CN203800133U - Winding cell and electrochemical device - Google Patents

Abstract

The utility model provides a winding type electric core and an electrochemical device, comprising: a first pole piece with a first current collector; a first tab electrically connected to the first current collector; a second pole piece with a second current collector The dipole piece; the second tab electrically connected to the second current collector; the isolation film. The position where the first tab is disposed on the first current collector and the position where the second tab is disposed on the second current collector is at the beginning of the winding of the wound cell or at the end of the winding of the wound cell. The first tab has a first contact portion in contact with the first current collector and a first lead-out portion that exposes the first current collector, and the second tab has a second contact portion that contacts the second current collector and exposes the second current collector. The second lead-out part, the first contact part and the second contact part are misaligned with each other, so as to ensure that they do not overlap each other in the width direction of the battery core after being wound up to form the battery core.

Description

Wound cells and electrochemical devices

technical field

The utility model relates to the field of energy storage devices, in particular to a winding electric core and an electrochemical device.

Background technique

At present, lithium-ion batteries have become the first choice or even the only power source for consumer portable electronic products. With the rapid development of mobile communication devices and multimedia devices including mobile phones and notebook computers, people have put forward higher and higher requirements for the performance of lithium-ion secondary batteries used in these devices, especially lithium-ion secondary batteries energy density.

As the functions of various mobile devices become more and more complex, the power consumption during use is also getting higher and higher, and at the same time, the size of the devices is getting smaller and smaller, and the space for lithium-ion batteries is getting less and less. This requires lithium-ion batteries to have higher energy density and provide maximum energy in as small a space as possible.

At present, the traditional square lithium-ion battery manufacturing process is to weld the strip-shaped tabs on the battery pole pieces to protrude from the outside of the battery cell, as a channel for current transmission inside and outside the battery. Due to the limited space, the width of the strip tab is narrow, generally 3mm-10mm (depending on the size of the battery), and its width is equivalent to one-tenth to one-fifteenth of the battery width. As a result, the thickness of the position where the tab is welded inside the battery is thicker than the other positions where the tab is not welded, so that the battery cannot be kept flat along the width direction, but is slightly undulating, resulting in uneven force distribution inside the battery. During use, the pole piece will continue to expand and contract with the charging and discharging of the battery, further aggravating the uneven force. Under the action of stress, the battery undergoes more serious wave-shaped deformation, and eventually fails and cannot be used.

Utility model content

In view of the problems existing in the background technology, the purpose of the utility model is to provide a winding battery cell and an electrochemical device, which can effectively suppress the deformation of the battery cell and improve the performance of the battery cell.

In order to achieve the above object, in the first aspect, the utility model provides a winding battery core, which includes: a first pole piece, including a first current collector and a first The first diaphragm of the active material; the first tab, arranged and electrically connected to the first current collector of the first pole piece; the second pole piece, opposite in polarity to the first pole piece, includes a second current collector and is arranged on the The second diaphragm containing the second active material on the surface of the second current collector; the second tab is arranged and electrically connected to the second current collector of the second pole piece; and the isolation film is arranged on the first pole piece and the second pole piece. Between the second pole pieces; wherein, the first pole piece, the separator and the second pole piece are sequentially wound to form a wound battery; at the beginning and end of the winding of the wound battery, The first current collector of the first pole piece is not provided with a first diaphragm, and the second current collector of the second pole piece is not provided with a second diaphragm. Wherein, the position where the first tab is arranged on the first current collector of the first pole piece and the position where the second tab is arranged on the second current collector of the second pole piece is at the beginning of the winding of the wound electric core or At the winding end of the wound cell. The first tab has a first contact portion in contact with the first current collector and a first lead-out portion exposing the first current collector. The length of the first contact portion is 2/3 to 1 of the length of the wound battery core. The width of a contact portion is 1/3˜1/2 of the width of the winding battery core. The second tab has a second contact portion in contact with the second current collector and a second lead-out portion exposing the second current collector. The length of the second contact portion is 2/3 to 1 of the length of the wound battery core. The width of the two contact parts is 1/3-1/2 of the width of the winding battery core. Wherein, the first contact portion of the first tab and the second contact portion of the second tab are misaligned with each other to ensure that the first contact portion of the first tab and the second contact portion of the second tab are wound to form the battery core. The contact parts do not overlap with each other in the width direction of the cell.

In order to achieve the above object, in the second aspect, the utility model provides an electrochemical device, which includes: the winding battery cell according to the first aspect of the utility model; the electrolyte; and a packaging bag for packaging and winding The battery cell contains the electrolyte solution so that the electrolyte solution soaks the first pole piece and the second pole piece of the wound battery cell.

The beneficial effects of the utility model are as follows:

The contact areas of the first tab and the second tab with the first current collector and the second current collector respectively increase, and the sum of the widths of the first contact portion and the second contact portion is close to or equal to the width of the wound cell, Therefore, the thickness distribution of the cell on the plane is more uniform, and the force of the cell is more uniform, thereby suppressing the local deformation of the cell; at the same time, due to the increase in the contact area between the tab and the current collector, the overall increase in the cell Anti-deformation ability, effectively inhibit the deformation of the battery cell; the increase of the contact area can optimize the contact resistance, improve the capacity retention rate of the high-rate discharge of the battery cell, thereby improving the performance of the battery cell.

The first lug and the second lug with increased width do not overlap each other, do not increase the extra thickness of the battery core, and thus do not affect the energy density of the battery core.

Description of drawings

Fig. 1 is a front view of an embodiment of a first pole piece of a wound battery according to the present invention;

Fig. 2 is a front view of another embodiment of the first pole piece of the wound electric core according to the present invention;

Fig. 3 is a schematic plan view of an embodiment of a winding battery core according to the present invention;

Fig. 4 is a front cross-sectional view of a winding battery core according to the present invention;

Fig. 5 is a schematic plan view of an embodiment of a winding battery core according to the present invention;

Fig. 6 is a schematic plan view of a pair of proportions of the winding battery core according to the present invention;

FIG. 7 is a schematic plan view of an existing winding battery cell;

Fig. 8 is a schematic plan view of an existing winding battery cell;

FIG. 9 is a schematic plan view of a conventional wound battery.

Wherein, the reference signs are explained as follows:

1 winding cell 14 second tab

11 first pole piece 141 second contact part

111 The first collector 142 The second outlet

112 First diaphragm 15 Isolation film

12 The first tab S winding starting point

121 The first contact part E winding end

122 first lead-out part L length direction

13 second pole piece W width direction

131 second current collector T thickness direction

132 second diaphragm 2 bags

Detailed ways

The winding battery cell according to the first aspect of the present invention will be described in detail below with reference to the accompanying drawings.

In the description of the following embodiments, L is the length direction of the wound battery 1 and its components, W is the width direction of the wound battery 1 and its components, and T is the wound battery 1 and its components. The thickness direction of each part.

Referring to FIGS. 1 to 5 , according to the first aspect of the present utility model, the winding cell 1 includes: the first pole piece 11 , including the first current collector 111 and the surface of the first current collector 111 containing the first A first diaphragm 112 of active material; the first tab 12 is arranged and electrically connected to the first current collector 111 of the first pole piece 11; the second pole piece 13 is opposite in polarity to the first pole piece 11, including The second current collector 131 and the second diaphragm 132 containing the second active material disposed on the surface of the second current collector 131; the second tab 14 is disposed and electrically connected to the second current collector of the second pole piece 13 131; and the separator 15, which is arranged between the first pole piece 11 and the second pole piece 13; wherein, the first pole piece 11, the separator 15 and the second pole piece 13 are sequentially wound to form a wound electric core 1; At the winding start S and the winding end E of the winding cell 1, the first current collector 111 of the first pole piece 11 is not provided with the first diaphragm 112, and the first diaphragm 112 of the second pole piece 13 is not provided. The second collector 131 is not provided with the second diaphragm 132 .

Wherein, the first tab 12 is arranged at the position of the first current collector 111 of the first pole piece 11 and the second tab 14 is arranged at the position of the second current collector 131 of the second pole piece 13 in the winding cell 1 The starting point S of the winding or the ending point E of the winding cell 1 .

The first tab 12 has a first contact portion 121 in contact with the first current collector 111 and a first lead-out portion 122 exposing the first current collector 111, and the length of the first contact portion 121 is 1/2 of the length of the wound electric core 1. 2/3˜1, the width of the first contact portion 121 is 1/3˜1/2 of the width of the wound battery 1 .

The second tab 14 has a second contact portion 141 in contact with the second current collector 131 and a second lead-out portion 142 exposing the second current collector 131, and the length of the second contact portion 141 is 1/2 of the length of the wound electric core 1. 2/3˜1, the width of the second contact portion 141 is 1/3˜1/2 of the width of the wound battery 1 .

Wherein, the first contact portion 121 of the first tab 12 and the second contact portion 141 of the second tab 14 are misaligned with each other, so as to ensure that the first contact portion 121 of the first tab 12 and the second contact portion 141 of the first tab 12 are formed after winding to form an electric core. The second contact portions 141 of the dipole tabs 14 do not overlap with each other in the cell width direction (see FIG. 4 ).

Referring to Figure 8, the traditional winding cell 1 uses strip-shaped (i.e. rectangular) tabs. The lead-out part of the tab and the contact part have the same width and thickness. The width is generally 2-7mm, and the thickness is generally: 0.03 ~0.15mm. After being assembled into the wound cell 1, the position of the wound cell 1 with tabs is obviously thicker than the position without tabs, and the force is not uniform. The unevenness will be exacerbated by the expansion of the pole piece during the charging and discharging process, which will eventually lead to the deformation of the wound battery 1 in a wavy or "S" shape.

In the wound battery core 1 according to the present invention, the first tab 12 has a first contact portion 121 in contact with the first current collector 111 and a first lead-out portion 122 exposing the first current collector 111 , the second pole The ear 14 has a second contact portion 141 in contact with the second current collector 131 and a second lead-out portion 142 exposing the second current collector 131. The lengths of the first contact portion 121 and the second contact portion 141 are respectively 100% of the length of the wound battery cell. 2/3˜1 of the length of 1, and the widths of the first contact portion 121 and the second contact portion 141 are respectively 1/3˜1/2 of the width of the wound battery 1 . The contact areas of the first tab 12 and the second tab 14 with the first current collector 111 and the second current collector 131 respectively increase, and the sum of the widths of the first contact portion 121 and the second contact portion 141 is close to or equal to the winding width. The width of the type battery 1, so that the thickness distribution of the battery on the plane is more uniform, and the force of the battery is more uniform, thereby reducing the local deformation of the battery; at the same time, due to the increased contact area between the tab and the current collector, the On the whole, the anti-deformation ability of the battery is increased, and the deformation of the battery is effectively suppressed; the increase in the contact area can optimize the contact resistance, improve the capacity retention rate of the high-rate discharge of the battery, and thereby improve the performance of the battery.

The first lug 12 and the second lug 14 with increased width do not overlap each other, do not increase the extra thickness of the battery core, and thus do not affect the energy density of the battery core.

In an embodiment of the wound battery cell according to the present invention, the first pole piece 11 can be a negative pole piece or a positive pole piece, and the second pole piece 13 can be a positive pole piece or a negative pole piece accordingly.

In an embodiment of the wound electric core according to the present invention, the first tab 12 can be welded to the first current collector 111 of the first pole piece 11; the second tab 14 can be welded to the second pole piece 13 The second current collector 131.

In an embodiment of the wound battery core according to the present invention, the material of the first tab 12 and the second tab 14 can be pure aluminum strip, pure copper strip, pure nickel strip, or surface-treated Aluminum strip, copper strip, nickel strip, or copper alloy, nickel alloy, copper-plated, nickel-plated metal strip.

In an embodiment of the wound battery core according to the present invention, the width of the first lead-out portion 122 of the first tab 12 and the second lead-out portion 142 of the second tab 14 may be 3mm-10mm, and the length may be 10mm-18mm.

In an embodiment of the wound battery cell according to the present invention, the thickness of the first tab 12 and the second tab 14 may be 0.05mm-0.15mm.

In an embodiment of the winding battery core according to the present invention, the first contact portion 121 and the first lead-out portion 122 of the first tab 12 can form a T shape (refer to FIG. 2 ) or an L shape (refer to FIG. 1 ); the second contact portion 141 and the second lead-out portion 142 of the second tab 14 may form a T shape (refer to FIG. 4 ) or an L shape. But in practice, it is not limited to these two cases.

In an embodiment of the wound electric core according to the present invention, the width of the first contact portion 121 of the first tab 12 and the width of the second contact portion 141 of the second tab 14 may be the same or different; The length of the first contact portion 121 of a tab 12 and the length of the second contact portion 141 of the second tab 14 may be the same or different.

Next, the electrochemical device according to the second aspect of the present invention will be described.

Referring to Fig. 4, the electrochemical device according to the second aspect of the utility model includes: the wound battery cell 1 according to the first aspect of the utility model; the electrolyte solution (not shown); and the packaging bag 2 for packaging the wound battery cell The core 1 also contains the electrolyte so that the electrolyte wets the first pole piece 11 and the second pole piece 13 of the wound battery cell 1 .

In an embodiment of the electrochemical device according to the present invention, the electrochemical device can be a battery or a capacitor. In one embodiment, the battery may be a lithium-ion battery.

Finally provide the embodiment, comparative example and test results according to the electrochemical device of the present utility model, wherein, the electrochemical device is an example with lithium ion battery, the first pole piece is negative pole piece and the second pole piece is positive pole piece as an example.

Example 1 (refer to Figure 3 and Figure 4)

A preparation of the first pole piece 11 (i.e. negative pole piece)

Graphite (that is, the first active material), conductive carbon, binder styrene-butadiene rubber, and thickener sodium carboxymethylcellulose (CMC) were added to deionized water at a mass ratio of 95.7:1:3.1:0.2, mixed and stirred evenly to prepare To form a negative electrode active material slurry, the negative electrode active material slurry is coated on the front and back surfaces of an 8 μm thick negative electrode current collector copper foil (that is, the first current collector 111), and then rolled and dried (forming the first current collector 111 ). A diaphragm 112), cut to become the negative pole piece.

Preparation of B second pole piece 13 (i.e. positive pole piece)

According to the production method and process of conventional lithium-ion batteries, lithium cobalt oxide (LiCoO ₂ ) (ie, the second active material), conductive carbon, and binder polyvinylidene fluoride (PVDF) were added to N at a mass ratio of 96:2:2. -Mixed and stirred in methylpyrrolidone (NMP) to make positive active material slurry and coated on the positive and negative surfaces of the 12 μm thick positive current collector aluminum foil (that is, the second current collector 131 ), and then rolled and baked dry (forming the second diaphragm 132 ), cut, and become the positive electrode sheet.

C Isolation Film 15 Preparation

A 16μm polypropylene (PP) isolation film is used.

Preparation of D winding cell 1

Manufactured by a winding process, wherein the first tab 12 is copper, the second tab 14 is aluminum, the first tab 12 is welded to the first current collector 111, the second tab 14 is welded to the second current collector 131, The first pole piece 11, the second pole piece 13 and the separator 15 are wound into a bare cell, and the width of the first contact portion 121 of the first tab 12 and the second contact portion 141 of the second tab 14 is 25mm and 45mm in length, the width of the first lead-out part 122 and the second lead-out part 142 are 6mm, the length is 15mm, and the thickness is 0.08mm. The two parts form an inverted T shape. The wound battery core 1 has a width of about 53.5mm and a length of 46.5mm. The widths of the first contact portion 121 and the second contact portion 141 are respectively 1/2 of the width of the wound battery 1 and do not overlap each other. Both the first tab 12 and the second tab 14 are located at the winding end E of the wound cell 1 . At the winding end E of the wound battery 1, the first current collector 111 of the first pole piece 11 is not provided with the first diaphragm 112, and the second current collector 131 of the second pole piece 13 is not provided with the second Diaphragm 132 .

Preparation of Lithium-ion batteries

Put the bare battery cell made by the winding process into the packaging bag 2 made of aluminum-plastic film, inject electrolyte into the packaging bag 2, use lithium hexafluorophosphate (LiPF ₆ ) as lithium salt, ethylene carbonate (EC) and The mass ratio of propylene carbonate (PC), dimethyl carbonate (DMC), and methyl acetate (MA) is 1:1:2:1 to form an electrolyte solution, which is then formed, aged, exhausted, A lithium-ion battery with a width of 55mm, a length of 52mm, and a thickness of 5.2mm was prepared by shaping and other processes, with a capacity of 4.0Ah and a voltage range of 3.0-4.35V.

Example 2 (see Figure 5)

Except following difference, all the other are with embodiment 1.

The difference from Example 1 is that in Step D (preparation of wound battery 1), in Example 2, the first tab 12 is made of nickel, the second tab 14 is made of aluminum, and the first tab 14 is made of aluminum. The ear 12 is welded to the first current collector 111, the second pole ear 14 is welded to the second current collector 131, and the first pole piece 11, the second pole pole piece 13 and the separator 15 are wound into a bare cell. The widths of the first contact portion 121 of the ear 12 and the second contact portion 141 of the second tab 14 are 25 mm and 20 mm respectively, and the length is 45 mm. The width of the first lead-out portion 122 and the second lead-out portion 142 are 5 mm and the length The thickness is 18mm and the thickness is 0.1mm, and the two parts form an inverted T shape. The widths of the first contact portion 121 and the second contact portion 141 are respectively 1/3 of the width of the wound battery 1 and do not overlap each other. Both the first tab 12 and the second tab 14 are located at the winding starting point S of the wound cell 1 . At the winding start point S of the wound battery 1, the first current collector 111 of the first pole piece 11 is not provided with the first diaphragm 112, and the second current collector 131 of the second pole piece 13 is not provided with the first diaphragm 112. Two diaphragms 132.

Example 3 (refer to Figure 3)

Except following difference, all the other are with embodiment 1.

The difference from Example 1 is that in step D (that is, the preparation of wound battery 1), the first tab 12 is made of nickel, the second tab 14 is made of aluminum, and the first tab 12 and the first set The fluid 111 is welded, the second tab 14 is welded to the second current collector 131, the first pole piece 11, the second pole piece 13 and the separator 15 are wound into a bare cell, and the first contact of the first tab 12 The width of the second contact part 141 of the part 121 and the second tab 14 is 46mm and 46mm respectively, and the length is 70mm. The width of the first lead-out part 122 and the second lead-out part 142 is 7mm, the length is 18mm, and the thickness is 0.1mm, the two parts form an inverted T shape. The wound battery core 1 has a width of 93mm and a length of 86mm. The widths of the first contact portion 121 and the second contact portion 141 are respectively 2/5 of the width of the wound battery 1 and do not overlap each other. Both the first tab 12 and the second tab 14 are located at the winding end E of the wound cell 1 . In step E (ie, the preparation of the lithium-ion battery), a lithium-ion battery with a width of 96 mm, a length of 90 mm, and a thickness of 3.6 mm was prepared.

Example 4 (refer to Figure 5)

Except following difference, all the other are with embodiment 1.

The difference from Example 1 is that in Step D (preparation of wound battery 1), in Example 2, the first tab 12 is made of nickel, the second tab 14 is made of aluminum, and the first tab 14 is made of aluminum. The ear 12 is welded to the first current collector 111, the second pole ear 14 is welded to the second current collector 131, and the first pole piece 11, the second pole pole piece 13 and the separator 15 are wound into a bare cell. The width of the first contact portion 121 of the ear 12 and the second contact portion 141 of the second tab 14 are 46mm and 35mm respectively, and the length is 85mm. The thickness is 18mm and the thickness is 0.1mm, and the two parts form an inverted T shape. The wound battery core 1 has a width of 93mm and a length of 86mm. The widths of the first contact portion 121 and the second contact portion 141 are respectively 1/2 of the width of the wound battery 1 and do not overlap each other. Both the first tab 12 and the second tab 14 are located at the winding starting point S of the wound cell 1 . At the winding start point S of the wound battery 1, the first current collector 111 of the first pole piece 11 is not provided with the first diaphragm 112, and the second current collector 131 of the second pole piece 13 is not provided with the first diaphragm 112. Two diaphragms 132.

In step E (ie, the preparation of the lithium-ion battery), a lithium-ion battery with a width of 96 mm, a length of 90 mm, and a thickness of 3.6 mm was prepared.

Comparative example 1 (refer to Figure 8)

Except following difference, all the other are with embodiment 1.

The difference from Example 1 is that in step D (that is, the preparation of the battery cell 1), the first tab 12 is made of nickel, the second tab 14 is made of aluminum, and the first tab 12 is welded to the first current collector 111 , the second tab 14 is welded to the second current collector 131, the first pole piece 11, the second pole piece 13 and the separator 15 are wound into a bare cell, the first pole piece 12 and the second pole piece 14 The width is 6mm, the length is 60mm, and the thickness is 0.1mm. The width and thickness of the lead-out part and the contact part of the two tabs are the same (that is, the two tabs are rectangular). Both the first tab 12 and the second tab 14 are located at the winding starting point S of the wound cell 1 . At the winding start point S of the wound battery 1, the first current collector 111 of the first pole piece 11 is not provided with the first diaphragm 112, and the second current collector 131 of the second pole piece 13 is not provided with the first diaphragm 112. Two diaphragms 132.

Comparative example 2 (refer to Figure 9)

Except following difference, all the other are with embodiment 1.

The difference from Example 1 is that in step D (that is, the preparation of the battery cell 1), the first tab 12 is nickel alloy, the second tab 14 is aluminum, and the first tab 12 and the first current collector 111 Welding, the second tab 14 is welded with the second current collector 131, the first pole piece 11, the second pole piece 13 and the separator 15 are wound into a bare cell, the first tab 12 and the second tab 14 The width is 6mm, the length is 60mm, and the thickness is 0.05mm, and the width and thickness of the lead-out part and the contact part of the two tabs are the same (that is, the two tabs are rectangular). The first tab 12 is located at the winding start point S of the wound cell 1 , and the second tab 14 is located at the winding end point E of the wound cell 1 . At the winding start S and the winding end E of the wound battery 1, the first collector 111 of the first pole piece 11 is not provided with the first diaphragm 112, and the second collector of the second pole piece 13 The fluid 131 is not provided with a second membrane 132 .

Comparative example 3 (refer to Figure 7)

Except following difference, all the other are with embodiment 1.

The difference from Example 1 is that in step D (that is, the preparation of the battery cell 1), the first tab 12 is nickel alloy, the second tab 14 is aluminum, and the first tab 12 and the first current collector 111 Welding, the second tab 14 is welded with the second current collector 131, the first pole piece 11, the second pole piece 13 and the separator 15 are wound into a bare cell, the first tab 12 and the second tab 14 The width is 3mm, the length is 60mm, and the thickness is 0.12mm. The width and thickness of the lead-out part and the contact part of the two tabs are the same (that is, the two tabs are rectangular). Both the first tab 12 and the second tab 14 are located at the winding end E of the wound cell 1 .

Comparative example 4 (refer to Figure 6)

The difference from Example 1 is that in step D (that is, the preparation of the battery cell 1), the first tab 12 is nickel alloy, the second tab 14 is aluminum, and the first tab 12 and the first current collector 111 Welding, the second tab 14 is welded to the second current collector 131, the first pole piece 11, the second pole piece 13 and the separator 15 are wound into a bare cell, the first lead-out part 122 of the first tab 12 The width of the first tab 12 is 6 mm, and the length is 10 mm; the width of the first contact portion 121 of the first tab 12 is 25 mm, the length is 45 mm, and the thickness is 0.05 mm. The width of the second tabs 14 is 6mm, the length is 60mm, and the thickness is 0.05mm. The first tab 12 is located at the winding start point S of the wound cell 1 , and the second tab 14 is located at the winding end point E of the wound cell 1 . At the winding start S and the winding end E of the wound battery 1, the first collector 111 of the first pole piece 11 is not provided with the first diaphragm 112, and the second collector of the second pole piece 13 The fluid 131 is not provided with a second membrane 132 .

Get the above-mentioned each embodiment, the lithium-ion battery in the comparative example carries out charging and discharging test with 1C/1C, check the lithium-ion battery deformation situation after every 100 times of charging and discharging, and its result is recorded in the following table 1; Take the above-mentioned each embodiment separately 1. After the lithium-ion battery in the comparative example was fully charged, it was stored at 60° C., and the deformation of the lithium-ion battery was checked after 15 days. The results were recorded in Table 1 below. In addition, it was discharged at a rate of 10C to test the discharge capacity retention rate of the battery.

The test result of table 1 embodiment 1-4 and comparative example 1-4

It can be seen from Table 1 that compared with the prior art, the lithium-ion battery of the present invention will not be distorted and deformed when used under normal conditions, which greatly reduces the risk of deformation during the use of the lithium-ion battery. At the same time, the internal resistance of the battery is also reduced by about 20%, and the 10C discharge capacity retention rate is increased by more than 10%. In currently commercialized lithium-ion batteries, deformation is more likely to occur when the width and length of the battery are increased. Therefore, we apply this technology to batteries with relatively large width and length to further verify the effect of its application, such as Example 3 and Example 4, the proportion of deformation after cycling is much smaller than that of the small battery before improvement, such as Comparative Example 1, proving This technique works universally with batteries of different sizes.

Claims (10)

1. A winding battery cell (1), comprising: The first pole piece (11), including a first current collector (111) and a first diaphragm (112) containing a first active material disposed on the surface of the first current collector (111); The first tab (12), arranged and electrically connected to the first current collector (111) of the first pole piece (11); The second pole piece (13), opposite to the polarity of the first pole piece (11), includes a second current collector (131) and a second electrode containing a second active material arranged on the surface of the second current collector (131). Diaphragm (132); The second tab (14), arranged and electrically connected to the second current collector (131) of the second pole piece (13); and An isolation film (15), arranged between the first pole piece (11) and the second pole piece (13); Wherein, the first pole piece (11), the separator (15) and the second pole piece (13) are sequentially wound to form a wound battery cell (1); At the beginning (S) and winding end (E), the first current collector (111) of the first pole piece (11) is not provided with the first diaphragm (112), and the second pole piece (13) The current collector (131) is not provided with the second diaphragm (132); It is characterized in that, The first tab (12) is set at the position of the first current collector (111) of the first pole piece (11) and the second tab (14) is set at the second current collector (131) of the second pole piece (13). ) at the start (S) of the winding cell (1) or at the end (E) of the winding cell (1); The first tab (12) has a first contact portion (121) in contact with the first current collector (111) and a first lead-out portion (122) exposing the first current collector (111), the first contact portion (121) The length of the first contact part (121) is 1/3 to 1/2 of the width of the wound electric core (1); The second tab (14) has a second contact portion (141) in contact with the second current collector (131) and a second lead-out portion (142) exposing the second current collector (131), the second contact portion (141) The length of the second contact part (141) is 1/3 to 1/2 of the width of the wound electric core (1); Wherein, the first contact portion (121) of the first tab (12) and the second contact portion (141) of the second tab (14) are misaligned with each other, so as to ensure that the first tab ( The first contact portion (121) of 12) and the second contact portion (141) of the second tab (14) do not overlap each other in the width direction of the electric core. 2. The wound battery cell (1) according to claim 1, characterized in that, The first tab (12) is welded to the first current collector (111) of the first pole piece (11); The second tab (14) is welded to the second current collector (131) of the second pole piece (13). 3. The wound battery core (1) according to claim 1, characterized in that the materials of the first tab (12) and the second tab (14) are pure aluminum strip, pure copper strip, pure nickel Strip, or surface-treated aluminum strip, copper strip, nickel strip, or copper alloy, nickel alloy, copper-plated, nickel-plated metal strip. 4. The wound battery core (1) according to claim 1, characterized in that the first lead-out part (122) of the first tab (12) and the second lead-out part of the second tab (14) (142) has a width of 3mm-10mm and a length of 10mm-18mm. 5. The wound battery core (1) according to claim 1, characterized in that the thickness of the first tab (12) and the second tab (14) is 0.05mm-0.15mm. 6. The wound battery cell (1) according to claim 1, characterized in that, The first contact part (121) and the first lead-out part (122) of the first tab (12) form an E-shape or an L-shape; The second contact portion (141) and the second lead-out portion (142) of the second tab (14) form an E-shape or an L-shape. 7. The wound battery cell (1) according to claim 1, characterized in that, The width of the first contact portion (121) of the first tab (12) is the same as or different from the width of the second contact portion (141) of the second tab (14); The length of the first contact portion (121) of the first tab (12) is the same as or different from the length of the second contact portion (141) of the second tab (14). 8. An electrochemical device comprising: The wound battery cell (1) according to any one of claims 1-7; electrolyte; and A packaging bag (2), encapsulating the wound electric core (1) and containing electrolyte so that the electrolyte can infiltrate the first pole piece (11) and the second pole piece (13) of the wound electric core (1). 9. The electrochemical device according to claim 8, wherein the electrochemical device is a battery or a capacitor. 10. The electrochemical device according to claim 9, wherein the battery is a lithium ion battery.