Battery thermal runaway protection structure

Abstract

The invention relates to a battery thermal runaway protection structure, the battery thermal runaway protection structure comprises a heat insulation part, an explosion-proof valve and a fire-retardant heat release part, and the fire-retardant heat release part is arranged and covers one side, deviating from a battery tray, of a battery cell group so as to prevent flame generated by the battery cell group from spreading towards a vehicle body chassis; the heat insulation part is arranged on the side, facing the fire-retardant heat release part, of the vehicle body chassis so as to prevent heat of flames from being transmitted to the vehicle body chassis, the heat insulation part and the fire-retardant heat release part are arranged at intervals to form an exhaust cavity, and the anti-explosion valve is used for exhausting gas in the exhaust cavity. According to the battery thermal runaway protection structure provided by the invention, the problem that the overall effect of an existing battery thermal runaway control scheme is poor is solved.

Description

Technical Field

[0001] The present application relates to the technical field of thermal protection of battery packs, and in particular to a battery thermal runaway protection structure. Background Art

[0002] With the popularization of new energy vehicles, the safety of new energy vehicles has received more and more attention, especially the thermal runaway problem of batteries, which has become the focus of people's attention.

[0003] Thermal runaway of batteries may be induced by external conditions such as mechanical abuse, electrical abuse and thermal abuse. These external conditions are intrinsically linked. For example, mechanical abuse causes deformation of single cells, and deformation of single cells leads to leakage of electrolyte or internal short circuit, which in turn leads to electrical abuse. Electrical abuse is accompanied by the generation of Joule heat and chemical reaction heat, which causes the internal heat of single cells to increase, triggering thermal runaway of the battery, and then fire or even explosion.

[0004] In the existing technical solutions, battery fire extinguishing devices (such as fire extinguishing agents, etc.) are usually added to control the thermal runaway of the battery. However, due to the small gaps inside the battery, it is difficult for the fire extinguishing device to completely extinguish the flames generated in various parts of the battery. In addition, the fire extinguishing device has a certain reaction time and failure rate, which may cause the fire to spread further to the chassis of the vehicle body or even completely out of control. Therefore, it can be seen that the overall effect of the existing technical solutions is not good. Summary of the invention

[0005] Based on this, it is necessary to provide a battery thermal runaway protection structure to solve the problem that the existing solutions for controlling battery thermal runaway have poor overall effects.

[0006] The battery thermal runaway protection structure provided in the present application includes a heat insulation part, an explosion-proof valve and a fire-blocking and heat-releasing part. The fire-blocking and heat-releasing part is arranged and covered on the side of the battery cell group away from the battery tray to prevent the flame generated by the battery cell group from spreading toward the vehicle body chassis. The heat insulation part is arranged on the side of the vehicle body chassis facing the fire-blocking and heat-releasing part to prevent the heat of the flame from being transferred toward the vehicle body chassis. The heat insulation part and the fire-blocking and heat-releasing part are arranged at intervals to form an exhaust cavity, and the explosion-proof valve is used to discharge the gas in the exhaust cavity.

[0007] In one embodiment, the fire-resistant and heat-releasing part is a single-plate structure, and the fire-resistant and heat-releasing part includes a heat-resistant layer arranged on the side close to the battery cell group and a heat-conductive layer arranged on the side close to the insulation part, the heat-resistant layer and the heat-conductive layer are arranged in close contact with each other, and the thermal conductivity of the air, the thermal conductivity of the heat-resistant layer and the thermal conductivity of the heat-conductive layer increase sequentially; the heat-resistant layer is provided with a plurality of first fire-extinguishing holes arranged through it, and the heat-conductive layer is provided with a plurality of second fire-extinguishing holes arranged through it, the first fire-extinguishing holes and the second fire-extinguishing holes are connected, and the flow area of ​​the second fire-extinguishing holes is smaller than the flow area of ​​the first fire-extinguishing holes.

[0008] In one of the embodiments, the direction from the heat-resistant layer to the heat-conductive layer is defined as the preset direction, and the orthographic projection of the first fire extinguishing hole on the plane perpendicular to the preset direction completely covers the orthographic projection of the second fire extinguishing hole on the plane perpendicular to the preset direction.

[0009] In one embodiment, the first fire extinguishing hole and the second fire extinguishing hole are coaxially arranged conical holes, and the conical tip of the first fire extinguishing hole and the conical tip of the second fire extinguishing hole are both facing the vehicle body chassis, and the minimum inner diameter of the first fire extinguishing hole is equal to the maximum inner diameter of the second fire extinguishing hole.

[0010] In one of the embodiments, along the direction from the heat-resistant layer to the heat-conducting layer, the first fire-extinguishing hole and the second fire-extinguishing hole are partially staggered.

[0011] In one of the embodiments, the fire-blocking and heat-releasing portion is a multi-layer plate structure, and the fire-blocking and heat-releasing portion includes a plurality of fire-blocking plates stacked in sequence from the battery cell group to the vehicle body chassis, each fire-blocking plate is respectively provided with a plurality of fire-blocking holes, and the fire-blocking holes on adjacent fire-blocking plates are correspondingly connected to form a fire-blocking channel; the thermal conductivity of each fire-blocking plate is greater than the thermal conductivity of the air, and along the direction from the battery cell group to the vehicle body chassis, the thermal conductivity of the plurality of fire-blocking plates tends to increase.

[0012] In one embodiment, adjacent fire-blocking boards are arranged in close proximity; or, adjacent fire-blocking boards are arranged at intervals.

[0013] In one of the embodiments, the fire-blocking holes of adjacent fire-blocking plates are arranged one by one and connected, and the flow area of ​​the fire-blocking holes on each fire-blocking plate tends to decrease along the direction from the battery cell group to the vehicle body chassis.

[0014] In one of the embodiments, the fire blocking holes on the fire blocking plates on the side close to the battery cell group among adjacent fire blocking plates are defined as proximal holes, and the fire blocking holes on the fire blocking plates on the side close to the vehicle body chassis among adjacent fire blocking plates are defined as distal holes, each proximal hole corresponds to and is connected to multiple distal holes, and the flow area of ​​the proximal hole is greater than the sum of the flow areas of the corresponding multiple distal holes.

[0015] In one embodiment, the fire blocking holes of adjacent fire blocking plates are staggered, and each fire blocking hole is connected to two fire blocking holes on adjacent fire blocking plates.

[0016] Compared with the prior art, the battery thermal runaway protection structure provided by the present application is configured in such a way that, by providing a fire-blocking and heat-releasing part, the flame generated by the thermal runaway of the battery cell group is extinguished, thereby preventing the flame from continuing to spread and causing the entire vehicle to burn. In addition, the high-temperature and high-pressure gas generated by the thermal runaway is discharged through the exhaust chamber and the explosion-proof valve to avoid the explosion of the battery cell group. Furthermore, through the barrier effect of the insulation part, a large amount of heat is prevented from being transferred to the vehicle chassis, thereby ensuring that the temperature in the cockpit and the passenger compartment is controllable, thereby effectively avoiding the expansion of thermal runaway.

[0017] From the above, it can be seen that since the fire-blocking and heat-releasing part covers the side of the battery pack away from the battery tray, the battery thermal runaway protection structure provided by the present application can completely extinguish the flame generated by the battery pack. In addition, since the fire-blocking and heat-releasing part is a passive flameout device, the fire-blocking and heat-releasing part does not have the problem of delayed reaction and failure to operate, thereby greatly improving the control effect of the battery thermal runaway. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 An exploded view of a battery thermal runaway protection structure according to an embodiment of the present application; Figure 2 A partial cross-sectional view of one of the fire-blocking and heat-releasing parts of the first embodiment provided in the present application; Figure 3 A partial cross-sectional view of another fire-blocking and heat-releasing portion of the first embodiment provided in the present application; Figure 4 A partial cross-sectional view of yet another fire-blocking and heat-releasing portion of the first embodiment provided in the present application; Figure 5 A partial cross-sectional view of a fire-blocking and heat-releasing portion of the second embodiment provided in the present application; Figure 6 A partial cross-sectional view of another fire-blocking and heat-releasing portion of the second embodiment provided in the present application; Figure 7 A partial cross-sectional view of yet another fire-blocking and heat-releasing portion of the second embodiment provided in the present application; Figure 8 A partial cross-sectional view of another fire-blocking and heat-releasing portion of the second embodiment provided in the present application; Fig. 9 A schematic diagram of a partial structure of a battery thermal runaway protection structure according to an embodiment of the present application; Fig.10 for Fig. 9 A magnified view of Q is shown; Fig.11 A schematic structural diagram of a heat dissipation buffer pad according to an embodiment of the present application.

[0020] : Figure numerals: 100, insulation part; 110, exhaust chamber; 200, fire-blocking and heat-releasing part; 210, heat-resistant layer; 211, first fire-extinguishing hole; 220, heat-conducting layer; 221, second fire-extinguishing hole; 230, fire-blocking plate; 231, fire-blocking hole; 300, battery tray; 400, battery cell group; 410, battery cell unit; 420, heat dissipation buffer pad; 500, vehicle body chassis; 600, heat dissipation part; 610, cross beam part; 620, longitudinal beam part; 630, first heat-conducting plate group; 631, first assembly space; 632, insulation gap; 640, second heat-conducting plate group; 641, second assembly space; 650, insulation plate group; 660, heat dissipation teeth. DETAILED DESCRIPTION

[0021] With the popularization of new energy vehicles, the safety of new energy vehicles has received more and more attention, especially the thermal runaway problem of batteries, which has become the focus of people's attention.

[0022] Thermal runaway of batteries may be induced by external conditions such as mechanical abuse, electrical abuse and thermal abuse. These external conditions are intrinsically linked. For example, mechanical abuse causes deformation of single cells, and deformation of single cells leads to leakage of electrolyte or internal short circuit, which in turn leads to electrical abuse. Electrical abuse is accompanied by the generation of Joule heat and chemical reaction heat, which causes the internal heat of single cells to increase, triggering thermal runaway of the battery, and then fire or even explosion.

[0023] In the existing technical solutions, battery fire extinguishing devices (such as fire extinguishing agents, etc.) are usually added to control the thermal runaway of the battery. However, due to the small gaps inside the battery, it is difficult for the fire extinguishing device to completely extinguish the flames generated in various parts of the battery. In addition, the fire extinguishing device has a certain reaction time and failure rate, which may cause the fire to spread further to the chassis of the vehicle body or even completely out of control. Therefore, it can be seen that the overall effect of the existing technical solutions is not good.

[0024] See also Figure 1-Figure 8 In order to solve the problem that the existing solutions for controlling battery thermal runaway have poor overall effects, the present application provides a battery thermal runaway protection structure, which includes a heat insulation portion 100, an explosion-proof valve (not shown) and a fire-blocking and heat-releasing portion 200. The battery thermal runaway protection structure and the battery cell group 400 are all arranged between the vehicle chassis 500 and the battery pack lower cover. That is to say, the vehicle chassis 500 replaces the traditional battery upper cover, so that the battery pack and the vehicle chassis 500 are highly integrated, effectively reducing the weight of the entire battery pack.

[0025] In addition, along the direction from the vehicle chassis 500 to the lower cover of the battery pack, the heat insulation part 100, the explosion-proof valve, the fire-blocking and heat-releasing part 200 and the battery pack 400 are sequentially arranged. Specifically, the fire-blocking and heat-releasing part 200 is arranged and covers the side of the battery pack 400 away from the battery tray 300, so as to prevent the flame generated by the battery pack 400 from spreading toward the vehicle chassis 500, the heat insulation part 100 is arranged on the side of the vehicle chassis 500 facing the fire-blocking and heat-releasing part 200, so as to prevent the heat of the flame from being transferred toward the vehicle chassis 500, the heat insulation part 100 and the fire-blocking and heat-releasing part 200 are arranged at intervals to form an exhaust cavity 110, and the explosion-proof valve is used to discharge the gas in the exhaust cavity 110.

[0026] In this way, by providing the flame-blocking and heat-releasing part 200, the flame generated by the thermal runaway of the battery pack 400 is extinguished, preventing the flame from continuing to spread and causing the entire vehicle to burn. In addition, the high-temperature and high-pressure gas generated by the thermal runaway is discharged through the exhaust chamber 110 and the explosion-proof valve to avoid the explosion of the battery pack 400. Furthermore, through the barrier effect of the insulation part 100, a large amount of heat is prevented from being transferred to the vehicle body chassis 500, ensuring that the temperature in the cockpit and the passenger compartment is controllable, thereby effectively avoiding the expansion of thermal runaway.

[0027] As can be seen from the above, since the fire-blocking heat-releasing part 200 covers the side of the battery pack 400 away from the battery tray 300, the battery thermal runaway protection structure provided by the present application can completely extinguish the flame generated by the battery pack 400. In addition, since the fire-blocking heat-releasing part 200 is a passive flameout device, the fire-blocking heat-releasing part 200 does not have the problem of delayed reaction and failure to operate, thereby greatly improving the control effect of the battery thermal runaway.

[0028] Moreover, when no open flame is generated during the thermal runaway process, the battery thermal runaway protection structure provided in the present application can also enhance the heat dissipation capacity and guide the high-temperature gas to be exhausted through the exhaust cavity 110 between the fire-blocking and heat-releasing part 200 and the insulation part 100, thereby avoiding hazards such as short circuit and overheating caused by the escape of high-temperature gas between the battery cell groups 400.

[0029] It should be noted that, considering the redundant design of thermal insulation, the maximum temperature of multiple battery cells during thermal runaway is defined as Tmax, and the thermalization temperature of the carpet in the passenger compartment is Td. The tolerance temperature of the thermal insulation part 100 must be greater than or equal to Tmax, that is, the thermal insulation temperature of the thermal insulation part 100 must be greater than or equal to (Tmax-Td), and the thermal insulation time t must exceed 1h. In addition, a fire extinguishing sheet, such as perfluorohexanone and dry powder fire extinguishing sheet, can be attached to the side of the thermal insulation part 100 close to the explosion-proof valve. The main components of the dry powder fire extinguishing sheet are ammonium chloride, nitrogen and silicate, etc., which are not listed here one by one.

[0030] In one embodiment, the heat insulating portion 100 is a coating member, and the heat insulating portion 100 is coated on the surface of the vehicle body chassis 500 .

[0031] Specifically, the heat insulation part 100 may be a fireproof heat insulation coating material and applied to the surface of the vehicle chassis 500. Such a material contains a composition of (where A is an element selected from La, Nd, Sr, and B is an element selected from Ti, Si, Nb, and Ta) as the main body. These materials have a melting point higher than the operating temperature range, a thermal conductivity lower than that of zirconia, and a thermal expansion coefficient greater than that of zirconia, and are a new type of thermal insulation coating material.

[0032] Alternatively, the heat insulating part 100 is a heat reflective material, which can reduce the absorption and transfer of heat by reflecting heat.

[0033] Such an arrangement can improve the fit between the heat insulating portion 100 and the vehicle body chassis 500, thereby enhancing the heat insulating performance.

[0034] In another embodiment, the thermal insulation part 100 is an aerogel felt.

[0035] In this way, not only the weight of the entire battery structure can be reduced, but also the heat insulation effect of the heat insulation part 100 can be improved.

[0036] In other embodiments, the insulation part 100 may be made of glass fiber, asbestos, rock wool, silicate, vacuum board, etc., which are not listed here one by one.

[0037] Embodiment 1 See also Figure 2-Figure 4 In this embodiment, the fire-resistant heat-releasing portion 200 is a single-plate structure, and the fire-resistant heat-releasing portion 200 includes a heat-resistant layer 210 arranged on a side close to the battery cell group 400 and a heat-conducting layer 220 arranged on a side close to the heat-insulating portion 100. The heat-resistant layer 210 and the heat-conducting layer 220 are closely attached to each other, and the thermal conductivity of the air, the thermal conductivity of the heat-resistant layer 210, and the thermal conductivity of the heat-conducting layer 220 increase in sequence.

[0038] In addition, the heat-resistant layer 210 is provided with a plurality of first fire extinguishing holes 211 which are arranged through the heat-resistant layer 210, and the heat-conductive layer 220 is provided with a plurality of second fire extinguishing holes 221 which are arranged through the heat-conducting layer 220. The first fire extinguishing holes 211 and the second fire extinguishing holes 221 are connected and the flow area of ​​the second fire extinguishing holes 221 is smaller than the flow area of ​​the first fire extinguishing holes 211.

[0039] It should be noted that the first fire extinguishing hole 211 and the second fire extinguishing hole 221 may be of uniform size or of non-uniform size.

[0040] In this way, when the high temperature flame begins to rise, since the side of the flame retardant and heat radiating part 200 close to the battery cell group 400 is provided with the heat resistant layer 210, it can be ensured that the flame retardant and heat radiating part 200 itself will not be damaged under the condition of high temperature burning.

[0041] Afterwards, the flame rises upward through the first fire extinguishing hole 211. Since the first fire extinguishing hole 211 is arranged in the heat-resistant layer 210, the total area of ​​the multiple first fire extinguishing holes 211 is obviously smaller than the area of ​​the heat-resistant layer 210. Therefore, after the flame enters the first fire extinguishing hole 211 from the space between the fire-blocking heat-releasing part 200 and the battery cell group 400, the flame will be more concentrated and the burning area of ​​the flame will be reduced.

[0042] Afterwards, since the second fire extinguishing hole 221 is connected to the first fire extinguishing hole 211, the flame continues to rise along the second fire extinguishing hole 221. Since the flow area of ​​the second fire extinguishing hole 221 is smaller than the flow area of ​​the first fire extinguishing hole 211, the burning area of ​​the flame is further reduced, and the flame is more concentrated. In addition, since the second fire extinguishing hole 221 is arranged on the heat conducting layer 220, the heat generated by the flame is largely dissipated through the heat conducting layer 220, so that the flame temperature drops rapidly, and then the flame becomes smaller and smaller or even completely extinguished.

[0043] Furthermore, since the thermal conductivity of air, the thermal conductivity of the heat-resistant layer 210 and the thermal conductivity of the heat-conducting layer 220 increase successively, the heat that is beneficial to the flame will be transferred faster along the flame-blocking heat-releasing portion 200 toward one side of the exhaust cavity 110 .

[0044] Furthermore, in one embodiment, the material of the heat-resistant layer 210 includes but is not limited to glass wool, rock wool, polyurethane foam, extruded polystyrene foam board (XPS), vacuum insulation panel (VIP) and aerogel, etc., which are not listed here one by one.

[0045] Likewise, in one embodiment, the material of the heat conducting layer 220 includes but is not limited to silicon carbide ceramics, high temperature alloys, ceramic fibers, ceramic matrix composite materials, etc., which are not listed here one by one.

[0046] In one embodiment, if Figure 2 and Figure 3 As shown, the direction from the heat-resistant layer 210 to the heat-conducting layer 220 is defined as the preset direction, and the orthographic projection of the first fire extinguishing hole 211 on the plane perpendicular to the preset direction completely covers the orthographic projection of the second fire extinguishing hole 221 on the plane perpendicular to the preset direction.

[0047] Considering that the flow area of ​​the second fire extinguishing hole 221 is smaller than the flow area of ​​the first fire extinguishing hole 211, it can be known that the first fire extinguishing hole 211 can completely cover the second fire extinguishing hole 221. Correspondingly, the solid part of the heat conductive plate around the first fire extinguishing hole 211 can cover the solid part of the heat resistant plate around the second fire extinguishing hole 221. In this way, after the flame enters the second fire extinguishing hole 221 from the first fire extinguishing hole 211, it can contact the heat conductive layer 220 through the inner wall around the second fire extinguishing hole 221, so as to facilitate heat transfer to the heat conductive layer 220.

[0048] Further, in one embodiment, if Figure 2 As shown, the first fire extinguishing hole 211 and the second fire extinguishing hole 221 are both cylindrical holes, and the first fire extinguishing hole 211 and the second fire extinguishing hole 221 are coaxially arranged.

[0049] This is helpful to reduce the difficulty of processing the fire-blocking and heat-radiating portion 200 .

[0050] Furthermore, in another embodiment, Figure 3 As shown, the first fire extinguishing hole 211 and the second fire extinguishing hole 221 are coaxially arranged conical holes, and the conical tip of the first fire extinguishing hole 211 and the conical tip of the second fire extinguishing hole 221 are both facing the vehicle body chassis 500, and the minimum inner diameter of the first fire extinguishing hole 211 is equal to the maximum inner diameter of the second fire extinguishing hole 221, so that the inner wall of the first fire extinguishing hole 211 and the inner wall of the second fire extinguishing hole 221 are smoothly connected.

[0051] Such an arrangement allows the flame to evenly contact the inner walls around the second fire extinguishing hole 221 when entering the second fire extinguishing hole 221 , thereby improving the heat dissipation uniformity of the heat conductive layer 220 .

[0052] In another embodiment, if Figure 4 As shown, along the direction from the heat-resistant layer 210 to the heat-conducting layer 220 , the first fire-extinguishing hole 211 and the second fire-extinguishing hole 221 are partially staggered, that is, partially staggered while maintaining communication.

[0053] In this way, the contact area between the heat conductive layer 220 and the flame can be increased, thereby improving the heat dissipation effect.

[0054] Embodiment 2 See also Figure 5-Figure 8 In this embodiment, the fire-blocking and heat-releasing portion 200 is a multi-layer plate structure, and the fire-blocking and heat-releasing portion 200 includes a plurality of fire-blocking plates 230 stacked in sequence from the battery cell group 400 to the vehicle body chassis 500, each fire-blocking plate 230 is respectively provided with a plurality of fire-blocking holes 231, and the fire-blocking holes 231 on adjacent fire-blocking plates 230 are correspondingly connected to form a fire-blocking channel.

[0055] The thermal conductivity of each flame retardant plate 230 is greater than that of air, and along the direction from the battery cell group 400 to the vehicle body chassis 500, the thermal conductivity of the multiple flame retardant plates 230 shows an increasing trend.

[0056] Specifically, considering the exhaust characteristics and electrical safety, the diameter D1 of the first layer of flame retardant holes 231 directly above the battery cell group 400, the outer diameter D2 of the explosion-proof valve, and the distance D3 between the positive and negative electrodes of the battery cells satisfy D1≥D2 and D1≤(D3 - 2 mm).

[0057] The distance L1 from the flame retardant plate 230 to the battery cell group 400 is ≥2 mm, the sum L2 of the thickness of the flame retardant plate 230, the thickness of the heat insulation part 100, and the gap of the exhaust cavity 110 therebetween, and the distance L3 from the battery cell group 400 to the vehicle body chassis 500 satisfy L2 < L3 / 2, or L2 < 5 mm, and the smaller value is taken.

[0058] With such a setting, through the successive weakening of the flame by the multiple layers of flame retardant holes 231, the flame can be extinguished at the fastest speed. And because the flame retardant holes 231 on adjacent flame retardant plates 230 are correspondingly connected to form a flame retardant channel, when the flame enters the flame retardant channel, it will be divided into many small flame streams. These flame retardant channels have a high heat transfer capacity, causing the flame temperature to drop rapidly, thereby causing the flame to go out by itself.

[0059] Moreover, since the thermal conductivity of each flame retardant plate 230 is greater than that of air, and along the direction from the battery cell group 400 to the vehicle body chassis 500, the thermal conductivity of the flame retardant plate 230 shows an increasing trend. Therefore, as the flame continues to rise, the greater the drop in the flame temperature, and at this time, it is more conducive to the extinguishment of the flame.

[0060] In one embodiment, as Figure 5 shown, the adjacent flame retardant plates 230 are arranged in a fitting manner.

[0061] With such a setting, the volume of the entire flame retardant and heat release part 200 can be reduced, and the assembly volume of the battery thermal runaway protection structure can be reduced.

[0062] In another embodiment, as Figure 6 shown, the adjacent flame retardant plates 230 are arranged at intervals.

[0063] With such a setting, when the flame enters between the adjacent flame retardant plates 230, since the space between the adjacent flame retardant plates 230 suddenly increases compared with the flame retardant holes 231, the flame will be sharply dispersed. At this time, the heat of the flame will be dissipated. When the dispersed flame enters the flame retardant holes 231 of the next flame retardant plate 230 again, the flame will be further divided into smaller flame streams. In this way, the extinguishing effect of the flame is better.

[0064] In one embodiment, as Figure 5 and Figure 6 As shown, the fire-blocking holes 231 of adjacent fire-blocking plates 230 are arranged one by one and connected, and the flow area of ​​the fire-blocking holes 231 on each fire-blocking plate 230 tends to decrease along the direction from the battery cell group 400 to the vehicle body chassis 500.

[0065] Such an arrangement makes the flame more shrinkable, and when the size of the fire-blocking hole 231 is reduced to a certain extent, the flame will not be able to continue to spread.

[0066] In another embodiment, if Figure 7 As shown, the fire blocking hole 231 on the fire blocking plate 230 near the battery cell group 400 among adjacent fire blocking plates 230 is defined as a proximal hole, and the fire blocking hole 231 on the fire blocking plate 230 near the vehicle body chassis 500 among adjacent fire blocking plates 230 is defined as a distal hole, each proximal hole corresponds to and connects multiple distal holes, and the flow area of ​​the proximal hole is greater than the sum of the flow areas of the corresponding multiple distal holes.

[0067] With such arrangement, as the flame rises, the inner diameter of the fire-blocking hole 231 will decrease exponentially, and at this time, the flame will be divided into countless very small flame flows, so that the fire-blocking plate 230 can quickly absorb the heat of the flame.

[0068] In yet another embodiment, Figure 8 As shown, the fire blocking holes 231 of adjacent fire blocking plates 230 are staggered, and each fire blocking hole 231 is connected to two fire blocking holes 231 on adjacent fire blocking plates 230 .

[0069] Such an arrangement enables the flame to be continuously cross-divided, and in the process of cross-dividing, the flame is gradually extinguished.

[0070] During the thermal runaway process of the battery, in addition to taking fire-fighting measures, the huge heat generated by the battery cells also needs to be dissipated in a timely manner, otherwise it will further aggravate the thermal runaway of the battery.

[0071] See also Figure 9-11 In order to solve the problem that the low heat dissipation rate of the battery cell leads to aggravated thermal runaway of the battery, in one embodiment, the battery thermal runaway protection structure also includes a heat dissipation portion 600, the heat dissipation portion 600 is connected to the battery tray 300, and the heat dissipation portion 600 is arranged between adjacent battery cell groups 400. When the battery cell group 400 undergoes thermal expansion, the side of the battery cell group 400 can contact the heat dissipation portion 600, and the heat generated by the battery cell group 400 can be transferred to the external space through the heat dissipation portion 600 and the battery tray 300.

[0072] With such arrangement, when thermal runaway occurs in the battery cell group 400, the thermal expansion of the battery cell group 400 is utilized to make the battery cell group 400 contact with the heat dissipation portion 600, so that most of the heat of the battery cell group 400 can be transferred to the heat dissipation portion 600. Because the heat dissipation portion 600 is connected to the battery tray 300, the heat generated by the battery cell group 400 can eventually be dissipated to the external space through the battery tray 300.

[0073] In one embodiment, if Fig. 9 As shown, the heat dissipation portion 600 includes a cross beam portion 610 and a longitudinal beam portion 620. The cross beam portion 610 extends along the width direction of the battery tray 300, and the longitudinal beam portion 620 extends along the length direction of the battery tray 300, so that the internal space of the battery tray 300 is divided into a plurality of assembly positions by the cross-arranged cross beam portions 610 and the longitudinal beam portions 620, and each assembly position corresponds to a battery cell group 400.

[0074] It should be noted that the cross beam portion 610 may cut off the longitudinal beam portion 620 , or the longitudinal beam portion 620 may cut off the cross beam portion 610 .

[0075] In this way, heat transfer between adjacent battery cell groups 400 can be prevented.

[0076] In one embodiment, the height of the heat dissipation portion 600 (the height protruding from the battery tray 300 toward the vehicle chassis 500 ) is lower than the height of the battery cell groups 400 , so that an exhaust channel is formed between adjacent battery cell groups 400 .

[0077] Such a configuration is helpful to speed up the process of guiding the gas into the gas outlet channels on both sides of the battery tray 300 .

[0078] Specifically, in one embodiment, if Fig.10 As shown, the heat dissipation part 600 includes a first heat conducting plate group 630 and a second heat conducting plate group 640. The first heat conducting plate group 630 is surrounded to form a first assembly space 631. The second heat conducting plate group 640 is located in the first assembly space 631 and is spaced apart from the first heat conducting plate group 630 to form a heat insulating gap 632. Moreover, one end of the second heat conducting plate group 640 is connected to the bottom wall of the battery tray 300, and the other end extends toward the direction close to the vehicle body chassis 500.

[0079] It should be noted that the first heat conductive plate group 630 can be in a U-shape, enclosing a first assembly space 631 , or the first heat conductive plate group 630 can be in a R-shape, with the first heat conductive plate group 630 and the side wall of the battery tray 300 enclosing a first assembly space 631 .

[0080] Specifically, the first heat conducting plate group 630 and the second heat conducting plate group 640 are made of metal heat conducting materials or heat conducting ceramics.

[0081] When the battery cell group 400 undergoes thermal expansion, the battery cell group 400 can push the first heat conductive plate group 630 to move toward and fit the second heat conductive plate group 640 through its own expansion, so that the heat generated by the battery cell group 400 can be transferred to the battery tray 300 through the first heat conductive plate group 630 and the second heat conductive plate group 640 in sequence.

[0082] From the above, it can be seen that when the battery cell group 400 does not undergo thermal expansion, since the second heat conductive plate group 640 is spaced apart from the first heat conductive plate group 630 and the second heat conductive plate group 640 is located in the first assembly space 631, that is, there is no direct contact between the battery cell group 400 and the second heat conductive plate group 640, this is helpful in preventing a significant loss of heat from occurring during normal operation of the battery cell group 400.

[0083] When the battery cell group 400 undergoes thermal expansion, the battery cell group 400 can push the first heat conductive plate group 630 to move toward and fit the second heat conductive plate group 640 through its own expansion. At this time, the heat generated by the battery cell group 400 can be transferred to the battery tray 300 through the first heat conductive plate group 630 and the second heat conductive plate group 640 in sequence, that is, the heat dissipation efficiency of the heat dissipation part 600 is greatly improved.

[0084] The cleverness of this solution is that when the battery cell group 400 operates normally, the heat will not be lost in large quantities, but when the battery cell group 400 expands thermally, the heat can be dissipated in time.

[0085] But not limited to this, in other embodiments, the heat dissipation portion 600 can also be an integrally formed arrangement.

[0086] Furthermore, in one embodiment, the first heat conducting plate group 630 and the bottom wall of the battery tray 300 are spaced apart.

[0087] This helps prevent the heat of the battery pack 400 from being lost through the first heat conducting plate group 630 when the battery pack 400 is operating normally. At this time, the first heat conducting plate group 630 can be connected to the battery pack 400 or to the side wall of the battery tray 300.

[0088] In another embodiment, the first heat conducting plate group 630 is connected to the bottom wall of the battery tray 300 , and the first heat conducting plate group 630 and the battery cell group 400 are spaced apart.

[0089] Such a configuration is also helpful to prevent the heat of the battery cell group 400 from being lost through the first heat conducting plate group 630 when the battery cell group 400 is operating normally.

[0090] In one embodiment, if Fig.10As shown, the second heat conducting plate group 640 is arranged to form a second assembly space 641, and the heat dissipation part 600 also includes a heat insulating plate group 650, and the heat insulating plate group 650 is arranged in the second assembly space 641. When the battery cell group 400 on one side or both sides of the heat dissipation part 600 undergoes thermal expansion, and the second heat conducting plate group 640 located on one side or both sides of the heat insulating plate group 650 moves toward the heat insulating plate group 650, the heat insulating plate group 650 can be stopped between the second heat conducting plate groups 640 on both sides to prevent the second heat conducting plate groups 640 located on both sides of the heat insulating plate group 650 from radiating heat to each other.

[0091] It should be noted that the second heat conductive plate group 640 can be in a U-shape, enclosing a second assembly space 641 , or the second heat conductive plate group 640 can be in a R-shape, with the second heat conductive plate group 640 and the side wall of the battery tray 300 enclosing a second assembly space 641 .

[0092] Such an arrangement can prevent the heat between the battery cell groups 400 from being transferred to each other so as to affect the adjacent battery cell groups 400 , thereby greatly improving the heat dissipation safety of the heat dissipation portion 600 .

[0093] Further, in one embodiment, if Fig. 9 and Fig.10 As shown, the heat dissipation part 600 also includes a heat dissipation tooth 660, which is arranged in the second assembly space 641, one end of the side of the heat dissipation tooth 660 is connected to the second heat conduction plate group 640, and the other end extends toward the insulation plate group 650, and the bottom of the heat dissipation tooth 660 is connected to the battery tray 300, so that the heat of the second heat conduction plate group 640 can be transferred to the battery tray 300 through the heat dissipation tooth 660.

[0094] Such an arrangement further improves the heat dissipation efficiency of the heat dissipation unit 600 .

[0095] Furthermore, the heat dissipation teeth 660 have two rows, and the two rows of heat dissipation teeth 660 extend along the length direction of the heat insulation plate group 650 respectively, and the heat dissipation teeth 660 adjacent to each row are arranged at intervals.

[0096] In one embodiment, if Figure 9-11 As shown, the battery cell group 400 includes a plurality of battery cell units 410 arranged in parallel, and a heat dissipation buffer pad 420 is provided between at least some adjacent battery cell units 410. When the battery cell units 410 undergo thermal expansion, the battery cell units 410 can compress the heat dissipation buffer pad 420 and transfer heat to the heat dissipation buffer pad 420.

[0097] In this way, thermal expansion and thermal runaway of the battery cell unit 410 can be mitigated.

[0098] Specifically, the heat dissipation buffer pad 420 is in the shape of a circular frame or a flat plate.

[0099] It should be noted that the total thickness D of the heat dissipation buffer 420 should take into account the cyclic expansion stress σ of the battery cell unit 410 , the compression ratio K of the heat dissipation buffer 420 , and the thermal insulation performance of the heat dissipation buffer 420 .

[0100] Furthermore, in one embodiment, the heat dissipation buffer 420 includes a first heat absorption layer (not shown), an elastic heat insulation layer (not shown) and a second heat absorption layer (not shown) stacked along the arrangement direction of the battery cell units 410. The first heat absorption layer and the second heat absorption layer are used to absorb the heat generated by the battery cell units 410. The elastic heat insulation layer is used to block the heat transfer between the first heat absorption layer and the second heat absorption layer, and the elastic heat insulation layer can be compressively deformed along the arrangement direction of the battery cell units 410.

[0101] Such configuration can improve the heat dissipation and buffering effects of the heat dissipation buffer pad 420 .

[0102] It should be noted that the heat absorption capacity of the first heat absorption layer and the second heat absorption layer is determined according to the energy Q=C×m×t generated from the self-heating temperature T1 (critical temperature) to T2 (trigger temperature) in the ARC curve of the battery cell, where C is the specific heat capacity which can be measured by the isothermal adiabatic method, m is the mass, and t is (T2-T1).

[0103] Specifically, in one embodiment, heat absorbing phase change materials such as refrigerant are provided inside the first heat absorbing layer and the second heat absorbing layer, or the first heat absorbing layer and the second heat absorbing layer are made of metal heat conductive materials.

[0104] Furthermore, the elastic heat insulation layer is made of aerogel material, or the elastic heat insulation layer is polyurethane foam or polyethylene foam.

[0105] In another embodiment, the heat dissipation buffer pad 420 is an elastic heat conductive member, including but not limited to thermal conductive silicone and thermal conductive silicone cloth, etc., which are not listed here one by one.

[0106] Furthermore, in one embodiment, the heat dissipation buffer pad 420 further includes a support layer (not shown) to support the entire heat dissipation buffer pad 420 .

[0107] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0108] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the scope of patent protection of the present application shall be subject to the attached claims.

[0109] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0110] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0111] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0112] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0113] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0114] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

Claims

1. A battery thermal runaway protection structure, characterized in that: The invention comprises a heat insulating part (100), an explosion-proof valve and a fire-blocking heat-releasing part (200); the fire-blocking heat-releasing part (200) is arranged and covers a side of a battery cell group (400) facing away from a battery tray (300) to prevent the flame generated by the battery cell group (400) from spreading toward a vehicle chassis (500); the heat insulating part (100) is arranged on a side of the vehicle chassis (500) facing the fire-blocking heat-releasing part (200) to prevent the heat of the flame from being transferred toward the vehicle chassis (500); the heat insulating part (100) and the fire-blocking heat-releasing part (200) are arranged at intervals to form an exhaust cavity (110); and the explosion-proof valve is used to discharge gas in the exhaust cavity (110).

2. The battery thermal runaway protection structure according to claim 1, characterized in that: The fire-resistant heat-releasing portion (200) is a single-plate structure, and the fire-resistant heat-releasing portion (200) comprises a heat-resistant layer (210) arranged on a side close to the battery cell group (400) and a heat-conducting layer (220) arranged on a side close to the heat-insulating portion (100), the heat-resistant layer (210) and the heat-conducting layer (220) being arranged in close contact with each other, and the thermal conductivity of air, the thermal conductivity of the heat-resistant layer (210), and the thermal conductivity of the heat-conducting layer (220) increase in sequence; The heat-resistant layer (210) is provided with a plurality of first fire-extinguishing holes (211) extending therethrough, and the heat-conducting layer (220) is provided with a plurality of second fire-extinguishing holes (221) extending therethrough, the first fire-extinguishing holes (211) and the second fire-extinguishing holes (221) being connected to each other, and a flow area of ​​the second fire-extinguishing holes (221) is smaller than a flow area of ​​the first fire-extinguishing holes (211).

3. The battery thermal runaway protection structure according to claim 2, characterized in that: A direction from the heat-resistant layer (210) to the heat-conducting layer (220) is defined as a preset direction, and an orthographic projection of the first fire-extinguishing hole (211) on a plane perpendicular to the preset direction completely covers an orthographic projection of the second fire-extinguishing hole (221) on a plane perpendicular to the preset direction.

4. The battery thermal runaway protection structure according to claim 3, characterized in that: The first fire extinguishing hole (211) and the second fire extinguishing hole (221) are coaxially arranged conical holes, and the conical tip of the first fire extinguishing hole (211) and the conical tip of the second fire extinguishing hole (221) are both facing the vehicle body chassis (500), and the minimum inner diameter of the first fire extinguishing hole (211) is equal to the maximum inner diameter of the second fire extinguishing hole (221).

5. The battery thermal runaway protection structure according to claim 2, characterized in that: Along the direction from the heat-resistant layer (210) to the heat-conducting layer (220), the first fire-extinguishing hole (211) and the second fire-extinguishing hole (221) are partially staggered.

6. The battery thermal runaway protection structure according to claim 1, characterized in that: The fire-blocking and heat-releasing portion (200) is a multi-layer plate structure, comprising a plurality of fire-blocking plates (230) stacked in sequence from the battery cell group (400) to the vehicle chassis (500), each of the fire-blocking plates (230) being provided with a plurality of fire-blocking holes (231), and the fire-blocking holes (231) on adjacent fire-blocking plates (230) being connected to each other to form a fire-blocking channel; The thermal conductivity of each fire-blocking plate (230) is greater than the thermal conductivity of air, and along the direction from the battery cell group (400) to the vehicle chassis (500), the thermal conductivity of the plurality of fire-blocking plates (230) tends to increase.

7. The battery thermal runaway protection structure according to claim 6, characterized in that: The adjacent fire-blocking plates (230) are arranged in close proximity; Alternatively, adjacent fire-blocking plates (230) are arranged at intervals.

8. The battery thermal runaway protection structure according to claim 6, characterized in that: The fire-blocking holes (231) of adjacent fire-blocking plates (230) are arranged in one-to-one correspondence and are connected, and along the direction from the battery cell group (400) to the vehicle chassis (500), the flow area of ​​the fire-blocking hole (231) on each fire-blocking plate (230) tends to decrease.

9. The battery thermal runaway protection structure according to claim 6, characterized in that: The fire blocking hole (231) on the fire blocking plate (230) on the side close to the battery cell group (400) among the adjacent fire blocking plates (230) is defined as a proximal hole, and the fire blocking hole (231) on the fire blocking plate (230) on the side close to the vehicle body chassis (500) among the adjacent fire blocking plates (230) is defined as a distal hole, each of the proximal holes is connected to a plurality of the distal holes, and a flow area of ​​the proximal hole is greater than the sum of the flow areas of the corresponding plurality of the distal holes.

10. The battery thermal runaway protection structure according to claim 6, characterized in that: The fire-blocking holes (231) of adjacent fire-blocking plates (230) are arranged in a staggered manner, and each of the fire-blocking holes (231) is respectively connected to two fire-blocking holes (231) on adjacent fire-blocking plates (230).

Images