CN112928340A - Roll up core structure and lithium ion battery - Google Patents
Roll up core structure and lithium ion battery Download PDFInfo
- Publication number
- CN112928340A CN112928340A CN202110334030.6A CN202110334030A CN112928340A CN 112928340 A CN112928340 A CN 112928340A CN 202110334030 A CN202110334030 A CN 202110334030A CN 112928340 A CN112928340 A CN 112928340A
- Authority
- CN
- China
- Prior art keywords
- core structure
- tab
- positive
- negative
- winding
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
- H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
-
- Y—GENERAL 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
-
- Y—GENERAL 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Secondary Cells (AREA)
Abstract
The application provides a roll up core structure and lithium ion battery. The winding core structure comprises a positive electrode assembly, a negative electrode assembly, a diaphragm and a leveling piece, wherein the positive electrode assembly, the diaphragm and the negative electrode assembly are sequentially stacked and wound together, and both the positive electrode assembly and the negative electrode assembly comprise a pole piece and a pole lug; the positive component comprises a positive plate and a positive tab, and the negative component comprises a negative plate and a negative tab; at least one of the positive plate or the negative plate is provided with a leveling piece in the surrounding area of the pole ear, the leveling piece is in contact with the pole ear, and the thickness of the leveling piece is larger than or equal to that of the pole ear. The application provides a roll up core structure's surface smoothness is better.
Description
Technical Field
The application relates to the technical field of lithium ion batteries, in particular to a roll core structure and a lithium ion battery.
Background
A lithium ion battery is a secondary battery (rechargeable battery) which mainly depends on the movement of lithium ions between a positive electrode and a negative electrode, and the energy density, the quick charging capability, the charge-discharge rate and the like of the lithium ion battery affect the service performance of the lithium ion battery. However, whether the flatness of the battery core is good or not affects the long cycle life of the lithium ion battery and the expansion problem of the lithium ion battery in the cycle process, and even affects whether the lithium ion battery is deformed in the use process.
However, in the conventional lithium ion battery, due to the existence of the tab, the surface flatness of the winding core structure is poor.
Disclosure of Invention
The embodiment of the application provides a roll up core structure and lithium ion battery, wherein, roll up core structure's surface smoothness is better.
On one hand, the application provides a roll core structure, which comprises a positive electrode assembly, a negative electrode assembly, a diaphragm and a leveling member, wherein the positive electrode assembly, the diaphragm and the negative electrode assembly are sequentially stacked and wound together, and both the positive electrode assembly and the negative electrode assembly comprise a pole piece and a pole lug; the positive component comprises a positive plate and a positive tab, and the negative component comprises a negative plate and a negative tab; at least one of the positive plate or the negative plate is provided with a leveling piece in the surrounding area of the pole ear, the leveling piece is in contact with the pole ear, and the thickness of the leveling piece is larger than or equal to that of the pole ear.
Optionally, in the winding core structure provided by the application, the leveling member covers at least an area between the winding start end of the negative electrode sheet and an adjacent area of the winding start end of the positive electrode sheet in the radial direction of the winding core structure.
Optionally, in the winding core structure provided by the application, the maximum difference of the thickness of the leveling member at each position along the length direction of the pole piece is less than 10 μm.
Optionally, in the core structure that rolls up that this application provided, leveling piece is the adhesive tape, and the adhesive tape is filled the adhesive tape including filling adhesive tape and utmost point ear adhesive tape respectively in the region that lies in the length direction's of the pole piece both sides of utmost point ear, and utmost point ear adhesive tape covers utmost point ear and fills the adhesive tape.
Optionally, in the core structure that this application provided, the difference absolute value between the thickness of packing adhesive tape and the thickness of utmost point ear is 8 ~ 12 mu m.
Optionally, in the core structure provided by the application, the absolute value of the difference between the length of the tab gummed paper in the length direction of the pole piece and the sum of the lengths of the tab covered by the tab gummed paper and the filled gummed paper in the length direction is 0-3 mm.
Optionally, in the winding core structure provided by the present application, the pole piece includes a current collector and an active material, and the tab is welded to the current collector; the negative plate is provided with a single-side area with a single side coated with an active material at the core part of the winding core structure, and the single-side area is provided with a bending part.
Optionally, in the winding core structure provided by the application, the winding start end of the positive plate and the winding start end of the negative plate are arranged in a staggered manner, and the winding start end of the positive plate surrounds the winding start end of the negative plate; the positive plate has a step part at the core part of the winding core structure, and the leveling member extends from the winding starting end of the negative plate to the step part.
Optionally, in the winding core structure provided by the present application, the winding start end of the single-surface region, the winding start end of the active material of the positive electrode sheet, and the step portion are located at the same radial position of the winding core structure.
Optionally, in the winding core structure provided by the application, when the winding core structure is unfolded, an absolute value of a difference between a distance between the leveling member and the active material of the positive plate and twice the thickness of the tab is less than 1 mm.
Optionally, in the winding core structure provided by the application, at least part of the tab is welded on the tab to form a welding section of the tab, one end of the tab exceeds one axial side of the winding core structure, and the welding section of the tab at least extends to the other axial side of the tab along the winding core structure.
On the other hand, the application provides a lithium ion battery, including foretell book core structure to and, cladding book core structure's protection piece.
In the roll core structure and the lithium ion battery provided by the application, the roll core structure comprises a positive electrode component, a negative electrode component, a diaphragm and a leveling part, wherein the positive electrode component, the diaphragm and the negative electrode component are sequentially stacked and wound together, and both the positive electrode component and the negative electrode component comprise a pole piece and a pole lug; the positive component comprises a positive plate and a positive tab, and the negative component comprises a negative plate and a negative tab; at least one of the positive plate or the negative plate is provided with a leveling piece in the surrounding area of the pole ear, the leveling piece is in contact with the pole ear, and the thickness of the leveling piece is larger than or equal to that of the pole ear. The application provides a roll up core structure's surface smoothness is better.
The construction of the present application and other objects and advantages thereof will be more apparent from the following description of the preferred embodiments taken in conjunction with the accompanying drawings.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.
FIG. 1a is a schematic structural diagram of a conventional winding core structure;
FIG. 1b is a partial schematic view of a conventional winding core structure;
FIG. 1c is an enlarged view of a portion of a conventional core structure;
FIG. 1d is a schematic structural view of a negative electrode assembly in a conventional jelly roll structure;
fig. 1e is a schematic structural diagram of the cathode assembly in the conventional jelly roll structure after being unfolded;
FIG. 1f is a schematic structural diagram of a positive electrode assembly in a conventional jelly roll structure;
fig. 1g is a schematic structural diagram of a positive electrode assembly in a conventional roll core structure after being unfolded;
fig. 2a is a schematic structural diagram of a winding core structure provided in an embodiment of the present application;
fig. 2b is a partial structure schematic view of a core structure provided in an embodiment of the present application;
fig. 3a is a schematic structural diagram of a negative electrode assembly in a winding core structure provided by an embodiment of the present application;
fig. 3b is a schematic structural diagram of the unwound negative electrode assembly in the winding core structure according to the embodiment of the present application;
fig. 4a is a schematic structural diagram of a positive electrode assembly in a winding core structure provided by an embodiment of the present application;
fig. 4b is a schematic structural diagram of a unwound positive electrode assembly in the winding core structure according to the embodiment of the present application;
fig. 5a is a state diagram of an axial cutting of the winding core structure provided by the embodiment of the present application;
fig. 5b is a state diagram of radial cutting of the winding core structure provided by the embodiment of the application.
Description of reference numerals:
100. 200-a roll core structure; 1. 10-a positive electrode assembly; 11-positive plate; 111. 101-a positive current collector; 1111-a step portion; 112. 102-positive electrode active material; 12. 103-positive tab; 2. 20-a negative electrode assembly; 21-negative plate; 211. 201-negative current collector; 212. 202-negative active material; 2121-bending part; 22. 203-negative electrode tab; 3. 50-a membrane; 30-negative adhesive tape; 40-positive adhesive tape; 4-leveling member; 41-filling gummed paper; 41 a-positive electrode filling adhesive paper; 411 a-first positive electrode filling adhesive tape; 412 a-second positive filled gummed paper; 41 b-negative filling gummed paper; 411 b-first negative electrode filling adhesive tape; 412 b-second negative filled gummed paper; 42-tab gummed paper; 42 a-positive tab gummed paper; 421 a-first positive tab gummed paper; 422 a-second positive tab gummed paper; 42 b-negative tab gummed paper.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments.
All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application. The embodiments described below and the features of the embodiments can be combined with each other without conflict.
In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the present application.
In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
It should be noted that, in the description of the present application, the terms "first" and "second" are used merely for convenience in describing different components, and are not to be construed as indicating or implying a sequential relationship, relative importance, or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature.
A lithium ion battery is a secondary battery (rechargeable battery) which mainly depends on the movement of lithium ions between a positive electrode and a negative electrode, and the energy density, the quick charging capability, the charge-discharge rate and the like of the lithium ion battery affect the service performance of the lithium ion battery. During high-rate charging, if the interface of the lithium ion battery is not well bonded, the long cycle life of the lithium ion battery can be shortened, so that the lithium ion battery expands in the cycle process, and even the lithium ion battery deforms in the use process; the key to whether the interface bonding of the lithium ion battery is good is whether the pressure borne by the lithium ion battery in the formation process is uniform, and the key to whether the pressure borne by the lithium ion battery in the formation process is uniform is whether the flatness of the whole battery cell is good in the design process of the battery cell; if the flatness of the battery cell is poor, the pressure born by the pole piece is uneven in the formation process, and finally the battery cell has the problems of uneven surface, depression, wave deformation and the like. In the long circulation process, the stress borne by the battery cell in the circulation expansion process is uneven due to the flatness problem of the battery cell, and finally, the battery cell expands and deforms to cause capacity attenuation and expansion failure.
The conventional lithium ion battery comprises a roll core structure 100, an aluminum-plastic film (shell) wrapped outside the roll core structure 100, and electrolyte filled between the roll core structure 100 and the aluminum-plastic film (shell).
Fig. 1a is a schematic structural diagram of a conventional winding core structure. Fig. 1b is a partial schematic view of a conventional winding core structure. Fig. 1c is an enlarged view of a part of a conventional winding core structure. Fig. 1d is a schematic structural diagram of a negative electrode assembly in a conventional jelly roll structure. Fig. 1e is a schematic structural view of the cathode assembly after being unwound in the conventional winding core structure. Fig. 1f is a schematic structural diagram of a positive electrode assembly in a conventional winding core structure. Fig. 1g is a schematic structural diagram of a positive electrode assembly in a conventional roll core structure after being unfolded.
As shown in fig. 1a to 1g, the jelly roll structure 100 includes a positive electrode assembly 10, a negative electrode assembly 20, a gummed paper 30, and a separator 50; the positive electrode assembly 10 comprises a positive electrode current collector 101, a positive electrode active material 102 and a positive electrode tab 103, wherein the positive electrode current collector 101 and the positive electrode active material 102 form a positive electrode plate, the positive electrode tab 103 is welded on the positive electrode current collector 101, and the length of the welding section of the positive electrode tab 103 along the axial direction of the winding core structure 100 is smaller than the length of the positive electrode current collector 101 in the direction; the negative electrode assembly 20 comprises a negative electrode current collector 201, a negative electrode active substance 202 and a negative electrode tab 203, the negative electrode current collector 201 and the negative electrode active substance 202 form a negative electrode sheet, the negative electrode tab 203 is welded on the negative electrode current collector 201, and the length of the welding section of the negative electrode tab 203 along the axial direction of the roll core structure 100 is smaller than the length of the negative electrode current collector 201 in the direction; wherein, the winding starting end of the negative electrode active material 202 at the core part position of the winding core structure 100 and the winding starting end of the positive electrode active material 102 are at the same radial position of the winding core structure 100, and at the core part position of the winding core structure 100, the extension length of the negative electrode active material 202 in the radial direction of the winding core structure 100 is equal to the extension length of the positive electrode active material 102 in the direction; the separator 50 is disposed between the adjacent positive and negative electrode sheets; in order to prevent burrs generated in the welding process from piercing through the separator 50 to connect the positive electrode and the negative electrode, and to prevent the battery from short-circuiting, the negative electrode tab 203 and the welding surface of the negative electrode tab 203 and the negative electrode current collector 201 are covered with the negative electrode adhesive tape 30, and the positive electrode tab 103, the welding surface of the positive electrode tab 103 and the positive electrode current collector 101, and the back surface of the welding surface of the positive electrode tab 103 and the positive electrode current collector 101 are covered with the positive electrode adhesive tape 40.
Therefore, the surface flatness of the winding core structure 100 in the conventional lithium ion battery is poor, which can cause the problems of expansion and the like of the lithium ion battery in the circulation process, and shorten the cycle life of the lithium ion battery.
Therefore, the embodiment of the application provides a roll core structure and a lithium ion battery, which can prevent the lithium ion battery from swelling and the like in the circulation process.
Fig. 2a is a schematic structural diagram of a core structure provided in an embodiment of the present application. Fig. 2b is a partial structure schematic diagram of a core structure provided in the embodiment of the present application.
As shown in fig. 2a and fig. 2b, the present embodiment provides a winding core structure 200, including positive electrode assembly 1, negative electrode assembly 2 and diaphragm 3, positive electrode assembly 1, diaphragm 3 and negative electrode assembly 2 are stacked up in proper order and coiled together jointly, positive electrode assembly 1 and negative electrode assembly 2 include pole piece and utmost point ear respectively, the welding section of at least part welding in order to form utmost point ear on the pole piece of utmost point ear, the one end of utmost point ear surpasss the axial one side of winding core structure, the welding section of utmost point ear extends to the pole piece at least and follows the axial opposite side of winding core structure 200.
Like this, in the axial of rolling up core structure 200, because the welding section of utmost point ear extends to the relative both sides of utmost point piece in this direction, consequently, can guarantee that the thickness difference can not appear in the position of rolling up core structure 200 welding utmost point ear in this direction, compare the length of the welding section of utmost point ear in prior art in this direction and be less than the length of pole piece in this direction, the roughness on the rolling up core structure 200 surface that this embodiment provided is higher.
Specifically, the positive electrode assembly 1 includes a positive electrode plate 11 and a positive electrode tab 12, the negative electrode assembly 2 includes a negative electrode plate 21 and a negative electrode tab 22, the positive electrode plate 11 includes a positive electrode current collector 111 and a positive electrode active material 112, the negative electrode plate 21 includes a negative electrode current collector 211 and a negative electrode active material 212, the positive electrode tab 12 is welded on the positive electrode current collector 111, and the negative electrode tab 22 is welded on the negative electrode current collector 211; the winding start end of the positive electrode current collector 111 and the winding start end of the negative electrode current collector 211 are disposed in a staggered manner, and the winding start end of one of the positive electrode current collector 111 and the negative electrode current collector 211 surrounds the winding start end of the other.
In a specific embodiment of the present embodiment, the winding start end of the positive electrode collector 111 surrounds the winding start end of the negative electrode collector 211.
The positive electrode current collector 111 may be an aluminum foil, the negative electrode current collector 211 may be a copper foil, the positive electrode active material 112 may be lithium cobaltate, a ternary material, or the like, and the negative electrode active material 212 may be artificial graphite, natural graphite, carbon spheres, lithium titanate, or the like, and the types of the positive electrode current collector 111, the negative electrode current collector 211, the positive electrode active material 112, and the negative electrode active material 212 are not particularly limited.
In some optional embodiments, the length of the positive tab 12 in the axial direction of the winding core structure 200 is 5-10 mm, the thickness of the positive tab 12 is 45-110 μm, and the length of the welding section of the positive tab 12 in the axial direction of the winding core structure 200 is 0.5-1.5 mm more than the length of the positive current collector 111 in the axial direction; the length of the negative electrode tab 22 in the axial direction of the winding core structure 200 is 5-10 mm, the thickness of the negative electrode tab 22 is 45-110 μm, and the length of the welding section of the negative electrode tab 22 in the axial direction of the winding core structure 200 is 0.5-1.5 mm larger than the length of the negative electrode current collector 211 in the upward direction.
As shown in fig. 1b, in order to ensure that the core structure 200 provided by the present embodiment also has a high flatness in the radial direction, the core structure 200 provided by the present embodiment further includes a leveling member 4; at least one of the positive plate or the negative plate is provided with a leveling piece 4 in the surrounding area of the pole ear of the positive plate or the negative plate, and the leveling piece 4 is in contact with the pole ear of the positive plate or the negative plate, wherein the thickness of the leveling piece 4 is larger than or equal to that of the pole ear.
In some alternative embodiments, the leveling member 4 covers at least a region between the winding start end of the negative electrode tab 21 and an adjacent region of the winding start end of the positive electrode tab 11 in the radial direction of the jelly roll structure 200.
Specifically, the positive electrode current collector 111 has a stepped portion 1111 at the core portion of the jelly roll structure 200, wherein the stepped portion 1111 is located in an adjacent region of the winding start end of the positive electrode sheet 11 in the radial direction of the jelly roll structure 200, and the leveling member 4 extends from the winding start end of the negative electrode sheet 21 to the stepped portion 1111.
Therefore, the thickness of the two sides of the pole lug can be prevented from being smaller than that of the pole lug, and the core winding structure 200 is guaranteed to have higher flatness in the radial direction.
Further, in the present embodiment, the thickness of the leveling member 4 at each position in the length direction of the pole piece is less than 10 μm at the maximum difference. In this way, the flatness of the surface of the jelly roll structure 200 can be further improved.
Fig. 3a is a schematic structural diagram of a negative electrode assembly in a winding core structure provided by an embodiment of the application. Fig. 3b is a schematic structural diagram of the unwound negative electrode assembly in the winding core structure according to the embodiment of the present application. Fig. 4a is a schematic structural diagram of a positive electrode assembly in a winding core structure provided by an embodiment of the present application. Fig. 4b is a schematic structural diagram of the unwound positive electrode assembly in the winding core structure according to the embodiment of the present application.
In some alternative embodiments, the leveling member 4 is a gummed paper, the gummed paper includes a filling gummed paper 41 and a tab gummed paper 42, the areas on the two sides of the tab along the length direction of the pole piece are respectively filled with the filling gummed paper 41, and the tab gummed paper 42 covers the tab and the filling gummed paper 41.
The adhesive tape is an insulating adhesive tape, and the adhesive tape is provided to prevent burrs generated in the welding process from piercing the separator 3. Wherein, the thickness of the gummed paper should be larger than the height of the burr.
In some embodiments, the length of the filling adhesive paper 41 in the radial direction of the core structure 200 is 2-20 mm.
Further, in the embodiment, the absolute value of the difference between the thickness of the filling adhesive tape 41 and the thickness of the tab is 8-12 μm; the absolute value of the difference between the length of the tab gummed paper 42 in the length direction of the pole piece and the sum of the lengths of the covered tab and the filling gummed paper 41 in the length direction is 0-3 mm. In this way, it is further ensured that the jelly roll structure 200 has a good flatness in both the radial and axial directions.
Specifically, the filling adhesive tape 41 includes a positive filling adhesive tape 41a and a negative filling adhesive tape 41b, and the tab adhesive tape 42 includes a positive tab adhesive tape 42a and a negative tab adhesive tape 42 b; two pieces of positive electrode filling adhesive tape 41a and negative electrode filling adhesive tape 41b are provided; the positive electrode filling adhesive tape 41a includes a first positive electrode filling adhesive tape 411a and a second positive electrode filling adhesive tape 412a, the first positive electrode filling adhesive tape 411a is disposed between the step portion 1111 and the positive electrode tab 12, and the second positive electrode filling adhesive tape 412a is disposed between one end of the positive electrode tab 12 close to the winding start end of the positive electrode current collector 111 and the winding start end of the positive electrode current collector 111; the negative electrode filling gummed paper 41b includes a first negative electrode filling gummed paper 411b and a second negative electrode filling gummed paper 412b, the first negative electrode filling gummed paper 411b is arranged between the winding starting end of the positive electrode current collector 111 and one end of the negative electrode tab 22 departing from the winding starting end of the negative electrode current collector 211, and the second negative electrode filling gummed paper 412b is arranged between one end of the negative electrode tab 22 close to the winding starting end of the negative electrode current collector 211 and the winding starting end of the negative electrode current collector 211; the positive tab gummed paper 42a includes a first positive tab gummed paper 421a and a second positive tab gummed paper 422a, the first positive tab gummed paper 421a is disposed on one side of the positive tab 12 departing from the positive current collector 111, and the second positive tab gummed paper 422a is disposed on one side of the positive current collector 111 departing from the tab 12; the negative tab adhesive 42b is disposed on a side of the negative tab 22 away from the negative current collector 211.
Further, in a specific embodiment of this example, the thickness of positive electrode filling adhesive 41a is equal to the thickness of positive electrode tab 12, and the thickness of negative electrode filling adhesive 41b is equal to the thickness of negative electrode tab 22.
In order to avoid the uneven thickness phenomenon at the winding start end of the positive electrode collector 111 and the winding start end of the negative electrode collector 211, in the present embodiment, the negative electrode active material 212 has a single-sided region with an active material coated on one side at the core portion of the jelly roll structure 200, the single-sided region has a bent portion 2121, and the winding start end of the single-sided region, the winding start end of the active material of the positive electrode sheet 11, and the step portion are located at the same radial position of the jelly roll structure 200. In this way, it can be ensured that the thickness at the winding start end of the positive electrode current collector 111 and the winding start end of the negative electrode current collector 211 is uniform, so as to further improve the flatness of the jelly roll structure provided by the present embodiment.
Further, when the roll core structure 200 provided by the present embodiment is unwound, the absolute value of the difference between the distance between the leveling member 4 and the active material of the positive electrode tab 11 and twice the tab thickness is less than 1 mm. Like this, can further guarantee to roll up the thickness on core structure 200 surface even in core structure 200's the footpath to promote core structure 200's roughness.
In an alternative embodiment, the dimensions of the positive electrode assembly 1 and the negative electrode assembly 2 are as follows, in particular,
when the core structure 200 is unwound: the length of the positive electrode current collector 111 in the axial direction of the jelly roll structure 200 is 75.5mm, the distance between the winding start end of the positive electrode current collector 111 and the end of the positive electrode active material 112 close to the winding start end of the positive electrode current collector 111 is 26mm, the thickness of the positive electrode tab 12 is 80 μm, the length of the positive electrode tab 12 in the radial direction of the jelly roll structure 200 is 6mm, the distance between the end of the positive electrode tab 12 away from the winding start end of the positive electrode current collector 111 and the end of the positive electrode active material 112 close to the winding start end of the positive electrode current collector 111 is 10mm, and the distance between the end of the positive electrode tab 12 close to the winding start end of the positive electrode current collector 111 and the winding start end of the positive electrode current collector 111 is 10 mm;
the length of the negative electrode current collector 211 in the axial direction of the jelly roll structure 200 is 77.5mm, the distance between the winding start end of the negative electrode current collector 211 and one end of the negative electrode active material 212 close to the winding start end of the negative electrode current collector 211 is 55mm, the thickness of the negative electrode tab 22 is 80 μm, the length of the negative electrode tab 22 in the radial direction of the jelly roll structure 200 is 6mm, the distance between one end of the negative electrode tab 22 away from the winding start end of the negative electrode current collector 211 and one end of the negative electrode active material 212 close to the winding start end of the negative electrode current collector 211 is 36mm, and the distance between one end of the negative electrode tab 22 close to the winding start end of the negative electrode current collector 211 and the winding start end of the negative electrode current collector 211;
after the winding core structure 200 is wound: the distance between one end of the positive electrode tab 12 close to the winding start end of the positive electrode collector 111 and one end of the negative electrode tab 22 away from the winding start end of the negative electrode collector 211 was 11 mm.
In the winding core structure provided in the embodiment of the present application, the thickness of the negative tab adhesive paper 42b is equal to the thickness of the positive electrode collector 111, the thickness of the positive tab 12, the thickness of the first positive tab adhesive paper 421a, the thickness of the second positive tab adhesive paper 422a, and the thickness of the negative tab 22. Specific values of the thickness of the negative electrode tab sheet 42b are not described here.
In an alternative embodiment, the membrane 3 has a thickness of 9 μm.
Fig. 5a is a state diagram of an axial cutting of the core structure provided in the embodiment of the present application. Fig. 5b is a state diagram of radial cutting of the winding core structure provided by the embodiment of the application.
As shown in FIGS. 5a and 5b, A-A, B-B, C-C, D-D, E-E are different cross-sections of the axial cut of the core structure 200, respectively; F-F, G-G are different cross-sections of the radial cut of the core structure 200.
As shown in the following table, tables 1 to 4 are comparison tables of the parameters of the winding core structure of the present application and the parameters of the winding core structure of the prior art; table 5 and table 6 are the whole parameter contrast table of this application core structure and prior art core structure.
The above-mentioned parameters of the winding core structure provided by the present application include (positive, negative) tab thickness, (positive, negative) tab length in the axial direction of the winding core structure, positive tab welding section length in the axial direction of the winding core structure, negative tab welding section length in the axial direction of the winding core structure, first positive filling adhesive tape length in the extending direction of the positive plate, second positive filling adhesive tape length in the extending direction of the positive plate, first (second) positive tab adhesive tape length in the extending direction of the positive plate, first negative filling adhesive tape length in the extending direction of the negative plate, second negative filling adhesive tape length in the extending direction of the negative plate, and negative tab adhesive tape length in the extending direction of the negative plate; the above-mentioned parameters of the prior art roll core structure include the thickness of the positive and negative tabs, the lengths of the positive and negative tabs in the axial direction of the roll core structure, the length of the positive tab welding section in the axial direction of the roll core structure, the length of the negative tab welding section in the axial direction of the roll core structure, the length of the positive adhesive tape in the extending direction of the positive tab, and the length of the negative adhesive tape in the extending direction of the positive tab; the whole parameters of the winding core structure comprise the thickness of a winding core at the position A-A, the thickness of a winding core at the position B-B, the thickness of a winding core at the position C-C, the thickness of a winding core at the position D-D, the thickness of a winding core at the position E-E, the thickness of a winding core at the position F-F, the thickness of a winding core at the position G-G, the flatness, the retention rate of the circulating capacity and the expansion of the winding core; the whole parameters of the winding core structure in the prior art comprise the thickness of a winding core at A-A, the thickness of a winding core at B-B, the thickness of a winding core at C-C, the thickness of a winding core at D-D, the thickness of a winding core at E-E, the thickness of a winding core at F-F, the thickness of a winding core at G-G, the flatness, the retention rate of the circulating capacity and the expansion of the winding core.
In the following, three different sets of data in the present application are referred to as data 1, data 2, and data 3, respectively, in comparison with the prior art.
Table 1 comparison table of winding core structure parameters of the present application and the winding core structure parameters of the prior art
Table 2 comparison table of core structure parameters and prior art parameters of the present application
Table 3 comparison table of core structure parameters and prior art parameters of the present application
Table 4 comparison table of core structure parameters and prior art parameters of the present application
TABLE 5 comparison table of overall parameters of core structure in the present application and overall parameters in the prior art
Table 6 comparison table of whole parameters of winding core structure in this application and that of winding core structure in prior art
As can be seen from the data in tables 1 to 6, firstly, the overall thickness values of the winding core structure provided by the present application at different cross sections have a small difference, while the overall thickness values of the winding core structure in the prior art at different cross sections have a large difference; secondly, the circulation capacity retention rate of the last core structure that obtains of three group parameters that this application adopted all is higher than prior art, and in addition, the core expansion rate of the last core structure that obtains of three group parameters that this application adopted all is less than prior art. From this, the roughness of the core structure that this application provided is higher.
The winding core structure provided by the embodiment comprises a positive electrode assembly, a negative electrode assembly, a diaphragm and a leveling member, wherein the positive electrode assembly, the diaphragm and the negative electrode assembly are sequentially stacked and wound together, and both the positive electrode assembly and the negative electrode assembly comprise a pole piece and a pole lug; the positive component comprises a positive plate and a positive tab, and the negative component comprises a negative plate and a negative tab; at least one of the positive plate or the negative plate is provided with a leveling piece in the surrounding area of the pole ear, the leveling piece is in contact with the pole ear, and the thickness of the leveling piece is larger than or equal to that of the pole ear. The surface smoothness of the roll core structure provided by the embodiment is better.
The embodiment further provides a lithium ion battery, which comprises the winding core structure 200 and a protection member covering the winding core structure 200. It should be noted that the lithium ion battery provided in this embodiment further includes an electrolyte filled between the winding core structure 200 and the protection member, where the protection member may be a protection film or a protection shell, and the protection film may be an aluminum-plastic film.
Note that, in the present embodiment, the types of the protective film (protective case) and the electrolytic solution are not particularly limited.
The lithium ion battery provided by the embodiment comprises a roll core structure, wherein the roll core structure comprises a positive electrode assembly, a negative electrode assembly and a diaphragm, the positive electrode assembly, the diaphragm and the negative electrode assembly are sequentially stacked and wound together, and both the positive electrode assembly and the negative electrode assembly comprise a pole piece and a pole lug; the positive component comprises a positive plate and a positive tab, and the negative component comprises a negative plate and a negative tab; at least one of the positive plate or the negative plate is provided with a leveling piece in the surrounding area of the pole ear, the leveling piece is in contact with the pole ear, and the thickness of the leveling piece is larger than or equal to that of the pole ear. The surface flatness of the winding core structure provided by the embodiment is good, so that the lithium ion battery provided by the embodiment can be prevented from expanding in the circulating process, and the circulating life of the lithium ion battery provided by the embodiment can be prolonged.
Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.
Claims (12)
1. A roll core structure is characterized by comprising a positive electrode assembly, a negative electrode assembly, a diaphragm and a leveling member, wherein the positive electrode assembly, the diaphragm and the negative electrode assembly are sequentially stacked and wound together, and both the positive electrode assembly and the negative electrode assembly comprise a pole piece and a pole lug;
the positive component comprises a positive plate and a positive tab, and the negative component comprises a negative plate and a negative tab; at least one of the positive plate or the negative plate is provided with the leveling piece in the surrounding area of the pole lug, the leveling piece is in contact with the pole lug, and the thickness of the leveling piece is larger than or equal to that of the pole lug.
2. The winding core structure of claim 1, wherein the leveling member covers at least an area between a winding start end of the negative electrode tab and an adjacent area of the winding start end of the positive electrode tab in a radial direction of the winding core structure.
3. Core structure according to claim 1 or 2, characterized in that the maximum difference in thickness of the levelling member at each point along the length of the pole piece is less than 10 μm.
4. The roll core structure of claim 1, wherein the leveling member is a glue paper, the glue paper comprises a filling glue paper and a tab glue paper, the filling glue paper is filled in areas located on two sides of the tab along the length direction of the pole piece, and the tab glue paper covers the tab and the filling glue paper.
5. The roll core structure of claim 4, wherein the absolute value of the difference between the thickness of the filling adhesive paper and the thickness of the tab is 8-12 μm.
6. The roll core structure of claim 5, wherein the absolute value of the difference between the length of the tab gummed paper in the length direction of the pole piece and the sum of the lengths of the covered tab and the filling gummed paper in the length direction is 0-3 mm.
7. The winding core structure according to any one of claims 4 to 6, wherein the pole piece comprises a current collector and an active material, and the tab is welded on the current collector; the negative plate is provided with a single-side area with one side coated with an active material at the core part of the winding core structure, and the single-side area is provided with a bending part.
8. The winding core structure of claim 7, wherein the winding starting end of the positive plate and the winding starting end of the negative plate are arranged in a staggered manner, the positive plate has a step part at the core part of the winding core structure, and the leveling member extends from the winding starting end of the negative plate to the step part.
9. The jelly roll structure of claim 8, wherein a winding start end of the single surface region, a winding start end of the active material of the positive electrode sheet, and the step portion are at the same radial position of the jelly roll structure.
10. The winding core structure of claim 8, wherein the absolute value of the difference between the distance between the leveling member and the active material of the positive tab and twice the thickness of the tab is less than 1mm when the winding core structure is unfolded.
11. The winding core structure according to claim 9 or 10, characterized in that at least part of the tab is welded to the pole piece to form a welded section of the tab, one end of the tab extending beyond one axial side of the winding core structure, the welded section of the tab extending at least to the other axial side of the pole piece along the winding core structure.
12. A lithium ion battery, comprising the winding core structure of any one of claims 1 to 11, and a protection member covering the winding core structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110334030.6A CN112928340A (en) | 2021-03-29 | 2021-03-29 | Roll up core structure and lithium ion battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110334030.6A CN112928340A (en) | 2021-03-29 | 2021-03-29 | Roll up core structure and lithium ion battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112928340A true CN112928340A (en) | 2021-06-08 |
Family
ID=76176372
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110334030.6A Pending CN112928340A (en) | 2021-03-29 | 2021-03-29 | Roll up core structure and lithium ion battery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112928340A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115513611A (en) * | 2022-10-27 | 2022-12-23 | 惠州锂威新能源科技有限公司 | Battery cell and battery cell manufacturing method |
| WO2023124570A1 (en) * | 2021-12-30 | 2023-07-06 | 珠海冠宇电池股份有限公司 | Pole piece, roll core, and battery |
| WO2024036507A1 (en) * | 2022-08-17 | 2024-02-22 | 宁德新能源科技有限公司 | Electrochemical device and electronic device |
| CN117673438A (en) * | 2024-02-02 | 2024-03-08 | 武汉星纪魅族科技有限公司 | Electrode assembly, battery cell, battery and electric equipment |
-
2021
- 2021-03-29 CN CN202110334030.6A patent/CN112928340A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023124570A1 (en) * | 2021-12-30 | 2023-07-06 | 珠海冠宇电池股份有限公司 | Pole piece, roll core, and battery |
| WO2024036507A1 (en) * | 2022-08-17 | 2024-02-22 | 宁德新能源科技有限公司 | Electrochemical device and electronic device |
| CN115513611A (en) * | 2022-10-27 | 2022-12-23 | 惠州锂威新能源科技有限公司 | Battery cell and battery cell manufacturing method |
| CN117673438A (en) * | 2024-02-02 | 2024-03-08 | 武汉星纪魅族科技有限公司 | Electrode assembly, battery cell, battery and electric equipment |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112928340A (en) | Roll up core structure and lithium ion battery | |
| CN113013377A (en) | Battery with a battery cell | |
| CN211789341U (en) | Battery cell, battery using battery cell and electronic device | |
| CN211654976U (en) | Button type lithium battery without electrode lugs | |
| CN212571274U (en) | Lithium ion battery and electronic device | |
| CN218299826U (en) | Pole piece, roll up core and battery | |
| KR20230009442A (en) | Pole Segments, Wound Battery Cells, and Batteries | |
| CN214588911U (en) | Battery with a battery cell | |
| CN214411297U (en) | Roll up core structure and lithium ion battery | |
| CN113875059B (en) | Battery cell structure and battery | |
| CN219575722U (en) | Full-tab winding core and lithium ion battery thereof | |
| CN218160539U (en) | Battery core and battery | |
| CN218160540U (en) | Battery with a battery cell | |
| CN215988907U (en) | Roll core and battery | |
| CN108808113A (en) | Secondary cell and current-collecting terminals | |
| US20180191034A1 (en) | Stacked, Rolled-Electrode Battery Cell with Y-Axis Bending | |
| CN220138390U (en) | Soft package battery and consumer | |
| CN220604925U (en) | Battery cell | |
| CN215680715U (en) | Lithium battery positive and negative plate structure and lithium battery | |
| CN218004964U (en) | Roll up core and battery | |
| CN220914293U (en) | Coiled battery cell of battery cell, battery pack and electricity utilization device | |
| WO2023184453A1 (en) | Electrochemical device and electric device | |
| CN215816063U (en) | Folding button type lithium battery | |
| CN221201205U (en) | Laminated battery cell pole piece structure, battery cell and battery | |
| CN221057474U (en) | Secondary battery, pole piece and material belt |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |