CN214956956U - Roll core, battery pack and terminal - Google Patents

Roll core, battery pack and terminal Download PDF

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Publication number
CN214956956U
CN214956956U CN202121375023.2U CN202121375023U CN214956956U CN 214956956 U CN214956956 U CN 214956956U CN 202121375023 U CN202121375023 U CN 202121375023U CN 214956956 U CN214956956 U CN 214956956U
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layer
positive electrode
active layer
electrode active
pole piece
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包政海
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Beijing Xiaomi Mobile Software Co Ltd
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Beijing Xiaomi Mobile Software Co Ltd
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50Manufacturing or production processes characterised by the final manufactured product

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Abstract

The utility model provides a roll up core, battery package and terminal, roll up the core and include: the winding core comprises a positive pole piece, a negative pole piece and a diaphragm which are distributed in a stacked mode, wherein the positive pole piece, the negative pole piece and the diaphragm are wound together to form the winding core; the negative pole piece includes: the negative electrode base layer and the negative electrode active layer are positioned on the surface of the negative electrode base layer; the positive pole piece includes: the cathode comprises a cathode base layer, a cathode active layer and a filling layer, wherein the cathode active layer and the filling layer are positioned on the surface of the cathode base layer; the filling layers are positioned on the surface of the positive electrode base layer at the two ends of the positive electrode active layer, the end part far away from the positive electrode active layer is flush with the end part of the negative electrode active layer, and the filling layers are filled in the gap between the positive electrode base layer and the diaphragm; the separator is located between the positive electrode active layer and the negative electrode active layer. The technical scheme of the embodiment of the disclosure improves the cycle efficiency and the safety of the battery pack and prolongs the service life of the battery pack.

Description

Roll core, battery pack and terminal
Technical Field
The disclosure relates to the technical field of batteries, in particular to a winding core, a battery pack and a terminal.
Background
With the popularization of clean energy technology in various fields, the battery technology is paid unprecedented attention and is widely applied. At present, due to the limitations of various aspects such as performance, structure, process, safety, cost and the like, a battery pack is increasingly difficult to meet the requirements of consumers on the aspects such as long service life of terminal products. Therefore, the development of long-life and safe battery packs has become an important direction of research in the industry.
In order to ensure the safety of the winding core in the battery pack, during winding, at the starting position and the ending position of the winding, an active material layer on the positive pole piece and an active material layer on the negative pole piece are not aligned, and the part of the negative pole piece, which exceeds the positive pole piece, is called an extending part (overlap). The protruding part is easy to aggravate the expansion of the battery pack, so that the attenuation of the battery capacity is accelerated, and the service life of the battery pack is shortened.
SUMMERY OF THE UTILITY MODEL
The present disclosure provides a winding core, a battery pack, and a terminal.
According to an embodiment of a first aspect of the present disclosure, there is provided a winding core, including: the winding core comprises a positive pole piece, a negative pole piece and a diaphragm which are distributed in a stacked mode, wherein the positive pole piece, the negative pole piece and the diaphragm are wound together to form the winding core;
the negative pole piece includes: the negative electrode base layer and the negative electrode active layer are positioned on the surface of the negative electrode base layer;
the positive pole piece includes: the cathode comprises a cathode base layer, a cathode active layer and a filling layer, wherein the cathode active layer and the filling layer are positioned on the surface of the cathode base layer; the filling layers are positioned on the surface of the positive electrode base layer at the two ends of the positive electrode active layer, the end part far away from the positive electrode active layer is flush with the end part of the negative electrode active layer, and the filling layers are filled in the gap between the positive electrode base layer and the diaphragm;
the separator is located between the positive electrode active layer and the negative electrode active layer.
In some embodiments, a difference between a thickness of the filling layer and a thickness of the cathode active layer is within a predetermined range.
In some embodiments, the positive electrode sheet further comprises:
and the insulating protective layer covers the filling layer and the positive electrode base layer respectively.
In some embodiments, a difference between a total thickness of the protective layer and the filling layer covered on the filling layer and a thickness of the positive electrode active layer is within a preset range.
In some embodiments, the protective layer comprises a pressure sensitive gel.
In some embodiments, the filler layer comprises a ceramic and/or gel.
In some embodiments, the positive electrode active layers are respectively located on a first surface and a second surface of the positive electrode base layer, wherein the first surface faces to the central position of the winding core, and the second surface is opposite to the first surface;
the filling layers are respectively positioned on the first surface and the second surface;
the length of the positive electrode active layer on the first surface is greater than or less than the length of the positive electrode active layer on the second surface.
In some embodiments, in the same winding layer, the negative electrode sheet is located between the positive electrode sheet and the central position of the winding core, and the length of the positive electrode active layer on the first surface is greater than that of the positive electrode active layer on the second surface; or the like, or, alternatively,
in the same winding layer, the positive pole piece is positioned between the negative pole piece and the center of the winding core, and the length of the positive active layer positioned on the second surface is greater than that of the positive active layer positioned on the first surface.
According to an embodiment of a second aspect of the present disclosure, there is provided a battery pack including:
an electrolyte;
the winding core of the embodiment of the first aspect is positioned in the electrolyte.
According to a third aspect of the present disclosure, there is provided a terminal, including:
a housing having a battery compartment;
the battery pack of the second aspect is mounted in the battery compartment.
The technical scheme provided by the embodiment of the disclosure can have the following beneficial effects:
according to the embodiment, the filling layer is introduced to the positive pole piece, the filling layer is used for filling the gap between the positive base layer and the diaphragm in the winding core, the consistency of the thickness of the winding core at the position of the filling layer and the position of the positive active layer is improved, and the uniformity of the thickness of the winding core at each position is improved. The improvement of the uniformity of the thickness is also beneficial to improving the compactness of the interface among the positive pole piece, the negative pole piece and the diaphragm, reducing the deformation of the winding core, relieving the expansion problem of the battery pack, slowing down the rate of decay of the capacity of the battery pack, improving the cycle efficiency and the safety of the battery pack and prolonging the service life of the battery pack.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure.
FIG. 1 is a schematic structural diagram of a positive electrode sheet;
FIG. 2 is a schematic structural view of a jellyroll including the positive electrode tab of FIG. 1;
FIG. 3 is a schematic diagram illustrating the structure of a positive pole piece according to an exemplary embodiment;
fig. 4 is a schematic structural view of a winding core including the positive electrode tab of fig. 3.
Detailed Description
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of devices consistent with certain aspects of the present disclosure, as detailed in the appended claims.
An embodiment of a first aspect of the present disclosure provides a winding core, including: the winding core comprises a positive pole piece 110, a negative pole piece 120 and a diaphragm 130 which are distributed in a stacked mode, wherein the positive pole piece 110, the negative pole piece 120 and the diaphragm 130 are wound together to form the winding core;
the negative electrode tab 120 includes: a negative electrode base layer 121 and a negative electrode active layer 122 on the surface of the negative electrode base layer 121;
the positive electrode tab 110 includes: a positive electrode base layer 111, a positive electrode active layer 112 and a filling layer 114 on the surface of the positive electrode base layer 111; the filling layer 114 is positioned on the surface of the positive electrode base layer 111 at two ends of the positive electrode active layer 112, and the end of the filling layer 114 far away from the positive electrode active layer 112 is flush with the end of the negative electrode active layer 122, and the filling layer 114 is filled in the gap between the positive electrode base layer 111 and the separator 130;
the separator 130 is located between the positive electrode active layer 112 and the negative electrode active layer 122.
The winding core and the battery pack take a lithium ion battery pack as an example. During charging of the battery pack, lithium ions are extracted from the positive active layer and inserted into the negative active layer. If the lithium ions can not be inserted into the negative pole piece, the lithium ions can be separated out on the surface of the negative pole piece in the form of lithium simple substances, and finally lithium dendrites are formed. Lithium dendrites tend to pierce the separator of the jelly roll, causing internal short circuits in the battery pack. To alleviate this problem, the negative active layer on the negative electrode tab needs to be in excess. In the example shown in fig. 1 and 2, in the negative electrode sheet 20 of the winding core, the length of the negative electrode active layer 21 is greater than the length of the positive electrode active layer 11 in the positive electrode sheet 10, and an overhang (overlap) 30 is formed. Since the separator 50 is provided between the positive electrode active layer 11 and the negative electrode active layer 21, if a filler layer is not provided at the position of the protruding portion 30, the protruding portion 30 may be opposed to the positive electrode base layer 13 with the gap 40 between the positive electrode base layer 13 and the separator 50. This gap 40 can cause the pole pieces to deform, thereby exacerbating the battery pack swelling.
As shown in fig. 4, the embodiment of the present disclosure improves the consistency of the thickness of the jelly roll at the position of the filling layer 114 and the position of the positive active layer 112 by introducing the filling layer 114 on the positive electrode tab 110 and filling the gap between the positive base layer 111 and the separator 130 in the jelly roll with the filling layer 114, thereby improving the uniformity of the thickness of the jelly roll at each position. The improvement of the uniformity of the thickness is also beneficial to improving the compactness of the interface among the positive pole piece 110, the negative pole piece 120 and the diaphragm 130, enhancing the cohesiveness of the binding core when all layers are attached, reducing the deformation of the binding core, relieving the expansion problem of the battery pack, slowing down the rate of decay of the battery capacity, improving the cycle efficiency and the safety of the battery pack and prolonging the service life of the battery pack.
The end of the filling layer 114 far from the positive electrode active layer 112 is flush with the end of the negative electrode active layer 122, which means that the difference between the sum of the lengths of the positive electrode active layer 112 and the filling layer 114 and the length of the negative electrode active layer 122 along the length direction of the pole piece (including the positive electrode pole piece 110 and/or the negative electrode pole piece 120) is within a preset range. The predetermined range is generally 0 or close to 0.
The filling layer 114 does not affect the internal environment of the battery pack. For example: the filling layer 114 does not affect the formation of lithium ions in the battery pack, does not react with the electrolyte in the battery pack, and the like.
In some embodiments, the filler layer 114 includes a ceramic and/or gel. For example, the filler layer 114 may be a layer of ceramic material, or a layer of colloidal material, or a mixed coating of ceramic material and colloidal material. The colloidal material includes, but is not limited to, acrylic colloidal materials. It is understood that other materials may be selected for the fill layer 114.
The filling layer 114 may be a coating layer, and the filling layer 114 includes a powdery raw material, and the filling layer 114 may be formed by coating. The filling layer 114 including the powdery raw material is more suitable for filling the gap 40 having a small space size, and the effect of filling the gap 40 can be further improved, thereby further improving the uniformity of the thickness between the layers of the core.
The filling layer 114 may be a solid adhesive, and the filling layer 114 may be formed by bonding a sheet-shaped solid adhesive tape to the positive electrode base layer 111.
For a lithium battery, the positive active layer 112 on the positive electrode sheet 110 includes a positive active material capable of absorbing and releasing lithium ions, and the positive active material includes, but is not limited to, one or a combination of more of lithium cobaltate, lithium iron phosphate, lithium nickel cobalt manganese oxide, lithium manganate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadyl phosphate, lithium iron phosphate, or lithium titanate.
The negative active layer 122 on the negative electrode sheet 120 includes a negative active material capable of absorbing and releasing lithium ions, and the negative active material includes, but is not limited to, a transition metal oxide NaxMO2(M is a transition metal, such as one or more of Mn, Fe, Ni, Co, V, Cu, Cr, 0<x is less than or equal to 1) or polyanionic materials (phosphate, fluorophosphate, pyrophosphate, sulfate) and the like.
The positive electrode base layer 111 may be selected from aluminum foil or nickel foil. Of course, other materials may be used as the positive electrode base layer 111.
The negative electrode substrate 121 may be a copper foil or a nickel foil. Of course, other materials may also be employed as the negative electrode base layer 121.
Generally, the membrane 130 is a porous structure for ions to pass through. The membrane 130 includes, but is not limited to, a combination of one or more of a polyolefin, a polyamide, a polyimide, a polyester, or an aramid.
In some embodiments, the winding core further comprises: the positive electrode tab 140 is connected with the positive electrode pole piece 110, and the negative electrode tab 150 is connected with the negative electrode pole piece 120.
The lug is used for realizing the output of current to the outside of the battery pack or transmitting the current outside the battery pack into the battery pack.
Taking the positive electrode tab 140 as an example, the positive electrode tab 140 may be located on one side of the positive electrode active layer 112 and spaced apart from an end of the positive electrode active layer 112, or the positive electrode tab 140 may be located in a middle position of the positive electrode active layer 112 region. The number of the tabs on the positive pole piece 110 may be one or more, so as to form a multi-tab. Fig. 4 exemplarily shows that the positive electrode tab 140 may be located at one side of the positive electrode active layer 112, and the positive electrode tab 140 may be welded on the positive electrode base layer 111. The distribution of the negative electrode tab 150 is similar to that of the positive electrode tab 140, and a description thereof will not be repeated.
The number of membranes 130 in the jellyroll is typically two or more.
Fig. 4 exemplarily shows a jellyroll comprising two membranes 130. In practical application, after the separator 130, the negative electrode tab 120, the separator 130 and the positive electrode tab 110 are sequentially stacked to form a stacked assembly, one end of the stacked assembly is fixed on a winding needle, and then the stacked assembly is wound along the axis of the winding needle to form a winding core.
In other alternative embodiments, the difference between the thickness of the filling layer 114 and the thickness of the positive active layer 112 is within a predetermined range.
The predetermined range is generally 0 or close to 0.
In some embodiments, the thickness of the filler layer 114 is approximately equal to the thickness of the positive active layer 112.
For the positive pole piece 110, the thickness of the filling layer 114 is approximately equal to that of the positive active layer 112, so that the flatness of the coating on the surface of the positive base layer 111 is improved. In the process of winding the negative pole piece 120 and the diaphragm 130 to form the battery core, the tightness of the lamination of each layer of the winding core is further ensured, the uniformity of stress of each layer of the winding core is improved in the thickness hot pressing forming process of the battery pack, the risk of pole piece deformation caused by black spot lithium precipitation in the circulating process is reduced, and the safety is improved; meanwhile, the cycle capacity attenuation is slowed down, and the service life of the lithium ion battery is prolonged.
In some other optional embodiments, the positive electrode sheet 110 further includes:
and an insulating protective layer 115 covering the filling layer 114 and the positive electrode base layer 111, respectively.
As shown in fig. 3, the protection layer 115 is located at the boundary position between the positive electrode active layer 112 and the positive electrode base layer 111, and has a protection effect on the positive electrode active layer 112. In addition, the protective layers 115 are disposed at both ends of the positive electrode active layer 112, and provide positioning information to mechanical equipment such as winding equipment during the production of the battery pack, thereby having a terminating function.
In other alternative embodiments, the protective layer 115 includes a pressure sensitive gel.
Without limitation, the pressure sensitive adhesive includes an insulating substrate including, but not limited to, polypropylene or polyvinyl chloride, and an adhesive on a surface of the insulating substrate. The adhesive may be an acrylic adhesive.
To enhance the terminating action of the protective layer 115, the protective layer 115 generally has a color, for example: yellow, blue or green, etc.
Without limitation, the protective layer 115 may not be provided, and the positive electrode active layer 112 may be protected by the filling layer 114 instead of the protective layer 115. For example, when the filling layer 114 is an insulating solid glue, the filling layer 114 may replace the protective layer 115.
In some embodiments, the filling layer 114 has an insulating property, and the filling layer 114 is located at two ends of the positive electrode active layer 112 and covers the positive electrode active layer 112 and the positive electrode base layer 111 respectively, wherein the thickness of the filling layer 114 located on the positive electrode base layer 111 is substantially equal to the thickness of the positive electrode active layer 112, and the thickness of the filling layer 114 located on the positive electrode active layer 112 is smaller than the thickness of the positive electrode active layer 112, so as to ensure the flatness of the surface of the positive electrode sheet 110.
The insulating filler layer 114 can further improve the insulating protection of the end portion of the positive electrode active layer 112, reduce the leakage of the battery pack, and improve the safety of the battery pack.
It is understood that the filling layer 114 may also be a non-insulating layer, such as: the filler layer 114 includes carbon black, carbon nanotubes, or the like.
In other alternative embodiments, the difference between the total thickness of the protective layer 115 and the filler layer 114 covering the filler layer 114 and the thickness of the positive active layer 112 is within a predetermined range.
The predetermined range is generally 0 or close to 0. As shown in fig. 3, the sum of the thickness of the partial protective layer 115 covering the filler layer 114 and the thickness of the filler layer 114 is substantially equal to the thickness of the positive electrode active layer 112. This structure reduces unevenness of the positive electrode sheet 110 caused by the introduction of the protective layer 115, and further improves the tightness of the jelly roll in the thickness direction.
In other alternative embodiments, the positive electrode active layer 112 is respectively disposed on a first surface and a second surface of the positive electrode base layer 111, wherein the first surface faces the central position of the winding core, and the second surface is opposite to the first surface;
the filling layer 114 is respectively positioned on the first surface and the second surface;
the length of the positive electrode active layer 112 on the first surface is greater or less than the length of the positive electrode active layer 112 on the second surface.
As shown in fig. 3, the lengths of the positive electrode active layers 112 on both surfaces of the positive electrode base layer 111 are not equal, and this structure is advantageous to fully utilize all the positive electrode active layers 112 on the positive electrode base layer 111, and to reduce the waste of the positive electrode active layers 112 at the start position or the end position of winding. As shown in fig. 4, since the length of the positive electrode active layer 112 on the first surface is greater than the length of the positive electrode active layer 112 on the second surface, when the positive electrode tab 110 is located at the outermost side, the second surface of the positive electrode substrate at the end position of the winding core will not participate in the reaction, and the positive electrode active layer 112 is not disposed here, belonging to the empty foil region, thereby reducing the waste of the positive electrode active layer 112.
In some embodiments, the length of the negative electrode active layer 122 of the negative electrode base layer 121 facing the second surface is less than the length of the negative electrode active layer 122 of the negative electrode base layer 121 facing the first surface. Similar to the structure of the positive electrode tab 110, this structure is advantageous to fully utilize all the negative active layers 122 on the negative base layer 121, and reduce the waste of the negative active layers 122 at the start position or the end position of winding.
In other optional embodiments, in the same winding layer, the negative electrode sheet 120 is located between the positive electrode sheet 110 and the central position of the winding core, and the length of the positive electrode active layer 112 on the first surface is greater than the length of the positive electrode active layer 112 on the second surface; or the like, or, alternatively,
in the same winding layer, the positive electrode sheet 110 is located between the negative electrode sheet 120 and the center of the winding core, and the length of the positive electrode active layer 112 on the second surface is greater than that of the positive electrode active layer 112 on the first surface.
In the winding process of the stacked positive electrode tab 110 and the negative electrode tab 120, the positive electrode tab 110 may be located on the outer side, and the negative electrode tab 120 may be located on the inner side, as shown in fig. 4, at this time, the negative electrode tab 120 is located between the positive electrode tab 110 and the center of the winding core. Alternatively, the positive electrode sheet 110 may be located on the inside and the positive electrode sheet 110 on the outside.
An embodiment of a second aspect of the present disclosure provides a battery pack, including:
an electrolyte;
the winding core of the embodiment of the first aspect is positioned in the electrolyte.
During the charging and discharging process of the battery pack, the electrolyte is used for realizing the transmission of lithium ions, so that the lithium ions are exchanged between the positive pole piece 110 and the negative pole piece 120.
Generally, the electrolyte includes a solvent, and a lithium salt dispersed and dissolved in the solvent. Further, lithium salts include, but are not limited to LiPF6、LiBF4、LiAsF6、LiClO4、LiB(C6H5)4、LiCH3SO3、LiCF3SO3、LiN(SO2CF3)2、LiC(SO2CF3)3Or LiSiF6One or more of the above. The solvent includes, but is not limited to, a combination of one or more of carbonate compounds, carboxylate compounds, ether compounds, or other organic solvents. For example: ethylene carbonate, propylene carbonate, dimethyl sulfoxide, N-methyl-2-pyrrolidone, formamide or dimethylformamide.
An embodiment of a third aspect of the present disclosure provides a terminal, where the terminal includes:
a housing having a battery compartment;
the battery pack of the second aspect is mounted in the battery compartment.
Terminals include, but are not limited to, laptops, desktops, tablets, electronic book players, cell phones, televisions, calculators, backup power supplies, automobiles, motorcycles, mopeds, lighting fixtures, wearable devices, game consoles, clocks, power tools, or cameras, and the like.
In a specific example, as shown in fig. 3 and 4, filling layers 114 are added at the corresponding positions of the two ends of the positive electrode active layer 112 in the length direction, and the filling layers 114 may be ceramic coatings, glue layers, and the like, including but not limited to these substances; the filling layer 114 does not participate in the internal reaction of the battery, does not affect the internal environment of the battery, and the like, and the thickness of the positive electrode active layer 112 on the positive electrode base layer 111 is consistent with that of the filling layer 114. At the winding core starting position, the end faces of the filler layers 114 on both surfaces of the positive electrode base layer 111 are aligned with the corresponding end faces of the negative electrode active layer 122 on the negative electrode base layer 121. At the ending position, the end faces of the negative electrode active layers 122 on the negative electrode base layer 121 are aligned with the end faces of the filling layers 114 on the two surfaces of the corresponding positive electrode base layer 111; thus, the layers of the winding core are closely integrated in the thickness direction.
Features disclosed in several of the product embodiments provided in this disclosure may be combined in any combination to yield new product embodiments without conflict.
Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.
It will be understood that the present disclosure is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims (10)

1. A winding core, characterized in that it comprises: the winding core comprises a positive pole piece, a negative pole piece and a diaphragm which are distributed in a stacked mode, wherein the positive pole piece, the negative pole piece and the diaphragm are wound together to form the winding core;
the negative pole piece includes: the negative electrode base layer and the negative electrode active layer are positioned on the surface of the negative electrode base layer;
the positive pole piece includes: the cathode comprises a cathode base layer, a cathode active layer and a filling layer, wherein the cathode active layer and the filling layer are positioned on the surface of the cathode base layer; the filling layers are positioned on the surface of the positive electrode base layer at the two ends of the positive electrode active layer, the end part far away from the positive electrode active layer is flush with the end part of the negative electrode active layer, and the filling layers are filled in the gap between the positive electrode base layer and the diaphragm;
the separator is located between the positive electrode active layer and the negative electrode active layer.
2. The winding core according to claim 1, wherein a difference between a thickness of the filler layer and a thickness of the positive electrode active layer is within a predetermined range.
3. The winding core of claim 1, wherein the positive pole piece further comprises:
and the insulating protective layer covers the filling layer and the positive electrode base layer respectively.
4. The winding core according to claim 3, wherein the difference between the total thickness of the protective layer and the filling layer covered on the filling layer and the thickness of the positive electrode active layer is within a preset range.
5. The winding core of claim 3, wherein the protective layer comprises a pressure sensitive gel.
6. The winding core of claim 1, wherein the filler layer comprises a ceramic and/or gel.
7. The winding core according to claim 1, wherein the positive electrode active layer is respectively disposed on a first surface and a second surface of the positive electrode base layer, wherein the first surface faces a central position of the winding core, and the second surface is opposite to the first surface;
the filling layers are respectively positioned on the first surface and the second surface;
the length of the positive electrode active layer on the first surface is greater than or less than the length of the positive electrode active layer on the second surface.
8. The winding core according to claim 7, wherein in the same winding layer, the negative electrode sheet is positioned between the positive electrode sheet and the center position of the winding core, and the length of the positive electrode active layer on the first surface is longer than that of the positive electrode active layer on the second surface; or the like, or, alternatively,
in the same winding layer, the positive pole piece is positioned between the negative pole piece and the center of the winding core, and the length of the positive active layer positioned on the second surface is greater than that of the positive active layer positioned on the first surface.
9. A battery pack, comprising:
an electrolyte;
the winding core of any of claims 1 to 8, being located in the electrolyte.
10. A terminal, characterized in that the terminal comprises:
a housing having a battery compartment;
the battery pack of claim 9 mounted within the battery compartment.
CN202121375023.2U 2021-06-21 2021-06-21 Roll core, battery pack and terminal Active CN214956956U (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024083167A1 (en) * 2022-10-18 2024-04-25 珠海冠宇动力电池有限公司 Battery

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024083167A1 (en) * 2022-10-18 2024-04-25 珠海冠宇动力电池有限公司 Battery

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