A floor assembly, battery box and power battery

Abstract

The present invention belongs to the technical field of power batteries and discloses a base plate assembly, a battery box and a power battery. The base plate assembly is used to support battery cells. An explosion-proof valve is provided at the bottom end of the battery cell. A pressure relief chamber and a heat exchange channel are formed in the base plate assembly. A connecting hole corresponding to the explosion-proof valve is provided on the top surface of the base plate assembly. A heat exchange liquid is contained in the heat exchange channel. The heat exchange channel includes a heat exchange inlet and a heat exchange outlet. The heat exchange inlet is connected to the connecting hole, and the heat exchange outlet is connected to the pressure relief chamber. Both the heat exchange inlet and the heat exchange outlet are provided with a waterproof breathable membrane. The airflow generated after thermal runaway of the battery cell first enters the heat exchange channel through the connecting hole, exchanges heat with the heat exchange liquid for cooling, and then is discharged through the pressure relief chamber. This can quickly reduce the temperature of the thermal runaway gas and prevent heat from spreading and causing safety accidents. The heat exchange inlet and the heat exchange outlet are both provided with a waterproof breathable membrane, which can allow airflow to pass through and prevent liquid flow to prevent the heat exchange liquid in the heat exchange channel from flowing out.

Description

Technical Field

[0001] The present invention relates to the technical field of power batteries, and in particular to a floor assembly, a battery box and a power battery. Background Art

[0002] With the rapid expansion and development of the new energy market, the market share of new energy vehicles has gradually increased, and consumers are increasingly inclined to choose new energy vehicles. Because of this, people are paying more and more attention to and having higher requirements for the core components of new energy vehicles, namely power batteries. Not only do they need power batteries to provide good power performance, but they also need power batteries to have extremely superior stability, so that they can ensure the personal safety of passengers even in the event of emergencies.

[0003] Traditional thermal runaway design solutions are ineffective in cooling the entire battery pack after a single battery cell runs away, which can easily lead to heat spreading within the battery pack, posing a safety hazard. Summary of the Invention

[0004] The object of the present invention is to provide a floor assembly, a battery box and a power battery that can effectively control the temperature of the airflow during thermal runaway, prevent heat from spreading, and thus improve the safety level of the power battery.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A base plate assembly is used to support a battery cell. An explosion-proof valve is provided at the bottom end of the battery cell. A pressure relief chamber and a heat exchange channel are formed in the base plate assembly. A connecting hole corresponding to the explosion-proof valve is provided on the top surface of the base plate assembly. A heat exchange liquid is contained in the heat exchange channel. The heat exchange channel includes a heat exchange inlet and a heat exchange outlet. The heat exchange inlet is connected to the connecting hole, and the heat exchange outlet is connected to the pressure relief chamber. Both the heat exchange inlet and the heat exchange outlet are provided with waterproof and breathable membranes.

[0007] As an optional solution of the above-mentioned bottom plate assembly, the waterproof and breathable membrane is made of polytetrafluoroethylene, thermoplastic polyurethane elastomer, thermoplastic polyolefin or ethylene-vinyl acetate copolymer.

[0008] As an optional solution of the above-mentioned base plate assembly, the heat exchange channel is arranged in the pressure relief cavity.

[0009] As an optional solution of the above-mentioned bottom plate assembly, the bottom plate assembly includes a bottom guard plate and a top plate that are stacked and connected, the pressure relief cavity is surrounded by the bottom guard plate and the top plate, the connecting hole is provided on the top plate, and the bottom guard plate includes a convex portion protruding toward the top plate, and the heat exchange flow channel is formed in the convex portion.

[0010] As an optional solution of the above-mentioned bottom plate assembly, the top surface of the convex portion is provided with the heat exchange inlet, and the side surface of the convex portion is provided with the heat exchange outlet;

[0011] And / or, the top plate is a cold plate, a cooling cavity is formed in the cold plate, and the cooling cavity is used for circulating a cooling medium.

[0012] As an optional solution for the above-mentioned bottom plate assembly, the top surface of the protrusion abuts against the top plate, and the two side surfaces of the protrusion in the opposite length direction are respectively enclosed with the bottom guard plate and the top plate to form two sub-pressure relief chambers, so that the thermal runaway gas can be discharged in two opposite directions.

[0013] As an optional solution of the above-mentioned floor assembly, a diaphragm is provided at the communication hole, and the diaphragm is configured to leak out of the communication hole under the action of thermal runaway gas of the battery cell and to seal the communication hole when the battery cell is in a normal state.

[0014] A battery box, comprising:

[0015] A box frame, wherein a pressure relief port is provided on the box frame;

[0016] The above-mentioned bottom plate assembly is connected to the bottom end of the box frame and encloses a cavity for accommodating the battery cell;

[0017] The connecting surfaces of the bottom plate assembly and the bottom end of the box frame are respectively provided with a first exhaust hole and a second exhaust hole facing each other, and the first exhaust hole and the second exhaust hole are communicated so that the pressure relief chamber is communicated with the pressure relief port.

[0018] As an optional solution to the above-mentioned battery box, at least one side wall of the box frame is hollow to form a buffer cavity, and the buffer cavity is connected to the pressure relief port and the pressure relief cavity;

[0019] A top partition plate and at least one bottom partition plate are arranged in the buffer cavity from top to bottom, and a through hole is arranged on the bottom partition plate.

[0020] A power battery comprises a battery cell and the above-mentioned battery box, wherein the battery cell is arranged in the cavity.

[0021] Beneficial effects of the present invention:

[0022] The base plate assembly provided by the present invention is provided with a heat exchange flow channel. The airflow generated after thermal runaway of the battery cell first enters the heat exchange flow channel through the connecting hole, exchanges heat with the heat exchange liquid in the heat exchange flow channel and cools down, and then is discharged through the pressure relief chamber. This can quickly reduce the temperature of the airflow generated during thermal runaway and avoid heat spread and safety accidents caused by it. The heat exchange inlet and heat exchange outlet of the heat exchange flow channel are both provided with waterproof and breathable membranes, which can allow airflow to pass through and prevent liquid flow to avoid the heat exchange liquid in the heat exchange flow channel from flowing out.

[0023] The battery box and power battery provided by the present invention adopt the above-mentioned bottom plate assembly, which can effectively control the temperature of the airflow during thermal runaway, avoid heat spread, and thus improve the safety level of the power battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 1 is a schematic structural diagram of a power battery provided in Embodiment 1 of the present invention;

[0025] Figure 2 This is a schematic structural diagram of the power battery provided by the first embodiment of the present invention when the box cover is not assembled;

[0026] Figure 3 This is a cross-sectional view of the power battery provided by the first embodiment of the present invention without an upper cold plate installed;

[0027] Figure 4 is a cross-sectional view of a floor assembly provided in Embodiment 1 of the present invention;

[0028] Figure 5 This is a structural diagram of the box frame and bottom guard plate provided in the first embodiment of the present invention;

[0029] Figure 6 This is a schematic structural diagram of the bottom guard plate provided in the first embodiment of the present invention;

[0030] Figure 7 yes Figure 3 A partial enlarged view of point A in the middle;

[0031] Figure 8 This is a structural diagram of the box frame and bottom guard plate provided in the first embodiment of the present invention;

[0032] Figure 9 is a cross-sectional view of a box frame provided in Example 1 of the present invention;

[0033] Figure 10 1 is a structural schematic diagram of a base plate assembly provided in Embodiment 1 of the present invention;

[0034] Figure 11 This is a schematic structural diagram of a power battery provided by the second embodiment of the present invention without a box cover installed;

[0035] Figure 121 is a structural diagram of a box frame and a bottom plate assembly provided in a second embodiment of the present invention;

[0036] Figure 13 This is a structural diagram of the box frame and bottom guard plate provided in the second embodiment of the present invention;

[0037] Figure 14 This is an exploded view of the power battery provided by the third embodiment of the present invention when the box cover is not assembled;

[0038] Figure 15 This is a cross-sectional view of the power battery provided by the third embodiment of the present invention when the box cover is not assembled.

[0039] In the picture:

[0040] 10. Battery case; 11. Case frame; 111. Buffer chamber; 112. Top partition; 113. Bottom partition; 1131. Through hole; 114. Second exhaust hole; 12. Bottom plate assembly; 120. Pressure relief chamber; 121. Bottom guard plate; 1210. Heat exchange flow channel; 1211. Protrusion; 1212. Heat exchange inlet; 1213. Heat exchange outlet; 1214. Waterproof breathable membrane; 122. Top plate; 1221. Flat plate; 12211. Top through hole; 1222. Flow channel plate; 12221. Bottom through hole; 1223. First exhaust hole; 12224. Diaphragm; 123. Heat exchange liquid; 13. Case cover; 20. Battery cell; 21. Main body; 22. Explosion-proof valve; 30. Pressure relief valve. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0042] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0043] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0044] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0045] Example 1

[0046] like Figure 1 and Figure 2 As shown, this embodiment provides a power battery, including a battery cell 20 and a battery case 10 . A cavity is formed in the battery case 10 , and a plurality of battery cells 20 are disposed in the cavity to form a modular structure.

[0047] The battery box 10 includes a box frame 11, a bottom plate assembly 12 and a box cover 13. The box frame 11 is a ring structure with open ends at the upper and lower ends; the bottom plate assembly 12 is connected to the bottom end of the box frame 11 to close the bottom end opening of the box frame 11, so that the bottom plate assembly 12 and the box frame 11 form a cavity for accommodating the battery cell 20; after the battery cell 20 is placed in the cavity, the box cover 13 is connected to the top end of the box frame 11 to close the top end opening of the box frame 11, thereby shielding the battery cell 20 and preventing the battery cell 20 from being exposed, thereby protecting the battery cell 20.

[0048] The battery cell 20 generates heat during operation. When the battery cell 20 experiences thermal runaway, the internal temperature of the battery cell 20 rises, generating high-pressure and high-temperature gas. To avoid explosions of the battery cell 20, Figure 3 As shown, the battery cell 20 includes a main body 21 and an explosion-proof valve 22. The explosion-proof valve 22 can open after the air pressure in the main body 21 increases to a certain value, so that the thermal runaway gas in the battery cell 20 can be discharged through the explosion-proof valve 22, thereby avoiding the situation where the air pressure in the battery cell 20 continues to increase and an explosion occurs.

[0049] In some embodiments, the battery cells 20 are blade cells. The length of the blade cells extends along the width of the battery case 10, and multiple blade cells are arranged in a row. The poles of the blade cells extend from both sides, and the explosion-proof valve 22 is located at the bottom of the main body 21, allowing current to be transmitted between the cells through the sides. If a cell experiences thermal runaway, the explosion-proof valve 22 opens, and the high-temperature, high-pressure thermal runaway gas is discharged from the bottom of the main body 21, achieving true thermal and electrical separation and improving overall safety.

[0050] To ensure that thermal runaway gases can be smoothly discharged from the battery case 10 and prevent heat spread, in some embodiments, a pressure relief vent is provided on the battery case 10. A pressure relief chamber 120 is formed within the battery case 10 and communicates with the pressure relief vent. The pressure relief chamber 120 can also communicate with the explosion-proof valve 22. When a battery cell 20 experiences thermal runaway and the explosion-proof valve 22 opens, the thermal runaway gases within the battery cell 20 enter the pressure relief chamber 120 through the explosion-proof valve 22 and are then discharged through the pressure relief vent. This prevents the thermal runaway gases from remaining in the battery case 10 for an extended period of time and potentially causing thermal runaway in other battery cells 20.

[0051] In some embodiments, the pressure relief port is provided on the box frame 11 to prevent the pressure relief port from being blocked by other external structures and to ensure that the thermal runaway gas is discharged smoothly.

[0052] To ensure the airtightness of the battery box 10 when the power battery is operating normally, in some embodiments, a pressure relief valve 30 is provided at the pressure relief port. The pressure relief valve 30 can open after the air pressure in the battery box 10 rises to a specified level to allow the thermal runaway gas to be discharged.

[0053] The pressure relief valve 30 serves as an explosion-proof ventilation device. When the battery cell 20 is not experiencing thermal runaway, the pressure relief valve 30 primarily serves as a ventilation device, regulating the pressure inside and outside the battery case 10. If thermal runaway occurs in the battery cell 20, the pressure relief valve 30 opens, allowing the gas inside the battery case 10 to be rapidly discharged, preventing accidents such as power battery explosion.

[0054] Optionally, the pressure relief valve 30 may be a needle-type pressure relief valve or a spring-type pressure relief valve.

[0055] In some embodiments, a pressure relief chamber 120 is formed within the base plate assembly 12. A communication hole corresponding to the explosion-proof valve 22 is provided on the top surface of the base plate assembly 12. The communication hole communicates with the pressure relief chamber 120, allowing gases generated by thermal runaway battery cells 20 to enter the pressure relief chamber 120 through the communication hole. Forming the pressure relief chamber 120 within the base plate assembly 12 separates the cavity housing the battery cells 20 from the pressure relief chamber 120, which is used to discharge thermal runaway gases. This reduces the residence time of gases generated by thermal runaway battery cells 20 within the cavity, helping to prevent heat spread.

[0056] In some embodiments, the bottom plate assembly 12 includes a bottom guard plate 121 and a top plate 122 that are stacked and connected. A pressure relief chamber 120 is formed between the bottom guard plate 121 and the top plate 122. A communication hole is provided on the top plate 122 to communicate with the explosion-proof valve 22. The pressure relief chamber 120 is formed by the bottom guard plate 121 and the top plate 122. Specifically, the circumferential edges of the bottom guard plate 121 and the top plate 122 are fixedly sealed to each other. The pressure relief chamber 120 can be provided within the entire large surface space of the top plate 122 and the bottom guard plate 121, thereby increasing the volume of the pressure relief chamber 120. At the same time, the structure is simple, easy to process, and easy to install, which helps to reduce costs.

[0057] In order to quickly suppress temperature transfer after the battery cell 20 thermal runaway, in some embodiments, Figure 3 and Figure 4 As shown, a heat exchange channel 1210 is also formed in the base plate assembly 12, and a heat exchange liquid 123 is contained in the heat exchange channel 1210. The heat exchange channel 1210 includes a heat exchange inlet 1212 and a heat exchange outlet 1213. The heat exchange inlet 1212 is connected to the connecting hole, and the heat exchange outlet 1213 is connected to the pressure relief chamber 120. The heat exchange inlet 1212 and the heat exchange outlet 1213 are both provided with a waterproof and breathable membrane 1214.

[0058] When a battery cell 20 experiences thermal runaway, the thermal runaway gas within the battery cell 20 first enters the heat exchange channel 1210 through the connecting hole and the heat exchange inlet 1212. The thermal runaway gas then contacts and exchanges heat with the heat exchange liquid 123 within the heat exchange channel 1210, rapidly reducing the temperature of the thermal runaway gas. The thermal runaway gas then enters the pressure relief chamber 120 through the heat exchange outlet 1213 and is discharged through the pressure relief port. This rapidly reduces the temperature of the airflow generated during thermal runaway, preventing heat from spreading and causing safety accidents. A waterproof, breathable membrane 1214 is provided at both the heat exchange inlet 1212 and the heat exchange outlet 1213 to prevent the heat exchange liquid 123 within the heat exchange channel 1210 from flowing out while ensuring smooth gas flow in and out.

[0059] In some embodiments, the waterproof and breathable membrane 1214 is a microporous membrane with a pore size between 0.1 μm and 10 μm. Since the molecular diameter of air is 0.00036 μm and the diameter of water mist (small water droplets) is about 500 μm, the pore size of the microporous membrane is larger than the molecular diameter of air, but much smaller than the molecular diameter of water mist. In addition, the surface energy of the microporous membrane is relatively low. Under the action of surface tension, small water droplets quickly form larger water droplets on the surface of the microporous membrane, further avoiding the entry and exit of water droplets, thereby achieving the effect that gas can pass through the microporous membrane smoothly, while liquid cannot pass through the microporous membrane, thereby achieving good waterproof and breathable performance.

[0060] It should be noted that the liquid level of the heat exchange liquid 123 in the heat exchange channel 1210 is lower than the height of the heat exchange channel 1210. In other words, the heat exchange channel 1210 is not completely filled with the heat exchange liquid 123, so that the thermal runaway gas can smoothly enter the heat exchange channel 1210. When the thermal runaway gas enters the heat exchange channel 1210, the air pressure in the heat exchange channel 1210 increases, allowing the thermal runaway gas to pass through the heat exchange liquid 123 for heat exchange. Furthermore, the exhaust rate and pressure of the thermal runaway gas are relatively high, so the thermal runaway gas will quickly pass through the heat exchange liquid 123 and be discharged through the heat exchange outlet 1213, thus preventing a sharp increase in the air pressure in the heat exchange channel 1210.

[0061] Optionally, the number of heat exchange outlets 1213 can be set to multiple, and the specific number is set according to actual needs to meet the need for rapid exhaust.

[0062] In some embodiments, the microporous membrane has a breaking pressure greater than 30 kPa. The exhaust pressure of the battery cell 20 during thermal runaway is approximately 6-20 kPa. For lithium-ion batteries, the exhaust pressure after thermal runaway is approximately 6-10 kPa, and for ternary batteries, the exhaust pressure is 12-20 kPa. These are both much lower than the breaking pressure of the microporous membrane, thus preventing thermal runaway gases from damaging the microporous membrane.

[0063] In some embodiments, the melting point of the microporous membrane is greater than 400° C., which is lower than the temperature of the thermal runaway gas, to avoid being destroyed.

[0064] Exemplarily, the waterproof breathable membrane 1214 is made of polytetrafluoroethylene, thermoplastic polyurethane elastomer, thermoplastic polyolefin, or ethylene-vinyl acetate copolymer. It should be noted that the above materials are merely examples, and the waterproof breathable membrane 1214 can be made of other materials as long as they can ensure the ingress and egress of thermal runaway gases while preventing the outflow of the heat exchange liquid 123.

[0065] By providing the heat exchange flow channel 1210 and the waterproof breathable membrane 1214, on the one hand, the temperature of the thermal runaway gas in the power battery can be quickly reduced, thereby reducing the overall temperature of the power battery. On the other hand, the temperature of the gas discharged from the outside of the power battery can be lowered, reducing the impact on the surrounding environment when thermal runaway occurs in the entire vehicle, and greatly improving the safety level of the power battery, the entire vehicle and the surrounding environment.

[0066] To improve space utilization, in some embodiments, the heat exchange channel 1210 is disposed within the pressure relief chamber 120. Utilizing the space within the pressure relief chamber 120 to dispose the heat exchange channel 1210 simplifies the flow path of the thermal runaway gas, thereby simplifying the structure and reducing costs. Furthermore, the heat exchange channel 1210 does not occupy additional space within the cavity, thereby improving space utilization.

[0067] In some embodiments, such as Figure 5As shown, the bottom guard plate 121 includes a protrusion 1211 protruding toward the top plate 122 , and a heat exchange channel 1210 is formed in the protrusion 1211 to facilitate molding the heat exchange channel 1210 in the pressure relief chamber 120 .

[0068] In some embodiments, the protrusion 1211 may be integrally formed with the bottom guard plate 121 , and the heat exchange channel 1210 may be formed in the protrusion 1211 by machining.

[0069] In some embodiments, the bottom guard plate 121 includes a first bottom plate and a second bottom plate stacked together, with the first bottom plate positioned above the second bottom plate. A portion of the first bottom plate is bent and convexed away from the second bottom plate to form a convex portion 1211, thereby forming a heat exchange channel 1210 between the first bottom plate and the second bottom plate. This method simplifies molding and facilitates processing, helping to reduce production costs.

[0070] In other embodiments, the convex portion 1211 may be a cover, which is buckled onto the bottom guard plate 121 and forms a heat exchange channel 1210 with the top surface of the bottom guard plate 121. Optionally, the cover and the bottom guard plate 121 may be welded or fixed and sealed by screws and seals.

[0071] In some embodiments, a heat exchange inlet 1212 is provided on the top surface of the protrusion 1211, and a heat exchange outlet 1213 is provided on the side of the protrusion 1211, which is conducive to the gas generated after the thermal runaway of the battery cell 20 above the bottom plate assembly 12 entering the heat exchange flow channel 1210 through the heat exchange inlet 1212; the direction in which the thermal runaway gas enters the heat exchange flow channel 1210 is different from the direction in which the thermal runaway gas flows out of the heat exchange flow channel 1210, which is conducive to the thermal runaway gas fully contacting with the heat exchange liquid 123 in the heat exchange flow channel 1210, so as to improve the cooling effect of the thermal runaway gas.

[0072] In some embodiments, the top surface of the convex portion 1211 abuts against the top plate 122, so that the convex portion 1211 divides the space in the pressure relief chamber 120 into two sub-pressure relief chambers. Figure 6 As shown, the two opposing longitudinal side surfaces of the protrusion 1211, respectively, enclose the bottom guard plate 121 and the top plate 122 to form a sub-pressure relief chamber. Each sub-pressure relief chamber is provided with a heat exchange outlet 1213 on the protrusion 1211, allowing the thermal runaway gas to be discharged in two opposing directions, thus diverting the gas flow and improving the heat dissipation efficiency of the thermal runaway gas. Furthermore, the abutment between the protrusion 1211 and the top plate 122 not only shortens the path for the thermal runaway gas to enter the heat exchange flow channel 1210, but also improves the strength of the bottom plate assembly 12, enabling it to withstand the impact of the thermal runaway gas, thereby preventing deformation of the bottom plate assembly 12 and improving the stability and reliability of the power battery.

[0073] In some embodiments, the protrusion 1211 is elongated and extends along the length of the bottom plate assembly 12. This can increase the size of the heat exchange channel 1210 formed within the protrusion 1211, thereby increasing the total amount of heat exchange liquid 123. This facilitates sufficient contact and heat exchange between the thermal runaway gas and the heat exchange liquid 123, thereby quickly controlling the temperature of the thermal runaway gas and preventing heat spread. Furthermore, it can increase the contact area between the protrusion 1211 and the top plate 122, thereby improving the strength of the bottom plate assembly 12. Furthermore, this configuration allows the protrusion 1211 to separate the pressure relief chamber 120 into two sub-pressure relief chambers, simplifying the exhaust path of the thermal runaway gas and improving the exhaust efficiency.

[0074] In other embodiments, the protrusion 1211 can be provided on the bottom surface of the top plate 122 and protrude toward the bottom guard plate 121, thereby also forming the heat exchange flow channel 1210. Optionally, the protrusion 1211 provided on the top plate 122 can abut against the bottom guard plate 121 to separate the pressure relief chamber 120 into two sub-pressure relief chambers, thereby achieving diversion and discharge of thermal runaway gases.

[0075] In some embodiments, the bottom plate assembly 12 and the box frame 11 can be fixed by welding, such as stir friction welding, or can be fixedly connected by bolts and sealed by a seal to reduce costs.

[0076] To reduce the probability of thermal runaway of the battery cells 20 , in some embodiments, the top plate 122 is a cold plate that contacts the battery cells 20 , thereby controlling the temperature of the battery cells 20 and preventing thermal runaway due to abnormal temperature of the battery cells 20 during operation.

[0077] In some embodiments, a cooling cavity is formed in the cold plate to circulate a cooling medium. The cooling medium absorbs and removes heat from the battery cells 20 , effectively controlling the temperature of the battery cells 20 and preventing thermal runaway of the battery cells 20 .

[0078] In some embodiments, the power battery further includes a medium inlet pipe and a medium outlet pipe, both of which are connected to the cooling cavity. The medium inlet pipe is used to introduce cooling medium into the cooling cavity, while the medium outlet pipe is used to discharge the cooling medium from the cooling cavity. The provision of the medium inlet pipe and the medium outlet pipe allows the cooling medium in the cooling cavity to circulate, which helps improve the cooling effect and thus enhances the temperature control of the battery cell 20.

[0079] Optionally, the medium inflow tube and the medium outflow tube may be nylon tubes.

[0080] In some embodiments, the power battery further includes a water pump, which can drive the cooling medium in the cold plate to circulate and cool the power battery.

[0081] In addition, since the cold plate encloses the pressure relief chamber 120, the cold plate can also exchange heat with the thermal runaway gas in the pressure relief chamber 120, which is beneficial to reducing the temperature of the thermal runaway gas and reducing the temperature of the gas discharged outside the battery box 10, thereby avoiding the temperature of the thermal runaway gas affecting other structures outside the battery box 10.

[0082] Combine Figure 4 and Figure 7 As shown, in some embodiments, the cold plate includes a flat plate 1221 and a flow channel plate 1222. The flat plate 1221 and the flow channel plate 1222 are stacked. The flow channel plate 1222 is provided with a groove. The groove and the flat plate 1221 form a cooling cavity. This structure forms a cooling cavity, is simple in structure, is easy to process, and helps reduce costs.

[0083] In some embodiments, the groove can be formed by stamping or other methods. On the one hand, the processing method is simple and the molding is convenient, which is conducive to reducing costs; on the other hand, it can increase the strength of the flow channel plate 1222 and improve the strength of the top plate 122, which is conducive to increasing the load-bearing capacity of the top plate 122 to support the battery cell 20.

[0084] It can be understood that the groove is formed by stamping, and the side of the flow channel plate 1222 facing the flat plate 1221 is concave inward. Correspondingly, the side of the flow channel plate 1222 facing away from the flat plate 1221 forms a first ridge protruding outward, so as to ensure that the groove has a certain depth without increasing the thickness of the flow channel plate 1222, thereby ensuring the amount of cooling medium in the cooling cavity and ensuring the heat exchange effect.

[0085] In some embodiments, the groove can be a curved extension, or include cross-arranged transverse grooves and longitudinal grooves, so as to increase the total length of the groove on the basis of keeping the size of the flow channel plate 1222 unchanged, which is beneficial to increase the volume of the cooling cavity, thereby increasing the total amount of cooling medium and improving the heat exchange effect.

[0086] Optionally, the cold plate can be made of 3003 aluminum alloy. After the flow channel plate 1222 is stamped and formed, the flat plate 1221 and the flow channel plate 1222 are fixed by integral brazing to ensure structural strength and sealing.

[0087] In some embodiments, such as Figure 4 、 Figure 7-Figure 8 As shown, the connecting holes include a top through hole 12211 located on the flat plate 1221 and a bottom through hole 12221 located on the flow channel plate 1222. After the explosion-proof valve 22 is opened, the thermal runaway gas passes through the top through hole 12211, the bottom through hole 12221 and the heat exchange inlet 1212 in sequence and enters the heat exchange flow channel 1210.

[0088] Since a first ridge is formed on the side of the flow channel plate 1222 facing away from the flat plate 1221 at a position corresponding to the groove, the convex portion 1211 abuts against the first ridge, resulting in a certain distance between the position of the flow channel plate 1222 where the first ridge is not set and the convex portion 1211. If the bottom through hole 12221 is directly set at this position, there will be a certain distance between the bottom through hole 12221 and the convex portion 1211, and some of the thermal runaway gas will overflow through the bottom through hole 12221, and it cannot be guaranteed that all the thermal runaway gas will enter the heat exchange flow channel 1210.

[0089] To address this issue, the side of the flow channel plate 1222 facing the flat plate 1221 is recessed at a location corresponding to the top through hole 12211 to form a buffer groove. Correspondingly, a second ridge is formed on the side of the flow channel plate 1222 facing the protrusion 1211. The second ridge abuts against the protrusion 1211, and the bottom through hole 12221 is positioned on the second ridge. This arrangement reduces the height difference between the bottom through hole 12221 and the heat exchange inlet 1212, reducing the outflow of thermal runaway gases and ensuring that all thermal runaway gases passing through the bottom through hole 12221 can enter the heat exchange flow channel 1210 through the heat exchange inlet 1212, thereby improving the directional drainage and cooling effect of the thermal runaway gases.

[0090] In addition, the cross-sectional area of ​​the top through hole 12211 is larger than that of the bottom through hole 12221, and the cross-sectional area of ​​the buffer tank gradually decreases from the top through hole 12211 to the bottom through hole 12221, so that the thermal runaway gas can quickly enter the top through hole 12211, and the thermal runaway airflow entering through the top through hole 12211 can enter the buffer tank, be buffered by contact with the inner wall of the buffer tank, and then enter the heat exchange flow channel 1210 through the bottom through hole 12221 and the heat exchange inlet 1212, reducing the impact of the thermal runaway gas on the heat exchange flow channel 1210, so as to avoid deformation of the protrusion 1211 and the bottom guard plate 121.

[0091] It should be noted here that the buffer tank is not connected to the groove to prevent the cooling medium in the cooling cavity from entering the buffer tank.

[0092] In some embodiments, the depth of the buffer groove and the groove can be the same to facilitate production and processing and reduce costs. The specific depth can be selected according to actual needs.

[0093] In some embodiments, a diaphragm 12224 is provided at the communication hole. The diaphragm 12224 is configured to allow thermal runaway gas from the battery cell to leak out of the communication hole, while also sealing the communication hole when the battery cell is operating normally. The provision of the diaphragm 12224 allows the communication hole to be sealed during normal operation of the power battery, disconnecting the cavity from the pressure relief chamber 120. This helps maintain internal sealing and prevents debris or other components from falling through the communication hole into the pressure relief chamber 120 during assembly. When a battery cell 20 experiences thermal runaway, high-pressure, high-temperature thermal runaway gas is ejected from the explosion-proof valve 22. The hot air acts on the diaphragm 12224, causing the communication hole to leak out, connecting the cavity to the pressure relief chamber 120 and facilitating the discharge of the thermal runaway gas.

[0094] In some embodiments, the diaphragm 12224 can be made of a material with a low melting point and good sealing properties, so that the diaphragm 12224 can seal the connecting hole when the battery cell 20 does not experience thermal runaway, and the diaphragm 12224 can melt under the action of high temperature and high pressure thermal runaway gas, thereby exposing the connecting hole.

[0095] In one embodiment, the diaphragm 12224 can be tin foil.

[0096] In one embodiment, the diaphragm 12224 can be an aluminum-plastic film. This is an aluminum-plastic composite film composed of an outer nylon layer, a middle aluminum foil layer, and an inner heat-seal layer. The outer nylon layer protects the middle aluminum foil layer from scratches; the middle aluminum foil layer prevents moisture from entering or exiting; and the inner heat-seal layer provides a seal.

[0097] Among them, the inner heat-sealing layer can be made of CPP (cast polypropylene film) or PP (polypropylene) to have a better sealing effect.

[0098] Optionally, the outer nylon layer and the middle aluminum foil layer, and the middle aluminum foil layer and the inner heat-sealing layer are bonded and pressed together with an adhesive to improve the fixing effect between the layers.

[0099] In some embodiments, the thickness of the diaphragm 12224 may be 80 μm to 150 μm. Typical non-limiting values ​​for the thickness of the diaphragm 12224 may be 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, 125 μm, 130 μm, 135 μm, 140 μm, 145 μm, or 150 μm.

[0100] In some embodiments, a layer of diaphragm 12224 can be provided at each connecting hole, and the diaphragm 12224 can be provided on the outside of the flow channel plate 1222 or on the inside of the flat plate 1221; in some other embodiments, the diaphragm 12224 can be provided in two layers, for example, a layer of diaphragm 12224 is provided on the inside of the flat plate 1221 and the outside of the flow channel plate 1222, or a layer of diaphragm 12224 is provided on the inside and outside of the flat plate 1221, or a layer of diaphragm 12224 is provided on the inside and outside of the flow channel plate 1222, for double protection. The diaphragm 12224 can also be provided in three or four layers, which can be set as needed.

[0101] It should be noted here that the diaphragm 12224 has a low melting point and a thin thickness. When thermal runaway occurs in the battery cell 20, the diaphragm 12224 will melt quickly to open the connecting hole; even if some of the diaphragm 12224 remains, the residual amount is small and will not affect the inflow and outflow of gas at the connecting hole and the heat exchange inlet 1212.

[0102] like Figure 9 As shown, at least one side wall of the box frame 11 is hollow to form a buffer chamber 111, which connects the pressure relief port and the pressure relief chamber 120. When the battery cell 20 experiences thermal runaway, the thermal runaway gas flows through the heat exchange channel 1210 and the pressure relief chamber 120 in sequence, enters the buffer chamber 111, and is finally discharged through the pressure relief valve 30. The thermal runaway gas is ultimately discharged through the box frame 11, which ensures that the pressure relief port is not blocked and extends the flow path of the thermal runaway gas, which helps to reduce the temperature of the thermal runaway gas after discharge and prevent the thermal runaway gas from being too high and affecting other external structures.

[0103] In order to improve the buffering effect of the thermal runaway gas in the buffer chamber 111, in some embodiments, a top partition 112 and at least one bottom partition 113 are provided in the buffer chamber 111 from top to bottom. The top partition 112 and at least one bottom partition 113 divide the buffer chamber 111 into multiple sub-buffer chambers, and the bottom partition 113 is provided with a through hole 1131. In other words, the through hole 1131 on the bottom partition 113 can connect two adjacent sub-buffer chambers, so that the thermal runaway gas can flow and disperse in the multiple sub-buffer chambers to achieve a buffering effect; the top partition 112 has no holes, which can prevent the thermal runaway gas from passing over the top partition 112 and continuing to move upward, thereby preventing the temperature of the thermal runaway gas from affecting other structures on the top of the box frame 11, such as preventing the heat from affecting the failure of the seal between the box cover 13 and the box frame 11.

[0104] In some embodiments, the pressure relief port is connected to the sub-buffer cavity below the top partition 112, so that the thermal runaway gas can be blocked and buffered by at least one bottom partition 113, enter the sub-buffer cavity below the top partition 112, and be discharged through the pressure relief port, which is beneficial to improving the buffering effect and reducing the final discharge temperature of the thermal runaway gas.

[0105] In some embodiments, the through holes on the bottom baffle 113 are staggered, which helps to extend the flow path of the thermal runaway gas to improve the buffering and cooling effects.

[0106] like Figure 9 As shown, exemplarily, there are three bottom partitions 113, and the top partition 112 and the three bottom partitions 113 divide the buffer chamber 111 into five sub-buffer chambers. The top sub-buffer chamber is not connected to the other four sub-buffer chambers, and the four sub-buffer chambers below are connected. The pressure relief port is connected to the second sub-buffer chamber from top to bottom.

[0107] The box frame 11 and the bottom plate assembly 12 also enclose an electrical compartment, located to one side of the cavity, for housing structures such as the battery management system. To prevent thermal runaway gases from affecting the structural components within the electrical compartment, in some embodiments, a buffer cavity 111 is provided circumferentially around the cavity. A sealing plate is provided at the end of the buffer cavity 111 facing the electrical compartment. The sealing plate is welded to the box frame 11 and sealed. The sealing plate is used to prevent thermal runaway gases from migrating toward the electrical compartment, thereby preventing heat from affecting components within the compartment.

[0108] In some embodiments, the electrical chamber is located at the front side of the cavity, the buffer cavity 111 is roughly U-shaped, and two sealing plates are provided. Sealing plates are provided at the front end of both side walls of the U-shaped buffer cavity 111 to prevent thermal runaway gas from flowing to the front end of the box frame 11.

[0109] In order to make the pressure relief chamber 120 communicate with the buffer chamber 111, in some embodiments, Figure 4 and Figure 10 As shown, the connecting surfaces of the bottom ends of the bottom plate assembly 12 and the box frame 11 are respectively provided with a first exhaust hole 1223 and a second exhaust hole 114 opposite to each other, and the first exhaust hole 1223 and the second exhaust hole 114 are connected so that the pressure relief chamber 120 is connected with the pressure relief port.

[0110] Optionally, first exhaust holes 1223 are provided on the top plate 122, so that thermal runaway gases entering the pressure relief chamber 120 can pass through the first exhaust holes 1223 on the top plate 122 and enter the second exhaust holes 114 at the bottom end of the box frame 11. In this embodiment, the first exhaust holes 1223 are provided on both sides of the top plate 122 in the longitudinal direction to correspond to the two sub-pressure relief chambers, and the first exhaust holes 1223 can be spaced apart along the length of the top plate 122, thereby facilitating the diversion and rapid discharge of thermal runaway gases.

[0111] It can be understood that the apertures of the first exhaust hole 1223 and the second exhaust hole 114 are relatively small, and the flow rate of the thermal runaway gas increases when passing through the first exhaust hole 1223 and the second exhaust hole 114, and the heat exchange efficiency increases, so that the temperature of the gas is significantly reduced after flowing through the exhaust holes.

[0112] In some embodiments, the case cover 13 may be a cold plate with a cooling medium flowing through it. The case cover 13 serves as the upper cover of the battery case 10, improving structural strength and sealing, making it suitable for CTB (cell to body) or CTC (cell to chassis) solutions and enhancing overall integration. It can also function as a cooling component. Cold plates are placed on the top and bottom of the battery cells 20, allowing both the top and bottom surfaces of the battery cells 20 to be cooled, thereby increasing heat exchange efficiency.

[0113] The specific structure and material of the box cover 13 can refer to the structure and material of the top plate 122 mentioned above, and will not be described in detail here.

[0114] In some embodiments, a thermally conductive structural adhesive layer is provided between the box cover 13 and the battery cell 20, and between the battery cell 20 and the bottom plate assembly 12. The thermally conductive structural adhesive layer serves as a filling medium between the box cover 13 and the battery cell 20, and between the bottom plate assembly 12 and the battery cell 20. On the basis of providing good thermal conductivity, it also improves the overall structural strength, so that the battery cell 20, the box cover 13 and the bottom plate assembly 12 become a whole, thereby improving the overall modality.

[0115] In some embodiments, the box frame 11 is formed by connecting profiles by means of friction stir welding, arc welding, or laser welding to improve structural strength.

[0116] Optionally, pressure relief ports are provided on opposite sides of the box frame 11 , the number of which is set according to actual needs, and each pressure relief port is provided with a pressure relief valve 30 .

[0117] After thermal runaway occurs in a cell 20 of the power battery, the thermal runaway gas is ejected from the explosion-proof valve 22 at the bottom of the main body 21. It then passes through the connecting hole, heat exchange inlet 1212, heat exchange channel 1210, heat exchange outlet 1213, pressure relief chamber 120, and buffer chamber 111, before being discharged through the pressure relief port, achieving directional exhaust. The thermal runaway gas is rapidly cooled by the cold plate and heat exchange channel 1210, preventing damage to surrounding components and the vehicle's surrounding environment. When thermal runaway occurs, the battery management system detects a thermal runaway signal and quickly switches the vehicle's power source, avoiding problems like high-voltage short circuits and improving safety. When the vehicle's power is cut off, a lower voltage power source (e.g., 12V) is used to drive the water pump, allowing the coolant to circulate, allowing the cold plate to cool the power battery, significantly improving safety.

[0118] Example 2

[0119] This embodiment provides a power battery, which has a structure substantially the same as that of the power battery in the first embodiment, except that: Figure 11 As shown, the battery cell 20 is a square shell battery cell, which is arranged in multiple rows. An explosion-proof valve 22 is provided at the bottom of each square shell battery cell, and the pole is located at the top of the battery cell, thereby achieving thermal and electrical separation. Figure 12 As shown, multiple rows of connecting holes are provided, so that the top plate 122 is provided with a top through hole 12211 and a bottom through hole 12221 corresponding to each square shell battery cell, so that the thermal runaway gas generated by each square shell battery cell after thermal runaway can enter the pressure relief chamber 120 through the connecting holes.

[0120] In some embodiments, the square shell battery cell can adopt a bottom cooling solution, that is, the top plate 122 of the bottom plate assembly 12 is a cold plate, and the square shell battery cell is cooled by contacting the bottom of the square shell battery cell.

[0121] In other possible implementations, the square shell battery cell can add top cooling, side cooling or large surface cooling according to actual needs. Top cooling refers to adding a cold plate on the top of the square shell battery cell, for example, the box cover 13 is a cold plate; side cooling refers to adding a cold plate on the side of the square shell battery cell in the width direction; large surface cooling refers to adding a cold plate on the side of the square shell battery cell in the length direction.

[0122] In some embodiments, such as Figure 13 As shown, the convex portion 1211 is provided with a heat exchange inlet 1212 corresponding to each prismatic battery cell on the convex portion 1211, so as to communicate with the corresponding prismatic battery cell through the connecting hole. In other words, the top surface of the convex portion 1211 is provided with multiple rows of heat exchange inlets 1212, and the side surface of the convex portion 1211 is provided with heat exchange outlets 1213.

[0123] In some other embodiments, multiple protrusions 1211 are provided, each protrusion 1211 corresponding to a row of prismatic battery cells, and a plurality of heat exchange inlets 1212 are provided on the top surface of the protrusion 1211 facing the row of prismatic battery cells. The length of each protrusion 1211 is less than the length of the bottom guard plate 121, so that the spaces between two adjacent protrusions 1211 can be interconnected, facilitating the discharge of thermal runaway gases.

[0124] Example 3

[0125] This embodiment provides a power battery, which has a structure substantially the same as that of the power battery in the first embodiment, except that: Figure 14 and Figure 15 As shown, the battery cell 20 is a cylindrical battery cell, and multiple cylindrical battery cells are arranged in multiple rows. A communication hole is provided on the top plate 122 corresponding to each cylindrical battery cell, and a diaphragm 12224 is provided in the communication hole.

[0126] In some embodiments, the top plate 122 may be a flat plate structure and is no longer configured as a cold plate. Correspondingly, a serpentine cold plate is provided between two adjacent rows of cylindrical battery cells, and the serpentine cold plate is bent to fit the cylindrical surfaces of adjacent cylindrical battery cells respectively.

[0127] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A base plate assembly for supporting a battery cell (20), wherein the bottom end of the battery cell (20) is provided with an explosion-proof valve (22), characterized in that: The bottom plate assembly comprises a bottom guard plate (121) and a top plate (122) which are stacked and connected. A pressure relief chamber (120) is formed between the bottom guard plate (121) and the top plate (122). A heat exchange channel (1210) is provided in the pressure relief chamber (120). A communication hole corresponding to the explosion-proof valve (22) is provided on the top plate (122). A heat exchange liquid is contained in the heat exchange channel (1210). The heat exchange channel (1210) comprises a heat exchange inlet (1212) and a heat exchange outlet (1213). The heat exchange inlet (1212) is in communication with the communication hole, and the heat exchange outlet (1213) is in communication with the pressure relief chamber (120). Both the heat exchange inlet (1212) and the heat exchange outlet (1213) are provided with a waterproof and breathable membrane (1214). The bottom guard plate (121) comprises a convex portion (1211) protruding toward the top plate (122) and extending along the length direction of the bottom plate assembly; the top surface of the convex portion (1211) abuts against the top plate (122); two side surfaces of the convex portion (1211) in the opposite length direction respectively enclose the bottom guard plate (121) and the top plate (122) to form two sub-pressure relief chambers; the heat exchange flow channel (1210) is formed in the convex portion (1211); the heat exchange inlet (1212) is provided on the top surface of the convex portion (1211); and the heat exchange outlet (1213) is provided on the side surface of the convex portion (1211) corresponding to each of the sub-pressure relief chambers.

2. The floor assembly according to claim 1, characterized in that: The waterproof and breathable membrane (1214) is made of polytetrafluoroethylene, thermoplastic polyurethane elastomer, thermoplastic polyolefin or ethylene-vinyl acetate copolymer.

3. The floor assembly according to claim 1, characterized in that: The top plate (122) is a cold plate, a cooling cavity is formed in the cold plate, and the cooling cavity is used for circulating a cooling medium.

4. The floor assembly according to any one of claims 1 to 3, characterized in that: A diaphragm (12224) is provided at the communication hole, and the diaphragm (12224) is configured to be able to leak out of the communication hole under the action of thermal runaway gas of the battery cell (20), and to be able to seal the communication hole when the battery cell (20) is in a normal state.

5. A battery box, characterized in that: include: A box frame (11), wherein the box frame (11) is provided with a pressure relief port; The floor assembly according to any one of claims 1 to 4, wherein the floor assembly is connected to the bottom end of the box frame (11) and encloses a cavity for accommodating a battery cell (20); The connecting surfaces of the bottom end of the bottom plate assembly and the box frame (11) are respectively provided with a first exhaust hole (1223) and a second exhaust hole (114) facing each other, and the first exhaust hole (1223) and the second exhaust hole (114) are connected so that the pressure relief chamber (120) is connected to the pressure relief port.

6. The battery box according to claim 5, characterized in that: At least one side wall of the box frame (11) is hollow to form a buffer cavity (111), and the buffer cavity (111) is connected to the pressure relief port and the pressure relief cavity (120); A top partition plate (112) and at least one bottom partition plate (113) are provided in the buffer cavity (111) from top to bottom, and a through hole (1131) is provided on the bottom partition plate (113).

7. A power battery, characterized in that: The invention comprises a battery cell (20) and a battery box according to claim 5 or 6, wherein the battery cell (20) is arranged in the cavity.

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