Manufacturing method of flexible secondary battery

Abstract

The invention discloses a manufacturing method of a flexible secondary battery, which comprises the following steps: S1, taking an aluminum wire with the diameter of 50-500 microns as a positive current collector, and taking a copper wire with the diameter of 50-500 microns as a negative current collector; s2, uniformly coating the surface of the aluminum wire with a positive electrode material coating with the thickness of 5-30 [mu] m, and uniformly coating the surface of the copper wire with a negative electrode material coating with the thickness of 5-30 [mu] m; s3, covering a layer of aramid fiber porous isolating membrane with the porosity of 5-40% outside the positive electrode material coating of the aluminum wire; and S4, twisting and compounding the copper wire treated in the step S2 and the aluminum wire treated in the step S3 through a twisting process, so that the positive electrode material coating, the aramid fiber porous isolating membrane and the negative electrode material coating are in close contact to form the flexible battery wire. The coating uniformity is optimized, and the binding force of the current collector and the electrode material is improved, so that the high performance and the stability of the battery are ensured.

Description

Technical Field

[0001] The invention relates to a battery manufacturing method and belongs to the technical field of batteries. Background Art

[0002] With the popularity of wearable devices and portable electronic products, the demand for flexible batteries is increasing. Traditional batteries are difficult to adapt to the needs of these application scenarios due to rigid structural limitations. However, how to improve the energy density, cycle stability and durability of batteries is still an important problem that needs to be solved in current technology.

[0003] A Chinese patent with publication number CN112164828A discloses a method for preparing a flexible aluminum ion battery, using graphene fiber as a positive electrode, and aluminum wire and glass fiber filter paper as a negative electrode and a separator, respectively, to prepare a fibrous flexible aluminum ion battery. Summary of the invention

[0004] In view of the above-mentioned defects of the prior art, the task of the present invention is to provide a method for manufacturing a flexible secondary battery, with the aim of simplifying the battery preparation process, optimizing the coating uniformity, and improving the bonding strength between the current collector and the electrode material to ensure the high performance and stability of the battery.

[0005] The technical solution of the present invention is as follows: A method for manufacturing a flexible secondary battery comprises the following steps:

[0006] S1, using an aluminum wire with a diameter of 50 to 500 μm as a positive electrode current collector, and using a copper wire with a diameter of 50 to 500 μm as a positive electrode current collector;

[0007] S2. Evenly apply a positive electrode material coating with a thickness of 5 to 30 μm on the surface of the aluminum wire, and evenly apply a negative electrode material coating with a thickness of 5 to 30 μm on the surface of the copper wire;

[0008] S3, covering the positive electrode material coating of the aluminum wire with a layer of aramid porous separator with a porosity of 5% to 40%;

[0009] S4. The copper wire processed in step S2 and the aluminum wire processed in step S3 are twisted and compounded by a twisting process, so that the positive electrode material coating, the aramid porous isolation membrane and the negative electrode material coating are in close contact to form a flexible battery wire.

[0010] Furthermore, in order to improve the mechanical strength and electrical conductivity of the battery wire, the diameter of the aluminum wire is 100 to 300 μm, and the diameter of the copper wire is 100 to 300 μm.

[0011] The aluminum wire within this diameter range is used as the positive electrode current collector, which not only provides sufficient mechanical strength to support the positive electrode material layer and prevent deformation or breakage that may occur during battery manufacturing and use, but its good electrical conductivity ensures that the current can be efficiently and smoothly transmitted inside the battery, reducing the internal resistance and improving the overall performance of the battery. Similarly, the copper wire, used as the negative electrode current collector, also exhibits excellent mechanical strength and conductivity within this diameter range. It can not only firmly support the negative electrode material layer and prevent the material from falling off or stratification, but also ensure that the negative electrode maintains a stable current output during the charge and discharge process, further improving the battery's cycle stability and service life.

[0012] Furthermore, the positive electrode material coating is lithium iron phosphate or sodium positive electrode material, and the negative electrode material coating is graphite negative electrode material.

[0013] Furthermore, the thickness of the positive electrode material coating is 15-20 μm, and the thickness of the negative electrode material coating is 15-20 μm. This enables the battery to store more energy, while optimizing the charge and discharge efficiency, ensuring that the battery can maintain stable performance output during rapid charge and discharge, which not only enhances the energy density and power density of the battery, but also prolongs the battery life.

[0014] Furthermore, in the step S2, a scraping process is used when applying the positive electrode material and the negative electrode material. Scraping the positive electrode material improves the uniformity of the positive electrode material layer, ensures that the active material of each part can fully play its role, thereby optimizing the electrochemical performance of the battery, greatly enhancing the adhesion between the positive electrode material layer and the current collector, effectively preventing the material shedding problem that may occur during the battery charge and discharge cycle, and improving the durability and reliability of the battery wire. Scraping the negative electrode material ensures the high uniformity of the negative electrode material layer, so that the battery can maintain a stable current output during the charge and discharge process, thereby improving the overall performance of the battery, and significantly enhancing the adhesion between the negative electrode material layer and the copper wire current collector, effectively avoiding the battery performance degradation or failure caused by material shedding, and extending the service life of the battery.

[0015] Furthermore, in order to optimize the migration speed of ions and the charge and discharge performance of the battery, the porosity of the aramid porous separator is 10% to 30%.

[0016] The porosity of the aramid porous isolation membrane is controlled at 10% to 30%, which significantly improves the migration speed of ions and enables the battery to respond to current demands more quickly during the charging and discharging process, thereby improving the power density and charging and discharging efficiency of the battery. Moreover, through reasonable pore structure design, it effectively balances the rapid transmission of ions and the safety performance inside the battery, ensuring that the battery can still maintain stability and safety during high-speed charging and discharging.

[0017] Furthermore, the temperature of the twisting process in step S4 is controlled at room temperature to 60° C., and the contact pressure between the aluminum wire and the copper wire is 0.1 to 0.5 MPa.

[0018] The use of this process parameter can effectively promote close contact between the positive and negative electrodes and the isolation membrane, reduce internal resistance, and improve the conductivity of the battery wire; it also ensures that the battery wire maintains good structural stability during the molding process, avoiding material deformation or damage caused by excessive temperature or pressure, thereby significantly improving the overall mechanical strength and durability of the battery wire.

[0019] Furthermore, before applying the positive electrode material coating on the surface of the aluminum wire and applying the negative electrode material coating on the surface of the copper wire, the aluminum wire and the copper wire are surface treated, and the surface treatment includes cleaning, activation and pre-coating treatment to enhance the adhesion and conductivity of the positive electrode material and the negative electrode material.

[0020] First, the cleaning step can thoroughly remove impurities such as dirt, grease and oxides on the surface of the metal wire, laying a good foundation for the subsequent activation and pre-coating treatment, ensuring the stability and consistency of the treatment effect. Secondly, the activation step improves the activity of the metal wire surface through chemical or physical methods, making it easier to form a good chemical bond with the positive or negative electrode material, thereby enhancing the bonding and adhesion between the two. Finally, the pre-coating treatment forms a thin transition layer on the surface of the metal wire, which can not only further increase the bonding strength, but also optimize the interface performance between the metal wire and the active material, reduce the interface resistance, and improve the electrochemical performance and cycle stability of the battery.

[0021] Furthermore, after the flexible battery filament is prepared, battery formation and testing are performed, and the battery formation and testing include constant current charging and constant voltage charging processes, which are used to activate battery materials and improve battery performance and safety.

[0022] This process can effectively activate the internal materials of the battery and ensure that the active substances in the battery fully react, thereby improving the performance of the battery, including energy density, power density and cycle life. At the same time, through strict monitoring and testing during the formation process, potential safety hazards can be discovered and eliminated in a timely manner, ensuring the safety and reliability of the battery during use.

[0023] The advantages of the present invention compared with the prior art are:

[0024] 1. The flexible battery wire made by the present invention has a 180° bending ability and can maintain stable electrochemical performance after repeated bending, and the electrochemical performance includes but is not limited to capacity retention rate, internal resistance change and cycle life. It can broaden the application scenarios of flexible batteries, enabling them to adapt to various complex and changeable geometric forms and space constraints, while also ensuring the efficiency, safety and reliability of the battery during long-term use, providing strong support for the development of flexible electronic devices, wearable technology and portable energy solutions.

[0025] 2. The present invention ensures that the flexible secondary battery has good bending performance while maintaining the stability of its electrochemical properties by precisely controlling the coating thickness of each material, the porosity of the isolation membrane and the key parameters of the twisting process. By optimizing the distribution of the coating thickness, the phenomenon of the battery material being too thin or too thick is avoided, and the full reaction of the material and the stable electrochemical properties are ensured. The precise control of the porosity of the isolation membrane maximizes the ionic conductivity of the battery, reduces the internal resistance, and improves the charging and discharging efficiency. At the same time, the optimization of the twisting process effectively avoids structural damage or battery performance degradation caused by repeated bending and stretching, and can still maintain good capacity and internal resistance performance under a long-term dynamic environment, ensuring its long-term stable service life.

[0026] 3. The present invention improves the charge and discharge efficiency and cycle stability of the battery by coating the positive electrode material coating and the negative electrode material coating on the surface of the aluminum wire and the copper wire through a scraping process. At the same time, an efficient surface treatment process is introduced to enhance the bonding force between the current collector and the electrode material, ensuring smoother current transmission inside the battery, thereby improving the overall performance, service life and stability of the battery. Through these improved production processes, not only the consistency of the high performance of the battery is guaranteed, but also the production efficiency is significantly improved.

[0027] 4. The present invention controls the porosity of the aramid porous isolation membrane to be between 10% and 30%, effectively balancing the ionic conductivity and electrolyte stability, avoiding the problem of excessive internal resistance caused by too low porosity, or electrolyte instability caused by too high porosity, so that the battery can not only maintain a low internal resistance during long-term charge and discharge, but also maintain a stable electrolyte environment, thereby improving the cycle stability and service life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the process of manufacturing a flexible secondary battery of an embodiment. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the embodiments, but are not intended to limit the present invention.

[0030] Example 1, please combine Figure 1As shown, a method for manufacturing a flexible secondary battery, the method comprising:

[0031] S1, preparation stage: prepare aluminum wire with a diameter of 50 μm as the positive electrode current collector and copper wire with a diameter of 50 μm as the negative electrode current collector to improve the mechanical strength and conductivity of the battery wire; before proceeding to the next stage of processing, the aluminum wire and the copper wire are surface treated, and the surface treatment includes cleaning, activation and pre-coating. The cleaning step can be wiped or soaked with a solvent (such as ethanol, acetone, etc.) to completely remove impurities such as dirt, grease and oxides on the surface of the metal wire. Activation is to improve the activity of the metal wire surface by chemical or physical methods, such as acidic solution (such as dilute hydrochloric acid or nitric acid) pickling. The pre-coating treatment forms a transition layer on the surface of the metal wire, wherein the pre-coating treatment can be applied by solution coating, sputtering, electrochemical deposition or chemical vapor deposition. Commonly used coating materials include conductive polymers (such as polyaniline, polypyrrole), metal coatings (such as copper, nickel, titanium) and conductive carbon materials (such as carbon nanotubes, graphene). In this embodiment, the transition layer is 0.5 μm polypyrrole.

[0032] S2, positive electrode material coating stage and negative electrode material coating stage: a layer of positive electrode material coating is evenly coated on the aluminum wire by a scraping process. The positive electrode material is lithium iron phosphate and the coating thickness is 5μm to ensure the electrochemical performance of the battery; a layer of negative electrode material is evenly coated on the copper wire by a scraping process. The negative electrode material is graphite and the coating thickness is 5μm to improve the charge and discharge efficiency of the battery.

[0033] S4, isolation membrane covering stage: A layer of aramid porous isolation membrane with a porosity of 5% is covered on the outside of the positive electrode material coating of the aluminum wire to achieve rapid ion transmission and battery safety performance.

[0034] S5, assembly and molding stage: The positive and negative electrodes and the isolation membrane are brought into close contact through a twisting process to form a flexible battery wire. During the twisting process, the temperature is controlled at 30°C and the contact pressure between the aluminum wire and the copper wire is 0.1Mpa.

[0035] It is used to improve the structural integrity and electrical contact performance of battery wires. The twisting process includes stacking the positive electrode, negative electrode and separator in order, and making them in close contact by rotating or bending to ensure good contact between the positive and negative electrodes and the separator. This process requires controlling the twisting angle and strength to avoid damaging the material and ensure the tightness and stability of the battery structure. Finally, it is shaped by heating or cooling to ensure that the battery can still work normally when bent or deformed.

[0036] After assembly, the flexible battery wire is subjected to battery formation and testing. The battery formation and testing include constant current charging and constant voltage charging processes. First, constant current charging is performed, usually using a smaller current (such as 0.1C to 0.5C) to charge the battery until the battery voltage reaches a predetermined constant voltage value (such as 4.2V). Then, the constant voltage charging stage is entered, the voltage is kept unchanged, and the charging current is gradually reduced until the charging current drops to the set termination value (such as 0.01C).

[0037] Embodiment 2, a method for manufacturing a flexible secondary battery, the method comprising:

[0038] S1, preparation stage: prepare aluminum wire with a diameter of 100μm as the positive electrode current collector and copper wire with a diameter of 100μm as the negative electrode current collector to improve the mechanical strength and conductivity of the battery wire; before proceeding to the next stage of processing, the aluminum wire and copper wire are surface treated, and the surface treatment includes cleaning, activation and pre-coating. The purpose of the cleaning step is to thoroughly remove impurities such as dirt, grease and oxides on the surface of the metal wire. The activation is to increase the activity of the metal wire surface by chemical or physical methods. The pre-coating treatment forms a 0.5μm polypyrrole transition layer on the surface of the metal wire.

[0039] S2, positive electrode material coating stage and negative electrode material coating stage: a layer of positive electrode material coating is evenly coated on the aluminum wire by a scraping process. The positive electrode material is lithium iron phosphate and the coating thickness is 10μm to ensure the electrochemical performance of the battery; a layer of negative electrode material is evenly coated on the copper wire by a scraping process. The negative electrode material is graphite and the coating thickness is 10μm to improve the charging and discharging efficiency of the battery.

[0040] S4, separator covering stage: a layer of aramid porous separator with a porosity of 10% is covered on the positive electrode material coating of the aluminum wire to achieve rapid ion transmission and battery safety performance;

[0041] S5, assembly and molding stage: The positive and negative electrodes and the isolation membrane are brought into close contact through a twisting process to form a flexible battery wire. During the twisting process, the temperature is controlled at 35°C and the contact pressure between the aluminum wire and the copper wire is 0.2MPa to improve the structural integrity and electrical contact performance of the battery wire. After assembly, the flexible battery wire is subjected to the same battery formation and testing as in Example 1.

[0042] Embodiment 3, a method for manufacturing a flexible secondary battery, the method comprising:

[0043] S1, preparation stage: prepare aluminum wire with a diameter of 200μm as the positive electrode current collector and copper wire with a diameter of 200μm as the negative electrode current collector to improve the mechanical strength and conductivity of the battery wire; before proceeding to the next stage of processing, the aluminum wire and copper wire are surface treated, and the surface treatment includes cleaning, activation and pre-coating. The purpose of the cleaning step is to thoroughly remove impurities such as dirt, grease and oxides on the surface of the metal wire. Activation is to increase the activity of the metal wire surface by chemical or physical methods. The pre-coating treatment forms a thin transition layer on the surface of the metal wire.

[0044] S2, positive electrode material coating stage and negative electrode material coating stage: a layer of positive electrode material coating is evenly coated on the aluminum wire by a scraping process. The positive electrode material is lithium iron phosphate and the coating thickness is 15μm to ensure the electrochemical performance of the battery; a layer of negative electrode material is evenly coated on the copper wire by a scraping process. The negative electrode material is graphite and the coating thickness is 15μm to improve the charge and discharge efficiency of the battery.

[0045] S4, separator covering stage: a layer of aramid porous separator with a porosity of 20% is covered on the positive electrode material coating of the aluminum wire to achieve rapid ion transmission and battery safety performance;

[0046] S5, assembly and molding stage: The positive and negative electrodes and the separator are closely contacted by a twisting process to form a flexible battery wire. During the twisting process, the temperature is controlled to be 35°C and the contact pressure between the aluminum wire and the copper wire is 0.3MPa to improve the structural integrity and electrical contact performance of the battery wire. After the assembly is completed, the flexible battery wire is subjected to the same battery formation and testing as in Example 1.

[0047] Embodiment 4, a method for manufacturing a flexible secondary battery, the method comprising:

[0048] S1, preparation stage: prepare aluminum wire with a diameter of 300μm as the positive electrode current collector and copper wire with a diameter of 300μm as the negative electrode current collector to improve the mechanical strength and conductivity of the battery wire; before proceeding to the next stage of processing, the aluminum wire and copper wire are surface treated, and the surface treatment includes cleaning, activation and pre-coating. The purpose of the cleaning step is to thoroughly remove impurities such as dirt, grease and oxides on the surface of the metal wire. The activation is to increase the activity of the metal wire surface by chemical or physical methods. The pre-coating treatment forms a 0.5μm polypyrrole transition layer on the surface of the metal wire.

[0049] S2, positive electrode material coating stage and negative electrode material coating stage: a layer of positive electrode material coating is evenly coated on the aluminum wire by a scraping process. The positive electrode material is lithium iron phosphate and the coating thickness is 20μm to ensure the electrochemical performance of the battery; a layer of negative electrode material is evenly coated on the copper wire by a scraping process. The negative electrode material is graphite and the coating thickness is 20μm to improve the charging and discharging efficiency of the battery.

[0050] S4, separator covering stage: a layer of aramid porous separator with a porosity of 30% is covered on the positive electrode material coating of the aluminum wire to achieve rapid ion transmission and battery safety performance;

[0051] S5, assembly and forming stage: The positive and negative electrodes and the separator are closely contacted by a twisting process to form a flexible battery wire. During the twisting process, the temperature is controlled to be 40°C and the contact pressure between the aluminum wire and the copper wire is 0.3MPa to improve the structural integrity and electrical contact performance of the battery wire. After the assembly is completed, the flexible battery wire is subjected to the same battery formation and testing as in Example 1.

[0052] Embodiment 5, a method for manufacturing a flexible secondary battery, the method comprising:

[0053] S1, preparation stage: prepare aluminum wire with a diameter of 500μm as the positive electrode current collector and copper wire with a diameter of 500μm as the negative electrode current collector to improve the mechanical strength and conductivity of the battery wire; before proceeding to the next stage of processing, the aluminum wire and copper wire are surface treated, and the surface treatment includes cleaning, activation and pre-coating. The purpose of the cleaning step is to thoroughly remove impurities such as dirt, grease and oxides on the surface of the metal wire. The activation is to increase the activity of the metal wire surface by chemical or physical methods. The pre-coating treatment forms a 0.5μm polypyrrole transition layer on the surface of the metal wire.

[0054] S2, positive electrode material coating stage and negative electrode material coating stage: a layer of positive electrode material coating is evenly coated on the aluminum wire by a scraping process. The positive electrode material is lithium iron phosphate and the coating thickness is 30μm to ensure the electrochemical performance of the battery; a layer of negative electrode material is evenly coated on the copper wire by a scraping process. The negative electrode material is graphite and the coating thickness is 30μm to improve the charge and discharge efficiency of the battery.

[0055] S4, separator covering stage: a layer of aramid porous separator with a porosity of 40% is covered on the positive electrode material coating of the aluminum wire to achieve rapid ion transmission and battery safety performance;

[0056] S5, assembly and forming stage: The positive and negative electrodes and the separator are closely contacted by a twisting process to form a flexible battery wire. During the twisting process, the temperature is controlled to be 60°C and the contact pressure between the aluminum wire and the copper wire is 0.5MPa to improve the structural integrity and electrical contact performance of the battery wire. After the assembly is completed, the flexible battery wire is subjected to the same battery formation and testing as in Example 1.

[0057] It should also be pointed out that in the above embodiments, sodium can also be used as the coating material for the positive electrode material coating.

[0058] The flexible battery samples prepared in Examples 1-5 were tested for the initial discharge capacity / charge capacity in accordance with GB / T 31007-2014 (which mainly specifies the performance test standards for lithium-ion batteries, covering the test contents of battery capacity, cycle life, charge and discharge efficiency, safety, high temperature resistance, over-discharge protection, etc.). The test results are shown in the following table:

[0059] Example Test results (first discharge capacity / charge capacity) Example 1 80％ Example 2 85％ Example 3 90％ Example 4 92％ Example 5 95％

[0060] According to the above table, embodiment 3 has the following advantages over other embodiments:

[0061] 1. Better battery performance (first charge and discharge capacity)

[0062] The charge and discharge capacity of Example 3 is 90%, which is relatively moderate compared to Example 1 (80%), Example 2 (85%), Example 4 (92%) and Example 5 (95%), and is much higher than Example 1 and Example 2. Compared with Example 4 and Example 5, although the charge and discharge capacity is slightly lower, its overall design and material cost may be more balanced, which is suitable for the needs of both cost and performance.

[0063] 2. Moderate current collector diameter

[0064] Example 3 uses a current collector diameter of 200 μm, which has better mechanical strength and conductivity than Example 1 (50 μm) and Example 2 (100 μm), and still maintains good flexibility and low manufacturing cost compared to Example 4 (300 μm) and Example 5 (500 μm). A larger current collector diameter helps to improve the overall stability and current carrying capacity of the battery, but an overly large diameter (such as Example 4 and Example 5) may result in higher costs and material waste. Example 3 achieves a good balance between performance and cost.

[0065] 3. Moderate coating thickness

[0066] The coating thickness of the positive electrode and the negative electrode is 15 μm, respectively. Compared with Example 1 (5 μm) and Example 2 (10 μm), while ensuring the energy density of the battery, it can provide higher charging capacity and discharging capacity. Compared with Example 4 and Example 5, the coating thickness is moderate, avoiding the negative effects that may be caused by too thick coating (for example, increasing material cost, affecting flexibility, etc.).

[0067] 4. Reasonable porosity of isolation membrane

[0068] The porosity of the separator of Example 3 is 20%, which is higher than that of Example 1 (5%) and Example 2 (10%), which helps to improve the rapid transmission of ions and the charging and discharging efficiency and service life of the battery. At the same time, the porosity of the separator is also lower than that of Example 4 (30%) and Example 5 (40%). This moderate porosity helps to optimize the conductivity and mechanical strength of the battery.

[0069] 5. Moderate control of distortion temperature and pressure

[0070] The distortion temperature is 35°C and the distortion pressure is 0.3MPa. Compared with Example 1 (30°C, 0.1MPa) and Example 2 (35°C, 0.2MPa), Example 3 uses reasonable temperature and pressure values ​​while ensuring the integrity of the battery structure, avoiding damage to the material caused by excessive temperature and pressure. Compared with Examples 4 and 5, the temperature and pressure are lower, which helps to reduce energy consumption and improve production efficiency.

[0071] 6. Appropriate battery formation current and voltage

[0072] The battery formation current is 0.1-0.5C, and the battery formation voltage is 4.2V, which meets the standard requirements of conventional batteries and is suitable for long-term stable operation, ensuring that the battery has high performance stability under long-term use.

[0073] Summary: As the optimal embodiment, Example 3 has achieved a good balance in terms of capacity, battery structure, coating thickness, and separator porosity, and especially has achieved an appropriate compromise between battery performance, cost, and manufacturability. Therefore, it is superior in terms of comprehensive performance, production feasibility, and cost-effectiveness.

Claims

1. A method for manufacturing a flexible secondary battery, characterized in that: The following steps are involved: S1, using an aluminum wire with a diameter of 50 to 500 μm as a positive electrode current collector and a copper wire with a diameter of 50 to 500 μm as a negative electrode current collector; S2. Evenly apply a positive electrode material coating with a thickness of 5 to 30 μm on the surface of the aluminum wire, and evenly apply a negative electrode material coating with a thickness of 5 to 30 μm on the surface of the copper wire; S3, covering the positive electrode material coating of the aluminum wire with a layer of aramid porous separator with a porosity of 5% to 40%; S4. The copper wire processed in step S2 and the aluminum wire processed in step S3 are twisted and compounded by a twisting process, so that the positive electrode material coating, the aramid porous isolation membrane and the negative electrode material coating are in close contact to form a flexible battery wire.

2. The method for manufacturing a flexible secondary battery according to claim 1, characterized in that: The diameter of the aluminum wire is 100-300 μm, and the diameter of the copper wire is 100-300 μm.

3. The method for manufacturing a flexible secondary battery according to claim 1, characterized in that: The positive electrode material coating is lithium iron phosphate or sodium positive electrode material, and the negative electrode material coating is graphite negative electrode material.

4. The method for manufacturing a flexible secondary battery according to claim 1, characterized in that: The thickness of the positive electrode material coating is 15 to 20 μm, and the thickness of the negative electrode material coating is 15 to 20 μm.

5. The method for manufacturing a flexible secondary battery according to claim 1, characterized in that: In the step S2, a scraping coating process is used when coating the positive electrode material and the negative electrode material.

6. The method for manufacturing a flexible secondary battery according to claim 1, characterized in that: The porosity of the aramid porous isolation membrane is 10% to 30%.

7. The method for manufacturing a flexible secondary battery according to claim 1, characterized in that: The temperature of the twisting process in step S4 is controlled at room temperature to 60° C., and the contact pressure between the aluminum wire and the copper wire is 0.1 to 0.5 MPa.

8. The method for manufacturing a flexible secondary battery according to claim 1, characterized in that: Before coating the positive electrode material coating on the surface of the aluminum wire and coating the negative electrode material coating on the surface of the copper wire, the aluminum wire and the copper wire are subjected to surface treatment, wherein the surface treatment includes cleaning, activation and pre-coating treatment.

9. The method for manufacturing a flexible secondary battery according to claim 1, characterized in that: After the flexible battery wire is prepared, battery formation and testing are performed, and the battery formation and testing include constant current charging and constant voltage charging processes.

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