CN219677331U

CN219677331U - Roll up core structure and lithium ion battery

Info

Publication number: CN219677331U
Application number: CN202321189910.XU
Authority: CN
Inventors: 朱炳阳; 陈杰; 郑明清
Original assignee: Zhejiang Liwei Energy Technology Co ltd
Current assignee: Zhejiang Liwei Energy Technology Co ltd
Priority date: 2023-05-17
Filing date: 2023-05-17
Publication date: 2023-09-12
Anticipated expiration: 2033-05-17

Abstract

The utility model belongs to the technical field of battery production and manufacturing, and in particular relates to a winding core structure and a lithium ion battery, which comprise a winding core body, wherein the winding core body comprises a first pole piece, a second pole piece and a diaphragm, and the first pole piece, the diaphragm and the second pole piece are sequentially overlapped and wound to form the winding core body; the winding core comprises a winding core body, wherein two opposite ends of the winding core body are provided with side bending areas, a first empty foil position is arranged at a part of the first pole piece corresponding to the side bending areas, a second empty foil position is arranged at a part of the second pole piece corresponding to the side bending areas, and pole lugs are welded at the first empty foil position and the second empty foil position. According to the utility model, the cycle performance of the battery can be improved by optimizing the welding position of the tab.

Description

Roll up core structure and lithium ion battery

Technical Field

The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to a winding core structure and a lithium ion battery.

Background

Lithium batteries are widely used in various high-end digital fields due to their excellent performance, and in recent years, the energy density and cycle performance of lithium batteries have gradually reached bottlenecks.

The square winding type battery has the advantages that the lug is arranged in the middle of the battery core, the lug and the pole piece generate thickness difference, the problem of lithium precipitation is unavoidable during circulation, the circulation performance is deteriorated, the digital lithium battery has higher thickness requirements, but larger allowance exists in the width direction, and the circulation capacity and the capacity density of the battery are lower.

Disclosure of Invention

The utility model aims at: aiming at the defects of the prior art, on one hand, the coil core structure is provided, and the cycle performance of the battery can be improved by optimizing the welding position of the tab.

In order to achieve the above purpose, the present utility model adopts the following technical scheme:

the winding core structure comprises a winding core body, wherein the winding core body comprises a first pole piece, a second pole piece and a diaphragm, and the first pole piece, the diaphragm and the second pole piece are sequentially overlapped and wound to form the winding core body; the winding core comprises a winding core body, wherein two opposite ends of the winding core body are provided with side bending areas, a first empty foil position is arranged at a part of the first pole piece corresponding to the side bending areas, a second empty foil position is arranged at a part of the second pole piece corresponding to the side bending areas, and pole lugs are welded at the first empty foil position and the second empty foil position.

Preferably, in the side bending region of the winding core body, the first pole piece and the second pole piece are sequentially arranged to form a multi-layer structure.

Preferably, at least one layer of the first pole piece is provided with the first empty foil position, and at least one layer of the second pole piece is provided with the second empty foil position.

Preferably, the first pole piece or the second pole piece is provided with a side edge part and two arc parts at the corresponding side edge bending areas, and the two arc parts are respectively arranged at two ends of the side edge part.

Preferably, the radius of the arc part is larger than the width of the tab, and the tab is welded to the side part.

Preferably, the radius of the arc part is smaller than the width of the tab, the difference between the half perimeter of the arc part and the width of the tab is larger than 2m, and the tab is at least partially welded to the arc part.

Preferably, one end of the first pole piece is located at the innermost ring of the winding core body, and the other end of the first pole piece is located at the outermost ring of the winding core body.

Preferably, the other end of the first pole piece is located on the outer peripheral surface of the winding core body, and the first pole piece and the diaphragm are arranged around the winding core body.

Preferably, the cross section of the winding core body is of a square structure.

On the other hand, a lithium ion battery is provided, which comprises the winding core structure.

One of the above technical solutions has the following beneficial effects

According to the utility model, the lug on the plane of the inner ring of the pole piece is transferred to the side bending area of the winding core body, namely, the increased thickness of the battery core is transferred to the width, so that the energy density of the battery core is improved, obvious bulges at the positions of the battery surface corresponding to the lug are avoided, the flatness and the aesthetic degree of the battery core are improved, in addition, the problem of poor thickness of the pole piece and the lug is relieved, and the situation that lithium is separated due to the fact that the pole piece at the edge of the lug is not tightly attached and the circulation performance is influenced is avoided.

Drawings

Features, advantages, and technical effects of exemplary embodiments of the present utility model will be described below with reference to the accompanying drawings.

Fig. 1 is a schematic structural view of the present utility model.

Wherein reference numerals are as follows:

10-winding core body;

1-a first pole piece;

2-a second pole piece;

3-a separator;

4-side bending region;

5-a first empty foil position;

6-a second empty foil position;

7-electrode lugs;

8-side edge portions;

9-arc portion.

Detailed Description

Certain terms are used throughout the description and claims to refer to particular components. Those of skill in the art will appreciate that a hardware manufacturer may refer to the same component by different names. The description and claims do not take the form of an element differentiated by name, but rather by functionality. As used throughout the specification and claims, the word "comprise" is an open-ended term, and thus should be interpreted to mean "include, but not limited to. By "substantially" is meant that within an acceptable error range, a person skilled in the art can solve the technical problem within a certain error range, substantially achieving the technical effect.

Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the present utility model, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

The present utility model will be described in further detail below with reference to the drawings, but is not limited thereto.

Embodiment one

Because the lug of the square winding type battery is arranged in the middle of the battery core, the lug and the pole piece generate thickness difference, the problem of lithium precipitation is inevitably generated during circulation, the circulation performance is deteriorated, the digital lithium battery has higher requirements on thickness, but larger allowance exists in the width direction, and the circulation capacity and the capacity density of the battery are lower.

The winding core structure comprises a winding core body 10, wherein the winding core body 10 comprises a first pole piece 1, a second pole piece 2 and a diaphragm 3, and the first pole piece 1, the diaphragm 3 and the second pole piece 2 are sequentially overlapped and wound to form the winding core body 10; the two opposite ends of the winding core body 10 are provided with side bending areas 4, a first empty foil position 5 is arranged at a part of the first pole piece 1 corresponding to the side bending areas 4, a second empty foil position 6 is arranged at a part of the second pole piece 2 corresponding to the side bending areas 4, and pole lugs 7 are welded at the first empty foil position 5 and the second empty foil position 6. According to the utility model, the lug on the plane of the inner ring of the pole piece is transferred to the side bending area 4 of the winding core body 10, namely, the increased thickness of the battery cell of the lug 7 is transferred to the width, so that the energy density of the battery cell can be improved, obvious bulges at the positions of the battery surface corresponding to the lug can be avoided, the flatness and the aesthetic degree of the battery cell can be improved, in addition, the problem of poor thickness of the pole piece and the lug can be relieved, and the situation that lithium is separated due to the fact that the pole piece at the edge of the lug is not tightly attached is avoided, and the cycle performance is influenced.

In the winding core structure according to the present utility model, in the side bending region 4 of the winding core body 10, the first pole piece 1 and the second pole piece 2 are sequentially arranged to form a multi-layer structure. In this embodiment, after the first pole piece 1, the diaphragm 3, and the second pole piece 2 are wound, the first pole piece 1, the diaphragm 3, and the second pole piece 2 are sequentially stacked, and in the thickness direction of the pole pieces, the first pole piece 1 of the outer layer, the first pole piece 1 of the sub-inner layer, and the first pole piece 1 of the innermost layer can be understood as being arranged to form a multilayer structure, and similarly, the second pole piece 2 also forms a multilayer structure at the opposite end.

In the winding core structure according to the present utility model, a side portion 8 and two arc portions 9 are provided at the position of the first pole piece 1 or the second pole piece 2 corresponding to the side bending region 4, and the two arc portions 9 are provided at both ends of the side portion 8, respectively. In this embodiment, the side portion 8 may be understood as a portion of the first pole piece 1 or the second pole piece 2 perpendicular to the horizontal plane, where the first pole piece 1 or the second pole piece 2 is connected to the upper end and the lower end of the side portion 8, respectively, and the first pole piece 1 on the outer layer and the first pole piece 1 on the inner layer may have the above-mentioned structure, and the second pole piece 2 may also have the above-mentioned structure, which is not limited herein.

In the core structure according to the utility model at least one layer of the first pole piece 1 is provided with a first empty foil site 5 and at least one layer of the second pole piece 2 is provided with a second empty foil site 6. In this embodiment, there are the first pole piece 1 of the outer layer, the first pole piece 1 of the sub-inner layer, and the first pole piece 1 of the innermost layer in the thickness direction of the pole pieces, where one or two layers of the first pole pieces 1 may be provided with the first empty foil position 5, which is conducive to increasing the number of tabs, thereby improving the current capacity of the battery, and similarly, one or two layers of the second pole pieces 1 may be provided with the second empty foil position 6, which may be adjusted according to the size of the actual winding core body 10, where no limitation is made, where the tab welding position is preprocessed in advance to weld the first empty foil position 5 and the second empty foil position 6, and then the tab 7 is welded, where the first empty foil position 5 and the second empty foil position 6 are matched with the width of the tab 7.

In the winding core structure according to the present utility model, the radius of the circular arc portion 9 is larger than the width of the tab 7, and the tab 7 is welded to the side portion 8. When the tab 7 is welded on the selected layer, if the radius of the arc part 9 is larger than the width of the tab 7, that is, the radius of the side R is larger than the width of the tab, the tab 7 can be attached to the side bending area 4, and the tab 7 is welded on the side part 8.

In the core structure according to the utility model, the core body 10 has a substantially square structure in cross section,

the working principle of the utility model is as follows:

according to the utility model, the lug on the plane of the inner ring of the pole piece is transferred to the side bending area 4 of the winding core body 10, namely the thickness of the battery cell increased by the lug 7 is transferred to the width, so that the space 60-150 mu m on the thickness of the lug can be saved, the theoretical energy density is improved by 1-2%, the energy density of the battery cell is improved, and the residual width is usually more than 1000 mu m.

The welding position is treated in advance to form a welding empty foil position, then the electrode lugs are welded and wound into a battery, and the square winding type lithium ion battery can be obtained by designing the welding position, pretreating the side empty foil position, transferring the electrode lugs for welding and the like.

Second embodiment

Unlike the first embodiment, the following is: the radius of the arc part 9 of the present embodiment is smaller than the width of the tab 7, the difference between the half perimeter of the arc part 9 and the width of the tab 7 is greater than 2m, and the tab 7 is welded at least partially to the arc part 9. In the process of selecting which layer to weld the tab 7, if the radius of the arc part 9 is smaller than the width of the tab 7, that is, the radius R angle is smaller than the width of the tab, the difference between the half perimeter of the arc part 9 and the width of the tab 7 is required to be larger than 2m, that is, the half perimeter R of the side edge is larger than the width +2m of the tab, the tab 7 is welded at least partially to the arc part 9, so that the tab welding area is transferred to the upper semicircle or the lower semicircle of the bending area, the tab attaching bending area can be met, and then the battery is wound.

Other structures are the same as those of the first embodiment, and will not be described here again.

Embodiment III

Unlike the first embodiment, the following is: one end of the first pole piece 1 of the present embodiment is located at the innermost ring of the winding core body 10, the other end of the first pole piece 1 is located at the outermost ring of the winding core body 10, and can be adjusted according to actual production requirements, without limitation, and the other end of the first pole piece 1 is located at the outer peripheral surface of the winding core body 10, and is disposed around the winding core body 10 with the diaphragm 3, so as to play a role in wrapping the outer peripheral surface of the winding core body 10.

Lithium ion battery

The utility model comprises the winding core structures of the first to third embodiments.

The winding core structure of the utility model can be used for an electric core, and the winding core body 10 can comprise at least two pole pieces which are mutually overlapped and have opposite polarities, wherein the pole pieces with opposite polarities are respectively a positive pole piece and a negative pole piece of a battery. In order to avoid short circuit between the positive pole piece and the negative pole piece, a diaphragm is arranged between every two adjacent pole pieces, and the pole pieces with opposite polarities are electrically isolated through the diaphragm. The pole piece comprises a current collector and an active substance coated on the surface of the current collector, the surface of the pole piece is provided with an empty foil area, the thickness of the empty foil area is smaller than that of the middle normal area, wherein the current collector is exposed on the surface of the empty foil area of the pole piece and is welded with the end part of the pole lug, the pole lug groove is arranged in the empty foil area of the pole piece, the shape of the pole lug groove is matched with that of the pole lug, the empty foil area is positioned in the edge area of the pole piece, the head of the pole piece can be positioned in any position in the middle of the pole piece, and the outside of the edge area of the current collector is provided with an active substance coverage area. The tab comprises a positive tab and a negative tab, namely a tab for a positive plate and a tab for a negative plate.

The current collector is a structure or a part for collecting current, is mainly a metal foil such as a copper foil, an aluminum foil, a composite current collector and the like on the lithium ion battery, and is mainly used for collecting the current generated by active substances of the battery so as to form larger current to be output outwards, and the current collector and the active substances are required to be fully contacted and have smaller internal resistance.

The connection mode of the pole piece and the pole lug comprises but is not limited to ultrasonic welding, laser welding, soldering, conductive adhesive tape and the like, and can also be other fixing modes.

In order to avoid short circuit between the positive pole piece and the negative pole piece, a diaphragm 3 is arranged between every two adjacent pole pieces, and pole pieces with opposite polarities are electrically isolated through the diaphragm 3. The polarities of the first pole piece 1 and the second pole piece 2 are opposite, and the first pole piece 1 and the second pole piece 2 are mutually overlapped.

Specifically, the first pole piece 1 may be an anode piece, and the second pole piece 2 may be a cathode piece; alternatively, the first electrode sheet 1 may be a negative electrode sheet, and the second electrode sheet 2 may be a positive electrode sheet, without limitation.

The first pole piece 1 and the second pole piece 2 are one, and the first pole piece 1, the diaphragm 3 and the second pole piece 2 which are sequentially overlapped are wound around a winding center to form a winding structure.

In some embodiments, the winding core further comprises a tail-over glue, wherein the end part of the tail-over glue is adhered to the tail part of the first pole piece 1, and the tail-over glue surrounds the outer side of the winding core. In this embodiment, the tail of the first pole piece 1 is fixed by the ending glue, so as to prevent the probability of loosening of the outer side of the winding core 4, and the ending glue also has an insulating effect, so as to prevent the short circuit of the battery caused by the contact of the first pole piece 1 and the second pole piece 2.

The battery with the winding core structure can also be used for an electric device, and the electric device can be a mobile phone, portable equipment, a notebook computer and the like.

Variations and modifications of the above embodiments will occur to those skilled in the art to which the utility model pertains from the foregoing disclosure and teachings. Therefore, the present utility model is not limited to the above-described embodiments, but is intended to be capable of modification, substitution or variation in light thereof, which will be apparent to those skilled in the art in light of the present teachings. In addition, although specific terms are used in the present specification, these terms are for convenience of description only and do not limit the present utility model in any way.

Claims

1. The winding core structure is characterized by comprising a winding core body (10), wherein the winding core body (10) comprises a first pole piece (1), a second pole piece (2) and a diaphragm (3), and the first pole piece (1), the diaphragm (3) and the second pole piece (2) are sequentially overlapped and wound to form the winding core body (10);

the winding core comprises a winding core body (10), wherein two opposite ends of the winding core body (10) are provided with side bending areas (4), a first empty foil position (5) is arranged at a part of the first pole piece (1) corresponding to the side bending areas (4), a second empty foil position (6) is arranged at a part of the second pole piece (2) corresponding to the side bending areas (4), and pole lugs (7) are welded at the first empty foil position (5) and the second empty foil position (6).

2. A winding core structure according to claim 1, wherein: in the side bending area (4) of the winding core body (10), the first pole piece (1) and the second pole piece (2) are sequentially arranged to form a multi-layer structure.

3. A winding core structure according to claim 2, wherein: at least one layer of first pole piece (1) is provided with a first empty foil position (5), and at least one layer of second pole piece (2) is provided with a second empty foil position (6).

4. A winding core structure according to claim 1, wherein: the first pole piece (1) or the second pole piece (2) is provided with a side edge part (8) and two arc parts (9) at the position corresponding to the side edge bending area (4), and the two arc parts (9) are respectively arranged at two ends of the side edge part (8).

5. A winding core structure according to claim 4, wherein: the radius of the arc part (9) is larger than the width of the lug (7), and the lug (7) is welded to the side part (8).

6. A winding core structure according to claim 4, wherein: the radius of the arc part (9) is smaller than the width of the lug (7), the difference between the half perimeter of the arc part (9) and the width of the lug (7) is larger than 2m, and the lug (7) is at least partially welded on the arc part (9).

7. A winding core structure according to claim 1, wherein: one end of the first pole piece (1) is located at the innermost ring of the winding core body (10), and the other end of the first pole piece (1) is located at the outermost ring of the winding core body (10).

8. A winding core structure according to claim 7, wherein: the other end of the first pole piece (1) is positioned on the outer peripheral surface of the winding core body (10), and the first pole piece and the diaphragm (3) are arranged around the winding core body (10).

9. A winding core structure according to claim 1, wherein: the cross section of the winding core body (10) is of a square structure.

10. A lithium ion battery, characterized in that: a winding core structure comprising the winding core structure of any one of claims 1-9.