A high-temperature resistant lithium carbon fluoride battery and its manufacturing method

Abstract

This solution discloses a high-temperature-resistant lithium carbon monofluoride battery in the field of lithium battery technology, which includes a porous positive electrode, a double-layer separator, an electrolyte, and a negative electrode. The double-layer separator includes a first separator and a second separator, and the thickness, porosity, and melting point of the first separator and the second separator are different; the porous positive electrode has a multi-stage pore structure, with a pore diameter of 15-20 μm, a pore distribution of 1000-1200 pores / cm2, and a porosity of 57-65%; the porous positive electrode includes a porous carbon-coated current collector and a battery positive electrode material, and the dispersant in the battery positive electrode material is 0.1%-0.2%; the dispersant is a modified amino alcohol, which can be used both as a dispersant and as a pore-forming agent. Through the creative improvement of the double-layer separator, this application can significantly improve the high-temperature resistance of the lithium carbon monofluoride battery and enable the lithium carbon monofluoride battery to work stably for a long time under high-temperature conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium batteries, and particularly relates to a high-temperature lithium carbon monofluoride battery and a manufacturing method thereof. Background Art

[0002] Due to the high specific energy of lithium carbon monofluoride batteries, they have received special attention in the fields of national defense and aerospace. However, due to the relatively low conductivity of carbon monofluoride itself, the working voltage of lithium carbon monofluoride batteries is low, and lithium carbon monofluoride batteries generate serious heat under the condition of poor thermal conductivity, severely restricting the expansion of their applications.

[0003] In addition, the batteries in the oil and gas industry mainly include a positive electrode, a negative electrode, a separator, a casing material, an electrolyte, etc. In order to adapt to the high-temperature environment during oil and gas extraction, materials with good thermal stability need to be selected for the batteries. When a high-temperature lithium thionyl chloride (Li / SOCl2) battery operates at a temperature above 120°C, once the load current becomes abnormally large, the battery is extremely prone to thermal runaway, causing safety problems such as explosion and combustion. The thermal decomposition temperature of the graphite fluoride (CFx) positive electrode material is as high as over 500°C. Therefore, the Li / CFx battery has excellent high-temperature discharge performance. The Li / CFx battery has a relatively high theoretical specific energy (about 2180 W·h / kg) among primary lithium batteries and is expected to replace the Li / SOCl2 battery. The Li / CFx battery usually uses a flammable organic electrolyte, and the solvents used are mostly PC and DME, etc. The boiling point of DME is only 82 - 85°C. When exposed to an environment with a temperature higher than 85°C for a long time, it is extremely prone to leakage, resulting in battery failure and even safety problems such as combustion.

[0004] For example, a high-temperature lithium-ion battery mentioned in WO2017185703A1 adds a phosphoric anhydride-based water scavenger to the high-temperature lithium-ion battery electrolyte, enabling it to effectively eliminate trace water in the battery system, inhibit the generation of HF, and protect the electrochemical system in the battery. The examples disclose that after the high-temperature lithium-ion battery is fully charged and stored at 60°C for 90 days and then subjected to charge and discharge tests, the capacity recovery rate can reach more than 87%. When charging and discharging at 0.5C / 0.5C, 3.0 - 4.2V under the condition of 60°C ± 3°C, the capacity retention rate can still reach more than 87% after 500 cycles. The working temperature of the battery only increases to 60°C, far lower than the requirement of the minimum working temperature of 100°C underground.

[0005] As described in CN114628670A regarding the application of nitrogen-doped carbon-coated carbon fluoride in lithium / carbon fluoride batteries, a polydopamine carbon fluoride composite material is first obtained through the self-polymerization reaction of dopamine hydrochloride, and finally this composite material is calcined in an inert atmosphere to obtain a nitrogen-doped carbon-coated carbon fluoride electrode material. The presence of a uniform nitrogen-doped carbon coating on the surface of carbon fluoride reduces the self-discharge phenomenon of carbon fluoride batteries, thereby improving the high-temperature shelf performance of carbon fluoride batteries. Taking Example 1 as an example, at a rate of 0.1C, after being stored at 60°C for 30 days, it still has a relatively high discharge specific capacity of 600 mAh at room temperature, compared with 854 mAh before storage, showing a good discharge capacity retention rate. As described in CN112993289A regarding a lithium / carbon fluoride battery, the electrolyte for the lithium / carbon fluoride battery includes a lithium salt, an organic solvent, and a cyclic phosphate ester additive, and the organic solvent contains a fluorinated solvent. The free radicals generated in the electrolyte can effectively reduce the content of hydrogen free radicals generated by the decomposition of the electrolyte during high-temperature storage of the battery, reducing the electrode / electrolyte reaction rate, thereby significantly improving the high-temperature shelf performance of the Li / CFx battery. Taking Example 1 as an example, at 25°C, the 0.1C discharge specific capacity is 830 mAh / g. After being stored at 60°C for one week, the 0.1C, 25°C discharge specific capacity is 816 mAh / g. After being stored at 60°C for one month, the 0.1C, 25°C discharge specific capacity is 619 mAh / g. However, all the above batteries disclose only the improvement of the shelf performance of the battery at a temperature of 60°C, that is, by the accelerated test method at high temperature, the self-discharge rate of the battery is tested, and the discharge capacities of the above batteries are all measured at room temperature, without improving the discharge performance of the battery at high temperature. Considering the high-temperature requirements for downhole applications, generally above 100°C, it is necessary to redesign the battery to improve the thermal stability of the battery at higher temperatures and the stability of the working voltage for a long time to ensure safety during downhole operations.

[0006] Therefore, it is crucial to study a lithium carbon fluoride battery with high-temperature resistance characteristics that can work for a long time in a high-temperature environment. Summary of the Invention

[0007] The present invention aims to provide a high-temperature resistant lithium carbon fluoride battery and its manufacturing method. By setting a double-layer diaphragm and a porous electrode, the porous positive electrode and the second diaphragm are used to adsorb and lock more electrolyte, reducing the saturated vapor pressure of the solvent in the electrolyte and increasing the boiling point of the solvent, ensuring stable capacity output while improving the stability of the high-temperature discharge voltage of the battery; innovatively setting the porosity and melting point of the double-layer diaphragm to avoid damage to the second diaphragm caused by the expansion and extrusion of the high-temperature electrode. The lithium carbon fluoride battery prepared by the method of the present application not only has good high-temperature resistance characteristics but also has good high-temperature discharge performance, ensuring its stable operation at high temperatures for a long time.

[0008] A high-temperature lithium carbon monofluoride battery in this solution includes a porous positive electrode, a double-layer separator, an electrolyte, and a negative electrode. The double-layer separator includes a first separator and a second separator. The thickness of the first separator is 12 μm to 16 μm, the porosity is 40% to 53%, and the melting point is ≥160°C; the thickness of the second separator is 18 μm to 25 μm, the porosity is 47% to 70%, and the melting point is ≥200°C;

[0009] The porous positive electrode has a hierarchical pore structure, the pore diameter is 15 to 20 μm, and the pore distribution is 1000 to 1200 pieces / cm 2 , and the porosity is 57% to 65%; the porous positive electrode includes a porous carbon-coated current collector and a battery positive electrode material. The components included in the battery positive electrode material and their mass percentages are 92.5% to 95.5% of a porous carbon monofluoride material, 1.0% to 1.5% of a conductive agent, 1.6% to 3.0% of a first binder, 1.8% to 3.3% of a second binder, and 0.1% to 0.2% of a dispersant;

[0010] The dispersant is a modified amino alcohol, and the modified amino alcohol also serves as a pore-forming agent, including one or more of 2-aminoisobutanol, 2-dimethylamino-2-methyl-1-propanol, or 2-amino-1-butanol.

[0011] Furthermore, the pore diameter of the porous carbon monofluoride material is 55 to 160 nm, the specific surface area is 200 to 352 m 2 / g, and the porosity is 6% to 23%.

[0012] Furthermore, the electrolyte is formed by mixing a variety of high-boiling solvents and a lithium salt in proportion, and the electrolyte filling amount is 0.7 to 1.1 g / Ah.

[0013] Furthermore, the high-boiling solvents include at least one of PC, THF, GBL, TBP, and TTE.

[0014] Furthermore, the lithium salt includes at least one of LiBF4, LiTFSI, and LiClO4.

[0015] Furthermore, the conductive agent is a combination of at least one of single-walled carbon nanotubes and graphene and nanosilver wires.

[0016] Furthermore, the first binder is PVDF5130 or PVDF900.

[0017] Furthermore, the second binder is PTFE.

[0018] Furthermore, the negative electrode is metallic lithium, and the metallic lithium is welded to a nickel strip current collector.

[0019] This application also provides a manufacturing method of a high-temperature lithium carbon monofluoride battery, including the following steps:

[0020] Step 1: Prepare a porous positive electrode: Mix a first binder and a second binder according to a mass ratio to prepare a glue solution with a concentration of 6% - 10% to obtain Glue Solution 1; Mix a porous carbon fluoride material and a conductive agent according to a mass ratio, first perform ultrasonic treatment for 1 - 2 h, and then perform high-speed centrifugal dispersion for 20 - 40 min to obtain a mixture; Prepare a diluent with a concentration of 8% - 10% from a dispersant to obtain a dispersion; Then transfer Glue Solution 1 and the mixture into a blender for high-speed stirring and dispersion for 1 - 2 h; Then add the dispersion to the blender and continue high-speed stirring and dispersion for 6 - 8 h. Finally, under vacuum conditions, reverse the stirring paddle, with a stirring speed of 30 r / min and a time of 30 min to form a positive electrode slurry; Coat the positive electrode slurry on a porous carbon-coated current collector (porous carbon-coated aluminum foil), and obtain a porous carbon fluoride electrode precursor after vacuum drying; Perform hot rolling on the porous carbon fluoride electrode precursor, with a pressure of 0.8 MPa - 2.0 MPa, a speed of 0.5 m / s - 1.0 m / s, a rolling temperature of 120 - 130 °C, and 1 - 2 rolling passes, and obtain a porous positive electrode after cutting;

[0021] Step 2: Prepare a double-layer separator: First, prepare a PVDF glue solution with a viscosity of 1000 - 2000 mPa·s, coat the PVDF glue solution on the first layer of separator, cover the second layer of separator on the glue-coated surface of the first layer of separator, and dry at 60 °C to obtain a double-layer separator;

[0022] Step 3: Cut the porous positive electrode, double-layer separator, and negative electrode into appropriate sizes. Align the first layer of separator with the porous positive electrode and the second layer of separator with the negative electrode, assemble them into a cylindrical battery, seal the cover plate and the housing by laser welding, and add an electrolyte.

[0023] Beneficial effects of this solution:

[0024] 1. The porous positive electrode can adsorb more electrolyte, reduce the saturated vapor pressure of the solvent in the electrolyte, increase the boiling point of the solvent, which is beneficial to improving the stability of the battery's high-temperature discharge voltage and capacity output; The porous positive electrode can also quickly adsorb and lock high-concentration electrolyte, improving the liquid injection efficiency and the high-temperature discharge performance of the battery.

[0025] 2. The melting point of the second layer of separator ≥ 200 °C is beneficial to increasing the operating temperature of the battery. The high porosity of the second layer of separator can adsorb more electrolyte, reduce the saturated vapor pressure of the solvent in the electrolyte, increase the boiling point of the solvent, which is beneficial to improving the stability of the battery's high-temperature discharge voltage and capacity output.

[0026] 3. The melting point of the first-layer separator is ≥160°C. The porosities of the double-layer separator are different, and the porosity of the first-layer separator is relatively low, so that the tensile strength of the first-layer separator is much greater than that of the second-layer separator, effectively avoiding the situation that the second-layer separator is damaged due to the expansion and extrusion of the high-temperature electrode, which is beneficial to improving the stability of the high-temperature discharge voltage and the capacity output of the battery, and achieving the purpose of long-term stable operation of the lithium-carbon fluoride battery under high-temperature conditions.

[0027] 4. In this application, the dispersant is a modified amino alcohol, which can make the active material carry a charge. The active materials with the same kind of charge repel each other, reducing the agglomeration of the active materials and improving the dispersion uniformity.

[0028] 5. When the dispersant in this application is used as a pore-forming agent, since the modified amino alcohols are all high-concentration liquids, direct contact with the PVDF binder powder or high-concentration PVDF adhesive solution will damage the adhesiveness of PVDF. The present invention solves the problem that the modified amino alcohol will reduce the adhesiveness of PVDF by preferentially preparing a low-concentration PVDF adhesive solution and dispersion liquid. At the same time, the modified amino alcohol will volatilize during the hot rolling process, forming a pore structure with a gradient distribution inside the electrode. Description of the Drawings

[0029] Figure 1 is the discharge curve of the high-temperature resistant lithium-carbon fluoride batteries prepared in Example 1, Comparative Example 1 and Comparative Example 2 after being maintained at 130°C for 10 h;

[0030] Figure 2 is the discharge curve of the high-temperature resistant lithium-carbon fluoride batteries obtained in Example 2, Example 3 and Example 4 after being maintained at 130°C for 10 h;

[0031] Figure 3 is the discharge curve of the high-temperature resistant lithium-carbon fluoride batteries obtained in Example 2, Example 3 and Example 4 after being maintained at 150°C for 10 h. Detailed Embodiments

[0032] The following is further detailed through specific embodiments:

[0033] Example 1. A manufacturing method of a high-temperature resistant lithium-carbon fluoride battery includes the following steps:

[0034] Step 1: Raw material preparation: Prepare the battery cathode material, wherein the mass percentage of the porous carbon fluoride material is 92.5% - 95.5%, the mass percentage of the conductive agent is 1.0% - 1.5%, the mass percentage of the first binder is 1.6% - 3.0%, the mass percentage of the second binder is 1.8% - 3.3%, and the mass percentage of the dispersant is 0.1%; the pore diameter of the porous carbon fluoride material is 55 nm - 160 nm, and the specific surface area is 200 m 2 / g to 352 m 2 / g, with a porosity of 6 - 23%; the conductive agent consists of single-walled carbon nanotubes and nanosilver wires with a mass ratio of 1:1; the first binder is PVDF900; the second binder is PTFE; the dispersant is 2-aminoisobutanol;

[0035] The double-layer separator includes a first separator and a second separator. The first separator has a thickness of 15 μm, a porosity of 40%, and a melting point ≥ 160°C; the second separator has a thickness of 20 μm, a porosity of 47%, and a melting point ≥ 200°C; additionally, a porous carbon-coated current collector, electrolyte, negative electrode, cover plate, and housing are prepared. The porous carbon-coated current collector is a porous carbon-coated aluminum foil;

[0036] Step 2: Prepare the porous positive electrode: Mix the first binder and the second binder evenly to prepare an 8% glue solution to obtain Glue Solution 1; mix the porous carbon fluoride material and the conductive agent according to the mass ratio, first perform ultrasonic treatment for 1 h, and then perform high-speed centrifugal dispersion for 30 min to obtain a mixture; prepare a 10% dilution of the dispersant to obtain a dispersion; then transfer Glue Solution 1 and the mixture into a stirrer for high-speed stirring and dispersion for 1.5 h; then add the dispersion to the stirrer and continue high-speed stirring and dispersion for 7 h. Finally, under vacuum conditions, reverse the stirring paddle, with a stirring speed of 30 r / min for 30 min to form a positive electrode slurry; coat the positive electrode slurry on the porous carbon-coated current collector and obtain a porous carbon fluoride electrode precursor after vacuum drying; perform hot rolling on the porous carbon fluoride electrode precursor, with a pressure of 1.5 MPa, a speed of 0.8 m / s, a rolling temperature of 120°C, and 2 rolling passes, and obtain a porous positive electrode after cutting; the porous positive electrode has a multi-level pore structure, with a pore diameter of 15 - 20 μm and a porosity of 65%.

[0037] Step 3: Prepare the double-layer separator: First, prepare a PVDF glue solution with a viscosity of 1500 mPa·s, coat the PVDF glue solution on the first separator, cover the second separator on the coated surface of the first separator, and dry at 60°C to obtain the double-layer separator;

[0038] Step 4: Cut the porous positive electrode, double-layer separator, and negative electrode into appropriate sizes and assemble them into a cylindrical battery (specifically, during assembly, the first separator faces the porous positive electrode and the second separator faces the negative electrode); the cover plate and the housing are sealed by laser welding, and the electrolyte is added. The electrolyte filling amount is 1.1 g / Ah. The electrolyte is composed of a variety of high-boiling solvents and lithium salts mixed in proportion. The high-boiling solvents include PC, THF, and GBL with a mass ratio of 1:1:1, and the lithium salts include LiBF4 and LiTFSI with a mass ratio of 1:2.

[0039] Example 2. A manufacturing method of a high-temperature lithium carbon fluoride battery, including the following steps:

[0040] Step 1: Raw material preparation: Prepare the battery cathode material, where the mass percentage of the porous carbon fluoride material is 92.5% - 95.5%, the mass percentage of the conductive agent is 1.0% - 1.5%, the mass percentage of the first binder is 1.6% - 3.0%, the mass percentage of the second binder is 1.8% - 3.3%, and the mass percentage of the dispersant is 0.2%; the porous carbon fluoride material is the same as in Example 1; the conductive agent is composed of graphene and silver nanowires with a mass ratio of 1:1; the first binder is PVDF5130; the second binder is PTFE; the dispersant is 2-dimethylamino-2-methyl-1-propanol;

[0041] The double-layer separator includes a first separator and a second separator. The thickness of the first separator is 16μm, the porosity is 40%, and the melting point is ≥160°C; the thickness of the second separator is 18μm, the porosity is 47%, and the melting point is ≥200°C; additionally, prepare a porous carbon-coated current collector, electrolyte, negative electrode, cover plate, and housing. The porous carbon-coated current collector is a porous carbon-coated aluminum foil;

[0042] Step 2: Prepare the porous cathode: Mix the first binder and the second binder evenly to prepare a 10% glue solution to obtain Glue Solution 1; mix the porous carbon fluoride material and the conductive agent according to the mass ratio, first perform ultrasonic treatment for 1h, and then perform high-speed centrifugal dispersion for 20min to obtain a mixture; prepare a 9% dilution of the dispersant to obtain a dispersion; then transfer Glue Solution 1 and the mixture into a stirrer for high-speed stirring and dispersion for 1h; then add the dispersion to the stirrer and continue high-speed stirring and dispersion for 7h. Finally, reverse the stirring paddle under vacuum conditions, with a stirring speed of 30r / min and a time of 30min to form the cathode slurry; coat the cathode slurry on the porous carbon-coated current collector and obtain a porous carbon fluoride electrode precursor after vacuum drying; perform hot rolling on the porous carbon fluoride electrode precursor, with a pressure of 2MPa, a speed of 1m / s, a rolling temperature of 130°C, and 2 rolling passes, and obtain a porous cathode after cutting; the porous cathode has a multi-stage pore structure, with a pore diameter of 15 - 20μm and a porosity of 57%.

[0043] Step 3: Prepare the double-layer separator: First, prepare a PVDF glue solution with a viscosity of 2000m Pa·s, coat the PVDF glue solution on the first separator, cover the second separator on the glue-coated surface of the first separator, and dry it at 60°C to obtain the double-layer separator;

[0044] Step 4: Cut the porous positive electrode, double-layer separator, and negative electrode into appropriate sizes and assemble them into a cylindrical battery (specifically, during assembly, the first layer of separator faces the porous positive electrode, and the second layer of separator faces the negative electrode); the cover plate and the housing are sealed by laser welding, and electrolyte is added. The electrolyte filling amount is 0.7 g / Ah. The electrolyte is composed of a variety of high-boiling solvents and lithium salts mixed in proportion. The high-boiling solvents include PC, TBP, and TTE with a mass ratio of 1:1:1, and the lithium salts include LiBF4 and LiClO4 with a mass ratio of 1:2.

[0045] Example 3: A manufacturing method of a high-temperature lithium carbon monofluoride battery. The specific preparation method is the same as that of Example 1, except that: the content of the dispersant is 0.15%, the porosity of the first layer of separator is 53%, and the porosity of the second layer of separator is 47%.

[0046] Example 4: A manufacturing method of a high-temperature lithium carbon monofluoride battery. The specific preparation method is the same as that of Example 1, except that: the content of the dispersant is 0.18%, the porosity of the first layer of separator is 53%, and the porosity of the second layer of separator is 70%.

[0047] Comparative Example 1: A manufacturing method of a high-temperature lithium carbon monofluoride battery. The specific method is the same as that of Example 1, except that there are differences in raw materials. The difference is that: there is no second layer of separator, only the first layer of separator.

[0048] Comparative Example 2: A manufacturing method of a high-temperature lithium carbon monofluoride battery. The specific method is the same as that of Example 1, except that there are differences in raw materials. The difference is that: there is no first layer of separator, only the second layer of separator.

[0049] In the above examples, both the first layer of separator and the second layer of separator are polymer materials, which can be PP, PI, PET, PTFE, or PE.

[0050] The discharge curves of the high-temperature lithium carbon monofluoride batteries prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were tested at different temperatures. The specific situation is as shown in the appendix Figures 1 to 3 as follows.

[0051] The discharge performance of each group after being maintained at 25°C for 10 h is shown in Table 1 below:

[0052]

[0053] The discharge performance of each group after being maintained at 130°C for 10 h is shown in Table 2 below:

[0054]

[0055] The discharge performance of each group after being maintained at 150°C for 10 h is shown in Table 3 below:

[0056]

[0057]

[0058] As can be seen from the data in the above Tables 1 to 3, the lithium-carbon monofluoride battery provided by the method of the present invention not only has good high-temperature resistance characteristics, but also has the performance of working for a long time under high-temperature conditions, and the discharge capacity under high-temperature conditions is significantly higher than that under normal-temperature conditions.

[0059] The above are only embodiments of the present invention, and common knowledge such as specific structures and characteristics known in the solutions is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, and these should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicability of the patent. The protection scope required by this application shall be subject to the content of its claims, and the specific implementation manners and the like recorded in the specification can be used to interpret the content of the claims.

Claims

1. A high-temperature lithium carbon monofluoride battery, comprising a porous positive electrode, a double-layer separator, an electrolyte, and a negative electrode, characterized in that: The double-layer separator includes a first separator and a second separator. The first separator has a thickness of 12 µm to 16 µm, a porosity of 40% to 53%, and a melting point of ≥160 °C; the second separator has a thickness of 18 µm to 25 µm, a porosity of 47% to 70%, and a melting point of ≥200 °C; The porous positive electrode has a hierarchical pore structure with a pore diameter of 15 to 20 µm and a pore distribution of 1,000 to 1,200 pores / cm 2 , and the porosity is 57 to 65%; the porous positive electrode includes a porous carbon-coated current collector and a battery positive electrode material. The components included in the battery positive electrode material and their mass percentages are 92.5% to 95.5% of a porous carbon fluoride material, 1.0% to 1.5% of a conductive agent, 1.6% to 3.0% of a first binder, 1.8% to 3.3% of a second binder, and 0.1% to 0.2% of a dispersant. The first binder is PVDF, and the second binder is PTFE; The dispersant is a modified amino alcohol, and the modified amino alcohol also serves as a pore-forming agent, including one or more of 2-aminoisobutanol, 2-dimethylamino-2-methyl-1-propanol, or 2-amino-1-butanol.

2. The high-temperature lithium carbon monofluoride battery according to claim 1, wherein: The pore size of the porous carbon fluoride material is 55 to 160 nm, the specific surface area is 200 to 352 m 2 / g, and the porosity is 6 to 23%.

3. The high-temperature lithium carbon fluoride battery according to claim 1, characterized in that: The electrolyte is formed by mixing a variety of high-boiling solvents and a lithium salt in proportion, and the electrolyte filling amount is 0.7 to 1.1 g / Ah.

4. The high-temperature lithium carbon fluoride battery according to claim 3, wherein: The high-boiling solvents include at least one of PC, THF, GBL, TBP, and TTE.

5. The high-temperature lithium carbon fluoride battery according to claim 4, wherein: The lithium salts include at least one of LiBF4, LiTFSI, and LiClO4.

6. The high-temperature lithium carbon monofluoride battery according to claim 1, characterized in that: The conductive agent is a combination of at least one of single-walled carbon nanotubes and graphene and nanosilver wires.

7. The high-temperature lithium carbon monofluoride battery according to claim 1, wherein: The first binder is PVDF5130 or PVDF900.

8. A high-temperature lithium carbon monofluoride battery according to claim 1, characterized in that: The negative electrode is metallic lithium, and the metallic lithium is welded to a nickel strip current collector.

9. A manufacturing method of a high-temperature lithium carbon monofluoride battery according to any one of claims 3 to 8, characterized in that: It includes the following steps: Step 1: Prepare a porous positive electrode: Mix the first binder and the second binder according to a mass ratio to prepare a glue solution with a concentration of 6% to 10% to obtain glue solution 1; mix the porous carbon fluoride material and the conductive agent according to a mass ratio, first perform ultrasonic treatment for 1 to 2 h, and then perform high-speed centrifugal dispersion for 20 to 40 min to obtain a mixture; prepare a diluent with a concentration of 8% to 10% from the dispersant to obtain a dispersion; then transfer the glue solution 1 and the mixture into a mixer for high-speed stirring and dispersion for 1 to 2 h; then add the dispersion to the mixer and continue high-speed stirring and dispersion for 6 to 8 h. Finally, under vacuum conditions, reverse the stirring paddle, with a stirring speed of 30 r / min for 30 min to form a positive electrode slurry; coat the positive electrode slurry on a porous carbon-coated current collector, and obtain a porous carbon fluoride electrode precursor after vacuum drying; perform hot rolling on the porous carbon fluoride electrode precursor, with a pressure of 0.8 MPa to 2.0 MPa, a speed of 0.5 m / s to 1.0 m / s, a rolling temperature of 120 to 130 °C, and 1 to 2 rolling passes, and obtain a porous positive electrode after cutting; Step 2: Prepare a double-layer separator: First, prepare a PVDF glue solution with a viscosity of 1000 to 2000 mPa·s, coat the PVDF glue solution on the first separator, cover the second separator on the glue-coated surface of the first separator, and dry it at 60 °C to obtain a double-layer separator; Step 3: Cut the porous positive electrode, double-layer separator, and negative electrode into appropriate sizes, align the first separator with the porous positive electrode and the second separator with the negative electrode, assemble them into a cylindrical battery, seal the cover plate and the housing by laser welding, and add the electrolyte.

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