Cylindrical battery

Abstract

The utility model relates to battery technical field discloses a cylindrical battery, include: including: shell, cover plate subassembly, bottom plate and electric core, the shell is in the both ends of first direction through and forms upper port and lower port respectively, the electric core is located in the shell, the cover plate subassembly covers the upper port, the cover plate subassembly includes the anti -explosion sheet, be equipped with the fracture on the anti -explosion sheet, the wall thickness of fracture is less than the wall thickness of other parts of anti -explosion sheet, the bottom plate cover is equipped with the lower port, be equipped with weak part on the bottom plate, the wall thickness of weak part is less than the wall thickness of other parts of bottom plate all. The utility model adopts double -layer anti -explosion valve design, when the electric core short circuit leads to the rupture of upper anti -explosion valve, if gas and heat do not have time to discharge, the lower anti -explosion valve will break down with it and realize the rapid pressure relief, effectively avoid the explosion to occur.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a cylindrical battery. Background Technology

[0002] Cylindrical batteries are widely used in modern electronic products, especially in portable devices and power tools. Conventional cylindrical batteries typically employ an integrated explosion-proof structure with a cap assembly consisting of a top cover, an explosion-proof diaphragm, and an insulating ring. When the internal pressure of the battery increases, the explosion-proof diaphragm flips and disengages from the connecting piece to cut off power; if the pressure continues to increase, the diaphragm ruptures to release pressure. However, this design has significant drawbacks in practical applications: when a short circuit occurs, the explosion-proof diaphragm, due to deformation resistance or material strength redundancy, is prone to delayed flipping response or even failure, preventing the timely release of high-temperature gases and potentially leading to thermal runaway and explosion; after the explosion-proof diaphragm flips open, insufficient venting efficiency can cause electrolyte splashing, resulting in injury to users. Therefore, a more reliable explosion-proof design is urgently needed to improve battery safety and reduce the probability of accidents. Utility Model Content

[0003] The purpose of this invention is to design a cylindrical battery with good safety performance.

[0004] To achieve the above objectives, this utility model provides a cylindrical battery, comprising: a casing, a cover plate assembly, a base plate, and a battery cell; the casing has two through-holes in a first direction, forming an upper port and a lower port respectively, the battery cell is disposed inside the casing, the cover plate assembly is disposed on the upper port, the cover plate assembly includes an explosion-proof sheet, the explosion-proof sheet has a fracture portion, the wall thickness of the fracture portion is less than the wall thickness of other parts of the explosion-proof sheet; the base plate is disposed on the lower port, the base plate has a weak portion, the wall thickness of the weak portion is less than the wall thickness of other parts of the base plate.

[0005] Furthermore, the cover plate assembly also includes a top cover, an insulating ring, and a connecting piece; the connecting piece, the explosion-proof piece, and the top cover are arranged sequentially along the first direction; the connecting piece is connected to the battery cell; the explosion-proof piece has an upper edge and a lower edge; the lower edge is insulated from the connecting piece by the insulating ring; the upper edge is electrically connected to the top cover; the center of the explosion-proof piece protrudes towards the connecting piece and is electrically connected to the center of the connecting piece; the fracture portion is located between the center of the explosion-proof piece and the lower edge.

[0006] Furthermore, the explosion-proof sheet is provided with at least two fracture portions; the at least two fracture portions are symmetrically arranged relative to the center of the explosion-proof sheet.

[0007] Furthermore, the explosion-proof sheet is provided with at least four fracture portions; the at least four fracture portions are arranged sequentially along the radial direction of the explosion-proof sheet.

[0008] Furthermore, the explosion-proof sheet has a blind hole on the side facing the upper port, and the blind hole defines the fracture portion.

[0009] Furthermore, it also includes a gasket, which is disposed between the lower port and the base plate, and the gasket has multiple through holes.

[0010] Furthermore, it also includes a protective sheet, which covers the weak portion on the side opposite to the lower port along the first direction.

[0011] Furthermore, a first groove is provided on the side of the base plate facing the lower port, and the first groove defines the weak part.

[0012] Furthermore, a connecting hole is provided on the base plate, and a thin sheet is provided in the connecting hole to define the weak part. The thin sheet and the base plate are integral parts.

[0013] Furthermore, the structural strength and stiffness of the weak part are both greater than those of the fractured part.

[0014] Compared with the prior art, the cylindrical battery of this utility model has the following advantages:

[0015] This embodiment of the cylindrical battery achieves a dual safety protection mechanism by incorporating a fracture section on the explosion-proof sheet and a weak section on the base plate. When the internal pressure of the battery abnormally increases, it can effectively release pressure, preventing the battery from exploding and significantly improving battery safety. The fracture section of the explosion-proof sheet releases pressure first, handling minor pressure anomalies, while the weak section of the base plate only ruptures when the pressure further increases, handling more severe pressure anomalies. This staged pressure release improves the reliability of safety protection. The structure is simple in design, easy to manufacture and assemble, and has low cost, making it suitable for large-scale production and application. Attached Figure Description

[0016] Figure 1 This is an internal cross-sectional view of a cylindrical battery according to an embodiment of the present invention;

[0017] Figure 2 This is a partially enlarged cross-sectional view of a cylindrical battery according to an embodiment of the present invention;

[0018] Figure 3 This is a cross-sectional view of the bottom plate of the cylindrical battery according to an embodiment of the present invention;

[0019] Figure 4This is a cross-sectional view of the bottom plate of a cylindrical battery according to another embodiment of the present invention.

[0020] In the figure, 1 is the outer casing; 11 is the upper port; 12 is the lower port; 2 is the cover assembly; 21 is the explosion-proof sheet; 211 is the fracture part; 212 is the upper edge; 213 is the lower edge; 214 is the blind hole; 22 is the top cover; 23 is the insulating ring; 24 is the connecting piece; 3 is the bottom plate; 31 is the weak part; 32 is the first groove; 33 is the connecting hole; 34 is the thin sheet; 4 is the battery cell; 5 is the gasket; 51 is the through hole; x is the first direction. Detailed Implementation

[0021] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0022] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" used to indicate the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model 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 utility model.

[0023] In the description of this utility model, it should be understood that the terms "connected," "linked," and "fixed," etc., used in this utility model 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 a welded 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 explicitly defined. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0024] In this invention, terms such as "first" and "second" are used to describe various types of information, but this information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this invention, "first" information can also be referred to as "second" information, and similarly, "second" information can also be referred to as "first" information.

[0025] Reference Figure 1 and Figure 2A cylindrical battery according to an embodiment of the present invention includes: a shell 1, a cover plate assembly 2, a base plate 3, and a battery cell 4; the shell 1 is through at both ends in a first direction x and forms an upper port 11 and a lower port 12 respectively; the battery cell 4 is disposed inside the shell 1; the cover plate assembly 2 is disposed on the upper port 11; the cover plate assembly 2 includes an explosion-proof sheet 21; the explosion-proof sheet 21 has a fracture portion 211; the wall thickness of the fracture portion 211 is less than the wall thickness of other parts of the explosion-proof sheet 21; the base plate 3 is disposed on the lower port 12; the base plate 3 has a weak portion 31; the wall thickness of the weak portion 31 is less than the wall thickness of other parts of the base plate 3.

[0026] Under normal operating conditions, cell 4 charges and discharges. When the battery experiences abnormal conditions such as overcharging or overheating, causing the internal pressure of the battery to rise: the fractured part 211 on the explosion-proof sheet 21, due to its thin wall thickness, will preferentially deform or break, thereby releasing some of the internal pressure of the battery and preventing the pressure from rising further; if the pressure relief of the explosion-proof sheet 21 is insufficient to control the pressure, as the internal pressure continues to rise, the weakest part 31 on the base plate 3, due to its thinnest wall thickness, will rupture, thereby further releasing the internal pressure and gas of the battery and preventing the battery from exploding.

[0027] By incorporating a fracture section 211 on the explosion-proof sheet 21 and a weak section 31 on the base plate 3, a dual safety protection mechanism is achieved. When the internal pressure of the battery abnormally increases, the pressure can be effectively released to prevent the battery from exploding, significantly improving battery safety.

[0028] The fractured portion 211 of the explosion-proof disc 21 first releases pressure, which can cope with minor pressure anomalies. The weak portion 31 of the base plate 3 only ruptures when the pressure increases further, which can cope with more severe pressure anomalies, thus achieving graded pressure relief and improving the reliability of safety protection. This structure is simple in design, easy to manufacture and assemble, and has low cost, which is conducive to large-scale production and application.

[0029] In some embodiments of this application, the cover plate assembly 2 further includes a top cover 22, an insulating ring 23, and a connecting piece 24; the connecting piece 24, the explosion-proof piece 21, and the top cover 22 are arranged sequentially along the first direction x; the connecting piece 24 is connected to the battery cell 4; the explosion-proof piece 21 has an upper edge 212 and a lower edge 213; the lower edge 213 is insulated from the connecting piece 24 by the insulating ring 23; the upper edge 212 is electrically connected to the top cover 22; the center of the explosion-proof piece 21 protrudes towards the connecting piece 24 and is electrically connected to the center of the connecting piece 24; the fracture portion 211 is located between the center of the explosion-proof piece 21 and the lower edge 213.

[0030] Specifically, the connecting piece 24 can be formed by stamping, and its lower surface is electrically connected to the electrode tab of the battery cell 4; the explosion-proof piece 21 has a dome structure with the center convex downwards, and its lower surface, i.e., the lower edge 213, is insulated from the edge of the connecting piece 24 by an annular insulating ring 23; the explosion-proof piece 21 abuts against the center of the connecting piece 24 through its downwardly convex center, forming a stable electrical connection path. The top cover 22 can convex upwards to form a support and also serves as a positive electrode. A through groove is provided on the top cover 22 to facilitate gas discharge when the explosion-proof piece 21 breaks. The upper surface of the edge of the explosion-proof piece 21, i.e., the upper edge 212, makes surface contact with the edge of the top cover 22 by abutting, so that the top cover 22 and the explosion-proof piece 21 form a conductive path. The fracture part 211 is located in the annular area between the center of the explosion-proof piece 21 and the lower edge 213.

[0031] In some embodiments of this application, the explosion-proof sheet 21 is provided with at least two fracture portions 211; the at least two fracture portions 211 are symmetrically arranged relative to the center of the explosion-proof sheet 21. In a specific embodiment, there are two fracture portions 211, which are equidistantly distributed in an annular region between the center of the explosion-proof sheet 21 and the lower edge 213, dividing the annular region into two semicircles.

[0032] Under normal operating conditions, the current from the positive terminal of cell 4 flows to the external circuit through connecting piece 24, explosion-proof piece 21, and top cover 22. When the internal pressure of the battery rises abnormally, such as due to overcharging, over-discharging, or short circuit causing thermal runaway of cell 4, the gas pressure generated inside the battery will first act on the explosion-proof piece 21. The explosion-proof piece 21 will first flip, with its center changing from a downward convex shape to an upward convex shape, thereby detaching from the connecting piece 24 and cutting off power. If the internal pressure increases further, due to the thin wall thickness of the fracture part 211, when the pressure reaches a preset threshold, both fracture parts 211 will rupture simultaneously, allowing the explosion-proof piece 21 to release gas from the middle, thereby releasing the internal pressure of the battery and preventing the battery from exploding due to the continuous increase in pressure.

[0033] Because the two fracture sections 211 are symmetrically arranged relative to the center of the explosion-proof disc 21, the pressure can be applied evenly to the explosion-proof disc 21, avoiding deformation or failure of the explosion-proof disc 21 caused by single-point stress. At the same time, the symmetrical fracture section 211 design can better control the direction of pressure release.

[0034] In some embodiments of this application, the explosion-proof sheet 21 is provided with at least four fracture portions 211; the at least four fracture portions 211 are arranged sequentially along the radial direction of the explosion-proof sheet 21. In a specific embodiment of this application, the explosion-proof sheet 21 is provided with four fracture portions 211, wherein two fracture portions 211 form a group, and the two groups of fracture portions 211 are symmetrically arranged relative to the center of the explosion-proof sheet 21. The two fracture portions 211 in the same group are located on the same radius of the explosion-proof sheet 21, and the distance from the center of the explosion-proof sheet 21 increases sequentially, that is, the four fracture portions 211 are located on the same diameter of the explosion-proof sheet 21. When the internal pressure of the battery exceeds the limit, the innermost fracture portion 211 breaks first to form a small area pressure relief port (releasing the initial pressure peak); as the pressure continues to rise, the outer fracture portions 211 break sequentially, and the pressure relief area gradually expands, realizing the pressure gradient release. Compared with the single fracture portion 211 structure, this design can avoid the risk of sudden pressure drop caused by instantaneous complete rupture.

[0035] In some embodiments of this application, the explosion-proof sheet 21 has a blind hole 214 on the side facing the upper port 11, and the blind hole 214 defines the fracture portion 211. Under normal operating conditions, the blind hole 214 does not affect the strength and structure of the explosion-proof sheet 21, ensuring that the explosion-proof sheet 21 can work stably for a long time under normal conditions. The circular blind hole 214 also prevents the internal battery cell 4 from being exposed in a large area after the explosion-proof sheet 21 is flipped over, as this would easily cause the electrolyte to splash outwards. In other embodiments of this application, the fracture portion 211 can also be designed as a V-shaped groove, a cross-shaped groove, or other structures.

[0036] In some embodiments of this application, a gasket 5 is also included, which is disposed between the lower port 12 and the base plate 3, and the gasket 5 has a plurality of through holes 51. The gasket 5 can provide a certain degree of support and cushioning, absorb external impacts, and protect the base plate 3 from damage.

[0037] In some embodiments of this application, a protective sheet is also included, which covers the weak portion 31 on the side opposite to the lower port 12 along the first direction x. In this embodiment, the protective sheet can be a transparent or translucent plastic sheet made of a wear-resistant and corrosion-resistant material. The size of the protective sheet is matched to the weak portion 31, and its shape is adapted to the contour of the weak portion 31, so as to better cover and protect the weak portion 31. The protective sheet is installed on the outside of the weak portion 31 by a suitable bonding technique (e.g., double-sided tape, hot pressing, or glue), and is placed on the side of the weak portion 31 opposite to the lower port 12 along the first direction x, ensuring that during use, the weak portion 31 is not only effectively prevented from being subjected to external mechanical impact, but also prevented from being deformed or broken due to external forces.

[0038] When the internal pressure of the battery rises abnormally and the weak part 31 ruptures, the protective sheet can guide the pressure to be released in a preset direction, preventing fragments of the base plate 3 from flying and improving the safety of the battery.

[0039] Reference Figure 3 In some embodiments of this application, a first groove 32 is provided on the side of the base plate 3 facing the lower port 12, and the first groove 32 defines the weak part 31. The first groove 32 can be formed by stamping, etching or other processing methods, and it can be located at the center of the base plate 3 or near the edge of the base plate 3 to facilitate impact breaking.

[0040] Reference Figure 4 In some embodiments of this application, the base plate 3 has a connecting hole 33, and a thin sheet 34 is provided in the connecting hole 33 to define the weak part 31. The thin sheet 34 and the base plate 3 are integral. The thin sheet 34 can be formed by etching at the same position on both sides of the base plate 3 in the first direction x, so as to ensure a tight bond between the thin sheet 34 and the base plate 3, and to ensure the strength and reliability of the weak part 31.

[0041] In some embodiments of this application, the structural strength and stiffness of the weak portion 31 are greater than those of the fracture portion 211. A double-layer explosion-proof valve design is used, with explosion-proof valves at both the top and bottom. The upper explosion-proof valve is the fracture portion 211 formed by a circular hole in the explosion-proof plate 21, positioned between the center edge of the explosion-proof plate 21 for easy impact breaking. The lower explosion-proof valve is the weak portion 31 formed by a circular hole in the base plate 3. A gasket 5 is provided above the base plate 3, with a hollow area of ​​the same size cut out on the gasket 5 directly above the weak portion 31 for convenience. A transparent rigid plastic sheet is attached to the outside of the base plate 3 directly opposite the weak portion 31 as a protective layer. The top explosion-proof valve plays a primary role, while the bottom explosion-proof valve plays an auxiliary role. The pressure at which the fractured part 211 bursts is 0.2 ± 0.05 MPa greater than the pressure at which the connecting piece 24 and the explosion-proof piece 21 separate, while the pressure at which the weak part 31 bursts is 0.5 to 0.7 MPa greater than the pressure at which the fractured part 211 bursts.

[0042] When the explosion-proof plate 21 of the cover assembly 2 is flipped over, as the internal pressure of the battery increases, its fracture part 211 is broken open and the air pressure is released. The explosion-proof valve of the weak part 31 of the base plate 3 is designed to prevent the safety hazard of explosion caused by excessive internal pressure that cannot be released in time. At the same time, the weak part 31 can be designed as a small circular hole to prevent the electrolyte inside from splashing outwards after the weak part 31 is broken open by the internal air pressure of the battery.

[0043] In summary, this utility model embodiment provides a cylindrical battery with a double-layer explosion-proof valve structure. The upper explosion-proof valve is on the cover plate assembly 2, and the lower explosion-proof valve is at the bottom plate 3. The pressure at which the connecting piece 24 and the explosion-proof piece 21 disconnect, the disconnection pressure of the upper explosion-proof valve (i.e., the fracture part 211), and the rupture pressure of the lower explosion-proof valve (i.e., the weak part 31) increase sequentially. The disconnection pressure of the upper explosion-proof valve is slightly greater than the pressure at which the connecting piece 24 and the explosion-proof piece 21 separate. When the internal pressure of the battery causes the explosion-proof piece 21 to flip, resulting in the separation of the connecting piece 24 and the explosion-proof piece 21, At this point, the battery is internally open. If the temperature and internal pressure continue to increase, the upper explosion-proof valve will open first, allowing heat and gas to escape from the explosion-proof plate 21 through the fracture part 211, reducing the risk of battery explosion. However, if the upper explosion-proof valve's exhaust volume is insufficient and the internal pressure continues to increase, the explosion-proof valve on the bottom plate 3 will open. The top and bottom explosion-proof valves will work together to exhaust the gas, allowing the heat and gas generated by the battery in a short time to be discharged as quickly as possible, avoiding explosion and ensuring battery safety.

[0044] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A cylindrical battery, characterized in that, include: Casing, cover assembly, base plate and battery cell; The outer casing extends through both ends in a first direction, forming an upper port and a lower port respectively. The battery cell is disposed inside the outer casing. The cover plate assembly covers the upper port. The cover plate assembly includes an explosion-proof sheet with a fracture portion. The wall thickness of the fracture portion is less than the wall thickness of other parts of the explosion-proof sheet. The bottom plate covers the lower port and has a weak portion. The wall thickness of the weak portion is less than the wall thickness of other parts of the bottom plate.

2. The cylindrical battery as described in claim 1, characterized in that, The cover plate assembly further includes a top cover, an insulating ring, and a connecting piece; the connecting piece, the explosion-proof piece, and the top cover are arranged sequentially along the first direction; the connecting piece is connected to the battery cell; the explosion-proof piece has an upper edge and a lower edge; the lower edge is insulated from the connecting piece by the insulating ring; the upper edge is electrically connected to the top cover; the center of the explosion-proof piece protrudes towards the connecting piece and is electrically connected to the center of the connecting piece; the fracture portion is located between the center of the explosion-proof piece and the lower edge.

3. The cylindrical battery as described in claim 2, characterized in that, The explosion-proof sheet is provided with at least two fracture portions; the at least two fracture portions are symmetrically arranged with respect to the center of the explosion-proof sheet.

4. The cylindrical battery as described in claim 2, characterized in that, The explosion-proof sheet is provided with at least four fracture portions; the at least four fracture portions are arranged sequentially along the radial direction of the explosion-proof sheet.

5. The cylindrical battery as described in claim 1, characterized in that, The explosion-proof sheet has a blind hole on the side facing the upper port, and the blind hole defines the fracture portion.

6. The cylindrical battery as described in claim 1, characterized in that, It also includes a gasket, which is disposed between the lower port and the base plate, and the gasket has multiple through holes.

7. The cylindrical battery as described in claim 1, characterized in that, It also includes a protective sheet, which is disposed on the side of the weak portion away from the lower port along the first direction.

8. The cylindrical battery as described in claim 1, characterized in that, A first groove is provided on the side of the base plate facing the lower port, and the first groove defines the weak part.

9. The cylindrical battery as described in claim 1, characterized in that, The base plate has a connecting hole, and a thin sheet is provided in the connecting hole to define the weak part. The thin sheet and the base plate are integral parts.

10. The cylindrical battery as described in claim 1, characterized in that, The structural strength and stiffness of the weak part are both greater than those of the fractured part.

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