CN220553513U - Secondary battery, battery pack and electronic equipment - Google Patents

Abstract

The utility model provides a secondary battery, a battery pack and electronic equipment, and particularly relates to the field of batteries. The housing includes an opening; the electrode assembly is accommodated in the shell and is provided with a first tab facing the opening; the cover plate assembly comprises a cover plate main body, a pole and an insulating piece; the pole comprises an end plate and a connecting column, and grooves are formed in the circumference of the connecting column; the insulating piece includes first insulating piece, second insulating piece and connecting piece, first insulating piece separates to keep off the apron main part with between the end plate, the second insulating piece is located the apron main part is close to one side of electrode assembly, the connecting piece nest in the recess, and connect first insulating piece with the second insulating piece, first insulating piece the second insulating piece with the connecting piece passes through nanometer integrated into one piece of moulding plastics. The cover plate assembly remarkably reduces the number of assembly parts, simplifies assembly procedures and remarkably reduces cost.

Description

Secondary battery, battery pack and electronic equipment

Technical Field

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

Background

In the field of automobiles, new energy electric automobiles become a great development trend. The core power source of the electric automobile is a power battery, so the performance of the power battery is particularly important. The power battery is morphologically mainly divided into a square battery, a soft pack battery and a cylindrical battery. At present, the cylindrical battery comprises a shell, an electrode assembly and a cover plate assembly, wherein an upper insulating part and a lower insulating part of the cover plate assembly of the traditional cylindrical battery are of split structures, a sealing ring structure is required to be assembled, the number of parts is large, the assembly is complex, and the cost is high.

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, which improve the problems of the large number of battery cover assembly components, the complicated assembly, and the high cost.

To achieve the above and other related objects, the present utility model provides a secondary battery including a case, a battery assembly, and a cap plate assembly; the housing includes an opening; the electrode assembly is accommodated in the shell and is provided with a first tab facing the opening; the cover plate assembly comprises a cover plate main body, a pole and an insulating piece; the electrode post comprises an end plate and a connecting post, the end plate is arranged on one side, deviating from the electrode assembly, of the cover plate main body, one end of the connecting post is connected with the end plate, the other end of the connecting post penetrates through the cover plate main body and is electrically connected with the first electrode lug, and a groove is formed in the circumference of the connecting post; the insulating piece includes first insulating piece, second insulating piece and connecting piece, first insulating piece separates to keep off the apron main part with between the end plate, the second insulating piece is located the apron main part is close to one side of electrode assembly, the connecting piece nest in the recess, and connect first insulating piece with the second insulating piece, first insulating piece the second insulating piece with the connecting piece passes through nanometer integrated into one piece of moulding plastics.

In an example of the present utility model, the second insulating member is provided with a plurality of first through holes, and the plurality of first through holes penetrate in a thickness direction of the second insulating member.

In one example of the present utility model, the end plate and the connecting post are of different metal materials.

In an example of the present utility model, the end plate includes a boss protruding toward the electrode assembly side, the boss is fixedly connected to the connection post toward one side of the electrode assembly, and the boss has a height of 0 to 3mm.

In an example of the present utility model, the groove is an annular groove, and the annular groove and the pole are coaxially disposed, and a surface of the groove includes non-uniform nano-micropores.

In an example of the present utility model, an explosion-proof valve is disposed on the cover main body, and a second through hole corresponding to the explosion-proof valve is disposed on the second insulating member.

In one example of the utility model, the first insulator includes a flange that surrounds the sidewall of the end plate.

In an example of the present utility model, the cover main body is provided with a positioning structure, and the positioning structure includes a protrusion disposed along an outer periphery of the cover main body, and the protrusion is in lap joint with a side wall end surface of the housing.

The utility model provides a battery pack comprising the secondary battery.

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

According to the secondary battery, the first insulating part for isolating the cover plate main body and the pole and the second insulating part for isolating the cover plate main body and the electrode assembly in the cover plate assembly are integrally formed through nano injection molding, so that the number of parts for assembling the battery can be remarkably reduced, the assembling process is simplified, and the cost is reduced; the connecting column circumference at utmost point post sets up the recess, and the connecting piece nestification of insulating part is in the recess of connecting column, can increase the area of contact of connecting piece and connecting column, strengthens the sealed effect of insulating part.

Drawings

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

Fig. 1 is a schematic view showing the overall structure of a secondary battery according to an embodiment of the present utility model;

fig. 2 is a top view of a secondary battery according to an embodiment of the present utility model;

fig. 3 is a schematic cross-sectional structure of the secondary battery of fig. 2 taken along the line A-A;

FIG. 4 is an enlarged view of a portion of FIG. 3 at area A;

fig. 5 is a schematic exploded view of a cap assembly of a secondary battery according to an embodiment of the present utility model;

fig. 6 is a schematic structural view of a post of the secondary battery according to an embodiment of the present utility model;

fig. 7 is a top view of a post of a secondary battery according to an embodiment of the present utility model;

FIG. 8 is a schematic cross-sectional view of the post of FIG. 7 taken along section line B-B;

FIG. 9 is a schematic diagram of a battery pack according to an embodiment of the utility model;

fig. 10 is a schematic diagram of an electronic device according to an embodiment of the utility model.

Description of element reference numerals

10. A secondary battery; 100. a housing; 110. an end wall; 120. a sidewall; 200. an electrode assembly; 210. a first tab; 300. a cover plate assembly; 310. a cover plate main body; 311. a convex portion; 312. an explosion-proof valve; 320. a pole; 321. an end plate; 3211. a boss; 322. a connecting column; 3221. a groove; 330. an insulating member; 331. a first insulating member; 3311. a flange; 332. a second insulating member; 3321. a first through hole; 3322. a second through hole; 333. a connecting piece; 400. a current collecting member; 20. a battery pack; 201. a case; 202. a cover plate; 30. an electronic device; 301. a working part.

Detailed Description

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

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 10, the present utility model provides a secondary battery 10, a battery pack 20, and an electronic device 30. In the secondary battery 10, the cover plate assembly 300 is in insulating and sealing connection with the cover plate main body 310 and the pole 320 through the nano injection molding process, the air tightness of the cover plate assembly 300 is enhanced, and the insulating piece 330 is integrally formed, so that a sealing ring structure is omitted, the number of assembly parts is obviously reduced, and the assembly procedure is simplified.

Referring to fig. 1 to 4, the secondary battery 10 includes a case 100, an electrode assembly 200, and a cap plate assembly 300.

The case 100 has a receiving cavity formed therein for receiving the electrode assembly 200, an electrolyte (not shown), and other components, and the receiving cavity may be open at one end or open at both ends. The housing 100 may be of various shapes, such as a cylinder, a rectangular parallelepiped, etc. The shape of the case 100 may be determined according to the specific shape of the electrode assembly 200. For example, if the electrode assembly 200 has a cylindrical structure, a cylindrical case may be used; if the electrode assembly 200 has a rectangular parallelepiped structure, a rectangular parallelepiped case may be selected. The material of the housing 100 may be various, such as copper, iron, aluminum, steel, aluminum alloy, etc., and in order to prevent the housing 100 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 100. In one embodiment, housing 100 includes an end wall 110 and a side wall 120 surrounding end wall 110, side wall 120 and end wall 110 together defining a cylinder closed at one end and open at the other.

The electrode assembly 200 is accommodated in the case 100, and the electrode assembly 200 is a component in which an electrochemical reaction occurs in the battery cell. One or more electrode assemblies 200 may be contained within the case 100. The electrode assembly 200 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is generally provided between the positive electrode sheet and the negative electrode sheet. The positive electrode plate comprises a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode current collector; the positive electrode current collector comprises a positive electrode coating area and a positive electrode lug connected to the positive electrode coating area, wherein the positive electrode coating area is coated with a positive electrode active material layer, and the positive electrode lug is not coated with the positive electrode active material layer. The negative electrode plate comprises a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode current collector; the negative electrode current collector comprises a negative electrode coating area and a negative electrode tab connected to the negative electrode coating area, wherein the negative electrode coating area is coated with a negative electrode active material layer, and the negative electrode tab is not coated with the negative electrode active material layer. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate or the like. The material of the anode current collector may be copper, the anode active material layer includes an anode active material, and the anode active material may be carbon or silicon, or the like. The separator may be made of PP (polypropylene) or PE (polyethylene). In order to protect and insulate the battery cell, the battery cell can be coated with an insulating film, and the insulating film can be synthesized by PP, PE, PET, PVC or other high polymer materials. In an embodiment, the two ends of the electrode assembly 200 in the length direction are respectively provided with a first tab 210 and a second tab, and the polarities of the first tab 210 and the second tab are opposite, wherein the first tab 210 faces the opening of the housing 100, and the first tab 210 may be a negative tab or a positive tab.

Referring to fig. 3 and 4, the cover assembly 300 covers the opening of the housing 100 and forms a sealing connection. The cap plate assembly 300 includes a cap plate body 310, a post 320, and an insulator 330. The cap body 310 is welded or integrally connected with the case 100. In one embodiment, the cover body 310 and the case 100 are coupled by welding. In order to facilitate welding, the outer edge of the cover body 310 is provided with a positioning structure to prevent the cover body 310 from being dislocated from the housing 100 during welding. Specifically, the positioning structure includes a protrusion 311 provided along the outer circumference of the cap body 310, and the protrusion 311 extends in the radial direction of the cap body 310. The convex part 311 is in overlap joint with the end surface of the side wall 120, the end surface of the convex part 311 is abutted with the end surface of the side wall 120, so that the axial positioning of the cover plate main body 310 on the shell 100 is realized, the circumferential side wall of the convex part 311 is matched with the inner surface of the shell 100, and the radial positioning of the cover plate main body 310 on the shell 100 is realized. After welding, the tab 311 and the sidewall 120 are at least partially melted and connected together.

The cap body 310 and the case 100 have the same polarity. Illustratively, the end wall 110 of the housing 100 is electrically connected to the second tab, the housing 100 is positively charged when the second tab is a positive tab, the cap body 310 welded to the housing 100 is positively charged, and the housing 100 is negatively charged when the second tab is a negative tab, the cap body 310 welded to the housing 100 is negatively charged. The case 100 and the cover body 310 may be made of the same material or different materials as long as they can be connected by welding.

Referring to fig. 4 to 8, in an embodiment, a post hole penetrating in a thickness direction is formed in a cover body 310, a post 320 includes an end plate 321 and a connecting post 322, the end plate 321 is disposed on a side of the cover body 310 facing away from the electrode assembly 200, one end of the connecting post 322 penetrates the post hole and is connected with the post hole in an insulating manner, and the other end of the connecting post 322 is fixedly connected with the end plate 321 and is located on a side of the cover body 310 facing away from the electrode assembly 200. The insulating connection between the connection post 322 and the post hole may be accomplished in various ways. Insulation may be achieved, for example, by an insulating washer interposed between the connection post 322 and the post hole. Alternatively, insulation may be achieved by forming an insulation coating layer on a portion of the connection post 322. Along the height direction of the secondary battery 10, the front projection of the end plate 321 on the cover main body 310 covers the post hole, the connection post 322 penetrates through the cover main body 310 and is electrically connected with the first tab 210, the connection post 322 may be directly electrically connected with the first tab 210, for example, the connection post 322 is welded to the first tab 210, or the connection post 322 and the first tab 210 may be electrically connected through other conductive structures. The grooves 3221 are formed in the connecting columns 322 in the circumferential direction, the insulators 330 are nested in the grooves 3221, the contact area between the insulators 330 and the connecting columns 322 is increased, and the air tightness of the cover plate assembly 300 is enhanced. The end plate 321 and the connecting post 322 are made of different metal materials, for example, the end plate 321 is made of aluminum material, the connecting post 322 is made of copper material, and the end plate 321 is made of aluminum material so as to be convenient to weld with the external bus because the external bus is made of aluminum-containing material; the connection column 322 is made of copper, and when the first tab 210 is a negative tab, the connection column 322 is in a low-potential state, so that the connection column 322 can be prevented from being corroded by electrolyte. The end plate 321 is fixedly connected with the connecting post 322, and the connection mode of the end plate 321 and the connecting post 322 is not limited herein, and different combination modes or forming processes can be selected according to different use occasions, for example, hot rolling forming or welding forming are adopted.

Preferably, the end plate 321 includes a boss 3211, the boss 3211 protrudes toward the electrode assembly 200, the boss 3211 is fixedly connected to the connection post 322 on the side facing the electrode assembly 200, and a copper-aluminum composite interface is formed at the connection between the end plate 321 and the connection post 322. The end plate 321 and the connecting post 322 are generally connected by friction welding, and in order to ensure the welding effect, the connecting surface of the end plate 321 and the connecting post 322 is milled before the friction welding of the end plate 321 and the connecting post 322, so that the connecting surface of the end plate 321 and the connecting post 322 is smooth. The boss 3211 is arranged on the end plate 321, and when the end plate 321 is milled, only the surface of the boss 3211 is required to be milled, and the whole end surface of the end plate 321 facing the electrode assembly 200 is not required to be milled, so that the material waste is reduced. The height of the boss 3211 is 0 to 3mm, and for example, the height of the boss 3211 may be any value in the range of 0 to 3mm such as 1mm, 2mm, or 3mm.

Referring to fig. 3 to 5, in an embodiment, the insulating member 330 includes a first insulating member 331, a second insulating member 332, and a connecting member 333, wherein the first insulating member 331 is blocked between the cap body 310 and the end plate 321 to isolate the end plate 321 from the cap body 310, and the second insulating member 332 is located at a side of the cap body 310 close to the electrode assembly 200. The connecting member 333 is nested in the groove 3221 and connects the first insulating member 331 and the second insulating member 332, and the first insulating member 331, the second insulating member 332, and the connecting member 333 are integrally formed by nano injection molding. Preferably, the first insulating member 331 further includes a flange 3311, and the flange 3311 is wrapped around the sidewall of the end plate 321. The provision of the flange 3311 can increase the contact area of the first insulator 331 with the end plate 321 for better sealability while reducing the creepage effect of the cap body 310 with the pole 320. The second insulating member 332 is provided with a plurality of first through holes 3321, and the plurality of first through holes 3321 are penetrated along the thickness direction of the second insulating member 332, so that the first through holes 3321 can be filled with electrolyte, and the electrolyte is ensured to fully infiltrate the electrode assembly 200. The first through holes 3321 may be uniformly distributed on the second insulating member 332, or may be distributed in a certain arrangement order according to actual circumstances. In other embodiments, a plurality of grooves may be disposed on the second insulating member 332, where the number and depth of the grooves are not limited, so long as the electrolyte fully infiltrates the electrode assembly 200.

When the cover plate assembly 300 is assembled, the cover plate main body 310 and the pole 320 are assembled and placed in a mold, and then injection molding is injected into the mold, so that the insulating sealing member 330 is tightly combined with the cover plate main body 310 and the pole 320 through a nano injection molding process, and the insulating and sealing functions are achieved. The groove 3221 on the connecting post 322 is an annular groove, and the annular groove is coaxially arranged with the pole 320. Before the cover plate assembly 300 is assembled, the connecting column 322 is subjected to nano-scale microporation treatment, uneven nano micropores are formed on the surface of the groove 3221, so that the connecting column 322 is better combined with injection molding glue, and the connection strength of the connecting column 322 and the connecting piece 333 is improved. Compared with the traditional cover plate assembly, the cover plate assembly has the advantages that the sealing ring is omitted, in addition, the manufacturing process is greatly simplified, the riveting and welding processes are omitted, and therefore the manufacturing process of the cover plate assembly 300 is more controllable and the performance is more reliable. The material of the injection molding material is selected from one or more of PP, PPs (Polyphenylene Sulfide ), PBT (Polybutylene Terephthalate, polybutylene terephthalate) or PA (Polyamide), and in order to prevent the expansion and contraction speed of the insulating member 330 from being higher than those of the cover main body 310 and the pole 320, some fiber (glass fiber or carbon fiber) is added to make the expansion and contraction of the insulating member 330 similar to those of the cover main body 310 and the pole 320.

Referring to fig. 2 to 4, a pressure relief mechanism is provided on the cap body 310, and is configured to be actuated to relieve the internal pressure when the internal pressure of the secondary battery 10 reaches a threshold value. The threshold design varies according to design requirements. The threshold value may depend on the material of one or more of the positive electrode tab, the negative electrode tab, the electrolyte, and the separator in the secondary battery 10. The pressure release mechanism may take the form of, for example, an explosion-proof valve, a gas valve, a pressure release valve, or a safety valve, and may specifically take the form of a pressure sensitive element or a construction, i.e., when the internal pressure of the housing 100 reaches a predetermined threshold, the pressure release mechanism performs an action or a weak structure provided in the pressure release mechanism breaks, thereby forming an opening or a channel through which the internal pressure or temperature can be released. By "actuated" as referred to herein is meant that the pressure relief mechanism is actuated or activated to a state such that the internal pressure of the housing 100 is relieved. The actions generated by the pressure relief mechanism may include, but are not limited to: at least a portion of the pressure relief mechanism breaks, tears or opens, etc. Upon actuation of the pressure relief mechanism, the high temperature, high pressure material within the housing 100 may be expelled as a discharge outwardly from the location of actuation. In this way, the housing 100 can be depressurized under controlled pressure, thereby avoiding potentially more serious accidents. Emissions from the housing 100 include, but are not limited to: electrolyte, dissolved or split positive and negative electrode sheets, fragments of separators, high temperature and high pressure gases generated by the reaction, flame, and the like. In an embodiment, the cover body 310 is provided with an explosion-proof valve 312, and the explosion-proof valve 312 may be integrally formed with the cover body 310, and may be two separately provided members, which are welded, riveted, adhered or otherwise connected. The second insulating member 332 is provided with a second through hole 3322 corresponding to the explosion-proof valve 312, and when the secondary battery 10 is thermally out of control, the discharge generated from the electrode assembly 200 is discharged through the explosion-proof valve 312 to achieve axial directional explosion, reduce the accumulation of high-temperature gas inside the case 100, and prevent the case 100 from explosion in the lateral direction. The cross-sectional shape of the second through hole 3322 may be circular, or may be other shapes, such as rectangle, square, etc., where the cross-sectional shape of the second through hole 3322 is not limited, and the requirement of discharging the effluent during use may be satisfied.

Referring to fig. 3 and 4, in one embodiment, the secondary battery 10 further includes a current collecting member 400, and the current collecting member 400 is used to connect the first tab 210 and the connection post 322. The current collecting member 400 conducts the first tab 210 and the connection post 322, and thus makes the polarity of the post 320 the same as that of the first tab 210. The current collecting member 400 may be connected to the first tab 210 by welding, bonding, or other means to achieve electrical connection with the first tab 210. By providing the current collecting member 400 to connect the first tab 210 and the post 320, the current collecting member 400 can reduce the difference in conductive paths between different regions of the first tab 210 and the post 320, improve the uniformity of the current density of the first electrode sheet, reduce the internal resistance, and improve the overcurrent capacity and the charging efficiency of the secondary battery 10.

Referring to fig. 9, the present utility model also provides a battery pack 20, the battery pack 20 including the secondary battery 10 of any one of the above. In one embodiment, the battery pack 20 includes a case 201, a case cover 202, and a plurality of secondary batteries 10, the plurality of secondary batteries 10 being placed in the case 201 in series or parallel with each other, or a mixture of series and parallel, the case cover 202 being covered on the case 201 to protect the plurality of secondary batteries 10. The battery pack 20 may include a battery pack thermal management system, a circuit board, and the like in addition to the secondary battery 10 of the present utility model, and will not be described in detail herein.

The present utility model further provides an electronic device 30, where the electronic device 30 includes a working portion 301 and the battery pack 20, and the working portion 301 is electrically connected to the battery pack 20 to obtain power support. Referring to fig. 10, in an embodiment, the electronic device 30 is a vehicle, which 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 portion 301 is a vehicle body, and the battery pack 20 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. In other embodiments, the electronic device 30 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 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.

According to the secondary battery, the first insulating part for isolating the cover plate main body and the pole and the second insulating part for isolating the cover plate main body and the electrode assembly in the cover plate assembly are integrally formed through nano injection molding, so that the number of parts for assembling the battery can be remarkably reduced, the assembling process is simplified, and the cost is reduced; the connecting column circumference at utmost point post sets up the recess, and the connecting piece nestification of insulating part is in the recess of connecting column, can increase the area of contact of connecting piece and connecting column, strengthens the sealed effect of insulating part. Therefore, the utility model effectively overcomes some practical problems in the prior art, thereby having high utilization value and use significance.

The above embodiments are merely illustrative of the principles of the present utility model and its effectiveness, and are not intended to limit the utility model. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the utility model. Accordingly, it is intended that all equivalent modifications and variations of the utility model be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims (10)

1. A secondary battery, characterized by comprising:

a housing including an opening;

an electrode assembly accommodated in the case and having a first tab facing the opening;

a cover plate assembly comprising: the device comprises a cover plate main body, a pole and an insulating piece;

the electrode post comprises an end plate and a connecting post, the end plate is arranged on one side, deviating from the electrode assembly, of the cover plate main body, one end of the connecting post is connected with the end plate, the other end of the connecting post penetrates through the cover plate main body and is electrically connected with the first electrode lug, and a groove is formed in the circumference of the connecting post;

the insulating piece includes first insulating piece, second insulating piece and connecting piece, first insulating piece separates to keep off the apron main part with between the end plate, the second insulating piece is located the apron main part is close to one side of electrode assembly, the connecting piece nest in the recess, and connect first insulating piece with the second insulating piece, first insulating piece the second insulating piece with the connecting piece passes through nanometer integrated into one piece of moulding plastics.

2. The secondary battery according to claim 1, wherein the second insulating member is provided with a plurality of first through holes penetrating in a thickness direction of the second insulating member.

3. The secondary battery according to claim 1, wherein the end plate and the connecting post are of different metal materials.

4. The secondary battery according to claim 1, wherein the end plate includes a boss protruding toward the electrode assembly side, the boss being fixedly connected to the connection post toward the electrode assembly side, and the boss having a height of 0 to 3mm.

5. The secondary battery according to claim 1, wherein the groove is an annular groove, and the annular groove is disposed coaxially with the post, and a surface of the groove includes non-uniform nano-micropores.

6. The secondary battery according to claim 1, wherein an explosion-proof valve is provided on the cap body, and a second through hole corresponding to the explosion-proof valve is provided on the second insulating member.

7. The secondary battery according to claim 1, wherein the first insulating member includes a flange surrounding a sidewall of the end plate.

8. The secondary battery according to claim 1, wherein a positioning structure is provided on the cap body, the positioning structure including a protrusion provided along an outer periphery of the cap body, the protrusion being in lap-fit with a side wall end face of the case.

9. A battery pack, characterized in that the battery pack comprises the secondary battery according to any one of claims 1 to 8.

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