CN220627968U - Secondary battery, battery pack, and electricity using device - Google Patents

Abstract

The utility model provides a secondary battery, a battery pack and an electric device, wherein the secondary battery comprises: a case, an electrode assembly, a current collecting member, and a cap plate assembly. A housing end wall and a side wall having an opening; the terminal is installed through the end wall; the electrode assembly includes a tab facing the opening; the current collecting component is welded with the tab; the cover plate assembly comprises a first cover plate and a second cover plate; the first cover plate covers the opening and is welded with the side wall, the first cover plate is welded with the current collecting member, the first cover plate comprises a first area and a second area, the first area is welded with the current collecting member, a liquid injection hole penetrating through the second area is arranged in the second area, and the first area and the second area have height differences along the height direction of the secondary battery; the second cover plate is welded with the first cover plate and seals the liquid injection hole, and the utility model can solve the problem that welding slag falls into the electrode assembly when the current collecting component is welded on the cover plate.

Description

Secondary battery, battery pack, and electricity using device

Technical Field

The utility model relates to the technical field of batteries, in particular to a secondary battery, a battery pack and an electric device.

Background

At present, a large cylinder is more and more favored by various cart enterprises because of 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 current collecting member at the opening side of the case, and the current collecting member is welded to the side wall of the case to realize electrification of the case. In the subsequent battery sealing process, the side wall of the shell is subjected to larger extrusion stress, so that the connection failure of the current collecting member and the shell is risked.

In order to solve the problems, a cover plate is arranged between the current collecting member and the shell to realize the electric connection between the current collecting member and the shell, the periphery of the cover plate is welded with the side wall, and the lower surface of the cover plate is welded with the current collecting member; however, welding slag can occur while the cover plate is welded with the current collecting member, and if the welding slag falls into the electrode assembly through the liquid injection hole, a great potential safety hazard exists.

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 electric device, which can improve the problem that welding slag falls into an electrode assembly when a current collecting member is welded on a cap plate.

To achieve the above and other related objects, the present utility model provides a secondary battery comprising: a case, a terminal, an electrode assembly, a current collecting member, and a cap plate assembly. The shell 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; the terminal is installed through the end wall in a sealing and insulating manner; an electrode assembly accommodated in the case, the electrode assembly including a tab facing the opening; the current collecting component is arranged at one end of the electrode assembly facing the opening and is welded with the electrode lug; the cover plate assembly comprises a first cover plate and a second cover plate; the first cover plate covers the opening and is welded with the side wall, the first cover plate is welded with the current collecting member, the first cover plate comprises a first area and a second area, the first area is welded with the current collecting member, a liquid injection hole penetrating through the second area is arranged in the second area, and the first area and the second area have height differences along the height direction of the secondary battery; the second cover plate is welded with the first cover plate and seals the liquid injection hole.

In an embodiment of the secondary battery of the present utility model, the current collecting member includes a cap plate welding portion and a tab welding portion, the cap plate welding portion being welded to the first region, the tab welding portion being welded to the tab.

In an embodiment of the secondary battery of the present utility model, the first region is disposed around the second region, and a distance from a side of the first region facing away from the electrode assembly to the electrode assembly is smaller than a distance from a side of the second region facing away from the electrode assembly to the electrode assembly.

In an embodiment of the secondary battery of the present utility model, the thickness of the welding portion of the cover plate is greater than the thickness of the welding portion of the tab, and the welding portion of the cover plate is provided with a first opening, and the first opening is communicated with the liquid injection hole.

In an embodiment of the secondary battery of the present utility model, the second region is disposed around the first region, and a distance from a side of the first region facing away from the electrode assembly to the electrode assembly is greater than a distance from a side of the second region facing away from the electrode assembly to the electrode assembly.

In an embodiment of the secondary battery of the present utility model, the liquid injection holes are provided in plurality, and the plurality of liquid injection holes are provided along the circumferential direction of the second region.

In an embodiment of the secondary battery of the present utility model, the cover plate welding portion protrudes toward the first area to form a first protrusion, and the first protrusion is welded to a side of the first area facing away from the second cover plate.

In an embodiment of the secondary battery of the present utility model, a side of the first region near the first boss is provided with a first recess, and at least a portion of the first boss is accommodated in the first recess.

In an embodiment of the secondary battery of the present utility model, the current collecting member is provided with a second opening, the second opening is disposed beside the first pillar, and the second opening is communicated with the liquid injection hole.

In an embodiment of the secondary battery of the present utility model, a welding hole is disposed on the first area, the welding hole penetrates through the first area along the thickness direction of the first area, the welding portion of the cover plate protrudes toward the first area to form a second protruding column, and the second protruding column is adapted to the welding hole and is welded and connected.

In an embodiment of the secondary battery of the present utility model, the first cover plate is provided with a second recess, the first region and the second region are disposed in the second recess, and the second cover plate is at least partially accommodated in the second recess and covers at least the first region and the welding stamp of the current collecting member.

In one embodiment of the secondary battery of the present utility model, the bottom of the second recess includes a land, and the second cap plate is mounted on a side of the land facing away from the electrode assembly and is welded to the land.

The present utility model also provides a battery pack including the secondary battery of any one of the above.

The utility model also provides an electric device which comprises the battery pack.

In the secondary battery, the first cover plate comprises the first area and the second area, the first area and the second area are provided with the height difference along the height direction of the secondary battery, the first area is connected with the current collecting member in a welding way, and the second area is provided with the liquid injection hole, so that the separation of the welding area and the liquid injection hole along the height direction can be realized through the height difference between the first area and the second area, the contact between electrolyte and welding slag can be reduced in the liquid injection process, the overflowed electrolyte is prevented from carrying the welding slag to flow back into the liquid injection hole, and the risk of failure of the battery core 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 a partial enlarged view of the region I of fig. 1 in an embodiment of the secondary battery according to the present utility model;

fig. 3 is a partial sectional view of a first cap plate and a first current collecting member in an embodiment of a secondary battery according to the present utility model;

fig. 4 is a partial enlarged view of the region I of fig. 1 in another embodiment of the secondary battery according to the present utility model;

fig. 5 is a partial sectional view of a first cap plate and a first current collecting member in another embodiment of a secondary battery according to the present utility model;

fig. 6 is a partial enlarged view of the region I of fig. 1 in a further embodiment of the secondary battery according to the present utility model;

fig. 7 is a partial sectional view of a first cap plate and a first current collecting member in still another embodiment of a secondary battery according to the present utility model;

FIG. 8 is a schematic diagram of an embodiment of an electrical device according to the present utility model;

fig. 9 is a schematic view of an embodiment of a battery pack according to the present utility model.

Description of element reference numerals

1. An electric device; 10. a battery pack; 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; 140. a first current collecting member; 141. a cover plate welding part; 142. a tab welding part; 143. a first opening; 144. a first post; 145. a second post; 146. a second opening; 150. a cover plate assembly; 151. a first cover plate; 1511. a first region; 1512. a second region; 1513. a first concave portion; 1514. a liquid injection hole; 15141. a first arcuate wall; 15142. a second arcuate wall; 15143. a first connecting wall body; 15144. a second connecting wall; 1515. a second concave portion; 1516. welding holes; 1517. a land area; 152. a second cover plate; 160. and a second current collecting member.

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 identical to the methods, apparatus, or materials of the embodiments of the 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 9, the present utility model provides a secondary battery 100, and a battery pack 10 and an electric device 1 including the secondary battery 100, the secondary battery 100 including: the case 110, the terminal 120, the electrode assembly 130, the current collecting member, and the cap plate assembly 150. The cap assembly 150 includes a first cap plate 151, the first cap plate 151 including a first region 1511 and a second region 1512, the first region 1511 being welded to the current collecting member, the second region 1512 having a liquid injection hole 1514 penetrating the second region 1512, the first region 1511 and the second region 1512 having a height difference along a height direction of the secondary battery 100; through this difference in height realize that welded area and annotate liquid hole 1514 follow the isolation of direction of height, can reduce the contact of electrolyte and welding slag at annotating the liquid in-process, prevent that the electrolyte that spills over from carrying the welding slag back flow to annotating in the liquid hole 1514, can reduce the risk that the electric core became invalid.

Referring to fig. 1, 2, 4 and 6, 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 various ways, such as integrally stamping, integrally casting, or separately welding, as long as a stable sealing and electrical connection relationship can be formed. The side wall 112 may be, but not limited to, a cylindrical or prismatic shape, or may be formed along 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 formed in a cylindrical shape 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, 2, 4 and 6, 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 an active material, and the uncoated region is wound to form a positive electrode tab of the electrode assembly 130. 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 130. 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. In the present utility model, the electrode assembly 130 includes two tabs facing the end wall 111 and facing the opening 113, for convenience of distinction, the tab facing the opening 113 is named as a first tab 132, the tab facing the end wall 111 is named as a second tab 131, the second tab 131 may be a positive tab or a negative tab, the first tab 132 is opposite to the second tab 131 in electrical property, when the second tab 131 is a positive tab, the first tab 132 is a negative tab, when the second tab 131 is a negative tab, the first tab 132 is a positive tab, both tabs are connected with current collecting members, and for convenience of distinction, the tab is named as a first current collecting member 140 connected with the first tab 132, the tab 131 is named as a second current collecting member 160 connected with the second tab 131, the second tab 131 is electrically connected with the terminal 120 through the second current collecting member 160, and the first current collecting member 140 is disposed at one end of the electrode assembly 130 facing the opening 113 and is welded with 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, a terminal 120 is mounted on an end wall 111 of a housing 110, and 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 160, one end of the terminal 120 facing the opening 113 is welded to the second current collecting member 160, and one side of the second current collecting member 160 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 aluminum having a series of 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. 1, in the present utility model, the materials of the first current collecting member 140 and the second current collecting member 160 are selected according to the polarity of the tab connected thereto, for example, if the second current collecting member 160 is connected to the positive electrode tab, the second current collecting member 160 may be made of aluminum metal, and the material of the first current collecting member 140 and the negative electrode tab may be made of copper metal opposite to the second current collecting member 160. If the second current collecting member 160 is connected to the negative electrode tab, the second current collecting member 160 may be made of copper, and in this case, the first current collecting member 140 is connected to the positive electrode tab opposite to the second current collecting member 160, and the first current collecting member 140 may be made of aluminum. The shapes and structures of the second current collecting member 160 and the first current collecting member 140 are not limited either, and are suitable in order to enable a stable and reliable electrical connection relationship.

Referring to fig. 1-7, the cover assembly 150 is sealed to the opening 113. The cap plate assembly 150 includes a first cap plate 151 and a second cap plate 152. The outer edge of the first cap plate 151 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 method may be a welding method capable of sealing a welding position, for example, a welding head is welded in a direction perpendicular to the side wall 112 and is moved relative to the secondary battery 100 in the circumferential direction during the welding process, so that a first welding mark is formed on the side wall 112; 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 relative to the secondary battery 100 along the shape of the outer edge of the first cap plate 151 during welding, so that the outer edge of the first cap plate 151 forms a closed loop first weld mark at a position where the outer edge of the first cap plate 151 contacts the end surface of the side wall 112. The first cap plate 151 includes a first region 1511 and a second region 1512, the shape of the first region 1511 and the second region 1512 is not limited, the shape of the first region 1511 may be a circular shape, an elliptical shape, a polygonal shape, or the like, and the shape of the second region 1512 may be a circular shape, an elliptical shape, a polygonal shape, or the like, and the type having a closed contour, the relative position between the first region 1511 and the second region 1512 is not limited, the first region 1511 may surround the second region 1512, the second region 1512 surrounds the first region 1511, the first region 1511 partially surrounds the second region 1512 or the second region 1512 partially surrounds the first region 1511, the first region 1511 and the second region 1512 may be distributed independently of each other, and there is no interference between the first region 1511 and the second region 1512 as long as the height difference between the first region 1511 and the second region 1512 is ensured in the height direction of the secondary battery 100, the first region 1511 may be higher than the second region 1512, the second region 1512 may be higher than the first region 1512, and the required height of the secondary battery assembly 151is further apart from the electrode 130. The secondary battery 100 realizes the isolation of the solder printing region and the liquid injection hole 1514 along the height direction through the height difference between the first region 1511 and the second region 1512, can reduce the contact between electrolyte and welding slag in the liquid injection process, prevent overflowed electrolyte from carrying the welding slag to flow back into the liquid injection hole 1514, can reduce the risk of failure of a battery core, and can realize the welding connection of the first region 1511 and the first current collecting member 140, so long as the stable conductive connection of the first cover plate 151 and the first current collecting member 140 can be realized, and the welding position and the welding shape of the first cover plate 151 and the first current collecting member 140 are not limited. The second region 1512 is provided with a liquid injection hole 1514 penetrating the second region 1512, and the liquid injection hole 1514 may be provided at any position on the second region 1512, and the shape and size of the liquid injection hole 1514 are not limited, and preferably, are capable of matching with an electrolyte injection device.

Referring to fig. 1 to 7, the second cover plate 152 is fixed to the first cover plate 151 and covers the liquid injection hole 1514; as long as the liquid injection hole 1514 can be effectively sealed, there are various ways in which the second cover plate 152 seals the liquid injection hole 1514, for example, the second cover plate 152 is welded on the first cover plate 151 and seals the liquid injection hole 1514, or a structural adhesive having a certain strength and not corroded by the electrolyte is used to realize sealing adhesion between the second cover plate 152 and the first cover plate 151, etc. The shape of the second cover plate 152 may correspond to the shape of the liquid injection hole 1514, for example, the second cover plate 152 may be circular when the liquid injection hole 1514 is circular, and the second cover plate 152 may be square when the liquid injection hole 1514 is square. The shape of the second cover plate 152 may not correspond to the shape of the liquid injection hole 1514, for example, when the liquid injection hole 1514 is circular, the second cover plate 152 may be square to cover the liquid injection hole 1514, and when the liquid injection hole 1514 is square, the second cover plate 152 may be circular to cover the liquid injection hole 1514.

In order to further reduce the probability of the slag in the welding area entering the liquid injection hole 1514 during liquid injection, the surface of the welding area where the welding operation is completed may be subjected to a glue application operation. This can fix the slag of the welding area on the surface of the welding area by using the viscosity of the glue, thereby preventing the slag from falling into the liquid injection hole 1514 during liquid injection.

Referring to fig. 1 to 7, in an embodiment of the secondary battery 100 of the present utility model, the first current collecting member 140 includes a cap plate welding portion 141 and a tab welding portion 142, the shape of the cap plate welding portion 141, the shape of the tab welding portion 142, and the relative positions of the cap plate welding portion 141 and the tab welding portion 142 are not limited, and the cap plate welding portion 141 is welded to the first cap plate 151 and the tab welding portion 142 is welded to the first tab 132.

Referring to fig. 1 to 3, in an embodiment of the secondary battery 100 of the present utility model, the first region 1511 is disposed around the second region 1512, the shapes of the first region 1511 and the second region 1512 are not limited, preferably, the second region 1512 is disposed in a circular shape coaxial with the center of the first cover plate 151, the first region 1511 is in a circular ring shape surrounding the circular shape and coaxial with the circular shape, the distance a from the side of the first region 1511 facing away from the electrode assembly 130 to the electrode assembly 130 is smaller than the distance b from the side of the second region 1512 facing away from the electrode assembly 130 to the electrode assembly 130, the arrangement is such that a concave portion is formed in the first cover plate 151 along the height direction of the secondary battery 100 relative to the second region 1512, the welding region of the cover plate welding portion 141 and the first cover plate 151 is located in the first region 1511, the welding slag generated by welding is retained in the concave portion, the arrangement reduces the contact between the electrolyte and the slag during the liquid filling process, prevents the overflow of the electrolyte from carrying the slag back into the liquid filling hole 4, the risk of the cell core slag can be reduced, the risk of failure can be reduced, the electrolyte can be easily accumulated in the concave portion 1514 is not matched with the second region 1512 in any of the second region 1512, and the second region 1512 is disposed in the shape of the concave region 1512 is located in the shape of the concave region 1512, and the hole can be better arranged in the middle of the hole can be cleaned. In this embodiment, the liquid injection hole 1514 is a circular hole, and the diameter D1 is 3-6 mm, so that the device has a large versatility in the diameter range, and realizes the matching with a plurality of liquid injection devices. Of course, in other embodiments, the fill port 1514 may be of other suitable dimensions.

Referring to fig. 1 to 3, in an embodiment of the secondary battery 100 of the present utility model, the thickness of the cover welding portion 141 is greater than the thickness of the tab welding portion 142, and the thickness of the cover welding portion 141 includes, but is not limited to, integral connection, additive welding, additive bonding, etc., a first opening 143 is provided on the cover welding portion 141, and the first opening 143 is communicated with a filling hole 1514, the shape of the first opening 143 is not limited, so long as the first opening is communicated with the filling hole 1514, and the electrolyte is conveniently filled from the first opening 143, preferably, the orthographic projection of the filling hole 1514 along the height direction of the secondary battery 100 is inside the orthographic projection of the first opening 143. The thickened arrangement of the cover plate welding portion 141 can strengthen the strength of the first current collecting member 140 on one hand, and can avoid hidden danger of penetration due to the fact that the cover plate welding portion 141 is too thin on the other hand, a thicker hole wall is formed around the first hole 143, so that before the second cover plate 152 is installed, the liquid injection hole 1514 can be plugged by adopting sealing nails according to requirements, foreign matters are prevented from entering, and electrolyte is prevented from volatilizing.

Referring to fig. 1, 4 and 5, in another embodiment of the secondary battery 100 of the present utility model, the second region 1512 is disposed around the first region 1511, the shapes of the first region 1511 and the second region 1512 are not limited, preferably, the first region 1511 is disposed in a circular shape coaxial with the center of the first cover plate 151, the second region 1512 is in a circular shape coaxial with the circular shape around the above-mentioned circular shape, the distance a from the side of the first region 1511 facing away from the electrode assembly 130 to the electrode assembly 130 is greater than the distance b from the side of the second region 1512 facing away from the electrode assembly 130 to the electrode assembly 130 in the height direction of the secondary battery 100, the arrangement is such that the second region 1512 forms a recess on the first cover plate 151 relative to the first region 1511, and the solder mask 1514 is disposed at any position on the second region 1512, the solder mask welding portion 141 and the solder mask region of the first cover plate 151 are disposed in the first region 1, the electrolyte overflowed during the solder mask filling is contained in the second region 1511, the solder mask can be separated from the solder mask residue region 1514 in the height direction, and the solder mask can be prevented from being leaked from the solder mask residue region and the solder mask can be carried in the solder mask region and the solder mask can be reduced in the height direction.

Referring to fig. 1, 4 and 5, in an embodiment of the secondary battery 100 of the present utility model, a plurality of injection holes 1514 are provided, and a plurality of injection holes 1514 are provided along the circumference of the second region 1512, preferably, in an embodiment, 2 injection holes 1514 are provided, and are uniformly distributed along the circumference of the second region 1512, and the shape and size of the injection holes 1514 are not limited, preferably, so as to be able to match with the electrolyte injection device. In this embodiment, the liquid injection hole 1514 includes a first arc-shaped wall 15141, a second arc-shaped wall 15142, a first connecting wall 15143 and a second connecting wall 15144, the first arc-shaped wall 15141 and the second arc-shaped wall 15142 are coaxially disposed with the center of the first cover plate 151 as the center of the circle, the first connecting wall 15143 and the second connecting wall 15144 are disposed at two ends of the first arc-shaped wall 15141 and the second arc-shaped wall 15142 respectively, and two sides of the first connecting wall 15142 are connected with the first arc-shaped wall 15141 and the second arc-shaped wall 15142 respectively, the diameter of the first arc-shaped wall 15141 is in the range of the diameter of the second arc-shaped wall 15142, and because the number of openings of the liquid injection hole 1514 affects the strength of the first cover plate 151, the arrangement ensures the strength of the first cover plate 151, and simultaneously improves the cross-sectional area of the liquid injection hole 1514, and the liquid injection hole 1514 is located at the position of the electrode lug stack layer stack, so that the electrolyte injected into the electrode assembly 130 is more uniform.

Referring to fig. 1, 4 and 5, in an embodiment of the secondary battery 100 of the present utility model, the cover welding portion 141 protrudes toward the first region 1511 to form a first pillar 144, the cross-sectional shape of the first pillar 144 is not limited, and may be circular, elliptical, polygonal, etc., the size of the first pillar 144 is not limited, the first pillar 144 is formed by a method including but not limited to integral connection, additive welding, additive bonding, etc., and the first pillar 144 is welded to a side of the first region 1511 facing away from the second cover 152.

Referring to fig. 1, 4 and 5, in an embodiment of the secondary battery 100 of the present utility model, a first recess 1513 is disposed on a side of the first region 1511 near the first pillar 144, at least a portion of the first pillar 144 is accommodated in the first recess 1513, the cross-sectional shape of the first recess 1513 is not limited, as long as at least a portion of the first pillar 144 can be accommodated in the first recess 1513, preferably, the first pillar 144 is cylindrical, and the first recess 1513 also adopts a cylindrical blind hole adapted to the first pillar 144, which can realize positioning of a relative position between the first cover plate 151 and the current collecting member, and on the other hand, can limit the degree of freedom of the first cover plate 151 in a horizontal direction when performing a welding process of an outer edge of the first cover plate 151 and the side wall 112 of the opening 113, and can reduce difficulty of a welding process and improve welding quality.

Referring to fig. 1, 4 and 5, in an embodiment of the secondary battery 100 of the present utility model, the first current collecting member 140 is provided with a second opening 146, the second opening 146 is disposed beside the first pillar 144, and the second opening 146 is communicated with the filling hole 1514, the shape of the second opening 146 is not limited, so long as the second opening 146 is communicated with the filling hole 1514, and the electrolyte is conveniently filled from the second opening 146, preferably, the second opening 146 is projected in the orthographic projection of the filling hole 1514 along the height direction of the secondary battery 100, which can improve the electrolyte filling efficiency.

Referring to fig. 1, 6 and 7, in still another embodiment of the secondary battery 100 of the present utility model, a welding hole 1516 is disposed on the first region 1511, the welding hole 1516 penetrates through the first region 1511 along the thickness direction, the cover plate welding portion 141 protrudes toward the first region 1511 to form a second protrusion 145, the second protrusion 145 is adapted to the welding hole 1516, and is welded, the cross-sectional shapes of the welding hole 1516 and the second protrusion 145 are not limited, and may be circular, elliptical or polygonal, etc., the second protrusion 145 is matched with the welding hole 1516, so that the welding head of the second protrusion 145 and the welding hole 1516 moves circumferentially along the outer edge of the mating surface of the second protrusion 145 and the welding hole 1516, the welding mark is formed on the outer edge of the mating surface of the second protrusion 145 and the welding hole 1516, preferably, the cross-sections of the second protrusion 145 and the welding hole 1516 are both selected to be circular, the arrangement can realize the positioning of the relative position between the first cover plate 151 and the current collecting member on the one hand, and on the other hand, when the welding procedure of the outer edge of the first cover plate 151 and the side wall 112 of the opening 113 is carried out, the effect of limiting the degree of freedom of the first cover plate 151 in the horizontal direction can be achieved, and the welding position of the welded piece is exposed outside, various welding modes can be adopted, such as laser welding, brazing, argon arc welding, ultrasonic welding and the like, so that the welding process window is increased, the welding quality is improved, the relative position of the second convex column 145 and the welding hole 1516 is not limited, the second convex column 145 can protrude from the welding hole 1516, the second convex column 145 can be concave into the welding hole 1516, and can be flush with the welding hole 1516, preferably, the second convex column 145 is slightly concave into the welding hole 1516, the arrangement can form a groove in the welding hole 1516 to accommodate welding slag generated in the welding process, the spilled electrolyte is prevented from carrying solder slag back into the electrode assembly 130.

Referring to fig. 2 to 7, in an embodiment of the secondary battery 100 of the present utility model, the inner edge of the first cover 151 includes a second concave portion 1515, the shape of the second concave portion 1515 may correspond to the second cover 152, for example, when the outer contour of the second cover 152 is circular, the projection of the outer contour of the second concave portion 1515 may be circular, and the shape of the second concave portion 1515 may not correspond to the second cover 152, for example, when the outer contour of the second cover 152 is circular, the second concave portion 1515 may be square to accommodate the second cover 152. The depth of the second recess 1515 is such that the second cover plate 152 is at least partially accommodated in the height direction. The second cap plate 152 is at least partially received in the second recess 1515 in the height direction, and preferably, a side of the second cap plate 152 facing away from the electrode assembly 130 does not protrude beyond the second recess 1515. 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 7, in an embodiment of the secondary battery 100 of the present utility model, the bottom of the second recess 1515 includes a platform region 1517, the platform region 1517 is integrally connected with the sidewall 112 of the second recess 1515, and the second cover plate 152 is mounted on the side of the platform region 1517 facing away from the electrode assembly 130 and welded to the platform region 1517 of the second recess 1515, and it should be noted that the second cover plate 152 may be welded to both the sidewall 112 and the bottom wall of the second recess 1515 in a sealing manner.

Referring to fig. 2 to 7, in an embodiment of the secondary battery 100 of the present utility model, the second cover plate 152 seals the liquid injection hole 1514 and the welding area of the first area 1511 and the current collecting member, and the arrangement ensures that the liquid injection hole 1514 is sealed and the welding area is sealed, so that on one hand, the naked appearance of the welding is prevented from being affected, on the other hand, the welding quality is prevented from being affected due to the fact that the welding is oxidized, on the other hand, two positions of the liquid injection hole 1514 and the welding area can be sealed by one second cover plate 152, the welding process is simplified, and the assembly efficiency is improved.

Referring to fig. 9, the present utility model also provides a battery pack 10, the battery pack 10 including the secondary battery 100 of any one of the above. 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 being placed in the case 101 in series or parallel with each other, or a mixture of series and parallel, the case cover 102 being covered on the case 101 to protect the plurality of secondary batteries 100. It should be noted that, the battery pack 10 may also include a thermal management system, a circuit board, etc. of the battery pack 10 in addition to the secondary battery 100 of the present utility model, and the battery pack 10 may be a battery module, a battery pack, an energy storage electric cabinet, etc.; and will not be described in detail herein.

Referring to fig. 8, the present utility model further provides an electric device 1, where the electric 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 electric energy support. As an example, in the present embodiment, the electric 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 power consumption device 1 may be a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool, or the like. Spacecraft including airplanes, rockets, space planes, spacecraft, and the like; the working unit 11 may be a unit member capable of taking electric power of the battery pack 10 and making a corresponding work, such as a blade rotation unit of a fan, a dust suction working unit of a dust collector, or 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 application does not particularly limit the above-described power consumption device 1.

In the secondary battery 100 of the present utility model, the first cap plate 151 includes a first region 1511 and a second region 1512, a distance from a side of the first region 1511 away from the electrode assembly 130 to the electrode assembly 130 is a distance one, and a distance from a side of the second region 1512 away from the electrode assembly 130 to the electrode assembly 130 is a distance two, which are unequal in a height direction of the secondary battery 100; the first region 1511 is welded to the current collecting member, and the second region 1512 is provided with a liquid injection hole 1514; thus, the isolation between the welding area and the liquid injection hole 1514 along the height direction can be realized through the height difference between the first area 1511 and the second area 1512, the contact between the electrolyte and the welding slag can be reduced in the liquid injection process, the overflowed electrolyte is prevented from carrying the welding slag to flow back into the liquid injection hole 1514, and the risk of failure of the battery cell can be reduced. 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 (13)

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;

an electrode assembly accommodated in the case, the electrode assembly including a tab facing the opening;

a current collecting member disposed at one end of the electrode assembly facing the opening, the current collecting member being electrically connected with the tab;

the cover plate assembly comprises a first cover plate and a second cover plate; the first cover plate covers the opening and is welded with the side wall, the first cover plate comprises a first area and a second area, the first area is welded with the current collecting member, a liquid injection hole penetrating through the second area is arranged in the second area, and the first area and the second area have height differences along the height direction of the secondary battery; the second cover plate is connected with the first cover plate in a welding way and seals the liquid injection hole.

2. The secondary battery according to claim 1, wherein the current collecting member includes a cap plate welding portion and a tab welding portion, the cap plate welding portion being welded to the first region, the tab welding portion being welded to the tab.

3. The secondary battery according to claim 2, wherein the first region is disposed around the second region, and a distance from a side of the first region facing away from the electrode assembly to the electrode assembly is smaller than a distance from a side of the second region facing away from the electrode assembly to the electrode assembly.

4. The secondary battery according to claim 3, wherein the thickness of the cap plate welding portion is greater than the thickness of the tab welding portion, a first opening is provided in the cap plate welding portion, and the first opening communicates with the liquid filling hole.

5. The secondary battery according to claim 2, wherein the second region is disposed around the first region, and a distance from a side of the first region facing away from the electrode assembly to the electrode assembly is greater than a distance from a side of the second region facing away from the electrode assembly to the electrode assembly.

6. The secondary battery according to claim 5, wherein a plurality of the liquid injection holes are provided, and a plurality of the liquid injection holes are provided along the circumferential direction of the second region.

7. The secondary battery according to claim 6, wherein the cap plate welding portion protrudes toward the first region to form a first boss, and the first boss is welded to a side of the first region facing away from the second cap plate.

8. The secondary battery according to claim 7, wherein a side of the first region near the first boss is provided with a first recess, and at least a portion of the first boss is accommodated in the first recess.

9. The secondary battery according to claim 8, wherein the current collecting member is provided with a second opening provided beside the first boss, and the second opening communicates with the liquid injecting hole.

10. The secondary battery according to claim 6, wherein a welding hole is provided in the first region, and the welding hole penetrates in a thickness direction of the first region, and the cover plate welding portion protrudes toward the first region to form a second boss, which is adapted to the welding hole and is welded to the welding hole.

11. The secondary battery according to any one of claims 1 to 10, wherein a second recess is provided in the first cap plate, the first region and the second region are provided in the second recess, the second cap plate is at least partially accommodated in the second recess, and at least the first region and the welding of the current collecting member are sealed.

12. A battery pack comprising the secondary battery according to any one of claims 1 to 11.

13. An electrical device comprising the battery pack of claim 12.