Power battery connecting line and preparation method thereof

Abstract

The present application relates to the technical field of batteries, and discloses a power battery connecting wire and a preparation method thereof, the power battery connecting wire comprises: a core conductive part composed of a copper-silver alloy and a carbon nanotube composite material, the copper-silver alloy contains copper and silver alloy components, the copper content is 95-99%, and the silver content is 1-5%; the outer layer protection part is composed of polyimide and a carbon fiber reinforced composite material, and the outer layer protection part comprises at least one layer of polyimide material and the carbon fiber reinforced composite material. According to the invention, the core conductive part of the battery connecting wire is made of the copper-silver alloy and carbon nanotube composite material, so that the conductivity and thermal conductivity of the battery connecting wire are remarkably improved. The resistance of the battery connecting wire is effectively reduced by selecting the copper-silver alloy, and the thermal conductivity is enhanced by adding the carbon nanotubes, so that the heat generated in the working process of the battery connecting wire can be quickly led out, and an overheating phenomenon is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a power battery connecting wire and a preparation method thereof. Background Art

[0002] With the rapid development of electric vehicles, energy storage systems, and other high-power battery applications, as one of the key components in the battery system, the performance of the power battery connecting wire is crucial for the safety and stability of the battery system. The connecting wire not only needs to carry a large amount of current, but also generates a large amount of heat during long-term high-load operation, which requires the connecting wire to have excellent electrical conductivity and thermal management capabilities. At the same time, the battery connecting wire also needs to have high strength, good wear resistance, and impact resistance to cope with high-frequency use and changes in the external environment.

[0003] With the continuous progress of battery technology, the requirements for battery connecting wires have gradually increased. To solve the long-term stability problems of battery connecting wires under high current, high temperature, and high mechanical pressure, various solutions have been proposed in the market, including using high-conductive materials, enhancing the mechanical strength of the protective layer, and developing intelligent monitoring systems, etc. However, the existing technical solutions often fail to achieve an ideal balance in these aspects and still have some technical shortcomings.

[0004] Most of the existing battery connecting wires rely on single materials or simple protection structures to cope with current loads and heat management. Although some solutions use metal alloys and composite materials to enhance the electrical conductivity and thermal conductivity of the battery connecting wire, problems such as overheating, aging, and even short circuits may still occur under high-load operation. In addition, traditional battery connecting wires are prone to cracks and damage after mechanical impacts, temperature fluctuations, or long-term use, and these problems often require manual maintenance or replacement, increasing the maintenance cost and complexity of the system.

[0005] Therefore, the existing technology has not effectively solved the reliability problems of battery connecting wires under long-term high loads and harsh environments, especially there are still large deficiencies in preventing overheating, extending service life, and realizing self-repair functions. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the present invention provides a power battery connecting wire and a preparation method thereof, which solve the problems of overheating, damage, and reliability during long-term use of battery connecting wires in the existing technology under high loads and harsh environments, especially the deficiencies of the lack of self-repair functions and intelligent monitoring.

[0007] To achieve the above objectives, the present invention is realized through the following technical solutions: A power battery connecting wire, comprising:

[0008] The core conductive part is composed of a copper-silver alloy and a carbon nanotube composite material, wherein the copper-silver alloy contains alloy components of copper and silver, with a copper content of 95%-99% and a silver content of 1%-5%;

[0009] The outer protective part is composed of polyimide and carbon fiber reinforced composite material, wherein the outer protective part includes at least one layer of polyimide material and carbon fiber reinforced composite material, wherein the volume ratio of the carbon fiber reinforced composite material is 30%-70%, and the volume ratio of the polyimide material is 30%-70%;

[0010] At least one micro heat conduction channel is embedded in the conductive portion of the battery connecting wire and is used to conduct heat from inside the connecting wire.

[0011] Preferably, the outer protective portion of the battery connecting wire further comprises a degradable polylactic acid material, and the mass of the polylactic acid material accounts for 5%-30% of the outer protective portion.

[0012] Preferably, the conductive part of the battery connecting line further comprises at least one nanoparticle material, the nanoparticle material is graphene or silicon nanoparticles, and the mass proportion of the nanoparticles is 5%-15% of the mass of the copper-silver alloy and carbon nanotube composite material.

[0013] Preferably, the thermal conductive channel of the battery connecting wire is a carbon fiber bundle, and the diameter of the carbon fiber bundle is less than 500 μm.

[0014] Preferably, the battery connecting line also includes an embedded temperature sensor and a current sensor, and the sensors are used to monitor the operating temperature and current of the connecting line in real time, transmit data with the battery management system through wireless transmission, and adjust the charging and discharging status of the battery in real time.

[0015] Preferably, the temperature sensor is an NTC thermistor, and the current sensor is a Hall sensor, which can control the battery management system to adjust the battery load when the temperature exceeds a preset threshold.

[0016] A method for preparing a power battery connecting wire comprises the following steps:

[0017] Step (1) preparing a copper-silver alloy and carbon nanotube composite material, mixing the copper-silver alloy and the carbon nanotubes in a predetermined ratio, and performing hot pressing or extrusion molding;

[0018] Step (2) forming a core conductive portion and embedding at least one micro thermal conductive channel therein;

[0019] Step (3) coating the outer layer of the core conductive part with a polyimide material and a carbon fiber reinforced composite material to form an outer protective part;

[0020] Step (4): Coat the surface of the outer protective part with a degradable polylactic acid material and perform a curing treatment;

[0021] Step (5): Conduct an overall inspection of the battery connection wires, including electrical performance testing, thermal stability testing, and self - repair function testing

[0022] Preferably, during the outer coating process in step (3), the volume ratio of the carbon fiber reinforced composite material is 30% - 70%, and the volume ratio of the polyimide is 30% - 70%.

[0023] The present invention provides a power battery connection wire and a preparation method thereof. It has the following beneficial effects:

[0024] 1. By using a copper - silver alloy and carbon nanotube composite material in the core conductive part of the battery connection wire, the present invention significantly improves the electrical conductivity and thermal conductivity of the battery connection wire. The selection of the copper - silver alloy effectively reduces the resistance of the battery connection wire, and the addition of carbon nanotubes enhances the thermal conductivity, which helps to quickly conduct the heat generated during the operation of the battery connection wire and avoid overheating. The battery connection wire can maintain stable operation under long - term high - load working conditions and reduce damage or failures caused by high temperature.

[0025] 2. The outer protective part of the present invention uses a polyimide and carbon fiber reinforced composite material, combined with environmentally friendly materials such as polylactic acid, to ensure that the battery connection wire has excellent mechanical strength, tensile resistance, and impact resistance. The polyimide provides high - temperature electrical insulation protection, while the carbon fiber reinforced composite material enhances the impact resistance and wear resistance of the battery connection wire while providing protection. It ensures that the battery connection wire can adapt to various complex environments, prevent damage caused by external forces or vibrations, and enhance the stability and reliability of the battery system.

[0026] 3. The present invention uses a self - repairing polyurethane material as the outer protective material, which contains a micro - capsule structure. When micro - cracks or damages appear on the surface of the connection wire, the micro - capsules can automatically release the repair liquid to fill the cracks and restore the electrical conductivity and mechanical strength of the connection wire. This self - repair function effectively reduces the performance degradation caused by minor damages, extends the service life of the battery connection wire, and reduces the maintenance cost. This technology provides additional protection for the long - term use of battery connection wires in harsh environments, especially under high load, frequent vibration, or large temperature changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic flow chart of the method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] Please refer to the attached Figure 1 , the embodiments of the present invention provide a power battery connecting wire and its preparation method, including:

[0030] Core conductive part and material selection

[0031] In this embodiment, the core conductive part includes a combination of a copper-silver alloy and a carbon nanotube composite material.

[0032] The design of this composite material is based on a comprehensive consideration of the electrical conductivity and thermal management ability of the battery connecting wire. The copper-silver alloy, as the main conductive material of the battery connecting wire, combines the electrical conductivity of copper and the oxidation resistance of silver, which can effectively reduce the current loss in the connecting wire and improve the durability of the material at the same time. By using it in combination with carbon nanotubes, the thermal conductivity of the conductive part is further improved, enabling heat to be dissipated from the conductive part faster and avoiding overheating problems.

[0033] In specific implementation, the ratio of the copper-silver alloy is between 95% - 99% copper and 1% - 5% silver. The selection of this ratio ensures that the alloy has good electrical conductivity, and the addition of silver improves the corrosion resistance of the alloy. In some embodiments, the electrical conductivity of the copper-silver alloy is generally required to be not less than 60% IACS (International Electrical Conductivity Standard), which can ensure that the current transmission efficiency reaches the expected level.

[0034] Generally, due to its low resistance, the copper-silver alloy is one of the most ideal conductive materials in the battery connecting wire. As an option, the copper-silver alloy can effectively reduce the power loss when a high-load current passes through, thereby improving the overall energy efficiency of the battery system.

[0035] The addition of carbon nanotubes is to further improve the heat dissipation ability of the conductive part. Carbon nanotubes have excellent electrical conductivity and an extremely high specific surface area, which can quickly conduct the heat generated under a large current load. Specifically, the addition of carbon nanotubes not only improves the thermal conductivity of the battery connecting wire but also enhances the mechanical strength of the connecting wire. Due to the nanoscale structure of carbon nanotubes, their surface can further enhance the electrical conductivity through physical and chemical interactions with metal materials, thereby reducing the thermal resistance of the connecting wire.

[0036] The specific surface area of carbon nanotubes can reach 100m 2 / g or more. Through this design, the thermal management ability of the battery connection wire can be effectively improved, enabling the heat generated when current passes through to quickly spread, thus avoiding local overheating caused by heat accumulation.

[0037] In some implementation manners, the combination of the copper-silver alloy and the carbon nanotube composite material adopts a hot pressing or extrusion molding process.

[0038] This process can ensure the uniformity and stability of the material. Through hot pressing or extrusion molding, the copper-silver alloy and the carbon nanotubes can be evenly fused together to form a composite material with good electrical conductivity. Specifically, the extrusion molding technology shapes the material at high temperature, enabling the carbon nanotubes to be evenly distributed in the copper-silver alloy. During this process, the tiny size of the carbon nanotubes enables them to form a tight composite structure with the copper-silver alloy, improving its electrical and thermal conductivity efficiency.

[0039] Specifically, during the preparation process of the composite material of the copper-silver alloy and the carbon nanotubes, the alloy ratio, the dispersion degree of the carbon nanotubes, and the molding temperature need to be strictly controlled.

[0040] During the production process, the dispersion of the carbon nanotubes is a key factor affecting the performance of the composite material. To achieve the best electrical and thermal conductivity, the carbon nanotubes need to be evenly dispersed in the alloy to avoid forming aggregates, which can be achieved through efficient dispersion equipment and technologies. At the same time, the molding temperature of the alloy is controlled between 250°C and 300°C. Too high or too low a temperature will affect the physical properties and chemical bonding of the material. Appropriate temperature and pressure conditions can ensure the stability and excellent performance of the composite material.

[0041] In another embodiment, it is possible to consider adding nanoparticle materials (such as graphene, silicon nanoparticles, etc.) to the composite material of the copper-silver alloy and the carbon nanotubes to further enhance the electrical and thermal conductivity.

[0042] Due to its excellent electrical and thermal conductivity, graphene is often used for the modification of battery connection wires. By adding 1%-5% of graphene to the composite material, the thermal conductivity of the battery connection wire can be significantly improved, ensuring that the heat generated during high-current transmission can be timely exported, preventing material damage caused by overheating. The addition of graphene also improves the mechanical strength of the connection wire and enhances its durability.

[0043] In addition, the optimization of the microstructure is also an important part of the design of the conductive part in this embodiment.

[0044] To further enhance the conductivity, the present invention precisely designs the microstructure of the composite material, enabling the carbon nanotubes and the copper-silver alloy to form a good conductive path at the microscopic level. This design can optimize the internal structure of the material through the Brownian motion model and the electron conduction model, ensuring that electrons can flow freely in the conductive part and reducing the energy loss when the current passes through.

[0045] Specifically, the optimization of electron conduction depends on the interfacial bonding effect between the copper-silver alloy and the carbon nanotubes.

[0046] By optimizing the interfacial treatment method of the copper-silver alloy and the carbon nanotubes, the interfacial resistance can be effectively reduced, and the conductive performance can be improved. Using nanotechnology to chemically modify the surface of the carbon nanotubes to enhance their binding force with the alloy, thereby improving the overall conductive performance of the composite material.

[0047] Through this series of design and process optimizations, the core conductive part of the battery connection line of the present invention can maintain high current transmission efficiency while ensuring effective heat dissipation, avoiding damage problems caused by high temperatures. This technical solution can significantly improve the stability of the battery connection line under high load and long-term use, ensuring the safety and long-term use performance of the power battery system.

[0048] Outer protection part

[0049] The outer protection part plays a crucial role. It is not only responsible for providing necessary electrical insulation to avoid current leakage or short circuit, but also needs to have good mechanical strength to prevent damage caused by external forces. Combining with the aforementioned core conductive part design, the outer protection part needs to ensure heat management ability while effectively supporting the physical durability of the connection line. In this embodiment, the design of the outer protection part considers the stability, heat dissipation ability and environmental friendliness of the battery connection line under long-term high-load operation, and polyimide and carbon fiber reinforced composite materials are selected as the main materials.

[0050] In this embodiment, the design of the outer protection part includes the combination of polyimide (PI) material and carbon fiber reinforced composite material.

[0051] Polyimide is a material with high-temperature stability and electrical insulation, which can remain stable in a high-temperature working environment and will not experience performance degradation due to excessive temperature. Specifically, the heat resistance of polyimide can withstand temperatures exceeding 300 °C, and when used under high load, the temperature of the battery connection line may approach this value. Therefore, choosing polyimide as the inner insulation material of the battery connection line can effectively ensure the safety of the battery connection line. Generally, the thickness of polyimide should be 10 μm to 100 μm to balance electrical insulation and thermal conductivity.

[0052] The outer protective part also incorporates carbon fiber reinforced composite materials. Carbon fiber itself has relatively high mechanical strength and thermal conductivity, which enables the carbon fiber reinforced composite materials to effectively support the connecting wires in high-temperature environments and prevent damage caused by external forces or thermal expansion. The addition of carbon fiber reinforced composite materials can also enhance the impact resistance and tensile resistance of the connecting wires, thereby improving the reliability of the connecting wires during actual operation. Specifically, the volume ratio of carbon fiber in the composite material is usually 30% to 70%, and this ratio can balance the mechanical strength and thermal conductivity, improving the stability of the connecting wires while avoiding excessive weight increase.

[0053] The outer protective part may also include biodegradable polylactic acid (PLA) materials to further improve the environmental performance of the connecting wires. Polylactic acid materials have good biodegradability and can gradually degrade in the natural environment after the end of the usage cycle, without causing persistent pollution to the environment. Specifically, the mass of the polylactic acid material accounts for 5% to 30% of the outer protective part. This design enables the battery connecting wires to be disposed of in a more environmentally friendly manner, meeting the requirements of modern environmental protection materials.

[0054] Specifically, the material coating method of the outer protective part adopts a thermal curing technology and a layer-by-layer coating process.

[0055] First, polyimide and carbon fiber reinforced composite materials are mixed to form a preliminary mixture of the outer protective part. During this process, the ratio of polyimide materials to carbon fiber needs to be optimized according to the required performance requirements. The mixture is uniformly coated on the surface of the core conductive part by an impregnation method or a spin coating method. Then, the coated battery connecting wires are subjected to a high-temperature curing treatment to cure the polyimide materials and carbon fiber reinforced composite materials into one body, ensuring the strength and stability of the protective layer. The curing temperature is usually controlled between 180°C and 220°C, and this temperature range can not only effectively cure the materials but also ensure that the structural stability of the materials is not damaged.

[0056] In some embodiments, after the curing treatment, the outer protective part may also undergo a surface treatment to further improve its corrosion resistance. Through surface treatments such as spraying or electroplating, an additional protective film can be formed on the surface of the outer protective material to prevent chemical substances in the external environment from eroding the materials. Especially in application environments such as electric vehicles and energy storage systems that require high temperature resistance and corrosion resistance, this treatment method can significantly extend the service life of the battery connecting wires.

[0057] Specifically, during the preparation process of the composite material, the mass ratio of the carbon fiber reinforced composite material should be strictly controlled.

[0058] Generally speaking, the mass ratio of carbon fiber should be maintained between 30% and 70%. According to the requirements of different application scenarios, this ratio can be adjusted to achieve the desired mechanical strength and thermal conductivity. For example, in scenarios where high tensile strength is required, the proportion of carbon fiber can be increased; while in cases where strong thermal conductivity is required, the proportion of polyimide can be increased to balance the thermal conductivity and mechanical strength of the composite material.

[0059] For the selection of carbon fiber, the suitable usage method should be determined according to its diameter, length, and type.

[0060] Under normal circumstances, selecting carbon fiber with a smaller diameter can effectively increase the thermal conductivity and mechanical properties of the composite material. During use, the carbon fiber is cut into short lengths or woven so that it is evenly distributed in the polyimide matrix, thereby improving the overall performance of the composite material.

[0061] In some embodiments, the surface coating treatment of the outer protection part can use environmentally friendly coatings.

[0062] This kind of coating can further improve the weather resistance and ultraviolet resistance of the outer protection part, thereby extending the outdoor service life of the battery connection wire. For example, coating a layer of ultraviolet barrier coating can prevent the degradation of materials by ultraviolet rays. Especially in application environments where it is exposed to sunlight for a long time, it can improve the stability and durability of the materials.

[0063] Thermal conduction channels

[0064] The construction of the thermal management channel is a key step to ensure the stable operation of the connection wire under high-load working conditions. The thermal conduction channel not only needs to have excellent thermal conductivity, but also must be closely combined with other parts to ensure that during the current transmission process, the generated heat can be quickly and effectively dissipated to the outside. Combining the design of the core conductive part and the outer protection part in the foregoing steps, the design of the thermal conduction channel should consider the thermal conductivity of the material, the rationality of the structure, and the overall heat dissipation ability. Through careful design and selection of suitable materials, the thermal conduction channel in this embodiment can ensure that the battery connection wire still maintains a good working temperature under high current load.

[0065] In this embodiment, the thermal conduction channel is realized by combining micro carbon fiber bundles with the conductive part.

[0066] This design makes full use of the high thermal conductivity of carbon fiber, embeds it into the conductive part, and forms multiple micro thermal conduction channels. The carbon fiber bundles form channels for heat conduction inside the connection wire, which can effectively guide the heat generated by the core conductive part to the outer protection part. Through this design, heat can be quickly transferred and dispersed, avoiding local overheating, and thus improving the working efficiency and safety of the battery connection wire.

[0067] In actual implementation, the diameter of the carbon fiber bundle is usually controlled within 500 μm to ensure it is small enough to be closely combined with the conductive part, while not having too much impact on the overall volume of the battery connection line. Generally, the length of the carbon fiber bundle should be adjusted accordingly according to the length of the battery connection line and the design of the conductive part to ensure that heat can be evenly dispersed and quickly exported.

[0068] As an option, the carbon fiber bundle in the heat conduction channel can be combined with the conductive material through micro injection molding technology.

[0069] Through injection molding, the carbon fiber bundle and the conductive part can be integrated into one body to ensure the tight combination of the heat conduction channel and the core conductive part, thereby improving the heat conduction efficiency. During the injection molding process, it is crucial to control the dispersion of the alloy and the carbon fiber. The carbon fiber bundle should be evenly distributed in the conductive material to avoid local aggregation, so as to ensure the efficiency and uniformity of the heat conduction channel.

[0070] Specifically, the structural design of the heat conduction channel adopts a micro structure optimization method. During the design, the heat flow path is simulated and optimized by using the heat diffusion equation to ensure that heat can be transferred out through the heat conduction channel to the greatest extent.

[0071] By optimizing the design of the heat conduction channel, the thermal conductivity and cross-sectional area can be effectively increased, thereby improving the conduction efficiency of the heat flow. Specifically, the cross-sectional area of the heat conduction channel is adjusted by changing the distribution density and arrangement of the carbon fiber bundles to ensure that heat can be conducted through the conductive part in the shortest time.

[0072] In a possible implementation, the setting of the heat conduction channel is not limited to the use of carbon fiber bundles, and graphene composites can also be considered to further improve the heat conductivity.

[0073] Graphene, as a material with excellent thermal conductivity, can provide stronger heat dissipation ability in the battery connection line. The addition of graphene can be combined with the carbon fiber bundle to further enhance the heat conduction effect of the heat conduction channel. Specifically, the introduction of graphene can significantly increase the thermal conductivity of the heat conduction channel, enabling the battery connection line to dissipate heat more efficiently under high load conditions.

[0074] Specifically, the composite material of graphene and carbon fiber bundle can be processed by high-energy ball milling to form a uniform composite structure. In this composite material, graphene and the carbon fiber bundle are combined through physical adsorption and chemical cross-linking to form a stable heat conduction network. Through this technical means, it can be ensured that the heat conduction channel has higher thermal conductivity and higher mechanical strength, ensuring that no material fracture or damage occurs during long-term use.

[0075] In some embodiments, in order to ensure the stability of the heat conduction channel and the conductive part, the outer protective part of the connecting wire also adopts a thermal curing treatment technology to enhance the firmness of the overall structure. During the thermal curing process, the carbon fiber bundle and the conductive part can be tightly combined, further improving the stability of the heat conduction channel. Through heating and pressurization, the structure of the heat conduction channel is fully strengthened under the coating of the outer protective material, so as to ensure that the heat conduction effect of the connecting wire will not decrease due to temperature difference and external force during long-term use.

[0076] As another option, the design of the heat conduction channel can also be further enhanced by optimizing the microstructure of the composite material.

[0077] Specifically, by introducing nanoparticles (such as graphene, nanosilicon, etc.), the microstructure of the composite material is optimized, so that the heat conduction channel has better heat conduction ability at the microscale. In this implementation, the nanoparticles are uniformly dispersed in the heat conduction channel as thermal conductivity enhancers, which can significantly improve the heat conduction efficiency.

[0078] Intelligent Monitoring System for Battery Connecting Wires

[0079] The intelligent monitoring system for battery connecting wires is the key to ensuring the safe and stable operation of the connecting wires under long-term high-load working conditions. The intelligent monitoring system can not only monitor the temperature and current of the battery connecting wires in real time, but also automatically adjust the charging and discharging state of the battery according to the monitoring data, so as to effectively avoid potential risks such as overheating and battery damage. Combining with the aforementioned heat conduction channel and composite material design, the system further improves the safety and reliability of the battery connecting wires in actual use by providing real-time feedback.

[0080] In this embodiment, the intelligent monitoring system includes a temperature sensor and a current sensor, which are embedded in key parts of the battery connecting wire to monitor the working state in real time.

[0081] The temperature sensor is mainly used to detect the working temperature of the battery connecting wire, and the current sensor monitors the current intensity. These sensors are connected to the battery management system (BMS) wirelessly to ensure that the sensor data can be fed back to the system in real time for processing. In some embodiments, the NTC thermistor is selected as the temperature sensor, and the Hall sensor is used as the current sensor.

[0082] Generally, the resistance value of the NTC thermistor decreases when the temperature rises, which enables the temperature change to be monitored quickly and accurately. At the same time, due to its non-contact measurement characteristics, the Hall sensor can accurately measure the magnitude of the current, avoiding errors or damages that may be caused by contact sensors.

[0083] As an option, the data acquisition of the temperature sensor and the current sensor is achieved through an analog signal converter.

[0084] The output signals of the temperature sensor and the current sensor are converted into digital signals by an analog-to-digital converter (ADC) for subsequent data processing. The converted data is transmitted to the battery management system (BMS) via a wireless transmission method. The use of wireless transmission technology enables the sensors to avoid direct contact with the battery connection wires, further reducing the complexity and failure rate of the system.

[0085] Specifically, after the BMS system receives the data fed back by the sensors, it analyzes the data through a control algorithm and adjusts the working state of the battery according to the data.

[0086] When the temperature is too high, the BMS can automatically reduce the charging power of the battery or lower the discharge rate to avoid damage to the connection wires due to overheating. In some embodiments, when the temperature exceeds the set threshold, the system will trigger the activation of the cooling system or reduce the generated heat by adjusting the load.

[0087] To precisely control the charge and discharge states of the battery, the BMS adopts a PID control algorithm, where PID represents proportional (P), integral (I), and derivative (D) control. The PID algorithm is corrected based on the real-time data of temperature and current changes to keep the battery connection wires always within the optimal working temperature and current ranges. This control method can quickly respond to temperature changes and ensure that the battery system can still maintain relatively stable performance during high-load operation.

[0088] The BMS protects the battery connection wires by adjusting the load, charging current, or discharge current of the battery.

[0089] In the case of overcharging or over-discharging of the battery system, the BMS can prevent the battery connection wires from overheating, reduce the internal pressure of the battery, and protect the long-term stable operation of the battery by reducing the charging current or stopping the discharge. It can not only ensure the safety of the battery but also extend the service life of the battery and improve the cycle efficiency of the battery.

[0090] Specifically, to enhance the response speed and flexibility of the intelligent monitoring system, the BMS can be connected to a cloud monitoring system to achieve remote monitoring and real-time adjustment.

[0091] By uploading data to the cloud platform, the status of the battery system can be viewed and adjusted in real time anywhere in the world. This remote monitoring technology enables battery management to be no longer limited to local control and can achieve cross-regional and cross-system synchronous adjustment. For example, the overheating alarm of the connection wires can be directly fed back to the management personnel through the cloud system to promptly adjust the system parameters and avoid further damage.

[0092] During the data transmission process, a low-power Bluetooth or Wi-Fi module is adopted. These two technologies can ensure real-time data transmission while consuming less power. In this way, the overall system power consumption can be reduced and the battery working time can be extended.

[0093] To ensure the accuracy of data, the system adopts a redundancy mechanism, that is, temperature and current data are collected by multiple sensors simultaneously and compared. Only when the measured values of all sensors are consistent will the BMS respond. This design avoids possible failures or deviations of a single sensor.

[0094] In some embodiments, the battery management system (BMS) also includes an anomaly detection module that can detect and automatically record any abnormal events of the battery connection line.

[0095] For example, when the temperature sensor detects that the temperature of a certain part continuously exceeds the safety threshold, the system will issue a warning and trigger an alarm mechanism to prevent fires or damages caused by excessive temperature. In the anomaly detection module, a data logging function is adopted to record every anomaly of the battery system, which is convenient for subsequent analysis and troubleshooting.

[0096] In other embodiments, the integration of the temperature and current monitoring system can also consider using multiple communication protocols, such as ZigBee or LoRa.

[0097] These protocols can maintain low power consumption over a long transmission distance while providing sufficient data transmission rate, and are suitable for scenarios that require real-time data transmission. Through these protocols, the real-time data of temperature and current can be transmitted to the central management system or remote server for analysis and processing.

[0098] Self-repair function of the battery connection line

[0099] The self-repair function of the battery connection line is crucial for extending the service life of the connection line and ensuring its long-term stable operation. The self-repair technology can restore its original performance through the repair ability of the material itself when the connection line is slightly damaged, avoiding greater failures caused by small-scale damages. This function is especially applicable to high-load working environments where the battery connection line is often affected by external factors such as temperature fluctuations and vibrations. Combined with the previously designed conductive part, protective layer and intelligent monitoring system, the self-repair technology can not only improve the service life of the battery connection line, but also effectively reduce the system maintenance cost.

[0100] In this embodiment, the self-healing function of the battery connection line is realized by using self-healing polyurethane (PU) material, which is characterized by having built-in microcapsules filled with repair fluid. When the self-healing polyurethane is damaged by external force, the microcapsules rupture, and the repair fluid is released and fills the cracks or damaged parts through chemical reactions, restoring the mechanical strength and electrical performance of the material. This design enables the battery connection line to maintain a stable working state even when minor damages occur during long-term use.

[0101] Specifically, the repair fluid fills the cracks through the mechanism of reversible cross-linking reaction. When external stress or temperature changes cause microcracks on the surface of the battery connection line, the repair fluid can quickly fill the cracks and restore the structural integrity at the crack. Specifically, the chemical composition of the repair fluid includes diisocyanate and hydroxyl compounds, which react under the high-temperature environment of the crack to generate tough polyurethane chains to fill the cracks. This process can be triggered by external temperature or stress, so the battery connection line can automatically repair according to the usage environment.

[0102] In some embodiments, the microcapsules of the self-healing polyurethane are prepared by spray drying method. This method can ensure the uniform distribution of the repair fluid in the polyurethane material, so that when cracks appear, the microcapsules can quickly rupture and release the repair fluid. The core of this process is the uniformity and distribution of the microcapsules. By optimizing the spray drying process, the size and distribution of the microcapsules can be within the optimal range, improving the repair efficiency. In certain embodiments, the average diameter range of the microcapsules can be controlled between 100μm and 500μm to ensure their adaptation to cracks of different sizes.

[0103] In another possible implementation, the microcapsules of the polyurethane self-healing material can be customized according to the usage requirements of the connection line.

[0104] For example, in a high-temperature environment, the microcapsules can be designed with a polymer shell having a relatively high melting point, so that the stable repair function can still be maintained under high-temperature working conditions. At the same time, by changing the ratio and chemical composition of the repair fluid, different types of damages (such as fracturing or microcracks) can be optimized to ensure the comprehensiveness of the repair effect.

[0105] Specifically, the performance of the repair fluid can be expressed by the following formula:

[0106] R = α·T·ΔP

[0107] Wherein, R represents the repair effect, α is the reaction rate constant of the repair material, T is the environmental temperature, and ΔP is the stress change at the crack. This formula shows that temperature and stress changes are the key factors affecting the repair effect. Therefore, the changes in temperature and stress can trigger the chemical reaction of the repair fluid to achieve the purpose of repairing cracks.

[0108] In some embodiments, the repair fluid in the microcapsules is not limited to a single component and can also contain a catalyst or a filler, which can accelerate the repair reaction or provide additional strength support. The addition of a catalyst can accelerate the polymerization reaction of the repair fluid, making the repair process more efficient; while the use of a filler can increase the mechanical strength of the repaired material and enhance its resistance to external impacts.

[0109] The repair fluid can also form a high-strength cross-linked network structure through chemical cross-linking reactions. This structure not only increases the mechanical properties of the repaired part but also improves its tolerance to high temperatures and stresses. The cross-linking reaction enables the repair material to form a stable three-dimensional network structure, which can effectively connect the materials on both sides of the crack and enhance the overall tensile and compressive strengths.

[0110] The self-healing polyurethane material of the present invention can also be used in combination with other materials, such as graphene or carbon nanotubes, etc., to improve its thermal conductivity and mechanical strength. Graphene and carbon nanotubes, as thermal conductive materials added to the self-healing material, can help dissipate heat quickly and prevent a new round of damage caused by excessive temperatures. Specifically, adding 2%-10% of graphene or carbon nanotubes to the self-healing polyurethane helps quickly conduct heat away from the repair area and avoid poor repair effects or material degradation caused by overheating.

[0111] In this embodiment, the preparation process of the composite material ensures its stability through high-temperature curing treatment. This process not only enhances the mechanical properties of the composite material but also ensures the continuous stability of the self-healing function in a high-load working environment. The high-temperature curing treatment is usually controlled between 200°C and 250°C to ensure that the repair fluid can be fully cross-linked to form a solid structure.

[0112] In addition, to ensure the long-term stability of the self-healing material, the self-healing polyurethane in the present invention has also undergone aging tests and environmental adaptability tests. These tests include aging tests under extreme environments such as exposure to high temperatures, humidity, and ultraviolet rays to ensure that the material can still maintain good repair performance under different environmental conditions.

[0113] Example 1: Battery connection wires for electric vehicle power battery systems

[0114] Background: In the power battery system of an electric vehicle, the battery connection wires need to carry a high current and generate a large amount of heat during the charging and discharging processes. The battery connection wires work under high-temperature and high-current load conditions for a long time, so high requirements are placed on their electrical conductivity, thermal management ability, and safety.

[0115] This embodiment adopts the battery connection line of the present invention and its preparation method, and is designed according to the application requirements in the power battery system of electric vehicles.

[0116] Material selection: The core conductive part of the battery connection line uses a copper-silver alloy and carbon nanotube composite material. The copper content of the copper-silver alloy is 97%, and the silver content is 3%. This ratio can ensure that the battery connection line has excellent electrical conductivity, and the addition of silver effectively improves the oxidation resistance of the alloy, adapting to the frequent high-load operation in the electric vehicle battery system. The specific surface area of the carbon nanotube composite material is 100m 2 / g, enhancing the electrical conductivity and heat dissipation ability, and ensuring that the battery connection line maintains a low temperature rise under long-term high-current operation.

[0117] Outer layer protection: The outer layer protection part of the battery connection line is composed of polyimide (PI) and carbon fiber reinforced composite material. The high temperature resistance of the polyimide material can withstand the common high temperature environment during the operation of electric vehicle batteries, while the carbon fiber composite material provides strong tensile and impact resistance, effectively protecting the connection line from damage caused by vibration or collision during vehicle driving.

[0118] Thermal management design: The micro thermal conduction channel of the battery connection line adopts a carbon fiber bundle design, and the diameter of the carbon fiber bundle is 200μm. Through the micro thermal conduction channel, the battery connection line can quickly transfer the generated heat to the outside, preventing the connection line from aging or being damaged due to excessive temperature. This design effectively reduces the heat accumulation problem caused by high-load operation in the electric vehicle battery system.

[0119] Self-healing function: The outer layer protection part uses a self-healing polyurethane (PU) material. When the connection line has minor cracks due to overheating or mechanical collision, the repair liquid in the microcapsules can be automatically released and fill the cracks through chemical reactions, restoring the electrical conductivity and electrical performance of the material, thereby extending the service life of the battery connection line.

[0120] Applicable scenarios: This embodiment is applicable to the power battery system of electric vehicles, especially under the working conditions of high-speed charging, long-term large-current discharging, and frequent vibration. The self-healing function and excellent thermal management ability ensure the long-term stable operation of the connection line.

[0121] Embodiment 2: Battery connection line for energy storage system

[0122] Background: In an energy storage system, the battery connection line needs to work stably for a long time and is often in a high-current and high-power working environment. Since the batteries in the energy storage system are usually installed outdoors or in different climate environments, the reliability, corrosion resistance, and environmental adaptability of the battery connection line are crucial.

[0123] The battery connection line designed in this embodiment is specifically for providing high reliability and high efficiency in battery connection in energy storage systems.

[0124] Material selection: The core conductive part of the connection line uses a copper-silver alloy and carbon nanotube composite material. The copper content of the copper-silver alloy is 96% and the silver content is 4%, which can ensure good electrical conductivity and high oxidation resistance, meeting the requirements of long-term use in energy storage systems. The addition of carbon nanotubes further enhances the heat dissipation ability of the conductive part, enabling it to operate at low temperatures under high loads.

[0125] Outer layer protection: The outer layer protection part is composed of polylactic acid (PLA) and carbon fiber reinforced composite material. The polylactic acid material meets environmental protection standards and can be biodegradable after the end of its service life, reducing environmental pollution. The carbon fiber reinforced composite material provides good impact resistance and tensile strength, protecting the connection line from damage under external pressure and adapting to the common outdoor use environment of energy storage systems.

[0126] Thermal management: The thermal conduction channel of the battery connection line uses a graphene composite material. Graphene has extremely high thermal conductivity, which can efficiently conduct the heat generated by the battery connection line, ensuring that the temperature of the connection line remains within a safe range during high-load operation. The use of graphene composite material enables the battery connection line to have stronger heat dissipation ability, reducing the risk of damage caused by overheating.

[0127] Self-healing function: Self-healing polyurethane material is used. When the connection line is damaged externally during transportation or long-term use, the repair liquid in the microcapsules will be automatically released to fill the damaged part. The self-healing function ensures that the connection line can automatically recover when encountering minor damage, extending the service life of the connection line and reducing maintenance costs.

[0128] Applicable scenarios: This embodiment is applicable to energy storage systems, especially suitable for outdoor energy storage devices, wind energy and solar energy storage systems. The battery connection line needs to work stably for a long time and be able to adapt to changing environmental conditions, such as high humidity, high temperature or cold regions.

[0129] Embodiment 3: Battery connection line for household energy storage battery system

[0130] Background: Household energy storage battery systems usually require battery connection lines to operate stably for a long time in the home environment, with relatively low current loads, but still need to ensure that the connection lines do not overheat or malfunction during high-frequency use. At the same time, the environmental protection and safety of materials need to be considered in household energy storage systems.

[0131] The battery connection line in this embodiment is specifically designed for household energy storage battery systems, with a focus on its stability, environmental protection and safety in the home use environment.

[0132] Material Selection: The core conductive part of the connecting wire uses a copper-silver alloy and carbon nanotube composite material. The copper content of the copper-silver alloy is 98% and the silver content is 2%. This ratio ensures that the connecting wire has a lower resistance and better oxidation resistance, and can stably transmit current in a household energy storage system. The addition of the carbon nanotube composite material improves the thermal conductivity of the connecting wire, helps the connecting wire maintain a low temperature during long-term operation, and reduces performance degradation caused by overheating.

[0133] Outer Protection: The outer protection part uses polyimide (PI) and biodegradable polylactic acid (PLA) materials. Polyimide provides electrical insulation performance at high temperatures, while PLA materials can be biodegradable at the end of their service life, meeting environmental protection standards. This material combination not only ensures the performance of the connecting wire but also improves its environmental friendliness, making it suitable for household energy storage systems.

[0134] The heat conduction channel of the battery connecting wire adopts a carbon fiber bundle design, and the diameter of the carbon fiber bundle is controlled at 300 μm. This design can effectively conduct the heat generated by the battery connecting wire, avoiding the aging or damage of the connecting wire caused by excessive temperature. Through the combination with the conductive part, the heat conduction channel can quickly take away heat under high current loads.

[0135] The outer protection part uses self-healing polyurethane (PU) material with a microcapsule structure. When the connecting wire is slightly damaged, the repair liquid is automatically released and fills the crack through a chemical reaction to restore the integrity of the connecting wire. This self-healing function not only extends the service life of the battery connecting wire but also reduces the maintenance requirements of the system.

[0136] Applicable Scenarios: This embodiment is particularly applicable to household energy storage battery systems, can operate stably in a household environment for a long time, and at the same time has strong environmental friendliness and safety, meeting the low-maintenance and high-reliability requirements of household users for battery systems.

[0137] Table 1: Comparison table of experimental data of the embodiment.

[0138]

[0139] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A power battery connecting wire, characterized in that: include: The core conductive part is composed of a copper-silver alloy and a carbon nanotube composite material, wherein the copper-silver alloy contains alloy components of copper and silver, with a copper content of 95%-99% and a silver content of 1%-5%; The outer protective part is composed of polyimide and carbon fiber reinforced composite material, wherein the outer protective part includes at least one layer of polyimide material and carbon fiber reinforced composite material, wherein the volume ratio of the carbon fiber reinforced composite material is 30%-70%, and the volume ratio of the polyimide material is 30%-70%; At least one micro heat conduction channel is embedded in the conductive portion of the battery connecting wire and is used to conduct heat from inside the connecting wire.

2. A power battery connecting wire according to claim 1, characterized in that: The outer protective portion of the battery connecting wire also includes a degradable polylactic acid material, and the mass of the polylactic acid material accounts for 5%-30% of the outer protective portion.

3. A power battery connecting wire according to claim 1, characterized in that: The conductive part of the battery connecting line also includes at least one nanoparticle material, the nanoparticle material is graphene or silicon nanoparticles, and the mass proportion of the nanoparticles is 5%-15% of the mass of the copper-silver alloy and carbon nanotube composite material.

4. A power battery connecting wire according to claim 1, characterized in that: The thermal conductive channel of the battery connecting wire is a carbon fiber bundle, and the diameter of the carbon fiber bundle is less than 500 μm.

5. A power battery connecting wire according to claim 1, characterized in that: The battery connecting line also includes an embedded temperature sensor and a current sensor, which are used to monitor the operating temperature and current of the connecting line in real time, transmit data with the battery management system through wireless transmission, and adjust the charging and discharging status of the battery in real time.

6. A power battery connecting wire according to claim 5, characterized in that: The temperature sensor is an NTC thermistor, and the current sensor is a Hall sensor, which can control the battery management system to adjust the battery load when the temperature exceeds a preset threshold.

7. A method for preparing a power battery connecting wire, according to a power battery connecting wire according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step (1) preparing a copper-silver alloy and carbon nanotube composite material, mixing the copper-silver alloy and the carbon nanotubes in a predetermined ratio, and performing hot pressing or extrusion molding; Step (2) forming a core conductive portion and embedding at least one micro thermal conductive channel therein; Step (3) coating the outer layer of the core conductive part with a polyimide material and a carbon fiber reinforced composite material to form an outer protective part; Step (4) coating the surface of the outer protective portion with a degradable polylactic acid material and performing a curing treatment; Step (5) performs an overall inspection on the battery connection line, including an electrical performance test, a thermal stability test, and a self-repair function test.

8. A method for preparing a power battery connecting wire according to claim 7, characterized in that: During the outer layer coating process in step (3), the volume ratio of the carbon fiber reinforced composite material is 30%-70%, and the volume ratio of the polyimide is 30%-70%.

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