A battery and an electric device

Abstract

The application belongs to the technical field of battery preparation, and particularly relates to a battery and an electric device. The battery comprises a shell, a roll core arranged in the shell, and a columnar body arranged at the center of the roll core. The columnar body contains a flame retardant. Along the length direction of the columnar body, the columnar body has a first column segment, a third column segment, and a second column segment arranged between the first column segment and the third column segment. The first column segment, the second column segment, and the third column segment contain the flame retardant. The content of the flame retardant in the second column segment is less than the content of the flame retardant in the first column segment and the third column segment. The columnar body has low content of the flame retardant in the middle, realizes lightweight and low cost, the columnar body has high content of the flame retardant at both ends, is more targeted and efficient for the flame retardation of the tab with high temperature, and fully utilizes the internal empty space of the roll core, which is beneficial to improving the safety performance, and improving the electrochemical performance and high energy density of the battery.

Description

Technical Field

[0001] This invention belongs to the field of battery manufacturing technology, specifically relating to a battery and an electrical device. Background Technology

[0002] Traditional cylindrical batteries still have insufficient safety, with issues such as overheating, fire, and even explosions occurring during use. Furthermore, the hollow space within the cylindrical battery is not fully utilized, resulting in wasted space and hindering improvements in overall battery performance and energy density. Additionally, poor winding force during electrode winding leads to poor contact at the positive and negative electrode interfaces, affecting the battery's charge / discharge performance and cycle life, and reducing battery reliability and stability. Summary of the Invention

[0003] Therefore, the main objective of this application is to provide a battery and electrical device to solve the problems of insufficient safety and underutilization of the hollow space in existing conventional cylindrical batteries.

[0004] Therefore, this application provides the following technical solution.

[0005] This application provides a battery comprising a housing and a core disposed within the housing. A columnar body is disposed at the center of the core, and the columnar body contains a flame retardant. Along the length direction of the columnar body, the columnar body has a first columnar segment, a third columnar segment, and a second columnar segment disposed between the first columnar segment and the third columnar segment. The first columnar segment, the second columnar segment, and the third columnar segment contain the flame retardant.

[0006] The flame retardant content in the second column segment is less than the flame retardant content in the first column segment and the third column segment.

[0007] Furthermore, the ratio of the lengths of the first column segment, the second column segment, and the third column segment is (1-2):1:(1-2).

[0008] Furthermore, based on the total mass of the flame retardant in the columnar body being 100%, the flame retardant content in the first columnar section is 35-50 wt%; the flame retardant content in the second columnar section is 5-20 wt%; and the flame retardant content in the third columnar section is 35-50 wt%.

[0009] Furthermore, the flame retardant particles have particle sizes Dv10 of 5-10 μm, Dv50 of 10-50 μm, and Dv99 of 50-90 μm; and / or,

[0010] The flame retardant includes at least one of polyphosphazene, ammonium polyphosphate, phosphate, red phosphorus, and organophosphorus compounds.

[0011] Furthermore, the length ratio of the columnar body to the core is (91-98):100.

[0012] Furthermore, the columnar body also includes a polymeric hot-melt material, and the first column segment, the second column segment, and the third column segment contain the polymeric hot-melt material.

[0013] Furthermore, the polymeric hot-melt material includes at least one of EVA (ethylene-vinyl acetate copolymer), POE (ethylene-butene polymer), PEO (ethylene oxide), and PCL (polycaprolactone).

[0014] Furthermore, the shell is cylindrical; and / or the columnar body is cylindrical.

[0015] Furthermore, the bonding strength between the interior of the core and the columnar body is 12-30 N / cm.

[0016] This application also provides an electrical device including the aforementioned battery.

[0017] The technical solution of this application has the following advantages:

[0018] This application presents a cylindrical structure at the center of the battery core, containing a flame retardant. Along the length of the cylindrical structure, the flame retardant content in the center is lower than at both ends, resulting in a low-weight and low-cost design. The higher flame retardant content at the ends provides targeted and efficient protection at the higher-temperature tabs, improving overall battery performance and safety. Furthermore, it fully utilizes the internal space of the cylindrical battery, contributing to improved overall performance, high energy density, and enhanced safety. When the battery temperature is too high, the flame retardant in the cylindrical structure absorbs heat, lowering the battery temperature. The resulting product adheres to the positive and negative electrode tabs, providing flame retardancy. The inner ring of the battery core dissipates heat slowly and has a higher temperature; when the battery temperature becomes too high, the cylindrical structure can promptly cool and retard the flame at the inner ring, thus reducing the risk of overheating and fire, and improving battery safety. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of the battery in Embodiment 1 of the present invention;

[0021] Figure label:

[0022] 1-Columnar body; 2-Shell;

[0023] 11 - First column segment; 12 - Second column segment; 13 - Third column segment. Detailed Implementation

[0024] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0025] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0026] As analyzed in the background section, the safety of traditional cylindrical batteries remains insufficient, with issues such as overheating, fire, and even explosions occurring during use. Furthermore, the hollow space within the cylindrical battery is not fully utilized, resulting in wasted space and negatively impacting overall battery performance and energy density. Additionally, during the winding process, poor winding force leads to poor contact between the positive and negative electrode interfaces, affecting battery performance.

[0027] To address the aforementioned problems, this application provides a battery comprising a casing and a core disposed within the casing. A columnar body is disposed at the center of the core, and the columnar body contains a flame retardant. Along the length of the columnar body, the columnar body has a first segment, a third segment, and a second segment disposed between the first segment and the third segment. The first segment, the second segment, and the third segment all contain the flame retardant. The flame retardant content in the second segment is less than the flame retardant content in the first segment and the third segment.

[0028] This application presents a battery core with a cylindrical structure at its center. This cylindrical structure contains a flame retardant, and the flame retardant content at the center is lower than at the ends. The lower flame retardant content in the middle of the cylindrical structure results in lighter weight and lower cost, while the higher flame retardant content at the ends provides more targeted and efficient protection at the higher-temperature tabs, improving the overall performance and safety of the battery. Furthermore, it fully utilizes the internal space of the cylindrical battery, which is beneficial for improving overall battery performance, maintaining high energy density, and enhancing safety. When the battery temperature is too high, the flame retardant in the cylindrical structure absorbs heat, lowering the battery temperature. The resulting product adheres to the positive and negative electrode tabs, providing flame retardancy. The inner ring of the battery core dissipates heat slowly and has a higher temperature. When the battery temperature is too high, the cylindrical structure can promptly cool and retard the flame at the inner ring of the core, thereby reducing the risk of overheating and fire, and improving battery safety. The core described in this application is formed by sequentially stacking and winding a positive electrode sheet, a separator, and a negative electrode sheet. The battery includes the core, electrolyte, and casing.

[0029] In addition, the columnar body can also support the core, maintain good winding force, improve the interface contact between the positive and negative electrode sheets, and avoid poor interface contact between the positive and negative electrode sheets due to poor winding force, which would affect the charge and discharge performance and cycle life of the battery; at the same time, it can also improve the reliability and stability of the battery.

[0030] In some embodiments, the length ratio of the first column segment, the second column segment, and the third column segment is (1-2):1:(1-2). In this application, the second column segment is located at the very center of the hollow structure in the core, and the lengths of the first and third column segments are not shorter than the second column segment. This makes the first and third column segments key segments for the columnar body to exert its flame-retardant effect. Controlling the length of the second column segment can also appropriately reduce the amount of flame retardant used in the length direction, achieving a low-cost and lightweight effect. This application's adjustment of the length ratio of the three column segments allows the columnar body to achieve a low-cost and lightweight effect without affecting the flame-retardant effect. It should be noted that the lengths of the first and third column segments can be the same or different.

[0031] In some embodiments, based on the total mass of flame retardant in the columnar body as 100%, the flame retardant content in the first column segment is 35-50 wt%; the flame retardant content in the second column segment is 5-20 wt%; and the flame retardant content in the third column segment is 35-50 wt%. In this application, the flame retardant content in the first and third column segments is higher than that in the second column segment, meaning the flame retardant content at both ends of the columnar body is high. This ensures that the first and third column segments play a major flame-retardant role. The lower flame retardant content in the second column segment allows for a suitable reduction in the amount of flame retardant used from the perspective of columnar body content, achieving a low-cost and lightweight effect. It should be noted that the flame retardant content in the first and third column segments can be the same or different, and the types of flame retardants can be the same or different.

[0032] In some embodiments, the columnar body further includes a polymeric hot-melt material, and the first columnar segment, the second columnar segment, and the third columnar segment contain the polymeric hot-melt material. The polymeric hot-melt material includes at least one of EVA (ethylene-vinyl acetate copolymer), POE (ethylene-butene polymer), PEO (ethylene oxide), and PCL (polycaprolactone). The columnar body of this application includes a polymeric hot-melt material, which on the one hand can encapsulate the flame retardant, protecting it from electrolyte corrosion and preventing the flame retardant from entering the electrolyte and affecting battery performance; on the other hand, it can make the bond between the columnar body and the core more compact, allowing the columnar body to provide support and maintaining good tension in the core.

[0033] In some embodiments, the particle size of the flame retardant particles is Dv10 of 5-10 μm, Dv50 of 10-50 μm, and Dv99 of 50-90 μm; and / or,

[0034] The flame retardant includes at least one of polyphosphazene, ammonium polyphosphate, phosphate, red phosphorus, and organophosphorus compounds.

[0035] To protect the flame retardant from electrolyte corrosion and ensure a tight bond between the columnar structure and the core, a polymeric hot-melt material is typically added to the columnar structure. In this application, the flame retardant particles in the columnar structure are distributed within the aforementioned range, allowing large flame retardant particles to be easily exposed and released after the polymeric hot-melt material encapsulating the flame retardant melts upon heating, thus exerting its flame-retardant effect. Phosphate-based flame retardants may be, but are not limited to, at least one of zirconium phosphate, calcium phosphate, and zinc phosphate; organophosphorus flame retardants may be, but are not limited to, at least one of guanidine phosphonate, phosphate esters, and phosphite esters. When the core temperature is too high, these flame retardants can absorb heat, lowering the battery temperature. The resulting thermal decomposition products can adhere to the electrode surface, providing excellent flame retardancy and effectively improving battery safety.

[0036] Considering the swelling phenomenon of polymer materials in the electrolyte, in some embodiments, the length ratio of the column to the core is (91-98):100. This can prevent the column from swelling too long in the electrolyte and pressing against the tabs, thus affecting the current carrying capacity of the tabs and the electrochemical performance of the battery.

[0037] In some embodiments of the battery, the first column comprises a polymeric hot-melt material and a flame retardant in a mass ratio of (52.5-60):(40-47.5); the second column comprises a polymeric hot-melt material and a flame retardant in a mass ratio of (60-95):(5-40); and the third column comprises a polymeric hot-melt material and a flame retardant in a mass ratio of (52.5-60):(40-47.5). This application controls the amount of polymeric hot-melt material and flame retardant in the three columns, so that the flame retardant content in the second column, located in the middle section, is lower than that in the first and third columns. This ensures that the first and third columns play a major flame-retardant role while appropriately reducing the mass of the flame retardant, achieving a low-cost and lightweight effect. It should be noted that the types of flame retardants, polymeric hot-melt materials, and the mass ratio of flame retardant to polymeric hot-melt material in the first and third columns can be the same or different.

[0038] In some embodiments, the housing is cylindrical; and / or the column is cylindrical.

[0039] In some embodiments, the bond strength between the interior of the core and the column is 12-30 N / cm. The bond strength between the interior of the core and the column is obtained by methods known in the art, such as a 180° T-shaped peel.

[0040] In another embodiment of this application, a method for preparing the above-mentioned battery is provided, comprising:

[0041] (1) After the polymer hot melt material is melted, a flame retardant is added and stirred evenly to prepare polymer hot melt liquids corresponding to the first column segment, the second column segment and the third column segment respectively.

[0042] (2) After the core is wound, the polymer hot melt liquid corresponding to the second column segment is injected into the center of the hollow structure in the middle of the core, and then the polymer hot melt liquid corresponding to the first column segment and the third column segment is injected into both ends of the hollow structure in the middle of the core.

[0043] (3) Cooling and solidification form a columnar body with three segments; the columnar body is bonded to the core, with a tight internal connection. The columnar body also provides support, maintaining good winding force when the core is wound up, ensuring good interfacial contact and dynamics between the positive and negative electrode sheets, thereby improving the long-cycle performance of the battery. This invention uses a two-stage injection process to inject the polymer hot-melt liquid into the hollow structure in the middle of the core, making the preparation process simpler and faster.

[0044] Example 1

[0045] This embodiment provides a battery with the following structure: Figure 1As shown, the device includes a cylindrical shell 2 and a core disposed within the shell. The core comprises a positive electrode sheet, a separator, and a negative electrode sheet that are sequentially stacked and wound. A cylindrical column 1 is disposed at the center of the core, and the length ratio of the column 1 to the core is 95:100. The column 1 comprises a first column segment 11, a second column segment 12, and a third column segment 13 with a length ratio of 1:1:1. The second column segment 12 is disposed between the first column segment 11 and the third column segment 13. The bonding strength between the interior of the core and the column 13 is 29 N / cm.

[0046] Based on the total mass percentage of all flame retardants being 100%, the flame retardant content in the first column section is 40.9%; the flame retardant content in the second column section is 18.2%; and the flame retardant content in the third column section is 40.9%.

[0047] The first column section consists of EVA and polyphosphazene in a mass ratio of 6:4, with the polyphosphazene particles having a particle size of Dv10 of 9 μm, Dv50 of 45 μm, and Dv99 of 80 μm; the second column section consists of EVA and polyphosphazene in a mass ratio of 8:2, with the polyphosphazene particles having a particle size of Dv10 of 9 μm, Dv50 of 45 μm, and Dv99 of 80 μm; the third column section consists of EVA and polyphosphazene in a mass ratio of 6:4, with the polyphosphazene particles having a particle size of Dv10 of 9 μm, Dv50 of 45 μm, and Dv99 of 80 μm.

[0048] The above-mentioned battery preparation method includes:

[0049] 1) The preparation method of the positive electrode sheet includes: dispersing the positive active material (molecular formula: LiFePO4) with the conductive agent carbon nanotubes and the binder PVDF in a mass ratio of 96:2:2 in the solvent NMP and mixing them evenly to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated on the positive current collector aluminum foil, and after baking, cold pressing and cutting, the positive electrode sheet is obtained.

[0050] 2) The preparation method of the negative electrode sheet includes: dispersing artificial graphite, conductive carbon black SP and binder SBR in a mass ratio of 94:3:3 in deionized water and mixing them evenly to obtain a negative electrode slurry. The negative electrode slurry is evenly coated on the negative electrode current collector copper foil, and after baking, cold pressing and cutting, the negative electrode sheet is obtained.

[0051] 3) The electrolyte preparation method includes: mixing ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) in a mass ratio of 1:1:1 to obtain an organic solvent. LiPF6 is dissolved in the above organic solvent and mixed thoroughly to obtain the electrolyte. Based on the mass of the electrolyte, the mass percentage content of LiPF6 is 13%.

[0052] 4) The positive electrode sheet, PP / PE / PP composite separator, and negative electrode sheet are stacked and wound in sequence to obtain a core. Then, 60 parts by weight of EVA and 40 parts by weight of polyphosphazene are weighed. The EVA is heated to melt, and then the polyphosphazene is added and mixed evenly to obtain a polymeric hot-melt liquid, which serves as the raw material for the first column segment. The raw material for the third column segment is the same as that for the first column segment. 80 parts by weight of EVA and 20 parts by weight of polyphosphazene are weighed. The EVA is heated to melt, and then the polyphosphazene is added and mixed evenly to obtain a polymeric hot-melt liquid, which serves as the raw material for the second column segment. First, the polymeric hot-melt liquid corresponding to the second column segment is injected into the middle of the hollow structure in the core. Then, the polymeric hot-melt liquid corresponding to the first and third column segments is simultaneously injected into both ends of the hollow structure in the core. After cooling and solidification, a columnar body with the first, second, and third column segments is formed, which is bonded to the core. The core is placed into a cylindrical aluminum shell for welding and baking. After adding the electrolyte mentioned above, it is sealed to complete the battery preparation.

[0053] Example 2

[0054] This embodiment provides a battery that differs from Embodiment 1 in that the length ratio of the first, second, and third column segments in this embodiment is 1.5:1:1.5, the flame retardant content in the first column segment is 43wt%, the flame retardant content in the second column segment is 14wt%, and the flame retardant content in the third column segment is 43wt%.

[0055] Example 3

[0056] This embodiment provides a battery that differs from Embodiment 1 in that the length ratio of the first, second, and third column segments in this embodiment is 2:1:2, the flame retardant content in the first column segment is 44.4 wt%, the flame retardant content in the second column segment is 11.2 wt%, and the flame retardant content in the third column segment is 44.4 wt%.

[0057] Example 4

[0058] This embodiment provides a battery that differs from Embodiment 1 in that: the length ratio of the first column, the second column, and the third column in this embodiment is 1.5:1:2; the flame retardant content in the first column is 37.5 wt%; the flame retardant content in the second column is 12.5 wt%; and the flame retardant content in the third column is 50 wt%.

[0059] Example 5

[0060] This embodiment provides a battery that differs from Embodiment 1 in that the length ratio of the first, second, and third column segments in this embodiment is 2:1:1.5, the flame retardant content in the first column segment is 50 wt%, the flame retardant content in the second column segment is 12.5 wt%, and the flame retardant content in the third column segment is 37.5 wt%.

[0061] Example 6

[0062] This embodiment provides a battery, which differs from Embodiment 1 in that the length ratio of the cylindrical body to the winding core is 91:100.

[0063] Example 7

[0064] This embodiment provides a battery, which differs from Embodiment 1 in that the length ratio of the cylindrical body to the winding core is 98:100.

[0065] Example 8

[0066] This embodiment provides a battery that differs from Embodiment 1 in that: the first column comprises EVA and polyphosphazene in a mass ratio of 53:47, the second column comprises EVA and polyphosphazene in a mass ratio of 94:6, and the third column comprises EVA and polyphosphazene in a mass ratio of 53:47. The flame retardant content in the first column is 47 wt%, the flame retardant content in the second column is 6 wt%, and the flame retardant content in the third column is 47 wt%.

[0067] Example 9

[0068] This embodiment provides a battery that differs from Embodiment 1 in that: the first column comprises EVA and polyphosphazene in a mass ratio of 56:44, the second column comprises EVA and polyphosphazene in a mass ratio of 88:12, and the third column comprises EVA and polyphosphazene in a mass ratio of 56:44. The flame retardant content in the first column is 44 wt%, the flame retardant content in the second column is 12 wt%, and the flame retardant content in the third column is 44 wt%.

[0069] Example 10

[0070] This embodiment provides a battery that differs from Embodiment 1 in that: the first column comprises EVA and polyphosphazene in a mass ratio of 53:47, the second column comprises EVA and polyphosphazene in a mass ratio of 90:10, and the third column comprises EVA and polyphosphazene in a mass ratio of 53:47. The flame retardant content in the first column is 47 wt%, the flame retardant content in the second column is 10 wt%, and the flame retardant content in the third column is 43 wt%.

[0071] Example 11

[0072] This embodiment provides a battery that differs from Embodiment 1 in that: the first column comprises EVA and polyphosphazene in a mass ratio of 58:42, the second column comprises EVA and polyphosphazene in a mass ratio of 87:13, and the third column comprises EVA and polyphosphazene in a mass ratio of 55:45. The flame retardant content in the first column is 42 wt%, the flame retardant content in the second column is 13 wt%, and the flame retardant content in the third column is 45 wt%.

[0073] Example 12

[0074] This embodiment provides a battery that differs from Embodiment 1 in that the polymer hot-melt material in the first column segment of this embodiment is PCL, which replaces EVA by an equal mass. The bonding strength between the core and the column is 23 N / cm.

[0075] Example 13

[0076] This embodiment provides a battery, which differs from Embodiment 12 in that: the polymer hot-melt material in the third column section of this embodiment is PCL, and it replaces EVA by an equal mass. The bonding strength between the core and the column is 12 N / cm.

[0077] Example 14

[0078] This embodiment provides a battery that differs from Embodiment 1 in that the polymer hot-melt material in the second column section of this embodiment is PEO, which replaces EVA by an equal mass. The bonding strength between the core and the columnar body is 24 N / cm.

[0079] Example 15

[0080] This embodiment provides a battery, which differs from Embodiment 1 in that: in this embodiment, the polymer hot-melt material in the first column segment is PCL, which replaces EVA by an equal mass; the polymer hot-melt material in the second column segment is PEO, which replaces EVA by an equal mass. The bonding strength between the core and the columnar body is 18 N / cm.

[0081] Example 16

[0082] This embodiment provides a battery that differs from Embodiment 1 in that the flame retardant in the first column section of this embodiment is calcium phosphate, which replaces polyphosphononitrile by an equal mass.

[0083] Example 17

[0084] This embodiment provides a battery that differs from Embodiment 16 in that the flame retardant in the third column is calcium phosphate, which replaces polyphosphononitrile by an equal mass.

[0085] Example 18

[0086] This embodiment provides a battery that differs from Embodiment 1 in that the flame retardant in the second column section of this embodiment is zinc phosphate, which replaces polyphosphononitrile by an equal mass.

[0087] Example 19

[0088] This embodiment provides a battery that differs from Embodiment 1 in that: in this embodiment, the flame retardant in the first column is calcium phosphate, which replaces polyphosphonic acrylonitrile by an equal mass; in this embodiment, the flame retardant in the second column is zinc phosphate, which replaces polyphosphonic acrylonitrile by an equal mass; and in the third column, the flame retardant is ammonium polyphosphate, which replaces polyphosphonic acrylonitrile by an equal mass.

[0089] Example 20

[0090] This embodiment provides a battery, which differs from Embodiment 1 in that the particle size of the polyphosphononil particles in this embodiment is 5 μm for Dv10, 10 μm for Dv50, and 55 μm for Dv99.

[0091] Example 21

[0092] This embodiment provides a battery, which differs from Embodiment 1 in that the particle size of the polyphosphononil particles in this embodiment is 7 μm for Dv10, 30 μm for Dv50, and 70 μm for Dv99.

[0093] Example 22

[0094] This embodiment provides a battery, which differs from Embodiment 1 in that the particle size of the polyphosphononil particles in this embodiment is 10 μm for Dv10, 50 μm for Dv50, and 50 μm for Dv99.

[0095] The parameters in each embodiment are shown in Table 1-2.

[0096] Table 1 Parameters of each embodiment

[0097]

[0098]

[0099] Table 2 Parameters of each embodiment

[0100]

[0101] Comparative Example 1

[0102] This comparative example provides a battery that differs from Example 1 in that it does not contain columnar parts.

[0103] Comparative Example 2

[0104] This comparative example provides a battery that differs from Example 1 in that the second column is the same as the first column, and the flame retardant content in the columnar body of this comparative example is uniform from the center to both ends.

[0105] Test case

[0106] This test case provides performance tests for various embodiments and comparative battery examples, as detailed below:

[0107] The test method for flame retardant performance is as follows: A fully charged battery is heated from 25°C to 180°C at a rate of 5°C / min, held for 30 minutes, and the battery's state is recorded. "Good" means the battery does not catch fire and the explosion-proof valve is not open; "Bad" means the battery does not catch fire but the explosion-proof valve is open; "Poor" means the battery catches fire.

[0108] Needle penetration test method: Use a steel needle with a diameter of 3mm to penetrate the center of the large surface of the fully charged battery at a 45° angle and a speed of 25mm / s. Observe for 1 hour. If the battery does not catch fire or explode, it passes the needle penetration test. If the battery catches fire or explodes, it fails the needle penetration test.

[0109] Mass energy density: At 25℃, charge and discharge the battery once at a rate of 0.33C (2.0-3.65V), record the discharge energy, and divide the discharge energy by the battery mass to obtain the battery's mass energy density.

[0110] Capacity retention rate after 500 cycles: At 25℃, the battery is cycled with a 1C current (2.0-3.65V). The discharge capacity of the 1st and 500th cycles is recorded, and the ratio of the discharge capacity of the 500th cycle to the discharge capacity of the 1st cycle is calculated. This is the capacity retention rate after 500 cycles.

[0111] Table 3 Performance test results for each embodiment and comparative example

[0112]

[0113]

[0114] As can be seen from the above data, setting a column containing flame retardant in the center of the battery core, with the flame retardant content in the center of the column being lower than that at the ends, can balance the internal temperature of the core, which is beneficial to achieving a flame retardant effect on the battery. At the same time, the presence of the column can increase the winding force of the core, which is beneficial to stabilizing the core structure, improving the battery cycle performance, and also enabling the battery to maintain a high energy density.

[0115] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A battery, characterized by, The battery comprises a shell, a roll core arranged in the shell, the roll core is centrally provided with a columnar body, the columnar body contains a flame retardant, along the length direction of the columnar body, the columnar body has a first column segment, a third column segment and a second column segment arranged between the first column segment and the third column segment, the first column segment, the second column segment and the third column segment contain the flame retardant; The content of the flame retardant in the second column segment is less than the content of the flame retardant in the first column segment and the third column segment, based on the total mass of the flame retardant in the columnar body; the length ratio of the first column segment, the second column segment and the third column segment is 1:1:

1.

2. The battery of claim 1, wherein, The content of the flame retardant in the first column segment is 35-50wt%, the content of the flame retardant in the second column segment is 5-20wt%, and the content of the flame retardant in the third column segment is 35-50wt%, based on 100% of the total mass of the flame retardant in the columnar body.

3. The battery of claim 1, wherein, The particle size Dv10 of the flame retardant particles is 5-10μm, the particle size Dv50 is 10-50μm, and the particle size Dv99 is 50-90μm; and / or, The flame retardant comprises at least one of polyphosphazene, ammonium polyphosphate, phosphate, red phosphorus and organic phosphorus.

4. The battery of claim 1, wherein, The length ratio of the columnar body to the roll core is (91-98):

100.

5. The battery of claim 1, wherein, The columnar body further comprises a high molecular hot melt material, and the first column segment, the second column segment and the third column segment contain the high molecular hot melt material.

6. The battery of claim 5, wherein, The high molecular hot melt material comprises at least one of EVA (ethylene-vinyl acetate copolymer), POE (ethylene-butene polymer), PEO (polyethylene oxide) and PCL (polycaprolactone).

7. The battery of claim 6, wherein, The shell is cylindrical; and / or, the columnar body is cylindrical.

8. The battery according to any one of claims 1 to 7, characterized in that, The bonding strength between the interior of the roll core and the columnar body is 12-30N / cm.

9. An electrical device comprising the battery of any one of claims 1-8.

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