TWM595334U - Cover plate assembly for lithium ion battery and lithium ion battery - Google Patents

Abstract

This creation discloses a cover assembly for a lithium ion battery and a lithium ion battery. The cover plate assembly includes: a cover plate body with a through hole in the middle of the cover plate body, the through hole extending to form a cylinder body, the cylinder body protruding from at least one surface of the cover plate body; a pressure relief portion, the pressure relief The portion is located in the cylinder body and is sealingly connected to the cylinder body, the pressure relief portion is in a ring shape, the pressure relief portion is configured to generate a crack or fall off from the cover plate body in response to deformation of the cover plate body; and the center conductor , The center conductor is disposed in the inner ring of the pressure relief portion, and penetrates the pressure relief portion in the axial direction. The cover plate assembly has good safety performance and takes up little space.

Description

Cover plate assembly for lithium ion battery and lithium ion battery

This creation relates to the technical field of energy conversion, and more specifically, to a cover plate assembly for a lithium ion battery and a lithium ion battery.

Existing lithium-ion batteries, especially high-power power lithium-ion batteries, have been designed with an explosion-proof pressure relief structure or device to ensure that the lithium-ion battery can be timely when the internal air pressure rises excessively during long-term use or thermal runaway. Pressure relief to prevent an explosion.

In some technical solutions, the cap has an explosion-proof pressure relief function. The cap includes an upper cover, a lower cover, and a bursting membrane located between the upper cover and the lower cover. When the internal air pressure exceeds the rated value, the rupture diaphragm is ruptured to release the pressure. The pressure relief structure is usually used in the cover plate of a cylindrical lithium ion battery. The pressure-relief structure has the functions of flow cutoff and pressure relief. But the disadvantage is that the structure is complicated, the parts are more complicated to assemble, and the space occupied by the height is larger, and the space utilization rate of the battery core is low.

Therefore, it is necessary to provide a new technical solution to solve the above technical problems.

One purpose of this creation is to provide a new technology solution for the lid assembly of lithium ion batteries.

According to the first embodiment of the present creation, a cover plate assembly for a lithium ion battery is provided. The cover plate assembly includes: a cover plate body with a through hole in the middle of the cover plate body, the through hole extending to form a cylindrical body protruding from at least one surface of the cover plate body; a pressure relief portion, the The pressure relief portion is located in the cylinder body and is sealingly connected to the cylinder body, the pressure relief portion has a ring shape, the pressure relief portion is configured to generate a crack or fall off from the cover plate body in response to deformation of the cover plate body; and The center conductor is provided in the inner ring of the pressure relief portion and penetrates the pressure relief portion in the axial direction.

In some embodiments, the pressure relief is an inorganic non-metallic material.

In some embodiments, the material of the pressure relief portion is glass or ceramic.

In some embodiments, the barrel protrudes from one of the surfaces of the cover plate body, and the cover plate body, the pressure relief portion, and the side of the center conductor opposite to the barrel are flush.

In some embodiments, the cover plate body and the center conductor respectively serve as an electrode of a lithium ion battery, and the pressure relief portion includes an extension portion covering an end surface of the free end of the barrel.

In some embodiments, the outer edge of the cover plate body extends to one side to form an annular connection.

In some embodiments, the barrel is perpendicular to the cover plate body.

In some embodiments, a portion of the cylinder body connected to the cover plate body is defined as a root, and an outer chamfer is formed outside the root.

In some embodiments, a portion of the cylinder body connected to the cover plate body is defined as a root, an inner chamfer is formed inside the root, and the pressure relief portion is filled in an area surrounded by the inner chamfer.

In some embodiments, the center conductor protrudes from at least one end surface of the pressure relief portion.

In some embodiments, an insulating layer is provided on the outer surface of the cover plate, the insulating layer covers the upper end surface of the pressure relief portion, and the upper end surface of the center conductor is bare.

According to another embodiment of the present invention, a lithium ion battery is improved. The lithium ion The sub-battery includes: an energy conversion element; a case, the case including a cylindrical portion, the energy conversion element is located in a cavity enclosed by the cylindrical portion; and the above-mentioned cover plate assembly, the cover plate body covers the barrel At one end of the shape, the cover plate body and the center conductor are respectively connected to the two electrodes of the energy conversion element.

In some embodiments, the cylinder of the cover plate assembly protrudes into the cavity, and the energy conversion element forms a concave structure at a location corresponding to the cylinder and the pressure relief portion.

In some embodiments, a gap is formed between the center conductor and the recessed structure, the center conductor is connected to an electrode of the energy conversion element through a tab, and the tab forms a retractable structure within the gap.

According to yet another embodiment of the present invention, a lithium ion battery is improved. The lithium-ion battery includes: an energy conversion element; a case, the case including a cylindrical portion, the energy conversion element is located in the cylindrical portion; and the above-mentioned cover plate assembly, the cover plate body covers the cylindrical portion At one end, the cover plate body and the center conductor are respectively connected to the two electrodes of the energy conversion element; the end of the cylindrical portion forms an inwardly closed portion, and the ring-shaped connecting portion is sleeved on the outside of the closed portion.

According to an embodiment of the present invention, since the cover plate body, the pressure relief portion, and the center conductor are on the same layer, they have a smaller thickness and occupy less space in the height direction. Compared with the multi-layer cover plate assembly, the structure is simple and the assembly is easier.

In addition, the pressure relief part can play the role of pressure relief, improving the safety performance of the lithium ion battery.

In addition, the center conductor has a conduction function, and the cover plate assembly can be used as at least one electrode of the lithium ion battery.

In addition, a better sealing connection can be formed between the cylinder and the pressure relief part, which The invention has good sealing effect under the condition that the thickness of the cover plate body is small, and is suitable for small energy storage elements such as needle batteries and button batteries.

Through the following detailed description of the exemplary embodiments of the present creation with reference to the drawings, other features and advantages of the present creation will become clear.

11: Cover body

12: Pressure relief

13: Center conductor

14: clearance

15: cylinder

16: Insulation

19: battery cell

20: Center column

21: Extension

22: Scalable structure

23: Ring connection

24: cylindrical part

25: bottom

26: Closing Department

R1: outer chamfer

R2: inner chamfer

b: straight section

The drawings incorporated in and forming a part of the specification show embodiments of the present creation, and are used to explain the principle of the present creation together with the description thereof.

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

FIG. 2 is a schematic cross-sectional view of a second cover plate assembly of a lithium-ion battery according to an embodiment of the present invention.

3 is a schematic cross-sectional view of a third cover plate assembly of a lithium-ion battery according to an embodiment of the present invention.

4 is a schematic cross-sectional view of a fourth cover plate assembly of a lithium-ion battery according to an embodiment of the present invention.

FIG. 5 is an assembly diagram of a cover assembly and a housing of a lithium-ion battery according to an embodiment of the present invention.

6-7 are schematic cross-sectional views of another embodiment of the lithium ion battery of the present invention.

Various exemplary embodiments of the present creation will now be described in detail with reference to the drawings. It should be noted that the relative arrangement of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of this creation unless specifically stated otherwise.

The following description of at least one exemplary embodiment is actually merely illustrative, and in no way serves as any limitation on the creation and its application or use.

Techniques, methods and equipment known to those of ordinary skill in the related art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the specification.

In all embodiments shown and discussed herein, any specific values should be interpreted as exemplary only, and not as limitations. Therefore, other embodiments of the exemplary embodiments may have different values.

It should be noted that similar reference numerals and letters indicate similar items in the following drawings, so once an item is defined in one drawing, there is no need to discuss it further in subsequent drawings.

According to an embodiment of the present invention, a cover plate assembly for a lithium ion battery is provided. The cover plate assembly includes a cover plate body 11, a pressure relief portion 12, and a center conductor 13.

The cover plate body 11 has a circular shape, a rectangular shape, an oval shape, and the like. The entire cover body 11 has a sheet shape. The material of the cover body 11 is metal, plastic, or the like. For example, metals include iron-based expanded alloys, stainless steel, kovar alloys, and the like.

The cover body 11 has a through hole in the middle. For example, the through hole is a circular hole, a rectangular hole, an oval hole, or a hole of other shapes.

The through hole extends to form the cylinder 15. For example, the cylinder 15 and the cover body 11 are integrally formed. The barrel 15 protrudes from at least one surface of the cover plate body 11. For example, the cylinder 15 is perpendicular to the cover body 11. This makes the structure of the pressure relief portion 12 more regular.

Of course, in other embodiments, the angle between the cylinder 15 and the cover body 11 is acute or obtuse. In this way, it can also play the role of pressure relief.

The pressure relief portion 12 is located in the cylinder 15 and is sealingly connected with the cylinder 15. The cylindrical body 15 may be a cylindrical body 15 of a through diameter, such as a cylindrical, rectangular parallelepiped, or other prismatic shape; it may also be a cylindrical body 15 of a reduced diameter, such as a prism shape, a circular truncated cone shape, or the like. As long as it can form a sealed connection with the pressure relief portion 12.

The pressure relief portion 12 is configured to generate a crack or fall off from the cover body 11 in response to the deformation of the cover body 11. The pressure relief portion 12 has a ring shape. The pressure relief portion 12 is an insulating material, for example, an inorganic non-metallic material. This material has the characteristics of low toughness, high brittleness, and easy formation of cracks, so that the pressure can be released in time when the internal pressure of the shell body reaches the set value.

For example, when the internal air pressure of the lithium ion battery reaches a set value, the cover body 11 may be significantly deformed. This deformation acts on the pressure relief portion 12 through the cylinder 15. For example, at least a part of the cylinder 15 squeezes the pressure relief portion 12, causing a crack in the pressure relief portion 12, or formed between the pressure relief portion 12 and the cylinder 15 Crevice. Both cracks and crevices can form a gas leakage channel, which allows the internal gas to be released; or the fracture and the gap communicate to form a leakage channel.

For example, when the internal air pressure of the lithium ion battery rises rapidly, at least a part of the pressure relief portion 12 is detached from the cylindrical body 15 due to the internal high pressure, thereby forming a leak passage for rapid pressure relief.

In other embodiments, the deformation of the cover body 11 is not limited to being subjected to air pressure. It may also be that the lithium ion battery is deformed by being pressed by an external force. The deformation causes the pressure relief portion 12 to come off. The energy conversion element inside the damaged lithium ion battery generates gas once in use. The gas will be released from the through hole.

The center conductor 13 is provided in the inner ring of the pressure relief portion 12 and penetrates the pressure relief portion 12 in the axial direction. The material of the center conductor 13 is metal, for example, stainless steel, carbon steel, kovar, or the like.

In this embodiment, since the cover plate body 11, the pressure relief portion 12, and the center conductor 13 are on the same layer, they have a smaller thickness and occupy less space in the height direction. Compared with the multi-layer cover plate assembly, the structure is simple and the assembly is easier.

In addition, the pressure relief portion 12 can play a role of pressure relief, which improves the Safety performance.

In addition, the center conductor 13 has a conduction function, and the cover plate assembly can serve as at least one electrode of the lithium ion battery.

In addition, a better sealing connection can be formed between the cylinder 15 and the pressure relief portion 12. This makes the sealing plate body 11 have a good sealing effect under the condition of a small thickness, and is suitable for small energy storage elements such as needle batteries and button batteries.

In an embodiment, the material of the pressure relief portion 12 is glass or ceramic. During production, the glass or ceramic blank is placed in the through hole. The center conductor 13 is embedded in the blank. Then, the blank is pre-fired to obtain structural strength, and the pressure relief portion 12 forms a sealed connection (ie, sealing) with the through hole and the center conductor 13.

For example, when a glass material is selected, the pressure relief portion 12 is glass-ceramic, borosilicate glass, phosphate glass, or other special glass. The glass can form a solid structure, a hollow structure or a hollow structure, as long as it meets the requirements of pressure relief pressure.

In one embodiment, the cylinder 15 protrudes from one surface of the cover body 11. The cover body 11, the pressure relief portion 12 and the center conductor 13 are flush on the side opposite to the cylinder 15.

It is defined that after assembly into a lithium ion battery, one surface of the cover plate body 11 close to the battery core 19 is the inner surface, and the surface away from the battery core 19 is the outer surface. For example, as shown in FIGS. 1-2, the cylinder 15 protrudes from the outer surface, then the inner surface is flush. In this way, the cylinder 15 does not occupy the space inside the housing.

Or, as shown in FIG. 3, the cylinder 15 protrudes from the inner surface, then the outer surface is flush. This structure makes the shape of the lithium ion battery regular and high space utilization.

In these two protruding ways, a good sealed connection can be formed between the pressure relief portion 12 and the cylinder 15.

In other embodiments, as shown in FIG. 4, the cylinder 15 protrudes toward the inner surface and the outer surface. In this way, the sealing area between the cylinder 15 and the pressure relief portion 12 is larger, and the sealing effect is better, which requires a higher critical pressure value during pressure relief.

In an embodiment, as shown in FIG. 3, the cover plate body 11 and the center conductor 13 each serve as an electrode of the lithium ion battery. For example, the center conductor 13 serves as a positive electrode. The cover body 11 serves as a negative electrode. The pressure relief portion 12 includes an extension portion 21 that covers the end surface of the free end of the cylinder 15.

The free end refers to the end of the cylinder 15 away from the cover plate body 11. When the cylinder 15 protrudes from the outer surface, the extension 21 covers the end surface of the free end. When the central conductor 13 is connected to an external circuit through a wire, the wire will not touch the barrel 15 due to the extension 21, which can effectively prevent the occurrence of a short circuit.

As shown in FIG. 3, when the cylinder 15 protrudes from the inner surface, the extension 21 covers the end surface of the free end. When the center conductor 13 is connected to the battery core 19 through the tabs or wires, the tabs or the wires will not touch the barrel 15 due to the presence of the extension 21, which can effectively prevent the occurrence of a short circuit.

When the cylinder 15 protrudes from the inner surface and the outer surface, the extension 21 covers the end surfaces of the two free ends. It can also effectively prevent short circuits.

In one embodiment, as shown in FIG. 5, the outer edge of the cover body 11 extends to one side to form a ring-shaped connecting portion 23. During assembly, the ring-shaped connecting portion 23 is engaged with the open end of the housing, for example, the ring-shaped connecting portion 23 is located inside or outside the open end. The ring-shaped connecting portion 23 has a larger connecting area, thereby making it easier to connect the cover body 11 and the housing. example For example, laser welding, resistance welding, roll groove and other methods are used for connection.

The part of the cylinder 15 connected to the casing body is defined as the root. When the root is at a right angle, as shown in FIG. 1, stress concentration is easily formed at the root. The deformation of the shell body generates a greater stress at the root, causing plastic deformation at the root. In this way, the deformation of the casing body will not cause the lateral movement of the cylinder body 15, that is, the deformation of the casing body cannot be transmitted to the cylinder body 15, the cylinder body 15 will not squeeze or stretch the pressure relief portion 12, and will not form cracks crack. The explosion-proof components of the lithium ion battery have failed.

In order to solve this technical problem, in one embodiment, as shown in FIG. 2, the cylindrical body 15 forms an outer chamfer R1 outside the root. The outer chamfer R1 can effectively reduce the stress concentration generated at the root, so that the deformation of the casing body can be quickly transmitted to the barrel 15. In this way, the upper half of the cylinder 15 squeezes the pressure relief portion 12 and the lower half stretches the pressure relief portion 12, so that it is easier to form a pressure relief passage.

In addition, the height of the pressure relief portion 12 is difficult to make very small, for example, the height is less than 0.5 mm. Some small lithium-ion batteries require very little pressure relief. This requires that the effective height of the pressure relief portion 12 be 0.2 mm, 0.3 mm, 0.4 mm, or even smaller. However, it is difficult to achieve with existing processing technology.

In one embodiment, as shown in FIG. 2, the cylinder 15 forms an inner chamfer R2 on the inner side of the root. The pressure relief portion 12 fills the area enclosed by the inner chamfer R2. The pressure relief portion 12 includes a straight section b and a curved section. An effective sealed connection is formed between the straight section b and the cylinder 15.

The effective height of the pressure relief portion 12, that is, the size of the straight section b plays a decisive role in the pressure relief pressure. The greater the length of the straight section b, the greater the relief pressure; conversely, the smaller the length of the straight section b, the smaller the relief pressure. The portion of the pressure relief portion 12 (that is, the curved section) located in the area surrounded by the inner chamfer R2 has little effect on the pressure relief pressure. By providing the inner chamfer R2, the sealing area of the straight section b and the cylinder 15 can be effectively reduced, and the effective height of the pressure relief portion 12 can be reduced.

In this way, even if the overall height of the pressure relief portion 12 is 0.5 mm or more, the effective height of the pressure relief portion 12 can reach 0.2 mm, 0.3 mm, 0.4 mm or less because the bending section has little effect on the pressure relief pressure. This makes the explosion-proof components have a lower pressure relief pressure and meets the requirements of small lithium-ion batteries, such as needle batteries or button batteries.

In one embodiment, as shown in FIGS. 6-7, the central conductor 13 protrudes from at least one end surface of the pressure relief portion 12. In this embodiment, when the center conductor 13 is electrically connected to other components, for example, through a wire or FPCB, the wire or FPCB (Flexible Printed Circuit Board, flexible printed circuit board) is not likely to touch the barrel 15.

In addition, when performing laser welding, since the center conductor 13 protrudes from the pressure relief portion 12, the wire or the FPCB is more easily positioned on the center conductor 13, so that the welding position is more accurate.

In one embodiment, as shown in FIG. 7, an insulating layer 16 is provided on the outer surface of the cover plate. The insulating layer 16 covers the upper end surface of the pressure relief portion 12. The upper end surface of the center conductor 13 is exposed.

For example, the insulating layer 16 is a film made of plastic, rubber, silicone, or the like. The film is adhered to the outer surface of the cover plate and the pressure relief portion 12. The center of the film has a hole through which the center conductor 13 is exposed.

Alternatively, the insulating layer 16 is an insulating coating made of insulating material.

In this embodiment, the insulating layer 16 can effectively prevent the wire or FPCB from touching the cover plate body 11 when it is connected to the center conductor 13. In this way, the formation of a short circuit can be effectively prevented.

In addition, the insulating layer can effectively prevent the pressure relief portion 12 from being hit by external objects.

According to another embodiment of the present invention, a lithium ion battery is provided. The shape of the lithium ion battery is cylindrical, rectangular parallelepiped, elliptic cylindrical or other shapes.

The lithium ion battery includes an energy conversion element, a housing, and the above-mentioned cover plate assembly. The energy conversion element is used to perform conversion between chemical energy and electrical energy, for example, a battery cell 19 of a lithium ion battery.

The housing includes a cylindrical portion 24. For example, the cross section of the cylindrical portion 24 is circular, rectangular, oval, or the like. The energy conversion element is located in the cavity enclosed by the cylindrical portion 24.

The cover body 11 covers one end of the cylindrical portion 24. The cover plate body 11 and the center conductor 13 are respectively connected to the two electrodes of the energy conversion element. For example, the cover body 11 and the center conductor 13 serve as the positive and negative electrodes of the lithium ion battery, respectively.

For example, there are two cover plate components. The two cover plate bodies 11 are respectively provided at opposite ends of the cylindrical portion 24.

Alternatively, there may be one cover plate assembly. The end of the cylindrical portion 24 opposite to the cover plate assembly is the bottom 25. The bottom portion 25 and the cylindrical portion 24 are integrally formed.

The lithium ion battery has the characteristics of high safety factor and high energy density.

In one embodiment, the cylinder 15 of the cover plate assembly protrudes into the cavity. The energy conversion element forms a concave structure at a position corresponding to the cylinder 15 and the pressure relief portion 12.

For example, the battery cell 19 of the lithium ion battery has a wound structure. The cell 19 includes a center post 20 and a membrane electrode. The membrane electrode includes a positive electrode material, a negative electrode material, and a separator located between the positive electrode material and the negative electrode material. The membrane electrode is wound on the central post 20. The middle of the winding structure forms a concave structure, that is, the edge forms a drop with the middle. During assembly, the cylinder 15 and the pressure relief portion 12 are located in the recessed structure.

This arrangement makes full use of the space inside the housing, which allows the battery core 19 to store more electrical energy. Lithium ion batteries have higher energy density.

In one embodiment, a gap 14 is formed between the center conductor 13 and the recessed structure. The center conductor 13 is connected to one electrode of the energy conversion element (for example, the positive electrode material of the cell 19) through the tab. The tabs form a retractable structure 22 within the gap 14. The retractable structure 22, that is, the pole ear reserves a set length, so that it can be stretched or shortened according to actual needs, so that the position of the end of the pole ear can be positioned according to actual needs, rather than being fixed. In this way, the accuracy requirements for assembly of other components can be reduced, and the difficulty of assembling lithium-ion batteries can be reduced.

For example, the retractable structure may be, but not limited to, U-shaped, folded-shaped, wave-shaped, and other structures, and those skilled in the art may choose according to actual needs.

According to yet another embodiment of the present invention, a lithium ion battery is provided. As shown in FIG. 5, in this embodiment, the outer edge of the cover body 11 extends to one side to form a ring-shaped connecting portion 23. The cover body 11 covers one end of the cylindrical portion 24. The energy conversion element (for example, the battery core 19) is located in the cylindrical portion 24. The cover plate body 11 and the center conductor 13 are respectively connected to the two electrodes of the energy conversion element.

The outer edge of the cover plate body 11 extends to one side to form a ring-shaped connecting portion 23. The end of the cylindrical portion 24 forms an inwardly closed portion 26. The mouth portion 26 has a structure in which the mouth of the cylindrical portion 24 contracts inward. The ring-shaped connecting portion 23 is sleeved on the outside of the closing portion 26. The ring-shaped connecting portion 23 overlaps the closing portion 26. For example, the cover body 11 and the housing are connected together by laser welding, resistance welding, rolling groove, or the like. The ring-shaped connecting portion 23 facilitates the assembly of the cover body 11 and the housing.

In one embodiment, the dielectric strength of the lithium-ion battery exceeds 1000V. The pressure level of the lithium ion battery seal exceeds the pressure level of the traditional plastic riveted lithium ion battery by at least 3 Magnitude.

Although some specific embodiments of the creation have been described in detail through the embodiments, those skilled in the art should understand that the above embodiments are only for illustration, not for limiting the scope of the creation. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present creation. The scope of this creation is limited by the attached request.

11: Cover body

12: Pressure relief

13: Center conductor

R1: outer chamfer

R2: inner chamfer

b: straight section

Claims (15)

A cover plate assembly for a lithium ion battery includes: a cover plate body, a central portion of the cover plate body has a through hole, the through hole extends to form a cylindrical body, the cylindrical body protrudes from at least one of the cover plate body A pressure relief portion, the pressure relief portion is located in the cylinder body and is in sealed connection with the cylinder body, the pressure relief portion is in a ring shape, the pressure relief portion is configured to generate a crack in response to deformation of the cover plate body or from The cover plate body is detached; and a central conductor is provided in the inner ring of the pressure relief portion and penetrates the pressure relief portion in the axial direction. The cover plate assembly for a lithium ion battery according to claim 1, wherein the pressure relief portion is an inorganic non-metallic material. The cover plate assembly for a lithium ion battery according to claim 2, wherein the material of the pressure relief part is glass or ceramics. The cover plate assembly for a lithium ion battery as described in claim 1, wherein the barrel protrudes from one surface of the cover plate body, the cover plate body, the pressure relief portion, and the center conductor are connected to the barrel The opposite side of the body is flush. The cover plate assembly for a lithium ion battery as described in claim 2, wherein the cover plate body and the center conductor respectively serve as an electrode of the lithium ion battery, and the pressure relief portion includes an end surface covering a free end of the barrel One extension. The cover plate assembly for a lithium ion battery according to any one of claims 1 to 5, wherein the outer edge of the cover plate body extends to one side to form an annular connection portion. The cover plate assembly for a lithium ion battery according to any one of claims 1 to 5, wherein the barrel is perpendicular to the cover plate body. The cover plate assembly for a lithium ion battery as described in any one of claims 1 to 5, wherein the portion of the cylinder body connected to the cover plate body is defined as a portion, and an outer cover is formed outside the root portion angle. The cover plate assembly for a lithium ion battery according to any one of claims 1 to 5, wherein the portion of the cylinder body connected to the cover plate body is defined as a portion, and an inner chamfer is formed inside the root portion , The pressure relief portion fills the area enclosed by the inner chamfer. The cover plate assembly for a lithium ion battery according to any one of claims 1 to 5, wherein the center conductor protrudes from at least one end surface of the pressure relief portion. The cover plate assembly for a lithium ion battery according to any one of claims 1 to 5, wherein an insulating layer is provided on an outer surface of the cover plate, the insulating layer covering an upper end surface of the pressure relief portion, the The upper end face of the center conductor is bare. A lithium ion battery, comprising: an energy conversion element; a casing including a cylindrical portion, the energy conversion element is located in a cavity enclosed by the cylindrical portion; and any of claims 1 to 11 In one of the cover plate assemblies described above, the cover plate body covers one end of the cylindrical portion, and the cover plate body and the center conductor are respectively connected to two electrodes of the energy conversion element. The lithium ion battery according to claim 12, wherein a cylinder of the cover plate assembly protrudes into the cavity, and the energy conversion element forms a concave structure at a portion corresponding to the cylinder and the pressure relief portion. The lithium ion battery according to claim 13, wherein a gap is formed between the center conductor and the recessed structure, the center conductor is connected to an electrode of the energy conversion element through a tab, and the tab is within the gap Form a retractable structure. A lithium ion battery, comprising: an energy conversion element; a housing including a cylindrical portion, the energy conversion element is located in the cylindrical portion; the cover plate assembly according to claim 6, the cover plate body cover Closed to one end of the cylindrical portion, the cover plate body and the center conductor are respectively connected to the two electrodes of the energy conversion element; and the end of the cylindrical portion forms an inwardly-receiving portion, and the annular connecting portion is sleeved On the outside of the closing part.

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