Thermal safety protection system and battery pack

Abstract

This application provides a thermal safety protection system and a battery pack. The thermal safety protection system includes: a first side plate located on the side of the battery cell where an explosion-proof valve is located, the first side plate having a drain portion opposite to the explosion-proof valve; a second side plate connected to one end of the first side plate; and a third side plate connected to the other end of the second side plate, the third side plate and the second side plate being located on opposite sides of the battery cell along a first direction. This thermal safety protection system is used to improve the safety of the battery pack.

Description

Technical Field

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

[0002] With the development of science and technology and the continuous increase in energy demand, new energy storage devices have become a hot topic in the field of new energy. Battery packs are widely used in information technology, electric vehicles, aerospace and other fields. As the energy density of battery packs increases, their safety becomes increasingly important.

[0003] When energy is released abnormally within a battery pack, thermal runaway occurs. During thermal runaway, the individual battery cells inside the pack experience a dramatic temperature rise, ejecting high-velocity, high-temperature, high-pressure jets that can easily melt the aluminum casing surrounding the cell's explosion-proof valve. Furthermore, the jet direction is unpredictable; when a lateral jet forms, it can impact and ablate surrounding cells and their explosion-proof valves, causing them to also experience thermal runaway. This thermal runaway propagates throughout the battery pack, leading to fires, explosions, and other safety accidents, seriously threatening people's lives and causing property damage.

[0004] The battery pack has poor protection against thermal runaway, resulting in low safety. Utility Model Content

[0005] This application provides a thermal safety protection system and a battery pack to achieve the effect of providing battery pack safety.

[0006] In a first aspect, embodiments of this application provide a thermal safety protection system, which is installed over a battery cell, the battery cell having an explosion-proof valve, the thermal safety protection system comprising:

[0007] The first side plate is located on the side of the battery cell where the explosion-proof valve is located. The first side plate has a drainage part, which is opposite to the explosion-proof valve.

[0008] The second side plate is connected to one end of the first side plate;

[0009] The third side plate is connected to the other end of the second side plate, and the third side plate and the second side plate are respectively located on opposite sides of the battery cell along the first direction.

[0010] In some embodiments, the first side plate includes: a first insulating layer, a first heat insulation layer, and a first encapsulation layer stacked sequentially along a direction away from the battery cell;

[0011] The first insulating layer has a first window, which is opposite to the explosion-proof valve;

[0012] The first encapsulation layer has a second window, which is opposite to the first window;

[0013] The first thermal insulation layer exposed within the first window and the second window ruptures during thermal runaway of the battery cell, and the first window, the second window, and the first thermal insulation layer exposed within the first window and the second window form the drainage portion.

[0014] In some embodiments, the first insulating layer is an organic solvent coating;

[0015] And / or, the first insulation layer is an organic fiber layer;

[0016] And / or, the first encapsulation layer is an aqueous spray resin material layer or a polycarbonate layer.

[0017] In some embodiments, the second side plate includes: a second insulating layer, a second heat insulation layer, and a second encapsulation layer stacked sequentially along the direction away from the battery cell;

[0018] The third side plate includes a third insulating layer, a third heat insulation layer, and a third encapsulation layer stacked sequentially along the direction away from the battery cell.

[0019] In some embodiments, the first insulating layer, the second insulating layer, and the third insulating layer are an integral structure;

[0020] And / or, the first encapsulation layer, the second encapsulation layer, and the third encapsulation layer are an integral structure;

[0021] And / or, the first heat insulation layer, the second heat insulation layer and the third heat insulation layer are an integral structure.

[0022] In some embodiments, the thermal safety protection system further includes:

[0023] The fourth side plate connects the second side plate and the third side plate and is opposite to the first side plate. The thermal safety protection system is sleeved on the outside of the battery cell.

[0024] In some embodiments, the battery cell has multiple cells, and each battery cell is provided with a corresponding thermal safety protection system;

[0025] Alternatively, at least two adjacent battery cells may be provided with a corresponding thermal safety protection system, the drain section of which corresponds to the explosion-proof valve.

[0026] In some embodiments, the first direction is parallel to the thickness direction of the battery cell;

[0027] The explosion-proof valve is disposed on one of the two opposite sides of the battery cell along its width direction;

[0028] The battery cell also has tabs, which are disposed on at least one of the opposite sides of the battery cell along its length.

[0029] This application embodiment also provides a battery pack, including:

[0030] Battery box;

[0031] At least one battery cell is disposed in the battery box, and each battery cell has an explosion-proof valve;

[0032] The thermal safety protection system described above is installed inside the battery box, and the thermal safety protection system covers at least one of the battery cells.

[0033] In some embodiments, the battery cell has at least two cells, and the battery pack further includes a connecting tab disposed within the battery housing and connecting adjacent battery cells; and / or,

[0034] The battery box includes a box body and a box cover connected to the box body; and / or,

[0035] The battery pack further includes a circuit board and a battery pack circuit breaker unit, which are disposed inside the battery box. The battery pack circuit breaker unit is connected to the battery cell, and the circuit board is connected to both the battery cell and the battery pack circuit breaker unit.

[0036] The thermal safety protection system and battery pack provided in this application embodiment include a first side plate, a second side plate, and a third side plate. The first side plate is located on the side of the battery cell where the explosion-proof valve is located, and the first side plate has a drain portion opposite to the explosion-proof valve. The second side plate is connected to one end of the first side plate, and the third side plate is connected to the other end of the second side plate. The third side plate and the second side plate are located on opposite sides of the battery cell along a first direction. The second and third side plates isolate the battery cell, and the drain portion on the first side plate provides a jet channel in case of thermal runaway, allowing the jet to be ejected along the drain portion, thereby controlling the jet direction, avoiding lateral jetting, reducing thermal runaway propagation, and improving the safety of the battery pack. Attached Figure Description

[0037] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0038] Figure 1 A schematic diagram of a battery pack provided in this application;

[0039] Figure 2 Another structural schematic diagram of the battery pack provided in this application;

[0040] Figure 3 This is a schematic diagram of the thermal safety protection system provided in this application;

[0041] Figure 4 An explosion diagram of the thermal safety protection system provided in this application;

[0042] Figure 5 A schematic diagram of the stacked structure provided in this application;

[0043] Figure 6 An exploded view of the stacked structure provided in this application.

[0044] Explanation of reference numerals in the attached figures:

[0045] 11-Box body; 12-Box cover; 13-Crossbeam; 14-Longitudinal beam; 15-Partition;

[0046] 21-Battery cell; 22-Electrical tab; 23-Battery pack circuit breaker unit; 24-Circuit board;

[0047] 31-First side plate; 32-First insulating layer; 33-First heat insulation layer; 34-First encapsulation layer; 35-First window; 36-Drainage part; 37-Hole;

[0048] 41-Second side panel; 42-Second insulating layer; 43-Second heat insulation layer; 44-Second encapsulation layer;

[0049] 51-Third side panel; 52-Third insulation layer; 53-Third heat insulation layer; 54-Third encapsulation layer; 55-Second window;

[0050] 60 - Layered structure; 61 - Insulating layer; 62 - Thermal insulation layer; 63 - Encapsulation layer;

[0051] 70 - Thermal safety protection system. Detailed Implementation

[0052] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0053] When a battery pack experiences thermal runaway, various materials within the individual cells undergo successive thermochemical reactions, resulting in the ejection of high-velocity, high-temperature, and high-pressure jets. This is particularly true for lithium-ion cells, high-nickel ternary cells, and lithium iron manganese cells, whose ejected jets are essentially molten liquids. The direction of these ejected jets is unpredictable and can cause severe damage to surrounding cells and explosion-proof valves. In related technologies, controlling the jets generated after a battery pack experiences thermal runaway is difficult; that is, it is challenging to effectively manage the jets generated after a battery pack experiences thermal runaway.

[0054] Therefore, embodiments of this application provide a thermal safety protection system and battery pack. The system utilizes a second and third side plate to isolate the battery cell from other structures (e.g., other battery cells), and uses a drain portion on the first side plate to provide a jet channel in case of thermal runaway. This allows the jet to exit along the drain portion, thereby controlling the jet direction, preventing lateral jetting, reducing thermal runaway propagation, and improving the safety of the battery pack.

[0055] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0056] This application provides an electrical device, which can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, electric boats, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc. Electric vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc.

[0057] The aforementioned electrical equipment includes a battery pack for storing and providing electrical energy. For example, an electric vehicle may have a battery pack internally located, which may be situated at the bottom, front, or rear of the vehicle. The battery pack can be used to power the electric vehicle; for instance, it can serve as the operating power source. The electric vehicle may also include a controller and a motor. The controller controls the battery pack to supply power to the motor, for example, to meet the power requirements during starting, navigation, and driving. In some embodiments of this application, the battery pack can not only serve as the operating power source for the electric vehicle but also as its drive power source, replacing or partially replacing fuel or natural gas to provide driving power.

[0058] Among these, battery packs include, for example, lithium-ion battery packs, which have high specific energy of individual cells and low internal resistance, resulting in good driving range. Other examples of battery packs include high-nickel ternary lithium battery packs and lithium iron manganese battery packs. These battery packs can be liquid, semi-solid, or solid-state battery packs, depending on the form of the electrolyte within the pack.

[0059] See Figures 1 to 6 The battery pack may include a battery box and at least one battery cell 21 disposed within the battery box, each battery cell 21 having an explosion-proof valve. The battery box provides support and protection for the battery cells 21, etc., and the battery box may form a closed structure to meet requirements such as waterproofing and dustproofing. Figure 2 and Figure 3 As shown, in some possible examples, the battery box includes a box body 11 and a cover 12 connected to the box body 11. The box body 11 has an opening, and the cover 12 is fastened onto the opening to close it. The box body 11 and the cover 12 form a receiving space for accommodating the battery cell 21. The box body 11 and the cover 12 can be connected by structural adhesive or by fasteners. The box body 11 and the cover 12 are made of at least one of metal, plastic, ceramic, and composite materials. Composite materials include carbon fiber composites, glass fiber reinforced composites, sheet molding compounds (SMC), etc.

[0060] The enclosure 11 includes a base plate and a frame. The frame is located on one side of the base plate and connected to it; for example, the frame and base plate are an integral structure. The base plate and frame enclose at least a partial receiving space. An opening is formed on the side of the base plate facing away from the frame, and a cover 12 is correspondingly located on the frame. The frame includes, for example, a first end beam, a second end beam, a third end beam, and a fourth end beam connected in sequence. The first end beam and the third end beam are opposite each other, and the second end beam and the fourth end beam are opposite each other.

[0061] In some possible examples, the battery box also includes crossbeams 13 and longitudinal beams 14 disposed within the box body 11 to position and fix the battery cells 21. The extension directions of the crossbeams 13 and longitudinal beams 14 intersect, for example, perpendicularly. Specifically, the extension direction of the crossbeams 13 may be parallel to the width direction of the box body 11, and the longitudinal beams 14 may be parallel to the length direction of the box body 11. The width direction of the box body 11 is the width direction of the battery box, and the length direction of the box body 11 is the length direction of the battery box. The crossbeams 13 and longitudinal beams 14 may be connected to the bottom wall of the box body 11, for example, by structural adhesive, welding, or fasteners; or, for example, the crossbeams 13, longitudinal beams 14, and box body 11 may be an integral structure.

[0062] In some possible examples, the battery box also includes partitions 15 disposed within the housing 11, with the partitions 15 positioned beside the battery cells 21. For example, there may be two partitions 15, each positioned on one side of the battery cell 21, and the crossbeam 13 and longitudinal beam 14 may be located between the two partitions 15. By providing the partitions 15, the battery cells 21 can be separated from other structures. The two ends of the partitions 15 are connected to opposite side walls of the housing 11. That is, one end of the partition 15 is connected to one side wall of the housing 11, and the other end of the partition 15 is connected to the other side wall of the housing 11. These two side walls are positioned opposite each other, for example, along the width direction of the housing 11.

[0063] See Figure 1 and Figure 2The battery pack may include multiple battery cells 21 to improve the voltage, capacity, etc., of the battery pack and meet different power demands. These battery cells 21 can be integrated into battery modules and then formed into a battery pack, i.e., a CTM (Cell to Module) battery pack; these battery cells 21 can also be directly integrated into a battery pack, i.e., a CTP (Cell to Pack) battery pack. The battery cells 21 can be cylindrical or rectangular. In this embodiment, the shape of the battery cells 21 and the connection method (series, parallel, or mixed) between the battery cells 21 are not limited.

[0064] In some possible examples, multiple battery cells 21 are arranged in an array, for example, along the length of the battery box and along the width of the battery box. The length of the battery box may be parallel to the thickness of the battery cells 21, the width of the battery box may be parallel to the length of the battery cells 21, and the height of the battery box may be parallel to the width of the battery cells 21. The multiple battery cells 21 may form at least two battery modules, for example, at least two large modules, and the battery modules may be fixed and separated by crossbeams 13 and longitudinal beams 14.

[0065] The battery cell 21 has an explosion-proof valve, which is used to release pressure when the internal pressure of the battery cell 21 is too high, to prevent the battery cell 21 from exploding or catching fire. The explosion-proof valve is located on one side of the battery cell 21, on one of the opposite sides along its width direction, such as... Figure 1 and Figure 2 As shown, the explosion-proof valve is located on the top of the battery cell 21 to ensure that the battery pack ejects air upwards as much as possible in the event of a battery pack failure. The battery cell 21 also has tabs 22, which are located on opposite sides of the explosion-proof valve, i.e., the tabs 22 and the explosion-proof valve are located on different sides of the battery cell 21. The tabs 22 are located on at least one of the opposite sides of the battery cell 21 along its length, and the tabs 22 are opposite to the side wall of the housing 11, i.e., the battery cell 21 is a side-mounted tab cell 21. Exemplarily, the tabs 22 of the battery cell 21 include a positive tab and a negative tab, which are located on opposite sides of the battery cell 21, respectively.

[0066] The cell 21 is also filled with an electrolyte, which is used to charge and discharge the cell 21. The type of electrolyte is related to the type of cell 21. For example, the electrolyte in a lithium-ion battery is a mixture of an organic solvent (such as ethylene carbonate, dimethyl carbonate, etc.) and a lithium salt (such as lithium hexafluorophosphate, etc.). The cell 21 also has a casing to contain the electrolyte, etc. Electrodes, separators, etc. are also disposed inside the cell 21. The cell 21 can adopt an existing structure, which will not be described in detail here.

[0067] In some possible examples, there are at least two cells 21, and the battery pack also includes connecting tabs disposed within the battery casing and connecting adjacent cells 21. The connecting tabs enable series, parallel, or mixed connection between at least two cells 21, achieving electrical connection between the cells 21, allowing several cells 21 to be assembled into a battery module, which is then placed inside the battery casing to form a battery pack. The connecting tabs are welded or bonded to the corresponding cells 21; the connecting tabs are, for example, copper or aluminum busbars. Using aluminum busbars for the connectors reduces cost and weight compared to copper busbars.

[0068] To enable electrical connection between the battery pack and external components and to manage the battery pack, the battery pack also includes a circuit board 24 and a battery distribution unit (BDU), which are located inside the battery compartment. The circuit board 24 can be mounted on the battery cell 21 or positioned beside it, and is isolated from the battery cell 21, for example, by a partition 15. The circuit board 24 is connected to the battery cell 21 and to the battery distribution unit 23 to achieve electrical control of the battery pack. The circuit board 24 is, for example, a flexible printed circuit board (FPC).

[0069] The battery pack circuit breaker unit 23 is disposed beside the battery cells 21, for example, on one side of opposite sides of these battery cells 21, and is isolated from these battery cells 21 by a partition 15. The battery pack circuit breaker unit 23 and the circuit board 24 can be located on opposite sides of the battery cells 21. The battery pack circuit breaker unit 23 is also connected to the battery cells 21 and is used for power distribution to achieve stable charging and discharging of the battery pack. The battery pack circuit breaker unit 23 includes components, which may be one of a fuse, a main positive relay, a main negative relay, a pre-charge relay, a pre-charge resistor, or a sensor.

[0070] Continue reading Figure 1 and Figure 2 The battery pack also includes a thermal safety protection system 70, which is located inside the battery box and covers at least one battery cell 21. For example, such as Figure 1 As shown, each battery cell 21 is equipped with a corresponding thermal safety protection system 70, meaning that the thermal safety protection system 70 covers one battery cell 21, and there is a one-to-one correspondence between the thermal safety protection system 70 and the battery cell 21. For example, as... Figure 2As shown, at least two adjacent battery cells 21 are each provided with a thermal safety protection system 70. That is, the thermal safety protection system 70 covers two or more adjacent battery cells 21, and the thermal safety protection system 70 corresponds to at least two battery cells 21. These battery cells 21 can be arranged in parallel and multiple series, or multiple parallel and multiple series. Using the thermal safety protection system 70, a jet channel can be provided in the event of thermal runaway, making the jet direction controllable, thereby preventing thermal runaway propagation caused by lateral jets and improving the safety of the battery pack.

[0071] See Figures 1 to 4 The thermal safety protection system 70 includes a first side plate 31, a second side plate 41, and a third side plate. The first side plate 31 is located on the side of the battery cell 21 where the explosion-proof valve is located. The first side plate 31 has a drain portion 36, which is opposite to the explosion-proof valve. The second side plate 41 is connected to one end of the first side plate 31. The third side plate 51 is connected to the other end of the second side plate 41. The third side plate 51 and the second side plate 41 are located on opposite sides of the battery cell 21 along a first direction. The drain portion 36 allows the jet generated by thermal runaway to be ejected, thereby controlling the jet direction and preventing lateral jetting.

[0072] It is understandable that the first side plate 31 is located above the battery cell 21, the explosion-proof valve is located on the top of the battery cell 21, the second side plate 41 and the third side plate 51 are located at both ends of the first side plate 31 respectively, and the thermal safety protection system 70 formed is covered on the battery cell 21. The bottom of the battery cell 21 is exposed, which makes it easy to fix the battery cell 21 in the battery box using structural adhesive or the like.

[0073] In this design, one end of the first side plate 31 is connected to one end of the second side plate 41, for example, as a single unit. The other end of the first side plate 31 is also connected to the other end of the second side plate 41, for example, as a single unit. The second side plate 41 and the third side plate 51 are arranged opposite each other along a first direction, for example, parallel to the thickness direction of the battery cell 21. Thus, the second side plate 41 and the third side plate 51 face the larger surface area of ​​the battery cell 21, effectively isolating the battery cell 21 and replacing traditional aerogel insulation sheets, thereby improving heat insulation and protection. The aforementioned larger surface area refers to the side of the battery cell 21 with the largest surface area.

[0074] In some possible examples, the first side plate 31, the second side plate 41, and the third side plate 51 can all be flat plates, forming a U-shaped or H-shaped structure. Along the extending direction of the thermal safety protection system 70, the opposite ends of the first side plate 31, the second side plate 41, and the third side plate 51 are aligned with each other, meaning the ends of the thermal safety protection system 70 are flat. Figure 3 As shown, the left ends of the first side plate 31, the second side plate 41, and the third side plate 51 are aligned, and the right ends of the first side plate 31, the second side plate 41, and the third side plate 51 are aligned. The extension direction of the thermal safety protection system 70 can further be consistent with the length direction of the battery cell 21.

[0075] The first side plate 31 is provided with a drainage section 36, which is opposite to the explosion-proof valve. The drainage section 36 is, for example, a weak point on the first side plate 31. In the event of thermal runaway, the jet ejected from the explosion-proof valve can easily break through the drainage section 36 and be ejected outwards. The first side plate 31 also has a hole 37 that penetrates the first side plate 31 to expose a QR code on the battery cell 21. The QR code is used to store and track relevant information about the battery cell 21. The hole 37 and the drainage section 36 are spaced apart. The location of the drainage section 36 is related to the position of the explosion-proof valve. The hole 37 and the drainage section 36 can be changed according to the specific shape of the battery cell 21. For example, the explosion-proof valve can be located in the middle area of ​​the battery cell 21, the drainage section 36 in the middle area of ​​the first side plate 31, and the hole 37 in the edge area of ​​the first side plate 31. Of course, the hole 37 can also be located in other areas of the thermal safety protection system as needed.

[0076] In an example where the thermal safety protection system 70 corresponds to at least two adjacent battery cells 21, the thermal safety protection system 70 has a drain section 36 that spans across at least two battery cells 21, meaning that the orthographic projection of the drain section 36 onto the battery cell 21 covers all the explosion-proof valves. Alternatively, the thermal safety protection system 70 has at least two drain sections 36, each drain section 36 being opposite to an explosion-proof valve of one battery cell 21, meaning that the drain section 36 is opposite to an explosion-proof valve one-to-one.

[0077] See some possible examples. Figure 3 and Figure 4 The first side plate 31 includes a first insulating layer 32, a first heat insulation layer 33, and a first encapsulation layer 34 stacked sequentially in the direction away from the battery cell; the first insulating layer 32 has a first window 35, which is opposite to the explosion-proof valve; the first encapsulation layer 34 has a second window 55, which is opposite to the first window 35; the first heat insulation layer 33 exposed in the first window 35 and the second window 55 ruptures when the battery cell 21 experiences thermal runaway, and the first window 35, the second window 55, and the first heat insulation layer 33 exposed in the first window 35 and the second window 55 form a drainage portion 36.

[0078] The first insulating layer 32 is adjacent to the battery cell 21, the first heat insulation layer 33 is disposed on the side of the first insulating layer 32 away from the battery cell 21, and the first encapsulation layer 34 is disposed on the side of the first heat insulation layer 33 away from the battery cell 21. The first insulating layer 32 has a first window 35, and the explosion-proof valve is exposed within the first window 35. For example, the orthographic projection of the first insulating layer 32 on the battery cell 21 is spaced apart from the orthographic projection of the explosion-proof valve on the battery cell 21, that is, the outer periphery of the explosion-proof valve is within the inner periphery of the first window 35. The shape of the first window 35 can be rectangular, elliptical, or oblong, etc.

[0079] In some possible implementations, the first insulating layer 32 can be an organic solvent coating. An organic solvent coating refers to a solution formed by dissolving a film-forming substance (such as resin, polymer, etc.) in an organic solvent (such as acetone, toluene, ethanol, etc.), which is applied to the surface of a substrate by spraying, brushing, or dipping, and a solid coating is formed after the solvent evaporates.

[0080] For example, the organic solvent coating has a material ratio of 52% epoxy resin, 32% xylene, 10% calcium carbonate, 2% defoamer, and 4% titanium dioxide to improve its mechanical strength and heat resistance. The preparation steps of this organic solvent coating are as follows: epoxy resin base material and xylene are added to a mixing container and stirred until homogeneous; calcium carbonate and titanium dioxide are gradually added, and stirring continues until uniformly dispersed; defoamer is added to adjust the leveling and defoaming properties of the coating; the mixture is filtered to remove impurities, obtaining the final spray coating.

[0081] The first heat insulation layer 33 covers the first window 35, effectively sealing it and providing some dust protection for the battery cell 21. For example, the first heat insulation layer 33 can be a single layer, with its outer periphery aligned with the outer periphery of the first insulation layer 32. The first heat insulation layer 33 is prone to cracking, providing a path for the jet to exit in the event of thermal runaway. The first heat insulation layer 33 is an organic fiber layer, such as COCOON. COCOON is an organic, lightweight, fire-resistant board with excellent heat insulation properties, capable of withstanding temperatures up to 1200℃ while maintaining its original shape. When the temperature reaches 200℃, triggering thermal crystallization, its heat insulation performance doubles. Its thermal conductivity is 0.1 W / mK at temperatures below 200℃ and 0.03 W / mK at temperatures above 200℃.

[0082] The first encapsulation layer 34 has a second window 55 opposite to the first window 35 for jet ejection. In the stacking direction of the first encapsulation layer 34, the first heat insulation layer 33, and the first insulating layer 32, the second window 55 and the first window 35 may at least partially overlap, for example, the first window 35 and the second window 55 may completely overlap, i.e., their inner circumferences are aligned. The first window 35, the second window 55, and the first heat insulation layer 33 exposed within the first and second windows 35 form a drainage portion 36. In the event of thermal runaway, the first insulating layer 32 and the first encapsulation layer 34 block the jet, causing the jet to pass through the first heat insulation layer 33 via the first window 35 and exit through the second window 55, preventing lateral jetting and reducing heat diffusion.

[0083] In some possible implementations, the first encapsulation layer 34 is a water-based spray resin material layer or a polycarbonate (PC) layer. A water-based spray resin material layer refers to a coating formed on the surface of a substrate through a spraying process, using a water-based resin as the main film-forming substance. Examples of water-based spray resin material layers include water-based acrylic resin layers, water-based polyurethane resin layers, water-based epoxy resin layers, water-based fluorocarbon resin layers, and water-based silicone resin layers.

[0084] For example, the material ratio of the water-based spray resin material layer is 55% epoxy resin, 25% water, 15% calcium carbonate, 2% defoamer, and 3% titanium dioxide to improve its heat resistance. The preparation steps of this water-based spray resin material layer are as follows: add epoxy resin base material and water to a mixing container and stir evenly; gradually add calcium carbonate and titanium dioxide, and continue stirring until uniformly dispersed; add defoamer to adjust the leveling and defoaming properties of the coating; filter the mixture to remove impurities and obtain the final spray coating.

[0085] Continue reading Figure 3 and Figure 4 The second side plate 41 includes a second insulating layer 42, a second heat insulation layer 43, and a second encapsulation layer 44 stacked sequentially in the direction away from the battery cell 21; the third side plate 51 includes a third insulating layer 52, a third heat insulation layer 53, and a third encapsulation layer stacked sequentially in the direction away from the battery cell 21. The second insulating layer 42 and the third insulating layer 52 can be referenced to the first insulating layer 32, the second heat insulation layer 43 and the third heat insulation layer 53 can be referenced to the first heat insulation layer 33, and the second encapsulation layer 44 and the third encapsulation layer 54 can be referenced to the first encapsulation layer 34, and will not be described in detail here.

[0086] In some possible examples, the first insulating layer 32, the second insulating layer 42, and the third insulating layer 52 are made of the same material, the first heat insulation layer 33, the second heat insulation layer 43, and the third heat insulation layer 53 are made of the same material, and the first encapsulation layer 34, the second encapsulation layer 44, and the third encapsulation layer 54 are made of the same material, in order to facilitate fabrication.

[0087] The first insulating layer 32, the second insulating layer 42, and the third insulating layer 52 are integrally formed; and / or, the first encapsulation layer 34, the second encapsulation layer 44, and the third encapsulation layer 54 are integrally formed; and / or, the first heat insulation layer 33, the second heat insulation layer 43, and the third heat insulation layer 53 are integrally formed. This improves the connection reliability of the first insulating layer 32, the second insulating layer 42, and the third insulating layer 52; the connection reliability of the first encapsulation layer 34, the second encapsulation layer 44, and the third encapsulation layer 54; and the connection reliability of the first heat insulation layer 33, the second heat insulation layer 43, and the third heat insulation layer 53; it also facilitates manufacturing.

[0088] For example, see Figures 3 to 6An insulating layer 61 is sprayed onto one side surface of the heat insulation layer 62, and an encapsulation layer 63 is sprayed onto the other side surface to form a laminated structure 60. The laminated structure 60 is bent to form a first side plate 31, a second side plate 41, and a third side plate 51. The heat insulation layer forms a corresponding first heat insulation layer 33, a second heat insulation layer 43, and a third heat insulation layer 53. The insulating layer 61 forms a corresponding first insulating layer 32, a second insulating layer 42, and a third insulating layer 52. The encapsulation layer forms a corresponding first encapsulation layer 34, a second encapsulation layer 44, and a third encapsulation layer 54.

[0089] In some possible examples, the thermal safety protection system 70 also includes a fourth side plate, which connects the second side plate 41 and the third side plate 51 and is opposite to the first side plate 31. The thermal safety protection system 70 is sleeved over the battery cell 21. The first side plate 31, the second side plate 41, the fourth side plate, and the third side plate 51 are sequentially connected end to end along the outer periphery of the battery cell 21 to form a sleeve shape, which can cover the entire outer periphery of the battery cell 21 and reduce the jet spraying to other battery cells 21 in the event of thermal runaway. To fix the battery cell 21, the battery cell 21, the fourth side plate, and the battery box can be connected by structural adhesive, which impregnates the fourth side plate and contacts the top of the battery cell 21.

[0090] The specific structure of the fourth side plate can be referred to the first side plate 31, the second side plate 41, and the third side plate 51, and will not be described again here. The thermal safety protection system 70 formed by the first side plate 31, the second side plate 41, the third side plate 51 and the fourth side plate has openings at both ends, which facilitates the exposure of the tabs 22 of the battery cell 21 for connection, thereby realizing the connection of multiple battery cells 21.

[0091] The thermal safety protection system 70 provided in this embodiment is disposed on the battery cell 21. It includes a first side plate 31, a second side plate 41, and a third side plate 51. The first side plate 31 is located on the side of the battery cell 21 where the explosion-proof valve is located. The first side plate 31 has a drain portion 36, which is opposite to the explosion-proof valve. The second side plate 41 is connected to one end of the first side plate 31. The third side plate 51 is connected to the other end of the second side plate 41. The third side plate 51 and the second side plate 41 are located on opposite sides of the battery cell 21 along a first direction. The second side plate 41 and the third side plate 51 isolate the battery cell 21, and the drain portion 36 on the first side plate 31 provides a jet channel in case of thermal runaway, allowing the jet to be ejected along the drain portion 36, thereby controlling the jet direction, avoiding lateral jetting, reducing thermal runaway propagation, and improving the safety of the battery pack.

[0092] The embodiments or implementation methods described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. In this specification, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with an embodiment or example that are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0093] Finally, it should be noted that other embodiments of this utility model will readily occur to those skilled in the art upon consideration of the specification and practice of the utility model disclosed herein. This utility model is intended to cover any variations, uses, or adaptations of this utility model that follow the general principles of this utility model and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this utility model is limited only by the appended claims.

Claims

1. A thermal safety protection system, characterized in that, The battery cell is covered by a protective cover, the battery cell has an explosion-proof valve, and the thermal safety protection system includes: The first side plate is located on the side of the battery cell where the explosion-proof valve is located. The first side plate has a drainage part, which is opposite to the explosion-proof valve. The second side plate is connected to one end of the first side plate; The third side plate is connected to the other end of the second side plate, and the third side plate and the second side plate are respectively located on opposite sides of the battery cell along the first direction.

2. The thermal safety protection system according to claim 1, characterized in that, The first side plate includes: a first insulating layer, a first heat insulation layer, and a first encapsulation layer stacked sequentially along the direction away from the battery cell; The first insulating layer has a first window, which is opposite to the explosion-proof valve; The first encapsulation layer has a second window, which is opposite to the first window; The first thermal insulation layer exposed within the first window and the second window ruptures during thermal runaway of the battery cell, and the first window, the second window, and the first thermal insulation layer exposed within the first window and the second window form the drainage portion.

3. The thermal safety protection system according to claim 2, characterized in that, The first insulating layer is an organic solvent coating; And / or, the first insulation layer is an organic fiber layer; And / or, the first encapsulation layer is an aqueous spray resin material layer or a polycarbonate layer.

4. The thermal safety protection system according to claim 2, characterized in that, The second side plate includes: a second insulating layer, a second heat insulation layer, and a second encapsulation layer stacked sequentially along the direction away from the battery cell; The third side plate includes a third insulating layer, a third heat insulation layer, and a third encapsulation layer stacked sequentially along the direction away from the battery cell.

5. The thermal safety protection system according to claim 4, characterized in that, The first insulating layer, the second insulating layer, and the third insulating layer are an integral structure; And / or, the first encapsulation layer, the second encapsulation layer, and the third encapsulation layer are an integral structure; And / or, the first heat insulation layer, the second heat insulation layer and the third heat insulation layer are an integral structure.

6. The thermal safety protection system according to any one of claims 1-5, characterized in that, The thermal safety protection system also includes: The fourth side plate connects the second side plate and the third side plate and is opposite to the first side plate. The thermal safety protection system is sleeved on the outside of the battery cell.

7. The thermal safety protection system according to any one of claims 1-5, characterized in that, The battery cell is multiple, and each battery cell is equipped with a corresponding thermal safety protection system; Alternatively, at least two adjacent battery cells may be provided with a corresponding thermal safety protection system, the drain section of which corresponds to the explosion-proof valve.

8. The thermal safety protection system according to any one of claims 1-5, characterized in that, The first direction is parallel to the thickness direction of the battery cell; The explosion-proof valve is disposed on one of the two opposite sides of the battery cell along its width direction; The battery cell also has tabs, which are disposed on at least one of the opposite sides of the battery cell along its length.

9. A battery pack, characterized in that, include: Battery box; At least one battery cell is disposed in the battery box, and each battery cell has an explosion-proof valve; The thermal safety protection system as described in any one of claims 1-8 is disposed inside the battery box, and the thermal safety protection system covers at least one of the battery cells.

10. The battery pack according to claim 9, characterized in that, The battery cell has at least two cells, and the battery pack further includes a connecting piece disposed inside the battery box and connecting adjacent battery cells; And / or, The battery box includes a box body and a box cover connected to the box body; And / or, The battery pack further includes a circuit board and a battery pack circuit breaker unit, which are disposed inside the battery box. The battery pack circuit breaker unit is connected to the battery cell, and the circuit board is connected to both the battery cell and the battery pack circuit breaker unit.

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