A cylindrical sodium-ion battery with high reliability

Abstract

The utility model discloses a cylindrical sodium ion battery with high reliability, which comprises a cylindrical metal shell and a bare cell. The bare cell is encapsulated inside the cylindrical metal shell. The bare cell comprises a negative electrode sheet and a positive electrode sheet. The negative electrode sheet and the positive electrode sheet are wound into a shape through a diaphragm. The negative electrode sheet wraps the positive electrode sheet and forms a negative electrode current collector exposed area at the outermost periphery of the bare cell. The ratio of the diameter of the bare cell to the inner diameter of the cylindrical metal shell is 0.985-0.995. After the bare cell is injected with liquid and expands, the negative electrode sheet and the inner wall of the cylindrical metal shell are electrically connected through the contact between the negative electrode current collector exposed area and the inner wall of the cylindrical metal shell. The cylindrical sodium ion battery with high reliability has the characteristics of high reliability, low safety risk and excellent rate performance.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of sodium ion battery, specifically point to a kind of cylindrical sodium ion battery with high reliability. BACKGROUND

[0002] Cylindrical sodium ion battery is an emerging battery technology, mainly used in energy storage and electric vehicles and other fields. Compared with traditional lithium-ion batteries, sodium-ion batteries have some unique advantages and challenges.

[0003] The working principle of cylindrical sodium ion battery is similar to that of lithium-ion battery, both of which store and release electrical energy by moving ions in the electrolyte between the positive and negative electrodes. During charging, sodium ions are released from the positive electrode material, migrate through the electrolyte to the negative electrode, and are embedded on the negative electrode; during discharging, sodium ions are released from the negative electrode and return to the positive electrode.

[0004] In terms of specific structure, cylindrical sodium ion battery usually adopts standard cylindrical shell (such as 18650 or 21700 model), which makes the battery have good compatibility and scalability in production and application.

[0005] In terms of specific process, cylindrical battery mainly adopts steel shell rolling groove sealing process, and in the assembly process, resistance welding or laser penetration welding process is needed to weld the negative electrode tab to the bottom of the steel shell.

[0006] However, the welding process has the following risks: such as incomplete welding, leading to contact failure and potential overheating risk; such as overwelding, leading to short circuit risk; such as the existence of welding beads, leading to short circuit risk. The above abnormalities may cause fire safety risk of the battery during use. INVENTION CONTENTS

[0007] The utility model aims to provide a cylindrical sodium ion battery with high reliability, which has the characteristics of high reliability, low safety risk and excellent rate performance.

[0008] The utility model can be realized through the following technical solutions:

[0009] The utility model discloses a cylindrical sodium ion battery with high reliability, which comprises a cylindrical metal shell and a bare cell, the bare cell is packaged inside the cylindrical metal shell, the bare cell comprises a negative plate and a positive plate, the negative plate and the positive plate are wound into a shape through a diaphragm, the negative plate wraps the positive plate and forms a negative current collector exposed area at the outermost periphery of the bare cell, the ratio of the diameter of the bare cell to the inner diameter of the cylindrical metal shell is 0.985-0.995, and the negative plate and the inner wall of the cylindrical metal shell are in electrical conduction through the contact between the negative current collector exposed area and the inner wall of the cylindrical metal shell after the liquid injection and expansion of the bare cell.

[0010] Further, the negative current collector exposed area at the outermost periphery of the bare cell is fixed and formed into a roll core by a termination tape, which facilitates subsequent bare cell housing operation.

[0011] Further, the bare cell further comprises a positive tab, the positive tab is arranged at the top center of the bare cell, and the positive tab realizes electrical connection between the positive plate and the cap at the top of the cylindrical metal shell, which is consistent with the existing process and facilitates processing.

[0012] Further, the bare cell further comprises a negative tab, the negative tab is welded to the negative current collector exposed area and is in electrical conduction with the bottom or inner wall of the cylindrical metal shell, which can be flexibly arranged as needed to ensure battery performance.

[0013] Further, the cylindrical metal shell is a cylindrical steel shell or a cylindrical aluminum shell, which can be flexibly selected.

[0014] Further, the negative plate current collector is a copper foil or an aluminum foil, both of which have excellent electrical conduction effect.

[0015] Further, the positive plate is a polyanion material positive plate, a layered oxide material positive plate or a Prussian blue material positive plate, which meets the use needs of different types of batteries.

[0016] Further, the negative plate is a soft carbon negative plate or a hard carbon negative plate, and the negative plate is provided with a soft carbon active material layer or a hard carbon active material layer, which can be flexibly selected in combination with performance.

[0017] Further, the negative tab is an aluminum foil tab or a copper foil tab, which has excellent weldability and conductivity.

[0018] Further, the bare cell is fixed and closed inside the cylindrical metal shell by a cap after being sealed by a roll groove and a buckling edge.

[0019] The utility model discloses a cylindrical sodium ion battery with high reliability has the following beneficial effects:

[0020] First, the reliability is high, the utility model makes full use of the volume expansion effect of the electrode sheet of bare electric core in the charge and discharge process, adopts the negative electrode current collector exposed area of the outermost circle of roll core without covering negative active material and the close contact of cylindrical shell inner wall forms the conductive network, does not need to carry out the welding and can realize the electric conduction of negative electrode sheet and cylindrical shell, improves the reliability.

[0021] Second, the safety risk is low, the electric conduction mode of the negative electrode sheet and the cylindrical shell of the utility model does not need additional pad welding, avoids the failure risk of high energy output and the short circuit risk of the welding bead falling in the cylindrical shell, reduces the safety risk of battery.

[0022] Third, the rate performance is excellent, by forming the negative electrode current collector exposed area of the outermost circle of bare electric core, the exposed area and the inner wall of cylindrical shell form a large volume of electric conduction area, meet the large current charge and discharge demand, improve the rate performance of battery. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is the exploded structural schematic diagram of the utility model of a cylindrical sodium ion battery with high reliability;

[0024] Figures 2-3 It is the bare electric core structure schematic diagram of the utility model of a cylindrical sodium ion battery with high reliability;

[0025] Figure 4 It is the rate curve and capacity retention rate of 18650 electric core of traditional process structure;

[0026] Figure 5 It is the rate curve and capacity retention rate of 18650 electric core of the structure production of the utility model.

[0027] The marks in the drawing include: 100, bare electric core;110, positive electrode lug;120, negative electrode sheet;130, termination adhesive tape;140, negative electrode lug;200, cylindrical metal shell. DETAILED DESCRIPTION

[0028] In order to make the personnel in the technical field better understand the technical scheme of the utility model, the utility model product is further explained in detail below in combination with examples.

[0029] As Figures 1-3The utility model discloses a high reliability cylindrical sodium ion battery, including cylindrical metal shell 200 and bare electric core 100, bare electric core 100 is encapsulated in the inside of cylindrical metal shell 200, bare electric core 100 includes negative plate 120 and positive plate (not shown in the drawing), and negative plate 120 is formed by the winding of the diaphragm insulation with positive plate, and negative plate 120 is wrapped positive plate and forms negative current collector exposed area in the outermost of bare electric core 100, and the ratio of the diameter a of bare electric core 100 and the inner diameter b of cylindrical metal shell 200 is 0.985-0.995, and after bare electric core 100 is injected liquid and expands, realizes the electric conduction of negative plate 120 and the inner wall of cylindrical metal shell 200 through negative current collector exposed area and the inner wall of cylindrical metal shell 200.

[0030] As Figures 1-3 Shown, to avoid bare electric core loose after winding forming, and the negative current collector exposed area of bare electric core 100 outermost is fixed by the termination adhesive tape 130 and is formed into the core.

[0031] As Figures 1-3 Shown, bare electric core still includes positive tab 110, and positive tab 110 is arranged at the top center of bare electric core 100, and the positive tab 110 realizes the electric connection of positive plate and the cap (not shown in the drawing) of cylindrical metal shell 100 top. The connecting mode of the cap and positive plate through positive tab is the mode of the prior art.

[0032] As Figure 3 Shown, bare electric core 100 still includes negative tab 140, and negative tab 140 is welded in negative current collector exposed area and contacts the bottom or inner wall of cylindrical metal shell 200 and is electrically conducted. Here, setting negative tab is mainly based on the bare electric core with larger diameter, such as the diameter of bare electric core is greater than 21mm, to effectively improve the charge-discharge rate, can be attached to the negative tab, but the negative tab is not necessary, is set according to the performance requirement, and is not the denial of the technical effect of the foregoing negative welding-free mode, but the additional improvement of performance.

[0033] In the utility model, for the material selection of shell current collector, all use existing materials, such as cylindrical metal shell is cylindrical steel shell or cylindrical aluminum shell, and negative plate current collector is copper foil or aluminum foil, and correspondingly, negative tab is aluminum foil tab or copper foil tab.

[0034] The sodium ion battery of the utility model satisfies the needs of different types of sodium ion batteries, such as the positive plate is a polyanion type material positive plate, a layered oxide material positive plate or a prussian blue material positive plate, such as the negative plate is a soft carbon negative plate or a hard carbon negative plate, and the negative plate is provided with a soft carbon active material layer or a hard carbon active material layer.

[0035] In the sealing process, the utility model adopts the existing mature process mode, such as the naked electric core is sealed by the rolling groove buckle edge and is fixed and closed in the cylindrical metal shell by the cap.

[0036] In order to verify the effect of the utility model, the rate performance of the electric core is tested to judge, and the specific like Figure 4 And Figure 5 By comparison, the cylindrical battery adopting the structure of the utility model has more excellent rate performance than the traditional structure of the cylindrical battery.

[0037] In the description of the utility model, it should be understood that the terms such as "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model.

[0038] In addition, the terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the utility model, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0039] In the utility model, unless otherwise specifically defined and limited, the terms "installation", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication or interaction relationship between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0040] The above examples are only specific embodiments of the utility model, which are described in detail and in detail, but cannot be understood as a limitation on the scope of the utility model patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the utility model, a number of modifications and improvements can be made, and these obvious alternative forms all belong to the protection scope of the utility model.

Claims

1. A cylindrical sodium-ion battery with high reliability, comprising a cylindrical metal shell and a bare cell, the bare cell is packaged inside the cylindrical metal shell, characterized in that: The bare battery core comprises a negative electrode sheet and a positive electrode sheet, the negative electrode sheet and the positive electrode sheet are wound and formed by a separator, the negative electrode sheet wraps the positive electrode sheet and forms a negative electrode current collector exposed area at the outermost periphery of the bare battery core, the ratio of the diameter of the bare battery core to the inner diameter of the cylindrical metal shell is 0.985-0.995, and after liquid injection and expansion of the bare battery core, the negative electrode sheet is in electrical conduction with the inner wall of the cylindrical metal shell through the negative electrode current collector exposed area and the inner wall of the cylindrical metal shell.

2. The high-reliability cylindrical sodium-ion battery according to claim 1, characterized by: The negative electrode current collector exposed area at the outermost periphery of the bare battery core is fixed and formed by a termination tape. 3.The high-reliability cylindrical sodium-ion battery according to claim 1, characterized in that: The bare battery core further comprises a positive electrode tab, the positive electrode tab is arranged at the center of the top of the bare battery core, and the positive electrode tab is used to realize electrical connection between the positive electrode sheet and the cap at the top of the cylindrical metal shell. 4.The high-reliability cylindrical sodium-ion battery according to claim 3, characterized in that: The bare battery core further comprises a negative electrode tab, the negative electrode tab is welded to the negative electrode current collector exposed area and is in electrical conduction with the bottom or the inner wall of the cylindrical metal shell. 5.The high-reliability cylindrical sodium-ion battery according to claim 4, characterized in that: The cylindrical metal shell is a cylindrical steel shell or a cylindrical aluminum shell. 6.The high-reliability cylindrical sodium-ion battery according to claim 5, characterized in that: The negative electrode sheet current collector is a copper foil or an aluminum foil. 7.The high-reliability cylindrical sodium-ion battery according to claim 6, characterized in that: The positive electrode sheet is a polyanion material positive electrode sheet, a layered oxide material positive electrode sheet or a Prussian blue material positive electrode sheet. 8.The high-reliability cylindrical sodium-ion battery according to claim 7, characterized in that: The negative electrode sheet is a soft carbon negative electrode sheet or a hard carbon negative electrode sheet, and the negative electrode sheet is provided with a soft carbon active material layer or a hard carbon active material layer. 9.The high-reliability cylindrical sodium-ion battery according to claim 8, characterized in that: The negative electrode tab is an aluminum foil tab or a copper foil tab. 10.The high-reliability cylindrical sodium-ion battery according to claim 9, characterized in that: The bare battery core is fixed and sealed in the cylindrical metal shell by a cap after being sealed by a groove rolling and edge buckling.

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