CN216648359U - Battery structure for improving lithium precipitation at corner of anode - Google Patents
Battery structure for improving lithium precipitation at corner of anode Download PDFInfo
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- CN216648359U CN216648359U CN202122679075.5U CN202122679075U CN216648359U CN 216648359 U CN216648359 U CN 216648359U CN 202122679075 U CN202122679075 U CN 202122679075U CN 216648359 U CN216648359 U CN 216648359U
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- 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
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- 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
Abstract
The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to a battery structure for improving the lithium precipitation at the corner of an anode, which comprises a first pole piece, a diaphragm, a second pole piece and a protective film, wherein the first pole piece, the diaphragm and the second pole piece are sequentially superposed and wound to form a bare cell; the two sides of the first pole piece are respectively provided with a long membrane surface and a short membrane surface; the coating surface density of the long film surface of the first pole piece is larger than that of the short film surface of the first pole piece, and the protective film covers the body and the side edge of the bare cell. According to the utility model, the battery structure is optimized, the corner lithium precipitation of the battery is improved, and the safety of the battery is improved.
Description
Technical Field
The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to a battery structure for improving corner lithium precipitation of an anode.
Background
In the current electronic information explosion era, the demand of human beings on the mobile power supply is increased in a blowout manner. The lithium ion battery has the advantages of high energy density, long cycle life, wide working temperature range, environmental protection, portability and the like, is the most glaring new star in the field of new energy at present, and is widely applied to various middle and high-end electronic products and high-tech equipment. The improvement of people's living standard has had higher requirement to electronic product performance experience, expects that equipment can possess overlength continuation of journey function after once charging, possesses the durability of overlength simultaneously, reaches splendid experience effect. This requires higher energy density and longer cycle life for lithium ion batteries.
The energy density of the lithium ion battery is improved by not only using high-voltage and high-capacity materials, but also performing weight reduction and slimming on the materials in design, the design is more aggressive, particularly the CB value (Cell Balance) of the 3C type battery, the CB value reflects the lithium embedding space reserved for the cathode by the anode, the CB value of the 3C type high energy density battery is about 1.04-1.06, and for the winding type lithium ion battery, the CB value of the corner arc area is smaller than that of the flat area, the actual CB value is close to 1 or smaller than 1.0 when the limit design is carried out, the stress of the corner in the formation stage is poor, the contact effect between the pole pieces is not ideal, not only inlay the lithium space not enough at circulation process positive pole corner, poor contact can make the ion transmission resistance great moreover between the pole piece, and this region is extremely easy to analyse lithium in circulation later stage, and along with analysing going on of lithium aggravation side reaction, finally cause electric core side serious deformation and inefficacy.
SUMMERY OF THE UTILITY MODEL
The utility model aims to: aiming at the defects of the prior art, the battery structure for improving the corner lithium deposition of the anode is provided, and the battery structure is optimized to improve the corner lithium deposition of the battery, so that the safety of the battery is improved.
In order to achieve the purpose, the utility model adopts the following technical scheme:
a battery structure for improving the lithium separation at the corner of an anode comprises a first pole piece, a diaphragm, a second pole piece and a protective film, wherein the first pole piece, the diaphragm and the second pole piece are sequentially superposed and wound to form a bare cell; the two sides of the first pole piece are respectively provided with a long membrane surface and a short membrane surface; the coating surface density of the long film surface of the first pole piece is larger than that of the short film surface of the first pole piece, and the protective film covers the body and the side edge of the bare cell.
Preferably, the first pole piece is an anode piece, and the second pole piece is a cathode piece.
Preferably, the difference between the coating surface density of the long film surface of the first pole piece and the coating surface density of the short film surface of the first pole piece is 0.001-0.002 g/1540.25mm2。
Preferably, when the lithium ion battery is wound into a bare cell, the long film surface is located on the outer ring of the first pole piece, and the short film surface is located on the inner ring of the first pole piece.
Preferably, the coating mode of the first pole piece is extrusion coating.
Preferably, the long film surface is formed on the first pole piece by continuous coating, and the short film surface is formed on the first pole piece by gap coating.
Preferably, the thickness of the protective film is 50-100 μm.
Preferably, the coating areal density is proportional to the CB value.
The battery has the beneficial effects that the battery comprises a first pole piece, a diaphragm, a second pole piece and a protective film, wherein the first pole piece, the diaphragm and the second pole piece are sequentially superposed and wound to form a bare cell; the two sides of the first pole piece are respectively provided with a long membrane surface and a short membrane surface; the coating surface density of the long film surface of the first pole piece is larger than that of the short film surface of the first pole piece, and the protective film covers the body and the side edge of the bare cell. Because the stress of the corner in the formation stage is poor in the existing battery, the contact effect between the pole pieces is not ideal, the lithium embedding space at the corner of the anode is not enough in the circulation process, the ion transmission resistance is larger due to the contact difference between the pole pieces, lithium is easy to precipitate in the area in the later circulation stage, and the side edge of the battery cell is seriously deformed and loses efficacy along with the aggravation of side reaction due to the aggravation of lithium precipitation, therefore, by optimizing the single-double-face coating structure of the first pole piece, the coating surface density of the long film surface of the anode piece is slightly heavier than that of the short film surface, the CB value of the corner area where the long film surface of the cathode corresponding to the long film surface of the anode in the winding naked battery cell is ensured to be in the safety range, enough lithium embedding space is reserved for the cathode, the occurrence of the lithium precipitation phenomenon is reduced, the comprehensive performance of the battery is improved, in addition, the structure of pasting the protective film covers the main body of the battery cell and even the side edge, and ensures that the stress is more uniform in the corner area formation, the contact between the pole pieces at the corner is increased, the evenness of the battery cell formation is improved, the corner contact effect is increased, the problem of lithium precipitation at the corner is improved, the protective film is wider, the battery cell main body is covered, the two side edges of the battery cell can slightly cross the corner, the problem of thickness difference caused by the narrow protective film is greatly solved, the pressing effect at the corner of the battery cell in the formation process is obviously improved, and the SEI film forming effect is improved. According to the utility model, the battery structure is optimized, the corner lithium precipitation of the battery is improved, and the safety of the battery is improved.
Drawings
Features, advantages and technical effects of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.
Fig. 1 is a schematic diagram of a bare cell according to a first embodiment of the present invention.
Fig. 2 is a schematic view of the arc length of the pole piece according to the first embodiment of the present invention.
Fig. 3 is a schematic cross-sectional view of a pole piece according to a first embodiment of the utility model.
Wherein the reference numerals are as follows:
1-a first pole piece; 11-long membrane surface; 12-short membrane face;
2-second pole piece.
Detailed Description
As used in the specification and in the claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, that a person skilled in the art can solve the technical problem within a certain error range, and that a technical effect is substantially achieved.
Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, detachable connections, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
The present invention will be described in further detail with reference to fig. 1 to 3, but the present invention is not limited thereto.
Implementation mode one
The first embodiment will be described with reference to the accompanying drawings 1 to 3
The battery structure for improving the lithium separation at the corner of the anode comprises a first pole piece 1, a diaphragm, a second pole piece 2 and a protective film, wherein the first pole piece 1, the diaphragm and the second pole piece 2 are sequentially superposed and wound to form a bare cell; the two sides of the first pole piece 1 are respectively provided with a long membrane surface 11 and a short membrane surface 12; the coating surface density of the long membrane surface 11 of the first pole piece 1 is greater than that of the short membrane surface 12 of the first pole piece 1, and the protective membrane covers the body and the side edge of the bare cell.
Because the stress of the corner in the formation stage is poor in the existing battery, the contact effect between the pole pieces is not ideal, the lithium embedding space at the corner of the anode is not enough in the circulation process, the ion transmission resistance is larger due to the contact difference between the pole pieces, lithium is easy to precipitate in the area in the later circulation stage, and the side edge of the battery cell is seriously deformed and loses efficacy along with the aggravation of side reaction due to the precipitation of lithium, therefore, by optimizing the single-double-sided coating structure of the first pole piece 1, the coating surface density of the long film surface 11 of the anode piece is slightly heavier than that of the short film surface 12, the CB value of the corner area where the cathode long film surface 11 corresponding to the anode long film surface 11 in the winding naked battery cell is ensured to be in the safety range, enough lithium embedding space is reserved for the cathode, the occurrence of the lithium precipitation phenomenon is reduced, the comprehensive performance of the battery is improved, in addition, the structure of pasting the protective film is used for covering the main body of the battery cell and even the side edge, the stress of the corner area during formation is ensured to be more uniform, the contact between the pole pieces at the corner is increased, the evenness of the battery cell formation is improved, the corner contact effect is increased, the problem of lithium precipitation at the corner is improved, the protective film is wider, the battery cell main body is covered, the two side edges of the battery cell can slightly cross the corner, the problem of thickness difference caused by the narrow protective film is greatly solved, the pressing effect at the corner of the battery cell in the formation process is obviously improved, and the SEI film forming effect is improved.
In the battery structure for improving the lithium extraction at the corner of the anode, the first pole piece 1 is an anode piece, and the second pole piece 2 is a cathode piece.
In the battery structure for improving the corner lithium deposition of the anode, the difference between the coating surface density of the long film surface 11 of the first pole piece 1 and the coating surface density of the short film surface 12 of the first pole piece 1 is 0.001-0.002 g/1540.25mm2. In the embodiment, the coating amount of the long membrane surface 11 of the anode sheet is slightly 1 to 2 points larger than that of the short membrane surface 12, the coating weight of the long membrane surface 11 is large, the CB value of the corresponding surface is larger than that of the short membrane surface 12, namely, the CB value of the corner of the outer ring of the anode is larger than that of the normal coating of the long and short membrane surfaces 12.
In the battery structure for improving the corner lithium deposition of the anode, when the battery structure is wound into a bare cell, the long membrane surface 11 is positioned at the outer ring of the first pole piece 1, and the short membrane surface 12 is positioned at the inner ring of the first pole piece 1.
In the battery structure for improving the lithium extraction at the corner of the anode, the coating mode of the first pole piece 1 is extrusion coating.
As shown in fig. 2, the difference of the CB values of the long and short films 12 at the corners of the anode is that the arc length of the outer ring of the anode (the long film 11) is smaller than the corresponding arc length of the inner ring of the cathode, so that the cathode is excessive and the CB value is smaller than that of the flat area; the arc length of the inner ring (short membrane surface 12) of the anode is larger than that of the corresponding outer ring of the cathode, the anode is relatively excessive, and the CB value is larger.
Specifically, assume that the conventional coating design areal density is (a) g/1540.25mm2The density of the other surface coated with the coating is also (a) g/1540.25mm2In this case, the coating surface density of the long film surface 11 was adjusted to (a + X) g/1540.25mm to compensate for the difference in CB value between the single and double surfaces of the anode shown in FIG. 22Wherein X is 0.001-0.002, and the double-sided area density is still (a) g/1540.25mm2The CB value of the anode long film surface 11 is slightly increased, more lithium insertion space is provided for the cathode, and the problem of corner lithium precipitation is improved from the design point of view.
Wherein a represents a conventional coating areal density value; and a + X represents a surface coating density value, and X represents a surface density correction parameter.
The working principle of the utility model is as follows:
by optimizing the single-sided and double-sided coating structure of the first pole piece 1, the coating surface density of the long film surface 11 of the anode piece is slightly heavier than that of the short film surface 12, the CB value of the corner area of the long cathode film surface 11 corresponding to the long anode film surface 11 in the winding naked electric core is ensured to be in a safe range, enough lithium embedding space is reserved for a cathode, the occurrence of lithium precipitation is reduced, the comprehensive performance of the battery is improved, in addition, through the structure of pasting a protective film, the electric core main body and even the side edges are covered, the stress is more uniform when the corner area is formed, the contact between the corner pole pieces is increased, the forming flatness of the electric core is improved, the corner contact effect is increased, the problem of corner lithium precipitation is improved, wherein the protective film is wider, the electric core main body is covered, the two side edges of the electric core can slightly exceed the corner, the problem of thickness difference caused by the narrow protective film is greatly eliminated, and the pressure effect of the electric core corner in the forming process is obviously improved, the SEI film forming effect is also better.
Second embodiment
The difference from the first embodiment is that: the long film surface 11 of the present embodiment is formed on the first pole piece 1 by continuous coating, and the short film surface 12 is formed on the first pole piece 1 by gap coating, which contributes to matching the battery structure of the present invention.
Other structures are the same as those of the first embodiment, and are not described herein again.
Third embodiment
The difference from the first embodiment is that: the thickness of the protective film of the present embodiment is 50 to 100 μm, and the coating surface density is proportional to the CB value. Specifically, the protection film width is suitable, about 1.5mm less than finished product electricity core width size, improve the whole roughness in electric core surface through pasting wideer PE protection film, contact between the positive pole corner pole piece when increasing into, improve turning into the effect, its width of conventional electricity core protection film is more than 3mm less than finished product electricity core width, can cover electric core main part most, but not cover completely at electric core both sides limit and corner, this moment through widening the protection film width, make its width be close to electric core main part, both differ about 1.5mm, just so compensatied not covering area and covering area's thickness difference, the protection film thickness is generally at 0.050 ~ 0.1mm, the turning is in the pressure that receives also can be more even, the pole piece contact can be better, SEI film forming effect greatly improves, electrical property performance is more stable.
Other structures are the same as those of the first embodiment, and are not described herein again.
Variations and modifications to the above-described embodiments may also occur to those skilled in the art, which fall within the scope of the utility model as disclosed and taught herein. Therefore, the present invention is not limited to the above-mentioned embodiments, and any obvious improvement, replacement or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Claims (8)
1. A battery structure for improving the lithium separation at the corner of an anode comprises a first pole piece (1), a diaphragm, a second pole piece (2) and a protective film, wherein the first pole piece (1), the diaphragm and the second pole piece (2) are sequentially superposed and wound to form a naked battery cell;
the two surfaces of the first pole piece (1) are respectively provided with a long membrane surface (11) and a short membrane surface (12);
the battery is characterized in that the coating surface density of the long film surface (11) of the first pole piece (1) is larger than that of the short film surface (12) of the first pole piece (1), and the protection film covers the body and the side edge of the bare cell.
2. A cell structure for improving corner lithium extraction of an anode according to claim 1 wherein: the first pole piece (1) is an anode piece, and the second pole piece (2) is a cathode piece.
3. A cell structure for improving corner lithium extraction of an anode according to claim 1 wherein: the difference between the coating surface density of the long film surface (11) of the first pole piece (1) and the coating surface density of the short film surface (12) of the first pole piece (1) is 0.001-0.002 g/1540.25mm2。
4. A cell structure for improving corner lithium extraction of an anode according to claim 1 wherein: when the battery is wound into a bare cell, the long membrane surface (11) is positioned at the outer ring of the first pole piece (1), and the short membrane surface (12) is positioned at the inner ring of the first pole piece (1).
5. A cell structure for improving corner lithium extraction of an anode according to claim 1 wherein: the coating mode of the first pole piece (1) is extrusion coating.
6. A cell structure for improving corner lithium extraction of an anode according to claim 1 wherein: the long film surface (11) is formed on the first pole piece (1) by continuous coating, and the short film surface (12) is formed on the first pole piece (1) by gap coating.
7. A cell structure for improving corner lithium extraction of an anode according to claim 1 wherein: the thickness of the protective film is 50-100 mu m.
8. A cell structure for improving corner lithium extraction of an anode according to claim 1 wherein: the coating areal density is proportional to the CB value.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202122679075.5U CN216648359U (en) | 2021-11-04 | 2021-11-04 | Battery structure for improving lithium precipitation at corner of anode |
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| CN202122679075.5U CN216648359U (en) | 2021-11-04 | 2021-11-04 | Battery structure for improving lithium precipitation at corner of anode |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117577960A (en) * | 2024-01-11 | 2024-02-20 | 江苏正力新能电池技术有限公司 | Electrode assembly, battery and electric equipment |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117577960A (en) * | 2024-01-11 | 2024-02-20 | 江苏正力新能电池技术有限公司 | Electrode assembly, battery and electric equipment |
| CN117577960B (en) * | 2024-01-11 | 2024-04-09 | 江苏正力新能电池技术有限公司 | Electrode assembly, battery and electric equipment |
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