Battery thermal runaway propagation prevention system and safe battery

Abstract

Provided in the present invention are a battery thermal runaway propagation prevention system and a safe battery. The battery thermal runaway propagation prevention system comprises a sealed pressure-bearing housing, wherein a heat-absorbing material is provided in the housing, and the heat-absorbing material comprises materials that are rich in water and water of crystallization or generate water. The sealed pressure-bearing housing withstands a pressure of 0.1 MPa to 10 MPa. The housing is further provided with a pressure-maintaining mechanism, which makes the housing open to release pressure when the pressure in the housing exceeds a preset positive pressure, or makes the housing close to maintain pressure when the pressure in the housing is lower than the preset positive pressure after the housing has been opened to release pressure. By using a combined structure of the pressure-bearing housing and the heat-absorbing material, the thermal runaway propagation of battery cells can be well prevented, thereby reducing the risks of fire and explosions in the battery.

Description

Battery heat non-propagation protection system and safe battery TECHNICAL FIELD

[0001] The present application relates to the field of thermal runaway protection, in particular to a battery heat non-propagation protection system and safe battery. BACKGROUND

[0002] The new energy vehicle fire phenomenon caused by heat propagation is a technical problem of thermal runaway protection. The current lithium battery thermal runaway problem has caused great challenges to safe driving and other aspects. In the existing technology, when the lithium battery occurs thermal runaway, the temperature first reaches the abnormal heating starting temperature T1, at this time the SEI film begins to decompose, causing the anode to directly contact the electrolyte and react; then the temperature reaches the thermal runaway trigger temperature T2, which is the turning point from the slow heating zone to the fast heating zone, after which the electrolyte separator dissolves, the battery internal short circuit releases a large amount of heat; T3 is the maximum temperature reached by the battery during thermal runaway, which is related to all components of the battery. In order to meet the needs of practical application, the battery is often in the form of a unit module, so when a single battery unit module occurs thermal runaway, it is easy to affect other battery unit modules in the battery, i.e. so-called heat propagation.

[0003] Lithium battery fire and explosion is caused by internal chain reaction thermal runaway caused by battery heat propagation, so in order to avoid the spread of this catastrophic accident in the battery, the thermal safety design of the thermal runaway inducement mechanism is needed, and the existing thermal safety design mainly protects the safety of the battery module from three aspects, namely intrinsic safety design, battery system safety design and fire safety design. 1. Intrinsic safety design is considered from the safety and stability of a single battery, mainly improving the chemical composition and structure of key materials that affect the single battery, such as positive electrode material, electrolyte and separator. 2. System safety design is a comprehensive consideration of the safety performance of battery pack structure, battery itself and BMS, which takes into account the mechanical, thermal and electrical safety factors of the battery into the design process of the battery system. 3. Fire safety is a subsequent treatment measure when the battery occurs thermal runaway, which tries to minimize the damage caused by thermal runaway and controls the situation that has occurred. Intrinsic safety design is the most fundamental solution to battery module safety protection, but the current thermal protection effect is not ideal, and fire safety design is the last resort. Due to the persistence of battery unit module heat propagation, the effect of fire safety design is generally and cannot avoid damage. The most effective solution is to improve the safety of the battery unit module from the thermal safety aspect of the system safety. Because it is difficult to completely avoid the occurrence of thermal runaway of a single cell in actual working conditions, once the heat generated by it cannot be completely blocked, absorbed and absorbed, a chain reaction will occur between the battery modules, causing the entire battery to occur thermal runaway, and then fire and explosion, causing serious harm.

[0004] The inventors have found that, in order to block battery thermal runaway, the following two aspects are mainly considered: (1) dissipating the heat of battery thermal runaway to the environment in time, which is divided into active cooling and passive cooling. The active cooling includes air cooling, liquid cooling, and air cooling, etc. These schemes need to install a cooling system on the battery, and use a compressor for refrigeration. However, the power of the vehicle-mounted compressor is limited, and the refrigeration efficiency cannot cope with the instantaneous temperature rise. The passive cooling mainly uses heat pipes and various high-thermal-conductivity materials to export heat, but when the battery encounters extrusion, collision, penetration, and other unexpected situations and rapidly heats up, the effect is limited. (2) Adding a thermal barrier layer between adjacent batteries is another effective solution. One solution is to leave an air gap between adjacent battery modules as a thermal barrier layer. Experiments have shown that a gap of 5 mm can effectively interrupt heat diffusion, but in actual situations, the battery may expand due to heat, causing the gap to disappear. Another solution is to add a barrier material, such as aerogel, which can isolate heat and limit its spread to adjacent battery modules without causing serious problems. However, at high temperatures, heat can still spread to adjacent battery modules through water cooling plates or other structural components, causing thermal runaway, and further causing fires and explosions. Another solution uses heat-absorbing materials as a thermal barrier layer. Heat-absorbing materials have a certain heat content and can manage the heat safety of the battery. However, in general, the volume and weight of heat-absorbing materials in the entire battery pack are limited, and the heat-absorbing capacity of heat-absorbing materials is much lower than the heat release of the battery, which cannot achieve the purpose of inhibiting heat diffusion. Therefore, when a battery cell experiences thermal runaway, it will release a large amount of heat, and relying solely on material heat absorption cannot completely absorb the heat and prevent heat diffusion. If only insulation cannot effectively reduce the temperature, and some heat may also spread beyond the insulation layer to the non-failed battery, a protection system is needed. When a battery experiences thermal runaway, the protection system on the thermal runaway side needs to have a primary insulation function and a secondary heat absorption function to limit the heat to the thermal runaway battery as much as possible. The non-failed battery side needs to have a primary heat absorption function and a secondary insulation function to quickly absorb the small amount of heat that escapes from the liquid cooling plate and other places, and stabilize the temperature in a lower range to prevent it from failing.

[0005] The content described in the background art is for the convenience of reading and understanding the present application, and is not an admission of the prior art. In particular, the discovery and analysis of the technical problem are an important part of the improvement of the prior art by the present application.

[0006] SUMMARY

[0007] The technical problem to be solved by the present application is to provide a battery heat non-propagation protection system capable of preventing and delaying heat propagation between battery cell modules.

[0008] To solve the above technical problems, the technical scheme of the present application is as follows: a battery heat non-propagation protection system, comprising a sealed pressure-bearing shell, and a heat-absorbing material arranged in the shell, wherein the heat-absorbing material comprises water-rich, crystal water-rich or water-generating materials.

[0009] In the preferred scheme, the sealed pressure-bearing shell bears a pressure of 0.1-10 MPa.

[0010] In the preferred scheme, an elastic interlayer for heat insulation is arranged between the inner wall of the shell and the heat-absorbing material.

[0011] In the preferred scheme, the elastic interlayer comprises elastic structural members and / or elastic buffer members.

[0012] In the preferred scheme, the elastic interlayer comprises porous silica gel pads, glass fiber mats, ceramic fiber mats, melamine insulation pads, hard silica calcium plates, nano insulation plates or aerogel insulation pads.

[0013] In the preferred scheme, the nano insulation plate is a porous material containing silicon or calcium elements.

[0014] In the preferred scheme, the aerogel insulation pad is a silica aerogel insulation pad.

[0015] In the preferred scheme, the material of the shell comprises metal materials, plastics, ceramics, glass or film materials of the above materials.

[0016] In the preferred scheme, the material of the shell comprises carbon steel, stainless steel, aluminum alloy, copper alloy, PP, PE, PC, PA, PMMA, ceramics, glass or film materials of the above materials alone or in combination.

[0017] In the preferred scheme, the shell is under negative pressure or normal pressure in the initial state and is under positive pressure after being heated.

[0018] The positive pressure is 0.1-10 MPa.

[0019] In the preferred scheme, the positive pressure is 0.1-1 MPa.

[0020] In the preferred scheme, a pressure maintaining mechanism is further arranged on the shell to open the pressure relief when the pressure in the shell exceeds the preset positive pressure.

[0021] In the preferred scheme, the pressure maintaining mechanism is a pressure maintaining patch arranged on the shell, and the pressure maintaining patch is provided with a pressure mark line, and the pressure mark line is broken or the pressure maintaining patch is bonded to fail when the pressure exceeds the preset positive pressure, so as to realize pressure relief.

[0022] In a preferred embodiment, the pressure maintaining mechanism is a micropore array on the shell, and a sticking film layer is attached outside the micropore array.

[0023] When the sticking film layer fails to stick after the preset positive pressure is exceeded, the micropore array releases pressure, and the pressure is maintained by the pore diameter of the micropore array.

[0024] In a preferred embodiment, the number of micropore arrays is two or more, the positions of the micropore arrays on the shell are one or more, and the diameter of a single micropore is 1 μm to 500 μm.

[0025] In a preferred embodiment, a pressure maintaining mechanism is further provided on the shell to open the pressure release when the pressure in the shell exceeds the preset positive pressure, and to close the pressure maintaining when the pressure is lower than the preset positive pressure.

[0026] In a preferred embodiment, the structure of the pressure maintaining mechanism is that a through hole is provided on the surface of the shell, a plug is provided at the position of the through hole, the plug is used to block the through hole to achieve sealing, and on one side of the plug, the plug is connected to the shell through an elastic arm, so that the pressure maintaining mechanism opens the pressure release when the pressure exceeds the preset positive pressure, and closes the pressure maintaining when the pressure is lower than the preset positive pressure.

[0027] In a preferred embodiment, a sticking film layer is further attached outside the plug.

[0028] In a preferred embodiment, the structure of the pressure maintaining mechanism is that a valve body is provided on the shell to communicate the inner wall and the outer wall of the shell, a step or a variable diameter structure is provided in the valve body, a plug is provided at the position of the step or the variable diameter structure, an adjustable nut is provided at the free end of the valve body, and a spring is provided between the nut and the plug, so that the pressure maintaining mechanism opens the pressure release when the pressure exceeds the preset positive pressure, and closes the pressure maintaining when the pressure is lower than the preset positive pressure, and the preset positive pressure is adjustable.

[0029] In a preferred embodiment, the heat absorbing material is a hydrogel, an inorganic hydrated salt heat absorbing material, an inorganic salt heat absorbing gel material, or a chemical heat storage material.

[0030] In a preferred embodiment, the heat-absorbing material comprises a mixture of one or more of the following: sodium acetate trihydrate, ferric ammonium oxalate trihydrate, citric acid monohydrate, citric acid, oxalic acid dihydrate, oxalic acid anhydrous, 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, ferric ammonium sulfate dodecahydrate, ferrous chloride tetrahydrate, ammonium oxalate monohydrate, sodium tetraborate decahydrate, sodium tetraborate pentahydrate, aluminum sulfate octadecahydrate, ammonium pentaborate, ammonium hydrogen borate tetrahydrate, boric acid, barium hydroxide octahydrate, sodium silicate pentahydrate, sodium aluminum silicate hydrate, potassium aluminum sulfate dodecahydrate, sodium sulfate decahydrate, copper sulfate heptahydrate, ferrous sulfate heptahydrate, cobalt chloride hexahydrate, calcium sulfate dihydrate.

[0031] In a preferred embodiment, the heat-absorbing material comprises a mixture of one or more of the following: oxalic acid dihydrate, oxalic acid anhydrous, ammonium oxalate monohydrate, sodium acetate trihydrate, boric acid, ammonium pentaborate octahydrate, barium hydroxide octahydrate, sodium tetraborate decahydrate, potassium aluminum sulfate dodecahydrate, sodium sulfate decahydrate, calcium sulfate dihydrate.

[0032] In a preferred embodiment, the heat-absorbing material has a heat of fusion value of >500 J / g, an endothermic temperature of 60-400℃, and a thermal conductivity of >1 W / m.K.

[0033] In a preferred embodiment, a water cooling pipeline is arranged in the shell.

[0034] In a preferred embodiment, a groove for water cooling is arranged on the surface of the heat-absorbing material in the shell, and a waterproof coating is arranged on the surface of the groove.

[0035] In a preferred embodiment, an elastic interlayer is arranged in the shell, and a water cooling pipeline is arranged in the elastic interlayer.

[0036] Another technical problem to be solved by the present application is to provide a safe battery that can reduce or even eliminate the risk of battery fire and explosion, or reduce the loss caused by the risk of battery fire and explosion even if the risk occurs.

[0037] To solve the above technical problems, the technical solution of the present application is: a safe battery using the above battery heat non-propagation protection system, wherein the protection system is arranged between the battery units.

[0038] In a preferred embodiment, the length of one side of the protection system is not less than 30 mm, and the thickness is not less than 5 mm.

[0039] In a preferred embodiment, the length of the protection system is not less than 100 mm, the width is not less than 40 mm, and the thickness is not less than 10 mm.

[0040] In a preferred embodiment, a water cooling pipeline is arranged on the outer wall of the shell close to the battery unit.

[0041] The battery heat non-propagation protection system and the safety battery provided by the application can prevent heat propagation of the battery cell and reduce the risk of fire and explosion of the battery by adopting the combined structure of the pressure-bearing shell and the heat-absorbing material. In the preferred scheme, the protection effect of the heat protection system is under the condition of a certain positive pressure in the shell, compared with other heat protection systems under a completely normal pressure, the heat protection effect is very significant, and the other battery cells are protected during the whole process of the needle test. Through analysis, the water vapor released by the heat-absorbing material in the heat protection process is also one of the key factors of the heat protection effect. The elastic interlayer and the pressure maintaining mechanism and the combination thereof provided by the application further enhance the heat protection effect. The water cooling structure provided by the application further enhances the heat protection effect. BRIEF DESCRIPTION OF DRAWINGS

[0042] The application will be further described below in combination with the drawings and examples:

[0043] Fig. 1 is a schematic view of the cross-sectional structure of the protection system of the application.

[0044] Fig. 2 is a schematic view of the cross-sectional structure of another preferred scheme of the protection system of the application.

[0045] Fig. 3 is a schematic view of the longitudinal cross-sectional structure of the protection system of the application.

[0046] Fig. 4 is a schematic view of the longitudinal cross-sectional structure of another preferred scheme of the protection system of the application.

[0047] Fig. 5 is a schematic view of the pressure maintaining mechanism of the protection system of the application.

[0048] Fig. 6 is a schematic view of another preferred scheme of the pressure maintaining mechanism of the protection system of the application.

[0049] Fig. 7 is a schematic view of another preferred scheme of the pressure maintaining mechanism of the protection system of the application.

[0050] Fig. 8 is a schematic view of another preferred scheme of the pressure maintaining mechanism of the protection system of the application.

[0051] Fig. 9 is a differential scanning calorimetry analysis diagram of the heat-absorbing material of the application.

[0052] Fig. 10 is a schematic view of the safety battery of the application during the test.

[0053] Fig. 11 is a temperature-time curve of three temperature sensors of the first protection system of the application.

[0054] Fig. 12 is a temperature-time curve of three temperature sensors of the second protection system of the application.

[0055] Figure 13 is the protection system of the present application without pressure relief and intact.

[0056] Figure 14 is the protection system of the present application after pressure relief and burned out.

[0057] Figure 15 is a 40 times local enlarged view of the micropore array of the present application.

[0058] In the figure: housing 1, heat-absorbing material 2, elastic interlayer 3, pressure- maintaining mechanism 4, pressure-maintaining patch 401, adhesive film layer 402, plugging head 403, elastic arm 404, valve body 405, plug 406, spring 407, nut 408, micropore array 409, end plate 5, first protection system 6, battery cell 7, second protection system 8, first temperature sensor 9, fourth temperature sensor 10, second temperature sensor 11, third temperature sensor 12, fifth temperature sensor 13, sixth temperature sensor 14, needle point 15, groove 16. DETAILED DESCRIPTION

[0059] Example 1:

[0060] As shown in Figure 1, a battery heat non-propagation protection system includes a sealed pressure-bearing housing 3, and a heat-absorbing material 2 is arranged in the housing 3, and the heat-absorbing material 2 includes water-rich, crystal water-rich or water-generating materials.

[0061] In a preferred embodiment, the sealed pressure-bearing housing 3 bears a pressure of 0.1 MPa to 10 MPa.

[0062] In a preferred embodiment, the material of the housing 3 includes metal materials, plastics, ceramics, glass or film materials of the above-mentioned materials.

[0063] In a preferred embodiment, the material of the housing 3 includes carbon steel, stainless steel, aluminum alloy, copper alloy, PP, PE, PC, PA, PMMA, ceramics, glass or film materials of the above-mentioned materials alone or in combination.

[0064] In a preferred embodiment, the housing 3 is under negative pressure or normal pressure in the initial state, and is under positive pressure after being heated.

[0065] The positive pressure is 0.1 MPa to 10 MPa.

[0066] In a preferred embodiment, the positive pressure is 0.1 MPa to 1 MPa. Through experiments, considering various factors, the preferable positive pressure is 0.3 MPa to 0.6 MPa. Referring to FIG. 13, the protection system without pressure relief completely protects the entire thermal runaway process, and the adjacent battery cell 7 is not damaged, and the protection system itself is not damaged. Referring to FIG. 15, the residue after exhaust at the micropore array 409 can be seen. Referring to FIG. 14, the protection system after pressure relief delays the thermal runaway process, but fails to withstand the entire thermal runaway process, and is finally burned out after the heat absorption material 2 completely fails.

[0067] Embodiment 2:

[0068] In a preferred embodiment as shown in FIG. 2, an elastic interlayer 3 for thermal insulation is arranged between the inner wall of the shell 3 and the heat absorption material 2. The elastic interlayer 3 plays a role in thermal insulation at the initial stage of thermal runaway, and plays a role in establishing and optimizing the water vapor channel at the middle stage, effectively prolonging the protection time of thermal runaway.

[0069] In a preferred embodiment, the elastic interlayer 3 includes elastic structural members and / or elastic buffer members.

[0070] In a further preferred embodiment, the elastic interlayer 3 includes a porous silica gel pad, a glass fiber felt, a ceramic fiber felt, a melamine thermal insulation pad, a hard silica calcium plate, a nano thermal insulation plate, or an aerogel thermal insulation pad.

[0071] In a further preferred embodiment, the nano thermal insulation plate is a porous material containing silicon or calcium elements.

[0072] In a further preferred embodiment, the aerogel thermal insulation pad is a silica aerogel thermal insulation pad.

[0073] Embodiment 3:

[0074] In a preferred embodiment, a pressure maintaining mechanism 4 is further arranged on the shell 1 to open the pressure relief when the pressure in the shell 1 exceeds the preset positive pressure. The advantage of this structure is that the cost is relatively low. Considering that the protection system is a disposable device, the pressure maintaining mechanism 4 opens the pressure relief after a certain period of pressure maintaining, which can avoid the risk of explosion of the protection system itself.

[0075] In a preferred embodiment as shown in FIG. 5, the pressure maintaining mechanism 4 is a pressure maintaining patch 401 arranged on the shell 1, and the pressure maintaining patch 401 is provided with a pressure mark line. When the pressure exceeds the preset positive pressure, the pressure mark line is broken or the pressure maintaining patch 401 is bonded to fail, and the pressure relief is achieved.

[0076] In a preferred embodiment as shown in FIG. 8, the pressure maintaining mechanism 4 is a micropore array 409 arranged on the shell 1, and a bonding film layer 402 is bonded outside the micropore array 409. The bonding film layer 402 can be a metal film or a plastic film, and mainly plays a role in initial pressure maintaining.

[0077] When the adhesive film layer 402 fails to adhere after the preset positive pressure is exceeded, the micro-hole array 409 realizes pressure relief, and the pressure is maintained by the flow rate limit of the pore diameter of the micro-hole array 409.

[0078] In a preferred embodiment, the number of micro-hole arrays 409 is two or more, and the single micro-hole has a diameter of 1 μm to 500 μm. The micro-hole array 409 is preferably located at the end plate 5 at both ends of the shell 1. The micro-hole array 409 can also be located at other positions on the shell 1.

[0079] In a further preferred embodiment, a pressure maintaining mechanism 4 is further provided on the shell 1 to open the pressure relief when the pressure in the shell 1 exceeds the preset positive pressure, and to close the pressure maintaining when the pressure is lower than the preset positive pressure. By accurately maintaining the pressure, for example, the pressure is always controlled at 0.6 MPa, the risk of explosion is avoided, and the heat protection effect is better.

[0080] In an optional embodiment as shown in FIG. 6, the pressure maintaining mechanism 4 has the structure that a through hole is provided on the surface of the shell 1, a plug 403 is provided at the position of the through hole, the plug 403 is used to block the through hole to achieve sealing, and the plug 403 is connected to the shell 1 through an elastic arm 404 at one side of the plug 403, so that the pressure maintaining mechanism 4 opens the pressure relief when the pressure exceeds the preset positive pressure, and closes the pressure maintaining when the pressure is lower than the preset positive pressure.

[0081] In a preferred embodiment, an adhesive film layer 402 is further attached to the plug 403.

[0082] In another optional embodiment as shown in FIG. 7, the pressure maintaining mechanism 4 has the structure that a valve body 405 is provided on the shell 1 to communicate the inner wall and the outer wall of the shell 1, a step or a variable diameter structure is provided in the valve body 405, a plug 406 is provided at the position of the step or the variable diameter structure, an adjustable nut 408 is provided at the free end of the valve body 405, and a spring 407 is provided between the nut 408 and the plug 406, so that the pressure maintaining mechanism 4 opens the pressure relief when the pressure exceeds the preset positive pressure, and closes the pressure maintaining when the pressure is lower than the preset positive pressure, and the preset positive pressure is adjustable. The advantage of this embodiment is that the pressure maintaining pressure can be adjusted according to different types of batteries to achieve the best heat protection effect.

[0083] Example 4:

[0084] In a preferred embodiment for Examples 1 to 3, the heat absorbing material 2 is a hydrogel, an inorganic hydrated salt heat absorbing material, an inorganic salt heat absorbing gel material, or a chemical heat storage material.

[0085] In a preferred embodiment, the heat-absorbing material 2 comprises a mixture of one or more of the following: sodium acetate trihydrate, iron ammonium oxalate trihydrate, citric acid monohydrate, citric acid, oxalic acid dihydrate, oxalic acid anhydrous, 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, iron ammonium sulfate dodecahydrate, ferrous chloride tetrahydrate, ammonium oxalate monohydrate, sodium tetraborate decahydrate, sodium tetraborate pentahydrate, aluminum sulfate octadecahydrate, ammonium pentaborate, ammonium hydrogen borate tetrahydrate, boric acid, barium hydroxide octahydrate, sodium silicate pentahydrate, hydrated sodium aluminum silicate, potassium aluminum sulfate dodecahydrate, sodium sulfate decahydrate, copper sulfate heptahydrate, ferrous sulfate heptahydrate, cobalt chloride hexahydrate, calcium sulfate dihydrate.

[0086] In a preferred embodiment, the heat-absorbing material 2 comprises a mixture of one or more of the following: oxalic acid dihydrate, oxalic acid anhydrous, ammonium oxalate monohydrate, sodium acetate trihydrate, boric acid, ammonium pentaborate octahydrate, barium hydroxide octahydrate, sodium tetraborate decahydrate, potassium aluminum sulfate dodecahydrate, sodium sulfate decahydrate, calcium sulfate dihydrate.

[0087] In a preferred embodiment, the heat-absorbing material 2 has a heat of fusion value > 500 J / g, an endothermic temperature of 60-400°C, a thermal conductivity of > 1 W / m.K, and releases water-containing gas when heated.

[0088] Embodiment 4:

[0089] In a preferred embodiment, a water-cooling pipe is arranged in the shell 3. The water-cooling pipe is arranged along the length direction of the shell.

[0090] In an optional embodiment, as shown in Fig. 4, a groove 16 for water-cooling is arranged on the surface of the heat-absorbing material 2 in the shell 3, and a water-proof coating is arranged on the surface of the groove 16. This embodiment has a lower cost. The water-proof coating is preferably a water-repellent water-proof coating.

[0091] In a preferred embodiment, an elastic interlayer 3 is arranged in the shell 3, and the elastic interlayer 3 is provided with a water-cooling pipe.

[0092] Embodiment 5:

[0093] As shown in Fig. 10, a safety battery using the battery heat non-propagation protection system described above is provided with the protection system between the battery cells 7.

[0094] In a preferred embodiment, the length of one side of the protection system is not less than 30 mm, and the thickness is not less than 5 mm.

[0095] In a further preferred embodiment, the length of the protection system is not less than 100 mm, the width is not less than 40 mm, and the thickness is not less than 10 mm.

[0096] Preferably, the protective system has a length of not less than 800 mm, a width of 100 mm, and a thickness of not less than 15 mm.

[0097] Preferably, a water cooling pipe is arranged on the outer wall of the shell 3 close to the battery cell 7.

[0098] Test Example 6

[0099] As shown in Fig. 10, the first battery cell, the first protective system 6, the second battery cell, and the second protective system 8 are sequentially arranged to form a battery pack test device. A temperature sensor is arranged at each of the two ends and the middle of the first protective system 6 and the second protective system 8 close to the puncture point 15. The first temperature sensor 9, the second temperature sensor 11, the third temperature sensor 12, the fourth temperature sensor 10, the fifth temperature sensor 13, and the sixth temperature sensor 14 correspond to T1-T6 in Figs. 11 and 12, respectively. The first protective system 6 corresponds to Fig. 11, and the second protective system 8 corresponds to Fig. 12. As can be seen from Figs. 11 and 12, after the puncture operation on the battery cell 7 between the first protective system 6 and the second protective system 8 causes a fire, the first protective system 6 and the second protective system 8 start to heat up from 200 to 350 seconds, reach 600-650℃ at about 1050 seconds, and then rapidly decrease to 100-300℃ within about 10 seconds, and then keep a slow decrease or a stable state until more than 10000 seconds.

[0100] In another set of tests as shown in Figs. 13 and 14, the first protective system 6 uses a pressure maintaining mechanism 4 in the form of a pressure maintaining patch 401, and the second protective system 8 uses a pressure maintaining mechanism 4 with adjustable positive pressure. Before the battery flame is completely extinguished, the first protective system 6 is damaged, as shown in Fig. 13, and the temperature returns to the highest temperature of combustion. The second protective system 8 is basically intact, as shown in Fig. 14. However, in this test, a higher pressure maintaining pressure shows a faster temperature decrease and heat insulation effect within a time period, which is manifested as a more flat curve after the temperature decrease.

[0101] The above embodiments are only preferred technical solutions of the present application, and should not be regarded as limitations of the present application. The embodiments in the present application and the features in the embodiments can be combined with each other as long as there is no conflict. The protection scope of the present application should be based on the technical solutions recited in the claims, and include equivalent replacement solutions of the technical features recited in the claims. That is, equivalent replacement improvements within this range are also within the protection scope of the present application.

Claims

1. A battery thermal run away shield system characterized by: The application relates to a sealed pressure-bearing shell (3) provided with a heat-absorbing material (2) in the shell (3), wherein the heat-absorbing material (2) comprises water-rich, crystal water-rich or water-generating materials.

2. The battery thermal run away shield system of claim 1, wherein: The sealed pressure-bearing shell (3) bears a pressure of 0.1-10 MPa.

3. The battery thermal run away shield system of claim 1, wherein: An elastic interlayer (3) is arranged between the inner wall of the shell (3) and the heat-absorbing material (2) for heat insulation.

4. The battery thermal run away shield system of claim 3, wherein: The elastic interlayer (3) comprises elastic structural members and / or elastic buffer members.

5. The battery thermal run away shield system of claim 3, wherein: The elastic interlayer (3) comprises porous silica gel pads, glass fiber mats, ceramic fiber mats, melamine heat insulation pads, hard silica calcium plates, nano heat insulation plates or aerogel heat insulation pads.

6. The battery thermal run away shield system of claim 5, wherein: The nano heat insulation plate is a porous material containing silicon or calcium elements.

7. The battery thermal run away shield system of claim 5, wherein: The aerogel heat insulation pad is a silica aerogel heat insulation pad.

8. The battery thermal run away shield system of claim 1, wherein: The shell (3) is made of metal materials, plastics, ceramics, glass or film materials of the above materials.

9. The battery thermal run away shield system of claim 8, wherein: The shell (3) is made of carbon steel, stainless steel, aluminum alloy, copper alloy, PP, PE, PC, PA, PMMA, ceramics, glass or film materials of the above materials.

10. The battery thermal run-away prevention system according to any one of claims 1 to 9, characterized by: The shell (3) is under negative pressure or normal pressure in an initial state and is under positive pressure after being heated. The positive pressure is 0.1-10 MPa.

11. The battery thermal run away shield system of claim 10, wherein: The positive pressure is 0.1-1 MPa.

12. The battery thermal run away shield system of claim 10, wherein: A pressure maintaining mechanism (4) is further arranged on the shell (1) to open the pressure relief when the pressure in the shell (1) exceeds the preset positive pressure.

13. The battery thermal run away shield system of claim 12, wherein: The pressure maintaining mechanism (4) is a pressure maintaining patch (401) arranged on the shell (1), and the pressure maintaining patch (401) is provided with a pressure mark line.

14. The battery thermal run away shield system of claim 12, wherein: When the pressure exceeds the preset positive pressure, the pressure mark line is broken or the pressure maintaining patch (401) is bonded to fail, thereby achieving pressure relief. The pressure maintaining mechanism (4) is a micropore array (409) arranged on the shell (1), and a bonding film layer (402) is arranged outside the micropore array (409).

15. The battery thermal run away shield system of claim 12, wherein the microporous When the pressure exceeds the preset positive pressure, the bonding film layer (402) is bonded to fail, the micropore array (409) achieves pressure relief, and the pressure is maintained by the pore diameter of the micropore array (409).

16. The battery thermal run away shield system of claim 10, wherein: The number of the array (409) is more than two, the position of the array (409) on the shell (1) is more than one, and the diameter of a single micropore is 1-500 mu m.

17. The battery thermal run away shield system of claim 16, wherein: A pressure maintaining mechanism (4) is further arranged on the shell (1) to open the pressure relief when the pressure in the shell (1) exceeds the preset positive pressure and to close the pressure maintaining mechanism (4) when the pressure is lower than the preset positive pressure.

18. The battery thermal run away shield system of claim 16, wherein: The pressure maintaining mechanism (4) is arranged on the surface of the shell (1) and is provided with a through hole, and a plugging head (403) is arranged at the position of the through hole. The plugging head (403) is used for plugging the through hole to achieve sealing. The plugging head (403) is connected to the shell (1) through an elastic arm (404) on one side of the plugging head (403) to open the pressure relief when the pressure exceeds the preset positive pressure and to close the pressure maintaining mechanism (4) when the pressure is lower than the preset positive pressure. A bonding film layer (402) is further arranged outside the plugging head (403).

19. The battery thermal run away shield system of claim 16, wherein: The pressure maintaining mechanism (4) is provided with a valve body (405) communicating the inner wall and the outer wall of the shell (1), the valve body (405) is provided with a step or a variable diameter structure, the step or the variable diameter structure is provided with a plug (406), the free end of the valve body (405) is provided with an adjustable nut (408), the spring (407) is arranged between the nut (408) and the plug (406), so that the pressure maintaining mechanism (4) is opened to release pressure when the pressure exceeds the preset positive pressure, and the pressure maintaining mechanism (4) is closed when the pressure is lower than the preset positive pressure, and the preset positive pressure is adjustable.

20. The battery thermal run away protection system of claim 1 wherein: The heat-absorbing material (2) is a hydrogel, an inorganic hydrated salt heat-absorbing material, an inorganic salt heat-absorbing gel material or a chemical heat storage material.

21. The battery thermal run away protection system of claim 1 wherein: The heat-absorbing material (2) includes one or more of a mixture of sodium acetate trihydrate, ferric ammonium 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, ferric ammonium sulfate dodecahydrate, ferrous chloride tetrahydrate, ammonium oxalate monohydrate, sodium tetraborate decahydrate, sodium tetraborate pentahydrate, aluminum sulfate octadecahydrate, ammonium pentaborate, ammonium hydrogen borate tetrahydrate, boric acid, barium hydroxide octahydrate, sodium silicate pentahydrate, hydrated aluminum sodium silicate, potassium aluminum sulfate dodecahydrate, sodium sulfate decahydrate, copper sulfate heptahydrate, ferrous sulfate heptahydrate, cobalt chloride hexahydrate, calcium sulfate dihydrate.

22. The battery thermal run away protection system of claim 1 wherein: The heat-absorbing material (2) includes one or more of a mixture of oxalic acid dihydrate, anhydrous oxalic acid, ammonium oxalate monohydrate, sodium acetate trihydrate, boric acid, ammonium pentaborate octahydrate, barium hydroxide octahydrate, sodium tetraborate decahydrate, potassium aluminum sulfate dodecahydrate, sodium sulfate decahydrate, calcium sulfate dihydrate.

23. The battery thermal run away shield system of any of claims 20-22, wherein: The heat-absorbing material (2) has a heat enthalpy value of >500J / g, an endothermic temperature of 60-400℃, and a thermal conductivity of >1W / m.K.

24. The battery thermal run-away prevention system according to any one of claims 1 to 9, 11 to 22, wherein: The shell (3) is provided with a water cooling pipeline.

25. [Amended according to Rule 26 24.09.2024] The battery heat non-propagation shield system according to claim 24, characterized in that The surface of the heat-absorbing material (2) in the shell (3) is provided with a groove (16) for water cooling, and the surface of the groove (16) is provided with a waterproof coating.

26. The battery thermal run away protection system of claim 24 wherein: The shell (3) is provided with an elastic interlayer (3) provided with a water cooling pipeline.

27. A safe battery using the battery thermal run away protection system according to any one of claims 1 to 26, characterized in that, The shell (3) is provided with a protective system between the battery units (7).

28. The safe battery employing the battery heat non-propagation protection system according to claim 27, characterized by: The length of one side of the protective system is not less than 30mm, and the thickness is not less than 5mm.

29. The safe battery employing the battery thermal run away arrest system according to claim 27, wherein: The length of the protective system is not less than 100mm, the width is not less than 40mm, and the thickness is not less than 10mm.

30. The safe battery employing a battery thermal non-propagation protection system according to claim 27, wherein: The shell (3) is provided with a water cooling pipeline near the outer wall of the shell (3).

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