CN117832580A - Battery and method for assembling battery - Google Patents

Abstract

The invention discloses a battery and an assembling method of the battery, the battery comprises a shell and a negative electrode connecting piece, the shell is provided with an inner cavity with one end open, the negative electrode connecting piece is positioned in the inner cavity, one surface of the negative electrode connecting piece is provided with a tab connecting area and a shell connecting area which is annularly arranged in the tab connecting area, and the lower surface of the shell connecting area is attached to and welded on the upper surface of a bottom plate of the shell, or the shell and the negative electrode connecting piece are integrally formed. The battery includes casing and negative pole connection piece, and the lower surface of the casing connecting region of negative pole connection piece is laminated with the upper surface of the bottom plate of casing, simultaneously with casing connecting region and bottom plate welding, realized that the face of negative pole connection piece and casing is connected and welded, compared with prior art, increased the overlap area by the welded part, increased the welding area correspondingly, reduced the welding degree of difficulty, improved welding quality, solved the rosin joint and welded problem of wearing the casing. The negative electrode connecting sheet and the shell are integrally formed, so that welding positions are reduced, assembly efficiency is improved, and connection quality is improved.

Description

Battery and method for assembling battery

Technical Field

The invention relates to the technical field of batteries, in particular to a battery and an assembling method of the battery.

Background

The lithium battery has the advantages of standardization, consistency, safety and the like, is widely applied to automobiles, is used as a power battery, and simultaneously has higher requirements. For example, lithium batteries are required to achieve higher mass energy density, higher production efficiency, lower production cost, higher safety, and the like. At present, a thin-wall steel shell is generally adopted as a shell of a large-cylinder lithium battery, and due to the limitation of thickness and size of the thin-wall steel shell, when the negative electrode connecting sheet is welded and electrically connected with the shell, the peripheral edge of the negative electrode connecting sheet is welded with the side wall of the shell, so that the overlapping area of welding lap joint of a welding part is small, the welding difficulty is high, the problem that the virtual welding or the shell is welded through exists, the product qualification rate is low, the product delivery is affected, and meanwhile, the production cost is high.

Disclosure of Invention

The invention aims to overcome the defect of poor connection effect of a shell and a negative electrode connecting sheet of a battery in the prior art, and provides the battery and an assembly method of the battery.

The invention solves the technical problems by the following technical scheme:

the battery comprises a shell and a negative electrode connecting piece, wherein the shell is provided with an inner cavity with one end being open, the negative electrode connecting piece is positioned in the inner cavity, one surface of the negative electrode connecting piece is provided with a lug connecting area and a shell connecting area which is annularly arranged in the lug connecting area, and the lower surface of the shell connecting area is attached to and welded on the upper surface of a bottom plate of the shell, or the shell and the negative electrode connecting piece are integrally formed.

In this scheme, this battery includes casing and negative pole connection piece, and the lower surface of the casing connecting region of negative pole connection piece is laminated with the upper surface of the bottom plate of casing, simultaneously with casing connecting region and bottom plate welding, realized the face connection of negative pole connection piece and casing and welded, compare the side and the casing welding of negative pole connection piece with prior art, increased the overlap area by the welding position, increased the welding area correspondingly, reduced the welding degree of difficulty, improved welding quality, solved the rosin joint and welded problem of wearing the casing. The negative electrode connecting sheet and the shell are integrally formed, so that the welding step of the negative electrode connecting sheet and the shell is omitted, correspondingly, the welding part is reduced, the manufacturing process is simplified, the assembly efficiency is improved, and the connection quality of the negative electrode connecting sheet and the shell is improved. The tab connection area is used for connecting the tab of the core pack. The opening in the upper end of the housing is used to package the core into the interior cavity of the housing.

Preferably, the tab connection region is a boss protruding toward the tab direction of the core pack.

In this scheme, set up the utmost point ear connecting region into bellied boss, be convenient for with the utmost point ear welding of core package, make utmost point ear and negative pole connection piece electricity be connected reliable and stable.

Preferably, the lower surface of the negative electrode connecting sheet is recessed towards the lug direction of the core pack to form a groove, the upper surface of the bottom plate is provided with a protruding part matched with the groove, and the protruding part is embedded in the groove.

In this scheme, the bellying inlays and locates the recess for the installation location of negative pole connection piece and bottom plate improves the installation accuracy, also can improve the fixed effect of being connected of negative pole connection piece and bottom plate simultaneously.

Preferably, the bottom plate is provided with mounting holes, and the mounting holes are correspondingly arranged with the lug connection areas.

In this scheme, owing to the mounting hole corresponds the setting with the utmost point ear connecting region, the utmost point ear that is convenient for utilize laser to pass through the mounting hole and see through the negative pole connection piece, welds the utmost point ear of core package to the utmost point ear connecting region, has reduced the welding degree of difficulty, has improved welding quality.

Preferably, the battery further comprises an explosion-proof piece, wherein the explosion-proof piece is embedded in the mounting hole, and the peripheral edge of the explosion-proof piece is in sealing connection with the bottom plate.

In this scheme, when the pressure in the casing exceeds the pressure of predetermineeing, the explosion-proof piece is destroyed, reaches the purpose of quick pressure release, prevents the battery explosion, improves the security.

Preferably, the lower surface of the rupture disc is not lower than the lower surface of the base plate.

In this scheme, adopt above-mentioned structure setting, the lower surface of explosion-proof piece is not less than the lower surface of bottom plate, ensures that the explosion-proof piece can accurately open the valve. If the explosion-proof sheet is arranged above the supporting surface of the bottom plate, the explosion-proof sheet does not participate in the supporting of the battery, so that a cavity is formed between the explosion-proof sheet and the supporting surface on the bottom plate, and the explosion-proof sheet is not easy to damage by touching, so that the accurate valve opening of the explosion-proof sheet is ensured. In other embodiments, the lower surface of the rupture disk and the lower surface of the bottom plate may be disposed at the same height.

Preferably, a first through hole is formed in the middle of the tab connection region, and the first through hole is located in a projection region of the mounting hole in the vertical direction;

and/or the lug connection area is provided with a plurality of second through holes, the plurality of second through holes are uniformly distributed in the lug connection area, and the second through holes are positioned in the projection area of the mounting holes in the vertical direction.

In this scheme, first through-hole and second through-hole all can be used for filling electrolyte to core package inside, perhaps, when the pressure of inner chamber exceeds the pressure of predetermineeing, first through-hole and second through-hole also can be used for the exhaust. The second through holes can realize rapid exhaust of the battery, prevent explosion of the battery and improve safety. Meanwhile, when the battery is assembled, the first through hole and the second through hole can be used for positioning and limiting.

A method of assembling a battery, which is applied to assembling the battery as above, the method of assembling comprising the steps of:

s1, welding a negative electrode connecting sheet at the bottom of an inner cavity of a shell;

s2, packaging the core into an inner cavity of the shell, and welding the lower end tab of the core package to the negative electrode connecting sheet.

In the scheme, the assembly method comprises the steps of firstly welding the negative electrode connecting sheet at the bottom of the inner cavity of the shell, then packaging the core package into the shell, welding the lower end lug of the core package to the negative electrode connecting sheet, and when the welding of the negative electrode connecting sheet and the shell is carried out, the welding is convenient due to the fact that the core package is not interfered, the welding quality is high, the welding position can be conveniently detected and cleaned after the welding is finished, and the yield of products is high.

Preferably, in step S1, the lower surface of the negative electrode connecting sheet is bonded and welded to the upper surface of the bottom plate of the case.

In this scheme, realized that the face of negative pole connection piece and casing is connected and welded, compare the side with the casing welding of negative pole connection piece with prior art, increased the area of overlap of being welded the position, increased the welding area correspondingly, reduced the welding degree of difficulty, improved welding quality, solved the rosin joint and welded the problem of wearing the casing.

Preferably, the bottom plate is provided with a mounting hole, and in step S2, laser is used to pass through the mounting hole and penetrate through the negative electrode connecting sheet so as to weld the lower end tab of the core package to the negative electrode connecting sheet.

In this scheme, follow the mounting hole on the bottom plate and utilize laser to weld the lower extreme utmost point ear of core package, compare from the top of core package to weld, the distance is nearer, and the operation is also simpler, has improved welding quality. Of course, the welding can be performed on the lower-end lugs from the two ends of the core pack at the same time, so that the welding speed is increased, and the welding quality is improved.

Preferably, the assembling method further comprises the steps of:

the positive electrode connecting sheet is arranged at the top of the inner cavity of the shell and welded with the upper end tab of the core pack;

assembling the positive electrode cover plate above the positive electrode connecting sheet and welding the positive electrode cover plate and the positive electrode connecting sheet;

and welding the positive electrode connecting sheet with the shell.

In the scheme, the steps are adopted to complete the assembly and connection of the positive electrode connecting sheet and the positive electrode cover plate.

Preferably, the assembling method further comprises the steps of:

filling liquid into the core bag through a first through hole on the negative electrode connecting sheet;

and installing the explosion-proof sheet in the installation hole of the bottom plate, and enabling the lower surface of the explosion-proof sheet not to be lower than the lower surface of the bottom plate.

In this scheme, because negative pole connection piece sets up the negative pole end at the battery, after accomplishing annotating the liquid operation, can seal first through-hole, then install the explosion-proof piece in the outside of first through-hole, further improve the sealed effect of battery. If the lower surface of the explosion-proof piece is higher than the lower surface of the bottom plate, the explosion-proof piece is positioned above the supporting surface of the bottom plate, and the explosion-proof piece does not participate in the support of the battery, so that a cavity is formed between the explosion-proof piece and the supporting surface on the bottom plate, and the explosion-proof piece is not easy to be damaged by touching, so that the accurate valve opening of the explosion-proof piece is ensured. In other embodiments, the lower surface of the rupture disk and the lower surface of the bottom plate may be disposed at the same height.

On the basis of conforming to the common knowledge in the field, the above preferred conditions can be arbitrarily combined to obtain the preferred examples of the invention.

The invention has the positive progress effects that: the battery comprises a shell and a negative electrode connecting piece, wherein the lower surface of a shell connecting area of the negative electrode connecting piece is attached to the upper surface of a bottom plate of the shell, meanwhile, the shell connecting area is welded with the bottom plate, the surface connection and welding of the negative electrode connecting piece and the shell are realized, the overlapping area of a welded part is increased compared with the welding of the side edge of the negative electrode connecting piece and the shell in the prior art, the welding area is correspondingly increased, the welding difficulty is reduced, the welding quality is improved, and the problems of cold welding and welding through the shell are solved. The negative electrode connecting sheet and the shell are integrally formed, so that the welding step of the negative electrode connecting sheet and the shell is omitted, correspondingly, the welding part is reduced, the manufacturing process is simplified, the assembly efficiency is improved, and the connection quality of the negative electrode connecting sheet and the shell is improved. The tab connection area is used for connecting the tab of the core pack. The opening in the upper end of the housing is used to package the core into the interior cavity of the housing.

Drawings

Fig. 1 is a schematic structural view of a case and a negative electrode electric connection sheet of a battery according to a preferred embodiment of the present invention.

Fig. 2 is a schematic structural view (a) of a negative electrode electric connection sheet of a battery according to a preferred embodiment of the present invention.

Fig. 3 is a schematic structural view of a negative electrode electric connection sheet of a battery according to a preferred embodiment of the invention (ii).

Fig. 4 is a schematic structural view of a battery case according to a preferred embodiment of the present invention.

Fig. 5 is a schematic view illustrating a structure of a battery according to a preferred embodiment of the present invention.

Fig. 6 is a cross-sectional view taken along line A-A in fig. 5.

Fig. 7 is an enlarged view of a portion B in fig. 6.

Fig. 8 is an enlarged view of a portion C in fig. 7.

Fig. 9 is an exploded view of a battery according to a preferred embodiment of the present invention.

Fig. 10 is a flowchart of an assembling method of a battery according to a preferred embodiment of the present invention.

Reference numerals illustrate:

shell 1

Bottom plate 11

The upper surface 11a of the base plate

Lower surface 11b of the base plate

Mounting hole 111

Boss 112

Negative electrode connecting piece 2

Tab connection region 21

Housing attachment area 22

Lower surface 22a of the housing attachment area

Groove 23

First through hole 24

Second through hole 25

Explosion-proof sheet 3

Lower surface 3a of the rupture disc

Core pack 4

Tab 41

Positive electrode connecting piece 5

Positive electrode cover plate 6

Battery 100

Detailed Description

The invention will now be more fully described by way of example only and with reference to the accompanying drawings, but the invention is not thereby limited to the scope of the examples described.

As shown in fig. 1-9, the present embodiment discloses a battery 100, which includes a case 1 and a negative electrode connection piece 2, wherein the case 1 has an inner cavity with one end open, the negative electrode connection piece 2 is located in the inner cavity, one surface of the negative electrode connection piece 2 has a tab connection area 21 and a case connection area 22 surrounding the tab connection area 21, and a lower surface 22a of the case connection area is attached to and welded to an upper surface 11a of a bottom plate of the case 1. In this embodiment, the battery 100 includes the case 1 and the negative electrode connection piece 2, the lower surface 22a of the case connection area of the negative electrode connection piece 2 is attached to the upper surface 11a of the bottom plate of the case 1, and meanwhile, the case connection area 22 is welded with the bottom plate 11, so that the connection and welding of the negative electrode connection piece 2 and the case 1 are realized, and compared with the welding of the side edge of the negative electrode connection piece 2 and the case 1 in the prior art, the overlapping area of the welded part is increased, the welding area is correspondingly increased, the welding difficulty is reduced, the welding quality is improved, and the problems of cold welding and welding through the case 1 are solved. The tab connection region 21 is used to connect the tab 41 of the core pack 4. The opening at the upper end of the housing 1 is used to house the core pack 4 in the interior cavity of the housing 1. The bottom plate 11 of the housing 1 is used to support the battery.

In another embodiment, the housing 1 is integrally formed with the negative electrode tab 2. The negative electrode connecting sheet 2 and the shell 1 are integrally formed, so that the welding step of the negative electrode connecting sheet 2 and the shell 1 is omitted, correspondingly, the welding part is reduced, the manufacturing process is simplified, the assembly efficiency is improved, and the connection quality of the negative electrode connecting sheet 2 and the shell 1 is improved.

As shown in fig. 2 and fig. 6-9, in this embodiment, the tab connection region 21 is a boss protruding toward the tab 41 of the core pack 4, so as to facilitate welding with the tab 41 of the core pack 4, and make the electrical connection between the tab 41 and the negative electrode connection piece 2 stable and reliable. In order to facilitate arrangement of the lugs on the core package, the bosses are circular bosses so as to arrange more lugs in a smaller space.

As shown in fig. 1, 4, 7 and 8, the mounting holes 111 are formed in the bottom plate 11, and the mounting holes 111 are arranged corresponding to the tab connection areas 21, so that the tabs 41 of the core pack 4 can be welded to the tab connection areas 21 by laser through the mounting holes 111 and through the negative electrode connection pieces 2, welding difficulty is reduced, and welding quality is improved.

In the present embodiment, in order not to affect the strength of the base plate 11, the mounting hole 111 is provided in the boss 112, and the mounting hole 111 penetrates the boss 112. Of course, in other embodiments, the mounting holes may be offset from a portion of the boss.

As shown in fig. 8 and 9, the battery 100 further includes a rupture disc 3, the rupture disc 3 is embedded in the mounting hole 111, and the peripheral edge of the rupture disc 3 is connected with the bottom plate 11 in a sealing manner. When the pressure in the casing 1 exceeds the preset pressure, the explosion-proof sheet 3 is destroyed, the purpose of rapid pressure relief is achieved, the explosion of the battery 100 is prevented, and the safety is improved.

In this embodiment, as shown in fig. 6-8, the lower surface 3a of the explosion-proof sheet is higher than the lower surface 11b of the bottom plate, so that the explosion-proof sheet 3 is located above the supporting surface of the bottom plate 11, the explosion-proof sheet 3 does not participate in the supporting of the battery 100, a cavity is formed between the explosion-proof sheet 3 and the supporting surface on the bottom plate 11, and the explosion-proof sheet 3 is not easily damaged by touching, so as to ensure the accurate valve opening of the explosion-proof sheet 3. In this embodiment, the explosion-proof sheet 3 is circular, so that the explosion-proof sheet 3 is uniformly stressed and can be accurately opened while being convenient to install. Of course, in other embodiments, the lower surface 3a of the rupture disc and the lower surface 11b of the bottom plate may be disposed at the same height.

As shown in fig. 8, two annular steps are provided on the inner wall surface of the mounting hole 111 from top to bottom, and the rupture disc 3 is mounted on the annular step above, so that the rupture disc 3 is in a suspended state without receiving external force after being mounted.

As shown in fig. 8, a gap is further provided between the explosion-proof sheet 3 and the negative electrode connecting sheet 2, and the gap is used for preventing the explosion-proof sheet 3 from being opened by mistake. If there is no gap between the explosion-proof sheet 3 and the negative electrode connecting sheet 2, the core pack may have a tiny movement under the condition of temperature change or vibration, which may cause the negative electrode connecting sheet 2 to deform, thereby triggering the explosion-proof sheet 3 to open by mistake.

As shown in fig. 1 and 2, the middle of the tab connection region 21 is provided with a first through hole 24, and the first through hole 24 is located in a projection region of the mounting hole 111 in the vertical direction. The first through hole 24 is used for injecting electrolyte into the core pack 4, or the first through hole 24 can be used for exhausting when the pressure of the inner cavity exceeds a preset pressure. In this embodiment, the tab connection region 21 is further provided with a plurality of second through holes 25, the plurality of second through holes 25 are uniformly arranged in the tab connection region 21, and the second through holes 25 are located in the projection region of the mounting hole 111 in the vertical direction. The second through hole 25 is used for injecting electrolyte into the core pack 4, or the second through hole 25 can be used for exhausting when the pressure of the inner cavity exceeds the preset pressure. The plurality of second through holes 25 can realize rapid exhaustion of the battery 100, prevent explosion of the battery 100, and improve safety. Meanwhile, the first through-hole 24 and the second through-hole 25 can also be used for positioning and limiting use when the battery 100 is assembled.

The first through hole 24 and the second through hole 25 are both located in the projection area of the mounting hole 111 in the vertical direction, so that high-pressure gas can be ensured to act on the explosion-proof sheet 3 through the first through hole 24 and the second through hole 25, and accurate valve opening of the explosion-proof sheet 3 is ensured.

Of course, in other alternative embodiments, the first through hole 24 and the second through hole 25 may alternatively be provided. The number of second through holes 25 also requires a space for welding the tab 41 on the negative electrode tab.

As shown in fig. 6 to 8, the lower surface of the negative electrode connecting piece 2 is recessed toward the tab 41 of the core pack 4 to form a groove 23, the upper surface 11a of the bottom plate is provided with a protruding portion 112 adapted to the groove 23, and the protruding portion 112 is embedded in the groove 23 for mounting and positioning the negative electrode connecting piece 2 and the bottom plate 11, so that the mounting accuracy is improved, and meanwhile, the connection and fixation effects of the negative electrode connecting piece 2 and the bottom plate 11 can also be improved.

In order to allow the negative electrode tab 2 to be quickly mounted on the base plate 11, the outer diameter of the boss 112 on the base plate 11 is typically slightly smaller than the inner diameter of the recess 23.

To increase the assembly speed, the groove 23 is a circular groove and the boss 112 is a circular boss that fits into the circular groove.

As shown in fig. 6 and 9, the battery further includes a positive electrode connecting piece 5 and a positive electrode cover plate 6, the positive electrode connecting piece 5 is located in the housing 1 and welded with the upper end tab of the core pack 4, the positive electrode cover plate 6 is located at the outer side of the positive electrode connecting piece 5, the positive electrode cover plate 6 is welded with the positive electrode connecting piece 5, and the edge of the positive electrode cover plate 6 is welded with the housing 1. The middle part of the positive cover plate 6 is provided with a positive pole post which is electrically connected with the positive connecting sheet 5.

As shown in fig. 1 to 10, the present embodiment also discloses a method for assembling a battery, which is applied to the assembly of the battery 100 described above, and includes the steps of:

s1, welding a negative electrode connecting sheet 2 at the bottom of an inner cavity of a shell 1;

s2, the core pack 4 is arranged in the inner cavity of the shell 1, and the lower end tab 41 of the core pack 4 is welded to the negative electrode connecting sheet 2;

s3, mounting the positive electrode connecting sheet 5 on the top of the inner cavity of the shell 1 and welding the positive electrode connecting sheet with the upper end tab of the core pack 4;

s4, assembling the positive electrode cover plate 6 above the positive electrode connecting sheet 5 and welding the positive electrode cover plate 6 and the positive electrode connecting sheet 5;

s5, welding the positive electrode connecting sheet 5 with the shell 1;

s6, injecting liquid into the core pack 4 through the first through hole 24 on the negative electrode connecting sheet 2;

s7, mounting the explosion-proof sheet 3 on the mounting hole 111 on the bottom plate 11, and making the lower surface 3a of the explosion-proof sheet not lower than the lower surface 11b of the bottom plate.

In this embodiment, in steps S1 and S2, the negative electrode connection sheet 2 is welded at the bottom of the inner cavity of the housing 1, then the refill pack 4 is inserted into the housing 1 and the lower end tab 41 of the refill pack 4 is welded to the negative electrode connection sheet 2, when the welding between the negative electrode connection sheet 2 and the housing 1 is performed, the welding is convenient due to no interference of the refill pack 4, the welding quality is high, after the welding is finished, the welding position is also convenient to detect and clean, and the product with poor welding quality can be directly repaired, so that the yield of the product is high.

In step S1, the lower surface of the negative electrode connecting piece 2 is attached to and welded with the upper surface 11a of the bottom plate of the housing 1, so that the surface connection and welding between the negative electrode connecting piece 2 and the housing 1 are realized, and compared with the welding between the side edge of the negative electrode connecting piece 2 and the housing 1 in the prior art, the overlapping area of the welded part is increased, the welding area is correspondingly increased, the welding difficulty is reduced, the welding quality is improved, and the problems of cold welding and welding through the housing 1 are solved.

In step S2, since the mounting hole 111 is provided in the bottom plate 11, the lower end tab 41 of the core pack 4 is welded to the negative electrode tab 2 by passing through the mounting hole 111 and penetrating the negative electrode tab 2 by laser light at the time of welding. Compared with the welding from the upper part of the core pack 4, the welding distance is shorter, the operation is simpler, and the welding quality is improved. Of course, the lower end tab 41 may be welded from both ends of the core pack 4 at the same time, so as to increase the welding speed and improve the welding quality.

And assembling and connecting the positive electrode connecting sheet 5 and the positive electrode cover plate 6 through the steps S3-S5. At this time, the assembly of the main components at the upper end of the battery 100 is completed, and then the operations of injecting the electrolyte into the core pack 4 and installing the explosion-proof sheet 3 are performed.

In this embodiment, since the negative electrode connection tab 2 is disposed at the negative electrode end of the battery 100, in steps S6 and S7, after the injection operation is completed, the first through hole 24 may be closed, and then the explosion-proof sheet 3 is mounted at the mounting hole 111 on the bottom plate 11 outside the first through hole 24, thereby further improving the sealing effect of the battery 100.

When the explosion-proof sheet 3 is installed, the lower surface 3a of the explosion-proof sheet is higher than the lower surface 11b of the bottom plate, the explosion-proof sheet 3 is located above the supporting surface of the bottom plate 11, a cavity is formed between the explosion-proof sheet 3 and the supporting surface on the bottom plate 11, the explosion-proof sheet 3 does not participate in the supporting of the battery 100, and the explosion-proof sheet 3 is not easily damaged by touch, so that the accurate valve opening of the explosion-proof sheet 3 is ensured. Of course, in other embodiments, the lower surface of the rupture disc and the lower surface of the bottom plate may be disposed at the same height.

While specific embodiments of the invention have been described above, it will be appreciated by those skilled in the art that this is by way of example only, and the scope of the invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the principles and spirit of the invention, but such changes and modifications fall within the scope of the invention.

Claims (12)

1. The battery is characterized by comprising a shell and a negative electrode connecting piece, wherein the shell is provided with an inner cavity with one end being open, the negative electrode connecting piece is positioned in the inner cavity, one surface of the negative electrode connecting piece is provided with a tab connecting area and a shell connecting area which is annularly arranged in the tab connecting area, and the lower surface of the shell connecting area is attached to and welded on the upper surface of a bottom plate of the shell, or the shell and the negative electrode connecting piece are integrally formed.

2. The battery of claim 1, wherein the tab connection region is a boss protruding toward the tab direction of the core pack.

3. The battery of claim 2, wherein the lower surface of the negative electrode connecting piece is recessed toward the tab of the core pack to form a groove, and the upper surface of the bottom plate is provided with a protrusion adapted to the groove, and the protrusion is embedded in the groove.

4. A battery according to any one of claims 1 to 3, wherein the base plate is provided with mounting holes, the mounting holes being provided in correspondence with the tab connection regions.

5. The battery of claim 4, further comprising a rupture disc embedded in the mounting hole, the peripheral edge of the rupture disc being sealingly connected to the base plate.

6. The battery of claim 5, wherein a lower surface of the rupture disc is not lower than a lower surface of the bottom plate.

7. The battery according to claim 4, wherein a first through hole is formed in the middle of the tab connection region, and the first through hole is located in a projection region of the mounting hole in the vertical direction;

and/or, the lug connection area is provided with a plurality of second through holes, the second through holes are uniformly distributed in the lug connection area, and the second through holes are positioned in the projection area of the mounting hole in the vertical direction.

8. A method of assembling a battery, characterized in that it is applied to assembling a battery as claimed in any one of claims 1 to 7, the method comprising the steps of:

s1, welding a negative electrode connecting sheet at the bottom of an inner cavity of a shell;

s2, packaging the core into an inner cavity of the shell, and welding the lower end tab of the core package to the negative electrode connecting sheet.

9. The method of assembling a battery according to claim 8, wherein in step S1, the lower surface of the negative electrode connecting sheet is bonded and welded to the upper surface of the bottom plate of the case.

10.The method of assembling a battery according to claim 9, wherein the base plate is provided withIn step S2, a laser is used to pass through the mounting hole and penetrate through the negative electrode connecting piece, so as to weld the lower end tab of the core pack to the negative electrode connecting piece.

11. The method of assembling a battery according to claim 10, wherein the method of assembling further comprises the steps of:

the positive electrode connecting sheet is arranged at the top of the inner cavity of the shell and welded with the upper end tab of the core pack;

assembling the positive electrode cover plate above the positive electrode connecting sheet and welding the positive electrode cover plate and the positive electrode connecting sheet;

and welding the positive electrode connecting sheet with the shell.

12. The method of assembling a battery according to claim 11, wherein the method of assembling further comprises the steps of:

filling liquid into the core bag through a first through hole on the negative electrode connecting sheet;

and installing the explosion-proof sheet in the installation hole of the bottom plate, and enabling the lower surface of the explosion-proof sheet not to be lower than the lower surface of the bottom plate.