CN211350883U

CN211350883U - Battery cell, electrochemical device comprising same and electronic device

Info

Publication number: CN211350883U
Application number: CN202020007365.8U
Authority: CN
Inventors: 曾巧; 肖良针; 闫东阳
Original assignee: Ningde Amperex Technology Ltd
Current assignee: Ningde Amperex Technology Ltd
Priority date: 2020-01-03
Filing date: 2020-01-03
Publication date: 2020-08-25
Anticipated expiration: 2030-01-03

Abstract

The embodiment of the application provides a battery cell, which comprises an electrode assembly and packaging bags for accommodating the electrode assembly, wherein an adhesive layer is arranged between the electrode assembly and the packaging bags. When the bonding force and the bonding area ratio of the bonding layer meet a specific relationship, the battery cell can still maintain high safety performance after being impacted. In addition, the embodiment of the application also provides an electrochemical device and an electronic device comprising the battery cell.

Description

Battery cell, electrochemical device comprising same and electronic device

Technical Field

The application relates to the field of energy storage, in particular to a battery cell, an electrochemical device comprising the battery cell and an electronic device comprising the battery cell.

Background

As electrochemical devices (e.g., lithium ion batteries) are widely used in electronic equipment such as cameras, digital video cameras, mobile phones, and notebook computers, manufacturers and users are concerned about safety and reliability. However, the electrochemical device is vulnerable to external impacts (e.g., dropping from a high place) during use, and is susceptible to damage when subjected to external impacts, thereby causing safety problems such as liquid leakage, fire, and even explosion.

In view of this, there is a real need to provide an improved cell with good safety properties.

SUMMERY OF THE UTILITY MODEL

An electrochemical device generally includes a battery cell and a casing for accommodating the battery cell, the battery cell includes an electrode assembly and a packaging bag for accommodating the electrode assembly, and the electrode assembly is formed by sequentially winding or stacking a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate. The electrode assembly may include tabs, and an adhesive layer is disposed between the electrode assembly and the packaging bag. The arrangement of the bonding layer plays an important role in the stability and safety of the battery core after being impacted. If the adhesive layer is improperly arranged, after the battery core is impacted, the electrode assembly is easily separated from the packaging bag, so that the position of the electrode assembly is changed, and potential safety hazards such as liquid leakage, smoking, fire, even explosion and the like can be generated.

The present application addresses at least one of the technical problems set forth in the background section by a particular adhesive layer arrangement.

In one aspect, an embodiment of the present application provides an electric core, including an electrode assembly and a packaging bag accommodating the electrode assembly, an adhesive layer is disposed between the electrode assembly and the packaging bag, and an adhesive force F (unit is N/m) and an adhesive area rate a of the adhesive layer satisfy the following relation:

(calculated as the numerical value of each parameter), wherein the bonding area ratio a is (W1 × L1)/(W2 × L2), wherein W1 is the width of the bonding layer, L1 is the length of the bonding layer, W2 is the width of the electrode assembly (the electrode assembly may be formed by winding or stacking), and L2 is the length of the electrode assembly (or the width of the electrode assembly after the outermost turn is unwound, the outermost turn may be a positive electrode tab, a negative electrode tab, or a separator), W1, L1, W2, and L2 have the same single sheetBits, such as mm or cm, etc.

In some embodiments, the adhesive force F and the adhesive area ratio a of the adhesive layer satisfy the following relation:

when the bonding force and the bonding area rate of the bonding layer in the battery cell accord with the relational expression, after the battery cell is impacted, proper friction force exists between the electrode assembly and the packaging bag, so that the electrode assembly and the packaging bag cannot be separated or excessively torn.

In some embodiments, bonded to the pouch is a positive electrode tab in an electrode assembly. In some embodiments, bonded to the pouch is a negative electrode tab in an electrode assembly. In some embodiments, bonded to the package is a separator in the electrode assembly.

According to an embodiment of the present application, the bonding area ratio a is not less than 20% and not more than 97%. In some embodiments, the bonding area ratio a is not less than 70% and not more than 97%. When the bonding area ratio a of the bonding layer is within the above range, the electrode assembly is easily packaged in a packaging bag, and the surface of the bonding layer is flat, so that the interface of the battery cell is not affected, and the cycle performance of the battery cell is not affected.

According to the embodiment of the application, the bonding force F is not less than 1N/m and not more than 150N/m. In some embodiments, the adhesion force F is not less than 10N/m and not more than 120N/m. In some embodiments, the adhesion force F is not less than 30N/m and not more than 100N/m. In some embodiments, the adhesion force F is not less than 50N/m and not more than 80N/m.

According to an embodiment of the present application, the electrode assembly includes a first pole piece including a first current collector, a first active material layer disposed on at least a portion of the first current collector, and a first tab electrically connected to a starting end of the first current collector, the starting end of the first current collector not being provided with the first active material layer; or the first active material layer is provided with a first groove, and the first tab is arranged in the first groove and electrically connected with the first current collector.

According to an embodiment of the present application, the first pole piece may further include at least one first tab, the first active material layer is provided with at least one first groove, and the plurality of first tabs are respectively disposed in the corresponding at least one first groove and electrically connected to the first current collector; or the at least one first tab is cut through the first current collector.

According to an embodiment of the application, the electrode assembly comprises a second pole piece having substantially the same arrangement as the first pole piece. In some embodiments, the second pole piece comprises a second current collector, a second active material layer disposed on at least a portion of the second current collector, and a second pole tab electrically connected to the starting end of the second current collector, wherein the starting end of the second current collector is not disposed with the second active material layer; or the second active material layer is provided with a second groove, and the second electrode lug is arranged in the second groove and electrically connected with the second current collector. In some embodiments, the second pole piece comprises at least one second pole tab, the first active material layer is provided with at least one second groove, and the plurality of second pole tabs are respectively arranged in the corresponding at least one second groove and electrically connected with the second current collector; or the at least one second pole ear is cut from the second current collector.

According to an embodiment of the present application, the adhesive layer is a single layer structure or a multi-layer structure.

According to an embodiment of the application, the adhesive layer is in the shape of a sheet, a dot or a strip.

According to an embodiment of the present application, the adhesive layer is continuously or discontinuously disposed between the electrode assembly and the packaging bag.

According to an embodiment of the present application, the adhesive layer is disposed on at least one straight section of the electrode assembly after winding.

According to an embodiment of the application, the bonding layer has a regular topography, an irregular topography, or a combination thereof.

According to an embodiment of the present application, the adhesive layer includes petroleum resin and at least one of polybutadiene, polypropylene, polypentadiene, and styrene or butadiene copolymer. In some embodiments, the bonding layer further comprises at least one of wood flour, talc, or calcium carbonate.

In another aspect, embodiments of the present application provide an electrochemical device including any one of the cells described above according to embodiments of the present application.

In yet another aspect, embodiments provide an electronic device comprising any of the electrochemical devices described above according to embodiments of the present application.

Additional aspects and advantages of embodiments of the present application 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 embodiments of the present application.

Drawings

Drawings necessary for describing embodiments of the present application or the prior art will be briefly described below in order to describe the embodiments of the present application. It is to be understood that the drawings in the following description are only some of the embodiments of the present application. It will be apparent to those skilled in the art that other embodiments of the drawings can be obtained from the structures illustrated in these drawings without the need for inventive work.

Fig. 1 shows a schematic diagram of an outermost ring of a pole piece of an electrode assembly according to an embodiment of the present application after deployment.

Fig. 2A illustrates a schematic view of an electrode assembly having one sheet-like regional adhesive layer according to an embodiment of the present application.

Fig. 2B shows a schematic view of an electrode assembly having a plurality of sheet-like regional adhesive layers according to an embodiment of the present application.

Fig. 2C shows a schematic view of an electrode assembly having a dot region adhesive layer according to an embodiment of the present application.

Fig. 2D shows a schematic view of an electrode assembly having one stripe region adhesive layer according to an embodiment of the present application.

Fig. 2E shows a schematic view of an electrode assembly having a plurality of stripe region adhesive layers according to an embodiment of the present application.

Fig. 3 shows a schematic diagram of a first pole piece according to an embodiment of the present application.

Fig. 4 illustrates a cross-sectional view of an electrode assembly including the first pole piece shown in fig. 3.

Fig. 5 shows a schematic view of a first pole piece according to another embodiment of the present application.

Fig. 6 illustrates a cross-sectional view of an electrode assembly including the first pole piece shown in fig. 5.

Fig. 7 shows a schematic view of a first pole piece according to yet another embodiment of the present application.

Fig. 8 illustrates a cross-sectional view of an electrode assembly including the first pole piece shown in fig. 7.

Detailed Description

Embodiments of the present application will be described in detail below. Throughout the specification, the same or similar components and components having the same or similar functions are denoted by like reference numerals. The embodiments described herein with respect to the figures are illustrative in nature, are diagrammatic in nature, and are used to provide a basic understanding of the present application. The embodiments of the present application should not be construed as limiting the present application.

In this application, unless specified or limited otherwise, when a first feature is located "on" or "under" a second feature in a structure, the structure may comprise an embodiment in which the first feature is in direct contact with the second feature, and may comprise another embodiment in which the first feature is not in direct contact with the second feature, but is in contact with an additional feature formed therebetween. Furthermore, when a first feature is located "on," over "or" on top of "a second feature, it can include embodiments in which the first feature is located" on, "over" or "on top" the second feature, directly or obliquely, or merely represents that the height of the first feature is higher than that of the second feature; when a first feature is located "under," under "or" at the bottom of "a second feature, embodiments may be included in which the first feature is located" under, "under" or "at the bottom of" the second feature, either directly or obliquely, or simply represents that the height of the first feature is lower than the height of the second feature.

The embodiment of the application provides an electric core, include electrode subassembly and accept the wrapping bag of electrode subassembly with be provided with the adhesive linkage between the wrapping bag, the adhesion F and the bonding area rate an of adhesive linkage satisfy following relational expression:

the bonding area ratio a is (W1 × L1)/(W2 × L2), where W1 is the width of the bonding layer, L1 is the length of the bonding layer, and W2 is the width of the electrode assembly, where the electrode assembly may be formed by sequentially winding or stacking a positive electrode tab, a separator, and a negative electrode tab, and L2 is the length of the electrode assembly, or L2 is the width of the electrode assembly after the outermost turn of the electrode assembly is unwound, and the outermost turn may be a positive electrode tab (as shown in fig. 1), a negative electrode tab, or a separator.

In some embodiments, the adhesive layer is in the form of a sheet, dot, or stripe.

When the adhesive layers are sheet-shaped, the adhesive area ratio of the adhesive layers is the ratio of the sum of the adhesive areas of the sheet-shaped adhesive layers (i.e., the areas of the adhesive layers in contact with the electrode assembly) to the surface area of the electrode assembly on the side where the adhesive layers are disposed. As shown in fig. 2A, when the adhesive layer has one sheet-like adhesive layer, a ═ (W1 × L1)/(W2 × L2). As shown in fig. 2B, when the adhesive layer includes a plurality of sheet-shaped adhesive layers (a, B, c, d, and e), the adhesive area is the sum of the areas of the sheet-shaped adhesive layers a, B, c, d, and e, and a ═ (W1a × L1a + W1B × L1B + W1c × L1c + W1d × L1d + W1e × L1e)/(W2 × L2).

When the adhesive layer is in the form of dots, the adhesive area ratio is the ratio between the area surrounded by the outermost adhesive dots and the surface area of the electrode assembly on the side where the adhesive layer is disposed. As shown in fig. 2C, the adhesive layer includes a plurality of dot-shaped adhesive layers, and a is (W1 × L1)/(W2 × L2).

When the adhesive layers are in the form of strips, the adhesive area ratio is the ratio of the sum of the areas of the strip-shaped adhesive layers to the surface area of the electrode assembly on the side where the adhesive layers are provided. As shown in fig. 2D, when the adhesive layer has one stripe-shaped adhesive layer, a is (W1 × L1)/(W2 × L2). As shown in fig. 2E, when the adhesive layer includes a plurality of stripe-shaped adhesive layers (x and y), the adhesive area is the sum of the stripe-shaped adhesive layers x and y, and a ═ is (W1x × L1x + W1y × L1y)/(W2 × L2).

In some embodiments, the adhesive layer is a single layer structure or a multi-layer structure.

In some embodiments, the adhesive layer is continuously disposed between the cell and the casing, as shown in fig. 2A and 2D.

In some embodiments, the adhesive layer is discontinuously disposed between the electrode assembly and the pouch, as shown in fig. 2B, 2C, and 2E.

In some embodiments, the bonding layer has a regular topography (as shown in fig. 2E), an irregular topography (as shown in fig. 2D), or a combination thereof. The term "regular topography" is a regular topography of the adhesive layer boundary, e.g., square, rectangular, diamond, circular, oval, triangular, trapezoidal, polygonal, etc. The term "irregular topography" refers to a topography of the bond layer boundary that is irregular, i.e., a topography other than a regular topography, e.g., those that cannot be named in conventional shape terms.

In some embodiments, the bonding area ratio a of the bonding layer is not less than 20% and not more than 97%. In some embodiments, the bonding area ratio a is not less than 70% and not more than 97%. When the bonding area ratio of the bonding layer is within the above range, the electrode assembly is easily packaged in a packaging bag, and the surface of the bonding layer is flat, so that the interface of the battery cell is not affected, and the cycle performance of the battery cell is not affected.

In some embodiments, the adhesion force F is not less than 1N/m and not greater than 150N/m. In some embodiments, the adhesion force F is not less than 10N/m and not more than 120N/m. In some embodiments, the adhesion force F is not less than 30N/m and not more than 100N/m. In some embodiments, the adhesion force F is not less than 50N/m and not more than 80N/m.

In some embodiments, the cell includes a first pole piece including a first current collector, a first active material layer disposed on at least a portion of the first current collector, and a first tab, as may be shown in fig. 3 and 4.

In some embodiments, the first active material layer is not disposed at the starting end of the first current collector, and the first tab is electrically connected to the starting end of the first current collector, as shown in fig. 3 and 4.

Fig. 3 illustrates a first pole piece according to an embodiment of the present application. First pole piece 300 includes a first current collector 301, a first active material 302, and a first tab 303. The first active material 302 is disposed on both surfaces (i.e., the first surface 300a and the second surface 300b) of the first current collector 301. The first current collector 301 includes a starting end 304,

intermediate portions

305a, 305b, and trailing

ends

306a, 306b in the winding direction, the first active material 302 is disposed in the

intermediate portions

305a, 305b of the first current collector 301, and the first tab 303 is disposed at the starting end 304 of the first current collector 301 and electrically connected to the first current collector 301. As shown in fig. 3, the middle portion 305a on which the first active material 302 is disposed on the first surface 300a is longer than the middle portion 305b on which the first active material 302 is disposed on the second surface 300b, so that the first current collector 301 includes a single-sided portion 307, i.e., a portion having the first active material 302 only on a single-sided surface of the first current collector 301. In some embodiments, second pole piece 310 includes a second current collector 311, a second active material 312, and second pole ears 313, and second pole piece 310 may be in substantially the same arrangement as first pole piece 300. Fig. 4 shows an electrode assembly formed by sequentially winding the first pole piece 300, the separator 320 and the second pole piece 310 shown in fig. 3, wherein W2 is the width of the electrode assembly after winding.

In some embodiments, the first active material layer is provided with a first groove, and the first tab is disposed in the first groove and electrically connected to the first current collector, as shown in fig. 5 and 6.

Fig. 5 illustrates a first pole piece according to another embodiment of the present application. First pole piece 500 includes a first current collector 501, a first active material 502, and a first tab 503. The first active material 502 is disposed on both surfaces (i.e., the first surface 500a and the second surface 500b) of the first current collector 501. The first current collector 501 includes a starting end 504,

intermediate portions

505a, 505b, and trailing

ends

506a, 506b in the winding direction, and the first active material 502 is disposed in the

intermediate portions

505a, 505b of the first current collector 501. The

intermediate portions

505a, 505b of the first current collector 501 where the first active material 502 is disposed are provided with grooves 508, and the first tab 503 is disposed in the grooves 508 and electrically connected to the first current collector 501. As shown in fig. 5, the middle portion 505a on which the first active material 502 is disposed on the first surface 500a is longer than the middle portion 505b on which the first active material 502 is disposed on the second surface 500b, so that the first current collector 501 includes a single-sided portion 507, i.e., a portion having the first active material 502 only on a single-sided surface of the first current collector 501. In some embodiments, the second pole piece 510 includes a second current collector 511, a second active material 512, and second pole ears 513, and the second pole piece 510 may be in substantially the same arrangement as the first pole piece 500. Fig. 6 shows an electrode assembly formed by winding the first pole piece 500, the separator 520 and the second pole piece 510 shown in fig. 5, wherein W2 is the width of the electrode assembly after winding.

In some embodiments, the first pole piece includes at least one first tab, the first active material layer is provided with at least one first groove, and the plurality of first tabs are respectively disposed in the corresponding at least one first groove and electrically connected to the first current collector, as shown in fig. 7 and 8.

In some embodiments, the at least one first tab is cut through the first current collector.

Fig. 7 illustrates a first pole piece according to yet another embodiment of the present application. The first pole piece 700 includes a first current collector 701, a first active material 702, and a first tab 703. First active material 702 is disposed on both surfaces (i.e., first surface 700a and second surface 700b) of first current collector 701. The first current collector 701 includes

coated regions

705a, 705b and

uncoated regions

706a, 706b in the winding direction, and the first active material 702 is disposed in the

coated regions

705a, 705b of the first current collector 701. A first tab 703 is cut through the first current collector 701. As shown in fig. 7, the middle portion 705a on which the first active material 702 is disposed on the first surface 700b is longer than the middle portion 705b on which the first active material 702 is disposed on the second surface 700b, so that the first current collector 701 includes a single-sided portion 707, i.e., a portion having the first active material 702 only on a single-sided surface of the first current collector 701. In some embodiments, the second pole piece 710 includes a second current collector 711, a second active material 712, and second pole ears 713, and the second pole piece 710 may be in substantially the same arrangement as the first pole piece 700. Fig. 8 shows an electrode assembly formed by winding the first pole piece 700, the separator 720 and the second pole piece 710 shown in fig. 7, wherein W2 is the width of the electrode assembly after winding.

In some embodiments, the adhesive layer is disposed on at least one straight section of the electrode assembly after winding.

In some embodiments, the bonding layer comprises petroleum resin and at least one of polybutadiene, polypropylene, polypentadiene, and styrene or butadiene copolymer. In some embodiments, the bonding layer further comprises at least one of wood flour, talc, or calcium carbonate.

Embodiments of the present application also provide an electrochemical device comprising a cell according to any of the embodiments of the present application. The electrochemical device of the embodiment of the present application includes any device in which an electrochemical reaction occurs, and specific examples thereof include all kinds of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In particular, the electrochemical device is a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery.

Embodiments of the present application further provide an electronic device comprising an electrochemical device according to any of the embodiments of the present application. The electrochemical device of the present application includes any device in which electrochemical reactions occur, and specific examples thereof include all kinds of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In particular, the electrochemical device is a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery. In some embodiments, an electrochemical device of embodiments of the present application includes a positive electrode sheet having a positive active material capable of intercalating and deintercalating metal ions, a negative electrode sheet according to embodiments of the present application, an electrolyte, and a separator disposed between the positive electrode sheet and the negative electrode sheet.

While the preparation of flexible packages is described below with reference to lithium ion batteries as an example and in conjunction with specific examples, those skilled in the art will appreciate that the preparation methods described herein are merely examples and that any other suitable preparation method is within the scope of the present application.

Examples

Firstly, preparation of battery cell

And sequentially placing the positive pole piece, the isolating membrane and the negative pole piece, and winding to form the electrode assembly. An adhesive substance is disposed on a straight section of the outer surface of the wound electrode assembly to form an adhesive layer. And placing the electrode assembly in a packaging bag, and bonding the bonding layer with the packaging bag to obtain the battery cell.

Second, testing method

1. Bonding area rate testing method

The width and length of the adhesive layer, and the width and length of the electrode assembly were measured, and the adhesive area ratio a was calculated by the following formula:

a＝(W1×L1)/(W2×L2)

wherein W1 is a width of the adhesive layer, L1 is a length of the adhesive layer, W2 is a width of the electrode assembly, and L2 is a length of the electrode assembly.

2. Adhesion testing method

And (4) disassembling the battery cell discharged to 2.8V, and keeping the bonding interface between the packaging bag and the electrode assembly good. And (4) placing the disassembled battery cell into a punching machine, punching and preparing into small strips with the thickness of 4-8 mm. And pasting a double-faced adhesive tape on the steel plate, and adhering the electrode assembly surface of the small test strip on the double-faced adhesive tape for fixing. And fixing one end of the packaging bag with a hard paper sheet with the same width to obtain a sample to be tested.

One end of the steel plate is fixed at the lower end of an universal tensile machine (manufacturer: Yuyao, Xuyan New energy Co., Ltd.), and the paper strip is reversely pulled for 180 degrees and is fixed at the upper end of the tensile machine to be tested at the speed of 50 mm/min. The average of the plateau of the tensile curve is recorded after the test is completed. Each set tested 30 samples in parallel.

3. Drop safety testing method

At least 30 cell samples are taken and allowed to fall freely from a height (e.g., 1.5 meters). If the cell sample does not smoke, fire and leak, the record is passed. The sample rate of passing the drop safety test was recorded.

4. Method for testing retention rate of circulating capacity

And (2) at 45 ℃, carrying out constant current charging on the battery cell to 4.4V by using a current of 0.8C, carrying out constant voltage charging on the battery cell to 0.2C by using a voltage of 4.4V, standing for 5min, carrying out constant current discharging on the battery cell to 3.0V by using a current of 1C, standing for 5min, recording the first discharge capacity, circulating for 500 times (namely repeatedly executing the steps for 500 times) in the same way, and measuring the discharge capacity after 500 times of circulation. The cycle capacity retention of the cell was calculated by the following formula:

the cycle capacity retention rate is the discharge capacity after the 500 th cycle/the discharge capacity of the first cycle × 100%.

Third, test results

Table 1 shows the bonding area ratio and the bonding force of the adhesive layer and the drop safety and cycle performance of the battery cell in each comparative example and example.

Table 1 test results for each comparative example and example

The results show that the ratio of the bonding area a and the bonding force F of the adhesive layer do not satisfy

And in time, the falling safety of the battery core is poor. When the bonding area ratio a and the bonding force F of the bonding layer satisfy

And the falling safety of the battery cell is obviously improved. Further, the ratio of the bonding area a to the bonding force F in the adhesive layer satisfies

When the bonding area ratio a is in the range of 20% to 97%, the cycle capacity retention ratio of the cell is not adversely affected.

Reference throughout this specification to "an embodiment," "some embodiments," "one embodiment," "another example," "an example," "a specific example," or "some examples" means that at least one embodiment or example in this application includes a particular feature, structure, material, or characteristic described in the embodiment or example. Thus, throughout the specification, descriptions appear, for example: "in some embodiments," "in an embodiment," "in one embodiment," "in another example," "in one example," "in a particular example," or "by example," which do not necessarily refer to the same embodiment or example in this application. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

Although illustrative embodiments have been illustrated and described, it will be appreciated by those skilled in the art that the above embodiments are not to be construed as limiting the application and that changes, substitutions and alterations can be made to the embodiments without departing from the spirit, principles and scope of the application.

Claims

1. The utility model provides an electric core, includes electrode assembly and accepts the wrapping bag of electrode assembly, its characterized in that electrode assembly with be provided with the adhesive linkage between the wrapping bag, the adhesion F and the bonding area rate a of adhesive linkage satisfy following relational expression:

wherein the bonding area ratio a is (W1 × L1)/(W2 × L2), wherein W1 is the width of the bonding layer, L1 is the length of the bonding layer, W2 is the width of the electrode assembly, and L2 is the length of the electrode assembly, and W1, L1, W2, and L2 have the same unit.

2. The cell of claim 1, wherein the bond area fraction a is not less than 20% and not greater than 97%.

3. The cell of claim 1, wherein the adhesion force F is not less than 1N/m and not greater than 150N/m.

4. The cell of claim 1, wherein the electrode assembly comprises a first pole piece comprising a first current collector, a first active material layer disposed on at least a portion of the first current collector, and a first tab having no first active material layer disposed at a starting end of the first current collector, and wherein the first tab is electrically connected to the starting end of the first current collector; or the first active material layer is provided with a first groove, and the first tab is disposed in the first groove and electrically connected to the first current collector.

5. The cell of claim 1, wherein the electrode assembly comprises a first pole piece comprising a first current collector, a first active material layer disposed on at least a portion of the first current collector, the first active material layer being provided with at least one first groove, and at least one first tab disposed within a respective one of the at least one first groove and electrically connecting the first current collector; or the at least one first tab is cut by the first current collector.

6. The cell of claim 1, wherein the bonding layer is a single layer structure or a multilayer structure.

7. The cell of claim 1, wherein the adhesive layer is in the form of a sheet, dot, or strip; or the bonding layer has a regular topography, an irregular topography, or a combination thereof.

8. The electrical core of claim 1, wherein the adhesive layer is disposed continuously or discontinuously between the electrode assembly and the packaging bag.

9. An electrochemical device comprising a cell according to any of claims 1 to 8.

10. An electronic device comprising the electrochemical device of claim 9.