CN113300055B

CN113300055B - Connecting assembly of battery cell, lithium battery and assembling method

Info

Publication number: CN113300055B
Application number: CN202110550686.1A
Authority: CN
Inventors: 高冲; 程辉; 吴德
Original assignee: Gotion High Tech Co Ltd
Current assignee: Gotion High Tech Co Ltd
Priority date: 2021-05-17
Filing date: 2021-05-17
Publication date: 2022-03-18
Anticipated expiration: 2041-05-17
Also published as: CN113300055A

Abstract

The invention provides a connection assembly of a battery cell, comprising an end cover that can be fastened to one end of at least one battery cell, the end of the battery cell covered by the end cover has a positive electrode ear and a negative electrode ear, and the outer side of the end cover is provided with a Two pole pieces, the pole pieces are connected with a bottom piece on the inner side of the end cover, and the bottom piece can be welded and fixed with the positive electrode lug or the negative electrode lug. The present invention also provides a lithium battery including the connection assembly and an assembling method. The advantages of the present invention lie in that the bottom plate and the pole piece are connected together, which is convenient for fixing with the tabs of the battery core, the pole piece and the bottom plate are directly fixed on the connecting assembly, and the entire connecting assembly can be directly operated during assembly, without frequent Absorb the pole pieces and connecting pieces that are set separately, reduce equipment downtime caused by multiple pieces and missing pieces, and improve the utilization rate. When the pole piece is turned over, the tabs have been fixed, and there will be no interpolation of the tabs.

Description

Connecting assembly of battery cell, lithium battery and assembling method

Technical Field

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

Background

The traditional method for assembling the battery core of the lithium battery at present comprises the following steps: firstly, connecting two single cores together by adopting a butterfly welding process, namely welding two lugs with the same polarity together by utilizing ultrasonic waves through a connecting sheet and a protective sheet; secondly, the connecting sheet is welded with the poles with the corresponding same polarity together through laser, and a stopping frame is generally buckled at a welding position to prevent looseness in order to protect the poles, for example, an assembling device and an assembling method suitable for assembling a square lithium battery pole group are disclosed in the patent application with the publication number of CN 105261798A; combining the two single cores and fixing the two single cores through binding tapes; and fourthly, filling the battery cell into the aluminum shell, and finishing sealing welding through laser.

The method mainly has the following defects:

1. the connecting sheet and the protection sheet are single sheets, and the phenomena of multiple sheets, sheet shortage and the like frequently occur in the feeding process, so that the manufacturing utilization rate is low.

2. Connecting sheet, screening glass are carrying out ultrasonic bonding in-process with utmost point ear, very easily appear rocking, are difficult to guarantee the positioning accuracy of both on utmost point ear, lead to ultrasonic bonding's quality relatively poor.

3. The manufacturing process of the buckling stopping frame is complex, the processes of caching, feeding, buckling height detection and the like of the buckling stopping frame are involved, and the buckling quality is difficult to effectively guarantee.

4. When the electric core is combined, the electric core body is inserted into the lug easily to cause battery short circuit, and the connecting sheet is easy to damage the lug of the electric core when being bent, so that the manufacturing qualified rate is reduced.

5. The method has a narrow application range and can only be used for assembling the lithium battery when the battery cell is an even number. And when the number of the battery cells is more than 4, the more serious the pole lug interpolation phenomenon of the method is, and the problem is difficult to effectively solve.

Disclosure of Invention

The invention aims to provide a connecting assembly of a battery core, a lithium battery and an assembling method thereof, so as to simplify the assembling process and improve the assembling quality.

The invention solves the technical problems through the following technical scheme: the utility model provides a coupling assembling of electricity core, is including the end cover that can the lock in at least one electricity core one end, the one end that electricity core was covered by the end cover has positive electrode tab and negative pole ear, the end cover outside is provided with two pole pieces, the pole piece is connected with the film that is in the end cover inboard, the film can with positive electrode tab or negative pole ear welded fastening.

The negative plate and the pole piece are connected together, so that the negative plate and the pole piece are conveniently fixed with a pole lug of a battery cell, the pole piece and the negative plate are directly fixed on the connecting assembly, the connecting assembly is directly operated integrally during assembly, the pole piece and the connecting plate which are separately arranged do not need to be frequently sucked, equipment halt caused by multiple pieces and lacking of pieces is reduced, and the utilization rate is improved.

Preferably, at least one side of the bottom plate is provided with a pressing plate capable of being turned over on the bottom plate, and the positive electrode lug or the negative electrode lug is clamped between the pressing plate and the bottom plate and is welded and fixed.

Preferably, the end cover has a substantially same profile as the end face of at least one of the arranged battery cells, a baffle plate perpendicular to the end cover is further disposed on the periphery of the end cover, the end cover is matched with the end face of the arranged battery cells, the arranged battery cells are surrounded and wrapped by the baffle plate, and the end cover and the baffle plate are insulators.

Preferably, the positive tab and the negative tab of the battery cell are approximately coplanar with the first side surface of the battery cell, two avoidance grooves are arranged on one side of the baffle plate, which is matched with the first side surface, and the two avoidance grooves are respectively arranged at the positions of the positive tab and the negative tab; and the end cover is provided with a pole piece hole at the position of each avoidance groove, and the two negative pieces are fixed in the pole piece holes respectively.

Preferably, when the connecting assembly is matched with at least two battery cells, the positive electrode lug and the negative electrode lug of each adjacent battery cell are arranged at intervals, at least two negative plates connected with the negative electrode lug and at least two negative plates connected with the positive electrode lug are respectively connected through transverse plates, the pole pieces are connected with the transverse plates, and the two transverse plates are insulated and separated through partition plates.

Preferably, the pole piece is fixed on the end cover by injection molding, and a plurality of stress holes are respectively formed in the positions where the pressing plate and the pole piece are connected with the bottom plate.

The invention provides a lithium battery, which is characterized in that: the battery cell packaging structure comprises at least two connecting assemblies, wherein at least one battery cell, a cover plate assembly and a shell, wherein the cover plate assembly is connected with the at least two connecting assemblies;

the one end of casing is uncovered and is set up, and at least two can regular spread with at least one electric core complex coupling assembling and place in the casing, the apron subassembly include with the open end complex apron of casing with set up in two utmost point posts of apron surface, two utmost point posts pass the apron and are connected respectively with two at least coupling assembling's homopolar pole pieces.

The positive pole lug and the negative pole lug of at least one battery cell are connected in parallel through the connecting assembly and then led out to form the positive pole piece and the negative pole piece, the pole pieces are directly fixed with the end cover, a connecting sheet, a protection sheet and other sheet bodies are not needed in the whole structure, the influence of a plurality of sheets and a few sheets on the equipment utilization rate during sheet taking is prevented, at least two connecting assemblies are regularly arranged and then placed in the shell according to needs, the positive pole piece and the negative pole piece are respectively connected in parallel through the cover plate and then connected with the pole posts, the shell is packaged through the cover plate, the two pole posts are used as the electrodes of the whole battery, the stop frame structure is not needed any more, the assembly process is simplified, when the pole pieces are assembled by the cover plate assembly, the pole posts are already fixed in the connecting assembly, and the pole posts cannot be inserted due to the action of the pole pieces.

Preferably, at least two connecting assemblies matched with the battery cell are arranged along the thickness direction of the battery cell, the pole pieces of the connecting assemblies are respectively arranged into two rows according to the polarity, and two pole posts respectively penetrate through the insulating cover plate and are respectively welded and fixed with the pole pieces.

Preferably, the surface of the cover plate is further provided with a liquid injection hole and an explosion-proof valve, and the surface of the end cover is further provided with a soaking hole for electrolyte to pass through.

The invention also provides an assembly method of the lithium battery, which comprises the following steps,

a: arranging at least one battery cell according to requirements, and respectively welding and fixing the positive electrode lug and the negative electrode lug with the two bottom plates of the connecting assembly;

b: covering an end cover on the end face of the arranged battery cell, which is provided with the lugs;

c: welding and fixing the two pole pieces of each connecting assembly with the two pole posts respectively;

d: turning the battery cell relative to the pole piece to enable the end cover to be attached to the cover plate, and enabling the battery cells to be closely arranged;

e: placing the cover plate assembly, the connecting assembly matched with the cover plate assembly and the battery core into a shell, and connecting the cover plate and the shell;

the assembly sequence is A-B-C-D-E or A-B-D-C-E.

The connecting assembly of the battery core, the lithium battery and the assembling method provided by the invention have the advantages that: the negative plate and the pole piece are connected together, the pole piece and the pole lug of the battery cell are conveniently fixed, the pole piece and the negative plate are directly fixed on the connecting assembly, the connecting assembly is directly operated integrally during assembly, the pole piece and the connecting sheet which are separately arranged do not need to be frequently sucked, equipment shutdown caused by multiple pieces and lacking pieces is reduced, and the utilization rate is improved. At least two connecting assemblies are regularly arranged and then are placed in the shell according to needs, positive and negative pole pieces are respectively connected in parallel through the cover plate and then are connected with the pole posts, the shell is packaged through the cover plate, the two pole posts are used as electrodes of the whole battery, a stop frame structure is not needed, the assembly process is simplified, when the pole pieces are assembled by the cover plate assembly, the pole lugs are already fixed in the connecting assemblies, and the pole lugs cannot be inserted due to the action of the pole pieces. When the pole piece overturns, utmost point ear welded fastening has accomplished, and in addition the restriction of apron can not lead to utmost point ear to the inside interpolation that inclines of electric core because of the pole piece that overturns, is provided with the stress intensity when stress hole can reduce the upset on the pole piece simultaneously, further avoids utmost point ear interpolation to protect electric core.

1. In the traditional lithium battery assembling method, the connecting sheet and the protection sheet are separately designed, so that the equipment action is complex, the phenomena of sucking a plurality of sheets, lacking sheets and the like frequently occur in the feeding process of the connecting sheet and the protection sheet, and the manufacturing utilization rate is reduced; the positioning precision of the two on the pole lugs is difficult to ensure, the ultrasonic welding quality is poor and the effective improvement is difficult; according to the invention, the lug is directly fixed on the end cover by injection molding, so that the problems can be effectively solved, the positioning is more convenient, and the feeding mode is simpler.

2. In the traditional lithium battery assembling method, when the battery cores are combined, the tabs are easy to be inserted into the battery core body to cause battery short circuit, and the connecting sheet is easy to damage the tabs of the battery cores when being bent. When the positive and negative electrode lugs are fixed, the positive and negative electrode lugs are fixed through the pressing plate, and the lugs are easy to form and fix, so that the risk of interpolation is avoided; when the pole piece is bent, the pole lugs are firmly fixed, and the pole piece cannot be damaged.

3. In the traditional lithium battery assembly method, after laser welding of the connecting piece is completed, the locking frame needs to be buckled, so that the manufacturing process is complex, various processes such as caching, feeding, buckling height detection and the like of the locking frame are involved, and the buckling quality is difficult to guarantee. The end cover can serve as a stopping frame at the position, so that dust generated during laser welding of the pole piece can be prevented from entering the battery cell, the manufacturing process is simpler, and the production efficiency is improved.

4. The invention can be compatible with various assembly processes and has good adaptability to the parallel assembly of any multiple electric cores.

Drawings

Fig. 1 is an assembly schematic diagram of a connection assembly and a battery cell provided in embodiment 1 of the present invention;

fig. 2 is a schematic diagram of a battery cell provided in embodiment 1 of the present invention;

fig. 3 is a schematic view of a connection assembly according to embodiment 1 of the present invention;

fig. 4 is a schematic end cap view of a connection assembly provided in embodiment 1 of the present invention;

fig. 5 is a schematic diagram of a pole piece of the connection assembly provided in embodiment 1 of the present invention;

fig. 6 is a sectional view of a connecting assembly provided in embodiment 1 of the present invention;

fig. 7 is a schematic diagram of a welding state of a battery cell and a connection assembly according to embodiment 1 of the present invention;

fig. 8 is a schematic diagram of a cell and a connection assembly provided in embodiment 1 of the present invention after being assembled;

fig. 9 is a schematic view of a matching state of a connection assembly and a plurality of battery cells according to embodiment 2 of the present invention;

fig. 10 is a schematic diagram of a pole piece of the connection assembly provided in embodiment 2 of the present invention;

fig. 11 is a schematic diagram of a cell and a connection assembly provided in embodiment 2 of the present invention after being assembled;

fig. 12 is a schematic structural diagram of a lithium battery provided in embodiment 3 of the present invention;

fig. 13 is an assembly view of a cover plate assembly and a connecting assembly of a lithium battery according to embodiment 3 of the present invention;

fig. 14 is an assembled perspective view of a cover plate assembly and a connecting assembly of a lithium battery according to embodiment 3 of the present invention;

fig. 15 is a schematic view of a completed assembled state of a cover plate assembly and a connecting assembly of a lithium battery according to embodiment 3 of the present invention.

Detailed Description

To make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention are described below in detail and completely with reference to the accompanying drawings, and it is apparent that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Referring to fig. 1, the present embodiment provides a connection assembly for a battery cell, which includes an end cap 201 capable of being fastened to one end of at least one battery cell 10, and referring to fig. 2, the end of the battery cell 10 covered by the end cap 201 has a positive tab 101 and a negative tab 102, two pole pieces 202 are disposed on the outer side of the end cap 201, the pole pieces 202 are connected to a bottom sheet 2021 located on the inner side of the end cap 201, and the bottom sheet 2021 can be welded and fixed to the positive tab 101 or the negative tab 102.

In the embodiment, the negative plate 2021 and the pole piece 202 are connected together, so that the pole piece 202 and the pole lug of the battery cell 10 can be conveniently fixed, the pole piece 202 and the negative plate 2021 are directly fixed on the connecting assembly, and the connecting assembly is directly operated integrally during assembly without frequently absorbing the separately arranged pole piece and connecting piece, so that equipment shutdown caused by multiple pieces and lacking of pieces is reduced, and the utilization rate is improved.

Referring to fig. 3, at least one side of the base sheet 2021 is provided with a pressing plate 2023 capable of being turned over on the base sheet 2021, and the positive tab 101 or the negative tab 102 is clamped between the pressing plate 2023 and the base sheet 2021 and welded and fixed. Therefore, the connection strength of the pole lug and the pole piece 202 is improved, and the quality of the battery is improved.

In this embodiment, the structure of the connection assembly 20 is described by taking the connection assembly 20 and one battery cell 10 as an example, referring to fig. 2, when the connection assembly is not assembled, the positive tab 101 and the negative tab 102 of the battery cell 10 are disposed in a coplanar manner, specifically, the positive tab 101 and the negative tab 102 are substantially coplanar with one side surface of the battery cell 10, which is defined as a first side surface.

With reference to fig. 3 and 4, the end cover 201 has the same end profile as the end face of the battery cell 10, a baffle 203 perpendicular to the end cover 201 is further disposed on the periphery of the end cover 201, the end cover 201 is matched with the end face of the battery cell 10, the battery cell 10 is surrounded and wrapped by the baffle 203, so that the connecting assembly 20 is sleeved on the end of the battery cell 10, the end cover 201 and the baffle 203 are insulators, and the pole piece 202 is made of a metal conductive material.

Baffle 203 and first side complex one side are provided with two and dodge groove 204, two dodge groove 204 and set up respectively in anodal ear 101 and negative pole ear 102 position, be provided with utmost point piece hole 205 respectively in every position of dodging groove 204 on the end cover 201, two film 2021 is fixed in utmost point piece hole 205 respectively.

Referring to fig. 5, a row of stress holes 2024 is formed at the edge where the pole piece 202 is connected to the bottom plate 2021, so as to facilitate bending the pole piece 202 relative to the bottom plate 2021; at least one side of the bottom plate 2021 adjacent to the pole piece 202 is connected with the pressing plate 2023, and one side of the pressing plate 2023 connected with the bottom plate 2021 is also provided with a plurality of stress holes 2024 along the length direction, referring to fig. 6, the bottom plate 2021 is fixed in the end cover 201 by injection molding, so that the connection can be effectively fixed, and no gap exists after the connection.

The connection mode of the single battery cell 10 and the connection assembly 20 is as follows: referring to fig. 7, the end cap 201 is disposed substantially perpendicular to the end face of the battery cell 10, the positive tab 101 and the negative tab 102 pass through the avoidance groove 204 and then contact the negative plate 2021, the pressing plate 2023 on one side or both sides of the negative plate 2021 is turned over to press the positive tab 101 or the negative tab 102, and then is welded and fixed by laser welding or ultrasonic welding, and when the pressing plate 2023 is disposed on one side, the area of the pressing plate 2023 needs to be increased appropriately to ensure the pressing effect. After welding, the battery cell 10 and the end cap 201 are turned over relatively, so that the end cap 201 is pressed on the end surface of the battery cell 10, and the baffle plate 203 is clamped on the side surface of the battery cell 10; it should be noted that, after the positive tab 101 and the negative tab 102 are welded, the welding position is a certain distance away from the avoiding groove 204, so that the end of the battery cell 10 can pass over the baffle 203 and then be inserted into the baffle 203 along the axial direction. The structure shown in fig. 8 is obtained after the connecting assembly 20 is connected with the battery cell 10, and the connecting assembly 20 and the battery cell 10 after being matched can be further connected by sticking the insulating tape 30, so as to prevent falling off. In this embodiment, the tab and the base plate 2021 are welded and fixed and then turned over to match the end of the end cap 201 with the end of the battery cell 10, so that the connection effect between the tab and the pole piece 202 is not affected during the bending and turning process, which is convenient for operation.

Example 2

In this embodiment, the structure of the lithium battery is described by taking the connection assembly 20 and two battery cells 10 as an example, and referring to fig. 9, when connecting a plurality of battery cells 10, positive electrode tabs 101 and negative electrode tabs 102 on the plurality of battery cells 10 are arranged in a coplanar manner, in this embodiment, the plurality of battery cells 10 are arranged along the length direction, the width of the end cap 201 is not changed, the length is extended to be able to accommodate two battery cells 10, and the structure of the end cap 201 is substantially the same as the end surface of the arranged battery cells 10. The end cover 201 is provided with a pole piece hole 205 at the position of each pole lug, a bottom piece 2021 is fixed in each pole piece hole 205, and the positive pole lug 101 and the negative pole lug 102 of the adjacent cell 10 are arranged at intervals;

with reference to fig. 10, the bottom plates 2021 connected to the homopolar tabs are respectively connected by two cross pieces 2025, the pole pieces 202 are fixedly connected to the cross pieces 2025, the plurality of battery cells 10 are connected in parallel and then connected to the two pole pieces 202, and the two cross pieces 2025 are isolated and separated by a separator (not shown).

The connection mode of the battery cell 10 and the connection assembly 20 is the same as that in embodiment 1, the tabs are pressed on the bottom sheet 2021 through the pressing plate 2023, and after welding and fixing, the end cover 201 or the battery cell 10 is integrally turned over, so that the end face of the battery cell 10 is matched with the end cover 201, referring to fig. 11, and after assembly, the battery cell 10 and the end cover 201 can be fixed by adhering an insulating tape 30.

Example 3

The present embodiment further provides a lithium battery based on the connection assembly provided in the above embodiments, referring to fig. 12, including a cover plate assembly 70, a housing 80, a connection assembly 20, and a battery cell 10, where one end of the housing 80 is open, at least two connection assemblies 20 matched with at least one battery cell 10 can be regularly arranged and placed in the housing 80, the cover plate assembly 70 includes a cover plate 701 matched with the opening of the housing 80 and two terminals 702 arranged on the outer surface of the cover plate 701, and the terminals 702 can penetrate through the cover plate 701 and be connected with the homopolar pole pieces 202 of at least two connection assemblies 20 respectively.

In the embodiment, the positive tab 101 and the negative tab 102 of at least one electrical core 10 are connected in parallel by the connecting assembly 20 and then led out to form the positive and negative pole pieces 202, the whole structure does not need to use a connecting sheet, a protective sheet and other sheets, thereby preventing the influence of multiple sheets and less sheets on the equipment utilization rate, at least two connecting assemblies 20 are regularly arranged and then placed in the shell 80 according to needs, the positive and negative pole pieces 202 are respectively connected in parallel by the cover plate 70 and then connected with the pole posts 702, the shell 80 is packaged by the cover plate 701, two pole posts 702 are used as the electrodes of the whole battery, no stop frame structure is needed, the assembly process is simplified, when the pole pieces 202 are assembled by the cover plate assembly 70, the pole posts are already fixed in the connecting assembly 20, and the pole posts cannot be inserted into the pole posts due to the action of the pole pieces 202.

The assembly method of the lithium battery comprises the following steps:

a: the positive tab 101 and the negative tab 102 of at least one battery cell 10 are respectively welded and fixed with the two pole pieces 202 of the connecting assembly 20;

b: covering an end cover 201 on an end face of at least one battery cell 10 provided with a tab;

c: welding and fixing the two pole pieces 202 of each connecting assembly 20 with the two pole posts 702 respectively;

d: turning over the battery cell 10 relative to the pole piece 202 to make the end cover 201 fit with the cover plate 701, and tightly arranging the battery cells 10;

e: placing the cover plate assembly 70, the connecting assembly 20 matched with the cover plate assembly 70 and the battery core into the shell 80, and connecting the cover plate 801 with the shell 80;

the assembly sequence is A-B-C-D-E or A-B-D-C-E.

When the assembly sequence is a-B-C-D, the pole piece 202 and the end cap 201 are in a substantially vertical state when not welded, the pole piece 202 and the pole post 702 are first placed together, the pole piece 202 is welded by laser welding or ultrasonic welding, after the pole piece 202 and the pole post 702 are fixed, the cover plate 701 is turned over relative to the battery cell 10, so that the cover plate 701 covers the end cap 201, then the two pole pieces 202 of the next connecting assembly 20 are respectively welded with the pole post 702 by the method of step C, at this time, it is necessary to pay attention to that the polarity of the pole post 702 is determined, the pole piece 202 and the pole post 702 with the same polarity are welded and fixed, then the battery cell 10 is turned over to make the cover plate 701 cover the end cap 201, and the battery cells 10 welded at the back are sequentially arranged and fixed with the battery cells 10 welded before, or after a plurality of battery cells 10 are welded, the battery cells 10 are sequentially turned over and arranged, and the arranged in the casing 80 after the welding is completed, and then the cover plate 701 and the shell 80 are welded and fixed, wherein the shell 80 is preferably an aluminum shell.

When the assembly sequence is A-B-D-C, firstly, arranging a plurality of connecting assemblies 20 to enable positive and negative pole pieces to be arranged in two rows, enabling the pole pieces 202 to be in close contact with the end cover 201 at the moment, then pressing the cover plate 701 on the arranged pole pieces 202, welding the outer side surface of the cover plate 701 in a laser welding or ultrasonic welding mode to enable the pole posts 702 below the cover plate 701 to be fixedly connected with the pole pieces 202, plugging the arranged battery cell 10 into the shell 80 after welding is completed, and then welding and fixing the cover plate 701 and the shell 80.

In this embodiment, a structure of a lithium battery is described by taking an example in which one battery cell 10 is fixed by one connecting assembly 20 provided in embodiment 1, where two connecting assemblies 20 assembled with the battery cell 10 are provided in a casing 80, and the assembling steps are a-B-C-D-E, and specifically include the following steps:

a: referring to fig. 1, the positive tab 101 and the negative tab 102 of the battery cell 10 respectively pass through the avoidance groove 204 to contact the base sheet 2021, referring to fig. 7, the pressing sheet 2023 is turned over and pressed on the tabs on the two sides, and the tabs are fixed on the surface of the pressing sheet 2023 by laser welding;

b: referring to fig. 8, the welded battery cell 10 is turned over relative to the end cap 201 and inserted into the end cap 201, so that the tabs are bent relative to the battery cell 10 and are accommodated in the end cap 201, and the battery cell 10 and the connecting assembly 20 are attached and connected by the insulating tape 30;

c: with reference to fig. 13 and 14, the covering surface of the cover plate 701 is prevented from facing upward, two connecting assemblies 20 assembled with the battery cell 10 are respectively disposed on two sides of the cover plate 701, so that the pole pieces 202 are disposed on the pole posts 702, the pole pieces 202 with the same polarity are matched with the same pole post 702, and then the four pole pieces 202 are respectively welded on the pole posts 702;

d: referring to fig. 15, the cover plate 701 is kept still, the battery cells 10 on both sides are respectively turned over, so that the pole piece 202 is turned over to the upper surface of the end cover 201, the end cover 201 is attached to the surface of the cover plate 701, the two battery cells 10 are closely arranged, and at this time, the two battery cells 10 can be bonded together by the binding tape 40;

when the pole piece 202 is turned over, the tab is welded and fixed, and due to the limitation of the cover plate 2023, the tab cannot be obliquely inserted into the battery cell 10 due to the fact that the pole piece 202 is turned over, and meanwhile, the stress hole 2024 formed in the pole piece 202 can reduce the stress intensity during turning over, so that the tab is further prevented from being inserted, and the battery cell 10 is protected;

e: after the assembly is completed, the cover plate assembly 70 and the plurality of battery cells 10 fixed thereon are inserted into the casing 80, and the cover plate 701 is covered on the open end of the casing 80 and welded and fixed.

Referring to fig. 15, the surface of the cover plate 701 is further provided with an explosion-proof valve 703 and a liquid injection hole 704, and in combination with fig. 4, the end cover 201 is further distributed with a plurality of wetting holes 206 through which the electrolyte flows.

If the battery cell is assembled according to the sequence of a-B-D-C-E, the pole pieces 202 can be firstly turned over and attached to the end cover 201, then the cover plate 701 covers the end cover 201, the outer side of the cover plate 701 is welded to realize the connection between the pole 702 positioned on the inner side and the pole piece 202, if more connecting assemblies 20 need to be fixed, each pole piece 202 and the corresponding pole 702 can be welded in sequence by analogy, then the battery cell 10 is turned over in sequence, or the pole pieces 202 are firstly turned over and the end cover 201 are firstly turned over, the cover plate 701 is covered on the end cover 201 after the battery cells 10 are arranged, then the welding is carried out, if the number of the connecting assemblies 20 is large, the length of the pole 702 needing to be adapted to be positioned on the inner side of the cover plate 701 is adjusted, and therefore the battery cells connected by the connecting assemblies 20 are connected into the pole 702 in parallel. Therefore, the assembly of any number of connecting assemblies 20 can be realized, and the problem of inserting the lug does not exist.

For the case that one connecting assembly 20 provided in embodiment 2 fixes two battery cells 10 or more battery cells 10, the assembling manner of the lithium battery is the same as that of this embodiment, that is, after the connecting assembly 20 is assembled, the assembly of the lithium battery is only the assembling relationship between the cover plate assembly 70 and the connecting assembly 20, and the number of the battery cells 10 is not affected.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A connection assembly for a battery cell, characterized in that: it comprises an end cover that can be fastened to one end of at least two battery cells, the end cover of the battery cell covered by the end cover has a positive electrode ear and a negative electrode ear, and the end cover Two pole pieces are arranged on the outside, and the pole pieces are connected with the bottom piece on the inner side of the end cover, and the bottom piece can be welded and fixed with the positive electrode lug or the negative electrode lug;

At least one side of the bottom sheet is provided with a pressing plate that can be turned over on the bottom sheet, and the positive electrode ear or the negative electrode lug is clamped between the pressing plate and the bottom sheet and welded and fixed;

When the connecting assembly is matched with at least two battery cells, the positive electrode tabs and the negative electrode tabs of the adjacent battery cells are arranged at intervals, and the at least two bottom sheets connected to the negative electrode tabs and the at least two bottom sheets connected to the positive electrode tabs are respectively connected by horizontal sheets, so that the The pole piece is connected with the horizontal piece, and the two horizontal pieces are separated by a separator insulation.

2 . The connection assembly of a battery cell according to claim 1 , wherein the end cover is roughly the same as the end face contour of the at least two battery cells after being arranged, and the periphery of the end cover is also provided with a vertical end cover stopper. 3 . The plate, the end caps are matched with the end faces of the arranged battery cells, the arranged battery cores are enclosed and wrapped by a baffle plate, and the end caps and the baffle plates are both insulators.

3 . The connection assembly of a battery cell according to claim 2 , wherein the positive electrode tab and the negative electrode tab of the battery cell are substantially coplanar with the first side surface of the battery cell, and the baffle plate and the first side surface are substantially coplanar. 4 . The matching side is provided with two avoidance grooves, and the two avoidance grooves are respectively arranged at the positions of the positive electrode lug and the negative electrode lug; the end cover is respectively provided with a pole piece hole at the position of each avoidance groove, and the two Each of the bottom sheets is respectively fixed in the pole piece holes.

4 . The connection assembly of a battery cell according to claim 1 , wherein the pole piece is injection-molded and fixed on the end cover, and a plurality of stress holes are respectively provided at the positions where the pressure plate and the pole piece are connected to the bottom piece. 5 .

5. A lithium battery using the connection assembly according to any one of claims 1 to 4, characterized in that it comprises at least two connection assemblies, at least two battery cells are fixed on the connection assemblies, and the at least two connection assemblies are connected The cover plate assembly, and the casing that encapsulates the cell;

One end of the casing is open, and at least two connecting assemblies matched with at least two electric cores can be placed in the casing in a regular arrangement. The cover plate assembly includes a cover plate matched with the open end of the casing and a The two poles on the outer surface of the cover plate are respectively connected to the same pole pieces of the at least two connection components through the cover plate.

6 . The lithium battery according to claim 5 , wherein the at least two connecting components matched with the battery cells are arranged along the thickness direction of the battery cells, and the pole pieces of the connecting components are arranged in two rows according to the polarity. 7 . , the two poles are respectively welded and fixed through the insulating cover plate and the pole piece.

7 . The lithium battery according to claim 5 , wherein the surface of the cover plate is further provided with a liquid injection hole and an explosion-proof valve, and the surface of the end cap is further provided with an infiltration hole for the electrolyte to pass through. 8 .

8. The assembling method of the lithium battery according to any one of claims 5-7, characterized in that: comprising:

A: Arrange at least two cells as required, and weld the positive and negative tabs to the two negatives of the connecting assembly respectively;

B: Cover the end caps on the end faces of the arranged cells with tabs;

C: Weld and fix the two pole pieces of each connection component to the two pole posts respectively;

D: Flip the cell relative to the pole piece to make the end cover fit with the cover plate, and the cells are closely arranged;

E: Put the cover plate assembly and its matching connection components and cells into the casing, and connect the cover plate and the casing;

Assembly sequence is A-B-C-D-E or A-B-D-C-E.