CN115513611B

CN115513611B - Battery cell and battery cell manufacturing method

Info

Publication number: CN115513611B
Application number: CN202211330274.8A
Authority: CN
Inventors: 郑丽; 王浩; 于子龙; 陈杰
Original assignee: Huizhou Liwinon Energy Technology Co Ltd
Current assignee: Huizhou Liwinon Energy Technology Co Ltd
Priority date: 2022-10-27
Filing date: 2022-10-27
Publication date: 2023-06-30
Anticipated expiration: 2042-10-27
Also published as: CN115513611A

Abstract

The invention provides a battery cell and a battery cell manufacturing method, wherein the battery cell comprises a first pole piece, a first tab and first adhesive paper, the first pole piece comprises a first current collector and a first active coating, a first welding groove is limited by a first blank area of the first current collector and the first active coating, the first tab is welded in the first welding groove, the first adhesive paper comprises a first cover part with smaller thickness and a second cover part with larger thickness, the first cover part covers the tab, the second cover part covers the first blank area, the thickness of the first cover part is L1, the thickness of the second cover part is L2, and the thickness of the first tab is L3, so that the battery cell is manufactured by the following steps: l1+l3=l2. According to the battery cell and the battery cell manufacturing method, the flatness of the adhesive paper for protecting the electrode lugs can be improved, and the risk of poor adhesive property of the adhesive paper in the battery cell manufacturing or using process is reduced, so that the safety of the battery cell is improved.

Description

Battery cell and battery cell manufacturing method

Technical Field

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

Background

In the prior art, in order to prevent metal burrs of the electrode lugs from penetrating through the isolating film, the battery cell is usually provided with adhesive paper, and the adhesive paper is adhered to the electrode lugs; in addition, the gummed paper can also prevent lithium from being separated from the area, opposite to the tab, of the negative plate. Specifically, the pole piece of electric core includes electric current body and active coating, and the blank district of electric current body and active coating prescribe a limit jointly to utmost point ear welding groove position, and the part of utmost point ear can weld in utmost point ear welding groove position, and the gummed paper can cover utmost point ear welding groove and cover the part that utmost point ear is located utmost point ear welding groove.

However, in the prior art, a thickness difference is formed in the empty foil region between the tab and the active coating layer, and the flatness of the gummed paper for covering the tab is poor. Under the condition of poor flatness of the gummed paper, the gummed paper is easy to bear uneven stress in the process of formation, so that the gummed paper bonding effect is poor; in addition, after the cell is injected with the electrolyte, the electrolyte is easily concentrated in the thickness difference area, and the adhesive tape is repeatedly soaked in the electrolyte, so that the adhesive tape bonding effect is deteriorated. After the adhesive effect of the adhesive tape is poor, the protective effect of the adhesive tape is easily affected, and even black spots appear in the negative electrode plate area opposite to the position of the tab for lithium precipitation.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides the battery cell, and the adhesive paper used for covering the tab in the battery cell has higher flatness and better bonding effect.

The invention also provides a manufacturing method of the battery cell.

A cell according to an embodiment of the first aspect of the invention comprises: the first pole piece comprises a first current collector and a first active coating, wherein the first active coating is arranged on the surface of the first current collector, the first current collector comprises a first blank area exposed out of the first active coating, and a first welding groove is defined by the first active coating and the first blank area together; a first tab, a portion of which is received in the first welding groove and welded with the first blank area; the first gummed paper comprises a first covering part and a second covering part which are connected with each other, a first accommodating groove is defined by the second covering part and the first covering part together, the first tab is arranged in the first accommodating groove, the second covering part is adhered to the part of the first blank area exposed out of the first tab, and the first covering part covers the part of the first tab in the first welding groove; the thickness of first cover portion is L1, the thickness of second cover portion is L2, the thickness of first utmost point ear is L3, satisfies: l1+l3=l2.

According to some embodiments of the invention, the first gummed paper comprises: the base material comprises a first base part and a second base part with the same thickness, and the second base part is arranged on the periphery of the first base part; the adhesive layer is arranged on one side, close to the first tab, of the base material, and comprises a first adhesive part and a second adhesive part, the second adhesive part is arranged on the periphery of the first adhesive part, the thickness of the second adhesive part is larger than that of the first adhesive part, and the first adhesive part and the second adhesive part jointly define the first accommodating groove; the second base portion and the second bonding portion are laminated to form the second covering portion, and the first base portion and the first bonding portion are laminated to form the first covering portion.

According to some embodiments of the invention, the substrate comprises one or more of thermoplastic polyester, polyethylene, polypropylene, polyvinyl chloride; the adhesive layer comprises one or more of acrylic resin, polycarbonate, polyurethane and rubber.

According to some embodiments of the invention, the first cover has a width of 6-8mm,10 μm.ltoreq.L1.ltoreq.20μm; the width of the second covering part is 2-6mm, and 20 μm < L2 is less than or equal to 80 μm.

According to some embodiments of the invention, further comprising: the second pole piece comprises a second current collector and a second active coating, the second active coating is arranged on the surface of the second current collector, the second current collector comprises a second blank area exposed out of the second active coating, and a second welding groove is defined by the second active coating and the second blank area together; a second tab, a portion of which is received in the second welding groove and welded with the second blank area; the second gummed paper comprises a third covering part and a fourth covering part which are connected with each other, the fourth covering part and the third covering part jointly define a second accommodating groove, the second lug is arranged in the second accommodating groove, the fourth covering part is adhered to the part of the second blank area exposed out of the second lug, and the third covering part covers the part of the second lug positioned in the second welding groove; the thickness of the third covering part is L4, the thickness of the fourth covering part is L5, the thickness of the second lug is L6, and the requirements are satisfied: l4+l6=l5; the isolation film, first pole piece isolation film with the second pole piece stacks gradually and sets up.

According to some embodiments of the invention, the separator further comprises a third gummed paper, wherein the third gummed paper is attached to one side of the second pole piece, which is close to the first pole piece, and the first gummed paper and the third gummed paper are oppositely arranged and separated by the separator.

According to some embodiments of the invention, the separator further comprises a fourth gummed paper, wherein the fourth gummed paper is attached to one side of the first pole piece, which is close to the second pole piece, and the fourth gummed paper and the second gummed paper are oppositely arranged and separated by the separator.

According to a second aspect of the present invention, a method for manufacturing a battery cell includes the steps of: attaching a first gummed paper to a first welding groove of a first pole piece, so that a first pole lug is accommodated in a first accommodating groove of the first gummed paper; the first gummed paper comprises a first covering part and a second covering part, the second covering part is positioned on the periphery of the first covering part, the second covering part and the first covering part jointly define a first accommodating groove, the thickness of the first covering part is L1, the thickness of the second covering part is L2, the thickness of the first tab is L3, and the requirements are met: l1+l3=l2.

According to some embodiments of the invention, the method further comprises the steps of: attaching a second gummed paper to a second welding groove of the second pole piece, so that a second lug is accommodated in a second accommodating groove of the second gummed paper; the second gummed paper comprises a third covering part and a fourth covering part, the fourth covering part is positioned on the periphery of the third covering part, the fourth covering part and the third covering part jointly define a second containing groove, the thickness of the third covering part is L4, the thickness of the fourth covering part is L5, the thickness of the second lug is L6, and the following conditions are satisfied: l4+l6=l5; and after the first gummed paper and the second gummed paper are all pasted, sequentially laminating the first pole piece, the isolating film and the second pole piece.

According to some embodiments of the present invention, before the first pole piece, the isolating film and the second pole piece are stacked, a third gummed paper is attached to the second pole piece, and a fourth gummed paper is attached to the first pole piece; the third gummed paper is arranged opposite to the first gummed paper, and the fourth gummed paper is arranged opposite to the second gummed paper.

The battery cell provided by the invention has at least the following technical effects: the battery cell is used for protecting the outer peripheral part of the adhesive tape of the tab on the blank area and the middle part of the adhesive tape on the tab is thinner. Because the thickness of the part of the adhesive paper attached to the tab and the thickness of the tab are equal to the thickness of the adhesive paper attached to the blank area, after the adhesive paper is attached, one side of the adhesive paper back to the tab is flat, and the flatness of the adhesive paper is high. Because the gummed paper is smooth, the stress uniformity is good in the formation process, the electrolyte is not easy to enrich near the tab, and the gummed paper has good bonding effect, so that the protective effect of the gummed paper on the tab is guaranteed, and the risk of lithium precipitation of the battery cell is reduced.

The manufacturing method of the battery cell has at least the following technical effects: can utilize gummed paper to protect the utmost point ear, and the guard action is stronger, can improve the roughness after the electricity core formation simultaneously.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The invention is further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic view of a first pole piece according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a first pole piece, a first tab and a first adhesive tape after being connected to each other according to an embodiment of the present invention;

FIG. 3 is a cross-sectional view of the structure shown in FIG. 2 taken along section A-A;

FIG. 4 is a schematic view of the first gummed paper of FIG. 3;

FIG. 5 is a schematic diagram of a battery cell (coiled battery cell) according to an embodiment of the present invention;

fig. 6 is a schematic diagram of a partial structure of a battery cell at a first pole piece according to an embodiment of the present invention;

fig. 7 is a schematic diagram of a partial structure of a battery cell at a second pole piece according to an embodiment of the invention.

Reference numerals:

101-a first pole piece, 102-a first current collector, 103-a first active coating, 104-a first blank area, 105-a first welding groove and 106-a first blank groove;

201-first gummed paper, 202-first tab;

301-a substrate, 302-an adhesive layer;

401-first base, 402-second base, 403-first bond, 404-second bond, 405-first receiving slot, 406-first cover, 407-second cover;

501-an electric core, 502-a second pole piece, 503-an isolating film and 504-a second pole lug;

601-second current collector, 602-second active coating, 603-third gummed paper, 604-fifth gummed paper, 605-seventh gummed paper;

701-second gummed paper, 702-third cover part, 703-fourth cover part, 704-second blank area, 706-eighth gummed paper, 707-sixth gummed paper, 708-second accommodation groove, 709-second blank groove, 710-fourth gummed paper, 711-second welding groove.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.

In the description of the present invention, it should be understood that references to orientation descriptions such as upper, lower, front, rear, left, right, etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience of description of the present invention and to simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.

In the description of the present invention, the meaning of a number is one or more, the meaning of a number is two or more, and greater than, less than, exceeding, etc. are understood to exclude the present number, and the meaning of a number is understood to include the present number. The description of the first and second is for the purpose of distinguishing between technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present invention, unless explicitly defined otherwise, terms such as arrangement, installation, connection, etc. should be construed broadly and the specific meaning of the terms in the present invention can be reasonably determined by a person skilled in the art in combination with the specific contents of the technical scheme.

Referring to fig. 5, the battery cell 501 includes a first pole piece 101, a second pole piece 502, a first tab 202, a second tab 504, and an isolation film 503. Wherein, the first pole piece 101 and the second pole piece 502 are respectively an anode piece and a cathode piece, if the first pole piece 101 is an anode piece, the second pole piece 502 is a cathode piece; if the first electrode sheet 101 is a negative electrode sheet, the second electrode sheet 502 is a positive electrode sheet. The first tab 202 is connected to the first pole piece 101, and the second tab 504 is connected to the second pole piece 502. Accordingly, if the first tab 202 is a positive tab, the second tab 504 is a negative tab, and if the first tab 202 is a negative tab, the second tab 504 is a positive tab. The first pole piece 101, the second pole piece 502 and the isolation film 503 are stacked, and the isolation film 503 is disposed between the first pole piece 101 and the second pole piece 502, and the isolation film 503 can prevent the first pole piece 101 and the second pole piece 502 from directly contacting and can allow specific ions to pass through.

It should be noted that, in fig. 5, the relative positions of the first pole piece 101, the second pole piece 502, the first pole tab 202, the second pole tab 504 and the isolation film 503 are mainly shown, and due to the limitation of the drawing, the adhesive paper for protecting the pole tab is not specifically shown in fig. 5, and the mutual matching relationship between the adhesive paper, the pole piece and the pole tab is shown in other drawings. In addition, the gummed paper mentioned in the scheme is insulating gummed paper.

Referring again to fig. 3, the battery cell 501 further includes a first adhesive tape 201, where the first adhesive tape 201 has a first receiving groove 405. Specifically, referring to fig. 4, the first gummed paper 201 includes a first cover part 406 and a second cover part 407; in fig. 4, a portion of the first sticker located between the straight line B and the straight line C is a first cover 406, and a portion of the first sticker located on the left side of the straight line B and the right side of the straight line C is a second cover 407. The second cover portion 407 is disposed on the outer periphery of the first cover portion 406, and the thickness of the second cover portion 407 is greater than that of the first cover portion 406, so that the first cover portion 406 and the second cover portion 407 together define the first accommodating groove 405.

Referring to fig. 1, a first pole piece 101 includes a first current collector 102 and a first active coating 103. The first active coating 103 is disposed on the surface of the first current collector 102, and specifically, in the manufacturing process of the first pole piece 101, slurry containing an active material may be coated on the surface of the first current collector 102, and the slurry is dried to form the first active coating 103. Referring to fig. 1, the first current collector 102 includes a first empty region 104, and the first empty region 104 is exposed to the first active coating 103, i.e., the first empty region 104 is not covered by the first active coating 103. Referring to fig. 1 and 3, the first space 104 and the first active coating 103 together define a first welding groove 105, a portion of the first tab 202 is disposed in the first welding groove 105, and the first tab 202 is welded with the first space 104.

Referring to fig. 3, there is a gap between the edge of the first tab 202 and the sidewall of the first welding groove 105, and the first tab 202 does not entirely cover the first blank region 104. The second covering portion 407 is adhered to the first blank region 104, and the second covering portion 407 covers a portion of the first blank region 104 exposed to the first tab 202 (i.e., a portion not covered by the first tab 202). The first covering portion 406 covers the portion of the first tab 202 located in the first welding groove 105.

Referring to fig. 4, if the thickness of the first cover 406 is L1, the thickness of the second cover 407 is L2, and the thickness of the first tab 202 is L3, l1+l3=l2. It should be noted that, in fig. 4, L3 is not specifically labeled, and L3 may correspond to the dimension of the first tab 202 in the up-down direction in fig. 3; in addition, since the first tab 202 needs to be accommodated in the first accommodating groove 405, the depth of the first accommodating groove 405 is also L3.

In the prior art, the adhesive paper for protecting the tab is generally uniform in thickness, the peripheral part of the adhesive paper is attached to the active coating, and the middle part of the adhesive paper is attached to the tab. Because the tab is protruding for blank district and active coating, the middle part of gummed paper can be jacked by the tab, and gummed paper tortuous setting, the gummed paper one side of tab can not be even in back. In the formation process of the battery cell, uneven gummed paper is easy to bear uneven stress, and the formed gummed paper is easy to adhere to the active coating. In addition, because the gummed paper is uneven, the electrolyte is easy to be enriched in the welding groove of the tab, and as the gummed paper is repeatedly soaked in the electrolyte, the viscosity of the gummed paper is reduced, and the active coating is easy to be not adhered. The protective effect on the tab is reduced after the adhesive effect of the adhesive tape is deteriorated, and the lithium precipitation effect of the battery cell is prevented from being deteriorated.

In the battery cell 501 of the present application, the peripheral portion of the first adhesive tape 201 attached to the first blank area 104 is thicker, and the middle portion attached to the first tab 202 is thinner. Because l1+l3=l2, when the first adhesive tape 201 is stuck, the side of the adhesive tape facing away from the first tab 202 is relatively flat, and the flatness of the adhesive tape is relatively high. Because the first gummed paper 201 is smooth, the stress uniformity is good in the formation process, the electrolyte is not easy to enrich near the first tab 202, and the bonding effect of the first gummed paper 201 is good, so that the protection effect of the first gummed paper 201 on the first tab 202 is guaranteed, and the risk of lithium precipitation of the battery cell 501 is reduced.

In the above embodiment, the fitting relationship among the first gummed paper 201, the first pole piece 101, and the first tab 202 is described. The second tab 504 in the cell 501 may be protected by conventional adhesive paper, or by adhesive paper with thicker sides and thinner middle.

For example, referring to fig. 7, in one embodiment, the second tab 502 includes a second welding groove 711, a portion of the second tab 504 is received in the second welding groove 711, the second gummed paper 701 has a second receiving groove 708, and the second tab 504 is disposed in the second receiving groove 708. The second electrode tab 502 includes a second void region 704, and the second active coating 602 is disposed on a surface of the second current collector 601, and does not cover the second void region 704, and the second void region 704 and the second active coating 602 together define a second weld groove 711. In fig. 7, the second gummed paper 701 includes a third cover part 702 and two fourth cover parts 703 connected to each other, the thickness of the fourth cover part 703 is greater than that of the third cover part 702, the fourth cover part 703 is disposed on the periphery of the third cover part 702, and the third cover part 702 and the fourth cover part 703 together define a second accommodating groove 708. The third covering portion 702 covers a portion of the second tab 504 located in the second accommodating groove 708, and the fourth covering portion 703 is bonded and covers a portion of the second blank area 704 not covered by the second tab 504. If the thickness of the third cover 702 is L4, the thickness of the fourth cover 703 is L5, and the thickness of the second tab 504 is L6, l4+l6=l5. Although L4, L5, and L6 are not specifically shown in fig. 7, the thicknesses of the third cover 702, the fourth cover 703, and the second tab 701 correspond to the respective dimensions in the up-down direction.

The structure of the first gummed paper 201 is explained again below.

Referring to fig. 4, the first gummed paper 201 includes a base 301 and an adhesive layer 302, the adhesive layer 302 is disposed on one side of the base 301 close to the first tab 202, and the adhesive layer 302 itself has a portion with a smaller thickness and a portion with a larger thickness, thereby forming a first receiving groove 405. Specifically, referring to fig. 4, the substrate 301 includes a first base 401 and a second base 402 having the same thickness, and the second bases 402 are disposed on the outer periphery of the first base 401, respectively. The adhesive layer 302 includes a first adhesive portion 403 and a second adhesive portion 404, and the second adhesive portion 404 is located on the outer periphery of the first adhesive portion 403. The thickness of the second adhesive portion 404 is larger than that of the first adhesive portion 403, the first base portion 401 and the first adhesive portion 403 are stacked to form a first cover portion 406, and the second base portion 402 and the second adhesive portion 404 are stacked to form a second cover portion 407.

In this arrangement, the adhesive layer 302 is thicker at the two sides of the first adhesive tape 201, so that the first adhesive tape 201 and the first blank 104 have better adhesion, and the adhesive layer 302 and the first tab 202 can be firmly adhered together. In this arrangement, the sum of the thicknesses of the first adhesive portion 403 and the first base portion 401 is the thickness of the first cover portion 406 (i.e., L1), and the sum of the thicknesses of the second adhesive portion 404 and the second base portion 402 is the thickness of the second cover portion 407 (i.e., L2).

In order to ensure the protective effect and the adhesiveness of the first gummed paper 201, the material of the substrate 301 may include one or more of thermoplastic polyester, polyethylene, polypropylene, and polyvinyl chloride, and the material of the adhesive layer 302 may include one or more of acrylic resin, polycarbonate, polyurethane, and rubber.

In order to achieve both the compactness and the processing convenience of the battery cell 501, the width of the first covering portion 406 may be 6-8mm (inclusive), the thickness of the first covering portion 406 is 10-20 μm (i.e., 10 μm and L1 and 20 μm), the width of the second covering portion 407 is 2-6mm (inclusive), and the thickness of the second covering portion 407 is greater than 20 μm and not greater than 80 μm (i.e., 20 μm < L1 and 80 μm).

In the case where the second adhesive sheet 701 has the second receiving groove 708, the second adhesive sheet 701 may also include the base 301 and the adhesive layer 302, and the structural arrangement and material selection of the second adhesive sheet 701 are the same as those of the first adhesive sheet 201, and a description thereof will not be repeated here. The width selection range and the thickness selection range of the third cover portion 702 may be the same as those of the first cover portion 406, and the width selection range and the thickness selection range of the fourth cover portion 703 may be the same as those of the second cover portion 407.

The design of the cell typically needs to be satisfied; if a certain area of the positive plate is provided with an active material, the area of the negative plate opposite to the area is also required to be provided with the active material; if no active material exists in a certain area of the positive plate, the area of the negative plate opposite to the area should not be provided with active material, or the area of the negative plate coated with active material is covered by insulating gummed paper.

Since there is substantially no active material at the first weld cell 105, accordingly, the cell 501 may include a third glue 603, the third glue 603 being affixed to the second pole piece 502 opposite the first glue 201 (but the third glue 603 and the first glue 201 being separated by a separator film 503). Similarly, the cell 501 may further include a fourth adhesive 710, the fourth adhesive 710 being attached to the first pole piece 101 and disposed opposite the second adhesive 701 (but separated from the fourth adhesive 710 by the separator 503). The third gummed paper 603 and the fourth gummed paper 710 are preferably provided as gummed papers having uniform thickness.

In addition, as shown in fig. 1, the first active coating 103 is disposed on both side surfaces of the first substrate 301, the first active coating 103 is not disposed on both sides of the first space 104, the first welding groove 105 is actually located on one side of the first space 104, and a groove formed on the other side of the first space 104 and not used for accommodating the first tab 202 is referred to as a first space groove 106. Referring again to fig. 6, the cell 501 may include a fifth adhesive 604, and the fifth adhesive 604 may be disposed in the first empty slot 106, reducing the risk of short circuits within the cell 501.

Specifically, referring to fig. 6, if the side of the first space 104 near the first empty slot 106 is exposed, when the position of the separation film 503 corresponding to the first space 104 is pierced or damaged due to high temperature, the lower second pole piece 502 directly contacts the first space 104, thereby causing a short circuit in the battery cell 501. If the fifth adhesive tape 604 is disposed in the first empty slot 106, the fifth adhesive tape 604 (the fifth adhesive tape 604 is insulating) can prevent the first empty area 104 from directly contacting the underlying second pole piece 502 after the position of the separation film 503 corresponding to the first empty area 104 is broken. Therefore, the fifth gummed paper 604 can reduce the risk of short circuit in the battery cell 501, thereby improving the safety of the battery cell 501.

Similarly, referring to fig. 7, in order to improve the safety of the battery cell 501, the battery cell 501 may further include a sixth adhesive tape 707, and the sixth adhesive tape 707 may be disposed in the second blank slot 709. Specifically, the second active coating 602 is not disposed on both sides of the second blank 704, the second welding groove 711 is disposed on one side of the second blank 704, the second blank 709 is disposed on the other side of the second blank 704, and the sixth gummed paper 707 is accommodated in the second blank 709. The fifth gummed paper 604 and the sixth gummed paper 707 can be set as gummed papers having a uniform thickness.

Referring to fig. 6, in the case that the fifth adhesive tape 604 is provided, the battery cell further includes a seventh adhesive tape 605, and the seventh adhesive tape 605 is attached to the second pole piece and is disposed opposite to the fifth adhesive tape 604. Referring to fig. 7, in the case where the sixth adhesive 707 is provided, the battery cell further includes an eighth adhesive 706, and the eighth adhesive 706 is attached to the first electrode sheet and disposed opposite to the sixth adhesive 707.

The method of manufacturing the cell 501 is described again below.

Before assembling the components of the battery cell 501 together, the first pole piece 101, the second pole piece 502, the first adhesive tape 201, the second adhesive tape 701, the first tab 202 and the second tab 504 need to be processed respectively. How to machine the first pole piece 101 with the first welding slot 105 and how to machine the second pole piece 502 with the second welding slot 711 are described above and not repeated here. The tabs are provided as metal strips, the first tab 202 may be cut out of a corresponding metal foil, and the second tab 504 may be similarly manufactured. The first gummed paper 201 can be obtained by coating an adhesive on the substrate 301, wherein the adhesive is solidified or dried to form the adhesive layer 302.

After the above-described respective parts are finished, the first tab 202 is welded into the first welding groove 105, and then the first gummed paper 201 is stuck into the first welding groove 105. And, welding the second tab 504 into the second welding groove 711, and then adhering the second gummed paper 701 into the second welding groove 711. In addition, if the cell 501 includes other glue, all the glue needs to be applied before stacking the pole pieces and the separator 503.

After all the gummed papers are adhered, the first pole piece 101, the separator 503 and the second pole piece 502 are stacked one on another in this order. If the fabricated battery cell 501 is a wound battery cell as shown in fig. 5, it is necessary to wind the first pole piece 101, the separator 503 and the second pole piece 502 after they are stacked on each other; if the fabricated battery cell 501 is a laminated battery cell, the first pole piece 101, the separator 503 and the second pole piece 502 do not need to be wound together after stacking.

In the description of the present invention, the descriptions of the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Claims

1. The electric core, its characterized in that includes:

the first pole piece comprises a first current collector and a first active coating, wherein the first active coating is arranged on the surface of the first current collector, the first current collector comprises a first blank area exposed out of the first active coating, and a first welding groove is defined by the first active coating and the first blank area together;

a first tab, a portion of which is received in the first welding groove and welded with the first blank area;

the first gummed paper comprises a first covering part and a second covering part which are connected with each other, a first accommodating groove is defined by the second covering part and the first covering part together, the first tab is arranged in the first accommodating groove, the second covering part is adhered to the part of the first blank area exposed out of the first tab, and the first covering part covers the part of the first tab in the first welding groove;

the thickness of first cover portion is L1, the thickness of second cover portion is L2, the thickness of first utmost point ear is L3, satisfies: l1+l3=l2;

the first gummed paper comprises a base material and an adhesive layer, wherein the base material comprises a first base part and a second base part which are the same in thickness, and the second base part is arranged on the periphery of the first base part; the adhesive layer is arranged on one side of the base material, which is close to the first tab, and comprises a first adhesive part and a second adhesive part, the second adhesive part is arranged on the periphery of the first adhesive part, the thickness of the second adhesive part is larger than that of the first adhesive part, and the first adhesive part and the second adhesive part jointly define the first accommodating groove; the second base portion and the second bonding portion are laminated to form the second covering portion, and the first base portion and the first bonding portion are laminated to form the first covering portion.

2. The cell of claim 1, wherein the substrate comprises one or more of thermoplastic polyester, polyethylene, polypropylene, polyvinyl chloride; the adhesive layer comprises one or more of acrylic resin, polycarbonate, polyurethane and rubber.

3. The cell of claim 1, wherein the first cover has a width of 6-8mm,10 μm ∈l1 ∈20 μm; the width of the second covering part is 2-6mm, and 20 μm < L2 is less than or equal to 80 μm.

4. The cell of claim 1, further comprising:

the second pole piece comprises a second current collector and a second active coating, the second active coating is arranged on the surface of the second current collector, the second current collector comprises a second blank area exposed out of the second active coating, and a second welding groove is defined by the second active coating and the second blank area together;

a second tab, a portion of which is received in the second welding groove and welded with the second blank area;

the second gummed paper comprises a third covering part and a fourth covering part which are connected with each other, the fourth covering part and the third covering part jointly define a second accommodating groove, the second lug is arranged in the second accommodating groove, the fourth covering part is adhered to the part of the second blank area exposed out of the second lug, and the third covering part covers the part of the second lug positioned in the second welding groove;

the thickness of the third covering part is L4, the thickness of the fourth covering part is L5, the thickness of the second lug is L6, and the requirements are satisfied: l4+l6=l5;

the isolation film, first pole piece isolation film with the second pole piece stacks gradually and sets up.

5. The battery cell of claim 4, further comprising a third adhesive, wherein the third adhesive is attached to a side of the second pole piece, which is close to the first pole piece, and the first adhesive and the third adhesive are disposed opposite to each other and separated by the isolation film.

6. The battery cell of claim 4, further comprising a fourth adhesive, wherein the fourth adhesive is attached to a side of the first pole piece adjacent to the second pole piece, and the fourth adhesive and the second adhesive are disposed opposite to each other and separated by the separator.

7. A method of manufacturing a cell as defined in claim 1, comprising the steps of: attaching a first gummed paper to a first welding groove of a first pole piece, so that a first pole lug is accommodated in a first accommodating groove of the first gummed paper;

the first gummed paper comprises a first covering part and a second covering part, the second covering part is positioned on the periphery of the first covering part, the second covering part and the first covering part jointly define a first accommodating groove, the thickness of the first covering part is L1, the thickness of the second covering part is L2, the thickness of the first tab is L3, and the requirements are met: l1+l3=l2.

8. The method of manufacturing a cell of claim 7, further comprising the steps of:

attaching a second gummed paper to a second welding groove of the second pole piece, so that a second lug is accommodated in a second accommodating groove of the second gummed paper; the second gummed paper comprises a third covering part and a fourth covering part, the fourth covering part is positioned on the periphery of the third covering part, the fourth covering part and the third covering part jointly define a second containing groove, the thickness of the third covering part is L4, the thickness of the fourth covering part is L5, the thickness of the second lug is L6, and the following conditions are satisfied: l4+l6=l5;

and after the first gummed paper and the second gummed paper are all pasted, sequentially laminating the first pole piece, the isolating film and the second pole piece.

9. The method according to claim 8, wherein a third adhesive tape is attached to the second electrode sheet and a fourth adhesive tape is attached to the first electrode sheet before the first electrode sheet, the separator and the second electrode sheet are stacked; the third gummed paper is arranged opposite to the first gummed paper, and the fourth gummed paper is arranged opposite to the second gummed paper.