite itself also has a very good thermal conductivity, and the addition of an organic tin catalyst loaded with flame retardant graphite can also improve the thermal conductivity of the material.

[0084] The adhesive is a low-viscosity adhesive with a viscosity range of 5 to 200 mPa.s (25°C), preferably an LPA-type low-viscosity infusion adhesive. The adhesive has low viscosity, low density, and strong penetration ability. It contains a special wetting dispersant and has excellent wettability on the surface of the heat-absorbing material. The adhesive only needs 5 to 10% of the total mass to achieve high solid content filling of the heat-absorbing material, and the operation time is long. The curing time can be adjusted according to the addition amount of the flame-retardant graphite-loaded organic tin catalyst to meet different application requirements.

[0085] The heat absorption principle of the high thermal conductivity heat absorbing material is that the heat absorbing material undergoes a chemical reaction at high temperature, for example, the heat absorbing material decomposes to generate water, carbon dioxide and other substances, and actively absorbs a large amount of heat during this chemical reaction. The generated carbon dioxide can isolate the combustibles from contact with the air, and has the effect of preventing fire.

[0086] The thermally conductive adhesive is preferably SE4450 double-component thermally conductive adhesive produced by Dow Chemical, with a thermal conductivity coefficient of >1 W / mK and a thickness of between 0.02 mm and 0.2 mm.

[0087] The thickness of the flame retardant graphite thermal conductive film is between 0.02mm and 0.5mm. It is a thermal conductive film prepared using flame retardant graphite composite plastic particles. The thermal conductivity of the plastic particles is greater than 1W / mK, and the flame retardancy level reaches UL94-V0 level. Suitable plastics include but are not limited to one or more of polyamide, polyvinyl chloride, polycarbonate, polyphenylene sulfide, polyetheretherketone, polybutylene succinate, polyethylene terephthalate, polypropylene, etc.

[0088] The preparation method of the thermal runaway protection material for rapid heat absorption is as follows: a layer of thermal conductive glue is brushed on the upper and lower surfaces of the high thermal conductivity heat-absorbing material, and then the surface of the thermal conductive glue is covered with a flame-retardant graphite thermal conductive film, and both are flattened using a mold, placed at room temperature for 0.5 to 48 hours, cut into a specified size, and then brushed with edge sealing glue on the side, and placed at room temperature for 1 to 48 hours to obtain the high thermal conductivity heat-absorbing material. The preparation method of the thermal runaway protection material for rapid heat absorption is actually also a method for achieving high thermal conductivity and modular packaging of heat-absorbing materials. First, the powder heat-absorbing material and the heat-conducting material, and the organic tin catalyst loaded with flame-retardant graphite are compounded and preliminarily packaged by adhesive, and then the heat-conducting glue and the flame-retardant graphite thermal conductive film are combined for further stacking and packaging and edge sealing, so that the high thermal conductivity and packaging effect of the heat-absorbing material described in the present invention can be achieved, and a fast heat-absorbing thermal runaway protection block or sheet is made, and the size can be controlled according to demand to achieve modular installation.

[0089] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A battery module thermal runaway protection structure and a battery pack with thermal runaway protection, characterized in that: The box body (1) comprises a first partitioning groove body (3) and a second partitioning groove body (4), the first partitioning groove body (3) and the second partitioning groove body (4) are arranged in a cross shape to divide the box body (1) into a plurality of unit areas (2), each unit area (2) comprises a plurality of battery compartments (5) arranged side by side, the battery compartments (5) are used to place batteries, a third partitioning groove body (6) is arranged between adjacent battery compartments (5), the two side walls of the third partitioning groove body (6) adjacent to the battery compartments (5) are thin-walled structures, the first partitioning groove body (3), the second partitioning groove body (4) and the third partitioning groove body (6) are used to place heat absorbing materials, one end of the first partitioning groove body (3), the second partitioning groove body (4) and the third partitioning groove body (6) are respectively provided with a pressure relief port (102), the pressure relief port (102) is used to set a pressure relief valve (10).

2. The battery module thermal runaway protection structure and the battery pack with thermal runaway protection according to claim 1 are characterized in that: A bottom groove (7) is provided below each unit area (2), the length direction of the bottom groove (7) being perpendicular to the length direction of the battery compartment (5), one end of the bottom groove (7) being open and provided with a detachable cover (9), the bottom end of the battery compartment (5) adjacent to the bottom groove (7) being a thin-walled structure, and the bottom groove (7) is used to place a heat-absorbing material.

3. The battery module thermal runaway protection structure and the battery pack with thermal runaway protection according to claim 1 are characterized in that: A plurality of bottom grooves (7) arranged in parallel and spaced apart are provided below the same unit area (2), and ventilation holes (701) are connected between adjacent bottom grooves (7).

4. The battery module thermal runaway protection structure and the battery pack with thermal runaway protection according to claim 1 are characterized in that: The pressure relief valve (10) comprises a cylinder (1001), the cylinder (1001) is a central through structure, one end of the cylinder (1001) is provided with an inner conical surface, a top plug (1002) is provided in the cylinder (1001), one end of the top plug (1002) is provided with an outer conical surface, the outer conical surface of the top plug (1002) abuts against the inner conical surface of the cylinder (1001), the other end of the cylinder (1001) is provided with an end cover (1003), the end cover (1003) is provided with a cylindrical structure (1008), the inner wall of the cylindrical structure (1008) and the top plug are connected to each other. The outer wall of the plug (1002) is slidably sleeved, and a countersunk hole structure is provided at one end of the top plug (1002) close to the cylindrical structure (1008), a spring (1004) is provided in the countersunk hole structure, the end of the spring (1004) is against the bottom end of the cylindrical structure (1008), an air outlet (1006) is provided at the bottom end of the cylindrical structure (1008), an air inlet (1005) is provided on the side wall of the countersunk hole structure of the top plug (1002), and a cavity (1007) is provided between the outer wall of the top plug (1002) and the inner wall of the column (1001).

5. The battery module thermal runaway protection structure and the battery pack with thermal runaway protection according to claim 4 are characterized in that: The outer wall of the cylindrical structure (1008) is threadedly connected to the column (1001).

6. A battery pack with thermal runaway protection, characterized by: The invention comprises a box body (1) and a cover body (8), wherein the box body (1) comprises a first partitioning groove body (3) and a second partitioning groove body (4), wherein the first partitioning groove body (3) and the second partitioning groove body (4) are arranged in a cross shape to divide the box body (1) into a plurality of unit areas (2), wherein each unit area (2) comprises a plurality of battery compartments (5) arranged side by side, wherein each battery compartment (5) is provided with a plurality of sheet-shaped batteries arranged side by side, wherein a third partitioning groove body (6) is provided between adjacent battery compartments (5), wherein the two side walls of the third partitioning groove body (6) adjacent to the battery compartment (5) are thin-walled structures, wherein heat absorbing materials are provided in the first partitioning groove body (3), the second partitioning groove body (4) and the third partitioning groove body (6), and pressure relief ports (102) are provided at one end of each of the first partitioning groove body (3), the second partitioning groove body (4) and the third partitioning groove body (6).

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