Battery thermal runaway protection structure

Abstract

The utility model relates to a battery thermal runaway protection structure, the battery thermal runaway protection structure comprises a heat dissipation part and a battery tray, the heat dissipation part is connected with the battery tray, the heat dissipation part is arranged between adjacent battery cell groups, and when the battery cell groups are subjected to thermal expansion, the side parts of the battery cell groups can be in contact with the heat dissipation part; and heat generated by the battery cell group can be transferred to the external space through the heat dissipation part and the battery tray. According to the battery thermal runaway protection structure provided by the invention, the problem that the thermal runaway of the battery is aggravated due to relatively low heat dissipation rate of the battery cell is solved.

Description

Technical Field

[0001] This application relates to the field of battery pack thermal protection technology, and in particular to a battery thermal runaway protection structure. Background Technology

[0002] With the increasing popularity of new energy vehicles, their safety has become a growing concern, especially the issue of battery thermal runaway.

[0003] Battery thermal runaway can be induced by external conditions such as mechanical abuse, electrical abuse, and thermal abuse. These external conditions are intrinsically linked. For example, mechanical abuse leads to deformation of individual cells, and deformation of individual cells leads to leakage of electrolyte or internal short circuits, which in turn leads to electrical abuse. Electrical abuse is accompanied by the generation of Joule heat and chemical reaction heat, causing the internal temperature of the individual cell to rise, triggering thermal runaway of the battery, and then leading to fire or even explosion.

[0004] In addition to taking fire extinguishing measures, the huge amount of heat generated by the battery cell also needs to be dissipated in time during the thermal runaway process, otherwise it will further aggravate the thermal runaway of the battery. Utility Model Content

[0005] Therefore, it is necessary to provide a battery thermal runaway protection structure to solve the problem that the low heat dissipation rate of the battery cell leads to the aggravation of battery thermal runaway.

[0006] The battery thermal runaway protection structure provided in this application includes a heat dissipation part and a battery tray. The heat dissipation part and the battery tray are connected. The heat dissipation part is disposed between adjacent battery cell groups. When the battery cell group undergoes thermal expansion, the side of the battery cell group can contact the heat dissipation part, and the heat generated by the battery cell group can be transferred to the external space through the heat dissipation part and the battery tray.

[0007] In one embodiment, the heat dissipation unit includes a first heat-conducting plate group and a second heat-conducting plate group. The first heat-conducting plate group forms a first assembly space, and the second heat-conducting plate group is located in the first assembly space and is spaced apart from the first heat-conducting plate group to form a heat insulation gap. One end of the second heat-conducting plate group is connected to the bottom wall of the battery tray, and the other end extends toward the vehicle chassis. When the battery cell group undergoes thermal expansion, the battery cell group can push the first heat-conducting plate group toward the second heat-conducting plate group and fit together through its own expansion, so that the heat generated by the battery cell group can be transferred to the battery tray in sequence through the first heat-conducting plate group and the second heat-conducting plate group.

[0008] In one embodiment, the first heat-conducting plate assembly and the bottom wall of the battery tray are spaced apart.

[0009] In one embodiment, the first heat-conducting plate group is connected to the bottom wall of the battery tray, and the first heat-conducting plate group and the battery cell group are spaced apart.

[0010] In one embodiment, the second heat-conducting plate group is arranged to form a second assembly space. The heat dissipation part also includes a heat insulation plate group. The heat insulation plate group is disposed in the second assembly space. When the battery cell group on one or both sides of the heat dissipation part undergoes thermal expansion and the second heat-conducting plate group on one or both sides of the heat insulation plate group moves toward the heat insulation plate group, the heat insulation plate group can stop between the second heat-conducting plate groups on both sides to prevent the second heat-conducting plate groups on both sides of the heat insulation plate group from exchanging heat with each other.

[0011] In one embodiment, the heat dissipation part further includes heat dissipation teeth, which are disposed in the second assembly space. One end of the side of the heat dissipation teeth is connected to the second heat conduction plate group, and the other end extends toward the heat insulation plate group. The bottom of the heat dissipation teeth is connected to the battery tray so that the heat of the second heat conduction plate group can be transferred to the battery tray through the heat dissipation teeth.

[0012] In one embodiment, the battery pack includes a plurality of battery cells arranged in parallel, with a heat dissipation buffer pad between at least some of the adjacent battery cells. When the battery cell undergoes thermal expansion, the battery cell can compress the heat dissipation buffer pad and transfer heat to the heat dissipation buffer pad.

[0013] In one embodiment, the heat dissipation buffer pad includes a first heat-absorbing layer, an elastic heat-insulating layer, and a second heat-absorbing layer stacked along the arrangement direction of the battery cells. The first and second heat-absorbing layers are used to absorb the heat generated by the battery cells, and the elastic heat-insulating layer is used to block the heat transfer between the first and second heat-absorbing layers. The elastic heat-insulating layer is capable of compression deformation along the arrangement direction of the battery cells.

[0014] In one embodiment, the heat dissipation section includes a crossbeam and a longitudinal beam. The crossbeam extends along the width direction of the battery tray, and the longitudinal beam extends along the length direction of the battery tray, so that the internal space of the battery tray is divided into multiple assembly positions by the crossbeam and longitudinal beam, and each assembly position is respectively provided with one or more battery cell groups.

[0015] In one embodiment, the heat dissipation section is installed at a height lower than the battery cell assembly, so as to form an exhaust channel between adjacent battery cell assemblies.

[0016] Compared with the prior art, the battery thermal runaway protection structure provided in this application is configured such that when the cell pack experiences thermal runaway, the thermal expansion of the cell pack causes the cell pack to come into contact with the heat dissipation unit, so that most of the heat from the cell pack can be transferred to the heat dissipation unit. Since the heat dissipation unit is connected to the battery tray, the heat generated by the cell pack can ultimately be dissipated to the external space through the battery tray. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 An exploded view of a battery thermal runaway protection structure according to an embodiment of this application;

[0019] Figure 2 A partial cross-sectional view of one of the flame-retardant heat-relieving parts in Embodiment 1 of this application;

[0020] Figure 3 A partial cross-sectional view of another flame-retardant heat-relieving part provided in Embodiment 1 of this application;

[0021] Figure 4 A partial cross-sectional view of yet another flame-retardant heat-releasing section provided in Embodiment 1 of this application;

[0022] Figure 5 This is a partial cross-sectional view of one of the flame-retardant heat-relieving parts in Embodiment 2 provided in this application;

[0023] Figure 6 A partial cross-sectional view of another flame-retardant heat-releasing part in Embodiment 2 provided in this application;

[0024] Figure 7 A partial cross-sectional view of another flame-retardant heat-releasing section in Embodiment 2 provided in this application;

[0025] Figure 8 A partial cross-sectional view of another flame-retardant heat-relieving section provided in Embodiment 2 of this application;

[0026] Figure 9 A partial structural schematic diagram of a battery thermal runaway protection structure according to an embodiment of this application;

[0027] Figure 10 for Figure 9 The enlarged view at point Q is shown below;

[0028] Figure 11 This is a schematic diagram of the structure of a heat dissipation buffer pad according to an embodiment of this application.

[0029] Reference numerals: 100, heat insulation section; 110, exhaust chamber; 200, flame-retardant heat-relieving section; 210, heat-resistant layer; 211, first fire extinguishing hole; 220, heat-conducting layer; 221, second fire extinguishing hole; 230, flame-retardant plate; 231, flame-retardant hole; 300, battery tray; 400, battery cell assembly; 410, battery cell unit; 420, heat dissipation buffer pad; 500, vehicle chassis; 600, heat dissipation section; 610, crossbeam section; 620, longitudinal beam section; 630, first heat-conducting plate assembly; 631, first assembly space; 632, heat insulation gap; 640, second heat-conducting plate assembly; 641, second assembly space; 650, heat insulation plate assembly; 660, heat dissipation fins. Detailed Implementation

[0030] With the increasing popularity of new energy vehicles, their safety has become a growing concern, especially the issue of battery thermal runaway.

[0031] Battery thermal runaway can be induced by external conditions such as mechanical abuse, electrical abuse, and thermal abuse. These external conditions are intrinsically linked. For example, mechanical abuse leads to deformation of individual cells, and deformation of individual cells leads to leakage of electrolyte or internal short circuits, which in turn leads to electrical abuse. Electrical abuse is accompanied by the generation of Joule heat and chemical reaction heat, causing the internal temperature of the individual cell to rise, triggering thermal runaway of the battery, and then leading to fire or even explosion.

[0032] Existing technical solutions typically employ battery fire suppression devices (such as fire extinguishing agents) to control battery thermal runaway. However, due to the small internal gaps within the battery, these devices struggle to completely extinguish flames generated throughout the battery. Furthermore, these devices have a limited reaction time and a failure rate, potentially allowing the fire to spread further to the vehicle's chassis or even become completely uncontrollable. Therefore, the overall effectiveness of existing technical solutions is unsatisfactory.

[0033] Please see Figures 1-8 To address the issue of unsatisfactory overall performance of existing battery thermal runaway control solutions, this application provides a battery thermal runaway protection structure. This structure includes a heat insulation part 100, an explosion-proof valve (not shown), and a flame-retardant heat-relieving part 200. The battery thermal runaway protection structure and the cell assembly 400 are all located between the vehicle chassis 500 and the battery tray 300. In other words, the vehicle chassis 500 replaces the traditional battery cover, resulting in a high degree of integration between the battery pack and the vehicle chassis 500, effectively reducing the weight of the entire battery pack.

[0034] Furthermore, along the direction from the vehicle chassis 500 to the battery tray 300, the heat insulation part 100, the explosion-proof valve, the flame-arresting heat-relieving part 200, and the battery cell assembly 400 are arranged sequentially. Specifically, the flame-arresting heat-relieving part 200 is arranged and covers the side of the battery cell assembly 400 away from the battery tray 300 to prevent the flame generated by the battery cell assembly 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 flame-arresting heat-relieving part 200 to block the heat of the flame from being transferred toward the vehicle chassis 500. The heat insulation part 100 and the flame-arresting heat-relieving part 200 are arranged at intervals to form an exhaust chamber 110. The explosion-proof valve is used to discharge the gas in the exhaust chamber 110.

[0035] This configuration, through the installation of the flame-retardant heat-relieving section 200, extinguishes the flames generated by the thermal runaway of the battery cell assembly 400, preventing the flames from spreading and causing the entire vehicle to burn. Furthermore, the high-temperature and high-pressure gases generated by the thermal runaway are discharged through the exhaust chamber 110 and the explosion-proof valve, preventing the battery cell assembly 400 from exploding. In addition, the heat insulation section 100 prevents a large amount of heat from being transferred to the chassis 500, ensuring that the temperature in the driver's cabin and passenger compartment is controllable, thereby effectively preventing the expansion of thermal runaway.

[0036] As can be seen from the above, since the flame-arresting heat-relieving part 200 covers the side of the cell assembly 400 away from the battery tray 300, the battery thermal runaway protection structure provided in this application can completely extinguish the flame generated by the cell assembly 400. Furthermore, since the flame-arresting heat-relieving part 200 is a passive flame-extinguishing device, it does not suffer from reaction delays or malfunctions, thus greatly improving the control effect during battery thermal runaway.

[0037] It is important to note that, considering the thermal redundancy design, if the highest temperature during thermal runaway of multiple battery cells is defined as Tmax, and the thermalization temperature of the carpet in the passenger compartment is defined as Td, then the withstand temperature of the insulation section 100 must be greater than or equal to Tmax. That is, the insulation temperature of the insulation section 100 must be greater than or equal to (Tmax - Td), and the insulation time t needs to exceed 1 hour. Furthermore, fire extinguishing discs, such as perfluorohexanone and dry powder fire extinguishing discs, can be attached to the side of the insulation section 100 near the explosion-proof valve. The main components of dry powder fire extinguishing discs are ammonium chloride, nitrogen, and silicates, etc., which will not be listed here.

[0038] In one embodiment, the heat insulation part 100 is a coated part, and the heat insulation part 100 is coated on the surface of the vehicle chassis 500.

[0039] Specifically, the heat insulation part 100 can be a fire-retardant and heat-insulating coating material applied to the surface of the vehicle chassis 500. This type of material contains oxides represented by the formula A2B2O7 (where A is an element selected from La, Nd, and Sr, and B is an element selected from Ti, Si, Nb, and Ta) as the main component. These materials have melting points above the operating temperature range, thermal conductivity lower than that of zirconium oxide, and thermal expansion coefficients higher than those of zirconium oxide, making them a novel type of heat-insulating coating material.

[0040] Alternatively, the heat insulation part 100 is a heat-reflective material that can reduce heat absorption and transfer by reflecting heat.

[0041] This design improves the fit between the heat insulation section 100 and the chassis 500, thereby enhancing the heat insulation performance.

[0042] In another embodiment, the heat insulation part 100 is an aerogel felt.

[0043] In this way, not only can the weight of the entire battery structure be reduced, but the heat insulation effect of the heat insulation part 100 can also be improved.

[0044] In other embodiments, the material of the heat insulation part 100 may also be glass fiber, asbestos, rock wool, silicate and vacuum plate, etc., which will not be listed here.

[0045] Example 1

[0046] Please see Figures 2-4 In this embodiment, the flame-retardant heat-relieving part 200 is a single-plate structure, and the flame-retardant heat-relieving part 200 includes a heat-resistant layer 210 disposed on the side near the battery cell assembly 400 and a heat-conducting layer 220 disposed on the side near the heat insulation part 100. The heat-resistant layer 210 and the heat-conducting layer 220 are tightly attached, 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 sequentially.

[0047] Furthermore, the heat-resistant layer 210 is provided with a plurality of through-hole first fire extinguishing holes 211, and the heat-conducting layer 220 is provided with a plurality of through-hole second fire extinguishing holes 221. The first fire extinguishing holes 211 and the second fire extinguishing holes 221 are connected, and the flow area of ​​the second fire extinguishing hole 221 is smaller than the flow area of ​​the first fire extinguishing hole 211.

[0048] It should be noted that the first fire extinguishing hole 211 and the second fire extinguishing hole 221 can be of uniform size or non-uniform size.

[0049] Thus, when the high-temperature flame begins to rise, since the flame-retardant heat-relieving part 200 is provided with a heat-resistant layer 210 on the side near the battery pack 400, it can be ensured that the flame-retardant heat-relieving part 200 itself will not be damaged under high-temperature burning.

[0050] Afterwards, the flames rise upwards through the first extinguishing hole 211. Since the first extinguishing hole 211 is located on the heat-resistant layer 210, the total area of ​​the multiple first extinguishing holes 211 is obviously smaller than the area of ​​the heat-resistant layer 210. Therefore, after the flames enter the first extinguishing hole 211 from the space between the flame-retardant heat-releasing part 200 and the battery cell assembly 400, the flames will become more concentrated and the burning area of ​​the flames will shrink.

[0051] Subsequently, since the second extinguishing hole 221 connects to the first extinguishing hole 211, the flame continues to rise along the second extinguishing hole 221. Because the flow area of ​​the second extinguishing hole 221 is smaller than that of the first extinguishing hole 211, the burning area of ​​the flame is further reduced, and the flame becomes more concentrated. Furthermore, because the second extinguishing hole 221 is located within the heat-conducting layer 220, a large amount of heat generated by the flame is dissipated through the heat-conducting layer 220, causing the flame temperature to drop rapidly, thus making the flame smaller and smaller or even completely extinguished.

[0052] Furthermore, since the thermal conductivity of air, the thermal conductivity of heat-resistant layer 210 and the thermal conductivity of heat-conducting layer 220 increase sequentially, the heat transfer rate of the flame along the side of the flame-retardant heat-releasing part 200 toward the exhaust chamber 110 is accelerated.

[0053] 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 board (VIP) and aerogel, etc., which will not be listed here one by one.

[0054] Similarly, in one embodiment, the material of the thermal conductive layer 220 includes, but is not limited to, silicon carbide ceramics, high-temperature alloys, ceramic fibers, and ceramic matrix composites, etc., which will not be listed here.

[0055] In one embodiment, such as Figure 2 and Figure 3 As shown, the direction along 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.

[0056] Given that the flow area of ​​the second fire extinguishing hole 221 is smaller than that of the first fire extinguishing hole 211, it can be concluded that the first fire extinguishing hole 211 can completely cover the second fire extinguishing hole 221. Correspondingly, the solid part of the heat-conducting 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-conducting layer 220 through the inner wall around the second fire extinguishing hole 221, so that heat can be transferred to the heat-conducting layer 220.

[0057] Furthermore, in one embodiment, as Figure 2 As shown, both the first fire extinguishing hole 211 and the second fire extinguishing hole 221 are cylindrical holes, and the first fire extinguishing hole 211 and the second fire extinguishing hole 221 are coaxially arranged.

[0058] This helps to reduce the processing difficulty of the flame-retardant heat-relieving part 200.

[0059] Furthermore, in another embodiment, such as 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 tips of the first fire extinguishing hole 211 and the second fire extinguishing hole 221 both face the vehicle chassis 500. 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 walls of the first fire extinguishing hole 211 and the second fire extinguishing hole 221 are smoothly connected.

[0060] This design allows the flame to make uniform contact with the inner wall around the second fire extinguishing hole 221 when it enters the second fire extinguishing hole 221, thereby improving the heat dissipation uniformity of the heat-conducting layer 220.

[0061] In another embodiment, such as 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.

[0062] This increases the contact area between the heat-conducting layer 220 and the flame, improving the heat dissipation effect.

[0063] Example 2

[0064] Please see Figures 5-8 In this embodiment, the flame-arresting and heat-relieving part 200 is a multi-layer plate structure. The flame-arresting and heat-relieving part 200 includes a plurality of flame-arresting plates 230 stacked sequentially along the battery cell assembly 400 to the vehicle chassis 500. Each flame-arresting plate 230 is provided with a plurality of flame-arresting holes 231, and the flame-arresting holes 231 on adjacent flame-arresting plates 230 are connected to form a flame-arresting channel.

[0065] Each flame arrestor plate 230 has a thermal conductivity greater than that of air, and the thermal conductivity of multiple flame arrestor plates 230 tends to increase along the direction from the battery cell assembly 400 to the vehicle chassis 500.

[0066] Specifically, considering exhaust characteristics and electrical safety, the diameter D1 of the first layer of flame arrestor hole 231 directly above the battery cell assembly 400, the outer diameter D2 of the explosion-proof valve, and the distance D3 between the positive and negative electrodes of the battery cell satisfy D1≥D2 and D1≤(D3-2mm).

[0067] The distance L1 from the flame retardant plate 230 to the battery cell group 400 is L1≥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 between the two, 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.

[0068] With such a setting, through the successive weakening of the flame by the multiple flame retardant holes 231, the flame can be extinguished at the fastest speed. Moreover, since the flame retardant holes 231 on the 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 rapidly drop, thereby resulting in the self - extinction of the flame.

[0069] Moreover, since the thermal conductivity coefficient 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 coefficient of the flame retardant plate 230 shows an increasing trend. Therefore, as the flame continues to rise, the greater the decrease in the flame temperature, and at this time, it is more conducive to the extinction of the flame.

[0070] In one embodiment, as Figure 5 shown, the adjacent flame retardant plates 230 are arranged in a fitting manner.

[0071] With such a setting, the volume of the entire flame retardant and heat release part 200 can be reduced, thereby reducing the assembly volume of the battery thermal runaway protection structure.

[0072] In another embodiment, as Figure 6 shown, the adjacent flame retardant plates 230 are arranged at intervals.

[0073] With such a setting, when the flame enters the space 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 dispersed. 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.

[0074] In one embodiment, as Figure 5 and Figure 6 shown, the flame retardant holes 231 of the adjacent flame retardant plates 230 are arranged in a one - to - one correspondence and connected, and along the direction from the battery cell group 400 to the vehicle body chassis 500, the flow - through area of the flame retardant holes 231 on each flame retardant plate 230 shows a decreasing trend.

[0075] With such a setting, the contraction of the flame is better, and when the size of the flame retardant hole 231 is small enough, the flame will no longer be able to propagate.

[0076] In another embodiment, such as Figure 7 As shown, the flame-arresting hole 231 on the side of the flame-arresting plate 230 closest to the battery cell assembly 400 is defined as the proximal hole, and the flame-arresting hole 231 on the side of the flame-arresting plate 230 closest to the vehicle chassis 500 is defined as the distal hole. Each proximal hole 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.

[0077] With this configuration, as the flame rises, the inner diameter of the flame arrestor hole 231 will decrease exponentially. At this time, the flame will be divided into countless very small flame streams, so that the flame arrestor plate 230 can quickly absorb the heat of the flame.

[0078] In yet another embodiment, such as Figure 8 As shown, the fire-arresting holes 231 of adjacent fire-arresting plates 230 are staggered, and each fire-arresting hole 231 is connected to two fire-arresting holes 231 on the adjacent fire-arresting plates 230.

[0079] This design allows the flame to be continuously diverted and cross-flowed, gradually extinguishing the flame during the process.

[0080] In addition to taking fire extinguishing measures, the huge amount of heat generated by the battery cell also needs to be dissipated in time during the thermal runaway process, otherwise it will further aggravate the thermal runaway of the battery.

[0081] Please see Figures 9-11 To address the problem of low heat dissipation rate of battery cells leading to increased battery thermal runaway, in one embodiment, the battery thermal runaway protection structure further includes a heat dissipation part 600. The heat dissipation part 600 is connected to the battery tray 300, and is disposed 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 part 600, allowing the heat generated by the battery cell group 400 to be transferred to the external space through the heat dissipation part 600 and the battery tray 300.

[0082] With this configuration, when the cell assembly 400 experiences thermal runaway, the thermal expansion of the cell assembly 400 causes it to come into contact with the heat dissipation unit 600, allowing most of the heat from the cell assembly 400 to be transferred to the heat dissipation unit 600. Since the heat dissipation unit 600 is connected to the battery tray 300, the heat generated by the cell assembly 400 can ultimately be dissipated to the external space through the battery tray 300.

[0083] In one embodiment, such as Figure 9As shown, the heat dissipation unit 600 includes a crossbeam 610 and a longitudinal beam 620. The crossbeam 610 extends along the width direction of the battery tray 300, and the longitudinal beam 620 extends along the length direction of the battery tray 300, so that the internal space of the battery tray 300 is divided into multiple assembly positions by the crossbeam 610 and the longitudinal beam 620, and each assembly position is respectively provided with a cell assembly 400.

[0084] It should be noted that either the crossbeam 610 can cut off the longitudinal beam 620, or the longitudinal beam 620 can cut off the crossbeam 610.

[0085] This prevents heat from flowing between adjacent battery cell groups 400.

[0086] In one embodiment, the installation height of the heat dissipation section 600 (the height of the protrusion of the battery tray 300 toward the vehicle chassis 500) is lower than the installation height of the cell pack 400, so that an exhaust channel is formed between adjacent cell packs 400.

[0087] This design helps to accelerate the flow of gas into the exhaust channels on both sides of the battery tray 300.

[0088] Specifically, in one embodiment, such as Figure 10 As shown, the heat dissipation unit 600 includes a first heat-conducting plate group 630 and a second heat-conducting plate group 640. The first heat-conducting plate group 630 surrounds and forms 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 insulation gap 632. 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 vehicle chassis 500.

[0089] When the battery cell assembly 400 expands, there are two scenarios. In the first scenario, when the battery cell assembly 400 undergoes thermal expansion, it pushes the first heat-conducting plate assembly 630 towards the second heat-conducting plate assembly 640, causing them to come into contact with each other. In the second scenario, when the battery cell assembly 400 expands during normal charging and discharging, the expansion force and internal resistance are relatively small in the early stages. At this time, although the battery cell assembly 400 pushes the first heat-conducting plate assembly 630 towards the second heat-conducting plate assembly 640, the two are not in contact. Towards the end of the cycle life, the expansion force and internal resistance of the battery cell assembly 400 increase, causing it to push the first heat-conducting plate assembly 630 towards the second heat-conducting plate assembly 640, causing them to come into contact with each other.

[0090] The force and position of the first heat-conducting plate group 630 contacting the second heat-conducting plate group 640 can be set according to the following requirements: 1. Valve opening pressure when the battery cell group 400 experiences thermal runaway; 2. Cyclic expansion force curve of the battery cell group 400; 3. Change in internal resistance of the battery cell group 400 during the cycle.

[0091] It should be noted that the first heat-conducting plate group 630 can be in the shape of a square, forming the first assembly space 631. Alternatively, the first heat-conducting plate group 630 can be in the shape of a double-headed slit, with the first heat-conducting plate group 630 and the side wall of the battery tray 300 forming the first assembly space 631.

[0092] 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.

[0093] When the cell assembly 400 undergoes thermal expansion, the cell assembly 400 can push the first heat-conducting plate assembly 630 toward and fit against the second heat-conducting plate assembly 640 through its own expansion, so that the heat generated by the cell assembly 400 can be transferred to the battery tray 300 in sequence through the first heat-conducting plate assembly 630 and the second heat-conducting plate assembly 640.

[0094] It should be noted that the first heat-conducting plate group 630 and the second heat-conducting plate group 640 can be made of heat-conducting metal materials such as aluminum alloy, copper alloy or iron alloy, which will not be listed here.

[0095] As can be seen from the above, when the battery cell assembly 400 does not undergo thermal expansion, since the second heat-conducting plate assembly 640 and the first heat-conducting plate assembly 630 are spaced apart and the second heat-conducting plate assembly 640 is located in the first assembly space 631, that is, the battery cell assembly 400 and the second heat-conducting plate assembly 640 do not directly contact each other. This helps to prevent the battery cell assembly 400 from losing a large amount of heat during normal operation.

[0096] When the battery cell assembly 400 undergoes thermal expansion, the battery cell assembly 400 can push the first heat-conducting plate assembly 630 toward and fit against the second heat-conducting plate assembly 640 through its own expansion. At this time, the heat generated by the battery cell assembly 400 can be transferred to the battery tray 300 in sequence through the first heat-conducting plate assembly 630 and the second heat-conducting plate assembly 640, which greatly improves the heat dissipation efficiency of the heat dissipation part 600.

[0097] The ingenuity of this solution lies in the fact that when the 400-cell pack is operating normally, heat will not be lost in large quantities, but when the 400-cell pack undergoes thermal expansion, the heat can be dissipated in a timely manner.

[0098] However, this is not the only embodiment; in other embodiments, the heat dissipation unit 600 may also be integrally formed.

[0099] Furthermore, in one embodiment, the bottom walls of the first heat-conducting plate assembly 630 and the battery tray 300 are spaced apart.

[0100] This helps prevent heat loss from the battery cell assembly 400 through the first heat-conducting plate assembly 630 during normal operation. The first heat-conducting plate assembly 630 can be connected to the battery cell assembly 400 or to the side wall of the battery tray 300.

[0101] 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.

[0102] This design also helps prevent the heat from the battery cell assembly 400 from being lost through the first heat-conducting plate assembly 630 during normal operation.

[0103] To ensure structural strength and insulation, the gap between the first heat-conducting plate group 630 and the cell group 400 can be filled with non-thermal insulating structural components, including but not limited to structural adhesives and elastic components.

[0104] In one embodiment, such as Figure 10 As shown, the second heat-conducting plate group 640 surrounds to form the second assembly space 641. The heat dissipation part 600 also includes a heat insulation plate group 650. The heat insulation plate group 650 is disposed in the second assembly space 641. When the battery cell group 400 on one or both sides of the heat dissipation part 600 undergoes thermal expansion, and the second heat-conducting plate group 640 located on one or both sides of the heat insulation plate group 650 moves toward the heat insulation plate group 650, the heat insulation plate group 650 can stop 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 insulation plate group 650 from escaping heat between each other.

[0105] It should be noted that the second heat-conducting plate group 640 can be in the shape of a square, forming the second assembly space 641, or it can be in the shape of a two-character. The second heat-conducting plate group 640 and the side wall of the battery tray 300 form the second assembly space 641.

[0106] This design avoids heat transfer between battery cell groups 400, which could affect adjacent battery cell groups 400, thus greatly improving the heat dissipation safety of the heat dissipation unit 600.

[0107] Furthermore, in one embodiment, as Figure 9 and Figure 10 As shown, the heat dissipation unit 600 also includes heat dissipation teeth 660, which are disposed in the second assembly space 641. One end of the side of the heat dissipation teeth 660 is connected to the second heat conduction plate group 640, and the other end extends toward the heat insulation plate group 650. The bottom of the heat dissipation teeth 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 teeth 660.

[0108] This configuration further improves the heat dissipation efficiency of the heat sink 600.

[0109] Furthermore, the heat dissipation teeth 660 have two rows, which extend along the length of the heat insulation plate assembly 650, and adjacent heat dissipation teeth 660 in each row are spaced apart.

[0110] In one embodiment, such as Figures 9-11 As shown, the battery cell assembly 400 includes a plurality of battery cell units 410 arranged in parallel. At least some of the adjacent battery cell units 410 are provided with heat dissipation buffer pads 420. When the battery cell unit 410 undergoes thermal expansion, the battery cell unit 410 can compress the heat dissipation buffer pad 420 and transfer heat to the heat dissipation buffer pad 420.

[0111] This can mitigate the thermal expansion and thermal runaway of the battery cell 410.

[0112] Specifically, the heat dissipation cushioning pad is either in the shape of a U-shaped frame or a flat plate.

[0113] It should be noted that the total thickness D of the heat dissipation buffer pad 420 should take into account the cyclic expansion stress σ of the battery cell 410, the compression ratio K of the heat dissipation buffer pad 420, and the thermal insulation performance of the heat dissipation buffer pad 420.

[0114] Furthermore, in one embodiment, the heat dissipation buffer pad 420 includes a first heat-absorbing layer (not shown), an elastic heat-insulating layer (not shown), and a second heat-absorbing layer (not shown) stacked along the arrangement direction of the battery cells 410. The first heat-absorbing layer and the second heat-absorbing layer are used to absorb the heat generated by the battery cells 410, and the elastic heat-insulating layer is used to block the heat transfer between the first heat-absorbing layer and the second heat-absorbing layer. The elastic heat-insulating layer can undergo compression deformation along the arrangement direction of the battery cells 410.

[0115] This configuration improves the heat dissipation and cushioning effect of the heat dissipation pad 420.

[0116] It should be noted that the heat absorption capacity of the first and second heat absorption layers should be determined based on the energy Q = C × m × t generated from the self-generating heat 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).

[0117] Specifically, in one embodiment, the first heat-absorbing layer and the second heat-absorbing layer are provided with heat-absorbing phase change materials such as refrigerant, or the first heat-absorbing layer and the second heat-absorbing layer are made of metal thermally conductive materials.

[0118] Furthermore, the elastic insulation layer is made of aerogel material, or it is made of polyurethane foam or polyethylene foam.

[0119] In another embodiment, the heat dissipation buffer pad 420 is an elastic thermally conductive component, including but not limited to thermally conductive silicone and thermally conductive silicone cloth, etc., which will not be listed here.

[0120] Furthermore, in one embodiment, the heat dissipation cushion 420 also includes a support layer (not shown) to support the entire heat dissipation cushion 420.

[0121] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above 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.

[0122] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the patent protection scope of this application should be determined by the appended claims.

[0123] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0124] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0125] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0126] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0127] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0128] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Claims

1. A battery thermal runaway protection structure, characterized in that, It includes a heat dissipation part (600) and a battery tray (300), the heat dissipation part (600) and the battery tray (300) are connected, the heat dissipation part (600) is disposed 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 part (600), and the heat generated by the battery cell group (400) can be transferred to the external space through the heat dissipation part (600) and the battery tray (300).

2. The battery thermal runaway protection structure according to claim 1, characterized in that, The heat dissipation unit (600) includes a first heat-conducting plate group (630) and a second heat-conducting plate group (640). The first heat-conducting plate group (630) surrounds and forms 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 insulation gap (632). 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 vehicle chassis (500). When the cell assembly (400) undergoes thermal expansion, the cell assembly (400) can push the first heat-conducting plate assembly (630) toward the second heat-conducting plate assembly (640) and fit together through its own expansion, so that the heat generated by the cell assembly (400) can be transferred to the battery tray (300) in sequence through the first heat-conducting plate assembly (630) and the second heat-conducting plate assembly (640).

3. The battery thermal runaway protection structure according to claim 2, characterized in that, The bottom walls of the first heat-conducting plate assembly (630) and the battery tray (300) are spaced apart.

4. The battery thermal runaway protection structure according to claim 2, characterized in that, 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 cell group (400) are spaced apart.

5. The battery thermal runaway protection structure according to claim 2, characterized in that, The second heat-conducting plate group (640) surrounds to form a second assembly space (641). The heat dissipation part (600) also includes a heat insulation plate group (650). The heat insulation plate group (650) is disposed in the second assembly space (641). When the cell group (400) on one or both sides of the heat dissipation part (600) undergoes thermal expansion, and the second heat-conducting plate group (640) located on one or both sides of the heat insulation plate group (650) moves toward the heat insulation plate group (650), the heat insulation plate group (650) can stop 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 insulation plate group (650) from mutually transmitting heat.

6. The battery thermal runaway protection structure according to claim 5, characterized in that, The heat dissipation part (600) further includes heat dissipation teeth (660), which are disposed in the second assembly space (641). One end of the side of the heat dissipation teeth (660) is connected to the second heat-conducting plate group (640), and the other end extends toward the heat insulation plate group (650). The bottom of the heat dissipation teeth (660) is connected to the battery tray (300) so that the heat of the second heat-conducting plate group (640) can be transferred to the battery tray (300) through the heat dissipation teeth (660).

7. The battery thermal runaway protection structure according to claim 1, characterized in that, The battery cell assembly (400) includes a plurality of battery cell units (410) arranged in parallel. At least some of the adjacent battery cell units (410) are provided with heat dissipation buffer pads (420). When the battery cell unit (410) undergoes thermal expansion, the battery cell unit (410) can compress the heat dissipation buffer pads (420) and transfer heat to the heat dissipation buffer pads (420).

8. The battery thermal runaway protection structure according to claim 7, characterized in that, The heat dissipation buffer pad (420) includes a first heat-absorbing layer, an elastic heat-insulating layer and a second heat-absorbing layer stacked along the arrangement direction of the battery cells (410). The first heat-absorbing layer and the second heat-absorbing layer are used to absorb the heat generated by the battery cells (410). The elastic heat-insulating layer is used to block the heat transfer between the first heat-absorbing layer and the second heat-absorbing layer. The elastic heat-insulating layer can be compressed and deformed along the arrangement direction of the battery cells (410).

9. The battery thermal runaway protection structure according to claim 1, characterized in that, The heat dissipation section (600) includes a crossbeam section (610) and a longitudinal beam section (620). The crossbeam section (610) extends along the width direction of the battery tray (300), and the longitudinal beam section (620) extends along the length direction of the battery tray (300), so that the internal space of the battery tray (300) is divided into multiple assembly positions by the crossbeam section (610) and the longitudinal beam section (620) arranged in a cross manner. Each assembly position is respectively provided with one or more battery cell groups (400).

10. The battery thermal runaway protection structure according to claim 1, characterized in that, The heat dissipation section (600) is installed at a height lower than that of the battery cell group (400) so that an exhaust channel is formed between adjacent battery cell groups (400).

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