Lithium iron phosphate ion power battery structure

Abstract

The application relates to a lithium iron phosphate ion power battery structure for a cylindrical battery, which comprises a positive electrode structure, a winding core, a negative electrode structure and a shell; the positive electrode structure is arranged on the end face of one end of the winding core, the negative electrode structure is arranged on the end face of the other end of the winding core, the winding core is sleeved in the shell, and the negative electrode structure abuts against the inner surface of the bottom of the shell. The two ends of the winding core are rubbed flat to obtain positive and negative electrode lugs, so that the energy density of the battery can be effectively improved, the internal resistance of the winding core is reduced, and the cost is low. The positive and negative electrodes of the application adopt full lug structures, so that the electronic conduction path can be effectively shortened, the battery internal resistance is reduced, the heat dissipation effect is good during large-current charging and discharging, meanwhile, the traditional positive and negative lug welding and lug rubber coating processes are removed, and the production efficiency is effectively improved. The application has the advantages of simple structure, good sealing property, low cost, good reliability, simple production process and high production efficiency.

Description

Technical Field

[0001] This invention relates to the field of power battery technology, and in particular to a lithium iron phosphate power battery structure. Background Technology

[0002] Power batteries can be cylindrical, prismatic, or pouch cells. Cylindrical batteries have advantages such as high production efficiency, high degree of equipment automation, and good product performance consistency, making them increasingly popular. However, power batteries generate a large amount of heat during high-rate charging and discharging. When the heat dissipation rate cannot meet the requirements, the internal temperature of the battery will continue to rise, reducing the battery's cycle life and, in severe cases, causing thermal runaway and resulting in safety accidents.

[0003] Currently, most cylindrical power battery cells on the market use single-tab or multi-tab structures for their positive and negative electrodes. This makes it difficult to meet the heat dissipation requirements of batteries under high-current charging and discharging conditions. Problems include poor tab overcurrent capacity, uneven internal stress during battery cycling due to cell heating during high-current discharge, poor contact between the positive and negative electrode plates near the tabs leading to poor cycle life, long electron conduction paths, and high internal resistance. Furthermore, traditional tab installation processes involve welding and tab encapsulation, which are complex and have low production efficiency. Summary of the Invention

[0004] Based on this, the present invention provides a lithium iron phosphate power battery structure, which aims to solve problems such as poor overcurrent capacity of the tabs, uneven internal tension of the battery during cycling due to cell heating during high current discharge, poor battery cycle life due to loose contact between positive and negative electrode plates near the tabs, long electronic conduction path, and high internal resistance of the battery.

[0005] To achieve the above objectives, the embodiments of the present invention propose the following technical solutions:

[0006] A lithium iron phosphate power battery structure for cylindrical batteries includes a positive electrode structure, a core, a negative electrode structure, and a housing; the positive electrode structure is disposed on the end face of one end of the core, the negative electrode structure is disposed on the end face of the other end of the core, the core is sleeved inside the housing, and the negative electrode structure abuts against the inner surface of the bottom of the housing;

[0007] The positive electrode structure includes a cap, an explosion-proof sheet, a positive electrode connecting piece, a sealing ring, tape, a positive electrode tab, and an insulating gasket; the positive electrode tab is the end face of the winding core; the insulating gasket is disposed on the edge of the positive electrode tab away from the winding core; the tape is sleeved on one end of the winding core, and the tape abuts against the positive electrode tab and the insulating gasket respectively; the positive electrode connecting piece is welded to the side of the positive electrode tab away from the winding core; the explosion-proof sheet is welded to the side of the positive electrode connecting piece away from the positive electrode tab; the cap is disposed on the side of the explosion-proof sheet away from the positive electrode connecting piece; the sealing ring is sleeved on the edge of the cap, and the sealing ring abuts against the housing.

[0008] In a preferred embodiment, a circular protrusion is provided on the side of the positive electrode connecting piece near the positive electrode tab, and a plurality of first strip-shaped protrusions are evenly distributed on the side of the circular protrusion near the positive electrode tab. The positive electrode connecting piece is welded to the positive electrode tab through the first strip-shaped protrusions. This arrangement allows for better contact between the positive electrode connecting piece and the positive electrode tab, effectively preventing sparking during welding; it also significantly increases the rigidity of the positive electrode connecting piece and provides a better pre-compression effect on the positive electrode tab.

[0009] In a preferred embodiment, a fan-shaped surface is provided between adjacent first strip-shaped protrusions, and a plurality of through holes are provided on the fan-shaped surface. In this application, the through holes are mainly used for liquid discharge and venting.

[0010] In a preferred embodiment, a first circular hole is provided at the geometric center of the positive electrode connecting piece, and each of the first strip-shaped protrusions extends from the first circular hole toward the edge of the positive electrode connecting piece.

[0011] In a preferred embodiment, the positive electrode connecting piece, the circular protrusion, the first strip protrusion, the fan-shaped surface, the through hole, and the first circular hole are integrally formed.

[0012] In a preferred embodiment, the inner surface of the tape abuts against the outer periphery of the positive electrode tab and the outer periphery of the insulating gasket, respectively. This secures the insulating gasket with the tape and effectively prevents displacement of the insulating gasket during the rolling process, thus avoiding a short circuit in the winding core.

[0013] In a preferred embodiment, the edge of the cap is evenly provided with multiple vent holes. In this application, the cap serves as the output end of the positive electrode structure, acting as a seal and venting point. The sealing ring effectively ensures insulation between the positive and negative electrode structures while sealing the opening.

[0014] In a preferred embodiment, the internal pressure of the explosion-proof plate is ≥18Kg. Opening the explosion-proof valve can release pressure. At the same time, the explosion-proof plate is welded to the positive electrode connection piece, serving the functions of sealing and current flow.

[0015] In a preferred embodiment, the negative electrode structure includes a negative electrode tab and a negative electrode connecting piece, wherein the negative electrode tab is the end face of the winding core; the negative electrode connecting piece is welded to the side of the negative electrode tab away from the winding core; and the negative electrode connecting piece abuts against the inner surface of the bottom of the housing.

[0016] In a preferred embodiment, the negative electrode connecting piece has a plurality of second strip-shaped protrusions evenly arranged on the side near the negative electrode tab, and a fan-shaped groove is provided between two adjacent second strip-shaped protrusions; the negative electrode connecting piece is welded to the negative electrode tab through the second strip-shaped protrusions, and the negative electrode connecting piece abuts against the inner surface of the bottom of the housing through the fan-shaped groove.

[0017] In a preferred embodiment, a second circular hole is provided at the geometric center of the negative electrode connecting piece, and each of the second strip-shaped protrusions extends from the second circular hole toward the edge of the negative electrode connecting piece.

[0018] By setting a second strip-shaped protrusion and a fan-shaped groove on the side of the negative electrode connector near the core, the rigidity of the negative electrode connector can be greatly increased, and the negative electrode tab can be pre-compressed effectively, thus reducing contact resistance. At the same time, the internal space of the battery can be fully utilized, which can effectively increase the energy density and volume density of the battery.

[0019] In a preferred embodiment, the core is a core obtained by winding the positive and negative electrode sheets using a winding structure; the positive electrode tab is a tab obtained by flattening the positive end of the core using a flattening process; the negative electrode tab is a tab obtained by flattening the negative end of the core using a flattening process; and both the positive electrode connecting piece and the negative electrode connecting piece are connecting pieces obtained by a stamping process.

[0020] In this application, the positive electrode tab and the positive electrode connecting piece, the positive electrode connecting piece and the explosion-proof piece, the negative electrode tab and the negative electrode connecting piece, and the negative electrode connecting piece and the bottom of the casing all have a large welding cross section and low resistance, which can carry a large current. Therefore, the battery using the structure of this application has the ability to carry a large rate current with low physical resistance, while ensuring the sealing and reliability of the battery structure.

[0021] In a preferred embodiment, the cap is made of nickel-plated steel strip; the positive electrode connecting piece is made of aluminum; the explosion-proof piece is made of aluminum; the housing is made of nickel-plated steel; and the negative electrode connecting piece is made of copper or nickel.

[0022] The beneficial effects achieved by this invention are as follows: Both the positive and negative electrodes of this application adopt a full-tab structure, which can effectively shorten the electron conduction path, reduce the internal resistance of the battery, and improve the problem of cell heating caused by high-current discharge, resulting in good heat dissipation during high-current charging and discharging. Simultaneously, it eliminates the traditional processes of welding the positive and negative tabs and wrapping the tabs with adhesive, improving production efficiency. By flattening both ends of the wound core to obtain the positive and negative tabs, it can replace the single-tab or multi-tab structure of traditional cylindrical batteries currently on the market, effectively improving the battery's energy density, reducing the internal resistance of the cell, and lowering the cost (eliminating the need for positive and negative tabs, high-temperature tape, welding the tabs, and applying adhesive to the tabs). The structure of this application does not require welding the positive and negative tabs, resulting in a high battery assembly ratio and ensuring the flatness of the positive and negative electrode sheets inside the cell, leading to higher production efficiency compared to traditional manufacturing processes. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 This is an exploded structural diagram of a lithium iron phosphate power battery structure according to an embodiment of the present invention;

[0025] Figure 2 for Figure 1 A schematic diagram of the core structure of a lithium iron phosphate power battery;

[0026] Figure 3 for Figure 1 A schematic diagram of the positive electrode connector of a lithium iron phosphate power battery.

[0027] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, top, bottom, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0030] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0031] It should be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0032] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0033] Currently, most cylindrical power battery cells on the market use single-tab or multi-tab structures for their positive and negative electrodes, which makes it difficult to meet the heat dissipation requirements of batteries under high-current charging and discharging conditions. This results in problems such as poor tab overcurrent capacity, uneven internal stress during battery cycling due to cell heating during high-current discharge, poor contact between the positive and negative electrode plates near the tabs leading to poor cycle life, long electron conduction paths, and high internal resistance. Furthermore, traditional installation processes for the positive and negative tabs involve welding and tab encapsulation, which are complex and have low production efficiency. Therefore, this invention provides a lithium iron phosphate power battery structure to solve the above-mentioned technical problems. This application features a simple structure, good sealing, low cost, and good reliability. Both the positive and negative electrodes use a full-tab structure, which effectively shortens the electron conduction path, reduces battery internal resistance, and improves cell heating during high-current discharge. The manufacturing process is simple and has high production efficiency.

[0034] Specifically, such as Figures 1 to 3 As shown, this embodiment of the invention provides a lithium iron phosphate power battery structure for a cylindrical battery, including a positive electrode structure 10, a core 20, a negative electrode structure 30, and a housing 40; the positive electrode structure 10 is disposed on the end face of one end of the core 20, the negative electrode structure 30 is disposed on the end face of the other end of the core 20, the core 20 is sleeved inside the housing 40, and the negative electrode structure 30 abuts against the inner surface of the bottom of the housing 40;

[0035] The positive electrode structure 10 includes a cap 11, an explosion-proof sheet 12, a positive electrode connecting piece 13, a sealing ring 14, tape 15, a positive electrode tab 16, and an insulating gasket 17. The positive electrode tab 16 is the end face of the winding core 20. The insulating gasket 17 is disposed on the edge of the positive electrode tab 16 away from the winding core 20. The tape 15 is sleeved on one end of the winding core 20, and the tape 15 abuts against the positive electrode tab 16 and the insulating gasket 17 respectively. The positive electrode connecting piece 13 is welded to the side of the positive electrode tab 16 away from the winding core 20. The explosion-proof sheet 12 is welded to the side of the positive electrode connecting piece 13 away from the positive electrode tab 16. The cap 11 is disposed on the side of the explosion-proof sheet 12 away from the positive electrode connecting piece 13. The sealing ring 14 is sleeved on the edge of the cap 11, and the sealing ring 14 abuts against the housing 40.

[0036] In a preferred embodiment, the positive electrode connecting piece 13 has a circular protrusion 131 on its side near the positive electrode tab 16, and a plurality of first strip-shaped protrusions 132 are evenly distributed on the side of the circular protrusion 131 near the positive electrode tab 16. The positive electrode connecting piece 13 is welded to the positive electrode tab 16 through the first strip-shaped protrusions 132. This arrangement allows for better contact between the positive electrode connecting piece 13 and the positive electrode tab 16, effectively preventing sparking during welding; it also significantly increases the rigidity of the positive electrode connecting piece 13 and provides a better pre-compression effect on the positive electrode tab 16.

[0037] In a preferred embodiment, a fan-shaped surface 133 is provided between adjacent first strip-shaped protrusions 132, and a plurality of through holes 134 are provided on the fan-shaped surface 133. In this application, the through holes 134 are mainly used for liquid discharge and venting.

[0038] In a preferred embodiment, a first circular hole 135 is provided at the geometric center of the positive electrode connecting piece 13, and each of the first strip-shaped protrusions 132 extends from the first circular hole 135 toward the edge of the positive electrode connecting piece 13. In this way, the rigidity of the positive electrode connecting piece 13 can be well guaranteed.

[0039] In a preferred embodiment, the positive electrode connecting piece 13, the circular protrusion 131, the first strip-shaped protrusion 132, the fan-shaped surface 133, the through hole 134, and the first circular hole 135 are integrally formed. This makes the entire positive electrode structure 10 compact and space-efficient.

[0040] In this embodiment, the thickness of the first strip-shaped protrusion 132 is preferably 3mm to 5mm. This makes the entire positive electrode structure 10 compact, with high space utilization, saving raw material costs and effectively reducing production costs.

[0041] In a preferred embodiment, the inner surface of the tape 15 abuts against the outer periphery of the positive electrode tab 16 and the outer periphery of the insulating pad 17, respectively. This secures the insulating pad 17 with the tape 15 and effectively prevents displacement of the insulating pad 17 during the rolling process, thus avoiding a short circuit in the core 20.

[0042] In a preferred embodiment, the edge of the cap 11 is evenly provided with a plurality of vent holes 111. In this application, the cap 11 serves as the output end of the positive electrode structure 10, and can function as a seal and a top vent. The sealing ring 14, while sealing the opening, can effectively ensure the insulation between the positive electrode structure 10 and the negative electrode structure 30.

[0043] In a preferred embodiment, the internal pressure of the explosion-proof plate 12 is ≥18Kg. Opening the explosion-proof valve can release pressure. At the same time, the explosion-proof plate 12 is welded to the positive electrode connection piece 13, which serves to seal and facilitate current flow.

[0044] In a preferred embodiment, the negative electrode structure 30 includes a negative electrode tab 31 and a negative electrode connecting piece 32. The negative electrode tab 31 is the end face of the winding core 20. The negative electrode connecting piece 32 is welded to the side of the negative electrode tab 31 away from the winding core 20. The negative electrode connecting piece 32 abuts against the inner surface of the bottom of the housing 40.

[0045] In a preferred embodiment, the negative electrode connecting piece 32 has a plurality of second strip-shaped protrusions 321 evenly arranged on the side near the negative electrode tab 31, and a fan-shaped groove 322 is provided between two adjacent second strip-shaped protrusions 321; the negative electrode connecting piece 32 is welded to the negative electrode tab 31 through the second strip-shaped protrusions 321, and the negative electrode connecting piece 32 abuts against the inner surface of the bottom of the housing 40 through the fan-shaped groove 322.

[0046] In a preferred embodiment, a second circular hole 323 is provided at the geometric center of the negative electrode connecting piece 32, and each of the second strip-shaped protrusions 321 extends from the second circular hole 323 toward the edge of the negative electrode connecting piece 32.

[0047] By setting a second strip-shaped protrusion 321 and a fan-shaped groove 322 on the side of the negative electrode connecting piece 32 near the core 20, the rigidity of the negative electrode connecting piece 32 can be greatly increased, and the negative electrode tab 31 can be pre-pressed effectively, thus reducing the contact resistance. At the same time, the internal space of the battery can be fully utilized, which can effectively increase the energy density and volume density of the battery.

[0048] In a preferred embodiment, the sum of the areas of the second strip-shaped protrusions 321 is less than the sum of the areas of the fan-shaped grooves 322. This allows for full utilization of the battery's internal space, effectively increasing the battery's energy density and volumetric density.

[0049] In a preferred embodiment, the core 20 is a core obtained by winding the positive and negative electrode sheets using a winding structure; the positive electrode tab 16 is a tab obtained by flattening the positive end of the core 20 using a flattening process; the negative electrode tab 31 is a tab obtained by flattening the negative end of the core 20 using a flattening process; the positive electrode connecting piece 13 and the negative electrode connecting piece 32 are both connecting pieces obtained by a stamping process.

[0050] In this application, the positive electrode tab 16 and the positive electrode connecting piece 13, the positive electrode connecting piece 13 and the explosion-proof piece 12, the negative electrode tab 31 and the negative electrode connecting piece 32, and the negative electrode connecting piece 32 and the bottom of the casing 40 all have a large welding cross section and low resistance, which can carry a large current. Therefore, the battery using the structure of this application has the ability to have low physical resistance and carry a large rate current, while ensuring the sealing and reliability of the battery structure.

[0051] In a preferred embodiment, the cap 11 is a cap made of nickel-plated steel strip; the positive electrode connecting piece 13 is a connecting piece made of aluminum; the explosion-proof piece 12 is an explosion-proof piece made of aluminum; the housing 40 is a nickel-plated steel housing; and the negative electrode connecting piece 32 is a connecting piece made of copper or nickel.

[0052] This application employs a full-tab structure for both positive and negative electrodes, effectively shortening the electron conduction path, reducing battery internal resistance, and mitigating the overheating issue caused by high-current discharge. It also provides excellent heat dissipation during high-current charging and discharging. Furthermore, it eliminates the traditional processes of welding and encapsulating the positive and negative electrodes, improving production efficiency. By flattening both ends of the wound core to obtain the positive and negative electrodes, this method can replace the single-tab or multi-tab structure of traditional cylindrical batteries currently on the market, effectively increasing battery energy density, reducing cell internal resistance, and lowering costs (eliminating the need for positive and negative electrodes, high-temperature tape, welding, and adhesive bonding processes). The structure of this application eliminates the need for welding the positive and negative electrodes, resulting in a high battery assembly ratio and ensuring the flatness of the positive and negative electrode sheets inside the cell, leading to higher production efficiency compared to traditional manufacturing processes.

[0053] In this embodiment, the negative electrode connecting piece 32 is uniformly provided with six second strip-shaped protrusions 321 and six fan-shaped grooves 322, with the second strip-shaped protrusions 321 and the fan-shaped grooves 322 spaced apart. By providing the second strip-shaped protrusions 321 and fan-shaped grooves 322 on the side of the negative electrode connecting piece 32 near the core 20, the rigidity of the negative electrode connecting piece 32 can be significantly increased, and a better pre-compression effect can be achieved on the negative electrode tab 31, effectively reducing contact resistance; at the same time, the internal space of the battery can be fully utilized, effectively increasing the energy density and volume density of the battery.

[0054] The present invention employs a full-tab structure for both positive and negative electrodes. The negative electrode tab is directly connected (welded) to the negative electrode connecting piece, the negative electrode connecting piece is connected (welded) to the housing, the positive electrode tab is directly connected (welded) to the positive electrode connecting piece, and the positive electrode connecting piece is directly connected (welded) to the explosion-proof sheet. This shortens the electron conduction path, reduces the battery's internal resistance, and improves the problem of cell heating during high-current discharge. Furthermore, by setting strip-shaped protrusions and fan-shaped grooves on the negative electrode connecting piece, connecting the negative electrode tab through the strip-shaped protrusions and the bottom of the housing through the fan-shaped grooves, the rigidity of the negative electrode connecting piece can be significantly increased, and a better pre-compression effect can be achieved on the negative electrode tab, effectively reducing contact resistance. At the same time, it can fully utilize the internal space of the battery, effectively increasing the battery's energy density and volumetric density. By setting circular and strip-shaped protrusions on the positive electrode connecting piece and connecting the positive electrode tab through the strip-shaped protrusion, the rigidity of the positive electrode connecting piece can be greatly increased, and the positive electrode tab can be pre-compressed effectively, thus reducing contact resistance. At the same time, the internal space of the battery can be fully utilized, which can effectively increase the energy density and volume density of the battery. This application has a simple structure, good sealing performance, low cost, and good reliability. It can effectively solve problems such as poor overcurrent capacity of power battery tabs, uneven internal tension of the battery during cycling due to cell heating during high current discharge, poor battery cycle life due to loose contact of the electrode pieces near the tab, long electronic conduction path, and high internal resistance of the battery.

[0055] In the description of this specification, references to terms such as "an embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0056] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0057] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A lithium iron phosphate power battery structure, characterized in that, For use in cylindrical batteries, including a positive electrode structure, a core, a negative electrode structure, and a housing; the positive electrode structure is disposed on the end face of one end of the core, the negative electrode structure is disposed on the end face of the other end of the core, the core is sleeved inside the housing, and the negative electrode structure abuts against the inner surface of the bottom of the housing; The positive electrode structure includes a cap, an explosion-proof sheet, a positive electrode connecting piece, a sealing ring, tape, a positive electrode tab, and an insulating gasket; the positive electrode tab is the end face of the winding core; the insulating gasket is disposed on the edge of the positive electrode tab away from the winding core; the tape is sleeved on one end of the winding core, and the tape abuts against the positive electrode tab and the insulating gasket respectively; the positive electrode connecting piece is welded to the side of the positive electrode tab away from the winding core; the explosion-proof sheet is welded to the side of the positive electrode connecting piece away from the positive electrode tab; the cap is disposed on the side of the explosion-proof sheet away from the positive electrode connecting piece; the sealing ring is sleeved on the edge of the cap, and the sealing ring abuts against the housing; A circular protrusion is provided on the side of the positive electrode connecting piece near the positive electrode tab, and a plurality of first strip-shaped protrusions are evenly provided on the side of the circular protrusion near the positive electrode tab. The positive electrode connecting piece is welded to the positive electrode tab through the first strip-shaped protrusions. A fan-shaped surface is provided between adjacent first strip-shaped protrusions, and multiple through holes are provided on the fan-shaped surface; A first circular hole is provided at the geometric center of the positive electrode connecting piece, and each of the first strip-shaped protrusions extends from the first circular hole toward the edge of the positive electrode connecting piece; The negative electrode structure includes a negative electrode tab and a negative electrode connecting piece. The negative electrode tab is the end face of the winding core. The negative electrode connecting piece is welded to the side of the negative electrode tab away from the winding core. The negative electrode connecting piece abuts against the inner surface of the bottom of the housing. The negative electrode connecting piece has a plurality of second strip-shaped protrusions evenly arranged on the side near the negative electrode tab, and a fan-shaped groove is provided between two adjacent second strip-shaped protrusions; the negative electrode connecting piece is welded to the negative electrode tab through the second strip-shaped protrusions, and the negative electrode connecting piece abuts against the inner surface of the bottom of the housing through the fan-shaped groove; Both the positive and negative electrodes adopt a full-tab structure; The positive electrode tab is obtained by flattening the positive end of the core using a flattening process; the negative electrode tab is obtained by flattening the negative end of the core using a flattening process.

2. The lithium iron phosphate power battery structure according to claim 1, characterized in that, The positive electrode connector, the circular protrusion, the first strip protrusion, the fan-shaped surface, the through hole, and the first circular hole are integrally formed.

3. The lithium iron phosphate power battery structure according to claim 2, characterized in that, The inner surface of the tape abuts against the outer periphery of the positive electrode tab and the outer periphery of the insulating pad, respectively.

4. The lithium iron phosphate power battery structure according to claim 1, characterized in that, The edge of the cap is evenly provided with multiple vent holes; the internal pressure of the explosion-proof sheet is ≥18Kg.

5. The lithium iron phosphate power battery structure according to claim 1, characterized in that, A second circular hole is provided at the geometric center of the negative electrode connecting piece, and each of the second strip-shaped protrusions extends from the second circular hole toward the edge of the negative electrode connecting piece.

6. The lithium iron phosphate power battery structure according to claim 1, characterized in that, The core is a core obtained by winding the positive and negative electrode sheets using a winding structure; the positive electrode connecting piece and the negative electrode connecting piece are both connecting pieces obtained by stamping process.

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