Square-shell lithium battery roll core and square-shell lithium battery

Abstract

The utility model provides a square-shell lithium battery roll core and a square-shell lithium battery, and belongs to the field of square-shell lithium batteries. The square-shell lithium battery roll core comprises at least two roll core main bodies which are arranged side by side; the adhesive tape is coated on the peripheral surface of each roll core main body; the peripheral surfaces of every two adjacent roll core bodies comprise planes, the planes of every two adjacent roll cores are tightly attached to each other, and each plane is formed by splicing a first part and a second part; through holes are evenly formed in the adhesive tape, and the portion, wrapping the tightly-attached planes, of the adhesive tape passes through the first portion or the second portion and ends at the boundary of the first portion and the second portion. The adhesive tape completely covers the periphery of the square-shell battery core and is provided with the through holes, so that the tension of the outer ring of the roll core is improved through the adhesive tape, the increase of the distance between positive and negative pole pieces in the circulation process is remarkably limited, a good capillary phenomenon is maintained, the liquid retention capacity of the outer ring pole pieces is improved, and black spot lithium precipitation on the circulation interface of the outer ring of the roll core in the long-term circulation process is favorably reduced; the cycle life and the safety performance of the battery cell are obviously improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to square shell lithium cell technical field especially, relates to a square shell lithium cell roll core and square shell lithium cell. BACKGROUND

[0002] Lithium battery, also known as lithium ion battery, is a kind of rechargeable battery which completes the charge-discharge process by moving lithium ions between positive and negative electrodes. Lithium battery has the advantages of high energy density, high discharge power, long cycle life, no memory effect and environmental friendliness. Due to its excellent performance, lithium ion battery has become an indispensable energy storage solution in modern life. It is widely used in electric vehicles, backup power systems and microgrid energy storage systems. Up to now, no matter in the consumer direction, power direction or energy storage direction, users have continuously improved the requirements for lithium ion battery safety performance, cycle life and use cost.

[0003] Power lithium battery contains roll core, electrolyte, shell, cover plate and other structures. For example, a new type of large aluminum shell roll core structure disclosed in Chinese patent CN208028159U belongs to square shell lithium battery roll core structure. As a kind of high safety and high efficiency lithium ion battery, square shell lithium battery has been widely studied in recent years. During the battery cycle process, the electrolyte in the shell will climb from the bottom of the roll core to the top of the cell under the action of capillary. However, due to the design of the existing square shell lithium battery winding structure, the capillary action of the outermost circle is weak, which leads to poor wettability of the pole piece, and there is blackboard lithium precipitation phenomenon at the interface of the outermost circle during the multiple cycle process of the cell, which leads to rapid capacity decay of the cell. More serious phenomenon is that lithium is precipitated and crystallized to pierce and cause thermal runaway. Finally, the cycle life of the cell is not good, which is not as good as the laminated battery, and lacks corresponding competitiveness. SUMMARY

[0004] Therefore, the utility model provides a square shell lithium battery roll core and square shell lithium battery to solve the problem that the capillary action of the outermost circle of the existing square shell lithium battery is weak due to the design of its own winding structure, which leads to poor wettability of the pole piece.

[0005] The technical scheme of the utility model is realized as follows: the utility model provides a square shell lithium battery roll core, which comprises at least two roll core bodies arranged side by side, and adhesive tape wrapped on the outer circumferential surface of each roll core body. The outer circumferential surface of each roll core body comprises a plane, and the planes of adjacent roll core bodies are arranged in close contact with each other. The plane is composed of a first part and a second part. The adhesive tape is provided with through holes, and the part of the adhesive tape wrapped on the planes in close contact with each other passes through the first part or the second part and ends at the boundary line between the first part and the second part.

[0006] On the basis of the above technical scheme, preferably, the plane is equally divided into the first part and the second part.

[0007] Preferably, the first part and the second part are square.

[0008] Preferably, the outer circumferential surface of the core body is formed by alternately splicing two planes and two arc surfaces, and the adhesive tape is provided with the through hole only in the part covering the plane.

[0009] Preferably, the through hole is a polygonal hole or an elliptical hole.

[0010] Preferably, the inner diameter of the through hole is not greater than 5 mm.

[0011] Preferably, the distance between the outer edges of adjacent through holes is 10-20 mm.

[0012] Preferably, the total area of the through holes on the adhesive tape covering each core body is 30%-70% of the total area of the adhesive tape.

[0013] Preferably, the thickness of the adhesive tape is not greater than 0.1 mm.

[0014] In another aspect, the utility model also provides a square shell lithium battery adopting the square shell lithium battery core.

[0015] The square shell lithium battery core and the square shell lithium battery of the utility model have the following advantages

[0016] Advantages:

[0017] (1) In the utility model, the adhesive tape is completely covered on the outer periphery of the square shell core, and the through hole is arranged on the adhesive tape, the adhesive tape is used to improve the tension of the outer ring of the core, the distance between the positive and negative electrode plates in the circulation process is significantly limited, the capillary phenomenon is maintained, the liquid retention capacity of the outer ring of the electrode plate is improved, the black spot lithium precipitation of the circulation interface of the outer ring of the core in the long-term circulation process is reduced, and the cycle life and safety performance of the core are significantly improved.

[0018] (2) In the utility model, the termination positions of the adhesive tapes covering the two core bodies on the close-fitting plane are aligned and do not overlap, so that the additional thickness of the core is not increased.

[0019] (3) In the utility model, the thickness of the adhesive tape is not greater than 0.1 mm, so that the overall thickness of the core is not affected. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0021] Figure 1 It is a perspective view of the square shell lithium battery roll core of the present application.

[0022] Figure 2 It is a perspective view of the single roll core body and adhesive tape of the present application.

[0023] Figure 3 It is a non-tightly flat view of the two roll cores of the present application.

[0024] Figure 4 It is a tightly flat view of the two roll cores of the present application.

[0025] In the figure: 1, roll core body; 101, flat surface; 1011, first part; 1012, second part; 102, curved surface; 2, adhesive tape; 201, through hole. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below, obviously, the described embodiments are only some embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0027] As shown in Figure 1 , in combination with Figure 3 and Figure 4 , the present application is a square shell lithium battery roll core, which comprises a roll core body 1 and an adhesive tape 2.

[0028] Among them, at least two roll core bodies 1 are arranged side by side. The outer peripheral surface of each of the two adjacent roll core bodies 1 comprises a flat surface 101, and the flat surfaces 101 of the two adjacent roll cores are arranged tightly against each other, and the flat surface 101 is spliced by a first part 1011 and a second part 1012.

[0029] The adhesive tape 2 is made of flexible material, and the main material is PET, but it also includes PP, PC, PE, PVC, PS, POM, PV, PA, ABS and other high polymer materials, and the single surface is coated with acrylic, polymethyl methacrylate and other material adhesives. The adhesive tape 2 is wrapped on the outer circumferential surface of each roll core body 1; the through holes 201 are uniformly arranged on the adhesive tape 2, and the through holes 201 serve as flow holes to enable the electrolyte to fully flow into and out of the roll core. The part of the adhesive tape 2 wrapped on the mutually close planes 101 passes through the first part 1011 or the second part 1012 and ends at the boundary line between the first part 1011 and the second part 1012.

[0030] When the roll core body 1 is not pasted with the adhesive tape 2, the tension is too small, the gap between the positive and negative electrode plates of the outer ring is too large, and the electrolyte at the bottom of the bare battery core is difficult to climb to the large surface and the top end of the electrode plate by capillary action (the capillary phenomenon is related to the inner diameter of the capillary tube, the smaller the inner diameter, the more obvious the capillary phenomenon; when the inner diameter of the tube is too large, the height of the liquid rising is very small). The height of the liquid rising and falling in the capillary phenomenon can be determined by the following formula:

[0031]

[0032] Wherein, r is the radius of the tube; p is the density of the liquid, and d is the surface tension; q is the intersection angle between the liquid surface and the tube wall, and other conditions remain unchanged. The smaller r is, the larger h is. Therefore, the use of the adhesive tape 2 can improve the tension of the outer ring of the roll core body 1, significantly limit the increase of the distance between the positive and negative electrode plates during the circulation process, maintain good capillary phenomenon, improve the liquid retention capacity of the outer ring electrode plate, avoid the black spots and lithium precipitation phenomenon of the outer ring after multiple circulations, and significantly improve the cycle life and safety performance of the battery core. At the same time, since two roll core bodies 1 are usually arranged in parallel and close to each other in a square battery, only one layer of adhesive tape can be arranged between the two roll core bodies 1. Therefore, the plane 101 close to the two roll core bodies 1 is divided into two parts, and the two adhesive tapes 2 wrapping the two roll core bodies 1 only wrap the first part 1011 or the second part 1012. The terminal parts of the two adhesive tapes 2 are aligned and spliced at the boundary line between the first part 1011 and the second part 1012 without overlapping, so that the thickness of the roll core body 1 is not increased.

[0033] In Figure 4 In a preferred embodiment shown in the figure, the plane 101 is equally divided into the first part 1011 and the second part 1012. The areas of the first part 1011 and the second part 1012 can be different, or the first part 1011 and the second part 1012 can have different shapes but the same area. As long as the parts of the two adhesive tapes 2 pasted on the first part 1011 and the second part 1012 are aligned and spliced into a whole without overlapping, the thickness of the roll core body 1 will not be increased, and the improvement of the wettability of the battery core electrode plate can be ensured.

[0034] InFigure 4 In a preferred embodiment shown, the first part 1011 and the second part 1012 are both square. The boundary line between the two can also not be a straight line, but can be an oblique line or a curve, but in order to facilitate the assembly and manufacture of the battery cell, the boundary line between the two is usually a straight line perpendicular to the bottom surface of the winding core body 1, so that the first part 1011 and the second part 1012 are square.

[0035] In Figure 1 In a preferred embodiment shown, the outer peripheral surface of the winding core body 1 is alternately spliced by two planes 101 and two arc surfaces 102. Since the arc surface 102 itself has a large tension, the adhesive tape 2 only opens a through hole 201 in the part covering the plane 101, which can also ensure the improvement of the wetting effect of the battery cell tab.

[0036] In Figure 2 In a preferred embodiment shown, the through hole 201 is a polygonal hole or an elliptical hole, such as a rhombus, a triangle or a circle, which has no effect on the improvement of the wetting effect of the battery cell tab.

[0037] In Figure 2 In a preferred embodiment shown, the inner diameter of the through hole 201 is not greater than 5mm, which avoids the tearing of the adhesive tape 2 caused by the too large hole diameter of the through hole 201. The inner diameter of the through hole 201 within 5mm can make the electrolyte fully flow into and out of the winding core body 1.

[0038] In Figure 2 In a preferred embodiment shown, the distance between the outer edges of adjacent through holes 201 is 10-20mm, which ensures the structural strength of the adhesive tape 2 and avoids its tearing.

[0039] In Figure 1 In a preferred embodiment shown, the total area of the through holes 201 on the adhesive tape 2 covering each winding core body 1 is 30%-70% of the total area of the adhesive tape 2, so that sufficient electrolyte can flow into and out of the winding core body 1.

[0040] In Figure 1 In a preferred embodiment shown, the thickness of the adhesive tape 2 is not greater than 0.1mm, so as to ensure that the thickness of the adhesive tape 2 has no effect on the overall thickness of the battery cell.

[0041] As Figure 1 As shown, the utility model discloses a square shell lithium battery adopts the square shell lithium battery winding core of any embodiment described above.

[0042] The above only describes the preferred embodiment of the utility model and does not limit the utility model, and any modification, equivalent replacement, improvement, etc. within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A square can lithium battery roll core, characterized in that, The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core.

2. The prismatic lithium battery cell of claim 1, wherein: The application relates to a square lithium battery roll core.

3. The prismatic lithium battery cell of claim 1, wherein: The application relates to a square lithium battery roll core.

4. The prismatic lithium battery cell of claim 1, wherein: The application relates to a square lithium battery roll core.

5. The prismatic lithium battery cell of claim 1, wherein: The application relates to a square lithium battery roll core.

6. The prismatic lithium battery cell of claim 1, wherein: The application relates to a square lithium battery roll core.

7. The prismatic lithium battery cell of claim 1, wherein: The application relates to a square lithium battery roll core.

8. The prismatic lithium battery cell of claim 1, wherein: The application relates to a square lithium battery roll core.

9. The prismatic lithium battery cell of claim 1, wherein: The application relates to a square lithium battery roll core.

10. A prismatic lithium battery, characterized by: The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The application relates to a square lithium battery roll core. The

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