CN221080181U - Secondary battery, battery pack, and electronic device - Google Patents

Abstract

The utility model provides a secondary battery, a battery pack and an electronic device, the secondary battery includes: the electrode assembly comprises a shell, an electrode assembly, a current collecting member, an end cover and a sealing ring, wherein the shell comprises a cylindrical side wall, one end of the side wall comprises an opening, a rolling groove is formed in the side wall, the rolling groove comprises a first groove wall facing the opening side, and a flanging part is formed in the side wall of the opening side; the electrode assembly is accommodated in the shell, the current collecting member is electrically connected with the electrode assembly, the current collecting member comprises a shell connecting part, and the shell connecting part is fixedly connected with the first groove wall; the end cover covers the opening; the sealing ring is partially clamped between the end cover and the flanging part, and is partially clamped between the end cover and the first groove wall; the distance between one side of the flanging part, which is away from the rolling groove, and one side of the first groove wall, which is away from the opening, is the height of the upper end, and the height of the upper end is 2.3-2.5 mm. The utility model can improve the problem that the sealing failure at the position of the rolling groove is easy to cause because of the compression ratio change of the sealing ring between the rolling groove and the joint surface of the sealing ring.

Description

Secondary battery, battery pack, and electronic device

Technical Field

The utility model relates to the technical field of batteries, in particular to a secondary battery, a battery pack and electronic equipment.

Background

The large cylindrical battery (4680 series) is sealed in two ways, one is a mechanical seal and the other is a laser seal. Among them, mechanical sealing is widely used because of its high productivity and low investment cost. At present, when the cylindrical battery is mechanically sealed, a rolling groove is generally formed in the opening position of the shell, a current collecting component is lapped on the rolling groove, a sealing ring and an end cover are installed at the opening, and the opening is sealed through mechanical pier sealing. When adopting this kind of mode to seal, can overlap joint in the laminating face of indent and sealing washer partial region have the mass flow component, and the existence of mass flow component can make there is the difference in height on the laminating face of indent and sealing washer, and the existence of this difference in height can cause the change of sealing washer compressibility to lead to the problem that appears sealed inefficacy between sealing washer and the indent easily.

Disclosure of utility model

In view of the above drawbacks of the prior art, the present utility model provides a secondary battery, a battery pack, and an electronic device, so as to improve the problem of seal failure at the position of the rolling groove due to the change of the compression ratio of the sealing ring between the rolling groove and the sealing ring joint surface.

To achieve the above and other related objects, the present utility model provides a secondary battery comprising: the electrode assembly comprises a shell, an electrode assembly, a current collecting member, an end cover and a sealing ring, wherein the shell comprises a cylindrical side wall, one end of the side wall comprises an opening, a rolling groove recessed towards the inside of the shell is formed in the position, close to the opening, of the side wall, the rolling groove comprises a first groove wall facing the opening side, and the side wall of the opening side extends towards the center of the opening to form a flanging part; the electrode assembly is accommodated in the case, and the rolling groove restricts movement of the electrode assembly in the case in the height direction of the secondary battery; the current collecting component is arranged in the shell and is electrically connected with the electrode assembly, and the current collecting component comprises a shell connecting part which is fixedly connected with the first groove wall; the end cover is arranged between the flanging part and the first groove wall and covers the opening; the sealing ring is at least partially clamped between the end cover and the flanging part, and at least one other part is clamped between the end cover and the first groove wall; the distance between one side of the flanging part, which is away from the rolling groove, and one side of the first groove wall, which is away from the opening, is the upper end height, and the size of the upper end height is 2.3-2.5 mm.

In an example of the secondary battery of the present utility model, the minimum thickness of the sealing ring in the region between the case connecting portion and the end cap in the height direction of the secondary battery is t1, the thickness of the sealing ring beyond the free end of the rolling groove is t3, and the range of (t 3-t 1)/t 3 is 67 to 73%.

In an example of the secondary battery of the present utility model, the minimum thickness of the gasket in the region between the cap and the burring is t2 in the height direction of the secondary battery, and the range of (t 3-t 2)/t 3 is 23 to 37%.

In one example of the secondary battery of the present utility model, the thickness of the case connection part is 0.05 to 0.25mm.

In one example of the secondary battery of the present utility model, the sealing ring has an initial thickness of 0.5 to 1.0mm.

In one example of the secondary battery of the present utility model, the thickness of the end cap is 0.45 to 0.8mm.

In an example of the secondary battery of the present utility model, the outer edge of the end cap exceeds the outer edge of the case connecting part by at least 0.1mm in the radial direction of the secondary battery.

In one example of the secondary battery of the present utility model, the thickness of the case is 0.3 to 0.6mm.

The utility model also provides a battery pack which comprises any secondary battery.

The utility model further provides electronic equipment, which comprises the battery pack.

According to the secondary battery, the distance between one side of the flanging part, which is away from the rolling groove, and one side of the first groove wall, which is away from the opening, is limited, namely, the high dimension of the upper end is limited to be 2.3-2.5 mm, so that the compression rate of the sealing ring between the connecting part of the shell and the end cover can be controlled, and the compression rate of the sealing ring can meet the sealing requirement at the position of the rolling groove, and the problem that the sealing of the sealing ring at the position of the rolling groove is easy to lose efficacy can be solved. The high-end size of the upper end is controlled to control the compression rate of the sealing ring, so that on one hand, the high-end size of the upper end is convenient to measure after sealing is finished, whether the sealing of the sealing ring at the rolling groove position is qualified or not can be judged by measuring the high-end size of the upper end, and secondary batteries with unqualified sealing can be screened in advance, so that the subsequent testing pressure on the sealing performance of the secondary batteries can be reduced; on the other hand, the dimension control of the upper end height can be determined by the process parameters of the pier seal during sealing, so that the dimension adjustment of the upper end height can be realized by setting the process parameters of the pier seal, and the dimension of the upper end height is convenient to adjust and easy to control.

Drawings

In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings that are necessary for the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the utility model and that other embodiments may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a three-dimensional overall schematic view of an embodiment of a secondary battery of the present utility model;

FIG. 2 is a partial cross-sectional view taken along the direction A-A in FIG. 1;

fig. 3 is a schematic view showing a mounting structure of an electrode assembly in a case in an embodiment of a secondary battery according to the present utility model;

FIG. 4 is an enlarged view of a portion of region B of FIG. 2;

fig. 5 is a schematic view of an upper end H of a secondary battery according to an embodiment of the present utility model;

fig. 6 is a schematic view illustrating an installation position between a case connection part and a first groove wall in an embodiment of the secondary battery according to the present utility model;

FIG. 7 is an enlarged view of a portion of region D of FIG. 6;

Fig. 8 is a side view illustrating the structure of a current collecting member in an embodiment of a secondary battery according to the present utility model;

fig. 9 is a top view of a current collecting member in an embodiment of a secondary battery according to the present utility model;

FIG. 10 is a schematic view showing the thickness of the sealing ring at different positions after the sealing in accordance with one embodiment of the present utility model;

FIG. 11 is a schematic view showing the overall structure of an embodiment of a battery pack according to the present utility model;

fig. 12 is a schematic view showing a structure in which the battery pack of the present utility model is mounted on a vehicle.

Description of element reference numerals

100. A secondary battery; 110. a housing; 111. a sidewall; 112. an opening; 113. rolling grooves; 1131. a first groove wall; 11311. a first zone; 11312. a second zone; 114. a burring part; 115. an end wall; 116. a connection part; 117. a first groove; 120. an electrode assembly; 121. a first tab; 130. a current collecting member; 131. a housing connection portion; 132. a body portion; 133. a tab connection part; 134. a connecting arm; 135. a limit part; 140. an end cap; 150. a seal ring; 151. a second groove; 152. a first sealing part; 153. a second sealing part; 154. a third sealing part; 200. a battery pack; 210. a case; 211. a first box portion; 212. a second box portion; 300. an electronic device; 310. a working part.

Detailed Description

Other advantages and effects of the present utility model will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present utility model with reference to specific examples. The utility model may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present utility model. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict. It is also to be understood that the terminology used in the examples of the utility model is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the utility model. The test methods in the following examples, in which specific conditions are not noted, are generally conducted under conventional conditions or under conditions recommended by the respective manufacturers.

Where numerical ranges are provided in the examples, it is understood that unless otherwise stated herein, both endpoints of each numerical range and any number between the two endpoints are significant both in the numerical range. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs and to which this utility model belongs, and any method, apparatus, or material of the prior art similar or equivalent to the methods, apparatus, or materials described in the examples of this utility model may be used to practice the utility model.

It should be understood that the terms such as "upper," "lower," "left," "right," "middle," and "a" and the like are used in this specification for descriptive purposes only and not for purposes of limitation, and that the utility model may be practiced without materially departing from the novel teachings and without departing from the scope of the utility model.

Referring to fig. 1 to 12, the present utility model provides a secondary battery 100, a battery pack 200 and an electronic device 300, wherein the secondary battery 100 can control the compression rate of the sealing ring 150 between the housing connection portion 131 and the end cap 140 by limiting the distance between the side of the flange portion 114 facing away from the rolling groove 113 and the side of the first groove wall 1131 facing away from the opening 112, i.e. the upper end height dimension, and limiting the upper end height dimension to 2.3-2.5 mm, so that the compression rate of the sealing ring 150 meets the sealing requirement at the position of the rolling groove 113, thereby improving the problem that the sealing of the sealing ring 150 at the position of the rolling groove 113 is easy to fail.

Referring to fig. 1 and 2, the structure of the secondary battery 100 will be further described, the secondary battery 100 including: the electrode assembly includes a case 110, an electrode assembly 120, a current collecting member 130, an end cap 140, and a sealing ring 150. The case 110 has a receiving chamber formed therein for receiving the electrode assembly 120, an electrolyte (not shown), and other components, and the case 110 may have an opening 112 at one end or may have openings 112 at both ends. The housing 110 may be of various shapes, such as a cylindrical shape, a prismatic shape, etc. The specific dimensions of the case 110 may be determined according to the specific dimensions of the electrode assembly 120, for example, specifications of 46mm in diameter, 80mm in height, 95mm, 120mm, etc. The material of the housing 110 may be various, such as copper, iron, aluminum, steel, aluminum alloy, etc., and in order to prevent the housing 110 from rusting during long-term use, a layer of rust-preventing material, such as metallic nickel, etc., may be plated on the surface of the housing 110.

Referring to fig. 2 to 4, in an example of the secondary battery 100 of the present utility model, the case 110 has a cylindrical structure, the case 110 includes an end wall 115 and a side wall 111 surrounding the end wall 115, the end wall 115 is a closed end, and the opening 112 opposite to the end wall 115 is an open end. The side wall 111 is formed with a rolling groove 113 near the opening 112, and the rolling groove 113 is recessed toward the inside of the housing 110; the side of the rolling groove 113 facing the opening 112 is provided with a first groove wall 1131; the side wall 111 is further provided with a flange portion 114 extending toward the center of the opening 112 at a position close to the opening 112, a connecting portion 116 is further provided between the flange portion 114 and the rolling groove 113, one end of the connecting portion 116 is connected with one end of the flange portion 114 away from the center of the opening 112 in the height direction of the secondary battery 100, the other end of the connecting portion 116 is connected with one end of the first groove wall 1131 away from the center of the opening 112, and a first groove 117 is defined among the first groove wall 1131, the connecting portion 116 and the flange portion 114. The specific dimensions of the rolling groove 113, the burring 114, and the connecting portion 116 are determined according to the dimensions of the secondary battery 100, and in this embodiment, are not particularly limited.

As shown in fig. 2 and 3, the electrode assembly 120 is accommodated in the case 110. The electrode assembly 120 is a component in the cell where electrochemical reactions occur. The case 110 may contain one or more electrode assemblies 120 therein. The electrode assembly 120 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is generally provided between the positive electrode sheet and the negative electrode sheet. The positive electrode plate comprises a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode current collector; the positive electrode current collector comprises a positive electrode coating area and a positive electrode lug connected to the positive electrode coating area, wherein the positive electrode coating area is coated with a positive electrode active material layer, and the positive electrode lug is not coated with the positive electrode active material layer. The negative electrode plate comprises a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode current collector; the negative electrode current collector comprises a negative electrode coating area and a negative electrode tab connected to the negative electrode coating area, wherein the negative electrode coating area is coated with a negative electrode active material layer, and the negative electrode tab is not coated with the negative electrode active material layer. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate or the like. The material of the anode current collector may be copper, the anode active material layer includes an anode active material, and the anode active material may be carbon or silicon, or the like. The separator may be made of PP (polypropylene) or PE (polyethylene). In order to protect and insulate the battery cell, the battery cell can be coated with an insulating film, and the insulating film can be synthesized by PP, PE, PET, PVC or other high polymer materials.

Referring to fig. 2 and 3, in an example of the secondary battery 100 of the present utility model, the electrode assembly 120 is hermetically mounted in the case 110, the electrode assembly 120 is disposed between the end wall 115 and the rolling groove 113 in the height direction of the secondary battery 100, and the rolling groove 113 can restrict the axial movement of the electrode assembly 120 between the end wall 115 and the rolling groove 113. The electrode assembly 120 is provided with a first tab 121 and a second tab at two ends in a length direction, and polarities of the first tab 121 and the second tab are opposite, wherein the first tab 121 faces the opening 112 side, and the first tab 121 is a negative tab. In other embodiments, the first tab 121 may be a positive tab, and the second tab may be a negative tab.

Referring to fig. 2, 4, 6, 7, 8 and 9, the current collecting member 130 includes a body portion 132, a housing connecting portion 131 and a tab connecting portion 133, the tab connecting portion 133 is disposed near a central region of the body portion 132, the housing connecting portion 131 is disposed around an outer periphery of the tab connecting portion 133, the housing connecting portion 131 is electrically connected to the tab connecting portion 133, and the electrical connection manner may be selected from various manners, for example, may be welding connection or may be any manner capable of achieving electrical connection between the housing connecting portion 131 and the tab connecting portion 133, such as integrally formed connection; the number and specific structural forms of the case connection parts 131 and the tab connection parts 133 are not limited as long as a stable electrical connection relationship can be formed between the case 110 and the first tab 121. In this embodiment, in order to improve the assembly efficiency, the housing connection portion 131 and the tab connection portion 133 are integrally connected by press forming, and the housing connection portion 131 is provided with a plurality of housing connection portions 131 arranged in a circular array on the outer periphery of the tab connection portion 133. The tab connection part 133 is welded to the first tab 121 to achieve electrical connection between the current collecting member 130 and the electrode assembly 120; the case connecting part 131 is overlapped on the surface of the first groove wall 1131 in the radial direction along the height direction of the secondary battery 100 to achieve electrical connection between the case connecting part 131 and the case 110; in order to ensure the stability of the electrical connection between the housing connection part 131 and the housing 110, in the present embodiment, the housing connection part 131 is welded to the surface of the first groove wall 1131. In other embodiments, the housing connecting portion 131 and the first groove wall 1131 may not be welded and only abut against each other, and the housing connecting portion 131 may be adhered to the surface of the first groove wall 1131 by conductive adhesive.

Referring to fig. 4, 5, 6 and 7, the sealing ring 150 is installed in the first groove 117, the sealing ring 150 has a second groove 151 with an opening 112 facing the axial direction of the secondary battery 100, and the outer periphery of the end cap 140 is clamped in the second groove 151, so that the sealing ring 150 wraps the outer periphery of the end cap 140 to realize the sealing connection between the end cap 140 and the housing 110. The seal ring 150 includes a first seal portion 152, a second seal portion 153, and a third seal portion 154, the first seal portion 152 is sandwiched between the end cover 140 and the first groove wall 1131, the second seal portion 153 is sandwiched between the flange portion 114 and the end cover 140, the third seal portion 154 is sandwiched between the connection portion 116 and the side wall 111 of the end cover 140, and both ends of the third seal portion 154 are respectively connected to the first seal portion 152 and the second seal portion 153. The first groove wall 1131 includes a first region 11311 and a second region 11312, the first region 11311 is covered with the case connecting part 131, the second region 11312 is not covered with the case connecting part 131, and a height difference is formed on the first groove wall 1131; the specific size of the height difference is determined by the thickness of the housing connection part 131; at least a portion of the second sealing portion 153 is sandwiched between the first region 11311 and the end cap 140, and at least another portion of the second sealing portion 153 is sandwiched between the second region 11312 and the end cap 140, and because the first region 11311 is covered with the housing connecting portion 131, the thickness of the sealing ring 150 located in the first region 11311 is smaller than the thickness of the sealing ring 150 located in the second region 11312, and thus the compression rate of the sealing ring 150 in the first region 11311 is greater than the compression rate of the second region 11312.

Sealing of the sealing ring 150 at the location of the rolling groove 113 is achieved when the compression rate of the first region 11311 is able to complete filling the gap created by the height difference on the first groove wall 1131. The compressibility of the seal 150 in the first region 11311 thus directly affects the sealing effect of the seal 150 at the location of the groove 113. In the height direction of the secondary battery 100, the distance between the side of the burring 114 facing away from the rolling groove 113 and the side of the first groove wall 1131 facing away from the opening 112 is an upper end height H (as shown in fig. 5), and the dimension of the upper end height H is any value in the range of 2.3 to 2.5mm, for example, may be 2.3mm, 2.4mm, 2.5mm, or the like. As can be seen from fig. 4 and 5, the smaller the upper end height H size, the greater the compression rate of the sealing ring 150 located in the first region 11311, the better the sealing effect, and the more positive the sealing effect, the smaller the compression rate of the sealing ring 150 located in the first region 11311, and the worse the sealing effect, as the dimensions of the first groove 117 in the height direction of the secondary battery 100 are restricted. For this reason, in the present embodiment, by limiting the size of the upper end height H to between 2.3 and 2.5mm, the compression rate generated on the sealing ring 150 located in the first region 11311 can fill the sealing gap generated by the height difference on the first groove wall 1131, and the probability of sealing failure caused by the change of the compression rate of the sealing ring 150 between the rolling groove 113 and the bonding surface of the sealing ring 150 is reduced, thereby satisfying the sealing requirement of the secondary battery 100.

To further verify the sealing performance of the secondary battery 100 in the case where the size of the upper end height H of the secondary battery 100 is set between 2.3 and 2.5mm, referring to table 1, table 1 is the sealing performance test results of the secondary batteries 100 corresponding to different upper end heights H under the same conditions of the thickness of the case 110, the thickness of the sealing ring 150, and the thickness of the cap 140 at an internal pressure of 0.8MPa, respectively, the sealing performance test includes two conditions: the first is storage under 130 ℃ heating conditions at different times, and the second is storage under 0.8mpa+60 ℃ conditions at different times; the test thickness of the upper end height H is respectively as follows: 2.2mm, 2.3mm, 2.4mm, 2.5mm and 2.6mm. As can be seen from the test results in table 1, when the upper end height H is 2.2mm, under the corresponding first working condition, two groups of the secondary batteries 100 tested in three groups are not up to standard at 336H, and all three groups are not up to standard at 504H; under the corresponding second working condition, the secondary battery 100 has a group of substandard products at 336h and 504 h; when the upper end height H is 2.3mm, 2.4mm and 2.5mm, under the corresponding first working condition and second working condition, all the secondary batteries 100 tested in the three groups reach the standard in all the test time periods; at an upper end height H of 2.6mm, under the corresponding first working condition, there are one group of secondary batteries 100 which do not reach the standard at 504H. Therefore, it can be seen that the sealing performance of the secondary battery 100 is optimal when the upper end height H is 2.3mm, 2.4mm, 2.5 mm. Therefore, it can be inferred from the test results in the above table that, in the present embodiment, setting the upper end height H between 2.3 and 2.5mm can effectively improve the sealing performance of the secondary battery 100.

TABLE 1

In the application, the sealing performance of the sealing ring 150 at the position of the rolling groove 113 is improved by adopting a mode of controlling the high size of the upper end to realize the control of the compression rate of the sealing ring 150, on one hand, because the high size of the upper end is convenient to measure after the sealing is finished, whether the sealing of the sealing ring 150 at the position of the rolling groove 113 is qualified can be judged by measuring the high size of the upper end, and the secondary battery 100 with unqualified sealing can be screened in advance, so that the subsequent testing pressure on the sealing performance of the secondary battery 100 can be lightened; on the other hand, the dimension control of the upper end height can be determined by the process parameters of the pier seal during sealing, so that the dimension adjustment of the upper end height can be realized by setting the process parameters of the pier seal, and the dimension of the upper end height is convenient to adjust and easy to control.

Since the compression ratio of the sealing ring 150 between the case connecting part 131 and the end cap 140 (i.e., the compression ratio of the sealing ring 150 between the end cap and the first region 11311) directly affects the sealing effect of the sealing ring 150 at the position of the rolling groove 113, preferably, referring to fig. 6 and 10, in an example of the secondary battery 100 of the present utility model, in the height direction of the secondary battery 100, the minimum thickness of the portion of the sealing ring 150 located between the end cap 140 and the first region 11311 is t1, t1 being the distance between the end of the case connecting part 131 (excluding the rounded corner) and the end cap 140 in the height direction of the secondary battery 100; the sealing ring 150 located between the rolling groove 113 and the end cap 140 is free end extending toward the axial side of the secondary battery 100 in the radial direction of the secondary battery 100 and beyond the rolling groove 113, and the thickness of the free end is t3 (the thickness t3 of the sealing ring also varies during the sealing process, but the thickness t3 is close to the initial thickness of the sealing ring in the compression region, so in the present utility model, the compression ratio of the sealing ring is calculated according to the thickness t 3), the compression ratio c1= (t 3-t 1)/t 3 of the sealing ring 150 located between the end cap 140 and the first region 11311, and the compression ratio C1 may be any value ranging from 67 to 73%, for example, 67%, 70%, 73% or the like. The compression rate C1 is set within the range of 67 to 73%, and at this time, the compression rate generated by the seal ring 150 can just fill the sealing gap generated by the height difference on the first groove wall 1131, thereby ensuring the sealing effect at the position of the rolling groove 113. Further, as can be seen from the data in table 1, at the upper end height H in the range of 2.3mm, 2.4mm or 2.5mm, the corresponding compression ratios C1 are 72.75%, 73.75% and 67.50%, respectively. Therefore, the test data in table 1 can verify that the sealing performance of the corresponding secondary battery 100 is better at the compression ratio C1 of 67 to 73%.

It should be noted that, after the compression ratio of the seal ring 150 located between the end cover 140 and the first region 11311 is determined, the compression ratio C2 of the seal ring 150 located between the end cover 140 and the second region 11312 will also be correspondingly determined, and in this embodiment, when the compression ratio C1 of the seal ring 150 located between the end cover 140 and the first region 11311 is 67-73%, the compression ratio C2 of the seal ring 150 located between the end cover 140 and the second region 11312 may be any value in the range of 45-56%, for example, 45%, 50%, 56% and the like.

When the end cover 140 is sealed, the compression rate C3 of the seal ring 150 located in the region between the end cover 140 and the burring 114 directly affects the sealing performance between the burring 114 and the end cover 140, and the compression rate C3 also corresponds to the compression rate C1 of the seal ring 150 below the end cover 140. Referring to fig. 6 and 10, in an example of the secondary battery 100 of the present utility model, the minimum thickness of the second sealing ring portion 153 in the region between the cap 140 and the burring 114 is t2, t2 being the distance between the tip of the burring 114 (excluding the rounded corners) and the cap 140 in the height direction of the secondary battery 100, in the height direction of the secondary battery 100; the compression ratio c3= (t 3-t 2)/t 3 is any value in the range of 23 to 37%, and the compression ratio C3 may be, for example, 23%, 30%, 37%, or the like. Setting the compression ratio C3 in the range of 23 to 37% can achieve a better sealing effect between the end cover 140 and the burring 114 at this time, further reducing the probability of seal failure of the end cover 140. Further, as can be seen from the data in table 1, at the upper end height H of 2.3mm, 2.4mm or 2.5mm, the corresponding compression ratios C3 were 36.86%, 28.37% and 23.6%, respectively. Therefore, the test data in table 1 can verify that the sealing performance of the corresponding secondary battery 100 is better at the compression rate C3 of 23 to 37%. It should be noted that, referring to fig. 10, the method for measuring the upper end H in the present utility model is as follows: a point is taken at each of the planar region of the burring 114 and the planar region of the first groove wall 1131 of the rolling groove 113, and the difference in height between the two in the height direction of the secondary battery 100, which is the dimension of the upper end height H, is measured. When the thickness of the case connecting part 131 is less than 0.05mm, since strength and rigidity are small, deformation is easily caused during processing and transportation, affecting the dimensional accuracy of the case connecting part 131; when the thickness of the housing connection portion 131 is greater than 0.25mm, the height difference generated on the first groove wall 1131 is greater, so that the compression ratio difference between the compression ratio C1 generated in the first region 11311 and the compression ratio C2 generated in the second region 11312 of the sealing ring 150 is too large, the sealing ring 150 is easily cut off, and the probability of seal failure occurs in the use process. Preferably, in the present embodiment, the thickness of the housing connection portion 131 is any value in the range of 0.05 to 0.25mm, for example, 0.05mm, 0.15mm, 0.25mm, or the like. In the present embodiment, the thickness of the case connecting part 131 is 0.15mm. The thickness of the housing connection part 131 is set within the range of 0.05-0.25 mm, so that the housing connection part 131 can be ensured to have certain strength and rigidity, the requirements of processing and transportation are met, the probability that the sealing ring 150 is easily cut off at the connection position of the first region 11311 and the second region 11312 can be reduced, and the stability of the sealing performance in the working process of the secondary battery 100 is improved.

The overall initial thickness of the seal ring 150 may be completely uniform, that is, the initial thicknesses of the first seal portion 152, the second seal portion 153, and the second seal portion 153 may be equal or may be different, and is not particularly limited, and in this embodiment, the initial thicknesses of the first seal portion 152, the second seal portion 153, and the third seal portion 154 may be equal for convenience of molding. The greater the initial thickness of the seal 150, the greater the compressive force that can be tolerated, the less likely it will be crushed during use, but the correspondingly greater the height space that can be occupied, whereas the lesser the compressive force that can be tolerated, the more likely it will be crushed during use, but the less height space that can be occupied. When the initial thickness of the sealing ring 150 is smaller than 0.5mm, at this time, the sealing ring 150 is easy to generate overvoltage and break in the upsetting process, so that the sealing is invalid; when the initial thickness of the sealing ring 150 is greater than 1.0mm, the efficiency of the secondary battery 100 in terms of the height space is greatly affected, which is disadvantageous in terms of the increase in the volumetric energy density of the secondary battery 100. Preferably, in an embodiment of the secondary battery 100 according to the present utility model, the initial thickness of the sealing ring 150 is any value ranging from 0.5 to 1.0mm, for example, 0.5mm, 0.75mm, 1.0mm, or the like. In this embodiment, the initial thickness of the seal 150 is 0.85mm. By setting the initial thickness of the sealing ring 150 within the range of 0.5 to 1.0mm, the probability of sealing failure caused by breakage of the sealing ring 150 due to overpressure can be reduced, and the sealing effect of the secondary battery 100 can be improved; in addition, the influence on the height direction of the secondary battery 100 can be reduced, thereby reducing the influence on the space utilization of the secondary battery 100.

When the thickness of the end cover 140 is less than 0.45mm, the end cover is easy to deform under certain internal pressure to generate radial displacement, so that the sealing effect between the end cover 140 and the sealing ring 150 is affected; when the thickness of the end cap 140 is greater than 0.8mm, the compression ratio C1 of the sealing ring 150 between the first region 11311 and the end cap 140 is large, and the sealing ring 150 is easily broken due to overpressure, thereby causing seal failure. Preferably, in an example of the secondary battery 100 of the present utility model, the thickness of the end cap 140 is any value ranging from 0.45 to 0.8mm, and may be, for example, 0.45mm, 0.55mm, 0.8mm, or the like. In the embodiment, the thickness dimension of the end cover 140 is limited within the range of 0.45-0.8 mm, so that the end cover 140 can be ensured to have certain strength and rigidity, the deformation of the end cover 140 in the using process is reduced, and the sealing stability of the end cover 140 is improved; and the compression ratio C1 is not excessively large, so that the probability of seal failure caused by breakage of the seal ring 150 can be reduced.

Because the internal pressure of the secondary battery 100 will be continuously increased during use, at this time, the end cap 140 will expand to the outside of the housing 110 under the action of the internal pressure, and then generate displacement moving toward the axis of the secondary battery 100 in the radial direction, which will further result in a decrease in the effective sealing area between the first groove wall 1131 and the sealing ring 150, thereby reducing the sealing effect between the sealing ring 150 and the first groove wall 1131. Preferably, referring to fig. 4 and 5, in an example of the secondary battery 100 of the present utility model, the outer edge of the end cap 140 is disposed at least 0.1mm beyond the outer edge dimension L of the case connecting part 131 in the radial direction of the secondary battery 100, for example, may be 0.1mm, 0.5mm, 1mm, or the like. Since the maximum radial displacement generated by the end cap 140 is less than 0.1mm during the entire life cycle of the secondary battery 100, in this embodiment, the dimension L of the outer edge of the end cap 140 beyond the outer edge of the case connecting portion 131 is set to be at least 0.1mm, so that the effective sealing area between the sealing ring 150 and the first groove wall 1131 is always non-zero during the entire life cycle of the secondary battery 100, thereby further reducing the probability of failure of the sealing between the sealing ring 150 and the first groove wall 1131, improving the sealing effect of the end cap 140 at the opening 112 of the case 110, and ensuring the cycle life and the charge-discharge performance of the secondary battery 100.

In an example of the secondary battery 100 of the present utility model, the thickness of the case 110 may be any value in the range of 0.3 to 0.6mm, for example, 0.3mm, 0.4mm, 0.6mm, or the like. The thickness of the housing 110 is related to the mechanical strength of the housing 110, and the greater the thickness of the housing 110, the higher the mechanical strength of the housing 110, so that the greater the compression force generated at the flange portion 114 of the housing 110, the better the strength and rigidity at the mechanical seal, and the more beneficial the improvement of the compression rate of the seal ring 150 between the end cover 140 and the first region 11311, so that the sealing effect between the seal ring 150 and the first groove wall 1131 can be improved; and the greater the thickness of the case 110, the greater the mass of the case 110, thereby reducing the energy density of the secondary battery 100. In the present embodiment, by limiting the thickness of the housing 110 to be within the range of 0.3-0.6 mm, the mechanical strength of the housing 110 can meet the mechanical seal strength requirement of the flange portion 114 at the opening 112, so as to ensure that the compression ratio between the sealing ring 150 and the first groove wall 1131 meets the sealing performance requirement; while not excessively increasing the mass of the case 110 and reducing the influence on the energy density of the secondary battery 100.

To further secure the sealing effect between the sealing ring 150 and the first groove wall 1131, in an example of the secondary battery 100 of the present utility model, a side of the first sealing part 152 facing the first groove wall 1131 is at least partially surface-coated with a sealant. The type of the sealant may be selected from various types, for example, silicone sealant, polyurethane sealant, butyl sealant, etc., and preferably, in this embodiment, the sealant is a silicone sealant. The position of application of the sealant on the first sealing portion 152 may be selected in various ways, for example, the sealant may be applied on the entire surface facing the first groove wall 1131 side, or the sealant may be applied only on a partial region facing the first groove wall 1131 side, which is not particularly limited. In the present embodiment, the first sealing portion 152 is coated with the sealant on the entire surface facing the first groove wall 1131 side. Because the sealant has a certain elasticity after solidification, when there is an installation gap at the position where the first sealing portion 152 abuts against the first groove wall 1131, the sealant can fill the gap, and eliminate the gap, thereby improving the sealing performance between the sealing ring 150 and the first groove wall 1131.

Referring to fig. 4 and 8, in an example of the secondary battery 100 of the present utility model, the current collecting member 130 further includes a connection arm 134 and a limiting portion 135, one end of the connection arm 134 is connected to the case connection portion 131, the other end of the connection arm 134 is connected to the tab connection portion 133, the limiting portion 135 is formed by the case connection portion 131 extending toward the electrode assembly 120 side in the height direction of the secondary battery 100, and the limiting portion 135 is at least partially abutted against the inner sidewall of the rolling groove 113. The limiting part 135 and the shell connecting part 131 can be integrally connected or welded, so long as the requirement of the connecting strength of the limiting part 135 can be met; in the present embodiment, the limiting portion 135 and the housing connecting portion 131 are integrally connected by press forming, so that the assembly time between the limiting portion 135 and the housing connecting portion 131 can be saved, and the assembly efficiency of the current collecting member 130 can be improved. The specific structure of the stopper 135 is not limited, and may be, for example, a flat plate structure, a cylindrical structure, an arc plate structure, or any other structure that can abut against the inner side wall of the rolling groove 113. Preferably, in order to facilitate molding and reduce production cost, in an example of the present utility model, the limiting portion 135 has a flat plate structure. The number and specific positions of the limiting portions 135 are not limited, but preferably, in the present embodiment, two limiting portions 135 are disposed on each housing connecting portion 131, and the two limiting portions 135 are located on two sides of the connecting arm 134 respectively. By the arrangement, the two sides of the shell connecting part 131 can form supporting points, so that better positioning strength and positioning accuracy can be obtained in the positioning process.

Through set up spacing portion 135 on casing connecting portion 131, can play radial spacing effect at casing connecting portion 131 in-process of pushing down, can reduce the radial displacement volume of casing connecting portion 131 on first cell wall 1131 to the extrusion force that radial direction produced between casing connecting portion 131 and sealing washer 150 can be reduced, so can reduce sealing washer 150 because the extrusion force is too big and the probability of being crushed, improves sealing washer 150's life.

Referring to fig. 11, in an embodiment of a battery pack 200 of the present utility model, the battery pack 200 includes a case 210 and at least one secondary battery 100; the case 210 includes a first case portion 211 and a second case portion 212, the first case portion 211 and the second case portion 212 are covered with each other to form an accommodating space in which the plurality of secondary batteries 100 are accommodated, and the plurality of secondary batteries 100 may be connected in series and/or in parallel. The battery pack 200 may be, for example, a battery module, a battery pack, or the like.

Referring to fig. 12, in an example of the electronic device 300 of the present utility model, the electronic device 300 includes a working portion 310 and a battery pack 200, and the working portion 310 is electrically connected to the battery pack 200 to obtain power support. The working part 310 may be a unit part capable of taking the electric power of the battery pack 200 and making a corresponding work, such as a blade rotation unit of a fan, a dust suction working unit of a dust collector, a wheel driving unit in an electric vehicle, etc. The electronic device 300 may be a vehicle, a cellular phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. The vehicle can be a fuel oil vehicle, a fuel gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range-extended vehicle; spacecraft including airplanes, rockets, space planes, spacecraft, and the like; the electric toy includes fixed or mobile electric toys, such as a game machine, an electric car toy, an electric ship toy, and an electric airplane toy; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railroad power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete shakers, and electric planers, among others. The embodiment of the present utility model is not particularly limited to the above-described electronic device 300. In an embodiment of the electronic device 300 of the present utility model, the electronic device 300 is a vehicle, the working portion 310 is a body of the vehicle, and the battery pack 200 is fixedly mounted on the body, so as to provide driving force for the vehicle, thereby realizing running of the vehicle.

The secondary battery 100 of the utility model improves the sealing performance of the sealing ring 150 at the position of the rolling groove 113 by adopting a mode of controlling the high size of the upper end to realize the control of the compression rate of the sealing ring 150, on one hand, because the high size of the upper end is convenient for measurement after the sealing is finished, whether the sealing of the sealing ring 150 at the position of the rolling groove 113 is qualified or not can be judged by measuring the high size of the upper end, and the secondary battery 100 with unqualified sealing is screened in advance, thereby reducing the subsequent testing pressure on the sealing performance of the secondary battery 100; on the other hand, the dimension control of the upper end height can be determined by the process parameters of the pier seal during sealing, so that the dimension adjustment of the upper end height can be realized by setting the process parameters of the pier seal, and the dimension of the upper end height is convenient to adjust and easy to control. Therefore, the utility model effectively overcomes some practical problems in the prior art, thereby having high utilization value and use significance. The above embodiments are merely illustrative of the principles of the present utility model and its effectiveness, and are not intended to limit the utility model. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the utility model. Accordingly, it is intended that all equivalent modifications and variations of the utility model be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims (10)

1. A secondary battery, characterized by comprising:

A housing including a cylindrical side wall having an opening at one end thereof, the side wall being formed with a rolling groove recessed toward the inside of the housing at a position close to the opening, the rolling groove including a first groove wall facing the opening side, the side wall of the opening side extending toward the center of the opening to form a burring portion;

an electrode assembly accommodated in the case, the rolling groove restricting movement of the electrode assembly in the case in a height direction of the secondary battery;

A current collecting member disposed in the case, the current collecting member being electrically connected with the electrode assembly, the current collecting member including a case connecting part fixedly connected with the first groove wall;

the end cover is arranged between the flanging part and the first groove wall and covers the opening;

The sealing ring is at least partially clamped between the end cover and the flanging part, and at least one other part of the sealing ring is clamped between the end cover and the first groove wall;

The distance between one side of the flanging part, which is away from the rolling groove, and one side of the first groove wall, which is away from the opening, is the height of the upper end, and the height of the upper end is 2.3-2.5 mm.

2. The secondary battery according to claim 1, wherein a minimum thickness of the sealing ring in a region between the case connecting portion and the end cap in a height direction of the secondary battery is t1, a thickness of the sealing ring beyond a free end of the rolling groove is t3, and a range of (t 3-t 1)/t 3 is 67 to 73%.

3. The secondary battery according to claim 2, wherein a minimum thickness of the seal ring in a region between the end cap and the burring is t2, and a range of (t 3-t 2)/t 3 is 23 to 37% in a height direction of the secondary battery.

4. The secondary battery according to claim 1, wherein the thickness of the case connecting part is 0.05 to 0.25mm.

5. The secondary battery according to claim 4, wherein the sealing ring has an initial thickness of 0.5 to 1.0mm.

6. The secondary battery according to claim 5, wherein the thickness of the end cap is 0.45 to 0.8mm.

7. The secondary battery according to claim 1, wherein an outer edge of the end cap exceeds an outer edge of the case connecting portion by at least 0.1mm in a radial direction of the secondary battery.

8. The secondary battery according to claim 6, wherein the thickness of the case is 0.3 to 0.6mm.

9. A battery pack comprising the secondary battery according to any one of claims 1 to 8.

10. An electronic device comprising the battery pack of claim 9.