CN114566720A - Roll core assembly of battery and battery - Google Patents

Roll core assembly of battery and battery Download PDF

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Publication number
CN114566720A
CN114566720A CN202210209626.8A CN202210209626A CN114566720A CN 114566720 A CN114566720 A CN 114566720A CN 202210209626 A CN202210209626 A CN 202210209626A CN 114566720 A CN114566720 A CN 114566720A
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material layer
electrode material
negative electrode
positive electrode
per unit
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陈国�
孙振勇
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Weilai Power Technology Hefei Co Ltd
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Weilai Power Technology Hefei Co Ltd
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    • 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
    • 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
    • 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

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  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Secondary Cells (AREA)

Abstract

The invention relates to the technical field of batteries, and particularly provides a battery roll core assembly and a battery. The roll core assembly is formed by winding a negative electrode, a first diaphragm, a positive electrode and a second diaphragm which are sequentially stacked, wherein the negative electrode comprises a first negative electrode material layer, a second negative electrode material layer and a negative electrode current collector, the positive electrode comprises a first positive electrode material layer, a second positive electrode material layer and a positive electrode current collector, the ratio of the effective capacity of the second negative electrode material layer per unit area to the effective capacity of the first positive electrode material layer per unit area is increased along the direction far away from the center hole of the roll core assembly, and/or the ratio of the effective capacity of the first negative electrode material layer per unit area to the effective capacity of the second positive electrode material layer per unit area is decreased along the direction far away from the center hole of the roll core assembly. With such an arrangement, the design margin of the NP ratio can be reduced, so that waste of the negative electrode active material can be avoided or reduced and the energy density of the cell can be improved.

Description

Roll core assembly of battery and battery
Technical Field
The invention relates to the technical field of batteries, and particularly provides a battery roll core assembly and a battery.
Background
In recent years, with rapid development in the fields of power, energy storage, intelligent wearing and the like, higher and higher requirements are put forward on a battery energy storage technology.
Taking a lithium ion battery as an example, the lithium ion battery is the first choice in the battery field due to its higher energy density and more mature manufacturing technology.
Lithium ion batteries typically include several components: positive and negative electrodes capable of inserting/extracting lithium ions, a diaphragm with electronic insulation and ion transmission functions, electrolyte with lithium ion conduction function, and accessories such as current collectors, tabs and shells. Common lithium ion batteries exist in three forms, namely cylindrical, square and soft package batteries. Among them, cylindrical batteries are most popular because of their extremely high manufacturing efficiency, high performance and reliability, and durability.
As shown in fig. 1, a core assembly of a conventional cylindrical lithium ion battery is formed by winding a negative electrode 1, a first separator 3, a positive electrode 2 and a second separator 4, which are sequentially arranged, and the core assembly is inserted into a case 6 of the battery, and a battery cell is formed after a series of processes such as welding, liquid injection, sealing and the like.
In order to avoid lithium deposition of the battery core in the recycling process, the cathode material layer must cover the anode material layer in all directions, and the effective capacity of the cathode material layer must be larger than that of the anode material layer at the corresponding position, so that lithium ions in the anode active material can be completely embedded in the anode active material at the corresponding position when being de-embedded.
The ratio of the effective capacity of the negative electrode material layer to the effective capacity of the positive electrode material layer is generally referred to as NP ratio (positive-negative electrode mix ratio). NP is a very critical parameter in the design of lithium ion batteries, which not only affects the safety of lithium ion batteries, but also directly affects the cycle life and energy density of cells. In order to ensure that the battery cannot generate lithium deposition in the whole using process, the NP of the conventional lithium ion battery has a large margin compared with the design, which causes great waste of a negative electrode material.
Therefore, there is a need in the art for a new solution to the above problems.
Disclosure of Invention
The invention aims to solve or alleviate the technical problem, namely, the problem that the NP of the existing battery has large allowance compared with the design, so that the waste of the negative electrode material is large is solved or alleviated.
In a first aspect, the present invention provides a jelly roll component of a battery, the jelly roll component being formed by winding a negative electrode, a first separator, a positive electrode and a second separator, which are arranged in this order, the negative electrode including a first negative electrode material layer, a second negative electrode material layer and a negative electrode current collector located between the first negative electrode material layer and the second negative electrode material layer, the positive electrode including a first positive electrode material layer, a second positive electrode material layer and a positive electrode current collector located between the first positive electrode material layer and the second positive electrode material layer, the first separator being located between the second negative electrode material layer and the first positive electrode material layer, the second separator being located between the first negative electrode material layer and the second positive electrode material layer, wherein a ratio of an effective capacity per unit area of the second negative electrode material layer to an effective capacity per unit area of the first positive electrode material layer becomes smaller in a direction away from a central hole of the jelly roll component, and/or the ratio of the effective capacity per unit area of the first negative electrode material layer to the effective capacity per unit area of the second positive electrode material layer is increased in a direction away from the center hole of the winding core assembly.
In the above-described roll core assembly, a ratio of an effective capacity per unit area of the first negative electrode material layer to an effective capacity per unit area of the second positive electrode material layer is smaller than a ratio of an effective capacity per unit area of the second negative electrode material layer to an effective capacity per unit area of the first positive electrode material layer, and a ratio of a width of the first negative electrode material layer to a width of the second positive electrode material layer is equal to a ratio of a width of the second negative electrode material layer to a width of the first positive electrode material layer.
In the above-mentioned preferred technical solution of the roll core assembly, the area density of the second negative electrode material layer becomes smaller in a direction away from the central hole, and the area density of the first positive electrode material layer is substantially kept unchanged.
In a preferred embodiment of the above roll core assembly, the degree of compaction of the second negative electrode material layer decreases in a direction away from the central hole and the thickness of the second negative electrode material layer remains substantially unchanged, or the degree of compaction of the second negative electrode material layer decreases in a direction away from the central hole and the degree of compaction of the second negative electrode material layer remains substantially unchanged.
In the above-mentioned preferred technical solution of the roll core assembly, the area density of the second negative electrode material layer is kept substantially unchanged, and the area density of the first positive electrode material layer is increased in a direction away from the central hole.
In the above-mentioned preferred technical solution of the winding core assembly, the degree of compaction of the first positive electrode material layer becomes greater in a direction away from the central hole and the thickness of the first positive electrode material layer is substantially maintained.
In the above-mentioned preferred technical solution of the roll core assembly, the area density of the first negative electrode material layer becomes greater in a direction away from the central hole, and the area density of the second positive electrode material layer remains substantially unchanged.
In a preferred embodiment of the above roll core assembly, the degree of compaction of the first negative electrode material layer increases along a direction away from the central hole and the thickness of the first negative electrode material layer remains substantially unchanged, or the thickness of the first negative electrode material layer increases along a direction away from the central hole and the degree of compaction of the first negative electrode material layer remains substantially unchanged.
In the above-mentioned preferred technical solution of the roll core assembly, the area density of the first negative electrode material layer is kept substantially unchanged, and the area density of the second positive electrode material layer is decreased in a direction away from the central hole.
In a second aspect, the invention also provides a battery comprising the roll core assembly.
Under the condition of adopting the technical scheme, the roll core assembly is formed by winding the negative electrode, the first diaphragm, the positive electrode and the second diaphragm which are sequentially arranged, the negative electrode comprises a first negative electrode material layer, a second negative electrode material layer and a negative current collector positioned between the first negative electrode material layer and the second negative electrode material layer, the positive electrode comprises a first positive electrode material layer, a second positive electrode material layer and a positive current collector positioned between the first positive electrode material layer and the second positive electrode material layer, the first diaphragm is positioned between the second negative electrode material layer and the first positive electrode material layer, the second diaphragm is positioned between the first negative electrode material layer and the second positive electrode material layer, wherein the ratio of the effective capacity of the second negative electrode material layer per unit area to the effective capacity of the first positive electrode material layer per unit area is smaller along the direction far away from the center hole of the roll core assembly, and/or the effective capacity of the first negative electrode material layer per unit area and the effective capacity of the second positive electrode material layer per unit area are smaller The ratio of the effective capacities becomes larger in a direction away from the center hole of the core assembly. With this arrangement, the design margin of the NP ratio can be reduced, and waste of the negative electrode active material can be avoided or reduced.
Further, the ratio of the effective capacity per unit area of the first negative electrode material layer to the effective capacity per unit area of the second positive electrode material layer is smaller than the ratio of the effective capacity per unit area of the second negative electrode material layer to the effective capacity per unit area of the first positive electrode material layer. With such an arrangement, the design margin of the NP ratio can be further reduced.
In addition, the battery further provided on the basis of the technical scheme of the invention has the technical effects of the winding core assembly due to the adoption of the winding core assembly, and compared with the battery before improvement, the battery provided by the invention has small design margin of NP ratio, thereby avoiding or reducing the waste of negative electrode active materials.
Drawings
Preferred embodiments of the present invention are described below by way of example with reference to lithium ion batteries and with reference to the accompanying drawings, in which:
FIG. 1 is a schematic diagram of a lithium ion battery of the present invention;
FIG. 2 is a cross-sectional partial schematic view of a core assembly of the present invention;
FIG. 3 is a schematic diagram of the structure of an embodiment of the negative and positive electrodes of the present invention;
FIG. 4 is a schematic diagram of the structure of a second embodiment of the negative and positive electrodes of the present invention;
FIG. 5 is a schematic diagram of the structure of a third embodiment of the negative and positive electrodes of the present invention;
FIG. 6 is a schematic diagram of the structure of a fourth embodiment of the negative and positive electrodes of the present invention;
FIG. 7 is a schematic diagram of the structure of a fifth embodiment of the negative and positive electrodes of the present invention;
fig. 8 is a schematic structural view of a sixth embodiment of the negative and positive electrodes of the present invention.
List of reference numerals:
1. a negative electrode; 11. a first negative electrode material layer; 12. a second anode material layer; 13. a negative current collector; 2. a positive electrode; 21. a first positive electrode material layer; 22. a second positive electrode material layer; 23. a positive current collector; 3. a first diaphragm; 4. a second separator; 5. a central bore; 6. a housing.
Detailed Description
Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention.
For example, although the following description is given by taking a lithium ion battery as an example, the technical solution of the present invention can also be applied to other batteries having similar structures to the lithium ion battery, such as a sodium ion battery, and the like, and such adjustment and change to the application objects do not depart from the principle and scope of the present invention, and should be limited within the protection scope of the present invention.
It should be noted that in the description of the present invention, the terms "upper", "lower", "left", "right", etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for convenience of description, and do not indicate or imply that the devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
Referring first to fig. 1 and 2, wherein fig. 1 is a schematic structural diagram of a lithium ion battery of the present invention; figure 2 is a cross-sectional partial schematic view of a core assembly of the present invention.
As shown in fig. 1 and 2, the lithium ion battery of the present invention includes a case 6 and a roll core assembly located in the case 6, wherein the roll core assembly includes a negative electrode 1, a first separator 3, a positive electrode 2, and a second separator 4 stacked in sequence, the negative electrode 1, the first separator 3, the positive electrode 2, and the second separator 4 stacked in sequence are wound to form the roll core assembly, and a central hole 5 is formed at a central position of the roll core assembly after the winding is completed.
With continued reference to fig. 1 and 2, the negative electrode 1 includes a first negative electrode material layer 11, a second negative electrode material layer 12, and a negative electrode current collector 13 located between the first negative electrode material layer 11 and the second negative electrode material layer 12, the positive electrode 2 includes a first positive electrode material layer 21, a second positive electrode material layer 22, and a positive electrode current collector 23 located between the first positive electrode material layer 21 and the second positive electrode material layer 22, the first separator 3 is located between the second negative electrode material layer 12 and the first positive electrode material layer 21, and the second separator 4 is located between the first negative electrode material layer 11 and the second positive electrode material layer 22.
The negative electrode current collector 13 is generally made of copper foil, the negative electrode active materials are respectively coated on two sides of the copper foil to form a first negative electrode material layer 11 and a second negative electrode material layer 12 on two sides of the negative electrode current collector 13, the positive electrode current collector 23 is generally made of aluminum foil, and the positive electrode active materials are respectively coated on two sides of the aluminum foil to form a first positive electrode material layer 21 and a second positive electrode material layer 22 on two sides of the positive electrode current collector 23.
Wherein the ratio of the effective capacity per unit area of the second anode material layer 12 to the effective capacity per unit area of the first cathode material layer 21 becomes smaller in a direction away from the center hole 5 of the jelly roll assembly, and/or the ratio of the effective capacity per unit area of the first anode material layer 11 to the effective capacity per unit area of the second cathode material layer 22 becomes larger in a direction away from the center hole 5 of the jelly roll assembly.
With this arrangement, the design margin of the NP ratio can be reduced, and waste of the negative electrode active material can be avoided or reduced.
Specifically, as shown in fig. 2, during the use of the battery, lithium ions deintercalated from the first cathode material layer 21 are intercalated into the second anode material layer 12 at the corresponding position through the first separator 3, and in order to avoid the occurrence of lithium deposition, the effective capacity of the second anode material layer 12 must be larger than that of the first cathode material layer 21 at the corresponding position.
For the sake of easy understanding, the ratio of the effective capacity of the second negative electrode material layer 12 to the effective capacity of the first positive electrode material layer 21 per turn, that is, NP ratio (L) is calculated in units of turnsS2×a×Qs2)/(Ln1×b×Qn1) Wherein L isS2Is the arc length of the second anode material layer 12, a is the width of the second anode material layer 12, Qs2Ln is an effective capacity per unit area of the second anode material layer 121Is the arc length of the first positive electrode material layer 21, b is the width of the first positive electrode material layer 21, Qn1Is the effective capacity per unit area of the first cathode material layer 21.
The height of the battery (or the length of the battery) is fixed, that is, the width a of the second negative electrode material layer 12 and the width b of the first positive electrode material layer 21 are both fixed values, and in the design of the conventional lithium ion battery, the effective capacity Qs per unit area of the second negative electrode material layer 122And effective capacity Qn per unit area of the first positive electrode material layer 211Are also fixed values.
As can be seen from fig. 2, the first positive electrode material layer 21 is surrounded outside the second negative electrode material layer 12, so the arc length Ln of the first positive electrode material layer 211Greater than the arc length L of the corresponding second anode material layer 12S2L as the winding diameter of the core assembly increasesS2And Ln1The ratio of (b) is increased, so the ratio of NP per turn is also increased, i.e., the smaller the NP ratio closer to the center hole 5 of the core assembly, the larger the NP ratio farther from the center hole 5 of the core assembly.
Assuming that the ratio of the effective capacity of the second anode material layer 12 of the first turn (closest to the center hole 5 of the winding core assembly) to the effective capacity of the first cathode material layer 21, that is, the NP ratio is designed to be 1.1, the NP ratio of the fifth turn may reach 1.4, the total NP ratio of the second anode material layer 12 to the first cathode material layer 21 may approach 1.3, and the NP ratio is too large to be a design margin, resulting in a great waste of the anode active material.
In the present invention, the ratio of the effective capacity per unit area of the second anode material layer 12 to the effective capacity per unit area of the first cathode material layer 21 becomes smaller in a direction away from the center hole 5 of the winding core assembly.
Thus, L is expressed as the winding diameter of the core assembly increasesS2And Ln1Is getting larger, however, Qs2And Qn1The ratio of (b) is decreased, so that the NP ratio per odd-numbered turn (1, 3, 5 …) can be kept constant or the amount of change is small, and waste of the negative electrode active material can be avoided or reduced.
Similarly, as shown in fig. 2, during the use of the battery, lithium ions deintercalated from the second cathode material layer 22 are intercalated into the corresponding position of the first anode material layer 11 through the second separator 4, and in order to avoid lithium deposition, the effective capacity of the first anode material layer 11 must be greater than that of the corresponding position of the second cathode material layer 22.
Also, in units of circles, the ratio of the effective capacity of the first negative electrode material layer 11 to the effective capacity of the second positive electrode material layer 22 per circle, that is, the NP ratio (L) isS1×a×Qs1)/(Ln2×b×Qn2) Wherein L isS1Is the arc length of the first anode material layer 11, a is the width of the first anode material layer 11, Qs1Ln is an effective capacity per unit area of the first anode material layer 112Is the arc length of the second positive electrode material layer 22, b is the width of the second positive electrode material layer 22, Qn2Is the effective capacity per unit area of the second cathode material layer 22.
In the conventional lithium ion battery, the width a of the first negative electrode material layer 11 and the effective capacity Qs per unit area of the first negative electrode material layer 11 are set1Width b of the second positive electrode material layer 22, and effective capacity Qn per unit area of the second positive electrode material layer 222Are all fixed values.
As can be seen from fig. 2, the first negative electrode material layer 11 is surrounded on the outer side of the second positive electrode material layer 22, so the arc length L of the first negative electrode material layer 11S1Greater than arc length Ln of corresponding location of second positive electrode material layer 222L as the winding diameter of the core assembly increasesS1And Ln2The ratio of (A) is smaller and the ratio of NP per turn is smaller, i.e. the ratio of NP closer to the central opening 5 of the core assembly is larger and farther from the coreThe smaller the NP ratio of the central bore 5 of the assembly.
Assuming that the ratio of the effective capacity of the first anode material layer 11 to the effective capacity of the second cathode material layer 22 of the sixth turn (farthest from the center hole 5 of the winding core assembly), that is, the NP ratio is designed to be 1.1, the NP ratio of the second turn may reach 1.4, the total NP ratio of the first anode material layer 11 to the second cathode material layer 22 may approach 1.3, and the NP ratio is too large as a design margin, causing a great waste of the anode active material.
In the present invention, the ratio of the effective capacity per unit area of the first negative electrode material layer 11 to the effective capacity per unit area of the second positive electrode material layer 22 is increased in a direction away from the center hole 5 of the winding core assembly.
Thus, L is expressed as the winding diameter of the core assembly increasesS1And Ln2Is getting smaller, but Qs1And Qn2The ratio of (2) to (6) is increased so that the NP ratio per even-numbered turn (2, 4, 6 …) is kept constant or the amount of change is small, and thus waste of the anode active material can be avoided or reduced.
Preferably, the ratio of the effective capacity per unit area of the first anode material layer 11 to the effective capacity per unit area of the second cathode material layer 22 is smaller than the ratio of the effective capacity per unit area of the second anode material layer 12 to the effective capacity per unit area of the first cathode material layer 21, and the ratio of the width of the first anode material layer 11 to the width of the second cathode material layer 22 is equal to the ratio of the width of the second anode material layer 12 to the width of the first cathode material layer 21.
Namely, QS1/Qn2＜QS2/Qn1With such an arrangement, the design margin of the NP ratio can be further reduced.
Specifically, in the design of the conventional lithium ion battery, the effective capacity Q per unit area of the first negative electrode material layer 11S1And the effective capacity per unit area Q of the second anode material layer 12S2Similarly, the effective capacity per unit area Qn of the first positive electrode material layer 211And the effective capacity per unit area Qn of the second positive electrode material layer 222And also the same, then QS1/Qn2＝QS2/Qn1。
As can be seen from fig. 2, the first positive electrode material layer 21 is surrounded outside the second negative electrode material layer 12, so the arc length Ln of the first positive electrode material layer 211Greater than the arc length L of the corresponding second anode material layer 12S2Then L isS2/n1Less than 1; the first cathode material layer 11 is surrounded on the outer side of the second cathode material layer 22, so the arc length L of the first cathode material layer 11S1Greater than arc length Ln of corresponding location of second positive electrode material layer 222Then L isS1/Ln2＞1。
Exemplarily, LS2/n1＝0.8，LS1/Ln21.1, and 1.05, and the ratio NP of the effective capacity of the second anode material layer 12 to the effective capacity of the first cathode material layer 211＝1.1；
Then, QS2/Qn1＝NP1÷(LS2/n1×a/b)＝1.1÷(0.8×1.05)≈1.31；
Then, Qs1/Qn2＝QS2/Qn1≈1.31；
Then, the ratio NP of the effective capacity of the first anode material layer 11 to the effective capacity of the second cathode material layer 222＝LS1/Ln2×a/b×Qs1/Qn2＝1.1×1.05×1.31≈1.51，NP2And NP1The difference is large.
Whereas in the present invention, Qs is1/Qn2＜QS2/Qn1Following the example above, QS2/Qn1When the value is 1.31, Qs can be converted into1/Qn2The design is 1.0 of the total weight of the material,
then, NP2＝LS1/Ln2×a/b×Qs1/Qn2＝1.1×1.05×1.0＝1.16，NP2And NP1With a small phase difference, Qs can also be adjusted1/Qn2The design is that the design is 0.95,
then, NP2＝LS1/Ln2×a/b×Qs1/Qn2＝1.1×1.05×0.95≈1.1，NP2And NP1The same is true.
It should be noted that, in practical applications, the effective capacity per unit area of the first negative electrode material layer 11 may be equal to the effective capacity per unit area of the second negative electrode material layer 12, and the effective capacity per unit area of the first positive electrode material layer 21 may be smaller than the effective capacity per unit area of the second positive electrode material layer 22, or the effective capacity per unit area of the first positive electrode material layer 21 may be equal to the effective capacity per unit area of the second positive electrode material layer 22, and the effective capacity per unit area of the first negative electrode material layer 11 may be smaller than the effective capacity per unit area of the second negative electrode material layer 12, and so on, which can be flexibly adjusted and changed without departing from the principle and scope of the present invention, and should be limited within the protection scope of the present invention.
The technical solution of the present invention will be described in detail below with reference to six specific embodiments.
Implement one
A first embodiment of the present invention will be described in detail with reference to fig. 3.
As shown in fig. 3, the negative electrode 1 of the present embodiment includes a first negative electrode material layer 11, a second negative electrode material layer 12, and a negative electrode current collector 13, wherein the first negative electrode material layer 11 is disposed on an upper surface of the negative electrode current collector 13, and the second negative electrode material layer 12 is disposed on a lower surface of the negative electrode current collector 13.
With reference to fig. 3, the positive electrode 2 of the present embodiment includes a first positive electrode material layer 21, a second positive electrode material layer 22, and a positive electrode current collector 23, wherein the first positive electrode material layer 21 is disposed on an upper surface of the positive electrode current collector 23, and the second positive electrode material layer 22 is disposed on a lower surface of the positive electrode current collector 23.
Illustratively, when the winding core assembly is manufactured, winding is started by taking the left ends of the negative electrode 1 and the positive electrode 2 as starting ends, after the winding is completed, the left ends of the negative electrode 1 and the positive electrode 2 are close to the central hole 5 of the winding core assembly, and the right ends of the negative electrode 1 and the positive electrode 2 are far away from the central hole 5 of the winding core assembly.
With continued reference to fig. 3, the area density of the second anode material layer 12 decreases in a direction away from the central hole 5, i.e., the area density of the second anode material layer 12 decreases from left to right; the areal density of the first cathode material layer 21 remains substantially unchanged.
When the area density of the second negative electrode material layer 12 is decreased, the effective capacity per unit area of the second negative electrode material layer 12 is decreased, and when the area density of the first positive electrode material layer 21 is kept substantially constant, the effective capacity per unit area of the first positive electrode material layer 21 is also kept substantially constant, and the ratio of the effective capacity per unit area of the second negative electrode material layer 12 to the effective capacity per unit area of the corresponding first positive electrode material layer 21 is decreased in a direction away from the center hole 5.
With continued reference to fig. 3, the degree of compaction of the second anode material layer 12 becomes smaller in a direction away from the central aperture 5 and the thickness of the second anode material layer 12 remains substantially constant. That is, the degree of compaction of the second anode material layer 12 becomes smaller from left to right, and the effective capacity per unit area becomes smaller as the degree of compaction becomes smaller while the thickness is kept substantially constant.
With continued reference to fig. 3, the area density of the first negative electrode material layer 11 becomes greater in a direction away from the central hole 5, that is, the area density of the first negative electrode material layer 11 becomes greater from left to right; the areal density of the second positive electrode material layer 22 remains substantially unchanged.
When the area density of the first negative electrode material layer 11 is increased, the effective capacity per unit area of the first negative electrode material layer 11 is increased, and the area density of the second positive electrode material layer 22 is maintained substantially constant, the effective capacity per unit area of the second positive electrode material layer 22 is also maintained substantially constant, and the ratio of the effective capacity per unit area of the first negative electrode material layer 11 to the effective capacity per unit area of the corresponding second positive electrode material layer 22 is increased in a direction away from the center hole 5.
With continued reference to fig. 3, the degree of compaction of first anode material layer 11 increases in a direction away from central aperture 5 and the thickness of first anode material layer 11 remains substantially constant. That is, the degree of compaction of the first negative electrode material layer 11 increases from left to right, and when the thickness is substantially constant, the degree of compaction increases, and the effective capacity per unit area increases accordingly.
Example two
A second embodiment of the present invention will be described in detail with reference to fig. 4.
As shown in fig. 4, on the basis of the other setting conditions in the first embodiment being unchanged, in the present embodiment, the thickness of the second anode material layer 12 becomes smaller in the direction away from the center hole 5 and the degree of compaction of the second anode material layer 12 remains substantially unchanged. That is, the thickness of the second anode material layer 12 decreases from left to right, and the effective capacity per unit area decreases as the thickness decreases while the degree of compaction remains substantially unchanged.
The thickness of the first anode material layer 11 becomes larger in a direction away from the center hole 5 and the degree of compaction of the first anode material layer 11 is substantially maintained. That is, the thickness of the first negative electrode material layer 11 increases from left to right, and when the degree of compaction is substantially maintained, the thickness increases, and the effective capacity per unit area increases accordingly.
EXAMPLE III
A third embodiment of the present invention will be described in detail with reference to fig. 5.
As shown in fig. 5, similarly to the embodiment, the negative electrode 1 of the present embodiment includes a first negative electrode material layer 11, a second negative electrode material layer 12, and a negative electrode current collector 13, wherein the first negative electrode material layer 11 is disposed on an upper surface of the negative electrode current collector 13, and the second negative electrode material layer 12 is disposed on a lower surface of the negative electrode current collector 13; the positive electrode 2 includes a first positive electrode material layer 21, a second positive electrode material layer 22, and a positive electrode current collector 23, wherein the first positive electrode material layer 21 is disposed on an upper surface of the positive electrode current collector 23, and the second positive electrode material layer 22 is disposed on a lower surface of the positive electrode current collector 23.
Illustratively, when the winding core assembly is manufactured, the left ends of the negative electrode 1 and the positive electrode 2 are taken as starting ends, after winding is completed, the left ends of the negative electrode 1 and the positive electrode 2 are close to the central hole 5 of the winding core assembly, and the right ends of the negative electrode 1 and the positive electrode 2 are far away from the central hole 5 of the winding core assembly.
With continued reference to fig. 5, the areal density of the second anode material layer 12 remains substantially unchanged; the area density of the first cathode material layer 21 becomes large in a direction away from the center hole 5, that is, the area density of the first cathode material layer 21 becomes large from left to right.
When the area density of the first cathode material layer 21 is increased, the effective capacity per unit area of the first cathode material layer 21 is increased, and the area density of the second anode material layer 12 is kept substantially constant, the effective capacity per unit area of the second anode material layer 12 is also kept substantially constant, and the ratio of the effective capacity per unit area of the second anode material layer 12 to the effective capacity per unit area of the corresponding first cathode material layer 21 is decreased in a direction away from the center hole 5.
With continued reference to fig. 5, the degree of compaction of the first positive electrode material layer 21 becomes greater in a direction away from the central hole 5 and the thickness of the first positive electrode material layer 21 remains substantially constant. That is, the degree of compaction of the first positive electrode material layer 21 increases from left to right, and when the thickness is kept substantially constant, the degree of compaction increases, and the effective capacity per unit area increases accordingly.
With continued reference to fig. 5, the area density of the first negative electrode material layer 11 becomes greater in a direction away from the central hole 5, that is, the area density of the first negative electrode material layer 11 becomes greater from left to right; the areal density of the second positive electrode material layer 22 remains substantially unchanged.
When the area density of the first negative electrode material layer 11 is increased, the effective capacity per unit area of the first negative electrode material layer 11 is increased, and the area density of the second positive electrode material layer 22 is maintained substantially constant, the effective capacity per unit area of the second positive electrode material layer 22 is also maintained substantially constant, and the ratio of the effective capacity per unit area of the first negative electrode material layer 11 to the effective capacity per unit area of the corresponding second positive electrode material layer 22 is increased in a direction away from the center hole 5.
With continued reference to fig. 5, the degree of compaction of first anode material layer 11 increases in a direction away from central aperture 5 and the thickness of first anode material layer 11 remains substantially constant. That is, the degree of compaction of the first negative electrode material layer 11 increases from left to right, and when the thickness is substantially constant, the degree of compaction increases, and the effective capacity per unit area increases accordingly.
Practice four
A fourth embodiment of the present invention will be described in detail with reference to fig. 6.
As shown in fig. 6, similarly to the first embodiment, in the present embodiment, the negative electrode 1 includes a first negative electrode material layer 11, a second negative electrode material layer 12, and a negative electrode current collector 13, wherein the first negative electrode material layer 11 is provided on an upper surface of the negative electrode current collector 13, and the second negative electrode material layer 12 is provided on a lower surface of the negative electrode current collector 13; the positive electrode 2 includes a first positive electrode material layer 21, a second positive electrode material layer 22, and a positive electrode current collector 23, wherein the first positive electrode material layer 21 is disposed on an upper surface of the positive electrode current collector 23, and the second positive electrode material layer 22 is disposed on a lower surface of the positive electrode current collector 23.
Illustratively, when the winding core assembly is manufactured, the left ends of the negative electrode 1 and the positive electrode 2 are taken as starting ends, after winding is completed, the left ends of the negative electrode 1 and the positive electrode 2 are close to the central hole 5 of the winding core assembly, and the right ends of the negative electrode 1 and the positive electrode 2 are far away from the central hole 5 of the winding core assembly.
With continued reference to fig. 6, the area density of the second anode material layer 12 becomes smaller in a direction away from the central hole 5, i.e. the area density of the second anode material layer 12 becomes smaller from left to right; the areal density of the first cathode material layer 21 remains substantially unchanged.
When the area density of the second negative electrode material layer 12 is decreased, the effective capacity per unit area of the second negative electrode material layer 12 is decreased, and when the area density of the first positive electrode material layer 21 is kept substantially constant, the effective capacity per unit area of the first positive electrode material layer 21 is also kept substantially constant, and the ratio of the effective capacity per unit area of the second negative electrode material layer 12 to the effective capacity per unit area of the corresponding first positive electrode material layer 21 is decreased in a direction away from the center hole 5.
With continued reference to fig. 6, the degree of compaction of the second anode material layer 12 decreases in a direction away from the central aperture 5 and the thickness of the second anode material layer 12 remains substantially constant, i.e., the degree of compaction of the second anode material layer 12 decreases from left to right. In the case where the thickness is kept substantially constant, the degree of compaction becomes small, and the effective capacity per unit area becomes small.
With continued reference to fig. 6, the areal density of the first negative electrode material layer 11 remains substantially unchanged; the area density of the second cathode material layer 22 becomes smaller in a direction away from the center hole 5, that is, the area density of the second cathode material layer 22 becomes smaller from left to right.
When the area density of the second cathode material layer 22 is decreased, the effective capacity per unit area of the second cathode material layer 22 is decreased, and the area density of the first anode material layer 11 is kept substantially constant, the effective capacity per unit area of the first anode material layer 11 is also kept substantially constant, and the ratio of the effective capacity per unit area of the first anode material layer 11 to the effective capacity per unit area of the corresponding second cathode material layer 22 is increased in a direction away from the center hole 5.
With continued reference to fig. 6, the degree of compaction of the second positive electrode material layer 22 becomes smaller in a direction away from the central hole 5 and the thickness of the second positive electrode material layer 22 remains substantially constant. That is, the degree of compaction of the second cathode material layer 22 decreases from left to right, and the effective capacity per unit area decreases as the degree of compaction decreases while the thickness remains substantially unchanged.
Practice five
A fifth embodiment of the present invention will be described in detail with reference to fig. 7.
As shown in fig. 7, similarly to the first embodiment, in the present embodiment, the negative electrode 1 includes a first negative electrode material layer 11, a second negative electrode material layer 12, and a negative electrode collector 13, wherein the first negative electrode material layer 11 is provided on an upper surface of the negative electrode collector 13, and the second negative electrode material layer 12 is provided on a lower surface of the negative electrode collector 13; the positive electrode 2 includes a first positive electrode material layer 21, a second positive electrode material layer 22, and a positive electrode current collector 23, wherein the first positive electrode material layer 21 is disposed on an upper surface of the positive electrode current collector 23, and the second positive electrode material layer 22 is disposed on a lower surface of the positive electrode current collector 23.
Illustratively, when the winding core assembly is manufactured, the left ends of the negative electrode 1 and the positive electrode 2 are taken as starting ends, after winding is completed, the left ends of the negative electrode 1 and the positive electrode 2 are close to the central hole 5 of the winding core assembly, and the right ends of the negative electrode 1 and the positive electrode 2 are far away from the central hole 5 of the winding core assembly.
With continued reference to fig. 7, the areal density of the second anode material layer 12 remains substantially unchanged; the area density of the first cathode material layer 21 becomes large in a direction away from the center hole 5, that is, the area density of the first cathode material layer 21 becomes large from left to right.
As the area density of the first cathode material layer 21 increases, the effective capacity per unit area of the first cathode material layer 21 increases, and as the area density of the second anode material layer 12 remains substantially unchanged, the effective capacity per unit area of the second anode material layer 12 also remains substantially unchanged, and the ratio of the effective capacity per unit area of the second anode material layer 12 to the effective capacity per unit area of the corresponding first cathode material layer 21 decreases in a direction away from the center hole 5.
With continued reference to fig. 7, the degree of compaction of the first cathode material layer 21 becomes greater in a direction away from the central hole 5 and the thickness of the first cathode material layer 21 remains substantially constant. That is, the degree of compaction of the first cathode material layer 21 increases from left to right, and in the case where the thickness is substantially constant, the degree of compaction increases, and the effective capacity per unit area increases accordingly.
With continued reference to fig. 7, the areal density of the first negative electrode material layer 11 remains substantially unchanged; the area density of the second cathode material layer 22 becomes smaller in a direction away from the center hole 5, that is, the area density of the second cathode material layer 22 becomes smaller from left to right.
When the area density of the second cathode material layer 22 is decreased, the effective capacity per unit area of the second cathode material layer 22 is decreased, and the area density of the first anode material layer 11 is kept substantially constant, the effective capacity per unit area of the first anode material layer 11 is also kept substantially constant, and the ratio of the effective capacity per unit area of the first anode material layer 11 to the effective capacity per unit area of the corresponding second cathode material layer 22 is increased in a direction away from the center hole 5.
With continued reference to fig. 7, the degree of compaction of the second positive electrode material layer 22 decreases in a direction away from the central hole 5 and the thickness of the second positive electrode material layer 22 remains substantially unchanged, i.e., the degree of compaction of the second positive electrode material layer 22 decreases from left to right, and in the case where the thickness remains substantially unchanged, the degree of compaction decreases and the effective capacity per unit area decreases accordingly.
Example six
A sixth embodiment of the present invention will be described in detail with reference to fig. 8.
As shown in fig. 8, in the fifth embodiment, on the basis of the other installation conditions being unchanged, in the present embodiment, the thickness of the first cathode material layer 21 becomes larger in the direction away from the central hole 5 and the degree of compaction of the first cathode material layer 21 remains substantially unchanged, that is, the thickness of the first cathode material layer 21 becomes larger from left to right, and in the case where the degree of compaction remains substantially unchanged, the thickness becomes larger and the effective capacity per unit area becomes larger accordingly.
The thickness of the second cathode material layer 22 decreases in a direction away from the central hole 5 and the degree of compaction of the second cathode material layer 22 remains substantially unchanged, that is, the thickness of the second cathode material layer 22 decreases from left to right, and in the case where the degree of compaction remains substantially unchanged, the thickness decreases and the effective capacity per unit area decreases accordingly.
In summary, in order to solve the problem that the NP ratio of the conventional lithium ion battery is larger than the design margin, the present invention designs a non-uniform electrode, that is, the surface density of the electrode has design variation along the length direction of the electrode, and by using the non-uniform electrode, the design margin of the NP ratio can be greatly reduced.
So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.

Claims (10)

1. A roll core component of a battery is characterized in that the roll core component comprises a negative electrode, a first diaphragm, a positive electrode and a second diaphragm which are sequentially stacked, the negative electrode, the first diaphragm, the positive electrode and the second diaphragm which are sequentially stacked are wound to form the roll core component, the negative electrode comprises a first negative electrode material layer, a second negative electrode material layer and a negative current collector positioned between the first negative electrode material layer and the second negative electrode material layer, the positive electrode comprises a first positive electrode material layer, a second positive electrode material layer and a positive current collector positioned between the first positive electrode material layer and the second positive electrode material layer, the first diaphragm is positioned between the second negative electrode material layer and the first positive electrode material layer, and the second diaphragm is positioned between the first negative electrode material layer and the second positive electrode material layer,
wherein the ratio of the effective capacity per unit area of the second anode material layer to the effective capacity per unit area of the first cathode material layer is smaller in a direction away from the center hole of the winding core assembly, and/or
The ratio of the effective capacity per unit area of the first negative electrode material layer to the effective capacity per unit area of the second positive electrode material layer is increased in a direction away from the center hole of the winding core assembly.
2. The wound core assembly of claim 1, wherein a ratio of the effective capacity per unit area of the first negative electrode material layer to the effective capacity per unit area of the second positive electrode material layer is less than a ratio of the effective capacity per unit area of the second negative electrode material layer to the effective capacity per unit area of the first positive electrode material layer, and
the ratio of the width of the first negative electrode material layer to the width of the second positive electrode material layer is equal to the ratio of the width of the second negative electrode material layer to the width of the first positive electrode material layer.
3. The core assembly of claim 1, wherein the second layer of cathode material has an areal density that decreases in a direction away from the central aperture, and the first layer of cathode material has an areal density that remains substantially unchanged.
4. The core assembly of claim 3, wherein the compaction of the second layer of negative electrode material decreases in a direction away from the central aperture and the thickness of the second layer of negative electrode material remains substantially constant, or
The thickness of the second anode material layer becomes smaller in a direction away from the central hole and the degree of compaction of the second anode material layer is substantially maintained.
5. The jelly roll assembly of claim 1, wherein the areal density of the second layer of negative electrode material remains substantially constant and the areal density of the first layer of positive electrode material increases in a direction away from the central aperture.
6. The core assembly of claim 5, wherein the degree of compaction of the first layer of positive electrode material increases in a direction away from the central aperture and the thickness of the first layer of positive electrode material remains substantially constant.
7. The winding core assembly of any of claims 1 to 6, wherein the first negative electrode material layer has an areal density that increases in a direction away from the central aperture, and the second positive electrode material layer has an areal density that remains substantially unchanged.
8. The core assembly of claim 7, wherein the compaction of the first layer of negative electrode material increases in a direction away from the central aperture and the thickness of the first layer of negative electrode material remains substantially constant, or
The thickness of the first negative electrode material layer becomes larger in a direction away from the central hole and the degree of compaction of the first negative electrode material layer is substantially maintained.
9. The winding core assembly of any of claims 1 to 6, wherein the areal density of the first layer of negative electrode material remains substantially constant and the areal density of the second layer of positive electrode material decreases in a direction away from the central aperture.
10. A battery comprising the jelly roll assembly of any one of claims 1 to 9.
CN202210209626.8A 2022-03-04 2022-03-04 Roll core assembly of battery and battery Pending CN114566720A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210209626.8A CN114566720A (en) 2022-03-04 2022-03-04 Roll core assembly of battery and battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210209626.8A CN114566720A (en) 2022-03-04 2022-03-04 Roll core assembly of battery and battery

Publications (1)

Publication Number Publication Date
CN114566720A true CN114566720A (en) 2022-05-31

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Family Applications (1)

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CN202210209626.8A Pending CN114566720A (en) 2022-03-04 2022-03-04 Roll core assembly of battery and battery

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CN (1) CN114566720A (en)

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