Roll core structure and battery

Abstract

The utility model provides a roll core structure and a battery. The roll core structure comprises a positive plate, a diaphragm and a negative plate, the positive plate, the diaphragm and the negative plate are jointly wound to form a roll core, the diaphragm is positioned between the positive plate and the negative plate, two flattening surfaces and two bending surfaces are formed on the outer side surface of the roll core, the flattening surfaces and the bending surfaces are alternately connected, and the roll core structure further comprises a binding colloid, the binding colloid is attached to the two bent surfaces respectively and completely covers the bent surfaces, and the length of the binding colloid is larger than or equal to the width of the positive plate. When the battery is used, the binding colloid ties the bending surface of the roll core structure, that is, the binding colloid ties the crease of the roll core, so that the effect of inhibiting deformation of the crease of the roll core is achieved, the problem of gap increase at the crease of the roll core is inhibited, the problem of black spot lithium precipitation at the crease of the roll core is further inhibited, the cycle retention rate of the battery is improved, and the service life of the battery is prolonged.

Description

Technical Field

[0001] The present disclosure relates to the technical field of batteries, and in particular to a winding core structure and a battery. Background Art

[0002] During the cycle of lithium-ion batteries, lithium is deintercalated during charge and discharge of the positive and negative electrodes, resulting in the gradual deterioration of the bonding effect between the active material and the current collector, and between the electrode and the diaphragm, causing the gap inside the core to gradually increase. In high-energy-density system batteries, the compaction density of the positive and negative electrodes is high, the porosity of the electrode is low, and the storage of electrolyte inside the battery is limited. The electrolyte, as a transmission medium, is continuously consumed during the cycle. The combination of the increase in the core gap and the consumption of the electrolyte results in the electrolyte being unable to 100% cover the electrode in the later stages of the battery cycle, resulting in the inability to properly intercalate lithium on the negative electrode side.

[0003] However, since there are folds on both sides of the core, the expansion coefficients of the positive and negative electrodes on both sides of the core are inconsistent, resulting in a large gap between the two sides of the core, that is, a large gap at the fold of the core. Due to the large gap at the fold of the core, it is difficult for the electrolyte to completely cover the electrode at the fold of the core, causing the electrode at the fold of the core to be more prone to black spots and lithium precipitation, which reduces the battery cycle retention rate and shortens the battery life. Utility Model Content

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a roll core structure and a battery that can suppress the formation of black spots and lithium at the folds.

[0005] The purpose of this disclosure is achieved through the following technical solutions:

[0006] A winding core structure comprises a positive electrode sheet, a separator and a negative electrode sheet, wherein the positive electrode sheet, the separator and the negative electrode sheet are wound together to form a winding core, wherein the separator is located between the positive electrode sheet and the negative electrode sheet, wherein two unfolding planes and two bending planes are formed on the outer side surface of the winding core, wherein the two unfolding planes are respectively a first unfolding plane and a second unfolding plane, wherein the two bending planes are respectively a first bending plane and a second bending plane, wherein the first unfolding plane, the first bending plane, the second unfolding plane and the second bending plane are respectively connected end to end, wherein the winding core structure further comprises a binding colloid, wherein the binding colloid is respectively adhered to the two bending surfaces, wherein the binding colloid completely covers each bending surface, and wherein the length of the binding colloid is greater than or equal to the width of the positive electrode sheet.

[0007] In one embodiment, the binding colloid includes two binding tapes, and the two binding tapes are respectively attached to the two bending surfaces.

[0008] In one embodiment, both side edges of each of the binding tapes are also attached to the two unfolding planes.

[0009] In one embodiment, each of the binding tapes includes an arc portion and a plane portion, the two plane portions of each of the binding tapes are respectively connected to the two side edges of the corresponding arc portion, the two plane portions of each of the binding tapes are respectively adhered to the two unfolded planes, and the arc portion of each of the binding tapes is adhered to the corresponding bending surface.

[0010] In one embodiment, the two planar portions of each binding tape are symmetrically arranged.

[0011] In one embodiment, the two binding tapes are symmetrically arranged.

[0012] In one embodiment, the length of the bound colloid is equal to the width of the positive electrode sheet.

[0013] In one embodiment, the bound colloid has a thickness of 10 μm to 16 μm.

[0014] In one embodiment, the bound colloid has a thickness of 12 μm.

[0015] A battery comprises the winding core structure described in any one of the above embodiments.

[0016] Compared with the prior art, the present invention has at least the following advantages:

[0017] In the above-mentioned winding core structure, the binding colloid is respectively adhered to the two bending surfaces, the binding colloid completely covers each bending surface, and the length of the binding colloid is greater than or equal to the width of the positive electrode sheet, so that the binding colloid holds the bending surface of the winding core structure, that is, the binding colloid holds the crease of the winding core, which plays a role in suppressing the deformation of the crease of the winding core, suppressing the problem of increase in the gap at the crease of the winding core, and further suppressing the problem of black spots and lithium precipitation at the crease of the winding core, thereby improving the battery cycle retention rate and extending the battery life. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is a schematic structural diagram of a winding core structure according to an embodiment;

[0020] Figure 2 for Figure 1 Another structural schematic diagram of the winding core structure shown;

[0021] Figure 3 for Figure 1 Another structural schematic diagram of the winding core structure shown;

[0022] Figure 4 for Figure 1 A structural cross-sectional view of a winding core structure shown.

[0023] Reference numerals: winding core structure 10 ; winding core 10 a ; positive electrode sheet 100 ; separator 200 ; negative electrode sheet 300 ; unfolded plane 101 ; first unfolded plane 1011 ; second unfolded plane 1012 ; bending surface 102 ; first bending surface 1021 ; second bending surface 1022 ; restraining colloid 400 ; restraining tape 410 ; arc portion 411 ; plane portion 412 . DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of the present disclosure, the present disclosure will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present disclosure are given in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present disclosure more thoroughly and comprehensively understood.

[0025] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present disclosure. The terms used herein in the specification of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0027] In order to better understand the technical solutions and beneficial effects of the present invention, the present invention is further described in detail below in conjunction with specific embodiments:

[0028] like Figures 1 to 4As shown, a winding core structure 10 of an embodiment includes a positive electrode sheet 100, a separator 200 and a negative electrode sheet 300. The positive electrode sheet 100, the separator 200 and the negative electrode sheet 300 are wound together to form a winding core 10a. The separator 200 is located between the positive electrode sheet 100 and the negative electrode sheet 300. Two unfolding planes 101 and two bending surfaces 102 are formed on the outer side surface of the winding core 10a. The two unfolding planes 101 are respectively a first unfolding plane 1011 and a second unfolding plane 1012. The two bending surfaces 102 are respectively a first bending surface 1021 and a second bending surface 1022. The first unfolding plane 1011, the first bending surface 1021, the second unfolding plane 1012 and the second bending surface 1022 are respectively connected end to end. The winding core structure 10 further includes a binding colloid 400 , which is respectively attached to the two bending surfaces 102 , and the binding colloid 400 completely covers each bending surface 102 . The length of the binding colloid 400 is greater than or equal to the width of the positive electrode sheet 100 , and the binding colloid 400 covers all parts of each bending surface 102 .

[0029] like Figure 3 and Figure 4 As shown, in this embodiment, the bending surface 102 is the fold of the winding core 10a, and the unfolded plane 101 is a flat structure. It should be noted that due to problems such as winding accuracy, accidental extrusion, accidental bending, etc., the unfolded plane 101 may become a slightly curved surface, a plane with pits, or a curved surface with pits, but it is still within the protection scope of the present invention.

[0030] In the above-mentioned winding core structure 10, the binding colloid 400 is respectively attached to the two bending surfaces 102, and the binding colloid 400 completely covers each bending surface 102. The length of the binding colloid 400 is greater than or equal to the width of the positive electrode sheet 100, so that the binding colloid 400 clamps the bending surface 102 of the winding core structure 10, that is, the binding colloid 400 clamps the fold of the winding core 10a, which plays a role in suppressing the deformation of the fold of the winding core 10a, suppressing the problem of increase in the gap at the fold of the winding core 10a, and further suppressing the problem of black spot lithium precipitation at the fold of the winding core 10a, thereby improving the battery cycle retention rate and extending the battery life.

[0031] like Figure 3 As shown, in one embodiment, the binding colloid 400 includes two binding tapes 410, and the two binding tapes 410 are respectively attached to the two bending surfaces 102. In this embodiment, the two binding tapes 410 respectively bind the two bending surfaces 102, that is, the two binding tapes 410 respectively bind the two folds, which prevents the binding colloid 400 from acting on other areas and saves the material of the binding colloid 400.

[0032] like Figure 3As shown, in one of the embodiments, the two side edges of each binding tape 410 are also attached to the two unfolding planes 101, which increases the contact area between the binding tape 410 and the winding core 10a, improves the position stability of the binding tape 410, and further improves the effect of the binding tape 410 in suppressing deformation at the crease.

[0033] like Figure 3 As shown, in one embodiment, each binding tape 410 includes an arc portion 411 and a plane portion 412, and the two plane portions 412 of each binding tape 410 are respectively connected to the two sides of the corresponding arc portion 411, and the two plane portions 412 of each binding tape 410 are respectively attached to the two unfolded planes 101, and the arc portion 411 of each binding tape 410 is attached to the corresponding bending surface 102. In this embodiment, the arc surface is attached to the arc surface, and the plane portion 412 is attached to the unfolded plane 101, which increases the contact area between the binding tape 410 and the winding core 10a, improves the position stability of the binding tape 410, and further improves the effect of the binding tape 410 in suppressing deformation at the fold.

[0034] like Figures 1 to 3 As shown, in one embodiment, the two plane portions 412 of each binding tape 410 are symmetrically arranged, so that the binding force on the winding core 10a is more uniform, thereby improving the shape stability of the winding core 10a.

[0035] like Figures 1 to 3 As shown, in one embodiment, two binding tapes 410 are symmetrically arranged, so that the binding force on the winding core 10a is more uniform, thereby improving the shape stability of the winding core 10a.

[0036] like Figure 1 and Figure 2 As shown, in one embodiment, the length of the binding colloid 400 is equal to the width of the positive electrode sheet 100 , so that the binding colloid 400 can completely cover the fold and save the material of the binding colloid 400 .

[0037] In one embodiment, the thickness of the binding colloid 400 is 10 μm to 16 μm, so that the binding effect of the binding colloid 400 is better.

[0038] In one embodiment, the thickness of the binding colloid 400 is 12 μm. In another embodiment, the thickness of the binding colloid 400 is 10 μm. In yet another embodiment, the thickness of the binding colloid 400 is 16 μm.

[0039] The present disclosure further provides a battery, comprising the winding core structure 10 described in any one of the above embodiments, the battery further comprising an outer shell, and the winding core structure 10 is disposed in the outer shell.

[0040] Compared with the prior art, the present invention has at least the following advantages:

[0041] In the above-mentioned winding core structure 10, the binding colloid 400 is respectively attached to the two bending surfaces 102, and the binding colloid 400 completely covers each bending surface 102. The length of the binding colloid 400 is greater than or equal to the width of the positive electrode sheet 100, so that the binding colloid 400 clamps the bending surface 102 of the winding core structure 10, that is, the binding colloid 400 clamps the fold of the winding core 10a, which plays a role in suppressing the deformation of the fold of the winding core 10a, suppressing the problem of increase in the gap at the fold of the winding core 10a, and further suppressing the problem of black spot lithium precipitation at the fold of the winding core 10a, thereby improving the battery cycle retention rate and extending the battery life.

[0042] The above-mentioned embodiments only express several implementation methods of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the disclosed patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the disclosed patent shall be subject to the attached claims.

Claims

1. A winding core structure, comprising a positive electrode sheet, a separator and a negative electrode sheet, wherein the positive electrode sheet, the separator and the negative electrode sheet are wound together to form a winding core, wherein the separator is located between the positive electrode sheet and the negative electrode sheet, wherein the outer side surface of the winding core is formed with two unfolding planes and two bending surfaces, wherein the two unfolding planes are respectively a first unfolding plane and a second unfolding plane, wherein the two bending surfaces are respectively a first bending surface and a second bending surface, wherein the first unfolding plane, the first bending surface, the second unfolding plane and the second bending surface are connected end to end in sequence, wherein: The winding core structure further includes a binding colloid, which is respectively attached to the two bending surfaces, and the binding colloid completely covers each bending surface. The length of the binding colloid is greater than or equal to the width of the positive electrode sheet.

2. The winding core structure according to claim 1, characterized in that: The binding colloid comprises two binding tapes, and the two binding tapes are respectively attached to the two bending surfaces.

3. The winding core structure according to claim 2, characterized in that: Both side edges of each of the binding tapes are also attached to the two unfolding planes.

4. The winding core structure according to claim 3, characterized in that: Each of the binding tapes includes an arc portion and a plane portion, the two plane portions of each of the binding tapes are respectively connected to the two side edges of the corresponding arc portion, the two plane portions of each of the binding tapes are respectively adhered to the two unfolded planes, and the arc portion of each of the binding tapes is adhered to the corresponding bending surface.

5. The winding core structure according to claim 4, characterized in that: The two plane parts of each binding tape are symmetrically arranged.

6. The winding core structure according to claim 2, characterized in that: The two binding tapes are symmetrically arranged.

7. The winding core structure according to claim 1, characterized in that: The length of the bound colloid is equal to the width of the positive electrode sheet.

8. The winding core structure according to claim 1, characterized in that: The bound colloid has a thickness of 10 μm to 16 μm.

9. The winding core structure according to claim 8, characterized in that: The thickness of the bound colloid is 12 μm.

10. A battery, characterized in that: The invention comprises the winding core structure according to any one of claims 1 to 9.

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