WO2023087556A1 - Cover plate of lithium ion battery, and lithium ion battery comprising cover plate and explosion-proof method therefor - Google Patents

Abstract

The present invention relates to the technical field of lithium ion batteries, and in particular to a cover plate of a lithium ion battery, and a lithium ion battery comprising the cover plate and an explosion-proof method therefor. The cover plate of a lithium ion battery comprises: a rivet, an annular sealing ring, an annular outer ring, an upper sealing layer and a lower sealing layer. The rivet comprises an end cover, a cylindrical boss is formed downwards at a central position of a lower surface of the end cover, and a wedge-shaped raised ring is formed on an outer periphery of the cylindrical boss; an annular positioning ring extends downwards from an inner ring of a lower surface of the annular sealing ring, and a wedge-shaped positioning ring extends downwards from a lower surface of the annular positioning ring; the annular positioning ring and the wedge-shaped positioning ring are both sleeved on the outer periphery of the cylindrical boss of the rivet, and an inclined surface of the wedge-shaped positioning ring is closely fitted to an inclined surface of the wedge-shaped raised ring; and an upper sealing layer is formed between the lower surface of the end cover of the rivet and an upper surface of the annular sealing ring, and a lower sealing layer is formed between the lower surface of the annular sealing ring and the annular outer ring. The present invention is provided with a double-seal structure, increasing the reliability of sealing, has a simple structure, ensuring an effective space of a micro battery, and also has a high safety performance.

Description

Lithium-ion battery cover plate, lithium-ion battery including the cover plate, and explosion-proof method thereof technical field

The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery cover plate, a lithium ion battery containing the cover plate and an explosion-proof method thereof.

Background technique

Lithium-ion battery is a secondary battery (rechargeable battery) that mainly relies on the movement of lithium ions between the positive and negative electrodes to work. During the charging and discharging process, lithium ions intercalate and deintercalate back and forth between the two electrodes: during charging, lithium ions are deintercalated from the positive electrode, inserted into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge.

At present, there are three main packaging structures for micro button-type lithium-ion batteries: the upper and lower case riveting type, the cover plate shell riveting type and the cover plate shell welding type. Among them, the most commonly used method is the welding of the cover plate shell. In this way, the lithium-ion battery cover plate is generally sealed and connected by metal riveting and pressing elastic seals, or sealed and connected by adhesive bonding. In the connection method of metal riveting, the metal needs to ensure the compression of the elastic seal after deformation, so it is necessary to ensure sufficient metal strength, so the thickness of this type of lithium-ion battery cover is thick. In the adhesive connection method, although the thickness of the lithium-ion battery cover plate is thin, the requirements for colloidal strength, adhesive performance, thermal expansion performance, and water vapor barrier performance are very high. At present, there is still no colloidal material suitable for mass production. Meet the above requirements.

Contents of the invention

The technical problem to be solved by the present invention is: in order to solve the problems of thick lithium-ion battery cover plate, poor sealing performance of traditional riveting structure, and high requirements for adhesive connection, a lithium-ion battery cover plate provided by the present invention is provided with a double sealing structure , increasing the reliability of the seal, and the structure is simple, the thickness of the cover plate is thin, and the space occupied is small, ensuring the effective space of the micro battery.

The technical solution adopted by the present invention to solve the technical problem is: a lithium-ion battery cover plate, including: rivets, annular sealing rings, annular outer rings, upper sealing layers and lower sealing layers; the rivets include end caps, the A cylindrical protrusion is formed downward at the center of the lower surface of the end cover, and a wedge-shaped convex ring is formed on the outer periphery of the cylindrical protrusion; an annular positioning ring extends downward from the inner ring of the lower surface of the annular sealing ring, and the annular positioning ring The central axis of the ring is coaxial with the central axis of the annular sealing ring, and a wedge-shaped positioning ring extends downward from the lower surface of the annular positioning ring; the bottom of the wedge-shaped bead is a plane, and the upper surface of the wedge-shaped bead The surface is a bevel, and the width gradually widens from top to bottom, the inner ring of the wedge-shaped positioning ring is a bevel, and the annular positioning ring and the wedge-shaped positioning ring are both sleeved on the outer periphery of the cylindrical protrusion of the rivet, The inner wall of the annular positioning ring is in close contact with the outer wall of the cylindrical protrusion, the inclined surface of the wedge-shaped positioning ring matches the inclined surface of the wedge-shaped bead, and the inclined surface of the wedge-shaped positioning ring is matched with the inclined surface of the wedge-shaped bead. The inclined surface of the rivet end cap is tightly fitted; the lower surface of the end cap is bonded to the upper surface of the annular sealing ring, and the upper seal is formed between the lower surface of the rivet end cap and the upper surface of the annular sealing ring. layer; the inner wall of the annular outer ring body is sleeved on the outer wall of the annular positioning ring, the inner wall of the annular outer ring body is closely attached to the outer wall of the annular positioning ring, and the lower surface of the annular sealing ring is in contact with the outer wall of the annular positioning ring The annular outer rings are bonded and fixed, and the lower sealing layer is formed between the lower surface of the annular sealing ring and the annular outer rings. The lithium-ion battery cover plate of the present invention is specially provided with a double sealing structure, which increases the reliability of the sealing, and has a simple structure, a thin cover plate, and a small occupied space, which ensures the effective space of the miniature battery.

Further, specifically, the end cap, the cylindrical protrusion and the wedge-shaped bead are integrally formed.

Further, specifically, the annular sealing ring, the annular positioning ring and the wedge-shaped positioning ring are integrally formed.

Further, specifically, in order to make the annular sealing ring and the rivet hermetically connected, the inner diameter of the annular sealing ring is D1, the outer diameter of the wedge-shaped protruding ring 12 is d1, the inner diameter of the annular positioning ring is D2, and the annular positioning ring is D2. The outer diameter of the positioning ring is d2, the outer diameter of the wedge-shaped positioning ring is d3, the inner diameter of the annular positioning ring is D2=D1, and the outer diameter d3 of the wedge-shaped positioning ring is slightly smaller than d2.

Further, specifically, in order to facilitate the connection between the battery cover plate and the metal case of the lithium-ion battery, the outer diameter of the end cover is D4, the outer diameter of the annular sealing ring is D5, and the outer diameter of the annular outer ring is D6. The outer diameter of the end cap is D4≤D5≤D6.

Further, specifically, in order to further tightly connect the inner wall of the annular outer ring body with the annular sealing ring, the inner wall of the annular outer ring body extends downward with an arc-shaped protrusion.

As a preference, in order to further connect the battery cover plate with the metal casing of the lithium-ion battery and facilitate installation, an annular flange is provided on the outer periphery of the lower surface of the annular outer ring, and the upper surface of the annular flange is connected to the upper surface of the annular outer ring. The surfaces are flush, and the height of the lower surface of the annular flange is greater than that of the lower surface of the annular outer ring to form a stepped surface.

Further, specifically, the outer diameter d of the lithium-ion battery cover is 5-20 mm, and the thickness h of the lithium-ion battery cover is less than 2 mm.

Further, specifically, in order to ensure the tightness between the rivet and the annular outer ring, the material of the annular sealing ring is an insulating elastic material.

Further, specifically, in order to ensure sufficient metal strength of the lithium-ion battery cover plate, the materials of the rivets and the annular outer ring are both metal materials.

A lithium-ion battery, comprising the lithium-ion battery cover plate and a metal casing as described above. The lithium ion battery of the invention has good sealing performance, high safety performance, simple manufacturing process, is convenient for automatic production, and has low manufacturing cost.

Further, specifically, the metal shell has a hollow cylindrical structure with one end open, the inner cavity of the metal shell is provided with a winding core, and the lithium-ion battery cover is arranged at the opening of the metal shell;

The winding core includes a first current collector and a second current collector, the first current collector is fixedly connected to the metal casing, and the second current collector is fixedly connected to the bottom of the rivet.

Further, specifically, for the firmness of the connection between the lithium-ion battery cover plate and the metal casing, the annular flange is fixedly connected to the opening of the metal casing.

Further, specifically, the winding core is wound and arranged in the inner cavity of the metal casing.

Further, specifically, in order to facilitate the rapid diffusion of heat and the discharge of gas inside the winding core of the lithium-ion battery, the center of the winding core has a through-hole structure, and the through-hole structure is a cylindrical hole.

Preferably, in order to facilitate the assembly of lithium-ion batteries, the diameter of the cylindrical hole is D7, the diameter of the cylindrical hole D7≥d1, and the wedge-shaped bead is located in the through-hole structure.

Preferably, in order to improve the space utilization ratio of the winding core inside the metal shell, a flaring portion is provided at the upper end of the through-hole structure, and the flaring portion gradually expands from bottom to top, and the wedge-shaped bead located in the flared portion.

Further, specifically, the winding core is arranged in the inner cavity of the metal casing in a laminated manner.

Further, specifically, based on the structure of the lithium-ion battery cover plate, the lithium-ion battery also has an explosion-proof pressure relief function at high pressure or high temperature, which improves the safety of the lithium-ion battery. When the lithium-ion battery is working normally, the The air pressure inside the metal shell is air pressure P, and the temperature of the lithium-ion battery is temperature T. When the air pressure inside the metal shell is greater than the air pressure P and/or the temperature is greater than the temperature T, the rivet and the ring The sealing ring forms a gap, or the rivets and the annular sealing ring come off from the annular outer ring.

Further, specifically, in order to avoid the sudden explosion of the lithium-ion battery under the high-voltage condition of the lithium-ion battery, when the air pressure inside the metal casing increases to a first air pressure threshold, and when the first air pressure threshold is greater than the air pressure P, the The annular sealing ring and the annular outer ring are configured to generate a first gap in response to the deformation of the annular outer ring, and the arc protrusion and the wedge-shaped bead are configured to respond to the deformation of the annular outer ring. The deformation of the annular outer ring creates a second gap.

Further, specifically, in order to facilitate the discharge of the air pressure inside the metal shell, when the air pressure inside the metal shell increases from the first air pressure threshold to the second air pressure threshold, the second air pressure threshold is greater than the first air pressure threshold, The rivets and the annular seal ring are configured to form a gap in response to deformation of the annular outer ring, or the rivets and the annular seal ring are configured to form a clearance from the annular outer ring in response to deformation of the annular outer ring. detached from the annular outer ring.

Further, specifically, in order to avoid the sudden explosion of the lithium-ion battery when the lithium-ion battery is highly stable, when the temperature of the lithium-ion battery rises to a first temperature threshold, the first temperature threshold is greater than the temperature T, and the The ring seal is deformed.

Further, specifically, in order to facilitate the discharge of the air pressure inside the metal case, when the temperature of the lithium-ion battery rises to a second temperature threshold, the second temperature threshold is greater than the first temperature threshold, and the rivet and the The annular seal ring is configured to form a gap in response to deformation of the annular seal ring, or the rivet and the annular seal ring are configured to fall off the annular outer ring in response to deformation of the annular seal ring .

Further, specifically, the annular outer ring is bent and deformed from outside to inside to form a cymbal-shaped structure with a bulge in the middle.

Further, specifically, the annular outer ring is bent and deformed from inside to outside to form a conical cap-like structure.

An explosion-proof method for a lithium-ion battery, the lithium-ion battery adopts the lithium-ion battery as described above, and the explosion-proof method for the lithium-ion battery includes: when the internal air pressure of the metal shell is greater than the air pressure P and/or the temperature is greater than the air pressure P At the above temperature T, the rivet and the annular sealing ring form a gap, or the rivet and the annular sealing ring fall off from the annular outer ring, wherein the lithium-ion battery explosion-proof method includes: a high-pressure explosion-proof method and high temperature explosion-proof methods.

Further, specifically, the high-pressure explosion-proof method includes the following steps:

Step S1: When the air pressure inside the metal shell is greater than the air pressure P, the air pressure inside the metal shell will gradually increase, and the air pressure inside the metal shell will diffuse toward the lithium-ion battery cover;

Step S2: When the air pressure inside the metal shell continues to increase to the first air pressure threshold in the step S1, and when the first air pressure threshold is greater than the air pressure inside the metal shell, the annular outer ring due to the pressure area large and the thickness of the annular outer ring is thin, the annular outer ring produces upward bending deformation, the lower sealing layer is partially detached, the connection part between the annular sealing ring and the annular outer ring is detached, and the annular seal A first gap is formed between the ring and the annular outer ring, a second gap is formed between the arc-shaped protrusion and the wedge-shaped bead, and the second gap becomes larger as the internal pressure of the metal shell increases. , the elastic compression rate of the annular sealing ring becomes smaller, the sealing performance of the annular sealing ring becomes smaller, the elastic deformation of the annular sealing ring causes a small amount of gas inside the metal shell to be discharged;

Step S3: when the first air pressure threshold continues to increase to the second air pressure threshold in the step S2, and when the second air pressure threshold is greater than the first air pressure threshold, the annular outer ring continues to bend upwards, The elastic compression rate of the annular sealing ring continues to decrease. When the sealing of the annular sealing ring fails, the lower sealing layer is completely detached, and the connection between the annular sealing ring and the annular outer ring fails. The rivets and A gap is formed between the annular sealing ring and the annular outer ring, or the rivets and the annular sealing ring are ejected from the annular outer ring;

Step S4: In the step S3, the rivet and the annular sealing ring form a gap, or after the rivet and the annular sealing ring are pushed out, the rivet and the annular sealing ring are pushed out from the annular outer ring The upper part is disengaged or completely disengaged, and the gas inside the metal shell is discharged from the gap or the inner ring of the annular outer ring.

Further, specifically, the high temperature explosion-proof method includes the following steps:

Step S11: When the temperature of the lithium-ion battery is greater than the temperature T, the temperature of the lithium-ion battery rises, and the temperature of the lithium-ion battery diffuses toward the cover plate of the lithium-ion battery;

Step S12: In step S11, as the temperature of the lithium-ion battery rises gradually, the annular sealing ring deforms elastically, and the annular sealing ring first softens. When the lithium-ion battery rises to the first temperature threshold , when the first temperature threshold is greater than the temperature T, the annular sealing ring transforms from elastic deformation to plastic deformation, the sealing of the annular sealing ring gradually fails, and a small amount of gas inside the metal shell is discharged;

Step S13: When the temperature of the lithium-ion battery rises to a second temperature threshold, and the second temperature threshold is greater than the first temperature threshold, the gap between the annular sealing ring and the rivets and the annular outer ring If the connection fails, a gap is formed between the rivet and the annular sealing ring and the annular outer ring, or the rivet and the annular sealing ring are ejected from the annular outer ring;

Step S14: The rivet and the annular sealing ring form a gap in the step S13, or after the rivet and the annular sealing ring are pushed out, the rivet and the annular sealing ring are pushed out from the annular outer ring The upper part is disengaged or completely disengaged, and the gas inside the metal shell is discharged from the gap or the inner ring of the annular outer ring.

The beneficial effects of the present invention are as follows:

1. An upper sealing layer is formed between the lower surface of the rivet end cap of the present invention and the upper surface of the annular sealing ring, and a lower sealing layer is formed between the lower surface of the annular sealing ring and the annular outer ring. The different sealing structures block the external water vapor, and ensure the reliability of the sealing under the condition of a relatively simple sealing structure and a small thickness.

2. The present invention matches the slope of the wedge-shaped positioning ring with the slope of the wedge-shaped convex ring, so that the slope of the wedge-shaped positioning ring and the slope of the wedge-shaped convex ring fit closely, which can prevent the leakage of the electrolyte inside the battery, and has both axial ( Vertical direction) and radial direction (horizontal direction) two-way compression, improve the sealing effect, can improve the service life of the battery, and has a simple structure, small volume, can improve the space utilization rate of the micro battery structure.

3. The present invention installs the lithium-ion battery cover plate on the metal shell of the lithium-ion battery. The lithium-ion battery has an explosion-proof and pressure-relieving function, which improves the safety of the battery.

4. The lithium-ion battery of the present invention integrates the sealing function and the explosion-proof function, is ingeniously designed, compact in structure, good in practicability, and high in space utilization.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is a cross-sectional view of a lithium-ion battery cover plate according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view of a lithium-ion battery cover plate A according to an embodiment of the present invention.

Fig. 3 is a schematic structural view of a lithium-ion battery cover plate according to an embodiment of the present invention.

Fig. 4 is a cross-sectional view of a lithium-ion battery according to an embodiment of the present invention.

Fig. 5 is a cross-sectional view of a lithium-ion battery according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view of a lithium-ion battery according to another embodiment of the present invention.

FIG. 7 is a cross-sectional view of a lithium-ion battery according to another embodiment of the present invention.

Fig. 8 is a schematic structural diagram of a lithium-ion battery according to an embodiment of the present invention.

Fig. 9 is a schematic diagram of the deformation of the cover plate of the lithium-ion battery according to the embodiment of the present invention.

Fig. 10 is a schematic diagram of the explosion of the lithium-ion battery according to the embodiment of the present invention.

100 among the figure, lithium-ion battery cover plate, 1, rivet, 10, end cover, 11, cylindrical bump, 12, wedge-shaped protruding ring, 2, annular sealing ring, 20, annular positioning ring, 21, wedge-shaped positioning ring, 3. Annular outer ring, 30. Arc-shaped protrusion, 31. Annular flange, 4. Upper sealing layer, 5. Lower sealing layer, 6. Metal shell, 61. First gap, 7. Rolling core, 71, The first current collector, 72, the second current collector, 8, the through-hole structure, 81, the flaring part.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

In describing the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial", The orientation or positional relationship indicated by "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the referred device or element Must be in a particular orientation, be constructed in a particular orientation, and operate in a particular orientation, and therefore should not be construed as limiting the invention. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, unless otherwise specified, "plurality" means two or more. In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

As shown in Figures 1-3, it is the best embodiment of the present invention, as shown in Figure 1, it is the best embodiment of the present invention, a lithium ion battery cover plate, including: rivet 1, annular sealing ring 2, annular outer Ring 3, upper sealing layer 4 and lower sealing layer 5.

The rivet 1 includes an end cap 10, a cylindrical bump 11 is formed downward at the center of the lower surface of the end cap 10, and a wedge-shaped bead 12 is formed on the outer periphery of the cylindrical bump 11; the material of the rivet 1 is a metal material, including but not limited to stainless steel , carbon steel or aluminum alloy, manufactured by stamping, extrusion, mechanical processing, powder metallurgy and other processing and forming methods, wherein the end cover 10, the cylindrical bump 11 and the wedge-shaped convex ring 12 are integrally formed.

An annular positioning ring 20 extends downwards from the inner ring of the lower surface of the annular sealing ring 2. The central axis of the annular positioning ring 20 is coaxially arranged with the central axis of the annular sealing ring 2. The lower surface of the annular positioning ring 20 extends downwards with a wedge-shaped positioning ring. 21. The material of the annular sealing ring 2 is an insulating elastic material, including but not limited to polypropylene, polyethylene, and PFA plastics, which are formed by injection molding, extrusion, etc., wherein the annular sealing ring 2, the annular positioning ring 20 and the wedge-shaped positioning The ring 21 is integrally formed. In order to ensure the density performance of the annular sealing ring 2, the compression ratio of the annular sealing ring 2 ranges from 40% to 80%, and the sealing effect of the lithium-ion battery cover plate is good.

The annular outer ring 3 is made of metal materials, including but not limited to stainless steel, carbon steel or aluminum alloy, and is manufactured by stamping, extrusion, machining, powder metallurgy and other processing and forming methods.

Specifically, the bottom of the wedge-shaped bead 12 is a plane, the upper surface of the wedge-shaped bead 12 is a slope, and the width gradually becomes wider from top to bottom, the inner ring of the wedge-shaped positioning ring 21 is a slope, the annular positioning ring 20 and the wedge-shaped positioning ring 21 They are all sleeved on the outer circumference of the cylindrical protrusion 11 of the rivet 1, the inner wall of the annular positioning ring 20 is closely attached to the outer wall of the cylindrical protrusion 11, the slope of the wedge-shaped positioning ring 21 matches the slope of the wedge-shaped convex ring 12, and the wedge-shaped positioning The slope of the ring 21 is closely attached to the slope of the wedge-shaped bead 12; the lower surface of the end cover 10 and the upper surface of the annular sealing ring 2 are bonded and fixed, and the lower surface of the rivet 1 The upper sealing layer 4 is formed between them; the upper surface of the upper sealing layer 4 is flush with the lower surface of the end cap 10, so that the sealing performance between the end cap 10 of the rivet 1 and the annular sealing ring 2 is better; the inner wall of the annular outer ring 3 body Sleeved on the outer wall of the annular positioning ring 20, the inner wall of the annular outer ring 3 body is closely attached to the outer wall of the annular positioning ring 20, the lower surface of the annular sealing ring 2 and the annular outer ring 3 are bonded and fixed, and the annular sealing ring 2 A lower sealing layer 5 is formed between the lower surface of the outer ring and the annular outer ring 3 . The water vapor outside the battery, especially under high temperature conditions, will permeate into the inner cavity of the battery case along the sealed path, and the water vapor outside the battery will mix with the internal electrolyte to produce hydrofluoric acid, which will severely damage the battery’s sealing and electrical performance. , the cover plate is provided with two different sealing structures, the upper sealing layer 4 and the lower sealing layer 5, which are used to seal the external water vapor and prevent the external water vapor from entering the inner cavity of the battery case, so as to ensure that the sealing structure is relatively simple and Under the condition of small thickness, the reliability of sealing is ensured. In addition, under high temperature conditions, the electrolyte inside the battery will permeate to the outside of the battery along the sealed path, and the internal electrolyte will mix with external water vapor to produce hydrofluoric acid, which will seriously damage the battery’s sealing and electrical performance. The cylindrical bump 11 compresses and deforms the annular sealing ring 2 to form elastic compression, so as to realize the compression and sealing of the electrolyte.

In some embodiments of the present invention, the wedge-shaped positioning ring 21 can also be pressed against the annular positioning ring 20 by the wedge-shaped protruding ring 12 of the rivet 1 , and the annular positioning ring 20 is partially deformed into the wedge-shaped positioning ring 21 after extrusion.

In the embodiment, the lower surface of the end cap 10 and the upper surface of the annular sealing ring 2 are bonded and fixed by a sealant to form an upper sealing layer 4, and the lower surface of the annular sealing ring 2 and the annular outer ring 3 are bonded and fixed by sealing glue. Connect and fix to form the lower sealing layer 5. The material of the sealant can be rubber, epoxy resin, acrylic ester, etc., preferably materials with good hydrophobicity, good binding ability with plastics and metals, and moderate deformation, etc., to ensure that the battery cover plate is stable. Insulation from external moisture.

In the embodiment, the inner diameter of the annular sealing ring 2 is D1, the outer diameter of the wedge-shaped bead 12 is d1, the inner diameter of the annular positioning ring 20 is D2, the outer diameter of the annular positioning ring 20 is d2, and the outer diameter of the wedge-shaped positioning ring 21 is The diameter is d3, the inner diameter of the annular positioning ring 20 is D2=D1, and the outer diameter d3 of the wedge-shaped positioning ring 21 is slightly smaller than d2. Ring 3 provides support.

In an embodiment, the outer diameter of the end cap 10 is D4, the outer diameter of the annular sealing ring 2 is D5, the outer diameter of the annular outer ring 3 is D6, and the outer diameter of the end cap 10 is D4≤D5≤D6. The outer diameter of the end cap 10 is large, the area of the end cap 10 is also large, and the structural strength is high. The sealing effect between the rings 3 is good, the end cover provides a strong support structure for the lithium-ion battery cover plate, and the top of the end cover 10 will not be affected by external forces to form separation; on the contrary, the outer diameter of the wedge-shaped bead 12 is small, and the bottom of the wedge-shaped bead The area of the lithium-ion battery is small and the structural strength is weak. The lithium-ion battery cover plate 100 is installed on the metal shell 6, and the wedge-shaped collar 12 is installed toward the metal shell. When the internal pressure or temperature of the lithium-ion battery is high, due to the weak structural strength, no The explosion-proof pressure relief function can be formed by adding an explosion-proof structure, and the lithium-ion battery is safe.

In the embodiment, the inner wall of the body of the annular outer ring 3 has an arc-shaped protrusion 30 extending downward, the arc-shaped protrusion 30 is against the outer wall of the wedge-shaped positioning ring 21, and the arc-shaped protrusion 30 is in contact with the outer wall of the wedge-shaped positioning ring 21, It can prevent the main body of the annular outer ring 3 from falling off, and the inclined surface of the wedge-shaped positioning ring 21 expands outwards, and provides an upward support force to the arc-shaped protrusion 30 of the annular outer ring 3 to ensure that the inner wall of the annular outer ring 3 body and the annular sealing ring 2 tightly connected.

In the embodiment, the outer periphery of the lower surface of the annular outer ring 3 is provided with an annular flange 31, the upper surface of the annular flange 31 is flush with the upper surface of the annular outer ring 3, and the height of the lower surface of the annular flange 31 is greater than that of the annular outer ring. The height of the lower surface of 3 forms a stepped surface, which is used to connect with the metal shell 6.

In an embodiment, the outer diameter d of the lithium-ion battery cover is 5-20 mm, the thickness h of the lithium-ion battery cover is less than 2 mm, and the thickness of the annular sealing ring 2 is in the range of 0.1 mm to 0.5 mm, preferably the lithium-ion battery cover The thickness h is less than 1mm, which solves the problem of poor sealing effect of the cover plate with a size below 1mm.

In the embodiment, the lithium-ion battery cover plate assembly method: assemble according to the sequence of the annular outer ring 3, the annular sealing ring 2 and the rivet 1, and press on the periphery of the three-layer structure of the annular outer ring 3, the annular sealing ring 2 and the rivet 1 After tightening, it is processed by riveting. The annular sealing ring 2 is partially deformed by the wedge-shaped convex ring 12, and the inner ring of the annular sealing ring 2 is elastically deformed to form an elastic compression seal. The riveting method can be vertical pressure riveting, radial rotation riveting and Other extrusion or spinning, compared with the traditional riveting structure, the present invention has both axial (vertical direction) and radial (horizontal direction) two-way compression sealing, and the lithium-ion battery cover plate components are few, and the sealing effect is good , the thickness of the cover plate is thin. .

In the embodiment, the upper sealing layer 4 is formed between the lower surface of the end cover 10 of the lithium-ion battery cover plate and the upper surface of the annular sealing ring 2 , and the lower sealing layer 5 is formed between the lower surface of the annular sealing ring 2 and the annular outer ring 3 , Lithium-ion battery cover plate 100 is purposefully provided with two different sealing structures, which block external water vapor, and ensure the reliability of the sealing under the condition that the sealing structure is relatively simple and the thickness is small. In the present invention, the rivets 1 form the supporting structure of the lithium-ion battery cover plate 100 and provide sufficient structural strength. Compared with the existing technology, the compression seal is mainly realized by the deformation and extrusion of the elastic sealing ring in the axial direction. On the premise of ensuring sufficient sealing performance, it must occupy a larger thickness dimension, so that the structure of the lithium-ion battery cover plate can achieve micro-scale In the present invention, the slope of the wedge-shaped positioning ring 21 is matched with the slope of the wedge-shaped bead 12, so that the slope of the wedge-shaped positioning ring 21 and the slope of the wedge-shaped bead 12 fit closely, and the electrolyte inside the battery can be prevented. Leakage, through both axial and radial two-way compression, the effect of compression sealing is greatly improved, the reliability of the seal is increased, the service life of the battery can be improved, and the volume is small, which can improve the space utilization of the micro battery structure Rate.

In an embodiment, as shown in FIG. 4 , the present invention also provides a lithium ion battery, including the lithium ion battery cover plate and a metal casing 6 as described above, and the metal casing 6 is a hollow cylindrical structure with one end open , the inner cavity of the metal casing 6 is provided with a winding core 7 and an electrolyte, the lithium-ion battery cover 100 is arranged at the opening of the metal casing 6, and further, the annular flange 31 is fixedly connected to the opening of the metal casing 6 .

The winding core 7 includes a first current collector 71 and a second current collector 72, the first current collector 71 is fixedly connected to the metal casing 6, and the second current collector 72 is fixedly connected to the bottom of the rivet 1; the winding core 7 is wound and arranged on The inner cavity of the metal shell 6 , or the winding core 7 is stacked in the inner cavity of the metal shell 6 .

In the embodiment, as shown in FIG. 5 , the center of the wound-type winding core 7 has a through-hole structure 8, and the lithium-ion battery cover plate 100 is covered on the metal case 6. The through-hole structure 8 is conducive to lithium ion battery. Rapid diffusion of heat and gas discharge inside the battery core, and when the lithium-ion battery is used abnormally, due to the through-hole structure in the center of the core 7, the core 7 will not splash out when the battery explodes.

In one embodiment of the present invention, as shown in FIG. 6, the through-hole structure 8 can be a cylindrical hole, the diameter of the cylindrical hole is D7, and the diameter of the cylindrical hole D7≥d1, the lithium-ion battery cover plate 100 The wedge-shaped protruding ring 12 at the bottom is arranged in the through-hole structure 8, the assembly process is simple and easy to manufacture, but the space utilization rate is low.

In another embodiment of the present invention, in order to improve the utilization rate of space, as shown in FIG. The diameter at the larger end of the flared portion 81 is D8, the diameter of the smaller end of the flared portion 81 is D9, the diameter of the larger end of the flared portion 81 is D8>D3, and the diameter of the smaller end of the flared portion 81 is D9 <d1, so that the wedge-shaped bead 12 is installed in the flaring portion 81, and the space utilization rate is high.

In practical application, the rivet 1 is the first metal cover of the lithium-ion battery, and the annular outer ring 3 is the second metal cover of the lithium-ion battery. Generally, the first metal cover is the positive electrode of the lithium-ion battery, and the second metal cover is the positive electrode of the lithium-ion battery. The second metal cover is the negative electrode of the lithium-ion battery. The first metal cover and the second metal cover are respectively provided with a positive electrode mark and a negative electrode mark for welding personnel to distinguish, further reducing welding difficulty.

The manufacturing method of the lithium-ion battery includes: welding and fixing the bottom of the rivet 1 of the assembled lithium-ion battery to the second current collector 72, placing the winding core 7 in the inner cavity of the metal shell 6, and connecting the bottom of the metal shell 6 to the second current collector 72. A current collector 71 is welded and connected, and the annular flange 31 of the annular outer ring 3 is connected to the opening of the metal case 6 by laser welding. The completed lithium-ion battery is shown in FIG. 8 .

In related technologies, in order to avoid internal thermal runaway caused by internal pressure rise and explosion caused by internal manufacturing defects or abuse by users, an explosion-proof pressure relief structure is generally provided to ensure that lithium-ion batteries are used during long-term use or during thermal runaway. When the internal air pressure rises excessively, the pressure can be released in time to protect personal and property safety. In the prior art, commonly used explosion-proof and pressure-relief structures can be divided into the following two categories: one is a type-type explosion-proof and pressure-relief structure, which is generally applied to the design of a cylindrical lithium-ion battery cover plate, and generally has the functions of both current interruption and pressure relief. However, the disadvantage of this type of structure is that the structure is complex, there are many parts and the assembly is complicated, and it takes up a lot of space and it is difficult to install it in a micro-small battery; the other is an engraved explosion-proof pressure relief structure, which requires very high processing accuracy for the engraved groove. , and it is only suitable for grooving on metals with low hardness and good ductility, such as aluminum alloy, etc., but it is difficult to ensure low burst pressure for carbon steel, stainless steel or other alloys with high hardness Reliable groove processing is performed, and due to the limitation of the use environment, it is impossible to provide sufficient deformation space to realize the function of explosion-proof and pressure relief. The invention can also solve the problem that it is difficult to install an effective pressure relief and explosion-proof structure due to the space limitation of the current micro-small battery

In the embodiment, as shown in Figures 9-10, when the lithium-ion battery is working normally, the air pressure inside the metal casing (6) is air pressure P, and the temperature of the lithium-ion battery is temperature T. Under the circumstances, the internal heat is out of control or causes the internal pressure to rise, making the lithium-ion battery work abnormally. When the internal pressure of the metal shell 6 is greater than the air pressure P and/or the temperature is greater than the temperature T, the rivet 1 of the lithium-ion battery cover plate 100 of the present invention A gap is formed with the annular sealing ring 2, or the rivet 1 and the annular sealing ring 2 fall off from the annular outer ring 3. Since the annular outer ring 3 will not be separated from the metal shell 6, and the annular outer ring 3 will not fly out, the explosion and splashing of the winding core 7 and the electrolyte in the inner cavity of the metal shell 6 are avoided, and no additional structural space and manufacturing The process makes the lithium-ion battery have the function of explosion-proof and pressure relief.

In the embodiment, when the air pressure inside the metal shell increases to the first air pressure threshold, and the first air pressure threshold is greater than the air pressure P, the space between the annular sealing ring 2 and the annular outer ring 3 is configured to respond to the deformation of the annular outer ring 3 The first gap 61 is generated, and the arc-shaped protrusion 30 and the wedge-shaped bead 12 are configured to generate a second gap in response to the deformation of the annular outer ring 3; further, when the internal pressure of the metal shell is from the first pressure threshold Increase to the second air pressure threshold, when the second air pressure threshold is greater than the first air pressure threshold, the rivet 1 and the annular sealing ring 2 are configured to form a gap in response to the deformation of the annular outer ring 3, or the rivet 1 and the annular sealing ring 2 are configured to It is configured to fall off from the annular outer ring 3 in response to deformation of the annular outer ring 3 . Further, the annular outer ring 3 is bent from outside to inside to form a cymbal-shaped structure with a bulge in the middle, or the annular outer ring 3 is bent from inside to outside to form a cone-shaped cover-like structure.

When the temperature of the lithium-ion battery rises to the first temperature threshold, the first temperature threshold is greater than the temperature T, and the annular sealing ring 2 is deformed; further, when the temperature of the lithium-ion battery rises to the second temperature threshold, the second temperature threshold is greater than the first temperature threshold A temperature threshold, the rivet 1 and the annular seal ring 2 are configured to form a gap in response to the deformation of the annular seal ring 2, or the rivet 1 and the annular seal ring 2 are configured to displace the annular outer ring in response to the deformation of the annular seal ring 2 3 on fall off.

In an embodiment, the present invention also provides a lithium-ion battery explosion-proof method, the lithium-ion battery adopts the above-mentioned lithium-ion battery, and the lithium-ion battery explosion-proof method includes when the internal pressure of the metal shell 6 is greater than the pressure P and/or Or when the temperature is higher than the temperature T, the rivet 1 and the annular sealing ring 2 form a gap, or the rivet 1 and the annular sealing ring 2 fall off from the annular outer ring 3, wherein the lithium-ion battery explosion-proof methods include: high-pressure explosion-proof methods and high-temperature explosion-proof methods.

In an embodiment of the present invention, the high-pressure explosion-proof method includes the following steps:

Step S1: When the internal air pressure of the metal shell 6 is greater than the air pressure P, the internal air pressure of the metal shell 6 will gradually increase, and the internal air pressure of the metal shell 6 will diffuse toward the lithium-ion battery cover;

Step S2: When the air pressure inside the metal shell 6 continues to increase to the first air pressure threshold in step S1, and when the first air pressure threshold is greater than the air pressure inside the metal shell 6, the annular outer ring 3 has a large pressure area and the thickness of the annular outer ring 3 Thin, and the annular outer ring is close to the inside of the metal shell 6, the annular outer ring 3 produces upward bending deformation, and the lower sealing layer 5 connected between the annular outer ring 3 and the annular sealing ring 2 is partially separated, resulting in the annular sealing ring 2 and the annular The connecting part between the outer rings 3 is disengaged, the first gap 61 is formed between the annular sealing ring 2 and the annular outer ring 3, and the second gap is formed between the arc-shaped protrusion 30 and the wedge-shaped protruding ring 12, along with the metal shell 6. As the internal air pressure increases, the second gap becomes larger, the elastic compression rate of the annular sealing ring 2 becomes smaller, and the sealing performance of the annular sealing ring 2 becomes smaller (the sealing performance becomes worse with the increase of the air pressure), and a small amount of gas inside the metal shell 6 discharge;

In step S2, when the annular outer ring is bent and deformed, since the arc-shaped protrusion 30 is opposed to the annular positioning ring 20, the arc-shaped protrusion 30 is connected to the annular positioning ring 20 more closely due to the upward action of the internal pressure of the metal shell, and the wedge-shaped The positioning ring 21 provides support for the arc-shaped protrusion 30, and the annular sealing ring 2 can also be connected with the annular outer ring 3. The rivet 1 is fixed on the annular sealing ring 2, and the rivet 1 and the annular sealing ring 2 will not be connected to the annular outer ring for the time being. The ring 3 is separated, but as the internal pressure of the metal shell 6 increases, the second gap becomes larger, the elastic compression rate of the annular seal ring 2 becomes smaller, the sealing performance of the annular seal ring 2 becomes smaller, and the gas inside the metal shell 6 becomes smaller. Due to the small discharge of internal gas, lithium-ion batteries can avoid continuous increase in internal pressure, reduce the risk of battery explosion, and further improve the safety and stability of lithium-ion batteries.

Step S3: When the first air pressure threshold continues to increase to the second air pressure threshold in step S2, and the second air pressure threshold is greater than the first air pressure threshold, the annular outer ring 3 continues to produce upward bending deformation, and the elastic compressibility of the annular sealing ring 2 continues to decrease , when the sealing of the annular sealing ring 2 fails, the lower sealing layer 5 is completely detached, the connection between the annular sealing ring 2 and the annular outer ring 3 fails, and a gap is formed between the rivet 1 and the annular sealing ring 2 and the annular outer ring 3, or the The rivet 1 and the annular sealing ring 2 are ejected from the annular outer ring 3;

Step S4: In step S3, the rivet 1 and the annular sealing ring 2 form a gap, or after the rivet 1 and the annular sealing ring 2 are pushed out, the rivet 1 and the annular sealing ring 2 are partially or completely separated from the annular outer ring 3, and the metal shell The gas inside the body 6 is discharged from the gap or the inner ring of the annular outer ring 3 to prevent the metal shell 6 of the lithium-ion battery from exploding due to excessive air pressure, and quickly release the pressure of the lithium-ion battery.

When the lithium-ion battery of the present invention applies pressure to the rivet 1 from the outside, the rivet 1 is carried by the annular sealing ring 2 and the annular outer ring 3, which ensures a greater bonding force, and the sealing structure of the lithium-ion battery cover plate 100 changes little, and the sealing The performance will not be affected by the extrusion force of external force. On the contrary, when the internal pressure of the metal casing 6 of the lithium-ion battery becomes larger, the annular outer ring 3 will be squeezed and deformed by the internal pressure, and the rivet 1 and the annular sealing ring 2 are configured to respond The deformation of the annular outer ring 3 forms a gap or falls off from the annular outer ring 3, and the gas is discharged from the gap or the inner ring of the annular outer ring 3. Since the annular outer ring 3 will not be separated from the metal shell 6, and the annular outer ring 3 It will not fly out, avoiding the explosion and splashing of the winding core 7 and the electrolyte in the inner cavity of the metal shell 6, without adding additional structural space and manufacturing processes, so that the lithium-ion battery has an explosion-proof and pressure-relieving function.

In yet another embodiment of the present invention, the high temperature explosion-proof method comprises the following steps:

Step S11: When the temperature of the lithium-ion battery is greater than the temperature T, the temperature of the lithium-ion battery rises, and the temperature of the lithium-ion battery diffuses toward the cover plate of the lithium-ion battery;

In step S11, the temperature of the lithium-ion battery will rise due to internal or external short circuit, abnormal charge and discharge, use environment (such as: use at abnormal high temperature) or storage environment, etc. High temperature phenomenon.

Step S12: As the temperature of the lithium-ion battery rises gradually, the annular sealing ring 2 is elastically deformed, and the annular sealing ring 2 first softens. When the lithium-ion battery rises to the first temperature threshold and the first temperature threshold is greater than the temperature T, the annular sealing ring 2 The sealing ring 2 changes from elastic deformation to plastic deformation, the annular sealing ring 2 gradually loses its sealing effect, and a small amount of gas inside the metal shell (6) is discharged;

In step S12, the first temperature threshold is the softening value of the annular sealing ring 2. Since the annular sealing ring 2 is compressed and elastically deforms to form a compressed seal, the annular sealing ring 2 will gradually change from the compressed elastic deformation when it reaches the softening value. Transformed into plastic deformation, the annular sealing ring 2 gradually fails to seal, the rivet 1 and the annular outer ring are connected with the annular sealing ring 2 to form a partial separation, and a small gap will be formed between the rivet 1 and the annular sealing ring 2, or the annular seal A small gap is formed between the ring 2 and the annular outer ring 3, and a small amount of gas inside the metal shell is discharged from the small gap. Due to the small amount of internal gas discharge of the lithium-ion battery, the continuous increase of the internal pressure can be avoided, which reduces the battery life. The risk of explosion further improves the safety and stability of lithium-ion batteries.

Step S13: When the temperature of the lithium-ion battery rises to the second temperature threshold, and the second temperature threshold is greater than the first temperature threshold, the connection between the annular sealing ring 2 and the rivet 1 and the annular outer ring 3 fails, and the annular sealing ring 2 and the Separation is formed between the rivet 1 and the annular outer ring 3, and a gap is formed between the rivet 1 and the annular sealing ring 2 and the annular outer ring 3, or the rivet 1 and the annular sealing ring 2 are ejected from the annular outer ring 3;

In step S13, the second temperature threshold is greater than the first temperature threshold, the second temperature threshold is the melting point value of the annular sealing ring 2, and the melting point value is less than 200°C, the annular sealing ring 2 will be completely melted due to reaching the melting point value, and the annular seal The connection between the ring 2 and the rivet 1 and the annular outer ring 3 fails, and the annular sealing ring 2 will melt, and the annular sealing ring 2 is bonded to the annular outer ring 3, and the rivet 1 and the annular sealing ring 2 are connected to the annular outer ring. 3 to form a gap, or the rivet 1 and the annular sealing ring 2 are directly ejected from the annular outer ring 3 due to the excessive internal pressure of the metal shell 6 .

Step S14: In step S13, the rivet 1 and the annular sealing ring 2 form a gap, or after the rivet 1 and the annular sealing ring 2 are ejected, the rivet 1 and the annular sealing ring 2 are partially or completely separated from the annular outer ring 3, and the metal shell The gas inside the body 6 is discharged from the gap or the inner ring of the annular outer ring 3;

In step S14, the gas inside the metal casing 6 can be discharged from the gap, or from the inner ring of the annular outer ring 3, and the discharge speed is fast to avoid battery explosion, and the winding core 7 in the inner cavity of the metal casing 6 and the electrolytic Liquid explosion splash.

In the embodiment, the chronic high pressure produced under mild conditions and the acute high pressure produced under severe conditions by the lithium-ion battery of the present invention all have the function of explosion-proof and pressure relief, but the high-pressure explosion-proof method is used to realize explosion-proof and pressure relief during chronic high pressure. Acute high pressure generated under severe conditions uses high-temperature explosion-proof to achieve explosion-proof pressure relief, but in actual use, under severe conditions, high temperature and high pressure exist at the same time. When the temperature of the lithium-ion battery is too high, the internal air pressure of the metal shell 6 It will inevitably rise, so there will be two methods of high-pressure explosion-proof and high-temperature explosion-proof, to achieve a more effective and rapid pressure relief and exhaust effect, because the annular outer ring 3 will not be separated from the metal shell 6, and the annular outer ring 3 will not fly out, avoiding the explosion and splashing of the winding core 7 and the electrolyte in the inner cavity of the metal shell 6, without adding additional structural space and manufacturing processes, so that the lithium-ion battery has an explosion-proof pressure relief function, which improves the lithium-ion battery. safety.

The lithium-ion battery cover plate 100 of the present invention is installed on the metal shell 6, and integrates the sealing function, the high-pressure explosion-proof function and the high-temperature explosion-proof function into one, and the design fits ingeniously, with compact structure, good practicability, high space utilization rate, and high safety. , the manufacturing process is simple, it is convenient for automatic production, and the manufacturing cost is low.

Inspired by the above-mentioned ideal embodiment according to the present invention, through the above-mentioned description content, relevant workers can make various changes and modifications within the scope of not departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, but must be determined according to the scope of the claims.

Claims (28)

1. A lithium ion battery cover plate, characterized in that it comprises: rivets (1), annular sealing ring (2), annular outer ring (3), upper sealing layer (4) and lower sealing layer (5);

   The rivet (1) includes an end cap (10), a cylindrical protrusion (11) is formed downward at the center of the lower surface of the end cap (10), and a wedge-shaped protrusion (11) is formed on the outer periphery of the cylindrical protrusion (11). convex ring (12);

   An annular positioning ring (20) extends downward from the inner ring of the lower surface of the annular sealing ring (2), and the central axis of the annular positioning ring (20) is coaxially arranged with the central axis of the annular sealing ring (2), A wedge-shaped positioning ring (21) extends downward from the lower surface of the annular positioning ring (20);

   The bottom of the wedge-shaped bead (12) is a plane, the upper surface of the wedge-shaped bead (12) is a slope, and the width gradually becomes wider from top to bottom, and the inner ring of the wedge-shaped positioning ring (21) is a slope, The annular positioning ring (20) and the wedge-shaped positioning ring (21) are both sleeved on the outer periphery of the cylindrical protrusion (11) of the rivet (1), and the inner wall of the annular positioning ring (20) is in contact with the The outer wall of the cylindrical protrusion (11) is closely attached, the slope of the wedge-shaped positioning ring (21) is matched with the slope of the wedge-shaped convex ring (12), and the slope of the wedge-shaped positioning ring (21) is matched with the slope of the wedge-shaped positioning ring (21). The slope of the wedge-shaped bead (12) is closely fitted; the lower surface of the end cover (10) is bonded and fixed to the upper surface of the annular sealing ring (2), and the rivet (1) end cover (10) The upper sealing layer (4) is formed between the lower surface of the ring sealing ring (2) and the upper surface;

   The inner wall of the annular outer ring (3) body is sleeved on the outer wall of the annular positioning ring (20), and the inner wall of the annular outer ring (3) body is closely attached to the outer wall of the annular positioning ring (20) , the lower surface of the annular sealing ring (2) and the annular outer ring (3) are bonded and fixed, and the lower surface of the annular sealing ring (2) and the annular outer ring (3) form a The lower sealing layer (5).
2. The lithium-ion battery cover plate according to claim 1, characterized in that, the end cover (10), the cylindrical protrusion (11) and the wedge-shaped bead (12) are integrally formed.
3. The lithium-ion battery cover plate according to claim 1, characterized in that, the annular sealing ring (2), the annular positioning ring (20) and the wedge-shaped positioning ring (21) are integrally formed.
4. Lithium-ion battery cover plate as claimed in claim 3, it is characterized in that, the inner diameter of described annular sealing ring (2) is D1, the outer diameter of described wedge-shaped bead (12) is d1, and described annular positioning ring ( 20) the inner diameter is D2, the outer diameter of the annular positioning ring (20) is d2, the outer diameter of the wedge-shaped positioning ring (21) is d3, and the inner diameter of the annular positioning ring (20) is D2=D1, so The outer diameter d3 of the wedge-shaped positioning ring (21) is slightly smaller than d2.
5. The lithium-ion battery cover plate according to claim 3, wherein the outer diameter of the end cover (10) is D4, the outer diameter of the annular sealing ring (2) is D5, and the outer diameter of the annular outer ring (3) The outer diameter is D6, and the outer diameter of the end cap (10) is D4≤D5≤D6.
6. The lithium-ion battery cover plate according to claim 1, characterized in that, arc-shaped protrusions (30) extend downwards from the inner wall of the body of the annular outer ring (3).
7. Lithium-ion battery cover plate as claimed in claim 1, it is characterized in that, the outer circumference of the lower surface of the annular outer ring (3) is provided with an annular flange (31), and the upper surface of the annular flange (31) is in contact with the annular The upper surface of the outer ring (3) is flush, and the height of the lower surface of the annular flange (31) is greater than the height of the lower surface of the annular outer ring (3) to form a stepped surface.
8. Lithium-ion battery cover plate as claimed in claim 1, is characterized in that, the outer diameter d of described lithium-ion battery cover plate (100) is 5-20mm, and the thickness h of described lithium-ion battery cover plate (100) is less than 2mm.
9. The lithium-ion battery cover plate according to claim 1, characterized in that, the annular sealing ring (2) is made of insulating elastic material.
10. The lithium ion battery cover plate according to claim 1, characterized in that, the materials of the rivet (1) and the annular outer ring (3) are both metal materials.
11. A lithium-ion battery, characterized in that it comprises the lithium-ion battery cover plate and a metal casing (6) according to any one of claims 1-10.
12. The lithium ion battery according to claim 11, characterized in that, the metal casing (6) is a hollow cylindrical structure with one end open, and the inner cavity of the metal casing (6) is provided with a winding core (7) , the lithium-ion battery cover plate is arranged at the opening of the metal casing (6);

    The winding core (7) includes a first current collector (71) and a second current collector (72), the first current collector (71) is fixedly connected to the bottom of the metal shell (6), and the first Two current collectors (72) are fixedly connected with the bottom of the rivet (1).
13. The lithium ion battery according to claim 12, characterized in that, the annular flange (31) is fixedly connected to the opening of the metal casing (6).
14. The lithium ion battery according to claim 12, characterized in that, the winding core (7) is wound and arranged in the inner cavity of the metal casing (6).
15. The lithium ion battery according to claim 14, characterized in that, the core (7) has a through-hole structure (8) in the center, and the through-hole structure is a columnar hole.
16. The lithium-ion battery according to claim 15, wherein the diameter of the cylindrical hole is D7, the diameter of the cylindrical hole D7≥d1, and the wedge-shaped bead (12) is located in the through-hole structure (8).
17. The lithium ion battery according to claim 15, characterized in that, the upper end of the through-hole structure (8) is provided with a flared portion (81), and the flared portion (81) gradually expands from bottom to top, The wedge-shaped bead (12) is located in the flared portion (81).
18. The lithium ion battery according to claim 12, characterized in that, the winding core (7) is stacked in the inner cavity of the metal casing (6).
19. The lithium-ion battery according to claim 12, characterized in that, when the lithium-ion battery is in normal operation, the internal air pressure of the metal shell (6) is air pressure P, and the temperature of the lithium-ion battery is temperature T. When the internal air pressure of the metal shell (6) is greater than the air pressure P and/or the temperature is greater than the temperature T, the rivet (1) and the annular sealing ring (2) form a gap, or the rivet (1) And the annular sealing ring falls off from the annular outer ring (3).
20. The lithium ion battery according to claim 19, wherein when the air pressure inside the metal casing increases to a first air pressure threshold, and when the first air pressure threshold is greater than the air pressure P, the annular sealing ring ( 2) and the annular outer ring (3) are configured to generate a first gap (61) in response to the deformation of the annular outer ring (3), the arc-shaped protrusion (30) and the wedge-shaped The flanges (12) are configured to create a second gap in response to deformation of said annular outer ring (3).
21. The lithium ion battery according to claim 20, wherein when the air pressure inside the metal casing increases from a first air pressure threshold to a second air pressure threshold, and the second air pressure threshold is greater than the first air pressure threshold , the rivet (1) and the annular sealing ring (2) are configured to form a gap in response to the deformation of the annular outer ring (3), or the rivet (1) and the annular sealing ring (2) ) is configured to fall off from the annular outer ring (3) in response to deformation of the annular outer ring (3).
22. The lithium-ion battery according to claim 19, wherein when the temperature of the lithium-ion battery rises to a first temperature threshold, the first temperature threshold is greater than the temperature T, and the annular sealing ring (2) deformed.
23. The lithium-ion battery according to claim 22, wherein when the temperature of the lithium-ion battery rises to a second temperature threshold, the second temperature threshold is greater than the first temperature threshold, and the rivet (1) and the annular sealing ring (2) are configured to form a gap in response to the deformation of the annular sealing ring (2), or the rivet (1) and the annular sealing ring (2) are configured to respond to the deformation of the annular sealing ring (2). Due to the deformation of the annular sealing ring (2), it falls off from the annular outer ring (3).
24. The lithium-ion battery according to claim 21, characterized in that, the annular outer ring (3) is bent and deformed from outside to inside to form a cymbal-shaped structure with a bulge in the middle.
25. The lithium ion battery according to claim 21, characterized in that, the annular outer ring (3) is bent and deformed from inside to outside to form a cone-shaped cover-like structure.
26. A lithium-ion battery explosion-proof method, characterized in that the lithium-ion battery uses the lithium-ion battery according to claims 12-25, and the lithium-ion battery explosion-proof method comprises: when the inside of the metal casing (6) When the air pressure is greater than the air pressure P and/or the temperature is greater than the temperature T, the rivet (1) and the annular sealing ring (2) form a gap, or the rivet (1) and the annular sealing ring (2) ) falls off from the annular outer ring (3), wherein the lithium-ion battery explosion-proof method includes: a high-pressure explosion-proof method and a high-temperature explosion-proof method.
27. The explosion-proof method for lithium-ion batteries according to claim 26, wherein the high-voltage explosion-proof method comprises the following steps:

    Step S1: When the internal air pressure of the metal shell (6) is greater than the air pressure P, the internal air pressure of the metal shell (6) will gradually increase, and the internal air pressure of the metal shell (6) will flow toward the lithium ion Diffusion in the direction of the battery cover;

    Step S2: When the internal air pressure of the metal shell (6) in the step S1 continues to increase to the first air pressure threshold, and when the first air pressure threshold is greater than the internal air pressure of the metal shell (6), the ring Due to the large pressure area of the outer ring (3) and the thin thickness of the annular outer ring (3), the annular outer ring (3) is bent upwards, the lower sealing layer (5) is partially separated, and the annular outer ring (3) is partially detached. The connection part between the sealing ring (2) and the annular outer ring (3) is disengaged, a first gap (61) is formed between the annular sealing ring (2) and the annular outer ring (3), and the arc A second gap is formed between the shaped protrusion (30) and the wedge-shaped bead (12), and as the internal air pressure of the metal casing (6) increases, the second gap becomes larger, and the annular sealing ring (2 ) the elastic compression rate becomes smaller, the sealing performance of the annular sealing ring (2) becomes smaller, the elastic deformation of the annular sealing ring (2), and a small amount of gas inside the metal shell (6) are discharged;

    Step S3: When the first air pressure threshold continues to increase to the second air pressure threshold in the step S2, and when the second air pressure threshold is greater than the first air pressure threshold, the annular outer ring (3) continues to generate upward bending deformation, the elastic compression rate of the annular sealing ring (2) continues to decrease, and when the sealing of the annular sealing ring (2) fails, the lower sealing layer (5) is completely detached, and the annular sealing ring ( 2) The connection with the annular outer ring (3) fails, and a gap is formed between the rivet (1) and the annular sealing ring (2) and the annular outer ring (3), or the rivet (1) and the annular sealing ring (2) are ejected from the annular outer ring (3);

    Step S4: In the step S3, the rivet (1) and the annular sealing ring (2) form a gap, or after the rivet (1) and the annular sealing ring (2) are ejected, the rivet (1) and the annular sealing ring (2) are partly or completely separated from the annular outer ring (3), and the gas inside the metal casing (6) is released from the gap or the annular outer ring (3) ) of the inner ring discharge.
28. The explosion-proof method for lithium-ion batteries according to claim 26, wherein the high-temperature explosion-proof method comprises the following steps:

    Step S11: When the temperature of the lithium-ion battery is greater than the temperature T, the temperature of the lithium-ion battery rises, and the temperature of the lithium-ion battery diffuses toward the cover plate of the lithium-ion battery;

    Step S12: In step S11, as the temperature of the lithium-ion battery rises gradually, the annular sealing ring (2) deforms elastically, and the annular sealing ring (2) softens first, when the lithium-ion battery rises When the first temperature threshold is reached, when the first temperature threshold is greater than the temperature T, the annular sealing ring (2) transforms from elastic deformation to plastic deformation, and the sealing of the annular sealing ring (2) gradually fails, and the A small amount of gas inside the metal shell (6) is discharged;

    Step S13: When the temperature of the lithium-ion battery rises to a second temperature threshold, and the second temperature threshold is greater than the first temperature threshold, the annular sealing ring (2) and the rivet (1) and the If the connection between the annular outer ring (3) fails, a gap is formed between the rivet (1) and the annular sealing ring (2) and the annular outer ring (3), or the rivet (1) and the annular sealing ring (2) is ejected from the annular outer ring (3);

    Step S14: In the step S13, the rivet (1) and the annular sealing ring (2) form a gap, or after the rivet (1) and the annular sealing ring (2) are pushed out, the rivet (1) and the annular sealing ring (2) are partly or completely separated from the annular outer ring (3), and the gas inside the metal casing (6) is released from the gap or the annular outer ring (3) ) of the inner ring discharge.

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