Method and device for improving low-temperature cycle performance of lithium iron phosphate battery

Abstract

The application discloses a method and device for improving low-temperature cycle performance of a lithium iron phosphate battery, belongs to the technical field of battery improvement, and aims at the problem of unstable low-temperature discharge of the existing lithium iron phosphate battery, and proposes the following scheme, which comprises the following steps: S1: other compound ions are doped in a bulk phase of an anode lithium iron phosphate raw material, impregnation is carried out by using an impregnation process, and the surface crystal structure of the lithium iron phosphate is changed; S2: a material layer is coated on the surface of the lithium iron phosphate generated in the step S1; and S3: after the battery is installed, modified substances are added into an electrolyte of the lithium iron phosphate battery, and modification is carried out; the application has the advantages of simple structure, convenient use, increased service life of the battery, improved performance of the battery at low temperature by cooperating with the matched electrolyte, and ensured safe and stable use of the battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery improvement, in particular to a method and device for improving low-temperature cycle performance of lithium iron phosphate battery. BACKGROUND

[0002] The lithium iron phosphate battery is a lithium ion battery using lithium iron phosphate (LiFePO4) as a positive material and carbon as a negative material. During charging, part of lithium ions in the lithium iron phosphate are released, transferred to the negative electrode through the electrolyte, and embedded in the negative electrode carbon material. At the same time, electrons are released from the positive electrode and reach the negative electrode from the external circuit to maintain the balance of the chemical reaction. During discharging, lithium ions are released from the negative electrode, reach the positive electrode through the electrolyte, and at the same time, the negative electrode releases electrons, reaches the positive electrode from the external circuit, and provides energy to the outside world.

[0003] However, the existing battery is unstable during discharging in actual use, especially in a low-temperature environment. The chemical reaction rate is unstable, and the battery capacity is reduced, which makes the whole battery use bad. The existing institutions generally use pulse heating to ensure normal working efficiency, but the overall energy is wasted, and the waiting time is long. SUMMARY

[0004] The method and device for improving low-temperature cycle performance of lithium iron phosphate battery solve the problem of unstable low-temperature discharging.

[0005] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0006] A method for improving low-temperature cycle performance of lithium iron phosphate battery, comprising the following steps:

[0007] S1: Doping other compound ions in the anode lithium iron phosphate raw material, and using the immersion process to change the surface crystal structure of the lithium iron phosphate;

[0008] S2: Coating a material layer on the surface of the lithium iron phosphate produced in step S1;

[0009] S3: After the battery is installed, adding a modified substance to the electrolyte of the lithium iron phosphate battery for modification.

[0010] Preferably, the modified substance includes but is not limited to LiBF-LiBOB mixed salt, lithium borate (LiODFB), the coating layer uses a metal material, preferably an oxide thereof, and the other compound particles are Mg particles or La ions.

[0011] Preferably, step S and step S need to use a production device, and the production device comprises:

[0012] A material receiving box, which is sequentially connected with a treatment box, an immersion box, an adding box and a purification box.

[0013] The feed pipe is connected to one side of the impregnation tank, and the discharge pipe connected to the impregnation tank is provided on the opposite side of it.

[0014] The coating tube has one end connected to the discharge tube and the other end connected to a stabilizing tube connected to the receiving box.

[0015] The feeding mechanism is provided in multiple ways, and the multiple feeding mechanisms are arranged in sequence and are rotatably connected to the feeding pipe, the impregnation tank and the discharge pipe.

[0016] The spraying mechanism is provided in multiple evenly distributed units, and a stabilizing mechanism is provided between two spraying mechanisms. Both the spraying mechanism and the stabilizing mechanism are rotatably connected to the coating tube.

[0017] The reinforcement mechanism consists of multiple parts, which are rotatably connected inside the stabilizing tube.

[0018] The circulation mechanism is located inside the processing tank, and its output end is connected to the impregnation tank.

[0019] Preferably, the feeding mechanism includes:

[0020] The first rotating tube, and multiple rotating tubes are respectively rotatably connected to the feed tube, the impregnation tank, and the discharge tube. Multiple insulating blocks are embedded in its inner wall, and a chain tooth is fixedly connected to one end of its tube.

[0021] An extension tube, one end of which is fixed to an insulating block, and the other end of which is fixedly connected to a first limiting tube, and a control tube is connected to one side of the first limiting tube;

[0022] The first protective ring is fixedly adjusted on the rotating tube and is fixedly connected to the first limiting tube;

[0023] The first spring has one end fixedly connected to the first limiting tube, and the other end fixedly connected to a contact cone that is slidably connected to the protective ring.

[0024] The through hole is located inside the contact cone, with one end connected to the outside and the other end connected to the first limiting tube.

[0025] The contact block is fixedly connected inside the insulating block, and one side of it is electrically connected to the contact cone via a wire.

[0026] A transmission rod is located inside the rotating tube, and a conductive rod is connected to one side of it. One end of the conductive rod is fixedly connected to a sliding block that contacts the contact block.

[0027] Preferably, the spraying mechanism includes:

[0028] The second rotating tube is rotatably connected to the coating tube, and a second protective ring is fixedly connected to its outer wall.

[0029] The second limiting tube is provided in multiple forms and is evenly fixed on the second rotating tube. A second spring is fixedly connected inside the tube, and the other end of the second spring is fixedly connected to a pressing rod that is slidably sleeved with the second limiting tube. The pressing rod is slidably sleeved with the second protective ring, and a rolling ring is rotatably connected to one end of the pressing rod.

[0030] The third limiting tube is provided in multiple forms and is evenly fixed on the rotating tube. A third spring is fixedly connected inside the tube, and the other end of the third spring is fixedly connected to a feeding rod that is slidably sleeved with the second limiting tube. A conductive tube is connected between the third limiting tube and the second limiting tube.

[0031] The feed holes are provided in multiple ways and are evenly distributed on the second limiting tube. One end of the feed rod is located inside the feed hole.

[0032] Preferably, the stabilizing mechanism includes:

[0033] The third rotating tube is rotatably connected to the coating tube, and a third protective ring is fixedly connected to its outer wall. Multiple heating tubes are fixedly connected inside the third protective ring.

[0034] The fourth limiting tube is provided in multiple forms and is evenly fixed on the third rotating tube. A fourth spring is fixedly connected inside the tube, and the other end of the fourth spring is fixedly connected to a stabilizing tube that is slidably sleeved with the fourth limiting tube. The stabilizing tube is slidably sleeved with the third protective ring.

[0035] The contact hole is located inside the stabilizing tube, and one end of it is connected to the outside.

[0036] The feed holes are located on the third rotating tube, and there are multiple of them.

[0037] Preferably, the reinforcement mechanism includes a fourth rotating tube rotatably connected to the stabilizing tube, a fourth protective ring is fixedly connected to the outer wall of the fourth rotating tube, and a plurality of heating wires are fixedly connected inside the fourth protective ring.

[0038] Preferably, the circulation mechanism includes:

[0039] The conveying pump is fixedly connected to the bottom of the processing tank, and its input end is connected to a suction pipe that is connected to the receiving tank.

[0040] A central tank is located inside the processing tank, and its top is connected to a vent pipe that communicates with the impregnation tank. The output end of the delivery pump is connected to the central tank.

[0041] A retaining plate is connected to a discharge pipe, the bottom of which is provided with multiple leakage holes, and the bottom of the retaining plate is connected to a retaining pipe connected to an impregnation tank.

[0042] The fan is fixedly connected to the feed pipe, with its input end extending into the feed pipe and its output end connected to the air outlet pipe connected to the purification box.

[0043] The discharge pipe is connected to the addition tank, and its other end extends into the impregnation tank. An electromagnetic flow control valve is connected to the discharge pipe.

[0044] An apparatus for improving the low-temperature cycling performance of lithium iron phosphate batteries, comprising:

[0045] The battery box has a protective plate inside and a connecting box on top.

[0046] The battery panel is located inside the connecting box, and circulation tubes are fixedly connected to the battery box on both sides of the panel, with the other end of the circulation tubes extending into the connecting box.

[0047] A circulating pump is fixedly connected inside the connection box, with its input end connected to a circulating pipe on one side and its output end connected to a mixing pipe.

[0048] A mixing chamber with a storage cavity inside, the storage cavity being connected to a guide pipe that is connected to a mixing pipe;

[0049] The reflux pipe is connected at one end to the mixing pipe and at the other end to the circulation pipe on one side.

[0050] The beneficial effects of this invention are:

[0051] 1. By impregnating and coating lithium iron phosphate, its surface properties are improved, which can increase the battery's lifespan. Combined with the formulated electrolyte, it can improve battery performance at low temperatures and ensure safe and stable battery use.

[0052] 2: By operating multiple devices, durable batteries can be produced quickly and stably, increasing overall production efficiency and capacity while ensuring production quality, saving manpower and resources, and reducing production costs. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the main sectional view of the production equipment for the method and apparatus for improving the low-temperature cycle performance of lithium iron phosphate batteries proposed in this invention.

[0054] Figure 2 This is a front sectional view of the feeding mechanism of a method and apparatus for improving the low-temperature cycle performance of lithium iron phosphate batteries proposed in this invention.

[0055] Figure 3 This is a left-side cross-sectional view of the feeding mechanism of a method and apparatus for improving the low-temperature cycle performance of lithium iron phosphate batteries proposed in this invention.

[0056] Figure 4This is a partial front sectional view of the feeding mechanism of a method and apparatus for improving the low-temperature cycle performance of lithium iron phosphate batteries proposed in this invention.

[0057] Figure 5 This is a front sectional view of the spraying mechanism of the method and apparatus for improving the low-temperature cycle performance of lithium iron phosphate batteries proposed in this invention.

[0058] Figure 6 This is a front cross-sectional view of the stabilization mechanism of the method and apparatus for improving the low-temperature cycle performance of lithium iron phosphate batteries proposed in this invention.

[0059] Figure 7 This is a partial front sectional view of the stabilization mechanism of the method and apparatus for improving the low-temperature cycle performance of lithium iron phosphate batteries proposed in this invention.

[0060] Figure 8 This is a front sectional view of the reinforcement mechanism of the method and apparatus for improving the low-temperature cycle performance of lithium iron phosphate batteries proposed in this invention.

[0061] Figure 9 This is a schematic diagram of a battery for a method and apparatus for improving the low-temperature cycling performance of lithium iron phosphate batteries proposed in this invention.

[0062] Numbered in the diagram: 1. Receiving box; 3. Reinforcing mechanism; 4. Stabilizing pipe; 5. Stabilizing mechanism; 6. Coating pipe; 7. Spraying mechanism; 8. Discharge pipe; 9. Feeding mechanism; 10. Unloading pipe; 11. Adding box; 12. Purification box; 13. Air outlet pipe; 14. Fan; 15. Feeding pipe; 16. Impregnation box; 18. Processing box; 19. Suction pipe; 20. Centralized box; 21. Conveying pump; 22. Ventilation pipe; 23. Interception pipe; 24. Interception plate; 30. Fourth protective ring; 31. Fourth rotating pipe; 32. Heating wire; 40. Battery box; 41. Battery panel; 42. Protective plate; 43. Circulation pipe; 44. Connecting box; 45. Return pipe; 46. Mixing box; 47. Guide pipe; 48. Mixing pipe; 49. Storage chamber; 4 10. Circulating pump; 50. Third protective ring; 51. Stabilizing tube; 52. Fourth limiting tube; 53. Heating tube; 54. Fourth spring; 55. Third rotating tube; 56. Contact hole; 57. Feeding hole; 70. Second protective ring; 71. Rolling ring; 72. Extrusion rod; 73. Feeding rod; 74. Third limiting tube; 75. Conducting tube; 76. Third spring; 77. Second spring; 78. Second rotating tube; 79. Second limiting tube; 90. First protective ring; 91. Contact cone; 92. Extension tube; 93. Conductive rod; 94. Transmission rod; 95. Contact block; 96. First rotating tube; 97. Chain tooth; 98. Insulating block; 99. Conducting hole; 910. First spring; 911. First limiting tube; 912. Control tube. Detailed Implementation

[0063] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0064] Reference Figures 1-9 A method for improving the low-temperature cycling performance of lithium iron phosphate batteries includes the following steps:

[0065] S1: Other compound ions are doped into the bulk phase of the lithium iron phosphate anode raw material and impregnated using an impregnation process to change the surface crystal structure of lithium iron phosphate. Impregnation causes other particles to be doped into a portion of its surface, thereby reducing resistivity.

[0066] S2: The surface coating material layer of lithium iron phosphate produced in step S1 is also used to reduce resistivity and reduce ion adsorption during subsequent reactions. However, the coating layer does not completely coat the surface, forming a layered structure with certain intervals.

[0067] S3: After the battery is installed, a modifier is added to the lithium iron phosphate battery electrolyte to modify it. The modifier is added in small amounts to increase the stability of the electrolyte while ensuring the reaction rate during use.

[0068] The modified materials include, but are not limited to, mixed salts of LiBF4-LiBOB and lithium borate (LiODFB), the coating layer is made of metallic materials, preferably oxides thereof, and other compound particles are Mg particles or La ions.

[0069] Performing steps S1 and S2 requires the use of a production apparatus, which includes:

[0070] The receiving box 1 is connected in sequence to the processing box 18, the impregnation box 16, the adding box 11, and the purification box 12. The receiving box 1 provides support and collects finished products. The collected lithium iron phosphate plates are cut into smaller pieces according to subsequent use to meet different work needs. The processing box 18 processes some of the gas. The impregnation box 16 performs the necessary impregnation work. The adding box 11 adds raw materials to the impregnation box 16 to ensure the needs of the work.

[0071] The feed pipe 15 is connected to one side of the impregnation tank 16, and the discharge pipe 8 connected to the impregnation tank 16 is provided on the opposite side. The raw material enters the impregnation tank 16 through the feed pipe 15 and then exits through the discharge pipe 8.

[0072] The coating tube 6 is connected at one end to the discharge tube 8 and at the other end to the stabilizing tube 4 connected to the receiving box 1. The coating tube 6 is used for necessary coating, and the stabilizing tube 4 reinforces the previous process to ensure the stability of the quality of the finished product entering the receiving box 1.

[0073] The feeding mechanism 9 is provided in multiple ways, and the multiple feeding mechanisms 9 are arranged in sequence. They are rotatably connected to the feeding pipe 15, the immersion tank 16, and the discharge pipe 8. The feeding mechanism 9 ensures the feeding process and works with the spraying mechanism 7, the stabilizing mechanism 5, and the reinforcing mechanism 3 to transport the raw materials.

[0074] The spraying mechanism 7 is provided in multiple and evenly distributed. A stabilizing mechanism 5 is provided between two spraying mechanisms 7. Both the spraying mechanism 7 and the stabilizing mechanism 5 are rotatably connected to the coating pipe 6.

[0075] The reinforcement mechanism 3, which has multiple components, is rotatably connected inside the stabilizing tube 4. The reinforcement mechanism 3 performs necessary spraying work on the sprayed material to ensure stability during subsequent use.

[0076] The circulation mechanism is installed inside the processing tank 18, and its output end is connected to the impregnation tank 16. The circulation mechanism enables the internal energy or other substances to circulate to a certain extent, so as to minimize waste and save resources.

[0077] Feeding mechanism 9 includes:

[0078] The first rotating tube 96 has multiple rotating tubes that are rotatably connected to the feed tube 15, the impregnation tank 16, and the discharge tube 8, respectively. Multiple insulating blocks 98 are embedded in its inner wall, and a chain tooth 97 is fixedly connected to one end of the tube. The first rotating tube 96 can rotate on the feed tube 15, the impregnation tank 16, and the discharge tube 8. At the same time, the insulating blocks 98 on it can provide insulation to ensure the stability of subsequent operations.

[0079] The extension tube 92 has one end fixed to the insulating block 98 and the other end fixedly connected to the first limiting tube 911. A control tube 912 is connected to one side of the first limiting tube 911, and a one-way valve is connected to the control tube 912. The extension tube 92 is extended and stabilized as necessary, and at the same time, it feeds and discharges material into the first limiting tube 911 through the control tube 912.

[0080] The first protective ring 90 is fixedly adjusted on the first rotating tube 96 and is fixedly connected to the first limiting tube 911. The protective ring 90 separates the inside and outside into two environments to ensure the operation.

[0081] The first spring 910 has one end fixedly connected to the first limiting tube 911, and the other end fixedly connected to a contact cone 91 that is slidably connected to the protective ring 90.

[0082] The through hole 99 is located inside the contact cone 91. One end of it is connected to the outside and the other end is connected to the first limiting tube 911. The contact cone 91 can move as necessary through the limitation of the first spring 910 to reduce excessive pressure. At the same time, the raw material transmitted through the first rotating tube 96 is sprayed through the through hole to add the raw material.

[0083] The contact block 95 is fixedly connected inside the insulating block 98. One side of it is electrically connected to the contact cone 91 via a wire. The power from the outside is transmitted to the conductive rod 93 via the transmission rod 94, and then to the contact block 95 to transmit the power.

[0084] The transmission rod 94 is located inside the first rotating tube 96, and a conductive rod 93 is connected to one side of it. One end of the conductive rod 93 is fixedly connected to a sliding block 913 that contacts the contact block 95.

[0085] The spraying mechanism 7 includes:

[0086] The second rotating tube 78 is rotatably connected to the coating tube 6, and a second protective ring 70 is fixedly connected to its outer wall. The second rotating tube 78 rotates as necessary, and at the same time drives the second protective ring 70 to rotate.

[0087] Multiple second limiting tubes 79 are provided and are evenly fixed on the second rotating tube 78. A second spring 77 is fixedly connected inside the tube, and the other end of the second spring 77 is fixedly connected to a pressing rod 72 that is slidably sleeved with the second limiting tube 79. The pressing rod 72 is slidably sleeved with the second protective ring 70. One end of the pressing rod 72 is rotatably connected to a rolling ring 71. During rotation, the rolling ring 71 intermittently contacts the raw material, thereby causing the pressing rod 72 to move, which reduces the space in the second limiting tube 79 and further allows the gas inside to enter the third limiting tube 74.

[0088] Multiple third limiting tubes 74 are provided and evenly fixed on the second rotating tube 78. A third spring 76 is fixedly connected inside the third limiting tube 74, and the other end of the third spring 76 is fixedly connected to a feeding rod 73 that is slidably sleeved with the second limiting tube 79. A conducting tube 75 connects the third limiting tube 74 and the second limiting tube 79. External gas enters the third limiting tube 74, which causes the feeding tube 73 to move. The raw material transmitted through the second rotating tube 78 to the second protective ring 70 enters the feeding hole and is then sprayed out to add raw material and complete the coating work in part of the area.

[0089] The feed holes are provided in multiple ways and are evenly distributed on the second limiting tube 79. One end of the feed rod 73 is located inside the feed hole.

[0090] Stabilizing agency 5 includes:

[0091] The third rotating tube 55 is rotatably connected to the coating tube 6. A third protective ring 50 is fixedly connected to its outer wall. Multiple heating tubes 53 are fixedly connected inside the third protective ring 50. After being sprayed by the spraying mechanism 7, the heating tubes are pressed and compacted by the third protective ring 50.

[0092] The fourth limiting tube 52 is provided in multiple forms and is evenly fixed on the third rotating tube 55. A fourth spring 54 is fixedly connected inside the tube, and the other end of the fourth spring 54 is fixedly connected to a stabilizing tube 51 that is slidably sleeved with the fourth limiting tube 52. The stabilizing tube 51 is slidably sleeved with the third protective ring 50. Under the action of the fourth spring 54, the stabilizing tube 51 indirectly contacts the raw material. At the same time, when in contact, the raw material transmitted through the third rotating tube 55 and the feeding hole 57 is sprayed through the contact hole 56 to reinforce the coated raw material.

[0093] Contact hole 56 is located inside the stabilizing tube 51, and one end of it is connected to the outside.

[0094] Feed holes 57 are provided on the third rotating tube 55, and there are multiple of them.

[0095] The reinforcement mechanism 3 includes a fourth rotating tube 31 that is rotatably connected to the stabilizing tube 4. A fourth protective ring 30 is fixedly connected to the outer wall of the fourth rotating tube 31. Multiple heating wires 32 are fixedly connected inside the fourth protective ring 30. The raw material is heated by the heating wires 32 to soften it. Then, after being squeezed by the fourth protective ring 30, the materials are finally stabilized on the surface of the lithium iron phosphate plate, thus achieving stable operation.

[0096] The circulation mechanism includes:

[0097] The conveying pump 21 is fixedly connected to the bottom of the processing box 18. Its input end is connected to the suction pipe 19 connected to the receiving box 1. The conveying pump 21 transports the high-temperature gas in the receiving box 1 upwards and moves it to realize the transportation work.

[0098] The central chamber 20 is located inside the processing chamber 18. Its top is connected to a vent pipe 22 that communicates with the impregnation chamber 16. The output end of the transfer pump 21 is connected to the central chamber 20. The central chamber provides necessary buffering, and then the hot air enters the impregnation chamber 16 through the vent pipe 22, raising the temperature of the liquid in the impregnation chamber 16 and accelerating the reaction rate.

[0099] The intercepting plate 24 is connected to the discharge pipe 8. The bottom of the discharge pipe 8 is provided with multiple leakage holes. The bottom of the intercepting plate 24 is connected to the intercepting pipe 23, which is connected to the impregnation tank 16. The intercepting plate 24 collects the liquid carried out by the raw material in the discharge pipe 8, and then the liquid passes through the intercepting pipe 23 and re-enters the impregnation tank 16 to ensure the needs of the operation.

[0100] The blower 14 is fixedly connected to the feed pipe 15. Its input end extends into the feed pipe 15, and its output end is connected to the air outlet pipe 13 connected to the purification box 12. The blower 14 draws in the gas that may evaporate and enters the purification box 12 through the air outlet pipe 13. The purification box 12 is filled with purification material to reduce pollution to the environment.

[0101] The discharge pipe 10 is connected to the addition tank 11, and the other end extends into the impregnation tank 16. An electromagnetic flow control valve is connected to the discharge pipe 10. The discharge pipe 10 adds the raw material in the addition tank 11 to the impregnation tank 16 to ensure the concentration of the liquid.

[0102] Each of the first rotating tube 96, the second rotating tube 78, and the third rotating tube 55 is rotatably connected to a feeding device at one end to ensure real-time supply of raw materials. The feeding device is an existing structure that can supply external raw materials under pressure. The outer walls of the first rotating tube 96, the second rotating tube 78, the third rotating tube 55, and the fourth rotating tube 31 are all connected to chain wheels with chains connected to them. A mechanism for pressing the chains is also in place. An external motor drives the chains to achieve synchronous rotation of multiple rotating tubes. Brushes are connected to the transmission rod 94, the third rotating tube 55, and the fourth rotating tube 31 to ensure the supply of internal power.

[0103] An apparatus for improving the low-temperature cycling performance of lithium iron phosphate batteries, comprising:

[0104] The battery box 40 has a protective plate 42 inside and a connecting box 44 on top. The battery box 40 provides necessary protection for the battery, the protective plate 42 provides auxiliary fixation for the internal components of the battery, and the connecting box 44 provides protection for the auxiliary mechanism.

[0105] The battery panel 41 is located inside the delivery box 40. It has circulation pipes 43 fixedly connected to the battery box 40 on both sides, and the other end of the circulation pipes 43 extends into the connection box 44. The battery panel 41 is a lithium iron phosphate battery panel that has been produced as described above, and the outside is filled with electrolyte located inside the battery box 40.

[0106] The circulating pump 410 is fixedly connected in the connecting box 44. Its input end is connected to the circulating pipe 43 on one side, and its output end is connected to the mixing pipe 48.

[0107] The mixing tank 46 has a storage chamber 49 inside, which is connected to a guide pipe 47 that is connected to the mixing pipe 48. Through the indirect circulation of the circulation pump 410, the electrolyte inside is circulated to a certain extent. During the circulation process, a concentration detector is placed in the guide pipe 47. When the concentration drops, the raw materials in the storage chamber 49 are released through the guide pipe 47 to ensure the concentration of the electrolyte.

[0108] The return pipe 45 is connected at one end to the mixing pipe 48 and at the other end to the circulation pipe 43 on one side.

[0109] Working Principle: When improving lithium iron phosphate batteries, modified battery panels need to be produced. During production, raw materials are placed in the feed pipe 15 and then transported through the feeding mechanism 9. During transport, the contact cone 91 indirectly contacts the panel. Due to compression and impact, the surface of the panel develops slight indentations. Simultaneously, when the contact cone 91 contacts the panel, the energization of the transfer rod 94 causes a spark discharge between the contact cone 91 and the panel, generating a reaction. This allows trace amounts of material in the impregnation chamber to quickly concentrate and fix onto the surface of the panel and into the thinner layers. Adjusting the position of the transfer rod 94 allows for stepless circumferential adjustment, ensuring the completion of each point on the panel during transport. After transport, the material passes through the discharge pipe 8. Excess liquid falls into the intercepting plate 24 under gravity and then enters the coating pipe 6. At this point, the rolling ring 71 on the spraying mechanism 7 contacts the panel and is compressed. Then, through the transmission through the guide pipe 75, the feeding rod 73 moves, applying pressure to a larger area of ​​the raw material. The coating is initially compacted by the rear rolling ring 71, and then further compacted by the third protective ring 50 in the stabilizing mechanism 5. The heating tube 53 heats the material to a certain extent to soften it and ensure the compaction effect. At the same time, the stabilizing tube 51 is squeezed to open the contact hole 56, and the material inside is sprayed out through the contact hole 56 under pressure to cover and protect the surface. Then it enters another spraying mechanism 7 for a cycle to ensure that multiple points are covered by the coating. Finally, it is squeezed and heated by the reinforcing mechanism 3 to complete the curing and enter the receiving box 1. In subsequent use, it is cut into the specified size and placed in the battery box 40. When in use, electrolyte with additives is added and circulated by the circulation pump 410 to reduce the precipitation that may occur during long-term use. In conjunction with the work of the storage chamber 49 and the guide tube 47, electrolyte can be added to ensure the concentration of electrolyte, maintain a suitable working range, achieve relatively stable use, and reduce the impact of low temperature.

[0110] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0111] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0112] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for improving the low-temperature cycle performance of lithium iron phosphate batteries, characterized in that, Includes the following steps: S1: Other compound ions are doped into the bulk phase of the lithium iron phosphate anode raw material and impregnated using an impregnation process to change the surface crystal structure of lithium iron phosphate. S2: The surface coating material layer of lithium iron phosphate produced in step S1; S3: After the battery is installed, add a modifying substance to the lithium iron phosphate battery electrolyte to modify it; The execution of steps S1 and S2 requires the use of a production device, which includes: The receiving box (1) is connected in sequence to the processing box (18), the impregnation box (16), the addition box (11) and the purification box (12). The feed pipe (15) is connected to one side of the impregnation tank (16), and the discharge pipe (8) connected to the impregnation tank (16) is provided on its opposite side. The coating tube (6) is connected at one end to the discharge tube (8) and at the other end to the stabilizing tube (4) connected to the receiving box (1). The feeding mechanism (9) is provided in multiple ways, and the multiple feeding mechanisms (9) are arranged in sequence. The feeding mechanism (9) is rotatably connected to the feeding pipe (15), the impregnation tank (16), and the discharge pipe (8). The spraying mechanism (7) is provided in multiple and evenly distributed. A stabilizing mechanism (5) is provided between two spraying mechanisms (7). Both the spraying mechanism (7) and the stabilizing mechanism (5) are rotatably connected to the coating tube (6). The reinforcement mechanism (3) is provided in multiple parts and is rotatably connected inside the stabilizing tube (4); A circulation mechanism is provided inside the processing tank (18), and its output end is connected to the impregnation tank (16); The feeding mechanism (9) includes: The first rotating tube (96) is rotatably connected to the feed tube (15), the impregnation tank (16) and the discharge tube (8) respectively. Multiple insulating blocks (98) are embedded in its inner wall, and a chain tooth (97) is fixedly connected to one end of it. An extension tube (92) is fixed at one end to an insulating block (98) and at the other end is fixedly connected to a first limiting tube (911). A control tube (912) is connected to one side of the first limiting tube (911). The first protective ring (90) is fixedly adjusted on the first rotating tube (96) and is fixedly connected to the first limiting tube (911); The first spring (910) has one end fixedly connected to the first limiting tube (911), and the other end is fixedly connected to a contact cone (91) that is slidably connected to the protective ring (90). The through hole (99) is located inside the contact cone (91), with one end connected to the outside and the other end connected to the first limiting tube (911); The contact block (95) is fixedly connected inside the insulating block (98), and one side of it is electrically connected to the contact cone (91) via a wire; The transmission rod (94) is located inside the first rotating tube (96), and a conductive rod (93) is connected to one side of it. One end of the conductive rod (93) is fixedly connected to a sliding block (913) that contacts the contact block (95).

2. The method for improving the low-temperature cycle performance of lithium iron phosphate batteries according to claim 1, characterized in that, The modified materials include, but are not limited to, LiBF4-LiBOB mixed salt and lithium borate (LiODFB), the coating layer is made of metallic materials, and other compound particles are Mg particles or La ions.

3. The method for improving the low-temperature cycle performance of lithium iron phosphate batteries according to claim 1, characterized in that, The spraying mechanism (7) includes: The second rotating tube (78) is rotatably connected to the coating tube (6), and a second protective ring (70) is fixedly connected to its outer wall. The second limiting tube (79) is provided in multiple forms and is evenly fixed on the second rotating tube (78). The second limiting tube (79) is fixedly connected to the inside of the second spring (77), and the other end of the second spring (77) is fixedly connected to the extrusion rod (72) which is slidably sleeved with the second limiting tube (79). The extrusion rod (72) is slidably sleeved with the second protective ring (70), and one end of the extrusion rod (72) is rotatably connected to the rolling ring (71). The third limiting tube (74) is provided in multiple forms and is evenly fixed on the second rotating tube (78). A third spring (76) is fixedly connected inside the third limiting tube (74), and a feeding rod (73) that is slidably sleeved with the second limiting tube (79) is fixedly connected to the other end of the third spring (76). A connecting tube (75) is connected between the third limiting tube (74) and the second limiting tube (79). The feed hole is provided in multiple ways and is evenly arranged on the second limiting tube (79). One end of the feed rod (73) is located inside the feed hole.

4. The method for improving the low-temperature cycle performance of lithium iron phosphate batteries according to claim 3, characterized in that, The stabilizing mechanism (5) includes: The third rotating tube (55) is rotatably connected to the coating tube (6), and a third protective ring (50) is fixedly connected to its outer wall. Multiple heating tubes (53) are fixedly connected inside the third protective ring (50). The fourth limiting tube (52) is provided in multiple forms and is evenly fixed on the third rotating tube (55). A fourth spring (54) is fixedly connected inside the tube, and the other end of the fourth spring (54) is fixedly connected to a stabilizing tube (51) that is slidably sleeved with the fourth limiting tube (52). The stabilizing tube (51) is slidably sleeved with the third protective ring (50). The contact hole (56) is located inside the stabilizing tube (51), and one end of it is connected to the outside. The feed hole (57) is located on the third rotating tube (55), and there are multiple feed holes.

5. The method for improving the low-temperature cycle performance of lithium iron phosphate batteries according to claim 4, characterized in that, The reinforcement mechanism (3) includes a fourth rotating tube (31) rotatably connected to the stabilizing tube (4). A fourth protective ring (30) is fixedly connected to the outer wall of the fourth rotating tube (31), and a plurality of heating wires (32) are fixedly connected inside the fourth protective ring (30).

6. The method for improving the low-temperature cycle performance of lithium iron phosphate batteries according to claim 5, characterized in that, The circulation mechanism includes: The conveying pump (21) is fixedly connected to the bottom of the processing box (18), and its input end is connected to the suction pipe (19) connected to the receiving box (1). A central box (20) is located inside a processing box (18), and its top is connected to a vent pipe (22) that communicates with an impregnation box (16). The output end of the delivery pump (21) is connected to the central box (20). A retaining plate (24) is connected to a discharge pipe (8), the bottom of which is provided with multiple leakage holes, and the bottom of the retaining plate (24) is connected to a retaining pipe (23) connected to an impregnation tank (16). A blower (14) is fixedly connected to a feed pipe (15), with its input end extending into the feed pipe (15) and its output end connected to an air outlet pipe (13) connected to a purification box (12). The discharge pipe (10) is connected to the addition box (11) and extends to the impregnation box (16) at the other end. An electromagnetic flow control valve is connected to the discharge pipe (10).

7. An apparatus for improving the low-temperature cycle performance of lithium iron phosphate batteries, used in the method as described in claim 6, characterized in that, include: The battery box (40) has a protective plate (42) connected inside and a connecting box (44) connected to its top. The battery panel (41) is located inside the battery box (40), and circulation pipes (43) are fixedly connected to the battery box (40) on both sides of the battery panel (41), and the other end of the circulation pipe (43) extends into the connecting box (44); A circulating pump (410) is fixedly connected inside the connecting box (44), with its input end connected to a circulating pipe (43) on one side and its output end connected to a mixing pipe (48). The mixing chamber (46) has a storage cavity (49) inside, and the storage cavity (49) is connected to a guide pipe (47) connected to the mixing pipe (48). The return pipe (45) is connected at one end to the mixing pipe (48) and at the other end to the circulation pipe (43) on one side.

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