Multifunctional assembly for safe operation and disaster prevention and control of lithium ion battery

Abstract

The invention provides a multifunctional assembly for safe operation and disaster prevention and control of a lithium ion battery, and belongs to the technical field of lithium ion batteries. Comprising a substrate layer, a functional layer and a packaging layer, the substrate layer comprises a substrate, and polyimide is uniformly grown on the surface of the substrate in situ by adopting an in-situ generation mode to form a layer of polyimide film. The functional layer comprises heating wires and sensors, and the heating wires and the sensors are arranged on one side or two sides of the substrate layer in a staggered mode in space projection and do not interfere with each other. A packaging layer is formed on the upper surface of the functional layer. According to the invention, a heat-insulating flame-retardant material is used as a matrix, so that the module has better heat-insulating and flame-retardant characteristics, and can provide buffering for adjacent batteries when the batteries are subjected to thermal runaway. By adopting the flexible in-situ integrated heating wire and the multifunctional sensing layer, low-temperature preheating and signal sensing of the battery in an unstressed mode are realized, and the safe operation and disaster prevention and control capability of the battery are effectively improved.

Description

Technical Field

[0001] This invention provides a multifunctional component for the safe operation and disaster prevention of lithium-ion batteries, belonging to the field of lithium-ion battery technology. Background Technology

[0002] Lithium-ion batteries have become commonly used energy storage devices due to their high energy density and long cycle life. However, their performance degrades significantly at low temperatures, accompanied by thermal safety risks. Low temperatures increase electrolyte viscosity, decrease ionic conductivity, and drastically increase internal resistance, affecting power output. During charging, lithium dendrite growth can easily occur, puncturing the separator and causing short circuits or even thermal runaway. Effective low-temperature heating technology is crucial for ensuring the safe operation of batteries over a wide temperature range. Existing technologies mainly include internal heating and external heating. Internal heating relies on the battery's own heat generation, which is highly efficient, but often requires adjustments to the battery structure or complex control, affecting battery performance and lifespan, and has high technical barriers and risks. External heating involves adding heating elements to the outside of the battery to heat the surface, and is currently the mainstream solution. However, current external heating solutions are relatively simple in function, often resulting in uneven heating, and cannot be adjusted according to the battery's condition.

[0003] Existing technologies also have shortcomings in battery status monitoring and safety protection. Most monitoring methods use external rigid sensors, which are difficult to attach to the battery surface, easily leading to signal delays or failure under impact. Thermal safety protection materials such as insulation cotton and aerogel pads are mostly passive protection, lacking coordination with the thermal management system and unable to intervene in the early stages of thermal runaway. Furthermore, the expansion generated during battery cycling often fails to release effectively, accelerating battery aging and affecting battery life. Although the development of flexible electronics technology has brought new possibilities for thermal management, most existing flexible components are multifunctional, failing to integrate heating, multi-parameter sensing, thermal insulation and flame retardancy, and stress buffering functions, often failing to meet the comprehensive needs of complex operating conditions in real-world applications. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a highly integrated, structurally stable, and functionally synergistic component that simultaneously achieves the following three core functions, thereby improving the performance and safety of lithium-ion batteries over a wider temperature range and under complex operating conditions:

[0005] (1) Low-temperature heating function. Through a low-power, high-efficiency heating circuit, the battery is provided with rapid and uniform preheating, which fundamentally solves the problems of battery start-up difficulties, performance degradation and lithium plating on the charging negative electrode caused by low ambient temperature.

[0006] (2) Multi-parameter real-time safety monitoring function. Through in-situ integrated flexible sensors, the battery's temperature, pressure, gas and other parameters are collected and identified in real time, enabling early identification and intervention of battery safety risks.

[0007] (3) Disaster prevention and control function. Through the substrate (1) material and packaging design that has the characteristics of heat insulation, flame retardancy and stress buffering, when the battery experiences thermal runaway, it can effectively delay the heat diffusion and suppress the spread of flames, thus buying more time for the safe handling of the system.

[0008] The complete technical solution provided by this invention:

[0009] A multifunctional component for safe operation and disaster prevention of lithium-ion batteries includes a substrate layer, a functional layer and an encapsulation layer;

[0010] The substrate layer includes a matrix, which is an aerogel felt with a density of 0.12-0.18 g·cm⁻³. Polyimide is uniformly grown in situ on the matrix surface using an in-situ generation method, forming a polyimide film on the aerogel felt surface. The functional layer includes heating wires and sensors, which are spatially staggered on one or both sides of the substrate layer without interfering with each other; an encapsulation layer is formed on the upper surface of the functional layer.

[0011] Furthermore, the method for preparing the polyimide film is as follows:

[0012] First, the substrate aerogel felt is pretreated by drying it in a vacuum at 80°C for 2 hours. After cooling to room temperature, it is stored in a desiccator for later use.

[0013] Next, the surface treatment solution was prepared by dissolving 3-aminopropyltriethoxysilane at 0.5 vol% in a 95 / 5 volume ratio of anhydrous ethanol / water mixture, and adjusting the pH to 5 with glacial acetic acid. The pretreated aerogel mat was sprayed or immersed in the surface treatment solution for 30 seconds, spun dry, and then dried at 80°C for 3 minutes.

[0014] Immediately after removal, proceed with the subsequent polyamic acid coating. Use a polyamic acid solution with a solid content of 30%-70%, applied by a blade coating method with a gap of 80–120 µm. Then, perform staged curing in air: 80℃, 30–60 min; 120℃, 45–60 min; 180℃, 60–90 min; 230℃, 90–120 min; 260–280℃, 30–60 min.

[0015] In the polyamic acid structure:

[0016] The dianhydrides are one of the following: pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 4,4'-oxophthalic acid dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride, 4,4'-(hexafluoroisopropyl)phthalic acid dianhydride, and 4,4'-(4,4'-isopropyldiphenoxy)bis(phthalic anhydride);

[0017] The diamine is one of 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylmethane, 1,3-bis(4-aminophenoxy)benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, and bis(3-aminopropyl)-terminated polydimethylsiloxane.

[0018] Furthermore, the heating wire is formed in situ on the substrate surface using flexible resistive material with heat generation effect in a linear, tortuous manner through flexible printing, screen printing, chemical deposition, or other methods.

[0019] Furthermore, the sensor is fabricated on the substrate surface by means of flexible printing, screen printing, chemical deposition, or other methods to generate flexible temperature, pressure, or gas-sensitive materials with specific sensing functions in situ on the substrate surface.

[0020] Furthermore, the encapsulation layer is formed into a complete plane by surface encapsulation and coating of polydimethylsiloxane, polyimide, or polyethylene terephthalate.

[0021] Compared with the existing solutions described in the background art, the multifunctional component provided by the present invention has the following significant advantages and beneficial effects:

[0022] (1) This invention achieves multi-functional synergy. By integrating heating, multi-parameter sensing, heat insulation and flame retardancy and stress buffering functions into one component, it can not only actively heat the lithium-ion battery, but also collect key parameter information such as temperature, pressure and gas of the lithium-ion battery in real time through the in-situ integrated multi-parameter sensor, so as to realize early warning of safety risks of lithium-ion battery and improve the safety of battery from the source.

[0023] (2) The front and back functional layers of the present invention are arranged in an alternating layout, and the sensors are distributed complementaryly in spatial projection, which saves space and reduces the overall thickness of the components. This layout makes the structure more compact while ensuring multifunctional integration, and can reduce assembly costs and complexity.

[0024] (3) The present invention uses in-situ generation technology to construct functional layers on modified substrates and forms substrate films in-situ on the substrate surface, so that functional layers (sensors, heating wires) and substrates form a strong bond, rather than simple stacking. This greatly improves the stability of the interface bonding between functional layers and substrate layers, and ensures the overall stability, service life and reliability of the multifunctional component.

[0025] (4) The present invention uses heat-insulating and flame-retardant materials as the matrix, so that the component itself has better heat insulation and flame-retardant properties, and can provide a buffer for adjacent batteries when the battery experiences thermal runaway. At the same time, the flexible design allows it to fit well with the battery surface and adapt to the deformation of the battery during charging and discharging, ensuring stable operation under various complex working conditions. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0027] Figure 2 This is an exploded view of the manufacturing process of the present invention;

[0028] Figure 3 This is a front view of the present invention;

[0029] Figure 4 This is a schematic diagram illustrating the specific positional relationship between batteries in which the present invention is applied. Detailed Implementation

[0030] To make the objectives and technical solutions of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

[0031] In the description of this invention, it should be understood that terms such as "bottom," "middle," "inner," and "side," which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements 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. The technical solution of this invention will be described in detail below with reference to the accompanying drawings.

[0032] This invention provides a multifunctional component for safe operation and disaster prevention of lithium-ion batteries, comprising a substrate layer, a functional layer, and an encapsulation layer; such as Figure 1 , Figure 2 and Figure 3 As shown.

[0033] The substrate layer has dimensions of 150mm×120mm×5mm. Polyimide is uniformly grown in situ on the surface of the substrate 1 aerogel felt (density 0.15 g·cm⁻³, thickness 5 mm) using an in-situ generation method, forming a polyimide film on the surface of the aerogel felt, together constituting an integral whole with further surface functionalization.

[0034] The specific preparation process of the polyimide film 6 is as follows: First, the aerogel felt of the substrate 1 is pretreated by drying it in a vacuum at 80°C for 2 hours. After cooling to room temperature, it is stored in a desiccator for later use. Next, the surface treatment solution is prepared by dissolving 3-aminopropyltriethoxysilane (APTES) at 0.5 vol% in a 95 / 5 volume ratio anhydrous ethanol / water mixture, and adjusting the pH to 5 with glacial acetic acid. The pretreated aerogel felt is sprayed or immersed in the above surface treatment solution for 30 seconds, spun dry, and then dried at 80°C for 3 minutes. Immediately after removal, the subsequent polyamic acid coating is performed. Choose a polyamic acid solution with a solid content of 30%-70% (solvent is NMP, DMF or DMSO), apply it by scraping with a gap of 80-120µm, and then perform staged curing in air: 80℃, 30-60min, 120℃, 45-60min, 180℃, 60-90min, 230℃, 90-120min, 260-280℃, 30-60min.

[0035] The dianhydrides in the polyamic acid (PAA) structure are pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 4,4'-oxophthalic dianhydride (ODPA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), 4,4'-(hexafluoroisopropyl)phthalic dianhydride (6FDA), and 4,4'-(4,4'-isopropyldiphenoxy)bis(phthalic anhydride). One of (BPADA); the diamine is one of 4,4'-diaminodiphenyl ether (ODA), 3,4'-diaminodiphenyl ether (3,4'-ODA), p-phenylenediamine (PPD), m-phenylenediamine (MPD), 4,4'-diaminodiphenylmethane (MDA), 1,3-bis(4-aminophenoxy)benzene (TPE-R), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), and bis(3-aminopropyl)-terminated polydimethylsiloxane (AP-PDMS).

[0036] The functional layer includes heating wire 2 and sensor 3, which are staggered in the base layer and do not interfere with each other.

[0037] The heating wire 2 is formed in situ on the surface of the modified substrate 1 using flexible printing, screen printing, chemical deposition, or other methods to create a flexible resistive material with a heat-generating effect in a linear, meandering manner. The heating wire 2 provides a gentle, mild, and uniform heating method for the battery system, effectively compensating for the shortcomings of existing thermal management systems that often suffer from large internal temperature differences and accelerated local aging due to uneven temperature distribution when pursuing rapid heating. This significantly extends the overall cycle life and safety of the battery. A copper-nickel alloy powder slurry with low resistivity (0.49 × 10⁻) is selected as the flexible resistive material. 6 Ω·m. Through optimized design, the printed heating wire, arranged on both sides, has a total length of approximately 2.20 m and a cross-sectional area of ​​3.0 × 10⁻⁻⁻⁶. 7 The calculated total resistance is approximately 3.59 Ω. Under a typical cell voltage of 3.7 V, the heating power is only about 3.81 W, and the energy consumption per hour is about 3.81 Wh, accounting for only 1.03% of the total energy capacity of a 100Ah cell. A 100Ah lithium-ion cell weighs 2 kg and has a specific heat capacity of 1000 J / (kg·K). Calculations show that, without considering heat loss, the battery can heat up by approximately 6.86℃ per hour. In actual operation, a stable temperature rise of 6-7℃ per hour is achieved while maintaining a low energy consumption percentage.

[0038] The sensor 3 is fabricated on the surface of the modified substrate 1 by flexible printing, in situ generating flexible temperature, pressure, or gas-sensitive materials with specific sensing functions on the surface for real-time monitoring of various parameters such as temperature, pressure, and gas. The temperature sensing material is a nickel oxide nanoparticle slurry to achieve accurate sensing of the battery surface temperature; the pressure sensor is a carbon nanotube composite material, whose electrical signals, such as resistance, change with applied pressure to monitor stress changes during battery expansion; and the gas sensing material is SnO2 to achieve early detection of harmful gases.

[0039] The flexible heating wires 2 and sensors 3, printed in situ on the surface of the functionalized substrate 1, are arranged in an alternating pattern without interfering with each other, forming a complete unit that possesses both heating and multi-parameter sensing functions. These functional layers can be formed on one or both sides of the substrate 1 material as needed to control the heating and sensing signals.

[0040] The encapsulation layer 7, after undergoing double-sided printing sensing and temperature heating functions, forms a unified whole. Then, it is encapsulated and coated with polymer materials such as polydimethylsiloxane (PDMS), polyimide (PI), or polyethylene terephthalate (PET) to form a complete plane.

[0041] The invention is further characterized by the front and back sensors being arranged alternately in the spatial projection to form a complementary layout, which makes the overall component thinner, reduces the space, and provides functions such as multi-parameter monitoring, heating, heat insulation and flame retardancy, and support and cushioning.

[0042] like Figure 1 and Figure 4 The multifunctional component 9 of this invention is installed between adjacent batteries 8. Its functional layers are gathered on a flexible circuit board 5 via electrode leads 4, and then connected to the battery tabs via connecting lines 10. The battery itself provides the required power to this multifunctional component. The flexible circuit board 5 and connecting lines 10 feed back the real-time transmitted signals to the battery management system.

[0043] In this embodiment, the battery pack 8 uses square batteries, but is not limited to square batteries; the appropriate type can be selected based on the actual situation.

[0044] In this embodiment, the heating wire 3 is not limited to copper-nickel alloy, but can also be other resistive materials with low resistivity. The length and cross-sectional area of ​​the printed flexible resistive heating wire can be adjusted according to the actual situation to meet the actual needs.

[0045] In this embodiment, the polyimide film 6 is grown uniformly on the surface of the substrate 1 in situ using an in-situ generation method. However, it is not limited to using polyimide. Other materials, such as polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), and other polymer materials, can be selected according to actual conditions and needs.

Claims

1. A multifunctional component for safe operation and disaster prevention of lithium-ion batteries, characterized in that, It includes a base layer, a functional layer, and a packaging layer; The base layer includes a substrate (1), which is an aerogel felt. Polyimide is uniformly grown on the surface of the substrate (1) in an in-situ generation manner, forming a polyimide film (6) on the surface of the aerogel felt. The functional layer includes heating wire (2) and sensor (3), which are arranged alternately on one or both sides of the base layer in spatial projection and do not interfere with each other; An encapsulation layer (7) is formed on the upper surface of the functional layer.

2. A multifunctional component for safe operation and disaster prevention of lithium-ion batteries according to claim 1, characterized in that, The density of the aerogel felt is 0.12-0.18 g·cm⁻³.

3. A multifunctional component for safe operation and disaster prevention of lithium-ion batteries according to claim 1, characterized in that, The method for preparing the polyimide film (6) is as follows: First, the substrate (1) aerogel felt is pretreated by drying it in a vacuum at 80°C for 2 hours. After cooling to room temperature, it is stored in a desiccator for later use. Next, the surface treatment solution was prepared by dissolving 3-aminopropyltriethoxysilane at 0.5 vol% in anhydrous ethanol / water mixed solution with a volume ratio of 95 / 5, and adjusting the pH to 5 with glacial acetic acid. The solution was then sprayed onto the pretreated aerogel felt or immersed in it for 30 seconds, spun dry, and dried at 80°C for 3 minutes. Immediately after removal, proceed with the subsequent polyamic acid coating. Use a polyamic acid solution with a solid content of 30%-70%, apply by scraping with a gap of 80-120µm, and then perform staged curing in air: 80℃, 30-60min, 120℃, 45-60min, 180℃, 60-90min, 230℃, 90-120min, 260-280℃, 30-60min.

4. A multifunctional component for safe operation and disaster prevention of lithium-ion batteries according to claim 3, characterized in that, In the polyamic acid structure described above: The dianhydrides are one of the following: pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxophthalic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 4,4'-(hexafluoroisopropyl)phthalic dianhydride, and 4,4'-(4,4'-isopropyldiphenoxy)bis(phthalic anhydride); The diamine is one of 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylmethane, 1,3-bis(4-aminophenoxy)benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, and bis(3-aminopropyl)-terminated polydimethylsiloxane.

5. A multifunctional component for safe operation and disaster prevention of lithium-ion batteries according to claim 1, characterized in that, The heating wire (2) is formed in situ on the surface of the substrate layer by forming a resistive material with a heat-generating effect in a linear, meandering manner.

6. A multifunctional component for safe operation and disaster prevention of lithium-ion batteries according to claim 1, characterized in that, The sensor (3) is formed in situ on the substrate surface by forming a flexible temperature, pressure or gas sensitive material with specific sensing functions on the substrate surface.

7. A multifunctional component for safe operation and disaster prevention of lithium-ion batteries according to claim 1, characterized in that, The encapsulation layer (7) is formed into a complete plane by surface encapsulation and coating of polydimethylsiloxane, polyimide or polyethylene terephthalate.

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