Lithium ion battery and lithium ion battery processing method

Abstract

The invention provides a lithium ion battery and a lithium ion battery processing method. The lithium ion battery comprises a cylindrical shell, the cylindrical shell comprises a first flat plate, a first arc-shaped plate, a second flat plate and a second arc-shaped plate which are connected end to end so as to form a containing cavity in a surrounding mode, and the first arc-shaped plate and / or the second arc-shaped plate protrude towards the side away from the containing cavity; the top cover is arranged at the first opening end of the cylindrical shell; the bottom cover is arranged at the second opening end of the cylindrical shell; the battery core assembly is arranged in the accommodating cavity; wherein the first flat plate and the second flat plate are arranged in parallel, a distance H1 exists between the first flat plate and the second flat plate, and the maximum distance D1 between the first arc-shaped plate and the second arc-shaped plate meets the relation that H1 is larger than or equal to 2.0 mm; and / or, D1 is greater than 2.0 mm; and / or D1 is greater than H1. The problem that the utilization rate of the internal space of the lithium ion battery in the prior art is low is effectively solved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a lithium-ion battery and a lithium-ion battery processing method. Background Art

[0002] At present, the design of lithium-ion batteries mainly focuses on the development of soft-pack cylindrical, square and hard-shell cylindrical, square lithium-ion batteries. These battery forms have gradually revealed some limitations in the application of wearable products.

[0003] In the prior art, although soft-pack cylindrical and square lithium-ion batteries are widely used in wearable devices due to their lightness, thinness and plasticity, their side sealing and folding processes result in low internal space utilization, affecting the improvement of the battery's energy density. Since the capacity of active materials inside the battery is limited by the space occupied by the folding, the optimal configuration cannot be achieved. Summary of the invention

[0004] The main purpose of the present application is to provide a lithium ion battery and a lithium ion battery processing method to solve the problem of low internal space utilization of lithium ion batteries in related technologies.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a lithium-ion battery is provided, comprising: a cylindrical shell, comprising a first flat plate, a first curved plate, a second flat plate and a second curved plate connected end to end to surround and form a receiving cavity, the first curved plate and / or the second curved plate protruding toward a side away from the receiving cavity; a top cover, arranged on the first open end of the cylindrical shell; a bottom cover, arranged on the second open end of the cylindrical shell; a battery cell assembly, arranged in the receiving cavity; wherein the first flat plate and the second flat plate are arranged parallel to each other, a distance H1 between the first flat plate and the second flat plate, and a maximum distance D1 between the first curved plate and the second curved plate satisfy the relationship: H1≥2.0mm; and / or, D1>2.0mm; and / or, D1>H1.

[0006] Further, the first arc plate and the second arc plate are symmetrically arranged with respect to the center plane S1 of the cylindrical shell; or, the centers of the first arc plate and the second arc plate are concentrically arranged.

[0007] Further, the connection between the first flat plate and the first curved plate is transitionally connected through a first circular arc plate; and / or, the connection between the first flat plate and the second curved plate is transitionally connected through a second circular arc plate; and / or, the connection between the second flat plate and the first curved plate is transitionally connected through a third circular arc plate; and / or, the connection between the second flat plate and the second curved plate is transitionally connected through a fourth circular arc plate.

[0008] Furthermore, the battery cell assembly includes a positive electrode tab, and the top cover includes: a cover plate having a through hole; a pole inserted in the through hole, and a first end of the pole is connected to the positive electrode tab; a pressure ring sleeved outside the second end of the pole to press the pole against the cover plate; a sealing structure, a part of the sealing structure is located between the hole wall of the through hole and the pole, a part of the sealing structure is located between the first end of the pole and the cover plate, and another part of the sealing structure is located between the pressure ring and the cover plate.

[0009] Furthermore, along the direction from the top cover to the cylindrical shell, the through hole includes a first hole segment, a second hole segment and a third hole segment which are connected in sequence, the inner diameter of the first hole segment is larger than the inner diameter of the second hole segment, and the inner diameter of the second hole segment is larger than the inner diameter of the third hole segment; wherein, along the direction from the top cover to the cylindrical shell, the inner diameter of the first hole segment gradually decreases; and / or, the inner diameter of at least part of the second hole segment gradually decreases.

[0010] Furthermore, along the direction from the top cover to the cylindrical shell, the pressure ring includes a first ring body, a second ring body and a third ring body which are connected in sequence, the outer diameter of the first ring body is greater than the outer diameter of the second ring body, and the outer diameter of the second ring body is greater than the outer diameter of the third ring body; the outer circumferential surface of the second ring body is connected to the outer circumferential surface of the third ring body through an annular plane, and the third ring body, at least part of the second ring body and the annular plane are crimped with the sealing structure; wherein, along the direction from the top cover to the cylindrical shell, the outer diameter of the second ring body gradually decreases; and / or, the outer diameter of the third ring body gradually decreases.

[0011] Furthermore, the pole includes: a column, which is inserted into the through hole, and the column includes a first column segment and a second column segment which are connected to each other, and the outer diameter of the first column segment is larger than the outer diameter of the second column segment; a connecting plate, which is connected to the end of the first column segment away from the second column segment, and the connecting plate is connected to the positive electrode ear; wherein the end of the second column segment away from the first column segment has a deformation hole, and the aperture of the deformation hole gradually decreases in the direction from the second column segment to the first column segment, so as to generate deformation under pressure to compress the compression ring and the sealing structure.

[0012] Furthermore, the battery cell assembly includes a negative electrode tab. Along the direction from the bottom cover to the cylindrical shell, the bottom cover includes a first plate body, a second plate body and a third plate body connected in sequence. The connection between the first plate body and the second plate body forms a first step surface, and the connection between the second plate body and the third plate body forms a second step surface; wherein, the first plate body is located outside the cylindrical shell, the second plate body extends into the cylindrical shell and the outer peripheral surface contacts the cavity wall of the accommodating cavity, and the negative electrode tab is connected to the third plate body.

[0013] Furthermore, the battery cell assembly also includes a plurality of electrode sheet groups, each electrode sheet group includes a positive electrode sheet, a separator and a negative electrode sheet connected in sequence; wherein the plurality of electrode sheet groups are stacked or wound in sequence.

[0014] According to another aspect of the present application, a lithium-ion battery processing method is provided, which is applicable to the above-mentioned lithium-ion battery, and the lithium-ion battery processing method comprises: step S1: inserting a pole into a through hole of a cover plate, installing a sealing structure between the pole and the hole wall of the through hole, sleeve a pressure ring on one end of the pole, and press the pole and the pressure ring by riveting to form a top cover; step S2: assembling a cylindrical shell and a bottom cover, and installing a battery cell assembly into a receiving cavity of the cylindrical shell so that the negative pole ear of the battery cell assembly is electrically connected to the bottom cover; step S3: injecting electrolyte into the receiving cavity through a first open end of the cylindrical shell, and after the electrolyte is injected, installing the top cover on the first open end to seal the first open end so that the positive pole ear of the battery cell assembly is electrically connected to the pole of the top cover.

[0015] Using the technical solution of the present application, the lithium-ion battery includes a cylindrical shell, a top cover, a bottom cover and a battery cell assembly. The cylindrical shell includes a first flat plate, a first curved plate, a second flat plate and a second curved plate connected end to end to surround and form a receiving cavity. The first curved plate and / or the second curved plate protrude toward the side away from the receiving cavity. The top cover is arranged on the first open end of the cylindrical shell. The bottom cover is arranged on the second open end of the cylindrical shell; the battery cell assembly is arranged in the receiving cavity. In this way, by arranging the first flat plate and the second flat plate parallel to each other and the first curved plate and / or the second curved plate protruding toward the side away from the receiving cavity, the cylindrical shell forms an elliptical structure, thereby providing a larger receiving cavity space without increasing the overall volume of the battery, thereby increasing the loading amount of the active material, solving the problem of low internal space utilization of lithium-ion batteries in related technologies, and effectively improving the energy density of lithium-ion batteries. At the same time, by limiting the distance H1 between the first flat plate and the second flat plate and the maximum distance D1 between the first curved plate and the second curved plate to satisfy the following relationship: H1≥2.0mm; and / or, D1>2.0mm; and / or, D1>H1, the cylindrical shell can ensure a certain thickness to ensure structural strength and safety while making the lithium-ion battery thinner and more suitable for the lightweight requirements of wearable devices.

[0016] Compared with traditional square or cylindrical batteries, the cylindrical shell of the lithium-ion battery in the present application can better adapt to the irregular space inside the wearable device and improve space utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0018] Figure 1 A cross-sectional view of a first embodiment of a lithium-ion battery according to the present application is shown;

[0019] Figure 2 Shows Figure 1 A cross-sectional view of a cylindrical casing of a lithium-ion battery in FIG.

[0020] Figure 3 Shows Figure 1 A cross-sectional view of a top cover of a lithium-ion battery in FIG.

[0021] Figure 4 Shows Figure 3 A cross-sectional view of a cover plate of a top cover;

[0022] Figure 5 Shows Figure 3 A cross-sectional view of a pole of a top cover in FIG.

[0023] Figure 6 Shows Figure 3 A cross-sectional view of a pressure ring of a top cover;

[0024] Figure 7 Shows Figure 1 A cross-sectional view of a bottom cover of a lithium-ion battery in FIG. 1 ; and

[0025] Figure 8 A cross-sectional view of a cylindrical casing of a second embodiment of a lithium-ion battery according to the present application is shown.

[0026] The above drawings include the following reference numerals:

[0027] 10. cylindrical shell; 11. first flat plate; 12. first curved plate; 13. second flat plate; 14. second curved plate;

[0028] 20. Top cover; 21. Cover plate; 211. Through hole; 2111. First hole section; 2112. Second hole section; 2113. Third hole section; 22. Pole; 221. Column; 2211. First column section; 2212. Second column section; 2213. Deformation hole; 222. Connecting plate; 23. Pressing ring; 231. First ring body; 232. Second ring body; 233. Third ring body; 234. Annular plane; 24. Sealing structure;

[0029] 30. bottom cover; 31. first plate body; 32. second plate body; 33. third plate body; 34. first step surface; 35. second step surface;

[0030] 40. Battery cell assembly; 41. Positive electrode tab; 42. Negative electrode tab; 43. Electrode plate assembly; 431. Positive electrode plate; 432. Diaphragm; 433. Negative electrode plate. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0033] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0034] In order to solve the problem of low internal space utilization of lithium-ion batteries in the related art, the present application provides a lithium-ion battery and a lithium-ion battery processing method.

[0035] Embodiment 1

[0036] like Figures 1 to 7As shown, the lithium-ion battery includes a cylindrical shell 10, a top cover 20, a bottom cover 30 and a battery cell assembly 40. The cylindrical shell 10 includes a first flat plate 11, a first curved plate 12, a second flat plate 13 and a second curved plate 14 connected end to end to surround and form a receiving cavity, and the first curved plate 12 and the second curved plate 14 protrude toward the side away from the receiving cavity. The top cover 20 is arranged on the first open end of the cylindrical shell 10, and the bottom cover 30 is arranged on the second open end of the cylindrical shell 10. The battery cell assembly 40 is arranged in the receiving cavity. The first flat plate 11 and the second flat plate 13 are arranged parallel to each other, and there is a distance H1 between the first flat plate 11 and the second flat plate 13, and the maximum distance D1 between the first curved plate 12 and the second curved plate 14 satisfies the relationship: H1≥2.0mm, D1>2.0mm, D1>H1.

[0037] By applying the technical solution of this embodiment, the first flat plate 11 and the second flat plate 13 are arranged parallel to each other, and the first curved plate 12 and the second curved plate 14 are convex toward the side away from the accommodating cavity, so that the cylindrical shell 10 forms an elliptical structure, thereby providing a larger accommodating cavity space without increasing the overall volume of the battery, thereby increasing the loading amount of the active material, solving the problem of low internal space utilization of lithium-ion batteries in related technologies, and effectively improving the energy density of lithium-ion batteries. At the same time, by limiting the distance H1 between the first flat plate 11 and the second flat plate 13 and the maximum distance D1 between the first curved plate 12 and the second curved plate 14 to satisfy the following relationship: H1 ≥ 2.0 mm, D1 > 2.0 mm, D1 > H1, the cylindrical shell 10 can make the lithium-ion battery thinner while ensuring a certain thickness to ensure structural strength and safety, and more suitable for the thin and light requirements of wearable devices.

[0038] Compared with traditional square or cylindrical batteries, the cylindrical shell of the lithium-ion battery in this embodiment can better adapt to the irregular space inside the wearable device, thereby improving space utilization.

[0039] In other embodiments not shown in the drawings, only the first arc plate protrudes toward the side away from the accommodating cavity, so that the shape of the cylindrical shell can be selected more flexibly to meet different usage requirements and working conditions, and also improve the processing flexibility of the staff.

[0040] In other embodiments not shown in the drawings, there is a distance H1 between the first flat plate and the second flat plate and the relationship is satisfied: H1 ≥ 2.0 mm.

[0041] In other embodiments not shown in the drawings, the maximum distance D1 between the first curved plate and the second curved plate satisfies the relationship: D1>2.0 mm.

[0042] In other embodiments not shown in the drawings, there is a distance H1 between the first flat plate and the second flat plate, and a maximum distance D1 between the first curved plate and the second curved plate satisfies the relationship: D1>H1.

[0043] In other embodiments not shown in the drawings, the first flat plate has a distance H1 therebetween and satisfies the relationship: H1 ≥ 2.0 mm, or the maximum distance D1 between the first curved plate and the second curved plate satisfies the relationship: D1 > 2.0 mm.

[0044] In other embodiments not shown in the drawings, the first flat plate and the second flat plate have a distance H1 and satisfy the relationship: H1 ≥ 2.0 mm, and the maximum distance D1 between the first curved plate and the second curved plate satisfies the relationship: D1 > H1.

[0045] Optionally, the first curved plate 12 and the second curved plate 14 are symmetrically arranged about the center plane S1 of the cylindrical shell 10; or, the centers of the first curved plate 12 and the second curved plate 14 are concentrically arranged. In this way, the above arrangement makes the shape selection of the first curved plate 12 and the second curved plate 14 more flexible to meet different use requirements and working conditions, and also improves the processing flexibility of the staff.

[0046] In this embodiment, the first curved plate 12 and the second curved plate 14 are symmetrically arranged about the center plane S1 of the cylindrical shell 10, thereby ensuring the balanced distribution of the cylindrical shell 10 in space, thereby providing better mechanical stability, and thus helping to reduce structural deformation or damage of the lithium-ion battery caused by external impact or pressure during use.

[0047] In other embodiments not shown in the accompanying drawings, the centers of the first arc plate and the second arc plate are concentrically arranged to ensure the structural consistency of the cylindrical shell in the radial direction, which helps to evenly disperse the internal pressure, reduce stress concentration, and further improve the stability and durability of the battery structure.

[0048] Optionally, the connection between the first flat plate 11 and the first curved plate 12 is transitionally connected through a first arc plate; and / or, the connection between the first flat plate 11 and the second curved plate 14 is transitionally connected through a second arc plate; and / or, the connection between the second flat plate 13 and the first curved plate 12 is transitionally connected through a third arc plate; and / or, the connection between the second flat plate 13 and the second curved plate 14 is transitionally connected through a fourth arc plate. In this way, the above arrangement allows a smooth transition between the connection between the flat plate and the curved plate, which not only avoids the generation of sharp edges or corners that may cut or scratch the user, thus improving the user experience, but also avoids stress concentration at the connection that may affect the structural strength of the cylindrical shell 10.

[0049] In this embodiment, the connection between the first flat plate 11 and the first curved plate 12 is transitionally connected through the first arc plate, the connection between the first flat plate 11 and the second curved plate 14 is transitionally connected through the second arc plate, the connection between the second flat plate 13 and the first curved plate 12 is transitionally connected through the third arc plate, and the connection between the second flat plate 13 and the second curved plate 14 is transitionally connected through the fourth arc plate. In this way, by using arc plate transitional connections at the connection between the first flat plate 11 and the first curved plate 12, the connection between the first flat plate 11 and the second curved plate 14, the connection between the second flat plate 13 and the first curved plate 12, and the connection between the second flat plate 13 and the second curved plate 14, respectively, stress can be effectively dispersed, and stress concentration points can be avoided from being formed at the edge of the cylindrical shell 10, thereby improving the structural strength and compressive resistance of the cylindrical shell 10. At the same time, the arc transitional connection can more evenly distribute the load than the right-angle connection, reduce the local stress of the material, and extend the service life of the lithium-ion battery.

[0050] Specifically, the transition design of the first arc plate, the second arc plate, the third arc plate and the fourth arc plate can make the internal space of the cylindrical shell 10 smoother and more continuous, reduce the ineffective area of ​​the internal space, thereby increasing the loading amount of active materials inside the lithium-ion battery, and further improving the energy density of the lithium-ion battery.

[0051] like Figure 3 As shown, the battery cell assembly 40 includes a positive pole ear 41, and the top cover 20 includes a cover plate 21, a pole 22, a pressure ring 23 and a sealing structure 24. Among them, the cover plate 21 has a through hole 211, the pole 22 is inserted into the through hole 211, and the first end of the pole 22 is connected to the positive pole ear 41. The pressure ring 23 is sleeved outside the second end of the pole 22 to press the pole 22 onto the cover plate 21. A portion of the sealing structure 24 is located between the hole wall of the through hole 211 and the pole 22, a portion of the sealing structure 24 is located between the first end of the pole 22 and the cover plate 21, and another portion of the sealing structure 24 is located between the pressure ring 23 and the cover plate 21. In this way, by inserting the pole 22 into the through hole 211 of the cover plate 21, and then using the pressure ring 23 to press it, and coordinating the setting of the sealing structure 24, the assembly process of the top cover 20 is simplified, the assembly difficulty is reduced, and the production efficiency and the consistency of the finished product are improved. At the same time, the tight connection of the components in the top cover 20 and the optimization of the sealing structure contribute to the improvement of the internal thermal conduction path of the battery, which can more effectively conduct the heat generated by the battery during operation through the top cover assembly, thereby improving the thermal management and heat dissipation performance of the battery, extending the life of the lithium-ion battery and improving safety.

[0052] Specifically, the connection between the pole 22 and the positive pole ear 41, and the pressing effect of the pressure ring 23 on the pole 22, ensure the stability of the electrical connection of the lithium-ion battery during the charging and discharging process. The multi-directional arrangement of the sealing structure 24 (located between the hole wall of the through hole 211 and the pole 22, between the first end of the pole 22 and the cover plate 21, and between the pressure ring 23 and the cover plate 21) forms a multiple sealing layer, which effectively prevents electrolyte leakage and the intrusion of external moisture or impurities, improves the packaging sealing of the lithium-ion battery, and increases the safety and service life of the lithium-ion battery. The pressure ring 23 is sleeved on the second end of the pole 22, and the pole 22 is pressed against the cover plate 21 by means of riveting, which not only enhances the connection strength between the pole 22 and the cover plate 21, but also further improves the structural stability of the top cover 20, which can withstand the internal pressure changes during the charging and discharging process of the lithium-ion battery and maintain the integrity of the top cover 20.

[0053] like Figure 4 As shown, along the direction from the top cover 20 to the cylindrical shell 10, the through hole 211 includes a first hole segment 2111, a second hole segment 2112 and a third hole segment 2113 which are connected in sequence, the inner diameter of the first hole segment 2111 is larger than the inner diameter of the second hole segment 2112, and the inner diameter of the second hole segment 2112 is larger than the inner diameter of the third hole segment 2113. In this way, the design of the stepped hole can better accommodate and fix the sealing structure 24. During the process of inserting and riveting the pole 22, the difference in the apertures of different hole segments can squeeze the sealing structure 24 to form a multi-level seal, effectively avoiding electrolyte leakage, and at the same time enhancing the protection capability of the lithium-ion battery against the external environment, thereby improving the safety and service life of the lithium-ion battery.

[0054] In this embodiment, the gradually decreasing design of the aperture of each hole segment in the through hole 211, combined with the structure of the pole 22 and the pressure ring 23, can increase the structural strength of the top cover 20, thereby allowing the pressure ring 23 to more effectively fix the pole 22 during the riveting process, thereby providing additional support force when the internal pressure of the lithium-ion battery changes.

[0055] Optionally, the inner diameter of the first hole section 2111 gradually decreases in the direction from the top cover 20 to the cylindrical shell 10; and / or, the inner diameter of at least part of the second hole section 2112 gradually decreases. In this way, the gradually decreasing aperture design helps to form a tighter sealing effect. When the pole 22 is inserted into the through hole 211, the gradually decreasing aperture can more effectively squeeze the sealing structure 24, form a multi-stage seal, reduce the risk of electrolyte leakage, enhance the sealing of the lithium-ion battery package and prevent the intrusion of external moisture or impurities, and improve the safety and service life of the lithium-ion battery.

[0056] In this embodiment, along the direction from the top cover 20 to the cylindrical shell 10, the inner diameter of the first hole section 2111 gradually decreases, and the inner diameter of at least a portion of the second hole section 2112 gradually decreases.

[0057] As shown Figure 6 in FIG. 1, along the direction from the top cover 20 to the cylindrical housing 10, the pressing ring 23 includes a first ring body 231, a second ring body 232 and a third ring body 233 which are sequentially connected. The outer diameter of the first ring body 231 is greater than that of the second ring body 232, and the outer diameter of the second ring body 232 is greater than that of the third ring body 233. The outer peripheral surface of the second ring body 232 is connected to the outer peripheral surface of the third ring body 233 through an annular plane 234, and the third ring body 233, at least part of the second ring body 232 and the annular plane 234 are crimped to the sealing structure 24. In this way, the stepped structure design of the pressing ring 23 can increase the contact area with the sealing structure 24 during the crimping process through the change of the outer diameters of different ring bodies, and then more effectively extrude the sealing structure 24 to form multiple seals, significantly enhancing the sealing performance between the top cover 20 and the cylindrical housing 10, and effectively preventing the leakage of the electrolyte and the intrusion of external moisture or impurities.

[0058] Specifically, the above-mentioned ring body design (the first ring body 231, the second ring body 232, the third ring body 233) of the pressing ring 23 and the gradual decrease of its size increase the contact area and the pressing force between it and the terminal post 22 and the cover plate 21, thereby improving the mechanical connection strength and structural stability of the top cover 20, and enabling it to withstand the internal pressure change during the charging and discharging process of the lithium-ion battery and maintain the integrity and reliability of the top cover 20. At the same time, a vertical force can be generated on the annular plane 234, thereby enhancing the pressing effect of the pressing ring 23 and enhancing the overall structural strength of the top cover 20.

[0059] Optionally, along the direction from the top cover 20 to the cylindrical housing 10, the outer diameter of the second ring body 232 gradually decreases; and / or, the outer diameter of the third ring body 233 gradually decreases. In this way, the outer diameters of the second ring body 232 and / or the third ring body 233 gradually decrease, thereby increasing the contact area between it and the sealing structure 24 during the pressing process, and thus forming a tighter seal to ensure the sealing performance between the top cover 20 and the cylindrical housing 10, effectively preventing the leakage of the electrolyte, and improving the stability and safety of the lithium-ion battery.

[0060] In this embodiment, along the direction from the top cover 20 to the cylindrical housing 10, the outer diameter of the second ring body 232 gradually decreases, and the outer diameter of the third ring body 233 gradually decreases.

[0061] As shown Figure 5As shown, the pole 22 includes a column 221 and a connecting plate 222. The column 221 is inserted into the through hole 211, and the column 221 includes a first column segment 2211 and a second column segment 2212 connected to each other, and the outer diameter of the first column segment 2211 is greater than the outer diameter of the second column segment 2212. The connecting plate 222 is connected to the end of the first column segment 2211 away from the second column segment 2212, and the connecting plate 222 is connected to the positive electrode tab 41. Among them, the end of the second column segment 2212 away from the first column segment 2211 has a deformation hole 2213, and the aperture of the deformation hole 2213 gradually decreases in the direction from the second column segment 2212 to the first column segment 2211, so as to generate deformation under pressure to compress the pressing ring 23 and the sealing structure 24. In this way, the electrical connection stability and reliability between the battery cell assembly 40 and the external circuit are ensured by designing two column segments (the first column segment 2211 and the second column segment 2212) of different diameters of the column 221 and firmly connecting the connecting plate 222 to the positive electrode tab 41. At the same time, the above connection method reduces the contact resistance, prevents the electrical connection from loosening, and improves the performance of the lithium-ion battery.

[0062] Specifically, the deformation hole 2213 of the second column segment 2212 is designed so that the pole 22 can be deformed during the riveting or crimping process, thereby pressing the pressure ring 23 and the sealing structure 24. The gradual reduction in the diameter of the deformation hole 2213 helps the pole 22 to form an ideal deformation effect under pressure, enhances the tightness of the sealing structure 24, effectively prevents electrolyte leakage and the intrusion of external moisture or impurities, and improves the sealing performance of the battery package. At the same time, the above-mentioned structural design of the pole 22, especially the setting of the deformation hole 2213 at the end of the second column segment 2212, can maintain the structural integrity and stability of the battery when the battery is subjected to external impact or pressure, thereby improving the mechanical strength and durability of the lithium-ion battery.

[0063] like Figure 7As shown, the battery cell assembly 40 includes a negative electrode tab 42. In the direction from the bottom cover 30 to the cylindrical shell 10, the bottom cover 30 includes a first plate 31, a second plate 32 and a third plate 33 connected in sequence. The connection between the first plate 31 and the second plate 32 forms a first step surface 34, and the connection between the second plate 32 and the third plate 33 forms a second step surface 35. Among them, the first plate 31 is located outside the cylindrical shell 10, the second plate 32 extends into the cylindrical shell 10 and the outer peripheral surface contacts the cavity wall of the accommodating cavity, and the negative electrode tab 42 is connected to the third plate 33. In this way, the multi-level plate design (first plate 31, second plate 32, third plate 33) of the bottom cover 30, especially the formation of the first step surface 34 and the second step surface 35, is conducive to the optimization of the battery packaging structure, so that the bottom cover 30 can fit the accommodating cavity of the cylindrical shell 10 tightly, improve the mechanical stability between components, reduce the waste of internal space of the battery, and thus improve the energy density of the lithium-ion battery.

[0064] Specifically, by directly connecting the negative electrode tab 42 to the third plate 33 of the bottom cover 30, the stability and reliability of the electrical connection are effectively improved, the contact resistance in the connection path is reduced, and efficient electrical transmission between the battery cell assembly 40 and the cylindrical shell 10 is ensured, the energy consumption inside the lithium-ion battery is reduced, and the battery efficiency is improved.

[0065] like Figure 1 As shown, the battery cell assembly 40 also includes a plurality of pole piece groups 43, each pole piece group 43 includes a positive pole piece 431, a separator 432 and a negative pole piece 433 connected in sequence. Among them, the plurality of pole piece groups 43 are stacked or wound in sequence. In this way, on the one hand, the above arrangement makes the structure of the battery cell assembly 40 simpler, easier to process and realize, and reduces the processing cost and difficulty of the battery cell assembly 40; on the other hand, the above arrangement makes the formation method of the battery cell assembly 40 more diverse and flexible to meet different usage requirements and working conditions, and also improves the processing flexibility of the staff. At the same time, through the stacking or winding structure of multiple pole piece groups 43, the space inside the battery cell assembly 40 is effectively utilized, so that the lithium-ion battery can accommodate more active materials, thereby achieving a higher energy density under the same volume.

[0066] Specifically, the positive electrode sheet 431, the separator 432, and the negative electrode sheet 433 are connected in sequence to construct a stable electrochemical reaction path. As an intermediate layer, the separator 432 can not only effectively separate the positive and negative electrode sheets to prevent internal short circuits, but also ensure efficient conduction of ions, thereby improving the charging and discharging efficiency and cycle performance of the lithium-ion battery.

[0067] Optionally, the electrolyte is a liquid electrolyte, a gel electrolyte or a solid electrolyte.

[0068] The present application also provides a lithium ion battery processing method, which is applicable to the above-mentioned lithium ion battery, and the lithium ion battery processing method comprises:

[0069] Step S1: inserting the pole into the through hole of the cover plate, installing the sealing structure between the pole and the hole wall of the through hole, sleeve a pressing ring on one end of the pole, and pressing the pole and the pressing ring by riveting to form a top cover;

[0070] Step S2: Assembling the cylindrical shell and the bottom cover, and placing the battery cell assembly into the accommodating cavity of the cylindrical shell so that the negative electrode tab of the battery cell assembly is electrically connected to the bottom cover;

[0071] Step S3: injecting electrolyte into the accommodating cavity through the first open end of the cylindrical shell. After the electrolyte is injected, installing the top cover on the first open end to seal the first open end so that the positive electrode ear of the battery cell assembly is electrically connected to the pole of the top cover.

[0072] Specifically, by installing the sealing structure between the pole and the through hole, and then using the riveting method to press the pole and the pressure ring, the sealing performance between the top cover and the cylindrical shell is ensured, thereby effectively isolating the external moisture and impurities, preventing the electrolyte from leaking, and improving the safety and stability of the battery. The positive and negative pole ears of the battery cell assembly are electrically connected to the pole and bottom cover of the top cover respectively, ensuring efficient electrical transmission between the battery cell assembly and the battery casing, thereby reducing the contact resistance and improving the charging and discharging efficiency and cycle performance of the lithium-ion battery. At the same time, the above steps provide a simple and efficient battery assembly process. First, assemble the top cover assembly, then install the battery cell assembly into the accommodating cavity of the cylindrical shell, and finally inject the electrolyte and seal the top cover. This sequential and modular assembly method simplifies the production process, improves assembly efficiency and yield, and reduces production costs.

[0073] Embodiment 2

[0074] The lithium ion battery in the second embodiment is different from that in the first embodiment in that the connection method between the flat plate and the curved plate is different.

[0075] like Figure 8 As shown, the first flat plate 11 is directly connected to the first curved plate 12, the first flat plate 11 is directly connected to the second curved plate 14, the second flat plate 13 is directly connected to the first curved plate 12, and the second flat plate 13 is directly connected to the second curved plate 14. In this way, the above connection method makes the connection between the flat plate and the curved plate easier and simpler, and reduces the difficulty of processing.

[0076] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0077] The lithium-ion battery includes a cylindrical shell, a top cover, a bottom cover and a battery cell assembly. The cylindrical shell includes a first flat plate, a first curved plate, a second flat plate and a second curved plate connected end to end to form a receiving cavity. The first curved plate and / or the second curved plate protrude toward the side away from the receiving cavity. The top cover is arranged on the first open end of the cylindrical shell. The bottom cover is arranged on the second open end of the cylindrical shell; the battery cell assembly is arranged in the receiving cavity. In this way, by arranging the first flat plate and the second flat plate parallel to each other and the first curved plate and / or the second curved plate protruding toward the side away from the receiving cavity, the cylindrical shell forms an elliptical structure, thereby providing a larger receiving cavity space without increasing the overall volume of the battery, thereby increasing the loading amount of the active material, solving the problem of low internal space utilization of lithium-ion batteries in related technologies, and effectively improving the energy density of lithium-ion batteries. At the same time, by limiting the distance H1 between the first flat plate and the second flat plate and the maximum distance D1 between the first curved plate and the second curved plate to satisfy the following relationship: H1≥2.0mm; and / or, D1>2.0mm; and / or, D1>H1, the cylindrical shell can ensure a certain thickness to ensure structural strength and safety while making the lithium-ion battery thinner and more suitable for the lightweight requirements of wearable devices.

[0078] Compared with traditional square or cylindrical batteries, the cylindrical shell of the lithium-ion battery in the present application can better adapt to the irregular space inside the wearable device and improve space utilization.

[0079] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0080] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0081] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0082] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A lithium ion battery, characterized in that: include: A cylindrical shell (10) comprises a first flat plate (11), a first curved plate (12), a second flat plate (13) and a second curved plate (14) connected end to end to surround and form a receiving cavity, wherein the first curved plate (12) and / or the second curved plate (14) protrude toward a side away from the receiving cavity; A top cover (20) is arranged on the first opening end of the cylindrical shell (10); A bottom cover (30) is arranged on the second opening end of the cylindrical shell (10); A battery cell assembly (40) is arranged in the accommodating cavity; The first plate (11) and the second plate (13) are arranged parallel to each other, and there is a distance between the first plate (11) and the second plate (13). H1, and the maximum distance D1 between the first curved plate (12) and the second curved plate (14) satisfy the relationship: H1 ≥ 2.0 mm; and / or, D1>2.0mm; and / or, D1>H1.

2. The lithium-ion battery according to claim 1, characterized in that The first arc-shaped plate (12) and the second arc-shaped plate (14) are symmetrically arranged with respect to a center plane S1 of the cylindrical shell (10); or, The centers of the first arc-shaped plate (12) and the second arc-shaped plate (14) are concentrically arranged.

3. The lithium-ion battery according to claim 1, characterized in that The connection between the first flat plate (11) and the first arc plate (12) is transitionally connected via a first arc plate; and / or, The connection between the first flat plate (11) and the second arc-shaped plate (14) is transitionally connected via a second arc plate; and / or, The connection between the second flat plate (13) and the first arc-shaped plate (12) is transitionally connected via a third arc plate; and / or, The connection between the second flat plate (13) and the second arc-shaped plate (14) is transitionally connected via a fourth arc plate.

4. The lithium-ion battery according to claim 1, characterized in that The battery cell assembly (40) comprises a positive electrode tab (41), and the top cover (20) comprises: A cover plate (21) having a through hole (211); A pole (22) is inserted into the through hole (211), and a first end of the pole (22) is connected to the positive electrode tab (41); A pressure ring (23) is sleeved outside the second end of the pole (22) to press the pole (22) onto the cover plate (21); A sealing structure (24), wherein a portion of the sealing structure (24) is located between the hole wall of the through hole (211) and the pole (22), a portion of the sealing structure (24) is located between the first end of the pole (22) and the cover plate (21), and another portion of the sealing structure (24) is located between the pressure ring (23) and the cover plate (21).

5. The lithium-ion battery according to claim 4, characterized in that: Along the direction from the top cover (20) to the cylindrical shell (10), the through hole (211) includes a first hole section (2111), a second hole section (2112) and a third hole section (2114) which are connected in sequence, the inner diameter of the first hole section (2111) is greater than the inner diameter of the second hole section (2112), and the inner diameter of the second hole section (2112) is greater than the inner diameter of the third hole section (2114); wherein, along the direction from the top cover (20) to the cylindrical shell (10), the inner diameter of the first hole section (2111) gradually decreases; and / or, the inner diameter of at least part of the second hole section (2112) gradually decreases.

6. The lithium-ion battery according to claim 4, characterized in that: Along the direction from the top cover (20) to the cylindrical shell (10), the pressure ring (23) includes a first ring body (231), a second ring body (232) and a third ring body (233) which are connected in sequence, the outer diameter of the first ring body (231) is greater than the outer diameter of the second ring body (232), and the outer diameter of the second ring body (232) is greater than the outer diameter of the third ring body (233); the outer peripheral surface of the second ring body (232) is connected to the outer peripheral surface of the third ring body (233) through an annular plane (234), and the third ring body (233), at least part of the second ring body (232) and the annular plane (234) are crimped with the sealing structure (24); wherein, along the direction from the top cover (20) to the cylindrical shell (10), the outer diameter of the second ring body (232) gradually decreases; and / or, the outer diameter of the third ring body (233) gradually decreases.

7. The lithium-ion battery according to claim 4, characterized in that: The pole (22) comprises: A column (221) is inserted into the through hole (211), the column (221) comprising a first column segment (2211) and a second column segment (2212) connected to each other, the outer diameter of the first column segment (2211) being greater than the outer diameter of the second column segment (2212); a connecting plate (222) connected to an end of the first column segment (2211) away from the second column segment (2212), the connecting plate (222) being connected to the positive electrode tab (41); The end of the second column segment (2212) away from the first column segment (2211) has a deformation hole (2213), and the diameter of the deformation hole (2213) gradually decreases in the direction from the second column segment (2212) to the first column segment (2211), so as to deform under pressure to tighten the pressure ring (23) and the sealing structure (24).

8. The lithium-ion battery according to claim 1, characterized in that The battery cell assembly (40) includes a negative electrode tab (42). Along the direction from the bottom cover (30) to the cylindrical shell (10), the bottom cover (30) includes a first plate body (31), a second plate body (32) and a third plate body (33) connected in sequence. A first step surface (34) is formed at the connection between the first plate body (31) and the second plate body (32), and a second step surface (35) is formed at the connection between the second plate body (32) and the third plate body (33); wherein the first plate body (31) is located outside the cylindrical shell (10), the second plate body (32) extends into the cylindrical shell (10) and the outer peripheral surface is in contact with the cavity wall of the accommodating cavity, and the negative electrode tab (42) is connected to the third plate body (33).

9. The lithium-ion battery according to claim 1, characterized in that: The battery cell assembly (40) further comprises a plurality of electrode sheet groups (43), each of the electrode sheet groups (43) comprising a positive electrode sheet (431), a separator (432) and a negative electrode sheet (433) connected in sequence; wherein the plurality of electrode sheet groups (43) are stacked or wound in sequence.

10. A lithium ion battery processing method, characterized in that: Applicable to the lithium ion battery according to any one of claims 1 to 9, the lithium ion battery processing method comprising: Step S1: inserting a pole into a through hole of a cover plate, installing a sealing structure between the pole and a hole wall of the through hole, sleeve a pressing ring on one end of the pole, and pressing the pole and the pressing ring by riveting to form a top cover; Step S2: Assemble the cylindrical shell and the bottom cover, and install the battery cell assembly into the accommodating cavity of the cylindrical shell so that the negative electrode tab of the battery cell assembly is electrically connected to the bottom cover; Step S3: Inject electrolyte into the accommodating cavity through the first opening end of the cylindrical shell. After the electrolyte is injected, install the top cover on the first opening end to seal the first opening end, so that the positive electrode tab of the battery cell assembly is electrically connected to the pole of the top cover.

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