CN215578962U

CN215578962U - Utmost point ear structure, electric core monomer and battery module

Info

Publication number: CN215578962U
Application number: CN202121093191.2U
Authority: CN
Inventors: 梁明岗; 江辉; 邹美靓; 王耐清
Original assignee: Evergrande New Energy Technology Shenzhen Co Ltd
Current assignee: Evergrande New Energy Technology Shenzhen Co Ltd
Priority date: 2021-05-20
Filing date: 2021-05-20
Publication date: 2022-01-18
Anticipated expiration: 2031-05-20

Abstract

The utility model is suitable for the field of power batteries, and provides a tab structure, a single battery cell and a battery module. The tab structure comprises a leading-out part, a bonding part and a welding part which are connected in sequence, wherein the leading-out part is used for being connected with an external structure, tab glue is attached to the bonding part, and the welding part is used for being welded with a connecting part of a single battery cell; the welding part is including connecting the first linkage segment of connecting portion and connecting the second of first linkage segment links the section, first linkage segment with the second links the section and is located respectively the both sides of connecting portion and all with connecting portion welding. The tab structure provided by the utility model can effectively solve the problem of welding crack of the metal conducting strip under the condition that the welding part is connected with the single surface of the connecting part, improves the welding reliability of the single battery cell and reduces the manufacturing cost.

Description

Utmost point ear structure, electric core monomer and battery module

Technical Field

The utility model belongs to the field of power batteries, and particularly relates to a tab structure, a single battery cell and a battery module.

Background

The soft package lithium ion battery has the characteristics of simple structure, randomly changeable shape, high energy density and the like, the application field is wider and wider, and the market demand is higher and higher. The battery module is the core part of the soft package lithium ion battery. The battery module comprises a plurality of battery cell monomers, and the battery module is expanded and decompressed through series-parallel connection between the battery cell monomers. The battery cell monomer comprises a battery cell body and a tab structure. The battery cell body is connected with the lug structure in a welding mode through the convex connecting portion of the battery cell body, and the lug structure is used for being connected with an external structure or an adjacent battery cell monomer. The tab structure comprises a metal conducting sheet and tab glue coated on the metal conducting sheet. The metal conducting strip is the slice, and the positive pole or the negative pole of naked electric core are connected through connecting portion to one end, and one end and exterior structural connection.

Along with the promotion of electric core monomer energy density, the battery producer causes the problem that metal conducting strip welds and splits because of welding power is big easily when utmost point ear structure and electric core body welding, influences utmost point ear and overflows and the free reliability of electric core, welds the problem of splitting in order to solve through increasing the welding screening glass in the trade at present, but the corresponding manufacturing cost that has increased.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome the defects of the prior art and provides a tab structure, a single battery cell and a battery module, aiming at solving the problem of the welding reliability of the tab structure and the single battery cell.

In order to achieve the above purpose, the embodiment of the present invention provides the following technical solutions:

the tab structure comprises a leading-out part, a bonding part and a welding part which are connected in sequence, wherein the leading-out part is used for being connected with an external structure, tab glue is attached to the bonding part, and the welding part is used for being welded with a connecting part of a single battery cell; the welding part is including connecting the first linkage segment of connecting portion and connecting the second of first linkage segment links the section, first linkage segment with the second links the section and is located respectively the both sides of connecting portion and all with connecting portion welding.

Through adopting above-mentioned technical scheme, when weld part and connecting portion welded, first linkage segment and second were even a section centre gripping connecting portion to as the deformation that spacing face each other restricted first linkage segment and second even section each other, thereby can effectively solve the problem that the metal conducting strip welds and splits under weld part and the connecting portion single face condition of being connected, improve electric core monomer welded reliability. Meanwhile, as the protection sheet does not need to be additionally placed and fixed in the welding process, the problems of inconvenient operation and improved production caused by the addition of the protection sheet can be avoided.

Optionally, the welding portion is folded in half to form the first connecting section and the second connecting section.

By adopting the technical scheme, the first connecting section and the second connecting section are formed in a metal sheet folding mode, so that the connecting operation between two independent parts is omitted, and the manufacturing cost is reduced. The metal sheet is folded in half to form the first connecting section and the second connecting section by utilizing the ductility of the metal sheet, so that the operation is simple and convenient.

Optionally, the welding portion is centrally folded in half to form the first connecting section and the second connecting section.

Through adopting above-mentioned technical scheme, first linkage segment and the continuous section fifty percent discount of second and press from both sides connecting portion and establish it in, first linkage segment and second are even the width of section in the left and right directions the same for the area of contact of front and back surface and the first linkage segment of connecting portion, the area of contact of the back surface and the second of connecting portion are even the section the same. This setting can effectively avoid the thickness difference that brings because the length difference and then the electric core monomer safety problem that leads to.

Optionally, the first connecting section and the second connecting section can completely cover two side surfaces of the connecting part.

Through adopting above-mentioned technical scheme, make electric core monomer equal at connecting portion position and along width direction's thickness to further ensure electric core monomer safety.

Optionally, the thickness of the lead-out portion is greater than that of the bonding portion.

By adopting the technical scheme, firstly, the internal resistance of the tab structure can be reduced, the heat production condition of the tab structure is improved, and the service life of the tab structure is prolonged; secondly, the leading-out part is thickened while the bonding part maintains the original thickness, so that the influence of the integral thickening of the tab structure on the packaging effect of the aluminum-plastic film can be avoided, and the risk of liquid leakage is reduced; finally, the lead-out part is thickened, so that the integral rigidity of the tab structure can be improved, and the deformation condition of the tab structure in production can be improved.

Optionally, the thickness of the leading-out part is-times of the thickness of the bonding part.

Through adopting above-mentioned technical scheme, can effectively improve the heat production condition of utmost point ear structure when guaranteeing the encapsulation effect of plastic-aluminum membrane in the junction of splicing.

Optionally, the width of the welding portion is greater than the width of the bonding portion.

Through adopting above-mentioned technical scheme, the weld part is the welding position of electric core monomer structure and connecting portion, increases the width of weld part and connecting portion to increase the welding seal area, reduce the ohmic internal resistance of welding department, improve utmost point ear structure temperature rise problem. In addition, the connection part is widened, so that the current density distribution from the battery cell body to the lug structure can be improved, and the service life of the battery cell monomer is prolonged.

The second aspect provides an electric core monomer, including electric core body, connecting portion and utmost point ear structure, connecting portion protrusion in electric core monomer and with utmost point ear structure is connected, utmost point ear structure is as above-mentioned utmost point ear structure.

By adopting the technical scheme, the problem of welding cracks of the metal conducting strips under the condition that the welding part is connected with the single surface of the connecting part can be effectively solved, the reliability of welding of the electric core monomer is improved, and the manufacturing cost is reduced.

Optionally, the widths of the welding portion and the connecting portion are both 0-30mm smaller than the width of the battery cell body.

Through adopting above-mentioned technical scheme, the welding part the internal face of connecting portion and the module shell that corresponds forms a mounting gap, and the mounting gap is used for supplying assembly accessories such as connecting wire, sampling line and busbar in the module shell to install to the inner space of more reasonable utilization module shell improves battery module's energy density. The difference value between the welding part and the connecting part and the battery cell body is 0-30mm, and the size selection can give consideration to the requirements of widening to improve the current density distribution of the battery cell monomer and the requirements of avoiding to arrange in a reasonable assembling space.

In a third aspect, a battery module is provided, which includes the above battery cell.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic view of a conventional tab structure;

fig. 2 is a schematic diagram of a cell body and a connection portion;

fig. 3 is a schematic diagram of a cell unit adopting a conventional tab structure, which is a top view;

fig. 4 is a schematic diagram of a cell unit adopting a conventional tab structure, which is a front view;

fig. 5 is a first schematic view of a tab structure provided in an embodiment of the present invention, wherein a welding portion is folded in half in a use state;

fig. 6 is a second schematic view of a tab structure according to an embodiment of the present invention, wherein the welding portion is not folded;

fig. 7 is a schematic diagram of a battery cell using a tab structure provided in an embodiment of the present invention, which is a top view;

fig. 8 is a partial schematic view of a battery cell using a tab structure provided in an embodiment of the present invention, which is a front view.

Wherein, in fig. 1 to 4, the respective reference numerals:

10', a tab structure; 121' of tab glue; 20. a connecting portion; 30. a cell body;

respective reference numerals in fig. 5 to 8:

10. a tab structure; 11. a lead-out section; 13. welding the part; 131. a first segment; 132. a second connecting section; 121. gluing a tab; 20. a connecting portion; 30. the battery cell comprises a battery cell body.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, as used herein, refer to an orientation or positional relationship indicated in the drawings, which is solely for the purpose of facilitating the description and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and is therefore not to be construed as limiting the utility model.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

With reference to the drawings, the tab structure 10 provided in the present application, and a battery cell and a battery module using the tab structure 10 will now be described in an exemplary manner.

The battery cell unit includes a battery cell body 30, a tab structure 10, and a connecting portion 20 connecting the battery cell body 30 and the tab structure 10. Referring to fig. 2, in general, the cell body 30 includes a bare cell formed by winding or laminating a positive electrode sheet, a negative electrode sheet and a separator, and an aluminum plastic film wrapped outside the bare cell. Connecting portion 20 has two, uses the figure as an example, and two connecting portions 20 are located naked electric core length direction's both sides for connect utmost point ear structure 10. The tab structure 10 is divided into a positive tab and a negative tab according to functions, wherein in the two connecting portions 20, one connecting portion 20 is connected with a positive plate and a positive tab of a battery cell, and the other connecting portion 20 is used for connecting a negative plate and a negative tab.

Fig. 1 shows a tab structure 10' of the prior art, and fig. 3 and 4 show a structural schematic of a cell unit using the tab structure 10. The complete tab structure 10' mainly consists of a tab glue 121 and a metal conductive sheet. The metal conductive sheet is rectangular sheet, one end of the metal conductive sheet is connected with the connecting part 20 by welding, and the other end of the metal conductive sheet is used for connecting an external structure. The metal conducting sheet of the cathode lug is a copper sheet or a copper nickel-plated sheet, the metal conducting sheet of the anode lug is a pure aluminum sheet, and the thickness range is usually between 0.2mm and 0.5 mm. The tab glue 121' is an insulated part on the tab structure 10, and is disposed at a connection position of the metal conductive sheet and the aluminum plastic film. Its effect prevents to take place the short circuit between strap and the plastic-aluminum membrane when naked electric core encapsulation to accessible heating and plastic-aluminum membrane hot melt are sealed to be bonded together when the encapsulation, play the effect that prevents the weeping.

Referring to fig. 4, the conventional tab structure 10' is welded to the connection portion 20 after being overlapped, so as to fixedly connect the tab structure 10 to the connection portion 20. Along with the improvement of the energy density of the battery cell monomer, correspondingly, the welding power of the tab structure 10', especially the negative tab, is increased, so that the problem of welding crack of the metal conducting strip is easily caused. Some manufacturers add a protection sheet on the other side of the tab structure 10' away from the connection portion 20, and provide a limiting surface during welding to solve the above problems, but at the same time, the operation is inconvenient and the manufacturing cost is increased

Referring to fig. 5 to 8, the tab structure 10 provided in this embodiment includes a lead-out portion 11, an adhesive portion and a welding portion 13, which are connected in sequence, wherein the lead-out portion 11 is used for connecting with an external structure, the adhesive portion is attached with a tab glue 121 (in the drawings, the position covered by the tab glue 121 is the adhesive portion), and the welding portion 13 is used for welding with the connection portion 20 of the cell unit.

The welding part 13 includes a first connection segment 131 connected to the connection part 20 and a second connection segment 132 connected to the first connection segment 131, and the first connection segment 131 and the second connection segment 132 are respectively located at two opposite sides of the connection part 20 and are welded to the connection part 20 of the cell unit.

For convenience of description, the longitudinal direction of the cell body 30 is defined as the up-down direction, the width direction of the cell body 30 is defined as the left-right direction, and the thickness direction of the cell body 30 is defined as the front-rear direction. The lead portion 11, the adhesive portion, and the welded portion 13 are connected in this order from top to bottom: the lead portion 11 is located above the adhesive portion, and the adhesive portion is located above the welded portion 13.

Referring to fig. 8, the first connecting section 131 and the second connecting section 132 are respectively located on two opposite side surfaces (a front surface and a rear surface) of the connecting portion 20, and are welded to the connecting portion 20. When the welding part 13 is welded with the connecting part 20, the first connecting section 131 and the second connecting section 132 clamp the connecting part 20 and are mutually used as limiting surfaces to limit the deformation of the first connecting section 131 and the second connecting section 132, so that the problem of welding cracks of the metal conducting strips under the condition that the single surfaces of the welding part 13 and the connecting part 20 are connected can be effectively solved, and the welding reliability of the cell monomer is improved. Meanwhile, as the protection sheet does not need to be additionally placed and fixed in the welding process, the problems of inconvenient operation and improved production caused by the addition of the protection sheet can be avoided.

By last, the utmost point ear structure 10 that this embodiment provided to and the electric core monomer and the battery module that adopt this utmost point ear structure 10, can effectively solve the problem that the metal conducting strip welds and splits under the welding part 13 and the 20 single face connection circumstances of connecting portion, improve electric core monomer welded reliability, and reduce manufacturing cost.

In another embodiment of the present application, referring to fig. 6, the welding portion 13 is folded in half along the width direction (left-right direction) of the cell body 30 to form a first connecting segment 131 and a second connecting segment 132. The first connecting section 131 and the second connecting section 132 are made of the same metal sheet, and the first connecting section 131 and the second connecting section 132 are formed in a folding manner, so that the connecting operation between two independent parts is omitted, and the manufacturing cost is reduced. The first segment 131 and the second segment 132 are formed by folding the metal sheet in half by utilizing the ductility of the metal sheet, and the operation is simple. After being folded in half, the first and

second link sections

131 and 132 sandwich the connection portion 20 therebetween, and then are welded.

Preferably, the welding portion 13 is folded in half in the left-right direction to form the first segment 131 and the second segment 132. In other words, the first segment 131 and the second segment 132 have the same width. As shown in fig. 6, the first segment 131 and the second segment 132 have the same width in the left-right direction. The first connecting section 131 and the second connecting section 132 are folded in half and sandwich the connecting portion 20, and the widths of the first connecting section 131 and the second connecting section 132 in the left-right direction are the same, so that the contact area between the front surface and the rear surface of the connecting portion 20 and the first connecting section 131 is the same, and the contact area between the rear surface of the connecting portion 20 and the second connecting section 132 is the same. It can be understood that first linkage 131 and second linkage 132 length are different, and then the battery cell monomer has the different condition of local thickness in the width direction in connecting portion 20 position, and the current appears the great problem of local temperature rise easily when passing through this position, and influences battery cell monomer quality and even threatens battery cell monomer safety in utilization. The first connecting section 131 and the second connecting section 132 have the same length, so that the safety problem of the single battery cell caused by the thickness difference due to the different lengths can be effectively avoided.

Preferably, the first and

second segments

131 and 132 can completely cover both side surfaces of the connection part 20. Here, the covering means that the first segment 131 and the second segment 132 can completely cover the width of the connection portion 20 in the lateral width direction, and the circumferential side of the connection portion 20 and the connection surface of the welding portion 13 are in a closed ring shape. The widths of the first connecting section 131 and the second connecting section 132 are not less than the width of the connecting portion 20, so that the first connecting section 131 and the second connecting section 132 can completely cover the connecting portion 20, and the thicknesses of the single battery cells at the position of the connecting portion 20 and in the width direction are equal, so as to further ensure the safety of the single battery cells. In the actual structure, the widths of the first segment 131 and the second segment 132 may be larger than the width of the connection portion 20, and the first segment 131 and the second segment 132 are bent to protrude and be welded at both ends of the width of the connection portion 20, so that the circumferential side surface of the connection portion 20 is connected to the welding portion 13.

In another embodiment of the present application, referring to fig. 8, the thickness of the lead-out portion 11 is greater than that of the bonding portion. The lead-out part 11 of the tab structure 10 is thickened, and firstly, the lead-out part 11 is thickened, so that the internal resistance of the tab structure 10 can be reduced, the heat generation condition of the tab structure 10 is improved, and the service life of the tab structure 10 is prolonged; secondly, the leading-out part 11 is thickened, the bonding part maintains the original thickness, the adverse effect of the integral thickening of the tab structure 10 on the packaging effect of the aluminum-plastic film can be avoided, and the risk of liquid leakage is reduced; finally, the lead-out part 11 is the exposed part of the tab structure 10, the size is long, the overall strength of the tab structure 10 can be improved by thickening the lead-out part 11, the deformation condition of the tab structure 10 caused by external force in production is improved, and the attractive effect of the structure is improved.

Preferably, the thickness of the lead portion 11 is 2 to 3 times the thickness of the adhesive portion. Through a plurality of experimental tests, the bonding part adopts the thickness of a conventional metal conducting strip (the thickness range is usually between 0.2mm and 0.5 mm), the leading-out part 11 is thickened to be 2 to 3 times of the bonding part, and the heat production condition of the lug structure 10 can be effectively improved while the packaging effect of the aluminum plastic film at the bonding part is ensured. The thickness of the lead-out portion 11 may be set to be 2 times, 2.1 times, 2.3 times, 2.5 times, 2.6 times, 2.7 times, 2.9 times, 3 times, etc. of the adhesive portion by those skilled in the art according to circumstances, and is not limited herein.

In the structure shown in fig. 8, the center line of the lead portion 11 in the thickness direction and the center line of the adhesive portion in the thickness direction are arranged in a collinear manner, and the center lines are both the center lines of the cell units in the front-rear direction. The thickness of the lead-out part 11 is larger than that of the bonding part, and the transition part of the lead-out part 11 and the bonding part can be used as a positioning position of the tab glue 121, so that the coating operation of the tab glue 121 is facilitated. The thickness of the leading-out part 11 is equally thickened in the front-back direction of the battery cell monomer, so that the balanced distribution of current on the two sides of the battery cell monomer in the front-back direction is facilitated.

In another embodiment of the present application, referring to fig. 5, the width of the welding portion 13 is greater than the width of the bonding portion. So that the whole tab structure 10 is in an inverted T shape. The welding portion 13 is a welding position of the tab structure 10 and the connection portion 20, and generally, the welding portion 13 and the connection portion 20 are a welding position of a cell structure. The welded portion 13 has the same width as the connecting portion 20. The widths of the welding part 13 and the connecting part 20 are increased, so that the welding area is increased, the ohmic internal resistance of the welding part of the cell structure can be reduced, and the temperature rise problem of the tab structure 10 is solved. In addition, widening the welding part 13 and the connecting part 20 can also improve the current density distribution from the cell body 30 to the tab structure 10, and prolong the service life of the cell unit.

Preferably, the widths of the welding portion 13 and the connecting portion 20 are smaller than the width of the cell body 30. For convenience of description, the structure in which the welding part 13 and the connection part 20 are welded is referred to as an extension. It can be understood that a plurality of electric core monomers with the size are arranged in order and are placed, and a module shell is wrapped in a matching mode, so that the main body part of the battery module can be formed. The width of extension is less than the 30 widths of electricity core body, and the internal face of extension and the module shell that corresponds forms a mounting gap, and this mounting gap is used for supplying assembly parts such as connecting wire, sampling line and busbar in the module shell to installation to more reasonable utilization module shell's inner space improves the energy density of battery module.

Preferably, the difference between the widths of the extending piece and the cell body 30 is 0-30 mm. The size selection can give consideration to the requirement of widening to improve the distribution of the current density of the battery cell monomer and the requirement of avoiding to rationalize the arrangement of the assembly space. Those skilled in the art can adjust the size of the welding portion 13 according to the width of the cell body 30, and the difference between the widths of the welding portion 13 and the cell body 30 is specifically set to be 5mm, 8mm, 10mm, 12mm, 15mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, and the like, which is not limited herein.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents or improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A tab structure comprises a leading-out part, a bonding part and a welding part which are connected in sequence, wherein the leading-out part is used for being connected with an external structure, tab glue is attached to the bonding part, and the welding part is used for being welded with a connecting part of a single battery cell; the welding part comprises a first connecting section and a second connecting section, wherein the first connecting section is connected with the second connecting section of the connecting part, and the first connecting section and the second connecting section are respectively positioned on two sides of the connecting part and are welded with the connecting part.

2. The tab structure of claim 1 wherein the weld is doubled over to form the first segment and the second segment.

3. The tab structure of claim 1 wherein the weld is centrally folded in half to form the first and second connection segments.

4. The tab structure of claim 1, wherein the first segment and the second segment are capable of completely wrapping both side surfaces of the connection part.

5. The tab structure of claim 1 wherein the lead portion has a thickness greater than the bond portion.

6. The tab structure of claim 5, wherein the lead-out portion has a thickness 2 to 3 times the thickness of the bonding portion.

7. The tab structure of claim 5, wherein the welding portion has a width greater than a width of the bonding portion.

8. An electric core monomer, characterized by, includes electric core body, connecting portion and utmost point ear structure, connecting portion protrusion in electric core monomer and with utmost point ear structure is connected, utmost point ear structure be according to any utmost point ear structure of claims 1 to 7.

9. The cell unit of claim 8, wherein the widths of the welding portion and the connecting portion are each 0-30mm smaller than the width of the cell body.

10. A battery module comprising the cell unit according to claim 8 or 9.