CN220382277U - Secondary battery, battery pack, and electronic device - Google Patents

Secondary battery, battery pack, and electronic device Download PDF

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Publication number
CN220382277U
CN220382277U CN202321976982.9U CN202321976982U CN220382277U CN 220382277 U CN220382277 U CN 220382277U CN 202321976982 U CN202321976982 U CN 202321976982U CN 220382277 U CN220382277 U CN 220382277U
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CN
China
Prior art keywords
cover plate
secondary battery
electrode assembly
hole
tab
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Application number
CN202321976982.9U
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Chinese (zh)
Inventor
钱佳
车佩佩
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Vision Power Technology Hubei Co ltd
Yuanjing Power Technology Ordos Co ltd
Yuanyuan Power Technology Hebei Co ltd
Envision Power Technology Jiangsu Co Ltd
Envision Ruitai Power Technology Shanghai Co Ltd
Original Assignee
Vision Power Technology Hubei Co ltd
Yuanjing Power Technology Ordos Co ltd
Yuanyuan Power Technology Hebei Co ltd
Envision Power Technology Jiangsu Co Ltd
Envision Ruitai Power Technology Shanghai Co Ltd
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Application filed by Vision Power Technology Hubei Co ltd, Yuanjing Power Technology Ordos Co ltd, Yuanyuan Power Technology Hebei Co ltd, Envision Power Technology Jiangsu Co Ltd, Envision Ruitai Power Technology Shanghai Co Ltd filed Critical Vision Power Technology Hubei Co ltd
Priority to CN202321976982.9U priority Critical patent/CN220382277U/en
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Publication of CN220382277U publication Critical patent/CN220382277U/en
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • Sealing Battery Cases Or Jackets (AREA)

Abstract

The utility model provides a secondary battery, a battery pack and an electronic device, the secondary battery includes: the electrode assembly includes a case, a terminal, an electrode assembly, a first current collecting member, and a cap plate assembly. The shell comprises an end wall and a side wall, and the side wall is provided with an opening; the terminal is installed through the end wall; the electrode assembly comprises a first tab and a second tab, and the second tab is electrically connected with the terminal; the first current collecting member is arranged at one end of the electrode assembly facing the opening and is welded with the first tab; the cover plate assembly includes a first cover plate, a second cover plate, and a third cover plate. The first cover plate is covered on the opening and is welded with the side wall, the first cover plate is welded with the first current collecting component, the first cover plate comprises a through hole, the second cover plate is welded on the first cover plate and seals the through hole, and the second cover plate comprises a liquid injection hole; the third cover plate is fixed on the second cover plate and seals the liquid injection hole, and the utility model can solve the problem that the first current collecting component is easy to be extruded in the sealing process, so that the connection is invalid.

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
At present, large cylindrical batteries are increasingly favored by various cart enterprises due to the advantages of high safety, long service life, excellent quick charge performance, excellent battery consistency and low production cost.
Currently, the housing of large cylindrical batteries is typically charged such that the housing itself serves as one of the positive and negative electrodes when the batteries are grouped. The electric connection mode between the electrode assembly in the shell and the shell is as follows: the electrode assembly is connected with a first current collecting member welded on the side wall of the case to realize electrification of the case. In the subsequent battery sealing process, the side wall of the case is subjected to a large compressive stress, so that the connection between the first current collecting member and the case is at risk of failure. It is therefore desirable to provide a secondary battery, a battery pack, and an electronic device to solve the above-described problems.
Disclosure of Invention
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 technical problem that the first current collecting member is welded to the side wall of the case and is easily extruded during the sealing process, thereby causing connection failure.
To achieve the above and other related objects, the present utility model provides a secondary battery comprising: the electrode assembly includes a case, a terminal, an electrode assembly, a first current collecting member, and a cap plate assembly. The housing comprises an end wall and a side wall surrounding the end wall, and an opening is formed at one end of the side wall, which is away from the end wall; a terminal is sealingly and insulatively mounted through the end wall; an electrode assembly housed within the case, the electrode assembly including a first tab facing the opening and a second tab facing the end wall, the second tab being electrically connected to the terminal; the first current collecting member is arranged at one end of the electrode assembly facing the opening, and the first current collecting member is connected with the first tab in a welding way; the cover plate assembly includes a first cover plate, a second cover plate, and a third cover plate. The first cover plate is covered on the opening and is welded with the side wall, the first cover plate is welded with the first current collecting member, the first cover plate comprises a through hole, the second cover plate is welded on the first cover plate and seals the through hole, and the second cover plate comprises a liquid injection hole; the third cover plate is fixed on the second cover plate and seals the liquid injection hole.
In an embodiment of the secondary battery of the present utility model, the first current collecting member includes a cap plate welding portion and a tab welding portion, the cap plate welding portion is welded to the first cap plate, and the tab welding portion is welded to the first tab.
In an embodiment of the secondary battery of the present utility model, a projection of the through hole on the first current collecting member covers the tab welding portion in a height direction of the secondary battery.
In an embodiment of the secondary battery of the present utility model, a thickened portion is disposed on a side of the second cover plate, which is close to the electrode assembly, and the liquid injection hole is disposed on the thickened portion and penetrates through the thickened portion in a thickness direction of the thickened portion.
In an embodiment of the secondary battery of the present utility model, a side of the third cover plate facing the liquid injection hole is provided with a relief portion.
In an embodiment of the secondary battery of the present utility model, the second cover plate is provided with a first recess, the liquid injection hole is disposed in the first recess, and the third cover plate is at least partially accommodated in the first recess.
In an embodiment of the secondary battery of the present utility model, a side of the third cap plate facing away from the electrode assembly does not protrude beyond the first recess.
In an embodiment of the secondary battery of the present utility model, the bottom of the first recess includes a first land area, the first land area is disposed around the liquid injection hole, and the third cap plate is mounted on a side of the first land area facing away from the electrode assembly and is welded to the first land area.
In an embodiment of the secondary battery of the present utility model, a recess is disposed at a side of the second cap plate and the third cap plate facing away from the electrode assembly, and the recess corresponds to a welding position of the second cap plate and the third cap plate.
In an embodiment of the secondary battery of the present utility model, the first cover plate is provided with a second recess, the through hole is disposed in the second recess, and the second cover plate is at least partially accommodated in the second recess.
In an embodiment of the secondary battery of the present utility model, a side of the second cap plate facing away from the electrode assembly does not protrude beyond the second recess.
In an embodiment of the secondary battery of the present utility model, the bottom of the second recess includes a second land, the second land is disposed around the through hole, and the second cap plate is mounted on a side of the second land facing away from the electrode assembly and is welded to the second land.
In an embodiment of the secondary battery of the present utility model, a first guide structure is provided between the second cover plate and the second recess; a second guide structure is provided between the third cover plate and the first recess.
In an embodiment of the secondary battery of the present utility model, the first guide structure and/or the second guide structure comprises one or a combination of the following: rounded corners, chamfers or slopes.
In an embodiment of the secondary battery of the present utility model, the first guide structure and/or the second guide structure includes a first annular inclined surface surrounding the through hole and contracted from a side facing away from the electrode assembly toward the electrode assembly, and the first annular inclined surface has an inclination angle of 95 to 160 °.
In an embodiment of the secondary battery of the present utility model, the cap plate welding part is disposed between the first cap plate and the electrode assembly, and one side facing away from the electrode assembly is welded to the first cap plate.
In an embodiment of the secondary battery of the present utility model, a side surface of the cap plate welded portion facing away from the first cap plate includes a welding mark.
In an embodiment of the secondary battery of the present utility model, the surface of the first cap plate facing away from the cap plate welded portion has no solder marks thereon.
In an embodiment of the secondary battery of the present utility model, an inner solder is included on a surface of the cover plate welding portion facing away from the first cover plate, an outer solder is included on a surface of the first cover plate facing away from the cover plate welding portion, and a projection area of the inner solder is greater than or equal to a projection area of the outer solder along a height direction of the secondary battery.
In an embodiment of the secondary battery of the present utility model, the cap plate welding portion is welded to an edge of the through hole, and the tab welding portion is recessed toward the electrode assembly side and is welded to the first tab.
In an embodiment of the secondary battery of the present utility model, the housing is cylindrical, the first cover plate is annular, and the through hole and the first cover plate are coaxially disposed.
In an embodiment of the secondary battery of the present utility model, the outer diameter of the side wall is D, the tab welding parts are distributed in an annular region centered on the center of the end face of the electrode assembly, and the inner diameter of the annular region is greater than or equal to 0.25D and the outer diameter is less than or equal to 0.87D.
In an embodiment of the secondary battery of the present utility model, the inner diameter of the annular region is greater than or equal to 12mm, and the outer diameter of the annular region is less than or equal to 40mm.
In an embodiment of the secondary battery of the present utility model, the diameter of the case is D, and the diameter of the through hole is greater than or equal to 0.43D and less than or equal to 0.96D.
In an embodiment of the secondary battery of the present utility model, the second cover plate is provided with an explosion-proof structure.
In one embodiment of the secondary battery of the present utility model, the explosion-proof structure includes a score provided on the cap plate, and an opening of the score is adjacent to the electrode assembly.
In an embodiment of the secondary battery of the present utility model, the explosion-proof structure includes a solder seal between the first cover plate and the second cover plate.
In an embodiment of the secondary battery of the present utility model, the first cap plate includes a protrusion matched with the opening, the protrusion protruding toward the electrode assembly side and being disposed around the through-hole, the protrusion being for blocking laser light when welding the first cap plate and the opening.
In one embodiment of the secondary battery of the present utility model, the height of the convex portion is 0.1 to 5mm and the radial width of the convex portion is 1 to 10mm in the height direction of the secondary battery.
In one embodiment of the secondary battery of the present utility model, the height of the protruding portion is 0.5 to 2.5mm.
In an embodiment of the secondary battery of the present utility model, the first cover plate further includes a limiting portion disposed around the protruding portion, and an end surface of the side wall abuts against the limiting portion.
In an embodiment of the secondary battery of the present utility model, the solder between the first cover plate and the opening is disposed around the opening and is located on the contact surface between the limiting portion and the side wall.
In an embodiment of the secondary battery of the present utility model, the cap plate welding part is welded to a side of the protrusion facing the electrode assembly.
In an embodiment of the secondary battery of the present utility model, the case has a cylindrical shape, and a side of the protrusion facing the electrode assembly has an annular plane disposed coaxially with the case.
In an embodiment of the secondary battery of the present utility model, the electrode assembly includes a central through hole, and the first current collecting member is provided at a central portion thereof with an opening, a projection of which covers a projection of the central through hole in a height direction of the secondary battery.
In an embodiment of the secondary battery of the present utility model, the projection of the opening covers the projection of the pouring hole in the height direction of the secondary battery.
In an embodiment of the secondary battery of the present utility model, a groove corresponding to the protrusion is formed on a surface of the first cap plate facing away from the electrode assembly, and the groove has a depth of 0.1 to 5mm.
In an embodiment of the secondary battery of the present utility model, a distance from the end surface of the first tab to the outer surface of the cap plate is 0.6-4 mm.
The utility model also provides a battery pack comprising the secondary battery as described in any one of the above.
The utility model also provides various electronic equipment which comprises the battery pack.
In the secondary battery, the outer edge of the first cover plate is welded with the side wall and seals the opening, the first current collecting member is welded with the first cover plate, and the first current collecting member is not connected with the side wall of the shell, so that the technical problem that the first current collecting member is welded on the side wall of the shell and is easy to be extruded in the sealing process to cause connection failure can be solved. Meanwhile, the sealed packaging of the secondary battery can be realized without the rolling groove and the upsetting process on the shell, the process is simplified, the assembly efficiency is higher, the height of the rolling groove can be saved, and the space utilization rate of the secondary battery is improved.
In the utility model, the first current collecting member and the first cover plate can be welded into a whole before the secondary battery is assembled, and then the first current collecting member and the electrode assembly are welded through the through hole on the first cover plate, so that the assembly steps are reduced. And the first current collecting component and the first cover plate are welded before assembly, laser can irradiate from one side of the first current collecting component, penetrate through the relatively thin first current collecting component to the first cover plate, and the welding process window is large, so that the welding efficiency is high.
In addition, in the utility model, the second cover plate and the third cover plate are combined to realize the sealing of the through hole on the first cover plate, and after the second cover plate and the first cover plate are welded, liquid injection can be carried out from the liquid injection hole, so that the heat influence of larger welding area and longer welding time on electric liquid connection when the second cover plate and the first cover plate are welded can be reduced.
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 required in the embodiments or the description of 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 drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic view showing the overall structure of an embodiment of a secondary battery according to the present utility model;
FIG. 2 is an enlarged view of a portion of region I of FIG. 1;
FIG. 3 is an enlarged view of a portion of FIG. 2 with the third cover plate removed;
FIG. 4 is an enlarged view of a portion of FIG. 3 after the second cover plate has been removed;
fig. 5 is a cross-sectional view of a secondary battery according to an embodiment of the present utility model after welding a first cap plate to a first current collecting member;
fig. 6 is a three-dimensional view of a secondary battery according to an embodiment of the present utility model after welding a first cap plate and a first current collecting member;
FIG. 7 is an enlarged view of a portion of region II of FIG. 2;
FIG. 8 is an enlarged view of a portion of region III of FIG. 7;
FIG. 9 is an enlarged view of a portion of region IV of FIG. 4;
fig. 10 is a three-dimensional view of a first cap plate in another view angle in an embodiment of the secondary battery according to the present utility model;
fig. 11 is a schematic view illustrating connection between a first cap plate and a first current collecting member in another embodiment of a secondary battery according to the present utility model;
fig. 12 is a schematic view illustrating connection of a first cap plate and a first current collecting member in a further embodiment of the secondary battery according to the present utility model;
fig. 13 is a partial three-dimensional view of one side of an opening in an embodiment of a secondary battery according to the present utility model;
fig. 14 is a partial three-dimensional view of one side of the rear opening of the secondary battery according to an embodiment of the present utility model with the third cap plate removed;
Fig. 15 is a partial three-dimensional view of one side of the rear opening of the secondary battery according to an embodiment of the present utility model with the second and third cap plates removed;
FIG. 16 is an enlarged view of a portion of region II of FIG. 2 according to another embodiment of the present utility model;
FIG. 17 is a schematic diagram of an embodiment of an electronic device according to the present utility model;
fig. 18 is a schematic view of an embodiment of a battery module according to the present utility model.
Description of element reference numerals
1. An electronic device; 10. a battery module; 11. a working section; 101. a case; 102. a case cover; 100. a secondary battery; 110. a housing; 111. an end wall; 112. a sidewall; 113. an opening; 120. a terminal; 130. an electrode assembly; 131. a second lug; 132. a first tab; 133. a central through hole; 134. a second current collecting member; 140. a cover plate assembly; 141. a first cover plate; 1411. a through hole; 1412. a convex portion; 1413. a limit part; 1414. a second concave portion; 1415. a first annular ramp; 1416. a second platform region; 1417. an annular plane; 1418. a groove; 142. a second cover plate; 1421. an explosion-proof structure; 1422. a cylindrical section; 1423. a second annular ramp; 1424. a liquid injection hole; 1425. a first concave portion; 1426. a thickened portion; 1427. a first platform region; 143. a first current collecting member; 1431. a tab welding part; 1432. a cover plate welding part; 1433. opening holes; 1441. a first solder printing; 1442. a second solder printing; 1443. third welding; 1444. fourth welding and printing; 145. a first guide structure; 146. a gap; 147. a third cover plate; 1471. welding and printing the inner side; 1472. welding and printing the outer side; 1473. an avoidance unit; 148. a recessed portion; 1481. a first ring groove; 1482. a second ring groove; 149. a second guide structure; 1491. a third annular incline; 1492. and a fourth annular inclined surface.
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 18, the present utility model provides a secondary battery 100, a battery pack 10 and an electronic device 1 including the secondary battery 100, in which the secondary battery 100 has no connection between a first current collecting member 143 and a sidewall 112 of a case 110, so that the technical problem that the first current collecting member 143 is welded on the sidewall 112 of the case 110 and easily pressed during sealing to cause connection failure can be improved.
Referring to fig. 1 and 2, the secondary battery 100 includes: the electrode assembly 130 includes a case 110, a terminal 120, an electrode assembly 130, a first current collecting member 143, and a cap plate assembly 140.
Referring to fig. 1 and 2, the housing 110 includes an end wall 111 and a side wall 112 surrounding the end wall 111, and the connection between the end wall 111 and the side wall 112 can be made in a variety of ways, such as by integrally stamping, integrally casting, or separately welding, as long as a stable sealing and electrical connection is achieved. The side wall 112 may be, but not limited to, a cylindrical ring or a ring around any other closed-loop contour that can match the end wall 111, and in this embodiment, the outer edge of the end wall 111 is circular, the side wall 112 is cylindrically formed around the outer edge of the end wall 111, and a circular opening 113 is formed at an end of the side wall 112 facing away from the end wall 111. A housing 110 surrounded by the end wall 111 and the side wall 112 has a housing chamber formed therein for housing the electrode assembly 130, an electrolyte (not shown), and other necessary components of the battery. Specifically, the diameter of the case 110 may be sized according to the specific dimensions of the electrode assembly 130, such as 18mm, 21mm, 46mm, 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. 1 and 2, an electrode assembly 130 is received in a case 110, and the electrode assembly 130 is a component in which an electrochemical reaction occurs in the secondary battery 100. One or more electrode assemblies 130 may be contained within the case 110. The electrode assembly 130 is mainly formed by winding or stacking a positive electrode tab and a negative electrode tab, and a separator is generally provided between the positive electrode tab and the negative electrode tab. The positive electrode plate comprises a positive electrode current collector and a positive electrode active substance, and the positive electrode active substance is coated on the surface of the positive electrode current collector; the positive electrode current collector includes a coated region coated with an active material and an uncoated region uncoated with the active material, and the uncoated region is wound to form a positive electrode tab of the electrode assembly. The negative electrode plate comprises a negative electrode current collector and a negative electrode active substance, and the negative electrode active substance is coated on the surface of the negative electrode current collector; the negative electrode current collector includes a coated region coated with an active material and an uncoated region uncoated with the active material, and the uncoated region is wound to form a negative electrode tab of the electrode assembly. Taking the lithium ion secondary battery 100 as an example, the material of the positive electrode current collector may be aluminum, the positive electrode active material 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 negative electrode current collector may be copper, the negative electrode active material includes a negative electrode active material, and the negative electrode active material may be carbon or silicon, etc. 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. The electrode assembly 130 in the present utility model includes a second tab 131 facing the end wall 111 and a first tab 132 facing the opening 113, where the second tab 131 may be a positive tab or a negative tab, and the first tab 132 is opposite to the second tab 131 in electrical property, and when the second tab 131 is a positive tab, the first tab 132 is a negative tab, and when the second tab 131 is a negative tab, the first tab 132 is a positive tab, and the second tab 131 is electrically connected to the terminal 120 through a second current collecting member 134, and the first current collecting member 143 is disposed at an end of the electrode assembly 130 facing the opening 113 and is welded to the first tab 132. In this embodiment, the second tab 131 is a positive tab, the terminal 120 is electrically connected to the second tab 131 to be positively charged, the first tab 132 is a negative tab, and the opening 113 side of the case 110 opposite to the end wall 111 is electrically connected to the first tab 132 to be negatively charged.
Referring to fig. 1 and 2, the terminal 120 passes through the end wall 111 and is insulated from the end wall 111. The structural form of the terminal 120 may be any suitable form capable of being electrically connected to the second electrode tab 131 of the electrode assembly 130 through the end wall 111, for example, the cross section may be circular, square, prismatic or a profiled contour capable of achieving stable electrical conduction, one end of the terminal 120 facing the electrode assembly 130 is directly electrically connected to the second electrode tab 131 through the end wall 111 or is electrically connected through indirect switching, in this embodiment, the terminal 120 is electrically connected to the second electrode tab 131 through switching of the second current collecting member 134, one end of the terminal 120 facing the opening 113 is welded to the second current collecting member 134, and one side of the second current collecting member 134 facing away from the terminal 120 is welded to the second electrode tab 131. One end of the terminal 120 facing away from the electrode assembly 130 is exposed to the outside of the housing 110 to form a corresponding electrode, and the electrical property of the terminal 120 may be positive or negative, for example, in one embodiment, the polarity of the second electrode 131 is a negative electrode, the terminal 120 is a negative electrode, the housing 110 forms a corresponding positive electrode, and in another embodiment, the polarity of the second electrode 131 is a positive electrode, the terminal 120 is a positive electrode, and the housing 110 forms a corresponding negative electrode. In the present embodiment, the end wall 111 is provided with a terminal 120 mounting hole, and the terminal 120 is hermetically and insulatively inserted into the terminal 120 mounting hole. Such a case 110 structure can improve installation efficiency and is more excellent in assemblability and sealability than the case 110 form of the both end openings 113. The terminal 120 is made of a metal material having conductivity. The material of the terminal 120 may be aluminum (Al). If the material of the terminal 120 is aluminum, a caulking process can be easily performed, and 10 series aluminum having a relatively low resistance can be applied. If the terminal 120 has a first polarity, the terminal 120 is electrically insulated from the housing 110 having a second polarity. Electrical insulation between the terminals 120 and the end walls 111 of the housing 110 may be achieved in various ways. Insulation may be achieved, for example, by an insulating washer interposed between the terminal 120 and the end wall 111. Alternatively, insulation may be achieved by forming an insulation coating layer on a portion of the terminal 120. Alternatively, any method of structurally firmly fixing the terminal 120 such that the terminal 120 and the housing 110 are not in contact with each other may be applied. Alternatively, some of the above methods may be applied in combination.
Referring to fig. 2, in the present utility model, the materials of the first current collecting member 143 and the second current collecting member 134 are selected according to the polarity of the tab connected thereto, for example, if the second current collecting member 134 is connected to the positive electrode tab, the second current collecting member 134 may be made of aluminum metal, and the material of the first current collecting member 143 and the negative electrode tab may be made of copper metal opposite to the second current collecting member 134. If the second current collecting member 134 is connected to the negative electrode tab, the second current collecting member 134 may be made of copper, and in this case, the first current collecting member 143 is connected to the positive electrode tab opposite to the second current collecting member 134, and the first current collecting member 143 may be made of aluminum. The shape and structure of the second current collecting member 134 and the first current collecting member 143 are not limited either, and are suitable in order to enable a stable and reliable electrical connection relationship.
Referring to fig. 1, 2, 7 and 16, the cover assembly 140 seals the opening 113. The cover assembly 140 includes a first cover 141, a second cover 142, and a third cover 147. The outer edge of the first cover plate 141 has a shape corresponding to the shape of the opening 113, and is welded to the sidewall 112 and seals the opening 113. The welding may be a welding that can achieve a seal at the welding location, such as welding the welding head in a direction perpendicular to the side wall 112 (i.e., the X direction in fig. 7) and moving relative to the secondary battery 100 in the circumferential direction during the welding process, thereby forming a first weld 1441 on the side wall 112; or as shown in fig. 16, the welding head welds in the height direction of the secondary battery 100 (i.e., in the direction from the opening 113 to the end wall 111) and rotates relatively to the secondary battery 100 along the shape of the outer edge of the first cover plate 141 during welding, so that the position where the outer edge of the first cover plate 141 contacts the end face of the side wall 112 forms a closed loop first weld 1441. Note that, the shape of the first solder 1441 in fig. 7 or the shape of the first solder 1441 in fig. 16 is merely illustrative, and is not limited to the shape of the first solder 1441. The first cover plate 141 includes a through hole 1411, and the shape of the through hole 1411 is not limited, and may be a circular shape, an elliptical shape, or the like having a closed contour, and the through hole 1411 penetrates the first cover plate 141 in the thickness direction of the first cover plate 141. The welding position and the shape of the welding stamp of the first cap plate 141 and the first current collecting member 143 are not limited as long as the stable conductive connection of the first cap plate 141 and the first current collecting member 143 can be achieved.
Referring to fig. 1 and 2, the second cover 142 is fixed to the first cover 141 and covers the through hole 1411; the second cover plate 142 covers the through-hole 1411 in various ways as long as it can effectively seal the through-hole 1411, for example, the second cover plate 142 is welded to the first cover plate 141 and seals the through-hole 1411. The shape of the second cover plate 142 may correspond to the through hole 1411, for example, the second cover plate 142 is circular when the through hole 1411 is circular, and the second cover plate 142 is square when the through hole 1411 is square. The shape of the second cover plate 142 may not correspond to the shape of the through hole 1411, for example, the second cover plate 142 may be square capable of covering the through hole 1411 when the through hole 1411 is circular, and the second cover plate 142 may be circular capable of covering the through hole 1411 when the through hole 1411 is square. The second cover 142 includes a filling hole 1424, and the filling hole 1424 may be disposed at any position on the second cover 142, preferably, the filling hole 1424 is disposed in the middle of the second cover 142 in an embodiment, and the shape and size of the filling hole 1424 are not limited, preferably, so as to be able to match with the electrolyte filling device. In this embodiment, the injection hole 1424 is a circular hole, and the diameter D1 is 3-6 mm, so that the injection hole has a large versatility in the diameter range, and realizes the matching with a plurality of injection devices. Of course, in other embodiments, the fill port 1424 may be of other suitable dimensions.
Referring to fig. 1 and 2, a third cover 147 is fixed to the second cover 142 and covers the injection hole 1424. As long as the injection hole 1424 can be effectively sealed, there are various ways in which the third cover plate 147 seals the injection hole 1424, for example, the third cover plate 147 is welded on the second cover plate 142 and seals the injection hole 1424, or a structural adhesive with a certain strength and not corroded by electrolyte is used to realize sealing adhesion between the second cover plate 142 and the third cover plate 147, etc., the shape of the third cover plate 147 may correspond to the injection hole 1424, for example, when the injection hole 1424 is circular, the third cover plate 147 is circular, and when the injection hole 1424 is square, the third cover plate 147 is square. The shape of the third cover plate 147 may not correspond to the shape of the injection hole 1424, for example, when the injection hole 1424 is circular, the third cover plate 147 is square so as to cover the injection hole 1424, and when the injection hole 1424 is square, the third cover plate 147 is circular so as to cover the injection hole 1424.
In the secondary battery 100, the first current collecting member 143 is not connected to the side wall 112 of the case 110, so that the technical problem that the first current collecting member 143 is welded to the side wall 112 of the case 110 and is easy to be extruded in the sealing process to cause connection failure in the prior art can be improved.
In the secondary battery 100 of the present utility model, after the electrode assembly 130 is mounted in the case 110, the assembly process of one side of the opening 113 includes:
s1: welding the first current collecting member 143 to the first cap plate 141 as one body;
s2, welding the outer edge of the first cover plate 141 with the side wall 112 of the opening 113;
s3, welding the first current collecting member 143 with the first tab 132 from the through hole 1411 of the first cover plate 141;
s4, sealing and covering the second cover plate 142 on the through hole 1411 of the first cover plate 141;
s5, injecting electrolyte into the shell 110 from the injection hole 1424 on the second cover plate 142;
and S6, sealing and covering the third cover plate 147 on the liquid injection hole 1424 of the second cover plate 142.
As can be seen from the above assembly process, the first current collecting member 143 and the first cap plate 141 may be welded as one body before the secondary battery is assembled, and then the first current collecting member 143 and the first tab 132 of the electrode assembly 130 are welded through the through hole in the first cap plate 141, so that the assembly step after the electrode assembly 130 is mounted in the case 110 is reduced, and the first current collecting member 143 and the first cap plate 141 are welded before the assembly, laser may be irradiated from one side of the first current collecting member 143, penetrating the relatively thin first current collecting member 143 to the first cap plate 141, and the welding process window is large and the welding efficiency is high.
In addition, in the present utility model, the second cover plate 142 and the third cover plate 147 are combined to realize the sealing of the through hole 1411 on the first cover plate 141, and the liquid injection can be performed from the liquid injection hole 1424 after the second cover plate 142 and the first cover plate 141 are welded, so that the thermal influence of a larger welding area and a longer welding time on the electric liquid connection can be prevented when the second cover plate 142 and the first cover plate 141 are welded.
Referring to fig. 2 and 7, in an embodiment of the secondary battery 100 according to the present utility model, the first current collecting member 143 includes a cap plate welding portion 1432 and a tab welding portion 1431, the shape of the cap plate welding portion 1432, the shape of the tab welding portion 1431, and the relative positions of the cap plate welding portion 1432 and the tab welding portion 1431 are not limited, in an embodiment, the cap plate welding portion 1432 may be a circular ring shape along the projection of the height direction of the secondary battery 100, the projection of the tab welding portion 1431 is distributed inside the projection of the cap plate welding portion 1432, the cap plate welding portion 1432 is welded to the first cap plate 141, and the tab welding portion 1431 is welded to the first tab 132.
Referring to fig. 1 to 2 and 7, in an embodiment of the secondary battery 100 according to the present utility model, the secondary battery 100 is a cylindrical secondary battery 100, the sidewall 112 of the case 110 is formed in a cylindrical shape around the secondary battery 100, and the projection of the through hole 1411 on the first current collecting member 143 covers the tab welding portion 1431 in the height direction of the secondary battery 100 (i.e., the axial direction of the cylinder). In this arrangement, after the welding of the first cover 141 and the side wall 112 is completed, the tab welding portion 1431 is exposed from the through hole 1411 on the side facing away from the electrode assembly 130, and the tab welding portion 1431 and the first tab 132 can be welded through the through hole 1411 from the outside of the first cover 141.
Referring to fig. 2 to 3, in an embodiment of the secondary battery 100 of the present utility model, a thickened portion 1426 is disposed on a side of the second cover 142 close to the electrode assembly 130, and the thickened portion 1426 and the second cover 142 are connected by, but not limited to, integral connection, welding, bonding, etc., wherein a dispensing hole 1424 of the thickened portion 1426 is disposed through the thickened portion 1426, and the thickness of the side wall 112 is matched with that of the sealing nail. The setting of thickening portion 1426 can strengthen the intensity of second apron 142 on the one hand, and on the other hand can form thicker pore wall around annotating liquid hole 1424, like this before third apron 147 installs, can adopt sealed nail to annotate liquid hole 1424 shutoff as required, prevents that the foreign matter from getting into, also prevents that the electrolyte volatilizes.
Referring to fig. 2 to 3, in an embodiment of the secondary battery 100 of the present utility model, the inner edge of the second cover 142 includes a first concave portion 1425, the shape of the first concave portion 1425 may correspond to the third cover 147, for example, when the outer contour of the third cover 147 is circular, the projection of the outer contour of the first concave portion 1425 may be circular, the shape of the first concave portion 1425 may not correspond to the third cover 147, for example, when the outer contour of the third cover 147 is circular, the first concave portion 1425 may be square to accommodate the third cover 147. The depth of the first recess 1425 is such that the third cover 147 is at least partially accommodated in the height direction. The liquid injection hole 1424 is provided on the bottom wall of the first recess 1425; the third cover plate 147 is at least partially received in the first recess 1425 in the height direction, and preferably, a side of the third cover plate 147 facing away from the electrode assembly 130 does not protrude beyond the first recess 1425. This reduces the area of engagement with the battery tray when the opening 113 is placed downward, and enables stable support.
Referring to fig. 2 to 3, in an embodiment of the secondary battery 100 of the present utility model, the bottom of the first recess 1425 includes a first land 1427, the first land 1427 is integrally connected with the sidewall 112 of the first recess 1425, the first land 1427 is disposed around the injection hole 1424, and the third cap plate 147 is mounted on a side of the first land 1427 facing away from the electrode assembly 130 and is welded to the first land 1427 of the first recess 1425. The third cover plate 147 may be welded to the side wall 112 and the bottom wall of the first recess 1425 in a sealing manner.
Referring to fig. 2 and 9, in an embodiment of the secondary battery 100 of the present utility model, a relief portion 1473 is disposed on a side of the third cover 147 facing the injection hole 1424, and the relief portion 1473 is recessed from a side close to the electrode assembly 130 toward a side away from the electrode assembly 130. The relief portion 1473 is annular and recessed toward the side away from the electrode assembly 130 at equal depth, and the relief portion 1473 can reduce the contact area between the third cover plate 147 and the first land area 1427, and can reduce the loose fit caused by the deformation or the excessive fit area. In this embodiment, the relief portion 1473 is annular and coaxially covers the upper portion of the injection hole 1424, and the depth of the relief portion 1473 is preferably 0.1 to 0.5mm, which can reduce the fitting area without affecting the axial dimension of the third cover plate 147.
Referring to fig. 3 to 4, in an embodiment of the secondary battery 100 of the present utility model, the inner edge of the first cover 141 includes a second concave portion 1414, the shape of the second concave portion 1414 may correspond to the second cover 142, for example, when the outer contour of the second cover 142 is circular, the projection of the outer contour of the second concave portion 1414 may be circular, and the shape of the second concave portion 1414 may not correspond to the second cover 142, for example, when the outer contour of the second cover 142 is circular, the second concave portion 1414 may be square to accommodate the second cover 142. The depth of the second recess 1414 is such that the second cover plate 142 is at least partially accommodated in the height direction. A through hole 1411 is provided on the bottom wall of the second recess 1414; the second cap plate 142 is at least partially received in the second recess 1414 in the height direction, and preferably, a side of the second cap plate 142 facing away from the electrode assembly 130 does not protrude beyond the second recess 1414. This reduces the area of engagement with the battery tray when the opening 113 is placed downward, and enables stable support.
Referring to fig. 3 to 5, in an embodiment of the secondary battery 100 of the present utility model, the bottom of the second recess 1414 includes a second land 1416, the second land 1416 is integrally connected with the sidewall of the second recess 1414, the second land 1416 is disposed around the through hole 1411, and the second cap plate 142 is mounted on the side of the second land 1416 facing away from the electrode assembly 130 and is sealed and welded to the sidewall or bottom wall of the second recess 1414. The second cover 142 may be welded to the side wall of the second recess 1414 and the second land 1416 in a sealing manner. In an embodiment of the secondary battery 100 according to the present utility model, the width L of the second land 1416 in the radial direction of the secondary battery 100 is 0.2 to 5mm, which is a range that allows the second cap plate 142 to be in a relatively stable fit relationship with the second land 1416. Preferably, in one embodiment of the secondary battery 100 of the present utility model, the width L of the second land 1416 in the radial direction is 0.5 to 3mm, which can be a relatively stable fit as well as a relatively light weight.
Referring to fig. 2 and 7 to 8, in an embodiment of the secondary battery 100 of the present utility model, a first guide structure 145 is provided between the second cap plate 142 and the second recess 1414; a second guide structure 149 is provided between the third cover plate 147 and the first recess 1425. In an embodiment of the secondary battery 100 of the present utility model, the first guide structure 145 and/or the second guide structure 149 includes one or a combination of the following: rounded corners, chamfers or slopes. Referring to fig. 7 to 8, in an embodiment of the secondary battery 100 of the present utility model, the first guide structure 145 includes a first annular inclined surface 1415, the first annular inclined surface 1415 is a part of a conical surface, the first annular inclined surface 1415 surrounds the through hole 1411 and is contracted from a side facing away from the electrode assembly 130 toward the electrode assembly 130, and an inclination angle of the first annular inclined surface 1415 is 95 to 160 ° to ensure quick fit and welding of the second cap plate 142 and the land of the first recess 1425. In an embodiment of the present utility model, the first guiding structure 145 further includes a second annular inclined surface 1423 disposed on the sidewall 112 of the second cover 142, the second annular inclined surface 1423 being a part of the conical surface, the second annular inclined surface 1423 surrounding the outer edge of the second cover 142 and shrinking from the side facing away from the electrode assembly 130 to the side facing the electrode assembly 130. The first annular chamfer 1415 and the second annular chamfer 1423 are coaxially disposed with a gap 146 formed therebetween. The side of the second cap plate 142 facing away from the electrode assembly 130 is provided with a cylindrical section 1422, and the cylindrical section 1422 is connected to the side of the second annular incline 1423 facing away from the electrode assembly 130. Referring to fig. 8 and 16, in this arrangement, when the second cover plate 142 is welded to the first cover plate 141, on one hand, the edge of the second cover plate 142 at the upper portion of the gap 146 is easy to melt quickly, and on the other hand, molten metal material can flow into the gap 146, so that the second solder 1442 between the second cover plate 142 and the first cover plate 141 has higher strength and sealing property. It should be noted that, the position of the second solder 1442 is referred to in fig. 11, but the shape of the second solder 1442 is only shown as an illustration, and the shape of the second solder is not limited to that of the solder, and other suitable solder forms may be selected and are not listed here.
Referring to fig. 3 and 9, in an embodiment of the secondary battery 100 of the present utility model, the second guiding structure 149 includes a third annular inclined surface 1491, the third annular inclined surface 1491 is a part of the conical surface, the third annular inclined surface 1491 surrounds the through hole 1411 and is contracted from the side facing away from the electrode assembly 130 toward the electrode assembly 130, and the inclination angle of the third annular inclined surface 1491 is 95 to 160 ° to ensure the rapid engagement and welding of the third cover 147 with the first land area 1427 of the first recess 1425. In an embodiment of the present utility model, the first guiding structure 145 further includes a fourth annular inclined surface 1492 disposed on the sidewall 112 of the third cover plate 147, the fourth annular inclined surface 1492 being a part of the tapered surface, the fourth annular inclined surface 1492 encircling the outer edge of the third cover plate 147 and being contracted toward the electrode assembly 130 side at an equal angle. Third annular ramp 1491 and fourth annular ramp 1492 are coaxially disposed.
Referring to fig. 2, 9 and 11, in an embodiment of the secondary battery 100 of the present utility model, a recess 148 is formed at a side of the second and third cap plates 142 and 147 facing away from the electrode assembly 130, and the recess 148 corresponds to a fourth solder 1444 of the second and third cap plates 142 and 147. Recess 148 includes a first ring groove 1481 disposed on a side of first recess 1425 facing away from electrode assembly 130 and a second ring groove 1482 disposed on a side of third cover 147 facing away from electrode assembly 130, with an inner edge of first ring groove 1481 in abutting communication with an outer edge of second ring groove 1482 to form recess 148. The fourth weld 1444 of the third cover 147 and the second recess 1414 is located in the recess 148 where the third annular chamfer 1491 mates with the fourth annular chamfer 1492, the recess 148 is configured to store molten metal flowing during welding of the third cover 147 to the second recess 1414, to reduce spatter of metal slag, and because of the recess 148, the fourth weld 1444 is relatively flat and not easily raised above the side of the second cover 142 or the third cover 147 facing away from the electrode assembly 130. In one embodiment of the present utility model, the depth H4 of the first ring groove 1481 is less than the depth H5 of the second ring groove 1482, which is advantageous for guiding the weld fluid progressively deeper between the third cover plate 147 and the second recess 1414. Preferably, the depth H4 of the first ring groove 1481 is 0.1-0.2 mm and the depth H5 of the second ring groove 1482 is 0.15-0.3 mm.
Referring to fig. 2 and 7, the relative positions of the cap plate welding portion 1432 and the electrode assembly 130 and the first cap plate 141 in the height direction of the secondary battery 100 may be various in the present utility model, and in one embodiment of the secondary battery 100 of the present utility model, the cap plate welding portion 1432 is disposed between the first cap plate 141 and the electrode assembly 130 in the height direction of the secondary battery 100, and one side facing away from the electrode assembly 130 is welded to the first cap plate 141. In this way, when the pre-integration of the first cap plate 141 and the first current collecting member 143 is achieved (i.e., the first current collecting member 143 and the first cap plate 141 are welded in advance as one body before the secondary battery is assembled), the cap plate welded portion 1432 and the first cap plate 141 can be welded from the electrode assembly 130 side, and the welded process window can be increased because the first current collecting member 143 has a small wall thickness with respect to the first cap plate 141.
Referring to fig. 7, in an embodiment of the secondary battery 100 of the present utility model, a side surface of the cap plate welding portion 1432 facing away from the first cap plate 141 includes an inner welding 1471. The inner weld 1471 is formed by welding from the cover plate welding portion 1432 side to the first cover plate 141 side. In one embodiment of the secondary battery of the present utility model, since the energy used in the welding is suitable, the molten pool does not penetrate the first cap plate 141 in the welding from the cap plate welding portion 1432 side to the first cap plate 141 side, and thus the surface of the first cap plate 141 on the side facing away from the cap plate welding portion 1432 does not have a weld mark. However, considering that the process window of the prior art welding technique is narrow, in another embodiment, the inner welding 1471 is included on the surface of the cover plate welding portion 1432 facing away from the first cover plate 141, the outer welding 1472 is included on the surface of the first cover plate 141 facing away from the cover plate welding portion 1432, and the projected area of the inner welding 1471 is larger than the projected area of the outer welding 1472 in the height direction of the secondary battery because welding is performed from the side of the cover plate welding portion 1432 to the side of the first cover plate 141.
The type of weld is not limited, and in one embodiment, the inner weld 1471 includes a discrete plurality of welds that are annular and spaced along the edge of the cover plate weld 1432. In another embodiment, the inner weld 1471 includes a linear weld that continuously or intermittently encircles the edge of the cover plate.
Referring to fig. 11 and 12, in an embodiment of the secondary battery 100 of the present utility model, the cover welding portion 1432 is welded to the edge of the through hole 1411, for example, the edge facing the electrode assembly 130 or the edge facing away from the electrode assembly 130, and the tab welding portion 1431 is recessed toward the electrode assembly 130 with respect to the cover welding portion 1432, and is abutted against the first tab 132 and fixed by welding connection. With this arrangement, the first current collecting member 143 can be reduced in size to provide a battery having a light weight, and the layers of the electrode assembly 130 can be maintained in a relatively smooth communication relationship to facilitate electrolyte filling and exhaust between the layers.
Referring to fig. 2 and 13 to 15, in an embodiment of the secondary battery 100 of the present utility model, the case 110 is cylindrical, the first cover plate 141 is annular, the first current collecting member 143 is annular, the inner side of the annular is formed with an opening 1433, the through hole 1411 is coaxially disposed with the first cover plate 141, the first current collecting member 143 and the through hole 1411 are coaxially disposed, the surface of the exposed first current collecting member 143 in the through hole 1411 is an annular plane area surrounding the opening 1433, the tab welding portion 1431 is distributed in the annular plane area, and the edge of the through hole 1411 can have a uniform thermal deformation when the first cover plate 141 is welded with the case 110. Meanwhile, the tab welding parts 1431 are distributed in the annular plane area which is coaxially arranged with the through holes 1411, and compared with the structure that openings, bulges, grooves and the like are formed in the area where the tab welding parts 1431 are located, the welding positioning can be facilitated.
Referring to fig. 15, in an embodiment of the utility model, the outer diameter of the sidewall is D, the tab welding portions 1431 are distributed in the annular region 1434 centered on the center of the end face of the electrode assembly 130, and the inner diameter D2 of the annular region 1434 is greater than or equal to 0.25D and the outer diameter D3 is less than or equal to 0.87D. In view of the specifications of the existing secondary battery, it is preferable that the inner diameter D2 of the annular region 1434 is greater than or equal to 12mm and the outer diameter D3 of the annular region 1434 is less than or equal to 40mm. In this way, when the first current collecting member 143 and the first tab 134 are welded through the through hole 1411 before the second cover plate 142 is mounted, a solder mark, for example, a third solder mark 1443, is formed on the surface of the first current collecting member 143 in the through hole 1411 when the first current collecting member 143 and the first tab 134 are welded in this way, and it should be noted that the third solder mark 1443 is only a schematic representation of the solder mark between the first current collecting member 143 and the first tab 134, and cannot be used for defining the solder mark shape, but other suitable solder mark forms may also be selected, which are not listed herein. Preferably, in consideration of the specifications of the existing cylindrical secondary battery, tab welding portions 1431 are distributed in a circular ring-shaped region having a diameter of 12 to 40mm, and the circular ring-shaped region 1434 is disposed coaxially with the through hole 1411. In the annular region 1434, the tab of the electrode assembly 130 has a relatively thick and uniform thickness, which is advantageous for the welding stability between the tab welding portion 1431 and the first tab 132 and can reduce the thermal influence of the welding heat on the electrode assembly 130. In an embodiment of the secondary battery 100 according to the present utility model, it is preferable that the diameter D4 of the through-hole 1411 is greater than or equal to 0.43D and less than or equal to 0.96D in consideration of the distribution state of the tabs in the electrode assembly 130, and the through-hole 1411 can cover most of the tab welding area within the diameter range.
Referring to fig. 11, in an embodiment of the secondary battery 100 of the present utility model, an explosion-proof structure 1421 is disposed on the second cover 142, and the explosion-proof structure 1421 is used for at least partially opening when the air pressure inside the casing 110 reaches a certain level, so as to release the pressure inside the casing 110. The type of explosion proof structure 1421 is not limited and may be, for example, an explosion proof valve assembly mounted on the second cover plate 142. In one embodiment of the secondary battery 100 of the present utility model, the explosion-proof structure 1421 includes a score provided on the second cap plate 142, and the score is a ring-shaped structure. It should be noted that the annular structure does not limit the score to be in a circular or elliptical shape, and in the present utility model, the score may be considered as an annular structure by connecting the score end to end. Of course, in other embodiments, the scores may not be connected end to end, and may be, for example, a non-annular profile such as a C-shape, a cross-shape, or the like, so long as the scores can be opened when the pressure is greater than the set threshold. So arranged, the score corresponds to the vent panel, and the location of the score is the weaker area of the second cover 142. When the air pressure inside the case 110 exceeds a certain threshold (at least partially opened when the air pressure exceeds a certain threshold can be realized by calculating the intensity of the notch), the air pressure inside the case 110 is discharged from the rupture, so that the explosion phenomenon of the secondary battery from the case is prevented, and the thermal runaway of the module level is caused. In view of the fact that the nicks may damage the nickel plating layer on the surface of the second cover plate 142 and thus rust may easily occur at the nicking position, it is preferable to provide the nicking opening 113 at the side of the second cover plate 142 facing the electrode assembly 130, so that the nicks are located in the closed space in the case 110, contact between the nicks and air is reduced, the rust degree of the nicks may be slowed down, and the service life of the nicks is prolonged.
Although the provision of the scores on the second cover 142 may play a role in explosion protection, referring to fig. 16, in another embodiment of the secondary battery 100 of the present utility model, the scores are not provided on the plate body of the second cover 142, but the explosion protection is achieved by the second welding 1442 between the first cover 141 and the second cover 142, and when the air pressure inside the case 110 exceeds the connection strength of the second welding 1442 at the first cover 141 and the second cover 142, the second welding 1442 at the first cover 141 and the second cover 142 breaks, thereby releasing pressure, which may play an role in explosion protection as well. Of course, the double guarantee of pressure relief of the explosion-proof component can be realized through the two weak positions of the notch and the second welding mark 1442.
Referring to fig. 7, in an embodiment of the secondary battery 100 of the present utility model, the first cap plate 141 includes a protrusion 1412 matched with the opening 113, the protrusion 1412 protrudes toward the electrode assembly 130, the outer edge of the protrusion 1412 is engaged with the sidewall 112, the protrusion 1412 is used for assembly guiding of the first cap plate 141 and the opening 113, and the sidewall 112 of the case 110 is engaged with the first cap plate 141, so that the first cap plate 141 and the opening 113 can be rapidly positioned along the circumferential direction, thereby improving welding efficiency and welding radial position accuracy. The protrusion 1412 may be integrally and continuously provided around the through-hole 1411, or a plurality of independent protrusions 1412 may be provided around the through-hole 1411. Preferably, in an embodiment, the protrusion 1412 may be disposed continuously around the through hole 1411, and the protrusion 1412 is used for blocking the laser light when the first cover plate 141 and the opening 113 are welded. The connection between the protrusion 1412 and the first cap plate 141 is not limited, and the protrusion 1412 may be integrally formed by press molding, or the protrusion 1412 may be obtained by removing a material from the first cap plate 141 by machining, and in one embodiment of the secondary battery 100 of the present utility model, the protrusion 1412 is obtained by press molding, the height H1 of the protrusion 1412 is 0.1 to 5mm, and the radial width M of the protrusion 1412 is 1 to 10mm in the height direction of the secondary battery 100. Preferably, the height H2 of the protrusion 1412 is 0.5-2.5 mm, which can form a stable mating relationship and reduce weight. On a side surface of the first cap plate 141 facing away from the electrode assembly 130, a groove 1418 corresponding to the protrusion 1412 is formed, and a depth H2 of the groove 1418 is 0.1 to 5mm.
Referring to fig. 7, in an embodiment of the secondary battery 100 of the present utility model, the first cover 141 further includes a limiting portion 1413 disposed around the protrusion 1412, and an end surface of the opening 113 abuts against the limiting portion 1413. The first solder 1441 between the first cover 141 and the opening 113 is disposed around the opening 113 and located on a contact surface between the limiting portion 1413 and the end surface. The positioning of the limiting portion 1413 can realize the axial positioning of the first cover plate 141 and the housing 110 on the one hand, and can increase the air tightness of the first welding 1441 between the first cover plate 141 and the side wall 112 of the housing 110 on the other hand.
Referring to fig. 7, 10 and 15, in an embodiment of the secondary battery 100 according to the present utility model, the case 110 has a cylindrical shape, the protrusion 1412 is provided with an annular plane 1417 toward one side of the electrode assembly 130, the annular plane 1417 is coaxially disposed with the first cap plate 141 and the case 110, the cap plate welding portion 1432 is welded to one side of the annular surface facing the electrode assembly 130, and the electrode assembly 130 includes a central through hole 133; the first current collecting member 143 is provided at the middle thereof with an opening 1433, the opening 1433 is circular, the central through hole 133 is also circular, the opening 1433 and the central through hole 133 are coaxially disposed, and the projection of the opening 1433 covers the projection of the central through hole 133 in the height direction of the secondary battery 100. This arrangement can maintain the chambers at both ends of the electrode assembly 130 in smoother communication through the central through-hole 133. Preferably, in order to reduce the impact of the electrolyte on the edge end surface of the opening 1433, the projection of the opening 1433 covers the projection of the injection hole 1424 in the height direction of the secondary battery 100, considering that the pressure is relatively large when the injection hole is used for injecting the electrolyte.
Referring to fig. 7, in an embodiment of the secondary battery 100 of the present utility model, a distance H3 from the end surface of the first tab 132 to the outer surface of the cap assembly 140 is 0.6-4 mm. Due to the structure in the present utility model, it is possible to achieve a better space utilization of the secondary battery 100 in the height direction, and thus it is possible to improve the energy density of the secondary battery 100.
Referring to fig. 18, the present utility model also provides a battery pack 10 including the secondary battery 100 of any one of the above. Referring to fig. 14, in an embodiment of the battery pack 10 of the present utility model, the battery pack 10 includes a case 101, a case cover 102, and a plurality of secondary batteries 100, the plurality of secondary batteries 100 are placed in the case 101 in series or parallel with each other, or a mixture of series and parallel, and the case cover 102 is sealed on the case 101 to protect the plurality of secondary batteries 100. The battery pack 10 may include a battery pack thermal management system, a circuit board, and the like in addition to the secondary battery 100 of the present utility model, and will not be described in detail herein.
Referring to fig. 17, the present utility model further provides an electronic device 1, where the electronic device 1 includes a working portion 11 and the battery pack 10, and the working portion 11 is electrically connected to the battery pack 10 to obtain power support. As an example, in the present embodiment, the electronic device 1 is a vehicle, and the vehicle may be a fuel-oil vehicle, a gas-oil vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended range vehicle, but is not limited thereto. The working section 11 is a vehicle body, and the battery pack 10 is provided at the bottom of the vehicle body and provides electric power support for running of the vehicle or running of electric components in the vehicle. However, in other embodiments, the electronic device may also be a cell phone, portable device, notebook computer, boat, spacecraft, electric toy, electric tool, etc. Spacecraft including airplanes, rockets, space planes, spacecraft, and the like; the working part may be a unit part capable of taking the electric power of the battery pack and making a corresponding work, such as a blade rotating unit of a fan, a dust suction working unit of a dust collector, 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 application does not particularly limit the electronic device.
In the secondary battery 100 of the present utility model, the outer edge of the first cap plate 141 is welded to the sidewall 112 and seals the opening 113, the current collecting member 143 is welded to the first cap plate 141, and there is no connection between the current collecting member 143 and the sidewall 112 of the case 110, so that the technical problem that the current collecting member 143 is welded to the sidewall 112 of the case 110 and is easily extruded during the sealing process to cause connection failure can be improved. Meanwhile, the sealed package of the secondary battery 100 can be realized without the need of the rolling groove and the heading process on the shell 110, the process is simplified, the assembly efficiency is higher, and the height of the rolling groove can be saved, so that the space utilization rate of the secondary battery 100 is improved. And in the secondary battery 100 of the present utility model, the electrical connection of the first current collecting member 143 and the case 110 can be further achieved through the conductive connection of the first current collecting member 143 and the first cap plate 141, so that the structure is also advantageous in achieving pre-assembly of the first cap plate 141 and the first current collecting member 143 outside the case 110, reducing assembly steps, and simultaneously reducing damage to the electrode assembly 130 when the first current collecting member 143 and the first cap plate 141 are welded facing the electrode assembly 130. In addition, the secondary battery 100 of the present utility model can avoid the problem that the first current collecting member 143 is difficult to be welded with the case 110 due to the rolling groove, and the first cover plate 141 has a larger degree of freedom in both structure and thickness than the first current collecting member 143, so that the welding process window can be increased when the case 110 is welded with the first cover plate 141, and the problems of welding leakage and welding penetration in the welding process of the first current collecting member 143 and the case 110 can be reduced, and the foreign matters entering the case 110 can be reduced. In addition, in the present utility model, the second cover plate 142 and the third cover plate 147 are combined to realize the sealing of the through hole 1411 on the first cover plate 141, and the liquid injection can be performed from the liquid injection hole 1424 after the second cover plate 142 and the first cover plate 141 are welded, so that the thermal influence of a larger welding area and a longer welding time on the electric liquid connection can be prevented when the second cover plate 142 and the first cover plate 141 are welded. 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 (16)

1. A secondary battery, characterized by comprising:
a housing comprising an end wall and a side wall surrounding the end wall, the side wall having an opening formed at an end facing away from the end wall;
a terminal mounted hermetically and insulatively through the end wall;
an electrode assembly housed in the case, the electrode assembly including a first tab facing the opening and a second tab facing the end wall, the second tab being electrically connected to the terminal;
the first current collecting member is arranged at one end of the electrode assembly facing the opening, and the first current collecting member is connected with the first tab in a welding way;
the cover plate assembly comprises a first cover plate, a second cover plate and a third cover plate; the first cover plate is covered on the opening and is welded with the side wall, the first cover plate is welded with the first current collecting member, the first cover plate comprises a through hole, the second cover plate is welded on the first cover plate and seals the through hole, and the second cover plate comprises a liquid injection hole; a third cover plate is fixed on the second
And the cover plate is used for sealing the liquid injection hole.
2. The secondary battery according to claim 1, wherein the first current collecting member includes a cap plate welding portion and a tab welding portion, the cap plate welding portion being welded to the first cap plate, the tab welding portion being welded to the first tab.
3. The secondary battery according to claim 2, wherein a projection of the through hole on the first current collecting member covers the tab welding portion in a height direction of the secondary battery.
4. The secondary battery according to claim 3, wherein a thickened portion is provided on a side of the second cap plate adjacent to the electrode assembly, and the liquid injection hole is provided on the thickened portion and penetrates in a thickness direction of the thickened portion.
5. The secondary battery according to claim 3, wherein a side of the third cap plate facing the liquid injection hole is provided with a relief portion recessed from a side near the electrode assembly toward a side facing away from the electrode assembly.
6. The secondary battery according to claim 3, wherein the second cover plate is provided with a first recess, the liquid filling hole is provided in the first recess, and the third cover plate is at least partially accommodated in the first recess.
7. The secondary battery according to claim 6, wherein a side of the third cap plate facing away from the electrode assembly does not protrude beyond the first recess.
8. The secondary battery according to claim 6, wherein the bottom of the first recess includes a first land portion disposed around the liquid injection hole, and the third cap plate is mounted on a side of the first land portion facing away from the electrode assembly and is welded to the first land portion.
9. The secondary battery according to claim 3, wherein the first cover plate is provided with a second recess, the through hole is provided in the second recess, and the second cover plate is at least partially accommodated in the second recess.
10. The secondary battery according to claim 9, wherein a side of the second cap plate facing away from the electrode assembly does not protrude beyond the second recess.
11. The secondary battery according to claim 10, wherein the bottom of the second recess includes a second land portion disposed around the through hole, and the second cap plate is mounted on a side of the second land portion facing away from the electrode assembly and welded to the second land portion.
12. The secondary battery according to claim 3, wherein the cap plate welding portion is disposed between the first cap plate and the electrode assembly, and a side facing away from the electrode assembly is welded to the first cap plate.
13. The secondary battery according to claim 1, wherein the electrode assembly includes a central through hole, and the first current collecting member is provided at a central portion thereof with an opening, a projection of which covers a projection of the central through hole in a height direction of the secondary battery.
14. The secondary battery according to claim 13, wherein a projection of the opening covers a projection of the pouring hole in a height direction of the secondary battery.
15. A battery pack comprising the secondary battery according to any one of claims 1 to 14.
16. An electronic device comprising the battery pack of claim 15.
CN202321976982.9U 2023-07-25 2023-07-25 Secondary battery, battery pack, and electronic device Active CN220382277U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202321976982.9U CN220382277U (en) 2023-07-25 2023-07-25 Secondary battery, battery pack, and electronic device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202321976982.9U CN220382277U (en) 2023-07-25 2023-07-25 Secondary battery, battery pack, and electronic device

Publications (1)

Publication Number Publication Date
CN220382277U true CN220382277U (en) 2024-01-23

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202321976982.9U Active CN220382277U (en) 2023-07-25 2023-07-25 Secondary battery, battery pack, and electronic device

Country Status (1)

Country Link
CN (1) CN220382277U (en)

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