CN219106342U

CN219106342U - Lithium ion battery

Info

Publication number: CN219106342U
Application number: CN202223584120.XU
Authority: CN
Inventors: 章鑫杰; 赵瑞瑞; 彭燕秋; 邱欣斌; 刘金成
Original assignee: Eve Energy Co Ltd
Current assignee: Eve Energy Co Ltd
Priority date: 2022-12-30
Filing date: 2022-12-30
Publication date: 2023-05-30
Anticipated expiration: 2032-12-30

Abstract

The utility model relates to a lithium ion battery, which comprises a shell, a winding core and a top cover assembly, wherein the winding core is arranged in the shell, the top cover assembly is used for sealing an opening end of the shell, the top cover assembly comprises a cover plate, a sleeve, a sealing element and a pole, the cover plate is welded and fixed with the opening end of the shell, the sleeve is arranged on the cover plate in a penetrating manner and is welded and fixed with the cover plate, the pole is arranged on the sleeve in a penetrating manner and is spaced from the sleeve, the sealing element is arranged between the sleeve and the pole, and the pole is electrically connected with the winding core. The cover plate is connected with the shell and the sleeve is connected with the cover plate in a welding mode, so that the cover plate has high connection strength and high connection tightness, and the sealing element is inserted into the sleeve to play a role in fixing and sealing the pole. This structure is favorable to guaranteeing to have sufficient contact surface between sealing member and the sleeve through setting up sealing member and telescopic grafting degree of depth, and then guarantees the connection steadiness and the leakproofness of sealing member to the utmost point post.

Description

Lithium ion battery

Technical Field

The utility model relates to the technical field of batteries, in particular to a lithium ion battery.

Background

As a medical device, an implantable neurostimulator delivers an electrical stimulation signal to a target nerve through a stimulation electrode. The major product types currently include Vagus Nerve Stimulators (VNS), deep brain nerve stimulators (DBS), spinal cord nerve stimulators (SCS), sacral Nerve Stimulators (SNS), and the like. Lithium ion batteries are used as power sources for implantable neurostimulators, and typically have a design life of 10 to 15 years or even longer. The existing lithium ion battery mainly comprises a shell, a winding core and a top cover assembly, wherein the winding core is arranged in the shell, the top cover assembly comprises a cover plate and positive and negative electrode posts arranged on the cover plate, the positive and negative electrode posts are separated from the cover plate through plastic blocks, the plastic blocks play roles in insulation and sealing, and an adhesive layer is formed between the plastic blocks and the cover plate in an injection molding mode to ensure tightness. The prior art has the following defects: because the lithium ion battery constantly vibrates along with the movement of a human body, and the service lives of the plastic block and the adhesive layer are shorter, the plastic block and the adhesive layer can be loosened, and then the lithium ion battery is caused to have the problems of liquid leakage, poor air tightness and the like.

Disclosure of Invention

The utility model aims to provide a lithium ion battery which is good in sealing performance and long in service life.

To achieve the purpose, the utility model adopts the following technical scheme:

the utility model provides a pair of lithium ion battery, including shell, book core and top cap subassembly, roll up the core set up in the shell, top cap subassembly is used for the shutoff the open end of shell, top cap subassembly includes apron, sleeve, sealing member and utmost point post, the apron with the open end welded fastening of shell, the sleeve wear to locate the apron and with apron welded fastening, utmost point post wear to locate the sleeve and with the sleeve interval, the sealing member set up in the sleeve with between the utmost point post, utmost point post with roll up core electric connection.

As a preferred scheme of lithium ion battery, the top cover assembly further comprises an insulating piece, the insulating piece is arranged on one side face, facing the winding core, of the cover plate, and one end of the pole penetrates through the insulating piece and is electrically connected with the winding core.

As a preferable scheme of the lithium ion battery, a first protruding portion is arranged on one side face, facing the cover plate, of the insulating piece, a first groove matched with the first protruding portion is formed in the cover plate, and the first protruding portion is spliced with the first groove.

As a preferred scheme of the lithium ion battery, a second protruding portion is arranged on one side face, facing the winding core, of the insulating piece, and the second protruding portion is used for limiting movement of the winding core towards the cover plate.

As a preferred scheme of the lithium ion battery, a second groove is formed in one side face, facing the cover plate, of the insulating piece, and one end of the sleeve is connected with the second groove in an inserting mode.

As a preferable mode of the lithium ion battery, the circumference of the sleeve is provided with an installation step, and the installation step is abutted to the cover plate or the insulating member.

As a preferable mode of the lithium ion battery, the mounting step is abutted with one side face of the insulating piece, which faces the cover plate.

As a preferred scheme of the lithium ion battery, the top cover assembly further comprises a connecting sheet, the connecting sheet is arranged at one end, close to the winding core, of the pole post, and the pole lug of the winding core is connected with the connecting sheet.

As a preferred scheme of the lithium ion battery, the cover plate is inserted into the shell.

As a preferred scheme of the lithium ion battery, the top cover assembly further comprises a sealing nail, a liquid injection hole for injecting electrolyte is formed in the cover plate, and the sealing nail is used for sealing the liquid injection hole.

As a preferred scheme of the lithium ion battery, the number of the pole posts is two, one pole post penetrates through the sleeve, the other pole post is arranged on the cover plate, and the two pole posts are respectively and electrically connected with the two pole lugs on the winding core.

As a preferable scheme of the lithium ion battery, the material of the pole is any one of a molybdenum rod, a molybdenum alloy rod, a kovar alloy rod, a nickel rod, a gold rod or a copper rod; and/or the number of the groups of groups,

the shell is made of any one of a titanium plate, a titanium alloy plate, an aluminum plate or a stainless steel plate; and/or the number of the groups of groups,

the sealing element is made of glass.

As a preferable scheme of the lithium ion battery, the lithium ion battery further comprises an insulating top film, wherein the top film is arranged at one end of the winding core, which faces to the top cover assembly, and an avoidance hole for penetrating through the tab of the winding core is formed in the top film; and/or the number of the groups of groups,

the winding core is characterized by further comprising an insulating bottom film, wherein the bottom film is arranged at one end of the winding core, which is away from the top cover assembly.

As a preferred scheme of the lithium ion battery, the top film comprises a first film and at least one second film, the first film is abutted to one end of the winding core, which faces the top cover assembly, the second film is vertically arranged at the end part of the first film, and the second film is clamped between the winding core and the shell.

Compared with the prior art, the utility model has the beneficial effects that:

the lithium ion battery provided by the utility model has the advantages that the cover plate is connected with the shell and the sleeve is connected with the cover plate in a welding manner, the connection strength and the connection tightness are high, the lithium ion battery is prevented from loosening due to vibration in a human body, and the lithium ion battery has the characteristics of good tightness and long service life. Meanwhile, a sealing piece is arranged between the sleeve and the pole, and the sealing piece is inserted into the sleeve to fix and seal the pole. This structure is favorable to guaranteeing to have sufficient contact surface between sealing member and the sleeve through setting up sealing member and telescopic grafting degree of depth, and then guarantees the connection steadiness and the leakproofness of sealing member to the utmost point post.

Drawings

Fig. 1 is a schematic view of a lithium ion battery according to an embodiment of the utility model.

Fig. 2 is an exploded view of a lithium ion battery according to an embodiment of the present utility model.

Fig. 3 is a cross-sectional view of a lithium ion battery according to an embodiment of the present utility model.

Fig. 4 is a cross-sectional view of a cap assembly according to an embodiment of the present utility model.

Fig. 5 is a schematic view of a top cap assembly according to an embodiment of the present utility model.

Fig. 6 is a cross-sectional view of a sleeve, seal and post of an embodiment of the present utility model.

Fig. 7 is a cross-sectional view of a cover plate according to an embodiment of the present utility model.

Fig. 8 is a schematic view of a top film according to an embodiment of the present utility model.

In the figure:

1. a housing; 2. a winding core; 21. a tab; 22. an adapter; 3. a top cover assembly; 31. a cover plate; 311. a first groove; 312. a through hole; 313. a liquid injection hole; 32. a sleeve; 321. mounting steps; 33. a seal; 34. a pole; 35. an insulating member; 351. a first boss; 352. a second protruding portion; 353. a second groove; 354. a communication hole; 36. a connecting sheet; 37. sealing nails; 4. a top film; 41. a first membrane; 42. a second membrane; 43. avoidance holes; 5. and (3) a bottom film.

Detailed Description

In order to make the technical problems solved, the technical scheme adopted and the technical effects achieved by the utility model more clear, the technical scheme of the utility model is further described below by a specific embodiment in combination with the attached drawings.

As shown in fig. 1 to 4, the lithium ion battery provided by the utility model comprises a shell 1, a winding core 2 and a top cover assembly 3. The shell 1 is of a cavity structure, the shell 1 is provided with an accommodating cavity with one end open, the winding core 2 is arranged in the accommodating cavity of the shell 1, the top cover assembly 3 is arranged at the open end of the shell 1, and the top cover assembly 3 can seal the open end of the shell 1 so that the accommodating cavity of the shell 1 is in a sealing state. The cap assembly 3 includes a cap plate 31, a sleeve 32, a seal 33, and a post 34. The cover plate 31 is used for blocking the open end of the shell 1, and the cover plate 31 is welded and fixed with the open end of the shell 1. The sleeve 32 is used for installing the pole 34, the sleeve 32 is arranged on the cover plate 31 in a penetrating mode, and the sleeve 32 and the cover plate 31 are fixed in a welding mode. The pole 34 is disposed through the sleeve 32, and the pole 34 is coaxial with and spaced apart from the sleeve 32. The seal 33 is made of an insulating material, and the seal 33 is disposed between the sleeve 32 and the pole 34. The seal 33 serves as a fixing and sealing action for the pole 34. The pole 34 is electrically connected with the winding core 2, the pole 34 plays a role of an external conducting circuit, and one end of the pole 34 extends to the outside of the shell 1, so that the pole 34 can be connected with external electric equipment.

It can be understood that the cover plate 31 is connected with the shell 1 and the sleeve 32 is connected with the cover plate 31 in a welding mode, so that the lithium ion battery has strong connection strength and connection tightness, is prevented from loosening due to vibration in a human body, and has the characteristics of good tightness and long service life. Meanwhile, a sealing member 33 is provided between the sleeve 32 and the pole 34, and the sealing member 33 is inserted inside the sleeve 32 to perform a fixing and sealing function for the pole 34. This structure is favorable to guaranteeing to have sufficient contact surface between sealing member 33 and sleeve 32 through setting up the grafting degree of depth of sealing member 33 and sleeve 32, and then guarantees the connection steadiness and the leakproofness of sealing member 33 to post 34.

Optionally, the cover plate 31 is inserted into the housing 1. The cover plate 31 is dimensioned to fit the dimensions of the open end of the housing 1 so that the cover plate 31 can be inserted into the housing 1 and so that a side of the cover plate 31 facing away from the winding core 2 is flush with the end face of the housing 1. Finally, the intersection of the cover plate 31 and the housing 1 is fixed by laser welding. The cover plate 31 is mounted in a plugging and welding mode, so that the connection strength of the cover plate 31 and the shell 1 can be ensured, and the tightness between the cover plate and the shell is ensured.

Optionally, the top cover assembly 3 further includes an insulating member 35, where the insulating member 35 is a plastic plate, and the insulating member 35 plays an insulating role. The insulating member 35 is disposed on a side of the cover 31 facing the winding core 2, so that the cover 31 and the winding core 2 can be separated by the insulating member 35, and the winding core 2 is prevented from moving toward the cover 31 and contacting the cover 31.

Referring to fig. 4 and 7, a side of the insulator 35 facing the cap plate 31 is provided with a first protrusion 351. Correspondingly, the cover plate 31 is provided with a first groove 311 matched with the first protruding part 351, and the first protruding part 351 is spliced with the first groove 311 so as to realize connection and fixation between the insulating piece 35 and the cover plate 31. To secure the connection therebetween, a plurality of first protrusions 351 may be provided on the insulating member 35. The cover plate 31 and the insulating member 35 are connected and fixed in a plugging manner, so that the processing and the assembly are convenient. Of course, in other embodiments, the first protrusion 351 may be provided on the cover plate 31, and correspondingly, the first groove 311 may be provided on the insulator 35.

The cover plate 31 is further provided with a filling hole 313 for filling an electrolyte. The housing 1 is filled with an electrolyte in its receiving cavity for electrochemical reaction with the winding core 2. After the lithium ion battery is assembled, electrolyte is filled into the accommodating cavity through the electrolyte filling hole 313 on the cover plate 31. The cap assembly 3 further includes a sealing spike 37, the sealing spike 37 for sealing off the liquid filling hole 313. After the injection is completed, the sealing nails 37 are inserted into the injection holes 313 of the cap plate 31 and fixed by laser welding to ensure the sealability of the entire cap assembly 3. Meanwhile, a liquid leakage hole is provided in the insulating member 35 at a position corresponding to the liquid injection hole 313 of the cap plate 31 so that the electrolyte can enter the accommodating chamber of the case 1 through the liquid injection hole 313 and the liquid leakage hole.

The insulating member 35 is provided with a second boss 352 on a side facing the winding core 2, the second boss 352 being for restricting movement of the winding core 2 toward the cover plate 31. It will be appreciated that there is a gap between the winding core 2 and the cap assembly 3 to accommodate sufficient electrolyte. To prevent the winding core 2 from moving toward the top cover assembly 3 under the influence of external force, the second protrusion 352 is used to limit the winding core 2 so as to limit the winding core 2 from moving toward the top cover assembly 3. Specifically, the second protruding portion 352 is located at a middle position of the insulator 35. The second protruding portion 352 is of a cavity structure, a communication hole 354 is formed in the second protruding portion 352, and the inside of the second protruding portion 352 is communicated with the accommodating cavity of the housing 1 through the communication hole 354. The electrolyte in the receiving chamber can enter the inside of the second boss 352 through the communication hole 354 so as to store more electrolyte.

The side of the insulating member 35 facing the cover plate 31 is further provided with a second recess 353, the second recess 353 being adapted to receive the sleeve 32. The cover plate 31 is provided with a through hole 312 for penetrating the sleeve 32, and the through hole 312 is communicated with the second groove 353. One end of the sleeve 32 is inserted into the through hole 312 of the cover plate 31, and the other end is inserted into the second groove 353 of the insulator 35. One end of the pole 34 passes through the bottom of the second recess 353 and extends into the receiving chamber of the housing 1.

Referring to fig. 6, the sleeve 32 has a cylindrical structure, and the sleeve 32 is provided with mounting holes penetrating both ends thereof for mounting the sealing member 33 and the pole 34. The sleeve 32 is provided with a mounting step 321 at the periphery thereof, and the mounting step 321 abuts against the cover plate 31 or the insulator 35. It will be appreciated that since the pole 34 is threaded through the sleeve 32, the two ends of the pole 34 that are located outside the sleeve 32 are different in length. By providing the mounting step 321 on the sleeve 32, a foolproof effect can be achieved to facilitate assembly. Meanwhile, the installation step 321 can also increase the contact surface between the sleeve 32 and the cover plate 31 and the insulator 35, and the tightness of the sleeve 32 is improved. In the present embodiment, the diameter of the notch of the second groove 353 is smaller than the diameter of the through hole 312, so that the mounting step 321 of the sleeve 32 can abut with a partial region of the insulator 35 adjacent to the notch of the second groove 353, i.e., the mounting step 321 abuts with a side face of the insulator 35 toward the cover plate 31. Of course, in other embodiments, a step structure corresponding to the mounting step 321 may be provided in the through hole 312 of the cap plate 31 or in the second groove 353 of the insulator 35, so that the mounting step 321 can be mounted on the step structure.

The sealing element 33 is in a cylindrical structure, and the sealing element 33 is inserted into the mounting hole of the sleeve 32. The pole 34 is penetrated through the sealing element 33, and the sealing element 33 has the fixing and sealing functions on the pole 34. The sealing member 33 is made of a glass material, and the glass material has the characteristics of electrolyte resistance, lithium corrosion resistance, high strength and good sealing performance, and the glass is non-magnetic and is suitable for being installed in a human body and used for a long time. Meanwhile, the sealing member 33 is made of glass, is formed by sintering glass frit in the production process, and is convenient to assemble with the sleeve 32. The glass material comprises glass powder, glass granule and the like.

Optionally, referring to fig. 3 and 4, the top cover assembly 3 further includes a connection piece 36, the connection piece 36 being a conductor, the connection piece 36 being used to conduct an electrical circuit between the pole 34 and the winding core 2. The connecting piece 36 is connected with one end of the pole 34 positioned in the shell 1, and the pole lug 21 on the winding core 2 is welded on the connecting piece 36. The connecting piece 36 is made of stainless steel, low carbon steel, titanium, molybdenum alloy, aluminum, etc. In practical application, the material of the connecting piece 36 can be selected according to the materials of the pole 34 and the pole lug 21, so that good welding performance is provided between the connecting piece 36 and the pole 34 and between the connecting piece 36 and the pole lug 21, and the reliability of the electric path between the pole 34 and the winding core 2 is ensured.

The connecting piece 36 has a square, oval, irregular or round shape, and the connecting piece 36 has a length of 5-10mm, a width of 2-5mm, and a thickness of 0.2-1.0 mm.

Optionally, referring to fig. 3 and 8, the lithium ion battery further includes a top film 4 and a bottom film 5. The top film 4 and the bottom film 5 are both sheet structures made of insulating materials. The top film 4 sets up in the one end towards the top cap subassembly 3 of rolling up the core 2, and top film 4 is used for separating pole piece on the core 2 and top cap subassembly 3, avoids the pole piece on the core 2 to be connected with the conductor on the top cap subassembly 3 and arouses the short circuit. The top film 4 includes a first film 41 and at least one second film 42, the first film 41 is abutted against one end of the winding core 2 facing the top cover assembly 3, the second film 42 is vertically disposed at the end of the first film 41, and the second film 42 is clamped between the winding core 2 and the side wall of the housing 1. By providing the second membrane 42, the winding core 2 can be spaced from the side wall of the housing 1 to avoid short circuits. Meanwhile, by providing the second diaphragm 42, the limit of the winding core 2 in the width direction thereof can be achieved, that is, the winding core 2 is prevented from being moved toward the side wall direction of the housing 1 by receiving an external force. The first diaphragm 41 is provided with a relief hole 43, so that the tab 21 on the winding core 2 can pass through the relief hole 43 and be connected with the connecting sheet 36. The backing film 5 sets up in the one end that the core 2 deviates from top cap subassembly 3, and the backing film 5 is used for separating the pole piece on the core 2 with the bottom of shell 1, avoids the pole piece on the core 2 to be connected with shell 1 and arouses the short circuit.

The top film 4 and/or the bottom film 5 is/are made of one of PP, PFA, PET, PE, PTEF, PVC materials.

Alternatively, as shown with reference to fig. 3 to 5, the number of the poles 34 is two, one of which is a positive pole and the other of which is a negative pole. The sleeve 32 is worn to locate by the positive pole, and the one end of positive pole extends to the outside of shell 1, and the one end that the positive pole is located the outside of shell 1 is used for being connected with outside consumer, and the other end of positive pole passes sleeve 32, sealing member 33, insulating member 35 and is connected with connection piece 36. The tab 21 on the winding core 2 comprises a positive tab and a negative tab, and the positive tab passes through the avoiding hole 43 on the top film 4 to be connected with the connecting sheet 36 so as to realize conduction between the winding core 2 and the positive post.

The pole 34 is of cylindrical configuration with a diameter of between 0.5mm and 3 mm.

Referring to fig. 2 and 3, the negative electrode post is directly welded and fixed on the cover plate 31, and the negative electrode tab on the winding core 2 is connected with the cover plate 31 through the adapter 22, so as to realize conduction between the winding core 2 and the negative electrode post. Of course, in other embodiments, the connection structure of the negative electrode post and the winding core 2 may be the same as the connection structure of the positive electrode post and the winding core 2. In this embodiment, the cathode post bracket is welded on the cover plate 31, which is favorable for simplifying the structure of the top cover assembly 3, improving the space utilization rate of the lithium ion battery, and being more favorable for the miniaturization design of the lithium ion battery.

Optionally, the material of the pole 34 is one or more of molybdenum, molybdenum alloy, kovar alloy, nickel, gold, and copper. The pole 34 may be made of a molybdenum rod, a molybdenum alloy rod, a kovar rod, a nickel rod, a gold rod, or a copper rod. It will be appreciated that the pole 34 needs to have good electrical conductivity. Since the lithium ion battery needs to be mounted in the human body, the pole 34 is also required to have good corrosion resistance and non-magnetic properties. Specifically, in this embodiment, the positive electrode column is made of kovar alloy, molybdenum, or molybdenum alloy, and the negative electrode column is made of nickel, nickel-plated gold, or tin-plated copper-clad steel wire.

Alternatively, the material of the housing 1 is titanium, titanium alloy, aluminum, stainless steel, or the like, i.e., the housing 1 may be made of a titanium plate, titanium alloy plate, aluminum plate, or stainless steel plate. The marks are TA1, TA2 and TC4, when the material is TC4, the material is alpha+beta double-phase alloy, vortex is not easy to form during wireless charging, and the charging efficiency is higher.

Optionally, the length of the lithium ion battery is 20-50mm, the width is 10-40mm, the thickness is 4-8 mm, and the lithium ion battery is square, special-shaped or round. Wherein the special-shaped battery is a battery with other shapes besides a cylindrical shape, a button shape and a rectangular shape.

The beneficial effects of this embodiment are:

all connect through the welded mode between apron 31 and the shell 1, between sleeve 32 and the apron 31, have stronger joint strength and connection leakproofness, avoid this lithium ion battery to loosen because of receiving vibration in the human body, have characteristics that the leakproofness is good, long service life. Meanwhile, a sealing member 33 is provided between the sleeve 32 and the pole 34, and the sealing member 33 is inserted inside the sleeve 32 to perform a fixing and sealing function for the pole 34. This structure is favorable to guaranteeing to have sufficient contact surface between sealing member 33 and sleeve 32 through setting up the grafting degree of depth of sealing member 33 and sleeve 32, and then guarantees the connection steadiness and the leakproofness of sealing member 33 to post 34.

The foregoing is merely exemplary of the present utility model, and those skilled in the art should not be considered as limiting the utility model, since modifications may be made in the specific embodiments and application scope of the utility model in light of the teachings of the present utility model.

Claims

1. The utility model provides a lithium ion battery, its characterized in that, includes shell, book core and top cap subassembly, roll up the core set up in the shell, top cap subassembly is used for the shutoff the open end of shell, top cap subassembly includes apron, sleeve, sealing member and utmost point post, the apron with the open end welded fastening of shell, the sleeve wear to locate the apron and with apron welded fastening, utmost point post wear to locate the sleeve and with the sleeve interval, the sealing member set up in the sleeve with between the utmost point post, utmost point post with roll up core electric connection.

2. The lithium ion battery of claim 1, wherein the top cap assembly further comprises an insulating member disposed on a side of the cover plate facing the winding core, and wherein one end of the pole penetrates through the insulating member and is electrically connected with the winding core.

3. The lithium ion battery of claim 2, wherein a side of the insulating member facing the cover plate is provided with a first protruding portion, the cover plate is provided with a first groove matched with the first protruding portion, and the first protruding portion is spliced with the first groove.

4. The lithium ion battery of claim 2, wherein a side of the insulating member facing the winding core is provided with a second boss for restricting movement of the winding core toward the cover plate.

5. The lithium ion battery according to claim 2, wherein a side surface of the insulating member facing the cover plate is provided with a second groove, and one end of the sleeve is inserted into the second groove.

6. The lithium ion battery according to claim 5, wherein a circumferential portion of the sleeve is provided with a mounting step, the mounting step abutting against the cover plate or the insulator.

7. The lithium ion battery of claim 6, wherein the mounting step abuts a side of the insulator facing the cover plate.

8. The lithium ion battery of claim 1, wherein the top cap assembly further comprises a connecting piece disposed at an end of the post adjacent to the winding core, and the tab of the winding core is connected to the connecting piece.

9. The lithium ion battery of claim 1, wherein the cover plate is plugged into the housing.

10. The lithium ion battery of claim 1, wherein the top cap assembly further comprises a sealing nail, the cover plate is provided with a liquid injection hole for injecting electrolyte, and the sealing nail is used for sealing the liquid injection hole.

11. The lithium ion battery of any of claims 1 to 10, wherein the number of the poles is two, one of the poles is arranged on the sleeve in a penetrating manner, the other pole is arranged on the cover plate, and the two poles are respectively electrically connected with the two lugs on the winding core.

12. The lithium ion battery according to any one of claims 1 to 10, wherein the material of the electrode post is any one of a molybdenum rod, a molybdenum alloy rod, a kovar rod, a nickel rod, a gold rod, or a copper rod; and/or the number of the groups of groups,

the sealing element is made of glass.

13. The lithium ion battery according to any one of claims 1 to 10, further comprising an insulating top film, wherein the top film is arranged at one end of the winding core facing the top cover assembly, and an avoidance hole for penetrating a tab of the winding core is arranged on the top film; and/or the number of the groups of groups,

14. The lithium ion battery of claim 13, wherein the top film comprises a first film and at least one second film, the first film is abutted against one end of the winding core facing the top cover assembly, the second film is vertically arranged at the end of the first film, and the second film is clamped between the winding core and the outer shell.