Functional layer, battery and power consuming device

Abstract

The application belongs to the technical field of batteries, and particularly relates to a functional layer, a battery, a battery pack and a power utilization device, the functional layer comprising a flame-retardant base layer, the flame-retardant base layer comprising a heat-absorbing and decomposing type flame retardant; a heat-sensitive layer, the heat-sensitive layer being arranged on one side of the flame-retardant base layer and comprising a heterojunction semiconductor material; and a protective layer, the protective layer being arranged on the side of the heat-sensitive functional layer away from the flame-retardant base layer and comprising a heat-conducting material. The functional layer is used in a battery, can realize superfast response to temperature change, has high temperature resolution and accurate positioning, can release flame-retardant gas under high-temperature conditions, and the protective layer can quickly transmit heat out, so that the multi-level protection strategy can effectively relieve the heat runaway condition under various conditions, and the reliability of the system and the ability to cope with complex conditions are enhanced.

Description

Technical Field

[0001] This application belongs to the field of battery technology, specifically relating to functional layers, batteries, and electrical devices. Background Technology

[0002] Thermal runaway is a major safety hazard in batteries, and preventing it has always been one of the challenges in battery technology. While some solutions have been proposed in related technologies, problems remain, including slow response speed, low positioning accuracy, the risk of failure of single protection mechanisms, and insufficient structural reliability and durability. Therefore, technologies related to battery thermal runaway analysis and early warning still need improvement. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, this invention proposes a multi-layered protection strategy, a functional layer with high structural reliability and durability, a battery, and an electrical device.

[0004] In a first aspect, this application provides a functional layer. According to an embodiment of this application, the functional layer includes: a flame-retardant substrate layer comprising an endothermic decomposition type flame retardant; a thermistor layer disposed on one side of the flame-retardant substrate layer and comprising a heterojunction semiconductor material; and a protective layer disposed on the side of the thermistor layer away from the flame-retardant substrate layer and comprising a thermally conductive material. This functional layer offers high temperature resolution, accurate positioning, a multi-layered protection strategy, high structural reliability, and strong durability.

[0005] According to embodiments of this application, the endothermic decomposition type flame retardant includes at least one of aluminum phosphate glass powder and mica powder.

[0006] According to embodiments of this application, the heterojunction semiconductor material includes at least one of ZnO / Co3O4 heterojunction semiconductor material and TiO2 / Cu2O heterojunction semiconductor material.

[0007] According to an embodiment of this application, the particle size of the heterojunction semiconductor material is 50nm~80nm.

[0008] According to embodiments of this application, the thermally conductive material includes a linear thermally conductive material, which includes at least one of silicon carbide nanowires and carbon nanotubes.

[0009] According to embodiments of this application, the flame-retardant matrix layer further includes at least one of MXene nanosheets and a resin, wherein the resin includes at least one of epoxy resin and phenolic resin.

[0010] According to embodiments of this application, the thermosensitive layer further includes a carbon material, which includes at least one of graphene oxide and carbon nanotubes.

[0011] According to embodiments of this application, the protective layer further includes a matrix material, which includes at least one of fluorinated polyimide and polytetrafluoroethylene.

[0012] According to embodiments of this application, the flame-retardant matrix layer comprises, by weight percentage: 40wt% to 50wt% of the endothermic decomposition type flame retardant; 10wt% to 25wt% of the MXene nanosheets; and 25wt% to 50wt% of the resin.

[0013] According to an embodiment of this application, the thermal layer comprises, by weight percentage: 70wt% to 80wt% of the heterojunction semiconductor material; and 20wt% to 30wt% of the carbon material.

[0014] According to an embodiment of this application, the protective layer comprises, by weight percentage: 80wt% to 85wt% of the thermally conductive material; and 5wt% to 20wt% of the matrix material.

[0015] According to an embodiment of this application, the axial direction of the linear thermally conductive material is parallel to the protective layer.

[0016] According to an embodiment of this application, the diameter of the linear thermally conductive material is 100nm to 200nm.

[0017] According to an embodiment of this application, the aspect ratio of the linear thermally conductive material is ≥50.

[0018] In a second aspect, this application provides a battery. According to an embodiment of this application, the battery includes at least one single cell, the single cell including a casing, and at least a portion of the surface of the casing having the aforementioned functional layer disposed, wherein a flame-retardant substrate layer in the functional layer is disposed close to the casing.

[0019] According to an embodiment of this application, the battery further includes a control unit, which is electrically connected to the functional layer.

[0020] According to an embodiment of this application, the functional layer includes a plurality of sub-layers, which are disposed at intervals on the surface of the housing.

[0021] According to an embodiment of this application, the battery includes a tab, and at least a portion of the surface of the tab is provided with the functional layer.

[0022] According to embodiments of this application, the functional layer located on the tab is configured as a spiral or concentric ring.

[0023] According to an embodiment of this application, the battery includes a high-voltage connection point, and a functional layer is disposed around the high-voltage connection point.

[0024] According to an embodiment of this application, the functional layer surrounding the high-voltage connection point is constructed as a plurality of concentric rings, with the high-voltage connection point located at the center of the concentric rings.

[0025] According to an embodiment of this application, the battery includes lead terminals, and at least a portion of the surface of the lead terminals is provided with the functional layer.

[0026] According to embodiments of this application, the functional layer located on the lead-out terminal is configured as a spiral or concentric ring.

[0027] According to an embodiment of this application, the battery includes a housing, the individual battery cells are housed in a housing space within the housing, and at least a portion of the surface of the housing is provided with the functional layer.

[0028] According to an embodiment of this application, the battery further includes a phase change unit disposed on one side of the functional layer, the phase change unit comprising a phase change material.

[0029] According to an embodiment of this application, the phase change unit includes a copper-nickel alloy capillary network, and the phase change material is filled in the capillaries of the copper-nickel alloy capillary network.

[0030] According to embodiments of this application, the phase change material includes at least one of alkane / expanded graphite composite phase change material, fatty acid / expanded graphite composite phase change material, molten salt / expanded graphite composite phase change material, and paraffin / expanded graphite composite phase change material.

[0031] According to an embodiment of this application, the battery further includes a fire extinguishing agent injection unit.

[0032] According to an embodiment of this application, the fire extinguishing agent spraying unit includes a housing containing a fire extinguishing agent, and a spray nozzle is provided on the housing. The control unit is electrically connected to the spray nozzle and is used to control the opening and closing of the spray nozzle.

[0033] According to embodiments of this application, the extinguishing agent includes at least one of perfluorohexanone / nano-alumina mixed extinguishing agent and perfluorohexanone / graphene nanosheet mixed extinguishing agent.

[0034] According to an embodiment of this application, the battery further includes: an electromagnetic shut-off valve, which is disposed at the positive and negative busbars of the battery, and the control unit is electrically connected to the electromagnetic shut-off valve for controlling the opening and closing of the electromagnetic shut-off valve.

[0035] In a fourth aspect, this application provides an electrical device. According to an embodiment of this application, the electrical device includes the functional layer described above or the battery described above. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the functional layer structure of one embodiment of this application.

[0037] Figure 2 This is a schematic diagram of the structure of a battery according to an embodiment of this application.

[0038] Figure 3 This is a partial structural schematic diagram of a fire extinguishing agent spraying unit according to an embodiment of this application.

[0039] Figure 4 This is a schematic diagram of the structure of the fire extinguishing agent injection port guide channel according to an embodiment of this application. Detailed Implementation

[0040] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0041] In a first aspect, this application provides a functional layer. According to an embodiment of this application, referring to... Figure 1 The functional layer 100 includes: a flame-retardant substrate layer 10, which includes an endothermic decomposition flame retardant; a thermistor layer 20, disposed on one side of the flame-retardant substrate layer 10, comprising a heterojunction semiconductor material; and a protective layer 30, disposed on the side of the thermistor layer 20 away from the flame-retardant substrate layer 10, comprising a thermally conductive material. In this functional layer, the heterojunction semiconductor material in the thermistor layer can form a three-dimensional conductive network, achieving a rapid response of 0.5 seconds and a temperature gradient positioning accuracy of ±5 mm. When the functional layer is used in a battery, it can trigger an early warning signal in the initial stage of thermal runaway within the battery. Under high-temperature conditions, the endothermic decomposition flame retardant in the flame-retardant substrate layer can release flame-retardant gas, while the thermally conductive material in the protective layer has excellent thermal conductivity, allowing for rapid heat dissipation. Using this functional layer in a battery, through a multi-layered protection strategy of the flame-retardant substrate layer, thermistor layer, and protective layer, can effectively mitigate battery thermal runaway, enhancing battery reliability and its ability to cope with complex situations.

[0042] According to embodiments of this application, the endothermic decomposition type flame retardant includes at least one of aluminum phosphate glass powder and mica powder. Therefore, it can melt and form a microporous structure when heated, releasing flame-retardant gases such as NH3, CO2, and H2O. This not only rapidly dissipates heat but also effectively suppresses ignition, ensuring battery safety during thermal runaway.

[0043] According to embodiments of this application, the flame-retardant matrix layer further includes MXene nanosheets. The interlayer electron tunneling effect of MXene nanosheets intensifies with increasing temperature, causing changes in the resistance of the functional layer. By detecting voltage changes in the functional layer, battery temperature changes can be quickly detected, thus providing early warning of battery thermal runaway. Specifically, when a temperature gradient exists between the two ends of the MXene nanosheets, the free electrons at higher temperatures gain higher energy and become more active, diffuse directionally towards the lower-energy, lower-electron-density end. This directional electron migration leads to charge separation at both ends of the MXene nanosheets (i.e., the high-temperature end loses electrons and becomes positively charged, while the low-temperature end gains electrons and becomes negatively charged), ultimately forming a stable potential difference. By detecting this potential difference and combining it with the Seebeck coefficient, the temperature gradient can be calculated, enabling the monitoring of spatial temperature differences with significantly improved positioning accuracy and enhanced ability to identify localized abnormal temperature rise areas.

[0044] According to embodiments of this application, MXene nanosheets can be parallel to the flame-retardant matrix layer or at a certain angle to it. As an example, the arrangement angle of the MXene nanosheets (the angle between the MXene nanosheets and the flame-retardant matrix layer) can be adjusted to 20° to adapt to different application environments and increase structural flexibility.

[0045] In this paper, MXene nanosheets are a class of nanosheets composed of MAX phases (M n+1 AX n Two-dimensional transition metal carbides / nitrides (typically Ti3C2T) are obtained by selectively etching the A layer of a transition metal (M is a transition metal, A is a main group element, and X is C or N). x ).

[0046] According to embodiments of this application, the flame-retardant matrix layer further includes a resin, said resin comprising at least one of epoxy resin and phenolic resin. The resin can form the matrix of the flame-retardant matrix layer, providing good support, while the aforementioned resin also possesses high temperature resistance and tensile strength.

[0047] According to embodiments of this application, the flame-retardant matrix layer, by weight percentage, comprises: 40wt% to 50wt% (specifically, 40wt%, 41wt%, 42wt%, 43wt%, 44wt%, 45wt%, 46wt%, 47wt%, 48wt%, 49wt%, 50wt%, or any two of these ranges) of the endothermic decomposition flame retardant; 10wt% to 25wt% (specifically, 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, 22wt%, 25wt%, or any two of these ranges) of MXene nanosheets; and 25wt% to 50wt% (specifically, 25wt%, 28wt%, 30wt%, 32wt%, 35wt%, 38wt%, 40wt%, 42wt%, 45wt%, 48wt%, 50wt%, or any two of these ranges) of resin. Thus, the flame-retardant matrix layer can both detect temperature and release flame-retardant gases to prevent ignition.

[0048] According to embodiments of this application, the thickness of the flame-retardant substrate layer is 180μm to 220μm, specifically 180μm, 185μm, 190μm, 195μm, 200μm, 210μm, 215μm, 220μm, or any combination thereof. Within this thickness range, the flame-retardant and temperature-detecting effects can be effectively achieved without being excessively thick and occupying too much space, which is beneficial for battery miniaturization.

[0049] According to embodiments of this application, the heterojunction semiconductor material includes at least one of ZnO / Co3O4 heterojunction semiconductor material and TiO2 / Cu2O heterojunction semiconductor material. This facilitates the formation of a three-dimensional conductive network and enables ultrafast response to temperature changes, with a response time of less than 0.5 seconds. It also provides high temperature resolution and significantly improves the ability to identify localized abnormal temperature rise regions.

[0050] According to embodiments of this application, the thermosensitive layer further includes a carbon material, which comprises at least one of reduced graphene oxide and carbon nanotubes. Thus, the carbon material can be composited with a heterojunction semiconductor material to form a three-dimensional conductive network, enhancing the conductivity and mechanical properties of the functional layer. Reduced graphene oxide is a two-dimensional carbon material obtained by reducing graphene oxide using chemical or physical methods.

[0051] According to embodiments of this application, the mass ratio of the heterojunction semiconductor material to the carbon material is 2.33 to 4:1, specifically 2.33:1, 2.5:1, 2.8:1, 3:1, 3.2:1, 3.5:1, 3.8:1, 4:1, or any two of these ratios. Within this range, both fast temperature response and temperature resolution can be achieved simultaneously.

[0052] According to embodiments of this application, the particle size of the heterojunction semiconductor material is 50nm to 80nm, specifically within the range of 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, or any two thereof. Within the aforementioned particle size range, the heterojunction semiconductor material responds to temperature more quickly and has higher sensitivity.

[0053] According to embodiments of this application, the thickness of the thermally sensitive layer is 75μm to 85μm, specifically 75μm, 76μm, 77μm, 78μm, 79μm, 80μm, 81μm, 82μm, 83μm, 84μm, 85μm, or any combination thereof. Within this thickness range, the temperature detection effect is better, and it is less prone to cracking and peeling, while occupying less space.

[0054] According to embodiments of this application, the heterojunction semiconductor material in the thermistor layer can provide a fast response of 0.5s (temperature resolution ±1.5℃), while the MXene nanosheet network in the flame-retardant matrix layer enables spatial temperature gradient monitoring. Together, they constitute a dual-layer temperature sensing mechanism. Specifically, when the local temperature is too high, the heterojunction semiconductor material in the thermistor layer undergoes a phase transition, and the resistance value decreases by at least three orders of magnitude (e.g., from 10...). 6 Ω drops to 10 3 Temperature can be detected by detecting the corresponding voltage signal (Ω); and the interlayer electron tunneling effect of MXene nanosheets increases with increasing temperature, which can be used to detect temperature and temperature gradient. In turn, a thermal runaway warning signal can be triggered by a voltage threshold comparator.

[0055] According to embodiments of this application, the thermistor layer, by weight percentage, comprises: 70wt% to 80wt% (specifically, 70wt%, 71wt%, 72wt%, 73wt%, 74wt%, 75wt%, 76wt%, 77wt%, 78wt%, 79wt%, 80wt%, or any two of these) of the heterojunction semiconductor material; and 20wt% to 30wt% (specifically, 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, 25wt%, 26wt%, 27wt%, 28wt%, 29wt%, 30wt%, or any two of these) of the carbon material. Therefore, the thermistor layer can achieve rapid and precise detection of temperature and temperature gradients, thereby triggering a thermal runaway warning signal and improving battery safety.

[0056] According to embodiments of this application, the thermally conductive material includes a linear thermally conductive material. Therefore, while possessing superior thermal conductivity, it also enhances the wear resistance and adhesion of the functional layer, thereby improving the structural stability of the functional layer and extending its service life.

[0057] In some embodiments, the length direction of the linear thermally conductive material can be parallel to the protective layer, or it can form a certain angle with the protective layer, such as the length direction of the linear thermally conductive material being perpendicular to the protective layer. This enhances the mechanical strength and thermal conductivity of the functional layer.

[0058] According to embodiments of this application, the diameter of the linear thermally conductive material is 100nm to 200nm, specifically within the range of 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm, or any two of these ranges. This improves the high-temperature stability and impact resistance of the protective layer.

[0059] According to embodiments of this application, the aspect ratio of the linear thermally conductive material is ≥50. This helps to increase the flexural strength and crack resistance of the protective layer.

[0060] In this article, the wire diameter of a linear thermally conductive material refers to its outer diameter, and the aspect ratio refers to the ratio of its length to its wire diameter.

[0061] According to embodiments of this application, the linear thermally conductive material includes at least one of silicon carbide nanowires and carbon nanotubes. This results in excellent thermal conductivity, and also increases the surface wear resistance of the functional layer, improves the adhesion of the functional layer, and enhances the long-term stability of the functional layer under extreme environments. Even after repeated use, it maintains a low rate of resistance change (e.g., less than 2% resistance change after 1000 cycles of friction), ensuring long-term reliability and stability, extending its service life, and meeting the stringent safety requirements of battery management systems in applications such as electric vehicles.

[0062] According to embodiments of this application, the protective layer further includes a matrix material. According to embodiments of this application, the matrix material includes at least one of fluorinated polyimide and polytetrafluoroethylene. Therefore, it exhibits good thermal stability and chemical stability, while also being relatively low in cost.

[0063] According to embodiments of this application, the mass ratio of the thermally conductive material to the substrate material is 4~5.67:1, specifically 4:1, 4.2:1, 4.5:1, 4.8:1, 5:1, 5.2:1, 5.5:1, 5.67:1, or any two of these ratios. Within the above ratio range, the protective layer can fully exert its thermal conductivity and reinforcing effects, while also exhibiting strong adhesion, high thermal and chemical stability, and low cost.

[0064] As an example, the protective layer comprises fluorinated polyimide and silicon carbide nanowires. Specifically, fluorinated polyimide is a high-performance polymer with excellent thermal stability, chemical stability, and mechanical properties. Silicon carbide nanowires (SiC nanowires) are a high-strength, high-thermal-conductivity one-dimensional material. The composite material of these two materials, used in the surface protective layer, provides good physical and chemical protection while enhancing the surface's abrasion resistance and thermal conductivity.

[0065] As an example, the protective layer can be made of a composite material of polytetrafluoroethylene (PTFE) and carbon nanotubes. PTFE has better chemical stability and lower cost, while carbon nanotubes have better thermal conductivity.

[0066] According to embodiments of this application, the thickness of the protective layer is 25μm to 35μm, specifically 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, 31μm, 32μm, 33μm, 34μm, 35μm, or any two of these ranges. Within the above thickness range, the protective effect is better, the thermal conductivity is excellent, it is not easy to fall off, and it occupies less space.

[0067] According to an embodiment of this application, the protective layer, by weight percentage, comprises: 80wt% to 85wt% (specifically, 80wt%, 81wt%, 82wt%, 83wt%, 84wt%, 85wt%, or any two thereof) of the thermally conductive material; and 15wt% to 20wt% (15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, or any two thereof) of the matrix material. Therefore, the protective layer has better thermal conductivity and wear resistance, and can provide better protection.

[0068] In a second aspect, this application provides a battery. According to an embodiment of this application, the battery includes at least one single cell, each cell including a casing. At least a portion of the surface of the casing is provided with the aforementioned functional layer, and a flame-retardant substrate layer in the functional layer is disposed close to the casing. This battery can trigger an early warning system for thermal runaway and can delay thermal runaway through a multi-layered protection strategy of the functional layer, significantly improving the battery's safety performance.

[0069] According to an embodiment of this application, the functional layer includes multiple sub-layers, which are spaced apart from each other on the surface of the housing. Thus, each sub-layer can be electrically connected via silver paste wires to form an independent sensing unit, creating a finer temperature monitoring network, improving the accuracy and reliability of temperature monitoring, and consequently enabling more precise positioning of the temperature rise zone.

[0070] It is understandable that there are no particular restrictions on the specific distribution of multiple sublayers on the battery casing, and they can be selected according to actual needs. For example, in areas with relatively uniform temperature distribution, the distribution density of sublayers can be lower, while in areas with large temperature variations, the distribution density of sublayers can be higher, thereby further improving the accuracy of temperature detection and the positioning accuracy of temperature rise areas.

[0071] Furthermore, by setting multiple sub-layers as independent sensing units on the surface of the outer shell, temperature changes at different locations can be monitored in real time, and the specific location of temperature anomalies can be accurately determined. The above-mentioned functional layers can achieve high-precision spatial temperature gradient monitoring.

[0072] According to embodiments of this application, the area of ​​each sublayer is not particularly limited and can be selected according to actual needs. In some embodiments, the size of each sublayer can be 50mm × 50mm.

[0073] According to an embodiment of this application, the single-cell battery includes a tab, and at least a portion of the surface of the tab is provided with the functional layer. Specifically, the tab is the current input / output location of the battery, where the current is relatively large and the heat generation is relatively high. It is likely to be the area with the highest temperature in the single-cell battery. Providing a functional layer on the tab can better detect the temperature of the tab, trigger a temperature rise warning earlier, and thus further improve the safety of the battery.

[0074] According to embodiments of this application, the functional layer located on the tab is constructed as a spiral or concentric ring. This allows for the formation of a three-dimensional or two-dimensional conductive network, increasing the coverage and uniformity of the monitoring area, improving monitoring reliability and response speed, reducing material consumption, increasing manufacturing efficiency, while also providing high temperature resolution and high positioning accuracy.

[0075] In some embodiments, the width of the concentric annular functional layer and the spacing between two adjacent annular rings are not particularly limited. For example, the width of the annular rings can be 15 mm, and the spacing between two adjacent annular rings can be 5 mm. The linewidth and pitch of the spiral functional layer are also not particularly limited. In some embodiments, the pitch can be 3 mm, and the linewidth can be 0.5 mm.

[0076] In some embodiments, the battery may include a single cell, i.e., the battery is a single cell. In other embodiments, the battery may include multiple cells to form a battery pack, and the battery pack may be a battery module, battery pack, etc.

[0077] It is understood that there are no particular restrictions on the specific type of single battery cell. For example, based on the type of active ions, it can include lithium-ion batteries, sodium-ion batteries, etc.; based on the outer packaging, it can include soft-pack batteries, hard-shell batteries, etc.; based on the shape, it can include cylindrical batteries, square batteries, etc.; and based on the electrolyte, it can include liquid batteries, solid-state batteries, etc.

[0078] It is understandable that there are no particular restrictions on the specific structure of a single battery cell, and it can be selected according to actual needs. Taking a liquid battery as an example, it can include a positive electrode, a negative electrode, a separator, an electrolyte, and a casing. The positive electrode, separator, and negative electrode can be made into a bare cell through stacking or winding processes, then housed in the casing, the electrolyte is melted, and the casing is sealed to obtain the battery.

[0079] In some embodiments, the battery may further include a control unit electrically connected to the functional layer. Thus, the functional layer can detect the battery temperature quickly and accurately, and the control unit can trigger a thermal runaway warning based on the temperature detection results of the functional layer. When the temperature rises, the flame-retardant substrate layer can release flame-retardant gas to prevent ignition, while the protective layer can quickly dissipate heat, thereby effectively delaying thermal runaway and improving battery safety.

[0080] In some embodiments, the battery may include a structural component and multiple individual battery cells. The structural component is used to fix the battery, while the multiple individual battery cells may be connected in series or in parallel. The arrangement of the multiple individual battery cells is not particularly limited and can be selected according to actual needs. As an example, the multiple individual battery cells may be arranged in an array.

[0081] According to an embodiment of this application, the battery includes multiple individual cells arranged in an array. The casing of each individual cell includes two opposing large surfaces and a side surface connecting the two large surfaces. The large surfaces of two adjacent individual cells are arranged opposite each other, and the functional layer is disposed on the outer surface of the side surface. Therefore, accurate temperature detection can be achieved while reducing material usage and lowering costs.

[0082] According to an embodiment of this application, multiple individual cells in the battery need to be connected to each other, as well as to the conductive components of the battery, and the connection locations constitute a high-voltage connection point 202 (see reference). Figure 2 This is typically a location with higher temperatures. In this case, the functional layer is arranged around the high-voltage connection point. In some embodiments, the functional layer may include multiple concentric rings 110, with the high-voltage connection point 202 located at the center of the concentric rings 110. This increases the coverage and uniformity of the monitoring area, improves the reliability and response speed of monitoring, and enables more accurate temperature detection and earlier warning of thermal runaway.

[0083] According to the embodiments of this application, referring to Figure 2 The battery 200 includes lead-out terminals 201, and at least a portion of the surface of the lead-out terminals 201 is provided with the functional layer 100. This allows for more accurate detection of high-temperature areas, early warning of thermal runaway, delaying thermal runaway of the battery, and improving its safety.

[0084] According to embodiments of this application, the functional layer located on the lead-out terminal is constructed as a spiral or concentric ring. This allows for the formation of a three-dimensional or two-dimensional conductive network, increasing the coverage and uniformity of the monitoring area, improving monitoring reliability and response speed, reducing material consumption, increasing manufacturing efficiency, while also providing high temperature resolution and high positioning accuracy.

[0085] According to an embodiment of this application, the battery further includes a housing, in which the individual battery cells are housed within a receiving space, and at least a portion of the surface of the housing is provided with the functional layer. This further enhances battery safety.

[0086] According to an embodiment of this application, the battery further includes a phase change unit, which is disposed on one side of the functional layer and includes a phase change material. Specifically, when the temperature reaches the phase change point of the phase change material, the phase change material undergoes a state change, such as changing from a solid to a liquid state, absorbing or releasing a large amount of latent heat during the process to achieve temperature regulation. By setting the phase change unit, heat can be quickly transferred to the phase change material through the protective layer in the functional layer. When the temperature is too high, excessive heat is absorbed, and the heat absorption by the phase change material can effectively delay the thermal runaway of the battery and improve its safety.

[0087] According to an embodiment of this application, the phase change unit includes a copper-nickel alloy capillary network, and the phase change material is filled in the capillaries of the copper-nickel alloy capillary network. Therefore, the phase change material can achieve better heat transfer with the functional layer, reducing the thermal resistance of the heat dissipation path, improving cooling efficiency, quickly dissipating heat to the phase change material, and better delaying thermal runaway.

[0088] According to embodiments of this application, the phase change material includes at least one of alkane / expanded graphite composite phase change materials, fatty acid / expanded graphite composite phase change materials, molten salt / expanded graphite composite phase change materials, and paraffin / expanded graphite composite phase change materials. Therefore, it absorbs more heat, effectively delays thermal runaway, and has lower costs and higher thermal stability.

[0089] According to an embodiment of this application, the battery also includes a fire extinguishing agent spraying unit. This allows for the spraying of fire extinguishing agent, further reducing the possibility of battery fire and significantly increasing its safety performance.

[0090] According to an embodiment of this application, the fire extinguishing agent spraying unit includes a housing containing a fire extinguishing agent, and a spray port 41 is provided on the housing (see reference). Figure 3 The control unit is electrically connected to the nozzle and is used to control the opening and closing of the nozzle. Specifically, the control unit can trigger a thermal runaway warning based on a voltage signal detected by the functional layer, and then control the nozzle to open and begin spraying the extinguishing agent, thereby delaying thermal runaway and improving safety.

[0091] According to embodiments of this application, the extinguishing agent includes at least one of perfluorohexanone / nano-alumina mixed extinguishing agent and perfluorohexanone / graphene nanosheet mixed extinguishing agent. Therefore, it possesses good thermal conductivity and high extinguishing efficiency, and the materials are widely available and cost-effective. Perfluorohexanone is a highly efficient extinguishing agent suitable for extinguishing Class A, B, and C fires; nano-alumina serves as an auxiliary component, improving the stability and coverage efficiency of the extinguishing agent; the mixture of these two can rapidly cover the fire source in the event of a fire, achieving the extinguishing effect.

[0092] According to embodiments of this application, the shape of the injection nozzle is not particularly limited and can be selected according to actual needs. In some embodiments, the injection nozzle can be a hexagonal honeycomb nozzle or a rectangular nozzle. This allows for adaptation to different injection requirements and injection angles.

[0093] According to the embodiments of this application, referring to Figure 3 and Figure 4 The extinguishing agent injection nozzle can be designed with an annular guide channel (inclination angle 22°) 42, which allows the extinguishing agent to form a covering layer with a thickness of >8mm within 0.3s.

[0094] According to embodiments of this application, the location of the extinguishing agent injection unit is not particularly limited and can be selected according to actual needs. In some embodiments, the battery includes an array of individual battery cells arranged in an array, and the extinguishing agent injection unit is located around the periphery of the individual battery cell array. This helps to improve fire extinguishing efficiency. According to an embodiment of this application, the battery further includes an electromagnetic shut-off valve, which is disposed at the positive and negative busbars of the battery. The control unit is electrically connected to the electromagnetic shut-off valve and is used to control the opening and closing of the electromagnetic shut-off valve. Therefore, when the battery temperature is detected to be too high, the control unit can open the electromagnetic shut-off valve to disconnect the circuit and reduce the risk of battery thermal runaway.

[0095] An electromagnetic shut-off valve is a valve that controls the flow of fluids (such as gases and liquids) using electromagnetic principles. In the embodiments of this application, the electromagnetic shut-off valve is installed at the positive and negative busbars of the battery to quickly cut off the circuit when an abnormal temperature is detected, thereby preventing the fault from escalating.

[0096] According to embodiments of this application, the electromagnetic shut-off valve can be made of at least one of stainless steel or copper-nickel alloy. This provides good corrosion resistance and high mechanical strength. In some embodiments, multiple electromagnetic shut-off valves can be used to achieve a multi-point shut-off structure, thereby improving the reliability and response speed of the shut-off.

[0097] In the battery described in this application, the functional layer enables rapid and accurate temperature monitoring and anomaly location, providing a solid foundation for timely intervention. From the perspective of physical structure and material composite design, through the functional layer structure design, phase change unit, fire extinguishing agent injection unit, and electromagnetic shut-off valve linkage mechanism, multi-level physical and chemical design achieves rapid detection and proactive intervention of battery pack thermal runaway, effectively controlling and preventing the occurrence and spread of thermal runaway events, and significantly improving battery safety and reliability. The unique dual-layer sensing mechanism and graded protection design, along with the unique multi-layer structure and material combination, not only provide efficient and accurate temperature monitoring and thermal management but also enhance the mechanical properties and chemical stability of the functional layer. This application achieves real-time early warning and efficient fire suppression for battery thermal runaway through a multi-layered physical and chemical design. It emphasizes a comprehensive protection mechanism that combines local temperature sensing and active intervention, as well as structural reliability and practical application effectiveness. It significantly improves early warning accuracy and fire-retardant effect, ensuring effective mitigation of thermal runaway in various situations. This enhances battery reliability, its ability to cope with complex situations, and its reliability and longevity under extreme conditions.

[0098] As an example, the working principle of the thermal runaway detection and early warning of the battery in this application is as follows: When the local temperature is too high (e.g., >85℃), the heterojunction semiconductor material in the thermistor layer undergoes a phase transition, and the resistance value decreases by at least three orders of magnitude (e.g., from 10). 6 Ω drops to 10 3 Simultaneously, the electron tunneling effect between MXene nanosheets is enhanced, causing changes in the resistance of the functional layer. The control unit detects the voltage changes in the functional layer. When the voltage change exceeds a threshold, a voltage threshold comparator (an electronic circuit used to compare two voltage values ​​and generate an output signal when the input voltage reaches a set threshold; in this embodiment, the voltage threshold comparator is used to monitor the resistance changes in the functional layer, and triggers an early warning signal once the resistance change exceeds a preset range) is activated, which in turn triggers the spraying of the extinguishing agent and the disconnection of the electromagnetic shut-off valve circuit. Meanwhile, the protective layer of silicon carbide nanowires forms a thermally conductive pathway (thermal conductivity can be increased to 35 W / m·K), directing heat to the phase change material. The endothermic decomposition flame retardant melts to form a microporous structure (pore size 2-5 μm), releasing flame-retardant gases such as NH3, CO2, and H2O.

[0099] In a fourth aspect, this application provides an electrical device. According to embodiments of this application, the electrical device includes the aforementioned functional layer or the aforementioned battery. This electrical device has a lower risk of thermal runaway and higher safety.

[0100] According to embodiments of this application, the specific type of electrical device is not particularly limited and can be any device that uses a battery as a power source or energy storage unit. As examples, electrical devices include, but are not limited to, electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), mobile terminals (e.g., mobile phones, laptops, game consoles, wearable devices, etc.), drones, aerospace equipment, satellites, ships, energy storage systems, etc.

[0101] It is understandable that, in addition to the battery mentioned above, the electrical device also includes necessary structures and components, all of which can be made with reference to conventional technologies. For example, an electric vehicle may include a body, chassis, tires, navigation system, radar system, steering system, braking system, lubrication system, cooling system, driving system, etc., which will not be described in detail here.

[0102] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0103] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0104] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0105] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "beneath" of the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0106] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. 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 may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0107] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A functional layer, characterized in that, include: A flame-retardant matrix layer, wherein the flame-retardant matrix layer comprises an endothermic decomposition type flame retardant; A thermal layer, wherein the thermal layer is disposed on one side of the flame-retardant substrate layer, and comprises a heterojunction semiconductor material; A protective layer, disposed on the side of the heat-sensitive layer away from the flame-retardant substrate layer, includes a thermally conductive material.

2. The functional layer according to claim 1, characterized in that, At least one of the following conditions must be met: The endothermic decomposition type flame retardant includes at least one of aluminum phosphate glass powder and mica powder; The heterojunction semiconductor material includes at least one of ZnO / Co3O4 heterojunction semiconductor material and TiO2 / Cu2O heterojunction semiconductor material; The heterojunction semiconductor material has a particle size of 50nm~80nm; The thermally conductive material includes a linear thermally conductive material, which includes at least one of silicon carbide nanowires and carbon nanotubes. The flame-retardant matrix layer further includes at least one of MXene nanosheets and a resin, wherein the resin includes at least one of epoxy resin and phenolic resin; The thermal layer also includes a carbon material, which includes at least one of graphene oxide and carbon nanotubes; The protective layer also includes a matrix material, which includes at least one of fluorinated polyimide and polytetrafluoroethylene.

3. The functional layer according to claim 2, characterized in that, At least one of the following conditions must be met: The flame-retardant matrix layer comprises, by weight percentage: 40wt%–50wt% of the endothermic decomposition flame retardant; 10wt%–25wt% of MXene nanosheets; and 25wt%–50wt% of the resin. The thermal layer comprises, by weight percentage: 70wt% to 80wt% of the heterojunction semiconductor material; and 20wt% to 30wt% of the carbon material; The protective layer comprises, by weight percentage: 80wt% to 85wt% of the thermally conductive material; and 15wt% to 20wt% of the matrix material.

4. The functional layer according to claim 2 or 3, characterized in that, At least one of the following conditions must be met: The axial direction of the linear thermally conductive material is parallel to the protective layer; The diameter of the linear thermal conductive material is 100 nm to 200 nm. The aspect ratio of the linear thermally conductive material is ≥50.

5. A battery, characterized in that, It includes at least one single battery cell, the single battery cell including a housing, and a functional layer according to any one of claims 1 to 4 is disposed on at least a portion of the surface of the housing, wherein a flame-retardant matrix layer in the functional layer is disposed close to the housing.

6. The battery according to claim 5, characterized in that, It also includes a control unit, which is electrically connected to the functional layer.

7. The battery according to claim 5 or 6, characterized in that, At least one of the following conditions must be met: The functional layer includes multiple sub-layers, which are spaced apart from each other on the surface of the outer shell; The single battery cell includes a tab, and at least a portion of the surface of the tab is provided with the functional layer; The battery includes multiple individual cells arranged in an array. The outer casing of each individual cell includes two opposing large surfaces and a side surface connecting the two large surfaces. The large surfaces of two adjacent cells are arranged opposite each other, and the functional layer is disposed on the outer surface of the side surface. The battery includes a high-voltage connection point, and the functional layer is arranged around the high-voltage connection point; The battery includes lead terminals, and at least a portion of the surface of the lead terminals is provided with the functional layer; The battery includes a housing, and the individual battery cells are housed in a housing space within the housing. At least a portion of the surface of the housing is provided with the functional layer.

8. The battery according to claim 7, characterized in that, At least one of the following conditions must be met: The functional layer located on the tab is constructed as a spiral or concentric ring; The functional layer surrounding the high-voltage connection point is constructed as multiple concentric rings, with the high-voltage connection point located at the center of the concentric rings; The functional layer located on the lead-out terminal is configured as a spiral or concentric ring.

9. The battery according to any one of claims 5 to 8, characterized in that, Also includes: A phase change unit, disposed on one side of the functional layer, includes a phase change material.

10. The battery according to claim 9, characterized in that, At least one of the following conditions must be met: The phase change unit includes a copper-nickel alloy capillary network, and the phase change material is filled in the capillaries of the copper-nickel alloy capillary network. The phase change material includes at least one of the following: alkane / expanded graphite composite phase change material, fatty acid / expanded graphite composite phase change material, molten salt / expanded graphite composite phase change material, and paraffin / expanded graphite composite phase change material.

11. The battery according to any one of claims 5 to 10, characterized in that, It also includes a fire extinguishing agent injection unit.

12. The battery according to claim 11, characterized in that, At least one of the following conditions must be met: The fire extinguishing agent spraying unit includes a housing containing a fire extinguishing agent, and a spray nozzle is provided on the housing. A control unit is electrically connected to the spray nozzle and is used to control the opening and closing of the spray nozzle. The extinguishing agent includes at least one of perfluorohexanone / nano-alumina mixed extinguishing agent and perfluorohexanone / graphene nanosheet mixed extinguishing agent.

13. The battery according to any one of claims 5 to 12, characterized in that, Also includes: An electromagnetic shut-off valve is provided at the positive and negative busbars of the battery. A control unit is electrically connected to the electromagnetic shut-off valve and is used to control the opening and closing of the electromagnetic shut-off valve.

14. An electrical appliance, characterized in that, It includes the functional layer as described in any one of claims 1 to 4 and the battery as described in any one of claims 5 to 13.

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